How to Use the Popular Science Library; History of Science; General Index
Author: Garrett Putman Serviss; Arthur Selwyn-Brown
Date: 2016-02-06T00:00:00+00:00
Keywords: Science -- History; Popular science library

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Title: How to Use the Popular Science Library; History of Science; General Index

Author: Garrett Putman Serviss

Arthur Selwyn-Brown

Release date: February 6, 2016 [eBook #51133]
Most recently updated: October 22, 2024

Language: English

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*** START OF THE PROJECT GUTENBERG EBOOK HOW TO USE THE POPULAR SCIENCE LIBRARY; HISTORY OF SCIENCE; GENERAL INDEX ***

The cover image was created by the transcriber and is placed in the public domain.

Copyright, Ewing Galloway

The Majestic, Largest Steamship in the World

Popular Science Library

EDITOR-IN-CHIEF

GARRETT P. SERVISS

AUTHORS

- WILLIAM J. MILLER
- HIPPOLYTE GRUENER
- A. RUSSELL BOND
- D. W. HERING
- LOOMIS HAVEMEYER
- ERNEST G. MARTIN
- ARTHUR SELWYN-BROWN
- ROBERT CHENAULT GIVLER
- ERNEST INGERSOLL
- WILFRED MASON BARTON
- WILLIAM B. SCOTT
- ERNEST J. STREUBEL
- NORMAN TAYLOR
- DAVID TODD
- CHARLES FITZHUGH TALMAN
- ROBIN BEACH

ARRANGED IN SIXTEEN VOLUMES WITH A HISTORY OF SCIENCE, GLOSSARIES AND A GENERAL INDEX

ILLUSTRATED

VOLUME SIXTEEN

P. F. COLLIER & SON COMPANY

NEW YORK

Copyright 1922

By P. F. Collier & Son Company

MANUFACTURED IN U. S. A.

HOW TO USE THE POPULAR SCIENCE LIBRARY
BY
GARRETT P. SERVISS

HISTORY OF SCIENCE
BY
ARTHUR SELWYN-BROWN

GENERAL INDEX

P. F. COLLIER & SON COMPANY
NEW YORK

PREFACE

The final or Index volume of the Popular Science Library not only increases the value of this great set, but actually multiplies it. Volume XVI is in three parts: First, the editor, Garrett Serviss, in "How to Use the Popular Science Library," describes the way the reader may enjoy and profit most from its store of scientific knowledge in connection with his everyday experiences. Then follows Arthur Selwyn-Brown's "History of Science," an excellent foundation for the study of man's achievements in his struggle to understand and turn to his own use the forces of nature. Here is a concise record of progress from the earliest times until now—discoveries and inventions past, present, and about to come.

The third part of Volume XVI occupies nearly half the book. It is the General Index, which is as complete and as practical as it is possible for an index to be. Here, then, we have sixteen volumes on science, every work agreeable to read, every work complete in itself, and all of them, including the Index, prepared by specialists, each of whom has already gained distinction in the field he covers. The Index binds the collection into a consistent whole, making every bit of knowledge in the sixteen books available to reader or student without delay.

The style employed in the Index is a standard for such material. Volume numbers are represented by the Roman numerals, i, ii, iii, iv, v, vi, vii, viii, ix, x, xi, xii, xiii, xiv, xv, xvi. Pages are indicated by figures. All topics and subtopics are arranged alphabetically.

When you read or study the Popular Science Library, keep the Index volume at hand whenever it is convenient. It will add greatly to your interest and give you a depth of insight into these matters if you can compare one author's opinions and descriptions with those of another. If you are consulting the Library as a reference collection for information on particular topics, the Index will give you volume and page for every bit of text on the subject you are considering.

The Popular Science Library is unique in the number and standing of its authors and in the care that has been taken to make it the easiest as well as the most engrossing of all scientific collections for the reader or student to use.

CONTENTS

| PAGE
How to Use the Popular Science Library. By Garrett P. Serviss | 9
History of Science | 39-198
CHAPTER
I. | History of Science | 39
II. | Primitive Man and Early Civilizations | 46
III. | Pre-Babylonian Science | 56
IV. | Egyptian Science | 64
V. | Founding of Systematic Science in Greece | 76
VI. | Golden Age of Greek Sciences | 86
VII. | The Roman and Middle Ages | 97
VIII. | Science in the Seventeenth Century | 106
IX. | Prelude to Modern Science—The Eighteenth Century | 117
X. | Physical Sciences in the Nineteenth Century | 129
XI. | The Natural Sciences | 139
XII. | Organic Evolution, Variation, and Heredity | 149
XIII. | Chemical and Botanical Theories | 159
XIV. | Geology, Metallurgy, and Meteorology | 168
XV. | Medicine and Pharmacy | 178
XVI. | Electricity and Radioactivities | 188
XVII. | Science in the Twentieth Century | 195
General Index | 199-384

LIST OF ILLUSTRATIONS

The Majestic, Largest Steamship in the World | Frontispiece
| FACING PAGE
Eohippus—From Which the Modern Horse Developed | 16
Ornitholestes—A Prehistoric Animal of America | 17
Huntsman, Horse, and Hunting Dog of Long Ago—From an Ancient Cretan Fresco | 17
Prehistoric Paintings—An Exhibition of Copies from the Cavern at Altamira, Spain | 24
Saber-Toothed Tiger That Once Roamed Over North America | 25
Gutenberg's Printing Presses—Models on Exhibition | 32
Benjamin Franklin's Printing Press | 33
Model of the "Santa Maria," the Flagship of Columbus | 48
Curtiss Navy Racer, the Airplane That Won the Pulitzer Race of 1921 | 49
U. S. Army Dirigible on a Transcontinental Flight | 49
Electric Motor of 1834 | 64
Turning Lathe of 1843 | 64
Edison Phonograph of 1878 | 65
Whitney's Cotton Gin | 65
De Witt Clinton Train of 1831 Beside a Modern Locomotive | 80
Locomotive of the 1870 Period | 81
"John Bull," a Locomotive Brought from England in 1831 | 81
Weather and Astronomical Instruments on the Roof of Greenwich Observatory, England | 112
Mooring Tower for Airships, with the "R-24" Fastened Head On | 113
Hospital Room in Which Infected Articles Are Sterilized | 160
Modern Operating Room in Paris, Fitted with a Glass Dome and Radio Microphones for Observing Students and Doctors | 161
Edouard Belin and the Telautograph, which Transmits Pictures by Wire | 176
Lee De Forest, Inventor of the Oscillating Audion | 177
Automobile with Radio Equipment for Listening in En Tour | 177
Gifts for Tutankhamen Brought by One of his Viceroys | 192
Tutankhamen's Tomb—Bringing Up the Hathor Couch | 193
Queen Nefertiti, Mother-in-Law of Tutankhamen and Wife of Ahknaton | 193

HOW TO USE THE POPULAR SCIENCE LIBRARY

This series of books is written for all the people and not for specialists only, though it is the work of specialists who know how to explain their subjects clearly and interestingly, without unnecessary technicalities and with keen appreciation of the popular and constantly increasing desire for scientific knowledge.

The supreme importance of science in the wonderful age in which our lot has been cast was demonstrated with overwhelming force of conviction by the events of the World War. If, as certain persons assert, science may be accused of having rendered war more destructive and terrible, yet, on the other hand, no one can deny that it was science that saved the world from sliding backward into an age of despotism.

The true importance of science for everybody arises from its rapidly increasing service in the development of human industry in all its forms, for industry is the mother of democracy.

Said Gabriel Lippman, the French physicist, inventor of color photography, who died in the summer of 1921: "For thousands of years science progressed by groping and feeling its way, and coincidentally industry got slowly on by guesswork; but within the last century science has developed more than during all preceding time, while industry has sprung upon its feet and begun to march with the strides of a giant."

Notwithstanding its immense importance and the vast extent and complication of its application in modern times, science is not really difficult for any person of ordinary school education and of good natural intelligence to comprehend, provided it is presented in a clear, plain, common sense manner, in popular language with illustrations drawn from everyday life and experience. The much talked-of methods of science are, after all, nothing more than the methods of common sense, applied with systematic care by minds disciplined to a high degree of efficiency. And, in fact, the only practical difference between the mind of a trained scientist and that of any other intelligent person is that the scientist has acquired a way or habit of looking at and thinking about things and events, which enables him to get at their inmost nature and meaning more swiftly and accurately than he could do if he went to work in a haphazard manner as, in truth, his forerunners of the earlier centuries were obliged to do. The pioneer must always work by rule of thumb, but when he has exploited his field he knows better ways.

Each branch of science has its own particular methods, but it is not necessary for the average reader to study these special methods in order to become able to grasp the facts and principles that have been developed by them. The results are all thrown into a common store—or should be if science is to attain its utmost usefulness to humanity—and from the common store the great public, the people at large, should be enabled freely to draw. The object of this series of books is to form such a store of science for the people.

It may encourage those who look with some degree of timidity upon the task of trying to understand the great discoveries and achievements of modern science to know that even the ablest scientists, leaders in their own particular branches, do not pretend, or attempt, to grasp the special methods or the technicalities of any division of science except that one in which their own work is done. They stand, with regard to other branches, practically on the same footing with the unscientific reader, having over him only such possible advantages as their special training in clear thinking and in the intense application of the mental powers may give them.

Besides, science is really the most interesting thing in the world—outside of men and women—and they would be less interesting, even to themselves, if science had not transformed their lives as well as their surroundings. If one of Voltaire's favorite messengers from some other, wiser world had visited our earth a few hundred years ago, or even only one hundred, and should now repeat his call, he would be amazed, and no doubt delighted, by the changes in every feature of life and society which he would find that science had brought about, as if by magic, during the interval between his visits. He would be likely to exclaim: "Some great teacher and trainer from a more enlightened part of the universe must have been here since I saw this world before. What a marvelous new spirit he has imparted to these creatures. Through him they have become more masterful and more like sons of God."

See if you can find a single detail of your daily life that is not affected by science, or upon which science does not throw new light. It is fascinating to trace out the scientific relations of the simplest things that surround us, or the most ordinary occurrences and incidents.

Start with your first awakening in the morning, and you will perceive that there is not a thing that you see, or that in any way attracts your attention, that is not touched and illuminated by science, and often in the most unexpected and delightful ways. It is by considering these things that one may best perceive how to use the volumes of this little library. As you open your eyes in the morning you see a bright glow through the window curtain, then you know that the sun has risen.

But stop a moment. What does that mean—"the sun has risen"? The sun has not "risen" at all. But, one of the greatest facts of the science of astronomy is illustrated before your eyes—a fact that it took mankind thousands of years to find out. You are standing in the astronomer's shoes now, if you choose to wear them. This is a part of his field of science. It took him a long time to convince the world that the "rising" of the sun in the east next morning after its "setting" in the west really means that the globular earth has turned half way over during the night. If this seems simple to you now, it seemed very hard to comprehend to our remote ancestors, who, though reasoning men like ourselves, had not learned as much about the relativity of motion as we now know, though even we may be puzzled by some of the consequences that Einstein has drawn from it. And a hundred other things that astronomy has discovered about the sun and the other suns, called stars, and the other worlds, called planets, immediately rush to your mind, and you turn to the volume on astronomy to read about them.

But this is only a beginning of the string of everyday incidents that are rendered curiously interesting as soon as their scientific relations and meanings become evident to you. Science is right at your elbow to raise questions and to answer them the moment you step out of bed, and your mind begins to work.

As you throw open the window to see what kind of a day it is going to be, whether fair, or cloudy, or rainy, cool or warm, you draw your conclusions from the appearance of sky and air, but in doing that you are entering another field covered by another branch of science and included in our little library—meteorology, or the realm of the air—and you may be sure that the correctness of the conclusions that you draw from the aspect of the clouds and the feeling of the air will be greatly increased, not only in certainty, but also in interest, if you read what the students of this subject have learned about the laws and the mysteries of the rains, clouds, cyclones, barometric pressures, great winds and genial breezes, great storms and little storms; in short, the whole wonderful science of the atmosphere, that invisible, yet powerful kingdom of the air, which we are just beginning to annex to our world of activities without regard to what its natural occupants, the birds, think of such an invasion.

Now you leave the window to begin making your morning ablutions. You turn on a faucet and take a drink, or plunge hands and face into the refreshing liquid, so cool, lively, and invigorating. But a bird or any four-footed animal may find just as keen physical enjoyment in the touch and taste of the water as you do. You, however, because you are a thinking being, possess a source of enjoyment from the touch and appearance of the water that is not open to those humbler creatures, and that source of enjoyment springs from the principles and facts of another branch of science which the mere sight of the running water may call to mind if you have caught the spirit of these books—the science of chemistry, whose early history is filled with that irresistible kind of romance that pertains to the search for Eldorado, or the strivings of the human spirit after the powers of magic; for the realm of chemistry was once a kind of semi-scientific dreamland, wherein the "alchemists" delved at the same time for the "philosopher's stone" which was to turn base metal into gold, and for the wand of the magician which would give to its possessor the boundless gratifications of a Faust. Water is no mystery to the lower animals, but it is a great mystery even yet to the highest ones—ourselves—because we have been enabled to analyze it. You cannot look at it pouring from the faucet, and sparkling into bubbles, without recalling the fact that it is composed of two invisible, silent gases, and that chemistry tells us not only how to make the water disappear by taking those gases apart, but also how to form new water by making the two gases combine. The mystery is—why should this be so? It is a captivating question, and the business of the book on chemistry is to give you all possible light on the solution of that question, and others of a like nature. You will find, too, that the very latest chemistry has, strangely enough, discovered a sort of justification for the extravagant expectations of the ancient alchemists, by finding a way in which one substance may actually change, or be changed, into another, different substance—one "element" taking the form of another "element"—and also by getting clues to the existence of marvelous locked-up energies in matter, the release of which would give man control over powers that could properly be called "magical."

After finishing your toilet, with all the suggestions and remembrances of chemical science that it has produced, you start to quicken the circulation of your blood by catching up a pair of dumb-bells, or Indian clubs, or by pulling elastic cords, or banging a leather ball with your fists, as if you meant to go in for the championship of the world. Now, what taught you the value of such exercises? You are still on the ground of science, and you are practically demonstrating the principles of another of its branches—the science of health, or hygiene, which is a part of the subject of medicine, taken in its broadest signification, for, as the volume on that subject will assure you, the greatest service that this science can render to mankind is in teaching us the laws of our physical existence, and indicating, directly or indirectly, how all the functions of the body may be kept in the best working order by proper attention and exercise. You will find such things pointed out in the several sciences that deal with the body, such as physiology and medicine.

While you are making the leather ball strike the ceiling with resounding whacks, your dog, excited by the inspiring noise, bursts into the room, and interrupts your exercise with his enthusiastic morning greetings, expressed as energetically by his wagging tail as by his joyous barks and licks, all anticipatory of a lively morning run. He brings immediately into your mind the thought of still another division of science—zoölogy—to which you will devote many pleasant half-hours of reading, for it is full of most entertaining matter, as well as of matter calculated to awaken profound and useful thought concerning the relations of the many different members of the animal world to one another, and especially to their head and chief, man, to whom the supervision of the whole was, according to the Bible story, originally committed. Familiar as your dog may be to you, there are a hundred particulars of his family relationships, his descent from wild ancestors, etc., which can only become known to you through the studies that have been devoted to the science of zoölogy by curious-minded investigators from the times of Aristotle and Pliny down to our own day, when we have seen an ex-President of the United States wandering adventurously through some of the remotest portions of the inhabited globe, seeking fresh knowledge of, and personal acquaintance with, the rarer kinds of wild animals, and hunting down in their native wilds great beasts which the Cæsars used to admire from the security of the imperial seat, high above the bloody sands of the Roman arenas. And this modern ruler, after having laid down the political power intrusted to him by fellow citizens, found no occupation so attractive as that of adding something to the growing stores of science.

Painting, Chas. R. Knight. (American Museum of Natural History)

THE LITTLE EOHIPPUS. FROM WHICH THE MODERN HORSE DEVELOPED

ORNITHOLESTES—PREHISTORIC ANIMAL OF AMERICA

Photo, Metropolitan Museum

HUNTSMAN. HORSE AND HUNTING DOG OF LONG AGO

From an ancient Cretan fresco

Next, your stomach, awakened to its wants and needs by the restored circulation resulting from your lively exercises, reminds you of what will be at the same time a pleasure and a means of sustained strength for body and mind, your breakfast. Breakfast properly comes under the supervision of the science of physiology. It is also suggestive of mechanics and physics, since it has to do with the stoking of the furnace that keeps the bodily engine up to its work. Here you are face to face with a branch of science which you could no more safely neglect than an engineer or a fireman could neglect to learn the elements and principles underlying his critically important occupation. One of the first sciences to be systematically developed was that of man's body, including its structure, or anatomy, and its functioning, or internal action, physiology. You will find that correct ideas on these subjects were slow in being developed, yet even in the most ancient times men were shrewd and wise enough to understand the importance of knowing something about their own bodies, in order to be able to take proper care of them, and to deal with wounds and sickness.

It was an old saying that "the proper study of mankind is man." But that is a study which has two main branches. The first covers the subjects of physiology, anatomy, medicine, etc., while the second relates to that even more intimate part of ourselves which has ever been a fascinating mystery, and which we call the mind, or sometimes the soul. This is the theme of the science of psychology, whose name comes from that delicate, inscrutable spirit, Psyche, the Soul, which plays like a flitting sunbeam through the magical atmosphere of Greek mythology. Now, this subtle and exquisite science, often more poetic and mystic than scientific in its original character, presents itself in its more sober and practical dress to you as soon as, having finished your breakfast and prepared your bodily energies for the day's work, you begin to meditate on the problems of the day opening before you.

When you went to bed, perhaps your mind was agitated by some important matter of business through whose intricacies you could not clearly see your way. You turned and tossed on your pillow, and stated and restated the facts and arguments and lines of reasoning, but all the while they became more obscure and entangled until at last, in sheer exhaustion, you fell into a troubled sleep. But this morning, to your immense surprise and gratification, without any effort on your part, and while you are occupied with other things—putting on your clothes, hitting the ball, playing with the dog, eating your bacon and eggs, or what not—suddenly the elusive clue or solution, so vainly sought the night before, presents itself plain before you. In an instant, in the twinkling of an eye, the troublesome problem is solved, as easily and naturally as water runs down hill, and you are provoked at yourself for having been so dull and stupid as not to see it all before. But not so fast! You were stupid, to be sure, but it was not your mind's fault as you are now disposed to think, but the trouble lay in your physical fatigue. You were driving your brain too long without refreshment, and it became like an engine whose oil cups are empty. It could not receive and report the impressions of thought.

Now this kind of experience comes many times to many men and women, and it is the purpose of the book on psychology in this series to make everybody acquainted with the laws of the working of our minds through our brains. Yet, how many of those who are frequently puzzled by such things are aware that there is a branch of science, one of the most captivatingly interesting of all, devoted especially to this subject? By studying the volume on psychology you will get light on just such things as so greatly puzzled you, and haunted you, before the solution of your problem unexpectedly rose up, as it were, and stood plain before you on the breakfast table, after having for twenty-four hours resisted your utmost efforts to master it, or even to get an effective hold upon it. It is unnecessary to speak of the immense importance to all human beings of a knowledge of the laws governing the manifestations of the mind, by taking advantage of which they may get the most out of themselves with the least loss of time and expenditure of effort.

Let us keep on further along the wonderful road of science on which your feet begin almost unknowingly to tread from the moment of your awakening, and which they follow, often just as unconsciously, until you fall asleep at the close of another day; while, as we have just seen, even when we are asleep our minds are not altogether inactive, and may even secretly disentangle the puzzles of the day while our tired brains are restoring themselves with slumber. Perhaps you live in the suburbs of a city, or far from the business center, and have to take a considerable journey from your house to your place of work or business. Maybe you go by automobile, or by street car, or by a trolley route, or take a commuters' train. In any event, whether you drive your own car, or ride in one drawn by a motor or a locomotive engine, you are brought face to face with the science of physics, including, of course, not only mechanics, but also, in our own day, electricity and magnetism. If you glance at a steam locomotive, puffing and blowing, and then at a smooth, silent electric motor drawing a long train, and then at a swift automobile winding and turning with serpentine agility through crowds of slow horse-drawn vehicles—in all cases your memory must recall the long, hard road by which these things were brought about, and you must be lacking in intelligent curiosity if you do not resolve to know for yourself, not only the history of these triumphs of human invention, but the principles of action upon which they depend. If you have a car, it would be a good thing to drive it yourself and learn to take care of its machinery yourself, for thus you would go far toward mastering the elementary principles of the science of mechanics, which has done more than all other things combined to transform the face of the world we live in. You cannot, of course, acquire all this knowledge by practical experience, but by putting together what you observe with what you read in the volumes devoted to mechanics, physics, chemistry, electricity, etc., you will find that every day is a school day for you in which you have learned something new, useful, and interesting, and something, moreover, which every wide-awake person in this wide-awake age ought necessarily to know, and can know by pursuing such a course as that just suggested. Your morning's ride to work will be transformed into a delightful intellectual experience if you prepare yourself by a little daily reading to understand the construction and manner of working of all the machines, engines, and mechanisms presented on every side to your inspection.

But machinery is not everything in life. Suppose that as you ride along your eye is caught by the great beauty of the flower gardens by the roadside, their blossoms bright in the morning sunshine and sparkling with the yet undried dew, as if sprinkled with diamonds. Perhaps your attention may never before have happened to be called so strongly to these objects, and possibly you have hitherto remained almost unacquainted with the names and peculiarities of some of the most common plants and flowers. But this morning, for some accidental reason, which may have a psychological origin, you are particularly charmed with the brilliant sight, and you resolve that you will be no longer ignorant of what could, manifestly, give you so much pleasure, besides being of unquestionable usefulness. When you return home you will take up the volume on botany, and it may lead you into a realm of mental delight previously unknown to you.

If it is the springtime, you may be interested by the sight of a tall, graceful tree, as lofty as a pine, and as straight in trunk, with many exquisite blossoms hanging from the pendulous stems on its great limbs, fifty or more feet above the ground, as if it were a flower garden in the air for the special delectation of the birds. Having never heard of a flowering tree outside the tropics, you feel a keen desire to know what this one is, and thus a way of introduction, founded on keen, personal interest, is opened for you to the science of botany. And few persons can take a ride, or a walk, anywhere in city or country or park, without having attention attracted by some unknown flower or plant, or tree, and without becoming aware how much pleasure is lost, and how much useful knowledge missed, by lack of the easily acquired knowledge of these things, which anybody can have by giving to it only that amount of time which would otherwise be wasted almost as completely as if the eyes were kept closed and the mind dismissed from its home in the brain. More mysterious, and not less fascinating than flowers and trees, are the birds and insects that flit by on their own errands. To explain them you have the volume on zoölogy, the science of animal life. Botany and zoölogy together go far to revolutionize the ordinary man's ideas about the attractiveness of outdoor life.

For the cultivator of the soil, whether farmer, gardener, or fruit grower, botany, of course, is the queen of sciences—though he may not safely remain ignorant of the others mentioned, which form a brilliant court for his queen. In no direction has science lately proved itself so indispensable as in the application of botanical knowledge to the improvement of agricultural operations of all kinds. In France, always one of the richest of lands in this respect, the government has since the war made special provisions for placing instruction in botany and plant physiology, and the results of all advances in the science of the vegetable kingdom, before the pupils of the primary as well as those of the secondary and higher schools. Botanical reading and study are encouraged in every possible way. One of the most significant propositions for the extension of this educational reform consists in the suggestion that the schools in the country districts give much more attention to the various branches of botanical knowledge than the city schools do, for the purpose not only of supplying instruction that will be of fundamental practical use to the young people who grow up on the land and are to make its cultivation their life's occupation, but also of stimulating a love of the country for itself, its scenes, its atmosphere, its society, its amusements, and its simple, beautiful, and healthful ways of life.

As your train, or car, rushes through a rock cut where the roadway has been carried, without change of level or grade, through the round back of a hill, you may happen to see on the side walls of the excavation curious striations, or cross checkings, of the rock surface, or alternate strata, or layers, of varying color and texture; some composed of smooth-faced stone, of a dark, uniform color, and others of coarse granular masses of variegated hue, some of whose particles flash like microscopic mirrors in the glancing sunlight that grazes the top of the cut. Here, then, you are plunged into the wonder world of the geologist and the mineralogist, the subject of one of the most interesting of our volumes. That man must indeed be dull of intellect who does not feel a thrill of interest at the sight of these signs and inscriptions, written by the ancient hand of nature in the rocks, and telling, in language far more easily decipherable than the hieroglyphics of Egypt, the story of the gradual growth of this round planet on whose surface we are confined, like flies or ants, as it rotates and revolves in empty space, circling with us around a star, ninety-three million miles away, called the sun, which saw the birth of our world and has ever since kept it warmed and lighted with its rays.

In those layers of rock in the railway cut you see the leaves of the book of geology, infinitely older than the oldest scripture from man's hands, and relating things that occurred in those far-off nights and mornings of time that flitted over the globe ages before the human stem had set off from the trunk of terrestrial life. These geologic pages speak of occurrences in the building of the world that happened millions of years ago, and millions of years apart, though they have left marks and vestiges that the eye can discern as easily as if they had been the work of yesterday. No observant person can ride twenty miles through the country, especially in a hilly region, without having the fundamental facts of geology continually before him, and all that he needs in order to comprehend these things is a little preparatory reading, accompanied and followed by intelligent thought and observation. Anybody to whom all rocks look alike, and all hills the same, needs a little awakening of the mind. He is one of the persons had in view when this series was conceived and written, and he has no occasion to feel in the slightest degree offended by such a statement, for the simple fact that probably ninety-nine one-hundredths of his fellow citizens, and they among the best in the community, are just as unfamiliar with the plainest facts of geology as he is. Geology is not a difficult science to master in its main outlines, and there are few more fascinating when once its drift is caught. Even the beginner in the reading of the volume on geology, by seizing such chances of observation as every ride or walk affords, may in a very short time acquire the ability to read the history of a landscape from its face, to recognize the work of the glaciers in the great Age of Ice, to see where ancient streams flowed, or where molten rock has gushed up through the surface layers of the earth's crust, and even to recognize on sight some of the fossils, which are under everybody's feet in some parts of the country, and which still retain the forms of animals some of which were among the primal inhabitants of the earth, whose lines have died out, while others, though their individual lives expired tens or hundreds of millions of years ago, bear in their fossilized forms a close resemblance to modern relatives and descendants whose generations still flourish in the living world in this twentieth century of man's latest historic era.

Presently, turning from the attractions of the outdoor world, which seem just as entrancing the hundredth time you look upon them as they did the first time, particularly if you have cultivated the habit not merely of noticing but of thinking and reading about them, you take up the morning newspaper, in which most of your companions of the car are already deeply buried, and amid the political news, the personal gossip, the inevitable exploitation of the deeds of criminals, the foreign intelligence, and the social gossip that falls under your eyes, your attention is caught (this is an actual happening of not long ago) by the headline: "John Daniel, the orang-utan, is dead." This sounds odd. There has been no animal's obituary in the papers since Barnum lost his biggest elephant, and bequeathed its skeleton to science. You read further and find an interview with a professor about the human relationships, or apparent relationships, of the anthropoid apes, of whom "John Daniel" would probably have been the acknowledged king if his relatives of the woods could have understood the regard in which he was held by his white-skinned and clothes-wearing jailers. You will probably cut out that paragraph and put it aside for further consideration, remembering that there are at least three volumes in your Popular Science set at home, that on zoölogy, that on geology, and that on anthropology, in which there will be an abundance of interesting and authoritative matter bearing on this most important subject—for important you will consider it now that the death of a kind of caricature of humanity in the zoölogical garden that had so long amused the children as well as their elders with its humanlike motions, habits, looks, and pranks, has suddenly brought the whole question up among the news of the day, affording you a new light on a matter which you had hitherto thought to belong exclusively to the field of the professors of zoölogy and their students. Hereafter you will disposed to take a broader view of all these things, and will be in a better position to understand and enjoy the discussions of learned scientists when they are interviewed by newspaper men on subjects of this kind. The inquiring spirit of the time requires this concession even if in your private opinion there is no real relationship between men and apes. And, without regard to any such questions, you will find the volume on anthropology immensely interesting and informing.

Finally, as your morning's trip comes to an end, your attention is recalled from the natural to the mechanical sciences. You descend from your car or train, to go to your office. Your now fully awakened mind, alert to all the scientific relations of everything about you, can no longer keep from dwelling upon the underlying meanings of this marvelous display of realized human dreams. With the speed of the wind you are carried deep under the city's pavements, inclosed in a little flying parlor, in the midst of an artificial subterranean daylight, far beyond the reach of the solar rays, emulating the self-luminous creatures of the deep sea bottom; or you go shooting past the window of third, fourth, and fifth stories, or even above the levels of roofs, and you cannot but reflect and marvel that electricity does it all; electricity, that strange imp with blue star eyes no bigger than pin points, and a child's crown of little crinkling, piercing rays, which seemed so amusing when you were at school in the old days of frictional electric machines, when it was a great joke to give the cat a shock and see her flee with a squall, her hair standing on end in spite of herself. But now electricity has become a giant of unrivaled and terrific power, spurning the heavy-limbed Brobdingnag, steam, from its swift path, and fast making the world all its own—except its master, man, who is still, however, half afraid of his new and all-capable servant.

EXHIBITION OF COPIES OF PREHISTORIC PAINTINGS FROM THE CAVERNS AT ALTAMIRA, SPAIN

Painting by Chas. R. Knight. Photo, American Museum of Natural History

THE SABER-TOOTHED TIGER THAT ROAMED OVER NORTH AMERICA IN PREHISTORIC TIMES

This modern genie of limitless power, conjured out of his deceptive bottle, can do the smallest as well as the greatest things for you. When, upon reaching your office, you telephone to your wife that Mr. Blank will be home to dinner with you, you cannot form the slightest idea of how the miracle of distant speech is accomplished unless you are either an electrician yourself, or have read intelligently upon the subject of the applications of electricity to the motivation of all kinds of machinery, a subject to which an entire volume is devoted in our series. It would be a kind of shame and reproach to an intelligent man to be ignorant of the way his telephone works, and of the simple scientific principle on which it is constructed. If telephones, and such things, were products of nature and grew on trees, we might be excusable for not knowing exactly their secret; but being made by men, with the same limitations as those that circumscribe us all, we ought at least to understand them.

Thus, by a simple review of the series of common happenings that arrive every day to everybody, we perceive how intimately and indissolubly the various branches of science treated of in this compact library of science, are linked with all that we do, including our most unconscious acts and our most habitual subjects of thought. We have taken for illustration the morning history of a person supposed to live amid urban or suburban surroundings. Equally illuminating would be that of an inhabitant of a village or a rural district, and even more suggestive in many respects. The dweller in the country is brought into closer association with the infinitely changing aspects of nature than the city dweller enjoys. The simplest incident in the life of a person living on a farm may be the beginning of a thread of connection leading, like the clue of a labyrinth, into the heart of some of the most marvelous departments of science, and resulting in a mental revolution for the fortunate person who follows out the clue under such guidance as these volumes afford. The writer has remembered from boyhood the indelible impression made upon his mind by the finding of an Indian arrowhead in a recently ploughed field. The shapeliness of the beautifully chipped piece of flint, almost as translucent at the edges as horn, the delicate tapering point which, as if by miracle, had remained unbroken probably since colonial times, the two curious little "ears" carefully formed on each side of the flat triangular base to facilitate attachment to the head of the arrow, and the thought, suggested by older persons, that this weapon might actually have been used in some midnight attack on a white settlement, made more terrifying by the frightful Mohawk war whoop and the display of the reeking scalps of human victims in the glare of burning stockade and cabins—all these things bred a keen desire to learn the particulars of the history of the red warriors of the Five Nations, the "Romans of the New World," and also to know something about the life and customs of this strange, savage race of mankind which continued to live in an "age of stone" on a continent that had never known civilization. No volume like that on the history and development of man in this series existed at that time; but if such a book had existed and had fallen into the hands of the finder of the arrowhead, it would surely have fascinated him more than "Robinson Crusoe" did, because a boy can distinguish as readily as a grown person the superior interest of the true over the pretended, provided that the true possesses the real elements of romance.

So, too, the writer remembers having an interest in mineralogy awakened in his mind, never to be obliterated, by the sight of another plowed field, in the southern skirts of the Adirondack Mountains, whose freshly turned furrows glittered in the sunshine with thickly scattered quartz crystals, some of the larger and more perfect of which blazed across, the whole breadth of the field, like huge diamonds, and made the heart of the finder beat with an excitement akin to that of the discoverer of a Koh-i-noor. There were also some very curious "stone buttons" which one could break out with a hammer from slate rocks along the Schoharie Creek, and which, when cracked open, were found to be composed of pyrites that resembled pure silver—and sometimes gold—freshly broken. Now, things of this sort are always attracting the attention and awakening the curiosity of children living in the country, but the real pleasure and instruction that they might afford are usually missed because of the lack in the family library of popularly written books on the natural sciences—a lack that we are trying to supply.

For city children and their elders, whose eyes are constantly greeted, not by hills, creeks, ponds, rivers, woods, and fields, but by sky-aspiring buildings, railroads elevated on stilts, multiple-decked suspension bridges, electric power houses, tunnels that form a second city underground, and the thousand marvels and splendors of electric illumination at night, the volumes on physics, mechanics, and electricity and magnetism have a more immediate interest and value. What the children learn about these things in school is far from sufficient to satisfy their curiosity. They need books at home to guide their inquiries as well as to answer them. Only by that means can the diffusion of scientific knowledge, and the popularization of the scientific method of getting at the truth and the meaning of things be thoroughly effected. Science, as its history plainly demonstrates, progresses most rapidly only when a great number of minds have been led to concentrate their powers upon its problems. Great genius, it is true, rides over obstacles; yet consider how much further its energies might have carried it if the obstacles had been more or less completely removed in advance. Many a young man has been led to a brilliant career, to the great advantage of his country and his time, as a result of the interest awakened in him by the clear statements of a popularly written book on some branch of science.

One of the difficulties that persons unfamiliar with certain branches of science encounter in reading about them arises from the excessive use of technical terms, the lack of simple illustrative examples, and also, sometimes, a lack of sympathetic appreciation of the reader's difficulties. It has been a special object of this series to avoid this trouble. Ordinary textbooks are prepared for students in school and are intended to be supplemented by the personal instruction and guidance of a teacher, standing at the pupil's elbow, or readily approachable. But the reader who wishes to inform himself upon some progressive branch of science after his school days are over needs to have the teacher included in the book itself.

Then, too, there are many persons who have no comprehension of the great and gratifying power that a knowledge of some of the elementary principles and formulas of science bestows upon anybody who may take the little trouble necessary to master them, a trouble that does not imply a long course of scientific study. The "man in the street," if he possesses these easy-working keys to knowledge, can verify for himself some of the calculations of scientists which, if he did not know how they were done, would always remain for him in the category of the mysterious achievements of genius.

To illustrate, let us take a simple example—that of the Newtonian law of falling bodies. Many persons would assume on the face of it that there was nothing in this law that could have a particular interest for them. But let us see. You will find in the volume on physics that the law is stated thus: S = ½gt^2, i. e., "S equals one-half of the product of g multiplied by t squared." As you look at it you would, perhaps, as soon think of picking up a complicated tool and trying to use it for some ordinary purpose. Nevertheless, let us try. "S" in the formula means the space or distance traversed by the falling body, "g" means the velocity that the force of gravity imparts in each successive second to the body, and "t" means the time elapsed during the fall. What the formula tells us, then, is that if we observe the time during which the body is falling, and then square the number of seconds involved (multiply the number by itself), multiply this square by "g," which is represented practically everywhere on the face of the earth by the number 32, and finally divide the whole by 2, we shall have the distance that the body fell. This distance will be in feet, since the number 32, representing "g," is in feet. Now, it might be a matter of life and death, or at any rate of mental discomfort against quietude of mind, to have that rule in memory and to be able to apply it. For instance, you are on your vacation and stopping in a strange hotel, where they have put you in the top story. On looking out of the window you are dismayed at finding no fire escape, or other appliance of safety, so that your only resource in case of fire would be to make a rope out of the bedclothes and let yourself down with it. But, how far is it to the ground? How long should the rope be? Are there sheets enough on your bed to furnish it? The little formula about falling bodies will answer the question for you in five minutes. First, you let some small solid object drop from the window, and note by your watch, or by counting seconds, which everybody ought to teach himself to do, how long it takes to reach the ground. You repeat the experiment two or three times to make sure. Say the time comes out three seconds. Very well, now apply the rule: The square of 3 is 9, and 9 multiplied by 32 gives 288, and dividing by 2 you have 144 feet for the height! It is to be feared that your bedclothes rope would not be long enough; you had better send to the office for something to supplement it. But if the time of fall should be only 2 seconds, which is more likely, except in skyscraper hotels, then the calculation would give you 64 feet for the height, which you might manage with the aid of the bedclothes.

MODELS OF GUTENBERG'S PRINTING PRESSES

The models show three stages of development, the first of them at the right

BENJAMIN FRANKLIN'S PRINTING PRESS

The original is now in the National Museum at Washington

This is only a single example among many that could be given to show the usefulness and interest of many of the formulas of science which the ordinary reader looks upon as beyond the reach of any person whose occupation leads him another way. But cases of equal simplicity could be found in connection with the subjects of electricity and magnetism, chemistry, medicine, physiology, etc. Sometimes it happens that a technical word contains its own definition and explanation in a nutshell. A striking instance of this will be found in astronomy, in the word "light-year." The meaning of this word stands forth on its face—it evidently expresses the distance that light travels in the course of one year. Now, since it is known by means of direct measurement that light goes at the rate of 186,300 miles per second, manifestly a light-year must be equivalent to an enormous number of miles. In fact that number, roundly stated, is no less than 5,860,000,000,000. But to what marvelous regions of thought such a term opens the way! Yonder star is 2,000 light-years distant from the earth; then its light-waves now entering your eyes left it when Julius Cæsar was conquering Gaul, and have been speeding on their way to the earth ever since! Another star is found to be 5,000 light-years distant; then the light by which you now see it started from the star when Abraham set out from Ur of the Chaldees to settle in the Holy Land, and has not found a resting place anywhere in boundless space until just now when its tiny waves break and expire on the retina of your eye! Such treasures of knowledge and tonics to thought are scattered all through the volumes of this set, the purpose of whose publishers, editors, and writers has been to accumulate such things in small compass and in crystal clearness, for the use not only of those who, after their school days are over, still wish to keep abreast of the progress of science in all its branches—as everyone should strive to do in this most scientific of all ages—but also for those who have hitherto not had the time, or the opportunity, or perhaps even the desire, to make themselves at home in the house of science.

It may be well to add a few words on the interrelation of the different subjects treated in the various volumes of the series. This will suggest to the reader himself the best order in which to take up the reading of the books. Naturally he will desire to obtain both a clear general view of the whole field of science, and also more detailed acquaintance with its special parts, the amount of detail depending upon his particular interest in a subject. For the first purpose the preferable way would be to run first over the brief account that follows in this volume, of the history and development of science in general, and then to take up the simpler and more easily grasped branches.

But it should be firmly kept in mind that, fundamentally, science is one, having in all its branches but one aim and object, viz., the ascertainment and demonstration of the exact truth of things as far as human capacities are able to reveal and comprehend such truth, and also but one method of procedure, which is the method of common sense trained to the utmost attainable exactitude in observation and the greatest possible clearness and precision of reasoning. Science properly so-called confines itself to things that are subject to observation by the senses and to verification by repeated observation and experiment, while its reasonings and predictions are based entirely upon the unvarying sequence of the phenomena of nature, as they display themselves before us.

Science is just as one and inseparable as life, or as an organic being, and its divisions no more imply lack of unity than do the various organs and limbs of an animal, or a tree, or the different structural parts of a building. Astronomy is not entirely independent of geology, nor geology of botany, nor botany of chemistry, nor any of these of physics, nor physics of electricity and magnetism, nor the last of physiology and medicine. Accordingly the question where to begin in studying science is not one that can be answered in the same way for everybody. But the spirit is the same in all the branches.

Perhaps the best general indication of the order in which a person who has no predilection for any one branch of science should take up the various parts is afforded by their historic development. This was a result of the natural reaction of man's mind to its surroundings. The things nearest to him, and most immediately important, first attracted his attention. The broadest division would be into the science of things on the earth's surface; the science of things above the earth, in the air and the sky; and the science of things within the earth, concealed from immediate view.

If we take these in their order they naturally subdivide themselves as follows:

1—Things on the Earth—Explained by

(a) Anthropology, the Science of Man and His Ancestors, treating of his nature, origin, development, division into races and tribes, society, industry, etc.

(b) Zoölogy, the Science of Animal Life, treating of the "lower animals," and of animal life in general as distinguished from the kingdom of the plants, although the related science of biology deals with both plants and animals, its special subject being the phenomena of life in its widest sense.

(c) Botany, the Science of Plant Life.

(d) Geography, combined with Physiography, the Science of the Face, or Superficies, of the Earth, dealing with lands and seas, rivers and mountains, political divisions, etc. This is covered in our series by the volume on Physiography.

(e) In this compartment several branches of science may be grouped, since they are all the product of study of things encountered on the earth's surface. They are:

Physics, the Science of the Forces of Nature, dealing with the laws of the inanimate world around us, including the phenomena relating to solid, liquid, and gaseous bodies and substances.

Chemistry, the Science of Matter and Its Changes, dealing with the atoms and their constituents, and with the combinations of atoms into molecules to form the various chemical elements, etc.

Electricity and Magnetism, the Science of Power, fundamentally underlying all other branches, and through its investigation of the nature of the constituents of atoms—the electrons—going deeper into the constitution of things than chemistry itself. In fact this science, in some respects, blends with chemistry, although it is quite separate when it deals with the mechanical developments of electromagnetism.

Medicine, the Science of Health, Physiology, the Science of the Body, Psychology, the Science of Human Behavior, Mechanics, the Science of Machinery, etc., also naturally fall into this category of Things on the Earth.

2—Things Above the Earth—Explained by

(a) Astronomy, the Science of the Heavenly Bodies.

(b) Meteorology, the Science of the Atmosphere, rains, winds, storms, fair and foul weather, the changes of the seasons, and essentially related to the new and fast developing art of aerial navigation.

3—Things Within the Earth—Explained by

(a) Geology, the Science of the Earth's Crust, or shell; which also deals with the various stratifications of the rocks, superposed one above another, and containing in the shape of fossils, and other marks, a wonderful record of the character and development of the living forms that have inhabited the earth during the long ages of the past. Of course some of the phenomena dealt with by geology are manifest on the earth's surface, and others, like volcanoes and earthquakes, hot springs and geysers, are partly subterranean and concealed from sight and partly evident by their effects on the surface.

(b) Closely associated with Geology are Mineralogy, the Science of the Constitution and Structure of Rocks and of Mineral and Metallic substances; Vulcanology, the Science of Volcanoes, and of earth disturbances in general; and the Science of Mining, which has several branches, and forms the basis of enormous industrial developments.

It is manifest, as before said, that the reader must be his own best judge as to the precise order in which to take up the perusal of the volumes in which this immense mass of scientific knowledge is presented. But, where there is no predisposition to choose one subject rather than another, or where there is a desire to follow, as nearly as may be, the natural line of development of human knowledge, it would be well to take first, after the history, the volume on astronomy, a science that from the beginning has had a peculiar power to awaken intellectual curiosity; then that on anthropology; then the various so-called "natural history" subjects, leaving the mechanical and the more technical subjects for the last.

Or, the reader might first take up the subjects of personal importance to every human being—Medicine, the Science of Health; Physiology, the Science of the Human Body; Psychology, the Science of the Mind—every one of which is essential to the proper care and preservation of life; and afterward study the other branches in the order already suggested.

Garrett P. Serviss

CHAPTER I
HISTORY OF SCIENCE

The romantic history of science shows how the discoveries of the greatest human minds, slowly operating since the remotest times, have made possible our present-day civilization. Few studies are worthy of greater attention; no other department of knowledge affords more real pleasure. Whoever clearly understands the history of science possesses intellectual advantages over those who are ignorant of the causes that have led to the establishment of the basic principles of our modern industrial arts and applied sciences. Standards of comparison are furnished by the history of science which illuminate many of the wonders of to-day, develop alertness of mind, and afford a never-ending train of suggestions for thought.

The term science means knowledge. It was derived from the language of the Romans. It is well to have a clear idea of the meaning of the word. Everyone knows that it has to do with certain kinds of knowledge; few know the particular kinds it embraces. It does not mean the mere knowledge of a single fact. It does not mean a knowledge of something which has to be done. Long before science was born, our early ancestors observed many isolated physical, philosophical, and religious facts. They knew that day followed night, that the stars moved, that every day the sun progressed over the arch of the heavens. Such facts did not constitute science.

What we know as science began when man commenced to compare one fact with another, to classify phenomena, and to arrange his knowledge systematically. Order, method, system, are basic principles of science. The best description would, therefore, appear to be systematized knowledge of any kind which had been gained and verified by exact observation and correct thinking. The whole field of human knowledge is now methodically formulated and arranged into rational systems. Modern science may, therefore, be said to embrace all our exact knowledge. Its province is enormous; its subdivisions are limitless.

Science takes no account of knowledge which is not exact. Many people acquire valuable information which they profitably use in business, but which they are unable to communicate or describe to others because they do not actually understand it.

Farmers and flower growers often possess important practical knowledge of facts which are embraced by the principles of the sciences of agriculture, botany, and biology. But their practical knowledge is not true science. It is rather like an artist's intuitive impulse. It is not the result of scientific analysis, and there is no tangible, communicable residuum.

There could be no science if men did not discover principles of knowledge which can be communicated to, and made available for use by others. Scientific knowledge must be stripped of all traces of emotionalism and personal convictions. True science is, therefore, depersonalized knowledge.

The history of science shows how our exact knowledge has been developed along irregular paths but with progressive advances. There have been long periods during which little apparent progress was accomplished, which have been succeeded by others made memorable by brilliant discoveries.

We must constantly bear in mind that many of the truths generally accepted to-day were doubtful or novel theories at some previous period. The history of science shows the enormous mental effort expended in testing and developing what now appear to us as commonplace truths.

Basic principles like those of algebra, geometry, and the planetary motions were tested during several thousand years before they were finally accepted as true.

The human intellect at the dawn of history was similar to what it is to-day. But it was not exercised as we exercise ours because it did not have adequate materials and opportunities. For the same reason science made slower progress in early times than it does now. Progress is cumulative. Each advance helps that which follows. The functions of a scientist are to struggle against individual views, and to provide an explanation of phenomena which may be accepted as true by other minds. Ascertained facts must be classified and then sequence and significance recognized from an unbiased viewpoint.

The history of science is the written record of countless experiments, theories, and experiences of mankind which have been submitted to the tests of scientific methods.

While it is true that science embraces all knowledge its real scope is limited to knowledge which is reducible to laws and can be embodied in systems. The human mind unites all knowledge by a single thread, but we have to chart and map it into larger and smaller divisions which we define by the methods, basic concepts, and plans used in developing them.

We may now see how it is that the boundaries of any science are merely approximate. The general grouping of the sciences is likewise approximate. The first large group includes the abstract, or formal, sciences such as mathematics and logic. The other great group comprises the concrete sciences dealing with phenomena as contrasted with formal relationships. Chemistry, biology, physics, psychology, and sociology belong to the concrete group.

At the beginning of history man is discovered observing the great phenomena of Nature and struggling to learn their laws and to explain them. Religion is both emotional and intellectual, and through these qualities it attracted primitive man while he was attempting to gather light on the riddles of the world. It was through religion that science was born.

Recent researches into primitive beliefs have shown in a surprising manner the psychological unity of man. In all parts of the world, in all periods of history, and under all conditions, the minds of men, in their natural reactions against the basic factors of existence, operate in similar ways. There is a remarkable resemblance in the mental processes of men. The laws of thought appear to work automatically in all men. The minds of prehistoric people worked like those of men to-day. The impressions of the senses appear to be interpreted in similar ways by all peoples. Here is the explanation of the numerous resemblances we find in national histories, national folk lore, and national religions. They differ much in innumerable details, but possess many resemblances in their great fundamental conceptions. Normal man has always been religious. Mankind has always assumed definite attitudes toward the universe and this has resulted in the universality of religion.

Early men the world over appear to have been as eager to learn the keys to the riddles of the universe as was the boy Longfellow sang about in the following stanzas:

Nature, the old nurse, took
The child upon her knee,
Saying: "Here is a story-book
Thy Father has written for thee."

"Come wander with me," she said,
"Into regions yet untrod;
And read what is still unread
In the manuscripts of God."

And he wandered away and away
With Nature, the dear old nurse,
Who sang to him night and day
The rhymes of the universe.

And whenever the way seemed long,
Or his heart began to fail,
She would sing a more wonderful song,
Or tell a more marvelous tale.

Modern science has developed from this instinctive human desire to read Nature's story-book and understand her marvelous tales.

Early struggles of mankind taught that human behavior must be regulated in accordance with rigid moral laws. This promoted the primitive social processes which were early concerned with religious beliefs as well as with magic and medicine. Two of the earliest beliefs universally accepted were that we possess souls and that our personality persists after death. These basic principles of faith have caused extremely beneficial results to follow in the development of knowledge.

Some of the American Indians and other primitive peoples of to-day still live in the belief that the heavenly bodies, the sky, sea, and earth, as well as plants, animals, and men, all belong to a vast system of all-conscious and interrelated life, in which the degrees of relationship are distinguished by the degrees of resemblance.

Religious beliefs were developed from struggles to conceive the inconceivable and discover the infinite. Religions led to studies of mysteries and ceremonies and rites. Magic developed and this also had its customs, dogmas, and rites. The difference between magic and religion was that the magician was consulted by his personal friends, whereas the holders of religious beliefs had a common bond uniting them in one strict form of worship. Magic was not systematized, while religion was a unified system of beliefs and practices relative to sacred things, and chiefly to the regulation of moral concepts and conduct.

The intimate association of religion, magic, necromancy, and science continued until the early Greek era. There were many temples erected in Greece and dedicated to Æsculapius, the god of medicine. Cures were believed to be effected through the valuable offerings made to the god by patients and their friends. It was thought that the ways to health would be indicated to them by the god through dreams.

Recent investigations of the representative ceremonial rites of the aboriginal peoples of Australasia and of North and South America have yielded a remarkably rich fund of information on the causes and conditions which operated in prehistoric eras in developing the mental, moral, and physical sciences.

Some of the most romantic stories ever developed by the human intellect are to be found in recent scientific works dealing with the history and principles of the tribal customs, ceremonies, and religious rites of primitive peoples. The early chapters in the history of man's mental development and the evolution of science from distant origins in mystic forces, through magic and necromancy to religion and philosophy, must give abundant pleasure to all thoughtful persons by showing how it came that the high state of civilization now attained was brought about by slow processes, operating through immense periods of time and blossoming only during the past two or three thousand years. A study of these stories cannot fail to show how intimately science has been associated with religion, why every normal individual is essentially religious, and why the continuation of our civilization, and the very existence of the human race, are absolutely contingent upon the recognition of the moral laws, in the future as in the past. The history of science establishes the fact that moral sanctions, which require religious ceremonies to keep them vital, are the essential bases of human progress.

CHAPTER II
PRIMITIVE MAN AND EARLY CIVILIZATIONS

The development of scientific history has not followed a uniform course. Progress has been rhythmic. There has been always a reaction coming in the steps of brilliant discoveries. Periods of feverish experimental activities have been succeeded by others during which little apparent progress was made.

Such dull intervals seem to have been necessary for developing, formulating, classifying, and testing the innumerable details and inferences that the discoveries of the active periods produced.

While mankind in general has contributed to the total of our intellectual treasures, some races have been more active in this way than others. For this reason it is advisable to briefly survey the more recent discoveries about the ancestors of existing peoples.

Indo-Malaysia, parts of central Asia, and the valleys of the Tigris and Euphrates rivers in Mesopotamia are variously credited with having been the cradle of the human race. It should be understood, however, that we are only permitted to speak authoritatively of existing races, because the land forms of the earth have undergone such remarkable changes that we can know little definitely about the earlier periods of human history. For the purposes of the history of science, while bearing in mind these qualifying suggestions, we may accept the statement that man's ancestors originated in proximity to India.

It was around the waters of the Persian Gulf that the earliest known civilizations arose. The people who founded them came from central Asia. They had reached a considerable degree of culture, which suggests that they themselves came from earlier centers of civilization.

The study of prehistoric antiquity is termed archæology. Its principal periods have been divided, for convenience, into the Stone, Bronze, and Iron Ages. Each of these is distinguished by the substances used for tools. In the Stone Age men used stone spearheads, arrows, and knives, whereas in the Iron Age similar things were made of iron or copper.

The science of mankind is known as Anthropology. It deals with the innumerable steps in the evolution of mankind from remote periods, and with the primitive development of the arts, sciences, and religion. Yet it is one of the youngest of the sciences.

One of its essential teachings is that heredity and racial predispositions play, and always have played, more important parts in man's evolution, and in the development of civilization, than environment and education.

Hereditary tendencies, such as the religious, moral, and æsthetic instincts have been indispensable in preserving and developing all the races of mankind.

Moral discipline has been the chief factor in self-control, and therefore in civilization. It is because the moral sense has proved so beneficial to the human race, and is the most powerful of our instinctive desires, that mankind always has been and must be religious. It controls man's knowledge, desires, and will, and has dominated the race since our early ancestors began to think.

When we recognize this fact we can readily see that anything which tends to oppose the moral or ethical sanctions, or detract from religious beliefs, is injurious to civilization and human progress. The histories of religion, ethics, and æsthetics plainly develop the rôles which have been played by moral self-discipline in the protection and development of mankind, as well as of knowledge and science.

The moral control of individuals acts also upon society generally, and upon whole racial and national groups. The ethical ideals assist each individual mind to realize its own end and at the same time tend to influence the tribal and social mind to attain a common end. This great moral, instinctive force, which has played such an immensely valuable part in developing civilization and science, is known as the human social and national conscience. It acts both individually and collectively.

European races have been divided into classes corresponding to the prevailing cephalic indices. The longheads are grouped as the Nordic, or Baltic, subspecies, because they were formerly numerous around the Baltic countries. People of this group are distinguished by tall statures, fair skin and hair, good physique, and light colored eyes. These peoples include the Scandinavians, Anglo-Saxon, and certain important Teutonic groups, as well as Asiatic peoples who are known as the Aryans.

Copyright, Ewing Galloway

MODEL OF THE SAILING VESSEL "SANTA MARIA," THE FLAGSHIP OF COLUMBUS

CURTISS NAVY RACER, THE AIRPLANE THAT WON THE PULITZER RACE OF 1921

U. S. ARMY DIRIGIBLE ON A TRANSCONTINENTAL FLIGHT

The most important rôles in the development of modern civilization, art, industry, and science have been played by representatives of the Nordics.

The Iberian, or Mediterranean, subspecies, ranks next in importance. The peoples of this great racial division originally occupied the countries between the northern Atlantic coast of Africa and the confines of the areas of the Nordics around the northern provinces of France. They spread down the Mediterranean and over large areas in Asia. Their skulls are long, but differ from those of the Nordics in their absolute size. Their stature is lower, and weaker than that of the Nordics, while their hair, eyes, and skin are dark or black. The Welsh, the Moors, and the early Greeks are chiefly classed with the Mediterranean group. The Carthaginians, Phœnicians, Egyptians, and Etrurians were members of it.

The roundheads comprise the Alpine subspecies. This is the strongest numerical group to-day. It is characterized by small round heads, short bodies, dark hair, and dark eyes. It is of Asiatic origin and includes the Slavs, modern Greeks, Italians, Germans, Austrians, Swiss, the pre-Nordic Irish, French, and Belgians. The first Alpine invasion of Europe began about 10,000 B. C. There were many subsequent ones through the plateaus of Asia Minor, the Balkans, and valley of the Danube. They reached England about 1800 B. C., and formed small colonies in Ireland, the descendants of which now call themselves Celts and are clearly distinguished by the characteristic Alpine indices. This race is now so well acclimatized in Europe that most of its Asiatic traces have been lost, and its round skulls and dark eyes and hair are the only reminders of its Mongolian origin.

Members of each of these three great racial groups of mankind have throughout the ages contributed to the development of the sciences and arts. The Nordics began to appear in European history as agricultural tribes, speaking Aryan languages, like Celtic and Welsh, who swept down from the north and pushed the earlier settlers back through their irresistible arms, which were made of bronze and later of iron. The earlier settlers were still furnished with arms and implements of the Stone Age.

There was a much older intellectual people than the Nordics settled in Europe. The people of this race, about whom we have learned through recent archæological researches, are known as the Cro-Magnons. They lived between 25,000 and 10,000 B. C. Their skulls were distinguished from those of the Nordics by their pronounced cheek-bones and broad faces. Their culture, as their favorable cephalic index would suggest, was of a high character. Numerous drawings and art works of theirs, which have been preserved, place them among the world's superior peoples.

Soon after the settlement of the Cro-Magnons in Europe, and their intermarriage with the earlier settlers, their physical development and stature began to decline. They were finally absorbed and destroyed by the inferior peoples among whom they dwelled. Their disappearance, like that of the ancient Greeks, who appear to have been the most intellectual people the world ever produced, shows how the upward development of human physical and intellectual qualities is constantly injured by the contacts of superior and inferior races.

The scientific discoveries made prior to the Iron Age, or about 2000 B. C., were not numerous. The struggle for life was so intense that few had opportunity for contemplation and philosophic reflection. It was subsequent to the discovery of the basic principles of metallurgy, in the Iron Age, that science began rapidly to advance. The benefits bestowed upon mankind by the employment of metals reduced the sharpness of life's struggles, permitted and instigated reflection, and provided means for experimentation.

Modern history begins with the peoples of Mesopotamia. There were cultured peoples east of the Tigris and Euphrates, in Persia, India, Mongolia, Tartary, and China before the founding of Babylon. But we are more instructed about the Babylonians and Assyrians than about earlier Asiatic races.

The Babylonians and Assyrians appear to have originated in central Asia and to have migrated to Arabia about 10,000 B. C., and perhaps earlier. They were well settled in Arabia before the Egyptian pyramids and other Semitic memorials were planned. They brought with them from the farthest Orient many important contributions to civilization and culture, and developed many others.

These were religious, philosophical and keen commercial peoples. They shaped the organization of modern religions. The Babylonians reduced the world of gods to a single system with classifications distinguishing between major and minor deities, and between those of heavenly, or stellar, and earthly habitats, and those of time and space. They developed many religious myths of the Creation, the Flood, Paradise, and others which were subsequently embraced by other religions.

Both the Babylonians and Assyrians composed beautiful hymns, prayers, parables, and religious tales, and had numerous elaborate religious customs, rituals, ceremonies, and festivals conducted by priests, nuns, and acolytes.

Anu, or Anum, the God of Heaven, was the principal Babylonian deity, while Ashur was the leading god of the Assyrians.

Religious studies and rites occupied a large portion of the time of these peoples and, consequently, their temples, monasteries, schools, and other religious buildings were large and numerous. Their architecture was elaborately artistic. This was one of their incentives to scientific invention. They made important discoveries in all the basic physical sciences, like chemistry, physics, metallurgy, and mathematics, to enable them to improve their buildings and to embellish them with paintings, pictorial tiles, and fancy metals and textiles. They had excellent professional men, artists, jurists, bankers, contractors, and scientists. They were fond of literature and founded extensive libraries. Music and musical instruments were very popular with them. Their cuneiform writings, as disclosed by numerous beautiful stone and porcelain tablets which have come down to us, were excellently done.

The fragments of literature, laws, and religious policies that we are acquainted with indicate that the numerous Babylonian and Assyrian settlements in each great empire possessed social and political conditions similar to those of our days. Science and art were then sufficiently advanced to enable these ancient people to live as agreeable, moral, and legally secure lives as those of any subsequent peoples.

The Chinese appear to have been making similar progress to that of the Babylonians about the same period. It would seem that both these peoples were in contact with a similar but earlier cultured race in central Asia. Although the early Chinese were a religious people, they appear to have been more philosophical than the Babylonians. This enabled them to make further progress in the abstract sciences. In subsequent years they made rapid strides in the physical sciences, as will be shown later.

The Egyptians came into prominence toward the end of the Babylonian and Assyrian empires, and for many centuries played a great rôle in developing civilization. The numerous benefits which they bestowed upon the world by their researches in science and art are not fully appreciated.

Early history pictures two great Asiatic races struggling for supremacy in India. They were the Aryans, a fair-skinned people, and the Dravidians, a colored people. The Aryans succeeded in displacing the Dravidians in the great plains, upon which they settled and developed large cities, important world commerce, and contributed great art works and scientific and philosophical discoveries to the world's stores. The Dravidians retired to the hill country, where their representatives still live.

The minds of the various Indian peoples have always been strongly philosophical. This led them to the development of numerous religious sects and philosophical systems, and they made important mathematical discoveries. While the scientific bent of the ancient Greeks was of a concrete nature, which tended toward geometrical proofs for scientific problems, that of the ancient peoples of India was toward numerical symbolism and arithmetical proofs. We find that when the Greeks were developing geometry the Indians were contributing to arithmetic and algebra.

The Chinese closely resembled the ancient Indians in the philosophical tendency of their minds; but, owing perhaps to the different conditions under which they lived, they were more concrete in their ideas. They also made progress in mathematics and developed medicine, chemistry, metallurgy, and many of the sciences which were applied to commercial and industrial uses. The progress made in mathematics in China was transmitted to Egypt, and therefore to Europe, through India. Among early Chinese discoveries in mathematics were methods of solving numerical equations and the development of magic squares and circles, which gave a great stimulus to studies in geometry and astronomy.

The Arabs, Greeks, and Romans took up the discoveries of the Asiatic peoples, and the Egyptians enlarged them and passed them forward to us. The Arabs solved cubic equations by geometrical means, perfected the basic principles of trigonometry, and made great advances in mathematics, physics, chemistry, and astronomy.

A survey of the early history of science indicates that from the remotest period man was engaged in grappling with the great principle of causation. Progress was necessarily slow at first on account of the scarcity of tested data. Then it became more rapid. Soon after the founding of the great city of Babylon we find that the Babylonians were possessed of enough knowledge of the arts and sciences to enable them to become world traders and great industrial undertakers. They built many cities and lived highly civilized lives. The history of modern science may very properly be dated from the building of Babylon.

CHAPTER III
PRE-BABYLONIAN SCIENCE

The transcending wonders of the phenomena of the heavenly bodies attracted the attention of primitive man at an early period of his intellectual development. The succession of day and night, the phases of the moon, comets, meteorites, the eclipses of sun and moon, the recurrence of the seasons were observed and recorded. In this way, through long uncivilized times, many scientific facts were noticed and handed down by tradition, and probably were among the first scientific data collected. We have no means of determining when the primitive science of astronomy became systematized, although there are reasons for believing that it was roughly outlined at a remote date.

There was a tradition among the Babylonian priests that their astronomical observations and records went back to a period of more than 400,000 years. This statement was believed by the people of antiquity, and was made to Alexander the Great during his Indian campaign.

Astronomy appears to have been developed into an organized system by the primitive peoples of central Asia. It was carried to China, India, and Arabia by learned travelers. There were government astronomers in China before the year 3000 B. C., and history records that two of these officials, named Ho and Hi, were beheaded in the year 2159 B. C. for being careless in their work and failing to issue a timely prediction of a solar eclipse.

Chinese history also relates that the Emperor, in 2857 B. C., issued an edict recommending the study of astronomy. From these and other historical references we learn that nearly 5,000 years ago astronomical science was not only well developed, but that its educational value was recognized.

While attention was being given to the study of astronomy in China, this science was independently developed in India. The astronomers of India invented a different system from that of the Chinese, and compiled numerous astronomical tables which were published and widely used as far back as 3102 B. C.

These early astronomical studies resulted in the division of time practically as we know it to-day. The Babylonians had a week of seven days. The days bore names of the planets and were divided into hours and minutes. Days were combined into months and years. The Babylonian and Chaldean astronomers, like those of China and India, were important men and were credited with great learning.

The Babylonian month began on the evening when a new moon was first observed. An adjustment was made necessary between the months, owing to the fact that the actual lunar interval is about twenty-nine and a fraction days. Numerous astrological observations were made with the view of obtaining data to facilitate the monthly adjustments. The taking of these observations was made easier by maps of the heavens which were recorded on baked clay tablets and prisms. Similar maps of the world, with positions fixed by astronomical observations, were likewise made in Babylonian times.

The usefulness of astronomical observations and predictions led to the belief that they could be employed with advantage for wider purposes. The astrologers endeavored to deduce omens and forecast horoscopes. In order to facilitate their calculations, the astrologers invented calculating and time-dividing machines. Tablets from the royal library at Nineveh indicate that Chaldean astrologers possessed mechanisms which divided the hours of the day by mechanical means. These were forerunners of modern clocks and timepieces.

These early scientists represented the earth as a vast circular plain, intersected by high mountain ranges and surrounded by a large river, with other mountain chains which lost themselves in an infinite ocean. The heavenly vault was believed to be supported by the highest peaks of the outlying mountains. It was owing to the peculiar nature of this cosmogony that the pre-Babylonians and Babylonians were unable to develop a satisfactory mechanical view of the world. The world had to wait for an adequate mechanical theory before general knowledge could be advanced, so that men like Newton and Laplace could correct the errors of early theories and furnish a sound working hypothesis.

The advancement of science requires methodical observations and the use of the highest powers of the imagination. It is thinking in picture-like figures that supplies primitive reasoning. While pure reasoning deals with abstract, verbal images, the more concrete picture-thinking deals with object-images. The differences between thinkers and dreamers is chiefly in the way their minds act. But even thinkers are supplied with thought material by the elementary mental operation of picture-thought, dreams, or dream-thinking. Science needs the active use of the imagination to anticipate experience and suggest the issues of a process in course of action. Most great inventions, and probably all primitive inventions, were stimulated by imagination. But the imagination, unless skillfully directed, is liable to numerous errors. That is why in all ages there has been much error in connection with knowledge. There could, however, be little or no progress without imaginative work. It is only within very recent years that the modern sciences have been stripped of much absurd matter derived from crude imaginative work. When we bear this in mind, we have the key to the part played by ancient myths, magic, and ceremonies in developing civilization.

The term magic is derived from the Persian term for priest. The magi, or priests of Zoroaster, their religion, learning, and occult practices had important world-wide effects just before the Babylonian era. Magic is a pioneer of religion, philosophy, and science.

Medicine was benefited, in some ways, by the priests seeking means for dealing with the work of the spirits of evil. Chemistry and metallurgy were also advanced, and new realms of knowledge were opened even by magicians.

The magic of the Babylonians survived their empire. It was handed over to the Egyptians and contemporary peoples, and was in turn passed down to the magicians and alchemists of the Middle Ages, and to the dramatists, poets, and novelists of all ages.

The accumulation of scientific facts was greatly facilitated by the improvements made by the Babylonians in the manufacture of earthenware tablets, scrolls, and prisms. Beautifully drawn cuneiform picture signs recorded on these all the knowledge of the day. These stonelike records were filed away in many monasteries and libraries. Subsequently, letters were invented, alphabets were formed, and writing displaced the hieroglyphic symbols.

The invention of alphabets made reading easier. This resulted in giving an impetus to education which has had cumulative effects right down through the ages.

We are now in a position to realize why scientific discoveries were made very slowly, and at long intervals apart, in early times. Facts had to be accumulated, studied, grouped, and compared. Accounts of these studies had to be pictured and stored away for future use. Only exceptionally learned men did this. But when alphabets were invented and education increased, numerous minds became active and there was a great extension of thought, experimentation, and philosophical contemplation. This was followed by the establishment of new religious houses, schools, and philosophical academies, at all of which the ablest men of the day emulated the scholars in formulating theories and making inventions.

Soon after the perfecting of cuneiform writing in Babylon, characters were devised for representing numbers. A vertical, arrowlike wedge represented the figure 1, while a horizontal wedge stood for 10. A vertical and horizontal wedge, placed together, signified 100. Other arrangements of these characters meant that they were to be multiplied, subtracted, divided, or added together. In this simple manner all kinds of arithmetical results could be recorded.

The Babylonian mathematicians were familiar with decimals, integers, and fractions, and their tables and records of astronomical and engineering calculations reveal a remarkably high degree of mathematical ability, indicating that peoples who preceded us by several thousands of years were familiar with the more important calculations requisite in trade and industry as well as for astrological computations.

Babylon was a great world metropolis. It occupied a position similar to that occupied by London to-day. Its merchants were engaged in world-wide commercial operations which needed good systems of bookkeeping and accountancy. These, in turn, presupposed a highly developed arithmetical system. Practically all the arithmetical calculations used in commerce to-day were employed by them. Their accountants, like those of China to-day, used the abacus, or calculating machine.

A lucid illustration of the accuracy of ancient calculations, the efficiency of their reports, and the confidence with which they executed intellectual duties is afforded by the following translation of a Babylonian astronomer's official report:

"To the King, my lord, thy faithful servant, Mar-Istar.

"... On the first day, as the new moon's day of the month of Thammuz declined, the moon again became visible over the planet Mercury, as I previously had predicted that it would to my master the King. My calculations were accurate."

The records of Babylon furnish us with a wealth of documents of this character.

The numerous peoples of India have always been divided into castes. This has resulted in the pioneering work in science falling to the priests. However, the principal priests were among the most intellectual men of each generation and, as they traveled in search of instruction, India was always in contact with the progress made in China, central Asia, and Babylonia. These great centers of ancient learning progressed together.

The Indians were able mathematicians and discovered and developed at an early period what is now known as "Arabic notation." In this work they were assisted by the Babylonians.

The Indians, like the Chinese and Babylonians, solved problems in interest, discounts, partnership, the summation of arithmetical and geometrical series, and determined number changes in combinations and permutations with ease. They were also proficient in algebra, the extraction of the roots of numbers, various classes of equations, and the principles of trigonometry.

The Chinese have always been good mathematicians. It is probably due to this fact that they have at all times been such able traders and bankers.

We are not so familiar with the works of Chinese mathematicians in pre-Babylonian times as we are with the Indian; but the references of contemporary writers indicate that the Chinese scientists were as able and active as their contemporaries.

We have remarked the high degree of perfection which was attained in the Babylonian era by scholars in science and mathematics. Similar perfection was attained in art, industry, law, and medicine. The wonderful law work that has come down to us under the name of the code of Hammurabi indicates not only the extensive progress which had been made in law, but incidentally through its references the progress of agriculture, industry, commerce, and business.

Many references in the Hammurabic code, written about 2300 B. C., show that the medical profession had attained considerable advance in Babylon. Surgeons were daring operators. They commonly performed operations for cataract. Many of the common major operations now performed by surgeons were also done by the ancients. They were experts at setting fractured bones. The physicians made effective use of drugs. Many drugs employed to-day were known to them.

The discoveries of the early oriental nations were collected and developed in Babylon. The entire fields of science, mathematics, geometry, agriculture, astronomy, philosophy, and art were focused in Babylon and handed down to the Egyptians and the Greeks. Much credit that is given to ancient Greece should be shared also by Babylon. It was from Babylon that Greece obtained the principles of its civilization, arts and sciences. Even Greek architecture and sculpture were originally derived from Babylon.

CHAPTER IV
EGYPTIAN SCIENCE

The early civilization in Egypt developed in the ancient cities of Thebes and Memphis. Authorities on the dawn of history in Egypt are unable to definitely account for the origins of the various peoples who have ruled the land. One school contends that the early negroid inhabitants originated in Africa. Another school opposes this view and suggests an Asiatic origin. Each of these schools can marshal facts to sustain its contentions. The truth is that Africa was inhabited at such an early period that we are unable to fully trace back the movements of its races.

Man was divided into species and subspecies at a very remote period. The dominant peoples in each country, in each era, were the successful contestants in long conflicts for supremacy. Many races have vanished without leaving any traces beyond reversional strains which still come to the surface at times in families living to-day. The laws of evolution, only recently deciphered, are the sole means we possess for learning about many of the long-perished species of men.

A few races, too weak to ever gain supremacy and themselves to occupy districts, or countries, have survived by dwelling among stronger races. The Ainus, in Japan, and the Jews in Asia and Europe, are well-known examples.

MODEL OF AN EARLY ELECTRIC MOTOR

The original was invented by M. H. Jacobi in 1834 and was used in 1838 to propel a boat on the Neva at St. Petersburg.

MODEL OF AN EARLY TURNING LATHE

This mechanism was invented by Thomas Blanchard in 1843. He also invented a lathe for turning gun barrels.

Copyright, Underwood & Underwood

AN EDISON PHONOGRAPH OF 1878

The sound record was made on a sheet of tin foil vibrated by the voice.

WHITNEY'S COTTON GIN

This device, invented in 1793, revolutionized the cotton and cotton manufacturing industries.

Egypt, owing to its remarkable geographical situation between Asia, Europe, and the vast continent of Africa, has been a great highway for race migrations. Many peoples have lived and ruled there and passed on before incoming tides of new and more vigorous peoples. Each race, undoubtedly, during its residence in Egypt contributed to the general fund of Egyptian knowledge and customs and assisted in the development of science.

The tombs of Thebes have given us bodies of ancient Egyptians of more than six thousand years ago. At that time the people were characterized by the Grecian type of profile. They resembled the contemporary active peoples in India and Arabia and did not differ much from the Egyptians of our day. The incoming streams of people who settled in the Nile valley, both Asiatic and negroid, changed the appearance of the Egyptians at different times by intermarriage, but when their vigor waned and they were crowded out by other peoples, the Egyptians assumed their regular Semitic characteristics.

Egyptian history really begins with the old kingdom dynasties, about ten thousand years ago. The tombs of Abydos have furnished material for accounts of this early period. There were eight powerful kings in the first dynasty and all of them contributed to the advancement of civilization. Abydos, and later Memphis, were their principal cities. They ruled in great luxury and were patrons of the arts and sciences. The art works, sculptures, and carvings in ivory and ebony of this era speak in eloquent terms of the taste and high mental powers of the people. Modern museums are well supplied with relics of those times, which illustrate the degree of civilization attained by the Egyptians at the beginning of their history better than any written account.

The early Egyptians adopted the sciences, arts and customs of the Babylonians. With these as a basis the priests and learned men experimented and made many independent researches and discoveries.

The pyramids, erected near Cairo 3000 B. C., indicate the high degree of culture which the early Egyptians had attained. These renowned monuments to the kings were scientifically designed and constructed to exist for all time. In order to contribute to their usefulness, they were planned so as to exhibit correct geometrical forms and indicate the cardinal points of the compass and the positions of certain astronomical bodies. The details of their construction disclosed much mathematical, geometrical and physical knowledge, and their actual building called for not only an all-around mechanical skill but a high degree of engineering ability. They were constructed of various materials. Some large granite blocks were used in the outside walls and these were brought from the upper Nile. They were towed down the river on barges and were lifted into the positions in which they are found to-day. Various mortars and mortar mixtures were employed in binding the brickwork and masonry. These called for a good knowledge of chemistry and physics. The arches and sloping walls of some of the larger pyramids show how well the architects and engineers of the day knew their professions. With similar means in their possession, the best professional men of the present day would find it difficult to get such splendid results.

In the past few years, lapidaries and gem-workers have learned to cut stones and gems with steel disk-wheels, the cutting edges of which are furnished with carborundum or emery powder or insets of diamonds. The pyramid builders knew this method of sawing and cutting stones. They actually employed bronze saws set with diamonds to cut the huge blocks of granite, syenite, diorite, and basalt used in the construction of the pyramids. They also set the cutting ends of their rock drills with diamonds, and bored rocks as we do to-day with diamond core drills. The art of making these tools was afterward lost. Only within the past half-century have mechanical rock saws and diamond drills been reinvented. This brilliantly indicates the inventive ability of the engineers at the dawn of Egypt's history. The builders of the splendid monument of Rameses II in the Memnonium, at Thebes, which weighs 887 long tons, transported the huge stone by land from the quarries at E'Sooan, a distance of 138 miles. Such tasks appear never to have deterred early Egyptian engineers and architects. They were so sure of their ability to carry their great operations to satisfactory completion that they never hesitated in agreeing to the severest penalties for nonfulfillment of contract. Their cranes, levers, wedges, rock drills, pumps, air blowers and compressors, and building tools all showed how well mastered was their knowledge.

Their quarrying methods were similar to those used in the best practice to-day. When huge blocks and slabs of stone were needed the required dimensions were marked on the rock and channeled out. Metal wedges were forced into the channels and struck at once by a large number of hammers. The constant vibration, in time, broke off the stone with clean-cut surfaces. When these were to be carved into statuary or ornamental shapes it was often done at the quarries, so as to reduce transportation difficulties. Water transportation was used when possible. When the stone had to be moved over the desert sands it was lifted by cranes and set on sleds drawn by men or animals, or driven forward by levers, just as heavy steel machinery is moved by modern engineers.

The principle of the siphon was known to the Egyptians at an early period. It was employed daily in many homes for supplying water and for drawing off wine from barrels and tanks into domestic utensils. Its principal use, however, was in civil engineering works. Siphons were constructed on a large scale for furnishing water to villages, draining land for farming, and for irrigation purposes. They were built, in many known instances, for carrying large quantities of water, in high lifts, over hills.

Herodotus tells us that the science of geometry was discovered by the Egyptians as a result of the necessity for making annual surveys of the farming lands in the Nile valley.

When geometry was established as a practical science, land and astronomical surveying were simplified and many branches of mathematics were enlarged. The science of marine surveying was also developed and this led to a great improvement in map-making and in geography, in which the Egyptians became famous.

The skill attained by the Egyptians in land surveying required accurate surveying instruments. These were invented at an early period. The Greeks claim the invention of the theodolite and similar instruments, but Egyptian history shows that gnomons, surveying compasses, and levels were used by Egyptian surveyors long before the Greeks began to study the learning of Egypt.

Astronomical science made great progress in Egypt. The theory attributing to the sun the central place in our planetary system, now called the Copernican theory, was known and used in Egypt. They were familiar with the obliquity of the ecliptic, and knew that the Milky Way was an aggregation of numerous stars of various sizes. They understood that moonlight is simply the reflected light of the sun. The movements of comets, the positions of the principal stars and stellar constellations and other astronomical phenomena were studied and charted on astronomical maps or recorded and forecasted in astronomical tables.

The discoveries made by the Greek scientists naturally stimulated philosophical thought, which in turn reacted upon scientific experimentation and led to a broadening of the scope of general research work. We are dependent upon the pictorial records of early Egyptian times for descriptions of the instruments and machinery employed and these are not always clear. They indicate, however, that the Egyptians quickly learned the sciences developed by the Babylonians and other Oriental peoples and improved them. Their knowledge of astronomy, mathematics, geometry, chemistry, physics, medicine, and agriculture was extensive. The priests and learned men taught the pure sciences and constantly experimented; the engineers, architects, surveyors, and mechanics applied the sciences to the arts.

In one of the records of an early dynasty the father of a student sailing up the Nile to begin his studies in one of the leading scientific schools gave this advice: "Put thy heart into learning and love knowledge like a mother, for there is nothing that is so precious as learning."

The Mesopotamian peoples, as we saw in the last chapter, considered the stars and principal heavenly bodies as deities. The Egyptians did not do this, although they looked upon the heavens as the abode of all pious souls. Their astronomical knowledge at the time of the establishment of the New Empire at Thebes, about the year 1320 B. C., was remarkably extensive.

The Egyptians divided time in accordance with the course of the sun into periods of 365¼ days, and these were divided in accordance with the course of the moon into periods of about 29½ days. Thus the basis of the system of years and months used by us was perfectly understood by the Egyptians.

The science of medicine was developed at a very early period in Egyptian history. The various divisions of physicians, surgeons, pharmaceutists, veterinarians, and dentists organized by the Babylonians were retained by the Egyptians. Many names of distinguished practitioners have been handed down. Nevertheless, their anatomical knowledge remained poor, and there were many superstitious practices connected with medicine. The various medical manuals which have been preserved show that the Egyptian physicians studied diagnosis with modern thoroughness. They were aware that an exact knowledge of each disease, obtainable only by a complete study of the symptoms, was necessary before a correct treatment could be prescribed. When the magic and the superstitious dressings are abstracted from Egyptian medical works and prescriptions, we find that the broad principles were sound and efficient. They were developed along lines similar to those of modern times.

Mathematics attracted much attention in Egypt. The learning of Oriental countries on this subject was readily absorbed by the Egyptians. The Greek historians were so surprised at the efficiency of the Egyptians in this branch of knowledge that they almost unanimously asserted that the mathematical sciences originated in Egypt.

The pyramid base lines run in the direction of the four points of the compass, and were determined by correct astronomical methods. The astronomers and surveyors were skilled in trigonometry. Fractions were known to the Egyptians, who were taught in the schools of Babylon. The modern x, representing an unknown factor, was known to the Egyptians under the name of "hau."

Quadratic equations were employed by them. The problem of finding x and y, when x^2 + y^2 = 100 and x:y = 1:¾, one of the earliest problems of this character known, was found in a papyrus at Kahun. The problem was stated as follows: "A given surface of, say, 100 units of area, shall be represented as the sum of two squares, whose sides are to each other as 1:¾."

The papyrus gave the working out of the solution. Many similar problems are given in mathematical works and papyri. They show the proficiency in mathematics that Egyptian scientists had attained at a remote period. But their methods of expressing mathematical problems were crude and, consequently, involved much tedious labor in finding solutions. There can be little doubt that if effective mathematical symbols had been devised the abstract sciences would have made even greater progress than they did in early Egypt. When we study the complicated solutions of algebraic problems made by the Egyptians, owing to the lack of simple symbols, we can appreciate how greatly modern mathematical science is benefited by the devices now employed for expressing quantities, variations, and operations.

The Egyptians were expert in applying the discoveries of science to the arts. The Nile made their country potentially rich in agriculture, and they devoted much attention to inventing such things as single and double plows, rakes, and other agricultural machines, many of which were drawn by oxen, donkeys, and other animals. Reaping was done with sickles and scythes. Not only was irrigation understood and widely practiced, but the importance of fertilization was recognized.

The farmers understood the preservation of meat, vegetables, and foodstuffs generally, by drying or pickling. They also brewed beer and made wines, vegetable and seed oils, and alcohol. The selection of breeding animals and the principles of variation were understood and employed for developing particular breeds of cattle and farm stocks.

The papyrus reed grew luxuriantly in Egypt and this resulted in the discovery of paper making, weaving, thread making and many textile methods. These industries led to the invention of looms, rope and twine twisting appliances, flax weaving and other machinery. The linens and cloths made by these machines have never been excelled.

Dyeing was developed with the textile industries. As the skies of Egypt are bright, the people in all ages have had a fondness for brilliant colors. The call for bright textile colors led to a considerable development in the chemistry of dyes and dyeing. Vegetable and mineral dyes were used. Dyes were not always applied to the whole pieces of goods, but stenciling and other methods of patterning were used. The highly organized artistic skill of the people demanded art-designed textiles and the manufacturers responded with beautiful and rich materials.

The fur and feather industries became important at an early period. The Egyptians were fond of beautiful ornamental skins like those of the panther or gazelle. Such skins were manufactured into numerous domestic articles, made into clothing or used as rugs, mats, and seat coverings.

Skins not valuable for art purposes were sent to the tanners to be converted into various kinds of leather. Tanning was highly developed, and the tanners turned out leathers which are to-day admired for their excellence. The tanners carried on their industries by chemical processes similar to those in use to-day.

The scarcity of wood in Egypt led to the invention of various substitutes. One common substitute was a kind of papier mâché. This was manufactured out of linen, wood or vegetable pulp and various kinds of paste. When it was used for art work the molded forms were covered with lacquer or various kinds of stucco. Very beautiful objects were manufactured from these substances, which indicate that the artists possessed a wide practical knowledge of physical and chemical principles.

Chemical knowledge was also well shown in their manufacture of glass. They excelled in this industry. All kinds of glass were made and decorated by staining and glazing. The glassmakers were able to imitate precious stones in glass and their glass-bead and enamel work has never been excelled. Some modern chemists express the opinion that glass making was carried to a greater degree of perfection in Egypt than any modern nation has attained.

Egyptian porcelains were also finely executed. These were enameled, stained, and decorated in numerous ways. The colors, glazes, and art mediums employed by the artists in pottery and porcelain necessitated a wide chemical knowledge. Some of the pigments employed both in glass and porcelain ornamentation were made from metals. Their use required a knowledge of metallurgy. Metals like lead, nickel, manganese required fluxing and refining before they could be secured in a state sufficiently pure to be used as bases for colors. Not only did the artists know the value of many metallic oxides, but they understood how to secure the tints resulting from blending different oxides, and by acting upon metals with acids, just as they acted upon vegetable and metallic dyes with acids to get rare tones in linen dyeing.

Mordants were employed in dyeing cloths and these were acted upon by acids and alkalies to produce various colors. We are dependent upon the relics which have been preserved for our knowledge of the chemical and physical learning of the Egyptians. No chemical books of theirs have come down to us, and inferences must be drawn from the results seen.

In carrying out metallurgical operations, the Egyptians employed small blast furnaces and melting pots. Air was compressed by bellows and conducted into molten substances by pipes.

The methods of metal working, melting, rolling, forging, soldering, annealing, and chasing were similar to common methods in use in modern times.

The Egyptians were a practical people. They made wonderful progress in the industrial arts and learned enough of scientific principles to enable them to deal with much success with the mechanical, agricultural, astronomical, medicinal, and chemical problems encountered. But, like the Babylonians, Assyrians and other Oriental peoples, the Egyptians did not systematize their sciences. Their investigations were always carried out with practical objects in view, and when the objects were attained the experiments ceased. They never discovered a true scientific method. That was left to be done by another people who were long students of Egyptian science and who, taking all the learning of Egypt, worked out from it, as a basis, the principal sciences as we have them to-day. The Greeks took the torch of scientific progress from the Egyptians, organized learning, and passed it on to the Romans and other peoples in sound, effective and augmented forms.

The Greeks idealized and systematized scientific principles, whereas the Egyptians and earlier peoples rested content with the results they could obtain by their practical efforts. We will find that, throughout the history of science, progress has always been made by similar reactions between peoples possessing the one a practical, the other a philosophical genius.

CHAPTER V
FOUNDING OF SYSTEMATIC SCIENCE IN GREECE

The world is indebted to the Greeks as much for science as for art and literature. The idealistic spirit of ancient Greece invested scientists as well as poets, artists, and thinkers generally. But the Greek scientists were students in the great schools of Egypt and brought much of their knowledge from that country. The greatest contributions made by Greece were in the nature of methods and analysis. They were led to these by the tendencies of the Greek mind to abstract thought and philosophical investigations. They soon recognized that science is knowledge gained by certain methods of abstraction. Data had to be systematically collected, digested, classified, and impartially studied. The results of such studies had to be assembled and expressed in the most useful forms. Progress had to be made by the trial and error method and the results of experiments tested by synthesis as well as analysis; by induction as well as deduction.

The Ionian philosophers were the first to break away from the mythological traditions surrounding the principles of Egyptian and Asiatic science. Thales of Miletus about the year 580 B. C. taught that there is an essence, force, or soul in all things. This universal principle of activity is superhuman. Seeking to find of what the world is made, he arrived at the idea that water, or moisture, is the basic element. All matter, he said, is water in various forms and combinations. Here we see scientific knowledge sought with a definite aim and with unity of purpose. None of the earlier peoples had ever attempted to approach knowledge in this logical and fruitful manner.

When the learned Babylonians were asked what the earth was they simply said: "When the world was created, Marduk, the sun god, took Tiamat, or Chaos, and divided her. The sky was formed above and the earth below." And the Egyptians answered the question in a similar way by saying: "When the world was created, Shu tore the goddess Nuit from the arms of Keb, and now she hangs above him and he is the earth."

It was this kind of statement that Thales cast aside. He sought for more concrete definitions. Customary beliefs were not acceptable to him; his knowledge must be based on reason. Here we see the dawn of a new scientific spirit and the beginning of a new method of investigating knowledge. The world was introduced to a new field of intellectual activities.

The theory of Thales was studied by other Greek philosophers. But Anaximander, a friend of Thales, rejected it, and in its place suggested that there is one eternal, indestructible substance which constitutes the basis of matter. This was not water but an infinite eternal motion. Water is subjected to extremes of temperature. Under such conditions nothing could have been stable enough to constitute matter. A primary substance must be free from warring or antagonistic elements.

The world arose, said Anaximander, through the evolution of a substance subjected to temperature changes which developed from the eternal, boundless, basic element. A sphere of flame arose from this, as from an explosion, and assumed a rounded form with concentric divisions. As these rings became detached, the sun, moon, stars, and other heavenly bodies and the earth were formed. Aristotle tells us that, according to Anaximander's theory, the terrestrial region was at first moist; and, as the moisture was dried up by the sun, the portion that was evaporated produced the winds and the turnings of the sun and moon, the remaining portion becoming the sea. In time the sea, Anaximander held, would dry up. The heat, or fire, of the world would burn the whole of the cold moist element. Then the world would become a mixture of heat and cold like the boundless, primary element surrounding it, and by which it would be absorbed.

This theory of matter and the evolution of the world marks a notable advance over any previous scientific theory. It was well developed by numerous teachers of the Milesian philosophical school and has played a great rôle in intellectual history.

The daring nature of some of Anaximander's explanations of earthly organisms may be realized from a sketch of his views on the evolution of animals. He taught that living creatures arose from the moist element as it was evaporated by the sun. Man at first resembled a fish. All animals were developed in the moisture wrapped in a protecting cover or bark. As they advanced in age, they came out into a drier atmosphere and discarded their protective coats. Man was not an original creation, but resulted from the fusion of other species. Anaximander's reason for this statement was that the period of infancy of the human being is so long that had he been born that way originally he could not have survived. There must have been a slow development from ancient ancestors. This may be regarded as an anticipation of the Darwinian theory. Thus man's thoughts in succeeding ages have a rhythmic swing.

Anaximenes rejected some of Anaximander's ideas and furnished new ones to take their places. He was not so daring a thinker as his predecessor, and his theory of the world was not as interesting as Anaximander's. Many of his teachings, however, are accepted as sound to-day.

Anaximenes contended that the basic element was not boundless, but determinate. Innumerable substances are derivable from it and, just as our soul, like an atmosphere, holds us together, so do breath and air encompass the whole world. Air is always in motion, otherwise so many changes could not be made by it. It differs in various substances in virtue of its rarefaction and condensation.

The perpetual changes taking place in the world owing to the instability of matter were emphasized by Heraclitus. He taught that there is nothing immutable in the world process excepting the law or principle which governs it.

Cosmological speculations were not the only ones attracting the attention of the Greek scientists. Pythagoras, for example, founded a philosophical college devoted to mathematical studies which resulted in the development of arithmetic to points beyond the requirements of commerce. He made arithmetic the basis of a profound philosophical system.

Pythagoras studied science in Egypt and first became familiar with Egyptian and Babylonian mathematics and geometry. He also studied the Milesian cosmological philosophy. On his return to Greece from his foreign studies he sought to discover a principle of homogeneity in the universe more acceptable than any suggested by the earlier philosophers. He had noticed numerous relationships between numbers and natural phenomena, and believed that the true basis of philosophy was to be found in numbers. In seeking data to sustain this thesis, he discovered harmonic progression. His experiments showed that when harp strings of equal length were stretched by weights having the proportion of ½:⅔:¾, they produced harmonic intervals of an octave, a fifth and a fourth apart. Since he saw that harmony of sounds depended upon proportion he concluded that order and beauty in the world originate in numbers. There are seven intervals in a musical scale, and seven planets sweeping the heavens. Seven must, therefore, be a basic number. This suggested to him his ideas regarding the harmony of the spheres.

Pythagoras and his students found that the sum of a series of odd numbers from 1 to 2n+1 was always a complete square. When even numbers are added to the above series we get 2, 6, 12, 20, etc., in which every member can be broken into two factors differing from each other by unity. Thus 6 = 2.3, 12 = 3.4, 20 = 4.5, etc. Such numbers were called heteromecic. Numbers like n(n+1)/2 were called triangular. A large number of other arithmetical relations were found and given distinctive names. The Pythagoreans were also familiar with the principles of arithmetical, geometrical, harmonic, and musical proportion.

DE WITT CLINTON TRAIN OF 1831 BESIDE A MODERN LOCOMOTIVE

LOCOMOTIVE OF THE 1870 PERIOD STILL IN USE IN THE OZARKS

"JOHN BULL," A LOCOMOTIVE BROUGHT FROM ENGLAND AND PUT INTO SERVICE IN AMERICA IN 1831

Pythagoras made similar advances in geometry. He believed that each arithmetical fact had an analogue in geometry, and each geometrical fact a counterpart in arithmetic. He devised a rule by which integral numbers could be found so that the sum of the squares of two of them equaled the square of the third. He also developed the theory of irrational quantities. The first incommensurable ratio discovered is said to have been that of the side of a square to its diagonal which is 1:√2̅.

Euclid (300 B. C.) developed this theory in the tenth book of his geometry as still used.

Pythagoras not only placed mathematics on a solid scientific basis, he also established the fact that the physical phenomena of the world are governed by mathematical laws.

Little progress appears to have been made in astronomy by the Greeks in the time of Pythagoras. The Milesians and the associates of Pythagoras advanced numerous theories, but none of these was better than some of the Egyptian ideas. Hicetas, and others of this period, believed that the sun, moon, stars, and all other bodies in the heavens were stationary and that only the earth moved. The great turning movement of the earth around its axis produced the illusion that it was the heavenly bodies which were moving while the earth remained stationary.

The astronomical theories of Pythagoras, Hicetas, and Philolaus, all affirmed that the universe is composed of the elements earth, air, fire, and water, the whole mass being of spherical shape with the earth at the center and all having life or motion. These early theories, 2,000 years later, did service by aiding to secure acceptance for the Copernican theory. The Pythagorean ideas that the universe is one grand harmonious system, and that thought instead of sense is the sole criterion of truth, have exercised important influence on intellectual speculation throughout the ages.

In order to collect data for testing their theories in the physical and mathematical sciences, the Greeks invented many physical appliances. The monochord, employed in determining the relationships of vibrating harmonic strings is one of the first mechanisms used in practical physics that we have definite information about. An anvil, metal and glass disks, and bell-shaped cylinders were employed in studying the movements of sound waves.

Alcmæon (508 B. C.) was one of the earliest of the Greek anatomists. He was a disciple of Pythagoras and employed the logical research methods of his teacher in the investigation of medical problems. Although the Egyptians had developed medical science to a considerable extent and had taught the Greeks, their methods were not based upon sound principles. The result was that the more analytically minded Greeks could not accept certain Egyptian ideas. The Egyptian anatomical teachings were particularly crude, and Alcmæon began to investigate that science. His discoveries, both in anatomy and physiology, were very great. He outlined the functions of the principal organs of the body, discovered the optic nerve, the difference between the arterial and nervous systems, the Eustachian tube, the two divisions of the brain, the nerves connecting the brain with the organs of sense and with the spinal column. These advances placed the medical sciences on a logical basis similar to that of the physical, mathematical, and astronomical sciences. This first great anatomist and physiologist invented the practice of anatomical dissection and surgical exploration, and advanced the practice of medicine to a higher degree of usefulness.

After the Greeks had satisfied themselves that they possessed a cosmological theory which answered the demands of reason they turned their investigations to the question of how matter was changed into its innumerable forms. Empedocles had taught that when the primary elements, earth, air, fire, and water, were mixed in variable proportions they yielded different kinds of matter. Leucippus, Democritus, Anaxagoras, and others studied the subject more carefully and developed a novel theory. When matter is divided as far as possible do the ratios of the constituents remain the same? This problem attracted their attention. They also asked themselves whether there was not a simpler conception to explain the basic state of matter. When they began their inquiries, the qualities of matter were believed to reflect their essences. For example, the sweetness of honey and the color of the sky were real things which should be studied in themselves apart from honey and the sky. Democritus thought, however, that such changes of color as the sky undergoes at dawn and sunset would not take place if the colors were real elementary things. While meditating on this the thought arose in their mind: "If we assume matter to be composed of an infinite number of minutest particles or atoms, could we not explain the changes in matter by changes in atomic quantities and orders?" This line of thought resulted in the development of the atomic theory and the origin of the philosophic school of the atomists.

According to Leucippus some of the atoms darting about in the universe collide and thus give rise to new substances. He also believed that the atoms followed whirling or circular paths and that such rotary motions drew in neighboring atoms, and that as these movements continued indefinitely within the atoms the constituents were being constantly rearranged, the lighter elements being grouped around the periphery; the heavier ones around the center. These changes were due to pressure and impact. These conceptions about atoms were carried into cosmological discussions and it was taught that there are various worlds and planets within the boundless universe, each one moving freely according to physical laws, unless fractured by collision with another.

Zeno challenged these doctrines because of the importance attached to the whirling motion. He attempted to show that such atomic motions are impossible. His proofs of the impossibility of atomic motion were designed with the object of sustaining his own theory of an ultimate principle of unity. His mental trend was toward negation. Whenever his rival Parmenides argued affirmatively regarding a scientific principle, Zeno would invariably maintain the negative side of the question.

Zeno's first proof of the impossibility of motion referred to the impossibility of passing through a fixed space. He showed that by dividing a line into an infinite number of parts an infinite number of points would be obtained and these permitted no beginning of motion.

His second proof tried to show the impossibility of passing through space having movable boundaries. The story of Achilles and the tortoise illustrates this. A pursuer in a race at every interval must reach a point from which the pursued starts simultaneously. But the latter is always in advance.

The third, or "resting arrow," argument showed that a moving arrow is at every instant in some one point of its track. Its movement at such instant is then equal to zero. Its track is a group of zeros. No magnitude could be framed from these.

Zeno also anticipated much later philosophical discussions, like Einstein's, relating to the relativity of motion. He took for an example a moving wagon. Its movement would appear different to observers on other moving bodies going in various directions. They would see changes in rates of speed as well as in direction.

Protagoras, at a subsequent date, developed this idea of relativity and showed that things are as they appear to each individual at the moment they are perceived. He summarized his teaching in the aphorism: Man is the measure of all things.

The Skeptics, 200 years later, developed the Protagorean theory of relativity, and by a series of arguments attempted to prove that perceptions change not only with the different species of animate beings, but with many conditions and circumstances. It was also shown that not only man's perceptions are subject to changes, but also his opinions following from his perceptions. Another school taught that to every opinion the opposite can be opposed with equally good reasons.

CHAPTER VI
GOLDEN AGE OF GREEK SCIENCES

Science had made a great advance as a result of the researches and theories of the atomists. A consistent mechanical theory of matter and the universe had been set forth. Science and philosophy were stripped of many of the old superstitions that had clung to them. The leading theories invented were based on logical principles. While these changes were being worked out, numerous inventions of scientific instruments and apparatus were made and systematic methods of studying science were organized. These furnished the means for still greater progress.

The apparent completeness of the mechanical theory of the universe satisfied the inquiring intellect. The excitement caused by the scientific discussions and discoveries from the time of Heraclitus subsided. But after a short intervening period, when public attention had been largely centered on practical affairs, there was a reaction against science. When scientific principles were quoted a tendency was shown to question their validity and usefulness. This resulted in inquiries into the sources of knowledge and conduct and ushered in a new intellectual era that is now known as the Humanistic period which, beginning about 450 B. C., extended to 400 B. C.

The Sophists, who were teachers of rhetoric and were accustomed to studying the phrasing of verbal statements, became active in searching for the foundations of thought.

The Protagorean theory of knowledge was based on Empedocles's doctrine that the inner atoms advance to meet the outer ones. Perception is the resultant product of these atoms when they collide. They believed that this perception is something else than the perceiving subject and is also something different from the object giving birth to the perception. It is conditioned by both, but has a distinct existence. The doctrine of the subjectivity of sense perception was developed in explanation of this psychological problem. From this it followed that knowledge must be strictly personal and could be true only under conditions existing at the instant of perception. These limitations caused Protagoras to advance his theory of relativity, which teaches that man is the measure of all things. Facts are what appear to each individual to be statements of truth. Isocrates, Plato, Aristotle, and Socrates were the leaders of this intellectual movement.

Socrates developed the Pythagorean theory of intelligible forms. The specific qualities of the senses belong to the realm of perception. When these are withdrawn from an object of thought there remains only the form or idea. Therefore it is evident that pure, intelligible forms constitute the essences of things. The early scientists, such as Democritus, thought, perhaps, in terms of atom forms. Socrates, Plato, and later teachers looked upon forms as conceptions of similar logical elements. Knowledge, in the view of Democritus, was essentially rationalistic. Plato considered knowledge as having ethical and æsthetic purposes within itself.

Each of these types of rationalism stimulated Greek thought and resulted in a strong impulse to philosophical and scientific investigation. They prepared the outlook for Aristotle.

Science had been hampered by the confusion raised by the discussions relating to forms. Aristotle realized that proper progress in logic, physics, and ethics, the leading sciences of his time, could not be made unless the essential nature of science were kept in view. He saw that knowledge of the forms of correct thinking can be understood only by keeping in view the object of thought and this requires definite ideas of the general relations of knowledge and its objects. The study of general relationships led to the study of particular or special relations. The connection of general with particular ideas was unfolded, and Aristotle saw that conceiving, understanding, and proving result from the deduction of particular from universal, or general, ideas. Therefore science consists in deriving or deducing facts acquired through perception from their general grounds or phenomena. The logical form of the syllogism naturally suggested itself to Aristotle when engaged with these thoughts and the invention of the syllogism was one of the most brilliant contributions to knowledge made by the Greeks.

The logical results of the invention of syllogistic forms suggested a solution of the problem of true reality which Aristotle showed was the essence that unfolds in phenomena themselves. This led to fruitful scientific results. Plato and his contemporaries unified mathematics, formulated the definitions logically, and demonstrated correct methods of criticism and proof. A point was shown to be the boundary of a line; while a line is the boundary of a surface, and a surface the boundary of a solid. This concrete definition of scientific elements progressed through the use of analytic methods, by proceeding from the known to the unknown, and led to the discovery of tests for scientific assumptions and of synthetic proof. None of the earlier philosophers possessed anything like the progressive tools Aristotle placed in the hands of scientists. Their use quickly led to a general review of knowledge and a great increase in the number of sciences.

The textbook on geometry compiled by Euclid, still used in many schools, gives us a good picture of the state of scientific methods in his time. Euclid, like Aristotle, Plato, Socrates and others, was a great systematizer. He collected the geometrical proofs of his mathematical predecessors, selected those which were logically correct and simple, and raised on a few axioms, or first principles, a great geometrical system.

Archimedes published textbooks on spherical and cylindrical geometry. He proved that the surface of a sphere is equal to four times a great circle. He showed the properties of spherical segments and methods for calculating surface areas and other parts of spherical forms.

This great scientist also developed mechanics and physics. He investigated the lever and demonstrated the principle upon which its power is based. He then studied hydrostatics and hydraulics, and discovered the theory of specific gravity and invented methods for determining it.

Apollonius began publishing scientific textbooks about forty years after Archimedes. His masterpiece was his textbook on conic sections.

The work done by Archimedes on the quadrature of curvilinear figures resulted, centuries later, in the discovery of the infinitesimal calculus, while the theory of conic sections published by Apollonius led to theories for the solution of problems relating to geometrical curves of all degrees. They placed the geometry of measurements and the geometry of forms and positions on strictly scientific bases.

Hipparchus applied the new mathematical and geometrical discoveries to astronomy. He found a method for representing the observed motions of the sun, moon, and planets by assumed uniform circular motions. His theory of the sun's motion assumed that the earth was not the center of the sun's orbit. He drew a line through the earth and the real center of the orbit and found where the sun's distance is least and where greatest. He then compiled a large set of solar tables giving the position of the sun among the stars at any time. He next turned his attention to the movements of the moon and prepared tables for determining eclipses.

Then the various planets were studied and their mean motions were calculated and recorded. The stars were mapped and catalogued. He described the apparent movements of 1,080 stars and comparing his observations and calculations with those of Aristyllus and Timocharis, made 150 years previously. He also discovered the precession of the equinoxes.

The astronomical calculations of Hipparchus led to a great improvement in trigonometrical methods. By using chords, as we use sines, and assuming the heavens to be a plane surface, he fixed the positions of stars (and similarly geographical points) by the intersections of lines of latitude and longitude.

A planosphere, an instrument for representing the mechanism of the heavens, was among the many scientific inventions of Hipparchus.

While Hipparchus was engaged upon problems in astronomical physics, Hero, a professor of science at Alexandria, was working out numerous problems relating to matter and devising machines for practically applying the teachings of mechanical science. Ctesibius, assisted perhaps by his pupil Hero, made a large number of valuable engineering inventions. He was an authority on hydraulics and pneumatics. He devised improved siphons, a pneumatic organ, a force pump, a vacuum pump, a hot-air motor, and other machines.

His studies regarding the physics of gases led him to adopt a molecular theory of matter. He believed that there are vacua existing between the innumerable particles which constitute matter in all its states and forms.

Ctesibius improved surveying instruments. His dioptra, an instrument corresponding to a theodolite, was a plane table set on a tripod, furnished with compass points and two sights. The plane was adjusted by screws and a water level. This instrument was used by engineers for leveling, laying out irrigation works and farm lands, sinking shafts for mining and prospecting purposes, and for tunneling. A cyclometer for measuring angles of dip and elevation of rock beds and mountains was also used with this instrument.

The Greeks owed much of their knowledge of hydrostatics, mechanics, pneumatics, and physics generally to Ctesibius. He was not only a great inventor and lecturer, but also a writer of valuable textbooks dealing with physical and mechanical sciences.

Hero edited a number of editions of the textbooks of Ctesibius, and is credited with inventing some of the theories and machines discussed. He, too, published numerous scientific books.

Hero's work in trigonometry was important. He described a formula for estimating the area of a triangle which still bears his name. He defined spherical triangles and arranged methods for determining the volumes of irregular solids by measuring the water displaced by them.

The steam turbine is the best known of Hero's machines. Scholars read much about his wonderful musical instruments operated automatically by pneumatic means resembling the mechanisms of player-pianos, and particularly about his mechanical toy mimicking a number of singing birds. A group of birds were made alternately to sing and to whistle. The mechanism consisted of air tubes operating various kinds of whistles. A running stream was made to operate an air compressor. The air from the compressor tank operated the various movements of the birds and supplied air for blowing the whistles. The numerous mechanisms of this character which Hero and his master made indicate that they were as much at home in making pneumatic and similar mechanical toys as is any expert to-day. They not only knew the scientific principles, but had the engineering and mechanical ability to design them and make them work.

Hero's fire engine is not as well known as his steam engine. It was a remarkable invention, however. It was worked by levers and force pumps and resembled the engines still employed by fire companies in some remote rural districts.

Not the least interesting machine described by Hero was his slot machine for dispensing wine and other liquids. This machine consisted of a cylindrical container with a slot hole on top through which coins were dropped. Beneath this there was a lever with a receptacle for the dropped coin. The weight of a falling coin depressed one arm of the lever and raised the other, which opened a valve and allowed the liquid to escape. When the lever arm had moved a certain distance, the coin slipped off and the valve was automatically closed.

Hero's steam turbine was a crude model. Steam was generated in a boiler and conducted through pipes so as to play upon revolving globes or wheel vanes. This machine was invented to operate mechanical toys. It was not until nearly 2,000 years later that it occurred to an inventor that steam could be used to operate more important mechanism than toys.

The next great name in science is that of Claudius Ptolemy, an Egyptian astronomer, who lived in Alexandria about 139 A. D. He brought out new editions of the mathematical works of Hipparchus, and published a number of scientific books of his own. His principal work, known as the Grammar of Mathematics, formed the basis of all astronomical studies down to the time of Copernicus, about 1500 A. D.

The earth formed the center of the universe, according to Ptolemy's theory. The sun and planets, he thought, revolved around the earth.

We obtain our minutes and seconds from Ptolemy's great work. He divided the circle with 360 degrees and its diameter into 120 divisions. Each division of the circumference he divided into sixty parts. The Latin names for these parts were partes minutæ primæ and secundæ, or the first small divisions and the second small divisions.

The Greek scientists were so interested in logical analysis that they constantly investigated the fundamental facts upon which their teachings were based. They made provisional hypotheses, deduced mathematical consequences, and compared these with the results of observation and experiments. When Hipparchus found that his planetary theories did not meet his tests, he decided to make as many new observations as possible and collect astronomical data to be used at a later period by other scientists. He realized that, while he knew the old theories were incorrect, there was not enough data at hand to enable better theories to be established. He therefore deliberately labored to provide data for posterity.

Ptolemy's treatise on geography was an encyclopedia of places, names, and descriptions. In this work he located over 5,000 places between India and Morocco, giving their latitude and longitude.

Ptolemy's textbooks on sound and optics were long celebrated. The work on optics contained valuable chapters on refraction, a subject he had done much to develop. These works contained some of the finest collections of experimental data illustrating the best scientific methods used in antiquity.

The next great mathematicians and physicists are Pappus and Diophantus. The former lived about 300 A. D. He was the author of textbooks on mathematics and astronomy. Some of these have been preserved and are of great value in exhibiting the status of Greek science at that time.

The arithmetical textbook of Diophantus, which is extant, is remarkable as being the first to contain a complete exposition of algebra and the use of algebraic symbols and methods. Euclid solved quadratic equations geometrically and Hero solved them algebraically, although without using symbols. But in Diophantus's arithmetic quadratics are solved by the use of algebraic symbols. After several centuries, when the Euclidean geometry was in the ascendant, and many problems which were suited to arithmetical and algebraic methods of analysis were solved by geometrical and trigonometrical means, Diophantus succeeded in renewing interest in arithmetic and mathematics generally.

Political changes and other intellectual interests soon after the time of Diophantus turned men's thoughts in other directions and no great scientists were afterward developed by the Greeks.

While the physicists were making their discoveries, medical men were studying anatomy, biology, and materia medica. Medical science in the time of Diophantus had a status, with a theory and practice, closely resembling those of to-day.

Hippocrates of Cos (460 B. C.), was the greatest leader of Greek medical science. He cast superstition aside and based his researches and practice upon the same principles of inductive philosophy that had proved so valuable in other sciences. He established hospitals for the nursing of the sick, and had attendants note the symptoms and the histories of the cases. In this way a number of casebooks were made. He wrote a work on Public Health. His operations in trepanning were more heroic than would be undertaken by good surgeons to-day. These are described in his book on Injuries of the Head. Many of his works are extant and furnish very interesting and valuable pictures of the state of medical science in Greece.

During the several centuries in which the Greeks placed science and all the leading departments of knowledge upon firm bases, stripped of the sentimental and traditional trappings which had come down from remote times, changes of a political nature were causing the immigration of foreign peoples to Greece. The importance of preserving racial purity was not recognized. The result was that the original Greeks, who were of the long-headed type, were forced to give way to the hordes of inferior peoples coming in from Asia. These new, round-headed people were not original thinkers, and were unable to advance science and the arts as the Greeks had done. They were, to a large extent, even unable to appreciate the wonderful treasures of knowledge bestowed upon them by the cultured people they had displaced.

The Egyptians and Babylonians advanced knowledge for practical purposes and when these were served they showed no desire to explore further. But the analytical mind of the Greek called for knowledge of basic laws and first principles.

CHAPTER VII
THE ROMAN AND MIDDLE AGES

The Romans succeeded to Greek culture; but they were a business people. They exhibited smaller intellectual capacity than the Greeks for analytical thinking. This precluded them from advancing the sciences. The Romans attained great eminence in oratory, history, art, and literature. They probably equaled the Greeks in music. They never produced any great thinkers like Aristarchus, Hipparchus, Euclid, Ptolemy, Archimedes, Democritus, Hippocrates, Plato, Aristotle, and others referred to in the preceding chapters.

What the Romans lacked in intellect they made up in energy. They became good soldiers and sailors, good politicians, able architects, engineers, and farmers. This explains how they became so powerful politically. They were the most practical people in a practical world. Instead of bequeathing us great scientific masterpieces like the Greeks, they have left us miles of useful roads, waterways, walls, fortresses, bridges, buildings, and statuary. Remains of these objects occur throughout Europe and northern Africa, showing that Roman engineering practice has been as universally useful as Roman law and political practices. The great scientific discoveries of the world have been made by only a few peoples. Those nations which have possessed the scientific temperament have not always been productive. Great inventions and discoveries appear to be made in response to national needs and are preceded by long periods during which the preparatory work is being done. The great men of science being active generalizes, need the cooperation of many lesser scientists to collect data and observations upon which general theories may be built. This appears to be the explanation of the irregular periods of great scientific activity.

Julius Cæsar, great in many departments of human endeavor, carried through two important scientific reforms. He caused the rectification of the calendar. In the year 47 B. C. there was an accumulated error of nearly 85 days in the calendar. This was corrected and the year was made to consist of 365 days, with an additional day every four years. Cæsar's calendar is still in use.

His other reform, which was not completed until the reign of Augustus, was a scientific survey of the Roman empire. This conferred great benefits not only upon Rome, but upon the world. Geography, commerce, and industry were enlarged, many practical scientists were trained, and the various data and maps which had to be collected and drawn resulted in many improvements in statistical methods and in surveying and astronomical computations.

An early contribution to science by Rome was the textbook on Architecture by Vitruvius. This great work became the standard guide to building until the changed conditions in the Middle Ages called for new architectural methods.

The works on natural philosophy by Lucretius, the geography of Strabo, the books on natural history by Pliny, and the encyclopedic medical works of Galen were successive contributions. These chiefly aimed at developing the teachings of the great Greek scientists for the practical use of the Romans.

Roman history shows that all branches of the learned professions were popular and Roman professional men were very competent. None, however, stands out as a great discoverer. The names just above recorded are those of the chief lights of Roman science, and they simply reflect the practical nature of the Roman intellect. The best the Romans did was to preserve Greek science, test it extensively by practical applications throughout their vast empire, and hand it on to succeeding nations.

Philosophical thought in the declining years of Greece turned to theosophical speculations, and finally to ethics and theology. Much interest was evinced by the Romans in ethics, æsthetics, and theology. A new religion, destined to exert profound influences on intellectual developments, gradually attracted the attention of thinkers. The Romans were fascinated by the monotheism of Christianity and the doctrines of a future life and good will and love. There grew out of the critical attacks on this new theology a powerful scholastic philosophy aiming at the exposition, systematization, and demonstration of the principal Christian doctrines.

Aurelius Augustinus, a native of Africa (353-430 A. D.), championed the opinion that knowledge of God and self was the proper kind to study. The sciences have only value in illuminating the power of God. Intelligence is necessary to comprehend what we believe; faith is required to believe what we comprehend. As the highest good, or moral ideal, is transcendent, Christians cannot realize it, so human perfection should consist in the love of God and bearing good will to others.

The conditions brought about by this turn of thought were not favorable for scientific development. The world had to wait until the scholastic philosophy lost itself in metaphysical discussions. Then Roger Bacon (1214-1294) released science and mathematics from the chains which had so long confined them.

While European thought was occupied in discussing scholastic philosophy, the Arabs and Moors were carrying on the practice of the sciences. The Moors in Spain published many valuable textbooks and developed new principles in architecture and medicine. Their Giralda observatory in Seville was the first astronomical building erected in Europe, and their university in Cordova remained for a long period the leading professional school.

The universities of Paris, Salerno, Oxford, and Cambridge, and the law school at Bologna, were founded in the eleventh and twelfth centuries and have continued to hold up the torch of science until our time.

Roger Bacon, an English Franciscan monk, was a graduate of the University of Paris. He was a brilliant student of physical and mathematical sciences. Pope Clement IV invited him to write a textbook of science. Bacon did this in 1266. He became a professor in Oxford University in 1268. His Opus Majus (1267) summarized ancient and current philosophy and science and included the researches of the Moors. This great book reasserted the fact that science must be based upon experiments and that the astronomical and physical sciences must rest upon geometry and mathematics. Bacon's clear recognition of the value of experimental methods and logical exposition mark him as the greatest intellectual force of his century.

The errors in the calendar were estimated and corrected by Bacon. He criticized the astronomical principles of Ptolemy, which were still generally accepted. His experiments in physics led him to make important discoveries in optics. He improved lenses and apparently made microscopes and telescopes. He proposed a lunar theory in accounting for the movements of the tides.

Roger Bacon made so many accurate comments on physical phenomena and so accurately forecasted recent mechanical inventions that his book, which was so far in advance of his time that it was unintelligible and caused him to be charged with witchcraft, still astonishes its readers.

Lenses were used for spectacles in Asia in the remotest times, but there are reasons for believing that Bacon was the first to prescribe them on scientific principles for the correction of defective vision. He also appears to have appreciated the value of gunpowder as an explosive agent and had it introduced into Europe from Morocco. Being misunderstood, Bacon founded no school and left no students.

Nicole Oresme, Bishop of Normandy (1323-1382), used fractional powers in mathematics and developed a notation. About the same period, Thomas Bradwardine, Archbishop of Canterbury, wrote on star polygons, and other Englishmen, like Boethius and Bath, wrote new textbooks on astronomy and mathematics. They started a school of trigonometry in England that made great improvements in that branch of science.

Between 1200 and 1400 A. D. the magnetic compass was improved and used at sea, clocks were improved and made popular, improvements were made in weaving, printing was invented, textbooks were written on many subjects, and education began to spread in Europe. All these factors prepared the way for a great industrial and scientific awakening.

Nicholas de Cusa (1401-1464), Bishop of Brixen, published books on mathematics and suggested that the earth's movements indicate a diurnal rotation.

The way was now paved for a new theory of planetary motions. Nicolaus Copernicus (1473-1543) a Pole, developed the astronomical system bearing his name, as a result of suggestions gained by studying the works of the Greek astronomer Hicetas, and Plutarch's Lives of Greek Scientists. His great work was entitled "De Revolutionibus Orbium Celestium, or the Movements of Heavenly Bodies," which treated the sun as the center of the planetary system.

Weather forecasting was improved by Tycho Brahe (1546-1601), and many fine astronomical observations were made by him. He greatly improved astronomical instruments and built and splendidly equipped a great observatory in Uraniborg, Denmark. Numerous important observations were made there.

John Kepler, the discoverer of the ellipticity of the planetary orbits and the laws of their movements, was a student under Brahe, and continued his master's researches. His observations on the movements of the planet Mars led to his discovery that the planets travel in ellipses and not in circles. Besides his numerous works on astronomy he wrote valuable books on optics and other scientific subjects.

Galileo (1564-1642) took up the work of Tycho Brahe and Kepler and carried it forward to new triumphs. He made the first telescope ever used for astronomical observation, and with it was able to discern that the Milky Way was composed of aggregations of innumerable stars; that the surface of the moon was covered with plains and mountains, that there were four moons revolving around the planet Jupiter, that the planet Venus showed phases like those of the moon as she moved around her orbit, and that there were black spots, at times, upon the sun, which revealed its rotation on its axis. Galileo did equally fundamental work in developing the laws of motion, and the principles of mechanism and physics.

The development of modern mathematics began with three intellectual feats—the invention of the Arabic notation, of decimal fractions, and of logarithms. The notation was derived by the Arabs from India about 700 A. D. They had used numerals long before, but the old system was crude like the systems employed by the Egyptians and Greeks. The Textbook on Mathematics by Mohammed ibn Musa, published at Bagdad about 825 A. D., contained the first notable exposition of modern numerals. This important work gave rise to many more Arabic treatises, some of which showed improved methods.

Decimal fractions were used by the early peoples of central Asia and were transmitted by them to the Babylonians. Their system was based, apparently, upon a sexagesimal scale. Simon Stevin (1548-1620), a Belgian, made great improvements in decimals. He adopted the plan of William Buckley, of England, and other mathematicians, and made the base 100,000, instead of 60.

John Napier (1550-1617), a Scottish nobleman, invented logarithms. The story of this great mathematician's work is one of the most interesting in the history of science. Napier's first table of logarithms was published in 1614. Henry Briggs (1556-1631), professor at Oxford, made suggestions for the improvement of the tables, and persuaded Napier to make the base 10, as is now done in tables of common logarithms. Briggs published tables in 1624 containing the logarithms to 14 places of decimals for the numbers between 1 and 20,000 and from 90,000 to 100,000. Adrian Vlacq (1600-1667), a Dutchman, computed the logarithms of the numbers running from 20,000 to 90,000, and thus completed the whole series of logarithms between 1 and 100,000. Edmund Gunter (1581-1626), of London, calculated the logarithmic sines and tangents of angles for every minute to seven places. He invented the terms cosine and cotangent and used them in a work published in 1620.

Another Englishman, William Oughtred (1574-1660), wrote textbooks on mathematics, and invented numerous mathematical symbols which are now in general use, as well as rectilinear and circular slide rules.

Bonaventura Cavalieri (1598-1647) made many improvements in mathematical formulæ and expounded a new method of indivisibles which solved some of the difficult astronomical problems raised by Kepler, and enabled Torricelli, Viviani, de Roberval, and others to solve abstruse problems relating to all types of curved figures.

Pierre de Fermat (1601-1665), one of the greatest of French mathematicians, developed rules for calculating maxima and minima. His functions in this type of equation closely approached those of the differential calculus. The calculus was developed from Fermat's work by Lagrange, Laplace, Fourier, and other Frenchmen.

Pascal and Fermat developed the theory of probability. Pascal worked out many useful methods for dealing with curves.

The intense mathematical activity in England and France resulting from the stimulation given by the invention of Napier, prepared the way for the discovery of the infinitesimal calculus by Newton and Leibnitz.

Newton was born in England the same year that Galileo died in Italy. His greatest work is presented in his celebrated "Principia," or "Mathematical Principles of Natural Philosophy," in which the law of gravitation, the laws of motion, and the mathematical principles of mechanics are developed. The "Principia" was published in 1687, and it has ever since been regarded as the corner stone of mathematical and physical science.

CHAPTER VIII
SCIENCE IN THE SEVENTEENTH CENTURY

The wonderful advances made in the mathematical, physical, and astronomical sciences, and the invention of many new scientific instruments, together with the publication of improved textbooks and scientific tables, like those mentioned in the preceding chapter, stimulated interest in other fields of science at the beginning of the seventeenth century.

Medicine, which failed to advance with the astronomical and physical sciences, began to improve. The Moors had established great medical schools in Spain, but their teachings were based upon the principles enunciated by Hippocrates and the Greek schools.

Modern medicine was started upon a firm basis by John Harvey (1578-1657). Hippocrates taught that the blood was one of the principal parts of the body—one of the four great "humors." Its movements, however, had never been investigated until Harvey began to study the functions of the arterial system by the dissection of animals. The arteries had been considered as merely air tubes. This was due to the fact that they were studied only in post-mortem examinations when they were empty. The anatomists of the sixteenth century failed to grasp their importance.

Harvey, who was a penetrating observer, had studied in several continental universities as well as in England, and having an original mind he determined to test the medical theories which he had been taught. His discoveries of the functions of the heart, the arteries, and the veins were epochal. He did his work so well and made such simple, yet telling, demonstrations that he had less difficulty than his predecessors in getting his teachings accepted. He was soon recognized as the peer of Hippocrates and Galen.

Harvey died without actually seeing the blood coursing from the arteries into the veins, but four years after his death Marcello Malpighi (1628-1694) exhibited microscopically the passage of blood corpuscles through the minute vessels in the lung of a turtle, on their way from the heart through the arteries into the veins and returning to the heart. The blood circulation was demonstrated at a subsequent date by applying a microscope to the web of a frog's foot. With low-powered lenses a good view is obtainable in this manner.

Many other important discoveries were made by Harvey, particularly in embryology. He demonstrated that the embryo chicken is formed by gradual development and processes of differentiation and not, as had previously been believed, from a minute perfect chicken.

Microbes were discovered in 1683 by Antonius von Leeuwenhoek (1632-1723), when he was examining some scrapings from his teeth. He saw for the first time the long and short rods of bacilli and bacteria, the spirillum and the micrococci. He tried means for destroying them and met with a fair degree of success with a gargle composed of a mixture of vinegar and hot coffee. This experiment was one of the early anticipations of antiseptic surgery, which was invented by Lister in the nineteenth century.

A French surgeon, Ambroise Paré (1517-1590) was a pioneer in the treatment of wounds. The old method was to use boiling oil. He found that by simply cleaning and bandaging wounds he could get better and quicker results than with hot oil, which was a very painful treatment. Paré used ligaments in stopping hemorrhages, improved the surgery in harelip and hernia operations and for suprapubic lithotomy. He learned the principles of these operations from Peter Franco (1505-1570), an itinerant surgeon, who had much skill in operations for kidney and bladder troubles.

Franz de la Boë (1614-1672), a professor in the university of Leyden, who is best known under the name of Sylvius, the discoverer of the brain fissure of Sylvius, founded a new school of chemical medicine. Van Helmont suggested to him the possibility of the stomach being the seat of many common disorders. When this was investigated, many experiments were made with new medicines. The success of these experiments led to a great reform in medical practice. Thomas Willis (1622-1675), an English physician, completed the development of the treatments suggested by Van Helmont and Sylvius as a result of their studies of the works of Harvey.

Another great English medical genius arose to establish the practice of medicine on a scientific basis. Thomas Sydenham (1624-1689) founded a school of medicine in accordance with these three principles: (1) Accurate descriptions of the courses of diseases, (2) following a fixed method of treatment in each disease, (3) searching for specific remedies for each diseased condition.

The results of these teachings were very pronounced. Before Sydenham's time, the only drug used in medicine was an extract of cinchona. The Dutchmen above named and Sydenham discovered many active medicinal substances. Sydenham's principal discovery in materia medica was that of the properties of laudanum.

William Gilbert, court physician to Queen Elizabeth of England, while Galileo and Stevin were developing the laws of gravitation and hydrodynamics, undertook the investigation of the laws of terrestrial magnetism and chemistry. His researches in chemistry were extensive and valuable. His fame, however, was perpetuated by his study of magnetism and electricity. He found that the earth is a vast magnet with north and south poles. His remarkable textbook on magnetism covered many of the fundamental facts known to-day. He noted the distinction between magnetism and electricity, described electrical charges, the principles of conductivity and methods for magnetizing iron. Galileo wrote of him: "I extremely admire and envy this author."

The mercurial barometer and its laws were discovered by Evangelista Torricelli (1608-1647) a student of Galileo. By means of his barometer, Torricelli was able to make great advances in knowledge relating to the physics of the air and to gas pressures, and he investigated the principles of hydraulics. The microscope, telescope, sextant and other instruments were greatly improved by him, and his mathematical work ranks only second to his contributions to experimental science.

The Torricellian tube, used as a barometer, was a means of creating a vacuum, which was formed at the top of the column of mercury. Pascal, the French mathematician, took up the study of the physics of the vacuum and published an important work on his own experiments. These and other experiments made by European scientists prepared the ground for, and suggested, the investigations of gases and vacua by Boyle, Mariotte, and others which finally resulted in the invention of the steam engine and many other modern machines.

Robert Boyle (1627-1691) published at Oxford in 1660 a book which distinguished between chemical compounds and chemical mixtures. He adopted the use of the term gas, which was first proposed by Van Helmont, and made some valuable studies on the physics of boiling and freezing. The oxidation of metals, the results of calcination, and of the fusing of metals and alloys, calculation of the atmospheric pressure, a study of colors as affected by light rays, and investigations in electricity were among the scientific works carried out by this great experimenter. But his fame rests mainly upon the results of his researches on gases.

Boyle began life as an alchemist and died a well-trained chemist.

Edme Mariotte, a French contemporary of Boyle's, carried out similar experiments and assisted in formulating the physical laws of gases bearing the names of Boyle and Mariotte.

A German physicist, Otto von Guericke (1602-1686), also followed up Boyle's work and invented a new form of air pump. He also carried on important experiments in electricity.

Gilbert, Harvey, Van Helmont, Torricelli, Boyle, Mariotte, and other similar pioneers in scientific methods not only invented numerous valuable instruments and wrote suggestive textbooks, but advanced scientific learning and the love of it by their delightful accounts of their experiments.

Modern education started with these men. Before this period there had been a sterile age in which the fundamental purpose of education was only to teach men how to protect the soul and to serve God. This humanistic principle, however, failed to advance knowledge of the laws of nature, and the researches of the scientists gradually caused a strong reaction against it. This in turn resulted in further advances being made, not only in the sciences, but in all departments of learning. The way was paved for the era of naturalism, developed by Hobbes, Locke, Descartes, Voltaire, Kant, Rousseau, and others. Naturalism aimed at explaining all phenomena in the simplest terms, and correlating all things by universal principles. It has received a great impetus in modern times from the Darwinian theory of evolution.

The great scientific discoveries of the sixteenth and seventeenth centuries had other important educational effects. They led to professional specialization and the founding of scientific institutions, schools, and universities. The Lyncean Society of Scientists was founded in Italy in Galileo's time. It subsequently became, in 1657, the Accademia del Cimento.

The Royal Society of England was organized about 1645 and chartered in 1662. It did much valuable scientific work from its inception. It has assisted the foremost scientists in their work, directed scientific researches, and financed the printing of scientific records and the carrying out of foreign expeditions. Nearly all the leading countries in the world have formed institutions with similar aims.

The chemical discoveries of Boyle attracted widespread attention and led to investigations started with the view of discovering the constitution of matter. Hermann Boerhaave (1668-1738) of Leyden, took up the study of organic chemistry. Stephen Hales (1677-1761) did similar work in England. Both of these chemists invented valuable laboratory processes and instruments. Hales improved the pneumatic trough used for collecting gases.

Scientists were now furnished with the telescope, compass, sextant, microscope, barometer, thermometer, air pump, manometer, and other instruments so that cellular structures of plants, animals, and insects, the microbes and bacteria, the animalculæ found in water and in the sea, as well as the phenomena of the air, sky, and earth crust could now be studied by trained observers. The invention of these instruments caused workers to specialize more and more, and completely severed science from philosophy, of which it had been an appendage since the earliest times.

The microscopical investigations of Malpighi, Kircher, Leeuwenhoek, Grew, and Hooke opened up an immense field for research. They developed microscopical chemistry and anatomy, and changed the prevailing ideas regarding animal and vegetable tissues. The sciences of mineralogy, botany and entomology were benefited and the medical sciences were practically revolutionized. The first publications of the Royal Society show the widespread attention microscopical and telescopic studies were then receiving.

Copyright, Keystone View Co.

WEATHER AND ASTRONOMICAL INSTRUMENTS ON THE ROOF OF GREENWICH OBSERVATORY, ENGLAND

Courtesy "Aeronautics," London

A MOORING TOWER FOR AIRSHIPS, WITH THE R-24 FASTENED HEAD ON

Francis Bacon (1561-1626), René Descartes (1596-1650) and Gottfried Leibnitz (1646-1716), in England, France, and Germany, respectively, lent powerful aid to the advance of science at this time.

Bacon's great learning enabled him effectively to describe scientific methods and to direct scientific criticism. He attracted general attention to scientific methods based on inductive processes.

Descartes, seeing that the world's best intellects had long been exercised with philosophy and metaphysics, without discovering anything with certainty, resolved to accept no beliefs upon the authority of any name or reputation. He would reach his own conclusions based upon the scrupulous examination of data. He hoped to solve the mysteries of nature by the aid of mathematics and geometry, and developed the Cartesian philosophy.

The mathematical works of Descartes are now better known than his general scientific ideas. He published in 1637 his "Discourses on Method" and on Geometry. In the last-named work, suggestions are given for the development of analytic methods. It has been said of his formulæ that they are even cleverer than himself. The general use of his analytic methods by other mathematicians resulted in the solution of many scientific problems that had been handed down for centuries as insoluble.

Descartes also advanced algebra. The application of the doctrine of curved lines to algebra greatly enlarged the scope of its usefulness. In making these innovations, Descartes introduced the methods and symbols of modern exponential notation. The English mathematician Wallis was also an important agent in the development of mathematical notation. He based his work on the Greek notation and that of Nicolas Chuquet (1484), J. Bürgi, Thomas Harriot (1631), Johann Hudde (1659), and others. Descartes was familiar with the writings of these scholars and, undoubtedly, was influenced by them.

Roberval, Fermat, and Pascal were contemporary mathematicians in France and left great names in the history of the mathematical sciences. They all made contributions which permanently enriched mathematics and made further progress in other sciences possible.

The geographical sciences now began to attract attention. The new scientific instruments made it possible to collect data in all parts of the world that was needed in unraveling scientific mysteries.

William Dampier (1653-1715) was one of the pioneers in scientific voyages of discovery. In voyages to the Orient and Australasia he collected much important data on zoölogy, botany, meteorology, the winds, tides, currents, and on fish and sea life. His book on winds became the first great standard work on meteorology.

The doctrine of spontaneous generation had long held sway in Europe. The Greeks entertained it and it was accepted as true in the time of Martin Luther. Francesco Redi (1626-1697), an Italian biologist, showed that when the flesh of dead animals is protected it remains fresh. The Abbé Spallanzani (1729-1799) carried Redi's theory further and showed that microbes and bacteria do not develop in concoctions which have been boiled and sealed. Here we note the beginning of antiseptic science.

Under the leadership of Bacon in England, Calvin in France, Luther in Germany, and Knox in Scotland, European thought was being stirred up while the great discoveries just related were being made. Just as Boyle's chemical discoveries caused the divorcing of chemistry from alchemy, and the naturalistic philosophy of the times led to the specialization of scientists and the breaking off of philosophy from science, so the intellectual awakening aroused by Bacon and his contemporaries led to the suppression of belief in witchcraft and to revolutionary ideas in religion and ethics.

Locke endeavored to base a "rational Christianity" on the ground of experience. Until his times, theology was tangled up with a maze of physical problems which dismayed even such intellects as those of Newton, Hume, and Locke.

Newton's researches were chiefly based upon mathematical and astronomical problems. While a student at Cambridge in 1660, he studied the works of Descartes, Kepler, Van Schooten, Barrow, and particularly those of the Greek and British mathematicians. The works of J. Wallis were very valuable to him. The "Arithmetic of Affinities" of Wallis drew his attention to astronomical problems and thus led to his great triumphs later on.

Newton's "Principia" has already been referred to as being one of the greatest works of the intellect ever produced.

The result of Newton's meditation upon the nature of the central force that keeps the planets in their courses was that he furnished a mathematical basis for Kepler's laws by proving that if the planets describe elliptical orbits about the sun, the force acting toward the sun, keeping them in revolution, must vary inversely as the square of the distance. On the revolution of the moon around the earth he found a practical confirmation of this law of gravitational attraction. He then took up the study of motion in general and showed that every particle of matter attracts every other particle in accordance with the same principle of inverse squares.

Botanical gardens were established in Padua in 1545, and not long after in Pisa, Leyden, Paris, and London. Much attention was devoted to medicinal plants, and numerous herbal books were published. Malpighi, Grew, and Camerarius (1665-1721) published works on botany and plant morphology. Ray and Linnæus (1707-1778) studied the classification of plants and compiled textbooks of descriptive botany.

Buffon (1707-1788) published his famous "Natural History of Animals" which did for zoölogy what the works of Linnæus did for botany.

Looking backward, we can now see that all scientific knowledge has been gained by the trial and error method and cumulative analyses of a multitude of observations. Progress is not made uniformly but in a recurrent, cyclic manner. Reactions follow advances, but in the end all goes forward.

CHAPTER IX
PRELUDE TO MODERN SCIENCE—THE EIGHTEENTH CENTURY

When the eighteenth century opened science had begun to make men think, and the works of the great scientists had changed the trend of thought on all sides. Liberty of conscience, of worship, and of opportunity were demanded, as well as representative government, economic freedom, and individual equality before the law. Men wanted to be free agents. The philosophical writings of Berkeley, Locke, Hume, Spinoza, Voltaire, Rousseau, and others supplemented the books of the scientists and promoted rational thinking. Syllogistic reasoning displaced the practice of accepting beliefs upon authority. This change in public thought reacted most favorably upon science.

Gottfried Wilhelm Leibnitz (1646-1716) conceived matter as a plurality of simple forces. Many kinds of matter, he said, exist. There is no single natural force, but an infinite number. Each force is represented by some individual substance. Force is indivisible, immaterial, and unextended. Simple forces he called essential forms, units, atoms, or monads. The monads are not mathematical points, nor physical points. Real points are metaphysical. In other words, Leibnitz created a philosophy of eternal force atoms.

The Greeks were taught by Leucippus, Empedocles and Anaxagoras that matter is formed of atoms. Space is infinite; atoms are indivisible. Atoms are in a continuous state of activity. Atoms constitute worlds and planets. Falling through space they give rise to eddying motions by mutual impact. Many philosophers rejected these views. Throughout the ages, however, they were learned by students and when Leibnitz advanced his new atomic theory, the world was ready to consider it. The Leibnitzian monads were like Plato's ideas—eternal purposes. Aristotle held that monads are absolute, indivisible beings. Leibnitz suggested that each monad is in process of evolution and realizes its nature through inner necessity. It is not determined from without. Each form of matter existed in germ in an embryo. Nothing in a monad can be lost, and future stages are predetermined in the earlier stages. Each monad is charged with the past and big with the future. The biologists at this period generally accepted this incasement theory. Caspar F. Wolff suggested, in 1759, that there is an epigenesis or a progressive evolution and differentiation of organs from a homogeneous primitive germ. This view did not meet with approval until Darwin published his great discoveries in the middle of the last century.

The history of the atomic theories furnishes a clear illustration of the long period of preparation that great scientific ideas must pass through before they are united by a generalizing genius of exceptional capacity and launched in the form of a new theory.

Modern mathematical science grew out of the analytical geometry of Descartes. He showed that the true method for the discovery of scientific facts was to accept nothing as true which was clearly not recognizable as true. All assumptions should be proved. Each difficulty should be separately studied. No intermediate steps should be skipped, and details should be methodically enumerated. Thoughts must be guided in an orderly manner, beginning with the simplest characteristics of an object and proceeding in a logical sequence to the most complicated aspects of each subject. Descartes carried out his own rules in his work. His improvements in the differential calculus, and those in the integral calculus made by Cavalieri, and in the calculus of probabilities by Pascal and Fermat, furnished scientists with instruments capable of solving almost every physical problem met with in their investigations.

One of the first results of the new analytical methods was the establishment of the science of optics.

Newton demonstrated that white light is composed of rays of various colors, and that the color reflected by any object is due to the ability of the object to reflect certain rays while absorbing the rest. The Dutch physicist, Huygens, championed the undulatory or wave theory of light. Refraction was explained by both Newton and Huygens, and the latter, while studying the double refraction of crystals of Iceland spar, discovered the phenomena of polarization.

Boyle's chemical discoveries led to much research in chemistry. Black, Bergman and Van Helmont investigated the properties of carbonic acid gas.

Joseph Black treated limestone with acid and collected the gas evolved in a Hales pneumatic trough. He weighed the gas and the remainder of the limestone, finding that what the limestone lost was equivalent to the weight of the gas. He then reversed the process and succeeded in making chalk from a solution of lime. This simple experiment paved the way for chemical analysis and syntheses which have added profoundly to our knowledge of the composition of matter.

Bergman tested Black's gas with litmus and found it gave an acid reaction and in 1779 Lavoisier demonstrated that it consisted of carbon and oxygen.

Priestley and Cavendish, both English chemists, then took up this study. Cavendish treated iron, tin, zinc, and other metals with sulphuric acid and discovered a new gas which he termed hydrogen.

Rutherford discovered nitrogen in 1772 and Priestley isolated nitric oxide, and in 1774 discovered oxygen. In the course of his experiment Priestley also discovered ammonia, sulphur dioxide and other chemicals.

His greatest achievements, however, were the isolation and recognition of oxygen, and the discovery of the composition of water. Following up these discoveries, he noted that the air is not a simple elementary substance, but a mixture of nitrogen and oxygen with several impure gases. The work of this great chemist became as fruitful in the chemical field as that of Newton in physics, astronomy, and mathematics.

Carl Wilhelm Scheele, a Swede, carried out many experiments which resulted in the discovery of tartaric acid, the decomposition of silver chloride by light, magnesium nitrate, magnesia, microcosmic salt, and sulphureted hydrogen, chlorine, hydrofluoric, and other inorganic acids. He also discovered the following organic acids: lactic, gallic, pyrogallic, oxalic, citric, malic, mucic and uric. He isolated glycerin and sugar of milk and determined the nature of hydrocyanic acid, borax, plumbago, Prussian blue, and other chemicals. He invented many new chemical and laboratory processes. Scheele was an apothecary's assistant and lived in poverty. But although his experiments were conducted under disadvantageous circumstances his discoveries ranked him as the greatest chemist of his time and one of the greatest chemical experimenters of all time.

Cavendish established the proportions of the constituents of air, demonstrated the nature of water and its volumetric composition. The character of the experiments conducted by Cavendish, his elegant methods of weighing, measuring and calculating have caused him to be looked upon as the founder of systematic chemistry. He was more scientific in his methods than the brilliant Lavoisier, and much more learned and philosophical than the practical Scheele.

While the chemists were making these great advances there were important developments in physical science. Benjamin Franklin (1706-1790), the first American scientist to acquire world-wide fame, announced that lightning was an electrical phenomenon. In 1752 he showed by his famous kite experiments that atmospheric and machine-generated electric charges are of a like nature.

Franklin suggested to Cavendish certain electrical experiments with a view to studying the electric force between two charges. These experiments led Cavendish to the discovery of the law of electric attraction between charged bodies. Franklin subsequently discovered the law of conservation of an electric charge.

Charles Augustin Coulomb (1736-1806) rendered great service to electrical experimentation. He resurveyed the experiments of Cavendish, Priestley, and other pioneer electricians, and established a theory of molecular magnetization which provided a working formula to explain electrical currents and magnetic fields.

Simeon Denis Poisson (1781-1840) discovered the law of induced magnetism which bears his name.

Luigi Galvani (1737-1798) observed that the limbs of a frog are convulsed whenever they are connected up through the nerves and muscles with a metallic arc formed from more than one metal. He thought the convulsions were due to a peculiar fluid which he called galvanism, or animal electricity.

Another Italian, Alessandro Volta (1745-1827) discovered and explained the theory of the voltaic pile.

Nicholson and Carlisle discovered frictional electricity while William Cruickshank showed that a voltaic current decomposes solutions of metallic salts. William Hyde Wollaston used Cruickshank's discovery to prove that frictional and voltaic electric currents are identical. Humphry Davy (1778-1829) in 1807 established a new voltaic theory which combined the chemical and contact theories previously held, and showed that electrical and chemical attractions are produced by similar causes. Chemical affinity he found to be an essentially electrical phenomenon.

Francis Hawksbee, in 1705, communicated to the Royal Society a monograph which showed that when common air is passed over mercury in a well-exhausted receiver an electric light is produced. This was the first demonstration of the availability of electricity for the production of light.

Dufay (1699-1739) described positive and negative electric currents.

Watson determined, for the Royal Society, the velocity of an electric current and found it practically instantaneous.

These, and numerous lesser, discoveries did for electricity what the chemical discoveries of Priestley, Cavendish, Scheele, Boyle, Lavoisier, and others had done for chemistry.

The numerous voyages of discovery in the eighteenth century helped to develop the geographical sciences. Special expeditions were fitted out for the acquirement of geographical knowledge without any thought of trading profits. The Jesuits carried out a valuable survey of China and Mongolia early in the century. A Danish scientific expedition studied Arabia, the results of which were published by Niebuhr in 1772. James Bruce visited Abyssinia with the view of solving the ancient problem of the source of the Nile. Mungo Park studied the course of the Niger. Captain James Cook led a scientific expedition to Tahiti with the object of making astronomical observations. This resulted in one of the greatest and most valuable voyages of discovery in history. Cook determined the westernmost point of America in 1778 and his accounts of Bering Sea and Alaska revived interest in the Polar seas, which resulted in numerous Arctic and Antarctic expeditions yielding rich scientific returns.

The Hudson's Bay Company sent out many investigators to determine the characteristics and resources of Arctic America. The Russians did the same for their own northern lands.

These activities of geographical investigators led to improved methods of navigation, nautical surveying, sounding and shipbuilding, besides supplying an enormous amount of scientific data.

The British naval authorities pointed out to King Charles II the need for correct nautical tables. Flamsteed, one of the leading astronomers of the day, was appointed Astronomer Royal in 1675, with the definite object of producing a new catalogue of star positions, tide tables, and other nautical data. He immediately founded the Greenwich observatory, which has supplied the world with data for the navigator.

Bradley, a successor of Flamsteed at Greenwich, made many important astronomical discoveries while carrying on the star maps. He discovered the aberration of light and the mutation of the earth's axis.

Locaille studied the parallax of the sun and made numerous stellar observations at the Cape of Good Hope in 1751. He located the positions of 10,000 stars in the southern hemisphere.

Measurements were made in Peru, Lapland, and elsewhere to discover data regarding the earth's curvature. Pendulum observations to detect variations of gravity were made in many countries. Maskelyne, the astronomer royal, made observations on the transit of Venus at St. Helena in 1761. On this expedition he perfected the method of finding longitude at sea by lunar distances.

Sir William Herschel discovered the planet Uranus in 1781, and subsequently found its satellites. Many star groups, double stars and nebulæ were discovered by him and he found that the solar system is traveling through space in the direction of a point in or near the constellation of Hercules.

Greenwich observatory was publishing at the end of the eighteenth century the Nautical Almanac, and annual reports on star and meteorological observations as well as important astronomical monographs. Similar publications were founded in the next century in France, Germany, and Italy.

The discoveries in mathematics during the eighteenth century included the differential, integral, and other forms of the calculus, differential equations, and various formulæ for dynamics, mechanics, and physical and astronomical calculations. Euler, Lagrange, Laplace, D'Alembert, and Carnot were prominent mathematical investigators.

Heat in earlier times had been regarded as an imponderable substance called caloric which was supposed to be emitted by hot and absorbed by cold bodies. Thus the expansion of mercury was explained by the addition of caloric and not by the increase of distance between the molecules. Francis Bacon and the Scotch chemist Black did the preliminary work which enabled Count Rumford finally to establish the true theory of heat. Watt and Newcomen were attracted by these studies and reduced their theories to practice in the steam engine. Black described specific and latent heat and invented, and used, the calorimeter bearing his name.

Hall invented an achromatic lens for telescopes in 1733, and Dollond, another English optician, improved achromatic lenses and made, in 1758, achromatic telescope objectives. The lenses were primarily designed for astronomical telescopes, but they were also applied to microscopes and other scientific instruments, resulting in improvements in our knowledge of light.

The voyages of discovery, in this century, encouraged study of zoölogy and natural history subjects generally, including mineralogy and geology.

Hooke, Ray, and Woodward made collections of rocks and fossils in England and advanced hypotheses to explain their origins. Lazzaro Moro suggested that fossils must have been deposited in rocks when they were being formed. He also distinguished rock formations by the characteristic fossils found in them. Hutton and Smith then made scientific studies of English rocks, fossils, and earth sculpture, and prepared the materials for the subsequent brilliant discoveries of Lyell.

The first governmental school of mines was established in Freiberg, Saxony, in 1775. This institution, and others which were afterward established in different countries, led to an intensive study of the geological and metallurgical sciences, which eventuated in great advances during the nineteenth century.

Aristotle and Theophrastus in early times, Gesner in the sixteenth century, Ray, Grew, Malpighi and Willughby in the seventeenth century, had been the writers of the principal textbooks on zoölogy. Buffon (1707-1785) and Linnæus (1707-1778) were the founders of modern natural history in the eighteenth century. Buffon described species, while Linnæus classified them. Linnæus named Homo sapiens as a distinct species in the order of primates which includes apes, lemurs, and bats, and fixed man's place in nature.

The medical sciences were revolutionized by the researches of Edward Jenner. He applied the scientific methods of the chemists, mathematicians, and astronomers to medicine and through accurate observation, skillful experimentation, careful generalization, and thorough verification, founded preventive medicine. His discovery of vaccination as a preventive for smallpox, communicated to the Royal Society in a very interesting paper in 1798, was the pioneer of the many brilliant advances of our day.

The Freiberg School of Mines, the Woolwich Observatory, the School of Civil Engineering in Paris (1747), the Universities of Göttingen (1737), Bonn (1777), Brussels (1781), Yale (1701) and Princeton (1746) were founded in this century.

Modern industrialism began in the final part of this century. The invention of the steam engine by Watt resulted in giving the greatest impulse to material civilization the world ever experienced. This invention was the direct result of the experimental work of Boyle, Newton, Black, Cavendish, Davy, Priestley, and Lavoisier. It illustrates how the scientific discoveries of one generation furnish the data for the advancement of knowledge by the next generation and how a single invention may change the whole aspect of life, giving employment for vast numbers of people, developing settlement in foreign lands, starting new industries, and extending the fields of commerce. The history of the development of the steam engine from the results of a few basic physical researches by British scientists forms one of the grandest stories in the history of science.

The new aspect assumed by the world as a result of the great scientific discoveries and the increases in industry and commerce which followed them seemed strange to the people who were unused to rapid progress. There was a disturbed feeling akin to fear abroad while the new ideas were being popularized and disseminated throughout the world. The movement in favor of enlightenment was strongest in France because of the social, political, and religious oppression of the people. It ended in the French Revolution, which strengthened the respect for reason and human rights throughout the world.

CHAPTER X
PHYSICAL SCIENCES IN THE NINETEENTH CENTURY

During the nineteenth century, the path of scientific discovery might almost be represented by a vertical line. Never before was such rapid and marvelous progress made. The releasing of the mind from the oppressive restrictions of earlier conservative ages liberated the intellectual energies of mankind. A new idealistic philosophy supplanted that of an earlier period and universal attention was given to science and material things. Amidst these changes social science was devolved, and, with it, the study of psychology.

But it was the physical sciences which most felt the stimulus of the new rationalistic spirit.

The relationships between physical magnitudes are established by measurements. When these are accurately ascertained, questions regarding their variable functions can be solved by mathematical principles. Physics is thus linked with mathematics through measurements. The more science advances, the greater is the accuracy needed in physical measurements. The strictness and clearness of experimentation which has been attained in physics has given birth to a science of measurement, which has its own instruments, rules, methods, and formulæ.

Measurement of length is one of the bases of physics. It is a relative operation carried out by comparing the length of one body with that of another. Standards of length are preserved by a Bureau of Weights and Measures in most countries. Delambre, a French authority on the decimal system of measures, taught at the beginning of the nineteenth century that magnitudes as small as the hundredth of a millimeter are incapable of observation. The International Bureau of Weights and Measures now guarantees to determine two or three ten-thousandths of a millimeter. So much has the science of measurement progressed in a century.

The undulations of light rays are used for determining standard lengths. Michelson and Benoit measured a standard length of ten centimeters, in 1894, in terms of the wave lengths of the red, green, and blue radiations of cadmium, and then in terms of the French standard meter. These experiments yielded very accurate results.

The measurement of mass is another important base of physics. Mass is the quantity of matter in a body and the action which gravity exerts on mass is called weight. Weight does not depend entirely upon mass, but also upon the position of the body weighed, because when the body is weighed in one place and reweighed in another, there will be a difference in the force of gravity due to change of latitude and of altitude. National standards of mass have been made of alloys of iridium and platinum.

Many remarkable measurements of time, temperature, and physical constants were carried out during the century.

High and low temperature charts were completed, showing temperatures in the air, the earth, and the sea. Instruments and methods were devised for measuring any temperature whether of high furnace gases or low freezing mixtures.

The measuring units of mass, length, time, and temperature are fundamental, others like velocity, acceleration, power, and area are referred to them. For that reason the latter are called derived units. Many of these are important and call for accurate determinations.

One of the first achievements of the century was the establishment of the doctrine of the conservation of energy.

Francis Bacon had suggested that motion is a phenomenon of heat, and Newton had divined the principle of the conservation of energy, but it was Benjamin Thompson, Count Rumford, who discovered the nature of friction and made the first estimate of the mechanical equivalent of heat. Sir Humphry Davy showed that two pieces of ice could be melted by simply rubbing them together, in a vacuum. But he failed to draw the great inference that this experiment warranted.

If he had observed that the heat could not have been supplied by the ice because ice is an absorber of heat, he would have anticipated the great work done by James P. Joule, an English physicist, who published the results of many experiments carried out by him prior to 1843. His task was to find the exact mechanical equivalent of heat.

His best results were secured by dropping a mass of lead from a measured height and using the energy generated during the descent to operate a revolving paddle in a dish of measured water. Delicate thermometers recorded the increase of temperature in the water and showed that the descent of 424 grams of lead through a distance of one meter, or one gram of lead through 424 meters, generated sufficient heat to raise one gram of water one degree centigrade (1° C.).

Otherwise expressed, a fall of 772 lbs. of lead through a distance of 1 foot, or 1 lb. of lead through 772 feet, raises the temperature of 1 lb. of water one degree Fahrenheit (1° F.). These 772 foot-pounds, or 424 gram-meters, represent the mechanical equivalent of heat upon which so many important theories have been based. But Joule's equivalent was determined for common air temperatures whereas the specific heat of water increases with the temperature so that the value of the equivalent rises with increased temperatures. Osborne Reynolds, in 1897, found the mean equivalent for temperatures between the freezing and boiling points to be 777 foot-pounds.

The discovery of Joule's equivalent established a relationship between motion or mechanical work performed and the amount of heat generated when work is completely expanded in friction. The same relationships continue good when the work is transformed by indirect means as by generating electric currents or expanding gases. The multitude of elegant experiments used to confirm the truth of Joule's law showed that heat is not a substance, or calorie, but a purely mechanical effect. This great discovery of the relation of friction and heat lies at the basis of electricity, molecular physics, and chemistry, and is the source of the formulæ used by engineers in designing power machinery. The internal combustion engine is largely a result of the discovery of Joule's equivalent and the physical theories derived from it.

This great discovery caused a new theory of matter to be developed. Dalton had suggested, when applying the atomic theory to chemistry, that when two elements combine to form a third substance, it is probable that one atom of one element joins itself to one atom of the other, unless some exceptional condition exists. When water is formed by bringing oxygen and hydrogen together, he supposed that one atom of oxygen combined with one atom of hydrogen. Gay-Lussac subsequently proved that not only does one volume of oxygen combine with two volumes of hydrogen (not one as Dalton believed) in the production of water, but that nitric and carbonic acid gases combine with ammonia gas in the ratio of 1:1 or 1:2. He also demonstrated that one volume of nitrogen united with three of hydrogen form ammonia, and that carbonic oxide burning in a mass of oxygen consumes half its volume of oxygen. He concluded from these and other facts that gases always combine together in simple proportions by volume and that the apparent contraction of volume they show on combining bears a similar simple relationship to the volume of one or more of the gases.

Avogadro, working on Gay-Lussac's experimental data, suggested that the number of integral molecules in any gas is always the same for equal volumes, or is always proportional to the volumes. He also suggested that equal volumes of different gases at the same pressure and temperature contain the same number of molecules. Experiments on alcohol made by Williamson raised doubts as to the validity of Avogadro's hypotheses when applied to chemical combinations. These doubts were cleared in 1860, when the new chemical atomic weights and formulæ were introduced into English textbooks.

The molecular theory of matter derived from these experiments supposes that all visible forms of matter are aggregations of simpler and smaller chemical elements. Mendeléeff and Newlands showed that the physical and chemical properties of the elements are functions of their atomic weights.

Investigations of radioactivity and the observations based upon the passage of electric currents through gases have recently modified our views with respect to the atomic theory, but these points will be dealt with in the chapter dealing with radiation.

Questions regarding the eventual loss of energy in matter are best studied in gases. A considerable number of important investigations are now being carried on in Europe with the view of tracing the interchanges of molecular energies in gas molecules. Maxwell and other investigators found long ago that the motion of molecules cannot go on perpetually. The energy of motion will in time be frittered away by friction, air resistance, collisions with other molecules, vibrations set up by collisions, and other molecular movements. It has been found that the energy which is dissipated by air resistance is transformed into energy in the air. That which is lost by collisions is converted into internal vibrations within each molecule. The question now arises as to what effects are exerted on a gas. It involves the effects of the communicated internal molecular vibrations and their transference of energy to the surrounding medium. What is known as the Quantum dynamic theory has been proposed to account for this phenomena. Quantum dynamics appear to be distinct from the Newtonian.

Carnot and Clausius discovered that the motive power of heat is independent of the agents brought into play for its realization. The motive power of a waterfall depends, for example, on its height and on the quantity of water falling within a given time. Clausius stated the Carnot idea in mechanical terms by saying: That in a series of transformations, in which the final is identical with the initial stage, it is impossible for heat to pass from a colder to a warmer body unless some other accessory phenomenon occurs at the same time. A heat motor, which, after a series of transformations, returns to its initial state, can only supply work, or power, if there exist two sources of heat, and if a certain quantity of heat is given to one of the sources which can never be the hotter of the two. The output of a reversible machine working between two given temperatures is greater than that of any nonreversible engine, and it is the same for all reversible machines working between these two temperatures.

Clausius showed that this principle conduces to the definition of an absolute scale of temperature and there is another factor assisting in restoring physical equilibrium which he termed entropy. It is a variable which, like pressure or volume, serves concurrently with another variable to define the state of a body.

These discoveries of Carnot and Clausius showed the impossibility of finding a source of perpetual motion and helped to solve many of the difficulties in securing efficiency from internal combustion engines. Industrial, as well as scientific results of immense importance have developed from these principles.

Theories on the compressible fluids and elastic equilibrium were developed as the result of work done between 1875 and 1896 by J. W. Gibbs, Helmholtz, Duhem, and others on internal thermodynamic potentials. These theories have proved of incalculable value in elucidating electrical and radiation phenomena.

Another discovery of Gibbs, made in 1876, has also had brilliant results. It is known as the Phase Law. The homogeneous substances into which a material system is divided is called a phase. Carbonate of lime, lime, and carbonic acid gas are the three phases of a system which comprises Iceland spar partially dissociated into lime and carbonic acid gas. The number of phases, combined with the number of independent bodies entering into the reactions, fixes the general form of the law of equilibrium of the system. This discovery of Gibbs has resulted in greatly extending the field of physics. It is of importance in molecular and atomic investigations, in osmosis, electrolysis, and in most questions dealing with thermodynamics.

Light is generally defined as the sense impression received by the eye. It was formerly believed that it was caused by streams of corpuscles emitted by the source of light. This was known as the emission theory. Early in the nineteenth century, the undulatory displaced the emission theory. According to this, light is a transverse vibratory motion extended longitudinally through the ether.

The experiments of Faraday, Maxwell, Fresnel, Hamilton, Green, and others suggested that the undulatory theory required for its validity a new medium different from the atmospheric air and from every substance known to man. Just as the results of investigations into reflection, refraction, diffraction, and polarization showed that the old corpuscular theory of light was untenable, so these experiments seemed to cast doubt upon both the undulatory and emission theories.

Fresnel, when studying problems in polarization, noticed that a theory of light proposed by Hooke appeared to be true. Hooke asserted that light vibrations are not longitudinal but transverse.

Fresnel found by his experiments that the idea of longitudinal vibrations acting along the line of propagation in the direction of the rays would not explain the polarization changes in light. They suggested that there was a transverse movement perpendicular to the ray. When Fresnel's researches were published, physicists realized that if the transverse direction of luminous vibrations was denied the undulatory movement of light would also be denied. Now transverse vibrations cannot exist in any medium resembling a fluid, because it is characteristic of fluids that, so long as the volume continues constant, its different parts can be displaced without the appearance of any reaction. This necessitates the assumption that light needs a solid body for its transmission and Lord Kelvin asserted that this body must be a solid more rigid than steel.

When the vibratory theory was accepted, it became necessary to investigate the nature of the ether and to determine its characteristic properties. Neumann, MacCullagh, Green, and Stokes then developed an elastic solid theory of the ether.

The experiments of Lord Rayleigh, Lorentz, Drude, Larmor, and others suggested that light is identical with electromagnetic disturbances and, consequently, is an electrical phenomenon.

Some of the finest developments in physics during the nineteenth century were in the realm of electricity. They resulted in an enormous extension of the use of electricity in industry and commerce and led to the investigation of radioactivities of various kinds and these in turn are developing investigations of a most brilliant character.

CHAPTER XI
THE NATURAL SCIENCES

Manifestations of animal life are everywhere visible. They may be seen on mountain peaks, in desert plains, and by the seashores. Even the bleak arctic ice fields have their faunas. This extraordinary distribution of life has attracted attention since the dawn of history. Primitive man, by his often beautiful cave drawings, indicated that he studied intimately the wild life surrounding him. The basic facts of natural history were studied by the early peoples of the Near East. The Greeks prepared many books on natural history and anticipated modern evolutionary theories. The natural sciences, however, made slow progress until toward the end of the eighteenth century when Linnæus and Buffon began their great works. When the nineteenth century opened, the broader fields of nature were segregated, classified, and described. Linnæus took broad views regarding the principles of classification based upon general structure, and his work was enlarged and improved by Cuvier.

Buffon contributed suggestions regarding the probable mutability of species with respect to changes in environment, and improved on the old Greek evolutionary ideas by formulating a definite theory of the causes of mutability. He was an important agent in promoting the modern theories of evolution in zoölogy and botany, which have done more than anything else to augment our knowledge of terrestrial life.

The numerous scientific exploring expeditions in the eighteenth and nineteenth centuries collected an enormous amount of data regarding animals and animal life. Early in the nineteenth century this data was worked up and classified. It soon became apparent that the range of any given species of animal is strictly limited. A new science, that of the geographical distribution of life, was developed. This has been very fruitful in defining the true home areas of all species of animals, insects, birds, and fish, and locating their principal paths of migration.

The world has been divided into about a dozen terrestrial life regions, subregions and transitional regions. These have been mapped and described. The work of Dr. A. R. Wallace, in 1876, showed the comparative importance and extent of these life zones and their variable richness in zoölogical forms, the relationships of the species in different zones, and their degrees of isolation. The descriptions of these great geographical zones fill many interesting volumes and cover all the important forms of existing life.

The naturalists who studied particular zones, or classes of animals, frequently did extraordinary work. The bird studies in North America, recorded in a series of wonderful paintings by Audubon, and the studies of Fürbringer and other naturalists, are comparable with Wallace's great book on the Geographical Distribution of Animals, published in 1876.

The morphological researches of Parker, Huxley, Quatrefages, Owen, and others revolutionized many of the subdivisions of natural history and led to important discoveries in biology.

The effects of climate upon the development, migration, and decline of species and upon the extension and upbuilding of civilization have been minutely studied. Kropotkin showed that climatic changes in Asia drove the hordes of native tribes into Europe at early periods. They were forced to migrate on account of droughts leading to a food shortage. Many historical events have been shaped by climatic factors. Just as men who inhabit dry districts are usually nomads on account of their need of seeking new food supplies, so animals and insects are forced to migrate for a similar reason. The life changes wrought by disease epidemics under climatic influences have also been studied and have shed much light upon the origin and development of many organs and upon the habits of animals. Some of the chief inferences arising from investigations on the effects of climatic variations on life are that certain types of climate favor the development of certain animal species; certain climates have prevailed in historical times in centers where civilization flourished greatly. Therefore it may be presumed that definite climatic conditions are required for the specific development of each type of species and for each kind of civilization. Just as history shows that one of the many conditions of human progress has changed repeatedly from century to century on account of variations in climatic factors, so these stimuli have, from the earliest times, swayed and modified all classes of organic life. Climate serves to develop, retard, or extinguish animal characteristics, habits, and development. The study of the rôle of climate in modifying living conditions has disclosed data which throws much light on the philosophical problems surrounding organic life, its laws and progress.

The voyage of the Beagle in 1831, for a scientific cruise to South America, with Charles Darwin aboard as naturalist; that of the Ross Antarctic expedition in 1839, with Sir W. J. Hooker as botanist; that of the Rattlesnake for Australia and the South Seas in 1846, with T. H. Huxley as surgeon, resulted in the assembling of scientific data in natural history fields which, when classified and developed, revolutionized the natural sciences.

The work of the Challenger, in 1872, and many other memorable British scientific expeditions augmented and confirmed the data collected in the earlier explorations.

Harvey's explanation of the movement of the blood by the pumping pulsations of the heart quickened interest in biology. Mayer and Helmholtz, when chemists, had succeeded in artificially making urea and sugar and investigated living organisms from the viewpoint of mechanisms operated on the principle of the conservation of energy. They traced the manifold functions of the body to chemical and thermal energies developed by the destruction of food.

These valuable discoveries were augmented by Schleiden and Schwann, showing that all organisms are built up of living cells. The offices performed within cells by colloids and solutions, and in the nerves by electric movements, were traced.

Investigations into the most minute forms of animal life also furnished startling results. Schwann found, in 1838, that fermenting yeast consists of living vegetable cells, and that organic putrefaction is caused by the activities of such cells. Louis Pasteur (1822-1895) demonstrated that the presence of bacteria in any animal is always due to the entrance of bacteria and microbes from the outside, or by means favoring the abnormal increase of existing germs. He also showed by experiments that diseases like chicken cholera, phylloxera, or the silkworm disease are caused by particular microbes. These discoveries led to the tracing of many common diseases to their special living germs.

While these impressive additions to scientific knowledge were being made, other naturalists were studying the instinctive emotional and intelligent behavior and psychology of animals, both singly and in herds. Animals and insects were found to display signs of intelligence, sometimes of a high order; to live socially, in many cases; and to play and court with emotional attributes. Throughout the animal kingdom, until man is reached, animals are guided in their activities by self and racial preservation.

Play was found to be a fruitful factor in animal education, even in minute insects. The behavior of any animal does not stand alone, but is related to that of others. Animals which hunt, or are hunted, combatants, rivals, mates, and enemies, react upon one another.

Entomology, the science of insects, has been extensively systematized. Practically every phenomenon relating to the insect metamorphosis has been disclosed. The works of Binet, Lubbock, Fabre, and many others have illuminated the psychology of insect life. The charming writings of J. H. Fabre on the life of a fly, on the mason bees, the hunting wasps, the life of a caterpillar, of a grasshopper, of the sacred beetles and other insects, are as thrilling and instructive as any masterpiece of romantic writing. What could be more interesting than Fabre's account of his observations on the glowworm, when he discovered that its luminescence is due to oxidation by air forces through a special lightning tube, and that it occurs in males as well as females and in the eggs and grubs likewise? He shows that the glowworm's life, from start to finish, is one carnival of light. The females are living lighthouses which brilliantly illumine the wild thyme and other flowering plants they haunt on dark nights, making miniature fairylands in country districts.

Studies in the growth and form of living bodies have opened up many interesting problems in physical biology. The cell and tissue, shell and bone, leaf and flower are various portions of matter, the particles of which are moved, molded, conformed, or shaped in obedience to the laws of physics. Forms like those of the lovely wing scales of butterflies, of lace flies, or the spiral shells of the foraminifera are natural diagrams of the results of physical forces. Biologists not only study the nature of the motions of living organisms as animal kinetics, but also the conformation of the organism itself, whose permanence or equilibrium is explained by the interaction or balance of forces leading to static conditions.

The dynamics of cell formation and cell division and their karyokinetic figure drawings are the result of numerous complex physical force struggles brought about by chemical and physiological reactions. Studies of these have shown that the spermatozoön, nucleus, chromosomes, or the germ plasms, which develop organic life, can never act alone. They must be started by other forces which make them seats of energy.

The experiments of George Rainey on the elementary formation of the skeletons of small animals, of Carpenter upon the formation of shells, and those of Professor Harting on the same subjects, have shown how lime solutions acting in conjunction with gelatinous substances, or membranes, build up the numerous geometric shapes of the frames of so many kinds of primitive organisms, and the scales of fish or the extraordinarily beautiful markings and sculpture of shells.

The application of the Cartesian coordinates to the outline of organisms, skulls, bones, and organs of animals has opened up a new field of mathematics—biological research which has yielded many results confirming theories based on other data and supplying facts of great interest that may at any time result in the establishment of important generalizations.

The fact of beauty in animate nature is so pronounced, and man's contemplative delight in beautiful things is so natural that investigations have been made into the æsthetic emotions of other animals. A vast array of facts has been collected which leaves no doubt of the universal appreciation of beauty. The lovely colors of shells, butterflies and birds, the extraordinary beauty of the designs of the frames of the Foraminifera, radiolarians and sponges, the graceful logarithmic spirals of horns and flower and leaf buds, and the charming flowing lines in the shape of the race horse and gazelle, these elements of organic beauty which emphasize and enhance the forms of animals, all contribute to the general embellishment of nature. The combinations of beauty of form, color, and movements in parrots, humming birds, the fish inhabiting coral reefs, butterflies, and orchids, are always perfect. We likewise find that in all parts of the globe, and in each life zone, organic beauty conforms to that of the landscape and the heavens. The biological significance of this universality of beauty in the organic world will be dealt with in the following chapter.

The fishes of the seas, rivers, streams, and lakes have been studied, classified, and described as completely as the insects of the air, the field, the soil, and those parasitic upon other organisms.

The surveys of the Atlantic have brought to light many types of fish which inhabit only the deepest parts of the ocean. These fish are modified in most extraordinary ways to fit their surroundings. Owing to the darkness of their living zones, they are provided with luminescent appendages which are practically similar to the firefly's and glowworm's electric generators. The lights are formed, as in the insects, by the oxidation of material exuded by the fish.

There are more than 180 families of fishes recorded. Each family contains an average of twenty genera and each genus about five species. The known species of fish are, therefore, between 19,000 and 20,000. The Danish naturalist Hensen found 278,795,000,000 fecundated fish eggs per square mile in the summer waters of the Skagerrack. The waters of the seas from the Arctic to the Antarctic limits are full of fish eggs as well as those of shellfish and sea organisms generally. This shows that organic life is as abundant in the sea as anywhere on land.

Just as temperature and salinity are the chief agents of oceanic circulation and current movements, so they are the leading factors in promoting the organic life of the sea.

The vast heterogeneous mixtures of living creatures, comprising vegetable and animal organisms, larvæ, and eggs of fish and animals, which are swept hither and thither by the sea tides are called plankton. This term means the living dust or emulsion of the sea.

It has been shown that vegetable plankton is composed of bacteria and adult microscopic algæ, largely of the Diatomaceæ, Peridinaceæ, Cyanophyceæ, and other primary groups.

The animal plankton comprises a mass of microscopic creatures belonging to the Protozoa, Radiolaria, and Globeriginæ. There are also immense numbers of tiny, invisible crustaceans like the Copepoda, and eggs and spores of all kinds of fish and algæ. These organisms are so dense in certain sea areas that their particular colorations are reflected in the water. The Red Sea, for example, is colored by a reddish algæ; the Baltic and ocean areas near Greenland are colored green by swarms of algæ, and certain tropical seas are often brilliantly colored in the same manner.

Plankton furnishes fish with nutriment. The study of the movements of plankton, at seasonal intervals, has led to the discovery of the causes, extent, and results of the migration of the principal commercial fishes. These researches are so valuable that most large nations support marine biological stations and ships to regularly make observations. The Norwegian naturalist Särs, Sir John Murray, the Prince of Monaco, and others have furnished accounts of the life histories, feeding grounds, metamorphoses and migrations of many fishes, and have shown how the inhabitants of the plankton masses live upon themselves or produce nitrifying or denitrifying bacteria, chemicals, and mineral substances like lime, phosphates, and horny membranous material.

The development of biology and embryology, and the peculiar habits and color schemes of certain fish, insects, birds, and animals led to inquiries about design in nature, the causes of the development of species, and the instincts and habits of animals. Erasmus, Darwin, Buffon, Cuvier, and others began these studies, but it was Charles Darwin (1809-1882), who by the publication of his "Origin of Species" in 1859, first furnished many of the keys to the riddles of organic life. The next chapter will show what has developed from his labors.

CHAPTER XII
ORGANIC EVOLUTION, VARIATION, AND HEREDITY

Science developed when primitive man began pondering over the problems of the creation. He sought the causes of life, of the development of life forms, and the authorship or origin of the uniformity and apparent design in nature. It is, therefore, probable that what we now study as the science of organic evolution is one of the oldest of the sciences. As the ages have rolled on, the origin of life has been explained in turn by theories of: (1) eternity of present conditions; (2) miraculous creation; (3) catastrophism with (a) increases by immigration (b) increases by successive creations; and, finally, by (4) organic evolution.

The term organic evolution means the forming of new combinations of the elements of organisms. It does not mean the arising of an animal or plant out of nothing—a new creation. That idea was exploded long ago. The science which Darwin started surveys the whole course of natural history in terms of four dimensions—length, breadth, depth, and duration. This was the plan which led Darwin to his great discoveries. While studying the minor changes taking place in common animals and plants, and looking over the broad vistas of nature back to the remotest times, he saw how each year countless weak and ill-adapted plants, insects, and animals were killed off. When he reflected that this process has been going on throughout all time, the idea flashed into his mind that it is through this testing ordeal that adaptability of surviving organisms is derived.

One of the grandest conceptions of the human mind is that the apparently complex, inharmonic system of nature has developed from a simple beginning on a cooled globe from a jellylike cell.

The theory of the permanence of species was generally held by biologists before publication of Darwin's first great book. Darwin said that no naturalist of his time doubted the accuracy of the theory of the eternity of existing conditions and they refused to listen to his views regarding the mutability of species.

Darwin put forth the theory of organic evolution by natural selection and the survival of the fittest. The great beauty of this theory lies in its simplicity and its appeal to agencies which we can see in full operation every day and night. The skillful manner in which Darwin marshaled data to substantiate his theory quickly converted the scientific world, and led to revolutionary changes in the general tendencies of knowledge, and in practically all fields of human activity.

Darwin's terse statement of his conception was: "As many more individuals of each species are born than can possibly survive, and as consequently there is a frequently recurring struggle for existence, it follows that any being, if it vary in any manner profitable to itself, under the complex and sometimes varying conditions of life, will have a better chance of surviving, and thus be naturally selected. From the strong principle of inheritance any selected variety will tend to propagate its new and modified form." ("Origin of Species," Intro.)

This statement of the doctrine of the survival of the fittest, suggesting a glimpse at the great pageant of nature from the remotest times, shows how the organisms existing at this moment are the descendants of the victors in the world's greatest battles. The struggles for life, always keen and persistent, shared in by every individual organism, both animal and vegetable, are the instigators of all progress in the natural world. They are nature's means for the attainment of beauty, usefulness, and perfection.

The Darwinian theory was based upon the observed facts that members of any given species are not alike, while their offspring may differ in numerous ways from their parents. The data furnished by zoölogy, botany, physiology, and other sciences supply overwhelming evidence that the present species of animals and plants have arisen through the modification from various causes of many pre-existing species. The organisms with which we are familiar owe their characteristics to the accumulation of a long series of changes similar to those that we may see that they are still undergoing.

The methods pursued in studying variation in species, and its important accompaniment, heredity, consists in comparison, statistical examinations, cultural experiments, and crossbreeding.

Evolution is the process of differentiation accompanying the operations of nature. All the great naturalists before Darwin's time noted facts indicating this universal differentiation, but it required the particularly wide sweep of Darwin's mind to phrase and demonstrate it.

The law of origin by evolution, as Herbert Spencer showed, is not confined to the method of bringing into existence new species of animals and plants. The stars, planets, the geological strata and earth contours and forms, human institutions, social customs, and practically everything in nature are obedient to it.

Much research work in evolution has been done since Darwin stated his theory, but the basic principle of the survival of the fittest remains untouched by criticism. Some of his views respecting minor details of selection and the effects of various factors have been modified or enlarged, and many new evolutionary forces have been discovered. It has also been found that a single cause is usually followed by more than one effect.

Weissmann has drawn attention to the importance of adaptations. Most organic beings are usually closely fitted for the conditions under which their lives are spent.

The principal parts of every animal and plant, and all the points in which one species differs from a nearly related species, have been shown to have arisen on account of their usefulness to the creatures possessing them. As natural selection is always progressive, it follows that no adaptation is ever perfect. There is always progress from the useful to the more useful—a continual striving for greater beauty of form and color and higher efficiency.

Works on evolution furnish an abundance of interesting evidence showing how adaptation works. A single instance may be cited here.

One of the Mexican yucca plants common in our Southern States is pollinated by a moth of the Pronuba family. This moth is adapted for its work by several special organs including a special ovipositor and peculiar maxillary tentacles which are not found in other moths. The female moth collects pollen with these tentacles from several yucca flowers, rolls it into a ball and kneads it into a pellet. When the pellet is ready the moth seeks an unvisited flower and, after depositing a few of her own eggs in the ovary, she climbs the style and forces the pollen pellet into the stigma. This is the way the yucca is pollinated and fertilized. Two important purposes are served by this arrangement: a species of plant and a species of moth, together with those dependent upon them, are enabled to survive by this moth's activities. There are many known cases of similar cooperative adaptation to living conditions.

Quetelet, in 1845, followed by Francis Goltin and Karl Pearson, have applied statistical methods in dealing with evolutionary problems, and a new science called biometry has been developed. This science has yielded much important data regarding the effects of inherited characteristics.

The studies of variations in plants by mutations, made by the Dutch botanist De Vries, have opened up wide fields of study regarding the causes of variation. He has shown that increased bulk or better coloration may result from improved nutrition and more light, and that such improved characteristics may be inherited.

A law of ancestral heredity has been worked out for men by biometricians, and this has been confirmed by the experiments of Professor Johannsen, of Copenhagen, on self-fertilizing beans, and by Jennings on protozoa. This hypothesis suggests that every ancestor of a particular man or woman contributes its quota to the heritable qualities displayed by that individual. The average amount of resemblance between an individual and any of his particular ancestors is capable of being numerically expressed.

The experiments and conclusions of Gregor Mendel (1822-1882) tend to oppose the law of ancestral heredity, but it is believed that any exceptional cases may be explained by the operation of special conditions.

Karl Pearson has shown by the analyses of numerous statistical records of Englishmen that by artificial selection any selected characteristic, such as facial contour or stature, can be changed within a few generations. But when the character has been changed about 90 per cent within a short time another method must be employed, because the original one then becomes less efficient.

Individuals in any given population who differ in size from the mean of the population give rise to offspring which differs from that mean value in the same direction but to a smaller extent. The same law applies to the color of the hair or to intelligence or constitution. Selection will always produce a change in the average character of a population taken as a whole. But selection within a pure line, or one which shows only normal variability about a mean or type value, does not produce marked changes.

The usual selection within any particular population consists in the partial separation of extreme types.

The personal characteristics of any ancestor do not influence his descendants. Only the typical characteristics are handed down.

These and many other facts developed by investigations in biometry should be of value in regulating immigration, so as to guard against degenerative influences, and they have greatly increased the efficiency of farming by showing how to improve farm stocks and crops so as to yield larger returns. Farmers have been more ready than politicians to avail of their advantages. We note how the speed of racing and trotting horses, and the milking capacity of cows, have been improved by the past century, but we are doing little to reform national health and efficiency.

Mutation is the name given to the process of origination of a new species or character accomplished by a single step or by a series of steps.

Bateson, in 1894, showed that symmetry is a characteristic common to all organisms. This may affect the whole or parts of an organ. Major symmetry involves the whole organism and minor symmetry only an organ or part. There are meristic variations, involving the symmetrical pattern, and substantive variations involving changes in the constitution or substance of the organism. Red-flowering plants, for example, may yield offspring bearing white flowers. Substantive variations are often discontinuous, or accidental, and are infrequent.

Organic bodies are built up of a number of cells. The living material of cells is protoplasm formed out of many elements, of which carbon, oxygen, hydrogen, nitrogen, and sulphur are the more important. New cells arise from bipartition of existing cells. Therefore by following back the history of any animal or plant we will arrive at a stage when its ancestors had only one cell. Every animal or plant which is propagated sexually actually starts as a cell and develops through its main evolutionary changes in the embryonic state. Cells are liable to all the evolutionary changes that the organism as a whole is subject to.

Studies of embryology have shown that the fusion of biparental reproductive cells results in the formation of a complete new individual which, at the time of the fusing of the two conjugating cells, called gametes, or germ cells, inherits the characteristics of each parent and its ancestors.

The determination of the sex of the cell, plant, or animal, depends upon the presence of extra male or female sex-chromosomes, or sex-determinant fibers of the cell nucleus. Certain animals and plants transmit male characteristics to the female descendants, while the female transmits her characteristics to the male descendants. There are many variations of this kind. These strange movements in heredity are explained by the laws governing chromosomes and idio-chromosomes and elementary cells.

According to the germ plasm theory of inheritance, the separate parts of living organisms are assumed to be represented by separate material particles in the germ cells. In the Mendelian theory each cell is assumed to contain a large number of ids, or complete sets of sex determinants, half the total being derived from each parent. This permits the germ cells to contain a certain number of ids from each parent.

Studies of these subjects show that the great harmonies of the natural world are manifested in form, number, pattern, and color, which we find to be basically simple and, when studied systematically, they appear quite clearly, so as to be capable of being described and expressed as laws.

The study of the agencies under social control which may improve, or impair, the racial qualities of future generations, either physically, socially, or mentally, is called the science of eugenics. This new science is another outgrowth of the revolution in intellectual development originating with the publication of Darwin's theory. Sir Francis Galton was the pioneer worker, and he has been followed by Pearson, Yule, Lombroso (1836-1909), and others.

Eugenic studies, confirmed by those of genetics and biometry, show that the human race, which is the masterpiece of Nature's evolutionary processes, is capable of much further development through the careful guiding of the very forces used in evolving man to his present state. Man can be improved by selection and education to greater beauty, clearer intellect, larger stature, sounder character, and better physique. The measure of what man has done is a good criterion of what he is capable of doing under the guidance and encouragement of science.

Genetics, the study of the hereditary phenomena of organisms, is based upon the law of inheritance discovered by Mendel in 1865. This law relates to the inheritance of certain definite characters called allelomorphs. These characters are found to group themselves in pairs which exhibit more or less antagonistic qualities. A knowledge of these characteristics is necessary to conduct selective breeding experiments scientifically. It is found that when two similar germ cells, each bearing the same new combination of allelomorphs, meet in fertilization, they result in the development of a new zygotic combination of a pure type which breeds true. This accounts for the establishment of new species. When, on the other hand, the coupling is unequal, or only partial, there will be irregularities in the characters of the offspring and no new species is likely to develop. Immense value is attached to this law by naturalists working in all fields. The three new sciences of eugenics, genetics, and biometry have prepared the way for a regeneration of humanity through breeding in the desirable and breeding out the undesirable.

CHAPTER XIII
CHEMICAL AND BOTANICAL THEORIES

The World War served to demonstrate the degree of perfection which has been attained in chemistry. The wonderful high explosives used, the poisonous gases, the lubricating and motor oils and a multitude of valuable chemicals employed for military and naval purposes, many of which were developed at short notice, showed the modern chemist's command of his science. Yet chemistry is a new science. Practically it began with Robert Boyle, in England, in 1661. Boyle conducted experiments on the rarefaction of air and the nature of gases, and in his book, "The Sceptical Chemist," he made this remarkable statement: "I am apt to think that men will never be able to explain the phenomena of nature, while they endeavor to deduce them only from the presence and proportions of such or such ingredients, and consider such ingredients or elements as bodies in a state of rest; whereas, indeed, the greatest part of the affections of matter, and consequently of the phenomena of nature, seem to depend upon the motion and contrivance of the small parts of bodies."

Thus Boyle anticipated the chemical theories of matter developed in the nineteenth century.

Lavoisier, about 1777, advancing from the quantitative study of one chemical change to another was able to describe many processes, and to distinguish between an element and a compound. He cast aside all the alchemical formulæ and expressed the results of his experiments in fractions and proportions.

J. B. Richter between 1791 and 1802 made a series of experiments by which he secured the weights of various bases neutralized by constant weights of several acids, and the weights of several acids neutralized by constant weights of several bases. He found that the composition of chemical compounds is constant, as had been assumed by Lavoisier and Boyle.

Dalton described the atomic constitution of gases in 1808, and sketched the law of multiple proportions in chemical combinations and described binary, ternary and quaternary combinations.

Prussic acid was investigated by Gay-Lussac in 1815, when he isolated cyanogen and found that although it is a compound it plays the part of an element with hydrogen and the metals. Berzelius also found that ammonium possessed all the properties of an alkali metal.

Ten years after the above discoveries were made, Faraday prepared a compound of carbon and hydrogen from liquefied coal gas which led to the general study of isomerism and the great discoveries of the organic radicals with their important combinations.

When isomeric combinations were studied by Jacob Berzelius (1779-1848), he was led to devise a means of expressing organic reactions. He wrote to Wöhler and Liebig a letter outlining his new method in which he said: "From the moment when one has learned to recognize with certainty the existence of ternary atoms of the first order which enter compounds after the manner of simple substances, it will be a great relief in the expression of the language of formulæ to denote each radical by its own symbol, whereby the idea of composition it is desired to express will be placed clearly before the eye of the reader."

Photo, Fifth Avenue Hospital

ROOM IN WHICH INFECTED ARTICLES ARE STERILIZED

MODERN OPERATING ROOM IN A PARIS HOSPITAL. IT IS FITTED WITH A GLASS DOME AND RADIO MICROPHONES FOR THE USE OF STUDENTS AND DOCTORS WHO WISH TO WATCH THE OPERATIONS AND HEAR DISTINCTLY THE COMMENTS OF THE SURGEONS

An example of this method of expressing reactions was given in the case of the action of chlorine on benzoic acid. He wrote B_2O for benzoic acid, B_2CL_2 for chlorbenzol and B_2 + NH_2 for benzamide. With certain simple improvements made subsequently by Gmelin, the method devised by Berzelius was generally adopted and is in use to-day.

The numerous investigations now being made with the object of discovering the various combinations of the elements led to many improvements in chemical analyses. When we read Berzelius' accounts of his analyses they seem to have been written only yesterday. He and his contemporaries developed analytical and synthetic methods to almost the efficiency that we see to-day.

We also owe to Berzelius a table of the elements showing their electrical qualities, an electrochemical theory, identifying chemical affinity with electric attraction, and a new nomenclature, besides a vast amount of descriptive chemistry.

The discovery of the specific heats of various solid elements by Dulong and Petit in 1819, and Mitscherlich's finding of the isomorphic phenomena in 1818, resulted in the publication of a new atomic weight table in 1826 by Berzelius.

The experiments made in isomorphism by Mitscherlich led him to discover dimorphism and study crystallography. He used his knowledge of crystal measurement extensively and developed synthetic chemistry and the laws of crystallization.

Thompson, Prout, and Wollaston were working on problems in England similar to those examined in Sweden by Berzelius and Mitscherlich.

Molecules were discriminated from atoms in 1826 by Jean Baptiste Dumas and Faraday discovered his law of electrochemical action in 1834.

Organic chemistry originated in Manchester, England, when Dalton read his paper before the Manchester Philosophic Society in 1803 on the theory of atomic weights. This paper led Gay-Lussac, Thenard, Berthollet, de Saussure and others to study organic analyses as devised by Dalton. Gay-Lussac and Thenard greatly improved Dalton's methods and in 1824, as shown by Chevreul's work on fats and greases, organic analyses had been brought to high perfection.

The phenomena of substitution in hydrocarbon compounds like the petroleum oils were studied by Laurent who proposed a theory of basic nuclei. C_10H_8 being the nucleus of the naphthalene group and C_2H_4 that of the ethylene group, derived nuclei can be obtained from these by substitution and hydrogen and other elements acting on derived nuclei from numerous hydrocarbon series.

The homology of the hydrocarbons was discovered by Gerhardt in 1844 while he was investigating the alcohols. Wurtz's work on the ammonia compounds, Williamson's on the ethers, Hoffmann's on anilines, Graham's and Liebig's on the citrates, and Frankland's, Kolbe's and Kekulé's work on other compounds raised organic chemistry to such a high plane that industrial chemists were able to use their theoretical conclusions and build a great number of important industries upon organic principles.

Lothar Meyer, in 1868, and Mendeléeff, in 1869, published atomic weights showing improvements in the theories of valency and the interrelationship of atomic weights. Mendeléeff was able to predict from the vacant positions in his table the discovery of important new elements. A number of these elements have since been discovered.

The aniline dye industries have grown out of the discoveries of many chemists. The basic work was done by Faraday, Laurent, and Runge, who isolated valuable hydrocarbons from coal gas tar. Hoffmann discovered aniline and Perkin obtained mauve in 1856 by the oxidation of aniline with chromic acid. It was this and subsequent discoveries by Perkin which gave the greatest impetus to synthetic dyes. The solubility of a dye was improved by increasing its acidity (sulphonation) or by increasing its alkalinity (alkylation). Similar dyes are now made by the same methods from many common aromatic substances.

The chemistry of explosives was developed by Van Helmont, Debus, Bunsen, Abel, Nobel, and, others. Fulminates were used for detonators by Ure in 1831, picrates were employed as explosives by Fontaine and Abel; nitrocellulose (guncotton) discovered by Braconnot in 1832 and used as an explosive by Schönbein in 1846, and nitroglycerine was produced by Sobrero in 1847. Smokeless powders made from guncotton, dynamite, and gelatine were introduced by Nobel in 1890.

Pasteur showed, in 1848, that when the double sodium ammonium racemate was crystallized, two kinds of crystals separated from the solution. When one set of crystals was dissolved in water the solution rotated a beam of polarized light to the left, while the aqueous solution of the other crystals rotated the light to the right. These crystals thus revealed their geometrical properties with perfect light while in solution in water. Pasteur noted that optical activity of this kind is the expression of some form of molecular asymmetry.

Le Bel in 1874 also pointed out that optical activity is an expression of the asymmetry of the chemical molecule and showed that all carbon compounds which are optically active contain a carbon atom combined with four different atoms, or groups. Van't Hoff showed in 1875 that there were definite relations between the arrangements of tetrahedral carbon atoms and polarization phenomena and established the theory of such atoms.

Willard Gibbs, of Yale, discovered what is known as the phase rule, which shows, by thermodynamic methods, how the conditions of chemical equilibria can be systematically grouped.

Van't Hoff, Pfeffer, and others noticed that when two solutions are brought together, if one is more concentrated than the other, diffusion begins in the concentrated and extends to the weaker solution. This shows a talent force in concentrated solutions which is now known as osmotic pressure. Van't Hoff and Arrhenius showed that for comparable concentrations the osmotic pressure of a solution is exactly equal to the pressure of a gas. These discoveries led to a brilliant series of investigations into electrolytic chemistry.

The theory of electrolytic dissociation advanced by Ostwald shows that the molecules of electrolytes in aqueous solutions are broken down into electrically charged parts called ions. In very dilute solutions the dissociation of strong acids, bases, and salts is practically complete as was suggested by Williamson in 1851.

Catalysis, or reaction brought about by agents which do not enter into the chemical changes, was discovered by Berzelius. Ostwald investigated and developed catalytic reactions which are now extensively employed in industry, particularly in refining oils and in the fixation of nitrogen. Hot platinum, for example, is used to act catalytically in causing sulphur dioxide and oxygen to combine and form the basis of sulphuric acid, sulphur trioxide.

One of the most important applications of catalysis to industry is the Haber process for securing nitrogen from the air. When air and hydrogen are compressed and heated to a high temperature in the presence of a catalyzer such as metallic uranium or iron carbide, the nitrogen and hydrogen combine and form ammonia.

The experiments of Sir William Crookes on vacuum tubes subjected to electrical impulses led the way to the discovery of radioactivity, and investigations of radium have revolutionized our conceptions of the nature and properties of matter.

The discovery of helium, argon, the niton emanation from radium and other elements by Ramsay, Collie, Soddy, and others will be referred to later.

Carl Linnæus, who is called the father of modern botany, established the genera and species of plants upon philosophical principles. He established a binomial nomenclature and formulated modern descriptive methods. Thus he prepared the way for the systematic works of De Jussieu and De Candolle.

De Candolle, in 1819, published a new method of classification based upon morphological characters. He defined and illustrated the doctrine of the symmetry of plant organs and asserted that a natural classification must be based on a plan of symmetry.

The relationships between the endosperm and embryo were shown in 1810 by Robert Brown in his monograph on the Australian Proteaceæ. The morphological nature of seed reserves was described by him. He also discovered the functions of the cell nucleus and founded cytology. He showed that the oscillation of minute particles in the fluids of plants when viewed under high microscopic powers, known as the Brownian movement, is due to purely physical causes.

Schultze, Unger, and others, working on suggestions previously made by Knight, Robert Brown, and Hooke, discovered the rôle of protoplasm in plant cells. Alexander Braun and De Bary correlated the movements of protoplasm with the locomotory movements of free zoögonidia and the amœboid movements of Mycetozoa. These investigations directed research to further studies of the structure and constitution of protoplasm and helped develop the cellular theory.

The Algæ were studied and classified by Naegeli, Unger, Von Mohl, Haustein, and others in 1847-1850.

The vascular cryptogams were studied by Hofmeister. He found that the alternation of a sexual with an asexual generation is common to all plants of the mosses, vascular cryptogams, and gymnosperms, as well as among angiosperms.

Hofmeister's work led to appreciation of the fact that a natural system of plant classification must be based, not on balancing the values of the morphological parts of fruits and flowers, but on the anatomy of the real and concealed reproductive organs.

Fossil botany, or paleophytology, was founded, in 1828, by Adolphe Brongniart. Witham, Goeppert, Unger, Corda, and others helped to advance this science.

The publication of Darwin's "Origin of Species" in 1859 found the various botanical sciences already well worked out by numerous capable experts. A huge amount of data and descriptive matter had been assembled and botany, like the other sciences, was ready to be quickened by the Darwinian theories.

The idea of a progressive evolution in plants had been suspected by many botanists, but the genius of Darwin developed it. Living plants were pictured as a multitude of units competing for food, light, air, and room for growth, and struggling against unfavorable environments. The classification of tissues was begun, and the phenomena of absorption of water and salts, the ascent of sap, the absorption of minerals and nitrogen, and metabolism and growth were elucidated. Investigations were made into the nature and functions of chlorophyll and other plant substances. These studies resulted in suggesting means for improving crops by artificial selection, as shown in the work of Luther Burbank.

CHAPTER XIV
GEOLOGY, METALLURGY, AND METEOROLOGY

Geology is essentially a nineteenth century product. Fossils, minerals, rocks, and rock strata had attracted more or less attention from the earliest times. The Egyptians, Greeks, and Romans had books dealing with such subjects, and Greek philosophers, like Aristotle, lectured upon them. But it was only in the last century that geology was placed upon a scientific basis and began to make progress. The reformation was begun by Cuvier's work on paleontology, the chemical and physical discoveries of the eighteenth century, and the works of Hooke, Boyle, Buffon, Linnæus, and others. The special technique required in geographical research could not be developed until the biological, anatomical, botanical, and physical sciences had been established on a scientific plane. That is why geology remained for so many centuries undeveloped, and then rapidly advanced during the nineteenth century. Its preparation was long and involved, while its fruition was rapid and brilliant.

William Smith (1769-1839), called the father of English geology, was a mining surveyor engaged in making colliery and farm surveys in Oxfordshire and the west of England. His professional work led him to study the coal outcrops, and in 1793 he mapped the inclined coal deposits in Somersetshire. The numerous rock strata accompanying the coal beds contained fossils which he found could be used to identify the beds in that field with others in northern counties. He published an account of this manner of using type fossils for identifying fossiliferous rock formations in 1799, and in 1815 issued his geological map of England, Wales, and southern Scotland. This map showed the advantages that scientific geology and mineralogy offered to industry and caused scientists all over Europe to study geological phenomena and make sketch maps of local geology.

A work on paleontology, dealing with the fossils of the Old Red Sandstone deposits, published in England by Hugh Miller (1802-1856), which had an enormous popularity and has been described as the most fascinating book ever written on a geological subject, followed Smith's "Strata Identified by Organized Fossils." A large amount of mapping resulted from the issuing of these two works. These maps called for detailed descriptions, and these in turn resulted in the accumulation of many interesting data which, when collected, and systematized, led to many important discoveries.

While these authors were preparing their books, Werner, De Luc, De Saussure, Lamarck, and others were working out paleontological problems, Romé de l'Isle, Brongniart, Haüy, d'Aubuisson, and others were building up the science of mineralogy.

"The Theory of the Earth," of Dr. James Hutton (1726-1797), was published in 1785, and in an enlarged form in 1795. This book described the metamorphoses of sand into sandstones, quartzites, schists, and other rock formations; the work of floods and lava floods; the sculpturing powers of streams, rains, and winds, etc. He indicated the effects of the alternate sinking and raising of strata through earth shrinkings and volcanic phenomena, and taught that purely physical causes can be found for every geological effect.

Playfair's "Illustrations of the Huttonian Theory of the Earth" augmented the teachings of Hutton's book, while works by Jameson, Kirwan, Boué, Sir James Hall, Daubrée, St. Claire-Deville, Buckland, Sedgwick, Bakewell, Breislak, Maclure, and others rapidly appeared sustaining the Huttonian, or the Wernerean theories of geological deposition.

The work of James Sowerby (1757-1822), entitled "The Mineral Conchology of Great Britain" and that of James de Carle Sowerby (1781-1871), published between 1812 and 1845, marked the establishment of paleontology as a science. Both father and son were well-trained naturalists and artists, and, like William Smith, reproduced the fossils and their containing rocks to scale and in natural colors. These works greatly simplified the labors of field geologists in identifying rock strata and type fossils.

In Germany geology was worked out by Baron von Schlotheim (1764-1882), Goldfuss (1782-1848), and Count Munster (1776-1844). Brocchi (1772-1826) described Italian fossil strata.

The "Geological Classification of Rocks," of MacCulloch, marked the separation of petrology as a science from descriptive geology. MacCulloch noted that the ancient granites and granite schists are among the oldest rock forms.

Von Humboldt, Murchison, Lyell, De la Beche, Von Buch, Elie de Beaumont, Holley, Geikie, Bonney, Wollaston, Scrope and Daubeny were among the pioneer geologists in Europe, while James Dwight Dana (1818-1895), E. S. Dana, Conrad, Hitchcock, Warren, Lesley, Fremont, and others published descriptive geological accounts in the United States.

References to the geology and minerals of New Mexico were made in Humboldt's "New Spain." Greenhow's work on Oregon and California, published in 1845, and Lewis and Clark's reports added much to our knowledge of American topography and geology. These reports were followed by those of Stanton, Clarence King, Hague, Emmons, Custer, Powell, Davis, Gilbert, Agassiz, and others which dealt with various phases of American geology, paleontology, glaciation, and mineralogy, and prepared the way for the publication of the valuable works of Dana, Williams, Iddings, Washington, Pirsson, Clarke, Grabau, Brush, and others.

The treatment of geological problems from the viewpoint of present causes was begun after the publication of Lyell's "Principles of Geology" (1830-1833). Earlier geologists were aware of the fact that many of the rock formations had been derived from other consolidation of sand and mud beds and by other actions which may be studied in operation to-day. But the systematic manner in which Lyell treated the whole field of geology made such an impression upon geologists that the publication of his great work marked a new era in the science. De la Beche, Buckland, Geikie, Bonney, and other geologists in England; Dana, and a number of scientists in the United States Geological Survey, in America; Vogt and Naumann, in Germany; Studer in Switzerland; Stopanni, in Italy, and many specialists in other countries took up the work of Lyell, and at present practically every important geological factor is known and the effects of its operations have been described.

The succession of life in geological periods is studied under paleontology. This science developed at the same time as systematic and descriptive geology. Many great naturalists have contributed to it. Agassiz, Hall, Dawson, Walcott, Marsh, and others in the United States and Canada; Owen, Prestwich, and others in England; and numerous writers in Europe have published valuable monographs on various phases of fossil and strata-graphical geology.

Paleontology, by fixing the succession of animal and vegetable eras, has served as a basis for measuring time, revealing the antiquity of man and of the principal mammals, as well as showing changes in climate, and in land and sea areas.

The application of geology to many industries called forth another branch of the science known as economic geology. This deals with the origin and geographical distribution of the useful minerals, the derivation of underground waters and petroleum, and the changes undergone by soils.

The first important impetus to economic geology was given by the publication of Whitney's "Metallic Wealth of the United States" in 1854, Von Cotta's work on ore deposits in 1859, and the economic references in the textbooks of the leading European and American geologists. The recent work of Bonney, Groddeck, De Launay, Phillips, Prosepny, Van Hise, Emmons, Le Conte, Lindgren, and others has greatly advanced the interest and usefulness of the science.

These writers carried out an extended series of investigations on the depth temperature and physical and chemical condition of the earth's crust. Chemical analyses of rocks and soils were made and the changes wrought by physical and chemical forces were noted. On these were based theories as to the formation of rocks, soils, minerals, and ore deposits. The erosive properties of soil water were found to be limited to a depth not exceeding 20,000 feet, although hydrostatic water bodies are rarely found as low as half that distance, the rise in temperature precluding their existence. The work of these men revealed the part played by vulcanism in rock changes, and the effects produced through hot solutions and magmatic intrusions.

Various systems of classification of minerals and ore deposits were developed. Richard Beck's, "The Nature of Ore Deposits" (1900), and Lindgren's "Mineral Deposits" (1919), are works which have contributed to the systematizing of economic geology from the mineral standpoint, and the establishment of epochs of metal generation.

The ore deposits of the United States have been described in the monographs of the United States Geological Survey, and by Kemp, Spurr, Grabau and other writers.

This branch of geology emphasizes the strong tendency to concentration shown by mineral elements. All climatic forces are found to aid this work. Underground waters, both flowing and stationary, are powerful assistants.

Other phases of economic geology have been developed in studies of subterranean waters, microscopical petrology and mineralogy, the chemical analyses of rocks, etc. Among the leaders in this work have been Pirsson, Emmons, Iddings, Washington, Van Hise, Clarke, and others.

The enormous metallurgical industries of to-day are all dependent upon scientific principles chiefly discovered and applied in the nineteenth century.

Metallurgists in the previous century knew that by adding certain metals to molten steel it could be hardened. A method of this kind was published by Réaumur in 1722. Tool points, he showed, could be hardened if the steel when red hot was forced into solid tin, lead, copper, silver or gold, thus producing an alloy stronger and harder than the pure steel.

A series of calorimetric researches on metallic alloys, carried on by Bergman, led to the discovery that steel differs from iron merely in the carbon contents. Clouet, in 1798, followed this by an experiment in which he melted up a little crucible iron with a diamond and obtained a mass of steel. This created a sensation and led to many other experiments on the metallurgy of cast and wrought iron and steel.

Thomas Young, in 1802-7, studied the mechanical properties of iron and steel and developed the theory of the modulus of elasticity. A patent was issued to the Rev. Robert Stirling, in 1817, for a regenerative iron smelting furnace. The next year Samuel Baldwin Rogers substituted iron bottoms for sand bottoms in puddling furnaces. Faraday and Stodart produced the first alloy of nickel and steel in 1820, and in 1822 Faraday showed that there is a fundamental chemical difference between hard and soft steel.

The first patent for a hot blast for iron furnaces was granted to James Beaumont Neilson in 1828. All these discoveries led to important improvements in iron making.

The steam hammer was patented by Nasmyth in 1842, and between 1843 and 1848 Thomas Andrews conducted valuable investigations into the heat of combination.

The ground was now prepared for one of the greatest of metallurgical inventions—the conversion of pig iron into steel by an air blast in a Bessemer converter. This invention not only vastly extended the use of steel, but drew attention to the valuable oxidizing effects of a hot air blast and in that way induced many important improvements in the metallurgy of copper, lead, and zinc.

Siemens, Whitworth, Bell, Graham, Percy, Richards, Martin, Thomas, Holley, Hewitt, Fritz, Howe, Jones, and others made further important improvements in the metallurgy of iron and steel in the United States and Europe.

One of the early American iron smelters was built by Governor Keith, in 1726, in New Castle County, Delaware. A rolling mill and forge were subsequently built at Wilmington. The first American smelted iron was shipped to England from smelters in Maryland and Virginia in 1718. The Bessemer steel process was introduced into the United States by Abram Hewitt at the Troy smelter, New York, in 1865. From these beginnings the iron industries of the United States have grown so that they now produce more than two-fifths of the world's annual supplies.

The alloys of iron and steel have now attained importance and a new science known as metallography has developed. Professor Arnold, of Sheffield, Sherard Cowper-Coles, Roberts-Austen, Sorby, Tschermak, Tschernoff, Wüst, and Ziegler have been active promoters of this branch of metallurgy, and a closely related one dealing with the effects of the heat treatment of metals.

Developments in the iron industries led to others in the metallurgy of copper, lead, and zinc.

The application of the blast furnace to copper, lead, and zinc smelting was chiefly made in America. One of the early furnaces was built in Leadville, Colorado, in 1877. From that time, pyritic smelting has been chiefly developed by American metallurgists. The metallurgy of lead, copper, and zinc has reached a similar high plane to that attained by iron and steel.

The metallurgy of gold and silver began to improve after the discovery of the Californian deposits in 1848. The stamper battery and amalgamation processes were improved; when sulphide ores were encountered, chlorination processes were developed. Subsequently, in response to demand for a cheaper chemical solvent for low-grade ores, the cyanide and bromide processes were devised.

The application of the electric furnace to metallurgy greatly increased the scope of metallurgists' methods.

Pichon, in 1853, described a small arc furnace with which he was experimenting, and in 1878 Sir William Siemens built a furnace for reducing iron ores. Moissan made numerous tests of furnaces and smelting methods in the nineties and did much to develop commercial electric smelting. Faure, Cowles, Borchers, De Chalmont, Girod, Heroult, and others invented furnaces, smelting methods, and metallurgical processes. The aluminum, carborundum, acetylene, and other important industries are developments from the electrometallurgy of iron and copper. Zinc, copper, nickel, silver, gold, and platinum plating and the electrodepositing of copper in the form of tubes by the Elmore process are dependent upon the principles of electrometallurgy as is the electrorefining of metals.

Copyright, Keystone View Co.

EDOUARD BELIN AND THE TELAUTOGRAPH, WHICH TRANSMITS PICTURES BY WIRE

LEE DE FOREST, INVENTOR OF THE OSCILLATING AUDION

AUTOMOBILE WITH RADIO EQUIPMENT FOR LISTENING IN EN TOUR

The physical phenomena of the earth's atmosphere are studied under the science of meteorology.

The art of weather forecasting is as old almost as mankind, but only in recent years has it been placed upon a sound basis.

Torricelli, in 1643, invented the barometer; Boyle, in 1685, developed it and applied it to measuring gas pressures. The chemists of the eighteenth century, Boyle, Black, Rutherford, Priestley, Scheele, Lavoisier, and Cavendish, all studied the chemistry of the atmosphere. Franklin, in 1749, raised thermometers by kites to measure temperatures. Balloon ascents were made by Jefferies and Blanchard, in 1784, for atmospheric observations. Soundings of the upper air by balloons, kites, and other apparatus have been conducted since the closing years of the nineteenth century.

CHAPTER XV
MEDICINE AND PHARMACY

Medicine was in a state of transition at the beginning of the nineteenth century. The great scientific discoveries of the eighteenth century had carried people away to such an extent that they showed a tendency to exaggerate their bearings upon medicine. The result was a wild diffusion of extravagant speculation and unsubstantial hypotheses.

One of the leading physicians of the eighteenth century, who wielded broad influence throughout Europe, was Herman Boerhaave (1668-1738). His work, entitled "Aphorismi," published in Leyden, 1709, was immensely popular. It was translated into all the European and several Asiatic languages. His reputation now depends upon his chemical discoveries and his medical teachings.

One of the most brilliant students of Boerhaave's medical school was Albrecht von Haller (1708-77). Haller published many medical works and monographs. His "Elements of Human Physiology," (1759-66) is the best known. The function of bile in the digestion of fats, the demonstration of Glisson's hypothesis that irritability in an excised muscle is a specific property of all living tissues, and several theories explaining the heart's activities, were among his best contributions to medical science.

The discovery of the existence of lacteal and lymphatic vessels in birds, reptiles, and fish brought William Hewson into prominence and secured him membership in the Royal Society. He published his monograph on the coagulation of the blood in 1771.

William Cumberland Cruikshank (1745-1800) investigated the surgery of the nerves, the functioning of the Fallopian tubes, the physiology of absorption.

The electrical discoveries of Galvani, Volta, Benjamin Franklin, Henly and others caused much experimenting with the electric current in the treatment of muscular diseases.

The Monros, father, son and grandson, by their wonderful teaching abilities, caused the medical teaching center of Europe to be transferred from Leyden to Edinburgh in 1720. These men, and many of their students, did brilliant work in all branches of medicine.

The medical school which they so established in Edinburgh University still maintains its great reputation.

The best anatomists of the eighteenth century were Cheselden, Pott, the Monros, the Hunters, Desault, and Scarpa. Their work was largely topographical. Surgical anatomy started with the writings of Joseph Lieutaud (1703-1780), Albinus, Eisenmann, Soemmering, Mascagni, Sandifort, and Caldani.

The anatomical textbooks in use in the year 1800 gave general accounts of the body's structure and included current theories of the functions of organs and their relationships to injuries and disease. More than half of the chapters were occupied with morbid anatomy and the recital of cases. The anatomy of the tissues and finer structures was neglected because the microscopes of the period were little better than simple lenses.

Physiology was studied by all medical students, but the science was so badly developed that it never stood alone. For many years it formed a part of studies in anatomy. Early in the nineteenth century it began to expand, and in 1846 physiology was taught as a separate subject for the first time at Guy's hospital, London, by Sir William Gull. Before that it was taught by the professors of midwifery. It was the great developments made in chemistry and physics, referred to in previous chapters, that pushed physiology to the front as an important branch of medical science.

Denman's "Introduction to the Practice of Midwifery," the work of the greatest living authority at the time of its publication in 1805, shows that gynecology hardly existed at that time.

Anesthetics and antiseptics, together with the systematic employment of abdominal and bimanual palpation, all were revolutionary discoveries of the nineteenth century, unknown when Denman presided over the obstetric department of the Middlesex Hospital.

When the nineteenth century opened, medical men were unaware of the value of auscultation and percussion. They were familiar with the symptoms of fevers and with diseases of the heart and chest, but they had no means of determining differences between them. Textbooks of that time show that the now common forms of heart disease were known only from post-mortem inspections. But they distinctly state that physicians were unable to determine, in case of changes in stricture of the heart's valves, what part was affected. The seat of disease in heart and chest troubles could not be located.

Parasitology was no better advanced. Books published as late as 1810 indicated that parasites, like hydatids, threadworms, etc., were very puzzling phenomena to the physician.

The status of surgery throughout the eighteenth century was very low. The best work was done in France and Holland, until Cheselden, the Hunters, the Monros, and Abernethy established their schools in England and Scotland. German medical practitioners were barbers until after the army authorities formed the Medico-Chirurgical Pépinière in Berlin in 1785. There were several good medical schools in the United States in 1800 including those of the King's College, New York, and of the Harvard, Dartmouth, and Philadelphia Colleges, and the University of Pennsylvania. There were also numerous medical societies. European medical and surgical textbooks were used like those of Cheselden, Monro, Haller, Boerhaave and Sydenham. Medical practice was on the same plane in America as in Europe. There were many patent remedies used, but the authorities recognized the importance of regulating the practice of medicine. Regulation acts were passed in New York City in 1760, New Jersey in 1772, and a general quarantine act was enacted by Congress in 1799.

The modernization of medicine was brought about to a large extent by the publication of the "Conservation of Energy" by Helmholtz, in 1847, and Darwin's "Origin of Species," in 1859. These books cleared away completely the myths and legends which had surrounded medicine at earlier periods, and taught medical students the strict need of proceeding entirely upon scientific grounds precisely as chemists, physicists, engineers, and others were already doing with wonderful success. Darwin's biological teachings appealed very strongly to medical men and influenced all their activities.

Virchow's "Cellular Pathology," published in 1858, Huxley's textbooks on "Physiology" (1866) and on "Vertebrate and Invertebrate Anatomy" (1871-77) Haeckel's "General Morphology" (1866), and numerous medical encyclopedias and textbooks on practice and special diseases were the result of the new scientific spirit. New medical associations were formed and these promoted discussions, the reporting of observations, and the publication of innumerable monographs. Medical journals and magazines of a high character did fine educational work.

The investigations on fermentation and putrefaction made in France by Pasteur caused Joseph Lister, professor of surgery at Glasgow University, to reflect upon the great mortality witnessed daily in the hospitals from pyæmia, erysipelas, tetanus, septicemia, gangrene, and other similar diseases. He observed that in spite of his great care to maintain scrupulous cleanliness in treating wounds, 45 per cent of his surgical cases were mortal. Pasteur's dictum that putrefaction is a micro-organic phenomenon, caused Lister to experiment with the view of preventing the development of microorganisms in wounds. Beginning with weak solutions of zinc chloride and zinc sulphite, he accidentally tried carbolic acid, securing surprising results, and two years later, in 1867, he published his monograph on antiseptic surgery which instantly became world-famous. Lister, instead of being carried away by the celebrity he attained, turned his attention to the scientific development of his important discovery. He investigated lactic-acid fermentation, the relation of bacteria to flesh inflammations and to the best methods of treating wounds antiseptically.

Lister, however, was not the first to employ antiseptics in the treatment of wounds, and his great contribution to medical practice was due to the systematic manner in which he experimented. He was not a brilliant surgeon, but a deliberate and careful one whose chief desire was to have the patient recover. His whole surgical career was guided by this principle which proved so successful that before his death the whole medical profession saluted him as master, and when he died, rejoiced that his remains were entombed in Westminster Abbey.

Theodor Billroth was one of Lister's greatest disciples. He introduced Lister's methods into continental surgery and through their use improved the treatment of wounds and opened up new fields in the surgery of the alimentary tract. He was the first to make a resection of the esophagus and pylorus and to excise the larynx.

Mikulicz-Rodecki, a Pole, was Billroth's chief assistant. He was also a pioneer in Lister's practice. Specializing on the surgery of the alimentary organs, he promoted antiseptic methods and introduced the modern modes of exploring the esophagus and stomach. He was also a master in the treatment of diseases of the mouth.

Felix Guyon applied Lister's system to surgical treatment of the genitourinary ailments, and became a leader in this class of surgery. Bernard Naunyn, a well-known German writer on surgery, became a leading authority on diabetes and diseases of the liver and pancreas. Jean Martin Charcot made the Salpêtrière Hospital, Paris, the greatest of the world's neurological clinics. He was also a great authority on diseases of the biliary passages and kidneys. Sir James Paget, Sir Jonathan Hutchinson, Sir William Gull, Jenner, Wilks, Spencer Wells, and Clifford Allbutt, besides doing much by their writings to advance the practice of medicine, all closely allied themselves with large hospitals, giving as much attention to the hospitals as to the treatment of disease. Modern hospitals are largely due to their pioneering work.

Louis Pasteur's studies in fermentation led to the discovery of lactic-acid bacteria and this was the starting point for a number of revolutionary discoveries in bacterial diseases. Infectious diseases were placed in new categories by his work.

The etiology of traumatic infectious diseases was advanced by the researches of Robert Koch (1843-1910). His work in discovering the cholera vibrio, the microorganisms of Oriental ophthalmia and his researches on the nature and treatment of tuberculosis, made his name known everywhere. His isolation of the tuberculosis germ in 1882, and that of Asiatic cholera in 1884, were leading steps toward the discovery of a great number of disease germs.

Fevers, like typhus, typhoid, yellow fever, and malaria, a few generations ago, took a great annual toll of lives. The work of the men mentioned above, Lister, Pasteur, Koch, and the French physiologist, Claude Bernard, gave medical men the means of curbing the ravages of these diseases so that to-day they are incidental annoyances rather than human scourges.

The germ of typhoid fever was discovered in 1880 by Eberth. The cocci of pneumonia were isolated by Frankel in 1886.

Modern surgery has been greatly facilitated by the employment of numerous anesthetics, chemicals which possess the power of inducing local or general insensibility. Soporific drugs have been used in surgical operations since the remotest antiquity, but modern practices in the employment of anesthetics followed the discoveries of Faraday in 1818. He described the properties of nitrous oxide, or ether and other gases in that year and suggested their use in medicine.

John Godman (1822), James Jackson (1833), and Drs. Wood and Bache (1834) were among American medical men who made use of Faraday's suggestions. Dr. Horace Wells, a dentist at Hartford, Connecticut, used ether in 1844. Two years later W. T. Morton, a dentist in Boston, employed it successfully. Chloroform was described as a useful anesthetic by Dr. Flourens, of Paris, in 1847, the year in which Sir James Simpson introduced ether as an anesthetic in obstetric practice.

Mesmer introduced hypnosis into medical practice about 1777, and in 1784 Benjamin Franklin reported favorably on the medical value of what he called magnetic sleep. Alexandre Bertrand, about 1831, described the nature of hypnosis and in 1841 James Braid employed it in his English medical practice. The employment of hypnosis has not become general, although it is recognized that in certain nervous troubles there is a field for it.

Among other American medical men who advanced their science in the past were James Marion Sims (1813-1883) and Thomas Emmet, who acquired wide fame for successful methods of operating in obstetric diseases. William Beaumont (1785-1853) investigated the offices of the gastric juice and devised treatment for digestive troubles. John Shaw Billings served his profession by compiling, with the assistance of Robert Fletcher, an Index Catalogue of the Surgeon General's library, Washington.

Pharmacology is as old as medicine. The medicinal qualities of herbs, roots, and gums were known to primitive man. There have been herbalists and druggists in all important communities at all times. Scientific pharmacology, however, is just as new as modern medicine. Cordus published a pharmacopœia, which listed drugs in use in 1535. Since that time many such works have appeared. The second of the Monros of Edinburgh University Medical School, Magendie, and Claude Bernard placed pharmacy upon a scientific basis. They followed scientific methods used by Fontana in Florence in 1765 in studying the effects of snake poisons. Pareira's "Elements of Materia Medica" was the leading textbook in 1842. This work gave very brief accounts of the physiological effects of drugs. The physiological values were not properly appreciated until about twenty years later.

Drugs are now scientifically classified and prepared, the full resources of science being used in their manufacture. American chemists have invented machinery and methods of preparing new drugs. Citrate of magnesia was invented by Henry Blair, of Philadelphia. Many other valuable remedies came from his laboratory, including sirup of phosphates.

CHAPTER XVI
ELECTRICITY AND RADIOACTIVITIES

Among the most marvelous scientific developments of the nineteenth century those in the electrical field claim universal attention. It was only as recently as 1844 that Morse introduced electric telegraphy. The telephone was introduced by Alexander Graham Bell in 1876 and Edison built one of his early dynamos in 1878 and in 1879 made his first high resistance incandescent lamp for parallel operation. The first Edison power and lighting station was opened at 257 Pearl Street, New York City, in 1882.

Although electrical phenomena were understood in a general way thousands of years ago, they were not studied and applied to practical purposes until the sixteenth century when William Gilbert carried out his classical experiments in the reign of Queen Elizabeth. The Leyden jar was discovered in the early half of the eighteenth century. From experiments carried out with these jars a great number of important inventions were derived and our knowledge of electricity was for many years dependent upon researches of this kind. Benjamin Franklin in experimenting with the Leyden jar found that its electrical discharges were similar to those of lightning and he subsequently discovered that the inner part of the jar, when charged with a frictional current, was positively electrical while the outer portion was negative.

The voltaic pile was invented in 1796 as a result of Galvani's experiments in physiological electricity and Sir Humphry Davy exhibited the first practical electrical lamp before the Royal Society in 1809. The dynamo was, in substance, invented by Faraday, and described by him before the Royal Society in 1831. This was, perhaps, the greatest of all electrical triumphs because it gave engineers a practical means of generating and using electrical currents of any desired dimensions. Bunsen in 1840 devised a means for making carbon rods for arc lamps, and Edison made practical carbon incandescent lamp filaments in 1879. Faraday's invention promoted all of these lighting discoveries.

The engine-driven electric dynamo was made a practical machine in 1870 and thenceforward became the source of power of a great multitude of secondary machines, such as electric street cars, marine engines, power plants, and forging hammers.

A new and profitable field was opened for the use of electricity by the invention of the electric furnace. Sir Humphry Davy produced his electric arc in 1808 and was greatly impressed with its fusing properties. He melted many metals with the arc and found that it fused platinum just as easily as an ordinary tallow candle melts beeswax. The electric furnace, which is now extensively used in chemical and metallurgical works, is simply a large electric arc provided with means for containing the heat. Furnaces lined with carbon are now heated to over 4,000 degrees centigrade.

When the electrical manufacture of aluminum on a large scale was started at Niagara, Dr. Edward Acheson, who was impressed by the industrial needs of cheap abrasives, accidentally discovered that by heating a piece of porcelain to a high temperature in an electric furnace and bringing it in contact with pure carbon, the carbon was rendered very hard. In 1891 he carried on experiments with high currents and a mixture of ground coke and sand. He found a method of fusing these so that the oxygen of the sand passed off with carbon in the form of carbonic acid gas, and the reduced metallic silicon combined with an equal atomic weight of carbon and produced a new body which he named carborundum. The success met with in making carborundum led to the devising of a method of manufacturing artificial graphite in the electric furnace. A soft, non-coalescing graphite was made in 1906. This is extensively used in lubricating heavy machinery.

Dr. Acheson produced the first chemically pure artificial carbon in his electric furnace in 1911. By using pressure during consolidation this carbon may eventually be converted into diamonds.

Another valuable product of the electric furnace, acetylene gas, was discovered in Dublin by Edmund Davy in 1836. Subsequently numerous chemists discovered means for making carbides. T. Sterry Hunt, an American chemist, observed in 1886 that oxides of the alkaline metals and of calcium, magnesium, aluminum, silicon, and boron could be reduced in the electric furnace in the presence of carbon and could be alloyed with other metals. He also found that silicon and acetylene could be made that way.

T. L. Wilson, a Canadian engineer, in attempting to make aluminum bronze in an electric furnace, devised an experiment for reducing lime with carbon. He found that this produced calcium carbide and secured a patent for the invention in 1892. Variations of this process are now used for manufacturing nitrogen and nitrates from atmospheric nitrogen.

Wireless developments have resulted from the work of many separate investigators. K. A. Steenheil in 1838 used the earth return in live telegraphy and suggested the possibility of wireless telegraphy. Joseph Henry produced the first high-frequency oscillations in America in 1840. Lord Kelvin in 1853 enunciated the mathematical principles governing uncoupled electrical oscillatory circuits. Joseph Heyworth patented a wireless telegraphic process in 1862. Clark Maxwell in 1867 predicted the existence of electromagnetic radiations and these were demonstrated by Hertz in 1887. Hughes discovered the phenomena of the coherer and Branby used Hughes's coherer for wireless wave detection in 1892. A. E. Dolbear secured United States patents for a system of wireless telegraphy using aerials in 1886. Sir Oliver Lodge described his wireless system before the Royal Society in 1894 and in the same year Popoff issued descriptions of his wireless system.

Wireless telegraphy became commercially practicable in 1897 when G. Marconi secured the promotion of the Wireless Telegraph and Signal Company in England. Marconi succeeded in turning to commercial account a long series of brilliant discoveries in electricity, and this success has led to numerous kindred discoveries. De Forest's three-electrode thermionic detector, known as an Audion, invented in 1907 and improved in 1911 by Lieben and Reiss, in 1913 by Meisser and in 1914 by Langmuir, opened up great possibilities for sound transmission by wireless telephony.

The electric deposition and refining of metals have been referred to in previous chapters. Many industries are based upon these. Niepce produced commercially successful photographs in 1838. Earlier, in 1824, he had etched plates for printing and in that year published his photo-engraving of Cardinal d'Amboise. Fox Talbot patented a mixture of gelatine and bichromate of potash to take the place of the bitumen used by Niepce as a plate coating. Gillot found in 1872 that Fox Talbot's method of making intaglio plates could also be used for making relief blocks. In 1885-1886, F. E. Ives sealed two single-line screws together and made a new fine cross-line screen, which resulted in the development of the half-tone process. Ives at this time also developed the three-color photo-engraving process.

Photography and photo-engraving are so widely used and are so intimately connected with our civilization that few people now realize that the great industries based upon them are the results of a few scientific discoveries of a couple of American and European scientists made only a generation or two ago.

GIFTS FOR TUTANKHAMEN BROUGHT BY HUY, VICEROY OF ETHIOPIA. THE MAN IN THE GAY COSTUME, AT THE RIGHT, MAY BE A PHŒNICIAN. (EGYPTIAN PAINTING)

TUTANKHAMEN'S TOMB—BRINGING UP THE HATHOR COUCH. THE COW WAS SACRED TO ISIS OR HATHOR OF WHOM THE HORNS WITH THE MOON DISK WERE EMBLEMS

QUEEN NEFERTITI, MOTHER-IN-LAW OF TUTANKHAMEN

This wonderful work of an unknown Egyptian sculptor represents the wife of Ahknaton, the "heretic" king of Egypt (originally Amenhotep or Amenophis IV). The original is now in the Berlin Museum.

Chemists had long recognized the fact that certain chemicals like preparations of zinc, fluorine, and phosphorus were phosphorescent. It was found early in the eighties that Welsbach gas mantles, when placed on a photographic plate and exposed in a dark room for two weeks, made a fine picture. Invisible rays in the mantle imprint its image. Röntgen, in 1895, discovered what are now known as the X-rays. This discovery was the result of experiments begun in 1859 by Plucker to ascertain the cause of fluorescence in light glass, and Sir William Crookes, between 1879 and 1885, carried out beautiful experiments on fluorescence. These were the immediate pioneers of the discovery of the cathode rays and the other great radio discoveries of recent years. Crookes, remembering Faraday's suggestions concerning a fourth state of matter, expressed the opinion, in 1885, that the matter constituting cathode rays is neither solid, gaseous, or liquid, but in a fourth state which transcends the gaseous condition. Perren found in 1895 that the rays carried electrically negative charges and Sir J. J. Thomson noticed that their velocities are appreciably less than the speed of light. Owing, however, to their great momentum, hardly anything can long endure their impacts. They fuse platinum and make diamonds buckle up into coke.

Electrons, which constitute the cathode rays, were originally studied in Crookes vacuum tubes, though they are now found to pervade the universe.

Larmor in 1897 proposed an electronic theory of magnetism.

Henri Becquerel was the first to discover radioactivity. He made radiographs from uranium salts in 1896. M. and Madame Curie undertook the investigation of uranium and found that among the minerals occurring in pitchblende, or uranium ore, bismuth and barium showed radioactive properties, whereas when these metals are found in their ordinary ores they are not radioactive. This discovery led to the finding of two new metals, polonium and radium. Radium is now obtained by fractional distillation of solutions obtained from American and Australian pitchblende.

Helium, one of the lightest substances known, was discovered in 1895 by Sir William Ramsay, and liquefied, at a temperature 3 degrees above absolute zero, or -270 degrees centigrade, by Onnes in 1908. Helium appears to be one of the ultimate products of the disintegration of all radioactive elements.

Some of the most interesting discoveries about radioactivity are very recent. Radium prepared from uranium in 1915 was found in 1919 to have increased proportionately to the square of the time interval. The amount of radium in some preparations was found to have increased ten times in four years. The old idea of the constant fluxation of matter was thus shown to have been based upon a scientific truth.

CHAPTER XVII
SCIENCE IN THE TWENTIETH CENTURY

It is obvious that we are now in a great period of transition. Scientific discoveries came so quickly at the end of the last century that a recasting and readjusting of scientific conceptions had to be undertaken. This process was in progress when the World War began. The world-wide disturbance led to temporary scientific infertility except in such directions as served the purposes of war. But therein science became allied more closely than ever before with certain branches of industry, and the cooperation thus established has been recognized in all civilized countries as of the utmost value to the future progress of mankind.

The philosophic thought of each era generally develops in harmony with social and intellectual conditions. The philosophical doctrines of the leading writers may, therefore, be taken as representative of the spirit of their age. When Darwin in the middle of the last century published his doctrines of evolution, of the struggle for existence and the influences of living conditions upon survival of species, philosophy turned away from the utilitarianism and tolerance of Hamilton, Hume, and Mill and the positivism of the French to the synthetic evolutionism of Herbert Spencer. One of the basic teachings of Spencer was the relativity of knowledge. The process of thinking involves relation, difference, and likeness. This is merely relationing. Therefore no thought can ever express more than relations. The primary act of thought through which we discover likeness and difference underlies all our knowledge.

A reaction against this new empiricism began in 1898, when William James published his "Philosophical Conceptions and Practical Results." This work popularized the philosophy of pragmatism which denies the absoluteness or ultimateness of the traditional antithesis between theory and practice and relies for its justification upon the fact that everything which we think about, and do, must first be willed. Reality consists in pure experience quite independent of thought. Bergson developed this philosophy of practicalism further and taught that knowledge of reality comes through intuition and that life is merely intuitive knowledge. Intuition, is deeper than scientific reason because it feels, and links us with, the eternal processes of nature.

Philosophic thought is now temporarily influenced by the revival of an old principle known as the principle of relativity. The popular name for this is the Einstein theory, because in 1905 Albert Einstein, working on some theories developed by Lorentz and Fitzgerald, published his first principle of relativity which suggested that the velocity of light is constant, however the position of an observer may vary and that space and time are variable. In 1917 Einstein enlarged this idea in order to include all the laws of nature.

Space and time are treated as just mental concepts. They lack the concreteness of matter, but they compose the framing of the universe and give it form and continuity. Consequently we see so much of them that we attribute reality to them. The theory of relativity suggests that time is not continuous. There is no identity of instants at different places. The present instant really does not extend beyond this immediate point. At other points there are instants older, younger, and contemporaneous with this instant. They are, however, quite distinct from this one. In order for an instant to be simultaneous it would be necessary that it should occur at the same point.

An object or event gains its substance and form from activities of our minds. Any meaning or significance that an object or event has is also derived from our minds. The reality of the universe is an activity, or series of activities, which are manifested in life and mind.

The relativity of space is illustrated by an example given by Professor Henri Poincaré. Assume that I meet you in Wall Street, New York, and say, "I will meet you here again at this time to-morrow." You promise to do so. But you could not keep such a promise except with regard to position on the surface of the earth, because between now and to-morrow the earth will have moved over an enormous distance carrying Wall Street and a great mass of other things with it. The sun also will have moved away the stars, carrying the earth with it.

Another interesting mental picture is drawn by Professor Herbert Wildon Carr to illustrate the philosophical meaning of the principle of relativity. Suppose that on a very frosty morning we were to see a watery vapor in the air we breathe condense into a little cloud and after floating around a while gradually disappear and become reabsorbed in the atmosphere. Assume that at the moment of this reabsorption we should undergo an instantaneous transformation of all our proportions so that our new dimensions become infinitesimal in comparison with our former state. Do you think that we would recognize the fact that we had changed? The theory of relativity declares that we would not know what had happened, because with the alteration in proportions the ratios would remain constant. The change would express itself in the new dimensions of objects around us. The little globules of water composing the little cloud would now appear like stars and planets occupying immense areas in distant spaces, far apart from each other, and all undergoing a slow age-long evolution. Such a change would be signalized as a new time and a new space.

Yet the principle of relativity does not appear to our physical senses to represent a truth of nature. It is noteworthy that the principle of relativity is usually invoked when conditions are unstable, when thought is confused, and when a period of readjustment is in progress. Thus the Einstein theory may be representative of present-day harmonies, but yet may prove, in the future, to have been merely a passing philosophic mood.

Bagehot, a shrewd observer, writing in 1868 about the changes wrought by Darwin's evolutionary theory, said: "There is scarcely a department of science or art which is the same, or at all the same, as it was fifty years ago. A new world of inventions has grown up around us which we cannot help seeing; a new world of ideas is in the air, and affects us though we do not see it." Those were very true words more than half a century ago, yet they serve to describe present conditions!

GENERAL INDEX

A, vowel sound, record of, iv, 234

Aard-vark, xii, 281-2

Abacus, or calculating machines, xv, 183-4, xvi, 61

Abalones, xii, 71
Abbe, Prof. Cleveland, i, 216-17
Abbot, Dr., solar studies, ii, 171, 186-7
Abdomen, blood circulation in, ix, 196, 197;
methods of examination, x, 147, 371;
muscles of, ix, 77

Abdominal Organs, control of circulation of, ix, 215, 216, 217, 220;
development of, in black and white races, xv, 50;
mesentery support of, ix, 59;
smooth muscles in, 160-1
Aberration of Light, ii, 91-2
Abert, Lake, Oregon, xiv, 203
Abnormal Complexes, x, 355-6
Absaroka Range, xiv, 104-5, 226

Abscesses, cause (germs) of, x, 195, 198, 221;
cure of neurasthenic, 58-9
Absinthe, source, xiii, 266
Absolute, technical meaning, iv, 381
Absolute Magnitude (stars), ii, 317;
Adams' method of determining, 124, 153;
spectral type and, 115, 317;
used in measuring star distances, 318, 330

Absolute Maximum & Minimum (meteorology), i, 204, 365

Absolute Scale (thermometry), i, 73, iv, 141, viii, 107-8

Absolute Units, iv, 64, 69, 70

Absolute Zero, i, 73, iv, 141, v, 347-8, viii, 107-8;
molecular condition at, iv, 142-3, viii, 108;
nearest approach, i, 32, iv, 173, xvi, 194;
of outer space, vi, 270

Absorption Lines, ii, 111-12 (see Fraunhofer Lines, Spectrum)

Abstract Ideas, difficulty of attention to, xi, 228, 233-4;
expression of, in primitive language, xv, 144-150

Abul Wefa, Arab astronomer, ii, 38

Acceleration, definition & measurement, iv, 57, 381;
force in relation to 59-61, 63-4, 71-2;
of gravity, 65
Accidents, from electricity, x, 254;
from fatigue, xi, 274;
prevention of, vii, 32-3, xi, 365
Accidents (geological), xiv, 188
Accommodation, of vision, ix, 110-11, 113;
muscles of, 161, 162
Accumulators, storage batteries, iv, 300
Accumulators, water-pressure, v, 106
Accuracy, habit and, xi, 253;
indifferent types of men, 156, 157, 158-9
Acetic Acid, vi, 111, viii, 220;
solubility, 112;
in vinegar, 218, 249, 293
Acetylene Gas, discovery, xvi, 190;
formation, vii, 312;
in steel making, 321;
luminosity of flame, viii, 60;
preparation & uses, 231
Achenes, xiii, 58-9, 344, 345

Acheson, Dr. Edward G., vii, 300-1, 309-10, xvi, 189-90

Acheulean Implements, xv, 105, 107
Achromatic Lenses, iv, 373;
invention, xvi, 125-6
Achromatic Refractors, ii, 100-1, 103
Acidosis, x, 280
Acids, viii, 19-20, 114-15, 373;
action on saccharides, 226, 228;
amino, 230 (see Amino Acids);
bases and, 115;
defined by ionization theory, 122;
electrolytes, 125;
formation, 20, 39, 118, 373;
formation in body, x, 280-1;
hydrogen prepared from, viii, 32-3, 102;
ionization in solution, 119-25, 300-1;
manufacture of, 275-6;
molecular structure, 218;
molecular structure & physical state, 298;
nomenclature, viii, 98;
organic, 52, 219-21;
oxygen in, 34;
salts formed from, 72, 83, 114, 373;
vegetable, 222-3, 336, 349;
volumetric analysis of, 292-3
Acid Salts, viii, 116
Acne, causes of, x, 201, 311
Aconite, xiii, 252
Acorns, xiii, 193;
dispersal by squirrels, 55-6, 340;
survival rate, xv, 21
Acoustic Clouds, i, 190
Acoustics, atmospheric, i, 186-96;
of auditoriums, iv, 239
(see also Sound)

Acquaintanceships, selection of, xi, 257, 380-1

Acquired Characters, inheritance of, ix, 325-7, x, 230

Acquired Tastes, xi, 72-3
Actinic Rays, iv, 365-6, 381, vii, 250, 361
Actinolite, iii, 321-2
Action & Reaction, iv, 33-4, v, 143;
Newton's law, ii, 66, iv, 69

Activity, food needs dependent on, ix, 295, 296, 297;
mind as, xi, 12, 13, 236;
temperature effects on, i, 323-4
Activity (mechanics), iv, 80
Adaptations, of eardrum to sound, xi, 100;
of eye to colors, 95;
of nose to odors, 80-1;
of skin to pressures, 111;
of tongue to tastes, 72;
to warmth and cold, 113
Adaptation to Environment, xv, 16;
by animals, 16-18;
by man, 3, 25, 26, 28, 31, 36;
by plants, xiii, 11, 12, 28-31, 89-90, 149-50, 346, 355-83, xv, 16, 18-19;
between insects & plants, xiii, 144, xvi, 152-3;
mental efforts at, x, 361-2;
natural selection and, xv, 24-5;
principle never perfect, xvi, 152-3

(see also Environment, Environmental Variation)

Adder's Tongue Fern, xiii, 159
Adding Machines, v, 326-7
Addison, Thomas, x, 106, 112
Adenoids, ix, 104, 224, x, 341-2;
as infection foci, 220
Adenoid Tissue, ix, 223, 224
Ader, C., v, 231
Adiabatic Changes, iv, 158-9, 381
Adipose Tissues, ix, 298
Adirondack Mountains, age, iii, 191;
club mosses in, xiii, 305;
erratic bowlders in, iii, 70;
fault blocks in, 89;
fault lines and streams, xiv, 128;
granite formation, iii, 112;
Grenville strata, 165, 167;
ice age survivals, xiii, 321;
iron district, iii, 359;
lakes, how formed, 145;
lightning effects, 24;
Ordovician strata eroded, iii, 186;
quartz & slate formations, xvi, 29
Adjutant Bird, xii, 255
Admiration, sentiment of, xi, 146-7
Adolescence, mental conditions of, x, 236-7

Adrenalin, ix, 171-2, 209, 219, xi, 137, 138, 273

Adrenals, ix, 170-1;
Addison's disease of, x, 112-13;
functions, xi, 60, 137;
shock effects, 59
Adriatic Sea, bora, i, 133;
coasts of, xiv, 252-3, 263;
filling in by deltas, 53;
Karst district, 150
Adsorption, viii, 316, 373
Adulteration of Food, viii, 370-1
Adults, basal metabolism in, x, 271;
growth in, ix, 287, 288-9;
heart rate in, x, 334;
protein needs of, ix, 281-3
Advance Metal, resistance, vi, 77
Advertising, psychology of, xi, 343-9;
sign & display, vii, 339-43;
tied images in, xi, 221;
weather considerations, i, 255-6
Ægean Sea, volcanoes, xiv, 317, 319
Æolian Tones i, 195
Aerial Echoes, i, 190, 193
Aerial Roots, xiii, 20-2;
of fig tree, (illus.), 48
Aerials, iv, 314, vii, 261;
Dolbear's patent, xvi, 191;
in aeroplane sets, vii, 282
(see also Antennæ)
Aeroclinoscope, i, 282, 365
Aerology, i, 18-19, 20-3, 89, 365-6
Aeronautical Meteorology, i, 284-305

Aeronautics, accidents & safety questions, i, 49-50;
accidents in World War, x, 246;
aneroid barometer importance in, iv, 124;
fog in, i, 94, 95, 300-2;
history & future, 39-51;
Langley's work in, iv, 43-4;
pilot balloons in, i, 22;
therapeutic possibilities, 51;
weather importance, 284-6;
wind & air currents, 126, 130, 289-300
(see also Aeroplanes, Balloons)
Aeroplanes, altitudes attained, i, 22, 46;
altitude effects, 303;
astronomical use, ii, 208, 212, 225-6, 382;
Brocken specters seen from, i, 185;
engine efficiency, v, 170;
gyroscopic stabilizing, 343-4;
helicopter, i, 42;
history & development, 40-1, iv, 43-4, v, 230-3, 382, 383-4;
landings, i, 42, 45, 294 (fig.) 302;
mail service, 44-5, vii, 76;
meteorological uses, i, 22;
passenger, 41-2, 43-5, 50;
photographic mapping by, 45-8;
principles, i, 286-305, v, 233-8;
propellers (tractors) of, iv, 34;
radiotelephony and, vii, 282-3;
rise or "taking off" of, iv, 43;
safety question, i, 49-50;
stereograms from, xi, 180-1;
uses, present & future, i, 41-2, 43-9;
war uses, v, 107, 372-3, 375;
wind effects, i, 285-6, 289-300;
wireless directing, vii, 283;
World War, i, 185, 308, 312, vii, 283, x, 246
(see also Aeronautics, Aviators)
Æsculapius, x, 16, 17;
temples of, 17, xvi, 44
Æsthetic Arts, development of, xv, 297-324
Æsthetic Instinct, xvi, 47, 48
Æther of Space, vi, 118-20;
constitution, vii, 368;
elastic solid theory, xvi, 137;
universal presence of, iv, 180-1

Æther Waves, various kinds, vi, 119, 269, vii, 249, 250, 259-61, 371

Aetius, medieval writer, x, 31
Ætna (see Etna)
Affection, emotion of, xi, 147;
importance, 129;
seat of, ix, 200

Africa, animals of (carnivora), xii, 339, 342, 344, 345, 348, 352-3, 355, 356-7, 359, 360, 365;
animals,(herbivora) xii, 302, 303, 304-5, 308, 310, 320-1, 327-8, 329;
anteaters of, 281;
antiquity of man in, xvi, 64;
bats of, xii, 370;
birds of, 249, 260, 266, 267;
"bush" lands of, xiv, 378-9, 380;
coasts & islands, 251-2, 263;
coasts contrasted, xii, 40, xiv, 305;
coffee production in, xiii, 233;
crocodiles, xii, 199-200;
drainage system, xiv, 190;
dust haze, west coast, i, 55;
elephant-trapping in, xv, 225;
exploration of, xiv, 196-7;
forests of, 366, 368-9, 382;
fishes of, xii, 151, 154, 160, 166;
former submergences, iii, 216, 235;
geographical features & results, xv, 136;
Gold Coast, death rate on, 50;
grasslands in south, xiv, 384;
health conditions, 197, 223-4;
lemurs of, xii, 374, 375;
lizards, 208;
monkeys & apes, 379, 380, 383;
palm oil, importance to, xiii, 11;
plains of, xiv, 217-18;
plateau of interior, 196, 221, 222;
rivers, broken courses, 155;
rivers, navigability of, 196;
rock weathering in central, 78;
rodents of, xii, 288, 289-90;
rubber production, xiii, 248;
salt lakes, viii, 139;
short races of, xv, 38-9;
sleeping sickness in, x, 167-70;
smallpox superstition of natives, 285-6;
snakes of, xii, 214, 226, 227-8, 231-2;
timber supplies, xiv, 382;
vegetables originating in, xiii, 222-7;
volcanoes & lava fields, xiv, 317;
yellow fever on coasts, x, 160
(see also East, North, South, West Africa)

African Savages, body decoration of, xv, 256, 257-8;
debtors, treatment of, 370;
language changes, 155;
rule of fathers among, 367
(see also Bushmen)

African Sleeping Sickness, x, 167-70, 199, xiv, 197, 223, 357;
chemotherapy in, x, 381;
Koch's work on, 150, 169
After-Images, xi, 90-2, 220;
of sun (green flash), i, 171
After-Summers, i, 362, 366
Agassiz, Lake, iii, 144, xiv, 201;
plain of, 215-16

Agassiz, Louis, discoverer of Ice Age, iii, 236;
on fish scales, xii, 134;
on snapping turtles, 188
Agate, iii, 337
Age, chronological & physical, ix, 214;
effect on disease, x, 236-7;
growth in relation to, ix, 288-9
Agonic Lines, iv, 246, 247
Agoutis, xii, 289
Agramonte, Dr. Aristide, x, 160, 200
Agricultural Chemistry, viii, 334-47

(see also Fertilizers, Nitrogen, Potash, Soils)

Agricultural Implements & Machinery, v, 239-50, xv, 235-6;

Egyptian, xvi, 72;
electricity in, vii, 230
Agricultural Meteorology, i, 245-60
Agricultural Stage, xv, 187, 199-203;
polygamy in, 288;
rulers in, 367
Agriculture, ancient centers of, xiii, 221;
beginnings of, 209-10, xv, 200-2;
civilization and, 128;
fundamental importance, xiv, 218;
grasslands and, 383;
plains most favorable to, 218-19;
possibilities, by what determined, 64;
summer rain importance, 352
Ailerons, i, 289, 299, v, 238, 343
Air, amount consumed by breathing, ix, 256;
ancient ideas, xvi, 79;
as balloon ballast, v, 226;
boiling point of, iv, 173;
buoyant power of, 107, 108;
burning of, in gas, viii, 55, 56;
burning, in gasoline engines, v, 156-7;
"change of" (vertical), i, 51;
closeness or stuffiness of, (see Ventilation);
combustion and, i, 10;
composition, 9-16, vii, 321, viii, 66-8, ix, 254, 268;
composition, discovery of, xvi, 120, 121;
compressed (see Compressed Air);
compressibility, v, 126;
cooling power, i, 318, 319-21;
critical temperature & pressure, iv, 172, 173;
decay in relation to, xiii, 312-13;
density of, iv, 113, 198;
drying power, i, 77, 323;
dryness & dampness, viii, 67, xiv, 353-4;
elasticity of, iv, 198, v, 126;
electrical conductivity, i, 144-5, iv, 259, 265;
expansion by heat, 151;
frozen, v, 345;
health benefits of special types of, x, 241;
heat conductivity, iv, 178, 179;
ionization, i, 142-4, 146, 150;
life without, (see Anaërobic);
liquefaction of, iv, 171, 172;
(see Liquid Air);
moisture capacity, xiv, 352-4
(see also Humidity);
molecular velocity in, iv, 133;
necessity to life, ii, 244, 245;
necessity to plants, xiii, 102, 109;
physics of, historical development, iv, 28-30;
popular & scientific conceptions, i, 9-10;
pressure of, iv, 132
(see also Atmospheric Pressure);
purifying by ozone, i, 15, vii, 354;
purity tests, i, 321-2;
resistance due to inertia, v, 234;
resistance effects on aeroplanes, i, 286-9, iv, 43, v, 235-6;
resistance to falling bodies, iv, 42, 97;
resistance to projectiles, v, 369;
saturated, i, 14, viii, 67;
shimmering of, i, 174, iv, 328, 329;
in soil, xiii, 92;
solubility in water, viii, 111;
sound transmission by, i, 186, iv, 195, 198-9, 201, ix, 98-9;
specific heat of, iv, 161;
specific heat ratio, 156;
surfeit of, bodily effects, 31;
ventilation of, (see Ventilation);
vibrations of, 215;
warming of, by sunshine, 182;
warming of, by freezing water, 161;
weight of, 107, 116, 124, v, 221-2, 230;
weight, discovery of, iv, 29, 114-16;
weight of heated, v, 223
(see also Atmosphere)
Air Bladder, xii, 135-6, 164-5
Air Brakes, iv, 129, 200, v, 130-3, 380, 381;
on electric cars, vii, 185-6
Air Columns, resonance of, iv, 226-31;
vibrations of, 215

Air Compressors, i, 26-7, iv, 128, v, 89-93, 127-8

Air-cooled Engines, v, 160-1
Air Currents in aeronautics, i, 293-300;
pilot balloons to discover, 21-2
Air Cushioning, v, 133-5
Air Holes, i, 298-9, 374, v, 224
Air Jets, v, 135-6
Airlifts, iv, 130, v, 114-15
Air Locks, v, 118-19, 124
Air Pumps, iv, 126-7
Airships, in forest service, i, 49;
future landing places, 43;
future uses in transportation, 42-3;
high altitude effects, 303;
history of development, 40-1;
possibilities of, iv, 107-8
(see also Dirigible Balloons, Zeppelins)
Air Springs, v, 126-38
Air Waves, i, 294 (fig.), 298
Akeley, Carl E., v, 136
Alabama, aluminum production, iii, 369;
chalk deposits, 216;
coal beds, 199;
iron production, 358-9;
soil of, xiv, 218
Alabaster, iii, 331, 332, viii, 149
Alaska, animals of, xii, 318, 319, 320, 337;
auks of, 265;
blackfish of, 163;
coal fields, iii, 348;
coast changes, earthquake of 1899, 97, xiv, 34, 114, 334-5;
coast formations, iii, 57;
fiord coasts, xiv, 258, 259;
glaciers, iii, 59, 60, 62, xiv, 55, 60;
gold production, iii, 366, 367;
ice age in, 239
Albania, story of unchangeableness, v, 251
Albategnius, ii, 38
Albatross, xii, 251-2
Albe, E. Fournier d', v, 332
Albucasius of El-Zahra, x, 32
Albumens (see Proteins)
Albuminuria, x, 345-6
Alcmæon, Greek anatomist, xvi, 82-3
Alcohol, (ethyl or grain), viii, 212, 213-14;
boiling point, iv, 168;
cooling by, 174;
conversion to acetic acid, viii, 218;
denatured, 250;
flame of, 60;
formula of, 218;
freezing point of water lowered by, 299-300;
frozen, v, 345;
frozen in liquid air, i, 31;
future motor fuel, viii, 209;
manufacture, 250;
per cent in distilled beverages, 250;
physiological effects, ix, 94, 214, 244, 248-9, 320-1;
production by fermentation, viii, 213-14, 248-50, ix, 248, x, 138;
solvent properties, viii, 217;
specific gravity of, iv, 112;
(see also Alcohols)
Alcoholic Drinks, viii, 249-50;
arterial elasticity impaired by, ix, 214;
food value, viii, 366, ix, 248-9;
in tropics, xv, 126-7;
stomach absorption increased by, ix, 244;
warmth produced by, 94, 320-1
Alcoholic Fermentation, viii, 248-9;
in body, ix, 248-9;
Pasteur's studies, x, 138
Alcoholometer, iv, 113
Alcohols, viii, 212-14, 373;
boiling points, 299;
double & triple, 215;
in esters, 221;
molecular complexity & physical state, 298;
in plants, 349;
relation to ethers, aldehydes & acids, 216-18, 219;
solubility, 37, 112
Aldebaran, angular diameter, ii, 151;
Arabic name, 39;
chemical composition, 114-15;
color, 297;
gaseous state, 382
Aldehydes, viii, 218, 219, 373;
in sugars, 225
Alder Flies, xii, 106
Alder Trees, xiii, 193, 271-2
Aleutian Islands, blue foxes of, xii, 344;
former connections, xiii, 351;
volcanic nature, iii, 106, 139, xiv, 315, 316
Alexander of Tralles, x, 31, 59
Alexanderson Generators, vii, 274-5, 290-1
Alexines, of blood, x, 210-11
Alfalfa, fertilization, xiii, 138-9;
in pea family, 198;
nitrogen fixation by, xiv, 66
Alfonsine Tables, ii, 39, 44
Alfred the Great, language of, xv, 156;
navy of, xiv, 261
Algæ, xiii, 72-3;
classification work, xvi, 166;
curious "showers" of, i, 358-9;
fossils of, xiii, 303, 304 (illus.);
found in hot springs, ii, 249, xiii, 299;
in sea, xii, 16-7, xvi, 147;
number of species, xiii, 323;
oldest of plants, 303-4;
reign of, 314, 323
Algeria, animals of, xii, 326, 359;
dust storms, i, 54;
record temperature, 209;
snowfalls, 210
Algol, actual magnitude, ii, 321-2;
secondary minimum, 328;
type of variables, 325-6
Algonquin Lake, iii, 149-50
Alimentary Canal, ix, 233 (fig.);
foci of infection in, x, 220;
in infants, ix, 346;
operation of muscles, xi, 37-8, 69;
protection against germs, x, 202;
sterile at birth, 201;
X-ray examinations of, 373
Alimentary Disorders, x, 319-38
Aliphatic, defined, viii, 373
Alkali Industries, viii, 276-8
Alkali Metals, viii, 132-47
Alkalis, defined, viii, 373;
deposits, 139;
volumetric analysis, 292
Alkaloids, viii, 240
Allbutt, Clifford, xvi, 184;
Osler and, x, 151;
quoted, 35
Allegheny Plateau, xiv, 221;
coal of, iii, 346-7;
origin of present relief, 231-2
Allelomorphs, xvi, 157
Allergy, x, 216-7
Alligators, xii, 182, 196-8;
savage methods of luring, xv, 222
Allotropic Forms, viii, 43, 87, 373
Alloys, viii, 272-3;
aluminum, iii, 369-70;
antimony in, viii, 169;
copper, 164;
electrolytic refinement, vii, 319-21;
melting point of, iv, 161-2
Alluvial Cones, iii, 33
Alluvial Soils, xiv, 63, 70-1
Almanacs, ancient Greek & Roman, i, 67-8;
Arabic word, ii, 39;
weather predictions in, 243-4
(see also Nautical Almanacs)
Alpenglow, i, 168, 366

Alphabet, invention & development of, xv, 175-6, xvi, 60

Alpha Centauri, magnitude, motion and type, ii, 319;
parallax and distance, 312, 313, 314-15
Alpha Lyræ, drift of sun toward, ii, 18, 306;
parallax, 312
Alpha Rays, i, 143, viii, 185
Alpine Glaciers, iii, 60, 62-3
Alpine Racial Group, xvi, 49-50
Alps Mountains, Alpenglow, i, 168;
Arctic species in, xiv, 365-6, 377;
chamois of, xii, 325;
foehn wall, i, 105;
forming of present, iii, 236, xiv, 233;

Glacial Epoch, lakes from, iii, 146, xiv, 200;
glaciers and snow line, iii, 59, 60, 62, 240, xiv, 55;
goats of, xii, 326;
hanging valleys and electric plants, xiv, 57;
historical and economic importance, 240-2, 243, 244, 245, xv, 137-8;
intense folding of, xiv, 36, 230;
lakes, iii, 143-46;
marine deposits, 235;
massif of, xiv, 234;
Napoleon's passage of, 244;
passes of, 58, 240-1;
population and industries, 241-2;
railways and tunnels, 240-1;
rainfall effects, 355;
rivers of, 167;
rock destruction by frost, 76;
snowfall measurement, i, 118;
solar heat at Davos, 210;
thickness of strata in, xiv, 229;
winds, i, 131-2, 133;
youthfulness of, xiv, 96

Alsace, potash deposits, viii, 279, xiv, 67-8, 209

Altamira, Spain, cave pictures, iii, 305, xv, 114, 116, 118, 298

Alternating Currents, iv, 307, vi, 153, 154-5, vii, 361;
ammeters for, vii, 166, 169-72;
carbon arcs on, 208-9;
circuit breakers for, 37-8, 40-1;
condensers' effects, vi, 304-5;
conversion to direct, 330-48;
cycles, 153, 154-5;
inductance, 166-7, 169 (see Inductance);
lag and lead phases, vi, 167-9, 171-4, vii, 362;
lighting and magnetic effects, vi, 155-7;
measurement of power, 165-9, 172;
Ohm's Law for, 164-5, 170;
sonic waves and, v, 108;
transmission of power by, vi, 159-60, 195-6;
uses, common and special, 152;
use in electric furnaces, vii, 305-6;
use in electrotherapy, 236-7, 244, 248-9;
use in traction, vi, 161-3, vii, 186, 196;
use in wireless, iv, 315, vi, 163;
voltage changed, 159-60 (see Transformers);
voltmeters for, vii, 154-5, 161-5;
wattmeters for, 172, 173, 177
Alternating Current Generators, iv, 307
(see also Alternators)
Alternating Current Motors, vi, 240-63

Alternation of Generations, xiii, 160, xvi, 166

Alternators, construction, types, and uses, vi, 157-9, 196-216;
operation in power plants, 357, 374;
ratings, 192-4;
synchronizing action, 383-4;
voltages attained, 159;
wireless, vii, 290-1
Altimeter, i, 72, 366
Altitude, barometric measurement of, iv, 124;
barometric pressure and, i, 23, 72, 171, 303;
climatic effects, xiv, 220, 223, 364-6;
potential variations with, i, 144-5;
pressure table, iv, 124;
rock weathering in relation to, xiv, 40;
sound and, i, 186-8;
temperature and, 19, 20, 303
Alto-Cumulus Clouds, i, 100, 101, 103, 298
Alto-Stratus Clouds, i, 100-3
Alum, Alums, viii, 312-13;
in water filtering, 320

Aluminum, Aluminium, affinity strength, viii, 128;
atomic weight and symbol, 383;
chemical activity, 149, 155;
compounds, unstable, 137, 257;
density of, iv, 113;
electrical conductivity, 283;
electrolytic reduction, vii, 320, viii, 271, 284;
gold plating of, vii, 319;
in heavy metal group, viii, 126-7;
melting point and heat, iv, 162, viii, 384;
occurrence, 19, 129, 148, 154, 198;
percentage in earth's crust, iii, 308, viii, 192;
production and uses, iii, 369-70, viii, 154-5;
salts astringent, 116;
sound velocity in, iv, 201;
specific gravity, viii, 384;
test for, 287, 288-9
Aluminum Arresters, vii, 17, 50
Aluminum Wire, vi, 80, vii, 23
Amalgam, defined, viii, 373
Amalgamation, defined, vi, 132;
in electric cells, 132, 139;
in gold and silver extraction, viii, 131, 270
Amaryllis Family, xiii, 188
Amatus Lusitanus, x, 58
Amazon River, arapaima fish of, xii, 154;
arrau turtle of, 193-4;
Black caiman of, 198;
electric eel of, 160;
forests and swamps, xiii, 360;
jaguars of, xii, 362;
length and volume, xiv, 189;
poison of natives on, xv, 228;
tributaries, connections, xiv, 187;
water boas of, xii, 216;
water lily of, xiii, 359-60
Amazon Stone, iii, 328
Amber, in varnishes, viii, 265;
insect remains found in, iii, 16, 280;
magnetism of, iv, 256, vi, 11, 12
Ambergris, xii, 299
Ambrose Channel, dredging of, v, 257-8;
sediment in, xiv, 269;
wireless pilot system, vii, 284-5
America, antiquity of man in, xiv, 149;
compass needle directions in, iv, 246;
discovery and settlement of, xiv, 309-11;
discovery of, effect on botany, x, 45;
first hospital in, 81;
plants restricted to, xiii, 320;
vegetables and fruits originating in, 222-7 (see North and South America)

American Buildings, dryness and heat in, i, 322-3, xiv, 353

American Colonies, Appalachian barrier, xiv, 191, 194, 242, 243, 249;
first hospital, x, 81;
independence results, 107;
medicine in, 81, 104;
ordeals practiced in, xv, 373;
westward growth by rivers, xiv, 193-4
American Indians (see Indians)

American System (Manufactures), v, 48-56, 213-14

Amethyst, iii, 337;
oriental, 327
Amides, viii, 373;
acid, 230
Amines, viii, 210, 214, 215, 373
Amino, defined, viii, 374
Amino Acids, chemistry of, viii, 230, 309-10;
physiological origin and use, ix, 279-84, 287-8, x, 204, 277, 278, 279;
proteins compose of, viii, 230, 351, 352
Amino Compounds, viii, 236-7
Amino Derivatives, viii, 210, 214, 215
Ammeters, iv, 279-80, vii, 165-72, 361;
automobile, 121;
galvanometers as, 179;
hot-wire, 163-4
Ammonia, viii, 68-70;
amines from, 215;
atmospheric, i, 11, 13, ix, 269;
boiling and freezing points, iv, 173;
critical temperature and pressure, 173;
density of, 113;
discovery, xvi, 120;
Gay-Lussac's studies, 133;
in explosives, viii, 74, 75, 253;
in fertilizers, 147, 253;
in ice-making, v, 357, 358, 380, viii, 69, 70;
in nitrogen cycle, 73;
in sweat, ix, 276;
metal test, viii, 288-9;
name, 98;
production, natural and artificial, i, 13, 35, 36, 153, viii, 46, 47, 68, 74, 75, 252, 253, 276, 278, xvi, 165;
production and disposition in body, ix, 284-5, x, 279-80;
refrigeration by, iv, 174, 187-8, viii, 69-70;
solubility, 111
Ammonia Water, viii, 68, 147
Ammonites, iii, 275, xii, 75
Ammonium, viii, 93, 147;
test for, 287, 289
Ammonium Compounds, viii, 147;
carbonate, 137;
hydroxide, 70, 121, 147, 288;
nitrite, 121;
salts, 147, 280;
sulphide, 289
Amorphous, defined, viii, 374
Ampère, A. M., vi, 20-1;
current unit named for, iv, 278;
rule of magnetic deflection, 275

Ampere, electric current unit, iv, 278, 284, vi, 69, 70, vii, 361

(see also Electric Currents, Ohm's Law)
Ampere-turns, iv, 288, vii, 362
Amphibians, iii, 285, xii, 167-81;
age of, iii, 20;
first appearance of, xv, 71;
in oceanic islands, xiv, 278;
relations to fishes and reptiles, iii, 284, 286, xii, 165, 183

Amphibole, iii, 321-3
Amphitheatres, mountain, iii, 66
Amphoteric, meaning, viii, 352
Amundsen, Capt., aeroplanes of, i, 46
Amyl Acetate, viii, 221
Amyl Alcohol, viii, 210, 214, 249
Amylases, viii, 357, x, 326
Amyloid, viii, 255
Anacondas, (boas), xii, 216
Anadromous Fishes, xii, 155

Anaërobic Bacteria, in peat production, xiii, 313;
in sewage treatment, viii, 328
Analytical Chemistry, viii, 285-95
Analyzers, crystal, iv, 354
Anamnesis, x, 370
Anaphylaxis, x, 212-15, 223
Anatomy, Chinese systems of, x, 13;
development of science of, 24, 30, 41-2, 44-5, 49, 51-2, 81, 116, 117, xvi, 82-3, 179-80

Anaxagoras, on origin of earth, ii, 366-7;
theory of matter, xvi, 83, 118

Anaximander, theory of universe, ii, 367, xvi, 77-8

Anaximenes, theory of universe, ii, 366-7, xvi, 79

Andes Lightning, i, 149
Andes Mountains, glaciers of, xiv, 54;
impassability, 250;
lightning, i, 149;
mineral wealth, xiv, 237;
rivers, 167;
snow pinnacles, i, 116-17;
upraised in Cretaceous Period, iii, 219;
volcanoes, xiv, 315;
youthfulness of, 96, 235
Andrews, Thomas, i, 29, xvi, 175

Andromeda, nebula in, ii, 135-6, 136-7, 357, 361;
new stars in nebula, 332-3
Anel, Dominique, x, 90-1
Anemia, x, 337;
blood transfusion in, 338;
cause and effects, xi, 370-1;
of adolescence, x, 237;
pernicious, discovery of, 112
Anemograms, i, 295, 366
Anemometers, i, 83-4, 366;
for gusts, 295

Aneroid Barometer, i, 71, 72, 366, iv, 123-4, 381

Anesthetics, discovery and use in surgery, x, 123-5, 148, xvi, 180, 185;
effect on impulses, xi, 20;
Hindu use of, x, 13;
medieval, 41
Aneurisms, x, 28 note;
formation and rupture of, 336;
treatment of, 28, 91-2
Angel Fish, xii, 164
Anger, xi, 139, 141;
basic causes of, ix, 153, 166;
expression of, by monkeys, xv, 64;
in various sentiments, xi, 146, 148, 149, 150;
pain and, 120;
physical accompaniments of, ix, 240-1;
self-forgetfulness in, xi, 134
Angiosperms, xiii, 175-9;
alternation of generations in, xvi, 166;
first appearance and spread, iii, 256-7, xiii, 317-18

Anglers, (fish) eyes of, xii, 138;
"lure" of, 133
Angleworms, xii, 51-3;
power of distinguishing light, ix, 105
Anglo-Saxon Language, xv, 156-7
Anglo-Saxons, in Nordic group, xvi, 48;
use of tea, xiii, 229
Angular Diameters of Stars, ii, 150-1;
measurement of, 322-3
Anhydride, defined, viii, 374
Aniline, viii, 52, 237
Aniline Dyes, xvi, 163;
fluorescence of, iv, 379
Animalculæ, (see Unicellular Animals)
Animal Electricity, vi, 16, 17, 19, 23, 64
(see also Electric Fishes)
Animal Fats, viii, 246 (see Fats)

Animal Kingdom, classification, iii, 259-60, xii, 25-9;
how distinguished, viii, 349, xii, 14, 15, xiii, 13, 14;
relations to vegetable, viii, 334
Animal Protein, ix, 279, 280
(see also Proteins)
Animals, xii, 270;
activities of, ix, 20-1;
adaptation to environment, v, 16-18, 24, xvi, 152;
admiration unfelt by, xi, 146;
æsthetic emotions, xvi, 145-6;
anaphylaxis in, x, 212, 213, 214;
appendix uses in, xv, 56;
appetite in, ix, 88;
arctic, in mountains, xiv, 376-7;
artificial heat use by, ix, 308, xv, 229-30;
body heat regulation in, ix, 307, 308, 311;
brain in, xv, 62-3;
cannibalism in, ix, 280-1;
care of skin and coverings by, x, 310;
care of young, xv, 275-6;
carnivorous, xii, 332-65;
cell structure, 25;
chemistry of body and nutrition, viii, 348-70;
chromosomes in different species, ix, 46;
classification, xii, 25-9;
climatic influences, xvi, 141;
climatic limitations, xiv, 363-64;
cold-blooded (see Cold-blooded Animals);
communication means, xv, 140-1;
courtship of, 274-5;
differences of protoplasm in, ix, 278-9;
direction perception by, 117;
differences of complexity in, 48-50;
diseases of, x, 206;
distribution facilitated by land arrangement, xiv, 21;
domestication of, xv, 197-8;
ear movements in, ix, 82, 117;
educability of, xv, 66;
embryological development, 54-5;
evolution, Anaximander on, xvi, 78-9;
experience, profiting by, ix, 139, 152, xv, 66;
expressions of emotions by, 63-5;
face and brain case in, 43;
fear in various, xi, 136;
fear and anger effects, ix, 166;
flesh of, as food, 24, 284-6, xv, 333-4;
foods of, viii, 349, 350, ix, 24, 29, 30;
food procuring by, 18-20, 73-4;
geological history, iii, 12, 259, 306;
grasping ability of, ix, 67, 68, 82;
growth of, on what dependent, 287-9;
hair erection in, 161, 166;
heredity in, x, 231-2;
hoofed, xii, 300-31;
hunger and thirst senses in, ix, 87;
hunting and trapping of, xv, 222-7, 227-8;
hypertrophy of heart in, x, 331-2;
imagination in, xi, 224;
imitation in, xv, 66;
impulses instinctive, 273;
instincts of, 65-6;
land (see Land Animals);
later than plants, xiii, 298;
Latin names, xii, 28-9;
leadership among, xv, 361;
light and darkness effects on, x, 253;
locomotion, v, 215, ix, 73-4;
luminous, i, 346-7;
man's lessons from, xv, 206, 208, 220;
man's relation to, 53, 68;
marine (see Marine Animals);
"moral standards" applied to, xii, 351;
mutation in, ix, 342;
nitrogen uses, viii, 73;
of continental islands, xiv, 271;
of oceanic islands, 277-8;
oldest known remains, iii, 238, (Pl. 13);
physiology of, remarks on, ix, 305;
plants and interrelations, viii, 334, 335, 347, 349, 350, xiii, 82;
power development in, ix, 15, 16, 17, 18;
protective devices, xv, 16-18;
qualities, studies of, xvi, 143;
rate of increase, xv, 19-21;
reason in, xi, 243-4, xv, 67-8;
reflex actions in, 65;
regulatory mechanism in, x, 249-50;
reproduction from cells, 228, xvi, 155-6;
salts in body fluids, ix, 175-6;
seasonal phenomena, i, 254, 256;
seed dispersal by, xiii, 55, 58, 340, 343;
sense of sight in, ix, 105;
sense of smell in, 96-7, xi, 82;
sex relations among, xv, 274, 276-7;
smelling motions in, ix, 82-3;
struggle for existence among, xv, 21-2;
tool-using by, v, 9-11, x, 67-8;
touch sense in, 91;
unicellular, (see Unicellular Animals);
useful, xii, 324-31;
variation in, xv, 22-3 (see Variation);
vitamine needs and stores, x, 256-60;
warm and cold blooded, ix, 305;
water scarcity effects, 37-8;
wild, xii, 332-65;
young, metabolism in, ix, 38-9
Animal Starch, viii, 350
Animal Worship, xv, 333-4, 340-1
Animists, Animist Theory, x, 84-5
Anion, defined, iv, 381
Annuals (plants), xiv, 367;
garden species, xiii, 289, 297;
life of, 53, 152;
roots of, 15, 16
Anoa, of Celebes, xii, 330
Anode, defined, iv, 317, 381, vii, 251, 362;
first defined by Faraday, vi, 23
Antarctica, blizzards of, i, 133;
coal deposits, 199;
extent and elevation, xiv, 20, 22, 26;
former connection with S. America, 290;
glaciers of, 55;
island or continent, 23;
plateau, 222;
penguins of, xii, 251;
rainlessness, i, 109;
uninhabitability, xiv, 21;
winds of, i, 128-9
Antarctic Ice Sheet, iii, 62, 237
Antarctic Ocean, current of, xiv, 299, 305;
extent of, 22-3;
sea elephant of, xii, 335;
whales of, 298
Antares, angular diameter, ii, 151, 322-3;
color, 297;
former name, 302;
gaseous state, 382;
type III star, 115
Anteaters, xii, 281-3;
banded, 274;
scales of, xv, 220-1;
spiny, xii, 272-3
Antecedent Rivers, xiv, 164-70, 174
Antelopes, xii, 326-8;
fear in, xi, 136;
hunting of, with cheetah, xii, 365;
pronghorn, 322-3
Antennæ, of insects, xii, 100-1
Antennæ (wireless), iv, 314, vii, 261;
construction, 264-5;
effective resistance, 298;
fundamental wave-lengths, 266, 294;
of receiving stations, 267;
types, 295-6
Antenna Circuit, vii, 263-7;
energy dissipation, 297-8;
inductance and capacitance, 294-5, 296-7;
radiation, on what dependent, 298
Anthelion, i, 366;
oblique arcs of, 378
Antheridia, xiii, 158, 159, 161
Anthers, of flowers, xiii, 45, 118, 119
Anthracene, viii, 240, 253
Anthracite Coal, iii, 344;
beds in U. S., 347-8;
constituents, 345, viii, 44;
graphitic, iii, 345;
lessening supply, 346;
loss of heat with, v, 155
(see also Hard Coal)
Anthrax, Koch's studies of, x, 149;
Pasteur's work on, 140-2
Anthropoid Apes, xii, 381-4;
primates, 373;
susceptibility to human diseases, x, 206

Anthropology, Volume xv, defined, xv, 10, 11, 15, xvi, 36, 47;
daily interest, 26, 29
Antibodies, x, 205, 216
Anticathode, defined, iv, 381
Antichlor, viii, 140
Anticline, defined, iii, 377;
illustrated, 85, 128 (Plate 7), xiv, 95
Anticrepuscular Rays, i, 169, 366
Anticyclones, i, 134-5, 366, xiv, 349, 350;
Siberian, i, 218
Antigens, x, 205, 217
Antimony, affinity strength, viii, 128;
atomic weight and symbol, 383;
expansion on solidifying, iv, 150;
fusibility, viii, 384;
ores, 198, 270;
specific gravity, 384;
tests, 287-8;
uses in industry, 169;
use of, in medicine, x, 12, 50, 169
Antinodal Current, vii, 297
Antinori, Luigi, i, 213
Antiseptics, viii, 332-3;
Carrel-Dakin solutions, x, 181-3, 382;
discovery, 40, 145-6, xvi, 180, 182-3
Antiseptic Surgery, x, 146-7;
history of development of, 40, 55, 145-6, 381-2, xvi, 108, 114, 182-4;
in World War, x, 181-3, 381-2
Antitoxins, x, 218, 296-8;
of diphtheria, 197, 212, 213-14, 218, 296-8;
of tetanus, 218, 299
Antitrade Winds, i, 366, xiv, 348
Anti-twilight Arch, i, 167, 366
Antlers, xii, 316, 317, 319
Ant Lions, xii, 106
Antony, Mark, speech on Cæsar, xi, 331
Ants, aphids of, xii, 101;
appearance in Triassic, 104;
nest repairing by larvæ, v, 10;
numbers in tropics, xii, 282;
"showers" of, i, 357;
social habits, xii, 124, 125, 126;
underground rooms of, xv, 266
Antwerp bombardment, audibility, i, 191;
harbor of, xiv, 270
Antyllus, x, 28
Anuria, x, 344-5
Aorta, ix, 196, 201 (fig.), x, 334;
elasticity of, ix, 210;
ligation of, x, 129-30
Aoudad, xii, 326
Apatite, iii, 323, viii, 193
Apes, anthropoid, xii, 381-4;
black of Celebes, 379;
brain of, xv, 62, 90-1;
embryological development, 54-5;
imitation in, 66;
manlike, iii, 301-3, xv, 88-95;
man's relation to, xv, 56-7;
nostrils of, xii, 376, xv, 46;
physical comparison of, with man, iii, 301, (fig.), xv, 57-62;
reasoning power, 67-8;
sex relations among, 277-8;
skull capacity, xv, 89;
skull shape, 42-3;
tigers and, xii, 362;
tool-using by, v, 9;
working methods, xv, 58
Aphids, xii, 118;
ants and, 101
Aphis Lions, xii, 106
Aphrodite (sea mouse), xii, 54
Apian, Peter, ii, 41;
comet of, 85
Aplysia, xii, 68
Apollonius of Perga, ii, 31, xvi, 90
Appalachia, iii, 195, 205, 210

Appalachian Mountains, antiquity of, xiv, 96, 235;

Catskill formation, iii, 195;
coal beds, iii, 346-7, 204, xiv, 237;
folding intensity, iii, 86, xiv, 36, 230;
forests, xiv, 372;
former elk of, xii, 317;
geological history, iii, 130, 132-4, 135-6, 140, 191, 205-7, 210, 219, xiv, 97-8, 168-9, 228-9, 235-6;

"grain" of, xiv, 99;
historical rôle, 191, 194, 242-3, 249;
igneous formations absent, 228, 230, 234;
iron deposits, iii, 358-9;
length and breadth, xiv, 36-7, 227;
limestone soils, iii, 27;
marble production, 371;
metallic ores of, xiv, 237;
non-marine deposits in trough, iii, 209-10, 214;
petroleum fields, 350;
plateau west of, xiv, 221;
present relief, origin, iii, 231-2;
ridges and valleys, 36, 137, 233-4, xiv, 94, 97-8, 234, 236;
rivers across, iii, 36, 137, 233, xiv, 166-7, 168-9, 180-2;
site formerly submerged, iii, 12, 130, 168, 181, 184, 187, 194-5, 197, 198;
springs, thermal and mineral, 128, xiv, 143;
strata, thickness and composition, iii, 132, 180, xiv, 228-9;
strata of various periods, iii, 184, 187, 195-6, 203;
stream capture in, xiv, 180-2;
thrust faults, iii, 90;
typical range, xiv, 226;
wind and water gaps, iii, 39, xiv, 58, 98, 169

Appalachian Revolution, iii, 205, 208, 210
Appalachian System, xiv, 227
Appalachian Valley, xiv, 167
Appendicitis, asepsis in, x, 147;
cause of, 224
Appendix, ix, 233 (fig.);
as infection center, x, 220;
in man and animals, xv, 56
Appetite, ix, 87-8, 299;
exercise effects, x, 303-4
Apples, acids of, viii, 223;
development of, xiii, 54;
food value, viii, 365, ix, 250-1, 299, x, 268
Apple Tree, family, xiii, 197-8;
origin, 224;
petal arrangement, 190
Apteryx, xii, 249
Aquamarine, iii, 325
Aqua Regia, viii, 174

Aquatic Animals, mental inertness of, xii, 140,

(see also Crustaceans, Mollusks, Naids, Polyps)

Aquatic Plants, first on earth, xiii, 300, 301, 303;
fertilization, 123, 149-52;
fossils, 303;
in lakes, xiv, 210

Arabia, animals of, xii, 249, 327, 342, 344, 359;

Danish scientific expedition, xvi, 123;
plains of, xiv, 217;
source of coffee, xiii, 231, 283
Arabian Horses, xii, 307
Arabian Language, xv, 162;
words from, in English, 161
Arabic Numerals, xv, 184, xvi, 62, 103

Arabs astronomy of, ii, 11, 36-9, 302, xvi, 100;
bananas known to, xiii, 216;
mathematical advances, ii, 12, xvi, 54, 103;
medical science of, x, 31-3, 36, 37-8, 39, 40, 100;
sciences of, xvi, 54, 100;
sugar introduced by, xiii, 215

Arago, discovery of magnetism of rotation, vi, 21;
lightning studies, i, 146
Aral, Sea of, depression of, xiv, 203;
shallowness and salinity, 206-7;
size of, 204
Arapaima Fish, xii, 154
Arara Cockatoo, v, 9-10
Arcadian Range, xiv, 227
Arcathagus, x, 25
Arc Furnaces, vii, 303
Arc Generators, vii, 291
Archæopteryx, xii, 239-41
Archegonia, xiii, 158, 159, 161
Archeozoic Era, iii, 164-75;
life in, 262, 263, 265, xv, 71
Archeozoic Rocks, iii, 164-74;
graphite found in, 249-50;
iron ores in, 358
Arches, false and true, xv, 268-9;
weak in earthquakes, xiv, 342
Archimedes, iv, 25, 26;
mathematical and other work, xvi, 89, 90;
principle of, iv, 30, 102-5, 107;
screw of, 26-7 (fig.)

Arc Lamp, Arc Light, iv, 310-11, 352, vi, 279, 280-3;

Bunsen's carbon rods, xvi, 189;
compared with sun, ii, 169;
Davy's experiment with, vi, 19;
direct and alternating currents on, vi, 332, vii, 208-9;
graphite electrodes, vii, 300, 308
Arc Process, i, 36, vii, 323-4
Arcs of Lowitz, i, 366
Arctic Archipelago, xiv, 20
Arctic Current, xiv, 304-5
Arctic Ocean, copepods of, xii, 84;
depths, xiv, 22;
enclosed character, 22, 290, 299

Arctic Plants, in mountains, xiii, 321, xiv, 365-6, 376-7

Arctic Regions, conditions of life in, xv, 123-4;
forests of Coal Age, xiii, 307;
frozen soil of, xiv, 75;
growing season in, 375;
plant conditions in, 365;
seals of, xii, 335;
skin canoes of, xv, 264;
snow line in, 72-3;
wolves of, xii, 340-1;
winds, i, 127, 128
(see also Polar Regions)
Arcturus, angular diameter, ii, 151;
decreasing distance, 120;
displacement lines in spectrum, 119;
gaseous state, 382;
origin of name, 302;
parallax, 316;
"solar" star, 115
Arequipa Observatory, ii, 145-6
Arethusa (plant), xiii, 186 (fig.)
Argentina, ancient sloths of, xii, 283;
hail rods, i, 343;
pampas of, (see Pampas);
stock-raising, xiv, 384;
weather service, i, 228-9 (note), ii, 186-7;
wheat cultivation, xiii, 211

Argon, discovery and character, i, 10, 11, 12, viii, 67, 181, 309;
electric lamp filler, i, 33;
periodic classification, viii, 182-3;
symbol and atomic weight, 383
Argonauts, (shellfish), xii, 77-8
Argonne Forest, xiv, 91
Arid Regions, alkali deposits, viii, 139;
dust whirls, i, 60;
mineral matter in waters, viii, 196;
plants of, xv, 18-9;
rainfall of, i, 109, 112;
rock weathering in, xiv, 41-2, 51-2, 77-9, 124;
soils of, 68-9, 383
(see also Deserts)
Aristarchus of Samos, ii, 10, 27-8
Aristillus, ii, 28-9, 31
Aristocracy, changing ideas of, xv, 377
Aristocratic Type, xiii, 356
Aristotle, association principles, xi, 197-8;
authority in Middle Ages, ii, 33, 42;
conception of cosmos, ii, 367;
lectures on fossils, etc., xvi, 168;
medical work of, x, 23, 27, 74;
meteorological treatise, i, 67;
monad theory, xvi, 118;
on falling bodies, ii, 53;
on knowledge and perceptions, xvi, 87;
on Mars, ii, 227;
on origin of earth, xvi, 78;
on shooting stars, ii, 283;
scientific methods, xvi, 88-9;
syllogism invention, 88;
zoölogical work, 126
Arizona, arid topography, xiv, 42;
cactus plants, xiii, 28, 106-7;
chapparal of, xiv, 379;
cliff lines of, 88;
climate of plateau, 222;
copper mines, iii, 360;
faults at Bisbee, 90;
forests of, xiv, 220-1, 373-4;
Gila monster of, xii, 204, 207;
mesas, xiv, 82;
sunniest state, i, 86;
timber limits, xiv, 373;
volcanic fields of, 102, 315, 317, 318
Arkansas, aluminum production, iii, 369;
hot springs of, xiv, 143, 144;
malaria campaign in, x, 173-4
Arkwright, Richard, v, 274, 376
Armadillos, xii, 282, 283-4;
scales of, xv, 220
Armature Reaction, vi, 190, vii, 145-6

Armatures of Dynamos, iv, 307, vi, 176, vii, 362;
of direct current generators, vi, 178, 179-86;
of alternators, 196, 197-8, 202, 205, 207, 210, 212-13

Armatures of Magnets, iv, 250, vi, 30 (fig.), vii, 362;
uses of, iv, 291-2
Armatures of Motors, vi, 223, 224-5, 235-6
Armies, crowd psychology in, xi, 326-7;
fatigue in retreat, 275
Armor, development of, xv, 220-1
Armored Cable Wiring, vii, 61-2, 362
Armor Fishes, iii, 281, 282, 284
Armorican Range, xiv, 96, 235
Armor Plate, making of, v, 323, 382
Arms, arteries of, ix, 196-7;
bones of, 67-8, (fig.), 77, (fig.);
bones, growth of, 58;
equal length of, 169-70;
freedom of movement of, 66;
grasping organs, 82;
length as yard measure, iv, 45;
length in man and apes, xv, 57, 59;
muscles of, ix, 76-7
Arnold of Villanova, x, 41
Aromatic Hydrocarbons, viii, 232-6, 374
Arrack, from coco palm, xv, 125;
Indian, xiii, 213

Arrhenius, on Martian life, ii, 248 on osmotic pressure, xvi, 164;
theory of life, xii, 9
Arrows, development, and use of, xv, 213-16;
Indian, 196 (fig.)
Arsenic, affinity strength, viii, 128;
atomic weight and symbol, 383;
in copper ore, vii, 320;
ores of, viii, 198, 270;
properties, 169;
specific gravity, 384;
tests for, 201, 287, 288
Art, primitive types of, xv, 110-21;
science and, iv, 9
Arterial Blood, ix, 260, 263, 264
Arterial Pressure, ix, 213-14, x, 334
Arteries, ix, 191, 196-7, x, 334;
bleeding from, discovery of, 39;
caliber changes in small, ix, 215;
connection with veins, 192-3 (fig.), 197;
elasticity of, 59, 210-12, 213-14;
former ideas of, x, 62, 63, 65, xvi, 106;
hardening of, x, 334-6;
ligating of, 56, 96;
"man as old as," ix, 214, x, 335;
passage of blood along, ix, 211-12;
systole and diastole of, x, 62, 63-4, 65
Artesian Wells, iii, 118-19, xiv, 138;
constancy of, 152;
of North Dakota, 12, 139;
warm water from, 144

Arthropods, iii, 260, 263, 264, 276-80, xii, 81, 126

Arthur's Seat, Scotland, xiv, 112

Artichokes, xiii, 206, 222

Artificial Ice, production, v, 349-50, 354-8, viii, 69, 70

Artificial Light, colors in, ix, 115;
gains from, iv, 51
Artificial Limbs, x, 190
Artillery, armor versus, v, 368;
distance audible, i, 188-9
(see also Guns, Projectiles)
Artillery Plant, xiii, 56

Arts, æsthetic, origin and development, xv, 296-325

Arts of Life, xv, 205-72
Arum, fertilization of wild, xiii, 153
Arum Family, xiii, 188;
flower arrangement, 52
Aryan Languages, xv, 161, 162, 163
Aryans, in Nordic group, xvi, 48;
of India, 53;
rule of fathers among, xv, 367
Asbestos, iii, 338
Ascension Island, xiv, 289
Ascidians, xii, 19, 20, 129
Asclepiades, x, 25-6
Asepsis, in surgery, x, 14, 134, 146-8;
Lister on, 144-5
Ash, viii, 374;
handling in power plants, vi, 356;
of coal, viii, 44, 45;
of plants, xiv, 65-6;
volcanic, 324
Ash Trees, for gardens, xiii, 271-2;
leaves, 36-7;
seed dispersal, 58, 343

Asia, animals of, xii, (herbivora), 302, 305, 313, 314, 317, 320, 327;
animals (carnivorous), 336, 339, 344, 345, 352, 356, 357, 365;
birds of, 263;
climate changes, results, iii, 75, xiv, 361-2, xvi, 141;
climate of eastern, xiv, 345;
crocodiles of, xii, 201;
drainage system, xiv, 190, 195-6;
earthquake belts, 331-2;
eastern coast, 248-64;
faulted topography of eastern, 124-5;
food plant regions, xiii, 221;
forests, xiv, 369-77;
formerly united with America, xii, 313, xiii, 351, xiv, 30;
geological history, iii, 216, 235-6;
grasslands and deserts, xiv, 381;
monsoon countries, conditions in, 359-60;
plains, 217;
plants common with America, xiii, 351;
plateaus and mountains, xiv, 217-22;
rodents of, xii, 287-9;
rubber production, xiii, 248;
salt lakes, viii, 139;
snails of, xii, 69;
snakes of, 218, 226, 229, 231, 232;
terrestrial leeches, 55-6;
trees of eastern, xiv, 377;
vegetables and fruits originating in, xiii, 222-7;
volcanic fields, xiv, 316-18;
wind types, i, 131, 134, 136
Asia, Central (see Central Asia)
Asia Minor, climate changes in, xiv, 361-2;
plateau of, 222
Asiatic Volcanic Belt, xiv, 316
Asparagus, effects on urine, ix, 274-5;
green food, 27;
origin, xiii, 222;
stem of, 30
Asps, xii, 230
Assam Earthquake, iii, 98, xiv, 334
Asses, xii, 308
Association of Ideas, ix, 150-1, xi, 197-207;
in language, ix, 151-2;
memory and, 149-50;
in imagination, xi, 219-20, 209, 212, 216-17;
necessary to attention, 232-3, 234;
normal and abnormal complexes, x, 355
Assyria, civilization conditions, xv, 127;
art of, 301;
cuneiform writing, 175 (fig.);
history and civilization, xvi, 51-3;
skin rafts of, xv, 264;
sun-worship and astrology, ii, 20-1
Assyrian Language, xv, 162
Asteroids, discovery, ii, 254-7;
in solar system, 163-4;
life on, 248;
origin, 258, 371, 373, 374;
photographic study, 131-2;
size, shapes, and orbits, 162, 257-8
Asthma, bronchial, ix, 162, x, 223;
from adenoids, 342
Astigmatism, ix, 113-14, xi, 85
Astonishment, and fear, xi, 131
Astraphobia, i, 330-66
Astrolabes, ii, 11, 29, 34, 46-7, 93
Astrology, astronomy and, ii, 9, 20;
history in various countries, ii, 20-1, 23, 37, xvi, 58;
medical progress and, x, 14
Astronomical Instruments, Bessel on, ii, 93;
development of, 10, 11, 12-13, 13-14, 16, 161
Astronomical Photography, ii, 125-38;
in corona studies, 221-2, 225;
in parallax work, 314;
in nebular studies, 358;
telescopes used in, iv, 372-3
Astronomy, daily interest of, xvi, 12;
defined, 37;
exact science, x, 368;
history of, ii, 9-92, iv, 19, xvi, 56-8, 61, 69, 70, 81-2, 90-1, 100, 101, 102, 103, 124-5;
mathematical and descriptive, ii, 15, 16;
meteorology and, i, 7;
new and old, ii, 113-14;
personal measurements in, xi, 155-6;
spherical, ii, 29
Astronomy Today, Volume ii
Athletes, "form" in, ix, 159

Athletic Contests, value to spectators, xi, 139-40

Atlantic Cables, laying of first, vi, 24;

Telegraph Plateau and, xiv, 288

Atlantic Coast, shoal-water belt, xiv, 25, 285

Atlantic Coastal Plain, xiv, 213-14;
artesian wells in, iii, 119;
forests, xiii, 371, xiv, 372-3;
geological history, iii, 212-13, 216, 221, 231;
soils and agriculture of, xiv, 218-19

Atlantic Drainage System, xiv, 189-90

Atlantic Ocean, airship flights across, iv, 107, v, 228-30, 233;
birds of, xii, 251, 252, 253;
climates on opposite coasts, xiv, 345, 346-7;
clipper's time across, v, 188;
conformation of floor, xiv, 288-90;
coral reefs in, 264;
depths, iii, 51;
extent of, xiv, 22;
first steamship, v, 192-3, 378;
herring fisheries, xii, 156;
oceanic islands of, xiv, 277;
salt in, viii, 139;
temperature of water, xiv, 14, 297;
trade winds, i, 127, 130;
tree corals of, xii, 43;
unchanged for ages, iii, 55;
weather charts, i, 276;
wireless weather reports, 280
(see also North Atlantic)
Atlantic Seaboard, rainfall, i, 112;
super-electric zone, vi, 384
Atlantic Type of Coasts, xiv, 247, 249-50
Atlantic Volcanic Belt, xiv, 316
Atmometers, i, 88-9, 366
Atmosphere, anatomy of, i, 9-23;
circulation (winds and storms), 123-40, xiv, 347-51;
composition (gases), 9-16, viii, 66-8, 152;
dense, effects of, iv, 31-2;
density decrease upward, i, 16, 17, 171, 173, 303, iv, 108, 124, ix, 267-8, xiv, 354;
density irregularities, optical effects, i, 171-2;
disease germs in, 325-6;
dust and smoke in, 52-65, 325, vii, 216-17, ix, 269;
effect on colors of stars, ii, 296;
effect on meteors, 283, 285, 290;
effect on sunlight and colors, i, 165-6, 167-71;
electrification, 144, 145, 146, 150, vii, 207, 212-13, 216-17;
heat absorption by, iv, 194;
heating of, by sun, i, 123;
heat retention by, ii, 244, 382, iv, 183-4;
height, i, 16-18, ii, 244, iv, 116;
highway, i, 39-51;
layers (see Stratosphere, Troposphere);
light of, 164;
magnifying of, by telescopes, ii, 98, 140, 141;
meteorology, science of, i, 7;
nitrogen fixation from (see Nitrogen Fixation);
oxygen in upper, ix, 267-8;
radioactive emanations in, i, 143;
resources in, 24-38;
theories of origin, iii, 160, 163;
topographical work of, xiv, 62-79;
weight, i, 23, ii, 279, v, 222-30
(see also Air)

Atmosphere (unit of pressure), iv, 121, 123, 381, viii, 107

Atmospheric Acoustics, i, 186-96

Atmospheric Electricity, i, 141-63, vii, 201-19, 362;
in climatology, i, 211;
physiological effects, 330
Atmospheric Engine, Newcomen's, v, 144
Atmospheric Optics, i, 164-85, iv, 327-9

Atmospheric Pressure, amount and direction, i, 23, ii, 244, iv, 116-23, v, 222, viii, 107;
amount at different elevations, iv, 124;
body regulation to, x, 250;
boiling point and, iv, 170, viii, 303;
discovery of, iv, 114-16, 132, v, 112;
early experiments with, iv, 29-30;
equalization in ear, ix, 102;
isobars, i, 125-26;
life in relation to, ii, 245-48, xi, 53;
measurement, i, 70-2, iv, 120, 121, 123, 124;
physiological effect of changes, i, 303, 327-9;
stratosphere in relation to, 20;
unit of, iv, 121, 123, 381, viii, 107;
variations with temperature, iv, 121-3, 124-5;
weather and, i, 70, 237-8, 241-2

(see also Pressure Areas);
winds in relation to, 124, 125-6, 127-9, 134-5;
work done by, 25, v, 112-15, 137-8

Atmospheric Refraction, i, 167-74, 380, iv, 327-30;
early studies of, ii, 32, 41
Atolls, xii, 41
Atomic Energy, ii, 384, v, 181, viii, 186-7
Atomic Numbers, viii, 183, 309

Atomic Theory, history and deductions, viii, 110;
in Greek philosophy, xvi, 83-4, 87, 118;
Leibnitz's, 117-18
Atomic Volume, determination, viii, 307
Atomic Weights, viii, 92, 383;
chemical calculations by, 96;
classification of elements by, viii, 177-83, 189, xvi, 163;
determination of, viii, 306-7;
hydrogen basis, 33;
introduction, xvi, 134;
physical state and, viii, 297-8;
properties dependent on, xvi, 134;
radioactivity and, viii, 184, 185-6, 188;
regular increase in similar elements, 132, 176, 179;
specific gravity and, 313;
specific heat and, 308-9;
table, vii, 384, viii, 383
Atomists, school of, xvi, 84-6
Atoms, viii, 25-7;
asymmetric, 309-10;
chromophor groups, 258;
defined, iv, 21, vi, 110-11, viii, 374;
vii, 362, disintegration, 185-7, 188;
dissociated, in ball lightning, vii, 214-15;
electrification, vi, 122-3;
energy of (see Atomic Energy);
Greek theory, xvi, 118;
laws involving, viii, 110;
Leibnitz on, xvi, 118;
magnetic fields of, vi, 117;
motion within, viii, 309-10;
of body, Epicurean theory, x, 26;
size, vi, 112-13, 115;
stability, vii, 215;
structure of, iv, 23, 55, vi, 113-15, 120-1, viii, 187-9, 307;
unchangeableness, 175-6
Attention, xi, 228-36;
habit and, 253-5;
methods of arousing, in advertising, 344-8;
ordinary meaning, 40

Attraction, scientific meaning, vii, 362, iv, 96

Audibility, distances and variations, i, 187-92;
vibration limits of, iv, 204, ix, 99

Audion, iv, 315-16, vi, 339 (fig.), vii, 279, xvi, 191-2

(see also Vacuum Tube)
Auditoriums, acoustic qualities, iv, 239;
cooling system, 188;
echoes in, 238

Auditory Nerve, ix, 101 (fig.), 142, xi, 30, 102;
internal and external stimulations, iv, 203
Auenbrugger, Leopold, x, 98-9, 110
Augite, iii, 336
Augustinus, Aurelius, xvi, 99-100
Auks, xii, 264-5
Aurelians, xii, 116
Aureoles, i, 184, 370
Aurignac Cave, iii, 305
Aurignacian Implements, xv, 100, 105, 108-9
Aurochs, xii, 331
Aurora, i, 158-62, 367;
altitude, 17;
magnetic disturbances with, vi, 40;
ozone from discharges, i, 16;
sun-spots and, ii, 176, 186
Ausable Chasm, iii, 44, 243, xiv, 128, 131
Auscultation, x, 108-10, 371

Australia, animals of, xii, 204, 249, 272, 274-5, 276-7, 278-80, 285;
barramundi fish of, 154;
barrier reef of, xii, 41, xiv, 263;
big trees, xiii, 26;
black swan of, xii, 259;
"bush" of, xiv, 378-9, 380;
bushmen, iii, 304;
climate, xiv, 358;
coasts, coral reefs on, xii, 40, 41;
desert sounds, i, 196;
former connections, xii, 277;
glacial and coal deposits, iii, 203-4;
grasslands, xiii, 373;
island or continent, xiv, 23;
ladybirds and scales, xv, 22;
landlocked area, xiv, 190, 222;
mining production, iii, 362, 365, 368, 370;
monsoons, i, 131;
mountains in Permian Period, iii, 205;
parrots of, xii, 266;
pearl fisheries of, 62;
plateau and plains, xiv, 218-22;
rabbit pest in, xv, 20;
ria coasts of, 257;
rivers and drainage of, xiv, 197;
sheep raising, 384;
snakes of, xii, 214-29;
temperate forests, xiii, 372;
timber supplies of, xiv, 382;
weather effects on history, i, 324;
wheat cultivation, xiii, 211;
wild rice, 214
Australians, xv, 193-5;
avenging of death by, 368;
beards, 38;
bird-catching by, 224;
boats of, 262;
body scarring by, 257-8;
boomerang of, 194, 208;
chieftains, 364;
color, 37;
cooking methods, 195, 233;
dances and music, 313-14;
digging sticks of, 235;
dogs used in hunting, 223;
dramatic ceremonies and plays, 306, 308-9;
duck hunting by, 222;
ideas of white men, 334;
message sticks, 166-7;
parrying stick of, 221;
sand drawings, 296;
songs of, 319-21;
spear-throwers of, 212 (fig.);
use of toes by, 61
Austria, beet sugar production, xiii, 216;
forests of, xiv, 238, 382;
Italy and, xiv, 244-5, 253;
Lake Dwellers of, xiii, 210;
loess deposits, xiv, 72;
Serbia and, 306
Autogenous Vaccines, x, 218

Auto-intoxication, ix, 249-52, x, 255, xi, 370;
in mothers, ix, 343-4
Automatic Heat Regulators, vii, 87-8
Automatic Regulation, vi, 101-2, vii, 362-3;
of motors, vi, 218, 224-9, 232
Automatic Telegraphy, vii, 112-13

Automatic Telephones, vi, 87, vii, 92-3, 106-7

Automobile Industry, v, 213-14, 383;
machine-tools and, 55-6, 214, 383
Automobiles, American, v, 213-14;
benzene fuels, viii, 235-6;
carburetors, vii, 124-8;
clutches, 143;
clutches, magnetic, vi, 104;
crank shafts, vii, 130-1;
cylinders, 130-1;
cylinder test, 128;
electric systems, 120-50;
engines, v, 156-61;
engine operation, vii, 123-33;
frost around exhaust, v, 128;
freezing of radiators, prevention, viii, 299;
future fuels, 209;
generator output regulation, vii, 144-50;
high and low speed air mixtures, 126-7;
history of development, v, 207, 212-13, 377, 383;
horns, iv, 240-1;
ignition system, vii, 130-41, 243;
ignition test, 128;
ignorance of drivers, 122-3;
lighting systems, 122, 135, 141-2;
limitations on use, i, 41-2;
lubrication, vii, 300;
magnesium parts, viii, 127-49;
magnetos, vii, 135, 139-41;
motion pictures of, iv, 349;
mufflers, v, 165;
Owen's magnetic, vi, 104;
power source, ix, 15, 74;
present attitude toward, vii, 299;
racing cars, v, 214;
roads and, 214-15;
springs air-cushioned, 134;
starters, vi, 99, 238-9, vii, 120, 127, 135, 142-3;
steel alloys used in, xiv, 238;
steering-gear, v, 38;
storage battery care, vii, 121, 127, 144;
tires, v, 133-4, 204;
tires burst by heat, iv, 151;
unit systems, vii, 135-6;
voltmeters, 163
Autonomic Nervous System, xi, 134-5, 137
Autophytes, xiii, 96-7
Autosuggestion, xi, 305-10;
in hypnotism, 311-20;
in salesmanship, 336-41;
in sleep, 287-8;
positive, 278
Autotransformers, vi, 327-8, 337 (fig.);
in wireless systems, vii, 266-91
Autumn, frosts, i, 258;
leaves in, xiii, 79, 175;
rate of advance (U. S.), i, 256
Aviators, altitude effects, i, 303;
complete rainbow seen by, 175;
fog effects, 300-1;
heights attained by, ix, 267-8;
sense of balance, v, 343;
sixth sense, i, 292;
training of, x, 242;
visibility obstacles, i, 303;
weather service for, 206, 227, 230, 231, 233, 286, 304-5

Avicenna, x, 32-3;
arterial bleeding unknown to, 39;
books burned by Paracelsus, 47;
translation of, 38;
views of fossils, iii, 14
Avitaminoses, x, 264
Avocations, importance of, xi, 375-6
Avogadro's Hypothesis, viii, 108-9, xvi, 133
Awe, sentiment of, xi, 147
Axolotl, xii, 173
Axons, of nerves, ix, 123-4, 125, 126, xi, 19
Aye-Ayes, xii, 374
Azaleas, xiii, 202, 203 (fig.), 289
Azores, xiv, 276, 289;
ocean depths near, 289;
rediscovery of, 309;
volcanic activity in, 316
Azores Plateau, xiv, 288

Aztecs, civilization, in temperate climate, xv, 123;
kings' oath, 366;
picture writing of, 169-78 (fig.);
tobacco use among, xiii, 257
Azurite, iii, 323
Baal, Phœnician sun-god, ii, 20
Babakotos, xii, 375
Baboons, xii, 379-81;
primates, 373
Babylon, wind-blown sand over, iii, 75;
world metropolis, xvi, 61
Babylonian Language, xv, 162

Babylonians, astronomy of, ii, 19-21, xvi, 56, 57-8, 61-2;
cuneiform writing, xv, 174, 175 (fig.), xvi, 60;
debt of Greeks and Egyptians to, 63, 66, 69, 70, 71;

Hammurabic code, 63;
history and civilization, 51-3, 55, 62-3;
idea of cosmos, 77;
magic of, 59;
mathematics, 61, 62, 103;
medicine of, x, 14, 15;
science, remarks on, xiv, 96
Babyroussa, xii, 310
Bacilli, x, 195;
of various diseases, 149, 165-6, 292, 295, 296, 298-9

Backstays of Sun, i, 169, 367
Bacon, calories in, ix, 299
Bacon, Francis, evolution known to, x, 136;
Harvey's small esteem for, 66;
influence on his times, 67;
on brontides, i, 196;
on knowledge, xi, 10;
scientific work, xvi, 113, 115, 125, 131
Bacon, Roger, xvi, 100-1
Bacteria, anærobic, xiii, 312-13;
atmospheric electricity and, i, 330;
breeding of, true, x, 195;
classification of, 195;
destruction by disinfectants, viii, 332-3;
destruction in blood, x, 209-11;
disease-making (see Disease Germs);
fermentation by, ix, 248;
flowerless plants, xiii, 13;
food of, ix, 27, 248;
in air, i, 61;
Chicago standards, viii, 332;
in body, x, 201-2, 204;
in intestines, ix, 247-9;
in sea, xii, 16;
Leeuwenhoek's studies, xvi, 107-8;
low temperature effects, i, 32;
luminous, 346, 349, xii, 20;
nitrogen fixation by, i, 35, viii, 340, 345, 346, x, 193-4, xiii, 98, xiv, 66;
number of species, xiii, 323;
origin of, xii, 12;
Pasteur's studies, xvi, 143;
preserving foods against, viii, 372;
sewage treatment by, 325, 327-9;
single-celled, xiii, 166;
size, i, 61, xiii, 63;
soil, xii, 15;
ultramicroscopic, x, 200;
useful forms of, 193-4
Bacteriemia, x, 220
Bacteriology, x, 194;
foundations of, 143, 196
Badgers, xii, 347-8
Bad Lands, iii, 139-40, 230, xiv, 62, 81-2
Bagehot, quoted, xvi, 198
Baglivi, x, 76, 77-8, 155
Bag-pipes, xv, 317
Baguio, Philippines, rainstorm at, 1, 110
Baguios, i, 136, 367
Bahamas, hurricane grass of, xiii, 344;
sisal production, 240;
wild fig tree, 18
Baikal, Lake, depth of, xiv, 204;
in rift valley, 123
Bailey's Beads, ii, 87
Baking Powders, viii, 136-7, 223
Baking Soda, viii, 135-6, 146, 278
Balance, sense of (see Equilibrium Sense)
Balanced Forces, v, 183-6
Balance Levers, v, 63-4 (fig.) 65
Balance Spring, invention, v, 65
Balance Wheels, v, 68-9, 71-2
Baldness, ancient treatment of, x, 12;
hats and, 309
Balearic Basin, xiv, 291
Balfour, Francis, x, 131
Ball-bearings, iv, 93, v, 206
Ballistic Wind, i, 313-67

Ball Lightning, i, 149-52, vii, 205-6, 213-15;
as ignis fatuus, i, 347
Ballon-sonde, i, 21, 367
Balloons, iv, 107-8, v, 219-30;
aerological uses and kinds, i, 18, 19, 20-2, 89, xvi, 177;
dirigible (see Dirigible Balloons), heights attained, i, 18, 22, 303, v, 225;
hydrogen in, iv, 108, viii, 33;
sounds heard, i, 188;
why they rise, 286, v, 221-2
Baltic Provinces, coasts of, xiv, 247
Baltic Racial Group, xvi, 48-9

Baltic Sea, development of trade of, xiv, 308;
formation of, 287;
green color, xvi, 147;
salt in, viii, 139, xiv, 296
Baltimore, harbor of, xiv, 268
Bamboo, in grass family, xiii, 179, 181;
rapid growth, 358;
stem, 26, 183;
tropical wood, xiv, 383
Banana, xiii, 216-18;
calories in, ix, 299;
flavor and odor, to what due, viii, 221;
food value, 365, x, 266-8;
in tropical forests, xiv, 368
Banana Oil, viii, 214, 221, 251
Bandai-san, eruption of, xiv, 324
Banks, oceanic, xiv, 286
Banyan Tree, xiii, 16 (illus.), 21
Bar, pressure unit, i, 70, 367
Barbados, overpopulation of, xiv, 282
Barbed Fruits, xiii, 58

Barbers, as surgeons, x, 35, 41, 54, 105, xvi, 181

Barberry Bush, xiii, 128-30
Barisal Guns, i, 195, 367
Barite, iii, 323;
gangue mineral, viii, 199
Barium, viii, 148;
affinity strength, 128;
atomic weight and symbol, 383;
flame color, 301;
fluorescence of, vii, 254;
specific gravity, viii, 384;
test for, 287-89
Barium Chloride, viii, 290, 301
Bark Lice, xii, 112
Barker, Dr., quoted, x, 375-6
Barley, composition and value, viii, 364;
malt from, 249;
ripening time, xiv, 365;
source, 382;
vitamines in, x, 262
Bar Magnets, iv, 242-3, 250, vi, 30-4
Barnacles, xii, 82, 84-5
Barns, electricity for, vii, 227-8;
lightning rods on, i, 156
Barocyclonometer, i, 280, 367
Barographs, i, 71-2, 367
Barometers, i, 70-2, 367, iv, 119-24;

Torricelli's development of, i, 68, iv, 29, 30, 114, xvi, 109, 177

Barometer Wells, i, 354, 367

Barometric Gradient, i, 126, 373

Barometric Pressure (see Atmospheric Pressure)

Barometric Tendency, i, 71-2, 367
Barotaxis, xi, 53, 61
Barramunda, xii, 154, 165-6
Barrel Gears, v, 27-8
Barrier Reefs, xii, 40-1, xiv, 263

Barton, Prof. W. M., author Medicine, Volume x

Bars, vibration rate of, iv, 223-4
Basal Metabolism (see Basic Metabolism)
Basaltic Lava, defined, iii, 377;
in Grand Canyon, 177;
jointing in, xiv, 129-30;
soils from, iii, 28

Basalt Rock, magnetized by lightning, i, 152-3

Base, Bases (chemistry), viii, 374;
defined by ionization theory, 122;
electrolytes, 125;
formation and character, 20, 39, 115, 117-18;
ionization in solution, 119-25, 300-1;
litmus effect, 114;
production, 276
Baseball, pitching of curves, iv, 67-9
Baseball Games, crowd psychology at, xi, 327;
value to spectators, 139-40
Baseball Players, sensory type, xi, 156

Base Level of Erosion, defined, iii, 30, 377, xiv, 40;
form of rivers at, 49;
of waves, 254
Base Plugs, vi, 276-7, vii, 72
Basic Metabolism, ix, 37, 78, x, 271;
daily amount in calories, ix, 296, x, 271;
disease effects on, ix, 302-4, x, 272;
heat production by, ix, 307;
of obese persons, x, 274;
protein stimulation of, ix, 301-2;
protoplasmic wastage by, 282-3;
temperature and water effects, 37-8
Basilar Membrane, of ear, iv, 203
Basin Ranges, formation of, xiv, 117
Basins, ocean, xiv, 286
Basket Fish, xii, 49
Baskets, Indian, xv, 248
Basques, isolation of, xv, 130
Bathrooms, lighting of, vii, 71-2
Baths, Bathing, ix, 313, 321-2, x, 311-12;
need of, after exercise, x, 304;
therapeutic uses, 311, 383;
warm for insomnia, xi, 289-90
(see also Cold Baths, Hot Baths)
Bats, xii, 369-72;
in oceanic islands, xiv, 277
Batteries, electric (see Electric Batteries)
Battles, crowd psychology in, xi, 326-7;
rain from, i, 336-8

Battleships, electrical applications (U. S. N.), vii, 325-35;
gun-training on, v, 104;
importance, vii, 325-6;
radio directing of, 284;
wireless telephony and, 281-3
Bauxite, iii, 369;
in basic refractories, vii, 307
Bayberry Bush, xiii, 191, 341
Bayliss, hormones discovery, x, 320;
secretin discovery, 325;
quoted, xi, 198-9
Bays, in irregular coasts, xiv, 252;
of ria coasts, 257
Beach, Alfred E., v, 138

Beach, Prof. Robin, author Electricity, Vols. vi, vii

Beaches, amphipods of, xii, 85;
features of, xiv, 246;
formation of, iii, 58, 81;
plants of, xiii, 381-2;
raised, iii, 81, xiv, 209;
rapid development of, iii, 58
Beach Fleas, xii, 81-5
Beach Walls, xiv, 246
Beachworms, xii, 54
Beaded Lightning, i, 149
"Beagle," voyage of, x, 134-5, xiv, 142
Beam Balance, iv, 101-2
Beam Warpers, v, 280

Beans, as food, viii, 365, ix, 34, 36, 299, x, 262-79;
food-obtaining devices, xiii, 97;
leaves, 36-7, 113;
movement of tendrils, 111;
in pea family, 198;
origin, 222;
petals, 47;
seeds, 56;
seed-leaves, 176
Beards, as race character, xv, 38
Bears, xii, 336-8;
canine teeth in, 333;
first cave-dwellers, xv, 206;
in Great Britain, xiv, 273
Beasts of Prey, xii, 332-65
Beats (sound), iv, 219-20, vii, 279
Beaufort Scale, i, 84, 367
Beaumont, William, ix, 240, x, 121, xvi, 186
Beauty, universal appreciation of, xvi, 145-6
Beaverdam Creek, iii, 38-9
Beaver-dam Lakes, iii, 157
Beavers, xii, 295-6;
first lumberers, xv, 206
Beckel Process, v, 287-8
Becquerel, Henri, xvi, 193
Bedbugs, xii, 114;
ancient, 104
Bedded Rock (see Sedimentary Rock)
Bedford Limestone, iii, 371-2
Bedrooms, air of, xi, 285;
furnishings and sleep, xi, 290;
lighting of, vi, 275-6, vii, 71
Beds, right, for sleep, xi, 290
Beebread, xiii, 124
Beech Forests, carbon used by, i, 14;
of Chile, xiv, 371;
of Denmark, xv, 86-7;
water requirements of, xiv, 377-8
Beech Trees, family, xiii, 193;
in landscaping, 271-2;
leaf-bud protection, 34;
of U. S., 368, xiv, 372
Beef, calories in, ix, 299;
proteins in, 279;
vitamines in, x, 262
Beef Extracts, value, viii, 362
Bees, xii, 125-6;
appearance in Tertiary, 104;
jaws and maxillæ in, 100;
plant visitors, xiii, 123-4, 126-7, 128-30, 137-9

Beeswax, viii, 221-45;
melting requirements, iv, 162
Beetles, xii, 121-4;
appearance of, 104
Beets, antiscurvy vitamines in, x, 266;
origin and antiquity, xiii, 222;
sugar storage in, ix, 27-8;
swelled roots, xiii, 19
(see also Sugar Beet)
Beet Sugar, viii, 226-7, 242, xiii, 216;
compared with glucose, ix, 230
Beginners' Luck, xi, 253
Begonias, coloring of leaves, xii, 42;
reproduction, 165-6
Beheaded Streams, xiv, 182-3
Behel, Jacob, v, 248
Belgians, in Alpine group, xvi, 49
Belgium, fossils found in, iii, 292;
German invasion, reasons, xiv, 91-2;
low elevation, 247;
mistpoeffers, i, 195;
tobacco consumption, xiii, 256;
topography of, xiv, 86 (map), 90-1;
zinc production, iii, 364

Bell, Alexander Graham, telephone invention, vii, 92, xvi, 188

Bell, Charles, x, 117
Bell, John, x, 129
Bell, Rev. Patrick, v, 246
Bell-crank Levers, v, 24-5
Belle Isle Strait, proposed damming, i, 345
Bells, vibrations of, iv, 221-2
Bell Telephone System, vii, 92;
automatic telephones, 106
Benedictine Order, medical work of, x, 36
Benguella Current, xiv, 305
Ben Nevis, rime growth, i, 122;
St. Elmo's Fire, 158
Benz, Karl, v, 213
Benzaldehyde, viii, 239
Benzene, viii, 51, 234-5, 374;
derivatives, 236;
from coal tar, 253;
freezing and melting points, iv, 163-4
Benzene Hydrocarbons, viii, 206, 232-6;
derivatives, 236-40;
products, 52, 241, 258
Benzene Ring, viii, 233, 234, 240
Benzine, viii, 234-5
Benzoic Acid, viii, 236, 239, 372
Benzol, viii, 234-5
Benzyl Alcohol, viii, 239
Benzyl Bromide, viii, 263
Berea Sandstone, iii, 372
Berengario of Carpi, x, 52, 60
Bergman, chemist, xvi, 119, 120, 174
Bergshrund, iii, 66
Bergson, philosophy of, xvi, 196
Beriberi, ix, 35-6, x, 257-9, 264;
cause of, viii, 369;
racial susceptibility to, xv, 50-1
Bering Sea, seal breeding in, xii, 334
Bering Strait, xiv, 22
Berkshire Hills, formation, iii, 188, 190
Berlin, sewage disposal, viii, 327
Berliner, Emile, gramophone, v, 328-9, 382;
transmitter, 381
Bermudas, climate of, xiv, 370-1;
coral reefs of, xii, 40
Bernard, Claude, x, 127-8, xvi, 185-6
Berries, xiii, 54;
poison in wayside, 252
Berson, balloon ascension, i, 18, v, 225
Bertrand, Alexandre, xvi, 185-6
Beryl, iii, 324-5
Berzelius, Jacob, xvi, 160-1, 165;
on fermentation, x, 138
Bessel, dismissal from Greenwich, xi, 156;
instruments and methods, ii, 16, 55;
on genius and instruments, 93;
prediction of, 124;
study of stellar parallaxes, 311-12, 313

Bessemer Converter, v, 319, 320, 322, 380, viii, 159;
invention, xvi, 175
Bessemer Steel, ore for, iii, 356
Besson, Dr. Louis, i, 181;
nephoscope, 86, 85 (fig.)
Beta Aurigæ, ii, 123
Beta Rays, i, 143, viii, 185
Betelgeuse, angular diameter, ii, 151, 322-3;
chemical study of, 114;
color, 297;
name, 39
Betel Nut, xiii, 254-5
Bevel Gears, v, 30-1;
primitive, 27-8

Beverages from various plants, xiii, 213, 219, 227-35

Bharal, xii, 326

Bianchini, ii, 99, 227

Bias, psychological effects, xi, 103, 208-9, 216

Biberthal, Switzerland, xiv, 186
Bible, account of man in, xv, 69;
Anglo-Saxon passage from, 157;
emotions depicted in, xi, 131;
"Great Sea" of, xiv, 358;
rice and sugar not mentioned, xiii, 214-15;
weather proverbs, i, 67
(see also New and Old Testaments)

Bicarbonate of Soda, medical uses of, x, 12, 322

Biceps, ix, 76-7 (fig.)
Bichat, x, 117
Bicycle Pump, i, 26-7
Bicycle Races, energy expenditure in, ix, 297
Bicycles, equilibrium maintenance on, iv, 62;
gyroscopic action, v, 343;
pedal invention, 380;
riding of, ix, 155-6, 158-9
Biela's Comet, ii, 280, 286
Biennials (plants), roots of, xiii, 16, 18
Bifocal Lenses, ix, 112;
invented by Franklin, x, 104
Big Creek Power Plant, v, 79, 81
Bigelow, Henry J., x, 125
Big Horn Sheep, xii, 326
Bigourdan, astronomer, ii, 358-9

Big Trees, Californian, age and size, xiii, 26;
branches, 86;
climatic changes seen in rings, i, 199, 200, xiv, 362;
former wide distribution, iii, 256, xiii, 352
(see also Sequoias)
Bihar, India, hailstorm, i, 120
Bile, ix, 237, 243, 275-6, x, 325-6, 329-30
Biliousness, x, 330
Billfish, xii, 152
Billings, John Shaw, xvi, 186
Billroth, Theodor, xvi, 183
Binary Stars, ii, 122-4, 334-5;
distance, 319-20;
orbit eccentricity, 377;
origin, 378-9;
periods, 319;
relation to Galaxy, 327;
variability, 326-7
(see also Double Stars)
Binding Machines, v, 247-8
Binoculars, principle of, xi, 180
Binomial Nomenclature, x, 84
Binturongs, xii, 353
Biochemistry, viii, 205, 348
Bioclimatic Law, i, 256, 367-8
Biology, defined, xvi, 36, 42;
history of development, 118, 142, 144-58;
medicine and, x, 369;
modern, due to Darwin, 134-6;
remarks on science of, 368
Biometry, science of, xvi, 153-8
Biot, balloon flights, i, 18;
meteor studies, ii, 284-5
Biotite, iii, 334

Birch Trees, antiquity of species, xiii, 324-5;
family, 193;
fertilization, 148;
in landscaping, 271-2;
seed dispersal, 343;
in U. S., 368, xiv, 372
Bird-catching, by Australians, xv, 224
Bird-catching Spiders, xii, 97
Birds, xii, 239-69;
anatomy of, 239, 247-8;
appearance in eocene, xv, 71;
care of young by, 275-6;
carinate, xii, 250;
colors of, 245-6;
courtships of, xv, 274-5;
embryological resemblances, 54;
evolution, iii, 286, 295-7, xii, 195, 239-43;
eyes of, xi, 98;
fear in, 136;
feathers of, xii, 243-7;
flower fertilization by, xiii, 123;
food of, ix, 24;
game, xii, 261-3;
heart of, x, 332;
infectious diseases of, 206;
luminous, i, 346-7;
man's lessons from, xv, 206;
migrations, cause, xiii, 55;
monogamy of, xv, 276-7;
oil-secreting organ of, x, 310;
orders of, xii, 249;
passerine, 268-9;
phosphorus in excrement, xiv, 68;
protective coloration in, xv, 17;
ratite, xii, 243-49;
ribs of, 184;
seed dispersal by, xiii, 55, 58, 59, 340-3;
sense of smell, xi, 78;
singing of, iv, 209;
singing organs, xii, 248-9;
sleeping habits, xi, 287;
teaching of young to fly, xv, 66, 275-6;
temperature regulation in, ix, 306, 307, 308;
used in hunting and fishing, xv, 223-4;
various groups, xii, 264-7;
warm-bloodedness of, ix, 305;
water, xii, 250-9
Birds of Paradise, courtships of, xv, 275;
plumes of, xii, 244
Birds of Prey, xii, 260-1
Birmingham Iron Region, iii, 358-9
Birs River, Jura Mountains, xiv, 94
Birth, ix, 344;
body conditions and development at, 345-52;
bones at, 58;
freedom from germs at, x, 201;
heart rate at, 334, ix, 347;
muscle cells at, 48, 348;
skull capacity at, xv, 40;
temperature changes at, xi, 36-7;
weight at, ix, 31
Births, male and female, ix, 340
Biscay, Bay of, depths, xiv, 289;
sand destruction in, iii, 75
Bishop's Ring, i, 58, 183, 368
Bismarck, skull capacity, xv, 40
Bismuth, affinity strength, viii, 128;
atomic weight and symbol, 383;
expansion on solidifying, iv, 150;
in Rose's fusible metal, 162;
melting point, viii, 384;
melting point, pressure effects on, iv, 163;
occurrence, viii, 131;
specific gravity, 384;
tests for, 287-8
Bisons, xii, 329-30;
formerly in Europe, xv, 76;
pictured in Cro-Magnon art, 114-18 (fig.)
Bitter, taste of, ix, 95, xi, 70, 71, 72
Bitterns, xii, 254-5

Bituminous Coal, beds in U.S., iii, 200-1, 346-7, 348;
elements, 345;
per cent carbon in, viii,
(see also Soft Coal)
Bituminous Strata, origin, iii, 249-50
Bivalves, xii, 58, 63

Black (color), absorption of light by, iv, 364, x, 309;
produced by interference of lights, iv, 377-8;
sensation of, ix, 115

Black, Joseph, chemical work, xvi, 119-20, 125, 177;
discovery of respiration physiology, x, 88-9
Black Beetles, xii, 107
Blackberry, aggregate fruit, xiii, 55;
in rose family, 197;
origin, 224;
running, 28
Blackbirds, xii, 269
Black Death, x, 163-4
"Black Earth," of Russia, xiv, 217
Blackfish, xii, 297
Black Forest, Germany, xiv, 238-9;
geology of, 87 (map), 90, 117, 128
Black Hills, xiv, 93, 227;
core of, 111;
former forests of, 373;
mineral springs of, 145

Black Hole of Calcutta, i, 321, ix, 268, x, 238

Black Lead, iii, 331, viii, 43 (see Graphite)
Black Lightning, i, 148
Black Powder, viii, 144-5, 260
Black Race, xv, 32;
brain and skull capacity, 41;
disease immunity and susceptibility, 48-9, 50-1;
facial angle in, 45;
fitted to tropics, 50;
jaw angle, 44;
nose index and nostril shape, 46;
peoples, 37;
separate origin theory, 69, 70;
skull shape, 42;
type characters of, 35

Black Sea, hanging valleys on shore of, xiv, 58;
importance of ports, 267;
salinity of, 296, viii, 139;
sturgeons of, xii, 152
Blacksnakes, xii, 218-19, 229
Blair, Henry, xvi, 187
Blanc, Mount, observatory on, ii, 142-9;
"resurrection," i, 168;
sound intensity on, 186
Blankets, warmth of, iv, 178
Blast Furnaces, v, 317-18;
air blast of, viii, 158;
ancient Egyptian, xvi, 74;
carbon uses, viii, 157;
cooling of air for, v, 347;
development of modern, 315-16, xvi, 174, 175, 176;
oxygen in, i, 33;
potash from dust, viii, 279
Blasting, v, 261-2;
explosives for, viii, 260;
with compressed air, i, 27;
with water, v, 100
Blasting Powders, viii, 137-8
Bleaching, chemistry of, viii, 86;
chlorine, 85-6;
hydrogen peroxide, 41, 86;
ozone, vii, 354;
sulphur dioxide, viii, 78, 146;
of wool, 256
Bleaching Powder, viii, 86-7, 146, 153, 274
Bleeders, Bleeding Sickness, ix, 181;
transmission of, x, 234
Bleeding, from arteries and veins, x, 39;
leeches used for, xii, 55;
stopping of, ix, 179-81
Blended Inheritance, ix, 334, x, 230-1;
in animal and plant breeding, ix, 337
Blériot, flight of, i, 43
Blight, cause of, xiii, 71

Blind, optophone reading for, v, 332, 334-5, 384;
space perception by, xi, 168-9
Blindness, black seen in, ix, 116;
cause, xi, 96-7;
from brain disease, ix, 146;
from cataract, 112
Blind Spot, xi, 87-9
Blish, Commander, v, 367-8
Blizzards, i, 133-4, 368;
device against, 345
Block and Tackle, v, 34-5
Block Mountains, iii, 138-9, xiv, 117, 226
Block Signal Systems, v, 211, vii, 355-9
Block Tin, viii, 161

Blood, absorption of digested food by, ix, 226, 243-6;
adrenalin effects, 171-2, xi, 137-8;
aeration of, by lungs, x, 62, 331;
amount in circulation, 337;
anemia, 337;
arterial, ix, 260, 263, 264;
carbon dioxide in, 190, 262-3;
effects, 264-7, x, 339;
carbon monoxide effects, viii, 50-1;
circulation of (see Circulation of the Blood);
clotting of, ix, 180, x, 88, 337;
coagulation after emotion, xi, 138-9;
coloring matter related to Chlorophyll, xii, 14;
color of, in relation to oxygen, ix, 259-61;
composition, 173-90;
control of vital processes by changes in, 168-72;
conveyer system, 191, 225;
corpuscle-forming tissues, growth of, 287;
distribution efficiency, x, 238-9;
emergency emotion effects, ix, 166, 171, 293, xi, 136-7;
fats in, ix, 289;
flow, how controlled, 215-16, 219-21;
functions, summarized, 50-1, x, 331-7;
germ destruction by white corpuscles, 197, 209-11;
in embryo, ix, 343;
interchange with tissue, fluids, 51 (fig.), 191, 193-5, 221-2;
iron and salts in, uses, viii, 354;
liver action on, x, 329;
maternal influences through, ix, 343-4;
mountain-sickness effects, i, 328;
neutrality or alkalinity of, x, 280-1;
oxygen supply and transportation, ix, 182-3, 198-9, 253-62, x, 338-9;
platelets of, ix, 188-9;
proteins of, 176-7, 194-5, 262-3;
rate of passage through heart, 210, 211, 212;
red corpuscles, 181-4 (see Red Corpuscles);
renewal of, 173;
sensations, effect on, xi, 68;
sleep effects, 283-5, 289;
soul in, Greek idea of, xv, 330;
sugar in, regulation and excess, ix, 290-3, x, 329, 330;
sugar increase in excitement, xi, 138;
temperature, v, 348-9;
temperature rise, effects, ix, 169, 315-16;
transfusion of, x, 337-8;
venous, ix, 263-4;
waste removal by and from, 271-6;
water absorption and supply, 247;
white corpuscles, 182 (fig.), 184-8
(see also White Corpuscles)
Blood-destroying Germ, x, 221
Blood Heat, i, 319
Blood Pressure, ix, 213-20, x, 334-6;
color effects, xi, 63, 96;
in sleep, 283-4
Blood Rains, i, 358
Blood Suckers, x, 91
Blood Vessels, ix, 191-3, 196-8;
classes and disorders of, x, 334-6;
climatic effects on efficiency, 238-9;
control of caliber of, ix, 161, 168, 215-16, 219-20, 311;
functions of, 50-1;
injuries, how mended, 180
Blooms, iron and steel, v, 317, 322
Blowers, electric, vii, 86
Blow Guns, xv, 216-17 (fig.)
Blowing Wells, i, 353-5, 368
Blowout, magnetic, vii, 37-9
Blue, complementary color of, iv, 367;
in birds' feathers, xii, 245;
in interior decoration, vi, 274;
of sky, i, 165, penetration of ocean by, xii, 22;
wave length of, iv, 365
Blueberries, xiii, 202, 224
"Blue Coal," v, 174
Blue Columbine, xiii, 126-8
Blue-grass Region, xiv, 68
Blue Grotto of Capri, iii, 81
Blue Gum Trees, xiii, 26, 94, 350;
leaves of, 106;
swamp draining by, xiv, 379
(see also Eucalyptus)

Blue Ridge Mountains, metamorphism in, xiv, 234

Bluffs, formation of, xiv, 84
Blunderbuss, v, 361
Boa Constrictor, xii, 215
Boas, family of, xii, 213, 215-16
Boats, evolution of, xv, 261-3;
propulsion of, 265
Bobcats, xii, 364-5
Bode's Law, ii, 254-5
Bodies, of matter, defined, iv, 12, 381
Body, anatomy and physiology of, ix;
care of against fatigue, xi, 279-80;
care of, instruction in, x, 282-5;
changes in, untransmitted, ix, 326;
chemical composition, viii, 348, 349, 353, 354-5;
construction features and units, ix, 12, 13;
dissection of, x, 30, 41-2, 45, 81;
efficiency of, viii, 367, ix, 306, x, 238-9;
electrical conductivity, iv, 259;
electricity effects, vii, 246-9, xi, 117;
emergency responses of, ix, 166-7, 171-2, 209, 220, 221, 293;
exercise effects, x, 303-4;
fatigue conditions, xi, 270-4;
fatigue results on resistance, x, 248;
food needs and utilization, (see Food);
functional disorders, x, 318-65;
functional regulation, 346-7, 352-3;
functions, chemical explanation of, xvi, 142;
functions, close connection of, xi, 31;
growth of (see Growth);
hair on, xv, 38;
hardening processes, x, 240;
infection portals, 198, 201-2;
kinetic system, xi, 57, 60-1;
living and nonliving parts, ix, 12, 13, 31;
machine parts suggested by, v, 20;
mechanisms of, 248;
metabolism (see Metabolism);
mind and, relations, xi, 13, 14, 61, 369-75;
motions, different kinds, ix, 82-3;
mutilations among savages, xv, 257-60;
painting of, 255-6;
poisonous effluvia of, ix, 269-70;
positions of, in relation to health, x, 241-2
(see also Postures);
pressures, xi, 53;
pressure of atmosphere on, i, 23;
proper clothing of, x, 306-10;
regulation to environment, 249-51;
reproduction from cells, ix, 324-5, 332-3;
resistance to disease germs, 177-9, 185-6, x, 203-12, 240, 248, 289, 292;
salt requirements, ix, 174;
seat of life in, 11, 12, 17;
shame of, xv, 254-5;
temperature, v, 348-9, ix, 306-7, 312, x, 250-1, 306;
temperature after hard work, ix, 317;
temperature equality, advantages of, 78-9;
temperature in different scales, iv, 137 (fig.);
temperature in fever, ix, 317-19;
temperature regulation, i, 316-17, 320-1, 322, v, 348-9, viii, 331, ix, 169, 305-23, x, 310;
temperature rise from excitement, xi, 140;
temperature rise in dense atmosphere, iv, 31;
tissues (see Tissues);
unstable chemical organization, xi, 134;
wastage and repair of, ix, 278-86;
waste elimination in tropics and cold climates, xv, 49, 50;
water functions in, viii, 355-6, wonders of, vi, 272;

X-ray effects, vii, 250
(see also particular parts and functions)
Body Cells, ix, 13, 41-3, xi, 15, 17, 49;
development of, ix, 43-8, 324-5, 332-3;
different kinds, 13, 39, 42-3, 277, 329;
living and nonliving, 12-17;
maintenance and growth, 34-6, 38-9, 189, 278-84, 287-9;
metabolism of (see Cell Metabolism);
oxygen needs and supply, 182, 199, 253, 254, 260;
power development in, 16, 17, 22, 36, 40;
salt needs, 174;
size of, 12;
sugar and fat supplies, 289-91;
supply and renewal system, 49-52, 193-5, 221-2, 262, 271;
supporting tissue, 71-2;
waste of, in starvation, 298;
X-ray effects on, vii, 253

(see also Muscle Cells, Nerve Cells, Germ Cells, etc.)

Body Fluids, ix, 50-1, 173-90;
in connective tissues, 59;
sugar in, 290, 291
(see also Blood, Tissue Fluids)
Boë, Francis de la, x, 69, 70, xvi, 108

Boerhaave, Hermann, x, 76-7, 87, xvi, 112, 178

Boer War, kopjes in, xiv, 82
Boethius, xvi, 101
Bog Iron Ore, iii, 13, viii, 156
Bog Mosses, xiii, 68-9
Bogoslof Islands, xiv, 319
Bog Plants, xiii, 104, 381-2
Bogs, formed from filling lakes, xiv, 210-12
Bohemian Glass, viii, 281

Boiler Explosions, caused by electrolytic corrosion, vi, 64-6;
due to scale, xiv, 147;
violence, v, 140
Boilers, Steam, v, 139-42;
boiling point of water in, viii, 303;
hard water in, 151-2, 323, xiv, 147;
heat loss, v, 155;
pressure in, iv, 119, 170
Boiling, of foods, xv, 233;
of liquids, iv, 167-75
Boiling Point, iv, 168;
chemical composition and, viii, 298, 301;
in various thermometers, i, 73, iv, 136, 137, 141, viii, 27;
of various substances, iv, 173;
pressure effects on, 168, 169-70, v, 354, viii, 303-5

Boils, causes of, ix, 186, 187, x, 195, 201, 311

Bolivia, Chilean control of, xiv, 306
Bologna, University of, xvi, 100;
medical school of, x, 38
Bolometers, iv, 301, vii, 363;
in corona studies, ii, 212, 225
Bombay Duck, xii, 163
Bombing Machines, v, 233
Bombs, aerial, v, 372-3
Bombs, volcanic, xiv, 323
Bond, Dr. A. R., author Mechanics, Vol. v
Bonds (chemistry), defined, viii, 374
Bone Black, viii, 47
Bone Fertilizers, viii, 153, 280, 343
Bones, of body, ix, 59, 71;
cartilage beginnings of, 58;
condition of, in infants, 345-6;
food needed for, 33;
formation, structure, and growth, 54-7, 58;
inflammations of, x, 224;
lime salts in, ix, 57;
red marrow of, 183;
used in hearing, iv, 204;
X-ray pictures of, iv, 320, vii, 253-4, 255
Bonneville, Lake, iii, 153
Books, ancient making of, xv, 178-9;
printing and binding of, v, 306
Book Scorpions, xii, 90
Boomerangs, xv, 194, 208;
principle of, iv, 42
Bora Winds, i, 133, 368
Boracic Acid, viii, 89, 90, 372
Borates, preparation, viii, 117;
test, 290
Borax, composition, viii, 141;
deposits, 89, 90, 197, 275;
uses, 89, 141, 146, 333, 372
Boredom, in work, xi, 275-6, 277-8, 280
Borelli, Giovanni Alfonso, x, 70, 71-2, 83
Boric Acid, natural sources, viii, 90, 118;
preservative, 89, 333, 372;
solid, 114
Boring Machines, v, 44, 376
Boring, deep, xiv, 11, 12
(see also Wells)
Borneo, continental island, xiv, 274;
coconut gathering in, xii, 378;
orang-utan of, 381;
rhinoceros of, 306;
sun bear, 337;
tattooing in, xv, 259;
tribal morality in, 374
Boron, viii, 19, 89, 90;
atomic weight and symbol, 383;
in silicates, 193
Bosphorus, importance to Russia, xiv, 267
Boston, drumlins near, xiv, 60;
harbor of, 269;
sewage disposal, viii, 326;
water supply, 317, xiv, 140
Boston Ivy, xiii, 28
Botany, Volume xiii
Botany, xvi, 36;
binomial nomenclature in, x, 84;
daily interest, xvi, 20-2;
discovery of America, effects, x, 45;
history of development, xvi, 112, 116, 165-7;
public education in (France), 22
Bothnia, Gulf of, salinity, xiv, 296
Bow-and-Arrow, evolution of, xv, 213-15;
fish-shooting with, 227;
stringed instruments developed from, 317-18
Bowditch, Henry Pickering, x, 131
Bowels, care of, x, 316-17;

"yearning of," xi, 64, 131, 160 (see Intestines)

Bowfin, xii, 152;
nests of, 154
Bowlder Clay, iii, 67, xiv, 59

Bowlders, glacial, iii, 70, 237, 352 (pl. 20), xiv, 69, 70

Boyle, Robert, air pressure experiments, iv, 29, 125;
chemical work, xvi, 110, 111, 112, 115, 119, 177;

"Sceptical Chemist," quoted, 159

Boyle's Law, iv, 125-6, 133, 143, 156, viii, 106-7

Boys, education of, xi, 266-7;
food consumption by, viii, 367
Brachiopods, iii, 259, 263, 270-2, xii, 47-8;
deep sea 23;
illustration, iii, 256 (Pl. 14)
Bracken Fern, xiii, 350
Bracts, xiii, 43, 45, 206

Bradley, James, astronomical work, ii, 90-2, xvi, 124

Brahe, Tycho (see Tycho Brahe)
Braided Goods, v, 276-7
Brain, ix, 131, 144-7, xi, 15-32, 60;
areas for different functions, xv, 89-90;
as seat of life, ix, 11, 14, 17;
association fibers, xi, 200;
association region of, ix, 151;
auditory area, xi, 108;
blood supply of, ix, 197, 216-17;
cells of, 14;
changes caused by shock xi, 59;
condition of, at birth, ix, 351;
connections in nervous system, 142-4, 147-51;
convolutions of, xv, 62-3;
delayed nervous impulses in, ix, 140, 141-2, 145, 146-7;
diseases, results of, 146;
emotional processes in, 154, 200;
gray matter of, xv, 63;
in dreams, xi, 301;
in sleep, ix, 218, xi, 285, 286, 287, 289;
inflammation of, cause, x, 224;
insensitive to pain, xi, 118;
intellectual processes, ix, 147-53, 154;
magnetism effects, vii, 247;
mental incapacity from defects, xi, 13;
motor area, ix, 147;
of insects, xii, 103;
of men and lower animals, compared, xv, 62-3, 96;
of primitive men, iii, 302-3, 304, xv, 89-91, 96;
various animals of past, iii, 289, 290, 292, 298, 299;
overuse effects, xi, 288-9;
protection of, in infants ix, 345;
Sherrington on, xi, 12;
skull capacity in relation to, xv, 41;
stomach and, relations, xi, 370;
storehouse of past environment, 58;
tissues unaffected in starvation, ix, 298;
visual area, xi, 96-7;
waste of energy of, 377;
weight in man and apes, xv, 62;
weight in various men and races, 39-41;
wounds of, early treatment, x, 55, 56
(see also Brain Stem, Cerebellum, Cerebrum)
Brain Case, ix, 61;
face and, xv, 43, 62

Brain Power, development of, in man, xv, 190-1;
racial expressions and, 39, 63-4
Brain Stem, ix, 144-5, 146 (fig.);
vital process centers of, 167-9, 257, 315
Brain Work, energy consumed by, viii, 367;
fatigue from, ix, 138, x, 247
Brain Workers, ailments, xi, 371;
attractive foods for, ix, 242;
exercise needs, x, 304
Brakes, air (see Air Brakes);
electromagnetic, vi, 92, 94;
friction, iv, 93-4;
regenerative, vii, 200

Bramah, Joseph, hydraulic press, v, 98-9, 376;
planer, 377
Bran, in diet, x, vitamines in, 261, 266
Branches of Trees, as leaves, xiii, 378, 379;
why clear of ground, 86
Brandes, H. W., i, 215
Brasher, Philip, v, 124-5
Brass, alloy of copper, viii, 156, 164, 273;
electrical conductivity, iv, 283;
electric welding of, 312;
expansion and contraction of, 145-6, v, 72
Brave West Winds, i, 128, 368
Brazil, bushmaster snake of, xii, 234;
butterfly orchid of, xiii, 145;
coasts, xiv, 257;
coffee production, xiii, 232, 233;
coral reefs on coast, xiv, 305;
forests, xiii, 365, xiv, 366;
frogs of, xii, 178, 179;
glacial and coal deposits, iii, 203, 204;
interior unexplored, xiv, 26, 250;
jaguarundi of, xii, 364;
lizards of, 208;
matamata of, 193;
public health scholarships, x, 172;
rubber production, xiii, 246-7, 248;
shirt tree of, xv, 256;
soil depths, iii, 26;
tea cultivation, xiii, 228;
wolf of, vii, 342;
yellow fever in, x, 163
Brazilian Basin, xiv, 289
Brazilian Current, xiv, 304
Brazil Nut, source, xiii, 266
Bread, chemistry of, viii, 368-9;
digestion of, x, 326;
food value of, viii, 364, ix, 34-5, 299, x, 267, 268, 269, 273;
rising of, due to bacteria, 194;
yeast action in, ix, 248
Breadfruit, origin, xiii, 224
Breadfruit Trees, xv, 124
Breakwaters, pneumatic, v, 125;
strength of, xiv, 300, 301
Breath, holding of, ix, 256-7, 266;
holding of, in infants, 348;
shortness of, in heart failure, x, 340-1;
smell of, ix, 97;
soul in, savage idea of, xv, 330

Breathing, action and control of, ix, 256-8, 263-6, x, 339;
body heat regulation by, 251;
color effects on, xi, 96;
deep, value of, ix, 259;
deep, sensations from, 266-7;
how learned, xi, 36-7;
in fatigue, 272;
in sleep, 283;
muscles of, in voice production, ix, 83;
of insects, xii, 103;
periodic, x, 339-40;
quickened by exercise, 303;
rate of, in infants, ix, 347-8;
rib cage movements in, 65;
through mouth, effects, x, 341-2
(see also Respiration)

Breeding (animal and plant), blended inheritance and pure breeds, ix, 337;
in ancient Egypt, xvi, 72;
in captivity, xv, 197;
selective, ix, 327, xvi, 157-8
Brennan, Louis, v, 342
Brenner Pass, xiv, 240-1
Bretonneau, Pierre, x, 106, 110
Brewing, chemistry of, viii, 249
Bricks, invention of, xv, 268;
making of, in Egypt, 267 (fig.)
Bridges, steel, electrolysis in, vi, 64, 66;
strains on, v, 194;
sympathetic vibration of, iv, 225
Briggs, Henry, xvi, 104

Bright's Disease, x, 112, 225, 335, 340-1, 345, 346

Bristol Channel, tides of, xiv, 293
British Columbia, fjord coasts, xiv, 258;
no volcanoes or earthquakes in, 315, 331
British Gum, viii, 243
British Meteorological Office, i, 222;
aeronautical service, 230, 286;
forecasts, 241;
in World War, 310

British System of Units, iv, 46, 69-70, 79, 80

British Thermal Unit, iv, 154, v, 350-1;
erg and calorie equivalents, vii, 382
Brittle-stars, xii, 23, 49
Broadway, N. Y., display lighting vii, 340-1
Broca, Paul, x, 130
Brocken Specter, i, 184, 185, 382
Bromine, a halogen, viii, 18, 84;
atomic weight and symbol, 383;
manufacture, 274;
properties and uses, 84-5, 86, 181, 297-8, 333;
test, 290

Bronchial Tubes, as infection center, x, 220, 224;
defence against germs, 202;
subdivisions of, ix, 255
Bronchitis, causes, x, 253, 295
Brongniart, Adolphe, 167, 169
Brontides, i, 195-6, 368
Brontosaurus, xii, 195
Brooklyn, water supply of, xiv, 140
Brooklyn Bridge, completion, v, 382;
corrosion of, vi, 66
Brooks Comet, ii, 134, 275, 286
Brook Trout, xii, 159
Broths, viii, 362, 369
Brounov, Prof. P., i, 249
Brown, John, medical work of, x, 89-90
Brown, Robert, xvi, 166
Brownian Movements, viii, 314, xvi, 166
Browning John M., v, 363, 366-7
Browning Machine Gun, v, 366-7, 384
Brown Paper, making of, v, 294;
source, xiii, 240
Brown Race, xv, 32;
diseases of, 51;
peoples of, 37;
separate origin theory, 70
Bruce, James, xvi, 123
Bruce Telescope, ii, 136, 302
Brush Discharge, vii, 10-11, 363
Brushes, dynamo, vi, 178, vii, 363
Brussels Sprouts, xiii, 197, 222;
mutant nature, 333-4
Buansuah, xii, 345
Bubonic Plague, x, 163-7;
native immunity to, xiv, 357;
Paré and, x, 153;
prevention of, 171;
spread by lice, 311
Buckwheat, xiii, 56;
family, 194;
flower, 46;
food, viii, 364;
life of, xiii, 53
Budapest, deep drilling, iii, 120-1
Buddhism, development of, xv, 199;
Nirvana of, 334
Buds, never on roots, xiii, 22, 23, 29;
of perennials, 53
Buenos Aires, harbor of, xiv, 270

Buffalo, N. Y., electric power system, vi, 377-8

Buffalo Bugs, xii, 123
Buffalo Dance, xv, 305-6
Buffaloes, xii, 328-9;
of Great Plains, xiv, 383
Buffalo Grass, xiii, 374
Buffalo Hot Springs, xiv, 145

Buffon, founder of modern natural history, xvi, 128;
lightning experiments, vi, 15;
"Natural History," xvi, 116;
on evolution of species, 139-40, 148
Bugles, sounding of, iv, 231
Bugs, xii, 110-14;
jaws and maxillæ in, 100
Buildings, development of, xv, 266-72;
dryness of air in American, i, 322, 323;
earthquake construction, xiv, 342, 343;
electric wiring, vii, 55-65;
weathering effects, iii, 22, 24
Building Stones, iii, 370-2
Bulgaria, long life of peasants, xiii, 172
Bull Durham Sign, Broadway, vii, 341
Bullets, form and flight, v, 362, 365
Bullfrogs, xii, 180-1
Bumps, in aeronautics, i, 293, 298, 368
Bunch Grass, xiv, 380
Bunsen, carbon arc, xvi, 189;
chemical work, 163;
solution of spectrum lines, ii, 112
Bunsen Burner, viii, 60-1
Buoyancy, law of, iv, 103-4, 105;
of air, 107, 108
Burbank, Luther, xvi, 167
Burdock, seed dispersal, xiii, 58
Burette, viii, 294, 295 (fig.)
Burma, elephant of, xii, 302;
rivers of, xiv, 195-6;
viper of, xii, 230
Burning Oils, viii, 209
Burns, of body tissues, x, 252;
from X-rays, vii, 250, x, 254
Burrels, xii, 326
Burs, chestnut and beech, xiii, 193;
seed dispersal by, 343
Bus Bars, vi, 358-9
Bushland, xiv, 378-9, 380, 381
Bushmen (African), xv, 133-5;
art of, 119 (fig.), 120-1, 298-300;
civilization at collection stage, 196;
hair of, 38;
height of, 39;
ostrich-hunting of, 212, 222;
use of baboons, in water searching, xii, 380
Bushmen (Australian), iii, 304
Bushnell, David, v, 197
Butane, derivatives, viii, 210
Butcher's Broom Plant, xiii, 29-30
Butte Mining District, iii, 361, 368
Butter, calory value, ix, 299, x, 269, 273;
composition, viii, 364;
digestion of, x, 326;
made by electricity, vii, 226, 227, 228;
pure food, ix, 300;
substitutes for, viii, 363, 364, x, 262, 267, 268;
vitamines in, 259, 261, 267
Buttercup Family, xiii, 196
Buttercups, double, xiii, 51;
petal arrangement, 190
Butter Fat, viii, 245, 246, 364;
in milk, 363;
vitamines in, 369
Butterflies, xii, 114-18;
antennæ of, 101;
earliest appearance, iii, 279, xii, 104;
evolution of, xii, 106-7;
jaws and maxillæ in, 100;
number of species in N. Y., 99, origin of name, xv, 157;
plant fertilization by, xiii, 123-4, 133-5, 142-3

Butterfly Orchid, xiii, 145
Buttes, made by erosion, iii, 140
Buttonball Tree, xiii, 343-4
Buttonhole Machine, invention, v, 382
Butyric Acid, viii, 220, 248
Buys Ballot's Law, i, 125, 134
Buzzards, xii, 261
Buzzards Bay, oysters of, xii, 61;
tidal race at, xiv, 294
Byron, skull capacity, xv, 40
Byssus, xii, 64
Cabbage, calories in, ix, 299;
in mustard family, xiii, 197;
origin and antiquity, 222;
sport plant, 333-4;
vitamines in, x, 261, 262
Cabbage Bug, xii, 114
Cables (ocean), breaks in, xiv, 284;
laying of, 283,
(See also Atlantic Cables)
Cables, underground, vii, 12-13, 27
Cabot, John, birth and training, xiv, 310
Cacao, xiii, 234, 235
Cachalot, xii, 298-9

Cactus, characteristics of, xiii, 378, xv, 19;
leafless forms, xiii, 15;
leaves of, 378, xiv, 378;
prickly pear, xiii, 29 (fig.);
regions of dominance, 355;
stems of, 31;
water-storage by, 28, 106, 379
Cactus Family, xiii, 200;
restricted area, 320
Caddis Flies, xii, 106
Cadmium, symbol and atomic weight, viii, 383;
test for, 287, 288
Cæsar, Julius, scientific reforms, xvi, 98

Cæsarian Section, ancient practice of, x, 14, 27

Cæsium, chemical properties, viii, 128, 132, 133, 383;
spectrum, 302
Caffeine, composition, viii, 230;
polyuria induced by, x, 344
Caffre, xii, 355
Caimans, xii, 198
"Cain," picture, xv, 69
Caissons (pneumatic), iv, 30-2, v, 116-21;
pressure in, i, 329, iv, 129
Cake Urchins, xii, 50
Caladium, leaves of, xiii, 79
Calamus, of India, xiii, 361
Calamus Root, xiii, 188, 255
Calcite, iii, 325-6;
gangue mineral, viii, 199;
light polarization by, iii, 319, iv, 354
Calcium, viii, 148-9;
affinities, 31-2, 101-2, 128;
atomic weight and
symbol, 383;
compounds, 130, 138, 149-53, 195;
compounds in hard water, 318, 322-4;
electrolytic production, vii, 320-1;
fusibility, viii, 384;
in body tissues, 354;
in earth's crust, iii, 308, viii, 19, 129, 192, 195, 196;
in light metal group, 17, 127;
plant needs of, viii, 337, 341, 344;
specific gravity, 384;
test for, 287, 289
Calcium Carbide, viii, 153;
acetylene prepared from, 231;
in nitrogen fixation, 74, i, 36;
production and uses, vii, 312, xvi, 191
Calcium Carbonate, viii, 151-2;
composition, 117;
deposits of, 195;
lime from, 149, 150;
in soil sweetening, 150, 347;
in water, 40, 151, 322.
(See also Limestone)
Calcium Chloride, viii, 152-3, 322-3;
mixture with snow, iv, 175
Calcium Group, viii, 148-53;
spectra, 302
Calcium Hydroxide, viii, 150, 347
Calcium Light, compared with sun's, ii, 169
Calcium Oxide, viii, 149-51. (See Lime)
Calcium Pentasulphide, viii, 333
Calcium Phosphate, viii, 89, 153, 279-80, 354
Calcium Stearate, viii, 143, 323
Calcium Sulphate, viii, 117, 149, 153;
in water, 40, 322-3
Calcium Sulphite, viii, 153, 372
Calcium Tungstate, color in X-rays, iv, 378
Calc Spar, iii, 325

Calculations, mathematical, development of, xv, 181-4, xvi, 61

Caldwell, Kansas, region, iii, 34
Calendar, Babylonian, xvi, 57-8;
Bacon's work, 101;
clothing in relation to, x, 309;
Egyptian, xvi, 70;
reforms of Cæsar, 98
Calibration, vii, 158, 363;
of condensers, 293-4
California, aerial fish patrol, i, 48;
Big Trees (see Big Trees);
borax deposits, viii, 89-90;
climate, xiv, 348-9, 358;
climatic changes in, 361, 362;
cretaceous deposits, iii, 216;
crustal movements in southern, 81-2, 225;
earthquakes and volcanoes, xiv, 331;
forests and trees, 374;
geese of, xii, 258;
gold production, iii, 226, 365, 367;
hot springs, xiv, 143;
live oaks of, 370;
lemon trees of, xv, 22;
mercury production, iii, 370;
ocean waves used for power, v, 174;
oil fields, iii, 350;
rainfall, i, 112;
raisin-drying industry, v, 257;
record temperature, 209;
redwood forests, fog drip, 351;
"road-runners" of, xii, 265;
sea elephant of, 335;
sea lions, 334;
southern, xiv, 42;
"Sunshine State," 86;
tin production, iii, 368;
valley of, xiv, 215
Callao, harbor of, xiv, 265
Callina of Spain, i, 96, 368
Calms of Cancer and Capricorn, i, 129, 368
Calomel, viii, 170
Caloric, iv, 47, 154, xvi, 125

Calories, definition and value, iv, 154, 312, vii, 369, viii, 361, 374, ix, 295, x, 269;
electrical equivalents, vii, 382;
food requirements in, ix, 296-7;
in various foods, viii, 361, 366-7, ix, 299, x, 269;
major, viii, 361;
mechanical equivalent, ix, 295;
use of, in rating food values, iv, 48
Calorimeter, viii, 360-1, x, 269

Calumet Copper Mine, heat increase in, xiv, 12

Calyx, xiii, 44, 45;
absent in some plants, 46, 182;
incorporated in fruits, 54
Camber, of aeroplanes, i, 288
Cambium, xiii, 24, 26, 177 (fig.)
Cambrian Period, iii, 181-4, 377;
animals of, 263, 267, 268, 272, 273, 277;
climate, 184-5;
first life in, xv, 71;
fossils from, iii, 174;
metamorphism of rocks in, 189
Cambridge University, founding of, xvi, 100
Cambyses, burial of army of, iii, 73
Camels, xii, 313-15;
hoofs of, iii, 300;
trypanosome in, x, 168
Camera, iv, 339-40, ix, 106-9;
Langley on the, ii, 221;
power to pierce water, i, 47
Camphor, viii, 240, 252;
in celluloid, 255;
smell, xi, 80;
source, xiii, 255, 263
Cams, v. 39-40

Canada, animals of, xii, 287, 318, 320, 336, 348, 350, 351, 365;

Atlantic ports closed by ice, xiv, 267;
forests of, 371, 372;
French colonization of, 191;
geology, iii, 165, 167, 219, 231-2;
Glacial Epoch effects, xiv, 56, 61-2, 170;
Indian summer, i, 361;
lakes of, xiv, 200;
mining products, iii, 360, 365, 368, 376;
plains of, xiv, 217;
plutonic formations, 111;
rainfall of, 360;
tobacco production, xiii, 258
Canadian Rockies, formations in, xiv, 229;
glaciers of, 55
Canals, lift locks, v, 103
Canaries Current, xiv, 304
Canary Islands, xiv, 252, 289;
dragon tree of, xiii, 183-4

Cancer, cause, nature, and treatment, x, 119-20, 382, 383-4;
early knowledge of, 39, 41;
racial immunity and susceptibility to, xv, 48-9, 50, 51;
spread and cure by surgery, ix, 255
Candle, Candlepower, iv, 351-2;
compared with sun, ii, 169
Candles, blowing out of, viii, 57;
burning of, in caissons, iv, 31;
flame of, viii, 58, 59;
materials of, 247
Candy, boiling point, viii, 299;
dextrin in, 243;
glucose uses, 225
Cane Sugar, xiii, 83, 214-15;
chemical properties, occurrence, and use, viii, 226-7;
extraction and refining, 242;
fermentation, 225, 227;
large molecules, 356;
making of, by plant, 335;
solutions, freezing point, 299;
sweetness of, ix, 230;
testing of, by polarized light, iv, 356

Canned foods, vitamines lacking in, x, 262, 263, 266, 267-8

Cannel Coal, iii, 344, viii, 202
Cannibalism, remarks on, ix, 280-1
Cannon, Dr., medical work, x, 295, 327;
quoted, xi, 137-9
Canoes, primitive, xv, 262-4;
propulsion of, iv, 33-4
Canopus, gaseous state, ii, 382;
parallax and distance, 316
Canvas Buckets, use of, v, 350

Canyons, depth dependent on altitude, xiv, 159;
occurrence in dry climates, 51-2

(see also particular canyons under river names)

Caoutchouc, xiii, 245;
chemistry and manufacture, viii, 257-8 (see Rubber)

Capacity, electrical, iv, 267-8, viii, 363;
in overhead transmission, 104, 105;
in oscillating circuits, 286-7, 289;
measurement in oscillating circuits, 294-5, 296-7;
unit of, iv, 284, vii, 368
Cape Nome, Alaska, iii, 57
Capella, binary star, ii, 123;
color, 297;
solar star, 115
Cape of Good Hope, climate of, xiv, 358;
discovery of, 309
Cape Town, oak trees at, xiv, 370
Cape Verde Islands, xiv, 252, 289;
ocean deeps around, 289
Capillaries, ix, 54, 192-5;
in circulatory system, x, 63, 334;
oxygen diffusion through, ix, 260;
passage of blood through, 210, 212, 214, 215;
unknown to Galen & Harvey, x, 63

Capillarity, of soil water, viii, 37, xiii, 92-3

Capri, level changes at, iii, 81
Caproic Acid, viii, 220
Capsules, plant, xiii, 56, 69
Capuchin Monkeys, xii, 377-8
Capybaras, xii, 289
Caracels, xii, 356
Caraway Seed, xiii, 201, 265
Carbohydrate Industries, viii, 241-4
Carbohydrates, viii, 223-9, 374-5;
body fuels, xi, 271, 278;
daily consumption, viii, 366-7;
digestion and utilization of, 356, 357, 358-9;
food requirements and values, 361, 362, x, 268, 269, 271;
formation by plants, viii, 219, 335, 349, 350, xiii, 81;
storing of, in body, x, 272;
structure and hydrolysis, viii, 217-18;
use of by animals and vegetables, 246, 348, 349, 350

Carbolic Acid, viii, 238, 253, 333;
as antiseptic, x, 145
Carbon, viii, 18, 42-52;
affinity for oxygen, 12, 102;
atomic weight and symbol, 383;
chemical energy, 186-7;
colors due to, 258;
combustion of, 12-13, 308, ix, 26, 190;
diamonds and graphite pure, iii, 328, 331, viii, 42, 43;
electrical conductivity, iv, 283;
electric positiveness, vi, 59, 61;
ignition of, viii, 53;
in body, elimination, 353;
loss in fatigue, xi, 271;
in hydrocarbons, viii, 205-7, 233, 234;
in iron, v, 316-17, 319, 320-1, viii, 157, 158;
in iron preparation, 157;
in neutral refractories, vii, 307;
in organic matter, viii, 42, 64, 204, 336-7;
in proteins, 351;
in steel, 159, 160;
luminosity of flame due to, 59-60;
melting point, iv, 162;
necessity of, to life, ii, 242-3;
percentages in coal series, iii, 345;
plant uses of, viii, 49, 340-1, xiii, 14, 80, xiv, 64-5;
potential energy in, iv, 82;
production of pure, xvi, 190
Carbonaceous Matter, in soils, viii, 340
Carbonaceous Strata, iii, 249-50
Carbonated Beverages, viii, 43, 50
Carbonated Waters, natural, xiv, 142, 146
Carbonate Group, viii, 93

Carbonate of Lime, ancient layers of, iii, 250, 251;
animal shells and skeletons of, 259, 266, 267, 268, 270;
hard water due to, 126;
limestone composed of, 25, 308;
in sandstone, 27

(see also Calcite, Calcium Carbonate, Limestone)

Carbonates, formation of, viii, 49;
in blood, x, 280;
metal compounds, viii, 130, 147, 198;
metal extraction from, 131, 271;
test of, 290
Carbon Compounds, viii, 42, 48-52, 61;
optical activity, xvi, 164

Carbon Cycle, viii, 49-50, 325-6, 334-5, 349-50

Carbon Dioxide, viii, 42, 48-50;
atmospheric, i, 10, 11, 13-14, 25, 322, viii, 48, 49, 67-8, 152, ix, 26, 254;
body production and elimination, ix, 190, 248, 253-4, 262-7, 268, x, 270, 280, 281, 338, 339;
boiling and freezing points, iv, 173;
critical temperature and pressure, 172, 173;
fatigue product, xi, 270-2;
in
blood, ix, 263, 264-7, x, 331, 339;
in blood, loss in mountain sickness, i, 328;
in Carbon cycle, viii, 334, 350;
in limestone, 42, 49, 152;
in minerals, 201;
in water, 40, 111;
leavening agent, 50, 136, 137;
plant uses of, 219, 335, 347, 349, ix, 26-7, xiii, 80-1, 82, xiv, 65;
product of combustion and decay, viii, 12-13, 26, 45, 61, ix, 26, 190;
produced by fermentation, 248;
production, commercial, viii, 48, 276;
rock disintegration by, 194-5;
thrown off by lungs, 353;
vitiation of air by, 331, 332, ix, 268, x, 238

(see also Carbonic Acid)
Carbon Disulphide, combustion of, viii, 61;
light refraction by, iv, 331;
refrigeration by, 174
Carbonic Acid, viii, 48-9, 101, 115;
atmospheric content affected by light, x, 253;
chemical action on rocks, iii, 24, 25, 27, viii, 194;
critical temperature and pressure, iv, 172;
early studies, xvi, 119-20;
elimination in sleep, xi, 283;
formation in body, x, 280;
heat absorption by, iii, 248;
in ground waters, xiv, 142, 146;
in sea water, iii, 54;
in sodium compounds, viii, 134-6;
in urea, 230, x, 279, viii, 61;
light refraction by, iv, 331;
refrigeration by, 174
Carboniferous Period, iii, 197;
animals of, xv, 71;
landscape of, xiii, 320;
length and antiquity, 314, 322;
plants of, 307-11, 315-17
Carbon Monoxide, viii, 50-1, 157
Carbon Tetrachloride, vi, 101, viii, 212
Carborundum, chemical composition, 90;
discovery, manufacture, and uses, vii, 300, 301, 309-11, xvi, 190;
refractory, vii, 308, 311;
in wireless detectors, 269
Carboxyl Group, viii, 220, 375
Carbuncles, cause of, x, 195, 311
Carburetors, vii, 124-8;
mixtures in, v, 156
Caribbean Sea, hurricane reports, i, 282, 309
Caribe (fish), xii, 159-60
Caribou, xii, 320;
horns of, 316
Carlsbad, Bohemia, xiv, 145, 152
Carlyle, dyspepsia of, xi, 369;
on work, 276;
on shame and clothing, x, 306

"Carnegie," magnetic survey ship, i, 193, vi, 39

Carnelian, iii, 337
Carnivorous Animals, xii, 332-65
(see also Flesh-eating Animals)
Carnot, mathematician, xvi, 125;
on heat, 135
Carolina Parakeet, xii, 266
Carolina Poplar, as index plant, i, 255
Carps, xii, 161

Carrel, antiseptic methods, x, 146, 181-3, 382

Carrel-Dakin Solutions, x, 181-3, 382
Carrion Crow, xii, 260
Carroll, Dr. James, x, 160, 161, 200
Carrots, flowers of, xiii, 49;
origin, 222;
swelled roots, 19;
taproot of, 17 (fig.);
vitamines in, x, 262, 266, 268;
wild, xiii, 353-4
Carthage, and Rome, xiv, 307;
destruction of fleet before, xv, 232
Carthaginians, elephants of, xii, 302;
in Iberian group, xvi, 49
Cartilage, ix, 57-8;
making of, 54;
rib connections made of, 71;
skeletons of, xii, 142
Cartridges, explosion of, v, 157;
hydraulic, 100;
lampblack, i, 33;
modern, v, 362, viii, 145, xv, 218
Cartright, power loom, v, 376-7, xv, 246
Cascade Mountains, cirques of, iii, 66;
Columbia river canyon, 39, xiv, 165-6;
former volcanic activity, iii, 226;
geology of, 106, 139, 213-14, 226, 227;
glaciers of, 60;
lakes, 143;
precipitation on opposite sides of, xiv, 355;
snowfall, i, 119;
volcanic cones of, xiv, 100-1, 225, 315
Casein of Milk, food value, x, 259, 278

Caspian Sea, area and depth, iii, 154, xiv, 204;
commercial importance, 212;
formation of basin, iii, 154, xiv, 203, 205;
monsoons, i, 131;
salinity, iii, 154-5, viii, 139, xiv, 206-7

Cassini, Domenico, astronomical work, ii, 13, 59, 85, 133, 227-8;
telescopes, 59, 99

Cassiopeia distortion from sun's motion, ii, 306;
new star in, 331
Cassiterite, iii, 326, 369
Cassowaries, xii, 243, 249
Castillo, Grotto of, xv, 100 (fig.);
picture from, 112
Castings, of different metals, iv, 150
Cast Iron, v, 316, 319, 320-2, viii, 157, 158
Catalan Forge, v, 315;
air compression for, 89
Catalpa Trees, xiii, 271-2
Catalyzers, viii, 102-3, 375;
discovery, xvi, 165;
effect on speed of reactions, viii, 310, 311;
enzymes as, 103, 357;
various applications, i, 36-7, viii, 81, 82, 86, 174, xvi, 165

Cataphoretic Medication, vii, 247-8
Cataract, of eyes, ix, 112, 116, x, 41;
ancient operations for, 27
Catarrh, germ of, x, 221
Catastrophism, xvi, 149
Cat Briers, xiii, 188

Caterpillars, xii, 115-16, 117 (fig.), 118, 119;

"rains" of, i, 356-7
Caterpillar Tractors, v, 216-18, 383
Catapults, xv, 219
Cat Family, xii, 354-65
Catfishes, xii, 161-2
Cathode, defined, iv, 317, 382, vii, 251, 363
Cathode Rays, iv, 317-18, x, 184;
discovery and nature, xvi, 193;
fluorescence from, iv, 380
Cathode Stream, vii, 252
Cation, defined, iv, 382

Catkin-bearing Trees, fertilization of, xiii, 148

Catkins, xiii, 190, 192, 193-4
Catnip, flowers of, xiii, 205
Cats, xii, 354-56;
body heat, conservation of, ix, 307;
embryological resemblance to dog, xv, 54;
hair erection in, ix, 161, 164;
instincts of, xi, 48
Catskill Aqueduct, v, 262, 263-5
Catskill Formation, iii, 195

Catskill Mountains, formation, iii, 139, xiv, 179, 225;

New York water supply from, xiv, 140;
section of, iii, 138 (fig.);
stream piracy in, xiv, 179-80
Cat-tails, xiii, 59, 181, 187
Cattle, domestic, origin of, xii, 330;
elastic cord in neck, ix, 59;
hornless, breeding of, 327;
salt consumed by, viii, 140;
surra disease of, x, 168;
tetanus germ in, 298-9;
tick diseases of, xii, 98;
ungulates, 300;
young of, ix, 346
Cattle Family, xii, 324-31
Cattle-raising, on grasslands, xiv, 383-4
Cattle-Raising Stage, xv, 187, 196-9
Caucasus Mountains, iii, 236;
Ice Age in, 240;
recent formations, xiv, 235
Cauliflower, a modified bud, xiii, 41;
in mustard family, 197;
origin, 222;
sport plant, 333-4
Caustics, x, 255
Caustic Soda, viii, 278
Cauterization, batteries used, vii, 242;
former use of, x, 38, 55, 56
Cavalieri, Bonaventura, xvi, 104, 119
Cave Bear, xiv, 149;
cave pictures of, xv, 110 (fig.);
relics of, 79, 82, 100 (fig.)
Cave Fishes, eyes of, xii, 138
Cave Lions, xii, 359
Cave Men, xv, 76-84, 88-102;
art of, 148-9, xv, 110-20, 298, 299, 300;
clothing of, 257;
life of, 188-91;
tools and weapons, 102-10

Cavendish, Henry, chemical work, xvi, 120, 121, 177;
electrical work, vi, 16, 17, xvi, 121;
experiment to prove gravitation, iv, 98;
hydrogen discovery, results, x, 89
Cavendish Experiment, ii, 68

Caves, Caverns, formation in limestone, iii, 127, viii, 151, xiv, 147-8;
importance in history of man, 148-9, xv, 266;
primitive life in, 80-1, 82-3;
wind-eroded, iii, 73
Caviar, acquired taste for, xi, 72;
sources of, xii, 151, 152
Cavies, xii, 289
Cavitation, v, 235-6
Cayuga, Lake, xiv, 203
Cazorla, Spain, hailstorm, i, 119
Ceiling, of aeroplanes, i, 303
Celebes, xiv, 274;
animals of, xii, 310, 330, 379
Celery, blanching of, xiii, 76;
calories in, ix, 299;
family, xiii, 200-1;
origin and antiquity, 222
Celestial Equator, ii, 70
Cell Metabolism, ix, 37-40;
oxygen requirements, 182, 199, 253, 254, 260;
part of cell engaged in, 42-3;
sugar and fat supplies, 289;
supply system, 49-52

(see also Metabolism, Basic Metabolism, Functional Metabolism)

Cells (electric) see Electric Cells

Cells (organic), basis of life, ix, 12, x, 119, xii, 10, 14, 25, xiii, 74, xv, 16, xvi, 142;
dynamics of, xvi, 144-5;
growth by division of, ix, 43-8, xiii, 166-7;
living and nonliving, ix, 12-17;
maintenance and growth, 34-6;
metabolism of (see Cell Metabolism);
motions of, ix, 73-4;
of plants, viii, 337, 338, 352, ix, 26;
reproduction from, 43, 324-5, 332-3, x, 228, 232, xiii, 166-7, xv, 54, xvi, 155-6, 157-8;
size of, ix, 49;
substance of, (protoplasm), 13
(see also Body Cell)
Celluloid, composition of, viii, 255

Cellulose, viii, 223, 227-8, 229, 254-6, ix, 30;
as food, 30;
industrial uses, viii, 229, 241, 254-6, 261;
in plants, iii, 344, viii, 49, 223, 335, 348, 349, ix, 30;
in wood composition, iii, 345, viii, 44, xiv, 65

Celsius, thermometer of, iv, 136
Celsus, A. Cornelius, x, 27, 43;
on sleeping sickness in Rome, 301;
rediscovery of "De Re Medicina," 44
Celtic Languages, xv, 162
Celts, of Ireland, xvi, 49
Cement, chemistry of, viii, 280;
manufacture, iii, 373-4
Cement Floors, in factories, xi, 361-2
Cement Gun, v, 136
Cementite, viii, 160, 273
Cement Plants, potash from dust, viii, 279;
smoke precipitation, vii, 347-8
Cenozoic Era, iii, 20, 377;
animals of, 284, 293, 295, 298-301;
birds developed in, 297;
divisions and surviving species, xv, 71;
in North America, iii, 221-48;
plants in, 256, 257-8
Centaurus, "coal sack," ii, 352;
star cluster, 336-7
Center of Gravity, iv, 99-101;
tendency of wheels to turn on, v, 150
Centers of Action, i, 218, 241-2, 368;
Iceland area, 361

Centigrade Thermometer, i, 73, iv, 136, 137, viii, 27;
comparison with other scales, iv, 137, 141, viii, 27, 384

Centimeter-gram-second System, iv, 46 (see Metric System)

Centipedes, xii, 87-8

Central America, animals of, xii, 198, 208, 276, 289, 349;
coasts, coral reefs on, 40;
rainfall and rivers, xiv, 135, 195;
volcanoes of, 315, 316, 325-6, 338
Central Asia, antelopes of, xii, 327;
climatic changes, results of, iii, 75, xiv, 361, 362;
cradle of human race, xvi, 46;
desert basins, xiv, 215, 217, 355;
flowers of, xiii, 202;
horses of, xii, 306-7;
manual of, 356;
marriage custom of, xv, 282;
migrations from, xiv, 362;
oases of, 150-1;
plains of, 215;
rock weathering in deserts, 79;
rodents of, xii, 294;
salt lakes of, xiv, 199
Central Nervous System, ix, 129-32;
at birth, 348-9;
connections with glands and smooth muscles, 159-60, 162-3;
in the chordata, xii, 128;
preferred pathways of, ix, 134
Central Park Obelisk, iii, 23, xiv, 78-9
Central Sun Hypothesis, ii, 305
Centrifugal Force, iv, 71-5;
of earth's rotation, ii, 69, iv, 74-5, 101
Centrifugal Pumps, vi, 363
Centrifugal Railroads, iv, 74
Centripetal Force, iv, 72-3

Century Plants, single flowering, xiii, 43, 53;
sisal from, 240-1;
water-storage by, 41

Cephalopods, iii, 20, 260, 273-6, xii, 58, 74-80

Ceraunographs, i, 163, 368
Cereal Dusts, i, 63
Cereals, best grown in grasslands, xiii, 373;
evolution, iii, 257;
food value, viii, 364;
fruits for seed dispersal, xiii, 56, 182;
phosphate requirements, xiv, 67;
vitamines in, x, 260, 262

Cerebellum, ix, 144 (fig.), 145, 146 (fig.), xi, 28, 31;
locomotion control through, ix, 156, 158, 167

Cerebrospinal Fluid, xi, 29

Cerebrospinal Meningitis, antiserum treatment, x, 218;
germ of, 216
Cerebrum, ix, 144, 145-7, xi, 28, 29, 31-2;
at birth, ix, 351;
auditory area, xi, 108;
locomotion action of, ix, 157, 158;
seat of thought processes, 167;
visual area, xi, 86
Ceres (planet), discovery, ii, 255
Cerium, atomic weight and symbol, viii, 383
Ceylon, animals of, xii, 201, 302, 328;
chocolate production, xiii, 234;
cinnamon production, 263, 264;
coco palm of, xv, 125;
leeches of, xii, 56;
pearl fisheries of, 62;
polyandry in, xv, 286;
quinine production, xiii, 251;
tea cultivation, 228, 224 (illus.)
Chagres River, xiv, 195
Chahas, xii, 256-7
Chain Pump, iv, 26
Chain Reflex, xi, 39;
in habit formation, 250-1
Chain Structure, viii, 233, 375
Chalcedony, iii, 337
Chalcocite, iii, 326, 360, 361
Chalcopyrite, iii, 326, 360, 361
Chaldean Eclipse Cycle (see Saros)
Chaldeans, astronomy of, ii, 9, xvi, 57, 58
Chalk, iii, 377;
deposits of, 216-18, 266
"Challenger," voyages of, xiv, 283, xvi, 142

Chambered Nautilus, iii, 273-5, xii, 76, 77 (fig.)

Chamberlens, obstetricians, x, 79-80
Chameleons, xii, 204, 207-8, 208-10
Chamois, xii, 325
Champlain, Lake, formation, iii, 155
Champlain Sea, iii, 150, 151
Change, Albanian story of, v, 251;
attention attracted by, xi, 229, 344;
Cardinal Newman on, xiii, 325-6;
Heraclitus on, xvi, 79;
in earth's features, xiv, 28-30;
need of outside influence, viii, 113;
physical and chemical, 14-15
Channels, aerial mapping, i, 47;
dredging of, v, 257-8
Chaparral, xiv, 379

Characters, Characteristics, inheritance laws, ix, 333-8, x, 230-2, 233-4, xiii, 332, xvi, 154, 156, 157-8;
inherited and environmental, x, 228-9;
racial, xv, 36-52
(see also Acquired Characters, Heredity)
Charades, xv, 169
Charcoal, viii, 44;
combustion of, 12-13;
glow of burning, 57;
heat from, 186;
heat resistance, vii, 308;
in gas masks, viii, 47-8, 263, 264;
in gunpowder, 145
Charcot, Jean Martin, x, 360, xvi, 184

Charges, Charged Bodies (Electricity), iv, 256-67, vi, 284-302,
vii, 363;
chemical production of, iv, 271-2;
discharge of, 262, 264-5, 267, 269, vii, 209, 366;
discovery of laws, xvi, 121;
electrical condition, i, 142;
electricity on surface, iv, 282;
induced, 260, vii, 370;
leakage, 371;
measurements and units, iv, 260-1
(see also Electrification, Ionization)
Charlemagne, clock of, v, 62;
Vikings and, xiv, 261

Charles II, founder of Greenwich Observatory, ii, 83, xvi, 124

Charles's Law, iv, 140, viii, 107-8
Charleston (S. C.) Earthquake, iii, 95, 97-8
Charleston (W. Va.) region, iii, 34
Charts, marine, i, 271-6;
meteorological, 206-8;
phenological, 254;
synchronous and synoptic, 214-15
Chautauqua, Lake, origin, iii, 145-6
Chaucer, "Doctor" of, x, 41;
language of, xv, 156
Chauliac, Guy de, x, 39, 40-1
Checkered Adder, xii, 222
Cheese, calories in, ix, 299;
composition and value, viii, 363;
manufacture of, xiii, 71
Cheeta, xii, 365
Chellean Implements, xv, 105, 106-7
Chemical Affinity, viii, 12;
electrical nature, xvi, 122;
electromotive series, viii, 127-9;
intensity measured by heat, 308, 360;
of metals for nonmetals, 20;
source of energy, 267, 268
Chemical Changes, nature of, viii, 9-15, 188;
signs of, 100-1
Chemical Compounds (see Compounds)
Chemical Elements (see Elements)
Chemical Energy, viii, 12, 186-7, 267, 268;
electricity from, 167-8
Chemical Equations, viii, 13, 94-6, 376
Chemical Industries, viii, 241-84
Chemical Reactions, viii, 99-105;
defined, 381;
equations of, 94-6;
equilibrium, 103-5, 190-1;
heat of, 308;
reversibility, 21, 101;
of solutions, 36, 37, 119-25, 311;
speed of, 310-11;
types, 20-1
Chemical Warfare, viii, 262-4, x, 186-8
Chemical Warfare Service, x, 187-8;
device, viii, 233
Chemistry, Volume viii
Chemistry, beginnings of modern, viii, 34;
concrete science, xvi, 42;
daily interest of, 13-15;
defined, viii, 11, xvi, 36;
difficulties of study, viii, 10-11;
exact, positive science, x, 368;
former realm, xvi, 14;
historical development, 54, 59, 73-4, 109, 110, 112, 115, 119-21, 133-4, 159-65;
medicine and, x, 81, 369;
nomenclature, viii, 97-8;
subjects dealt with in, iv, 12;
ultimate identity of organic and inorganic, x, 69

Chemosynthetic Organisms, xii, 15
Chemotaxis, xi, 50-1, 59, 61
Chemotherapy, x, 381
Cherbourg, breakwater at, xiv, 301;
wave power at, 300
Cherrapunji, Assam, rainfall at, i, 111-12
Cherries, drupes, xiii, 54;
origin and remarks, 224-5
Cherry Trees, xiii, 271-2;
lenticels on, 26
Chert, formation of, iii, 13
Chesapeake Bay, aerial fish patrol, i, 48;
drowned valley formation, xiv, 40, 255-6;
ducks of, xii, 257;
oysters of, 61;
ria coast, xiv, 257;
wave erosion in, iii, 56
Cheselden, William, x, 92, 123
Chest, diseases, studies of, x, 110, 112;
examination methods, 98-9, 108-9, 371, 373;
fixation of, 304-5
Chestnut Trees, family of, xiii, 193;
in American forests, xiv, 373
Chevrotains, xii, 313
Chewing, act of, ix, 82;
importance of, 227-8, 229, 230
Cheyne-Stokes Respiration, x, 340
Chiasmodus, xii, 24
Chicago, growth due to railways, xiv, 219;
level changes at, iii, 82;
sewage of, viii, 326;
terminals, electrification, vi, 162;
underground trolleys, vii, 12;
ventilation standards, viii, 332
Chicago Fire, dust from, i, 56
Chicago, Lake, iii, 148, 149
Chickadees, xii, 268

Chicken Cholera, inoculation for, x, 141-2, 208

Chicken Pox, immunity to, x, 207
Childbirth, among savages, xv, 278
Child Labor, factory system and, x, 244;
laws, remarks on, vii, 33
Children, adenoids in, ix, 224, x, 341-2;
artistic impulse in, xv, 296;
basal metabolism in, x, 271;
bones of, ix, 56, 57;
care in development of, 352;
care of, by state, xv, 290-1;
choice importance to, xi, 266-7;
clothes for, x, 308;
cold baths for young, 312;
convulsions in, ix, 133-4;
cretinism in, x, 349-50;
darkness effects on, 253;
dreams of, xi, 293;
ear troubles in, ix, 104;
education and environment importance, 344, 352;
exhaustion in, xi, 273;
foods for, ix, 33-4, 242, 295, x, 314-15;
grasping reflex, importance, xi, 43;
growth period, ix, 47-8;
habit acquisition, xi, 247, 249;
habit of evacuation in, ix, 252;
heart rate in, x, 334;
house-breaking, xi, 251-2;
imitation in, xv, 66-7;
language of, 142-3, 153;
malnutrition causes, ix, 228;
objection to sour tastes, 95;
relationships under polyandry, xv, 286, 294;
resemblance to parents (see Heredity);
savage attitude towards, 135, 195, 198;
skull growth in, 40;
soaps desirable for, x, 311;
suggestibility, xi, 307;
teeth, care of, ix, 228, x, 312-16;
transmission of nonhereditary characters to, ix, 343-4;
walking of, on what dependent, 351
Chile, Bolivia and, xiv, 306;
climate of, 358, 371;
coasts, 258, 265;
deserts of northern, xiii, 377;
nitrate fields, i, 34, 35, viii, 64, 72, 197, 280, xiv, 66;
temperate forests, xiii, 372
Chilled Iron, v, 241
Chilling, of body, x, 252-3, 306, 311;
effects, ix, 323
Chimborazo, Mount, formation, xiv, 225;
observatory site, ii, 149-50
Chimpanzees, xii, 383-4;
brain of, xv, 62 (fig.), 96;
expression of passion by, 65;
hand and foot in, 58-60;
mandible of, 94;
reasoning power in, 67-8;
skeleton compared to man's, 59

China, agriculture in north and south, xiv, 72-3;
ancient civilization, x, 13, xv, 123, 127;
beriberi in, ix, 35;
bubonic plague in, x, 165;
Cambrian deposits, iii, 184;
coal, in, 345;
coasts, xiv, 248, 251, 257;
corn growing, xiii, 212;
David's deer, xii, 316;
dust whirls, i, 60;
famines, xiv, 73;
fault-blocks of north, 125;
fishing with cormorants, xv, 223-4;
ginkgo tree, xiii, 315;
goral of, xii, 325;
gunpowder invention, v, 361;
hookworm in, x, 174;
influence on West, xiv, 357;
Jesuit survey, xvi, 123;
loess formations, i, 53-4, iii, 74, xiv, 63, 72-5;
medical education and Rockefeller Fund, x, 172;
medicine of ancient, 13;
meteorological service, i, 223;
mountain valley conditions, xv, 131;
opium and, xiii, 253;
plains and mountains, xiv, 217;
population distribution, 219;
rice-growing, xiii, 213, 214;
rivers of, xiv, 196;
shark's fins as food in, xii, 147;
smallpox inoculation in, x, 100, 207;
storm signals, i, 283;
sugar in, xiii, 215;
tea in, 227, 228;
temple orientation, ii, 26;
trees of, xiv, 377;
wheat in, xiii, 210
(see also Chinese)
China (pottery), viii, 283
China Clay, iii, 333
Chinch Bug, xii, 114
Chinchillas, xii, 289
Chinese, ancestor worship of, xv, 341;
ancient agriculture, xiii, 210;
ancient civilization, x, 13, xvi, 53, 54, 62;
ancient knowledge of cloves, xiii, 262;
ancient knowledge of lodestone, iv, 52, vi, 28;
calculating machines, xv, 183, xvi, 61;
finger nails of, xv, 260;
ideas of future life, 336;
ideas of eclipses, ii, 209;
in tropics, xiv, 356;
opium use, xiii, 253;
paper invention, v, 290;
prepotency in crosses, x, 230;
printing invention, v, 300-1, xv, 179;
use of feet by, 61;
veneration for writing among, 164;
well-water boiling, xiv, 140;
women, feet of, xv, 254-5, 260, 261 (fig.);
women, hairdressing of, 261
Chinese Astronomy, ii, 21-2, 331, xvi, 56-7
Chinese Language, xv, 170-1
Chinese Writing, xv, 169-72
Chinooks, i, 133, 369
Chipmunks, xii, 293-4
Chitin, xii, 39, 69
Chitons, xii, 58, 67
Chloramin, x, 181, 183
Chloramine T., x, 382
Chloride of Lime, viii, 333
Chlorides, halogen derivatives, viii, 210;
metal occurrence in, 130, 198
Chlorine, viii, 18, 22, 84-5, 181, 297-8;
as antiseptic, 333;
atomic weight and symbol, 383;
bleaching by, vii, 354, viii, 86, 146, 256, 274;
gold reaction with, 174;
in body tissues, 354;
in silicates, viii, 193;
manufacture and uses, 274, 284;
molecular speed, 24;
obtained from salt, 138, 140, 275;
plant uses, 337, 341;
solubility, in water, 111;
tests, for, 286, 287, 290;
use in chemical warfare, 262-3, x, 186;
water disinfection by, viii, 86, 274, 319, 321

Chlorine Derivatives, viii, 210, 211-12, 231
Chlorite, iii, 326-7
Chloroform, viii, 52, 212;
as anesthetic, x, 125

Chlorophyll, ix, 26, 27, xii, 11-12, 14, xiii, 79-80, 81, 84;
absent in saprophytes, 99, 100;
action in plants, viii, 335
Chocolate, calories in, ix, 299;
history and production, xiii, 233-5

Choice, power and importance, xi, 260-3, 265-7;
power of, in muscular responses, ix, 95, 121, 140

Choke Coils, vii, 17, 50

Cholera, discovery of germ of, x, 149, xvi, 184;
former ideas of, x, 286;
from water pollution, viii, 318;
germ of, x, 195;
immunity to, 207;
inoculation against, 208;
racial susceptibility to, xv, 50, 51
Choleric Temperament, xi, 153
Cholesterin, ix, 275
Chordates, xii, 127-9;
coelom in, 27
Chords, major and minor, xi, 106-8
Chorea, epidemic of, in Europe, x, 60;
rheumatism and, 224;
Sydenham on, 74
Christianity, Locke's "rational," xvi, 115;
Roman and medieval development, 99-100

Christian Science, attitude toward pain, xi, 116;
source of power, 306
Christmas Trees, electric lighting, vii, 342
Chromatic Aberration, ii, 99-100
Chromatin, ix, 41, 42, 44-7, 328
Chrome Yellow, viii, 162
Chromium, viii, 154;
affinity strength, 128;
alloys of, 273;
atomic weight and symbol, 383;
extraction from ores, 271;
specific gravity, 384;
test for, 287, 288-9;
use and occurrence, xiv, 238
Chromophor Group, viii, 258, 259
Chromosomes, ix, 46;
arrangement in pairs, 329, 330;
heredity controlled by, 328-41, x, 232-3;
human varieties, 233;
likeness in all cells, ix, 329;
number of, 46, 329, 339;
origin of energies, xvi, 145;
sex, ix, 339, x, 234, xvi, 156;
splitting of, in cell division, ix, 45 (fig.), 46-7, 332, 333

Chronic Diseases, wasting process of, x, 214
Chronometers, v, 65-7;
regulation to temperature changes, iv, 148
Chrysolite, iii, 334
Church, Prof. J. E., i, 118
Chyme, x, 325, 326
Cicadas, xii, 112
Cider, making of, viii, 249;
turning to vinegar, 218
Cigarette-smoking, dust particles from, i, 62
Cilia, of bronchial tubes, x, 202;
of simple animals, ix, 73-4

Cinchona, use of, in medicine, x, 154-5, xvi, 109

Cinchona Plantations, xiii, 251-2
Cincinnati, early growth, xiv, 219;
water supplies, viii, 318, 322
Cinder Cone, eruption, iii, 226
Cinder Cones, xiv, 100, 102
Cinematograph, in astronomy, i, 162, ii, 212
Cinnabar, iii, 327, 370
Cinnamon, xiii. 263-5

Circles, appearance of circumscribed, xi, 186;
divisions invented by Ptolemy, xvi, 94;
regarded as perfect curves, ii, 34, 49
Circuit Breakers, vi, 101-3, vii, 36, 37-48

Circuits, Electrical, kinds defined, vii, 364;
overloading of, vi, 9, 72;
primary and secondary, 9, 308;
proportioning of partial, iv, 300-1;
protection against overloaded, vii, 34-50
Circular Mils, iv, 282-3, 382
Circular Reflex, xi, 42;
in habit formation, 252-3

Circulation of Blood, ix, 195-200, 51 (diagram), x, 331, 337;
discovery, ix, 192, x, 61, 63-6, 69, xvi, 106-7;
discovery prepared by Vesalius, x, 51, 52;
efficiency, climatic effects on, x, 238-9;
former ideas of, 62-3, 65-6
Circumcision, among early Jews, x, 15;
untransmitted, 230
Circumzenithal Arc, i, 178, 180, 181, 369
Circues, iii, 66, xiv, 58
Cirro-Cumulus Clouds, i, 100, 103, 298
Cirro-Stratus Clouds, i, 99-100, 103, 179
Cirrus Clouds, i, 97, 99, 103, 179;
false, 102, 104, 372
Cirrus Haze, i, 100

Cities, aeroplanes to relieve congestion, i, 41-2;
climate, 333;
dependence on farms, vii, 221;
importance of lighting, vi, 279-80;
sewage disposal, viii, 324-9;
sites, favorable to, xiv, 219;
snow removal, i, 117, xiv, 140-1;
transportation facilities, vii, 198;
water supplies and purification, viii, 317-24;
white ways of, vii, 339-41
Citric Acid, viii, 222, 223;
formed by plants, 336;
solubility, 112
Citrus fruits, acids of, viii, 223
Civet (oil), xii, 353
Civets, xii, 351, 352-3, 354
Civilization, American, xv, 12, 131-2, 203;
arts and sciences in, iv, 9, 10;
climate and, xiv, 344, 357-62, xv, 31, 123-7, 383, xvi, 141;
clothing, shelter, and fire in, ix, 308-9, xv, 229;
conditions necessary to, 127-32;
development of, 3-4, 13-14, 28-31, 187-204;
dominant human impulses in, 185, 383;
earliest seats, xvi, 47;
evolution in, xv, 382, 383-4;
foresight and, 383;
geographic factors, xiv, 10, 31, xv, 122-3, 128-39;
government and,

380;
historic and prehistoric periods, xv, 167, 322;
influence of environment on, 122-39;
labor and, 125-6;
measured by timepieces, v, 57;
medicine and, x, 31;
moral laws and, xvi, 45, 47-8;
natural laws and, xv, 47-8, 382-3;
specialization in, 131-2, 203;
stages of, 187-204;
struggle to establish high associations, xi, 204;
transportation and, v, 18;
various machines and, 300
(see also Progress)
Civilized Races, facial angle in, xv, 45;
feet of, 60-1;
jaws in, 43;
monogamy of, 289, 290, 295;
natural selection in, 47-8

Civil War, Appalachian mountaineers in, xiv, 243;
captive balloons in, v, 225;
improvement of weapons in, 362, 380;
medical service in, x, 180;
scurvy in, 265;
Selfridge's periscope, v, 200;
Virginia weather, i, 308, 338;
western rivers in, xiv, 194
Clams, xii, 58-60, 66-7;
shells of, iii, 272
Clam Shell Cove, Staffa, xiv, 130
Clans, formation of, xv, 362-3
Clarinet, iv, 234
Clark, Alvan, telescopes, ii, 106, 109, 143
Clarksburg, W. Va., deep well at, iii, 120
Clausius, xvi, 135
Clavichord, xv, 318
Claw Hammers, v, 25

Clay, composition and properties, viii, 90, 282;
composition, origin and uses, iii, 25, 372-3;
elasticity of, iv, 36;
imperviousness to water, xiv, 137;
in soils, iii, 27-8;
red, on sea bottom, 54;
residue of primary rock, viii, 195;
rock formed from, iii, 13 (see Shale)
Clay Worm, xii, 54
Cleanliness, bathing for, ix, 313;
health and, x, 311;
in war against tuberculosis, 290;
ventilation factor, ix, 270
Cleansing, action of soap in, viii, 141-2;
chemicals used in, 135, 141, 146, 147, 208-9
Cleavage, of crystals, iii, 318, viii, 202;
of various minerals, iii, 321-41
Cleistogamous Flowers, xiii, 120
Clematis, as index plant, i, 255;
family of, xiii, 196
"Clermont," steamboat, v, 192, 377

Cleveland, Ohio, water supply system, v, 260-1;
water supplies and typhoid rate, viii, 322

Cliffs, formed by faulting, iii, 87-8, xiv, 38;
in inclined strata, xiv, 84-5, 88;
loess, iii, 74;
of jointed rocks, xiv, 133;
sea, 251;
undercut by wind, iii, 73
Climate, Climates, i, 197-211;
altitude effects, xiv, 220, 223;
carbon dioxide effects, viii, 49;
changes of, i, 199-202, xiv, 29-30, 360-2, xv, 72, 73, 74;
changes affecting drainage systems, xiv, 188;
changes, artificial, i, 345;
changes, extinction of races by, xv, 99;
changes in relation to plant distribution, xiii, 320, 321;
civilization, and, xiv, 344, 357-62, xv, 123-7, 383;
classification, i, 208;
data and statistics, 202-8, 214;
definitions, 199;
determining elements of, xiv, 344-56;
earth's internal heat and, 13;
effects, historical and biological, xvi, 141-2;
forest and prairie types, xiii, 348-9;
forest effects on, xiv, 379;
Gulf Stream effects, viii, 37;
hot, unhealthfulness of, x, 251;
human effects of, i, 316, 323-4, 327, 331;
human efficiency and, xiv, 357;
of past ages, iii, 172-4, 178, 184-5, 202, 203, 204, 220, 241, 246-8, xiii, 307-8, xv, 72, 73, 74, 76;
of plateaus, xiv, 222-4;
plant societies determined by, xiii, 381-2;
rugged, effects on circulation, x, 238-9;
therapeutic value of, 383;
topographical effects of, xiv, 41-2, 51-2, 124;
vegetation determined by, 363-79, 380-1;
zones of, (see Zones)
Climatic Charts, i, 206-8, 212-13
Climatography, i, 208, 369
Climatology, in therapeutics, x, 383;
present state, i, 211, 369
Climbing Plants, xiii, 27, 65;
in tropical forests, xiv, 368
Climographs, i, 324, 369
Clinton Iron Deposits, iii, 358
Clione, xii, 19
Clippers, old Atlantic, v, 188
Clocks, balance wheels of, v, 68;
Chaldean, xvi, 58;
electric regulation, v, 74;
first conceived in cathedral, 109;
historical development, 58-65;
Jerome's standardized, 50-1;
pendulum escapement, 73-4
Closed Circuits, defined, vii, 364
Cloth, making of, v, 268-83
(see also Weaving)

Clothes, Clothing, body heat regulation by, v, 348, ix, 308-9, 311-12;
civilization in relation to, ix, 308-9;
colds in relation to, x, 240, 253;
"habit" in, xi, 247;
hygiene of, x, 306-10;
infants, ix, 351-2;
origin and purposes of, x, 306, xv, 252-5;
primitive, v, 14, xv, 256-7;
touch sensations of, ix, 92;
warmth dependent on air insulation, iv, 178;
working, xi, 279, 362
Clothes-driers, centrifugal, iv, 73
Clotting of Blood, ix, 180, 189
Cloud Banners, i, 104-5, 369
Cloudberry, spread, xiii, 342
Cloudbursts, i, 109, 110, 111, 369, vii, 218;
destruction effected by, xiv, 41
Cloud Caps, i, 104-5, 369
Cloudiness, measurement, i, 85
Clouds, i, 90-105;
aviation in, 300-2;
Brocken specters in, 185;
earth heat retention by, iv, 183, 184;
electrical discharges, vii, 18, 207-10, 213;
electrification, i, 150, 151, vii, 206, 207, 217;
electrification of earth by, iv, 269, 270;
formation and kinds, i, 90-105;
formation, cause of rapid, viii, 304;
formed by forest fires, i, 333;
heights, 17-18, 103-4;
light diffraction by, 183, 185;
noctilucent, 17-18, 58, 377;
none in stratosphere, 20;
observation at weather stations, 85-6;
paintings of, 105;
pictures, where obtainable, 103;
self-luminous, 149;
snow and rain without, 119;
thunderstorm, vii, 217
Clouet, steel experiment, xvi, 174
Cloven-footed Animals, xii, 310
Clover, fertilization, xiii, 138;
nitrogen fixation, by, viii, 74, xiv, 66;
sleeping of leaves, xiii, 113
Clover Seed, method of gathering, v, 240
Cloves, Clove Trees, xiii, 262-3

Club Mosses, fixity and variation, xiii, 326, 327;
history, 305-6, 307, 314, 317, 323;
number of species, 323;
present and former species, iii, 254, xiii, 306, 308

Clutches, automobile, vii, 143;
electromagnetic, vi, 104
Cnidus, School, of, x, 22-3
Coagulation, by cooking, viii, 368;
of colloids, 315;
of proteins, 352
Coal, "Blue," v, 174;
carbon dioxide from, amount, i, 13;
conversion to electric power, vi, 216;
deposits in mountains, xiv, 237;
deposits in U. S., iii, 345-8;
excavating by machine, v, 262;
formation, iii, 198-201, 253-4, 343-5, viii, 44-5, xiii, 10, 68, 311-13;
handling in power plants, v, 353-4, 357;
heat measurement, viii, 360-1;
heat value, iv, 193;
importance, iii, 343, 345-8;
kinds, 344;
not a mineral, 307;
Permian deposits, 204;
specific gravity of, iv, 112;
supply, use, and waste, iii, 346, v, 171-2, vi, 352, viii, 283;
water power and, xiv, 191;
"white," v, 76;
work value, how estimated, iv, 189-90, 193-4
Coal Age, iii, 202;
insects of 279;
landscape of, 272 (Pl. 15);
length and antiquity, xiii, 314;
plants, iii, 253-4, xiii, 307-11, 315-16
(see also Pennsylvanian Period)
Coal Dust, as engine fuel, v, 156, 212;
explosions, i, 63
Coal Gas, in balloons, v, 223;
liquefaction of, iv, 171
Coal Gas Engines, v, 155
Coal Mines, compressed air uses, i, 26
(see also Mines)
Coal Series, iii, 344-5;
carbonization in, viii, 44

Coal Tar, production and products, viii, 252-4;
saving of, 47

Coal Tar Hydrocarbons, as motor fuels, viii, 209

Coastal Plains, xiv, 213-14, 215

Coast Range Mountains, geology of, iii, 89, 94-6, 130, 224, xiv, 127-8, 229

Coast Range Revolution, iii, 224
Coasts, xiv, 246-71;
Atlantic and Pacific types, 247-50;
compound, 254, 264;
cycles of development, 254-5;
economic importance, 264-5;
emerged, iii, 56-7, xiv, 253, 262-3;
hanging valleys on, 57-8;
historical effects of, 249-50;
neutral, 248, 254, 263-4;
photographic mapping, i, 47-8;
regular and irregular, iii, 56-7, xiv, 250-3, 255;
submerged, iii, 57, xiv, 253, 255-62;
wave destruction of, iii, 55-8, xiv, 44-7, 216, 301-3

Coatzacoalcos, harbor of, xiv, 266
Cobalt, viii, 154;
affinity strength, 128;
atomic weight and symbol, 383;
classification place, 178, 183;
magnetic susceptibility, iv, 251;
ores, viii, 198, 270;
specific gravity, 384;
test for, 287, 289
Coblenz, Roman name, xiv, 89
Cobras, xii, 226-9;
mongooses and, 352
Cocaine, an alkaloid, viii, 240;
history and uses, xiii, 254-5;
taste sensations reduced by, xi, 72
Cocci, (bacteria), x, 195
Cochineal, source, xii, 112
Cockatoos, xii, 266;
Arara, v, 9-10
Cocklebur, xiii, 57 (fig.), 343
Cockroaches, xii, 107;
ancient, iii, 279, xii, 104
Cocoa, xiii, 235;
American origin, xiv, 382;
source, 383;
polyuria induced by, x, 344
Cocoa Butter, viii, 246
Coco de Mer, xiii, 60, 154
Coconino Forest, xiv, 373-4, 378
Coconut Oil, ix, 28, xv, 125
Coconut Palm, xiii, 219-20, 244, xv, 125;
chatties, intoxication from, xii, 371;
on coral islands, 42;
fossil found in France, xiii, 319;
seed dispersal by, 59, 346

Coconuts, character, uses, and production, xiii, 219-20;
double, of Seychelles Islands, 60;
gathering of, by monkeys, xii, 378;
source and uses, xv, 125;
unaffected by sea water, xii, 42
Cocoons, xii, 118
Coction, x, 21, 40
Cod (fish), xii, 163-4;
eggs of, 141
Cod Liver Oil, vitamines in, x, 261
Coefficient of Expansion, iv, 145, vi, 265

Coelenterates, iii, 259, 266-7, xii, 26, 33-43

Coelom, xii, 27, 48

Coeur d'Alene Mining District, iii, 362-3, 368

Coffee, history and production, xiii, 231-3;
insomnia from drinking of, ix, 219;
polyuria induced by, 274-5, x, 344
Cog Wheels, v, 29;
screw and, iv, 92, 93 (fig.)
Coils, electromagnetic, vi, 92, 93, 98-9;
form-wound, 202, 223;
induction, vii, 364;
primary and secondary, iv, 304, 383, vi, 308, vii, 364;
resistance, 364
Coins, chemical analysis of, viii, 286, 291;
copper alloys in, 164, 171;
gold and silver, making of, iv, 150
Coke, discovery, v, 315-16;
manufacture and use, viii, 46-7, 252
Col (meteorology), i, 238, 369
Cold, body regulation to, x, 250;
clothing as protection against, 306;
comparative degree of, v, 345;
physiological effects of, ix, 37, 78-9, 319-20, x, 239, 252-3, 271;

"production" of, v, 345-7;
sensation of, ix, 93-4, 319-21, xi, 109, 112-13, 114;
skin defense against, 113

Cold Air Machines, v, 352-3

Cold Baths, ix, 313, 321-2, x, 240, 253, 312, 383

Cold-Blooded Animals, ix, 305;
diseases of, x, 206;
heart of, ix, 84;
temperature changes and, 78-9, 306-7, x, 250
Colds, air during epidemics of, viii, 332;
catching of, ix, 322-3, x, 239, 252-3, 306;
diseases from, 253;
ears affected by, ix, 103;
from uncleanliness, x, 311;
head, 341;
infectiousness, i, 326;
susceptibility of men and women to, x, 240;
taste sensations in, xi, 73
Cold Storage, iv, 187-8, viii, 371;
effect on vitamines, x, 263;
electrical, vii, 229-30
(see also Refrigeration)
Cold Sweat, xi, 131, 132
Cold Waves, i, 370;
prediction of, 239
Coleus, xiii, 42, 79, 205
Collectors, electrical, i, 144, 370
Collection Stage, xv, 187, 188-91
College Students, study habits, xi, 212, 289
Collodion, making of, viii, 255
Colloids, viii, 314-16, 375;
origin of life from, xii, 11-12;
relation of water to, viii, 355-6
Colonnaded Spectrum, ii, 115

Color—Colors, chemistry of, viii, 85-6, 258, 259, 312;
complementary, iv, 366-7, xi, 91-4;
contrast, ix, 95;
determined by vibration rate, 114, 115;
distance effects, xi, 182;
flame, viii, 301;
heat absorption by, x, 309;
hue, tint, and saturation, xi, 90;
illusions of, in different lights, iv, 323, 324, 370, 379-80;
induction of, xi, 94-5;
in interior decoration, vi, 273, 274-5;
memory, xi, 220-1;
mineral identification by, viii, 201-2;
mixtures, iv, 369, xi, 92-3;
neutralization, 91-3;
of glass, viii, 282;
of objects, iv, 364, xvi, 119;
of pigments, iv, 369-70;
perception and sensation of, 360-1, 364-5, 366, vi, 282, ix, 114-17, xi, 89-90, 91-2, 95-6;
physical effects, 63, 96;
primary, iv, 366, xi, 90;
psychological effects, vi, 273, 274-5;
racial classification by, xv, 32-34, 36-7;
rainbow, i, 175, ix, 115;
spectrum, iv, 357-9;
sunrise and sunset, i, 166, 167-8;
temperatures for different, iv, 361;
wave lengths of, 359, 360, 365, xi, 90;
white light, (see White Light)
Colorado, arid topography of, xiv, 42;
glaciers of, 54;
Jurassic strata of, xii, 165;
mining products, iii, 362, 363, 364, 366
Colorado Plateau, iii, 140, 229-30
Colorado River, navigability, xiv, 195;
Salton Sink and, iii, 156-7, xiv, 205;
superimposed character, 173;
water supply of, 182
(see also Grand Canyon of the Colorado)
Color Blindness, ix, 116, xi, 93;
inheritance of, ix, 340-1, x, 234;
in men and women, ix, 340-1
Colored Hearing, xi, 222
Color-Index of Stars, ii, 297-8
Color Photography, iv, 368-9
Color Printing, iv, 370-1;
in newspapers, v, 304
Color Vision, iv, 364-5;
inheritance of, ix, 340;
limits of, iv, 360-1;
theory of, x, 96
(see also Colors)
Colt Gun, v, 363-4

Columbia Plateau, iii, 105, 181, 227-8, xiv, 104, 164, 170, 172, 188

Columbia River, xiv, 174-5;
canyon of, iii, 39, 226, 228, xiv, 165-6;
navigability, 195;
salmon of, xii, 157
Columbine, fertilization, xiii, 126-8;
flowers, 196

Columbium, atomic weight and symbol, viii, 383

Columbus, compass troubles of, iv, 52-3, vi, 27;
debt to early scientists, ii, 12, 13, 40;
discovery of America, xiv, 309;
Genoese birth, 310;
in Sargasso Sea, xiii, 73;
on rubber balls in Haiti, 245;
potatoes found by, 218, 219;
syphilis introduced by sailors of, x, 60;
tobacco-using seen by, xiii, 256;
trade winds on voyage, i, 128-9
Columnar Structure, iii, 111, 212
Combustion, iv, 138;
chemistry of, viii, 11-13, 53-63, 100;
heat of, 308;
oxygen and, i, 10;
oxygen and, viii, 35-6, 61;
power developed by, ix, 15-16
Comets, ii, 273-82;
asteroids and, 258;
dangers to earth, 279-80;
disintegration, 286-7, 288;
families related to planets, 270-1;
first scientific studies, 40, 41, 57;
former ideas, 83-4, 85;
habitability, ii, 250-1;
in relation to solar system, 164;
Newton's views, 85;
orbits discovered, 85;
orbits and meteor streams, 287;
photographic study, 134;
Seneca on, 85;
solar corona and, 224;
various particular, 280-1, 286
(see also Halley's Comet)
Commensalism, xii, 32
Commerce, ocean, development of, xiv, 305-11
Commercial Meteorology, i, 261-70

Common Salt, composition and properties, iii, 332, vi, 109-10, 111, viii, 84;
deposits, iii, 332, 374-5, viii, 139-40, 196, xiv, 141;
deposits from atmosphere, i, 59-60;
in body fluids, ix, 174, 175;
in diet, x, 256;
in ground water, xiv, 142;
in protoplasm, ix, 32;
in sea and inland waters, iii, 51-2, 152-3, 154-5, 332, 374, viii, 138-9, 195-6, xiv, 206, 295-7;
mixture with ice, temperature resulting, iv, 175;
physical and chemical divisions, 21;
plants and, xiv, 364;
production, iii, 374, 375, viii, 140, 275;
refining of, for table, xiv, 296;
size of molecules, vi, 112;
taste of, xi, 70, 71, 72;
uses, iii, 332, viii, 138, 140, 276-7
(see also Sodium Chloride)

Commutators, electrical, iv, 308, vi, 159, 177-9, 344-5;
use and construction, vii, 364-5
Como, Lake, iii, 146
Comparisons, measuring by, vii, 341
(see also Contrasts)

Compass, (Gyroscopic), iv, 254-5, v, 201, 340, 384

Compass (Magnetic), vii, 365;
compensation on iron ships, iv, 254, v, 340, vi, 42;
development, xvi, 102;
deviation, defined, iv, 247, vi, 42;
disturbances accompanying aurora, i, 161;
electric current effects, vi, 20, 88;
invention, 29;
magnet effects, 27, 32, 42-3;
modern improvements, 41-2;
needle, pointing and declination of, iv, 246-7,

(see also Magnetic Needle);
sun disturbances, vi, 40;
variation, defined, iv, 247;
variations on voyage of Columbus, 52-3, vi, 27

(see also Mariner's Compass)
Compensators, electrical, vi, 253-5
"Complete Recall," xi, 378
Complexes, mental, x, 355-6;
in hysteria, 361, 362
Composing Machines (see Linotype, Monotype)
Composition of Forces, iv, 75-7
Compostella, Spain, shrine at, xii, 65
Compounds, Chemical, viii, 16, 100, 375;
analysis of, 285-95;
colors of, 312;
combustion of, 61;
constancy, 110, xvi, 160;
contrasted with mixtures, viii, 15;
decomposition, 101-2;
electrical balance, 121;
formation types, 20, 100;
formulæ, 91;
metallic, 130, 146;
molecular weights, 92;
multiple proportions law, 110;
nomenclature, 97-8;
organic (see Organic Compounds);
substitution in, 102;
unstable, 66;
with water, 20, 38-9
Compound-Wound Dynamos, vi, 187, 188-9, 191-2
Compound-Wound Motors, vi, 233-5
Comprehensive Terms, xi, 191

Compressed Air, applications and uses, i, 25-6, 27-9, iv, 30-2, 106, 129-31, v, 111-38;
discovery, 109-11;
expansion effects, cooling by, iv, 191, v, 128-9, 351-3, xiv, 14;
heat of, v, 126-8, 161, 351;
methods of compression, 89-93, 126-7, 174;
physiological effects, i, 329, iv, 31-2, v, 119-21;
pressures used, i, 27

Compressed Air Locomotives, i, 26, 27, iv, 129, v, 133

Compression, heat of, i, 90, v, 126-8, 161, 351

Compressors, Air, v, 89-93, 127, 351
Compte, on sciences, x, 368
Comstock Mines, Nevada, iii, 366, 368;
temperature in, 121
Concentration, chemical, viii, 310-11;
mental, xi, 235-6, 378-9
Conchs, xii, 72-3, 73-4
Concordant Coasts, xiv, 248, 249

Concrete Buildings, value in earthquakes, xiv, 343

Concrete Dams, expansion joints, v, 71
Concrete Sciences, xvi, 42
Concrete Ships, v, 194-5
Concubinage, xv, 289, 290
Condensed Milk, scurvy from, x, 266

Condensers, electrical, iv, 265-7, vi, 170-4, 301-5, vii, 365;
applications, vi, 285-6;
capacity of, iv, 267-8;
dielectric, vii, 366 (see Dielectric);
discharge methods, iv, 267, vii, 366;
in automobiles, vii, 138-9;
oscillating currents, 373-4;
plate, vi, 170, 293-4, 295;
purpose, vii, 363;
synchronous, vi, 262;
use in wireless communication, iv, 314, vii, 263, 264, 266, 267

Condensers, Steam, v, 145, vi, 354-6
Condiments, as foods, viii, 362, 366;
effects on stomach, ix, 243-4;
sources, xiii, 265
Conditioned Reflex, xi, 198-201, 204;
in advertising, 348;
in habit formation, 251-2;
in hypnotism, 321-2
Condors, xii, 260
Conduct, rules of, how enforced, xv, 374-5
Conduction, of heat, iv, 138, 177, 178-9

Conductors (electrical), iv, 259, vi, 77, 294;
acids and bases as, viii, 122, 123;
air, i, 144-5;
copper, viii, 164;
discovery, vi, 13;
for radio currents, vii, 296;
resistance of, iv, 281-2 (see Resistance);
tabular information, vii, 377-84;
temperature effects on, iv, 301;
various materials as, 283
Conductors, (heat), iv, 176, 177, 179
Conduit Wiring Systems, vii, 55-60, 365
Condyle, xii, 239

Confectionery, poppy seed used in, xiii, 250, 254;
pure food law on, viii, 370-1
Confidence, psychological effects, xi, 212-13
Conglomerate, iii, 13, 377;
sedimentary rock, xiv, 18

Congo River, connections with Nile sources, xiv, 186-7;
furrow of, 287;
ocean slope at mouth of, 24;
varied course, 155
Congo River Basin, hippopotamus of, xii, 310;
okapi of, 321
Congo Tribes, habits of, xv, 225, 370
Conies, xii, 288, 304
Conifers, xiii, 174, 178;
American forests of, xiv, 371, 372, 374;
ancestors of modern, xiii, 310;
first appearance, iii, 256;
number of species, xiii, 323;
transitional form, 318
(see also Gymnosperms)
Conjugated Proteins, viii, 352
Connecticut, drainage studies, xiv, 131;
oyster industry, xii, 61
Connecticut River, course, iii, 234;
preglacial valley, xiv, 60

Connecticut Valley, down warping of, iii, 210;
igneous rock formations, xiv, 107, 111;
lava deposits, iii, 212;
origin, 232;
rocks under, 213 (fig.);
tracks of extinct animals in, 16, 291;
volcanic action in, xiv, 318

Connecting Nerve Cells, ix, 127, 128 (fig.), 129, 130;
of brain, 148-9, 150-1
(see also Connector Neurones)
Connective Tissue, ix, 13, 58-9;
growth of, 287;
in muscles, 75, 79;
ligaments formed of, 71;
making of, 54;
scars formed by, 48, 287
Connective Tissue Skeleton, ix, 71-2
Connector Neurones, xi, 21;
in brain, 31-2, 200;
in spinal cord, 26;
development in embryo, 35
(see also Connecting Nerve Cells)
Conscious Life, parts concerned in, ix, 21-2
Consciousness, in mental life, xi, 47;
habit and, 253-5;
motor response and, 27-8, 123-4, 202;
psychology as science of, 10-11;
"stream" of, 193
Consequent Streams, xiv, 157, 174
Conservation, technical meaning, iv, 382
Conservation of Energy, iv, 40-1, vi, 128;
establishment of doctrine, xvi, 131;
remarks on doctrine, iv, 9

Conservation of Resources, coal, v, 172, viii, 283;
forest, vi, 366, xiii, 9, 371-2, xiv, 382;
petroleum supply, vii, 309;
soil, xiv, 64
Constantinesco, George, v, 107-8
Constantin Metal, vi, 77

Constipation, causes and treatment, ix, 250-2;
chronic, x, 316-17, 328-9;
hyperacidity caused by, 322
Contact Catalysis, viii, 82-3, 103, 316
Contact Senses, ix, 86, 91-5;
connections with brain, 142
Contempt, sentiment of, xi, 148

Continental Climates, i, 208, 370, xiv, 346, 347

Continental Islands, xiv, 271-6, 278-81

Continental Platforms, major relief features, xiv, 9, 27;
margins and slopes, 25, 287-8
Continental Rivers, xiv, 153
Continental Shelves, iii, 52, xiv, 287;
area covered by, iii, 52, xiv, 26;
breadth of, 25, 285;
cutting of, by waves, iii, 55-6, xiv, 46-7;
deposits on, iii, 53, xiv, 284-5
Continental Slope, xiv, 287-8;
deposits on, iii, 53
Continents, average elevation of, xiv, 26-7;
climate on opposite sides, 346;
distinction from islands, 23;
drainage systems,
190;
former connections, xiii, 320, xiv, 290;
former submergence, iii, 216, xiv, 19-20;
present, never covered by deep sea, iii, 55;
rate of wearing away, xiv, 41;
tides modified by, 292
Continuity, of action, xi, 264-5;
of training, 257
Contrast, association by, xi, 197;
attention aroused by, 344;
effect on tastes, 72;
illusions of, 189
Convection, iv, 139, 178-9, 185

Converters, electrical, vi, 162, 332-48, vii, 365;
speed-limiting devices, 48;
in traction systems, 199, 365
Convolutions of Brain, xv, 62, 63, xi, 29
Convulsions, production of, ix, 133-4
Cook, Capt. James, xvi, 123;
story of Polynesian, xv, 124
Cooke, Dr. R. P., x, 161
Cooking, chemistry of, viii, 367-9;
development of art of, xv, 13, 195, 232-3;
effect on vitamines, ix, 36, x, 263, 266;
frying habit, ix, 286;
good, advantages to digestion, 241-2;
"pressure cookers," iv, 171;
use and advantages, xv, 229
Cooking (electric), vii, 89;
special rates for, 174;
in U. S. Navy, 332-3
Cooking Utensils, aluminum, viii, 155;
copper, 164
Coolidge Tube, x, 185

Cooling, contraction by, iv, 134-5, viii, 107-8;
dynamic, i, 90
(see also Expansion, cooling by);
use of water in, viii, 37;
water changes in, iv, 149, 150-1, viii, 38
(see also Refrigeration)
Coon Bear, xii, 338
Cooper, Astley, x, 129-30
Coordinates, iv, 16
Copal, in varnishes, viii, 265
Copepods, xii, 18, 84
Copernican Theory, ii, 43-4;
aided by Pythagorean teachings, xvi, 82;
establishment of, iv, 95;
Galileo and, ii, 54, 56;
Kepler, and, 49;
not accepted at once, 45, 46, 60, 311
Copernicus, ii, 42-4, iv, 19, xvi, 102;
as astrologer, ii, 21;
"De Revolutionibus," 12, 43;
ideas of motion, 63;
on speed and orbits of planets, 49;
studies in Italy, 12
Copper, affinity intensity, viii, 128, 164;
alloys, 164, 171, 273;
atomic weight and symbol, 383;
density of, iv, 113;
electrical conductivity, iv, 283, vi, 77, 79, 80, viii, 164;
electrical positiveness, vi, 59;
electric welding of, iv, 312;
electrochemical analysis, viii, 295;
extraction methods, 270-1;
fungicide uses, 170;
formerly mined in New Jersey, xiv, 112;
heat conductivity, iv, 176, 179;
melting point and requirements, 162, viii, 384;
name, origin of, xv, 157;
native, iii, 327;
occurrence and production, 360-2, viii, 129, 130-1, 163, 198, xiv, 237, 288;
refining of, vii, 319-20, viii, 166-7, 272;
specific heat of, iv, 155;
specific gravity, viii, 384;
tests for, 286, 287, 288;
uses, iii, 359-60, viii, 126-7, 163-4, 167;
valences of, 94, 189
Copper Bromide, color, viii, 123
Copper Chloride, color, viii, 123;
electrolysis of, 124
Copperhead Snakes, xii, 233

Copper-Plating, vii, 314-15, 317-18, viii, 165-6

Copper Pyrites, iii, 326

Copper Smelting, smoke precipitation, vii, 347

Copper Sulphate, color, viii, 123;
electrolysis of, 125;
uses, 146, 332;
used in Egyptian medicine, x, 12;
water and, mixture of, iv, 131

Copper Wire, for electrical transmission, vi, 77, 79, 80, vii, 20, 22-3, 104;
standard tables, 378-80;
table of carrying capacities, 381
Copra, xiii, 220, xv, 125
Coquina Rock, viii, 152
Coral Reefs, xii, 40-2, xiv, 263-4;
formed in shallow water, iii, 53, xiv, 276;
oceanic islands built of, 276, 277;
temperature limitations, 263-4, 305, xii, 40
Corals, iii, 259, 266, 267-8, xii, 38-43;
calcium carbonate in, viii, 151;
false, xii, 47
Coral Snakes, xii, 213, 225-6
Corbeil, Gilles de, x, 37
Corcovado Peak, xiv, 112
Cordage, sources, xiii, 238-41
Cordaitales, xiii, 310, 317
Cordaites, iii, 255, 256
Cordova, university of, xvi, 100
Cores, in electric machines, vii, 365
Cork, specific gravity of, iv, 109, 112
Cormorants, xii, 253;
fish-catching with, xv, 223-4

Corn, American origin, xiii, 182, 211, 212, 221, 222;
economic importance, 208;
food value, viii, 364, 365, x, 262, 278, 279;
grains of, fruits, xiii, 56;
in grass family, 179;
leaves of, 32, 176;
monocotyledon, 178;
stalks, glucose from, ix, 230;
stalk structure, xiii, 26;
starch manufacture from, viii, 243;
time to plant, i, 255;
tryptophane in, viii, 351;
weather best for, i, 245-8
(see also Indian Corn)
Corn Crakes, xii, 262

Cornea, of eye, ix, 109, 110 (fig.), xi, 84, 85;
astigmatism of, ix, 113-14;
no warm spots in, xi, 112
Cornets, iv, 231
Corn Flour, vitamines in, x, 267
Corn-Harvesting Machines, v, 249
Corn Syrup, as food, ix, 292;
vitamines in, x, 262
Corolla, xiii, 45;
absent in some plants, 46, 182;
evolution of, 201

Corona Discharge (electricity), vii, 10-11, 23

Corona of Sun, ii, 219-26, 184;
appearance in eclipses, 213-14;
comets and, 281;
photographic studies, 128, 129;
rotation, 121;
study of, proposed method, 225-6;
study in various eclipses, 211-12, 214, 218
Coronas, atmospheric, i, 183-4, 370
Coronium, discovery, ii, 211, 223
Corposants, i, 157-8
Corrasion, defined, iii, 29;
by ice, 63-4;
by sand, 72;
in Grand Canyon, 40;
potholes formed by, 39-40
Correlation, mathematical, i, 253
Correlation of Energy, iv, 40
Corries, of Scotland, xiv, 58
Corrigan, John, x, 112
Corrosion, chemical, viii, 10, 13, 100;
Electrolytic (see Electrolytic Corrosion)
Corrosive Sublimate, viii, 170
Cort, Henry, v, 316
Corti, Organ of, xi, 102
Corundum, iii, 327-8
Corvisart, x, 110
Corymb, flower-form, xiii, 50
Coryza, x, 295, 341
Cos, School of, x, 21-2;
influence in middle ages, 37
Cosmogony, defined, ii, 362;
theories, ancient and modern, 366-84, xvi, 58, 76-9, 80, 81-2, 84

Cossacks, bows and arrows of, xv, 214

Cotopaxi, Mount, xiv, 225

Cotton, as clothing material, ix, 311, x, 307, 308, 309;
cultivation, xiii, 238;
dyes for, viii, 259;
fiber, 229, 254, ix, 30, xiii, 237;
fiber to fabric, v, 269-83;
humidity effects, i, 78;
importance, xiii, 208, 235, 236;
kinds, v, 269, xiii, 236;
Mediterranean origin, xxiv, 382;
mercerized, viii, 255;
preparation for manufacture, xiii, 237-8;
removal of, from wool, viii, 255;
vegetable silk from, 255-6
Cotton Cloth, making of, v, 269-83
Cotton Crop, forecasts, i, 251
Cotton Gin, Macarthy's, xiii, 238;
Whitney's v, 269-71, 376
Cotton Plant, xiii, 236-7
Cotton Seed, uses, xiii, 238
Cottonseed Oil, viii, 246;
solidified, 232, 247
Cottrell, Dr., vii, 216
Cotyledons, xiii, 60;
classification by, 176
Cougars, xii, 363
Coughing, reflex action, ix, 135, 258, xi, 20

Coulomb, electric quantity unit, iv, 280, 284, vi, 17, 69, 82, vii, 365, 374

Coulomb, C. A., electrical work, vi, 17-18, xvi, 122;
quantity unit named for, iv, 280
Countertrade Winds, i, 130, 366
Counter Voltage, vii, 365;
in motors, vi, 226-8, 232, 233, 236
Counting (see Numbers)

Country Rock, definition and character, xiv, 105

Courage, motor origin, xi, 61
Courtship, among animals and birds, xv, 274-5
Cows, domesticating qualities, xv, 197;
fat production by, ix, 298;
milking by electricity, vii, 222, 226-7
Cow's Milk, for infants, ix, 33-4, 346
Cowries, xii, 73
Coyote, xii, 340
Crabs, iii, 260, 276, 279, xii, 85-7;
deep sea, 23;
hard and soft-shelled, 83;
"no-body," 89;
sponges and, 32
Cramps, from cold baths, ix, 313;
significance, xi, 120
Cranberry, bogs, xiii, 382;
origin, 225;
ovary, 202
Cranes, (birds), xii, 262
Cranes, hydraulic, v, 101-2, 106

Cranial Nerves, ix, 131, 132, 142, xi, 29-31, 76;
doggerel verse on, 214
Crater Lakes, iii, 155, xiv, 101, 203
Craters, formation of, xiv, 101-2;
of Hawaiian volcanoes, iii, 104, 105, xiv, 322;
of Mount Katmai, iii, 101, (fig.)

Crawfish, xii, 87

Creation, ancient conceptions, ii, 366, xvi, 77

Creative Imagination, xi, 225-7
Creepers (birds), xii, 268
Creeping Speedwell, xiii, 28
Creodonts, xii, 332, 339, 366, 375
Creosote, constituents, viii, 333;
source, xiii, 255
Crepuscular Rays, i, 169, 370
Cress, xiii, 197, 222
Cresylic Acid, viii, 238, 253, 333
Cretaceous Peneplain, iii, 232
Cretaceous Period, iii, 214-20;
animals and plants of, 20, 256-7, 266, 295-6, 292, 297, xii, 154, 202, 210, 242-3, 275;
first mammals in, xv, 71
Crete, ancient meteor in, ii, 284;
early civilization of, xiv, 281;
elevation changes, 33;
Phaestos disk, xv, 176 (fig.)
Cretinism, x, 350
Crevasses, formation, iii, 63;
cirques from, 66
Crex Rugs, xiii, 188, 236
Cribo, (snake), xii, 219
Crickets, xii, 110

Crile, Dr. George W., on emotion effects, xi, 135-6;
on fear in animals, 136;
on kinetic system, 57-60;
on laughter, 355, 356;
on pain, 119, 120;
on suppressed desires, 141-2
Crime, hypnosis and, xi, 320;
of crowds, 329-31;
punishment of, among primitive peoples, xv, 369-75, 379-80;
street lighting and, vi, 279
Crinoids, xii, 23, 49
Cripple Creek Gold District, iii, 367

Crisis, in diseases, Hippocratic doctrine, x, 21

Critical Period, of crops, i, 248-50, 370

Critical Pressure, iv, 171-3

Critical Temperatures, i, 29, iv, 171-2, viii, 303-4;
of various substances, iv, 173
Crocker Land, i, 173
Crocodiles, xii, 182, 196, 198-202;
resemblance to tuatera, 184;
sleeping sickness due to, x, 169;
ziczacs and, xii, 263
Cro-Magnons, xv, 99-102, xvi, 50;
art of, xv, 110-21;
implements of, 109
Crompton, mule-spinner of, v, 274, 376
Cromwell, sea captain, v, 305

Crookes, Sir William, cathode ray studies, x, 184, xvi, 165, 193;
on nitrogen needs, i, 34;
theory of fourth state of matter, iv, 54-5, xvi, 193;
vacuum tubes named for, iv, 317
Crookes Tube, iv, 317, vi, 114, vii, 251;
electron study in, xvi, 193;
fluorescence in, iv, 380;
phenomena of, 50;
X-ray discovery and uses, x, 184, 185
Crop Forecasts, i, 250-2
Crops, critical period, i, 248-50, 370;
rotation of, viii, 342-6;
sun spots and, ii, 186;
weather and, i, 245-50, 252-3
Crossbows, xv, 215

Crosses, inheritance of characters in, ix, 333-7, x, 231-2, xiii, 332

Crossfell, helm and bar of, i, 105, 374

Cross Fertilization (plants), methods to insure, xiii, 120-54;
variations due to, 331-3
Croton Bugs, xii, 107
Croton Dam, iv, 119, 120 (fig.)
Croup, antitoxin in, x, 298
Crowberry, spread of, xiii, 342
Crow Blackbird, coloring of, xii, 245
Crowd-poisoning, i, 321
Crowds, psychology of, xi, 323-33;
leaders of, 332-3;
legal responsibility, 329-31
Crucibles, graphite, viii, 43;
platinum, 173
Crucible Steel Process, vii, 312

Cruickshank, William, electrical work, xvi, 122

Cruickshank, Wm. Cumberland, medical work, xvi, 179

Crusaders, coffee not known to, xiii, 232;
heroic crowds, xi, 326;
paper introduced by, v, 290
Crusades, effect on medicine, x, 37;
horse improvement by, xii, 307
Crust of Earth, xiv, 16;
chemical constituents, iii, 308, viii, 19, 90, 118, 129, 138-9, 148, 190-1, 192;
chemistry of, 190-203;
layers in, 191-2;
movements, iii, 76-98, xiv, 31-2, 33-9, 341
(see also Earth Movements);
rocks in iii, 12-14, 110-12, xiv, 17-19;
settling, cause of brontides, 196;
specific gravity, xiv, 11;
theory of formation, iii, 160;
thickness, 17, viii, 191-2;
waters in, iii, 113-29
Cryptograms, xiii, 63;
cycads and, 309;
earliest plants, 303;
forests of, of Silurian, xv, 71;
in coal age, xiii, 310;
numbers, 168;
reproductive process, 154-65;
spore-dispersal by wind, 344;
water necessary to fertilization, 300 (see Flowerless Plants)

Crystalline Form, iii, 309-11, viii, 203, 312-13;
solidification in relation to, iv, 163
Crystalline Rocks, iii, 378;
of oldest eras, 169, 170-1, 189

Crystals, Crystallization, iii, 309-20, 377-8;
cleavage, 310, 318, viii, 202;
electrification by cleavage of, iv, 260;
growth, iii, 311, 316;
growth of alum, viii, 313;
light polarization by, iii, 319-20, iv, 354;
Mitscherlich's studies, xvi, 161;
Pasteur's studies, 163-4;
snow and ice, i, 115-16;
water of, viii, 38;
X-ray studies, iii, 311, viii, 313

Ctesibius, discovery of compressed air, v, 109-11;
ignorant of atmospheric pressure, 112;
inventions and theories, xvi, 91-2;
water clocks, v, 59-62
Cuba, almiquis of, xii, 367;
American occupation, x, 160;
earthquakes in, xiv, 331;
jute production, xiii, 241;
sugar production, 215;
tobacco production, 258;
yellow fever eradication, x, 160-2, xiv, 356;
zoölogy of, 274-5
Cuckoos, xii, 255-6
Cucumbers, as food, viii, 365;
origin, xiii, 223
Cud Animals, xii, 311-12
Cugnot, Joseph, v, 207
Culinary Paradox, iv, 168-9

Cullen, Dr., refrigerating machine, v, 350, 354-6

Cullen, William, x, 88
Cultivated Plants, birthrate in, xiii, 51;
original sources, 221-7, xiv, 381-2
(see also Garden Plants)
Cultivation (soil), reason for, xiii, 92
Cultural Advance, requisites of, x, 107
Cumberland Plateau, xiv, 221;
height, 27
Cumberland Valley, xiv, 167
Cumene, viii, 235, 253
Cumulo-Nimbus Clouds, i, 102, 103-4
Cumulus Clouds, 1, 98, 101-2, 103-4;
air currents and, 293;
formation of, 93

Cuneiform Writing, xv, 174, 175 (figs.), xvi, 60

Curassows, xii, 261
Curie, Madame, radium discovery, xvi, 193
Curiosity, instinct of, xi, 55;
of crowds, 328
Curlews, xii, 262

Currents (water) power of, iii, 30-1, xiv, 39, 52-3

Current Transformers, vii, 44
Current Wheels, v, 76
Curtis, on spiral nebulæ, ii, 362
Curtis Turbines, v, 151, 152, 382
Curved Motion, forces producing, iv, 72-3
Curves, pitching of, iv, 67-9
Cusa, Nicolas de, xvi, 102
Custom, Cicero on, x, 135;
modesty and, xv, 254-5;
morality and, 286;
obedience to, how enforced, 374-5;
crowd psychology in, xi, 333
Customs Examinations, by X-rays, vii, 256-7
Cut-off, of steam engine, v, 146-7, 208
Cutting of Metals, v, 46-7, 54-5, 383;
by oxygen jet, i, 33

Cuttings, (plants) propagation by, ix, 337, xiii, 166, 167

Cutting Tools, of ancient Egypt, xvi, 66-7
Cuttlebone, xii, 79
Cuttlefish, iii, 260, 275-6, xii, 58, 78-9
Cuvier, biological works, xvi, 139, 148;
work on paleontology, 168
Cyanamide Process, i, 36, viii, 74, 153
Cyanide Solution, vii, 317
Cyanogen, xvi, 160
Cycads, iii, 251, 255, xiii, 309, 316, 317
Cycles, chemical, viii, 334-5, 349-50
(see also Carbon, Hydrogen, nitrogen Cycles)
Cycles, geographical and geological, xiv, 29
(see also Cycles of Erosion)

Cycles, of alternating currents, vi, 153, 154-5;
degrees of, 204

Cycles of Erosion, in land surfaces, iii, 33-6, xiv, 30, 34-5, 47-9, 155-64;
in mountains, iii, 135-6;
in shore lines, 56-7, xiv, 254-5
Cyclones, i, 135-8, 370, xiv, 349-50;
electrification by, vii, 212-13;
handling of ships in, i, 277-8
Cyclonic Thunderstorms, i, 138, 151
Cyclonopathy, i, 330, 370
Cyclonoscopes, i, 279, 370
Cyclops, (crustacean), xii, 84

Cygni, 61, measurement of distance, ii, 16, 315;
parallax, 311-12
Cygnus, nebulæ in, ii, 360;
new star in, 332
Cylinders, boring of, v, 44-5;
cooling, 159-61, 166-7;
in internal combustion engines, 157-61, 166-7;
of steam engine, 147;
pressure in, iv, 119
Cyme, flower form, xiii, 50
Cynodictis, xii, 346-7
Cypress Trees, in landscaping, xiii, 270;
in southern forest, xiv, 372

Czecho-Slovakia, public health fellowships, x, 172;
stone age remains in, 108 (fig.)
Daboia, xii, 231
Daddy Longlegs, xii, 90
Da Gama, Vasco, xiv, 309, 351
Daggers, development of, xv, 212
Daguerre, ii, 125
Daimler, Gottlieb, v, 213, 382
Dairies, electricity in, vii, 226-7
Dairy Products, drain on farm of, viii, 342-3
Daisies, flowers of, xiii, 49-50;
introduction to America, 353-4;
seed dispersal, 58-9;
stems, 23
Daisy Family, xiii, 206;
fertilization in, 144;
flower forms, 44 (fig.);
fossil species, 324;
in New Zealand, 380;
in pampas, 376;
original home and spread, 350, 353;
petal arrangement, 190;
seed dispersal, 344, 345
Dakin, antiseptic solutions of, x, 181-3, 382

Dakota Sandstone Formation, iii, 114, 115 (fig.)

Dalmatia, coast of, xiv, 252, 257;
harbors of, 268
Dalton, John, xi, 93, xvi, 133, 160, 162
Daltonism, inheritance of, ix, 340
Damaraland, desert plant of, xiii, 380
Damascus, swords of, v, 315
Damped Waves, vii, 264, 273, 286-8, 290
Dampier, William, i, 130, xvi, 114
Damping, in meters, vii, 159
Dams, beaver, xii, 295-6;
use of, v, 76, vi, 361, 364
Damsel Flies, xii, 105
Dances, Indian, xv, 305-6;
primitive, 310-12, 313, 316
Dandelion, family of, xiii, 206;
flower of, 49;
origin, 223, 353-4;
roots, 16;
seed dispersal, 58-9, 344
Daniell Cell, viii, 167
Dante, skull capacity, xv, 40
Danube River, delta of, xiv, 185;
historical importance, xv, 138-9;
longitudinal character, xiv, 154;
varied course, 155
Danzig, Poland and, xiv, 306
Darby, Abraham, v, 316
Dardanelles, important to Russia, xiv, 267
Dardanelles Expedition, i, 308
Dark Days, i, 56-7, ii, 211

Darkness, distinguishing of, by primitive animals, ix, 105;
effect on plants, xiii, 72, 76, 77, 84-90;
effects on plants, animals, and man, x, 253;
from interferences of light, iv, 377-8;
horrors of world of, 51;
periodic seeking of, xi, 52-3;
sleep and, 282, 288;
tuberculosis germ and, x, 290, 291
Dark Segments, i, 167, 371
Darning Needles (flies), xii, 105
Darwin, Charles Robert, x, 134-6, xv, 15;
book on fertilization of orchids, xiii, 145;
book on restless plants, 110;
epigenesis theory, xvi, 118;
experiment on destruction of seedlings, xv, 21;
experiment with tendrils, xiii, 112;
naturalist on "Beagle," 224, x, 134-5, xvi, 142;
on descent of man, xv, 56;
on emotions, xi, 131-3;
on expression of emotions by animals, xv, 64-5;
on fossil record, xiii, 302;
on Madagascar orchid, 48;
on self-fertilization, 135;
on sexual selection, xv, 274;
on variations, 334;

"Origin of Species," x, 135, xiii, 334, xvi, 148, 167, 181-2;
skull capacity, xv, 40
(see also Darwinian Theory)
Darwin, Erasmus, x, 134, xvi, 148

Darwin, George H., tidal friction theory, ii, 375-6, 377, 156-7

Darwinian Theory, x, 135, 136, xv, 15, 24-5, 56, xvi, 149-51, 152;

Bagehot on changes wrought by, xvi, 198;
Greek anticipation of, 79;
horror first caused by, xv, 53;
naturalism and, xvi, 111;
philosophical effects of, 195
Dassies, South African, xii, 304
Dasyures, xii, 278
Date Palm Tree, xv, 125
David's Deer, xii, 316
Davos, health resort, i, 210, 325
Davy, Edmund, xvi, 190

Davy, Sir Humphry, electrical work, vi, 16, 19, xvi, 122, 189;
heat studies, iv, 43, xvi, 131;
laughing gas discovery, x, 123-4, 125
Day, divisions of, v, 57, xvi, 57;
mean solar, iv, 15-16;
periods of high and low temperatures, i, 76, xiv, 347-8;
periods of highest energy, xi, 277
Day and Night Breezes, i, 131
Dayflies, xii, 104
Dead Reckoning, v, 65-6

Dead Sea, formation of basin, iii, 151, xiv, 118, 120-1;
level and level changes, iii, 151-2, xiv, 121, 205, 362;
salinity, iii, 152, viii, 139, xiv, 207
Deaf and Dumb, sign language of, xv, 148, 150
Deafness, ix, 103-4;
from brain disease, 146
Death, correlative of life, xii, 13;
"irritability" theory of, x, 86, 87;
James on phenomena of approaching, 242;
physiological meaning, ix, 17;
primitive conceptions of, xv, 327-9, 331-8;
vital knot in relation to, ix, 257
Death Adders, xii, 229

Debtors, treatment of, in African tribes, xv, 370

De Candolle, plant classification, xvi, 165-6;
vegetable table, xiii, 221
Decay, air and, xiii, 312-18;
carbon dioxide from, viii, 49, 61;
humus produced by, 340;
nitrogen from, 73, 346;
phosphorescence from, i, 346, 349, xii, 20

Deccan of India, lava fields, iii, 105, 228, xiv, 103

Deciduous Trees, xiii, 175, 269, 271-2;
of temperate forests, xiv, 370, 371, 372, 373, 374

Decimal System, xv, 181
Declination, of compass needle, iv, 247
Declination of Stars, ii, 299
Decomposition, (chemical), viii, 12, 101;
contrasted with dissociation, 121;
double, 104-5;
of salts, 117

Decrement, of oscillating currents, vii, 286, 287-8

Deeps, ocean, iii, 52, xiv, 9, 23, 286;
volcanoes and, 316
Deep Sea, animal life in, xii, 21-4;
animals, luminosity of, 139;
conditions of life in, 21-2;
darkness of, 22, xiv, 298;
density of, xii, 21;
deposits, iii, 54-5, xiv, 285, 286;
fish of, xi, 53, xii, 20, 23-4, 136, 138-9, 163, xvi, 146;
ground sharks of, xii, 143, 147;
movement of water in, xiv, 284, 298-9;
never over present continents, iii, 55;
ooze, xii, 18, 19;
plants of, 16-17;
seaweeds not found in, xiii, 72;
soundings of, xiv, 284;
temperature, 297, 298, 299;
topographical features, 284, 286-7, 288-90;
unknown to us, v, 202
Deer, xii, 317-20;
evolution of hoofs, iii, 300;
fear in, xi, 136;
heart in, x, 332
Deer Family, xii, 315-20
Deer-hunting, in India, xv, 223
Defectives, human, increase in, xv, 27
De Forest, audion detector, xvi, 191
Degrees, electrical, vi, 204
De Haen, x, 77
Dejection, emotion of, xi, 146;
posture and, 337, 338-40
(see also Despondency)
DeLaval Steam Turbine, v, 148-50, 382
Delaware Indians, prayer song of, xv, 346-7
Delaware River, estuary of, xiv, 40;
geological history, 40, 60, 168-9, 171;
heterogeneous course, 155;
rapids of, 159;
shad season in, xii, 155;
superimposed stream, iii, 233;
transverse characters, xiv, 99, 154, 167;
valley and gap, 50-1, 52, 169

Delaware Water Gap, iii, 233, xiv, 50-1, 167, 169;
rock weathering at, 76
Delco Automobile System, vii, 137
Delco Power Sets, vii, 232

De Lesseps, Ferdinand, Saharan proposal, xiv, 205

Deliberation, after contact and distance sensations, ix, 95, 121, 140;
nervous delays in, 140, 141, xi, 20, 21;
value of, 139
Delirium, Brown on, x, 89;
hot baths in, 311

Delta Connections (electric), vi, 210-11, 318, 325

Delphi, Oracle of, xv, 351-2
Deltas, iii, 32, xiv, 53;
alluvial soil of, 70;
coasts formed by, 53, 263;
in lakes, 202, 210-11;
lakes formed by, 203;
rivers joined by, 185
Delusions, x, 358-9
Demagnetization, vi, 37-8, 117, vii, 366;
by heat, iv, 253;
test, vi, 43
Dementia Precox, x, 237
Democritus, on knowledge, xvi, 87;
on matter, 83;
on origin of earth, ii, 366-7
Demosthenes, timed speeches, v, 62
Denatured Alcohol, viii, 250
Dendrites, xi, 18, 19;
receptors for pain, 117
Denmark, antiquity of man in, xv, 86-7;
föhrden of, xiv, 259;
forests and peat bogs, xv, 86-7
Density, absolute, iv, 110-11;
methods of determining, 111-12;
of liquids, how measured, 113, vi, 147;
of various substances, iv, 113;
specific, 111;
standard of, 149
Densmore, James, v, 312
Dental Arches, xv, 98 (fig.)
Dentistry, hypnosis in, xi, 316;
protection against pain, 121
Denudation (see Erosion)
Denver, boiling temperature in, iv, 170
Deodorants, inhibition in, xi, 81

Department Stores, Christmas lighting, vii, 342;
pneumatic tubes in, iv, 130;
rain and business, i, 265
Deperditometer, i, 319, 371

Depolarization, of electric cells, vi, 137, 139, vii, 366

Depression, of land and sea areas, (see Subsidence)

Depressions, (geological) in land, xiv, 204-5;
in ocean floor, 286

Depressions (meteorological), i, 135, 371 (see Lows)

Depth, perception of, ix, 119-20, xi, 173-85
Derborence, lakes of, xiv, 202
Derived Proteins, viii, 352-3
Derived Units, iv, 46, xvi, 131
Dermographism, xi, 317
Dermoid Cysts, x, 120
Desault, Pierre, x, 91-2
Descartes, influence of, x, 67;
mathematical and scientific work, ii, 15, xvi, 113-14, 118-19;
theory of vortices, ii, 60

Descriptive Astronomy, development of, ii, 15-16, 113-14, 119, 139

Deserts, density of air over, i, 171;
dust whirls, 60;
evaporation in, 323;
in trade wind belts, xiv, 355-6, 380;
irrigation by sun-power, v, 178;
lizards of, xii, 206;
mirages, i, 172-3, 174, iv, 328-9;
rainfall, i, 112;
rainfall and plants, xiii, 377-81;
rock weathering in, iii, 23, 71-3, xiv, 42, 77, 79;
salt deposits, viii, 197;

"stretching" of, xi, 173;
water-storing plants, xiii, 28, 30, 41-2, 104, 106-7, 336 (illus.);
wind action in, iii, 71-5
(see also Arid Regions)
Desert Sounds, i, 196, 371
Desert Topography, xiv, 41-2
Design, elements of (prehistoric), xv, 299
Designs, enlargement of by lanterns, iv, 342
Desires, suppression of, xi, 140-2
(see also Suppressions)
Despondency, indigestion and, xi, 370
(see also Dejection)

Detectors, wireless, iv, 315-16, vii, 261, 268-70, 278-80;
to guide ships, 284-5

Determiners, inheritance, ix, 329-42, x, 233-4, xiii, 330, xvi, 156

Detonation, of explosives, viii, 262
Detroit, steamers passing, xiv, 212
Devilfish, xii, 78, 148-50

Devil's Tower, Wyoming, iii, 111, 176 (Pl. 10), xiv, 129-30

Devil Whirlwinds, i, 60, 371
Devonian Period, iii, 20, 194-6, 378;
"Age of Fishes," 283, xv, 71;
animals and plants in, iii, 252, 271, 277, 278, 282-4, 285;
extension of sea in, 192 (fig. 37)
De Vries, variation studies, xvi, 153
Dew, i, 120-1, 371, xiii, 108;
former belief about, i, 119;
not formed on cloudy nights, iv, 183
Dewar, liquid air inventions, i, 31, vii, 323
Dewar Flask, viii, 68
Dew Bow, i, 177
Dew Point, i, 78, 79, 371
Dew Ponds, i, 352-3, 371
Dextrin, viii, 227-8;
in bread crust, 368;
molecules of, 356;
production and uses, 241, 243, 244
Dholes, xii, 345
Diabetes, ix, 290, 293-4, x, 276, 330
Diablerets, peaks of, xiv, 202
Diagnosis, art and science of, x, 366-79;
Brown's system, 89;
chest, 99, 371;
Egyptian study of, xvi, 70;
of infectious diseases (serum method), x, 215-17;

X-rays in, vii, 251, 254, 255, 256, x, 185-6, 372-4

Diamond Drills, v, 263, 264, 380;
in ancient Egypt, xvi, 67
Diamonds, iii, 328, viii, 42-3;
artificial, vii, 301, 311, xvi, 190;
cathode ray effects, 193;
cutting of, vii, 300, 309;
electrification, vi, 12;
in meteorites, ii, 292;
X-ray tests, vii, 257
Diana of the Ephesians, ii, 284
Diarrhea, ix, 249, x, 253, 307, 328
Diastole, arterial, x, 62, 63-4, 65;
of heart, 65
Diathermanous Bodies, iv, 182
Diatoms, deposits of, iii, 257-8, xiii, 67-8;
in tripolite, iii, 335;
in sea, xii, 17;
oil from, iii, 349;
oil storage by, ix, 28
Diatonic Scale, iv, 207
Dichloramin-T., x, 183, 382
Dicotyledons, xiii, 60;
antiquity, 207;
leaves and flowers, 176, 178;
leaves and stems, 177 (fig.);
subdivisions, 180, 189-90;
various families, 189-205
Dictation, memory after-images in, xi, 220
Dieffenbach, Johann Friedrich, x, 130

Dielectric, of condensers, iv, 264, vi, 302, 305, vii, 366;
in lightning, 206;
losses due to imperfect, 297-8;
strain, 366
Diesel Engines, v, 161-2, 382;
efficiency, 164;
fuel, 156;
in submarines, 199
Diet, bile in relation to, ix, 275;
deficiency of, diseases from, x, 255-68, 276;
fads of, ix, 285-6;
fats and proteins in, 300-1;
for reducing weight, 301-2;
mixed, man adapted to, 246, 285-6;
natural regulation of, 301, x, 255, 257;
need of amino acids in, 278;
nutrients in daily, viii, 366-7;
starch foods in ordinary, ix, 290, 300
(see also Foods, Nutrition)
Difform Motion, ii, 80
Diffraction of light, iv, 326, 378;
optical phenomena, i, 183-5
Diffraction of sound, iv, 52, 236-7
Digestion, ix, 226-46, x, 319-30, 353;
benefited by savory food, ix, 98, 241-2;
chemistry of, viii, 356-8;
color effects, xi, 96;
emotion effects on, ix, 165, 241;
enzymes in, viii, 103, 357 (see Enzymes);
excitement effects, xi, 374-5;
exercise and, 339;
fried foods and, ix, 286;
fruit stimulation of, viii, 365;
glucose in, 225-6;
historical studies of, ix, 239-40, x, 121, 128;
hot baths and, ix, 313;
in men and plants, xiii, 109;
of proteins, x, 204;
sleep in relation to, ix, 219, xi, 285;
soups as aid to, ix, 241, x, 320
(see also Indigestion)
Digging with water jets, v, 88
Digitalis, source, xiii, 256;
use of, in heart diseases, x, 333, 383

Dikes (geological), iii, 13, 110-11, 378, xiv, 106-8;
columns in, 130;
illustrations, iii, 102, 160 (Pl. 9);
veins and, 383-4
Dilated Stomach, ix, 85
Dimension, illusions of, xi, 186, 188, 189;
perception of, 162, 165, 171-2, 172-83
Dining rooms, lighting, vi, 275-6, vii, 69-70

Dinosaurs, iii, 288-93, 304 (Pl. 17), xii, 182, 194-5

Diœcious Plants, xiii, 47
Dionysus, worship of, xv, 352
Diophantus, xvi, 95
Dioptra, of Ctesibius, xvi, 91
Diphenyl, viii, 240

Dipper (constellation), moving clusters in, ii, 343

Diphtheria, x, 296-8;
antitoxin of, 197, 212, 213-14, 218, 296-8;
immunity to, 207, 298;
named by Bretonneau, 110;
toxin of, 196, 197

Direct Current Generators, iv, 307-8, vi, 159, 175-94, 344;
commutators on, vii, 364-5;
employment, vi, 215;
voltages, 159
Direct Current Motors, vi, 217-39;
in traction, vii, 182-3, 198-200;
on farms, 224;
speed flexibility, vi, 224-6, 229, 230, 232, 240-1

Direct Currents, vi, 152, 153-4, vii, 365;
ammeters for, vii, 166-72;
circuit-breakers for, 37, 39, 40;
conversion from alternating, vi, 330-48;
generation (See Direct Current Generators);
inductance in, 166;
lighting and magnetic effects, 155, 156-7;
open-circuited by condensers, 170, 304;
power consumed by, 165;
transformers unusable, 309;
transmission by, 160, 161, 195, 332;
uses, 152, 332;
used in electric furnaces, vii, 305-6;
used in electrochemistry, vi, 163;
used in electrotherapy, vii, 244;
used in smoke precipitation, vi, 164;
used in traction, 161-2, vii, 182, 186, 195;
value of current flow, vi, 164-5 (see Ohm's Law);
voltages, vii, 164;
voltages, production of high, 349-50;
voltmeters for, 154-65;
wattmeters for, 172, 173, 175
Direct Lighting, xi, 277, 373

Direction, perception of, ix, 117-18, 120, xi, 165, 167-71

Directional Wireless, i, 291, 302

Dirigible Balloons, iv, 107-8, v, 226-30, 382;
in forest service, i, 49
Disaccharides, viii, 224, 226-7, 375;
enzyme of, 357
Discomfort, atmospheric, i, 318, 320, 322;
senses of, in infants, ix, 351
Discordant Coasts, xiv, 249
Discouragement, conquering of, xi, 337-40
(see also Dejection, Despondency)

Discoveries, accidental, xv, 212-13, 232, 241-2;
great, usual way of, x, 40;
priority in scientific, 122
Disease Germs, x, 193-226, xiii, 71;
body resistance to, ix, 177-9, 185-7, x, 197-8, 203-12, xi, 34;
campaign against, x, 285-315;
discovery of, x, 194, 381, xvi, 143;
identification of, x, 150, 215-17;
in air, danger from, i, 325-6;
in sewage, viii, 326, 328;
in water supplies, 41, 318, 319;
man's struggle with, xv, 25-6;
"portals of entry," x, 198, 201-2.
(See also Infectious Diseases)

Diseases, anciently ascribed to spirits, x, 12;
atmospheric electricity and, i, 330;
"atom" theory of, x, 26;
Brunonian theory of, 89;
causes and factors other than infection, 227-81, 283;
causes of infectious, 193-226;
causes of, historical conceptions, 380;
climatic treatment, i, 331, x, 383;
diagnosis, (see Diagnosis);
electric treatment (see Electro-therapeutics);
habit in, xi, 248;
Hoffmann's nervous fluid theory, x, 85-6;
Humoral Doctrine of, 21;
hypnotic treatment, xi, 319;
infectious (see Infectious Diseases);
James on, x, 244;
lesion differentiated from, 98;
living causes, 193-226;
Locke on curing of, 75;
manifestations of, in organs, 318-65;
mechanical theory of, 23, 70, 71;
mental, 354-65;
mental factors in, 242-4;
metabolism, effects of, ix, 179, 302-4;
nature in cure of, x, 21, 73, 75-6, 84-5, 367;
occupational, 244-6;
Paracelsus on causes of, 48-9;
pneumatic theory, 26-7, 29;
prevention of, 282-317, xv, 49;
Pythagorean theory of, x, 18;
racial susceptibility to, xv, 47-52;
recognition of, x, 366-76;
savage conceptions and treatment, xv, 352-3, 359;
solidistic theory, x, 25-6;
specific, 196;
sthenic and asthenic, 89;
spread by tainted water, xiv, 140;
suppressed emotions and, xi, 140, 141;
Sydenham on meaning of, x, 73;
Sylvius's chemical theory of, 69;
thirst unimpaired in, ix, 89;
treatment of, x, 379-84
(see also Therapy);
tropical, xiv, 356-7, xv, 49-50;
Van Helmont's conception of, x, 68;
(see also Disease Germs)
Disgust, in various sentiments, xi, 146, 148
Disinfectants, viii, 332-3;
chlorine, 86, 274, 333;
formaldehyde, 219, 333;
hydrogen peroxide, viii, 41;
mercuric, 170, 333;
ozone, vii, 354;
sulphur dioxide, viii, 78, 333

Dismal Swamp, coal-forming conditions in, iii, 199

Displacement Currents, vi, 302, 305
Display Lighting, vi, 280, vii, 339-43;
colors in, iv, 51;
psychology of, xi, 344, 345, 346
Dispositions, sour and sunny, xi, 55

Dissection of human bodies, x, 30, 41-2, 45, 81

Dissociation, chemical, viii, 120, 121, 122, 375

Dissociation of Ideas, xi, 206, 209;
in mental troubles, x, 355, 360-1, 365
Distance, method of measuring, ii, 197-8;
perception of, ix, 118-19, 120, xi, 165-9, 173-89;
units of, iv, 283
Distance Senses, ix, 86, 96-121;
choice in relation to, 121, 140;
connections with brain, 142
Distillation, alcoholic, viii, 249-50;
apparatus, 213 (fig.);
fractional, i, 32, iv, 168
Distillation of coal, vii, 252-3
Distractions, fatigue from, xi, 277
Distress Signals, vii, 284
Ditch Grass, fertilization, xiii, 151-2
Ditching Machines, v, 216, 253, 254-5

Divers, compression and decompression, v, 120-1;
pressure on, i, 329
Diversion, need of, in brain work, ix, 138
Diving Bells, v, 115-16, 121
Divining Rods, iii, 123-4
Division of Labor, first form of, xv, 279;
in plants, xiii, 61-2
Divorce, xv, 290-1

Dizziness, from over-ventilation of lungs, ix, 266-7;
sensation of, xi, 64
"Doctor" Winds, i, 131, 371
Dodder, plant, xiii, 100, 101 (fig.)
Dodo, xii, 265
Dog Family, xii, 338-46
Dogfish, xii, 143, 146;
eggs of, 140;
name changed, i, 224
Dogs, xii, 344-6;
baboons and, 380;
canine teeth of, 333;
cat's hatred for, origin of, 355;
domestication of, xii, 345-6, xv, 197, 198;
embryological resemblances, 54;
employment in hunting, 223;
expression of emotions by, 64;
heat-loss regulation by, ix, 307-8;
hyenas and, xii, 351;
imitation in, xv, 66;
language methods of, 141;
mode of attack, xii, 354;
reasoning power in, xv, 68;
sense of smell in, ix, 97, 117;
wild, xii, 344-5;
zoölogical interest, xvi, 16
Dogwood, xiii, 271;
flowering, 45;
index plant, i, 255

Doldrums, i, 127, 129, 136, 371, xiv, 348, 349

Dollond, telescopes, ii, 100, 103, xvi, 125
Dolomite, viii, 149;
in refractories, vii, 307
Dolphins, xii, 297

Domestic Animals, development of, xii, 345-6, xv, 197-8

Dominants, in crosses, ix, 334, 335, x, 231, 233

Donati's Comet, ii, 275, 277, 280-1
Donkeys, xii, 308
Door-checks, pneumatic, v, 134
Doppler's Principle, ii, 119, iv, 209-10;
astronomical applications, ii, 123, 129, 133, 363

Dormice, xii, 291
Double Decomposition, viii, 104-5, 375
Double Images, xi, 175-81
Double Stars, ii, 122-4, 334-5;
colors, 296;
connections, 340;
proportion of, 320;
telescopes required for, 97-8;
theory of origin, 377
(see also Binary Stars)
Doubt, reasoning and, xi, 239-40;
retardization of impulses in, 20
Douglas Fir, forests, xiii, 340, xiv, 374
Dover, England, breakwater, xiv, 301
Doves, mating of, xv, 276;
plumage of neck, xii, 245
(see also pigeons)
Down, character of, xii, 244;
warmth of, x, 309
Downs of England, dew ponds, i, 352-3
Dowry System, xv, 285
Dragon Flies, xii, 105-6;
ancient, iii, 279, xiii, 308;
eyes of, xii, 102
Dragon Tree, xiii, 183-4
Drainage Systems, continental, xiv, 189-90;
development stages, iii, 33-4, xiv, 48, 49, 155;
earthquake effects, 335;

Ice Age changes, iii, 243-5, xiv, 60-1, 170-1;
joints and, 131

Drake, Daniel, x, 116

Drama, origin and development of, xv, 303-10, 322, 325;
sentiment in, xi, 151

Draper, Dr. Henry, astronomical work, ii, 17, 114, 116, 126, 130, 134, 135, 307, 358;
reflectors of, 103, 106

Draper Catalogue of Star Spectra, ii, 116-18, 146, 307, 309, 310

Dravidians, of India, xvi, 53

Drawing, development of art of, xv, 296, 298-9

Drawing Rolls, Arkwright's, v, 273-4, 376
Dreams, xi, 292-302;
images of, 221;
primitive conception of, xv, 328-9, 358;
psychoanalysis of, x, 364-5
Dredges, modern, v, 255-9, 381;
walking-machine, 216
Dried Foods, viii, 371;
antiscurvy vitamines in, x, 262, 266
Drift, Glacial, iii, 378 (see Glacial Debris)
Drills, ancient Egyptian, xvi, 67;
core, v, 263;
diamond, 263, 264, 380;
metal-cutting by, 47;
multiple, 53 (see Multiple Drills);
oil, v, 265-7;
pneumatic, i, 27, iv, 129, v, 129-30, 261-2, 263, 380, 381;
rock, 129, 261-2;
sonic-wave, 108;
spiral chisels, 46
Dropsy, polyuria in disappearance of, x, 344;
Van Helmont's idea of, 68
Droughts, i, 79, 371;
financial panics and, 263;
records of, in tree rings, xiii, 25;
springs and wells in, xiv, 136, 138

Drowned Valleys, iii, 37, 378, xiv, 40, 164, 255-6;
as harbors, 268
Drugs, blood riddance of, ix, 274;
coal tar, viii, 253;
in mother's blood, effects, ix, 343-4;
plant sources, xiii, 249-55;
pure food law on, viii, 370;
taste deadening by, xi, 72;
use of, in medicine, x, 21-2, 22-3, 30, 44, 45, 75-6, 77-8, 380-1, xvi, 109, 186-7

Drumlins, iii, 69, xiv, 60
Drums, xv, 316;
African, 313 (fig.)
Drupes, xiii, 54, 194

Dry Cells, iv, 297-8, vi, 59, 126, 127, 138, 143-4

Dry Docks, floating of ships in, v, 95
Dry Fogs, i, 96, 371;
of 1783, 57, 58-9
Dry Fruits, xiii, 54, 55-6, 57
Drying Machines, iv, 73
Dry Steam, v, 140
Duckbills, xii 272, 273
Ducks, xii, 257-8;
darkness effects on, x, 253;
primitive methods of hunting, xv, 222
Duckweed, xiii, 31
Ductless Glands, x, 346-53;
secretions used in therapy, 382
Dufrausne, x, 181
Duluth, Lake, iii, 149
Dunes, i, 53, iii, 71, 74
Duplex Telegraphy, vii, 112, 114-17, 376
Dupuytren, Guillaume, x, 130
Duralumin, v, 228
Duryea, Charles E., v, 213
Dust, atmospheric, i, 52-65;
atmospheric, elimination methods, ix, 269;
body handling of, 223-4;
deep sea deposits, iii, 54-5;
effects on light, i, 165, 183;
electric precipitation, vii, 216, 301-2, 347;
in cloud formation, i, 91;
in fog formation, viii, 304;
in stratosphere, i, 20, 144;
meteoric (see Meteoric Dust);
methods of measuring, i, 61-3;
physiological effects, i, 325;
volcanic (see Volcanic Dust);
wind-carrying of, i, 52-5, iii, 71, 73, 75, xiii, 344

Dust Count, Chicago standard, viii, 332
Dust-counter, i, 62, 371
Dust Whirlwinds, i, 60
Dusty Trades, i, 325
Dutch Language, relations of, xv, 160, 162
Dutchman's-pipe Vine, xiii, 131-3

Dyes, Dyeing, ancient Egyptian, xvi, 72-3, 74;
antiquity of use, xiii, 210;
chemistry of, viii, 258-60, xvi, 163;
coal tar, viii, 253-4;
importance of industry, 253-4;
purple, sources of, xii, 68, 72
Dynamic Electricity, vii, 367
Dynamic Heating and Cooling, i, 90
Dynamic Meteorology, i, 123, 371
Dynamite, viii, 261;
blasting with, v, 100;
invention, 380
Dynamo-Electric Machines, defined, vii, 367
Dynamometer, iv, 102, vii, 367
Dynamos, iv, 306-8, vi, 49-56;
discovery of principle, 22, 50;
function, 72;
Gramme's, 26;
interchangeability with motors, discovery of, iv, 54;
invention and development, xvi, 189;
parts, vii, 367;
pole pieces, 374;
separate and self-excited, vi, 186-7;
source of energy, 129;
submarine, double uses, v, 199;
voltage, on what dependent, vi, 131
(see also Generators)
Dynamotors, vii, 136-7
Dyne, unit of force, iv, 69-70
Dyrenforth, Gen. Robert, i, 338
Dysentery, amoebic, x, 195, 199;
from water pollution, viii, 318;
in tropics, x, 251, xv, 50;
overheating and, x, 307
Dyspepsia, from tight lacing, x, 309;
mental effects, xi, 369-70

Dysprosium, atomic weight and symbol, viii, 383

Eads, Captain, Mississippi River jetties, xiv, 270

Eagles, xii, 260, 261;
bald-headed, unions among, xv, 277
Earache, in children, ix, 104
Ear-mindedness, xi, 222
Ears, ix, 100-3, xi, 98-102;
basilar membrane of, iv, 203;
cartilage in, ix, 57;
direction perception by, 117, xi, 167-9;
disorders and care of, ix, 103-4;
equal size of, 169-70;
equilibrium organs in, 89-90;
hearing by, iv, 203-4 (see Hearing);
infections of, ix, 61-2, x, 219;
limits of hearing power, iv, 204, ix, 99, 100;
liquids of inner, iv, 203;
movements of, in animals, ix, 82, 117;
mutilations of, by savages, xv, 259;
nerve connections, ix, 124, 142, 143 (fig.);
origin, xi, 109;
outer, in hearing, ix, 117;
reddening of, in cold, 311;
receptor organs, attunement, xi, 62;
ringing in, iv, 203;
sensitiveness of, 204, 211-12, 360;
static sense organs in, xi, 126;
temperature of, ix, 93
Ear Trumpet, iv, 239
Earth, agonic lines of, iv, 246;
ancient ideas, xvi, 58;
antiquity, iii, 21, 43, 201, 218, xiii, 306, 314, 322, xiv, 29,

(see also Geological Ages);
axis mutation, discovery, xvi, 124;
center of universe, ii, 9 (see Geocentric Theory);
centrifugal force of, iv, 75;
changeableness of features, iii, 9-12, xiv, 3-4, 15-16, 28-30;
changes in historic times, xv, 72;
chemistry of, viii, 190-203;
climate in past ages (see Climate);
comets in relation to, ii, 279-80;
crust (see Crust of Earth);
density and specific gravity, iv, 98, 164, xiv, 11;
diameter, ii, 64, 192, iii, 51;
diameters, equatorial and polar, iv, 101, xiv, 9;
electrification, i, 144, 145-6, iv, 269, 270, vii, 207, 209-10, 212-13;
energy sources and losses, ix, 25-6;
geological history, iii, 164-248, xv, 70-1, 72-6;
gravity of, iv, 98-9, 101;
heat from sun, amount of, 194;
heat radiation and protection, 183-4;
Hindu conception, ii, 36;
interior, heat and condition, iii, 107-8, 120-1, 160, 162, iv, 164, xiv, 11-17, 312;
internal heat utilized, v, 178-81, ix, 25, xiv, 15;
internal waters, 151;
land and water distribution, 20-7;
life on, antiquity of, xv, 71;
life on, beginnings, xiii, 298-304;
life on, conditions necessary, ii, 242-5;
life on, origin of, xii, 9-13;
magnetic axis, iv, 250;
magnetic field and lines of, 252-253;
magnetic poles, 246, vi, 29-30;
magnetism, ii, 178, 186, iv, 248-50, vi, 12, 29, 39-40;
magnetism and internal iron, xiv, 11;
magnetism in relation to aurora, i, 159-61;
man's machining of, v, 251-67;
mass of, iv, 98;
motions (see Revolution, Rotation);
origin, ancient ideas, ii, 366-7, xvi, 77, 78;
origin, modern theories, ii, 373, iii, 158-63;
rigidity, 107-8, xiv, 17;
sciences of, xvi, 36;
shadow in space, ii, 206;
shape, 59, 69, 71, iv, 101, xiv, 9;
shape, ancient ideas, ii, 10, 28, 30, 34-5;
shrinking of, iii, 83-4, 108, 160, 162;
size, ii, 162, 163;
surface features, xiv, 9-11;
temperature layers, 13-15;
temperature ranges and control, ii, 243-4;
temperature regulation by atmosphere, iv, 183-4;
water circulation and supply, xiv, 134-5, 151;
waters, past and future, ii, 244;
waters within, iii, 109-10, 113-29;
weight, ii, 68-9, 76, iv, 98, 164;
wind and pressure belts, i, 128-9
Earth-Air-currents, i, 145, 371
Earth Movements, xiv, 32, 33-9;
importance to human life, 341
Earthquakes, iii, 92-8, xiv, 330-43;
faulting in, 39, 115, 128;
lakes formed by, 203;
submarine effects, 284;
water table affected by, 136

Earthquake Waves, transmission of, xiv, 17, 332-3

Earthworms, xii, 51-3;
power of distinguishing light, ix, 105
Earwigs, xii, 107
East Africa, ancient dinosaurs of, xii, 195;
clan ceremonies in, xv, 363;
development of, 136;
glaciers in, xiv, 54;
Great Rift Valley, 118-20, 121;
lava fields and volcanoes, 103, 317

East Indies, animals of, xii, 145, 288, 352, 353, 359, 362, 370;
beriberi in, x, 257;
chocolate growing, xiii, 234;
land and sea breezes, i, 131;
nautilus of, xii, 75;
nutmeg production, xiii, 261-2;
Portuguese and Dutch in, xiv, 310;
rattan palm of, 368;
smallpox inoculation in, x, 207;
spices from, xiii, 259;
wild arum of, 153
East River, pipe-thawing under, vii, 338-9
Eastport, Maine, tide at, xiv, 293

Eating, effect of excitement during, xi, 374-5;
kinaesthetic sensations in, 127;
metabolism increased by, x, 271;
obesity and, 273
Eccentric, of steam engine, v, 40-1
Echidnas, xii, 272-3
Echinoderms, iii, 259, 268-70, xii, 48-50
Echoes, iv, 237-9;
aerial, i, 190, 193
Eclipses, ancient studies of, ii, 9, 32, 37;
annular or ring, 214;
elements of, 216;
of Jupiter's moons, 263;
of moon, 206-8;
of sun, 209-18
(see also Solar Eclipses)
Ecliptic, ii, 162, 350;
plane of, 70, 163;
poles of, 92;
trepidation of, 38
Ecology, xiii, 354-7
Economic Botany, xiii, 208-66
Economic Geology, iii, 342-76, xvi, 172-4
Ectoderm, xii, 26
Ecuador, glaciers in, xiv, 54;
yellow fever in, x, 160, 172-3
Eddies, wind, i, 292, 294, 371

Eddington, astronomer, ii, 17, 330, 341, 342, 347, 348-9, 354, 356, 382;
quoted, 151, 320, 344, 384;
"Stellar Movements," 319
Eddy Currents, vi, 192, vii, 365-6;
in various machines, vi, 213, 225, 316

Edinburgh University, medical school, xvi, 179

Edison, carbon lamp, v, 381;
carbon lamp filaments, xvi, 189;
carbon microphone, v, 381;
early dynamos, xvi, 188;
electrical work, vi, 26;
father of electric lighting, vi, 265;
first incandescent lamp, xvi, 188;
kinetoscope, v, 330;
phonograph, 328, 381;
quadruplex telegraph system, vii, 112;
storage battery, vi, 149-51;
vacuum tube discovery, vii, 276;
Edison Closed Circuit Cell, vi, 137

Edison Electric Company, load factors, vi, 381-2;
storage battery reserves, 382-3;
tied with Interborough System (N. Y.), 384
Edison-Lelande Cell, vi, 139-40
Edison Storage Battery, vi, 130, 149-51

Education, association principle in, xi, 200-1, 203, 204;
botanical, xvi, 22;
environment in, xi, 249;
grasping reflex, importance, 43;
hygienic, x, 282-5;
imitation in, xv, 66-7;
importance of choices in, xi, 266-7;
language and, xv, 145-6;
modern, a summary of past, 145-6, 164;
modern, beginnings, xvi, 111;
necessity of, ix, 344, 352;
progress in relation to, xv, 30-1, xvi, 47;
reaction speeds, xi, 158, 159;
sensation as, 68;
Spencer on, x, 282, 284;
waste of time in spelling, xv, 177;
(see also Learning Processes)
Eelgrass, fertilization, xiii, 150-1
Eels, xii, 162-3;
vinegar and paste, 45
Effector Neurones, xi, 21, 22, 26;
in embryo, 34
Efficiency, human, viii, 367, ix, 296, 306;
climatic effects, x, 238-9, xiv, 357, xi, 369-82;
temperature effects, i, 323-4

Efficiency, industrial, xi, 360, 362, 363

Efficiency of Machines, iv, 192, vi, 214, vii, 367;
electric lamps, vi, 268;
generators, 357, 379;
heat engines, highest attainable, iv, 192;
motors, vi, 228;
power plants, 380-3;
transformers, 317-18;
various kinds of engines, v, 155, 161, 164, 170, 172

Egg Cells, production and development of, ix, 332-3, 335, 339, 343-4

Eggs, albuminuria from eating of, x, 345;
amino acids in, 278;
boiling of, viii, 368;
boiling of, on mountains, iv, 170;
calories in, ix, 299;
composition and use, viii, 364;
poisoning from, x, 212;
vitamines in, viii, 369, ix, 33, x, 260, 261;
white of, composition, ix, 176;
white of, digestion of, 233
Egrets, xii, 244, 255

Egypt, antiquity of civilization in, xiv, 196, xv, 84;
bats of, xii, 371;
buffaloes in, 329;
cats of, 355;
geographical changes in, xiv, 33;
lions of, xii, 359;
locust plagues, 109;
Nile inundation, xiv, 70-1;
Nile valley fertility, 53, 71, 219;
Pyramids (see Pyramids);
rock weathering in, xiii, 23, xiv, 78-9;
snowfall in Lower, i, 210;
storks of, xii, 255;
ziczac of, 263
Egypt (Ancient), agriculture, xiii, 210;
astrology and astronomy, ii, 21, 23-6, xv, 269-70, xvi, 69, 70, 71;
baboons in, xii, 380-1;
brick-making in, xv, 267 (fig.);
calendar, xvi, 70;
civilization conditions, xv, 123, 127;
crocodile in, xii, 199;
dogs of, 346;
donkeys in, 308;
duck-hunting in, xv, 222;
hairdressing in, 255 (fig.);
history and civilization, xvi, 53, 65-75;
humped cattle of, xii, 330;
hunting dog of, 345;
irrigation methods, iv, 27 (fig.), v, 18-19, 178, xv, 240;
machines, v, 42;
medical science, x, 11, 12, 31, xvi, 82;
monuments and temples, ii, 24-6, 165;
musical instruments, xv, 314, 317, 318, 319;
papyrus, v, 289-90;
peoples, xvi, 64-5;
plague of blood, i, 358;
poppy cultivation, xiii, 253;
pottery-making in, xv, 249-50, 251 (fig.);
sacred ibis of, xii, 255-6;
sacred ichneumons of, 352;
sailing vessels, v, 182;
sciences, xvi, 54-75, 77, 96;
scribes of, xv, 177 (fig.);
slavery in, 378-9;
spinning and weaving in, 243, 244, 245, 246 (figs.);
stone-cutting in, 271 (fig.);
stone-moving in, 270-1;
sun-worship, ii, 20, 23, 24, 25-6;
tops, v, 339;
water clocks, 58-62;
weapons of, xv, 211 (fig.);
wheat in, xiii, 210;
wheel in, v, 18-19
Egyptian Art, xv, 300-2;
no perspective in, xi, 181
Egyptian Comet, ii, 134
Egyptians, ancient and modern, xvi, 65;
ideas of cosmos, 77;
ideas of insanity, x, 356;
in Mediterranean group, xvi, 49;
not seamen, xiv, 265, 306-7;
scarabs of, xii, 123
Ehrlich, Paul, "atoxyl" of, x, 169;
chemotherapy founded by, 381;
immunity theory, 209, 211-12
Eiffel Tower, hail rods, i, 342, 344;
horizontal rainbows seen from, 177
Einstein Theory, ii, 79-82, xvi, 196-8;
æther constitution and, vii, 368;
anticipations of, xvi, 85;
Newtonian system and, iv, 18
Elands, xii, 327
Elasmosaurus, xii, 202
Elastic Cords, vibrations, iv, 216
Elasticity, iv, 35-6, 156-9;
molecular, perfect, viii, 24;
temperature effects on, iv, 198;
vibration dependent on, 198, 213, 215, ix, 98, 100-1

Elation, in various sentiments, xi, 140, 150
Electrical Capacity, iv, 267-8
Electrical Conductors (see Conductors)

Electrical Machinery, remote and automatic control, vi, 99-101;
ratings, 192-4, 212, 317
Electrical Protective Devices, vii, 32-50
Electrical Terms, vii, 361-76
Electrical Units, iv, 284-5
Electric Arcs, direct currents best, vi, 332;
extinguishing of, 102;
Faraday's experiments, xvi, 189;
heat of, iv, 312, vi, 348;
heat and light, 280;
on alternating circuits, vii, 208-9;
used in nitrogen production, 323-4 (see Arc Process)

Electric Batteries (cells), iv, 271-3, 295-300, vi, 58-62, 126-51, vii, 363;
chemical action, viii, 167-9;
defined, iv, 381, 382;
depolarization, vii, 366;
direct currents, vi, 154;
direction of currents, 59;
function, 72;
invented by Volta, 18-19;
local action, vii, 361;
polarization of, iv, 296, 298, 383;
primary and secondary defined, iv, 383;
used in electrotherapy, vii, 241-4

(see also various kinds of batteries and cells)

Electric Bell, iv, 290-2, vi, 99, 127, 138, 144, 306

Electric Breeze, vii, 238-9

Electric Cars, circuit-breakers in, vi, 101-2;
construction, types, and operation, vii, 182-6;
former and present feeling about, 75-6;
growth and improvement, 180;
movement on hills, vi, 232-3 (see Electric Traction)

Electric Clocks, v, 74

Electric Currents, vi, 67-85;
alternating and direct, 152-3 (see Alternating, Direct Currents);
attracting and repulsion of, 20-1;
cause of, iv, 265, 271, 273, vi, 46, 72;
detection, 91;
direction, 54-7, 59, 124;
distribution (see Power Transmission);
effects on human body, vii, 246-9;
electron theory, vi, 123, 152, vii, 366;
flow, vi, 46, 47, 67-9;
follow least resistance, 96;

Galvanic Faradic, and Franklinic, vii, 242, 243, 245;
heat and light production by, iv, 310-12, vii, 337-8;
induced, iv, 303-8, vi, 22 (see Induced Voltages);
intensity, vii, 370;
leakage, 371;
magnetic effects of, iv, 273-9, 286-7, vi, 20-1, 88-91;
measured by ammeters (see Ammeters);
overloading lines, vi, 9, 72;
production, 46, 72

(see also Dynamos, Electric Batteries, Thermal Couples);
protection against overloading, vii, 34-50;
selenium control valve, v, 332;
surges, vii, 16-18;
units and measurements, iv, 277-85, vi, 69-76, 82, 84-5;
values, effective and maximum, 346-7;
value in oscillating circuits, vii, 289-90;
velocity, Watson's study, xvi, 123;
wire capacity table, vii, 58

Electric Discharges, iv, 264-5, 267, 269, vii, 366;
atmospheric, i, 157, 158-62;
fog dispersal by, 94;
in vacuums, iv, 317-18;
nitrogen fixation by, viii, 73, 74, 346;
rain-making by, i, 340;
through gases, vii, 216, 301-2
Electric Eel, vi, 16, 64, xii, 160-1
Electric Energy, vii, 368;
conversion into heat, 89, 303-5;
due to difference of potential, iv, 263, 264, 265;
equivalents, vii, 382;
transmission (see Power Transmission);
unit of, vi, 82;
unit (joule), iv, 284, 294, 310, 312, vii, 370

Electric Fans, vii, 76-7, ix, 317
Electric Fishes, catfishes, xii, 161;
electric eel, 160-1;
torpedo fish, 149-50
Electric Furnace, iv, 312, vii, 302-12;
history and uses, xvi, 189-91;
invented by Acheson, vii, 301;
operation and products, viii, 283-4
Electric Hammer, vi, 94
Electricity, iv, 256-321 vols. vi, vii;
advantages in home and industry, vii, 51-2;
animal (see Animal Electricity);
atmospheric, i, 141-63, vii, 201-19, 362;
attraction and repulsion law, iv, 256-8, 261, vi, 18, 122;
basis of matter, iv, 23, vi, 107-8, 113, 118 (see Electron Theory);
battleship applications, vii, 325-35;
chemistry and, viii, 164 (see Electrochemistry);
commercial units, iv, 312;
conductors and nonconductors, 258-9, vi, 294-5 (see Conductors, Nonconductors);
daily applications, xvi, 19, 20, 26-7, 30;
defined, vii, 367;
disadvantages in mines, v, 129;
farm uses, vii, 220-34;
flow, vi, 46, 67, 292-3;
flow, direction of, iv, 265, vi, 56-7;
frictional (see Frictional Electricity);
history of development, iv, 52-5, vi, 9-26, xvi, 121-3, 188-92;
home applications, vii, 73-90;
identity of kinds, vi, 23;
importance of understanding,
9-10, 64-6;
late discovery and use, vii, 235;
lightning and, vi, 10-11, 13-16;
magnetism and, iv, 257, 276, vi, 12, 19-20, 21, 27-8, 86;

"messenger" of physics, iv, 50;
miscellaneous applications, vii, 336-59;
name, origin of, iv, 256, vi, 12;
not made, but moved, 46, 49, 72, 128;
origin, latest views of, 105-25;
physical effects of, x, 250, 254, xi, 117;
popular applications of, iv, 10;
positive and negative, i, 141, 142, iv, 258, 265, vi, 287;
precise measurements, vii, 152;
production of (see Electric Batteries, Generators, Power Plants);
production by wind power, i, 38, v, 173;
quantity unit, iv, 261, 277, 280, vii, 365, 374;
science of power, xvi, 36-7;
single-fluid theory, vi, 11, 288-93;
static (see Static E.);
transmission (see Power Transmission);
uses and power, vi, 10;
use in medicine (see Electro-therapeutics);
wave lengths and frequency, vii, 260;
wide familiarity with, 152-3;
widespread interest in, vi, 330-1 (see further Electric Currents, Electric Power, Electromotive Force, etc)

Electric Lamps, iv, 310, vi, 265-8;
candlepower of, iv, 352, xvi, 189;
detonation on breaking, vii, 211;
Edison's inventions, xvi, 188, 189;
energy requirements, iv, 311;
light and heat, vi, 268;
neon and argon fillers, i, 33;
number used, vii, 51;
short-circuiting by burning out, 35
Electric Lighting, vi, 264-83;
advances in applications of, iv, 50-1, vi;
direct and alternating current effects, 155-6;
due to glowing of a solid, viii, 60;
farm uses, vii, 231, 232, 233;
fire hazard reduced by, vii, 51;
history, xvi, 122-3, 188, 189;
homes and interiors, vi, 275-8, vii, 68-72, 75;
leading inventors, vi, 26, 265;
meter units, iv, 312;
outdoor, vi, 278-80, 283, vii, 339-4;
small fraction of power used in, vi, 381;
wide use and advantages, vii, 51, 52

Electric Locomotives, v, 212, vi, 161, 162, vii, 182;
induction motors in, vi, 249;
motors and currents, vii, 195-6, 200;
power and efficiency, 193-4;
regenerative brakes, 200
Electric Meters, vii, 151-79;
for alternating currents, vi, 346-7;
screening of, 32;
units used in, iv, 312, vi, 82-3

Electric Power, costs, on what dependent, vi, 380-2;
costs for farm work, vii, 224-6;
extra charges for peak hours, vi, 301, vii, 177-8;
measured in watts, iv, 310, 312, vi, 84-5;
transmission (see Power Transmission);
water power and, viii, 283
Electric Pumps, vii, 86-7;
remote control, vi, 99-100
Electric Ranges, vii, 88-9;
special rates for, 174
Electric Traction, vii, 180-200;
block signals, 355;
converters used, vi, 342;
current used, 161-3;
motors used, 231, 241
(see also Electrification of Railroads)
Electric Waves, discovery of, iv, 55, 313
(see also Electromagnetic Waves)
Electric Wiring (see Wires, Wiring)

Electrification, iv, 256-62, vi, 11, 12, 13, 286;
degree of, 17;
methods of, iv, 265-7;
of atmosphere, vii, 207, 212-13, 216-17;
of earth and air, i, 144-6, 150
(see also Charged Bodies)

Electrification of Railroads, v, 212, vi, 162, 249, vii, 181-2, 193-6;
block signal system, vii, 359;
brake system, 200;
smoke relief by, i, 64;
trolley and third rail systems, vii, 197-8
(see also Railroad Terminals)
Electrochemical Analysis, viii, 294-5

Electrochemistry, vii, 299-324, viii, 164-9, 283-4, 312;
organic, 266;
use of direct current in, vi, 163;
water power and, viii, 267

Electrodes, iv, 297, 317, 382, vi, 60, 129, 130-5, 367;
graphite, vii, 308, 309

Electrolysis defined, iv, 382, vii, 367, viii, 375;
industrial applications, vii, 312-24, viii, 164-7, 271, 272, 284;
ionic hypothesis of, viii, 123-5;
of organic compounds, 266;
of water, 30-1
Electrolytes, iv, 382, vi, 23, 58, viii, 376;
acids, bases, and salts called, 125;
action of currents in, vi, 131-5, vii, 247;
don'ts about, vi, 149;
double-fluid, 137;
in primary and secondary cells, 130
Electrolytic Cells, vii, 313, 367
Electrolytic Corrosion, vi, 65-6, vii, 189;
alternating currents and, 305

Electrolytic Dissociation, viii, 123-4, xvi, 164-5

Electromagnetic Units, iv, 278-82

Electromagnetic Waves, form and lengths, vii, 371;
length and frequency, 259, 260;
transmitted by æther, vi, 119, 269
(see also Radio Waves)

Electromagnetism, Electromagnets, iv, 286-94, vi, 30, 31, 86-104, vii, 367, 372;

Einstein theory and, ii, 80-1

Electromotive Force, defined, iv, 271, 294, 382, vi, 46-9;
dangers of uncontrolled, 64-5;
generation, 49-66 (see Electric Batteries, Generators, Thermal Couples);
induced and generated, vii, 370;
measured in volts, iv, 280-1, 284, vi, 53-4, 57;
phase relations, 167-9, 171-4, 242;
self-induction, vii, 375;
uses, vi, 56
(see also Voltage)
Electromotive Force Waves, vi, 198-200, 208
Electromotive Series, viii, 127-9, 376
Electrons, vi, 113-15, vii, 367;
beta rays, viii, 185, 186;
from sun in upper air, i, 144, 146;
in charged bodies, 142, 143;
in sun, ii, 177-8;
knowledge of, from radioactivity, viii, 307;
motions in light, heat and electricity, vii, 371;
nature, vi, 118, 120;
negative electricity, viii, 187-8;
original study, xvi, 193;
size and weight, i, 141-2, viii, 187;
speed in cathode rays, iv, 318

Electron Theory, iv, 321, vi, 26, 122-5, vii, 366, 367, 371, viii, 187-8;
compared with Franklin's theory, vi, 288, 292;
in various electrical actions, 133-4, 152, 153, 284, 288, 302, 338-9, 340;

Larmor's proposal, xvi, 193

Electroplating, vii, 314-19, 374, viii, 164-6, 284

Electro-Refining, vii, 319-21, viii, 166-7, 284

Electrostatic Fields, iv, 261-2, vii, 368;
intensity of, 370
Electrostatic Generators, vi, 298-301
Electrostatics, defined, iv, 259;
importance of, 271
(see also Charges, Charged Bodies)
Electro-Therapeutics, vii, 235-57, 368
Electrotyping, vii, 313-14
Elements, vi, 108-9, viii, 12, 16, 376, 383;
atomic numbers, 183, 309;
atomic weights (see Atomic Weights);
classification, metals and nonmetals, 17-19, 126, 175-7;
discoveries through Mendeléeff's tables, 180, 181, 182, xvi, 163;

Greek idea of primary, 81, 83;
in earth's crust, iii, 308, viii, 19, 190-1, 192, 194;
in heavenly bodies, 302;
in meteorites, ii, 292;
in sea water, xiv, 295;
in stars, ii, 115-18;
in sun, 114, 128, 185, 211;
isotopic and isobaric, viii, 189;
made up of molecules, 26;
number, 16, 183, 309;
only things man cannot produce, vii, 310;
origin in silicates, viii, 193;
origin, remarks on, 84;
periodic classification, 177-83;
physical state and chemical properties, 297-8;
potentials against hydrogen, vii, 383;
properties dependent on atomic weights, xvi, 134;

Prout's hypothesis of hydrogen basis, viii, 177;
radicals or groups, 93;
radioactive, 184-9;
spectra of, ii, 113, viii, 302;
symbols, 91, 383;
tests of, 285-91;
transmutation of, 188-9, xvi, 14-15;
union types, viii, 20-1, 99-100;
valency, vii, 384, viii, 93, 122
Elephants, xii, 301-4;
breeding and domestication of, xv, 197;
breeding rate, 20;
evolution, iii, 300;
fearlessness, xi, 136;
formerly in Europe, xv, 76, 92;
strength of, 18;
trapping of, 225, 226 (fig.), 227;
trypanosome in, x, 168

Elevation (geological), denudation increased by, xiv, 39, 40;
effects on streams, 163, 164-70, 187-8;
instances of, 33-4;
of coasts, 253, 262;
of ocean floor, xiv, 286
(see also Level Changes, Rejuvenation)
Elevators, air cushioning, v, 134-5;
first passenger, 380;
hydraulic, 102-3;
motors used, vi, 231, 234;
power for fast and slow, 83, 85;
sense of giddiness in, xi, 126-7
Elk, xii, 317, 318
Elm Trees, xiii, 194, 271-2
Embroideries, machine-made, v, 285-7

Embryo, development in man and animals, xv, 54, 55;
development of human, ix, 343-4;
development of nervous system in, xi, 34-6;
flexed form of hand, 42-3;
gill slits and notochord in, xii, 128;
of mammals, 273;
of marsupials, 274;
past stages of race seen in, xv, 53-4;
semiaquatic conditions, xi, 36
Embryo, of plants, xiii, 60

Embryological Development, x, 228 (see Embryo)

Embryology, history, xvi, 107, 156
Emeralds, iii, 325;
oriental, 327

Emergencies, body responses in, ix, 166-7, 171-2, 209, 220, 221, 293

Emerson, metaphor of, i, 187;
on common mind, xi, 152;
on narrowness of men, 376
Emery, iii, 327-8
Emmet, Thomas, x, 122, xvi, 186
Emotional Glycosuria, xi, 138
Emotions, xi, 129-42;
associations
determined by, 205-6;
brain processes in, ix, 154;
classes of, 153-4;
combinations in sentiments, xi, 146-50;
expression of, in men and animals, xv, 63-5, 152;
fatigue and, xi, 274-6;
hypnotic suggestion of, 317-18;
in crowd psychology, 331-2;
not localized in body, 62;
pain and, 119, 120;
physiological effects of, ix, 163-7, 171-2, 200, 209, 240-1, 348, x, 339, 353;
primary varieties, xi, 55-6;
suppression of, 140-2
(see also Suppressions)
Empathy, xi, 172-3, 186;
in advertising, 346-7;
in salesmanship, 335
Empedocles, atomic theory, xvi, 87;
malaria prevention by, x, 154;
on matter, xvi, 83, 118
Empiric Doctrine (medicine), x, 24, 28
Emu, xii, 243, 249, xv, 194

Emulsions, colloidal state, viii, 314, 316, 356;
defined, ix, 289
Encke's Comet, ii, 280;
used to find Mercury's weight, 77
End Buds, of fishes, xii, 137
Endless Screw, v, 38, 37 (fig.)
Endocarditis, x, 195, 332
Endoderm, xii, 26
Endoskeleton, xii, 127
Endothelial Cells, x, 197, 210

Energy, conservation of, iv, 40-1 (see Conservation of Energy);
defined, 13-14, 37-9;
equation of, 78;
force contrasted with, 41;
forms and transformations, 81-8;
future sources of, v, 171-81;
heat equivalent (see Mechanical Equivalent of Heat);
kinetic and potential, iv, 79, 81-5, vii, 368;
matter and, iv, 13-14;
of plants and animals, viii, 334, 335, 336, 347, 349, 350

(see also Human Energy);
physics as science of, iv, 12, 13-14, 50;
power differentiated from, 80;
radiant (see Radiant Energy);
sources in nature, viii, 267-8, ix, 25-6, xiv, 31-2;
sun as source of, v, 177, viii, 267, 334, 350, ix, 25-6, xiv, 32;
transference and transformation of, iv, 37-41, 81-88, vi, 128-9;
units of, iv, 79-80, ix, 295;
unit equivalents table, vii, 382;
universality of, iv, 13-14;
work and, 37-40, 78-88;

(see also Atomic E., Chemical E., Electrical E., Human E., Molecular E., Power)

Engines, air and water cooled, v, 160-1;
Clausius's principle, xvi, 135;
heat, efficiency of, iv, 192;
reciprocating and rotary, v, 148;
two-cycle and four-cycle, 157-9;

(see also Gas Engines, Gasoline Engines, Internal Combustion Engines, Steam Engines, etc.)

Engines of Destruction, v, 359-75
England, Alpine Invasion, xvi, 49;
beet cultivation in, xiii, 216;
"Blackthorn winter," i, 363;
chalk deposits, iii, 266;
climate of, xiv, 345;
coal supply, v, 172;
coast destruction, iii, 56, xiv, 47, 301;
coffee consumption, xiii, 232;
early criminal justice in, xv, 372;
first recorded eclipse, ii, 210;
former connections with Europe, xiv, 271-3, xv, 76;
grass snake of, xii, 217-18;
insular position and results, xiv, 279-81, xv, 137;
iron industry, v, 316;
jute manufacture, xii, 243;
lakes of, xiv, 200;
landscape gardening, xiii, 267, 268;
maritime supremacy, xiv, 262, 280-1, 307-8, 310;
oak-hazel copses, xiii, 369-70;
primitive inhabitants, xv, 83, 92-3;
rainfall and verdure, xiv, 352;
recent restrictions on power vehicles, v, 212-13;
smallpox inoculation in, x, 207;
sugar in, xiii, 215;
surgery made a profession, x, 105;
tea in, xiii, 228-9;
tobacco introduction, 256;
trees in, xiv, 375
English Alphabet, xv, 176

English Channel, first aeroplane flight, i, 43;
historical importance, xiv, 279-80, xv, 137;
impassable to quadrupeds, xiv, 273;
tidal power system, v, 175-6;
tides of, xiv, 294
English Language, changes in, xv, 156-7;
double meanings of words, 158-9;
foreign words in, 161;
imitative words in, 153-4;
origin of various words, 157, 161;
relationships, 160, 162;
spelling and pronunciation, 176-8
English People, characteristics, xiii, 172;
insularity of, xiv, 280
English Sparrow, increase in U. S., xv, 21
Entada Scandens, xiii, 347-8
Enterokinase, x, 326
Entropy, iv, 193, xvi, 135

Environment, adaptation to (see Adaptation to Environment);
change of, to relieve fatigue, x, 247;
changes of, new species from, xv, 24-5;
defined, x, 228;
geographical, influence on civilization, xiv, 30-1, xv, 31, 122-39;
habit and, xi, 249;
health and disease factor, x, 237-44, 249-55, 303;
heredity and, ix, 344, x, 228-30, xvi, 47;
instincts as response to, xi, 49-53;
man creature of, 57-8;
man's conquest of, xv, 25-6;
man's regulation to, x, 249-51;
man the product and molder, of, xi, 33;
mental effects of, x,
354;
mind as response to, xi, 12, 24, 58;
plant response to, xiii, 355-7;
selection of, xi, 257;
will and, 265
Envy, sentiment of, xi, 148
Enzymes, viii, 376, ix, 227, xiii, 83;
in digestive processes, viii, 103, 226, 228, 357, 358, ix, 227, 228, 229-30, 235, 242;
in infants, ix, 346;
in tea, xiii, 230;
in tobacco curing, 257
Eocene Period, animals of, xii, 306, 366;
birds of, xv, 71
Eolithic Period, xv, 103-5
Epic Poetry, development of, xv, 321
Epicurus, atom theory, x, 26
Epicycles, ii, 35-6
Epidemics, Sydenham on, x, 74;
tainted water and, xiv, 140
Epigenesis, xvi, 118
Epileptics, multiplication of, x, 235-6;
primitive ideas of, xv, 350, 353
Epiphytes, xiii, 185, 362-3, 366;
in tropical forests, xiv, 368
Epithelial Cells, x, 201, 202
Epsom Salts, viii, 149
Epyornis, eggs of, xii, 249
Equator, altitude of stratosphere at, i, 20;
bulging at, ii, 69, 71;
magnetic, xiv, 246;
of wind system, xiv, 347;
solar eclipses seen at, ii, 215;
upper air temperatures, i, 20;
weight of bodies at, ii, 69, iv, 75, 101;
winds at, i, 127, xiv, 351

Equatorial Belt, winds and weather of, xiv, 348, 349

Equilibrium of Chemical Reactions, viii, 103-5, 190-1

Equilibrium of Forces, v, 183-4;
science of, iv, 25

Equilibrium Sense, ix, 89-90, 156, x, 126, xi, 64, 126, 127;
in infants, ix, 350
Equinoxes, defined, ii, 70-1;
observed in Egypt, 25, 26, xv, 269-70;
precession of (see Precession of Equinoxes)
Eras, Geological, iii, 19-21, 378
Erasistratus, x, 23-4
Eratosthenes, ii, 10, 30
Erbium, symbol and atomic weight, viii, 383
Erg, energy unit, iv, 80;
table of equivalents, vii, 382
Ericsson, air engine, v, 380;
Monitor, 380;
solar engine, ii, 169;
steam fire engine, v, 378

Erie Canal, importance to New York, xiv, 267-8;
through Mohawk Valley, 194
Erie, Lake, salt in, viii, 139;
water constituents, 40;
water supplies from, v, 260-1
Ermines, xii, 349-50
Eros (asteroid), ii, 191;
distance, 132, 259
Erosion, iii, 28-9, 378;
agents and processes, xiv, 39-79

(see also Glaciers, Ocean Waves, Streams, Wind);
bad lands and canyons due to, iii, 139-40;
base level, 30, 377 (see Base Level);
by ground water, xiv, 141, xvi, 173;
cycles (see Cycles of Erosion);
earth movements and, xiv, 39, 40;
final effect of, 80;
illustration of recent, iii, 64 (Pl. 3);
in deserts, 72;
in Ice Age, 242;
of faulted areas, xiv, 127;
of folded areas, 94-6;
of mountains, iii, 135, 139, 140-1, 188, 190-1, xiv, 233-4;
present relief due to, iii, 32;
rate of, xiv, 41;
unequal operation of, 35
Erosion Surface (see Unconformity)
Errors, fatigue and, xi, 274;
of memory, 215-17;
in space perceptions, 183-90
(see also Mistakes)
Erysipelas, germ of, x, 195;
immunity to, 207;
puerperal fever and, 114
Eskers, iii, 70, 352 (Plate 20), xiv, 59-60
Eskimos, conditions of life, xv, 123-4;
customs concerning dead, 338;
ideas of future life, xv, 333, 335;
kayaks of, 264 (fig.);
language lacking in abstract words, 144;
leadership among, 363;
meat eating by, ix, 284, 309;
polar bear catching by, xv, 224-5;
reindeer uses, xii, 320;
weapons of, xv, 209 (fig.), 210-12

Esophagus, functions and connections, ix, 230, 231;
heartburn in, 232;
operations of, xi, 37-9
Esparto Grass, v, 292
Espy, James P., i, 215, 345
Essential Oils, viii, 251-2, 336, 349
Esters, viii, 221, 245, 248, 376

Estuaries, formation of, iii, 37, xiv, 255, 256

Eta Argus, ii, 324
Eternity, real meaning, xi, 196
Ethane, derivatives, viii, 210

Ether, composition and properties, viii, 216-18, 376;
density of, iv, 113;
explosibility, viii, 62;
refrigeration by, iv, 174;
use as anesthetic, discovery of, x, 123-5, xvi, 185

Ether of Space (see Æther)
Ether Structure, viii, 217, 224
Ethyl, defined, viii, 376;
derivatives, 210
Ethyl Acetate, viii, 221
Etna, Mount, xiv, 100, 225, 316-17;
flashing arcs, i, 194;
water from eruption, iii, 107
Etruscans, vase decorations of, xv, 251
Eucalyptus Tree, xiii, 358;
fertilization of, xii, 266-7;
used in draining swamps, xiv, 379
Euclid, ii, 29, xvi, 81, 89, 95
Eudoxus, ii, 31, 300
Eugenics, x, 235-6, xvi, 157, 158
Euler, scientific work of, ii, 15, xvi, 125
Euphrates River, union with Tigris, xiv, 185
Europe, aeroplane routes, i, 44-5;
after-summers, 362;
Alpine invasions, xvi, 49;
ancient animals, xii, 275, 310, 359;
animals (carnivora), 336, 340, 348, 349, 350, 355, 356;
animals, (herbivora), 307, 317, 318, 329, 330-1;
aristocracies of, xv, 377;

Asiatic invasions, xiv, 74-5, 362, xv, 138-9, xvi, 141;
beet sugar production, xiii, 216;
birds of, xii, 255, 261, 262, 263, 266, 268-9;

Black Death in, x, 163-4;
cave period in, xiv, 148-9;
civilization in northern, 359;
climate of, 346-7, 359;
coast, western, 249;
coffee introduction, xiii, 232;
continental slope, xiv, 287;
cretinism in, x, 350;
Cro-Magnons in, xv, 99, 102, xvi, 50;
dowry system in, xv, 285;
drainage systems, xiv, 190;
earthquake belt, 332;
forests, 375-6, 377-8, 380-1;
former connection with America, 290;
geological history, iii, 180, 198, 216, 235-6;
glacial topography, xiv, 3, 30, 43, 61-2, 200;
gunpowder introduction, xvi, 101;
hail prevention devices, i, 340-3;

Ice Age in, iii, 62, 236-7, 239, 240, xv, 74, 75, 76, 102;
languages of, 161, 162;
map discrepancies, xiv, 10;
mediæval astronomy in, ii, 39-41;
meteorological statistics, i, 203;
monkeys of, xii, 378;
moor fires, i, 56;
mussel-eating in, xii, 65;
Nordic invasion, xvi, 50;
nutmeg introduction, xiii, 261;
paper introduction, v, 290;
paper making, 292;
plains of, xiv, 217;
population increase, xv, 27;
potato in, xiii, 218;
primitive man types found in, xv, 88, 92-102;
rainfall distribution, xiv, 352;
rainfall stations, i, 79;
revival of learning (see Renaissance);
rice in, xiii, 214;
rodents of, xii, 287, 288;
snails of, 69, 70;
snakes of, 218, 220, 231;
snow removal in cities, i, 117;
sugar introduction, xiii, 215;
syphilis in, x, 60;
tea introduced, xiii, 228;
telegraph systems, vii, 108;
tobacco introduced, xiii, 256;
trees of, xiv, 363, 375-6;
vegetables and fruits originating in, xiii, 222-7;
volcanic belts, xiv, 316-17;
weather observations, i, 217-18;
windmills, 37

European Races, classification and history, xvi, 48-50

Europeans, comparative measurements of, xv, 57;
hair of, 38;
northern and southern, color of, 37
European Sleeping Sickness, x, 301-2
Europium, symbol and atomic weight, viii, 383

Eustachian Tube, ix, 101 (fig.), 102, xi, 101;
adenoid effects on, x, 341-2;
deafness from closing of, ix, 103-4;
discovery, xvi, 82
Eutheria, xii, 271, 273-4, 281

Evaporation, body heat regulation by, i, 317, 318, ix, 316, 317;
by trees, xiv, 377-8, 378-9, 379;
(see also Transpiration);
cooling by, iv, 174, viii, 69, ix, 316;
electricity, caused by, vii, 212;
ice made by, v, 349-50;
measurement of, i, 88-9;
of liquids, iv, 167;
of terrestrial waters, xiv, 135;
water table affected by, 136
Evaporimeter (see Aumometers)
Everglades, Florida, draining of, v, 255
Evergreen Trees, deciduous, xiv, 370, 371;
in landscape gardening, xiii, 269, 270, 271
(See also Conifers)
Evesham Experiments, vii, 352

Evil Spirits, savage belief in, xv, 234, 304-5, 336, 339-40, 348, 352

Evolution, animals the main proof of, iii, 259, 260;

Buffon on, xvi, 139-40;
climatic, iii, 174;
Darwinian theory, x, 135, 136, xvi, 149-52;
Greek theories, 78-9, 139;
human, xv, 26-31, xvi, 47;
laws of, xv, 15-25, 381-2;
laws and goal of, xiii, 325-36;
Le Conte on, iii, 164;
social, xv, 29-31, 382, 383-4;
universality of, ii, 366, xv, 29, xvi, 152;
Wolff's theory, xvi, 118
Exaggeration of Parts, iii, 277
Excavating, air pressures in, v, 120;
through quicksands, 115-18, 123;
under river-beds, 121-4;
with water jets, 88
Excavating Machinery, v, 252-9;
for swampy ground, 216

Excitement, blood changes in, ix, 293, xi, 137, 138;
insomnia from, ix, 219;
pain and, xi, 119;
recovery period, 21
Exclusive Inheritance, x, 230-1
Exercise, effects, needs and rules, x, 303-6;
effects on breathing, ix, 256, 258;
effects on heart rate, 168-9, 207, 208-9, 261-2, x, 334;
effect on lymphatics, ix, 223;
effects on sweat glands, 169, 315-16;
for constipation, 251, x, 317;
heat produced by,
270, 306;
obesity and, 273-4, 275;
oxygen consumption in, ix, 261;
psychological importance, xi, 339, 371-2;
pulse rate after, x, 334;
tuberculosis preventative, 292;
violent, albuminuria from, 345
Exfoliation, iii, 24, 378
Exhaust, of engines, v, 164-5
Exhaust Fans, vii, 86
Exhaustion, kinetic theory, xi, 59-60;
mental and physical, 135-6;
nervous system in, 274;
pain in, 119;
unlike sleep, 286
Exoskeleton, xii, 127

Expansion, by heat, iv, 134-5, 138, 140, 145, 151, v, 71, viii, 25, 107;
coefficient of, iv, 145;
cooling by, i, 30, 90, iv, 188, 191-2, vii, 323, viii, 68;
of fused quartz, vii, 311-12;
of water and other substances on solidifying, iv, 149-51, viii, 38

Experience, ability to profit by, ix, 139-40, 152-3;
accumulation and results, xi, 33;
contradictions of, 11;
learning and, viii, 269;
learning by, in man and animals, xv, 66;
psychology science of, xi, 10-11;
sensations as, 68;
subconscious storing of, 47;
Sylvius's test of truth, x, 69
Explanations, slower than events, xi, 210
Exploration Drilling, v, 262-5
Exploratory Laparotomy, x, 147
Explosions, boiler (see Boiler Explosions);
cause of detonations, vii, 211;
chemical and physical processes, viii, 61-3;
dust, i, 63;
gunpowder, viii, 62, 145;
hydrogen in air, 33, 36, 62;
speed of sound in, i, 187
Explosives, viii, 63, 260-2;
detonation, 262;
history of development, xvi, 163;
nitrogen compounds in, viii, 66, 71-2, 74, 75, 237, 253, xiv, 66;
nitrogen waste in, viii, 345-6;
sulphuric acid in, 80;
weather making by, i, 335-9
Exposure (outcrop), iii, 381
Extemporaneous Speeches, xi, 245

Extension, perception of, xi, 166, 171-2, 183-9

Extensor Muscles, ix, 76-7, xi, 54, 166
Exteroceptive Senses, xi, 63
Extrusive Rocks, xiv, 105
Eye-and-ear Method (astronomy), xi, 155
Eyeglasses, benefits of, iv, 51
(see also Glasses)
Eye-mindedness, xi, 222
Eye of the Storm, i, 136, 372
Eyes, vi, 270-3, ix, 109-11, xi, 83-97;
abuse of, mental effects, 373-4;
color, inheritance of, ix, 335-6;
color in different races, xv, 37, xvi, 48, 49, 50;
color perception by, ix, 116-17;
color perception limits, iv, 360-1;
comparable with camera, ix, 108;
connection with brain, 124, 142;
controlling nerves, xi, 30;
depth perception by, ix, 120;
diseases and defects, 112-14;
distance of distinct vision, iv, 342, 343;
distance perception by, ix, 118-19;
double images, xi, 175-81;
fatigue from, 279;
fear effects, 132;
fixation, how learned, 39-40;
inflammation due to lack of vitamines, x, 260;
in infants, ix, 350, 351, xi, 39, xv, 61;
in sleep, xi, 282, 283, 286;
muscles around, ix, 77;
of various animal forms, xii, 67, 101-2, 138-9, 205-6, 209;
origin, xi, 109;
persistence of vision, iv, 346-7;
position in attention, xi, 232;
pupil size, iv, 343;
receptor organs, xi, 30, 62;
regulation to light, x, 254;
sensibility to light waves, iv, 360;
smooth muscles of, ix, 161-2;
soul in, savage idea of, xv, 330-1;
space perception by, xi, 169-70, 171-2, 173, 174-83, 186-90;
winking and watering of, 19, 23, 63
(see also Sight, Vision)
Eye Sockets, ix, 62
Eyestrain, ix, 113, 114, 239;
Behan on, xi, 374
Eyra, xii, 364
Fabre, J. H., xvi, 143-4
Fabrics, making of, v, 268-88;
manufacturing processes, viii, 256;
Philippine fiber, xiii, 236, 239;
warmth of different, ix, 311-12, x, 309
Fabry, Wilhelm, x, 78-9
Face, anthropological measurements, xv, 43-5;
brain case and, 43, 62;
in infants, ix, 345;
pallor and flushing of, 161, 165, 166;
brain power expressed in, xv, 39, 63-4;
color in different lights, iv, 364-5;
painting of, xv, 256
Facial Angle, xv, 44-5
Facial Expressions, xv, 63-4;
dejection and, xi, 337, 339;
man's trained control, 82, 350-1;
smell and, 82;
smiling, 357;
taste and, 74, 75, 76;
tone of voice and, xv, 144
Factor Differences, xiii, 330, 331-2
Factories, fatigue reduction, xi, 277;
importance of conditions, 361-2;
instruction of beginners, 363-5;
lighting importance, 361;
rest periods, 363;
warm floors, importance of, ix, 320

(see also Industrial Plants, Industrial Psychology)

Factory System, beginning of, x, 244;
occupational diseases in, 245
Fahrenheit, Daniel Gabriel, iv, 135-6
Fahrenheit Thermometer, i, 73, viii, 27;
compared with other scales, iv, 137, 141, viii, 27, 384;
invention, i, 69;
scale, how prepared, iv, 135-6, 137
Fainting, cause and relief, ix, 217;
due to weakness, x, 89;
low blood pressure in, 336

Fairmont, W. Va., deep well at, iii, 120, v, 265

Faith Healing, Barton on, x, 76;
effectiveness, xi, 374
Falcons, xii, 260, 261;
hunting with, xv, 223
Falkland Islands, groundsel of, xiii, 345

Falling Bodies, Galileo's studies of, iv, 19, 28, 97;
laws of, 96-7, xvi, 31-3;
velocity of, ii, 64, iv, 65;
velocity on sun and earth, ii, 168
Falling Stars (see Meteors, Meteorites)
Fall Line, xiv, 28, 214
Fallopius, x, 51, 53
Fallowing, viii, 341-2
Fall Winds, i, 132-3, 372
False Cirrus, i, 102, 104, 372
False Coral, xii, 47

Family, origin and evolution of the, xv, 273, 278-85, 360-1, 362

Fancy, pictures of, xi, 202

Fanning, benefits of, ix, 316-17

Farad, electric capacity unit, iv, 284, vii, 368

Faraday, chemical work, xvi, 160, 162, 163;
discovery of anesthetics, 185;
dynamo invention, 189;
electrical work, vi, 16, 21, 22-3, 50;
farad named after, iv, 284;
metallurgical work, xvi, 174;
on lines of force, iv, 252;
on philosophers, x, 376;
suggestion of fourth state of matter, xvi, 193

Faradic Currents, vii, 243, 248-9

Fargo, N. D., region, iii, 34

Farmers, ancient and recent methods, v, 239-40;
motor machines, 214;
past injustice and hardships, vii, 220-1;
small, and machinery, v, 249-50
Farms, cost of horse work, vii, 224-6;
electricity on, iv, 10, vii, 220-34;
migration of boys from, 221;
motor machines on, v, 214, 215-18
Far-sightedness, ix, 112-13, xi, 85
Fata Morgana, i, 172, 372
Fatigue, xi, 268-80;
adrenalin effects, 137;
cure for, x, 247-8;
disorders and diseases due to, 246-9;
from muscles, xi, 124;
from posture, ix, 83, 84;
habit and, xi, 253;
insomnia from, 289;
mental and physical, relations, x, 247, xi, 135-6;
mental effects, 13;
mental effects illustrated, xvi, 18;
muscular, cause and effects, ix, 80-1;
nervous, 137-8;
no sense organs of, 91;
physical effects of, x, 246-7;
rest periods and, xi, 363;
retardation of impulses in, 20;
sleep in relation to, ix, 219;
smooth muscles free from, 84-5;
stimulation to change, xi, 338-9;
suggestibility in, 307
Fatness, (obesity), x, 272-5;
adipose tissues in, ix, 298;
reduction of, 301-2

Fats, amount in daily diets, viii, 366-7, ix, 300-1;
animal, viii, 246, 348, 349, 350, x, 260;
animal, vitamines in, ix, 33;
calories in, viii, 361, x, 269;
composition, viii, 221, 245, 247, 335-6, 376;
digestion and utilization, 356, 357, 359, ix, 242-3, 244-5, 289-90, 294, 298-9, x, 326, 330;
extraction of, viii, 246;
food value and requirements, 335, 336, 362, 363, ix, 33, 300-1, x, 256, 260-2, 268, 269, 271;
identification of, viii, 310;
indigestibleness of, ix, 286;
in human body, viii, 348, 349;
lipins, 350-1;
liquid and solid, 232, 244, 247
(see also Oils);
metabolism of, x, 270;
molecular structure, viii, 217-18;
not antigens, x, 205;
preserving of, viii, 371;
skin excretions, x, 310;
soap effects on, viii, 141-2;
soap made of, 141, 221, 246;
tastelessness, 366;
uses, 246-7;
vegetable, 246, 335-6, 349, 350;
vegetable, lack of vitamines in, x, 259, 260-1, 262

Fatty Acids viii, 220;
butter percentage, 245, 364;
candles made from, 247;
in fats and oils, 221, 244, 245;
soap made from, 221, 246

Faults, Faulting, iii, 86-92, 378, xiv, 37-8, 114-28;
coasts formed by, 264;
earthquakes and, iii, 87, 90, 93, 94-6, 97, 98, xiv, 39, 115, 128, 334-5, 339-41;
greatest displacement, 39;
hot springs in relation to, 143;
lakes formed by, iii, 151, 152, 153;
mountains formed by, 138-9, xiv, 226, 229, 230

Fault Scarps, iii, 378, xiv, 38;
denudation of, 115-16;
persistency of, 122, 123, 124
Fault Valleys, xiv, 127-8

Fear, cause and accompaniments of, ix, 153, 166, xi, 131-3, 136, 138;
dominant human impulse, xv, 185;
dreams from, xi, 293, 294, 299-300, 301-2;
expression of, in animals, xv, 64;
in various sentiments, xi, 146, 147, 148;
pain deadened by, 120;
subconscious processes and, 212-13, 214
Feathers, of birds, xii, 243-7

Feeble-mindedness, inheritance of, x, 234, 235-6;
reflex action in, xi, 36
Feelings, brain processes in, ix, 154;
classes of, 153-4;
essentials of, xi, 25;
expression of, xv, 143;
motor response and, xi, 43 (see Consciousness, Emotions, Sensations)

Feet, bones of, ix, 68-9, 70 (fig.);
care of, x, 312;
Chinese women's, xv, 260, 261 (fig.);
cold or warmth felt in, ix, 320, 322;
custom of covering, xv, 254;
equal size of, ix, 170;
mental impairment by troubles with, xi, 373;
of ape and men, compared, iii, 301 (fig.), xv, 57, 60-1;
of infants, 61;
of Tertiary mammals, iii, 298, 299-300;
proper shoeing, ix, 69-70, x, 306;
relative lengths, xv, 57;
soles of, nerve connections, ix, 132, 135;
uses of, by men and monkeys, xv, 60-1;
wetting of, and colds, x, 239, 306, 341
Feldspar, iii, 308, 328-9;
chemical composition, viii, 90, 193;
clay from, iii, 25, 27, 28, 373;
disintegration, viii, 194;
potash in, 201
Felt, making of, v, 289
Fer-de-lance, xii, 234
Ferdinand II of Tuscany, i, 69, 213
Fergusson, William, x, 130
Fermat, Pierre de, xvi, 105, 114, 119
Fermentation, alcoholic, viii, 248-9;
of sewage, 328;
of sugars, 225, 227;
on what dependent, xiii, 66, 71;

Pasteur's studies in, x, 137, 138-9, 141, 143 (see Alcoholic Fermentation)

Ferments, viii, 357, 376;
as catalyzers, 103
Ferns, xiii, 63-6;
classification, iii, 251;
cycad-like, xiii, 309;
evolution, iii, 252, 254, 256, xiii, 303, 317;
fossils, iii, 272 (Pl. 15), xiii, 324;
in tropical forests, xiv, 368;
mosses and, xiii, 69;
number of species, 323;
power of roots, 19;
reproductive processes, 155-60
Ferrel's Law, i, 124-5
Ferrets, xii, 349
Ferric Compounds, viii, 161
Ferrite, viii, 160, 273
Ferrous Compounds, viii, 161;
action of oxygen on, 194
Fertilization of Plants, xiii, 118-65;
devices to insure, 48-53;
of yucca plant, xvi, 152-3
(see also Cross Fertilization)
Fertilizers, viii, 278-80, 342-6;
ammonium, 147;
garbage, 330, 343;
natural, 327, 342-4;
natural, in southern China, xiv, 73;
nitrogen, i, 34, viii, 72, 74, 75, 137, 280, 345-6, xiv, 66;
phosphate, viii, 89, 153, 279-80, 344-5, xiv, 67, 68;
potassium, viii, 134, 146, 278-9, 344;
potash, xiv, 67-8;
primitive knowledge of, xv, 202
Festoon Clouds, i, 104, 372
Fetal Anlage, x, 120
Fetishes, xv, 348-9

Fevers, cause, temperature, and treatment, ix, 317-19;
cooling of skin in, iv, 174;
explanation of phenomena, x, 214;
heart rate in, 334;
improvement of treatment, xvi, 184-5;
inanition in, x, 276;
racial immunity and susceptibility to, xv, 50, 51;

Sydenham's treatment of, x, 73;
use of antipyretics in, 381
Fibers, cellulose, viii, 254-6;
sources, uses, and kinds, xiii, 235-45
Fibrin, ix, 180

Fields, electrostatic and magnetic, vii, 368 (see Electrostatic Fields, Magnetic Fields)

Field Strength or Intensity, vii, 368, 370
Figs, for constipation, ix, 251;
origin, xiii, 225
Fig Trees, antiquity of species, xiii, 324-5;
of Bahamas, 18;
of Brazil, 365;
of India (illus.), 16;
of West Indies, 21
Filled Space, xi, 187
Filled Time, xi, 194
Filterable Viruses, x, 200
Final Common Path, xi, 22-3;
in acquired tastes, 73;
in association of ideas, 199;
in attention, 230;
preoccupation of, 119, 120, 121
Finches, coloring of, xii, 245-6
Fingal's Cave, jointed rocks in, xiv, 129
Fingers, bones of, ix, 67, 68, (fig.);
curling of, in infants, ix, 349;
flexed position, xi, 42-3;
muscles for operating, ix, 76;
of men and apes, xv, 60
Finland, coast of, xiv, 247, 259;
lakes of, 200
Finland, Gulf of, salinity, xiv, 296
Fiords, (see Fjords)

Fire, Civilization in relation to, ix, 308, 309, xv, 229;
discovery of, v, 349;
possibility of life in, ii, 251;
production and sources, viii, 89, xv, 229-32;
production by air compression, v, 128;
production of, by friction, iv, 48-9;
religious associations of, xv, 234
"Fire Animal," xii, 20
Firearms, v, 361-8, 379;
ignition systems, viii, 145
Fire Balloons, v, 223
Fire Damp, iii, 354
Fire Engine, Ericsson's steam, v, 378;
Hero's, xvi, 92-3

Fire Extinguishers, carbon tetrachloride in, v, 212;
chemical and electric, vi, 101, 102
Fireflies, xii, 124;
as ignis fatuus, i, 346;
light of, vi, 268

Fire Hazard, electricity and, vii, 51-2, 223, 224;
in rural districts, 231;
reduced by lightning rods, i, 156
Fire Proof Type of Construction, vii, 55
Fire Pumps, v, 114
Fire Underwriters, Board of, vii, 53-4

Fires, caused by overloaded circuits, vii, 34;
cause of "spalling" in, iii, 24;
crowd psychology at, xi, 327-8;
dust from, i, 56-7;
extinguishing of, viii, 56-7;
prairie, xiii, 374, 375;
rain control by, i, 345;
records in tree rings, xiii, 25
Fire-Weather Warnings, i, 240
Fireweed, seed dispersal, xiii, 343-4
Fir Trees, dominance in north, xiii, 350;
forests of U. S., 367-8;
in landscaping, 270-1
(see also Conifers)
Fish, as food, ix, 24;
calories in, 299;
food value, viii, 362-3;
vitamines in, x, 262
Fishes, Age of, iii, 20, 21, 283, xv, 71;
anatomy and physiology of, xii, 132-6;
bony, 151-3;
breeding habits, 140-1;
carelessness of offspring, xv, 275;
cartilage skeletons of lowest, ix, 58;
catching of, by savages, xv, 227-8;
catching of, with cormorants, 223-4;
classification, iii, 260, xii, 142;
deep sea (see Deep Sea);
eggs, 140-1, 155, xv, 21, xvi, 116;
evolution, iii, 282-5;
food of, ix, 24;
intelligence in, xii, 139-40;
leeches and, 56;
migrations in relation to plankton, xvi, 147-8;
modern, xii, 154-66;
number of species, xvi, 146-7;
of oceanic islands, xiv, 278;
oxygen supply of, viii, 35, ix, 182;
rate of increase in, xv, 20;
regeneration in, xii, 170;
reproduction in, 140-1;
sense organs, 137-9;
"showers," of, i, 355;
temperature variations, 317;
temperature variations, effects, ix, 78
Fish-eye Views, iv, 374
Fishhawks, xii, 260
Fish Patrol, Aerial, i, 48
Fission, xii, 26
Fissures, defined, iii, 378;
ore deposits in, viii, 199
Fissure Springs, xiv, 138, 152
Fitch, John, steamboat, v, 189
FitzRoy, Admiral Robert, i, 224-5, 282, 363
Fiume, importance to Jugoslavs, xiv, 268, 306
Fixation (sight), how we learn, xi, 39-40
Fixed Stars, ancient idea of, ii, 350;
motions of, 46, 86-7, 121-2, 304-5 (see Stars)

Fjords, Fjord Coasts, xiv, 258-62;
Norwegian, formation of, iii, 79;
Norwegian, frost smoke, i, 95
Flagellate Cells, xii, 30-1
Flame, viii, 57-61;
colors as metal tests, 133, 134, 144, 289, 301;
heat production by, iv, 138, 144
Flamingos, xii, 256
Flammarion, books on Mars, ii, 238;
on curious showers, i, 355;
on lightning pranks, 153-4
Flamsteed, astronomer, xvi, 124;
star numbering, ii, 302-3
Flannel, heat conductivity, iv, 179
Flannelette, x, 308
Flashboards, vii, 40
Flash Boiler, v, 213
Flashes, electric, vi, 91;
extinguished by electromagnets, 102
Flashing Arcs, i, 194, 372
Flatfish, eyes of, xii, 138
Flatulence, sleeplessness from, ix, 219
Flatworms, xii, 18, 44-5
Flavors, ix, 95, 97;
chemistry of, viii, 251-2;
food value, 366, ix, 98, 240, 242;
in plants, viii, 349;
perception of, ix, 97-8
Flax, retting of, xiii, 243;
spinning of, in ancient Egypt, xv, 243, 244 (fig.)

Flax Plant, products and origin, xiii, 235, 244, xiv, 382

Flesh-eating Animals, as food, ix, 24;
bile color in, 275;
intestine length in, 246;
protein surplus in, 284-5
Flexner, medical work of, x, 200, 218, 302
Flexor Muscles, ix, 76-7;
strength, xi, 41, 43;
withdrawing reactions by, 54
Flies, xii, 120;
appearance in Jurassic, 104;
buzzing of, 103;
claws of, 102-3;
evolution and varieties, 104-6;
plant fertilizers, xiii, 131-3;
typhoid fever spread by, x, 287, 288;
wings of, xii, 103
Flight, bodily preparations for, ix, 166;
instinct of, xi, 55, 132, 136
Flint, iii, 13, 337;
fire production by, iv, 48;
flaking of, xv, 103, 104, 107 (fig.), 109
Flint and Steel, xv, 232

Flint Implements, ancient, xv, 79, 81, 82, 87, 104, 105, 109

Flintlock, viii, 145, xv, 217, 218 (fig.)
Floating Bodies, v, 95, 195-6;
laws of, iv, 103-4, 107
Flood Lighting, vi, 283
Flood Plains, iii, 379, xiv, 53;
alluvial soils of, 70, 71;
embankments and slopes, 161-2;
illustration, iii, 80, (Pl. 4);
in old and new areas, 33, 34;
plant societies of, xiv, 372
Floods, power of, iii, 31;
rainfall and, i, 110-11
Flood Warnings, i, 240
Floors, warm, importance of, ix, 320
Flora, defined, xiv, 363
Florida, alligators of, xii, 197;
coal forming conditions, iii, 199;
coasts of, xiv, 251;
co-, xii, 40, 42;
crocodiles of, 198;
frosts in, xiv, 370;
serpula quina rock, viii, 152;
coral reefs, tubes, xii, 55;
shad fishing in, 155;
snakes of, 226, 236;
tarpon of, 154;
wolves of, 341;
youthful topography and drainage system, xiv, 157-8, 199-200, 201

Florissant, Colorado, insect remains at, iii, 279-80

Flour, calories in, ix, 299;
Graham, ix, 35;
vitamines in various kinds of, x, 262, 267
Flourens, Dr., x, 126, xvi, 185

Flowering Plants, beginnings and development, iii, 20, 252, 255, 256-7, xiii, 318-19;
classification, 60-1, 173-81;
classification place, iii, 251;
culmination of plant life, xiii, 73-4;
description of parts, 15-62;
families and relationships, 168-207;
in relation to animal life, iii, 257;
none in earliest ages, xiii, 303;
number of species, 168, 319, 323;
origin of present, 323-5;
reproductive methods, 117-54, 167

Flowerless Plants, iii, 251, xiii, 13, 14, 43;
evolution, iii, 252, 253;
ferns, xiii, 63-6;
nonvascular, 66-73;
numbers, 168;
reproduction, 62-4, 154-65
(see also Cryptogams)

Flowers, annuals and perennials, (tables), xiii, 289-97;
coloring and fragrance, 124-5;
colors in various shrubs, (table), 274-88;
family groups determined by, 184;
fertilization devices, 48-51, 117, 123-48;
fertilization the climax of life, 152;
highly cultivated, 51;
largest, 363-4;
love in, 115;
matings of, remarks, 116-17;
male and female, 46-7;
motion pictures of growth of, iv, 348;
of monocotyledons and dicotyledons, xiii, 176, 178, 189-90;
parts of, 43-6;
purpose, 46, 52-3, 61;
various forms and colors, 47-53, 181-207
Flu, (influenza), x, 294-5
Fluctuating Variations, xiii, 328
Flue Gases, electric clearing, vii, 216, 343

Fluids, distinguished by pressure and diffusibility, iv, 22-3;
elasticity of, 158;
osmosis, xiii, 90-1 (see Osmosis);
pressure of, iv, 116-19;
pressure on moving inclined planes, i, 287-8;
principles applicable to, iv, 126 (see Gases, Liquids)

Flukes, sea, xii, 44
Fluorescence, iv, 379-80;
produced by X-rays, 318, 320

Fluorescent Screen, iv, 320, vii, 254-5, viii, 184

Fluorine, a halogen, viii, 18, 84, 85, 87;
atomic weight and symbol, 383;
in apatite, 193;
in tissues, 354
Fluorite, iii, 329-30
Fluoroscope, iv, 320
Flushing, of skin, ix, 161, 162, 163, 215
Flute, development of, xv, 316, 317 (fig.);
Egyptian, 314 (fig.)
Fluxing, of ores, viii, 270
Fly-Catcher (plant), xiii, 40-1
Flying Dragons, xii, 206
Flying Fish, order of, xii, 163;
wings of, 134
Flying Mice, xii, 278

Flying Reptiles, iii, 293-4, 320 (Pl. 18), xii, 202, 203 (fig.)

Foci of Infection, x, 198-9, 218-26
Focus, defined, iv, 335;
of cameras, ix, 108-9;
of eye, 110-11;
of lenses, iv, 338;
real and virtual, 335
Foehn Sickness, i, 328
Foehn Wall, i, 105, 372
Foehn Winds, i, 133, 372
Fog, i, 93-7, 372;
aviation effects, 300-2;
costs and dispersion, 94, 302;
dust nuclei, x, 62, viii, 304;
dry (see Dry Fog);
light diffraction by, i, 183, 185;
rime formed from, 121-2;
sound transmission by, 190
Fog Bows, i, 176, 372
Fog Drip, i, 351, 353, 372
Fog Hiccups, i, 195
Fog Signals, audibility, i, 189-91;
sirens, iv, 205

Folded Mountains, iii, 131-8, 190-1, xiv, 36-7, 226-34;
ridges in, 93-4, 95-6

Folding of Rocks, iii, 84-6, 349 (fig.), 379, xiv, 36;
theories of process, 231-2;
topography made by, 38, 93-9
Food, Foods, adulteration of, viii, 370-1;
amount consumed, 366-7;
artificially prepared, x, 257, 267-8;
benzenes and paraffins as, viii, 234;
calories in various, 361, ix, 299, x, 269;
calories, valuation in, iv, 48;
chemistry of, viii, 348-72;
children's, x, 314-15;
cold storage of, iv, 187, 8;
constituents all in air and water, i, 25;
cooking of, viii, 367-9, x, 263, 266 (see Cooking);
deficiency of, diseases from, x, 255-69, 276;
digestion and utilization, viii, 356-9, ix, 226-52, 277-304, x, 268-71, 319-20;
fat-producing, x, 273;
infants', ix, 346-7;
kinds needed during exertion, xi, 278;
methods of obtaining, importance of, xv, 186-7;
nitrogen importance, viii, 66, 229;
of animals and plants, 349, 350, xii, 15;
procuring of, by animals, ix, 18-20
(see also Chemotaxis);
requirements, viii, 362-7, 369-70, x, 255-68, 278-9;
selection of, viii, 369, ix, 300-1;
sources of, 24-30;
storing of, by animals, xii, 292-3;
taste and smell of, ix, 94-5, 97-8, 240, 241-2;
use of, for energy development, 15-16, 24, 36-40, 289-301;
use of, for growth, 31-4, 38-9, 286-9;
use of, for tissue repair, 34-6, 278-84
(see also Diet, Nutrition)
Food-poisoning, indigestion from, ix, 239
Food Plants, xiii, 209-27
Food Preserving, viii, 371-2;
chilling and refrigeration, v, 346, 353;
X-ray sterilizing, vii, 257

Food Supply, its making by plants, xiii, 77-84, 95, 96;
of tropics, 359
"Fool's Gold," iii, 335
Foot Candle, iv, 352, vii, 368
Foot-pound, iv, 79, vi, 82;
erg and calorie equivalents, vii, 382;
equivalent in watt-hours, iv, 312;
heat equivalent, v, 350-1

Foot-pound-second System, iv, 46 (see British System)

Foot-poundal, unit of work, iv, 79
Foraminifers, iii, 54, 259, 261, 266;
in pelagic plankton, xii, 17-18
Force (mechanics), iv, 33-4, 41;
centrifugal and centripetal, 71-5;
defined, v, 182-3;
law of, in machines, iv, 90, 92;
Leibnitz's theory, xvi, 117;
magnetic, vii, 369;
measurement and units of, iv, 46, 58, 63-5, 69-70;
momentum and, 66-7;
motion and, 56-69, 71-2, 78;
Newton's and Huygens' studies of, 11;
primary forms of, 25;
static and kinetic measures of, 33;
work in relation to, 37-8, 78-9
Force Pump, v, 113-14

Forces, composition and resolution of, iv, 75-7;
parallel, 99;
parallelogram of, v, 184-6

Forecasts, i, 224 (see Weather Forecasts, Crop Forecasts)

Foreign Languages, advantages of learning, xv, 146;
jabbering sound, xi, 103;
difficulty of learning, 201

Foreign Plants, importation forbidden, xiii, 272, 289;
introduction aided by phenology, i, 254
Foreign Trade, meteorology in, i, 268-9
Forest Fires, aeroplane lookouts, i, 48-9;
dust from, 56-7;
losses by, xiii, 371-2;
number and losses, i, 48-9;
rain and, 333-4;
records in tree rings, xiii, 25

Forests, ancient, iii, 252, 253-4, xiii, 10, 307-10, 312, 313;
branching of trees in, 86;
burial by sand dunes, iii, 74;
climate affected by, xiv, 379;
climax, xiii, 370;
conservation of, xiv, 238-9, 382-3
(see also Conservation);
earthquakes in, 333;
European, 238-9;
grasslands and, xiii, 348-9, 368 (illus), 374-5, xiv, 380-1;
importance to industry, vi, 366;
leaving of trees in, xiii, 86-7;
migration of, xiv, 375-6;
mountain, 239-9;
northern limit, 375;
park, 374;
products, 382-3;
rainfall and, xiii, 372, xiv, 377-8;
soil protection by, 42, 379;
squirrel planting of, xiii, 340;
temperate, 366-73, 272 (illus), xiv, 370-1;
trees in American and European, 363, 375-6;
tropical, xiii, 358-66, xiv, 366-70;
types of, xiii, 357-8;
United States, xiv, 239, 372-4;
United States national, xiii, 371-2;
water supply and, 371-2, 9, xiv, 239
Forgetting, process of, xi, 209;
rate of, 216
Forked Lightning, vii, 205, 206-11;
sinuous character, i, 146
Form, athletic, ix, 159
Formaldehyde, viii, 219, 333, 335, 372
Formic Acid, viii, 220
Formosa, rice paper tree of, xiii, 214;
continental island, xiv, 274
Form-wound Coils, vi, 202, 223, 245
Fortin's Barometer, iv, 119-20
Fossane, xii, 353
Fossil Botany, xvi, 167
Fossil Record, extent, iii, 13-14;
imperfectness, xiii, 302-3, 306-7, 323-4, 325;
of various geological strata, iii, 165, 174, 179, 180, 263-5, 268

Fossils, defined, iii, 13, 379;
formation, 15-17;
formation of plant, xiii, 301-2;
former views of, iii, 14-15;
geological strata determined by, 15, 18-19, xvi, 126, 169;
of earliest animals, iii, 261-2, 263, 265-6;
of earliest birds, xii, 239-43;
of herbs and woody plants, xiii, 319, 324;
of sharks' teeth, xii, 142;
of water plants, xiii, 303;
of worms, iii, 270;
oldest known, 250;
some remarkable, 286-8, 291, 292, 295, xiii, 306, 347

Four-Cycle Engines, v, 159, vii, 123-4

Fourdrinier Paper Machine, v, 291, 295-8, 377

Four o'Clock (flower), colors in crosses, ix, 334, 336

Foussa, xii, 353, 354
Fowls, white meat of, xii, 247
Foxes, xii, 342-4;
excavators, xv, 206;
storing of food by, xii, 292
Fox Fire, i, 346
Fractional Distillation, i, 32, iv, 168
Fracto-Cumulus, i, 102
Fracto-Nimbus Clouds, i, 101
Fracto-Stratus Clouds, i, 102
Fractures, Pott's, x, 92;
X-ray locating of, vii, 254, 255, x, 185
France, aluminum production, iii, 369;
ancient fossils found in, 252, 263, xiii, 319;
botanical education, xvi, 22;
chalk deposits, iii, 266;
coasts, xiv, 46, 47, 257;
Cro-Magnons in, xv, 102;
early civilization of, xiv, 359;
first balloons, v, 219-21;
forestry in, xiv, 239, 382;
hail devices, i, 341, 342-3, 343-4;
harbors of north coast, xiv, 270-1;
invasions of, course taken, 92;
mistral winds, i, 133;
Northmen in, xiv, 261;
oyster culture in, xii, 62;
Paleolithic remains in, iii, 304-5;
rainfall of northern, i, 338;
river changes in, xiv, 184;
standard gun-manufacturing, v, 49;
tidal power plants, 176-7;
surgery made a profession, x, 104-5;
topography in World War, xiv, 86 (map), 88-93;
tuberculosis campaign in, x, 175-6

Franco, Peter, x, 57, xvi, 108

Franklin, Benjamin, cold season theory, i, 58-9;
climatic changes paper, 200-1;
electrical work, vi, 10-11, 13-16, xvi, 121, 188-9;
lightning experiments, i, 141, iv, 269-70, vi, 11, 14-16, vii, 204-5, xvi, 121;
lightning rods, vii, 218-19;
medical work of, x, 104;
meteorological work, xvi, 177;
on "magnetic sleep," 185;
single-fluid theory, vi, 11, 288
Franklinic Currents, vii, 245
Fraunhofer Lines, ii, 112, iv, 362, viii, 302
Frazer, Sir J. G., i, 334

Frederick Barbarossa, medical interest of, x, 38

Freeze, defined, i, 372
Freezing, expansion of water on, iv, 149-51;
heat production by, 161
Freezing Mixtures, iv, 175;
known to ancients, v, 349

Freezing Point, in various thermometers, i, 73, iv, 136, 137, 141, viii, 27;
of solutions, 299-301;
of various substances, iv, 173;
pressure effects on, 163-6
Freiberg, School of Mines, xvi, 126, 127
Freight Engines, modern, v, 210
French, in Alpine group, xvi, 49;
in America, xiv, 31, 191-2, 242, 310, 311

French Language, descent from Latin, xv, 160, 162

French Revolution, causes and results, xvi, 128;
crowds of, xi, 326;
metric measures adopted in, iv, 136;
results on cultural advance, x, 107
Frende, Gabriel, i, 244
Fresnel, light studies, xvi, 137
Freud, Sigmund, on dreams, x, 364;
on hysteria, 361;
psychoanalysis of, 363
Freudian School, work of, xi, 142
Friction, iv, 92-4, v, 203-7;
fire obtained by, viii, 89;
heat production by, iv, 48, 138;
in tubes, ix, 215

Frictional Electricity, iv, 257-8, 260, vi, 11, 12, 13, 286-7;
discovery, xvi, 122;
electron theory, vi, 122-3;
identical with other kinds, 23;
single fluid theory, 288
Frictional Machines, iv, 265, vii, 236, 245
Friction Matches, iv, 49, 138, viii, 88
Fried Foods, ix, 286
Frigate bird, xii, 253-4

Fright, physiological effects of, ix, 161, 165, 221, 240-1

Fringed Gentian, a biennial, xiii, 16;
corolla of, 44 (fig.)
Fringing Reefs, xii, 41, xiv, 263

Frisian Islands, coast destruction in, xiv, 46

Frogs, iii, 285, xii, 169, 174-6, 177-81;
evolution of, 167;
heart of, ix, 84;
regeneration in, xii, 170;
sense organs in, 169, 174;
"showers" of, i, 355;
temperature effects on, ix, 78-9, 306
Frostbite, x, 252
Frosts, i, 257-60, 373;
insurance, 270;
rock weathering by, iii, 24, xiv, 62, 75-7, 233

Frost Smoke, i, 95, 373
Fructose, viii, 226
Fruit, defined, xiii, 53-4;
development, 54-5;
dry and fleshy, 54-5;
family groups determined by, 184;
flavors due to esters, 221;
food value, 365, ix, 34, 300, x, 262, 266, 268, 273, 317;
in grasses and sedges, xiii, 179, 182;
purposes of, 61;
seed dispersal, 55-9
(see also Seed Dispersal);
sugar storage in, ix, 27-8
Fruit Trees, as index plants, i, 255-6;
frost danger points, 258
Fuels, future motor, viii, 209;
heat
measurement, 360-1;
our waste of, v, 172;
power from oxidation of, ix, 15-16, 24
Fuel Value, viii, 360-1
Fuji-san, Japan, xiv, 100, 320

Fujiyama, Japan, as observatory site, ii, 145, 149;
shadow in sky, i, 170
Fulgurites, i, 153, 373
Fuller Cells, vi, 137, 142-3
Fully, Lake, water drop, v, 81
Fulminating Mercury, viii, 262
Fulton, Robert, steamboat, v, 192, 377;
steam war vessel, 378;
submarine, 197-8
Functional Metabolism, ix, 39;
control of, 39-40, 77-8, 170;
daily amount in calories, 297;
food requirements dependent on, 295;
heat production by, 307;
no tissue wastage by, 282-3;
of glands, 159;
of muscle cells, 74, 77-9;
of nerve cells, 122-3;
of posture, 84;
of vital processes, 295-6
Fundamental Tones, iv, 213;
of bells, 222;
of organ pipes, 228-30;
of vibrating strings and rods, 223-4
Fundy, Bay of, tides, v, 175, xiv, 293
Fungi, xiii, 70-1;
in coal formation, 312;
luminous, i, 346;
reproductive processes, xiii, 164;
in rotten plants, 99;
species, 323;
spores in atmosphere, i, 61
Fungicides, viii, 77, 333
Funk, Casimer, x, 259
Furs, source of costly, xii, 346-51;
warmth of, iv, 178, ix, 311, x, 309
Furrows, of continental shelves, xiv, 287
Fusel Oil, viii, 214

Fuses, purpose and construction, vii, 34-7, 369;
inverse time features, 37, 39
Fusibility, of minerals, viii, 202, 384
Fusion, latent heat of, iv, 152, 160, 161;
table, 162
Fusions, of odors, xi, 81;
of tastes, 73;
of tones, 106;
of touch, 111
Future, a habit of thought, xi, 192;
predictions of, xv, 354, 355

Future Life, primitive conceptions of, xv, 332-6, 339, 340, 345, 358

Gadflies, xii, 120

Gadolinium, symbol and atomic weight, viii, 383

Gailey, James A., v, 383
Galactose, viii, 226
Galagos, xii, 375
Galapagos Islands, xiv, 276;
turtles of, xii, 187, 192
Galaxy, ii, 350-6;
as basis of star distribution, 350, 353, 354, 364-5;
globular clusters and the, 339, 343;
nebulæ and the, 363, 364-5;
solar system and, 353-4;
spectra of stars, 116;
star streams and, 346;
studies at Mt. Wilson, 158-9, 160;
type of stars, 122;
variable stars and, 327, 328, 330, 332
Galen, x, 28-31;
anatomical ideas disputed by Vesalius, 51, 52, 53;
arterial bleeding unknown to, 39;
authority in Middle Ages, 32, 34, 36, 37, 39, 41, 43, 51, 52;
classification of minds, xi, 152-3, 155;
classifying tendency of, x, 83;
Locke, on, 75;
medical works, xvi, 98;
on circulation of blood, x, 22, 62-3, 65-6;
on convulsions, fainting, etc., 89;
on occupational diseases, 244;
Paracelsus on, 47, 48;
revival of writings, 44, 45
Galena, iii, 330, 362, 363, 368
Galilee, Sea of, formation, iii, 156;
level, xiv, 121

Galileo, astronomical work, ii, 14, 53-6, iv, 27-8;
astronomical and other work, xvi, 103;
discoveries, ii, 83, 94, 96, 262;
falling bodies demonstration at Pisa, iv, 28, 97, 101;
medical advances due to, x, 67;
motion studies of, iv, 19, 28, 35, 61;
on Galaxy, ii, 351;
on Gilbert, xvi, 109;
on laws of motion, ii, 63;
on Mars, 227;
pendulum discovery, v, 63-5;
pendulum clocks suggested, 65;
studies of nebulæ, ii, 357;
telescopes, 12, 94, 95;
thermometer invention, i, 68, 69, x, 71;
Torricelli pupil of, iv, 114
Gall Bladder, inflammations of, x, 220, 224
Galley Worms, xii, 88-9
Gallium, discovery of, viii, 180;
symbol and atomic weight, 383
Gallon, cubic inches in, iv, 46
Galls, on plants, xii, 125;
on roots, xiii, 98
Gall Stones, ix, 276
Galton, Sir Francis, eugenic work, xvi, 157;
on ancestral heredity, x, 231;
on fatigue, xi, 275;
on sun's corona, ii, 222;
statistical methods, xvi, 153
Galvani, electrical work, vi, 16-17;
electrical work, xvi, 122, 189
Galvanic Batteries, vii, 369
Galvanic Cells, vii, 236, 241-2
Galvanic Currents, vii, 242, 244, 248
Galvanism, discovery, xvi, 122

Galvanized Iron, vii, 318-19, viii, 155-6, 273

Galvanometers, iv, 279, vii, 179, 369;
invention, vi, 23, 24
Galveston, harbor of, xiv, 269;
hurricanes, i, 136;
hurricane of 1900 and rebuilding, xiv, 302-3
Game Birds, xii, 261-3
Games, athletic, advantages from, x, 304
Gamma Rays, i, 143, viii, 185
Gamopetalae, xiii, 47, 190, 201-5
Ganges River, crocodiles of, xii, 201;
delta, iii, 32, xiv, 53;
erosion by, iii, 31;
furrow of, xiv, 287
Ganglia, of nerves, xi, 26
Gangue Minerals, viii, 199;
handling of, 269, 270
Gannets, xii, 253
Ganoids, iii, 283 (fig.), 284, xii, 152-3
Ganoid Scales, xii, 134
Garbage, as fertilizer, xv, 280, 343, 344;
disposal of, 330, 346
Garda, Lake, formation, iii, 146;
in rift valley, xiv, 123
Garden Plants, xiii, 267-97;
origin of, xiv, 382
Garfield, James A., speech of, xi, 323
Garnet Group, iii, 330
Gar Pikes, xii, 134, 152, 153
Garua, Peruvian fog, i, 95, 373
Gas Carbon, electrical conductivity, iv, 283
Gas Constant, iv, 142
Gas Engines, v, 155-6, 381;
efficiency, on what dependent, iv, 192;
ignition, vii, 369;
in submarines, vi, 239;
operation in automobile, vii, 123-33;
starting of, vi, 235
Gases, adiabatic change in, iv, 158-9;
atmospheric, i, 9-16;
Boyle's Law, iv, 125-6, 133, 143;
Boyle's and Mariotte's researches, xvi, 110;
buoyant effect, iv, 30;
Charles's Law, 140;
chemical properties, viii, 297-8;
combinations, Gay-Lussac's studies, xvi, 133;
compressibility variations, iv, 143;
condition at absolute zero, 142-3;
conversion of liquids into, 152-3, 173-4;
cooling by expansion, i, 30, 90;
critical temperature, 29, iv, 171-3;
diffusibility of, iv, 23, 131, viii, 22-3, 23, 108;
distinguished by pressure and diffusibility, iv, 22-3;
elasticity of, 158-9, 198;
electric discharges through, 54-5, vii, 216, 301-2;
electrolytic separation, 321-4;
electrical conductivity of, iv, 259;
expansion by heat, 135, 151;
expansion coefficient, 145;
flame due to burning, viii, 57;
gram-molecular volume, viii, 109;
heat absorption, 309;
heat convection in, iv, 178;
heat effects on, 139-40;
heat from compression, i, 90, v, 351;
heat non-conductivity, iv, 177, 178;
ignition, viii, 54;
interchanges of molecular energies, xvi, 134;
ionization of molecules, i, 142, 143;
isothermal changes in, iv, 156;
latent heat of, 153, 173-4, v, 353, 354 (see Latent Heat);
laws not inflexible, iv, 142-3;
liquefaction of, 143, 153, 191-2 (see Liquefaction);

Mariotte's law, 141;
mechanical energy of, 142;
molecular velocity in, 133;
molecules in, iii, 309, iv, 22, 131, 132-3, 152-3, viii, 23, 24, 106, 305-6;
molecules, number in, iv, 133, viii, 108-9, xvi, 133;
monatomic, viii, 309;
pressure of, v, 223, viii, 24-5, 109-10;
pressure, to what due, iv, 30, 132-3;
pressure, volume, and temperature laws, iv, 125-6, 139-43, v, 347, viii, 106-8;

Regnault's constant, iv, 142;
solidifying of, i, 32, iv, 153, 192;
solubility in water, viii, 40, 111, 112;
sound velocity in, iv, 155-6, 198, 199;
specific heat ratio, 155-6, 159;
spectra of, ii, 112-13, iv, 361-3;
suspended change of state, viii, 113, 304, 305;
vibration of, iv, 215;
volume taken at atmospheric pressure, v, 223
Gas Lighting, vi, 195, 264;
fire hazards, vii, 51
(see also Illuminating Gas)
Gas Mantles, viii, 60, 252
Gasoline, combustion of, viii, 13, 52;
explosiveness, vii, 124, viii, 23, 54, 62;
production and uses, 208, 209, 235
Gasoline Engines, v, 156-61;
in aeroplanes, 231;
efficiency, 155;
compared with motors, vii, 223;
operation, 123-33
Gas Plant, xiii, 136-7
Gas Shells, i, 308, 314, viii, 263
Gastric Digestion, ix, 234-6, x, 319-25
Gastric Glands, control of, ix, 162, 240-2

Gastric Juice, viii, 358, ix, 234-8, x, 319-20;
control of secretion of, ix, 240-2;
conveyance of, 189-90;
disorders of, x, 321-3;
historical studies of, ix, 239-40;
indigestion from failure of, 239-41
Gas Warfare, viii, 262-4, x, 186-8
Gatling Guns, v, 362-3, 364, 380
Gatun Lake, Panama, xiv, 195
Gaurs, xii, 330
Gay-Lussac, balloon ascensions, i, 18;
chemical work, xvi, 133, 160, 162
Gazelles, xii, 327

Gearing, in turbine-driven ships, v, 105, 153-4, vii, 329

Gears, v, 25-31;
hydraulic, 104-6;
spiral, 38-9;
toothed, disadvantages, 104;
worm, 37 (fig.), 38
Geckos, xii, 205-6
Geese, xii, 257, 258

Gelatine, colloidal state, viii, 314, 315, 356;
food value, ix, 288

General Electric Company, autotransformers, vi, 337;
bulletin on motor costs, vii, 224-6;
machinery for Niagara Plant, vi, 374, 375, 376, 377;

Mazda lamps, 267;
radio engineering work, vii, 274;
small power sets, 232
Generators, vi, 49-56, vii, 369;
alternating current, vi, 158-9, 196-216
(see also Alternators);
armature reaction, vii, 145-6;
direct current, vii, 175-94
(see also Direct Current Generators);
efficiency, vi, 192-4, 214-15, 357, 379;
electrostatic, 298-301;
induction motors as, 249-50;
neutral points, vii, 373;
operation in power plants, vi, 357-8, 362;
of Niagara Plant, 374-5;
principal parts, 176;
purpose and parts, vii, 367;
radio, 274-8, 282-3, 290-1;
ratings, vi, 192-4, 214-15;
regulation of output, vii, 144-50;
short-circuit protection, 49;
size of units, vi, 378-9;
slow and high speed, 182;
turbine-driven, v, 151, 154;
use in therapeutics, vii, 236-7, 241-5
(see also Dynamos)
Genetics, xvi, 157-8

Geneva Lake, filling of, by Rhone River, xiv, 53;
former connections, 185;
slow movement of water, 210

Genital Organs, foci of infection in, x, 220, 221

Genius, Bessel on, ii, 93;
obstacles and, xvi, 30;
reflex action of, xi, 36;
Titchener on, 225-6
Genoa, growth of, xiv, 308;
sea captains of, 310
Gentians, xiii, 190, 205

Genus, Genera, defined, xii, 28, xiii, 170, 171

Geocentric Theory, ii, 9-10, 34-5 (see Ptolemaic System)

Geo-Chemistry, viii, 190-203

Geocoronium, i, 192, 373

Geographical Change, agents of, xiv, 31-2, 33-79

Geographical Cycles, xiv, 29, 34-5, 48 (see Cycles of Erosion)

Geographical Distribution, science of, xvi, 140

Geography, changes since prehistoric times, xiv, 29-30;
civilization and, xv, 122-3, 128-39;
defined, iii, 9-10, 379, xvi, 36;
development of science of, 94, 98, 114, 123-4;
genetic conception of, xiv, 3-4;
history and, 10, 30-1, 191-7, 239-45, 249-50, 261-2, 279-82, 305-11

Geological Ages, iii, 19-21, xv, 71;
determined by fossils, iii, 15, 18-19;
estimate of lengths, xiii, 314, 322;
length seen in coal formations, iii, 201;
length seen in chalk deposits, 218;
length shown by mosses, xiii, 306
Geology, Volume iii
Geology, daily interest, xvi, 22-5;
definition and scope, iii, 3, 9, 11, 12, 378, xvi, 37;
history of development, 126, 168-73;
mineralogy and, iii, 309
Geometry, of Greeks and Hindus, xi, 239-40;
history of, xvi, 54, 68, 81, 89, 90
George, Lake, iii, 145;
stream changes around, 243
Georgia, aluminum production, iii, 369;
cotton of, xiii, 237;
glacial period in, xiv, 376;
soil of, 218
Georgian Planet, ii, 267
Geotropism, xiii, 85
Geranium Family, xiii, 200
Geraniums, fertilization, xiii, 136;
killed by hot water, 299;
multiples of five in, 176;
turning to light, 85;
petal arrangement, 190
Germanium, discovery, viii, 180;
symbol and atomic weight, 383
Germans, in Alpine group, xvi, 49;
grouped as Huns, xi, 22
German Silver, copper alloy, viii, 164;
resistance, vi, 76, 77

Germany, aeronautical weather service, i, 304;
barley growing in, xiv, 365;
beet sugar production, xiii, 216;
coal deposits, iii, 345;
coasts of, xiv, 247;
early surgery, xvi, 181;
earthquakes of, xiv, 128;
forest policy, xiii, 372, xiv, 238-9, 382;
geological works, xvi, 170;
hail insurance, i, 344;
in World War (see World War);
loess deposits, xiv, 72;
medicine of, Muller's influence, x, 118;
meteorological establishments, i, 222-3;
meteorology in World War, 309, 310;
military aviation development, 40;
mining products, iii, 362, 364;
moor fires in old, i, 56;
mountains of, xiv, 96, 235;
nitrogen fixation in, i, 36-7, xiv, 66;
plains of, 217;
potash deposits, viii, 130, 143, 144, 344, xiv, 67-8, 209;
salt beds of north, iii, 204, xiv, 141;
"sheep-cold", i, 363;
topography of western, xiv, 87 (map), 90;
unke toad of, xii, 176

Germ Cells, ix, 324-5, 327, 332, 339, x, 232, xvi, 156, 157-8;
in reproduction, x, 233;
source of, xii, 27
(see also Germinal Tissue, Germ Plasm)
Germinal Tissue, ix, 324-5;
chromosomes of, 328, 329, 339;
development of germ cells in, 332, 339;
heredity dependent on, 325-8;
independence of, 325
(see also Germ Plasm)

Germination of Seed, after low temperatures, i, 32;
acacia plant
of Natal, xiii, 375;
ancient wheat grains, 211, ix, 16-17;
bird-carried seed, xiii, 340, 341;
seed in sea water, 346, 348
Germ Plasm, x, 228, 229;
immortality theory, 230;
origin of energies, xvi, 145;
theory of inheritance, x, 233-4, 235, xvi, 156

(see also Germinal Tissue)

Germs, disease-producing, (see Disease Germs);
in body, ix, 177;
universal presence of, x, 193-4
Gestures, language of, xv, 146-52, 167-8
Geyserite, iii, 335
Geysers, iii, 128-9, xiii, 299;
artificial, in Michigan, v, 92
Gharials, xii, 199, 201
Ghizeh, Pyramid of, xiv, 78, xv, 270;
temples of, ii, 26
Ghor, of Syria, xiv, 120-1
Ghosts, as visual hallucinations, xi, 91

Giant and Dwarf Stars, ii, 153, 294, 309, 310, 382-4

Giant's Causeway, Ireland, xiv, 104;
columnar structure, iii, 111, xiv, 129
Gibbons, xii, 381-2;
reasoning power in, xv, 67;
skeleton compared with man, 59
Gibbs, James E. A., v, 285
Gibbs, J. W., xvi, 136, xvi, 169
Gibraltar, apes of, xii, 378
Gibraltar, Strait of, depth, xiv, 299
Giddiness, sensation of, xi, 126
Giffard, Henri, v, 227
Giffard Injector, v, 140-2, 380
Gila Monster, xii, 204, 207

Gilbert, Dr. William, electrical work, vi, 11-12, xvi, 109, 111, 188

Gilbertus Anglicus, x, 41
Gills, of fishes, xii, 128, 135;
functions and structure of, ix, 253, 254
Gills (plant), of mushrooms, xiii, 163
Ginkgo Tree, xiii, 315-16, 326
Ginseng, antiquity, xiii, 324-5;
distribution, 351;
origin, 255
Giraffes, xii, 320-1;
trapping of, xv, 224 (fig.)
Giralda Observatory, xvi, 100, ii, 38
Girls, education of, xi, 266-7

Givler, Prof. R. C., author "Psychology," Vol. xi

Glacial Bowlders, iii, 70, 237, 352 (Pl. 20), xiv, 69, 70

Glacial Deposits, iii, 66-70, xiv, 59, 60;
in U. S. and Canada, 170-1;
lakes formed by, iii, 144-6, xiv, 200-2
Glacial Epoch, iii, 236-48;
distribution of plants and animals, xiv, 375-7;
drainage changes, 30, 52, 164, 170-1;
fjords due to 259-61;
lakes formed by, iii, 143-51, xiv, 200-2;
topographical changes, 3, 30, 59-62, 158, 170
(see also Ice Age)

Glacial Periods, theories of, i, 58, iii, 247-8

Glacial Plants (see Arctic Plants)
Glacial Soil, xiv, 63, 69-70
Glacial Valleys, xiv, 56-8

Glacier National Park, cliff glaciers in, iii, 60;

Swift Current Valley, Plate 5, p. 96;
thrust faulting in, 90
Glaciers, iii, 59-62, xiv, 54-5;
"autographs of," 56;
cirques of, 58;
cracks and fissures in, iii, 63;
defined, 379;
deposits of, 66-70, xiv, 59-60;
erosion by, iii, 63-70, xiv, 55, 56, 57-8, 60-2, 233;
falls formed by, iii, 48;
flow, 62-3, 68, 240-1, iv, 165-6;
lakes formed by, iii, 142-51;
occurrence, xv, 72-3;
topography produced by, xiv, 42-3, 44, 55-62;
valleys cut by, iii, 64, 65, 66
(see also Plates 4, 5, and 6);
valleys "overdeepened by," xiv, 259-60
Gland Cells, functions, ix, 39, 43, 59;
number unchanging, 48
Glanders, germ of, x, 195;
immunity to, 207
Glands, activity and blood supply, ix, 220-1;
adrenalin effects on, 171;
control of, 159-69, x, 346-7;
ductless, x, 346-53;
energy release by, xi, 24;
fatigue effects, xi, 272;
nerve connections, ix, 159-60;
reflex responses by, xi, 23;
with ducts, x, 347
Glare, direct and reflected, vi, 277-8
Glasgow, soot-fall, i, 65

Glass, antiquity of, viii, 269, 280-1, xvi, 73-4;
coloring of, viii, 282;
colors in X-rays, iv, 378;
composition and properties, viii, 281, 304-5;
effects on light and heat waves, iv, 183;
electrification of, 257, 258, 259;
ground by sand blast, 130;
heat conductivity, 179;
light decomposition by, ii, 100-1;
light deviations in strained, iv, 330;
light refraction by, 327;
sodium compounds in, viii, 137, 146

Glasses (lenses), for various eye defects, ix, 111, 112, 113, 114

Glazed Frost, i, 108, 121, 373
Glidden, Carlos, v, 312
Glisson, Francis, x, 86, xvi, 178
Globefishes, xii, 164
Globigerina Ooze, xii, 18
Globular Clusters (Stars), ii, 336-40;
Hyades as, 342;
studies of, at Mt. Wilson, 159-60

Globular Lightning, i, 149, vii, 205-6, 213-15

Glory (meteorology), i, 184-5, 373
Glowworms, i, 346;
Fabre's studies, xvi, 144

Glucinum, atomic weight and symbol, viii, 180, 383;
in calcium group, 148
Glucose, viii, 225-6, 377, ix, 230;
converted from cellulose, viii, 255;
fermentation of, 225, 248;
formula, 219, 225, 229;
in human body, 359;
manufacture and uses, 228, 243-4;
production by plants, 335;
use of, by body, ix, 230, 243, 244, 245
Glutton (weasel), xii, 348, 349
Glycerine, viii, 215, 247-8;
base of fats, 221, 245;
boiling point, 299;
melting requirements, iv, 162;
production in wine-making, x, 138
Glycogen, xi, 136-7, 138;
chemistry of, viii, 228-9, 350;
production and storage in liver, 359, ix, 291, 292, 297, 298, x, 329;
reconversion into sugar, ix, 293
Glyptodon, xii, 283-4
Gnawers, xii, 285-96
Gneiss, iii, 379;
formation, 169, xiv, 19;
jointing of, 133
Gnomons, ii, 24, 25, 300
Gnus, xii, 327
Goats, xii, 325-6;
horns of, 328;
usefulness, 324
Gobar, of Nile region, i, 96
God, conceptions of, xv, 344;
ideas of, in Old Testament, 374
Goddard Rocket, i, 22-3
Godman, John, x, 116, xvi, 185

Gods, evolution of belief in, xv, 341-4, 347-8, 357

Goethe, evolution known to, x, 136;
on cloud forms, i, 98
Goethals, Panama Canal Zone work, x, 162
Goitre, ix, 303;
exophthalmic, x, 272, 276-7, 351-2;
removal of thyroid gland in, 349
Gold, atomic weight and symbol, viii, 383;
California mines, iii, 226, 365;
chemical inactivity, viii, 127-8, 163, 174;
contraction on solidifying, iv, 150;
density of, 113;
electrolytic refinement, vii, 301, 320;
extraction methods, viii, 131, 141, 170, 174, 269, 270;
fusibility, 384;
in sea water, 197, xiv, 295;
melting point, iv, 162;
metallurgy, development of, xvi, 176;
occurrence, iii, 330-1, 365-7, viii, 131, 198;

"parting" of silver from, 272;
positiveness, vi, 59;
production, iii, 365;
profitable ores, viii, 197;
properties, 126-7, 174, iii, 330-1;
recovered in copper refining, vii, 319, 320;
specific gravity, viii, 384
Golden Age, x, 18, 20;
of Greek science, xvi, 86-96
Golden Gate, formation, xiv, 258;
furrow of, 287
Goldenrod, bracts, xiii, 43;
stems, 23;
in the pampas, 376
Golden Showers, i, 61
Goldfish, family of, xii, 161;
in liquid air, i, 32
Gold Leaf, color between glasses, iv, 324
Gold Mining, dredges in, v, 256-7;
water jets in, 88
Gold-Plating, of aluminum, vii, 319
Goldschmidt Generators, vii, 274
Goldschmidt Method, of welding, viii, 155
Golf, as exercise, x, 317;
report of match, xi, 161
Goodwin, Rev. Hannibal, v, 330
Goodyear, Charles, xiii, 245
Goose Barnacle, xii, 84-5
Gooseberry, origin, xiii, 225
Goose-Flesh, ix, 161, xi, 112-13, 123
Gophers, xii, 290, 294;
badgers and, 348
Gopher Snake, xii, 219
Gopher Turtle, xii, 191
Gorals, xii, 325
Gordius (hairworm), xii, 45

Gorgas, William C., yellow fever work, x, 162, 172

Gorges, formation of, xiv, 50-1, 51-2;
in old and new areas, iii, 33, 34;
of New York and New England, 44, 242-3
Gorham, Marquis L., v, 248, 381
Gorillas, xii, 382 (fig.), 383-4;
brain weight of, xv, 62;
physical comparison with man, 57-8;
family groups among, 276, 360-1;
use of stones and clubs, v, 9
Gorner Grat, boiling temperature at, iv, 170
Gouffre, i, 196, 373
Gourd Seed, growth of, x, 229
Gout, uric acid and, x, 343

Government, beginnings of, xv, 360-74, 379-80;
cultivation and, 380

Grackle, coloring of, xii, 245

Gradients, meteorological, i, 373 (see Barometric, Potential Gradients)

Graduated Flask, viii, 294, 295
Graham Flour, ix, 34
Graham's Law, viii, 108-9
Grain Cradles, v, 240-1
"Grain of the country", xiv, 99;
in river classification, 153
Grains, fruit of grasses, xiii, 56, 182;
milling of, xv, 237-9;
proteins in, ix, 34;
"showers", i, 357;
storing of, viii, 371
Gram, unit of force, iv, 70;
unit of mass, iv, 46, 69, viii, 28;
value in pounds and poundals, iv, 70
Gram-Molecular Volume, viii, 109
Gramophone, v, 328-9, 382
Grampuses, xii, 297
Grand Banks, dogfish of, xii, 146;
petrels of, 252;
scallop fisheries of, 65

Grand Canyon of the Colorado, iii, 40-3, 140, 230, xiv, 83;
conical fragments in, 81;
outer and inner gorges, 173;
plateau of, 124, 159, 220;
Proterozoic strata in, iii, 177;
rock pyramids in, xiv, 224-5

Grand Canyon of the Yellowstone, iii, 44, and Pl. 2, p. 48;
color of rocks in, 26;
youthful valley type, 33;
relief model of, xiv, 10
Grand Point Tobacco, xiii, 258

Granite, composition, iii, 308, 326, viii, 192-3;
disintegration of, 194;
igneous nature, iii, 112;
jointing of, xiv, 133;
mountain cores of, 110-11;
occurrence and production, iii, 371;
plutonic rock, 13, xiv, 18;
weathering of, iii, 22, 27-8, 32 (Pl. 1), xiv, 78-9;
wells in, 137
Grapes, acids of, viii, 223;
origin and antiquity, xiii, 225, 324-5;
true berries, 54;
water content, viii, 365
Grape Sugar, viii, 224-5;
polarization of light by, iv, 356
Grapevines, xiii, 27, 28
Graphite, iii, 331, viii, 43;
in Archeozoic rocks, iii, 173, 249-50;
Rhode Island beds, 345;
use and production, vii, 308-9, xvi, 190
Graptolites, iii, 259, 266 (fig.), 267
Grasp, in infants, ix, 349, xv, 61;
of man, ix, 67-8;
grasping importance and organs of, 82;
reflex processes in, 157, 349
Grasping Reflex, xi, 40-5, 59
Grass, blue-eyed, xiii, 189;
leaves of, 176;
monocotyledon, 178;
veins, 32
(see also Grass Family)

Grasses, dominant on prairies, xiii, 350, 374;
evolution, iii, 251, 257;
fertilization, xiii, 148;
first appearance, 319;
true and incorrect, 179, 180;
water requirements, xiv, 381
Grass Family, xiii, 179, 181-3
Grasshoppers, xii, 108-10;
jaws of, 100
Grasslands, xiii, 373-7;
contests with forests, 348-9, 368 (illus.), 374-5, xiv, 380-1;
distribution of, 380, 381;
economic importance, 383-4;
vegetation of, 380, 381
Gratitude, sentiment of, xi, 147
Graupel, i, 107, 373

Gravel, rocks formed from, iii, 13, 53 (see Conglomerate);
sedimentary rock, xiv, 18
Grave Sacrifice, custom of, xv, 336
Graves, Robert, x, 112
Graves Disease, x, 351-2

Gravitation, universal, discovery and laws, ii, 63-72, iv, 20, 95-8, xvi, 115-16;

Einstein theory, ii, 79-82;
magnetic force compared with, iv, 249-50;
nature of, ii, 78;
things unexplained by Newton's laws, 73-4, 78-82;
various applications of Newton's laws, 77, 78, 375, 380

(see also Gravity)
Gravitation Units, iv, 64, 70
Gravity, ii, 63-4, 69, iv, 65, 109;
acceleration of, 65;
center of, 99-101;
direction of earth's, 98-9;
force in falling bodies, 42, 65, xvi, 32;
gyroscope and, v, 335, 336, 337-9;
Huygens's studies, ii, 58;
on asteroids, 257;
on moon, 199, 204;
on sun, 168;
Richer's observations, 59;
water-power due to, v, 76-7, 139;
weight due to, iv, 58, 74, 109
Gravity Battery, iv, 297, vi, 137, 140-1
Gravity Faults, xiv, 115
Grayfish, i, 224
Graylings (fish), xii, 159
Gray Matter, ix, 124;
of brain, xv, 63
Great Auk, xii, 265
Great Basin, block mountains in, iii, 138-9;
drainage changes in, xiv, 188;
faulting in, iii, 89, 229, xiv, 117, 127;
formerly submerged, iii, 181;
not being worn down, 32;
saline lakes of, xiv, 206;
streams, base level of, 164;
wind-eroded materials of, iii, 73

Great Britain, aerial travel statistics, i, 50;
aeronautical research, 51;
animals of, xiv, 272-3;
coal supply, iii, 345;
coast destruction, xiv, 46;
empire of, 279;
geology related to continent, 271-2;
manufacturers, American System in, v, 50;
manufacturing future, 173;
rainfall of, xiv, 41;
recent separation from continent, 30, 271-3;
serpents of, xii, 218;
soot studies, i, 65;
standard units in, iv, 45-6;
storm signals, i, 282;
thermometer scale in, iv, 136;
tides of, xiv, 293-4
"Great Eastern," steamship, v, 193

Greater Antilles, geological history of, xiv, 274-5

Great Indian Earthquake, xiv, 333, 334, 335, 336 (fig.);
cause, 340
Great Lakes, commerce on, xiv, 62, 212;
fish of, xii, 156, 159;
former drainage farther north, iii, 46;
level changes in region, 82;
origin and history, 146-51, xiv, 61, 62, 201-2, 203;
recentness of formation, iii, 12;
recessional moraines near, 67;
sewage disposal in, viii, 325;
sizes and depths, xiv, 204;
water supply of Lake cities, 140
Great Plains, elevation of, xiv, 27, 213;
evaporation in, 135;
geology of, 215;
grasses of, xiii, 181, 374, xiv, 380, 381;
horses of, xii, 306, 307;
pronghorns on, 322-3;
red beds, iii, 208;
rejuvenation, 230;
rodents of, xii, 294;
stock-raising on, xiv, 383-4;
trees in, xiii, 372-3, 374, xiv, 372;
volcanic action in, 318;
wind-fertilization of plants, xiii, 149
Great Rift Valley, xiv, 117-21;
lakes in, 203;
volcanoes of, 317
Great Salt Lake, crustal warping at, iii, 82;
history and formation, 152-3, xiv, 207-8;
mirages, i, 172;
plain of, xiv, 215-16;
salt in, iii, 374, viii, 139, 140, 275
Great Sea Waves, xiv, 337-343
Grebes, xii, 250-1
Greece, earthquakes of, xiv, 332, 333-4;
geographical changes in, 33;
rainfall of, 358;
rift valleys in, 123
Greece (ancient), astrology in, ii, 21;
Babylonian influences, xvi, 63;
civilization conditions, xv, 123;
civilization pictured in Odyssey, 324;
copyists of, 178-9;
foreigners called barbarians, xi, 22;
Golden Age, x, 20, xvi, 86-96;
musical instruments, xv, 316, 317 (fig.);
northern invasion, xiv, 281;
religion and science associated, xvi, 44;
slavery in, xv, 378-9;
timing of orators, v, 62;
weather records, i, 67-8

Greek Astronomy, ii, 10-11, 27-36, xvi, 81-2, 90-1

Greek Language, xv, 162

Greek Medicine, x, 16-25, xvi, 95-6;
preservation and revival of, x, 31, 36, 43-4, 45

Greek Philosophers, remarks on, ii, 27, 30;
on origin of earth, 366-7

Greeks (Ancient), boiling of foods unknown to, xv, 233;
degeneration of stock, xvi, 96;
gods of, xv, 343, 352;
idea of insanity, x, 356, 357;
idea of soul, xv, 330;
in Mediterranean group, xvi, 49;
intellectual height, 50;
knowledge of loadstone, vi, 28, 29;
monsoons used in navigation, i, 130;
oar-propelled ships, xiv, 265;
plants known to, xiii, 215, 216, 253;
sacrifices of, xv, 347-8;
scientific bent, xvi, 54;
superstitions of, xv, 355;
surveying inventions, xvi, 68-9;
trade and colonies of, xiv, 307
Greeks (modern), in Alpine group, xvi, 49
Greek Science, xvi, 75, 76-96;
debt to Egypt, 75;
influence on Copernicus, 102;
Roman development of, 99;
spread and continuation of, x, 23, 25
Greek Sculpture, xv, 302
Greek Vases, xv, 251, 253 (fig.)
Green, complementary color of, iv, 367;
effect on blood pressure, xi, 63;
in interior decoration, vi, 274;
primary color, iv, 366;
seeing of, in color-blindness, ix, 116
Green Flash, i, 170-1, 373

Greenhouses, effects of glass on heat, i, 59, iv, 183;
electric lighting, xiii, 76
Greenland, climate, xiv, 345;
discovery, 261;
fjord coasts, 258, 259;
foxes of, xii, 344;
glaciers of, xiv, 55;
ice sheets, iii, 61-2, 237;
marriage customs in, xv, 282-3;
mirages, i, 173;
ocean colors near, xvi, 147;
rainlessness, i, 109;
winds, 128, 129
Greenland Ranch, Cal., i, 209
Green Mountains, iii, 188
Green River, Uinta Mts., xiv, 166, 168, 175

Greenwich Observatory, founding of, ii, 83, xvi, 124;
publications, 125
Grenville Strata, iii, 165-8
Grew, biologist, xvi, 112, 116, 126
Greylock, Mount, iii, 232
Grief, exhaustion from, xi, 135-6;
expression of, by monkeys, xv, 65
Ground Sharks, xii, 143
Grinders, invention, v, 48, 381
Grip, disease, x, 294-5
Grison, xii, 349
Ground Moraines, iii, 67
Ground Pines, iii, 254
Groundsel, seed disposal, xiii, 345
Ground Water, iii, 113-29, xiv, 135-52;
how plants absorb, xiii, 91-3;
landslips facilitated by, xiv, 233;
mineral concentration by, iii, 126, xvi, 173;
petrifaction by, iii, 15, 126-7;
rivers and, xiv, 157
(see also Soil Water)
Ground Wires and Plates, vii, 369
Groups, Chemical, viii, 93, 377;
interchange principle, 211;
ionization, 121-2;
nomenclature, 97;
valences of, 94
(see also Radicals)
Groups (human), formation of, x, 9, xv, 361-3
Grouse, xii, 261
Growing Season, i, 373
Growth, age in relation to, ix, 47-8, 288-9;
by cell division, 43-8;
chemical regulation of, 169-70;
food requirements for, 31-4, 286-8, 295;
life and, xii, 13;
metabolism of, ix, 38-9, 295;
of bones, 56, 58;
of skin, 312;
of various tissues, 47-8, 286-7;
of skull, xv, 40;
rate of, in man, ix, 32 (diagram);
vitamines necessary to, x, 261, 262

Gruener, Prof. H., author Chemistry, Vol. viii

Guam, ocean depths near, iii, 51
Guango Tree, i, 350
Guatemala, Santa Maria eruption, xiv, 328-9
Guava, xiii, 196, 225
Guayaquil, sanitary measures, i, 327;
yellow fever campaign, x, 173
Guericke, Otto von, iv, 29, 116, xvi, 110
Guillemots, xii, 264-5
Guinea Pigs, xii, 289;
anaphylaxis in, x, 213
Gulf Coastal Plain, xiv, 214;
chalk deposits, iii, 266;
Cretaceous deposits, 216;
geological history, 222, 231

Gulf Stream, climatic influences of, viii, 37, xiv, 304;
meeting with Labrador current, 305;
origin and course, 304;
"paper sailors" of, xii, 78;
plan for protecting, i, 345;
Portuguese man-of-war in, xii, 37;
seed dispersal by, xiii, 346
Gull, Sir William, xvi, 180, 184
Gulls, xii, 264
Gum Arabic, source, xiii, 226
Gumboils, ix, 56, 187
Gums, composition of, viii, 223, 229;
electrical conductivity, iv, 259
Gums (mouth), chilling of, by ether, iv, 174;
germ infection through, x, 202, 219, 222

Guncotton, composition and action, viii, 63, 255, 261;
discovery, xvi, 163
Gunite, v, 136
Gunnison River, Colorado, xiv, 172-3, 175
Gunny Sacks, xiii, 241
Gunpowder, viii, 144-5;
explosion, v, 156-7, viii, 62, 145;
introduction, v, 361, 368, xvi, 101
Guns (big), v, 368-71;
locating of, by sound velocity, i, 313, iv, 201-2;
making of, v, 323-5;
operation on battleships, v, 104, vii, 333-4;
phenomena in World War, i, 193-4
(see also Artillery, Projectiles)

Guns (small), development of, v, 361-2, xv, 213, 216-19;
kick, v, 143;
kick utilized in Maxim gun, 363;
machine, 362-8;
percussion lock invention, 377;
standardization in manufacture, 49-50
Gunshot Remedies, vii, 241, x, 76
Gunter, Edmund, xvi, 104
Gushers, oil, iii, 353-4
Gusts, i, 295, 373
Gutenberg, Johann, v, 300;
printing invention, xv, 179
Guttation, of plants, i, 350-1
Guyon, Felix, xvi, 184
Gymnarchus Fish, xii, 154
Gymnastic Exercises, x, 304-5
Gymnosperms, xiii, 174, 175, 178;
alteration of generations, xvi, 166;
first appearance, iii, 252, 255
(see also Conifers)

Gynecology, development of, x, 80-1, 122, xvi, 180

Gypsum, iii, 331-2, 375-6;
composition, viii, 153;
deposits and use, xiv, 209;
in sea water, 295
Gyro-compass, iv, 254-5, v, 201, 340, 384
Gyroscope, iv, 254-5, v, 335-44, 384;
in torpedoes, 373

Gyroscopic Action, of bullets and shells, v, 362

Haber Process, i, 36-7, viii, 74, 105, xvi, 165

Habit, xi, 247-58;
autosuggestion and, 306;
in physical functions, ix, 81, 88, 251;
slaves of, xi, 263;
will and, 261
Habits of Thought, xi, 198, 203-4, 247
Habitual Images, xi, 222
Hackberry Tree, xiii, 194

Haeckel, Ernst, biological work, x, 136, xvi, 182;
on phosphorescence of sea, xii, 18-19
Hail, i, 106-8, 373-4;
formation, 120;
storms and stones, 119-20
Hail clouds, i, 102
Hail Insurance, i, 269, 344
Hail Rods, i, 341, 342-3, 374
Hail Shooting, i, 341-2, 374
Hailstorms, devices to avert, i, 340-4
Hair, cells of, ix, 13;
color and form in different races, xv, 37-8, xvi, 48, 49, 50;
cutting of by electricity, iv, 10;
dyeing of, x, 58;
emotion effects on, xi, 142;
erection of, ix, 161, 162, 166, xi, 113;
of mammals, xii, 270-1;
on face and body, xv, 38

Hairdressing, among savages and Chinese, xv, 260-1;
ancient Egyptian, 255 (fig.)
Hairsprings, v, 70, 71-2
Hairworms, xii, 45
Hags (fish), xii, 130, 131
Haiti, gouffre of, i, 196;
rubber growing, xiii, 245;
words derived from, xv, 161;
yellow fever of, x, 160;
zoölogy of, xiv, 274
Hakemite Tables, ii, 38, 39

Hale, Prof. George E., ii, 147, 148, 177, 178, 225, 241;
spectroheliograph of, 129, 183
Hales, Stephen, x, 88, xvi, 112
Halite, iii, 332
Haller, Albrecht von, x, 77, 87-8, 97, 98;
medical works, xvi, 178

Halley, Edmund, comet and other discoveries, ii, 83-9;
discovery of moon's deviations, 73;
discovery of star motions, 304;
on Eta Argus, 324

Halley's Comet, ii, 84, 85-6, 273-4, 275, 281;
tail of, 134
Hallucinations, definition and kinds, x, 358;
of crowds, xi, 328-9;
visual, 91
Hallucinatory Images, xi, 221
Halogenation, viii, 266, 377
Halogen Derivatives, viii, 210, 211-12, 236
Halogens, viii, 18, 84-7, 377;
similarity of, 176
Halos, i, 177-183, 374;
circumscribed, 181, 369;
tangent arc, 383
Haly, "Royal Canon," of, x, 32, 37
Hamadryad, xii, 228-9
Hamburg, Deutsche Seewarte, i, 223, 276;
harbor of, xiv, 270
Hamilton Mill, vi, 296, vii, 209
Hamilton, Mount, ii, 142
Hammers, measurement of blows of, iv, 67;
pneumatic, i, 28
Hammurabic Code, xvi, 63;
on medical practices, x, 15

Hands, ape's and human compared, xv, 57, 58-60;
bones of, ix, 67-8;
cold or warmth felt in, 320;
color in different lights, iv, 364-5;
deftness of human, v, 248;
evolution of, xii, 167-8;
grasping reflex of, ix, 349, xi, 40-5;
importance in child's education, 43;
origin of flexed position, 42-3;
reciprocal innervation, 86;
tools resembling, 44-5;
temperature of, ix, 93;
X-ray pictures of, iv, 55
Hangars, i, 43
Hanging Glaciers, iii, 60-1
Hanging Valleys, iii, 65, xiv, 57
Hanks, of yarn, v, 272
Hanseatic League, xiv, 28, 308
Harbors, xiv, 266-71;
necessity of, to modern ships, 265;
photographic mapping of, i, 47-8
Hard Coal, combustion process, viii, 45;
flames from, 57;
origin, xiii, 10 (see Anthracite Coal)
Hardening of Arteries, x, 334-6, 340
Hardening Processes, (health), x, 240
Hardness, defined, viii, 377;
scale of, iii, 320, viii, 202;
sensation of, xi, 128
"Hard Shell," xii, 83

Hard Water, cause, iii, 126, viii, 151, 322-3, 377;
effects of, 143, 151-2, 323;
effects, xiv, 147;
occurrence in nature, ii, 147;
softening of, viii, 323-4;
taste of, 40
Hares, xii, 286-8

Hargreaves, spinning jenny, v, 273, 376, xv, 246

Harmattan, i, 134, 374
Harmonica, iv, 235
Harmonics, iv, 213
Harmony, due to tonal fusion, xi, 106
Harney's Peak, xiv, 227
Harpoons, xv, 209 (fig.), 210-12
Harps, development of, xv, 318
Harpsichord, xv, 318
Harrisburg, Pa., topography near, iii, 36
Harrison, John and William, v, 66-7
Hartness, telescope of, ii, 101
Harun-al-Raschid, astronomy under, ii, 37

Harvard Classification of Stars, ii, 116-18, 146, 310

Harvard College, first eclipse expedition by, ii, 211

Harvard Football Team (1913), excitement effects, xi, 138

Harvard Observatory, Arequipa station, ii, 145-6, 148;
photographic work, 116, 118, 127, 130, 136, 137, 301-2;
star spectra studies, 307
Harvard Photometry, ii, 297
Harvesting Machines, ancient, v, 240;
modern, 244-9
Harvestmen (scorpions), xii, 90
Harvest Moon, ii, 196
Harvey, William, x, 61-2, 66-7, 97;
discovery of circulation of blood, ix, 192, x, 22, 61, 63-6, 69, 81, xvi, 106-7, 142;
other work, 107, 111
Hashish, xiii, 239
Hate, emotion of, xi, 139;
motor character, 58;
sentiment of, 148-9
Hats, hygiene of, x, 240, 309;
renovation by electricity, iv, 10
Havana, harbor of, xiv, 268;
sanitary measures, i, 327, x, 162;
water supply, xiv, 140

Havemeyer, Dr. L., author Anthropology, Vol. xv

Havre, port of, xiv, 271
Hawaii, geological formation, xiv, 101;
paper in sugar-growing, v, 291;
radio station, vii, 281;
screw pine of, xiii, 354

Hawaiian Islands, lava formations, iii, 28, 103;
oceanic character, xiv, 276;
rainfall on Mt. Waialeale, i, 112;
trade wind effects, xiv, 356;
volcanic soils, 329;
volcanoes, iii, 103-5, xiv, 322-3
Hawaiian Music, xv, 315
Hawk Moths, xii, 119-20;
facets of, 102
Hawks, xii, 260, 261;
man's lesson from, xv, 206
Hawksbee, Francis, xvi, 122-3
Hay Fever, cause of, x, 212, xiii, 118
Haze, atmospheric, i, 374;
dry fog, 96;
dust (African coast), 55;
from smoke, 56, 57;
in distance perception, xi, 182
Hazel Copses, xiii, 370
Hazelnut Tree, xiii, 193
Head, binding of, among savages, xv, 260;
blood supply of, ix, 197;
bones of, 61-3;
motions and position, how sensed, 90;
saving heels by, xi, 376-7;
shape in race classification, xv, 42-3;
washing of, x, 312;
word, various uses of, xv, 158-9

Headaches, electrical treatment, vi, 285, vii, 238-9;
eyestrain and, ix, 113;
hypnosis and, xi, 315;
significance of, 120-1
Head of Water, v, 94;
high and low, 79-81
Health, care of, instruction in, x, 282-5
(see also Personal Hygiene);
dependent on kinetic system, xi, 61;
emotions and, 129;
mental efficiency and, 369;
regulation to environment, x, 249-50;
resistance to disease strengthened by, ix, 185-6;

Science of, vol. x;
worry and, ix, 167
Health Resorts, i, 331

Hearing, iv, 203-4, 211-12, ix, 98-103, xi, 98-108;

"arrival platform" for, ix, 146;
colored, xi, 222;
direction perception by, ix, 117, 120;
distance perception by, 121;
ear movements and, 82;
in fishes, xii, 137-8;
in insects, 101;
limits (vibration rates) of, iv, 204, ix, 99, 100;
nerve of, 30;
organ of, position, ix, 61;
sense of, in infants, 351;
space perception by, xi, 163, 167-9
Heart, anatomy and operation of, ix, 200-12;
of, x, 332, 333-4;
as seat of affections, ix, 200;
emotion effects on, ix, 200, xi, 135, 136-7;
emotions attributed to, 130-1;
examination methods, ix, 205;
exercise effects, 261-2, x, 303, 304-5;
fatigue effects, xi, 272;
fear and terror effects, 131, 132;
high temperature effects, x, 251;
hypertrophy of, 331-2;
motions, Harvey on, 64-6;
nerve centers and control, ix, 168;
part in maintenance of life, 21-3;
passage of blood through former ideas, x, 52, 62, 65-6;
removed from body, beating of, ix, 84;
rest and sleep needs (eight-hour day), 209-10;
septum of, x, 66, 113;
sleep effects, xi, 283;
sounds, how listened to, ix, 205-6, x, 108-9;
supposed "pores" of Galen, 52, 62, 65-6;
systole and diastole, 64-5, 109;
valves of, ix, 202, 204, 206-7, x, 332;
work of, how measured, ix, 213-14
Heart Beat, ix, 202-3;
adrenalin effects, 171, 172, 209;
chemical theories of, x, 84;
control through nerve centers, ix, 168;
disturbances of, x, 333;
emotion effects, ix, 166, 209;
exercise effects, 168-9, 207, 208-9, 261-2;
rate of, 203, 204-5, x, 334;
rate increased by heat, 251;
rate in infants, ix, 347;
sounds of, 205-6;
variations in rate and vigor, 207-10
Heartburn, ix, 232

Heart Disease, atmospheric conditions best for, x, 241;
digitalis in, 333, 383;
early ignorance, xvi, 180-1;
modern therapy of, x, 382-3;
rheumatism and, 224;
valvular, 332
Heart Failure, x, 333;
symptoms accompanying, 340-1, 344
Heart Muscle, ix, 74-5, 84, x, 333-4;
"eight-hour day" of, ix, 210;
hypertrophy of, x, 331-2, 335;
nervous control of, ix, 207-335;
nervous control of, ix, 207-9
Heartwood, xiii, 24, 25, 26, 177 (fig.)
Heat, absorbers of, iv, 182;
absorption by colors, x, 309;
absorption by gases, viii, 309;
absorption by mixtures, iv, 175;
artificial, man's dependence on, ix, 308;
available supply in universe, iv, 193;
bacteria destroyed by, viii, 332;

"caloric" or "imponderable" theory, iv, 47, xvi, 125;
capacity, iv, 154-5;
change of state by, 151-3, 192-3;
chemical reactions and, viii, 12, 15, 53, 62, 95-6, 100, 308, 360;
chemical reactions hurried by, 310;

"closeness" due to, ix, 268-9, 270;
compression and, i, 26-7, 90, v, 126-8, 161, 351;
conduction and conductors of, iv, 138, 176-7, 178-9, x, 307, 308, 309;
convection of, iv, 139, 177-8;
demagnetization by, 253, vi, 34-5, 38, 117;
direction of flow of, iv, 190, v, 351, xvi, 135;
effects of, on bodies, iv, 144-59;
electrical production of, iv, 310-12, vii, 89, 337-8, 303-5, viii, 283-4;
electricity generated by, vi, 340
(see also Thermal Couples);
electromagnetic theory, vii, 371;
energy form, iv, 138, 140, 189;
"engineer" of physics, 50;
entropy, iv, 193;
expansion by, i, 27, iv, 134-5, 138, 140, 145, 151, viii, 25, 107;
forms, ii, 383;
from charcoal, viii, 186-7;
from foods, 361, 367, x, 269, 271;
from infrared waves, iv, 366;
from moon, ii, 200;
from radium, viii, 186-7;
from sun, ii, 169-71, iv, 181-2, 183, 194, ix, 25-6;
insulators, iv, 178, 184-5, vii, 307-8;
kindling temperature, viii, 53-4;
latent (see Latent Heat);
measurement for fuels and foods, viii, 360-1;
measurements, physico-chemical, 307-8;
measurement of quantity of, iv, 154;
mechanical equivalent of, (see Mechanical Equivalent);
mechanical (dynamical) theory of, iv, 48-9, 140;
molecular activity and, iv, 138-9, 140, viii, 25, 37-8;
motive power,
xvi, 135;
of earth's interior, iii, 108, 120-1, 160, 162, v, 178-81, xiv, 11-16, 31-2, 312;
of electric arc, iv, 311, vi, 280;
of electric lamp, vi, 268;
of volcanoes, iii, 106;
power from, v, 139-54, 351;
pressure of gases increased by, iv, 140;
production, electrical, 310-12;
production of, by friction, iv, 48-9;
production by mixtures, 174-5;
production by solidification, 160, 161;
radiant energy, vibration rate, ix, 114, 115;
radiation of, iv, 180-4;
reflectors of, 182-3;
resistance of charcoal, vii, 306;
rolling friction and, v, 204;
scientific meaning of, iv, 139-40;
sensation of, ix, 93, xi, 109, 113-14;
shrinkage in relation to, ii, 170 (see Lane's Law);
solvent action and, viii, 112;
specific, iv, 155-6, viii, 308-9;
"stuffiness due to", i, 321, x, 237-8;
temperature and, iv, 14-45;
thermodynamic laws, 189-90;
transmission through bodies, 176-9;
transmission through space, 180-4;
units, iv, 154, 189-90, vii, 369, viii, 374, x, 269;
universal presence, v, 345;
vacuums, v, 345-58;
wastage in engines, v, 155, 161, 165-6, 351
(see also Heat Waves, Temperature)
Heat Engines, iv, 192, 193-4, xvi, 135
Heat Equator, xiv, 347
Heating, dynamic, i, 90
Heating Systems, iv, 185-7;
dryness from, xiv, 353;
water advantages in, iv, 162
Heat Lightning, i, 148, vii, 205, 213
Heat Prostrations, ix, 316
Heat Regulators, vii, 87-8
Heat Stroke, x, 251-2, 274
Heat Thunderstorms, i, 138, 151, vii, 217
Heat Waves, vi, 119, 269, 270, vii, 371;
length and frequency, 260;
transmission of, iv, 180-4;
volcanic dust effects, i, 59
Heath Family, xiii, 202;
shrubs of, 274
Heavier-than-air Machines, v, 230-8;
principles, i, 286-9;
remarks on, vii, 76
Heberden, William, x, 104
Hebrew Language, xv, 162;
religious words from, 161
Hebrews, hemp fiber unknown to, xiii, 239;
ideas of insanity, x, 356;
unclean animals of, xii, 311
Hedgehogs, xii, 366, 367
Heidelberg Man, xv, 92, 93-5;
period of, 102
Heidelberg Race, xv, 96-7
Height, human, at morning and night, ix, 65;
rate of growth, 32;
of various races, xv, 38-9
Heights, oceanic, xiv, 286
Helicopter, i, 42
Heligoland, coast destruction, iii, 56
Heliocentric System, ii, 43-4;
known in Egypt, xvi, 69;
taught by Aristarchus, ii, 28
(see also Copernican System)
Heliometer, ii, 311
Helioscope, ii, 172-3
Heliotaxis, xi, 52-3, 61
Heliotropism, in hydroids, xii, 34
Helium, atmospheric, i, 11, 12, ii, 232;
boiling and freezing points, iv, 173;
critical temperature, 173;
density of, 113;
discovery, i, 12, viii, 302, xvi, 194;
frozen, v, 345;
liquefaction, i, 32, xvi, 194;
liquefaction temperature, v, 348;
molecular velocity in, iv, 133, viii, 185, 186;
monatomic, viii, 309;
production by disintegration, i, 12;
specific heat ratio for, iv, 156;
symbol and atomic weight, viii, 383;
use of, in balloons, iv, 108
Hellbenders, xii, 171-2
Hell Gate, tidal race of, xiv, 294
Hellgrammite, xii, 106
Helmets, modern, xv, 221
Helmholtz, chemical work, xvi, 142;
"Conservation of Energy," 181-2;
contraction theory, ii, 380;
medical work of, x, 131;
on Young, 97;
pupil of Muller, 118, 128;
sound studies, iv, 52, 233;
theory of life, xii, 9;
thermodynamic studies, xvi, 136;
theory of color vision, x, 96
Heloderma, xii, 207
Hematite, iii, 332, 356, 358, viii, 47, 156
Hemlocks, in class of conifers, xiii, 174;
foliage, 270-1;
planting conditions, 270;
poison, 250;
roots, 17;
in northern forests, xiv, 372

Hemoglobin, ix, 181-3, 184, 258-9, 275, x, 337;
deficiency in anemia, 337
Hemorrhages, blood transfusion in, x, 338;
low blood pressure in, 336;
prevention of, in surgery, 14, 148;
stopping of, ix, 179-81
Hemostat, x, 148
Hemp cellulose composition, viii, 254;
sources, xiii, 238
Hemp Plant, xiii, 238-9
Henna Dye, of Amatus, x, 58
Henry, induction unit, iv, 285

Henry, Prof. Joseph, i, 189, vi, 24, xvi, 191;
induction unit named for, iv, 285
Henry I, (England), arm's length of, iv, 45
Henry the Navigator, xiv, 309
Henry Mountains, iii, 139, xiv, 109, 227
Hens, language methods of, xv, 141
Heraclitus, on change, xvi, 79
Herbivora, xii, 300-31;
intestine length in, ix, 246
Herbs, antiquity, xiii, 319, 310;
in American summer forests, 368, 369;
as class of plants, 175;
fossil and existing species, 324;
garden, 289;
hairy covering, 104-5;
none among gymnosperms, 175;
planting table of annuals and perennials, 290-7;
stems, 23;
in temperate forests, 366

Hercules (constellation), star clusters in, ii, 336, 340;
stars moving from, 305

Herd-Instinct, x, 9

Hereafter, primitive conceptions of, xv, 332-6, 339, 340, 345

Heredity, x, 227-8;
diseases and, ix, 103, 181, 304, x, 234-5, 292, 303;
importance in human evolution, xvi, 47;
importance of knowledge of, x, 236;
laws and facts of, ix, 325-44, x, 228-34, xiii, 326-7, 331-4, xv, 22-3, 24, 27, xvi, 153-8;
social, xv, 30-1
Hering, Prof. D. W., author Physics, Vol. iv
Hering's Illusion, xi, 189
Hermit Crab, xii, 85
Hernia, operations for, x, 14, 41, 57

Hero, Greek scientist, inventions, xvi, 91, 92, 93;
mathematical work, 95;
steam turbine, v, 142-4, 148, xvi, 92, 93
Herodotus, Barton on, x, 20;
on fossil shells, iii, 14;
on Egyptian geometry, xvi, 68;
on Nile River, xiv, 71
Heroism, in crowds, xi, 326-7, 330
Herons, xii, 254-5
Herophilus, x, 23-4
Herring, xii, 154, 156;
limacina and, 19
Herschel, Caroline, ii, 104

Herschel, Sir William, astronomical work, ii, 15-16, xvi, 124-5;
discovery of Uranus, ii, 267;
father of descriptive astronomy, 139;
ideas of nebulæ, 368-9, 380;
knighting of, 254;
on habitability of sun, 252;
on proper motion of stars, 305;
picture of solar system, 162-3;
reflectors of, 103, 104;
studies of Galaxy, 352;
studies of Mars, 227;
studies of nebulæ, 358

Herschel, Sir John, dismantling of telescope by, ii, 104;
on spectrum lines, 112;
on Galaxy, 352;
studies of nebulæ, 358-9;
studies of star clusters, 336-7
Hertz, Heinrich, vi, 25, vii, 258, xvi, 191
Hesperornis, xii, 242
Hesperus, ancient name of Venus, ii, 191
Hessian Fly, i, 256
Hetchy-Hetchy Canyon, iii, 225
Heterodyne Receivers, vii, 278-9
Heterogeneous Rivers, xiv, 154-5
Heteromecic Numbers, xvi, 80
Hevelius, astronomer, ii, 57, 85;
telescopes of, 48, 99;
halo of, i, 374
Hewson, William, x, 88, xvi, 179
Hexane, viii, 206, 224
Heyl, Henry, v, 330

Hi and Ho, Chinese astronomers, xvi, 56-7, ii, 22

Hicetas, Greek astronomer, xvi, 81, 102
Hickory Trees, in American forests, xiv, 373;
in apetalae group, xiii, 190;
family, 191;
fertilization, 148;
leaves, 36-7;
leaf-bud protection, 34;
roots, 17;
sexes in, 46, 191
Hides, drying and tanning of, viii, 257
Hieroglyphics, Egyptian, xv, 172-4
High Blood Pressure, ix, 214, x, 334-6, 340
Highbrow, xv, 43

High Cost of Living, results in disease, x, 268

High Frequency Circuits, vii, 263
High Frequency Generators, vii, 290-1
Highlands, and lowlands, xiv, 213
Highlands-of-the-Hudson, iii, 188, 189

Highs, High Pressure Areas, i, 135-6, 137, 374;
movements, 134-5, 237;
weather significance, 236, 237;
winds in relation to, 125
(see also Pressure Areas)
Hill, James J., quoted, xi, 377
Hill, Prof. Leonard, i, 319, 320, 321, 322

Himalayas, animals of, xii, 288, 322, 325, 330, 337, 357;
forming of, iii, 236, xiii, 319;
glacial erosion in, xiv, 233;
height and importance, xv, 137;
impressiveness of, xiv, 9;
rainfall, i, 111;
rainfall on opposite sides, xiv, 355;
rhododendrons and azaleas in, xiii, 202;
rivers of, xiv, 167;
site formerly submerged, iii, 235;
sky line from Tibet, xiv, 234;
snow pinnacles, i, 117;
youthfulness, xiv, 96, 235
Hinds, xii, 317
Hindu Language, words from, xv, 161
Hindus, animal worship of, xv, 334;
astronomy, ii, 21, 26;
belief concerning trances, ix, 11, 17, 266-7;
cloud classifying by ancient, i, 97;
conception of earth, ii, 36;
crocodile veneration by, xii, 201;
geometry of, xi, 239;
in brown race, xv, 37;
marriage ceremonies of, 292, 293;
medicine and surgery of, x, 13-14, 57, 100, 123;
monkeys revered by, xii, 379
Hip Joint, dislocation of, ix, 67, 71
Hipparchus, ii, 10, 30-2, xvi, 90-1;
data gathered by, 94;
discoverer of precession, ii, 70;
novae observed by, 331;
star catalogue of, 300
Hippocrates, x, 18-22, 97, xvi, 95-6, 106;
aphorism of, x, 192, 379;
description of diseases by, 17;
humoral doctrine, 21, 98;
influence in Middle Ages, 31-2, 34, 36, 37;
"Oath" of, 18-19;
references to teachings, 55, 78, 154, 244, 289;
revival of teachings of, 44, 47, 48, 72, 73, 74

Hippopotamus, xii, 310;
trapping of, xv, 225
Hiqua, xii, 74
His, Wilhelm, x, 131
Histology, defined, xiii, 75
History, beginnings of, xv, 322, xvi, 51;
climatic influences, xiv, 29, 357-9, 361-2, xv, 123;
crowds and individuals in, xi, 333;
emotions in, 130;
geographical influences, xiv, 10, 30-1, 191-7, 239-45, 249-50, 279-82, 305-11, xv, 122-3, 136-9;
poetry and, 323-4;
sentiments the moving force, xi, 150;
suggestibility and records, 310;
warriors and artisans in, v, 15
Hoang-ho, shifting of courses, xiv, 184
Hoarfrost, i, 121, 258, 374
Hoatzin, xii, 241
"Hobble-Skirt" Cars, vii, 184
Hoe Printing Press, v, 301, 379, 381
Hoffmann, Friedrich, x, 85-6
Hogs, descent of, xii, 310;
embryological development, xv, 54, 55;
feeding garbage to, viii, 330
Hohenbergia, leaves, xiii, 106
Hohenheim, Aureolus von (see Paracelsus)
Hoists, in power plants, vi, 353

Holland, commercial history, xiv, 262, 280-1, 310;
low elevation of, 247;
rain-deposited salt, i, 60;
vaccination in, x, 103;
windmills, i, 37;
Zuider Zee of, xiv, 45-6
Holland Submarine, v, 382
Holly, American, xiii, 367
Holmes, Dr. Oliver Wendell, x, 114;
anesthetics named by, 125;
"goodly company" of, 134;
puerperal fever studies, 114-15, 122;
quoted, on therapeusis, 75
Holmium, symbol and atomic weight, viii, 383
Holothurians, xii, 23
Holyoke, Mount, xiv, 111

Home, electrical appliances in, iv, 10, vii, 73-90;
electric wiring, 67-8;
lighting and lighting systems, vi, 274-8, vii, 68-72, 75

Homer, historic value of poems, xv, 323-4;
medical references in, x, 16-17;
on blood showers, i, 55;
on the loadstone, vi, 29
Hominy Block, xv, 238-9
Homogeneous Rivers, xiv, 154
Honey, as food, ix, 292;
purpose in flowers, xiii, 124, 126, 142-3, 184;

"showers" of, i, 357

Honeydew, on plants, i, 351-2, 357

Honeysuckle, Italian, fertilization, xiii, 142-3;
leaf arrangement, 38;
tendril movement, 111
Hood, Mount, beauty of, xiv, 315;
cone of, iii, 226, xiv, 100-1, 225
"Hoodoo Country," xiv, 105
Hoofed Animals, xii, 300-31;
evolution, iii, 299, 300
Hooke, balance spring invention, v, 65;
geological work, xvi, 126;
light theory, 137;
microscope invention, x, 67;
microscopic work, xvi, 112;
on protoplasm, 166
Hooker Telescope, ii, 148, 156, 157-8, 159-60
Hookworm, campaign against, x, 171, 174-5;
parasite of, 199, 201;
in tropics, xiv, 357
Hookworm Anemia, x, 337
Hoosac Tunnel, drills in building, i, 27
Hope, physical effects, xi, 339
Hopkins, Dr. A. D., i, 255, 256, 367
Hop-vines, xiii, 27, 111
Horizontal Rainbows, i, 177

Hormones, ix, 170, 171, 189, 303, x, 320, 331, 347;
disease poisons as, ix, 178
Hornbeam, family, xiii, 193;
European, 271-2
Horneblende, iii, 321;
chemistry of, viii, 193
Horned Screamers, xii, 256-7
Horned Toad, xii, 204, 206
Horner, William, x, 116
Horn Gaps, vii, 17-18
Horns, in cattle family, xii, 324-5, 328;
of deer, 316
Horns (musical), from shells, xii, 74;
origin of, xv, 317;
sound production by, iv, 239-41
Horrocks, Jeremiah, ii, 58
Horseback Riding, as exercise, x, 304, 317
Horsechestnut Tree, dense shade, xiii, 86;
in landscaping, 271-2;
leaf-bud protection, 34;
stipules absent, 34
Horse Latitudes, i, 129, 374, xiv, 349

Horsepower, defined, iv, 80, vi, 83, 84, vii, 369;
electrical equivalent, vi, 84-5;
erg and calorie equivalents, vii, 382;
men's labor in, iv, 311;
thermal equivalents, v, 350-1
Horsepower-hours, iv, 80
Horseradish, aconite and, xiii, 252;
in mustard family, 197;
origin, 223
Horses, xii, 306-7;
automobiles and, v, 215;
class of, xii, 300;
cost of work, vii, 224-6;
diphtheria antitoxin from, x, 297;
domestication of, xv, 197;
ear movements, of, ix, 82, 117;
fear in, xi, 136;
geological history, iii, 299-300;
pictured in ancient art, xv, 112, 114, 116;
surra disease of, x, 168;
young of, ix, 346
Horseshoe Magnets, iv, 250, vi, 34, 45, 333

Horsetail Plants, iii, 251, 254, 256, xiii, 308-9, 314, 317, 323

Hoses, force, vi, 47-9;
rate of flow, 70-1
Hospitals, disease germs of, i, 325-6;
rise of modern, xvi, 184;
"Sunday temperatures" in, xi, 140
Hospital Tanks, v, 120
Hot Air Heating System, iv, 185
Hot Baths, ix, 322, x, 311-12, 383;
after eating, ix, 313;
cold sensation on entering, 93;
therapeutic uses of, x, 311, 383
Hot Climates, clothing for, x, 307, 308;
oiling of skin in, 311

Hot Springs, occurrence and explanation, iii, 128, xiv, 143-5;
plant life in, xiii, 299;
proof of earth's internal heat, xiv, 12;
travertine deposits, 146
Hottentots, hair of, xv, 38;
marriage by purchase among, 284
Hot-water Bottle, iv, 162-3
Hot Water Heating System, iv, 185-6, 187
Hot Water Plants, xiii, 299, 300, 301
Hot Waves, i, 374
Hot Winds, i, 134, 374
Hotchkiss Machine Gun, v, 365
Hotels, color lighting, vi, 274-5
House-breaking, of children, xi, 251-2
House Meters, vii, 174-7
Houses, dry air of, xiv, 353;
electric wiring, vii, 65-8;
evolution of, xv, 266-8
Howard, Luke, i, 97-8
Howe, Elias, sewing machine, v, 284, 379
Howitzers, v, 368-9
Huanacos, xii, 313
Huckleberry, growth of, x, 229
Hudson River, course, iii, 234, 245;
estuary of, xiv, 40;
locating rock under, v, 263-4;
mouth, xiv, 25, 270;
Palisades (see Palisades of Hudson);
sediment in channel, 268;
submerged channel, iii, 37 (fig.), 78, 234, xiv, 25, 287;
superimposed stream, iii, 233

Hudson River Valley, drowned character, iii, 38, 77-8, xiv, 25, 40, 255;
origin, iii, 232;
section of, 138 (fig.)
Hue, of colors, xi, 90
Hughes, D. E., vi, 26;
coherer of, xvi, 191

Human Energy, consumption in life processes and work, viii, 367;
daily expenditure in calories, ix, 297;
efficiency in use of, 296, 306;
food sources and requirements, viii, 334, 349, 350, 359, 361, ix, 289-301;
from foods, calculation of, x, 269-70;
per cent used, xi, 264;
Ostwald's imperative, 257;
production in kinetic system, 60-1
Humanists, "medical," x, 45

Human Life, temperate zones most favorable, xi, 51;
temperature limits, v, 348, ii, 243
(see also Life)
Human Race, cradle of, xvi, 46-7;
grouping tendency of, x, 9;
improvement by selection, xvi, 157
Humanistic Period, xvi, 86
Human Voice, range of, ix, 99 (see Voice)

Humboldt, Alexander von, discovery of orchid insect, xiii, 48;
geological work, xvi, 170, 171;
on the Ghor of Syria, xiv, 121;
on thunder at sea, i, 193;
studies of electric eel, vi, 16
Humboldt Current, xiv, 305
Humboldt Range, iii, 214
Humidifying Systems, i, 78
Humidity, i, 76, xiv, 353-4;
absolute and relative, i, 76-7, 375, xiv, 352-3, 354;
atmospheric, viii, 67;
body heat and, i, 317, v, 348-9, ix, 316, 317, x, 237, 251, xiv, 354;
danger in thunderstorms, i, 156;
heat prostration from, ix, 316;
measurement of, i, 78-9;
practical importance, 77-8;
ventilation and, 321, viii, 331, 332, ix, 268-9, 270, x, 237

Hummingbirds, xii, 269;
colors of, 245;
family of, 267;
plant fertilization by, xiii, 144
Humor, psychology of, xi, 350-7
Humoral Doctrine, x, 21, 28-9, 69, 98, 380
Humped Cattle, xii, 330

Humphreys, Dr. W. J., i, 58, 59, 113, 152, 153, 155, 172

Humus, formation of, viii, 340, 341, 346-7
Hungary, loess deposits, xiv, 72;
plains of, xiii, 373, xiv, 217;
stone implements of ancient, xv, 109
Hunger, "best sauce," ix, 242;
food regulation by, 299;
impulse of, in civilization, xv, 185-204, 273;
sensation of, ix, 87-8, 231, xi, 65-6, 67, xv, 65;
sense of, in infants, ix, 349-50;
sleep and, xi, 290
Hunger Strikes, water in, x, 275
Hunt, T. Sterry, xvi, 190
Hunter, John, x, 93-6, 97;
electric eel studies, vi, 16;
Jenner pupil of, x, 94, 99;
Virchow compared to, 129
Hunter, William, x, 92-3, 94
Hunter's Moon, ii, 196

Hunting, primitive methods and devices, xv, 222-8

Hunting Dog, African, xii, 345
Hunting Dogs, heart in, x, 332
Hunting Stage, xv, 187, 192-6;
equality of members in, 376;
leaders in, 366;
polygamy in, 287
Hurdy-Gurdy Wheel, v, 77
Huron, Lake, size, xiv, 204
Hurricane Cliffs, xiv, 124
Hurricane Grass, xiii, 344
Hurricanes, i, 136, 375;
electrification by, vii, 212-13;
handling of ships in, i, 277-8;
warnings in Caribbean Sea, 282, 309
Hurry, modern spirit of, xv, 12
Hussey, Obed, v, 244-5, 246, 247, 249, 379

Hutton, Dr. James, geologist, xvi, 126, 169-70

Huxley, gorilla studies of, xv, 57;
on herring, xii, 156;
work of, x, 136, xvi, 140-1, 142, 182
Huygens, as astrologer, ii, 21;
Kepler's Laws and, 61;
light theory, xvi, 119;
mechanical method of, iv, 11;
micrometer invention, ii, 58;
on planetary pull, 63;
on rings of Saturn, 54, 57;
pendulum clock invention, v, 65;
studies of Mars, ii, 227, 228;
studies of nebulæ, 357;
telescopes, 13, 57, 99
Hyacinth, xiii, 120, 184
Hyacinth Stone, iii, 341
Hyades, ii, 341-3
Hyalite, iii, 335
Hybrids, defined, ix, 334, xiii, 147;
transmission of characters, ix, 334-7, x, 231-2, 233, xiii, 332, 333

Hydra, fresh water, xii, 33-4
Hydraulic Jets, v, 88 (see Water Jets)
Hydraulic Machinery, v, 97-108

(see also special heads, as Cranes, Elevators, etc.)

Hydraulic Press, v, 97-100, 376;
mechanical gain in, iv, 41
Hydraulic Ram, v, 84-6
Hydriodic Acid, formation of, viii, 95-6
Hydro-acids, viii, 98, 114, 377

Hydrocarbons, and derivatives, viii, 51-2, 205-40;
molecular complexity and physical state, 298;
oxygen affinity for, 36;
substitution phenomena, xvi, 162
Hydrochloric Acid, viii, 86-7, 115;
action on cellulose, 255;
in gastric juice, x, 320, 325, ix, 234-5, 236, 237-8;
metal tests by, viii, 288;
production, 87, 105, 275, 277;
solubility in water, 111;
test for, 285

Hydroelectric Plants, v, 79, 83, vi, 351-2, 361-78;
on farms, vii, 233-4;
use of alternators, vi, 215;
(see also Power Plants)

Hydroelectric Power, called "white coal," v, 76;
in Switzerland, xiv, 242
Hydrogen, viii, 18, 29-33;
affinity strength, 128;
affinity for halogens, 85, 86;
atmospheric, i, 11, 192, ii, 232;
atomic weight and symbol, viii, 383;
atomic weights based on, 33, 92;
basic element, Prout's hypothesis, 177;
boiling and freezing points, iv, 173;
compressibility and volume, 143;
critical temperature and pressure, 173;
density of, 110, 113;
diffusibility of, viii, 108;
discovery, xvi, 120;
elimination from body, viii, 353;
explosions of, 33, 62;
flame of, 57, 58, 59-60;
increasing demand for, vii, 321;
in acids, viii, 114;
in organic compounds, 64, 204;
in plants, 336-7, 340-1;
in proteins, 351;
in water, weight and volume, 39-40;
liquefaction of, iv, 171, 191;
melting point, 162;
molecular speed, viii, 24, iv, 133;
percentage in coal series, iii, 345;
plant uses and sources, xiv, 64-5;
positive ionization, viii, 122;
preparation, 30-3, 102;
sound speed in, i, 192;
uniqueness of, viii, 182-3;
use of, in balloons, iv, 108;
valence basis, viii, 93;
valences to, 178, 179-80;
weight, iv, 110

Hydrogen Compounds, viii, 29, 36, 41, 51-2, 68-70, 205-40

Hydrogen Cycle, viii, 334, 350
Hydrogen Peroxide, viii, 41, 97;
bleaching by, 86, 256
Hydrogen Sulphide, viii, 77-8;
in metal tests, 288;
solubility in water, 111
Hydrogenation, viii, 232, 247, 377
Hydroids, xii, 18, 23, 33-7;
regeneration in, 170
Hydrology, problems, vi, 365-7
Hydrolysis, viii, 39, 217-18, 377;
by enzymes, 357, 358;
in cement setting, 280;
ionization and, 120
Hydrometers, iv, 113, vi, 147
Hydrophobia, Pasteur's work on, x, 142-3;
reduction of mortality in, 217
Hydroplanes, v, 192;
of submarines, 197-8
Hydrostatic Pressure, v, 95-6
Hydrotherapy, x, 383
Hydroxides, viii, 93, 377;
bases as, 115;
commercial preparation, of, 276;
metals found as, 130, 131, 198

Hydroxyl Derivatives, viii, 210, 212-14, 215, 218

Hydroxyl Group, viii, 377;
in bases, 115;
boiling point raised by, 299;
negative ionization, 122;
solubility, 112
Hyenas, xii, 351-2
Hygiene, among early Jews, x, 15;
daily applications, xvi, 15;
instruction in, remarks on, x, 282-5;
mental, xi, 368-82;
personal, disease prevention through, x, 302-17

Hygrometers, i, 78-9, 375;
invention, 68-9
Hygroscope, i, 375
Hymenoptera, xii, 124-6
Hyperfunction, defined, x, 348
Hyperopia, ix, 113
Hypersensibility, x, 212-15
Hypnotism, xi, 311-22;
use in medicine, xvi, 185-6
Hypo, of photography, viii, 140, 172
Hypofunction, meaning, x, 348
Hypophysis, (gland), x, 347, 352
Hysteresis, vi, 192, 213-14;
in motors, 225;
in transformers, 316
Hysteria, x, 360-3
Ianthena, xii, 19
Iatrochemical School, x, 69-70
Iatrophysical School, x, 69, 70-2
Iberian Racial Group, xvi, 49
Ibervillea, xiii, 106-7
Ibexes, xii, 325-6
Ibises, xii, 254, 255-6
Ibn-Yunos (Jounis), ii, 38, 210
Ice, ancient use in refrigeration, v, 349;
artificial, iv, 188, v, 349-50, 354-8, viii, 69-70;
color of, 40;
comparative heat, v, 345;
cooling by, iv, 178, v, 346;
density of, iv, 149;
disadvantages in refrigeration, vii, 230;
erosion by, (see Glaciers);
expansion of water in, viii, 38;
heat conductivity, iv, 179;
keeping of, v, 346, 349;
melting point and requirements, iv, 152, 161, 162;
melting point, pressure effects on, 163, 164, 164-6;
mixture with salt, temperature resulting, 175;
mixture with water, temperatures obtained, 160-1, v, 353-4;
regelation of, iv, 164-6;
specific gravity, iii, 321;
specific heat of, iv, 155;
temperatures at different pressures, v, 345;
transformation of snow into, iii, 59-60;
warming of, iv, 151-2

Ice Age, Great Quaternary, iii, 236-48, xv, 72-6;
antiquity of, xiii, 209, 322;
lakes formed, iii, 143-51;
man during, 302, 303, xv, 102;
Mississippi Valley remains, iii, 35;
moraines left by, 67-8;
sea level in, 83;
subsidence of land in, 80;
Yosemite Valley formed in, 48, 64
(see also Glacial Epoch)
Ice Age, Permian, iii, 203-4
Ice Ages, theories of, iii, 247-8;
volcanic dust theory, i, 58
Icebergs, submergence of, iv, 149
Ice Breakers, gyroscopes on, v, 342
Ice Caps, iii, 60, 61;
of Greenland and Antarctica, xiv, 55
Ice Clouds, i, 92-3, 103;
halos produced by, 177
Ice Dam Lakes, iii, 143-4, xiv, 201
Ice Crystals, i, 115-16;
halos from, 177, 178, 182-3
Ice Fogs, i, 95-6
Ice Houses, insulation method in, iv, 178
Iceland, discovery and settlement, xiv, 261;
fault displacement in, 39;
foxes of, xii, 344;
future manufacturing center, v, 173;
ice caps, iii, 61;
low pressure area, i, 361;
volcanic eruptions, 57, 59;
volcanic formation, xiv, 277, 289, 316
Icelandic Language, xv, 162
Iceland Spar, iii, 325;
effect on light, 319, iv, 354
Ice Needles, i, 92-3, 96
"Ice Pavement," xiv, 56
Ice Rain, i, 107, 375
Ice Saints, i, 363, 375
Ice Sheets, iii, 60, 61-2;
of Great Ice Age, 237-42, xv, 74-6
Ice Storms, i, 108
Ice Water, drinking of, ix, 229;
temperature of, viii, 38
Ichneumon Flies, xii, 125
Ichneumons, xii, 352
Ichthyornis, xii, 243
Ichthyosaurs, iii, 286-8, xii, 182, 202
Idaho, lava formations, xiv, 102, 103, 318;
mining products, iii, 362-3, 368
Idaho Fire (1910), i, 57
Ideal Metal, resistance, vi, 77
Ideas, psychological meaning, xi, 201-2

(see also Association of Ideas, Dissociation, Repression)

I-em-hetep, x, 11
Igneous Rocks, iii, 13, 379, xiv, 17-18;
common modes of occurrence, iii, 102 (fig.);
illustrations (Pl. 8, 9, 10);
intrusive and extrusive, xiv, 105;
intrusions in mountain ranges, 228, 230, 232-3, 234;
jointing in, 129-30;
land forms in, 44, 99-113;
oldest by nebular theory, iii, 160;
soils from, 28;
volcanic and plutonic, 106, 110, xiv, 99-100
Ignis Fatuus, i, 346-9, 375
Ignition, electric, vii, 369;
in automobiles, 130-41, 369;
in firearms, viii, 145;
temperatures of, 53-4
Iguanas, xii, 207;
boas and, 216;
color of, 204;
spiny crest of, 204
Ilkhanic Tables, ii, 39
Illinois, coal beds, iii, 199;
prairies of, xiv, 373, 383
Illinois River, sewage effects, viii, 326
Illuminating Gas, acetylene, viii, 60, 231;
burning of air in, 55, 56;
flame of, 57-9;
production, 46, 47, 252;
requisites, 60;
transfusion of blood in, poisoning from, x, 338

(see also Gas Lighting)
Illumination, art of, vi, 273;
measurement of, iv, 350-2;
unit of intensity, vii, 368
(see also Lighting, Lighting Systems)
Illusions, x, 358
(see also Hallucinations)
Illusions, Optical (see Optical Illusions)
Ilopango, Lake, draining of, xiv, 198
Images, formed by reflection, iv, 335-7;
formed by refraction, 337-9;
formation of, ix, 106-9;
real and virtual, iv, 335, 338, 339
Images (psychology), xi, 218-22
(see also After-Images)
Imagination, xi, 218-27;
due to conditioned reflexes, 202-3;
in science, xvi, 58-9
Imbeciles, reflex action in, xi, 36
Imhoff Tanks, viii, 328
Imitation, education by, xv, 66-7;
in language, 153-4;
instinct of, xi, 56;
suggestion and, 304

Immunity, against disease, ix, 179, x, 204-12;
racial, xv, 48-52

Impedance, in alternating currents, vi, 170, 171;
in oscillating circuits, vii, 289
"Imponderables," iv, 47
Impressions, first, xi, 211-12

Impulsiveness, of motor type men, xi, 157, 158-9;
will and, 264
Inanition, x, 275-7, 279
Inattention, xi, 25, 236
Inbreeding, in plants, xiii, 119-20

Incandescent Bodies, spectra of, ii, 112-13, iv, 360-3

Incandescent Lights, iv, 311

Incas of Peru, civilization in temperate climate, xv, 123;
corn in tombs, xiii, 212;
hunts of, xv, 222;
quipus of, 165, 166, (fig.)
Inclined Plane, iv, 90, v, 35-41;
primitive use of, iv, 24

Index of Refraction, in chemical analysis, viii, 310

Index Plants, i, 255
India, aborigines in black race, xv, 37;
aconite used as poison, xiii, 252;
adjutant bird of, xii, 255;
aerial photographic service, i, 46;
ancient astronomy, ii, 25, 26, xvi, 57;
ancient meteorology, i, 68, 213;
ancient science, xvi, 54, 62;
ancient sun-worship, ii, 23-4;
animals (carnivora), xii, 337, 340, 344, 345, 359, 365;
animals (herbivoral), 302, 303, 305, 308, 320, 327, 328, 330;
artificial ice in ancient, v, 349;
banana plants, xiii, 216;
betel nut, 254;
brontides, i, 195;
bubonic plague in, x, 164, 165;
Catalan forges in, v, 315;
cinnamon growing, xiii, 264;
civilization and climate, xv, 123;
coco palm of, 125;
copra production, xiii, 220;
cotton production, 237, 238;
cradle of human race, xvi, 47;
crocodiles of, xii, 199, 201;
deer-hunting in, 365, xv, 223;
dust whirlwinds, i, 60;
earthquake of, xiv, 333 (see Great Indian Earthquake);
famines, xiii, 214;
forests, government-controlled, 372;
former trade routes, xiv, 307, 309;
glacial deposits, iii, 203;
hailstorms, i, 120;
Himalayas as protection to, xv, 137;
ideas of eclipses, ii, 209;
jungle fowls of, xii, 261;
jute production, xiii, 241, 243;
monkeys of, xii, 379;
monsoons, importance, i, 66-7, 131, 218, xiv, 350-1;
monuments and records, ii, 24;
music of, xv, 314
native marriage customs, 282;
peoples and civilization, xvi, 53-4;
pipal tree, xiii, 108;
plains of, xiv, 47, 217;
polyandry in, xv, 286;
poppy growing, xiii, 253;
quinine production, 251;
rainy seasons, xiv, 352;
rattan palm, xiii, 27, 361;
religious cults, ix, 266;
religious philosophy, xi, 116;
rice in, xiii, 213;
rivers of, xiv, 195-6;
rubber growing, xiii, 247, 248;
serpents of, xii, 214, 219, 228-9, 231;
smallpox inoculation in, x, 100;
sugar production, xiii, 215;
Suttee in, xv, 335;
tarpon of, xii, 154;
tea cultivation, xiii, 228;
telegraph plant, 114;
tobacco production, 258;
tortoises of, xii, 191;
weather conditions, distant causes, i, 241;
wine palm, xiii, 53
(see also Hindus)
Indiana, glacial drift in, xiv, 69, 170;
limestone quarries, iii, 371-2;
prairies of, xiv, 373
Indian Corn, American origin, xiv, 382;
history and uses, xiii, 211-13;
prop roots, 20 (fig.);
stem, 183
(see also Corn)
Indian Meteorological Dept., i, 241
Indian Ocean, extent of, xiv, 22;
monsoons of, 350-1;
salt in, viii, 139;
sharks of, xii, 146;
tortoises on islands of, 192
Indian Pipe Plant, xiii, 99, 202

Indians, American, acuteness of vision, vi, 272-3;
arrows of, xv, 196 (fig.);
basket-weaving of, 248;
bows of, 214 (fig.);
canoe-making, 262;
cattle-raising stage absent, 187, 199;
chiefs, 364;
color of, 37;
corn-growing, xiii, 211-12, 212-13, xv, 201 (fig.);
dogs used in hunting, 223;
domestic animals lacking to, 199;
dramatic ceremonies and plays of, 305-6, 306-7, 308;
fear of pogonip, i, 96;
fertilizing method of, xv, 202;
guardian spirits, 348-9;
hair of, 37;
Happy Hunting Grounds of, 333;
"hiqua" money of, xii, 74;
language deficiencies, xv, 144;
lodgepoles of, xiv, 374;
long houses of, xv, 267;
marriage practices, 283-4, 284;
measles and, 48;
mineral springs used by, xiv, 145;
note to Jenner, x, 103;
painting of faces by, xv, 256;
pottery of, 250 (fig.), 252 (fig.);
prairie firing, xiii, 374;
prayers of, xv, 346-7;
religious beliefs, xvi, 44;
signal fires, xv, 165-6;
sign language, 148-51;
sign writing, 172, 173 (fig.);
stone pestles of, 238 (fig.);
tents of, 266;
tomahawks of, 208;
tree-felling by, 262;
tribal morality of, 374;
tribes in mountains, 129-30;
unions among, 363;
weaving of, 247 (fig.), 301 (fig.)
(see also South American Indians)
Indian Summer, i, 361-2, 363, 375
India-rubber, elasticity of, iv, 36;
low temperature effects, i, 31
Indicators, chemical, viii, 114, 294, 378
Indigestion, causes and results, ix, 238-42;
from worry, 165, 167;
mental effects, xi, 369-70
Indigo (color), ix, 115;
changed to indigo white, viii, 259
Indirect Lighting, vi, 277, vii, 70
Indium, symbol and atomic weight, viii, 383

Individuals, differences in, ix, 327, xi, 152-9;
influence of, in history, 333;
inheritance of extreme characters, xvi, 154;
moral control, 48;
new species from variations of, xiii, 325, 328-9;
psychology in crowds, xi, 324, 325-30;
transmission of acquired characters, ix, 325-6

Indo-China, food plant source, xiii, 221;
python of, xii, 214
Indo-Chinese, in yellow race, xv, 37
Indo-European Languages, xv, 161, 162
Induced Currents, iv, 303-9
Induced Voltages, vii, 370
Inductance, defined, vi, 91, 166;
in direct and alternating currents, 166-7, 169;
flashes caused by, 102, 312;
in induction motors, 248;
in telephone lines, vii, 104;
in wireless communication, 264, 286-7, 289, 293-5, 296-7

Inductance Coils, vii, 105, 264, 266, 267
Induction, charging by, vi, 290-2, 297-301;
discovery, 22, 23;
electrification by, iv, 260;
electrodynamic and static, vii, 370;
law of, vi, 313;
Lenz's Law, vii, 371;
magnetization by, iv, 243;
self, vii, 375;
unit of, iv, 285
Induction, Proof by, xi, 242

Induction Coils, iv, 265, 303-5, vii, 364, 370;
in automobiles, 133-4;
in electrotherapy, 242-4, 245;
in wireless telegraphy, iv, 313, 314

Induction Machines, vi, 292, 298-301, vii, 245

Induction Motors, vi, 241, 242-56;
in motor-generator sets, 332, 342
Induction Regulators, vi, 328-9, 346
Inductivity, vi, 293-4

Industrial Plants, advantages of electricity, vii, 51-3;
lighting, 52;
wiring, 57
Industrial Psychology, xi, 358-67
Industry, electricity in, vi, 195-6, 381;
energy sources, viii, 267-8;
metals of, 154;
motors most used, vi, 241;
science in, xvi, 9-10;
water power and, vi, 352
Inertia, defined, vi, 90-1, vii, 370;
examples of, iv, 35, 62, 66, 67, v, 148, 234, 336-9;
in electrical currents (see Inductance);
in perception errors, xi, 184, 189;
law of, ii, 62, iv, 19-20, 61-2;
of æther, vi, 120;
of ear, xi, 105;
of sense organs, 71
Infancy, period of, x, 283, xvi, 79
Infantile Paralysis, germ of, x, 200, 202;
immunity to, 207
Infants, ape-like structures in, xv, 61;
bodily condition and care of, ix, 345-52;
clothing of, x, 309;
grasping reflex, xi, 40-3;
heart rate in, x, 334;
learning to breathe, xi, 36-7;
learning to fixate, 39-40;
learning to swallow, 38;
milk modifications, viii, 363;
nervous system in, ix, 344, 348-9;
new-born, free from germs, x, 201;
new-born, weight of, ix, 31;
periodic breathing in, x, 340;
skull capacity in, xv, 40;
space perceptions, xi, 162-3, 166
Infections, ix, 177-8, x, 193;
by germs, x, 193, 204;
body resistance to, 197-8, 203-12;
body resistance to, ix, 177-9, 185-6;
exhaustion from, ix, 59-60;
focal, x, 198-9, 218-26;
in surgery, prevention of, 14, 123, 145-7, 181-3;
local and general, 198;
"portals" of, 198, 201-2;
pus, ix, 186-8
Infectious Diseases, x, 193-226;
atmospheric electricity and, i, 330;
danger from, 326;
heredity and, x, 234-5;
immunity to, 204-12, ix, 179;
infants' susceptibility to, ix, 352;
pain in, 87;
Pasteur and Koch's work, xvi, 184;
prevention and treatment, x, 217-18, 285-302

(see also Antitoxins, Inoculation, Vaccination);
ticks as cause of, xii, 98;
transmission and history of various, x, 153-70

Infinity, meaning, xi, 191, 196
Inflammations, germ-produced, x, 195;
terms used to define, 30

Influence Machines, vi, 292, 298-301, vii, 372;
in therapeutics, 236
Influenza, x, 294-5;
from chilling, 306;
immunity to, 207;
present knowledge of, 153, xv, 48
Infra-red Rays, iv, 365, 366
Ingersoll, Dr. E., author Zoölogy, Vol. xii
Ingots, steel, v, 322;
"pipes" in, 323
Injections, subcutaneous, ix, 59
Injectors, of boilers, v, 140-2, 380
Ink, Acheson's, vii, 301
Innominate Bone, ix, 63 (fig.), 66-7
Inoculation, early practice of, x, 207;
for anthrax and rabies, 141-2;
for smallpox, 100-3
(see also Vaccination)
Inorganic, defined, viii, 378
Inorganic Chemical Industries, viii, 267-84
Inorganic Compounds, colors of, viii, 312;
solubility in water, 37, 111-12

Inorganic Matter, plant use of, viii, 339, 349, xiii, 14, 79, 81

Inorganic Nature, chemical inactivity, viii, 267

Insanity, definition and symptoms, x, 357-9;
former ideas and treatment, 11, 356-7;
increase of, xv, 27;
increase prevention, x, 235-6;
Pinel's treatment, 110-11;
primitive conceptions of, xv, 350, 353
Insecticides, arsenic, viii, 169
Insectivora, xii, 366-8;
lemurs and, 376
Insects, xii, 99-126;
capture of, by plants, xiii, 39-41;
classification, iii, 260, 276;
cold effects on, ix, 306;
evolution, iii, 20, 257, 279, xii, 104-7;
flower fertilization by, xiii, 48, 123-46, 318, xvi, 152-3;
fossil remains, iii, 16, 279-80;
hearing of sounds by, iv, 204;
jaws in, xii, 106;
larvæ affected by light, x, 253;
musical, xii, 109-10;
number of species, 99;
popular definition, 90;
primitive groups, 104-7;
protective coloration in, xv, 17-18;
reproduction in, xii, 104;
respiration in, 103;
structure of, 99-103;
studies of, xvi, 143-4;
tool-using by, v, 10-11
Inside Passage, xiv, 258-9
Insomnia, xi, 288-91;
caused by vasoconstrictor activity, ix, 218-19;
exhaustion from, xi, 59-60
Inspiration, as intuition, xi, 245;
Titchener on, 226
Instincts, defined, xi, 46-8;
fundamental, 49-56, xv, 185;
in man and animals, 65-6;
reflex nature, xi, 48-9;
self-preserving, x, 9-10, 282-3
Instrument-Shelter, i, 375
Instrument Transformers, vii, 44, 165
Insular Climate, xiv, 347
Insulation, importance, vi, 9-10;
in dynamos, 192, 211-12;
types of wire, vii, 58

Insulators, electrical, iv, 259, vi, 294-5, vii, 370;
pin and suspension types, 15-16
Insulators, heat, iv, 178, vii, 307-8
Insults, emotions from, xi, 150
Insurance, weather, i, 269-70, 344
Intake-Output Test, x, 379

Intellectual Processes, in brain, ix, 147-53, 154

Intelligence, artificial selection of, xvi, 154;
mental economy and, xi, 377;
instinct and, 46, 47, 50;
nervous organization and, 13
Intelligence Tests, xi, 359-60
Intemperance, arteries injured by, ix, 214
Intensity, electric, vii, 370
Intensity, of sounds, iv, 211

Interborough Rapid Transit Company, great alternators, vi, 216, 378-9;
synchronized plants, 384
Interchangeable System, v, 48-52, 53-4, 55-6
Interest, advertising value, xi, 345-6;
associations determined by, 203, 205-6;
attention and, 235-6;
fatigue and, 275;
in salesmanship, 341-2
Interference of Light, iv, 376-8
Interference of Sounds, iv, 218-22
Interferometer, ii, 151, 323

Interior Lighting Systems, vi, 275-8, vii, 68-72

Interior Wiring, vii, 51-72;
insulators in, 370
Interlaken, Switzerland, lakes at, xiv, 202
Internal Combustion Engines, v, 155-70;
in aeroplanes, 231;
in automobiles, 213;
in submarines, 199;
efficiency, securing of, xvi, 135;
Joule's equivalent and, 132-3
Internal Senses, ix, 86-91
Interoceptive Senses, xi, 63
Interpoles, of dynamos, vi, 190-1
Interurban Traction, vii, 181;
automatic substations, 192-3;
cars and motors, 186;
voltage drop, 189
Intestinal Stasis, x, 220
Intestines, ix, 233 (fig.);
development in black and white races, xv, 50;
emotion effects on, xi, 135, 137;
functions of, viii, 356-7, 358;
functions, operations, and disorders of, ix, 232-4, 236-8, 242-52, x, 325-9;
germs in, ix, 247-9, x, 193, 194, 201, 287-8;
infections through, x, 198, 220, 221;
in infants, ix, 346;
inflammation of, cause, x, 224;
length in animals and man, ix, 246;
mucous membrane, functions of, x, 347;
position in circulatory system, ix, 196 (fig.), 198;
smooth muscles in, 74, 160-1, 162
Intrenched Meanders, xiv, 165
Intrusive Rocks, xiv, 105
Intrusive Sheets (sills), xiv, 108
Intuition, xi, 245-6;
Bergson on, xvi, 196
Inventions, imagination in, xvi, 59;
inspiration and labor in, xi, 226;
method of great, xvi, 98;
misuse of ancient, v, 15-16, 111;
necessity and laziness in, 282;
production increased by, 17-18;
pure science preliminary to, iv, 44-5;
summary of mechanical, v, 376-84;
war as stimulus to, 12, 359-60, 375

Inverse Time Relays and Switches, vii, 37, 39-40, 41, 42

Invertases, viii, 357
Invertebrates, xii, 127;
age of, iii, 20;
largest, xii, 80
Invincible Armada, xiv, 280
Inyo Earthquake, iii, 225
Iodine, a halogen, viii, 18, 84-5, 86;
as antiseptic, 333;
atomic weight and symbol, 383;
classification place, 182, 183;
indicator uses, 294;
in seaweed, 197;
manufacture of, 274;
physical state and, chemical properties, 22, 297-8;
test of, 290;
thyroid secretion of, x, 351
Iodoform, viii, 52, 212
Ion-Counters, i, 142-3, 375
Ionic Reactions, viii, 119-25
Ionization, vi, 133-5, vii, 247, 248, 370;
defined, viii, 378;
electron theory, 188;
in electric precipitation, vii, 348-9;
of atmosphere, i, 142-4, 146, 150;
of solutions, viii, 119-25, 300-1;
origin of theory, 296, 300-1
Ionogens, viii, 122, 125, 378
Ions, iv, 382, vii, 370, viii, 378;
in electric batteries, vi, 133, vii, 247;
number in air, i, 142-3;
of solutions, viii, 120-4, 286-90;
origin of name, 124;
positive and negative, i, 142, vii, 247, 370
Iowa, glacial deposits, iii, 241;
gypsum deposits, 376;
loess deposits, xiv, 72;
porous rocks beneath, iii, 114;
soil of, xiv, 383;
wells, iii, 118, 119, 125
Ireland, Alpine invasion, xvi, 49;
coast formations, xiv, 24, 47, 249, 251, 257;
continental island in character, 273;
"Emerald Isle," 352;
eskers and drumlins, 59, 60;
former volcanoes, 318;
Ice Age in, xv, 74;
lakes of, xiv, 200;
lava plateau of, 104;
potato in, xiii, 218;
rainfall in, xiv, 41, 352;
scurvy and potato crop, x, 266;
snakes in, xii, 217
Iridescence, cause of, xii, 245
Iridium, viii, 173, 383
Iridocytes, xii, 135
Iris, xiii, 22-3, 57 (fig.)
Iris Family, xiii, 189
Irish, pre-Nordic, xvi, 49
Irish Language, xv, 162
Irish Potato, xiii, 218, 219
Irish School, of Medicine, x, 112
Irish Wakes, xv, 336
Iron, affinity strength, viii, 128;
antiquity of use, v, 314-15;
atomic weight of, viii, 180, 383;
body use of, ix, 184, x, 256;
cast and wrought, v, 316-17;
cast and wrought, viii, 157, 158, 159;
castings of, iv, 150;
density of, 111;
electrical conductivity, 283, vi, 77;
electrical positiveness, 59;
electrolytic refining, vii, 320;
expansion on solidifying, iv, 150;
expansion rate, 145-6;
extraction from ores, viii, 271;
fusibility, 384;
galvanized, vii, 318-19, viii, 155-6, 273;
heat conduction by, iv, 179;
importance, v, 314, viii, 156;
in blood, 354;
in chlorophyll, xiii, 79-80;
in earth's crust, iii, 308, viii, 19, 129, 192;
in earth's interior, xiv, 11;
magnetic, iv, 242, 243 (fig.);
magnetization, 243, 245, 251, 287-8, vi, 35-6;
melting point and requirements, iv, 162, 163;
metallography of, viii, 273-4;
meteoric, ii, 292;
meteoric, in deep sea, iii, 55;
ores and occurrence, 355-9, viii, 47, 130, 148, 156, 198;
ores, profitable, 197;
plant needs of, 337, 341;
properties of, 126-7, 154;
rusting, iii, 25, viii, 9, 13, 155-6;
sheet tin, 161;
shortness, hot and cold, iii, 356;
sound velocity in, iv, 201;
specific gravity of, 109, viii, 384;
specific heat, 308;
symbol, 383;
test for, 287, 288-9;
valences, 161, 189
Iron Age, xvi, 51;
tools of, 47
Iron Compounds, viii, 160-1
Iron Industry, history, xvi, 174-6;
processes in, v, 315-18, viii, 157-9, 273, 345

Ironing Machines, Electric, vii, 82-3
Iron Oxides, viii, 13, 156, 157;
in pigments, 265;
in rock decay, iii, 25, 27;
in soils, iii, 28;
removal in steel-making, v, 320;
rock coloring due to, iii, 25-6, 27, 44
Iron Pyrites, iii, 335, viii, 156, 198;
in wireless detectors, vii, 269
Irons, Electric, vii, 77
Iron Ships, floating of, iv, 104-5;
magnetization of, 254
Iron Structures, magnetization of, iv, 253
Iroquois, Lake, iii, 149, 150

Iroquois Indians, and Mohawk Valley, xiv, 194;
power of women among, xv, 295;
union in nation, 363
Irrationality of Dispersion, ii, 101
Irrigation, development of methods, v, 239;
in Egypt, 18-19, 178;
electrical methods, vii, 231;
in relation to critical periods, i, 250;
sewage disposal by, viii, 327;
snow sources, i, 118

Irritability (life), doctrine of, x, 86, 87, 88

Isallobars, i, 238
Ischia Earthquake, xiv, 339
Isinglass, iii, 334

Islands, classes, continental and oceanic, xiv, 271-9;
formed on coasts, 251-2, 256, 258;
historical importance, 281-2, xv, 137;
new volcanic, xiv, 319;
overpopulation of, 282;
plants of oceanic, xiii, 348;
tidal races produced by coastal, xiv, 294
Isobaric Elements, viii, 189
Isobars, i, 125, 375-6;
classification, 238;
spacing, 126;
winds in relation to, 126
Isohyet, defined, i, 376
Isohyetal Charts, i, 206
Isomer, defined, x, 137
Isomerism, defined, viii, 378
Isomorphism, viii, 313
Isothermal, defined, iv, 382
Isothermal Changes, in gases, iv, 156, 159
Isothermal Layer (atmosphere), i, 19
Isotherms, i, 206, 207, 376;
barriers to plants and animals, xiv, 364
Isotopic Elements, viii, 189
Israelites, "Cities of Refuge," xv, 369;
life of, 199
Italian Honeysuckle, xiii, 142-3

Italian Language, descent from Latin, xv, 160, 162;
musical terms from, 161
Italians, in Alpine group, xvi, 49
Italy, Adriatic coast, xiv, 252, 263;
aeronautical weather service, i, 230, 304;
Alps Mountains and, xiv, 244-5, xv, 138;
"blood showers," i, 55;
boric acid sources, viii, 90;
brontides, i, 196;
bubonic plague measures, x, 164;
buffalo use in, xii, 329;
earthquakes of, xiv, 332, 340-1;
former connection with Tunis, 291;
geographical changes in, 33;
hail-shooting, i, 341, 342, 343;
lakes, beauty of, xiv, 200;
lakes, breezes of, i, 132;
mercury production, iii, 370;
meteorological observations, i, 68-9, 213;
Napoleon's campaigns in, xiv, 244;
paper-making, v, 290;
rainfall, xiv, 358;
Renaissance and science in, ii, 12-13;
rice growing, xiii, 214;
sea captains of, xiv, 310;
volcanic power, v, 179-80;
in World War, xiv, 244-5, 252-3, xv, 138;
in World War, medical preparedness, x, 176
Itching, sensation of, ix, 92-3, xi, 109, 114
Ivory, elasticity of, iv, 36;
sources of, xii, 302, 303
Izalco Volcano, xiv, 321, 325
Jackals, xii, 339-40;
dogs and, 344;
ears of, 346

Jack-in-the-Pulpit, in arum family, xiii, 188;
flower, 52 (fig.);
leaves, 183 (fig.);
stems, 23 (fig.)
Jacks, Hydraulic, v, 100, 101, 124, 260
Jackson, Dr. Charles T., x, 124, 125
Jackson, James, x, 116, xvi, 185
Jacquard Loom, v, 280-2, 377
Jade, iii, 322-3;
pyroxene, 336
Jaguars, xii, 360-2
Jaguarundi, xii, 364
Jamaica Earthquake, cause, xiv, 340
James, William, on associations, xi, 204-6;
on attention, 232;
on emotions, 141;
on habit, 255-6, 256-7;
on instincts, 48;
on memory, 208;
on stream of consciousness, 193;
on will and action, 264;
on complexity of life, x, 244;
on seasickness, 242;
on outdoor treatment, 241;
pragmatic philosophy, xvi, 196

James, W. T., link motion invention, v, 208, 379

James, I. Harvey, physician to, x, 62;
of England, submarine trips, v, 196-7

James River Valley, N. D., wells in, xiv, 12, 139

Janet, Dr. P., x, 360-1

Janssen, Jules, astronomer, ii, 114, 127, 180-1;
station on Mt. Blanc, 142
January Thaws, i, 363, 376
Japan, Ainus of, xvi, 64;
beriberi in, ix, 35, x, 257;
brown bears of, xii, 336;
copper production, iii, 360;
earthquakes of, xiv, 332, 341;
earthquake studies in, 337, 342;
geology of, 125;
ginkgo tree in temples, xiii, 315;
goat antelope of, xii, 325;
historical development from insulation, xiv, 281;
idea of eclipses in, ii, 209;
octopod fishing, xii, 78;
railway bridges, earthquake construction, xiv, 342;
rice, xiii, 213;
tea cultivation, 228;
temperate rain forests, 372;
tidal waves, xiv, 337;
trees of, 377;
volcanic eruption effects, i, 57, 59
Japan Current, xiv, 304

Japanese, artificial immunity practiced by, xv, 49;
food and stature of, xiii, 172;
in yellow race, xv, 37;
tattooing among, xv, 258
Japanese Earthquake, iii, 94;
fault formed by, xiv, 334, 335
Jasper, iii, 337
Jaundice, cause of, ix, 243;
epidemic, x, 201

Java, ancient man-ape of, iii, 302, xv, 88-92;
bats and fruits of, xii, 370;
cinnamon production, xiii, 264;
continental island, xiv, 274;
tea cultivation, xiii, 228;
transplanting rice in, (illus.) 208;
zoölogy of, xiv, 274-5
Javelins, Roman, xv, 213
Jaws, bones and functions of, ix, 62-3;
deformities of, results, 228;
in aged people, 57;
in apes and men, xv, 62;
of primitive men, 91, 92, 95;
protruding, classification by, 43-5

Jealousy, absent in polygamous countries, xv, 288;
sentiment of, xi, 149-50

Jefferson, Thomas, on climatic changes, i, 201;
on standard muskets, v, 49;
vaccination interests, x, 102
Jelly-Fishes, iii, 259, 266-7, xii, 35-7;
coelenterates, 26;
phosphorescence of, 18, 19
Jenkins, C. Francis, v, 330
Jenner, Edward, x, 99-103, xvi, 126-7, 184;
love affair, x, 95;
pupil of John Hunter, x, 94, 99;
vaccination discovery, x, 100-2, 122, 207-8
Jerboas, xii, 289-90

Jesuits, meteorological services, i, 213, 223;
survey of China, xvi, 123
Jewelweed, seed dispersal, xiii, 56
Jewish Medicine, x, 15-16
Jews, of Asia and Europe, xvi, 64;
circumcision, untransmitted, x, 230;
history in relation to Ghor of Syria, xiv, 121;
immunity from trichina, xv, 49;
polygamy among, 289;
prepotency in crosses, x, 230
Jew's Harp, iv, 232
Jibon River, Salvador, xiv, 198
Jihar River, xiv, 185
John Daniel, orang-utan, xvi, 25
"John H. Grindle", (fish), xii, 152
John of Gaddesden, x, 41

Johns Hopkins Hospital and Medical School, x, 151, 172

Johnson, Prof. D. W., coast classification, xiv, 253;
on climatic changes, 361

Johnson, Samuel, compared with Paracelsus, x, 48;
on Heberden, 104

Johnstown Flood, iii, 31

John the Baptist, locusts and honey of, xv, 134

Joints, arm and hand, ix, 67;
diseases of, x, 224-5;
dislocation of, ix, 71;
fastening at, 70-1;
hip, 67, 71;
motion sense in, ix, 90;
muscles to move, 76-7;
sensations of, xi, 124-5, 128;
shoulder, ix, 66, 71

Joints, Joint Blocks (geology), iii, 23, 379, xiv, 128-30;
illustration, iii, 144 (Pl. 8);
residual cores, iii, 32 (Pl. 1);
topography and drainage effects, xiv, 130-3;
various examples, iii, 48, 49-50, 65
Joint Worms, xii, 125
Joliet, expedition of, xiv, 192
Joplin, Mo., mining district, iii, 362, 364
Jordan Engine, v, 294-5
Jordan River, base level of, xiv, 164
Jordan Valley, iii, 151, xiv, 118, 120, 167
Jorullo, Mexico, xiv, 320

Joule, electrical energy unit, iv, 284, 294, 310, 312, vii, 370;
used as heat unit, 369;
erg and calorie equivalents, 382;
work or energy unit, iv, 80

Joule, James Prescott, energy unit named for, iv, 284;
heat experiments of, 49-50;
mechanical equivalent of heat, xvi, 131-3
Joule-Thomson Effect, i, 30
Joy Stick, i, 299
Judæa, Wilderness of, xiv, 121
Judaism, development of, xv, 199
Jumping Hare, xii, 290
Juniper, a conifer, xiii, 174;
in landscaping, 270;
spread by buds, 340
Junker Engine, v, 163-4
Jupiter (planet), ii, 260-3;
atmosphere, 249, 261;
comet families, 271;
disturbing effect on asteroids, 258;
"great inequality," 87;
habitability of moons, 250;
life on, ii, 248-9;
lucid planet, 249, 261;
photographic studies, 132-3;
rotation period, 377;
satellites, 261-3;
satellites, discovery of, 54, 83, 94, 110, 267;
size and orbit, 162, 163;
weight, 76, 77
"Jupiter", U. S. collier, vii, 326
Jura Mountains, xiv, 93-4;
age of, 232;
folding of, 36, 93-4, 229-30;
little metamorphism in, 234;
streams of, 94, 95, 157, 167
Jurassic Period, iii, 213-14;
Age of Reptiles, xv, 71;
animal and plant life in, iii, 20, 255, 270, 276, 289, 295;
flies of, xii, 104
Juries, as crowds, xi, 326
Justifying (printing), v, 308;
on linotype, 310;
on monotype, 311-12
Jute, cellulose composition, viii, 254;
uses and production, xiii, 241-3;
economic importance, 208
Juvenile Water, xiv, 151-2
Kaaba of Mecca, ii, 284
Kaguan, Malayan, xii, 367
Kalahari Desert, xv, 133;
antelopes of, xii, 327
Kames, glacial, iii, 69-70
Kayaks, xv, 264 (fig.)
Kangaroo Mice, xii, 290
Kangaroos, xii, 278-80;
young of, 274
Kansas, ancient birds of, xii, 242;
former reptiles of, 202;
gypsum deposits, iii, 376;
locust plague of, xii, 109;
volcanic dust beds, xiv, 327
Kansas City, automatic telephony, vii, 92
Kant, excessive professionalism of, xi, 376;
nebular hypothesis, ii, 367-8, 380;
on structure of universe, 350, 352;
philosophy of, xvi, 111
Kaolin, iii, 333;
formed from feldspar, 25, 27, 373
Kapteyn Plan, ii, 353
Karnak, Temples of, ii, 25-6
Karst District, xiv, 150
Katathermometer, i, 319-20, 321, 376
Katmai, Mount, crater, iii, 101 (fig.), 102;
eruption, i, 59, iii, 102;
lake in crater, 155
Katydids, xii, 109-10;
Florida, 100 (fig.)
Kaye, John, x, 45
Keewatin Glacier, iii, 238-9
Keewatin Series, iii, 169

Kelvin, Lord, contributions to electricity, vi, 23-4;
on oscillatory circuits, xvi, 191;
on rigidity of ether, 137;
theory of life, xii, 9
Kelvin-Chetwynd Compass, vi, 41-2
Kelvin's Law, vii, 21-2
Kent's Cavern, England, xv, 77-83
Kentucky, "Blue-grass Region," xiv, 68;
"dark and bloody ground" of, 243;
glacial period in, 376;
non-glacial topography, 56;
underground streams, 149
Kentucky Blue Grass, xiii, 179
Kenya, Mount, glaciers of, xiv, 54
Keokuk Power Plant, v, 81-3, vi, 352

Kepler, Johann, ii, 14, 49-52, iv, 19, 95, xvi, 102-3;
as astrologer, ii, 21;
on comets, 83-4;
eclipse calculations, 216;
Galileo and, 53;
idea of moving bodies, 63;
new star seen by, 331;
on star distances, 350;
on sun's corona, 221;
Tycho Brahe and, 12
Kepler's Laws, ii, 49-52;
Newton's explanations, 62-6, 88, xvi, 115-16;
proved by Keeler's discoveries, ii, 121;
used in weighing planets, 75-6
Kerosene, viii, 51, 208;
combustion of, 52, 54, 57, 59;
soap and, 142;
used in mosquito campaign, x, 300
Ketones, viii, 225 (note)
Kettle Holes, iii, 144
Keyhole Nebula, ii, 355, 365
Key Instruments, xv, 318

Kidney Diseases, atmospheric conditions best for, x, 241;
blood pressure and, 335;
Bright's Disease, 112, 346;
from focal infections, 224, 225;
nephritis, 344-5, 346;
salt in, 256;
therapy of, 382-3

Kidneys, development in black and white races, xv, 50;
emotion effects, xi, 135;
functions and disorders, x, 342-6;
functions and structure, ix, 271-4;
functional capacity tests, x, 377-9;
position in circulatory system, ix, 51 (diagram), 197, 198, 199;

Simon's removal of, x, 131;
sugar handling by, ix, 291-2

Kilauea, volcano, iii, 103, 104, 105, 106-7, xiv, 322, 323

Kilimanjaro, Mount, xiv, 317
Killdeer (plover), xii, 262
Kilogram, iv, 46, viii, 28;
standard, iv, 69
Kilowatt, iv, 80, 312, vi, 85, vii, 370
Kilowatt-Hour, iv, 81, vi, 82, 84;
meters and charges for, vii, 174
Kinaesthetic Sensation, xi, 124-8;
space perception by, 166-7, 169-70, 175, 183, 186;
strain in attention, 228, 231-2;
in will, 265
Kindling Temperature, viii, 54
Kinematic, defined, iv, 382
Kinetic, defined, iv, 382
Kinetic Energy, iv, 79, 81, 83;
defined, v, 84, vii, 368;
forms of, iv, 82-5, 87-8
Kinetic System of Body, xi, 57, 60-1;
action in attention, 231-2;
connection with sensation, 67, 68, 127
Kinetic Theory, iv, 30, 131;
of gases, viii, 305-6, 378
Kinetics, defined, iv, 25
Kinetoscope, iv, 348, v, 330
King, Prof. L. V., i, 190-1
Kingfishers, xii, 267
King's River Canyon, iii, 43, 225
Kingston Earthquake, xiv, 340
Kiosks, weather, i, 75, 267, 376
Kipling, airship prediction, i, 43;
"female of the species," x, 162;
on dew ponds, i, 353
Kirchhoff, spectrum lines, ii, 17, 112-13
Kitasato, x, 164
Kitchens, lighting, vi, 276, vii, 71
Kite Balloons, v, 226
Kites, v, 230, 233-5;
action of wind on, iv, 42-3, 76 (fig.);
aerological uses, i, 18, 19, 22, 89

Kittatinny Ridge, Delaware Water Gap through, xiv, 169;
rock weathering at, 776
Kiwis, xii, 243, 249
Klamath Mountains, iii, 214
Klebs, Edwin, x, 141, 155
Knee-cap, ix, 69, 70 (fig.)
Knee Jerk, ix, 136
Knitted Goods, threads in, v, 277

Knitting machines, inventions, v, 282-3, 377, 378, 379

Knots, tying, by machine, v, 247-8
Knotweeds, xiii, 194
Knowledge, Bacon on, xi, 10;
Bergson on intuitive, xvi, 196;
Greek theories, 87-8;
growing thirst for, vi, 330;
relativity of, xvi, 195-6;
St. Augustine on proper, 99-100;
science and, 39-40, 41-2;
scientific, remarks on, iv, 26;
transmission means, xv, 142, 145-6, 167

Koch, Robert, x, 149-50, 169, 292, xvi, 184, 185;

"postulates" of, x, 150, 160, 196
Kodak, invention, v, 382
Koenig, acoustician, iv, 52, 233
Kohl-rabi, xiii, 223, 333-4
Kopjes, of S. Africa, xiv, 82
Korea, geology of, xiv, 125
Kraft Paper, v, 294
Krakatoa Eruption, xiv, 324-5;
atmospheric waves from, i, 188, xiv, 324;
distances heard, i, 188;
dust from, 57-8, iii, 100-1, xiii, 344, xiv, 325;
noctilucent clouds from, i, 18;
plant and animal extinction by, xiii, 345, xiv, 278

Krakatoa Island, xiv, 324;
restocked after eruption, xiii, 344-5, xiv, 278

Krasnoiarsk Iron, ii, 284
Kril, xii, 19
Krypton, in atmosphere, i, 11, 12;
symbol and atomic weight, viii, 383
Kut-el-Amara, i, 308

Labor-saving Machinery, remarks on, vii, 73-4, 75, xi, 268

Labrador, auks of, xii, 265;
climate of, xiv, 345
Labrador Current, i, 345, xiv, 305
Labradorite, iii, 329
Laccoliths, xiv, 109
Lace Coralline, xii, 47
Lace Leaf Yam, xiii, 89-90, 32 (illus.)
Laces, machine-made, v, 287-8
Lactic Acid, viii, 222, 223, 248, xi, 24-5;
fatigue product, 271-2;
stimulant, 272-3;
from fermentation, x, 138;
in body, 280
Lactometer, iv, 113
Ladakhis, character of, xiv, 245
Ladybirds, xii, 122;
lemon tree scales and, xv, 22
Laënnec, René, T. H., x, 108-10
Lag, angle of, vii, 362;
in electric currents, vi, 167;
correction, 262
Lagrange, mathematical work, xvi, 105, 125;
scientific work of, ii, 15, 71-2, 73, 74, 75, 216, 375

Laid Paper, v, 296
Lake, Simon, submarine of, v, 382
Lake Dwellers, agriculture, xiii, 210;
houses and implements, v, 14
Lakes, iii, 142-57, xiv, 198-212;
color of, viii, 40;
economic importance, xiv, 212;
ephemeral character, iii, 142, xiv, 198-9, 209-12;
few in mature regions, xiv, 160;
freezing of, iv, 150;
processes of destruction, iii, 157, xiv, 198, 210-12;
salt, 206-9;
shore-line development, iii, 57-8;
sizes and depths, xiv, 204

Lake Superior Region, glacial topography of, xiv, 56;
mines, iii, 356-7, 358, 361, viii, 163;
rock formation, iii, 172, 175, 176-7
Lakeview Gusher, iii, 354
Lamarck, cloud classification, i, 97;
on inheritance of acquired characters, ix, 325-6;
paleontological work, xvi, 169
Laminated Construction, vi, 316, vii, 371
Laminated Magnets, vi, 34
Lammergeiers, xii, 261
Lampblack, viii, 47
Lampreys, xii, 130-1
Lamps, portable, vi, 276-7, vii, 68-9
Lamp-Shells, xii, 47-8
Lancashire Cotton Mills, xiii, 236
Lancelets, xii, 129
Lancisi, x, 98, 154

Land, Land Surfaces, always some unsubmerged, xiv, 19-20;
area and distribution, 20-2;
area measurements, 10-11;
changes in features of, 28-30;
character of old and new, iii, 33-5, xiv, 48-9, 155-63;
elevation distribution, 26-7;
forms determined by earth movements and erosion, xiv, 33-79;
forms determined by rocks, 80-113;
heating and cooling of, i, 208, xiv, 346;
level changes (see Level Changes);
oldest, iii, 168-9;
relief features, orders of magnitude, xiv, 27;
rock formation, 19;
wind variations on, 351
(see also Continents)
Land-and-Sea Breezes, i, 131, 376

Land Animals, beginnings of, iii, 20, ix, 176;
development of, iii, 285-6, xii, 167;
salt in body fluid of, ix, 175-6
Land Filling, by machine, v, 258-9
Landlocked Areas, of continents, xiv, 190
Land Plants, beginnings, iii, 252;
development, xiii, 304-22
Land Plaster, iii, 376
Landscape Gardening, xiii, 267-97;
color contrast and induction in, xi, 95
Landscape Painting, xv, 302
Landscapes, changes in, iii, 10, xiv, 28;
dramatic interest in, xiii, 11
Land-sculpture, xiv, 30
Lane's Law, ii, 309, 371, 380, 383
Lanfranchi of Milan, x, 38, 39
Langenbeck, Bernard von, x, 130-1

Langley, Prof. S. P., aeronautical work, iv, 43-4, v, 231, 382;
astronomical work, ii, 144, 169, 213, 223-4;
measurement of heat of moonbeams, iv, 301;
on the camera, ii, 221;
spectrobolometer, 128, 186
Language, xv, 141-2;
association principle in, ix, 151-2;
clearness of, xi, 379;
importance of, ix, 152-3, xv, 68, 142, 143, 145-6;
inadequacy in feelings, 143;
making of, xv, 140-63;
psychological importance, xi, 200, 224, 225;
race and, xv, 159;
thought and, 143-5, 146
Languages, Aryan and Semitic, xv, 161-3;
changes in, 154-6;
difficulty of learning new, xi, 201;
foreign, advantages of learning, xv, 146;
foreign, sound of, xi, 103;
relationships and common origin, xv, 159-63
Lantern Gears, v, 27-8
Lanterns, enlarging and projecting, iv, 341-2

Lanthanum, symbol and atomic weight, viii, 383

Lap, cotton, v, 272;
wood pulp, 293
Lapilli, volcanic, xiv, 323-4
Laplace, asteroid hypothesis, ii, 258;
mathematical work, xvi, 105, 125;
nebular hypothesis, ii, 369-72, 374-5, 378, 380 (see Nebular Hypothesis);
on sound velocity, iv, 198-9;
other work, ii, 15, 72, 73, 74, 87

La Plata River, connections of tributaries, xiv, 187;
fish of, xii, 160
Lapwings, xii, 262, 263
Lard, animal fat, viii, 246;
calories in, ix, 299;
vitamins absent in, x, 261, 262
Larks, xii, 268
Larmor, light theory, xvi, 137-8;
magnetism theory, 193
Larrey, Jean, x, 130
Larvæ, affected by light, x, 253;
used in nest repairing, v, 10;
"rains," i, 356-7
Larynx, aphonia of, x, 29-30;
infection center, 220
La Salle, xiv, 192
La Soufriere, eruption of, xiv, 28, 338
Lassen Peak, iii, 103, 226, 176 (Pl. 10);
activity of, xiv, 315

Latent Heat, iv, 152-3, v, 169, 353-4, viii, 37-8, 378;
of fusion, iv, 152, 160, 161, 162;
of vaporization, 173-4, 187
Latent Period, of pain, xi, 121;
of sound, 105;
of touch, 111
Lateral Line, of fishes, xii, 137
Lateral Moraines, lakes formed by, xiv, 202

Lathes, development of, v, 42-6, 47, 52-3, 376, 378, 380, 383

Latin, in animal classification, xii, 29;
in cloud classification, i, 98;
in plant classification, xiii, 169;
languages derived from, xv, 160, 162

Latitude, barometric corrections for, iv, 122-3;
color of skin and, xv, 36-7;
of ships, how determined, v, 65;
plant distribution determined by, xiv, 364-6;
temperature and, 344-5;
weight of bodies, affected by, iv, 101-2
Laudanum, discovery of uses, xvi, 109;
first prepared by Paracelsus, x, 50
Laughing Gas, viii, 71, x, 123-4;
critical temperature and pressure, iv, 172
Laughter, emotional control of, ix, 164;
in infants, 349;
kinetic theory, xi, 355-7;
psychology of, 350-7
Laurel Family, xiii, 196-7
Laurel-leaf Points, xv, 109
Laurel Magnolia, xiii, 318 (fig.)
Laurent, chemist, xvi, 162, 163
Laurentian Highlands, antiquity of, xiv, 235
Laurentide Glacier, iii, 238
Lava, iii, 380, xiv, 17-18;
fissure flows, iii, 105-6;
forms of fragments, xiv, 323-4;
heat of molten, iii, 106-7;
heat retention by, xv, 230;
in Hawaiian craters, iii, 103, 104, 105, xiv, 322-3;
porous, iii, 101 (see Pumice);
rate of flow, 104-5;
sheets, 102 (fig.);
soils from, 28, xiv, 329;
spine of Mount Pelee, iii, 103
Lava-dam Lakes, iii, 156

Lava Formations, xiv, 102-4, 164, 170, 172, 188;
erosion effects, 103-5;
extent of, iii, 106;
in Appalachian trough, 212;
in British Isles, 191;
in Colorado, 177;
in Columbian Plateau, 105-6, 227, 228, xiv, 102-3, 104, 164, 170, 172, 188;
in Deccan of India, 105-6, 228, xiv, 103;
in East Africa, 103;
in Keewatin Series, iii, 169;
in Lake Superior region, 177;
in Snake River Valley, 228
Lava Rocks, not crystallized, iii, 170-1
Lavender, source, xiii, 205
Laveran, Alphonse, x, 155

Lavoisier, chemical work, xvi, 120, 121, 159-60, 177;
combustion theory, viii, 34
Law, beginning of, xv, 360-3, 367-74, 379-80
Lawn Sprinklers, revolving, v, 143
Laxatives, use of, ix, 252
Lazear, Dr. Jesse W., x, 160, 162
Lead, affinity intensity, viii, 128;
alloys with tin, melting point, iv, 161-2;
atomic weight, viii, 189, 383;
commercial source, iii, 330;
compounds, viii, 29, 162;
density of, iv, 113;
extraction from ores, viii, 270, 271;
from radium disintegration, 185;
fusibility, 384;
melting point and requirements, iv, 162;
occurrence of, viii, 129;
opaque to X-rays, vii, 250, 251;
ores of, viii, 154, 198, 199-200;
positiveness, vi, 59;
production, iii, 362-3;
properties, viii, 126-7, 154, 162;
refining of, 272;
refining, electrolytic, vii, 320;
specific gravity, viii, 384;
symbol, 383;
test for, 287, 288;
uses, iii, 362, viii, 162

Lead (of electric currents), vi, 171-4, 261, 262;
angle of, vii, 362

Lead Arsenate, viii, 169

Lead Cells, vi, 130, 146-7, 150-1, viii, 167-9

Leaders, of crowds, xi, 332-3;
of primitive peoples, xv, 363-6
Lead Pencils, graphite of, viii, 43

Lead Peroxide, in storage batteries, viii, 167-9

Lead Pipes, corrosion of, viii, 162
Leadville Mining District, iii, 363, 364
Leaf Mosaic, xiii, 38
Leafstalks, xiii, 34, 35 (fig.);
light effect on, 87-8
Leakage, electrical, vii, 10-11, 371
Leaning Tower of Pisa, ii, 53, iv, 100-1;
Galileo's use of, iv, 28, 97
Learning, Egyptian advice, xvi, 70;
experience and, viii, 269
Learning Processes, xi, 33-46, 68;
rules, 211-15
Leather, making of, viii, 257
Leather Collar, Maudsley's, v, 99
Leaves, xiii, 32-43;
absent in some plants, 15, 28, 30, 31, 99, 100;
arrangement on stems, 38;
branches as, 378, 379;
buds of, 34;
colors, 42;
coloring in autumn, 79;
coloring in tropics, 361;
compound, 36-7;
first, 60-1;
forms and varieties, 34-6;
fossils of, 302;
functions, 37-8, 42, 61, 77-84;
hairy covering, 104-5, 379;
insect-capturing, 39-41;
light and, 38-9, 87-90;
large, examples, 189, 217, 359;
moving, 105-6, 113, 114;
none in fungous plants, 70;
not decisive in family grouping, 184;
of desert plants, 41-2, 106-7, 378, 379-80, xiv, 378-9;
of evergreens and deciduous trees, xiii, 174, 175;
of ferns, 63, 65;
of monocotyledons and dicotyledons, 176, 178;
osmotic pressure, 94;
reproduction by division of, 165-6;
rigidity of, viii, 338;
shedding of, in dry periods, xiv, 369;
skeleton (Madagascar yam), xiii, 90;
sleeping, 88-9, 113;
stems acting as, 28-31, 378;
structure, 78-9;
struggle for sunlight, 38-9, 87-90;
tendrils on, 38;
transitional form, 43;
transpiration, 103, 104, 113, 374, 378, 379;
uses, summarized, 42-3;
veins, 32-3;
water-dripping, 107-8;
water-storing, 41-2, 106-7, 379-80;
water-supply methods, 102-9;
wilting, 102, 103, 114
Leblanc Process, viii, 276-7
Leclanche Cell, vi, 138
Lee, Dr. Willis T., i, 47
Lee, William, knitting machine of, v, 283
Leeches, xii, 51, 55-6
Leeuwenhoek, Antonius von, xvi, 107-8, 112
Legs, bones of, ix, 68-9, 70 (fig.);
bones, growth, 56, 58;
equal length, 169-70;
evolution of, xii, 167;
in insects, 102;
length of men and apes, xv, 57, 59;
muscles of, ix, 76;
nerves of, 124-5;
vestiges of, in snakes, xii, 213
Legumes, xiii, 56;
nitrogen fixation by, viii, 74, 346, xiv, 66
Lehigh River, gap of, xiv, 51, 167

Leibnitz, mathematical work of, ii, 14, xvi, 105;
monad theory, 117-18;
scientific work, 113
Leif Ericson, xiv, 261
Lelande Cell, vi, 137, 139
Lemmings, xii, 290, 291
Lemon Oil, viii, 240, 252
Lemon Tree, origin, xiii, 225;
scale on, xv, 22;
spread, xiii, 354
"Lemuria", xii, 192
Lemurs, xii, 374-6;
primates, 373;
feet of, iii, 301 (fig.)
Length, British units, iv, 45, 69, 283;
measurements and standards, xvi, 130;
metric units, iv, 46, 69, viii, 28
Lenoir Motor Car, v, 213
Lenses, iv, 337-8;
achromatic, iv, 372-3, xvi, 125-6;
Bacon's improvements, 101;
for eye defects, ix, 111, 112, 113, 114;
formation of images by, iv, 337-42, ix, 108-9;
of eye, 109-11, 113 (fig.);
refraction of light by, ii, 99
Lenticels, xiii, 26
Lenticular Clouds, i, 104, 376
Lentils, xiii, 198, 223
Lenz's Law, vi, 311, vii, 371

Leonardo da Vinci, anatomical work of, x, 51-2;
astronomical work, ii, 41;
idea of moving bodies, 63;
views of fossils, iii, 14
Leonids, ii, 288
Leopards, xii, 357;
deer-hunting with, xv, 223
Lepidoptera, xii, 115-20;
"blood rains" of, i, 358
Lepidosirens, xii, 142, 166

Leprosy, immunity and susceptibility to, xv, 50, 51

Lesions, meaning, x, 98, 322;
X-ray treatment, vii, 253, 255-6
Lettuce, as food, ix, 27, 30;
family, xiii, 206;
origin, 223;
wild, 105
Leucippus, theory of matter, xvi, 83, 84, 118
Leukaemia, metabolism in, x, 272
Leucocytes, germ destruction by, x, 209-10
Levees, effects of, xiv, 162
Level Changes, iii, 76-83, xiv, 33-6;
due to earthquakes, iii, 97, 98;
due to lateral pressure, 85;
effect on erosion cycles, 36-7, xiv, 40, 163-4;
shown by erosion of rocks, iii, 171-2

(see also Elevation, Rejuvenation, Subsidence)

LeVerrier, astronomical work of, ii, 16, 79, 189, 269;
meteorological work, i, 217, 228
Levers, v, 21-5;
Archimedes on power of, iv, 25;
classes of, remarks on, 89;
clubs as, v, 12;
friction in, iv, 93;
legs as, v, 215;
liquid, 97-103;
mechanical gain in, iv, 41;
primitive beginnings of, 24, v, 9, 14-15;
principles shown by Archimedes, xvi, 89;
revolving, v, 25-35
"Leviathan," steamship, v, 193-4
Leviathan Reflector, ii, 16-17, 105-6
Levulose, viii, 226, 248
Lewis & Clarke reports, xvi, 171
Lewis Machine Gun, v, 365-6
Lex Talionis, xv, 371

Leyden Jar, iv, 267, 368 (fig.), vii, 259, 260;
discovery and experiments, xvi, 188-9;
oscillations of, iv, 313
Lianes, xiii, 362, 363, 366
Liberty Engines, v, 53-4
Libyan Cat, xii, 355
Libyan Desert, rain in, i, 210
Lichens, species, xiii, 323
Lick Observatory, ii, 142-4, 148
Licorice Plant, leaves, xiii, 113
Liebig, Justus von, x, 126;
chemical work, xvi, 162;
on fermentation, x, 138-9
Liège, siege of, xiv, 92
Life, antiquity on earth, xiii, 314;
beginnings on earth, iii, 20, 173, 249, xv, 71;

Bergson on, xvi, 196;
brain in relation to, xi, 15;
Brunonian (excitability) theory of, x, 89;
cell basis of, ix, 17, x, 119, xii, 10, 14, xv, 16, 381;
chemical nature of processes, viii, 353, 355;
chemical theories of, x, 69, 84;
colloidal theory, xii, 11-13;
conditions necessary, ii, 242-5;
conscious, parts concerned in, ix, 21-2;
demand for, in nature, xiii, 69;
dependence of, on sugar products, ix, 27;
distinctions from inorganic realm, xii, 13-14;
fundamental instincts, xi, 49-56;
Hoffman's "ether" theory, x, 85;
instinct for renewal, xiii, 116, 167;
instinct of preservation of, x, 9-10, 282-3;
interest and triteness, vi, 330;
irritability theory of, x, 86, 87, 89;
James on complexity of, 244;
low temperature effects, i, 32;
maintenance of, ix, 18-23;
mechanical explanations of, x, 70, 71, 72;
metals congenial to, viii, 148;
nature of processes, ix, 34;
necessity of water, xi, 66;
only thing man cannot produce, vii, 310;
origin, ii, 243, 245, xii, 9-13, xiii, 300-1;
Paracelsus on process of, x, 49;
possibility in other worlds, ii, 242-53;
possibility on Mars, 228-32, 237-8;
protoplasm the seat of, viii, 356, ix, 13, 17, x, 228, xiii, 74;
recent lengthening in U. S., x, 291;
salts in relation to, ix, 174-5;
savage attitude toward, xv, 327;
seat of, in body, ix, 11-12, 17;
sea water favorable to, viii, 355;
signs (proofs) of, ix, 9-17;
soul as source of (Stahl), x, 84;
spontaneous generation of, 139;
temperature in relation to, ii, 249, v, 348, x, 250-1;
universality, Indian belief, xvi, 44
(see also Vital Processes)
Life Plant, xiii, 165
Lift, of aeroplanes, i, 288, 298
Lifting Magnets, iv, 289, vi, 86, 94
Lifting Pump, iv, 126
Lift Locks, of canals, v, 103
Ligaments, ix, 70-1

Ligatures, history of use of, x, 14, 27, 55-6, 91, 121-2, 123, 129-30, 146, 148

Light, iv, 322-34;
aberration of (see Aberration of Light);
absorption in space, ii, 160, 354-5;
absorption of, by objects, iv, 364;
actinic effects, vii, 250;
artificial, applications of, iv, 50-1;
artificial, colors, of, ix, 115;
bacteria destroyed by, viii, 332;
body regulation to, x, 250;
chemical action of, viii, 171-2;
chromatic aberration, ii, 99-100;
corpuscular theory of, iv, 47, 50, xvi, 136;
decomposition, ii, 99, 111, 112, iv, 357-9
(see also Spectrum, Spectroscope);
deflection of, 330, 374;
deflection by sun, ii, 81-2;
diffraction, i, 183, iv, 326;
effects of objects on, 323-4;
effects on organisms and man, x, 253-4;
Einstein theory, ii, 80-2;
electrical production, inefficiency, vi, 268;
electromagnetic theory of, iv, 54, vi, 25, vii, 371, xvi, 137-8;
eye and, vi, 270-2, xi, 86, 95-6;
eye regulation to, x, 254;
from sun, importance of, ix, 25-6;
"gentleman" of physics, iv, 50;
glowing effects on minerals, vii, 254;
injury from excessive, 153;
intensity unit, iv, 351-2;
interference of, 376-8;
instinct of seeking, xi, 52-3;
invisibility, iv, 333-4;
machines responding to, v, 331-2, 332-3;
measurement of illumination of, iv, 350-2;
measurement of intensity, viii, 374;
monochromatic, iv, 364, 365;
of electric lamps, vi, 268;
of firefly, 268;
of glowworms, xvi, 144;
of moon, ii, 200;
of stars, 296;
of sun, 168-9;
penetration of ocean by, xii, 22;
perception limits, iv, 360-1;
perception of, in animals, ix, 105;
physiological sensation, vii, 249;
polarization, iii, 319-20, iv, 353-6;
polarization, discovery, xvi, 119;
production by various kinds of rays, iv, 378-80;
quantity unit, 352;
radiant energy, 322, ix, 114;
rays of, iv, 323;
reflection and refraction (see Reflection and Refraction);
seeing by, iv, 322-3, 324-9;
shadows cast by, 332-3;
theory of, present state, 50;
transformed to musical sounds, v, 332-5;
transmitted by ether, vi, 119, 120, 269, vii, 259;
traveling of, in straight lines, iv, 330;
velocity, 323;
velocity constancy, xvi, 196;
velocity in different media, iv, 327;
velocity, methods of obtaining, ii, 59-60, 91, 167;
vibrations and colors of, ix, 115;
wave theory, iv, 47, 353, vi, 118-19, 269, xvi, 136-8;
wave theory discovery, 119;
white (see White Light);
wind effects on, iv, 211
(see also Light Waves, Sunlight)
Light-headedness, production of, ix, 266-7
Lighthouses, strength of, xiv, 300-1

Lighting, art of, modern advances in, iv, 50-1;
direct, xi, 277, 373;
emotional effects, vi, 273;
factory, xi, 361;
flood, vi, 283;
modern gas, viii, 60;
proper and improper, vi, 273-5;
unit of intensity, vii, 368

(see also Electric Lighting, Lighting Systems)

Lighting Systems, color effects, iv, 370;
exterior, vi, 278-83, vii, 339-43;
interior, vi, 275-8, vii, 68-72
Lightning, i, 146-57, vii, 201-19;
annual deaths by, x, 254;
awe-inspiring power, vii, 201, 202;
causes, i, 149-52, iv, 269, vii, 206-15, 217-8;
current strength, i, 152-3;
danger and protection, 155-7, vii, 201-2, 218-19;
danger in aeronautics, i, 303;
defined, 376, vii, 371;
displays, 203;
distance, how determined, i, 187, vii, 210;
electromagnetic waves from, 260;
fire from, xv, 320;

Franklin's experiment, i, 141, vi, 10-11, 14-16, vii, 204-5;
large raindrops and, 215-17;
multiple flashes, i, 146-8;
nitrogen fixation by, 13, 34-5;
oscillations, vii, 208, 366, 374;
ozone produced, i, 15;
photographic study, 146-8, 151;
protection of electric lines, vii, 16-19, 49-50;
thunder from, i, 192-3, vii, 210-11;
types, i, 146, 148-9, vii, 205-6, 211-15;
visibility, i, 152;
voltage, 151-2, vii, 206-7;
weathering agency, iii, 24;
wind effects, i, 148

Lightning Arresters, vii, 17-18, 49-50, 362, 371

Lightning Prints, i, 154-5, 376

Lightning Rods, i, 156-7, 376, iv, 270, vii, 218-219, 371;
invention, i, 141, vi, 14, 16;
principle, vii, 209;
use of points, vi, 297
Light-Pillars, i, 376
Light Waves, iv, 353, vi, 118-19, 269;
atmospheric effects, i, 165-6, 170-1;
caused by molecular vibrations, iv, 360, 363, 379;

Doppler's principle, ii, 119, iv, 210;
glass and, 183;
interference of, 376-8;
length and frequency, vii, 250, 260;
length and frequency with different colors, iv, 359, 360, 365, ix, 114, 115;
motion of, xvi, 137;
unit of length, iv, 359, xvi, 130
Light-Year, ii, 315, xvi, 33

Lignite, iii, 344, 345, 346, 347, 348, viii, 44, 45

Lilac, fertilization, xiii, 143-4;
leaves, 38
Lilienthal, Otto, v, 231
Lily, African, xiii, 38;
leaves, 38, 176
Lily Family, xiii, 183-4
Lily of the Valley, xiii, 45, 47, 178
Lima Beans, variation in, xiii, 331
Limacina, xii, 19
Lime, calcium oxide, viii, 149;
in earth's crust, iii, 308;
in water, viii, 40, xiv, 142, 147;
production, iii, 373, viii, 150, 276;
slaking of, 38-9;
uses, iii, 373, viii, 149-50, 278, 323, 347
Limes (fruit), origin, xiii, 225;
spread, 354

Lime Salts, body needs of, ix, 32, 33, 33-4, 174;
in bone, 57;
in diet, x, 256
Limestone, iii, 13, 380;
cliffs of, jointing in, xiv, 133;
composed of carbonate of lime, iii, 25, 308;
destruction by frost, xiv, 76-7;
formation of, viii, 152;
lime making from, 149, 150, 276;
marble from, iii, 169, 189, 371;
occurrence in U. S., 371-2;
polyzoans in, xii, 47;
residual soils from, xiv, 68, 145;
sedimentary rock, 18;
solubility, iii, 24-5, 126, viii, 151, xiv, 145-6, 147;
travertine deposits, 146;
uses, iii, 325-6, 373-4, v, 315, 318, viii, 151, 280;
weathering of, iii, 27
Limestone Formations, iii, 185, 267, 270;
caves in, 127, viii, 151, xiv, 147-8;
underground streams in, iii, 116, xiv, 149-50
Limonite, iii, 333, 359, viii, 130, 156
Lincoln, assassination incident, xi, 323;
in Holmes's "goodly company," x, 134
Linden Trees, xiii, 324-5, 345-6
Linen, antiquity of, xv, 243;
as clothing material, ix, 311-12, x, 307, 309;
cellulose composition, viii, 254;
from flax plant, xiii, 235;
paper from, v, 290-1, 292

Lines of Force (electric), iv, 261-2, vi, 295-6

Lines of Force (magnetic), iv, 251-2, 261, 274-5, vi, 33, 54, vii, 371;
cutting of, iv, 301-8, vi, 23, 54, 307-8;
direction, iv, 277-8, vi, 54-5, 88-90;
leakage, vii, 371;
least resistance tendency, vi, 43-4, 96;
shortest direction tendency, 219;
terrestrial, 39, 40;
terrestrial, in relation to aurora, i, 159-60
Line Squalls, i, 138-9, 376
Link Motion, v, 208-10, 379
Linnæus (Carl von Linné), x, 84, 134;
natural history work, xvi, 116, 126, 139, 165;
rattlesnake named by, xii, 235
Linotype, Mergenthaler, v, 308-10, 381-2
Linsangs, xii, 353
Linseed Oil, viii, 231-2, 246;
action in paint, 264, 265;
source, xiii, 235;
spontaneous combustion of, viii, 55-6
Lions, xii, 359-60;
fearlessness, xi, 136;
instinctive fear of fire, 46;
strength of, xv, 16, 18
Lipari Islands, volcanoes of, xiv, 317
Lipases, viii, 357, x, 326
Lipins, viii, 350-1

Liquefaction of Gases, i, 29, 32, iv, 143, 153, 171, 188, 191-2, viii, 303-4

Liquid Air, i, 26, 29-33, iv, 190-2, vii, 323, viii, 68;
boiling point, iv, 173;
oxygen production from, viii, 67, 274;
temperature, and pressure, iv, 172
Liquids, boiling of, iv, 167-74;
boiling point and chemical composition, viii, 298-301;
boiling point and pressure, iv, 168, 169-72, v, 354, viii, 303-5;
buoyant powers of, iv, 30, 103-7;
chemical aspects, viii, 22, 297-301;
compressibility, v, 107;
conversion to gases, iv, 152-3, 153, 167;
critical temperature, 171-2, viii, 303-4;
density, how measured, iv, 113, vi, 147;
distinguished by pressure and diffusibility, iv, 22-3;
elasticity of, 156, 158;
evaporation, 167, 174;
expansion by heat, 135, 138;
expansion coefficient, 145;
fractional distillation of, 168;
heat effects on, 144, viii, 25;
heat transmission in, iv, 138-9, 177-8;
intermingling of, in contact, 131;
latent heat (see Latent Heat);
molecules in, iii, 309, iv, 22, 131, 152, 167, 363, viii, 23, 24;
osmosis, xiii, 90-1;
pressure of, iv, 116-19;
solubility in water, viii, 111-12;
sound velocity in, iv, 198;
specific gravity, how determined, 112, 113;
spectra of incandescent, ii, 112, iv, 360, 363;
supercooled and heated, viii, 113, 304-5;
vapor pressure of, 303-5;
vaporization of, iv, 173-4;
vibrations of, 196, 215;
volatile, 174
Lister, Joseph, x, 144-6, xvi, 182-3;
importance of work of, x, 40, 107, 149, 381;
on Pasteur, 143
Liter, standard of volume, viii, 28
Lithium, viii, 128, 132, 133;
atomic weight and symbol, 383;
flame color, 301;
specific gravity, 384;
spectrum of, 301-2;
test for, 287, 289
Litmus, viii, 114
Little Falls Gorge, iii, 243
Little Red Riding-hood, xv, 358
Littoral Fauna, xii, 16, 17
Live Oaks, xiv, 370
Liver, bile secreted by, ix, 237, 275;
changes caused by shock, xi, 59;
development in black and white races, xv, 49-50;
disorders of, x, 330;
emotion effects on, xi, 136-7, 138;
failure in diabetes, ix, 293;
functions, x, 329-30, 347, xi, 60;
gall stones in, ix, 286;
glycogen storage in, 291, 292, 293, 298;
hemoglobin decomposed in, 184, 275;
in circulatory system, 196 (fig.), 198, 245;
inflammation of, x, 224;
secretin effects on, 325;
therapy of, 382-3;
urea production in, ix, 284, 285;
waste removal by, 271, 275
Liverwort, reproduction, xiii, 166, 167

Livingstone, David, African exploration, xiv, 196;
quoted, 78
Lizards, xii, 182, 203-10;
descent of, 203;
embryo of, xv, 54;
Mesozoic, iii, 295
Llamas, xii, 313, 315 (fig.)
Lloyd's, insurance of, i, 270
Load Factor, vi, 380-2
Loadstones, vi, 28-9, vii, 372;
at magnetic pole, vi, 30;
Gilbert's studies, 11, 12;
used as suspended compass, 29, 31 (fig.);
(see also Lodestone)
Lobsters, iii, 260, 278-9, xii, 87
Locaille, xvi, astronomer, 124
Locke, John, medical work of, x, 74-5;
philosophy of, xvi, 111, 115, 117
Lockjaw, x, 298-9;
immunity to, 206, 207;
prevention of, 218

Lockyer, Sir Norman, discovery of sun prominences, ii, 181;
collision theory, 327, 333;
star classification, 309-10;
on temple orientation, 26
Locomotion, forms of, ix, 82, 155-6;
friction necessary to, iv, 94;
of animals, means of, ix, 73-4;
of serpents, xii, 212;
reflex processes in, ix, 156-9;
rolling, v, 215
Locomotives, Steam, v, 207-12, 377, 378-9;
boilers, 140 (see Boilers);
efficiency, 155;
compared with electric, vii, 193-4;
power source of, ix, 15;
smoke from, i, 64, vii, 345;
sound of passing, iv, 210
Locomotor Ataxia, ix, 90-1
Locusts, xii, 108-9;
jaws of, 100;
seventeen-year, 112, 113;
as food, xv, 134
Locust Trees, in landscaping, xiii, 271-2;
in Long Island, 354;
in pea family, 198;
lightning danger, i, 155;
petals, 47;
sleeping of leaves, 89, 113
Lodestone, iv, 52-3, 242, viii, 156;
name of, iv, 243,
(see also Loadstone)

Lodge, Sir Oliver, Evesham experiments, vii, 352;
on atmospheric electricity, 212;
on electrons, vi, 114;
on forces in atoms, 115;
on luminiferous æther, 118;
wireless system, xvi, 191
Lodgepole Pines, xiv, 374
Loess, i, 53-4, iii, 73-4, 380, xiv, 63, 72-5
Loire River, base-leveled stream, xiv, 49
London, "Black Day," ii, 211;
eclipses in, 214;
fogs, i, 94;
harbor of, xiv, 270;
sewage disposal, viii, 327;
smoke deposits, i, 65;
tea market of world, xiii, 231;
water purification, viii, 319-20
London-Paris Air Route, i, 44-5, 95, 285-6
Long, Crawford W., x, 124, 125

Long Branch, N. J., wave destruction at, xiv, 45, 302

Long Distance Electrical Transmission, alternating and direct currents in, vi, 159-61, 195-6;
choke coils in, vii, 50;
condensers in, vi, 285-6;
difficulties, 367;
high voltages best, 159, 161, 163, 331-2;
high voltages and leakage, vii, 10-11;
of Niagara Power Plant, vi, 376-8;
power-factor correction, 262;
present distances attained, 365;
progress in, vii, 9-10;
synchronous condensers in, vi, 262;
three phase alternators in, 206;
transformers, 309, 324;
transcontinental, 10, 367-8;
vacuum tubes in, 125

Long Distance Telephony, inductance reduction, vii, 104-5;
method of connecting cities, 104;
phantom circuit, 105-6, 119;
repeating stations, 114;
in United States, 91-2
Longfellow, stanzas on nature, xvi, 43
Long Heads, physical characteristics, xv, 47;
racial divisions, xvi, 48-9;
skull index in, xv, 42
Long Island, bowlders on, xiv, 69;
locust tree on, xiii, 354;
opossums in, xii, 275;
outwash plain on, iii, 69;
plant conditions, xiii, 382;
scallop fisheries, xii, 65;
terminal moraine on, iii, 68, 237, 238
Long Island Sound, false corals of, xii, 47;
oysters of, 61;
oyster "drills" of, 72
Longitudinal Rivers, xiv, 153-4
Looking-glass, images in, iv, 335-6
Looming, optical, i, 172, 174, 376

Looms, history and development, v, 268, 277-82, xv, 245-7;
various inventions, v, 376-7, 381, 383
Loons, xii, 250
Loop-the-loop Cars, iv, 74
Loosestrife, xiii, 140-1, 203
Lop-Nor Desert, xiv, 209
Lorentz, light theory, xvi, 137-8;
relativity theory, iv, 18, xvi, 196
Lories, Australian, xii, 266-7

Los Angeles, electric power supply, v, 81, vi, 363;
telephone connection with New York, 367-8
Loudness, of sound, iv, 211;
to what due, xi, 104
Louis XIV, high heels introduced by, x, 306;
observatory founded by, ii, 58;
on Pyrenees Mts., xiv, 239
Louis, Pierre C. A., x, 108
Louisiana cotton, xiii, 237;
salt deposits, viii, 140;
sulphur deposits, 76
Louisiana Purchase, xiv, 192, 193, 311
Louisville, early growth, xiv, 219;
water supply, viii, 318
Loup Fork, xiv, 161
Love, fundamental impulse, xv, 185;
motor character, xi, 58;
sentiment of, 149-50;
unknown to savages, xv, 279, 321
Lowbrows, xv, 43
Lowell, Percival, ii, 233-4, 237, 271;
reference to, xi, 218
Lowell Observatory, ii, 146-7, 148
Low German, xv, 162
Lowlands, xiv, 213
Lows, Low Pressure Areas, i, 135-6, 137, 376;
of Iceland, 361;
movement, 134-5, 237;
physiological effects, 330;
thunderstorms and, 138;
wind and weather attendants, 125, 218, 236, 237

(see also Pressure Areas)
Lubricants, fatty, viii, 247;
graphite, 43, vii, 308, 309;
oil-dag, 300
Luciferin, xii, 20
Lues, curability of, x, 134;
germ of, 195, 199;
immunity to, 207
Lumber, chief source of, xiv, 383;
from heartwood, xiii, 25
Lumen, light unit, iv, 352

Luminous Plants and Animals, i, 346-7, xii, 20, xiii, 203-4, xvi, 144, 146

Lunation, defined, ii, 196
Lundy, Lake, iii, 149
Lung Fish, iii, 283 (fig.), xii, 164-6
Lungs, ix, 254-6;
aeration of blood by, 253, x, 62, 63, 331;
carbon dioxide diffusion by, ix, 263-7;
circulation of blood through, 196 (fig.), 198-200;
congestion of, x, 341;
development in black and white races, xv, 50;
diseases of, susceptibility to, 50, 51;
dust in, ix, 223;
evolution in animal kingdom, xii, 164-5, 169, 187, 248;
external respiration by, x, 339;
functions in maintenance of life, ix, 21-3;
infection through, x, 198, 220;
in pneumonia, 289;
oxygen supply through, ix, 51 (diagram), 253, 258;
poisons exhaled by, 269;
water loss by, i, 317, ix, 274
Lupine, leaves, xiii, 113
Luray Caverns, iii, 127, xiv, 148
"Lusitania," loss of, xi, 332
Luster, of metals, viii, 126;
of minerals, 201
Lycopodium Selago, xiii, 305-6, 322
Lycopods, iii, 253-4, 256
Lye, making of, viii, 276, 278;
in soap-making, 221
Lyell, geological work, xvi, 126, 171
Lymphatics, ix, 222-5;
in circulatory system, 196 (fig.)
Lynx, xii, 364-5
Lyra, elliptic nebulæ in, ii, 360;
movement of sun toward, 18, 122, 137, 305-6
Lyric Poetry, primitive, xv, 319-21
Lysins, x, 211
Maas River, shifts in delta, xiv, 186
(see also Meuse)
Macaques, xii, 378-9
Macaws, xii, 266
McCormick, Cyrus, reaper, v, 244-7, 249, 379
MacCulloch, on rocks, xvi, 170
McDowell, Ephraim, x, 122, 147
Mace, spice, xiii, 261, 262
Mace, symbol of power, xv, 208

McGehee, Arkansas, antimalarial work in, x, 174

Machine Guns, v, 362-8, 380, 382

Machines, advantages of electrical drive, vii, 62;
air-cushioning in, v, 134;
"animated," 326-44;
contract with operators, vii, 121-2;
displacement of men by, v, 17-18;
early, iv, 26;
efficiency (see Efficiency of Machines), elementary, iv, 89-94, v, 20-41;
fascination of, vi, 175;
force and resistance law, iv, 90, 92;
for making machines, v, 42-56;
friction in, iv, 92-4;
history of development, v, 15-19, 376-84;
hydraulic, reliability, 106;
instruction of workers, xi, 363-5;
labor-saving, vii, 73;
mechanical advantage, iv, 89, 98;
parts named from human parts, v, 20;
skilled artisans and, 42, 46;
standardization of parts, 48-50, 53-4;
summary of progress in, 376-84
Machine Tools, development, v, 42-56, 376;
in relation to automobile industry, 55-6, 214, 383

Mackerel Sky, i, 100, 376
Mackerel Year, i, 359
Mackintosh Waterproof Cloth, xiii, 245
Madagascar, chameleons of, xii, 210;
crocodiles of, 199;
former union with Africa, 376;
fossane of, 353;
lemurs of, 374, 375;
laceleaf yam, xiii, 89-90;
orchid, 48;
ratite birds in, xii, 249;
separation from Africa, xiv, 273;
tenrecs of, xii, 367;
tortoises of, 191, 192
Madder Family, xiii, 205-6
Madeira, discovery of, xiv, 309;
oceanic volcano, 289, 316
Madrepores, xii, 39-40
Maeterlinck, on eelgrass, xiii, 150-1
Magazines, printing and binding, v, 305-7
Magdalenian Period, xv, 105, 109;
clay models of, 118-19
Magdeburg Hemispheres, iv, 29
Magellanic Clouds, ii, 355
Magendie, François, x, 126, 127, xvi, 186
Maggiore Lake, iii, 146
Magi, Persian, xvi, 59
Magic, history of, xvi, 44, 59
Magic Lantern, iv, 341-2
Magma, viii, 191
Magnesium, viii, 17, 127, 148-9, 153;
affinity intensity, 128;
atomic weight and symbol, 383;
automobile parts made of, 127, 149;
electrolytic production, vii, 320-1;
fusibility, viii, 384;
ignition, 53, 54;
in body, 354;
in body fluids, ix, 174;
in earth's crust, iii, 308, viii, 19, 129, 192, 195, 196;
light of, 60, 172;
plant needs of, 337, 341;
specific gravity, 384;
test for, 287, 289
Magnesium Chloride, in sea water, xiv, 295-6
Magnesium Compounds, viii, 130, 148-9;
deposits of, 138, 195, 196, 275;
in hard water, 40, 318, 322-4;
lightness of, 29
Magnesium Oxide, medicinal uses, viii, 153
Magnetic Axis, of earth, iv, 250
Magnetic Blowout, vii, 37, 39
Magnetic Circuits, vii, 364;
force of, vi, 93

Magnetic Disturbances, accompanying aurora, i, 161;
due to moon, ii, 201;
sun-spots and, 176, 186
Magnetic Equator, iv, 246
Magnetic Fields, iv, 251, vi, 31, vii, 368;
concentration of, vi, 91-2;
distortion, 43-4;
electromotive force created by, 50-3, 54;
electron theory, 128;
generator and motor actions in, 218-19;
of atoms, 117;
of earth, iv, 253, vi, 39, 40;
of electric currents, iv, 274-5, 277, 279 (fig.), vi, 19-20, 88-91;
of sun, ii, 177-9;
spectra of vapors in, 178;
strength or intensity, iv, 252, vii, 368, 370
Magnetic Force, vii, 369
Magnetic Leakage, vii, 371
Magnetic Meridians, iv, 246
Magnetic Needle, iv, 243-4;
dip or inclination of, 245-6;
earth's action on, 248;
electric current effects on, 273-4, 275-6, 278-9

Magnetic Permeability, vii, 372
Magnetic Poles, vii, 374;
force of attraction between, iv, 249

Magnetic Poles (of earth), iv, 246, 248, vi, 29-30;
aurora in relation to, i, 159-60
Magnetic Saturation, vii, 372
Magnetic Screens, vi, 32 (fig.)
Magnetic Storms, vi, 40
Magnetism, iv, 242-55, vi, 27-45;
daily application, xvi, 19, 30;
effects on body, vii, 246, 247;
electricity and, vi, 12, 19-20, 27-8, 86, iv, 256, 276;
electron theory, vii, 371;
energy in, iv, 82;
force of, how measured, 249;
history of, 52-5, vi, 9-26, xvi, 109, 122;
law of attraction and repulsion, vi, 18, 42-3, 286-7;
of direct and alternating currents, 155-6;
lines of force (see Lines of Force);
of earth, iv, 248-50, 252, vi, 29-30, 39-40;
of earth, connection with internal iron, xiv, 11;
of rotating bodies, ii, 178, vi, 21;
residual, vi, 191, vii, 372;
science of power, xvi, 36-7;
term as used, vii, 372;
universal presence, vi, 40

(see also Electromagnetism, Magnetic Fields, Magnets)

Magnetite, iii, 333-4, viii, 156;
ores in Adirondacks, iii, 359;
properties of, iv, 242
Magnetization, iv, 242;
aided by striking, 253;
by electric currents, 286-8, vi, 30, 50;
by induction, iv, 243, 253;
by lightning, i, 152-3;
by loadstone, vi, 29;
internal effects, 36-7;
of iron structures, iv, 253;
molecular effects, 245, 253;
processes of, vi, 44-5;
test, 43
Magneto Generators, vi, 215-16
Magnetomotive Force, vi, 92-3
Magnetos, automobile, vii, 140-41
Magnets, iv, 242-4;
action of, 250-1, vi, 31-2;
aging of, 45, vii, 159;
attraction and repulsion of, iv, 242, 244, 245, 249, vi, 33, 42-3, (fig.);
demagnetization methods, iv, 253, vii, 366;
effect on compass, vi, 27, 42-3;
electromotive force produced by, iv, 303;
force, how measured, 249-50;
heat and jarring effects, vi, 34-8, 117;
internal constitution, 36-7;
laminated, 34, 35 (fig.);
lines of force, 33
(see also Lines of Force);
lifting force of, iv, 289;
making of, vi, 44-5 (see Magnetization);
natural, iv, 242;
penetrability, 250, vi, 31-2;
permanent and temporary, iv, 243, vi, 30;
poles of, iv, 242, 244-5, 253, 262, vi, 31, 42, 43;
types, 30-1, vii, 372;
uses, commercial and industrial, iv, 255, viii, 270

(see also Electromagnets)
Magnifying Glass, iv, 343
Magnitude, illusions of, xi, 184-90

Magnitude of Stars, absolute (see Absolute Magnitude);
catalogued by Hipparchus, ii, 31;
classification by, 295-6, 297;
conditions affecting, 322;
determined by photoelectric methods, 328;
different kinds, 296;
different stages, 383, 384;
spectral type in relation to, 309
Magnolias, antiquity, xiii, 324-5;
development, 55;
fertilization, 130-1;
former distribution, xiv, 375;
fossil ancestor, xiii, 318;
index plants, i, 255;
in landscaping, xiii, 271-2
Mahogany, from tropical forests, xiv, 383;
in anacardiaceae family, xiii, 200
Maidenhair Tree, xiii, 315-16;
in landscaping, 271-3

Mail-Order Business, in stormy weather, i, 264

Maine, coast of, iii, 37-8, 57, 235, xiv, 256, 257, 262-3;
coast destruction, 46;
dikes on coast, iii, 110, xiv, 108;
harbors, 268;
moose of, xii, 318
Mains, electric, vii, 373
Maize, history and uses, xiii, 211-13
Major Triad (music), iv, 206-7
Make-and-Break (electricity), iv, 382
Malachite, iii, 334, 360
Malaise, sensation of, ix, 91
Malaria, x, 153-9;
campaign against, 173-4, 299-301;
control of, in tropics, xiv, 356, 357;
former idea of causes, x, 286;
quinine and, xiii, 250-1
Malaspina Glacier, iii, 70

Malay Archipelago, bananas native to, xiii, 216;
continental relationships, xiv, 274;
crocodiles of, xii, 201;
lemurs of, 374, 375;
largest flower in, xiii, 363-4;
parrots of, xii, 266;
rain forests, xiv, 369
Malay Peninsula, beriberi in, x, 257;
coco palm of, xv, 125;
leaf butterfly of, xii, 117;
rhinoceros of, 306;
snakes of, 214, 218;
tapirs of, 306;
tin production, iii, 369
Malays, hair of, xv, 37;
immunity to tuberculosis, 51;
in tropics, xiv, 356;
members of brown race, xv, 37
Malic Acid, viii, 222-3, 336
Malicious Animal Magnetism, xi, 311
Malleable Iron, v, 319
Malleability, viii, 126;
in mineral identification, 202
Mallow Family, xiii, 200
Malmags, xii, 374

Malpighi, Marcello, x, 77, xvi, 107, 112, 116, 126

Malt, viii, 249
Malta Fever, diagnosis of, x, 216
Maltase, viii, 357
Maltose, viii, 227, 241, 243, 244;
in brewing, 249;
formed in digestion, ix, 230
Mammals, xii, 270-384;
Age of, iii, 20;
appearance in Cretaceous, xv, 71;
egg-laying, 272-3, 274;
evolution of, xii, 185, 271-2;
geological history, iii, 20, 297-306;
growth in relation to flowering plants, 257;
in oceanic islands, xiv, 277-8;
order of succession, xii, 338-9;
primitive types, 272-4;
smallest of, 368;
temperature maintenance in, ix, 307-8;
warm-bloodedness of, 305, 306
Mammato-Cumulus Clouds, i, 104, 376
Mammoth Cave, iii, 127, xiv, 148;
fishes of, xii, 163
Mammoth Coal Bed, iii, 201, 347-8

Mammoth Hot Springs, terrace, iii, 192 (Pl. 11);
travertine deposits, 325, xiv, 146
Mammoths, xii, 301 (fig.), 302;
of Ice Age, xv, 76, 79;
prehistoric pictures of, 85, 86;
remains found in Siberia, 16
Man, activities of, ix, 21;
adaptation to environment by, xiv, 344, 363, xv, 25, 26, 28, 31, 36;
adapted to mixed diet, ix, 246, 285;

Age of, iii, 20;
anthropology science of, xv, 10-11, 15, xvi, 36;
antiquity of, ii, 19, iii, 301-2, 303, v, 11, xv, 11-12, 69-87, 95, 163;
apes and, physically compared, xii, 373, xv, 57-62, 94;
brain in, 39-41, 62-3, 96;
broadened interests of, x, 10;
cell development in, ix, 44;
chromosome number in, 46, 339;
dependence on fire, shelter and clothing, 308-9;
descent of, 349, xii, 384, xv, 56;
distribution over earth, xiv, 21, 344, xv, 12;
distribution mostly on plains, xiv, 218-19;
dominant impulses, xv, 185;
educability, 66;
embryological development, 53-5;
environmental control of, xi, 33, 58, xiv, 30-1;
environment conquest by, xv, 25-6;
environment of present, x, 354;
erect posture and walking, xv, 58;
evolution of, iii, 283, 301-6, xv, 25, 26-31, 53-4, 70, 88-102;
evolution, Anaximander on, xvi, 78-9;
face and brain case in, xv, 43;
fear in, origin of, xi, 136;
fire generation confined to, ix, 308, xv, 229-30;
fundamental instincts, xi, 50-6;
grasp of, ix, 67-8;
grouping tendency in, xv, 361-3;
improvement by selection and education, xvi, 157;
impulses conscious, xv, 273;
increase in numbers, 26-7;
infectious diseases peculiar to, x, 206;
instincts and reason in, xv, 65-6, 68;
language evolution, 140, 142-3, 146-63;
language importance, ix, 152-3, xi, 224;
"measure of all things," xvi, 85;
origin of, various accounts and theories, xv, 69-70;

Paracelsus on, x, 48;
physical, xv, 32-52;
physical measurements, comparative, 57;
place in nature, iii, 260, 281, xvi, 126;
primate, xii, 373;
psychological unity, xvi, 42-3;
races of (see Races);
rate of growth in, ix, 32 (diagram);
reasoning power, xi, 237, 243-4, xv, 65, 66, 68;
relation to lower animals, 53-68;
rudimentary structures in, 56;
sense of smell, xi, 77-8;
sex determiners in, ix, 338-9;
skull capacity, xv, 40-1, 89;
skull shapes in, 42-3;
stages in development of, 188-204;
structure compared with apes, 57-62;
struggle for existence in, 25-6, 27;
struggle for perfection in, 28-9;
survival of fittest in, 27;
symmetrical instinct in, 251;
tool-using animal, v, 9, 10-11, ix, 67-8, xv, 205;
tropical animal, ix, 308-9
(see also Primitive Man)
Manatees, jaguars and, xii, 362
Mandan Indians, buffalo dance, xv, 305-6
Mandibles, of insects, xii, 99;
of men and apes compared, xv, 94
Mandrills, xii, 379-80
Mangabeys, xii, 379
Manganese, viii, 154;
affinity strength, 128;
atomic weight and symbol, 383;
electrochemical analysis, 295;
fusibility, 384;
ores, 198, 271;
specific gravity, 384;
test for, 287, 289
Manganin, resistance, vi, 77, vii, 364
Mangrove Keys, xii, 42
Mangle, Electric, vii, 82-3

Manhattan Elevated Railway, engines and turbines, v, 152-3

Manholes, construction, vii, 30
Mania, hot baths in treatment of, x, 311;
of adolescence, 236-7
Maniacs, strength of, xi, 264
Manila Hemp, xiii, 236, 239-40
Manila Paper, source, xiii, 240
Manna, "rains" of, i, 355, 357
Mantids, xii, 107-8
Manual Labor, fatigue from, ix, 81;
food requirements in calories, 297
Manufacturing Centers, of future, v, 173
Manufacturing Stage, xv, 187, 203
Manures, as fertilizers, viii, 342-3;
as nitrogen source, xiv, 66;
waste of, viii, 346
Map-Making, aeronautical, i, 45-8
Maple Tree, antiquity, xiii, 324-5;
as forest tree, 86-7;
fruit, winged, 57, 58 (fig.);
in landscaping, 271-2;
petals absent in, 195;
seed dispersal, 343;
source of sugar, viii, 242-3;
in United States, xiii, 368, xiv, 372
(see also Sugar Maple)
Maps, discrepancies in, xiv, 10-11;
tinting of, iv, 130
Marble, iii, 371;
green, 338;
metamorphic rock, 380, xiv, 19;
reaction with acids, viii, 37
March (of weather elements), i, 205, 376-7
Marchetti, Peter, x, 79
Marconi, distress signal system, vii, 284;
wireless messages, 258, 259;
wireless work, xvi, 191
Marconi Transmitting System, vii, 263-5
Mare Tenebrosum, i, 55
Mare's Tail Clouds, i, 99, 377
Margarines, vegetable, x, 261, 267

Marine Animals, conditions necessary, iii, 17;
large, xii, 297-9, 333-5, 347;
mollusks, 57-80;
primitive types, 16-24, 26, 32, 128-9;
worms, 45, 51, 54
Marine Climate, i, 208, 377
Marine Deposits, iii, 52-5
Marine Meteorology, i, 271-83;
founding of, 216
Marine Rivers, xiv, 153
Marine Rocks, xiv, 19;
found above sea level, iii, 82-3, 85, 132, 235;
in mountains, xiv, 231
Mariner's Compass, iv, 253-4, vii, 365;
invention and improvements, vi, 29, 41-2
Mariotte, Edme, xvi, 110, 111;
law of, iv, 140
Markhor, xii, 325
Marmosets, xii, 376
Marmots, xii, 294-5

Marne, Battle of, defence of "Grande Couronne", xiv, 90;
soldiers asleep on retreat, xi, 286-7
Marne River, topographical features, xiv, 89
Marquette, Père, xiv, 192
Marriage, xv, 273-95, 364
Mars, (planet), ii, 227-34;
atmosphere, 228-32, 247;
canals, 235-41, 248;
distance, 235-6;
Kepler's studies, 50;
life on, 228-32, 237-8, 247-8;
"lucid" planet, 264;
motions and orbits, 50, 162, 163;
photographic study, 131, 132;
rotation period, 59, 377;
satellites, 241, 110;
size, 162, 163;
surface study, 238-9;
Tycho Brahe's studies, 49;
weight, 76, 77-8
Marshes, draining of, by trees, xiv, 379;
malaria and, x, 154, 300
Marsh Gas, iii, 345, 354, viii, 51;
as ignis fatuus, i, 347, 348
(see also Methane)
Marshmallow, family, xiii, 200
Marsupials, xii, 274-81;
evolution of, 271
Martens, xii, 350, 351
Martensite, viii, 274
Martha's Vineyard, waves action, iii, 56

Martin, Prof. E. G., author Physiology Vol. ix

Maryland, former volcanoes, xiv, 318;
oyster industry, xii, 61
Maskelyne, astronomer, xvi, 124;
mountain-weighing, ii, 68-9
Mass, defined, iv, 35, xvi, 130;
density and, iv, 110;
measured by beam balance, 102;
momentum in relation to, 62-3;
motion in relation to, 60-1, 63-5, 72, 78;
standard units of, 46, 69, xvi, 130;
weight and, iv, 35, 110, xvi, 130
Massage, ancient Chinese, x, 13;
effect on lymphatics, ix, 223
Massasauga, xii, 235
Mastoiditis, ix, 61-2
Matches, friction and safety, viii, 88;
invention of, xv, 232
Materialism, xi, 13-14;
in mediæval philosophy, x, 35
Materia Medica, Mesue's work on, x, 32;
17th century improvements, xvi, 109
Mathematical Astronomy, ii, 15, 113-14;
culmination of, 15, 71-2;
spectroscopic methods in, 119-24

Mathematical Calculations, development of, xv, 181-4, xvi, 61

Mathematical Machines, v, 326-7
Mathematics, coordinates used in, iv, 16;
Golden Age, ii, 15;
history of development, xvi, 54, 60-3, 68, 71-2, 79-81, 88-90, 92, 94-5, 103-5, 113-14, 118-19, 125;
practice of challenges in, iv, 89
Mather, Cotton, on disease, x, 380;
on inoculation, 101
Mating Instinct, xiii, 116
Mato Tepee, xiv, 129-30
Matter, chemical energy of, viii, 267;
chemistry, science of, 11, iv, 12;
constitution of, 21, 23, vi, 35-6, 78, 108, 109-12, viii, 22-8

(see also Atomic Theory, Electron Theory, Molecular Theory);
elasticity of, iv, 35-6;
elements of, viii, 11-12, 16-21;
energy and, iv, 12, 13-14;
energies in, xvi, 15;
energy loss, 134;
ether in, iv, 181;
fluxation idea, xvi, 194;
fourth state of, iv, 54-5, xvi, 193;
Greek theories, 77, 83-4, 86, 91, 118;
indestructibility, vi, 128, viii, 110;
inertia of, iv, 20;
kinetic theory of, 30, 131;
monad theory, xvi, 117-18;
primary concept, iv, 15, 16;
sciences of, xvi, 36-7;
states of, iv, 21-3
(see also Physical States)
Matterhorn, formation of, iii, 236
Matriarchy, xv, 295
Maudsley, Henry, inventions, v, 45-6, 99, 376
Mauna Loa, iii, 103-4, 107, xiv, 322-3;
real height and diameter, 101, 225
Maury, Lieut. M. F., i, 216, 271-2, xiv, 288
Maxim Machine Gun, v, 363, 364, 382

Maxwell, Clerk, electromagnetic theory, iv, 54, 55, vi, 25, vii, 371;
on loss of molecular energy, xvi, 134;
on motor-dynamo discovery, iv, 54;
on rings of Saturn, ii, 133, 265-6;
prediction of electromagnetic radiations, xvi, 191

Mayans, number and time systems of, xv, 181, 182 (fig.)

May Bugs, xii, 123
Mayflies, xii, 104
Mazama, xii, 325
Mazda Lamps, vi, 267, 268;
ohms of, 75;
sizes and light, vii, 153
Mazda Nitrogen Lamps, vi, 278
Meadow Pink, xiii, 133-5

Meals, agreeable surroundings, at, ix, 241, x, 319-20;
alcohol at, ix, 244;
bathing after, 313;
eating between, 88;
excitement at, xi, 374-5;
soup value at, ix, 241, x, 320;
water at, ix, 229
Meanders, iii, 380;
in old and new areas, 33, 34, xiv, 162, 165;
intrenched, 165
Measles, Brown's treatment of, x, 89;
consumption and, 292;
eardrum affected by, ix, 103;
epidemic of 15th century, x, 59-60;
first description of, 32;
germ of, 200;
Indian susceptibility to, xv, 48, 51

Measurements, British and metric systems, iv, 45-6, 69-70, viii, 27-8;
chemical apparatus, 294, 295 (fig.);
in different fields, vii, 151-2;
sciences and standards of, xvi, 129-31

Meat, body heat production by, ix, 309, x, 271, 273;
calories in, 269;
calory loss in preparing, ix, 299;
composition, viii, 362;
cooking effects, 368;
digestion of, x, 326;
eating of, effects, ix, 384-6, x, 279;
eating of, in relation to bile, ix, 275;
food constituents in, 300;
gristle of, 13;
proteins in, 34, 35, 280;
salted, tinned and dried, x, 263;
salts and extracts of, viii, 366;
structure of lean and coarse, ix, 75;
vitamines in, x, 260, 261, 262, 266
Mechanical Advantage, iv, 89, 92, 93

Mechanical Equivalent of Heat, iv, 49-50, 140, 142, 189-90, v, 350-1, viii, 186-7, xvi, 131-3

Mechanical Progress, summary, v, 376-84
Mechanics, Volume v
Mechanics, "artisan" of physics, iv, 50;
daily applications, xvi, 16-17, 19-20, 30;
defined, iv, 25;
history, xvi, 67-8, 72, 89, 91

Medical Education, requirements of, x, 367-8, 369;

Rockefeller Foundation and, 172
Medical Humanists, x, 45
Medical Meteorology, i, 316-31
Medicine, Volume x

Medicine, history of, x, 9-192, xvi, 59, 63, 70-1, 82-3, 95-6, 98, 106-9, 112, 126-7, 178-87;

Paracelsus on science of, x, 49;
science of, remarks on, 368, xvi, 15, 37
Medicine Men, xv, 349-53, 354, 359, 365-6

Medicines, electrical application of, vii, 247-8;
quack, 240-1;
plants used as, xiii, 249-55;
specific, x, 49-50

Mediterranean Lands, climate of, xiv, 348-9, 358-9;
source of cultivated plants, 381-2

Mediterranean Racial Group, xvi, 49

Mediterranean Sea, ancient civilization around, xiv, 290, 306-7, 358, 359;
concordant coasts, 249;
darkness at depths, 298;
geology of, 290-1;
petrels of, xii, 252;
"pilgrim shell" of, 65;
salt in, viii, 139, xiv, 296, 297;
sponges of, xii, 32;
temperature of waters, xiv, 299
Mediterranean Volcanic Belt, xiv, 316-17
Medium, technical meaning, iv, 382
Medulla, xi, 28, 29, 76
Medusae (jellyfish), xii, 36
Megabar, iv, 123
Megaphones, iv, 239-40
Megatheres, xii, 283
Melampus, xii, 68-9
Melancholia, of adolescence, x, 236-7
Melancholic Temperament, xi, 153, 205
Melanesia, xiv, 277
Melanesians, beards of, xv, 38;
hair of, 38
Melting Point, iv, 153;
chemical composition and, viii, 298-301;
of various substances, iv, 161-2;
pressure and, 153, 162, 163-6

Membranes, fluid equalization through, ix, 194, xiii, 90-1;
vibrations of, iv, 101
Memory, xi, 208-17, ix;
association of ideas in, 149-51;
delayed nervous disturbances in, 141-2;
of emotions, 154;
hypnosis and, xi, 317-18;
reason and, 243-4;
right use, 378;
seat of, in cerebrum, ix, 145, 146-7
Memory Colors, xi, 89, 220-1
Men, basal metabolism of, x, 271;
brain in, xv, 39;
color-blindness in, ix, 116, 340-1;
hats of, x, 309;
heart rate in, 334;
height of, xv, 38;
skull capacity, 40;
susceptibility of, x, 240;
voice vibration rates in, ix, 99
Mendel, Gregor, x, 231-2, 13, 333, xvi, 154;
experiments on peas, ix, 328, 333-4
Mendel's Law, xiii, 333, xvi, 157
Mendeléeff, chemical work, xvi, 134, 163;
classification of elements, viii, 177;
prediction of elements, 180
Mendelian Theory, xvi, 156
Mental Activity, insomnia due to, ix, 219;
seat of, 145-6;
temperature effects, i, 323-4
Mental Fatigue, ix, 137-8, x, 247, xi, 269
Mental Healers, x, 242-3, 365
Mental Hygiene, xi, 368-82
Mental-Nerve Diseases, x, 353
Mental Processes, in brain, ix, 145, 147-54;
similarity in all men, xvi, 42-3
Mental Tests, in diagnosis, x, 371;
in vocational guidance, xi, 359-60
Mental Types, xi, 152-9
Mercaptan, smell of, xi, 80
Mercerized Cotton, viii, 255
Mercuric Chlorides, viii, 170, 333
Mercuric Mercury, test for, viii, 287, 288
Mercuric Oxide, instability, viii, 101;
oxygen preparation from, 34, 170
Mercurous Mercury, test for, viii, 288

Mercury (metal), affinity intensity, viii, 128;
atomic weight and symbol, 383;
barometric column of, iv, 30;
compounds, viii, 170;
density of, iv, 113;
electrical conductivity, 283;
expansion by heat, 135;
freezing point, 153;
heat capacity, 155;
light of, viii, 172;
melting point and requirements, iv, 162, viii, 384;
ores and production, iii, 370, viii, 198, 270;
properties and uses, iii, 370, viii, 126-7, 170;
specific gravity, 384;
specific heat, iv, 155;
use of, in syphilis, x, 60, 104;
use of, in thermometers, iv, 135, 137, 153
Mercury (planet), ii, 189-90;
atmosphere, 190, 246;
life on, 245-6;
"lucid" planet, 264;
motion at perihelion, 79, 81;
non-rotation theory, 377;
orbit, 39, 73, 162, 163;
size, 162;
weight, 76, 77
Mercury Arc Converters, vii, 365
Mercury Arc Lamp, vi, 281-3
Mercury Arc Rectifiers, vi, 331, 333-9
Mercury Fulminate, viii, 145
Mercury Vapor, viii, 309
Mergansers, xii, 257
Mergenthaler Linotype, v, 308-10, 381-2
Meridian Photometer, ii, 297
Mesaba Range, iii, 358
Mesas, iii, 140, 380, xiv, 81, 82
Mesenchyme, xii, 26-7
Mesentery, ix, 59
Mesopotamia, ancient empire of, xiv, 306;
astronomy of ancient, xvi, 70;
British campaign, i, 308;
cradle of human race and history, xvi, 46, 51;
food plant center, xiii, 221, xiv, 381-2;
mirage in World War, i, 173;
ostriches of, xii, 249;
photographic mapping, i, 47;
present desert character, xiv, 219;
scurvy in, during World War, x, 265;
wild wheat of, xiii, 210
Mesozoic Era, iii, 20, 208-20;
animal life in, 270, 272, 275, 285, 286;
birds of, xii, 239, 242;
divisions and species of, xv, 71;
mammals of, iii, 297, xii, 271;
marsupials in, 277;
plants of, iii, 255, 256, 257;
reptiles of, 286-95, xii, 183, 188, 194-5, 202-3;
sharks of, 143

Messages, primitive methods of sending, xv, 165-7

Messina Earthquake, xiv, 340-1
Mesue of Damascus, x, 32
Metabolism, ix, 37, x, 268;
calculation of, 269-70;
daily total in calories, ix, 296, 297;
disease in relation to, 302-4, x, 268-81;
fatigue caused by, ix, 80, 81;
food requirements for, 289, 295-301;
protein, x, 277-80;
protein effects on, ix, 301-2;
rate of, how influenced, x, 270-1;
studies of, 128, 382;
temperature effects on, ix, 37, 306-7

(see also Cell Metabolism, Basic Metabolism, Functional Metabolism, Growth Metabolism)

Metal-Bearing Deposits, iii, 355-70

Metallography, vi, 78, viii, 273-4, xvi, 175-6

Metallurgy, viii, 269-74;
historical development, xvi, 51, 59, 74, 174-7

Metals, viii, 17, 126-74, 379;
affinities (electromotive series), 127-9;
affinity for sulphur, 76, 77;
atomic weights, vii, 384, viii, 383;
atomic weights in relation to activity, 133, 180;
chemical analysis, 286-9, 291-2;
colors of compounds due to, 312;
common states of, iv, 153;
compounds of, viii, 130, 146, 202;
corrosion of, 13, 100;
cutting of (see Cutting of Metals);
electrical conductivity, iv, 259;
electrification of, 257, 259;
electrochemical analysis, viii, 295;
electromotive positiveness, vi, 59;
expanding on solidifying, iv, 150;
extraction from ores, viii, 131, 269-72;
groups of, 181-2;
heat conductors, iv, 177, 178-9;
identification of, viii, 201, 202, 313;
industrial, 154;
internal structure, vi, 78-9;
in body, viii, 354;
in sea, 197;
melting point and requirements, iv, 162;
melting points, viii, 384;
occurrence, 129-31, 198-200;
occurrence due to igneous action, xiv, 234, 237-8, 329;
original form in earth, viii, 193;
periodic classification, 180-1;
plant uses of, 337, 341;
positive ionization of, 122;
potentials against hydrogen, vii, 383;
rare earths, viii, 182;
refining of, 272;
refining, electrolytic, vii, 319-21;
resistance (electrical), vi, 77-9;
resistance tables, vii, 384;
resistance reduced by low temperatures, i, 32;
specific gravity table, viii, 384;
thermoelectric powers, vii, 383;
valency, vii, 384;
welding by oxyacetylene blowpipe, 33;
X-ray examination, vii, 257
Metamorphic Rocks, iii, 13, 380, xiv, 18-19;
jointing of, 133;
land forms in, 44, 113;
ores in, 234, 237
Metamorphism, iii, 380;
by molten intrusions, xiv, 112;
fossils and, iii, 265
Metazoa, xii, 25, 26-7
Metchnikoff, x, 143, 201, 209-10, xi, 218
Meteoric Dust, i, 53, 56;
in deep-sea deposits, xiv, 285
Meteoric Iron, ii, 292
Meteorites, ii, 290-3;
energy from, ix, 25;
iron and dust from, iii, 55;
origin of life from, xii, 9
Meteorograph, i, 88, 377
Meteorological Instruments, i, 68-89;
public display, 266-7

Meteorological Observations, history and organization, i, 212-23;
marine, 272-3, 274-6
Meteorological Terms, i, 365-84
Meteorology, Volume i
Meteorology, daily interest, xvi, 13;
defined, i, 7, 377, xvi, 37;
history of development, 114, 177;
organized, i, 212-23
Meteors, ii, 283-9;
carborundum found in, vii, 310;
cause of brontides, i, 196;
dust from, i, 53, 56;
former meaning, 7;
in relation to corona, ii, 224, 225;
in relation to solar system, 164;
orbits, 287, 288, 289;
photographic study, 134-5;
planetesimal theory, iii, 162
(see also Meteorites)
Meter, length unit, iv, 46, 69, viii, 27-8;
radio unit, vii, 272;
value in yards, iv, 70
Methane, viii, 51, 206;
combustion products, 61;
derivatives, 210, 230-1;
flame of, 60;
name of, 98
Methodism (medical), x, 26, 28, 29
Methyl, defined, viii, 379
Metric System, iv, 46;
adoption in French Revolution, 136;
advantage in specific measurements, 111;
units in, iv, 69-70, 80-1, 154, viii, 27-8
Meuse River, xiv, 89;
delta and shifts, 186
Mexico, ancient civilization (see Aztecs);
century plants, xiii, 355;
chocolate cultivation, 234;
climatic belts, xiv, 223;
copper production, iii, 360;
corn-growing in ancient, xiii, 212;
deserts of, xiv, 380;
first hospital, x, 81;
harbors and commerce, xiv, 265-6;
jaguars of, xii, 362;
lava fields, iii, 228;
lead production, 362;
new volcanoes in, xiv, 320;
oil output, iii, 350, 354, v, 173;
plateau and hot lands of, xiv, 221, 223;
rivers of, 195;
rubber plants, xiii, 248;
serpents of, xii, 214, 234, 235;
silver production, iii, 367-8;
vanilla production, xiii, 260;
yellow fever in, x, 163

Mexico, Gulf of, importance in rainfall distribution, xiv, 360;
sponges in, xii, 32
Meyer, Lothar, xvi, 163;
classification of elements, viii, 177
Mica, iii, 334;
in granite, 308;
chemical composition, viii, 90, 193
Mice, xii, 289-91;
snakes and, 220, 227
Michelangelo, anatomical work of, x, 51-2
Michelson, interferometer, ii, 151, 322-3;
standard length measurements, xvi, 130

Michigan, copper production, iii, 327, 360, 361;
gypsum deposits, 376;
iron ores, 357;
salt deposits, 375
Michigan, Lake, size, xiv, 204
Micron, wave length unit, iv, 359
Microline, iii, 328
Micrometer, use of, ii, 58, vii, 151
Micronesia, xiv, 277
Microscopes, iv, 343-4;
in chemical analysis, viii, 290-1;
in medicine, x, 67, 128, 132, xvi, 112-13
Middle Ages, astronomy in, ii, 37-41, 42;
comets of, 273;
constructive work, 12;
ermine fur in, xii, 350;

European commerce in, xiv, 240, 241, 307, 308;
falconry of, xv, 223;
hail and lightning prevention, i, 341;
hysteria epidemics in, x, 360;
intellectual character of, 34, 35, 43;
intellectual lethargy, ii, 11;
Jewish polygamy of, xv, 289;
magic, xvi, 79;
medicine in, x, 31, 34-42, 43;
meteoric showers of, ii, 287;
minstrels of, xv, 323;
painting in, 302-3;
poisoning in, 228-9;
science in, iv, 27-8;
science and philosophy, xvi, 99-105;
views of fossils in, iii, 14
Migrations, of birds, xii, 258, xiii, 55;
of forests, xiv, 375-6;
of plants, xiii, 348
Mikulicz-Rodecki, xvi, 183
Mil, wire measure, iv, 283, 382, vii, 373
Mil Foot, vi, 77
Military Meteorology, i, 306-15
Milk, amino acids in, x, 278;
boiling of, viii, 368;
calories in, ix, 299;
composition, value and products, viii, 363;
contamination and safeguarding of, ix, 347;
digestion of, 235, 292;
fat globules of, viii, 315;
food constituents in, ix, 300;
for infants, 33-4, 346-7;
germs in, x, 193;
milk sugar in, viii, 227;
pasteurized, x, 139-40, 263, xiii, 71, ix, 347;
snakes and, xii, 222-3;
sour, and longevity, xiii, 172;
souring of, 71;
souring, lactic acid developed, viii, 223;
typhoid fever from, x, 287, 288;
vitamines in, 259, 260, 261, 262, 263, 266;
vitamines and lime salts in, ix, 33-4, 347;
water in, how measured, iv, 113
Milking Machines, vii, 227
Milk Sugar, viii, 226, 227, 363;
digestion of, ix, 292
Milkweeds, flowers, xiii, 50;
plumes, 343-4
Milky Way, ii, 350-6;
discovery of separate stars, 96;
Egyptian knowledge of, xvi, 69;
Galileo's observations, 103
(see also Galaxy)
Miller, Hugh, xvi, 169
Miller, Prof. W. J., author Geology, Vol. iii
Milliken, Dr., vi, 121
Milling Machines, v, 47, 53, 378, 381
Millipedes, xii, 87, 88-9
Mills, Milling, development of, xv, 237-41
Mind, activities of, xi, 12, 25, 32, 236;
body and, relations, 13-14, 61, 369-75;
care and right use, 375-82;
character of a good, 377-80;
complexity, 206;
conscious and subconscious, 47;
differences and classes of, 152-9;
difficulty of study of, x, 356;
diseases of, 354-63;
dominant traits, xi, 208-9;
Emerson on common, 152;
environment effects on, x, 237, 242-4;
fatigue of, xi, 269;
impairment by physical ills, 369-75;
kinetic theory, 57-61, 123;
meaning, 12, 13, 23-5, 32, 236;
mechanism, meaning, 12-14;
origins, 45;
psychology as science of, 10-14;
qualities revealed in smiles, 357;
similarity in all men, xvi, 42-3
Mind of the Crowd, xi, 323-33

Mineral Matter, in animal and plant tissues, viii, 354-5;
in ground water, xiv, 142-3, 144;
in human body, viii, 348;
in plants, 337, 339, 341, xiv, 65-6;
in sea and surface waters, iii, 52, 127;
in soils, viii, 338, 339, xiv, 68-9
Mineralogy, iii, 307-41, viii, 200-3;
daily interest, xvi, 23, 29;
defined, 38;
history of development, 112, 126, 169, 173

Minerals, concentrations of, viii, 192, 195-200, xvi, 173;
definition, iii, 307-8, 380, viii, 192, 200, 379;
description of various, iii, 321-41;
distinguished from living things, xii, 13-14;
groups of, viii, 200-1;
number of species, iii, 308, 315, viii, 200;
properties and identification, iii, 309-21, viii, 201-3, 313;
silicates, importance, viii, 193;
veins, how formed, iii, 126

Mineral Salts, need of, in food, x, 256, ix, 33

Mineral Springs, xiv, 142-5;
limestone deposits of, 146
(see also Hot Springs)
Mines, Mining, coal dust explosions, i, 63;
compressed air uses, 26, 27, iv, 129;
deep shafts, iii, 120, v, 259-60;
explosions caused by oxygen, i, 322, xiv, 12, 15;
hot water in, 144;
importance of faults, iii, 88, xiv, 37;
mountains and, 237-8;
oxygen in air, i, 322;
science of, xvi, 36;
temperature limitations, xiv, 15;
underground water in, iii, 116;
water-blasting in, v, 100

Mining Machinery, compressed air in, v, 128-9;
sonic wave transmission, 108
Mining Schools, xvi, 126
Mink, xii, 349, 350
Minnesota, iron ores, iii, 357-8;
lakes and lake basins, xiv, 200, 212;
newness of topography, 158;
moose of, xii, 318
Minnows, xii, 161, 163
Minstrels, mediæval, xv, 323
Mint Family, xiii, 204;
petals in, 190
Miocene Epoch, iii, 221;
species surviving from, xv, 71;
tortoise of, xii, 191
Mira, classification, ii, 115;
oldest known variable, 325
(see Omicron Ceti)
Mirages, i, 172-4, 377, iv, 328-9
Mirrors, ancient, v, 109-10;
fire generation by, xv, 232;
images formed by, iv, 335-7;
making of, viii, 171
Missing Link, xv, 56, 91
Mississippi-Missouri System, xiv, 153, 189
Mississippi River, aerial mapping, i, 47;
course changed, iii, 98;
delta, xiv, 53;
depth and dredging at mouth, 270;
discovery and exploration, 192;
flood plain slope, 162;
former steamboats, 193;
harnessing of, v, 81-3;
in American history, xiv, 192-3;
meanders of lower, 162, 165;
mineral matter in solution, iii, 127;
overflow question, xiv, 71;
paddle-fish of, xii, 151;
salt content, viii, 139;
sediment carried by, iii, 31, xiv, 53;
upper, superimposed, 171

Mississippi Valley, alluvial soils of, xiv, 71;
bowfins of, xii, 152;
coal fields, iii, 348;
development due to rivers, xiv, 31;
earthquakes of 1811, 203;
forests of, 378;
French in, 192;
geological history, iii, 35, 182-3, 187, 195, 206, 207, 231;
growth of population, xiv, 193;
loess deposits, i, 54, xiv, 72;
panthers formerly in, xii, 363;
precipitation in, xiv, 360;
thermal springs absent, 143-4;
thickness and composition of strata, 228-9;
turtles of, xii, 187, 193;
volcanic action in, xiv, 318;
yellow fever epidemic, x, 160
Mississippian Period, iii, 20, 197-8, 380;
animals of, 268-9;
plants of, 252-3;
sea extensions in, 193
Missouri, Ice Age in, iii, 239;
loess deposits, xiv, 72;
mining products, iii, 362, 364;
sunk country, 98
Missouri River, course changed, iii, 245;
in western emigration, xiv, 195;
upper Mississippi, xiv, 153
Mist, i, 377, Brocken specters in, 184-5
Mistakes, analysis of, xi, 340, 379
(see also Errors)
Mistletoe, xiii, 15, 100
Mistpoeffers, i, 195, 377
Mistral Winds, i, 133, 377
Mitchell, John, x, 116
Mitchell, Mount, xiv, 97, 168
Mites, xii, 98
Mixtures, compared with compounds, viii, 15;
explosions of, 62;
heat and cold production by, iv, 174-5;
separation by vapor pressure, viii, 305
Mizar, double star, ii, 123, 334
Mocking Bird, xii, 269
Modesty, clothing and, xv, 253;
custom and, 254-5
Mohammed Ibn Musa, xvi, 103
Mohammedan Astronomy, ii, 37-9
Mohammedanism, development of, xv, 199;
polygamy allowed by, 289
Mohawk Valley, importance of pass, xiv, 194;
origin, iii, 232;
rock faulting, 91
Moissan, electrical work, xvi, 176;
Arc Furnace, vii, 303

Moisture (atmospheric) climate determined by, xiv, 351-6;
temperature effects, 352-4;
vegetation determined by, 364, 366, 372, 377-8, 380, 381;
atmospheric (see Humidity)

Molar Solutions, viii, 118-19, 379

Molasses, production and use, viii, 242, 243, xiii, 215;
vitamines in, x, 262
Mold, cause of formation, i, 61;
disease-producing, x, 196;
reproduction, xiii, 164
(see also Fungi)
Molecular Theory, viii, 23-5;
history of development, xvi, 91, 133-4
Molecular Weight, viii, 92;
boiling point and, 299-300;
diffusibility and, 108;
differences, to what due, iv, 110;
found by vapor pressure, viii, 305;
in relation to actual weight, 109;
of proteins, 351
Molecules, iv, 21, vi, 109, viii, 379;
arrangement in relation to crystals, 203, xvi, 164;
attraction of, viii, 306;
possible variations in, iv, 143;
condition at absolute zero, iv, 142-3;
discrimination from atoms by Dumas, xvi, 162;
dissipation of energy, 134;
electrical balance and unbalance, i, 142, 143;
electrical charges of, viii, 121;
escape from liquids, iv, 167;
ether in, iv, 181;
formulæ of, viii, 91;
fundamental vibrations of, iv, 363;
in solids, liquids and gases, iii, 309, iv, 22, 131-3, 152-3, 363, viii, 23-4, 106;
in solutions, 311-12;
invariability law, 110;
laws of, 106-10;
magnetization of, iv, 245, 253;
momentum, viii, 109-10;
monatomic, 309;
motions of, iv, 132-3, 363, viii, 23-5, 305-6;
motion increased by heat, iv, 138-9, 144, 152-3, viii, 25, 37-8, 107, 108, 309, 310;
number, vi, 112;
number of, in gases, iv, 133, viii, 25, 108-9;
polymerization, 219;
size, vi, 112, viii, 24, 306;
structure, 25-7, 306;
structure, chain and ring, 233;
structure, ether, 217, 224;
structure in hydrocarbons, 51;
structure in proteins, 351;
structure and color, 258, 259, 312;
structure and physical state, 207, 298;
structure in relation to boiling and freezing points, 298-9;
structure revealed by polariscope, 309;
velocity of, iv, 133, viii, 24
Moles, xii, 366, 367-8
Molluscoids, iii, 259, 263, 270;
origin of name, xii, 47
Mollusks, iii, 260, 272-6, xii, 57-80;
deep sea, 23;
in sea plankton, 19;
sponges and, 32

Molybdenum, atomic weight and symbol, viii, 383;
use and occurrence, xiv, 238
Moments of Force, iv, 382
Momentum, iv, 62-3, 66-7
Monadnock, Mount, iii, 232
Monadnocks, iii, 35
Monads, xvi, 117, 118
Mondeville, Henri de, x, 39, 40
Mongolian Orongo, xii, 327
Mongols, hair of, xv, 37, 38 (fig.);
in yellow race, 37
Mongooses, xii, 351, 352
"Monitor," Ericsson's, v, 380
Monitors (lizards), xii, 208
Monkeys, xii, 376-9;
embryological resemblances, xv, 54;
expression of feelings by, 64-5;
fear in, xi, 136;
feet of, iii, 301 (fig.), xv, 61;
first appearance, iii, 301;
jaguars and, xii, 362;
lemurs and, 374, primates, 373;
resemblance to man, xv, 57;
thumb in, 60
Monkshood, xiii, 196;
aconite from, 252
Monochord, xvi, 82
Monocotyledons, defined, xiii, 60;
evolution, 181;
families, 181-9;
first appearance, 319;
leaves and flowers, 176, 179;
stem formation, 177 (fig.);
relative antiquity, 207;
subdivisions, 179, 180
Monoecious Plants, xiii, 46
Monogamy, xv, 285, 289-94, 295;
among birds, 276-7
Monorail Car, v, 342-3
Monosaccharides, viii, 223-6
Monotony, of work, xi, 275-6, 277-8, 280
Monotype, v, 310-12, 383
Monros, physicians, xvi, 179, 181, 186
Monsoons, i, 130-1, 377, xiv, 350-1;
conditions resulting from, 359-60;
use of, in early trade, 307
Montana, bad lands of, xiv, 82;
fossils found, iii, 250;
grasslands and cattle, xiv, 222-3;
mining products, iii, 360, 361, 364, 368
Montauk Point, birds at, xiii, 342
Mont Cenis Tunnel, xiv, 240, 241;
drills used, i, 27
Montenegro, mountaineers of, xiv, 243
Monte Nuovo, eruption of, xiv, 316, 320
Montpellier, University, x, 36, 38
Montreal, harbor of, xiv, 270
Moodus, Conn., brontides, i, 196, 360
Moon, ii, 193-205;
acceleration of, iv, 98;
atmosphere, ii, 200, 204, 232;
coronas, i, 183;
distance, ii, 64, 197-8;
earthshine on, 41;
eclipses, 32, 206-8;
erratic amplitude, 25;
falling motion, 64, 65;
Galileo's studies, 54, 96, xvi, 103;
Halley on motions of, ii, 87;
halos, i, 100, 103, 178, 180, 181;
Hevelius's studies, ii, 57;
influences of, 201;
irregularities in motions, 32, 34, 73-4;
life on, 204-5, 247;
light and heat of, 168, 200;
light of, Egyptian knowledge, xvi, 69;
non-rotation theory, ii, 376, 377;
path around earth, xiv, 292-3;
photographic studies, ii, 130;
quartering, 28, 194-5;
size, 198-9, 230;
size as observed by ancients, 27-8, 32;
solar corona and, 221, 222;
spectrum lines, 112;
stereograms of, xi, 181;
telescopic views of, iv, 346;
theories of origin, ii, 375-6;
tides caused by, 70;
tides caused by, xiv, 291, 292-3
Moonbeams, measurement of heat of, iv, 301
Moon Dogs, i, 180, 377
Moon-Pillar, i, 376
Moonstone, iii, 329
Moor Fires, i, 56
Moors, astronomy of, ii, 11, 38;
in Mediterranean group, xvi, 49;
medical influence of, x, 37-8;
science of, xvi, 100, 106
Moose, xii, 318-19;
antlers of, 316
Moraines, iii, 67-8, 380, xiv, 59;
lakes formed by, iii, 144-6, xiv, 202
Morality, beginnings of, xv, 356;
civilization and, xvi, 43-4, 45, 47-8;
primitive, limited to tribes, xv, 374;
religion and, 355-7;
varying conceptions of, 285-6
Morgagni Giovanni, x, 97-8
Moriceau, François, x, 79, 80
Morning Glories, climbing stems, xiii, 27;
roots, 18;
tendrils, 111
Moro, Lazzaro, xvi, 126
Morphine, xiii, 253;
an alkaloid, viii, 240;
use of, in pain, x, 381
Morro Velho, mine shaft, v, 259-60

Morse, S. F. B., telegraph inventor, vi, 24, vii, 108, xvi, 188

Morse Systems, vii, 108, 109-11
Mortar, lime in, viii, 150
Mortar and Pestle, xv, 238
Mortars (military), v, 368
Mortmain, meaning, xi, 44

Morton, William, ether introduction, x, 124-5, xvi, 185

Mosaic Laws, medical importance of, x, 15
Mosasaurs, iii, 288, xii, 203
Moselle River, xiv, 89, 90, 165
Mosenthal's Test, x, 379
Mosquitoes, campaign against, x, 299-301;
in fly family, xii, 120;
kinds of, x, 156;
malaria spread by, 154, 156-9, 299-301;
singing of, cause, xii, 103;
yellow fever and, x, 160, 161-2, 173
Moss Animals, xii, 46-7
Mosses, alternation of generations, xvi, 166;
character and kinds, xiii, 68-70;
reproductive process, 160-3
Mosso, Prof., experiment of, xi, 285;
on mountain sickness, i, 328
"Mother Carey's Chickens", xii, 252
Mother-Family, xv, 295
Mother-of-Pearl, xii, 63;
iridescence of, 245
Mother Shipton, iv, 104
Mothers, rule of, under polyandry, xv, 294-5;
transmission of hereditary traits, ix, 340-1;
transmission of nervous influences, 343-4
Mother's Milk, infants' digestion of, ix, 346
Moths, xii, 114-16, 118-20;
appearance in Tertiary, 104;
evolution of, 107;
in flower fertilization, xiii, 142-3;
number of species in New York, xii, 99;
Pronuba, adaptation in, xvi, 152-3
Motion, as sign of life, ix, 9-11, 14;
bodily, different kinds of, 82-3;
of animals, means of, 73-4;
sense of, ix, 90, xi, 123-8
(see also Movement)

Motion (mechanics), energy of (see Kinetic Energy);
force in relation to, iv, 56-69, 71-2, v, 182-3;
forms of, iv, 85-6;
Galileo's investigations, iv, 19;
laws of (see Newton's Laws of Motion);
quantity of, iv, 62;
rapid, not explained by Newton's theory, ii, 80, 81;
relativity of, iv, 16-17, xvi, 85;
science of, iv, 25;
time and, Newton on, 15;
uniform and difform, ii, 80;
Zeno's theories, xvi, 84-5
Motor Cycles, cooling of cylinders, v, 160;
gyroscopic action, 343;
generators in, vi, 215-16
Motor-Generator Sets, vi, 332-3, 342-3;
efficiency in electric furnaces, vii, 306
Motor-mindedness, xi, 222
Motor Nerve Cells, ix, 125, 126, 129, 160;
connections, 130 (fig.), 131, 147, 148 (fig.)
Motor Nerves, at birth, ix, 348
Motor Neurones, xi, 21, 22, 24;
development in embryo, 34, 35
Motor Response, defined, xi, 123-4;
method of, 26-7;
sensation dependent on, 27-8, 43, 63, 66, 74-5, 102-3, 110-11, 118-21, 202-3;
to contact and distance senses, ix, 95, 121, 140;
violence in emotions, xi, 134

(see also Final Common Path, Reactions, Reflex Actions)

Motors, iv, 308-9, vi, 217-63, vii, 367, 373;
advantages over engines, 223;
air-driven, v, 129-30;
alternating-current, vi, 240-63;
automatic regulation, 218, 224-9, 232;
automobile, v, 156-61;
compressed-air effects, 128;
compression and non-compression, 157;
constant-speed, vi, 231;
direct-current, 217-39;
direction of revolutions, 56;
earliest form, 21;
efficiency, 228;
efficiency in cold weather, vii, 194;
electromagnetic, vi, 95-6;
for farm purposes, vii, 223-4, 225-6, 228;
heat, Clausius's principle, xvi, 135;
individual machine, vii, 52;
in household appliances, 74, 78, 83-4, 86;
interchangeability with dynamos, iv, 54;
multiple cylinder, v, 159;
of electric cars, vii, 182-3, 185, 186;
of electric locomotives, 196, 200;
popular applications of, iv, 10;
power, on what dependent, vi, 223;
ratings, 192-4;
self-regulation of voltage, 226-8;
single-cylinder, v, 157;
speed variation and constancy, vi, 240-1;
starting and starters, 235-9, 250-5, 262-3;
synchronous, 241;
three-phase system, 206-7;
torque of, iv, 309, vi, 224-7;
toy, 95-9;
voltage generated, 247;
water and air-cooled, v, 159-61;
waterproof in U. S. Navy, vii, 332
Motor Tractors, v, 214, 215-218, 243
Motor Trucks, v, 214;
advantages to farmers, vii, 231;
growing use, 195
Motor Type of Men, xi, 155, 157, 158-9
Mott, Valentine, x, 121-2
Motus Peculiaris, ii, 346
Mound Builders, weaving of, xv, 248 (fig.)
Mountain-and-Valley Breezes, i, 131, 132, 377
Mountain Goats, xii, 325
Mountain Health Resorts, i, 322
Mountain Lions, xii, 363
Mountain Observatories, ii, 139-51
Mountain Passes, formation of, xiv, 58, 176
Mountains, Mountain Ranges, xiv, 224-6;
atmospheric pressure on, i, 28, iv, 114-15, 170, ii, 245;
block, iii, 138-9, xiv, 117, 226;
boiling point of water on, viii, 303;
Brocken specters, i, 184-5;
cirques of corries on, xiv, 58;
civilization of, xv, 129-31;
cloud caps and banners, i, 104-5;
coast lines and, xiv, 248, 249;
distinguished from plateaus, 28;
economic importance, 237-9, 245;
ephemeral character, iii, 11, 12, 130, xiv, 235;
faulted, iii, 138-9, xiv, 226;
folded, iii, 131-8, xiv, 36, 93-4, 96, 226-34;
forests on, xiv, 238-9;
formed by erosion of plateaus, iii, 139-40, xiv, 225, 226;
formation complex, iii, 140-1;
granite cores of, 112, xiv, 110-11;
heights determined by barometers, 124;
hot springs of, 143;
igneous intrusions, 228, 230, 232-3, 234;
influence of, on human history, 10, 236-45, xv, 136, 137-8;
lightning dangers, i, 156;
making of in various eras, iii, 187-91, 205-6, 213-14, 218-19, 224-6;
metamorphism in, xiv, 234;
old and young, 235-6;
ores and mines, 234, 237-8;
peoples of, 245, xv, 129-31;
plants and animals of, xiii, 321, 381, xiv, 365-6, 370, 376-7;
rainfall and, i, 111, xiv, 354-5;
rime on, i, 121-2;
rock weathering on, iii, 23, 24, xiv, 40, 233-4;
ruggedness due to erosion, 234;
St. Elmo's Fire, i, 157;
shadows in sky, 169-70;
snow-line on, iv, 183-4;
solar radiation on, i, 210;
sound intensity on, 186;
structural topography of, xiv, 94;
stunted trees, xiii, 367;
temperature on high, i, 19;
volcanic, iii, 139, xiv, 225-6, 327
(see also Volcanic Cones);
weighing of, ii, 68-9;
wind types, i, 132-3
Mountain Sickness, i, 328, ii, 144, 150
Mountain Streams, harnessing of, v, 79-81;
material transported by, xiv, 52, 233-4
Mountain Systems, xiv, 227
Mount Wilson Observatory, ii, 147-8;
program and equipment, 152-61
Mouse-hunter (weasel), xii, 349
Mousterian Implements, xv, 100, 105, 107-8
Mouth, cavity as resonance chamber, iv, 232;
dryness of, in fear, ix, 166;
germs in, x, 201, 202, 219, 289;
grasping organ, ix, 82;
opening of, in concussions, xi, 101;
"watering" of, cause, ix, 165

Movement, perceptions of, xi, 165, 166, 170-1, 184, 185

(see also Motion)

Moving Bodies, deflection by earth's rotation, i, 124-5, xiv, 32, 348;
old theory of, ii, 63
Moving Pictures, iv, 347-9;
business men and, xi, 340;
color reproduction in, iv, 369;
facial expressions in, xv, 63;
of eclipses, ii, 212
Moving Picture Machines, v, 329-31;
mercury arc rectifiers in, vi, 333
Moving Star Clusters, ii, 341-4, 379
Mozambique Channel, xiv, 273
Mudfish, xii, 152
Mud Hens, xii, 262
Mud Puppy, xii, 171
Mufflers, automobile, v, 165
Mulberry Tree, fruit, xiii, 55, 226;
paper from, v, 290
Mule Killers, xii, 167
Mullein, hairy covering, xiii, 105
Müller, Johann (1801-58), x, 117-18;
pupils of, 118, 127, 128, 131
Müller, Johann, ii, 13 (see Regiomontanus)
Multiple Proportions, law of, viii, 110

Multiplex Telegraphy, vi, 87, vii, 112-18, 373

Mummies, Egyptian, linen wrappings of, xv, 243;
scars of tuberculosis in, x, 290;
wheat grains found with, ix, 17, xiii, 211
Muriatic Acid, viii, 87
Murrayville Well, iii, 355
Muscle-and-Joint Sense, ix, 80, 90-1, 153
Muscle Cells, ix, 74-5;
action of, 78-9;
fatigue in, 81;
number unchanging, 48, 348
Muscles, action of, ix, 77-9;
action in posture, 83-4;
adrenalin effects, 171, xi, 273;
at birth, ix, 348;
blood supply, how controlled, 216-17, 220;
blood supply in emotion, xi, 136-7;
cell constitution of, ix, 22 (See Muscle Cells);
communication with sense organs, 19-20, 122, 124, 137, 139, 140;
connection with nervous system, 124-37, xi, 19, 20, 24;
control of, by brain, ix, 139-40, 141, 147, 148 (fig.);
cramps in, 313;
development and overdevelopment, x, 304;
development in embryo, xi, 34, 35;
efficiency of, ix, 296;
energy release and restoration, xi, 24-5;
exercise effects, x, 270, 303;
fatigue in, 247, xi, 271, 273-4, ix, 79-81, 83-4;
fear and anger effects on, 166-7, xi, 132, 133;
flexibility and tensions, effects, 337, 339-40, 371, 372, 374;
flexion strength, 41-2;
flexors and extensors, 54, 166, 262-3, ix, 76-7;
force of, 75;
functions in kinetic system, xi, 60;
fundamental purposes of, ix, 86;
injuries to tissues, 287, 348;
irritability of, x, 87;
mechanical action of, 71-2;
kinaesthetic sensations from, xi, 123-8;
kinds of, ix, 74-5;
metabolism of, measurement in calories, 296, 297;
motion sense in, 90-1;
origin from coelom, xii, 27;
pain in relation to, xi, 118-21;
range of effort, ix, 79;
reciprocal innervation, xi, 86;
responses (see Motor Response);
response to contact & distance sensations, ix, 95, 121, 140;
soreness of, 80-1;
strength and capacity, on what dependent, 75-6, 79;
structure, 75;
thickness and length, 75-6;
uses, different kinds of, 82-4;
wasted in starvation, 297-8

(see also Heart Muscle, Skeletal Muscles, Smooth Muscles)

Muscle (Muscular) Senses, ix, 90-1, xi, 63, 64;
in infants, ix, 350;
organs of, 125

Muscular Motion, electricity from, vi, 16-17, 63-4

Mushrooms, character of, xiii, 43, 70;
origin, 223;
reproductive processes, 163-5
Music, fatigue diminished by, x, 247;
Hawaiian, xv, 315;
light transformed to, v, 332-5;
pitch modulations in, iv, 209;
primitive, xv, 312-15
Musical Chords, xi, 106-8
Musical Insects, xii, 109-10

Musical Instruments, development of, xv, 315-18, 325;
quality differences, iv, 233;
reed mouthpieces, 234-5;
stringed, 222-4;
wind, 231
Musical Scale, iv, 206-9, xi, 105-6;
tones in Indian, xv, 314
Musical Terms, from Italian, xv, 161
Musk, source of, xii, 322;
spread of odor of, iv, 131, xi, 80
Musk Deer, xii, 322
Muskox, xii, 328;
in glacial period, xiv, 376
Muskrats, xii, 289, 290
Mussels, xii, 58-67;
in lakes, xiv, 211-12
Mustangs, xii, 307
Mustard, effects on stomach, ix, 243-4;
origin, xiii, 265
Mustard Family, xiii, 197
Mustard Gas, viii, 263, 264, x, 187
Mustard Plant, fruit, xiii, 57 (fig.);
leaf, 38
Mustard Seed, xiii, 60

Mutants, Mutation, ix, 342-3, xiii, 333-4, xv, 23-4, xvi, 155

Mutilations, of body, xv, 257-60;
regeneration of, xii, 170
Muybridge, Edward, v, 330
Myer, Gen. Albert J., i, 217, 220
Myopia, ix, 112
Myotomes, xi, 34, 35
Myrtles, antiquity, xiii, 324-5
Mythology, beginnings of, xv, 357-8
Myxedema, x, 272, 349-50, 351
Nacre, xii, 59
Naias, fertilization, xiii, 151-2
Naids (Naidae) xii, 53-5, 65-6
Nails, former making of, by smiths, iv, 49
Nails (body) cells of, ix, 13
Names, and perceptions, xi, 160-1
Naphthalene, viii, 51, 240, 253
Napier, John, logarithm invention, xvi, 104

Naples, Bay of, crustal movements about, iii, 80-1

Napoleon, dissolution of Salerno University, x, 36;

Egyptian campaign, mirage, i, 172;
indigestion before Waterloo, ix, 238;
Italian campaign, xiv, 244;
military road over Alps, 241;
Russian campaign, i, 306-7;
vaccination order, x, 102-3
Napoleon III, brain weight, xv, 39
Narragansett Bay, oysters of, xii, 61;
scallop fisheries, 65
Narrow-mindedness, muscular causes, xi, 372;
of grinds and thrill-hunters, 376
Narwhales, xii, 297
Nassa, xii, 70
Nassir Eddin, ii, 39
Nasturtium, leaves, xiii, 33 (fig.);
roots, 16 (fig.);
water-dripping by, 108

Natal, forests and grasslands, xiii, 375, 376;
hailstorm, i, 119
Naticas (mollusks), xii, 73
Native Shrubs, advantages, xiii, 273;
planting table, 274-89
Natural Bridges, iii, 127 (fig.), 128
Natural Gas, iii, 354;
composition, viii, 208;
exhaustion of supply, v, 173;
found with petroleum, iii, 350-3, 354, 355;
low luminosity, viii, 60;
origin and occurrence, iii, 354-5;
waste, 355
Natural History School, of medicine, x, 113
Naturalism, development, xvi, 111, 115
Natural Sciences, xvi, 139-48

Natural Selection, x, 135, 136, xv, 23, 24, xvi, 150-1, 152;
disease and, xv, 48;
in man, xv, 47-8;
working of, xii, 293, xiii, 334-5, 346, xv, 24-5

(see also Struggle for Existence, Survival of Fittest)

Nature, actions of, former theories, iv, 18-19, 26;
complexity and interdependence in, xv, 22;
curative powers, of, x, 21, 73, 75-6, 84-5, 367, vii, 240;
cycles in, viii, 349;
efficiency of, vi, 96;
life-renewing instinct, xiii, 116-17;
Longfellow's lines, xvi, 43;
man and, contrasted by language, xi, 224;
personification of, xv, 357;
prodigality (see Prodigality of Nature);
savage attitude toward, xv, 321, 329, 331, 339;
science and the forces of, vii, 235
Nature-Philosophy School, x, 113
Naunyn, Bernard, xvi, 184
Nausea, ix, 91;
cause of, xi, 39;
visceral sense, 63
Nautical Almanacs, ii, 13, 40, 216, 263;
of Greenwich, xvi, 125
Nautilus, pearly, iii, 273-5, xii, 75-6
"Nautilus," submarine, v, 198
Navajo Indians, weaving of, xv, 247 (fig.)
Naval Architecture, problems of, v, 194
Naval Warfare, projectiles in, v, 373
Navigation, chronometers in former, v, 66;
historical development, 182, 188-9, xv, 261-5;
meteorology in, i, 271-83;
wireless applications, vii, 284-5
Neanderthal Cave, xv, 95 (fig.)
Neanderthal Man, xv, 96-8;
disappearance of, 99;
implements of, 107, 108;
period of, iii, 302, xv, 102;
skull of, iii, 304 (fig.)
Neap Tides, ii, 70, xiv, 292
Nearsightedness, ix, 112, xi, 85

Nebraska, potash supplies, viii, 279, xiv, 67;
volcanic ash deposits, 327;
water beneath, iii, 114
Nebulæ, ii, 357-60;
distribution, 352;
double, 377;
Herschel's conception, 16, 368-9;
in connection with new stars, 332, 333;
in relation to Galaxy, 355, 364-5;
in relation to stars, 308-9, 365, 381;
motions, 364;
photographic study, 135-7;
spectra, 116;
types, ring and spiral, iii, 160-1
(see also Spiral Nebulæ)

Nebular Hypothesis, ii, 367-72, 374-5, 380, iii, 159-61;
anticipated by Swedenborg, ii, 367;
applied to asteroids, 258;
in relation to earth's heat, iii, 108, 178, 184-5

Nebulium, ii, 359
Neck, arteries of, ix, 196-7;
pulse in, 311
Necropsies, x, 98
Nectar, of flowers, xiii, 124, 125
Needles, primitive, xv, 81;
threading of, ix, 118
Negative, electrical meaning, vi, 57, 124

Negative Electricity, i, 141, 142, iv, 258, 265, vi, 287, 288;
electrons as, viii, 187-8;
in atmosphere, i, 143
Negroes, color of skin, xv, 36;
hair of, 38;
in Tropics, xiv, 356;
in U. S., 218-19;
language of, xv, 159;
nose index and nostril shape, 46;
prepotency in crosses, x, 230;
susceptibility to lung diseases, xv, 50;
type characteristics, 35
(see also Black Race)

Negroes (African), belief in Reincarnation, xv, 334;
idea of soul, 330;
ideas of sleep, 332;
priests of, 350-1
Nematodes, xii, 45

Neodymium, atomic weight and symbol, viii, 383

Neolithic Period, domestic animals of, xii, 346;
implements of, iii, 302, 306, v, 14, xv, 103, 109-10

Neon, in atmosphere, i, 11, 12;
production and use, i, 33;
symbol and atomic weight, viii, 383
Neotomy, xii, 173
Nephoscope, i, 86, 377
Neptune (planet), ii, 268-9;
atmosphere, 250;
comet families, 271;
discovery, 67, 79, 86, 189, 268, 272;
distance from sun, iii, 159;
habitability, ii, 250;
orbit, 270, 163;
photographic study, 133;
planets beyond, 270-3;
retrograding motion, 271;
size, 163;
rotation period, 377;
weight, 77

Nerve Cells, functions and structure, ix, 122-4, 125;
growth of, 48;
of brain, 140

(see also Connective, Motor and Sensory Nerve Cells)

Nerve Centers, of brain stem, ix, 168, 257
Nerves, color effects, vi, 274-5;
at birth, ix, 348-9;
composition and color, 124, 159-60, xi, 17;
cranial, 29-31 (see Cranial Nerves), ix, 131, 132;
distribution to muscles, 124-5, 127;
electrical excitation, vi, 63-4;
spinal, ix, 131-2, xi, 25-6;
to glands and smooth muscles, ix, 159-60, 162, 164-5

(see also Nerve Cells, Neurones)
Nerve Trunks, ix, 131-2
Nervous Actions, complex, ix, 139-54;
simple, 132-7;
special, 155-72

Nervous Activity, fundamental laws, xi, 18-23, 27-8

Nervous Diseases, electrical treatment, vi, 17, 63-4, 284-5;
electrical treatment, vii, 235, 238-9;
habit in, xi, 248;
hot baths in, x, 311;
physical attendants, 353;
physical causes, xi, 370-2;
suppressed emotions and, 140
Nervous Fatigue, ix, 137-8
Nervous Fluid Theory, x, 85-6
Nervous Prostration, x, 248
Nervous System, xi, 16-32, ix, 122-38;
brain connections in, ix, 142-4, 147-51;
complexity and mental activity, xi, 13, 20;
control of body functions by, x, 346-7, 352-3;
control of glands and smooth muscles by, ix, 159-60, 162-3, 164-5, 168;
development in embryo, 343, 344, 348-9, xi, 34-6;
emergency effects on, ix, 166-7, 171;
examination methods, x, 371;
fatigue effects, xi, 272, 274;
function (Crile), 58;
functional unit, 20;
habit in, 248;
hereditary diseases of, x, 234;
in sleep, xi, 286-8;
part of, in maintaining life, ix, 20, 21, 23;
reciprocal innervation in, xi, 86;
sympathetic, x, 352-3, xi, 134-5;
thyroid effects on, ix, 303, 304
(see also Central Nervous System)
Net Goods, v, 277
Netherlands, delta formation of, xiv, 186
Nettle, hairs of, xiii, 42

Net-veined Leaves, xiii, 32, 34, 176, 178, 183 (fig.);
classification of plants with, 60-1
Networks, electric, vii, 27, 373
Neuralgia, barometric effects, i, 329

Neurasthenic Abscess, Amatus' cure of, x, 58-9

Neurones, xi, 17-18, 20-1, 22
(see also Nerve Cells)
Neurotomes, xi, 34, 35
Neutral Coasts, xiv, 248, 254, 263-4
Nevada, mining products, iii, 366, 368, 370;
"pogonip" fogs, i, 96;
rainfall, 112;
silver mines, viii, 198;
topography, xiv, 42
Névé, granulated snow, iii, 59
New Brunswick, N. J., radio plant, vii, 274-5
Newcomen's Engine, v, 144, xvi, 125

New England, agriculture and manufacturing in, xv, 132;
building stones, iii, 371, 372;
clock making, v, 50;
cod fisheries, xii, 164;
cotton mills, xiii, 236;
"dark days", i, 56-7;
forest trees of, xiv, 372;
geological history, iii, 219, 231-2, 234, 235, 240;
glacial bowlders, 70, xiv, 59;
glacial soil of, 70;
glacial topography, 56, 60;
gorges, iii, 44;
igneous rock formations, xiv, 111, 112;
January thaws, i, 363, 376;
Labrador current effects, xiv, 305;
lakes of, 200;
mussels on coast, xii, 65;
opossums in, 275;
peneplain of southern, iii, 35;
plateau of southern, xiv, 216-17, 221, 236;
"Vineland" as, 261;
water power and manufactures, 31

Newfoundland Banks, cod fisheries of, xii, 164;
fogs, i, 93-4, 94, xiv, 305
(see also Grand Banks)
New Guinea, animals of, xii, 249, 272, 279;
bird of paradise of, xv, 275;
cockatoo of, v, 9-10;
continental island, xiv, 276;
rain forests of, 369
New Jersey, coast of, xiv, 256, 262, 263;
coast destruction, 45, 302;
coastal plain water supply, 138;
dunes on coast, iii, 71;
former copper mines, xiv, 112;
former volcanoes, 318;
igneous rock formations in, 107, 111, 112;
pine barrens, xiii, 371;
silk industry of, xiv, 269;
streams of southern, 160;
zinc production, iii, 363, 364
New Madrid Earthquake, iii, 95, 98
Newman, Cardinal, on change, xiii, 325-6, 336
New Mexico, arid topography of, xiv, 42;
mesas of, 82;
volcanic fields of, 102, 315, 317, 318;
wife auctioning by Indians, xv, 283-4

"New Mexico" (battleship), electrical operation, vii, 327-8;
induction motors, vi, 248
New Orleans, acquisition of, xiv, 193;
founding of, 192;
growth, 219;
harbor of, 270;
yellow fever epidemic, x, 160
New Orleans Inner Harbor Canal, v, 259

Newspapers, printing and presses, v, 301-5, 306;
typesetting by machine, 307-8
Newsprint, making of, v, 292, 298
New Stars (see Novae)

New Testament, sounding lines mentioned in, xiv, 284

Newton, Sir Isaac, ii, 14, 62, iv, 19-20;
forerunners of, ii, 58-9;
gravitation discovery and laws, 63-72, iv, 20, 95-8, xvi, 115-16;

Halley and, ii, 88;
influence of, on mechanics, iv, 11;
laws of motion, ii, 62-3 (see Newton's Laws);
light experiments, ii, 111, iv, 357, xvi, 119;
light theory of, iv, 47;
mathematical work, ii, 14-15, xvi, 115-16;
methods, ii, 71;
on comets, 85;
on conservation of energy, xvi, 131;
on mountain observatories, ii, 139, 140;
on precession, 70-1;
on refracting telescopes, 100, 140;
on shape of earth, 69;
on tides, 70;
on time, iv, 15;
on what gravitation is, ii, 78;
"Principia", 13, 63, 67-8, 88, xvi, 105, 115;
sound velocity law, iv, 198;
telescopes, ii, 102, 103

Newton's Laws of Motion, ii, 62-3, 66, iv, 61-9;
anticipated by Galileo, ii, 56, iv, 19;
applicability, 86;
based on absolute space and time, 16, 18;
discovered under apple tree, v, 109
Newts, xii, 169, 170-3
New Vienna School, x, 113
New York (City), Beach's subway, v, 138;
Broadway lighting, vii, 340-1;
croton bugs of, xii, 107;
Croton Dam, iv, 119;
crowds after Lincoln's death, xi, 323;
Edison system, vi, 151, xvi, 188;
five-cent fare, vii, 198;
garbage value, viii, 330;
geological changes around, iii, 78, 79;
growth, to what due, xiv, 267-8;
"hobble-skirt" cars, vii, 184;
insects around, xii, 99;
magnetism of earth at, iv, 247, 249, 250, 252;

Penn. R. R. station, xiv, 146;
region west of, iii, 211 (fig.);
sewage disposal, viii, 325;
submachine guns for police, v, 368;
subway excavating, 261;
subways, air-brake system, 132-3;
subways, dust, i, 325;
subways, electrolytic corrosion, vi, 66;
synchronized electric service, 384;
telephone connections with Los Angeles, 367-8;
telephone exchanges, vii, 103;
telephones in, 75;
telephones, automatic, vi, 87, vii, 92, 106;
temperature range, xiv, 346;
terminals electrified, vi, 162, vii, 181-2, 193-4;
underground wire systems, 12, 14, 24;
water supply, viii, 317, xiv, 140;
weathering in climate of, iii, 23;
wireless device in Times Square, vii, 280

New York Harbor, developing shore lines, iii, 58;
dredging of Ambrose Channel, v, 257-8;
formation of, xiv, 255, 268;
lighterage conditions, 266-7;
sedimentary deposits, 268-9;
wireless piloting, vii, 284-5
New York (State), drumlins, iii, 69, xiv, 60;
finger lakes, 203, 211;
forest trees of, 372;
geological history, iii, 195-6, 231-2, 234-5, 219, 240, 243-5;
glacial bowlders, 70;
glacial soil of, xiv, 70;
glacial topography, 56, 60, 61;
gorges, iii, 44, 243, xiv, 50, 52, 171-2, xiv, 50, 52, 171-2;
gypsum deposits, iii, 376;
lakes, how formed, 143-4, 145;
lakes, number, xiv, 200;
oyster industry, xii, 61;
salt deposits, iii, 375, viii, 140;
weather observations, organized, i, 215
New Zealand, coasts, xiv, 258, 264;
geological history, 275-6;
Maori of (see Maori);
native carvings in, xv, 300;
ratite birds of, xii, 249;
sheep plant, xiii, 379;
sheep-raising in, xiv, 384;
snakes absent from, xii, 217;
spinach in, xiii, 224;
travertine terraces, xiv, 146;
tuatera of, xii, 183-4

Niagara Falls, electric furnace industries at, vii, 302;
harnessing of, vi, 368-70;
origin and history, iii, 45-7, 243;
rate of recession, 246;
verticality due to undermining, xiv, 133;
working power, vi, 47
Niagara Falls Power Plant, vi, 368-78;
load factor and charges, 381;
phased with Canadian plant, 384
Niagara Limestone, iii, 192
Niagara River, drop in, vi, 368;
due to Ice Age, iii, 243;
first impressiveness, vii, 202;
gorge of, xiv, 51
"Niagaras," Electric, i, 342, 343-4
Nickel, viii, 126-7, 154;
affinity strength, 128;
atomic weight and symbol, 383;
classification place, 178, 183;
electrical conductivity, iv, 283, vi, 77;
fusibility, viii, 384;
in earth's interior, xiv, 11;
in steel alloys, xiv, 238;
magnetic susceptibility, iv, 251;
melting point and requirements, iv, 162;
ores of, viii, 198, 270;
positiveness, vi, 59;
source, xiv, 238;
test for, viii, 287, 289
Nickel-Iron Batteries, vi, 149-51
Nickel Plating, vii, 314, 316-17
Nicol's Prism, iv, 354
Nieve Penitente, i, 117, 377
Niger River, furrow of, xiv, 287;
Park's explorations, xvi, 123
Night, cooling of earth at, i, 121;
"falling" of, xi, 173;
plant conduct at, xiii, 88-9, 113, 114, 126
Night Adders, xii, 232

Night-Blooming Plants, fertilization, xiii, 152-3

Nightingales, xii, 269
Nightjar Family, xii, 267
Nightshade, xiii, 250
Nile River, aerial photography, i, 46-7;
ancient harnessing, v, 19;
annual overflow of, xiv, 53, 70-1;
bichir of, xii, 151;
Bruce's exploration, xvi, 123;
connections with Congo system, xiv, 186-7;
course of, 120, 155;
crocodiles of, xii, 199;
dominance of Egyptian life, ii, 26;
Egypt gift of, xiv, 71;
gobar of upper region, i, 96;
hippopotamus of, xii, 310;
length and volume, xiv, 189;
rafts used on, xv, 264-5;
veneration in Egypt, v, 18;
water supply of, xiv, 182-3
Nile Valley, antiquity of man in, xv, 84;
fertility, xiv, 71;
sand-abrasion of granite bluffs, 77
Nimbus Clouds, i, 98, 101, 103, 377
Ninevah, burying of, iii, 75
Ninevah Eclipse, ii, 209
Nipissing Lakes, iii, 150, 151
Nirvana, xv, 334
Niton, viii, 185;
atomic weight and symbol, 383;
in atmosphere, i, 11, 12
Nitrate Group, viii, 93;
in explosives, 71
Nitrates, cellulose forms, viii, 254-5;
Chilian deposits, i, 35;
viii, 64, 197, xiv, 66;
commercial production, i, 35-6, vii, 322, 323-4, viii, 74;
formation in soil, i, 35, viii, 340, 345, xiii, 98;
metal occurrence in, viii, 130;
test, 290;
uses, 72;
arterial spasm, x, 381
(see also Potassium, Silver, Sodium Nitrates)

Nitric Acid, character and uses, viii, 71-3, 115, 116;
in atmosphere, i, 13;
production of, 36, vii, 322, 323-4, viii, 74, 137, 275;
solubility, 112;
strength, 115
Nitro, defined, viii, 379
Nitrocellulose, viii, 255, 256, 261
Nitro Compounds, viii, 237;
in explosives, 71
Nitrogen, viii, 18, 64-8;
agricultural needs and sources, i, 34, vii, 321, viii, 73-4, 75, 280, 340, 341, 343, 345-6, xiv, 64-5, 66;
atmospheric, i, 10, 11, 34, vii, 321-2, viii, 67;
atomic weight and symbol, 383;
boiling and freezing points, iv, 173;
chemical inertness, i, 12-13;
critical temperature, 29, iv, 173;
derivatives, viii, 229-30
(see also Amines);
elimination from body, 353-4, x, 342;
fixation, natural and artificial, i, 13, 33, 34-7, 153, vii, 301, 321-4, 352-3, viii, 66, 73-5, 153, 345-6, x, 193-4, xiii, 98, xiv, 66, xvi, 165;
freed by combustion and decay, viii, 61, 330, 345-6;
in blood effects, i, 329, v, 120, x, 346;
in chlorophyll, xiii, 80;
in explosives, viii, 63, 345-6;
in garbage, 330;
in proteins, 64-5, 340, 351, ix, 29, 279, 282, 284, x, 270, 277;
industrial uses, i, 33, 34;
liquefaction of, iv, 171;
melting point, 162;
preparation from air, viii, 65-6;
production from liquid air, i, 30, 32, 34, viii, 67, 68, 274;
solubility in water, 40, 111;
spectrum of, i, 161
Nitrogen Compounds, viii, 64, 68-74;
by-products of coke, 46-7;
in air, i, 13;
in animal body, viii, 353-4;
instability, 66;
organic, 229-30;
vitamines, 369
Nitrogen Cycle, viii, 73, 334, 335, 349;
practical applications, 325-6, 330, 340, 345-6

Nitrogenous Waste, x, 270
Nitroglycerine, viii, 63, 247-8, 260, 261
Nitrous Acid, viii, 115;
in atmosphere, i, 13;
production, 36
Nitrous Oxide, viii, 70-1;
as anesthetic, x, 123-4;
critical temperature and pressure, iv, 172
Nobody Crabs, xii, 89
Noctilucent Clouds, i, 17-18, 58, 377
Nodes, of moon, ii, 197
Nodes, of vibrations, iv, 217
Noguchi, Hideyo, x, 173
Noises, awe roused by, xi, 147;
qualities of, 104
Nomadic Life, xv, 128, xiv, 141

Nonconductors, (electrical) iv, 259, vi, 77, 294, vii, 373;
nonmetals as, viii, 126
Nonmetals, viii, 17-19, 84, 126, 379;
in body tissues, 354;
manufacture and uses, 274-5;
negative ionization, 122;
oxides of, 20, 39;
periodic classification, 181;
plants needs of, 337, 341;
tests, 289-90;
union with metals, 20, 32
Nordic Group, xvi, 48-9, 50
Norfolk, Va., harbor of, xiv, 268
Noria, ancient use of, v, 19
Normals, meteorological, i, 204, 378
North Africa, civet cat of, vii, 353;
civilization in, xiv, 196;
mormoids of, xii, 154;
vultures of, 260;
zoölogy of, xiv, 291
North America, ancient camels of, xii, 313;
animals (carnivora), 340, 342-3, 349;
birds of, 268-9;
climate of eastern, xiv, 346-7;
climate on opposite coasts, 345;
coasts, Atlantic and Pacific, 25-6, 40, 247-8, 249-50;
cyclones and tornadoes, i, 137;
drainage systems, xiv, 190;
exploration and settlement, 196-7, 310-11;
forests of, 371, 372-4, 375-6;
former connection with Asia, xii, 313, xiii, 351, xiv, 30;
former connection with Europe, 290;
frogs of, xii, 180;
fur animals of, 350;
geological history, iii, 164-248;

Ice Age and resulting topography, 62, 236-48, xiv, 3, 30, 43, 59-62, 200, xv, 74-6;
indigenous plants, xiv, 382;
no absolute deserts in, xiii, 377;
Northmen in, xiv, 261;
rainfall of, 360;
rivers in history, 31, 190-5, 196-7;
snails of, xii, 69, 71;
tobacco used by natives, xiii, 256;
trees of, xiv, 375-7;
Urodela of, xii, 170-2
North American Basin, xiv, 288-9

North Atlantic Ocean, birds of, xii, 251, 252, 253;
currents of, xiv, 304;
deep sea life in, xii, 23;
formation of, xiv, 290;
giant squids of, xii, 79-80;
herring fisheries, 156;
limacina of, 19;
sharks of, 145, 146;
temperature of, xiv, 297;
walruses of, xii, 334;
weather charts, i, 275, 276
North Beach, Florida, wave power at, xiv, 300
North Cape, level changes at, xiv, 34

North Carolina, Appalachian Mts. in, xiv, 97, 168;
coast of, 264;
thermal belts, i, 259;
trap dikes of, xiv, 112-13

Northern Hemisphere, cradle of flowering plants, xiii, 319;
deflection of motion in, i, 125;
dip of magnetic needle in, iv, 245-6;
forests of, xiv, 371;
land in, 20;
winds of, i, 125, 127, 128, 137, xiv, 345-6, 348

Northern Lights, i, 158 (see Aurora)
Northmen, history of, xiv, 261-2
North Pole, rain at, i, 109
North Sea, commerce development in, xiv, 308;
formation of, 287;
formerly land, xv, 76;
herring fisheries, xii, 156
Norway, barley ripening in, xiv, 365;
civilization of, xv, 131;
coasts, iii, 57, 79;
coasts, xiv, 247, 258, 259
(see also Fjords);
glaciers of, 55;
Gulf Stream effects, 304;
latitude of, 315;
nitrogen fixation, i, 36, vii, 324, viii, 74;
plain on west coast, xiv, 47
Nose, adaptation to odors, xi, 80;
bones of, ix, 62;
cartilage in, 57;
cleanings of, x, 312;
cold effects on, ix, 311;
functions and diseases of, x, 341;
germ infection through, 198, 202, 219;
in infants, xv, 61;
nerve connections, xi, 81-2;
organ of smell, 62, 78;
passages, 77;
plastic surgery of, x, 57, 189;
racial types, xv, 45-6;
smell organs in, ix, 96;
violent blowing, danger, xi, 101;
X-ray examinations of, x, 373
Nose Rings, xv, 259 (fig.), 260
Nostrils, of monkeys, xii, 376;
racial shapes of, xv, 46
Notes, musical, iv, 206-9, xi, 105-6;
of Indian scale, xv, 311;
pitch and intervals, iv, 205-6, ix, 99-100;
pitch changes by motion, iv, 210;
quality of, to what due, 233
Notochord, xii, 128;
in lancelets, 129
Novae, or New Stars, ii, 331-3;
explanation, 329;
in class of variables, 324;
location, 328;
outbursts, 328-9
Nova Scotia, coal beds, iii, 199;
Vineland as, xiv, 261
Nuclei, chemical, xvi, 162
Nuggets, iii, 367

Numbers, development of systems of, xv, 180-4;

Pythagorean theory, xvi, 80
Numerals, Arabic, xvi, 103;
Babylonian, 60-1
Nummulites, iii, 235
Nut Butter, source, xiii, 10, 220
Nuthatches, xii, 268
Nutmeg, xiii, 261-2
Nutrition, chemistry of, viii, 348-72;
defective, due to under-chewing, ix, 228;
deficiency of, disease from, x, 255-68, 314;
problem of, in therapy, 382;
stimulated by light, 253
(see also Diet, Food)
Nuts, food value, viii, 366;
oil in, 246
Nymphs (aquatic larvæ), xii, 106
Oak-Hazel Copses, xiii, 369-70
Oak Trees, antiquity, xiii, 324-5;
family, 193;
fertilization, 148;
flowers without petals, 190;
index plants, i, 255;
in American forests, xiv, 373;
in Danish Peat bogs, xv, 87;
in landscaping, xiii, 271-2;
northern limit, 367;
rate of increase of, xv, 19, 21
Oaths, judicial, xv, 373-4
Oats, food value, viii, 364;
native of Old World, xiii, 182;
vitamines in, x, 262
Obelisks, Egyptian, ii, 24
Obesity, x, 272-5
Obsequent Streams, xiv, 160, 174
Observatories, ancient, ii, 37, 38, 39;
mountain, 139-51;
first European, xvi, 100
Occupational Diseases, x, 244-6
Occupational Fatigue, xi, 270
Occupational Postures, xi, 371, 372

Ocean, Oceans, annual discharge of rivers into, xiv, 135;
atmospheric conditions over, i, 13, 14, 143-4, vii, 212;
basins and shoal water line, xiv, 24-6, 287-8;
basins, topographical features, iii, 52, xiv, 27, 286-90;
birds of, xii, 251-4, 258, 264;
chemical elements in, xiii, 196-7;
circulation of water in, xiv, 298-9, 303-5;
color of, viii, 40;
coloring, to what due, xii, 17, xvi, 147;
density of water in, v, 195-6, xii, 21-2;
deposits on floor, iii, 52-5, 168, xiv, 284-6;
depths, iii, 51, xii, 21, xiii, 72, xiv, 23-4, 26-7, 288-9, 290

(see also Deep Sea);
depths still a mystery, v, 202;
divisions, xiv, 22;
earthquakes in, 336-7;
erosive work (see Ocean Waves);
evaporation, vii, 212;
exploration of, xiv, 283-4;
extent of distribution, 20-3, iii, 51;
faulting in bed of, xiv, 39;
floors, general flatness, iii, 52, xiv, 24, 284;
floor level changes, iii, 83, 168, 206, xiv, 34, 253;
floors never land, iii, 55, xiv, 290;
floor, ooze of, xii, 17-18;
former extensions, iii, 12, 54, 55, 130, 132, 165-224 (maps), 235, xiii, 298-9, xiv, 19;
heating and cooling of, 346;
historical importance, 305-11;
metals found in, viii, 148;
meteorology of, i, 271-83;
organic life of, xii, 16-24, xvi, 146-8;
organic life in relation to salts, ix, 174, 175;
phosphorescence of, xii, 18-20, 84;
potassium compounds in, viii, 143, 279;
power from, v, 174 (see Tides, Ocean Waves);
pressure of water in, v, 95, 201;
salinity, iii, 51-2, viii, 138-9, 195, 196, 279, xiv, 295-6;
salt of early, ix, 175-6;
soundings, xiv, 284;
surface form and tides, 291-5;
temperature layers, xii, 21-2, xiv, 297-9;
theories of origin, iii, 160, 163;
thunder audibility, i, 193;
volcanoes in, xiv, 285-6;
wind and pressure belts, i, 128-9;
wind charts, 271-6
Ocean Commerce, development of, xiv, 305-11
Ocean Currents, xiv, 303-5;
altering courses, i, 345;
charts, 271-6;
deflection by earth's rotation, xiv, 32;
plant and animal distribution by, 277, 278;
seed-dispersal by, xiii, 346-8
Oceanic Islands, xiv, 276-9;
plants of, xiii, 348
Ocean Steamers, development, v, 192-4;
strains on, 194;
turbines in, 153-4
Ocean Waves, base level of erosion, xiv, 254;
cause, 299;
coast destruction by, iii, 55-7, xiv, 44, 45, 46, 299-303;
length, vi, 269;
motion, v, 124;
power uses, 174;
quelled by compressed air, 124-5
Ocelots, xii, 364
Octopus, xii, 77
Odorous Oils, in mint plants, xiii, 205
Odors, ix, 97;
adaptation to, 97, xi, 80-1;
agreeable, enjoyment of, ix, 98;
classification, xi, 79;
digestion and, x, 320;
inhibition effects, xi, 81;
perception of, ix, 96, 97;
spread of, iv, 131
Odyssey, historic value of, xv, 323-4
Oersted, Hans Christian, vi, 19-20;
electromagnetic discovery, iv, 276;
on waterspouts, i, 356
Ogden River Canyon, iii, 39;
thrust faults in, 92
Ohm, Dr. S. G., vi, 21-2
Ohm's Law, iv, 281-2, vi, 22, 74-5, vii, 373;
applied in meter construction, 157-8;
anticipated by Cavendish, vi, 17;
for alternating currents, 164-5, 169-70
Ohmmeter, vi, 80

Ohms, electrical resistance unit, iv, 282, 284, vi, 71, 74-5, 170, 171, vii, 373;
method of measuring, 165-6 (see Ohm's Law)
Ohio, corn-crops and weather, i, 245-8;
glacial drift in, xiv, 170
Ohio River, drainage changes, iii, 245;
water supply and sewage, viii, 318
Ohio Valley, floods, i, 110-11
Oil, fuel on battleships, vii, 328;

Crude (see Petroleum), films of, colors in, iv, 377;
shark's, xii, 146-7;
turtle, 194;
use in lessening friction, v, 203
Oildag, vii, 300
Oil of Vitriol, iii, 336, viii, 83
Oil Pools, iii, 380
Oils, defined, viii, 244
Oils, Fatty, viii, 244, 245, 246, 247;
as food, 363;
hydrogenation of, 232, 247;
insolubility, 112;
preserving of, 371;
vegetable (see Vegetable Oils)
Oil Wells, drilling of, v, 265-7;
from diatom deposits, ix, 28;
gushers, iii, 353-4;
productiveness and life of, 353
Okapi, xii, 321-2
Okeechobee, Lake, xiv, 200
Old Age, cause of degeneration in, x, 201;
feelings of time in, xi, 194;
jaws in, ix, 57
"Old Probabilities", i, 216-17
Old Testament, hygienic laws in, x, 15;
morality of, xv, 374
Old Vienna School, x, 77, 104
Old Wives' Remedies, xiii, 249
Oleic Acid, viii, 221
Olfactory Nerve, ix, 142, xi, 29-30, 81-2
Oligoclase, iii, 329
Olive Oil, chemical nature, viii, 231;
making of, by plants, ix, 28, xiii, 95;
substitutes for, viii, 363
Olives, acquired taste for, xi, 72, 73;
origin, xiii, 226
Olivine, iii, 334
Omega Centauri, ii, 136, 336-7, 338-9
Omens, belief in, xv, 355

Omicron Ceti, type of variables, ii, 324-5, 327

Onions, antiscurvy vitamines in, x, 266;
bulb, xiii, 25 (fig.);
in lily family, 184;
origin, 223;
underground, stems, 23
Ontario, glacial soil of, xiv, 70, 170;
Keewatin series, iii, 169;
lakes, 143;
oldest fossils in, 250
Ontario, Lake, increasing altitude, iii, 82

Oozes, deep-sea, iii, 54, xii, 18, 19, xiv, 285

Opals, iii, 334-5
Opaque Bodies, iv, 324;
X-ray examination, vii, 253-5
Open Hearth Furnaces, v, 320-2, 323
Open-Hearth Process, viii, 160, 269
Opium, history and sources, xiii, 253-4;
use of, in tropics, xv, 126-7
Oppolzer, Johannes von, x, 113
Opossums, xii, 274-6, 278;
embryological resemblances, xv, 54;
instinct of, xi, 46
Optical Illusions, iv, 323, xi, 184-90;
due to atmospheric refractions, i, 171-4, iv, 326-9

Optic Nerve, ix, 110 (fig.), 124, 142, xi, 29-30, 84-5;
discovery, xvi, 82;
retina and, iv, 346;
stimuli affecting, x, 118
Optics, atmospheric, i, 164-85;
"father of physiologic", x, 97;
history of development, xvi, 101, 119
Optimal Temperature, xi, 51
Optophone, v, 332-5, 384

Orange (color), complementary color of, iv, 367;
heat color, 361;
soothing effects, vi, 274, 275
Orange Juice, for babies, ix, 347
Oranges, food values, x, 266, 268;
origin, xiii, 226;
spread, 354;
true berries, 54
Orang-utan, xii, 381, 383;
compared with man, xv, 59;
of Bronx Garden, v, 9
Orators, advantages over writers, xv, 145;
limited speeches of ancient, v, 62;
pitch of voice of, iv, 232
Orchards, frost protection, i, 259, 332;
warm and cold spots, 258-9
Orchestras, sounds of, iv, 199
Orchid Family, xiii, 184-7
Orchids, aerial roots, xiii, 20-1;
butterfly, 145;
epiphytic, 362;
fertilization, 144-5;
flowers, 50;
highest of monocotyledons, 181;
illustrations, 145-7;
leaves of saprophytic, 100;
Madagascar, 48;
seeds, 154, 344;
vanilla, 259-60;
in tropical forests, xiv, 368
Ordeals, xv, 373
Ordovician Period, iii, 20, 185-91, 381;
plants and animals, 251, 261, 266, 267, 268, 270, 273, 274, 277, 281;
sea extensions in, 183 (fig.)
Ore Deposits, iii, 355-70, viii, 197-200
Oregon, block mountains, iii, 139;
earthquakes in, xiv, 331;
forests of, 374;
lava formations, 102, 104, 318;
storm waves on coast, 300
Ores, defined, iii, 381, viii, 197;
electrolytic refining, vii, 319-21;
extraction of metals from, viii, 131, 269-72;
in metamorphic rocks, xiv, 234, 237;
veins, how formed, iii, 126
Oresme, Nicole, xvi, 101
Organic, defined, viii, 380
Organic Acids, viii, 52, 219-21, 336
Organic Chemical Industries, viii, 241-66
Organic Chemistry, viii, 52, 204-40;
beginnings, xvi, 162
Organic Compounds, viii, 51-2, 204, 205;
character of series, 207;
colors, 85-6, 258, 312;
explosion of, 63;
interchange of groups, 211;
physical state and molecular complexity, 298;
solubility in water, 37
Organic Life, beauty universal, xvi, 145-6;
climatic influences, 141-2;
distinction from inorganic realm, xii, 13-14;
origin, xiii, 300-1, xvi, 144-5, 149;
no traces in meteors, ii, 292;
studies of Mayer and Helmholtz, xvi, 142
(see also Life)
Organic Liquids, solubility, viii, 112

Organic Matter, chemical constituents, viii, 18, 29, 34, 42, 64;
food of animals, 349;
formed by plants, xiii, 14;
in atmospheric dust, i, 60-1;
in soils, viii, 339-40;
in waters, 40-1
Organicists, school of, x, 86
Organisms, binomial nomenclature, x, 84;
cell constitution, 119, xv, 16, xvi, 142;
chemical basis of, xii, 10-13;
chemistry of, viii, 204-5, 348-72;
chemosynthetic, xii, 15;
earliest, xiii, 299, 303;
frames and shells, xvi, 145;
growth and forms due to physical laws, xvi, 142, 144-5;
growth compared with crystallization, iii, 311;
metals congenial to, viii, 148;
microscopic (see Germs);
reproduction of, x, 228;
symmetry in, xvi, 155;
variations, meristic and substantive, xvi, 155;
vestiges in oldest rocks, iii, 249-50 (see Animals, Plants)

Organogens, viii, 18

Organs (physical), disordered functions of, x, 318-65;
vital function testing, 376-9, 382-3
Organs (musical), iv, 228-31;
flue and reed styles, 234-5;
intervals on, 208;
temperature effects on, 231-2;
pipes of, xv, 316
Oribasius, x, 31
Oriental Gobies, fins of, xii, 134
Orientation, in ancient temples, ii, 25-6
Orinoco Basin, arrau turtle of, xii, 193-4;
chocolate in, xiii, 234;
jaguars of, xii, 362
Orinoco River, caribes of, xii, 160;
connections with Amazon, xiv, 187
Orioles, xii, 269

Orion, great nebula in, ii, 357, 359, 363, 364;
moving clusters of, 343;
distortions from sun's motion, 306
Orion Stars, ii, 117;
moving clusters among, 343;
radial velocities, 308
Orkney Islands, wave action at Wick, xiv, 300
Ornaments, bodily, xv, 253-4
Ornithorhynchus, xii, 272
Orongo, Mongolian, xii, 327
Orpathology, x, 318
Orräus, of Russia, x, 164
Orris Root, source, xiii, 189
Orthoclase, iii, 328;
hardness of, 320
Orthodontia Appliances, xi, 373
Orthoptera, xii, 107-10
Osborn, Henry Fairfield, quoted, xii, 13
Osborn, Prof., on cave pictures, xv, 115-16;
on Neanderthal Man, 97
Osborne, J. W., i, 319
Oscillation Circuits, vii, 263, 265, 373-4;
theory of, 286-98
Oscillation Generators, vii, 273-8, 290-1

Oscillations, electric, iv, 313, 314, vii, 373-4;
damped and undamped (see Damped, Undamped Waves)

Oscillations, in planetary system, ii, 75
Osler, Sir William, x, 150-2;
on conceptions of disease and therapy, 380;
on Pasteur, 144;
on sleeping sickness, 169;
on yellow fever germ, 162-3;
on hardened arteries, x, 335
Osler's Disease, x, 152
Osler's Spots, x, 152
Osmium, viii, 172;
symbol and atomic weight, 383;
valence, 178, 180
Osmosis, xiii, 91-2, 93-4
Osmotic Pressure, viii, 113, xiii, 93-4;
bursting of fern spores by, 156;
discovery and law, xvi, 164;
in solutions, viii, 123, 311;
water supplied to plants by, xiii, 102
Ostracoderms, iii, 260, 281-2
Ostracods, xii, 18-19
Ostriches, xii, 249;
hunting of, by bushmen, xv, 134-5, 222
Ostrich Fern, xiii, 159
Ostrich Plumes, xii, 244
Ostwald, chemical work, xvi, 164, 165
Ostwald's Imperative, xi, 257
Oswego Tea Plant, xiii, 201, 205
Ottoman Turks, conquests of, xiv, 308-9
Otters, xii, 347
Ouachita Range, xiv, 227
Oughtred, William, xvi, 104
Ounce (leopard), xii, 357
Outcrop, defined, iii, 381
Outdoor Treatment, x, 240-1
Outgoing Reactions, xi, 54-6, 146
Outriggers, xv, 263-4
Outwash Plains, iii, 68-9
Ouzels, xii, 268
Ovaries, of plants, xiii, 46, 54-5, 118;
beginnings, 317-18;
grouping of plants by, 173-5;
superior and inferior, 202-3
Ovariotomy, x, 122, 147
Over-Compound Generators, vi, 189-90
Overeating, auto-intoxication by, xi, 370;
hardened arteries from, x, 335
Overhead Transmission, vii, 10-11, 14-24, 25
(see also Trolley System);
in telephony, 104, 105
Overheated Liquids, viii, 304
Overshot Wheels, v, 76
Overtones, iv, 213;
of organs, 230-1;
quality of sounds due to, 233
Overwork, fatigue from, xi, 269, 272, 371;
muscular soreness from, ix, 81
Ovules, plant, xiii, 118, 119;
action of fertilized, 153;
naked and enclosed, 173-5
Owen, morphology studies, xvi, 140-1
Owens Automobile, vi, 104

Owen's Valley, California, earthquake of, xiv, 334, 335

Owls, xii, 267
Oxalic Acid, viii, 222, 336
Oxbow Streams and Lakes, iii, 34, xiv, 162
Oxford University, foundation, xvi, 100
Oxidation, defined, viii, 380;
in water, 35;
of organic substances, 266;
of sewage, 326, 327;
of iron, v, 316 (see Rusting);
power extraction by, ix, 16, 24
Oxide of Manganese, ancient use of, xv, 113
Oxides, defined, viii, 380;
chemical formation, 11-13, 20, 36;
combinations with water, 38-9;
extraction of metals from, 47, 131, 271;
metallic and nonmetallic, 20;
ores, 47, 198
Oxyacetylene Blowpipe, i, 33
Oxy-acids, viii, 98, 380
Oxyhemoglobin, ix, 259-60
Oxygen, viii, 17, 34-6;
affinities, i, 12, viii, 33, 36, 47, 77, 85, 87, 134, 155;
amount inspired in sleep, xi, 283, 285;
atmospheric, i, 10, 11, 24, 25;
atmospheric, viii, 67;
atomic weight, 33, 39, 383;
atomic weight base, 92;
body needs and supply, ix, 198-9, 253-62, 267-8, x, 338-9;
boiling and freezing points, iv, 173;
carriers of, viii, 71;
carrying of, in blood, ix, 182-3, 258-61, x, 338-9;
combustion and, i, 10, iv, 138, viii, 12-13, 53, 54, 55-6, 61;
consumption by gas lighting, vi, 264;
consumption of, in exercise, ix, 261-2;
corrosion of metals by, viii, 13;
critical temperature, i, 29, iv, 174;
deficiency effects, i, 322, 328, ix, 268, x, 238, xi, 371;
density of, iv, 110;
diffusibility, viii, 108;
discovery, 34, 170, xiv, 65, xvi, 120;
energy source, viii, 268;
elimination from body, 353;
explosion with hydrogen, viii, 62;
hydrocarbon derivatives, 52, 212, 216-20;
importance, i, 24, 25;
in chlorophyll, xiii, 80;
in coal series, iii, 345;
in earth's crust, 308, viii, 19, 129, 192;
in organic compounds, 64, 204;
in proteins, 351;
in steel making, vii, 321;
in water, viii, 39-40, x, 26;
industrial uses, i, 32-3, viii, 274;
liquefied, i, 29, iv, 171, viii, 68;
melting point, iv, 162;
molecular structure, viii, 26-7, 36;
molecular velocity in, iv, 133, viii, 24;
most active form, 36, 41;
negativeness of, 31;
necessity of, to life, ix, 16, 18, 22, 267-8;
plant uses of, viii, 336-7, 340-1, xiii, 14, 80, 81, 109, xiv, 64-5;
potential energy in, iv, 82;
preparation, viii, 34-5;
production by plants, 49, 335, xiii, 81, 82, 109, xiv, 65;
production from liquid air, i, 30, 32-3, viii, 68, 274;
production from nitric acid and nitrates, 72;
production from water, 30, 31, 274;
rock decomposition by, 194, iii, 24, 25;
rusting produced by, 25;
solubility in water, viii, 35, 40, 111;
supply of, in air, ix, 254, 267-8;
symbol, viii, 383;
valences to, 178, 179-80
Oxygen Compounds, viii, 20, 34, 36-41, 70-4
Oxygen Cycle, viii, 334, 350
Oysters, iii, 260, 272, xii, 58-63;
enemies and destroyers, 50, 70, 72, 73;
food procuring by, ix, 19, 74;
raw, digestion of, 233
Oyster-Shells, deposits of, iii, 272
Ozone, i, 15-16, 378, vii, 353-5;
activity of, viii, 36;
allotropic form of oxygen, 43;
electrical production, vii, 238-9, 301;
molecular structure, viii, 26, 36;
production by lightning, i, 153
Pacas, xii, 289

Pacific Coast, geological changes, iii, 213, 222, 214 (maps);
ports and commerce of, xiv, 269;
potash from seaweeds, viii, 279;
seaweed of, xiii, 27, xiv, 67, 68;
shellfish of, xii, 62, 65, 68, 74;
thunderstorms rare, vii, 218;
width of continental shelf, xiv, 285
Pacific Coastal Plain, xiv, 215
Pacific Coast Forest, xiv, 374
Pacific Drainage System, xiv, 189-90
Pacific Islands, xiv, 277;
coco palm of, xv, 125;
weapons of, xv, 216, 219

Pacific Ocean, climate on opposite coasts, xiv, 345;
coral reefs in, 264;
currents of, 304, 305;
depths, iii, 51, xiv, 23;
extent, 22;
herring of, xii, 156;
salmon of, 157;
seals of, 333-4;
sharks of, 145, 146;
shoal-water belt, xiv, 25;
temperatures, 297;
trade winds, i, 127;
unchanged for ages, iii, 55;
volcanic dust in, 55;
whales of, xii, 298
Pacific Type of Coasts, xiv, 247-9, 250
Pack Rats, acquisitiveness of, xii, 292-3
Packing, Maudsley's cup leather, v, 99, 376
Paddle-fish, xii, 151
Paget, Sir James, xvi, 184
Pain, xi, 116-21;
"arrival platform" for, ix, 146;
contact sense of, 91;
expression of, by dogs and monkeys, xv, 64-5;
no space perception by, xi, 164;
organs and nerves in skin, ix, 314;
purpose as warning, 87;
sense of, in infants, 349;
use of morphine in, x, 381
Painter Fogs, i, 96-7, 378

Painting, art of, beginnings and development, xv, 108-9, 110-16, 120-1, 297-303, 325;
by compressed air, i, 29, iv, 130, v, 136;
of body, xv, 255-6
Paintings, depth impressions in, ix, 120;
skies in, i, 105
Paints, ancient, xv, 113-14;
chemistry of, viii, 264-6;
colors of, iv, 369-70;
drying oils in, viii, 245, 247;
lead in, 162;
linseed oil in, 231
Pajero, xii, 364
Paleolithic Man, iii, 303-5;
horses of, xii, 307;
implements of, xv, 103, 105-9;
state of, xiii, 209-10
Paleontology, defined, iii, 381;
history, xvi, 169, 170, 172
Paleophytology, xvi, 167
Paleozoic Era, iii, 20, 381;
animals, 263, 266-75, 276-8, 284, 285, xii, 49, 75, 104, 142, 151, 165;
climatic zones in, iii, 173;
divisions and species of, xv, 71;
plants, iii, 251-5;
rocks and history, 179-207;
vertebrates absent, 261
Paleozoic Rocks, iii, 179-207;
recognizable by fossils, 174, 179;
why rich in fossils, 264

Palestine, ancient rain measurements, i, 68, 213;
climate changes in, xiv, 361-2, 379;
maritime plain of, xv, 138

Palisades of the Hudson, iii, 111, 212, xiv, 108-9, 122;
blocks at foot of, 76;
jointing at Bergen Cut, 133
Palladium, viii, 173;
as catalyzer, 103;
symbol and atomic weight, 383
Pallas, meteor found by, ii, 284
Pallas (asteroid), discovery, ii, 255;
orbit, 258
Pallor, causes of, x, 337;
temporary, ix, 161, 162, 163, 165, 166
Palm Beach, millionaires at, xi, 52
Palmer, Dr. G. T., i, 323
Palm Family, xiii, 188
Palmitic Acid, viii, 220, 221, 350
Palm Kloof, xiv, 369-70
Palm Oil, African development and, xiii, 11;
source, xiv, 383;
vegetable fat, viii, 246
Palm-Oil Tree, xiii, 188
Palms, cocoanut, xiii, 219-20;
first appearance, xiii, 319;
in tropics, distribution of, xiv, 368;
leaves of, xiii, 176;
monocotyledons, 178;
trunks of, 26
Paloverde, leaves of, xiii, 379
Pamias, rock disintegration on, xiv, 73-4
Pamlico Sound, bar of, xiv, 264
Pampas, absence of trees in, xiv, 381;
armadillo burrows on, xii, 284;
cattle-raising and agriculture on, xiv, 384;
dust whirls, i, 60;
flatness of, xiv, 158, 216;
grass and other plants of, xiii, 375-6;
grasses, drying of, xiv, 381;
horses of, xii, 307;
true plains, xiv, 218
Pampas-Cat, xii, 364
Panacea, x, 16
Panaceas, medicinal, x, 41
Panama Canal, Caribbean traffic, i, 282;
Chagres River and, xiv, 195;
dredges used, v, 255-6;
material excavated, 258

Panama Canal Zone, health conditions, i, 327, x, 162;
sanitary control, costs, xiv, 344, 356;
temperatures, i, 209
Panama, Isthmus of, anteaters of, xii, 283;
earthquakes on, xiv, 331;
pearl fisheries of, xii, 62;
sea devils of, 150;
temperature, i, 208-9;
yellow fever extermination, x, 162, xiv, 356, 357

Pancreas, functions of, ix, 237, x, 330, 347;
secretin effects on, 325

Pancreatic Juice, viii, 358, ix, 237-8, 242, x, 325-6, 330;
of infants, ix, 346
Pangolins, xii, 281
Pangong Lake, Tibet, xiv, 211
Panpipes, xv, 315 (fig.), 316
Panspermia, xii, 9
Panthers, xii, 363;
stalking of game, xi, 224
Pantograph, in trolley systems, vii, 197
Papaw, origin, xiii, 226
Paper, electrical conductivity, iv, 259;
electrification by tearing of, 260;
heat conductivity, 179;
making of, v, 289-99, 380;
making of, in ancient Egypt, xvi, 72;
made from corn fiber, xiii, 213;
made from mulberry, v, 290, xiii, 244;
made from spruce wood, 10, 236;
Manila, 240;
origin of name, xv, 157
Paper Machines, v, 295-9, 377
Paper, Mulberry, xiii, 244;
bark as cloth, xv, 256-7
Paper Pulp, making of, viii, 153
"Paper Sailor," xii, 78
Paper Showers, i, 359
Papier-Maché, ancient, xvi, 73
Papillæ, xi, 70-1
Papin's Digester, iv, 170-1
Papuans, hair of, xv, 38;
prayer, 346
Pappus, Greek author, xvi, 94-5
Papyrus, v, 289;
Egyptian, xvi, 72
Paracelsus, x, 46-50;
classifying tendency of, 83;
compared with Vesalius, 53;
followed by Van Helmont, 68;
Locke on, 75
Parachutes, v, 234

"Paradise Lost", quotations, ii, 36, 210-11, 350

Paraffin, viii, 51, 208;
combustion of, 52;
meaning of name, 206, 380;
melting requirements, iv, 162
Paraffin Candles, viii, 247

Paraffins, Paraffin Hydrocarbons, viii, 206-210, 241;
contrasted with benzenes, 232-4;
defined, 380;
derivatives, 210-32;
molecule configuration, 233;
residues in benzenes, 235-6, 238-40;
unsaturated, 230-2
Paragreles, i, 341, 378
Parallactic Motion, ii, 317
Parallax, ii, 311-18;
Galileo's method, 55;
Hipparchus on, 32;
in distance perception, xi, 182;
photographic study, ii, 137, 314
Parallel Forces, resultant of, iv, 99

Parallel-veined Leaves, xiii, 32, 37 (fig.), 176, 177, 178

Parallelogram of Forces, v, 184-6

Paralysis, electric treatment, vi, 17, vii, 238

Paranthelion, i, 378
Parantiselenæ, i, 378
Para Rubber, xiii, 246-7
Paraselanæ, i, 180, 183, 378
Parasitic Clouds, i, 104, 378
Parasitic Plants, xiii, 15, 21, 100, 364
Parasitology, xvi, 181
Parchment Paper, strength, viii, 255

Paré, Ambroise, x, 46, 54-6, 97, 129, xvi, 108

Pareira, "Materia Medica", xvi, 186
Parental Instinct, xi, 56
Parental Solicitude, xi, 149
Parents, care of children, ix, 352;
children's resemblance to (see Heredity);
pleasure of, in children, 153

Parhelia, Parhelic Circles, i, 179-80, 181, 183, 378

Parian Chronicle, meteor recorded in, ii, 284
Paris, balloons in siege of 1871, v, 225;
bombardment in World War, 369-70, iv, 201-2;
Salpêtrière Hospital, xvi, 184;
sewage disposal, viii, 327
Paris Green, viii, 169
Paris-London Air Service, i, 44-5, 95, 285-6
Paris Observatory, ii, 58
Paris, University of, founded, xvi, 100;
medical school, x, 38
Park, Mungo, xvi, 123
Park Cattle, xii, 331
Parker, morphology studies, xvi, 140-1
Park Forests, xiv, 374
Parkinson, James, x, 112
Parklike Landscapes, xiii, 374-5, 376
Parliament, British, gold mace of, xv, 208
Parmenides, Greek philosopher, xvi, 84
Paros, fossils in rocks of, iii, 14
Parrakeet, Carolina, xii, 266
Parrots, xii, 265, 266-7;
dyeing of, 179;
monogamous, xv, 276
Parsec, astronomical unit, ii, 315
Parsley, xiii, 200-1, 223
Parsnips family, xiii, 200-1;
origin, 223;
swelled roots, 19
Parsons Steam Turbine, v, 150-1, 382
Particles, technical meaning, iv, 382

Partridge Berry, crossbreeding devices, xiii, 122;
in madder family, 205;
illustration, 96
Partridges, xii, 261

Pascal, Blaise, atmospheric pressure studies, iv, 114-16;
mathematical work, xvi, 105, 114, 119;
vacuum studies, 110
Passenger Aircraft, i, 41-3, 44-5, 50
Passerine Birds, xii, 268-9
Passiflora, origin, xiii, 226
Passion Flower, tendrils, xiii, 112
Passions (see Emotions)
Past comparisons with present, vii, 76
Pasteboard, making of, v, 299
Pasteur, Louis, x, 136-44, 208;
bacteria studies, xvi, 143, 182, 184, 185;
chemical work, 163-4;
courage of, x, 101;
Lister and, 144, 145, 146;
references to work of, 107, 132, 133
Pasteurization, x, 139-40
Pasteurized Milk, xiii, 71, x, 132, 140;
scurvy from, 266;
vitamines in, 263, ix, 347
Pastries, as food, x, 273, 315
Patagonia, bushlands of, xiv, 381;
huanacos of, xii, 313;
plains of, xiv, 218;
rhea of, xii, 249;
tides of, xiv, 298
Patagonians, height of, xv, 39
Patches of Peyer, x, 287-8
Patella, ix, 69, 70 (fig.)
Patent Medicines, remarks on, vii, 241
Pater Noster, in Aztec, xv, 169
Pathfinders, of flowers, xiii, 134, 140

Pathogenic Germs, x, 194-5 (see Disease Germs)

Pathological Anatomy, Morgani's work in, x, 98

Pathology, Cellular, founded by Virchow, x, 119, 128

Patriotism, sentiment of, xi, 145, 151
Pavloff, Ivan, x, 131, 319
Pavlov's Law, xi, 198, 201
Pay-as-you-enter Cars, vii, 184
Peach Trees, xiii, 197, 226
Pea Family, xiii, 198-9;
antiquity, 324-5;
fertilization, 137-9;
food devices, 97-8;
nitrogen-fixing parasites, i, 35, xiv, 66;
seed dispersal by, xiii, 339, 347
Peake Deep, xiv, 289
Peanuts, oil of, ix, 28
Pearl Islands, xii, 62
Pearls, finding by X-rays, vii, 256;
origin, xii, 62-3, 66
Pearly Nautilus, xii, 75-6;
evolution of, iii, 273-5
Pear Psylla, honeydew of, i, 351-2
Pearson, eugenic studies, xvi, 157;
on artificial selection, 154;
statistical methods, 153
Pear Trees, development of fruit, xiii, 54;
in rose family, 197;
origin, 224, 226
Peary, Arctic soundings of, xiv, 22;
mirage of Crocker Land, i, 173
Peas, as food, viii, 365, ix, 34, x, 262;
crossing experiments, 231-2;
flowers, xii, 44 (fig.);
food-obtaining devices, 97;
leaf-tendrils, 38;
leaves, 36-7, 113;
origin, 223;
petals, 47, 190;
pods, dry fruit, 54;
seeds, 56;
sleeping of leaves, 88-9
(see also Pea Family)
Peat, elements, iii, 345;
formation, xiii, 68, 313;
in relation to coal, iii, 344;
in sheep plant, xiii, 380;
per cent of carbon in, viii, 44;
wood fiber seen in, 45
Peat Bogs, dust from burning, i, 56, 57;
extent of present, v, 173;
of Denmark, xv, 87
Pebrine, Pasteur's study of, x, 140
Peccaries, xii, 310-11;
jaguars and, 362
Pekans, xii, 350, 351
Peking, Temple of Sun, ii, 26
Pelagic Fauna, xii, 16

Pelee, Mount, eruption, iii, 102-3, xiv, 28, 325;
dust from eruption, i, 58, 59;
earthquakes preceding eruption, xiv, 338
Pelée's Hair, iii, 105
Pelicans, xii, 254
Pellagra, x, 265, 268;
cause of, viii, 351;
eruptions on uncovered surfaces, x, 254
Pelterie, R. Esnault, v, 175-6
Pelton Wheels, v, 77-9, 80, 81, 170, vi, 368
Pelvis, ix, 63, 66-7 (fig.);
in man and apes, xv, 58;
vestiges of, in snakes, xii, 213
Pelycpoda, xii, 58-63
Pemba, clove production, xiii, 263
Penang, clove trees, xiii, 262
Penck, Prof., climate studies, xiv, 361;
land and water curves, 26
Pendulum, discovery, v, 63-5;
Galileo's observations, ii, 53;
gravity action on, iv, 97-8;
oscillations and regulation of, 147, 225, 226;
types in clocks, v, 73, 74
Pendulum Clocks, invention, ii, 58;
escapement, v, 73-4;
regulation to temperature, iv, 147
Peneplains, iii, 30, 34-5, 381;
cretaceous, 232
Penetrating Radiation, i, 143-4, 146, 379
Pennsylvania, coal beds, iii, 199, 347-8;
former volcanoes, xiv, 318;
glacial soil of, 70, 170;
natural gas, iii, 355
Pennsylvanian Period, iii, 198-202;
coal deposits, 198-201, 345;
insects, 279;
plants, 252-4
Pennyroyal, source, xiii, 205
Penguins, xii, 251
Penstocks, vi, 363
Pentane, derivatives, viii, 210
Pentose, viii, 229
Pentstemon, corolla, xiii, 201
Penumbra, of shadows, iv, 332-3
Peony, pollen of, xiii, 124
Pepin, Lake, xiv, 202
Pepo, xiii, 54
Pepper, black, xiii, 265;
red, 223
Peppermint, viii, 251, 252

Pepsin, in gastric juice, ix, 235, x, 320, 326

Peptones, x, 277
Pepys, Samuel, "Diary" quoted, iv, 53
Per, defined, viii, 380
Perceptions, defined, xi, 160-2;
differences in power of, 152;
Greek theories, xvi, 87;
misinterpreted, x, 358;
of color, ix, 114-17;
of light and shade, 105;
of objects, 105-11;
of space, xi, 162-91;
of time, 192-6;
relativity of, xvi, 85
Percussion, in diagnosis, x, 99, 110, 371
Percussion Cap, viii, 145
Percussion Drills, v, 129, 261-2, 263
Percussion Shells, v, 372
Percussive System, of oil boring, v, 265-7
Perennials, buds, xiii, 53;
roots, 16;
planting tables, 289-96
Perfection, Man's struggle for, xv, 38-9
Perfumes, chemistry of, viii, 251-2
Pericles, reference to, x, 20
Peridot, iii, 334
Perier, Pascal and, iv, 114-15
Perigee, defined, ii, 197
Perigord District, human relics, iii, 304-5
Perihelion, defined, ii, 50, 275
Period, technical meaning, iv, 383
Periodic Breathing, x, 340

Periodic Classification, viii, 177-83, 307, 309

Periods, Geological, iii, 19-21, 381
Peripatus, xii, 81
Perique Tobacco, xiii, 258
Periscopes, v, 200-1
Peristalsis, x, 327
Peritonitis, asepsis in, x, 147;
causes of, 195, 288
Periwinkles, xii, 71
Perkins Ice Machine, v, 358, 379
Perlite, viii, 160, 274

Permanent Magnets, iv, 243, vi, 30, 37, 117, vii, 372;
care of, vi, 34, 38;
lifting force of, iv, 289
Permian Period, iii, 20, 202-5, 381
Perpetual Motion, v, 97, vi, 214, xvi, 135
Perpetual Snow Line, iii, 59
Perpetuation of the Race, ix, 324-44;
marriage and the family, xv, 273
Perret, Prof. F. A., i, 194
Perrine, astronomer, ii, 136, 146, 262, 362
Perseids, ii, 288
Perseus, star clusters in, ii, 336, 343

Persia, ancient, Mediterranean aims, xiv, 306;
astronomy of ancient, ii, 26;
cheeta of, xii, 365;
climate changes, xiv, 361-2;
lions of, xii, 359;
magi of, xvi, 59;
plateau of, xiv, 222;
sun-worship, ii, 20;
use of opium, xiii, 253;
wild asses of, xii, 308
Persian Cats, xii, 356

Persian Gulf, first civilization around, xvi, 47;
pearl fisheries of, xii, 62
Persian Language, xv, 162;
words from, in English, 161
Persimmons, xiii, 226, 352-3

Persistence of Vision, iv, 346-7, v, 329, vi, 155

Persistency and will, xi, 264

Personal Equation, xi, 156

Personal Hygiene, disease prevention through, x, 302-17;
teaching of, 283-5
Personality, changed in emotion, xi, 134;
dreams as revelation of, 302;
loss of, in crowds, 324, 325-6, 329-30;
source, 33;
splitting of, in hysteria, x, 360-1, 362
Perspective, xi, 181-2;
in distance perception, ix, 119-20

Perspiration, absorption by various materials, x, 307, 308, 309;
amount of "insensible," 70-1;
caused by fear, xi, 131,132, 133;
constitution of, x, 310;
humidity and, i, 77;
temperature regulation by, 317, v, 348-9, ix, 169, x, 251, 274

(see also Sweat, Cold Sweat)
Peru, ancient use of cocaine, xiii, 254;
ancient corn-growing, 212;
ancient stone structures of, xv, 271;
conquest of, xiv, 250;
foot plow of Indians, xv, 236 (fig.);
harbors and commerce, xiv, 265, 266;
Incas (See Incas);
rainfall and fog, i, 95, 96-7;
rain-tree, 352;
source of quinine, xiii, 251;
words derived from, xv, 161

Peruvian Art, ancient, xv, 297 (fig.), 311 (fig.)

Peruvian Bark, xiii, 250-1
Peruvian Earthquake, xiv;
tidal waves of, xiv, 337
Peruvian Paint, i, 96-7, 378

Pessimism, physical causes, xi, 339, 369-70, 372

Pestles, xv, 238-9
Petals, of flowers, xiii, 45, 47;
importance in classification, 47;
first appearance, 318;
lacking in some flowers, 46
Peter Pan, story of, xv, 330
Peters, Dr., of Hamilton, ii, 256
Petiole, of leaves, xiii, 34, 35
Petit, Jean-Louis, x, 90-1, xvi, 161
Petrels, xii, 251, 252

Petrified Animals and Plants, iii, 15-16, 126-7

Petroleum, composition, products, and supply, viii, 208-10;
fluorescence of, iv, 323, 379-80;
origin and occurrence, iii, 348-54;
production and supply (U. S.), v, 172-3;
supply and approaching exhaustion, vii, 309
Petrology, iii, 381, xvi, 170
Pfeiffer, immunity theory of, x, 211;
influenza germ discovery, 295
Phaestos Disk, xv, 176 (fig.)
Phagocytosis, x, 209-10
Phaleropes, xii, 262
Phanerogams, xiii, 62-3;
reproduction, 117-54 (see Flowering Plants)
Phantasies, in psychoanalysis, x, 365
Phantom Circuits, vii, 105-6, 119
"Pharaoh's Chicken," xii, 260
Pharmacognosy, xiii, 249
Pharmacology, x, 381, xvi, 186;
chemical, founded by Paracelsus, x, 50
Pharmacy, history, xvi, 186-7
Pharnyx, condition in thirst, xi, 66
Phase (electricity), defined, vi, 204-5;
"in," 168;
"out of," 167, 204

(see also Single-Phase, Two-phase, Three-phase)

Phase Law (chemistry), xvi, 136, 164
Phase Relations, vi, 167-9, 171-4
Phases, of Mars, ii, 227;
of moon, 190, 193-5, 196
Phasing-in, defined, vi, 263, 342
Pheasants, xii, 261;
hearing of, i, 188
Phenology, i, 254-6, 379
Phenolphthalein, viii, 294, x, 378
Phenols, viii, 236, 237-8, 380;
as disinfectants, 333
Philadelphia, summer of 1816, i, 360;
water supply of, xiv, 140;
yellow fever epidemic, x, 159

"Philadelphia Ledger," first Hoe press, v, 301

Philippine Islands, aerial exploration work, i, 47;
baguios, 136;
beriberi in, ix, 35, x, 257;
carabao of, xii, 329;
civilization in mountain valleys, xv, 131;
continental islands, xiv, 274;
copra production, xiii, 220;
dipterocarp forests, 350;
fiber-wear, 236;
fire obtained by friction, viii, 89;
fire by air-compression, v, 128;
Manila hemp, xiii, 239-40;
new volcano in Camiguin, xiv, 320;
ocean depths near, iii, 51;
octopod fishing, xii, 78;
rainfall at Baguio, i, 110;
rice growing, xiii, 213, 214;
Weather Bureau, i, 223
Philo of Byzantium, thermoscope, i, 69
Philosophers, Faraday on, x, 376
Philosopher's Stone, xvi, 14
Philosophy, Greek, xvi, 76-80, 83-8, 99;
18th century, 117;
mediæval, x, 35;
recent, xvi, 195-8;
Roman and Mediæval, 99-100;
science and, 112, 115;
social spirit and, 195
Philostratus, on death of Domitian, ii, 221;
on sun, 165
Phlegmatic Temperament, xi, 153
Phlegraean Fields, xiv, 225, 316, 320
Phlogopite, iii, 334
Phœnician Language, xv, 162

Phœnicians, Africa circumnavigated by, xiv, 196;
commerce of, 307;
in Iberian group, xvi, 49;
introduction of cats by, xii, 355;
invention of Alphabet, xv, 175;
navigation of, v, 182;
ships of, xiv, 265
Phonisms, xi, 222
Phonograph v, 328-9, 381;
combined with motion pictures, 331;
making of records of, iv, 240;
motor-driven, vii, 87;
vibration rates in, ix, 101
Phosgene, viii, 263, x, 187
Phosphate Baking Powders, viii, 136
Phosphate Group, viii, 93
Phosphate of Lime, plant needs of, xiv, 67

Phosphate Rock, as fertilizer, viii, 89, 344, 345;
occurrence and supply, xiv, 67
Phosphates, derivation and uses, viii, 89;
fertilizers, 153, 279-80;
in blood, x, 280;
in urine, x, 343;
test, viii, 290

(see also Calcium Phosphate, Sodium Phosphate)

Phosphine, viii, 89
Phospholipins, viii, 351
Phosphorescence, iv, 380;
of decaying wood, i, 346;
of marine animals, xii, 18-20, 24, 84
Phosphoric Acid, composition, viii, 89, 115;
in body, x, 280;
plant needs and sources, xiv, 67, 68, 69;
salts from, viii, 116;
solubility, 112;
stability, 115
Phosphorus, viii, 18-19, 87-9;
burning under water, 54-5;
ignition point, 53;
in body, functions, 354-5;
in fertilizers, 343, 344-5;
in iron ores, iii, 356;
melting requirements, iv, 162;
plant needs of, viii, 337, 341, 342, 344-5, ix, 29;
sources, viii, 345;
symbol and atomic weight, 383

Phosphorous (plant), ancient name of Venus, ii, 191

Phosphorus Pentoxide, viii, 87, 89
Photisms, xi, 222
Photochemical Climate, i, 325, 379
Photo-engraving, xvi, 129

Photographic Action, of different colors, iv, 365-6

Photographic Films, composition, viii, 255;
invention, v, 330-1
Photographic Map-Making, i, 45-8
Photographs, savage ideas of, xv, 331;
X-ray, vii, 250, 253-4
Photography, chemistry of, viii, 171-3;
color, iv, 368-9;
history, xvi, 192;
in astronomy (see Astronomical Photography);
in aurora studies, i, 162;
in lightning study, 146-8;
lenses used in, iv, 373;
underwater, i, 47-8
(see also Camera)
Photometers, vii, 374
Photosphere, defined, ii, 173
Photosynthesis, xiii, 81, 105, 109;
in cactus plants, 378
Phrenic Nerve, xi, 37
Phrenology, ix, 145
Phrygian Stone, ii, 284
Phylum, Phyla, xii, 29
Physas, xii, 69, 71

Physical Changes, contrasted with chemical, viii, 14-15

Physical Characters, classification of man by, xv, 36-47

Physical Chemistry, viii, 296-316
Physical Examinations, x, 370-1
Physical States of Matter, viii, 22, 382;
changed by heat, iv, 139, 151-3;
chemical interpretation, viii, 296-316;
in relation to pressure and temperature, 303-5;
suspended changes, 113, 304, 305

Physical Training Exercises, x, 305

Physicians, Babylonian laws controlling, x, 14-15;
capacity and preparation of, 367, 369;
earliest distinction from surgeons, 16-17;
essential duties of, 21, 75-6;
Oath of Hippocrates, 18-19;
Paracelsus on province of, 49
Physics, Volume iv
Physics, branches of, iv, 50;
concrete science, xvi, 42;
daily applications of, iv, 10, 187, xvi, 17, 19, 30;
defined, 36;
energy the subject of, iv, 12, 13-14, 50;
exact, positive science, x, 368;
history of development of, iv, 11, 18-20, 24-30, xvi, 54, 82, 89, 91-2, 101, 103, 105, 109-10, 129-38;
interrelation of phenomena of, iv, 39, 40;
measurements in, iv, 45, xvi, 129-30;
medicine and, x, 81, 369;
realm of, iv, 13-20;
technical terms, glossary, 381-4
Physik, Philip, x, 121
Physiography, Volume xiv
Physiography, defined, iii, 381, xvi, 36
Physiological Meteorology, i, 316-31
Physiology, Volume ix

Physiology, daily applications, xvi, 15, 16-17;
history of development, x, 29, 30-1, 81, 125-8, xvi, 82-3, 180;
medicine based on (Boerhaave), x, 76-7;
science of body, xvi, 37;
teaching of, remarks on, x, 284-5
Piano, automatic, vi, 97;
evolution of, xv, 318;
intervals on, iv, 208;
sympathetic vibration, vii, 261-2;
vibration rate of notes, ix, 99
Picard, astronomer, ii, 58, 59, 64
Piche, A., deperditometer, i, 319
Pickerel Frogs, xii, 180
Pickerels, xii, 163

Pickering, Prof. Edward C., astronomical work, ii, 17, 116, 118, 122, 127, 130, 132-3, 133, 145, 146, 233, 237-8, 297, 307, 359

Pickering, W. H., ii, 271
Picric Acid, viii, 63, 238, 262
Pictou, Nova Scotia, pollen shower, i, 359
Picture Writing, xv, 167-9
(see also Hieroglyphics)
Pictures, depth impressions in, ix, 120
Piddington, Henry, i, 135
Piddocks, xii, 59
Pie Crust, "taste" of, xi, 127
Piedmont Glaciers, iii, 60
Piedmont Plateau, xiv, 27-8, 213;
building stones of, iii, 371, 372;
forests of, xiv, 378;
geology, iii, 28, 112, 172, 188, 231-2
Pig Iron, v, 318, viii, 157, 158, 159;
electric furnace production, vii, 312
Pigeons, xii, 265;
equilibrium disturbances in, x, 126, xi, 31
Pigments, viii, 162, 264, 265-6;
ancient, xv, 113-14;
colors of, iv, 369-70
Pigs (swine), xii, 310-11;
evolution of hoof, iii, 300
Pikas, xii, 287-8
Pikes (fish), xii, 163
Pike's Peak, shadow in sky, i, 170
Pile-driving, by water jets, v, 88-9
Pileus, of mushrooms, xiii, 163
Pilgrim Shell, xii, 65
Pili Erectores, xi, 113
Pillows, and sleep, xi, 290
Pillsbury, Prof., quoted, xi, 168-9
Pilot Balloons, i, 21-2, 312, 379
Pilot Charts, i, 273-5
Piloting, wireless system, vii, 285
Pilot Lights, vi, 276
Pilot Snakes, xii, 219-20, 233
Piltdown Man, xv, 92-5;
brain of, 96;
implements of, 107;
period of, 102
Pimento, origin, xiii, 265
Pimpernel, xiii, 203
Pimples, ix, 186, 187;
germs of, x, 201

Pineapple, American origin, xiii, 221, 226, xiv, 382;
fiber of leaves, xiii, 236;
introduction, 10;
water-holding leaves, 106

Pineapple Family, in tropical forests, xiii, 362-3;
restricted to America, 320

Pine Forests, conditions favorable to, xiii, 371;
pollen showers, i, 359
Pinel, Philippe, x, 110-11
Pine Needles, measuring heat in, vi, 62-3

Pine Trees, in American forests, xiv, 372, 374;
lightning dangers, i, 155;
planting conditions, xiii, 270;
pollen of, 118, 149;
polycotyledons, 60;
seeds of, 345;
seed-dispersal, 343;
wind-fertilization, 148
(see also Conifers)
Pinhole Camera, ix, 107-8, 109
Pinion Gears, v, 29, 30 (fig.)

Pink Family, petals and sepals, xiii, 194, 195

Pink Lady's Slipper, xiii, 145 (fig.)
Pinks, meadow, xiii, 133-5;
sea or marsh, 204
Pinuela, origin, xiii, 226
Pipal Tree of India, xiii, 108
Pipefishes, xii, 163

Pipe Organ, of Ctesibius, v, 110-11 (see Organs)

Pipes, lead, viii, 162
(see also Water Pipes)
"Pipes", in ingots, v, 323
Pipes of Pan, xv, 316, 315 (fig.)
Pipette, viii, 294, 295 (fig.)
Pipe Vine, fertilization, xiii, 131-3
Piracy, Stream, iii, 38-9, xiv, 177-83
Piranha, xii, 159
Pirogoff, Nikolai, x, 131
Pisa Cathedral, lamp in, ii, 53, v, 63-4
Pisa, Leaning Tower (see Leaning Tower)
Pistillate Flowers, xiii, 46-7
Pistils, xiii, 45, 46;
in reproduction, 117-22;
of highly cultivated plants, 51
Pistons, measurement of work of, vi, 81-2;
reciprocating and rotating, v, 148;
service in internal combustion engines, i, 57-9

Pita, origin and product, xiii, 244

Pitch of Sounds, iv, 205-6, ix, 99-100, xi, 104, 105;
extremes of audibility, iv, 204;
hearing of, xi, 103;
modulations of, in voice and music, iv, 209;
motion effects on, iv, 209-10;
of bells, 222;
of organ pipes, 230-1, 231-2;
of vibrating strings and rods, 223-4;
resonators for special, iv, 232, 233;
temperature effects on, 231-2
Pitchblende, radium from, xvi, 193
Pitcher Plant, xiii, 39-40

Pith Balls, electrification of, iv, 257-8, vi, 286-7

Pithecanthropus Erectus, iii, 302-3, xv, 88-92;
brain of, 96;
period of, 102
Pittsburg, dryness of, i, 337;
growth as river city, xiv, 219;
smoke nuisance, i, 64, 65;
"Smoky City", vii, 343;
water supplies of, viii, 318;
water supply and typhoid rate, 322

Pittsburg Bituminous Coal Bed, iii, 200-1, 347

Pituitary Gland, x, 347

Plaaters Kill, xiv, 179

"Place in the Sun", struggle of plants for, xiii, 27-8, 38-9, 76-7, 361-3

Placental Animals, iii, 297, 298;
evolution of, xii, 271, 332
Placer Deposits, defined, iii, 381;
gold, 331, 365-6, 366-7;
platinum, 335;
tin, 369
Plagioclase, iii, 328-9
Plague, Greek ideas of, x, 285;
immunity to, 207;
inoculation against, 208;
racial susceptibility to, xv, 50, 51
Plagues, great, x, 153-70;
uncleanliness and, xv, 49
Plains, xiv, 212-19;
civilization in relation to, xv, 128;
define and distinguished, xiv, 27, 213, 220;
Great (see Great Plains);
outwash, iii, 68-9;
perfect, seldom attained, 35;
populations mostly on, xiv, 218-19;
sea-cut, 46-7, 216;
surfaces of high and low, 28
Planarians, xii, 44
Plane of Ecliptic, ii, 70, 163
Planers, invention, v, 47
Plane Tree, in landscaping, xiii, 271-2;
leaf buds, 34
(see also Sycamores)
Planet Deep, iii, 51
Planetary Motions, ii, 163, iii, 158, 159;
compared with whirling of pail, iv, 71;
Copernicus on, ii, 43-4;
gravitation and, iv, 95, 98;
Huygen's studies, ii, 58;
irregularities, 66, 67, 71, 73, 79, 87;
Kepler's laws, 49-52;
Ptolemaic theory, 35-6;
spectroscopic investigation, 120-1;
theory of relativity and, 80-1;
tidal friction theory, 376-7
Planetary Nebulæ, ii, 360;
distribution and motion, 364;
star streaming by, 347;
stars and, 308-9
Planetary Orbits, ii, 162-3;
deviations, 66, 67, 79;
elliptical form, 39, 50-1, xvi, 102;
first thought to be circular, ii, 34, 49;
variations in elements, 74-5

Planetesimal Hypothesis, ii, 372-4, iii, 160-3;
not sustained by Mt. Wilson studies, ii, 157;
origin of moon by, 376;
rings of Saturn by, 266
Planetesimals, ii, 374, iii, 161, 162

Planets, atmospheres of, i, 10, ii, 231-2, 245;
conjunction recorded by Hindus, 21;
days and seasons in, 228;
distances and periods, 51-2;
erratic amplitudes, 25;
farthest, 267-9;
hypotheses of origin, ii, 369-74, 379, iii, 160, 162;
inner, ii, 189-92;
law of sun's attraction, 65;
life on, 245-50;
lucid, 264;
minor, 16, 254-9 (see Asteroids);
motions (see Planetary Motions);
orbits (see Planetary Orbits);
photography in study, 130-4;
sizes and motions, 162-3;
of stars, 252-3;
trans-Neptunian, 270-2;
weighing of, 75-7
Plankton, Sea, xii, 17-21, xvi, 147-8;
copepods in, xii, 84;
one-celled animals of, 25
Planning, of work, xi, 377-8
Planosphere, xvi, 91
Plantain Eaters, xii, 265
Plantains, xiii, 217, 226
Plant Breeding, ix, 327, 337
Plant Classification, xiii, 168-81;
by cotyledons, 60-1;
by factor expressions, 330;
by morphological characters, xvi, 165-6;
by reproductive processes, 166-7;
former method, xiii, 175;
Linnæan System, x, 84;
outline, iii, 251
Plant Distribution, xiii, 337-84;
determined by climate, xiv, 364-79, 380-1;
facilitated by land arrangement, xiv, 21;
Ice Age and, xiii, 321, xiv, 375-7;
importance of study of, xiii, 12;
land changes and, xiii, 320
Plant Ecology, xiii, 354-7
Plant Families, xiii, 179-207;
restricted areas of some, 320

Plant Formations, xiv, 371-2, (see Plant Societies)

Plante, ball lightning studies, vii, 215
Planting, index plants, i, 255-6;
rules and tables, xiii, 267-97
Planting Machines, v, 244

Plant Kingdom, distinguished from animal, xii, 14-15, xiii, 13-14;
history of, xiii, 298-336
Plant Names, xiii, 168-71
Plants, active principle, xiii, 250;
adaptations in (see Adaptation to Environment);
aerial, xiii, 21;
ancient study, 249;
animals and, interdependence, viii, 334-5, 347, 349, 350, xiii, 82;
autophytic, 96-7;
behavior, 76-115;
blended characters in, ix, 337;
borrowing and robbing, xiii, 97-101;
breathing of, 109;
Brownian movements, xvi, 166;
carbon dioxide used by, i, 13-14, viii, 49;
cell constituents of, ix, 26;
cellulose of, 30;
chemical composition and processes, iii, 344, viii, 335-8, 341, 348, 349, 354-5, xiv, 64-5;
chlorophyll (see Chlorophyll);
chromosomes in different species, ix, 46;
classification (see Plant Classification);
climate and, xiv, 363;
colorless, xii, 14-15;
cultivated (see Cultivated P.);
defined, xiii, 13-14;
distribution (see Plant Distribution);
distinguished, xii, from animals, vii, 14-15;
evolution, iii, 249-58;
flowering and flowerless (see Flowering, Flowerless Plants);
fog drip, i, 351;
food and feeding, viii, 339-46, 347, 349, 350, xiii, 13-14, 17-18, 19, 23, 24, 25-6, 39-41, 42, 90-101, xiv, 64-8;
food of green and other, xiii, 70;
food-making and storage by, viii, 334, ix, 25-30, xiii, 77-84, 95, 96;
food varieties for man and animals, ix, 24-5, 30;
frost protection, i, 259;
frost susceptibilities, 258;
galls on, xii, 125;
garden (see Garden Plants);
geotropism, xiii, 85;
growth electrically stimulated, vii, 351-3;
growth, upward and downward, xiii, 84-5;
guttation, i, 350-1;
highly cultivated, xiii, 51;
hybrid, 147;
immobility, 14, 109-10;
index, i, 255;
inheritance laws, x, 231, 232;
injured, hasty flowering of, xiii, 167;
insect-capturing, 39-41;
instinct in, xi, 49;
land (see Land Plants);
light effects on, x, 253;
marine, xii, 16-17;
microscopic (see Bacteria);
modern, origin and development, xiii, 316-25;
movements, 109-15;
motion pictures of growth, iv, 348;
mutation (see Mutants);
new species, how developed, xiii, 325-36;
nitrogen needs, i, 34, viii, 280, 345-6, xiv, 66;
nitrogen supply in soil, x, 193-4;
northward movement, xiii, 321;
number of species, 323;
of oceanic islands, xiv, 277, 278;
oils of, ix, 28;
parasitic, xiii, 100 (see Parasitic Plants);
parts of, 15;
petrified, iii, 15-16;
phenology, i, 254, 256, 379;
protective methods (see Protective Methods);
proteins of, ix, 278-9, 280, 287;
protoplasm of, xiii, 74;
rate of increase in, xv, 19, 21;
reasoning in, xiii, 3, 97;
reproduction, 116-67 (see Reproduction of Plants);
restless and irritable, 109-15;
rock disintegration by, viii, 194, 338;
rootless, xiii, 15, 21;
salt and fresh water, ix, 174, 175;
saprophytic, xiii, 99-101;
seat of life in, ix, 17;
seed-dispersed (see Seed);
struggle for dominance (see Struggle for Dominance, Struggle for Existence);
sunlight and, ix, 27, xi, 52, xiii, 76-7, 84-90, 361-3, xiv, 365-6, 367;
unicellular and multicellular, xiii, 166;
uses to man, 9-12, 208-66;
variation in, xv, 22-3 (see Variation);
vascular and nonvascular, xiii, 65-6;
water sources and uses, 90-6, 101-9;
water storage, 28, 41-2, 106-7, 378, 379, 380
(see also Vegetation)
Plant Societies, xiii, 356-83, xiv, 371-2
Plaskett, reflector of, ii, 106-7
Plaster of Paris, iii, 332, viii, 153;
made from gypsum, xiv, 209;
manufacture of, iii, 376
Plastic Surgery, x, 57, 189, 384
Plateaus, xiv, 220-4;
dissection and destruction, 224;
distinguished from plains and mountains, 27-8, 213;
formed by warping, 38;
mountains from dissected, iii, 139-40, xiv, 225, 226;
oceanic, 286;
re-elevated, 96-8;
topography developed from stratified, 80-1
Plate Condensers, vi, 293-4
Platelets, of blood, ix, 188-9;
held by capillary walls, 194
Plates, photographic, viii, 172-3
Platiarius, Joannes, x, 37
Plating of Metals (see Electroplating)
Platinum, iii, 335, viii, 126-7, 173-4;
affinity intensity, 128;
atomic weight and symbol, 383;
catalyzer, 82, 103;
coefficient of expansion, vi, 265;
density of, iv, 113;
electrical conductivity, 283;
extraction from ores, viii, 131;
melting point, iv, 162, viii, 384;
occurrence, 131, 198;
positiveness of, vi, 59;
specific gravity, viii, 384
Platinum Metals, viii, 173
Plato, classifying fault of, x, 83;
greatness of, 20;
on forms and knowledge, xvi, 87, 88;
on passions, xi, 130
Platte River, overloading results, xiv, 161;
sediment deposited, iii, 32-3
Platyhelminthes, xii, 44
Plauen Laces, v, 288
Play, of animals and men, ix, 21, xvi, 143
Playfair, xvi, 170
Pleasure, artistic forms of, xv, 296-325;
emotions of, ix, 153, 165;
significance of, xi, 121-2;
stimulation requisite, 195
Pleiades, star cluster, ii, 122, 336;
in moving cluster, 343;
nebulosity, 110, 359-60
Pleistocene Animals, xii, 279, 306, 313, 327
Plesiosaurs, iii, 288, xii, 182, 202
Pleurisy, friction sounds in, x, 109

Pliny, harvesting machines mentioned by, v, 240;
natural history of, xvi, 98;
on Roman physicians, x, 25

Pliocene Epoch, species surviving from, xv, 71

Plovers, xii, 262
Plowing, deep, xiv, 69;
modern, v, 218, 243

Plows, evolution and kinds, v, 239-40, 241-3, xv, 235-6

Plucker, experiments of, xvi, 193
Plucking of Rock, iii, 29, 64, 65
Plumbago, viii, 43
Plumbing, of houses, how worked, v, 84-6
Plumb Lines, iv, 99
Plumed Seed and Fruits, xiii, 343-4, 345
(see also Winged Seed)
Plum Trees, xiii, 197, 271-2
Plums, drupes, xiii, 54;
origin, 226;
splitting, 94
Plutarch, on rain and battles, i, 336;
on sun, ii, 165, 220-1
Plutarch's Lives, Copernicus' study, xvi, 102
Plutonic Rocks, defined, iii, 381, xiv, 105;
exposure by denudation, 100, 105;
forms, iii, 102 (fig.), 110-12, 170, xiv, 105-11;
topography due to, iv, 105-13;
weathering of, 105-6, 107, 110, 112-13
Pneuma, x, 27, 29, 63, 85
Pneumatic Breakwaters, v, 125
Pneumatic Caissons, v, 116-21 (see Caissons)
Pneumatic Cars, v, 133
Pneumatic Cement Gun, v, 136
Pneumatic Cushions, v, 133-5
Pneumatic Dispatch, i, 29

Pneumatic Drills, i, 27, iv, 129, v, 129, 261-2, 263, 380, 381

Pneumatic Engineering origin, v, 109
Pneumatic Hammer, i, 28, v, 129
Pneumatic Motors, v, 129-30
Pneumatic Musical Toys, of Hero, xvi, 92
Pneumatic Power Transmission, i, 26, 27-8
Pneumatic Riveters, v, 129
Pneumatic School, of medicine, x, 26-7, 29
Pneumatic Shovels, v, 262
Pneumatic Tampers, v, 135
Pneumatic Tires, v, 133-4, 206, 382;
bursting by heat, iv, 151
Pneumatic Tools, i, 27-8, iv, 129
Pneumatic Trough, viii, 32 (fig.)
Pneumatic Tubes, i, 28-9, iv, 130, v, 137-8;
obstructions in, how located, iv, 200
Pneumatic Tunnel Shield, v, 122-4, 260
Pneumogastric Nerve, xi, 30
Pneumonia, x, 288-9;
discovery of cocci, xvi, 185;
germ of, x, 194, 196, 216, 221, 289;
immunity to, 207;
inoculation against, 208;
negro susceptibility to, xv, 50, 51;
toxin of, x, 196
Po (River), levees of, xiv, 53;
longitudinal character, 154
Pockels, F., i, 152-3
Pocky Clouds, i, 104, 379
Pocono Plateau, xiv, 221
Podalic Version, x, 56
Podalirius, x, 16
Pods, seed-shooting, xiii, 339
Poetry, development of, xv, 319-22, 325;
historic value of, 322, 323-4
Poggendorff's Illusion, xi, 187
Pogonip, ice fog, i, 95-6, 379
Poincaré, astronomical work, ii, 356, 377;
on relativity, xvi, 197

Pointed Objects, electric discharges from, i, 157, iv, 265, 269, vi, 295-7

Poiseuille, Jean Leonard Marie, x, 126
Poison Ivy, xiii, 252;
aerial roots, 20;
family, 200
Poisonous Amphibians, xii, 169-70

Poisonous Gases, in World War, i, 308-9, 313-14, x, 186-7;
scars of, 189
Poisonous Snakes, xii, 224-38
Poisonous Spiders, xii, 93, 95
Poisons, arsenic, 169;
carbon monoxide, viii, 50-1;
diseases from, x, 255;
effect on mind, xi, 13;
in air, ix, 270;
in plants, 30, xiii, 250, 252;
mercuric, viii, 170;
vegetable acids, 222;
wood alcohol, 214;
use of, by savages and others, xv, 227-9
Poisson, Simeon Denis, xvi, 122
Pola, harbor of, xiv, 253
Poland and Danzig, xiv, 306
Polar Bands, i, 99
Polar Bears, xii, 336-7;
Eskimo method of catching, xv, 224-5
Polar Coordinates, iv, 16
Polarimeter, viii, 226
Polaris (Pole Star), ii, 232;
a binary, 123;
color, 297;
magnitude, 295;
standard of magnitude, 297
Polariscope, viii, 309-10, x, 137
Polarity, magnetic, vii, 374
Polarization, meaning, iv, 354, 383

Polarization, in electric cells, iv, 296, 298, 383, vi, 136-7

Polarization of Light, iii, 319, iv, 353-6, 383;
discovery, xvi, 119;
Pasteur & Le Bel's studies, 163-4;
sugar testing by, iv, 354-6, viii, 226
Polar Regions, aurora in, i, 159;
clouds and fogs, 93, 95;
frozen soil, xiv, 75;
halos, i, 179;
land areas uncertain, xiv, 11, 20;
living conditions in, 344;
mirages, i, 172, 173;
plant conditions of, xiv, 365;
rain and snow in, i, 109, 119, xiv, 42;
rime in, i, 121;
sky shadows in, 170;
tundra vegetation, xiii, 381;
winds, i, 127, 128, 129
Polar Relays (telegraphy) vii, 114-18
Polecats, xii, 349
Pole Lathes, v, 42-3
Pole-line Transmission System, vii, 14-24

Poles of Earth, altitude of stratosphere at, i, 20;
aurora in relation to, 159;
compass in relation to, iv, 246;
flattening at, ii, 69;
weight of bodies at, 69, iv, 101
(see also Polar Regions)
Pole Strength, unit of, iv, 249, 250
Policeman's Whistle, iv, 220
Pollen, xiii, 118, 119;
attraction to insects, 124, 125, 134, 143;
found in ancient remains, 310;
hay fever from, x, 212;
in air, i, 61;
in aquatic plants, xiii, 149-52;
mixtures of, 146-8;
protection, 126;
"showers," i, 359;
wind-blown, xiii, 123, 148-9, 144 (illus.)
Pollution Gauge, i, 65, 379
Pollux, angular diameter, ii, 151
Polonium, discovery, xvi, 193
Polyandry, xv, 285, 286-7, 294-5
Polycotyledons, xiii, 60
Polycythemia, x, 152
Polygamy, xv, 285, 287-9
Polymerization, viii, 219, 232, 335
Polynesia, xiv, 277;
ease of life in, xv, 124;
overpopulation of, xiv, 282
Polynesians, clothes of, xv, 256-7;
fire generation by, 231;
hair of, 37;
in brown race, 37;
seamanship of, xiv, 282, 305-6;
susceptibility to tuberculosis, xv, 51;
tattooing among, 258;
wind gods of, 342
Polypeptides, viii, 353
Polypetalae, xiii, 47, 190, 195-201
Polyps, xii, 33-43
Polysaccharides, viii, 224, 227-9
Polyuria, x, 343-4
Polyzoa, xii, 46-7
Pomegranates, origin, xiii, 226
Pompeii, burying of, iii, 100;
earthquake at, xiv, 326;
volcanic material over, 326
Pomes, xiii, 54
Pondering, delays in brain, xi, 21
Ponds, depth appearances of, iv, 327;
dew, i, 352-3
Pond Snails, xii, 69
Pond-weed, xiii, 340
Pons, comet discoveries, ii, 275, 289
Pontchartrain, Lake, xiv, 203
Pontias, i, 131-2, 379
Poor Whites, of southern mountains, xv, 130-1
Popcorn, eating of, ix, 251;
known to Indians, xiii, 212
Poplar Trees, antiquity, xiii, 324-5;
earliest appearance, 318;
family, 191;
fluttering of leaves, 113;
in landscaping, 271-2;
seed dispersal, 343
Popliteal Aneurism, x, 121
Popoff, wireless system, xvi, 191
Poppy, cultivation and uses, xiii, 253-4;
seed in confections, 250, 254
Population, artificial selection, xvi, 154-5;
civilization in relation to, xv, 128-9;
distribution of, 12;
increase of, 26-7;
mostly on plains, xiv, 218;
of mountains, 245
Porbeagles, xii, 145
Porcelain, viii, 283;
Egyptian, xvi, 74
Porcupines, xii, 288-9;
absence of fear in, xi, 136
Porifera, xii, 30
Pork, calories in, ix, 299;
proteins in, 279;
trichina caused by, xv, 49;
vitamines in, x, 262
Porous Rock, water in, iii, 113-15
Porpoises, xii, 297
Portals of Entry (infections), x, 198, 201-2
Portal Vein, ix, 198, 245
Port Hudson, capture of, xiv, 194
Port Jackson Shark, xii, 143
Portland Cement, iii, 373, 374, viii, 280
Porto Bello, heavy rain, i, 110
Porto Rico, hookworm in, x, 174;
ocean depths near, iii, 51;
overpopulation of, xiv, 282;
zoölogy of, 274
Porto Rico Trench, xiv, 289
Portugal, aphysia dyes of, xii, 68
Portuguese Empire, xiv, 310
Portuguese Language, xv, 162
Portuguese Man-of-War, xii, 18, 37
Portuguese Navigators, xiv, 196, 309
Port Valais, xiv, 53

Position, perception of, xi, 162-3, 164, 165, 167-71

Positive, electrical meaning, vi, 57, 124

Positive Electricity, iv, 258, 265, vi, 287, 288

Positive Ions, i, 142, 143, viii, 121-2
Post, C. W., rain experiments, i, 339
Post, Wright, x, 121
Postage Stamps, dextrin gumming, viii, 228;
printing of, vii, 314
Postal Telegraph Company, vii, 108, 112
Post-Mortem Findings, x, 98
Postures, importance to health, x, 241-2;
importance of, to right growth, ix, 57;
mental effects, xi, 294, 301, 337, 338-40, 371, 372;
muscular activity in, ix, 83-4;
standing and walking, x, 305

Potash, available supplies and uses, viii, 275, 278-9, 344, xiv, 67-8, 69, 209;
from smoke precipitation, vii, 347, 348;
in body fluids, ix, 174;
in ground water, xiv, 142;
locked-up forms, viii, 200-1;
salts of, in protoplasm, ix, 82
Potash Lakes, xiv, 206, 212
Potassium, viii, 143-5;
affinity strength, 127, 128;
alkali metal, 132-4;
atomic weight and symbol, 383;
fusibility, 384;
in body tissues, 354;
in earth's crust, iii, 308, viii, 19, 129, 148, 192, 195, 279;
light metal, 17, 127;
metallic character, 181;
plant needs and sources, 337, 341, 342, 343, 344;
specific gravity, 384;
spectrum, 301-2;
test for, 287, 289
Potassium Compounds, viii, 144;
chlorate uses, 34, 35, 87, 88, 89, 146;
chloride, 188;
cyanide, in gold extraction, 174;
feldspar, 90;
flame color, 301;
hydroxide, in soap making, viii, 142;
nitrate, 72, 138, 144-5, 146, 372;
occurrence in nature, 130, 138, 143-4, 195, 196, 279, 344;
permanganate, 294, 333;
uses, 130, 144, 146
Potatoes, calories in, ix, 299;
eyes of, xiii, 22;
food value, ix, 34, viii, 365, x, 261, 265, 266, 268;
history and kinds, xiii, 218-19;
keeping of, viii, 371;
origin, xiii, 221, 223, xiv, 382;
starch from, viii, 248, xiii, 83;
starch storage in, ix, 27-8;
stems, xiii, 22, 23;
tubers, 24 (fig.), 83

Potential, Electrical, iv, 262-3, 383, vi, 49, vii, 374;
maintenance of constant, vi, 329;
positive and negative, iv, 265;
spark table, vii, 383

Potential Differences, iv, 263, 383, vi, 50, 51, 57, 72, vii, 366;
between earth and clouds, i, 144, iv, 269;
electric energy from, 263, 264-5, 294-5;
in thunderstorms, i, 149-50, 151-2, vii, 206-7;
measured by voltmeters, 154;
production of, iv, 271-3;
unit of, 280
Potential Energy, iv, 79, vii, 368;
conversion to kinetic, iv, 81, 82, 87-8;
forms of, 82
Potential Gradient, i, 144, 145
Potential Transformers, vii, 44, 45
Potholes, iii, 39-40
Potomac River, course of, xiv, 154, 168-9;
gap, 51, 52, 167;
rapids, 159;
shad season in, xii, 155
Pott, Percival, x, 92
Pott's Disease, x, 92
Pott's Fracture, x, 92
Potter's Wheel, xv, 249-50, 251 (fig.)
Pottery, viii, 282-3;
ancient making of, viii, 280-1, xv, 248-51, xvi, 74;
decorations of, xv, 250-1, 252, 253, 297-8
Pouched Gophers, xii, 290
Pouched Mice, xii, 278
Poulsen Arc Generators, vii, 274, 275-6, 291
Poultry, originals of, xii, 261
Poultry Products, drain on farm, viii, 342-3

Pound, unit of force and mass, iv, 58, 64-5, 69-70;
value in grams, 70, viii, 28
Poundal, unit of force, iv, 64, 69;
value in grams and dynes, 70
"Poverty Year," i, 359
Powder (see Gunpowder, Smokeless Powder)
Power, defined, iv, 80, vi, 83, 84;
electric (see Electric Power);
from fuels, ix, 15-16;
gain in elementary machines, v, 22-3, 31-5, 38;
relation to velocity in machines, iv, 92;
sources of, ix, 25-6;
unit of, iv, 80, vi, 83, 84, vii, 369
(see also Energy, Force)
Power Boats, cylinders, v, 159

Power Factor, in alternating currents, vi, 169, 172;
in induction motors, 255-6;
regulation by, synchronous motors, 255, 260-2;
in rotary converters, 348
Power Plants, vi, 349-84;
distribution of power, vii, 25-31
(see also Power Transmission);
extra charges for peak hours, vii, 177-8;
for farms, 231-4;
high and low head, v, 79-83;
interest of machinery, vi, 175-6;
number and capacity in U. S., vii, 74-5;
remote control in, vi, 100-1, 102;
Shuman's sun-using, v, 177-8;
tidal, 174-7;
turbine use, advantages, 151, 153;
use of alternators, vi, 215;
using volcanic heat, v, 179-80
(see also Hydroelectric Plants)
Power Transmission (electrical), vii, 9-31;
alternating currents in, vi, 159-61, 169, 195-6;
direct currents in, 160, 195;

Niagara Plant system, 375-8;
overhead and underground (see Overhead, Underground Transmission);
present distances attained, 365;
problem, 367-8;
prominent names in history, 26;
synchronous condensers in, 262;
traction methods, vii, 186-93, 197-200;
voltages and currents used, vi, 159, 160-1, 163, 169, 331-2, vii, 10-11

(see also Long Distance Transmission)
Power Transmission (Hydraulic), v, 104-8
Power Transmission (pneumatic), i, 26, 27-9
Practice, effects of, xi, 253
Praepositus, Nicolaus, x, 37
Præsepe, star cluster, ii, 336
Pragmatic Philosophy, xvi, 196
Prairie Dogs, xii, 294
Prairie Fires, smoke from, i, 56
Prairies, dominance of grasses on, xiii, 350;
plant societies of, 373-6;
soils of, xiv, 383;
United States, 374, xiv, 373;
windbreaks, i, 333
Prase, iii, 337

Praseodymium, symbol and atomic weight, viii, 383

Prayer, primitive conceptions of, xv, 344-7

Pre-Babylonian Science, xvi, 56-63

Precession, of gyroscopes, v, 336, 337-9, 340, 341, 342

Precession of Equinoxes, ii, 70-1;
Arab work on, 38;
discovery, xvi, 90;
Hipparchus on, ii, 31, 300
Precipitate, defined, viii, 380

Precipitation (atmospheric), annual amount, xiv, 135;
climate determined by, 351-2, 355-6;
measurement, i, 79-82;
mountain effects, xiv, 354-5;
source of terrestrial waters, 134, 151;
various kinds, i, 106-22, 379

Precipitation (electrical), vi, 164, vii, 216, 346-51

Precipitation Treaters, vii, 348-51

Prehistoric Man (see Primitive Man)

Prehistoric Times, before writing, xv, 167, 322-3;
geographical and climate changes since, xiv, 29-30

Prejudice (see Bias)
Preoccupation, of mind, xi, 154-5
Prepotent Inheritance, x, 230
Preservatives, action of, viii, 333;
chemical, 372
Preserving of Foods, viii, 371;
effect on vitamines, x, 263, 266

Pressure, boiling point and, iv, 167-8, 169-70;
critical, 171-3;
melting point and, 153, 162, 163-6;
sense of, xi, 109, 110, 111, 113, 114

(see also Atmospheric Pressure, Gases, Liquids)

Pressure Areas, ordinary movement, i, 237;
physiological effects of alternations, 329-30;
wind and weather attendants, 125, 134-5, 218, 237-8, xiv, 349-50

(see also Highs, Lows)
Pressure Belts, i, 127-9
Pressure Cookers, iv, 171
Pressure Gradients, i, 126, 373;
reversal, 130, 131

Pressure Waves, in alternating currents, vi, 198

Prevailing Westerlies, i, 128, 379, xiv, 345-6, 349

Preventive Medicine, x, 282-317;
history of development of, 15, 99, 133-4, 171-6, 217-18

Prickly Fruits, xiii, 58, 343
Priestley, chemical work, xvi, 120, 177;
oxygen discovery, viii, 34, x, 89, xiv, 65
Priests, of savages, xv, 349-53, 354, 359

Primary Cells, iv, 299, 383, vi, 130, 131-44, vii, 363;
chemical action of, viii, 167

Primary Coils, iv, 383, importance of knowledge of, 9

Primary Colors, iv, 366
Primary Concepts, iv, 14-16
Primary Rocks, viii, 191;
disintegration, 194-5

Primates, iii, 301, 302, xii, 373-4, 375, xvi, 126

Prime Movers, ix, 15, vii, 373;
of future, v, 171-81;
various kinds, vi, 181-2, 351-2
Primitive Man, æsthetic arts of, xv, 296-325;
conditions of life, x, 10, xv, 188-92;
dogs of, xii, 345-6;
language of, xv, 140;
love of decoration in, 252-3;
mind and beliefs, xvi, 42, 43-5, 51, 56;
religion of, xv, 327-59;
sex relations of, 277-8;
tools and weapons of, v, 11, 12-15, xv, 102-10;
types of, 77-102
(see also Cave Men, Savages)
Primrose, leaves, xiii, 88;
petals, 190
Primrose Family, xiii, 203-4
Prince Rupert Drops, viii, 281
Princeton College, founding, xvi, 127
Prince's Island, groundsel in, xiii, 345
Principle of Archimedes, iv, 30, 102-5;
applicable to gases, 107, 126
Pringle, John, x, 104, 155
Print, machines to read, v, 332-5, 384
Printing, v, 300-13;
color, iv, 370-1;
electrotyping, vii, 313-14;
invention of, xv, 179;
invention, results on science, ii, 13, 40, 42, x, 44;
photographic, viii, 173

Printing Presses, development, v, 300-5, 378, 379, 381

Prisms, effect on light, i, 165, ii, 99, 111, 112, iv, 357-9, 365, viii, 301

Prisoners, habit in, xi, 255;
labor of, 275
Privet, leaf arrangement, xiii, 38
Proboscis, of insects, xiii, 126
Proctor, astronomer, ii, 249, 343
Procyon, ii, 297, 319

Prodigality of Nature, in ferns, xiii, 155, 156;
to insure reproduction, 117, 118, 124, 152
Produce Exchanges, weather reports at, i, 252
Professional Men, food requirements, ix, 297
Proficiency, unconsciousness of, xi, 254
Profiteers, and farmers, vii, 220, 221
Prognathic Angle, xv, 44 (fig.)
Prognosis, Hippocrates on, x, 78
Progress, cumulativeness of, xvi, 41;
due to experience of past, ix, 153, xv, 30-1;
due to individuals, xi, 333;
in organic life, xvi, 152;
language and, xv, 68, 145-6;
rhythm in, xvi, 46, 116;
scientific (see Science, progress);
summary of mechanical, v, 376-84;
transportation and, 18
Projectiles, atmospheric resistance, v, 369;
explosives for throwing, viii, 260-1;
flight, i, 312-13;
from aeroplanes, v, 372-3;
handling on battleships, vii, 334;
meteorological corrections, i, 312-13;
sound, i, 193-4;
World War, v, 372
Prometheus, story of, viii, 89
Promontories, formation of, xiv, 256
Pronghorns, xii, 322-3
Proof by Induction, xi, 242
Propane, viii, 210
Propellers, iv, 34;
electric drives, v, 105-6, 153-4;
mechanical and electric drives, vii, 329-30;
most efficient speed, 329;
of early steamboats, v, 189-90;
suction applications of, iv, 127
Proper Motion of Stars, ii, 121-2, 304-5;
determined by spectrum analysis, 119-20;
Eddington on, 344;
Halley's discovery of, 84, 86-7;
in relation to spectral type, 307-9;
origin, 308

Property, inheritance systems, xv, 289-90, 294

Prophylaxis, x, 213, 318 (see Immunity)
Propionic Acid, viii, 220
Proportional, defined, iv, 63
Proprioceptive Senses, xi, 63
Propyl Alcohol, boiling point, viii, 212, 299
Propylene Glycol, boiling point, viii, 299
Prosauria, xii, 182, 183, 203
Prosepny, geological work, xvi, 172-3
Protagoras, on relativity, xvi, 85, 87;
theory of knowledge, 87
Proteases, viii, 357
Protective Coloration, xv, 17-18;
in amphibians, xii, 170;
in birds, 245-6;
in lizards, 204;
in lions and tigers, 359-60;
in rabbits, 287
Protective Devices (electrical), vii, 32-50

Protective Methods in Plants, flower buds, xiii, 45;
leaf-buds, 34;
leaves, against sunlight, 89;
leaves, hairy covering, 104-5;
nettles against animals, 42
Protective Motions, of animals, ix, 21
Proteins, viii, 380;
amount in daily diet, 366-7, ix, 300-1;
amount needed in foods, ix, 281-4, x, 255-6, 278-9;
anaphylaxis from injection of, x, 213, 214, 223;
animal and plant, ix, 278-9, 280, 287;
animal and plant percentages, viii, 348, 349, 351;
antigenic properties of, x, 205;
body heat production by, ix, 309;
body needs of, ix, 33, 34-5, 278, 287-8, x, 255-6, 277-8, xi, 279;
body percentage, viii, 348;
calories in, 361, x, 269;
chemical composition and properties, viii, 351-2, 357, ix, 29, 279, 287;
classification, viii, 352-3;
different kinds, ix, 278-9;
digestion and utilization of, 235, 242, 243, 244, 245, 279-84, x, 204, 270, 277-80, 319, 326, 329, 330, 342;
energy value, ix, 300;
excess of, in food, 283-6;
human, 279, 280, 287;
in blood, 176-7, 181, 183, 184, 194-5;
injections of, effects, x, 204, 213, 214, 223;
injections of, in therapy, 226;
in plants, iii, 344, viii, 348, 349, 350, 351, ix, 278, 280, 287;
in protoplasm, 32-3, 34, 278;
in various foods, viii, 362, 363, 364, 366, ix, 300, xiii, 213;
likeness and differences, ix, 278-9;
making of, by plants, viii, 336, 349, 350, ix, 29, 278, xiii, 95;
metabolism effects, ix, 301-2;
molecular structure, viii, 217-18;
need of, in diet, x, 255-6, 268, 278-9;
nitrogen in, viii, 64-5, 73, 340, x, 270, 277, 342;
plant, ix, 278-9, 280, 287;
plant percentages, viii, 348, 349, 351;
storage of, by body, x, 272;
wool and silk as, viii, 256
Proterozoic Era, iii, 20, 174-8;
plants and animals, 251, 261-2, 262-3, 264-5, 270, 271, 276

Proterozoic Rocks, iii, 174-8
Prothallus, xiii, 157, 158, 160, 162
Protonema, xiii, 156, 162, 163
Protoplasm, x, 228;
basis of life, ix, 13, 17, x, 228, xiii, 74;
body percentage of, ix, 31;
chemical composition and processes, viii, 356, ix, 32-3, 34, xvi, 155;
chlorophyll and, xii, 14;
color in nerve cells, ix, 124;
conditions necessary to, ii, 243;
constitution and functions, ix, 41-3;
control of activities of, 39-40;
differences of, in plants and animals, 278-9;
inactivity when cooled, 306-7;
maintenance and growth, 34-6, 278-84;
making of new, 32, 33, 38-9, 287-8;
motion by, 73;
occurrence and nature, xii, 13;
origin of, xiii, 300;
salts in relation to, ix, 32, 174;
signs of life, 13-17;
studies of, xvi, 166;
wastage of, in body, ix, 34, 282-3;
water in, effects on metabolism, 37-8
Protopterus (fish), xii, 166
Prototheria, xii, 271, 272-4
Protozoa, iii, 259, 263, 265-6, xii, 25, 26;
disease-producing, x, 199, 200, 204;
in plankton, xvi, 147;
origin of, xii, 12;
reproduction in, 26
Prout's Hypothesis, viii, 177, 187
Prunes, as antiscorbutic, x, 266;
eating of, ix, 251
Prussia, vaccination in, x, 103
Pruth River, xiv, 185
Psuchrainometer, i, 319, 379
Psyche, xvi, 17
Psychiatry, x, 356, 357
Psychic States, motor character, xi, 58-9, 61
Psychor Analysis, x, 243, 363-5
Psychology, Volume xi
Psychology, complexity of science of, x, 368;
concrete science, xvi, 42;
daily applications, 17-19;
defined, 37, xi, 10-14;
field of applied, 9-10, 367;
medicine and, x, 369;
origin of name, xvi, 17
Psycho-neuroses, x, 359-60
Psychoses, of adolescence, x, 236-7
Psychrometers, i, 78-9, 379
Pteranodons, iii, 294
Pteridophytes, iii, 251, 252, 253, 256
Pteridosperms, iii, 251, 252, 254-5
Pterodactyls, xii, 202, 203 (fig.)
Pteropoda, xii, 18, 19
Pterosauria, xii, 182, 202
Ptolemaic System, ii, 10, 34-6, xvi, 93;
Bacon's criticisms, 101;
Copernicus and, ii, 49;
dissatisfaction with, 40, 42;
Galileo and, 54;
Regiomontanus and, 40;
persistence, 45
Ptolemy, ii, 32;
Almagest, 10, 33-6;
Aristotle and, 42;
conception of moving bodies, 63;
debt to earlier astronomers, 29;
ideas of cosmos, 367;
remarks on geography of, xiv, 3;
works of, xvi, 93-4
Ptomaines, viii, 215
Ptyalin, ix, 230, 235-6
Puberty, mental diseases following, x, 236-7;
need of health instruction at, 283
Public Halls, ventilation methods, ix, 269
Public Health, campaign for, x, 171, 172;
science of, viii, 317-33
Public Health Service, U. S., x, 190-1
Public Lands, (U. S.), xiv, 384
Public Opinion, power of, xv, 374-5, 380
Public Speakers, and audiences, xi, 216;
pitch of voice in, iv, 232
Puccini, reference to, xv, 297
Pudding-stone, sedimentary rock, xiv, 18
Puddled Clay, xiv, 137
Puddling Process, invention, v, 316-17
Pueblo Pottery, xv, 249 (fig.)
Puerperal Fever, x, 114-15
Puff Adder, xii, 231-2
Puffballs, fungous, xiii, 71
Puffins, xii, 264-5
Puget Sound, harbors of, xiv, 268;
salmon in, xii, 157
Pugnacity, derivation of word, xi, 43-4;
instinct of, 56
Pulleys, v, 33-5;
action of, like levers, iv, 89;
friction in, 93
Pull-out Loads, of motors, vi, 260
Pulmonary Artery, ix, 199, 201 (fig.);
capillaries of, 254;
elasticity of, 210
Pulmonary Vein, ix, 199, 201 (fig.);
blood in, 260
Pulmonates, xii, 68-71
Pulp, in paper-making, v, 291-5
Pulse, ix, 211;
former ideas of, x, 62, 63;
Galileo's measurement, v, 64-5;
rate of, x, 334
Pulsilogia, Galileo's, v, 65
Pumas, xii, 363-4

Pumice, from Krakatoa eruption, iii, 101, xiv, 325;
in ocean, iii, 55, xiv, 285-6
Pumpelly, climate studies, xiv, 29, 361;
on loess accumulations, 73-5
Pumpkin, xiii, 54-5, 223
Pumps, centrifugal, vi, 363;
chain, iv, 26;
electric and automatic, vi, 99-100, vii, 86-7;
for deep wells, v, 114-15;
force, 113-14;
suction, 112-13;
reciprocating, motors used, vi, 234;
suction, iv, 26-7, 126
Punching Machines, chisel form, v, 46;
motors used, vi, 235
Pupil, of eye, ix, 109, 110 (fig.);
dilation of, in fear, 166;
size changed by smooth muscle, 162
Purbach of Vienna, ii, 40
Purchase, marriage by, xv, 283-5
Pure Breeds, in animal breeding, ix, 337;
from crosses, 335, 336
Pure Food Law, viii, 370
Puritanism, suppression of emotions, xi, 140
Purmann, Matthaeus, x, 78
Purple Dyes, sources of, xii, 68, 72
Purple Light, of sunsets, i, 167, 379-80
Purple Loosestrife, xiii, 140-1
Purpose, motor character, xi, 61 (see Will)
Purslane, xiii, 15
Pus, formation of, ix, 186-7;
former conception of, x, 39-40, 41, 43;
modern attitude towards, 145, 147
Pus Pockets, ix, 187, 188

Pus-producing Germs, ix, 186-8, x, 195, xiii, 71;
infections by, x, 198, 207, 221;
vaccination against, 218
Putrefaction, cause, xvi, 143;
intestinal, ix, 249-50
Pycraft, Prof., on chameleons, xii, 209-10
Pyemia, x, 198
Pygmies of Africa, xv, 38-9
Pyorrhea, of gums, x, 202, 219, 222
Pyramids of Egypt, ii, 24, xv, 269-71;
civilization exhibited, xvi, 66-7, 71;
orientation, ii, 26;
rocks used in, iii, 235;
weathering of, xiv, 78
Pyrene Extinguisher, vi, 101

Pyrenees Mts., as barrier between Spain and France, xiv, 239-40;
geranium of, xiii, 136;
geological history, iii, 235, 236, 240;
recent formation, xiv, 235
Pyrheliometer, i, 88, 380
Pyridine, viii, 240, 253
Pyrite, iii, 335-6;
gold in, 366
(see also Iron Pyrites)
Pyrogallol, viii, 288
Pyrosoma, xii, 19-20
Pyroxene, composition of, viii, 193
Pyroxene Group, iii, 336
Psycho-Analysis, x, 243, 363-5

Pythagoras, conception of universe, ii, 10, 42-3, xvi, 80, 81-2;
mathematics of, 79-81;
medical work of, x, 17-18
Pythagorean Theory, xvi, 81-2
Pythonomorpha, xii, 182, 202-3
Pythons, xii, 213-15
Qobar, i, 380
Quacks, Barton on, x, 76, 367, 374-5;
cures of, vii, 240-1
Quadruplex Telegraphy, vii, 112, 117
Quagga, xii, 308
Quahogs, xii, 66-7
Quails, xii, 261
Qualitative Analysis, viii, 285-91
Quantitative Analysis, viii, 285, 291-5
Quantum Dynamic Theory, xvi, 134-5
Quarrying, in ancient Egypt, xvi, 67-8;
joints in, xiv, 128-9
Quart, compared with liter, viii, 28
Quartz, iii, 336-8;
fused, manufacture and uses, vii, 311-12;
gangue mineral, viii, 199;
gold found with, iii, 366, 367;
in granite, 27, 308;
in iron ore, 356;
in soils, 27, 28;
insolubility, viii, 112
Quartzite, iii, 381;
origin, 169, 189
Quaternary Period, iii, 20, 236-48;
appearance of man, 302, 303, xv, 72;
differentiation of races in, 95;
divisions of, 71;
Ice Age (see Ice Age)
Quaternion Analysis, invention, ii, 72
Quatrefages, morphology studies, xvi, 140-1
Quebec, harbor of, xiv, 270;
plateau of, 221, 236
Quebec Bridge, construction, v, 100-1
Queen Anne's Lace Plant, xiii, 201
Queensland, barramunda of, xii, 165
Queensland Hemp, xiii, 244
Questions, suggestion by form of, xi, 308-10
Quetelet, xvi, 153
Quicklime, iii, 373, viii, 149-50

Quickness, in different types of men, xi, 156-9

Quicksand, excavating through, v, 115-18, 123
Quicksilver (see Mercury)
Quinces, origin, xiii, 226
Quinine, an alkaloid, viii, 240;
from tropical forests, xiv, 383;
history and production, xiii, 250-2;
importance of discovery, 9;
sulphate of, iv, 356, 379;
use in malaria, x, 154-5, 158, 381
Quipus, xv, 165 (fig.), 166
Ra, Egyptian sun-god, ii, 24;
horns of, xii, 326
Rabbits, xii, 286-8;
direction perception by, ix, 117;
embryological development, xv, 55;
fear in, xi, 136;
heart of, x, 332;
nest-making by, xi, 56;
protective coloration in, xv, 17, 18;
rate of increase and destructiveness, 20
Rabelais, François, x, 45
Rabies, germ of, x, 200;
Pasteur's cure of, 141, 142-3
Raccoon Creek, Ohio, xiv, 185
Raceme, flower form, xiii, 50
Racemic Acid, Pasteur's studies of, x, 137
Racers (snakes), xii, 218, 219, 220
Races of Mankind, xv, 32-4;
brain and skull, differences, 41-3, 62;
contact of inferior, xvi, 50;
characteristic diseases, xv, 47-52;
differences in, due to proteins, ix, 279;
European, xvi, 48-50;
extinction of, xv, 98-9;
intermixture of, 32, 35-6;
language and, 159;
mental characteristics, 36;
physical characteristics, 36-47;
separate origin theory, 69-70;
subdivisions of, xiii, 173;
type characters, 34-6;
vanished and weak, xvi, 64
Races, Tidal, xiv, 294
Race Type, xv, 34-5
Racing Cars, speed, v, 214
Radial Velocities of Stars, ii, 120, 122;
of nearest stars, 319;
of star clusters, 337, 339;
photographic study, 137, 158-9
Radiant Energy, iv, 322, 366, ix, 114-15;
of sun and stars, ii, 170, 383-4, iv, 181-2, 194

(see also Radiation)
Radiant Matter, iv, 54-5
Radiation, heat, iv, 180-4, 366;
light production by various kinds, of, 378-80;
penetrating, i, 143-4, 146, 379;
terrestrial, volcanic dust effects, 59;
therapeutical uses of, x, 383
Radiation Emanation, vi, 269-70

Radiative Equilibrium of sun and stars, ii, 382, 383-4

Radiators, heat of, iv, 186, 187
Radicals, Chemical, viii, 93, 380;
method of expressing, xvi, 160-1;
valences of, viii, 94
(see also Groups)
Radioactive Substances, viii, 184-9;
emanations of, i, 143, 330;
fluorescence produced by, iv, 380;
helium produced by, xvi, 194;
in nature, i, 143, xvi, 193;
ionization by, i, 143-4
Radioactivity, viii, 184-9, 307;
climatic effects, i, 211;
discovery of, iv, 55, xvi, 165, 193;
explained by electron theory, iv, 23;
of meteorites, ii, 292;
light theory, iv, 50;
physical phenomena of, viii, 307
Radio Communication, vii, 258-98
(see also Wireless)
Radio Compass, i, 191

Radio Control, of aeroplanes and ships, vii, 283-4

Radio Corporation of America, vii, 274-5
Radio Generators, vii, 273-8;
in aeroplanes, 282-3
Radiographs, X-ray, vii, 253-4, x, 185-6
Radiolarians, xii, 17-18;
in plankton, xvi, 147

Radio Stations, aeronautical services, i, 292;
distress signal system, vii, 284;
intercommunication, 261;
remote control from, 283-4;
weather reporting, i, 281, 282
Radio Theory, vii, 285-98
Radiotherapy, x, 383-4

Radio Waves, conversion by vacuum tubes, vi, 339-41;
damped and undamped, vii, 273-4, 289-90;
generation and detection, iv, 314-15, vi, 163, 215, vii, 273-8, 286-91, 293-8;
generation in aeroplanes, 282-3;
length, iv, 315, vi, 269, vii, 260;
length, by what determined, 266;
lengths used, 272, 274, 275;
measurement of length and frequency, 291-5;
measured in meters, 272;
remote control by, 283-4;
transmission, 261, 263-73, 278-80
(see also Radio Communication);
vibrations in æther, vi, 119, 163, vii, 250
Radish, xiii, 197, 223
Radium, viii, 184-5, 186;
atomic weight and symbol, 383;
discovery and occurrence, xvi, 193;
disintegration into niton, viii, 185;
emanation (see Niton);
energy from disintegration, viii, 186-7;
fluorescence and luminosity from, iv, 380;
increase, xvi, 194;
in soil, i, 143;
therapeutic uses of, x, 383-4
Radium Compounds, viii, 184
Radium Watch Dials, iv, 380
Radius Vector, ii, 51
Raffia, origin and product, xiii, 244
Raffles, Sir Stanford, xiii, 363
Rafflesia Arnoldii, xiii, 364;
illustration, 352
Rafts, xv, 264-5
Rage, emotion of, xi, 138, 139
Rags, paper from, v, 290-1, 292
Ragweed, pollen of, xiii, 118
Rahbeg, Arabia, charting of harbor, i, 47
Rahu, Chinese dragon, ii, 209
Railroads, air brakes on, iv, 129, v, 130-2;
block signal systems, vii, 355-9;
coal using, v, 172;
early, 207, 208, 377, 378-9;
effects on rivers and water power, xiv, 31, 191;
electrification (see Electrification of Railroad);
in tropical regions, xiii, 359;
present inadequacy, vii, 194-5;
snow removal, i, 117;
weather and climate problems, 267-8

Railroad Terminals, electrification, vi, 162, vii, 181-2, 193, 197-8

Railroad Ties, walking on, ix, 89
Railroad Tracks, expansion by heat, iv, 134;
outer rail on curves, 73;
pneumatic tamping, v, 135;
reduction of friction, 206;
sound transmission by, iv, 199;
traction of, v, 207
Rails (birds), xii, 261-2
Rails (Railroad), manufacture of, v, 322-3
Rain, i, 108-9;
artificial production, 332, 333-4, 336-40, 345;

"blood showers," 55;
business effects, 264, 265;
dust depositing by, 55;
explanation, 93;
formation of drops, 112-13;
formation in hot afternoon storms, vii, 217;
from cloudless, sky, 119;
gray suit sets and, 166;
large drops in thunderstorms, vii, 215-17;
low pressure areas and, i, 237;
no region without, 210;
rainbow predictions, 177;
red, 358;
rock-weathering by, xiv, 39, 41-2, 49, 62, 63, 77, 105-6;
salt deposited, by, i, 59-60;
sounds as prognostics of, 187;
yellow, 61
(see also Raindrops, Rainfall)
Rain Balls, i, 104, 380
Rainbow, i, 175-7, 380, iv, 374-6;
colors of, ix, 115;
Keats on, i, 346

Rain Clouds (see Nimbus, Cumulo-Nimbus Clouds)

Raindrops, formation, i, 112-13;
rainbows due to, 175, 176;
size, 113-14;
speed of fall, 113, 114
Rainey, George, xvi, 145
Rainfall, i, 380;
ascending air currents and, xiv, 354-6;
changes in historic period, 362;
climate determined by, 351-2, 355-6;
corn-crops and, i, 247, 248;
distribution and intensity, 109-12, 208;
economic importance, 263;
examples of excessive, 109-11, 111-12;
forests dependent on, xiii, 367, 372, 373-4, 376, xiv, 377-8, 379;
in desert regions, xiii, 377, 380;
in tropical forests, 358, 360;
measurement, i, 79-82;
measurements, ancient, i, 68;
mountains and, 111, xiv, 354-6;
plant types determined by, xiii, 357-8, xiv, 369;
soil elements affected by, 68-9;
solar radiation and, ii, 187-8;
sun-spots and, 186;
statistics, importance of, i, 110-11;
water in inch of, 109;
water table dependent on, xiv, 136
(see also Precipitation)
Rainfall Charts, i, 206
Rain Forests, xiii, 358-66, 372, xiv, 368-9
Rain Gauges, i, 68-9;
kinds and uses, 80-2, 380;
on Mt. Waialeale, 112
Rain Gods, Australian, xv, 195
Rainier, Mount, xiv, 225;
beauty of, 100-1, 315;
glaciers of, iii, 60-1;
snow honeycombs, i, 117;
vapors of, xiv, 313, 314;
volcanic origin, iii, 106, 226
Rain Insurance, i, 270
Rain-making (see Rain, artificial production)
Rains, curious, i, 355-9;
of toads, xii, 177
Rainstorms, gathering of, viii, 304;
water in, 109-10
Rain Tree, i, 349-52, 380
Rain Water, nitrogen compounds in, i, 13
Rainy Regions, factors determining, i, 111

Rainy Weather, splitting of tomatoes in, xiii, 94

Raisins, eating of, ix, 251

Rakers, automatic, v, 246, 247, 379

Raleigh, Sir Walter, introduction of potato by, xiii, 218

Rameses, monument, xvi, 67;
sacrifice made by, xv, 347
Ramie, cellulose composition, viii, 254;
origin and product, xiii, 244
Rams, horns of, xii, 325-6

Ramsay, Sir William, discovery of elements, i, 12;
discovery of argon, viii, 67;
helium discovery, xvi, 194
Ranches, cattle, xiv, 383-4
Range Finders, principle, xi, 179-80
Ranges, electric, vii, 88-9
Rankin, Angus, quoted, i, 158
Raoulia Cushions, xiii, 379-80
Raphael, anatomy advanced by, x, 51-2
Rapids, in new and old regions, xiv, 48, 49
Rapid Sand Filters, viii, 320
Rare Earths, viii, 182
Raspberries, origin, xiii, 226
Rate, technically defined, iv, 383

Ratings, of electrical machines, vi, 192-4, 212, 317

Rationalizations, xi, 244-5
Ratite Birds, xii, 243, 249
Rats, xii, 289-91;
bubonic plague and, x, 163, 165-7;
cannibalism of, ix, 280-1;
dangerousness of, 12, 285-6;
sleeping sickness organism in, x, 168;
snakes and, xii, 219, 220, 222;
war against, x, 171
Rattan Cane, xiii, 244
Rattan Palm, xiii, 27, 361, xiv, 368
Rattlesnakes, xii, 234-8;
prairie dogs and, 227;
tongue of, 212
Ravenna, formerly on coast, xiv, 53
Raw materials of Plant Life, xiii, 79;
Sources of, 80, 81
Ray, natural history work, xvi, 116, 126
Ray Flowers, xiii, 206

Rayleigh, Lord, discovery of argon, i, 12, viii, 67;
light theory, xvi, 137-8;
on ultra-violet light, i, 16;
sound studies of, iv, 52
Rays (fish), xii, 148-50;
eyes of, 138
Rays, of flowers, xiii, 44, (fig.), 49;
of light and electricity, iv, 383
Razor Fish, xii, 59
Reactance, condenser, vi, 171;
current-limiting, vii, 49;
inductive, vi, 170;
in alternating currents, 170, 172;
in induction motors, 248;
in oscillating circuits, vii, 289

Reaction, principle of equal, v, 143-4 (see Action and Reaction)

Reactions (physical) outgoing and withdrawing, xi, 54-6

(see also Motor Responses)
Reaction Types and Times, xi, 152-9
Reactors, current-limiting, vii, 49
Read, Commander, on aeroplane safety, i, 50
Reading Glasses, ix, 111
Reading Machines, v, 332-5
Reagent, defined, viii, 381
Reality, Aristotle on, xvi, 88;
in pragmatic philosophy, 196
Reaping Machines, v, 240, 244-9, 379
Reason, Reasoning, xi, 237-46;
in man and animals, xv, 65-6, 67-8;
in sleep, xi, 286, 287;
instinctive, 46, 47;
meanings of, 233-4, 237-9
Rèaumur, René, A. F. de, x, 88, xvi, 174;
thermometer, scale of, iv, 136, 137
Rebus, game of, xv, 168-9
Receivers, telephone, vii, 94, 96-7
Recency, in associations, xi, 204-5
Receptacle (botanical), xiii, 153
Reception Halls, lighting, vii, 70-1
Receptor Neurones, xi, 21, 22, 26, 27, 30;
in embryo, 34, 35

Receptor Organs, of various senses, xi, 63, 116-17

Recessional Moraines, iii, 67
Recession of Spring Heads, xiv, 176
Recessives, in crosses, x, 231
Reciprocal Accumulation, vi, 298
Reciprocal Innervation, xi, 86

Reciprocating Engines, compared with turbines, v, 152-3;
control, 153;
disadvantages, 148;
waste of heat energy, 155
Recoloration (see Afterglow)
Recording Meters, vii, 177-8
Recreation, psychology of, xi, 269-70
Rectifiers, mineral contact, vii, 268-9;
mercury arc, vi, 331, 333-9;
vacuum tube, 339-41
Rectilinear Coordinates, iv, 16
Recurrence, Weather, i, 362-3, 380
Recurrent Images, xi, 221
Red, complementary color of, iv, 367;
effects of blood pressure, xi, 63;
heat colors, iv, 361;
of sunset and rise, i, 166, 168;
penetration of ocean by, xii, 22;
primary color, iv, 366;
seeing of, in color-blindness, ix, 116;
stimulating effects, vi, 274;
vibration rate, ix, 115;
wave lengths, i, 165, iv, 360, 365
Red Beds, iii, 202, 204, 208
Red Cedar, spread, xiii, 340

Red Clay, on sea floor, iii, 54, xiv, 285, 286

Red Coral, xii, 43
Red Corpuscles, ix, 181-4, 275;
blood transfusion in relation to, x, 338;
carbon monoxide effects on, viii, 50-1;
held by capillary walls, ix, 194;
oxygen-carrying by, ix, 182-3, 258-9, x, 338-9;
reduced in anemia, 337
Red Cross, Pringle's idea, x, 104
Red Crust Polyzoans, xii, 47
Redfield, W. C., i, 215
Red Fire, viii, 301
Red Flash, of sun, i, 171
Red Hot, temperature of, iv, 361
Redi, Francesco, xvi, 114
Red Lead, viii, 162
Red Light, photographic uses, viii, 171
Red Marrow, ix, 183
Red Pepper, source, xiii, 221
Red Race, xv, 32, 37;
diseases of, 51;
separate origin theory, 70
Red Rain, i, 358
Red River of the North, xiv, 158, 201
Red Sea, in Great Rift Valley, xiv, 117-18;
origin of color, xvi, 147;
salt in, viii, 139, xiv, 296-7;
sharks of, xii, 145
Red Snow, i, 358
Red Test, of kidneys, x, 378
Red Thread (worm), xii, 54
Reduction (chemical), viii, 381
Redwood Forests, fog drip, i, 351
Redwoods, former distribution, xiii, 320;
of California, xiv, 374
Reed, Dr. Walter, x, 160, 162, 200
Reed Instruments, iv, 284-5
Reed Boat, xv, 264 (fig.)
Reefs, oceanic, defined, xiv, 286;
of seaweed deposits, iii, 250, 251
(see also Coral Reefs)
Refining of Metals, viii, 272
(see also Electro-Refining)
Reflection of Light, iv, 324-5, 330-1;
by mirrors, 335-7;
total, 373-4
Reflectors (heat), iv, 182

Reflex Actions, ix, 185-6, 258, xi, 20, 26-7, 62-3, xv, 65;
development in embryo, xi, 35-6;
grasping reflex, 40-3;
hypnotic suggestion of, 317;
in glands and smooth muscle, ix, 163;
in infants, 349;
in vasomotor system, 311;
in sleep, xi, 26-7, 286;
instincts as, 48;
law of final common path, 22;
mind as sum of, 23-5;
shivering, ix, 309-10;
some special, 155-9, 163, 168-72

(see also Chain Reflex, Circular Reflex, Conditioned Reflex)

Reflex Arc, x, 20-8;
time factors, 154

Refracting Telescopes, ii, 96-101, 103-4, 108, 202

Refraction of Light, iv, 325, 326-9, 330, 331, 373-4;
astronomical, i, 167, 380;
by lenses, iv, 337-9;
index of, in chemical analysis, viii, 310;
Newton and Huygens' studies, xvi, 119;
terrestrial, i, 171, 380
Refraction of Sound, iv, 286-7
Refractories, furnace, vii, 306-8

Refractory Phase, of nervous excitation, xi, 21

Refrigerating Machines, v, 346-7, 350, 351-8, 380, vii, 85-6, viii, 59

Refrigeration, ammonia system, iv, 187-8;
battleship system, 331-2;
domestic, 85, 86;
electric, 85, 229-30;
evaporation methods, iv, 174, 187;
expansion and brine methods, vii, 85-6, 328;
freezing mixtures and solutions, iv, 175; ice, iv, 178;
ice, objections to, vii, 230;
liquid air, i, 30, 31-2;
salt used in, viii, 140
(see also Refrigerating Machines)
Refrigerator Cars, v, 346-7
Regelation, iv, 165-6, 383
Regeneration, power of, xii, 170
Regenerative Brakes, vii, 200
Regiomontanus, ii, 13, 40-1
Regnault's Constant, iv, 142
Regular Coasts, xiv, 250-2, 256, 262;
unfavorable to commerce, 265
Regulators, Induction, vi, 328-9, 346
Regulus (star), ii, 295

Rehabilitation, of World War disabled, x, 189-91

Rehoboam, wives of, xv, 289
Reign of Algæ, xiii, 314, 323
Reincarnation, belief in, xv, 333, 334
Reindeer, xii, 319-20;
horns of, 316;
in glacial period, xiv, 376;
in Cro-Magnon art, xv, 114;
relics of, in Spain, 100 (fig.)
Reindeer Moss, xii, 320
Reinhold, astronomical tables, ii, 44
Reis, telephone of, vii, 92

Rejuvenation (geological), definition, iii, 36, 381;
examples, 219, 230, 231, 232-3;
of folded areas, xiv, 96-8
(see also Elevation)
Reka River, xiv, 150
Relapsing Fever, diagnosis of, x, 216
Relative Time, Newton on, iv, 15
Relative Wind, i, 289, 299, 380
Relativity, doctrine of, iv, 16-18;
Einstein theory, ii, 80-2, xvi, 196-8;
of knowledge and perception, 85, 87, 195-6;
of motion, 12, 85
Relaxation, xi, 339-40, 371-2;
after meals, 374-5
Relay Circuits, vii, 39-48
Relay Regulators, vii, 148-50

Relays, in telegraph lines, iv, 293-4, vii, 110, 374

Relief Features, making and leveling of, xiv, 80;
of new and old areas, iii, 33, 34, 34-5, xiv, 47-9;
of sea bottom, iii, 52, xiv, 286-7;
orders of magnitude, 27

Relief Models, vertical exaggeration of, xiv, 9-10

Religion, Religions, Babylonian and Assyrian influences, xvi, 51-2;
beginnings and development of, xv, 326-59, xvi, 44;
development of, at cattle-raising stage, xv, 199;
fear and, 185;
fire in, 234;
marriage and, 291, 292-3;
meanings of, 326;
medicine and, x, 12, 16, 34, 242-3;
morality and, xv, 355-7, xvi, 43-4, 45, 48;
psychological factors, xi, 130, 151, 204;
science and, iv, 27-8, xvi, 42, 44-5;
similarities in, 43;
universality of instinct, 43, 47
Religious Fanatics, exaltation of, xi, 120;
hysteria of, x, 360
Religious Words, from Hebrew, xv, 161
Remedies, quack, vii, 240-1, x, 76, 367;
specific, 49-50, 75
Remembering, process of, xi, 209 (see Memory)
Remington Typewriter, v, 313, 381
Remora, dorsal fin of, xii, 133;
used in catching turtles, 139-40
Remote Control, vi, 99-101;
by radio waves, vii, 283-4;
in power plants, vi, 360
Renaissance, medicine of, x, 43-60;
science in, iv, 28, ii, 11-12, 12-13, 42
Rennin, enzyme, ix, 235
Repetition, psychological effects, xi, 21-2;
in advertising, 348;
in learning, 214-15
Repletion, sensation of, ix, 91
Repression, of ideas, x, 355-6, 361, 364, 365
(see also Suppression)
Reproach, sentiment of, xi, 149
Reproduction (organic), x, 228;
cells in, ix, 43, 324-5, 332-3, xv, 54, xvi, 156, 157-8;
germ cells in, x, 232;
in primitive animals, xii, 26, 31, 34, 53-4, 60;
rapidity of, in plants and animals, xv, 19-21

Reproduction of Plants, xiii, 43-6, 48-53, 116-67;
transitional form, 309, 316;
without mating, 165-7, 182-3, 215, 217-18
Reproductive Instinct, xi, 56

Reproductive Tissues, cell development in, ix, 48, 287

Reptiles, xii, 182-238;
age of, iii, 20, 21, 286, 292-3, xv, 71;
birds and, iii, 295, 296, xii, 239;
classification place, iii, 260;
egg-laying of, xv, 275;
evolution of, iii, 283, 285-6;
first appearance, xv, 71;
mammals and, xii, 271;

Mesozoic, iii, 286-95, xii, 183, 188, 194-5, 202-3;
origin of, 168;
temperature variations, i, 317;
tracks preserved in rocks, iii, 16
Repugnance, emotional, xi, 275
Repulsion, instinct of, xi, 55
(see also Disgust)
Réseau, i, 221, 380
Réseau Mondial, i, 220, 380
Reservoirs, puddled-clay bottoms, xiv, 137

Residual Magnetism and Voltage, vi, 191, vii, 372

Residual Soils, iii, 26-8, xiv, 68, 145

Residue (chemical), viii, 381

Resignation, as intellectualized reproach, xi, 149

Resinous Electricity, iv, 258, vi, 12
Resins, electrical conductivity, iv, 259;
electrification of, 257

Resistance, electrical, iv, 281-3, vi, 74-9, vii, 374-5;
in dynamo armatures, vi, 185-6;
in electric cells, 135-7;
in electric wires, 79-80;
in magnetic circuit, 93-4;
in wireless circuits, vii, 286, 287, 290, 296, 297, 298;
of various wires, vi, 77, vii, 378-80, 384;
Ohmic, vii, 373;
reduced by liquid air, i, 32;
unit (see Ohms);
variations with temperature, iv, 301
Resistance, Heat, vii, 337

Resistance (mechanical), relation to force, iv, 11, 90, 92

Resistance Coils, vii, 364
Resistance Furnaces, vii, 303-4
Resolution, and will, xi, 259-60
Resolution of Forces, iv, 76-7
Resonance, iv, 225-6;
in sound, 226-32;
in wireless currents, vii, 267, 289-90
Resorcinol, viii, 238
Respiration, chemistry of, viii, 36, 49-50;
discovery of physiology of, x, 29, 88-9;
of fishes, xii, 135;
of insects, 103;
of chelonian reptiles, 187;
processes and disorders of, x, 338-42
(see also Breathing)
Respiration Calorimeter, viii, 361, 367
Respiratory Center, ix, 257;
control of, 264-5, 266

Respiratory Diseases, susceptibility to, xv, 51

Respiratory Quotient, x, 270

Respiratory System, laughter by, xi, 355, 356-7

Rest, as cure for fatigue, x, 247-8;
efficiency and, xi, 363;
necessity of, time used in, ix, 80;
need of, in all things, xi, 21;
nervous fatigue and, ix, 137-8
(see also Relaxation)
Resting Arrow Argument, xvi, 85
Resting Metabolism (see Basic Metabolism)
Resultant, of forces, iv, 76, 99
Retail Sales, and weather, i, 264
Retaliation, Law of, xv, 371

Retina, of eye, iv, 346-7, ix, 109, 110 (fig.), xi, 30, 62, 84, 89-97;
color perception by, ix, 116-17
Retrospect, time lengths in, xi, 194
Retting Process, xiii, 239, 241-2, 243
Revenge, sentiment of, xi, 150
Reverberatory Furnace, v, 316-17
Reverdin, thyroid studies, x, 349
Reverence, sentiment of, xi, 147-8
Reversed Faults, xiv, 114
Revival of Learning (see Renaissance)
Revolution of Earth, ii, 43;
known to Aristarchus, 28;
orbit, changes in eccentricity, 73, 74-5;
orbit, measurement, 121, 162, 263;
orbit, speed in, 91-2, 163;
proved by aberration orbits of stars, 92;
year measured by, iv, 15

Revolutionary War, Bushnell's submarine, v, 197;
muskets in, 361;
surgeons of, x, 104
Revolutions, geological, xiv, 29
Revolving Turret, patented by Timby, v, 380
Rex Begonia, reproduction, xiii, 165-6
Reymond, Emil du Bois, x, 126-7
Reynolds, Osborne, xvi, 132
Rhazes, Arab writer, x, 32
Rheas, xii, 243, 249
Rheostat, iv, 383, vii, 375;
invention, vi, 23
Rheticus, friend of Copernicus, ii, 43
Rheumatism, Rheumatic Fever, x, 223-4;
acute, ix, 187-8;
barometric effects, i, 329;
germ of, x, 195, 221, 223;
leaking heart valves from, ix, 207;
lightning cures, i, 153;
salicylates in, x, 381;
uric acid and, 343

Rhine River, changes in course and connections, xiv, 185-6;
channel of, 87 (map), 117, 167;
falls at Schaffhausen, 132-3;
varied course, 155
Rhine Valley, xiv, 87 (map), 90, 117, 185-6;
wine industries of, viii, 249
Rhinoceros, xii, 304-6;
ancient remains, iii, 16, 303;
formerly in Europe, xv, 76, 79, 92;
Merck's, 100 (fig.), xii, 305 (fig.), 306
Rhizoids, xiii, 156, 157, 158
Rhodes, ancient importance, xiv, 281-2
Rhodesia, climate of, xiv, 224
Rhodium, viii, 173;
symbol and atomic weight, 383

Rhododendrons, difficulty of obtaining, xiii, 289;
in heath family, 202;
in southern forests, 367;
seed, 344
Rhodora, flower, xiii, 202
Rhubarb, origin, xiii, 223;
oxalic acid in, viii, 222
Rhynchocephalia, xii, 183
Rhythm, idea of, in man, xv, 251, 310;
In human organism, xi, 281;
in learning, 214;
in scientific progress, xvi, 46, 116
Ria Coasts, xiv, 257-8
Rib Cage, ix, 63, 65 (fig.)
Ribs, of body, ix, 63 (fig.), 65;
connections with breastbone, ix, 71
Rice, ancestral home, xiii, 182, 221;
calories in, ix, 299;
eating of, in relation to stature, xiii, 172;
food value, viii, 364;
fruit for seed dispersal, xiii, 54;
history and uses, xiii, 213-14;
importance, 10, 211;
in grass family, 179;
origin, xiv, 382;
starch from, viii, 243;
transplanting, in Java (illus.), xiii, 208;
vitamines, in hulls of, viii, 369, ix, 35-6, x, 258, 259, 260

Rice Paper, source, xiii, 214
Richer, astronomer, ii, 59, 69
Richet, anaphylaxis studies, x, 212-13
Richter, J. B., chemical work, xvi, 160
Rickets, x, 264-5, 314
Rifles, xv, 218-19;
improvements in, v, 362, 379;
machine gun types, 366-8;
standardization, 50
Rift Valleys, xiv, 117-21, 123
Rigg's Disease, x, 315-16
Right, original meaning, xi, 190
Right Ascension, ii, 299, 300, 305
Right-Hand Rule, vi, 55, 89-90
Rights, grasping instinct and, xi, 44
Rime, i, 108, 380;
formation, 121-2
Ringhals, xii, 227
Ring Hypothesis (see Nebular Hypothesis)
Ring Spinning Machine, v, 273, 276, 378

Ring Structure (molecules), viii, 233, 240, 381

Rio de Janeiro, Corcovado peak, xiv, 112;
harbor of, 268
Rio Negro, connections of, xiv, 187
Rises, ocean, xiv, 286, 288, 290
Ritchey, astronomer, ii, 107-8, 148, 333, 336
River Beds, tunneling through, v, 121-4
River Man, iii, 302

Rivers, alterations in courses (historical), xiv, 183-6;
ancient veneration of, v, 75;
annual discharge of, xiv, 135;
antecedent, 164-70;
base-level of, 40, 49;
"beheaded," 182;
channels, gorges, and valleys, iii, 40-4, xiv, 49-52, 167-8;
classification of, 153-5;
connection of systems, 186-7;
consequent, 157;
courses changed by earthquakes, xiv, 335;
courses determined by rock structure, 43-4, 131-2, 160, 175, 187-8;
deltas (see Deltas);
development of, 155-88;
erosive work of, iii, 30-44, xiv, 39-40, 49-54, 158-63, 198, 233;
forest regulation of, xiii, 372, xiv, 379;
harbors in mouths, 270-1;
headward extension, iii, 38-9, xiv, 175-6;
homogeneous and heterogeneous, 154-5;
importance, xv, 129;
importance, by what determined, xiv, 189;
importance, historical and industrial, 31, 190-7;
in clayey country, 137;
in new and old areas, iii, 33-4, xiv, 48, 49, 155-63;
in regions of subsidence, iii, 37, xiv, 40, 163-4;
in rejuvenated regions, iii, 36, 232-3, xiv, 40, 163, 164-70;
longitudinal and transverse, 153-4;
marine and continental, 153;
metaphorical names of parts, xv, 158;
mineral matter in, viii, 196, xiv, 206;
obsequent, 160;
"piracy," 177-83, iii, 38-9;
potholes in beds, 39-40;
power of currents, 30-1, xiv, 39-40, 198;
power utilization, 5, 75-93;
recession of spring heads, xiv, 176;
sedimentary deposits of, xv, 84;
sediment carried by, iii, 31-3, xiv, 52-3, 161;
seed dispersal by, xiii, 346;
sewage systems, viii, 325;
sources of water, xiv, 182-3;
subsequent, 159;
superimposed, iii, 39, 137, 233-4, xiv, 170-4;
topography produced by, 49-54;
trunk and branch, 153;
underground, iii, 116, xiv, 149-50;
use in industry, vi, 352, 353, 361, 366-7;
water supply from, xiv, 140, 141
(see also Drainage Systems)
River Terraces, formation of, xv, 84

River Traffic, past and future, xiv, 31, 190-1

River Valleys, civilization in relation to, xv, 122, 128, 129;
development, xiv, 49-52;
general character, 56-7;
in old and new regions, iii, 33-5, 36-7, xiv, 48, 49, 57;
in stratified rock, 80-1, 82-3;
soils of, 70, 71, 218;
tributaries, 57;
usually excavated by their streams, 123-4
Riveters, pneumatic, iv, 129, v, 129
Roads, good, and farmers, vii, 230-1;
motor traffic and, v, 214-15;
rough and smooth, in relation to traffic, 206-7

Roaring Forties, i, 128, 380
Robert, Nicholas Louis, v, 291, 377
Roberts, astronomer, ii, 135-6, 361
Roberval, xvi, 104, 114
Robins, westward spread of, xii, 53
Robinson Cup Anemometer, i, 83
Roche, astronomer, ii, 157, 380
Rochelle Salts, from baking powder, viii, 136
Rochester, N. Y., drumlins near, xiv, 60
Roches Moutonnées, xiv, 56
Rock, Rocks, iii, 382, xiv, 17;
ages, how determined, iii, 17-19;
blasting of, v, 100, 261;
blocks and joints in, xiv, 128-30;
carbon dioxide absorbed by, viii, 49;
chemistry of, 192-5;
classes, iii, 12-13, xiv, 17-19;
coloring, iii, 25-6, 44;
color changes, viii, 194;
composition, 192-3;
disintegration, chemical, and physical, viii, 194-5, 338 (see Weathering of Rocks);
erosion of (see Erosion);
formations, iii, 379;
fracturing and folding (see Faults, Folding);
geology the study of, iii, 9, 12;
geological history, 164-248;
ground water effects on, xiv, 141;
in interior earth, iii, 108, 110;
joints, 23, xiv, 128-9;
land forms determined by, 43-4, 80-113, 125-7;
metal-bearing, iii, 355-70;
non-metalliferous, 370-6;
oldest, 160, 163, 168-9;
permeability of, xiv, 137;
plucking of, iii, 29;
primary and secondary, viii, 191-2;
rotten and bed, iii, 26, xiv, 64;
specific gravity, 11;
stream adjustment to, 160, 175;
striation, iii, 63, xiv, 56;
structure, defined, iii, 383;
structural changes, 83-98;
subsurface exploration, v, 262-3;
undermining or sapping of, xiv, 131;
weathering of (see Weathering)
Rockaway Beach, iii, 58
Rock Basins, iii, 142-3, xiv, 202-3
Rock Crystal, iii, 337
Rock Debris, as deep sea deposit, iii, 55;
carried by ice, 68;
carried by winds, 73
Rock Drills (see Drills)

Rockefeller Foundation, International Health Board of, x, 171-6

Rocket Lightning, i, 149, 152
Rockets, in aerology, i, 22-3
Rock Flour, xiv, 69
Rock Gypsum, iii, 331, 375-6
Rocking Stones, iii, 70
Rock Pigeon, xii, 265
Rock Rabbits, xii, 304
Rock Salt, iii, 374-5, xiv, 209
Rock Saws, ancient, xvi, 67
Rock Slides, earthquakes and, xiv, 333-4
Rocky Hill Sill, xiv, 109, 111
Rocky Mountain Forest, xiv, 373-4
Rocky Mountain Revolution, iii, 218, 219;
dinosaurs destroyed by, 298
Rocky Mountains, age of, iii, 191, xiv, 235;
birth of, iii, 218-19;
coal areas, 348;
forming agencies, 230;
fossils found in, 263;
geological strata, 138, 177, 184;
glaciers of, 240, xiv, 54-5;
granite-cored, 111, 228;
lakes in, iii, 143;
mineral wealth of, xiv, 237;
plateau west of, 220, 380;
red beds, iii, 208;
rejuvenation in Tertiary time, 231;
rock weathering in, xiv, 76;
sea over, iii, 130, 181, 184, 195, 197, 213;
thrust faulting in, 90;
volcanic activity, 229
Rodents, xii, 285-96
Rods, of eye, xi, 84, 89-90, 96
Rods, vibration of, iv, 213-15, 223-4

Roemer, discovery of speed of light, ii, 50-60, 91;
transit instrument, 58

Roentgen, Prof., vii, 249;

X-ray discovery, iv, 55, 317, x, 184, xvi, 192-3

Roentgenography, x, 185-6, 373
Rogers, Samuel Baldwin, xvi, 174
Rohlfs, explorer, i, 210
Rokitansky, Carl, x, 113
Roller-bearings, v, 205-6
Roller Mills, introduction, v, 381
Rollers, friction-saving by, v, 204-5, 205-6;
not found in nature, 16, 215
Rolling Country, iii, 34
Rolling Friction, v, 203-4, 207, 214-15

Romance Languages, descent from Latin, xv, 160

Romanche Deep, xiv, 289
Roman Empire, Alps Mts. and, xiv, 240;
growth and fall, 307;
metal supplies, 237;
medicine under, x, 25-31;
survey of, xvi, 98
Roman History, Alps Mountains in, xv, 137-8
Roman Numerals, xv, 183

Romans, character and civilization, xvi, 97-8;
divisions of day, v, 57;
elephants of, xii, 302;
gods of, xv, 344;
knowledge of loadstone, vi, 28;
plants known to, xiii, 215, 216, 253;
superstitions of, xv, 355;
taste and smell, cultivation by, ix, 98
Roman Soldiers, javelins of, xv, 213
Rome, civilization of, xv, 122;
copyists and books of, xv, 178-9;
fire veneration in, 234;
lampreys in ancient, xii, 130-1;
policy with conquered peoples, xv, 155-6;
sleeping sickness in, x, 301
Römer, Ole, thermometer of, i, 69
Rondeleti's Shark, xii, 145
Rood, O. N., i, 146
Roofing, copper, viii, 163

Rooms, appearance of filled and empty, xi, 187;
ventilation of, ix, 268, 269
Room Temperature, iv, 137 (fig.)
Roonhuyze, Hendrik, x, 80
Roosevelt, Theodore, African trip, xvi, 16;
on rain forests, xiii, 365;
on the caribe, xii, 159
Root, C. J., wheat studies, i, 253
Rootcap, xiii, 17-18
Root Hairs, xiii, 17, 91-4
Rootless Plants, xiii, 15
Roots of Plants, xiii, 15-22;
downward growth, 84-6;
functions, 15-22, 61, 80, 91-4;
galls, 98;
nitrogen absorption, 98;
of scavenger and parasitic plants, 99, 100;
sugar storage in, ix, 27-8
Rootstalks, xiii, 22-3;
potatoes as, 24 (fig.);
reproduction from, 43, 182-3, 215, 217-18
Ropes, materials of, xiii, 10, 239, 240, 241
Rosales, antiquity, xiii, 324-5
Rose Apples, origin, xiii, 226
Rose Beetles, and magnolias, xiii, 130-1
Rose Bugs, xii, 124
Rose Family, xiii, 197-8
Rosemary, source, xiii, 205
Rosenau, quoted, i, 328, 329
Rose of Sharon, xiii, 200
Rose Quartz, silica in, viii, 90

Roses, generic and specific names, xiii, 170-1;
leaf arrangement, 37, 38;
petal arrangement, 190
Rose's Fusible Metal, iv, 162
Rosetta Stone, xv, 172
Ross, Sir Ronald, x, 156-7;
article on, 155 note
Ross Antarctic Expedition, xvi, 142

Rosse, Lord, discovery of spiral nebulæ, ii, 361, 372, 380;

Leviathan reflector, 16-17, 105-6
Rossignol, Jules, i, 348
Rotary Converters, vi, 342-8, vii, 199, 365
Rotary Engines, v, 148
Rotary Press, v, 301, 305-6, 378, 379
Rotation, iv, 85-6;
energy of, 83-5;
magnetism of, ii, 178;
researches in dynamics of, 166-7
Rotation of Crops, viii, 342-6
Rotation of Earth, ii, 43;
ancient Greek beliefs, 28, 36, xvi, 81;
changing speed, ii, 74, 375, 376, 377;
De Cusa on, xvi, 102;
deflection of moving bodies by, i, 124-5, xiv, 32, 303, 348, 351;
effect on earth's shape, ii, 69;
effect on gyroscope, iv, 255;
effect on weights, ii, 69, iv, 74-5;
measure of day, 15-16;
precession in relation to, ii, 71;
proved by aberration orbits of stars, 92;
rising of sun due to, xvi, 12
"Rotten" Plants, xiii, 99-100
Rotten Rock, iii, 26, xiv, 64
Rotterdam, Holland, xiv, 271
Roughness, sensation of, xi, 128
Roundheads, racial division, xvi, 49
Roundworm, x, 200
Rousseau, philosophy of, xvi, 111, 117
Routine, in relation to will, xi, 261
Roux, antitoxin work of, x, 396;
pupil of Pasteur, 143
Roving, cotton, v, 272-3

Rowland, Prof. Henry A., heat work of, iv, 49-50;
on atoms, viii, 187
Rowntree, categories of therapy, x, 380;
kidney test, 378;
on therapeutic science, 334
Royal Families, origin of, xv, 366
Royal Society of England, xvi, 111-12;
Duchess of Newcastle's visit to, iv, 53
Rozier, M. de, v, 220-1
Rubber, artificial, viii, 257;
chemistry and manufacture of, 257-8;
electrification of, iv, 257, 259;
economic importance, xiii, 11, 208;
history and production, 245-9;
source of, xiv, 383
Rubbers, wearing of, x, 306
Rubber Trees, xiii, 245, 247-8
Rubidium, viii, 128, 132, 133;
spectrum of, 302;
symbol and atomic weight, 383
Rubies, variety of corundum, iii, 327
Ruby Glass, viii, 282
Rudolphine Tables, ii, 44, 216
Rulers, origin of, xv, 263-7
Rum, making of, viii, 250
Rumford, Count, heat theory of, iv, 47-8;
on friction and heat, xvi, 125, 131
Ruminants, xii, 311-12
Rumor, autosuggestion in, xi, 304
Runge, chemist, xvi, 163
Runners, in transportation, v, 214-15
Running, as exercise, x, 304;
reflex processes in, ix, 155-6
Rusby, H. H., on Amazon region, xiii, 360
Rush, Benjamin, x, 104
Rushes, ancient, iii, 254;
origin and products, xiii, 244

Russell, giant and dwarf star theory, ii, 150-1, 153, 309, 310, 382, 384;
photographic work, 130;
studies of binaries, 326, 328, 329
Russia, agricultural meteorology, i, 249-50;
beet sugar production, xiii, 216;
bison of, xii, 329;
elk in, 318;
forests and grasslands, xiv, 380-1;
gold production, iii, 365;
harbors closed by ice, xiv, 267;
loess deposits, 72;
meteorological service, i, 223, 228;
Napoleon's invasion, 306-7;
oil output, iii, 350, 354;
plains of, xiv, 217;
rainfall of, 355;
rodents of, xii, 294;
sleeping habit of peasants, xi, 285;
steppes
(see Steppes);
wheat cultivation, xiii, 211;
winters in, xiv, 347;
"Young Women's Summer", i, 362
Russian Alphabet, xv, 176
Russian Language, xv, 162
Rust, of wheat, xiii, 13, 71
Rusting, of iron, iii, 25, viii, 9, 10, 155-6
Rutabaga, xiii, 19, 223
Ruthenium, viii, 173;
symbol and atomic weight, 383;
valence of, 178, 180
Rutherford, chemical work, xvi, 120, 177
Rye, food value, viii, 364;
native of Old World, xiii, 182;
phosphate requirements, xiv, 67
Sabbath, among early Jews, x, 15
Sables, xii, 350
Sacandaga River, iii, 245
Saccharide, viii, 381

Saccharose, viii, 226-7, 242-3 (see Cane Sugar)

Sacrifices, religious, xv, 347-8, 354, 358-9
Sacrum, ix, 64 (fig.), 66
Saddle (meteorology), i, 238, 380
Safety Devices, vii, 32-3
"Safety First," vii, 33, 355, xi, 365
Safety Matches, viii, 88
Safety Valve, earliest use of, iv, 171
Saffron, origin, xiii, 255
Sagebrush, xiv, 380
Sagitta, xii, 18
Sago, source of, viii, 243
Sago Palm, xiii, 309
Sahara Desert, antelopes of, xii, 327;
depressions of, xiv, 205;
dust from, i, 55, iii, 54;
harmattan, i, 134;
impenetrability of, xv, 136;
largest desert, xiii, 377;
rain and snow in, i, 210;
sand storms, iii, 73

Sailing, against wind, iv, 77 (fig.), v, 182, 186-8

Sailing Vessels, historical development, v, 75, 111, 182, 188-9;
relative decline of, i, 37
Sails, evolution of, xv, 265
St. Anthony Falls, xiv, 171;
rate of recession, iii, 246
St. Cæsarius, i, 132
St. Elias Range, volcanoes of, xiv, 315;
youthfulness of, 96, 235
St. Elmo's Fire, i, 157-8, 380;
as ignis fatuus, 347
St. Gothard Tunnel, xiv, 240, 241;
heat encountered in, iii, 121
Saint Helena, groundsel of, xiii,345;
volcanic origin, xiv, 277, 289, 316
St. Helens, Mount, xiv, 315
St. John, astronomer, ii, 82, 154
Saint John's Bread, xiii, 226
Saint Lawrence, Gulf of, iii, 235;
Bird Rock of, xii, 253;
lows (cyclones) in relation to, i, 137
St. Lawrence River, discovery of, xiv, 310;
historical importance, 191;
white whales of, xii, 297

St. Lawrence Valley, geological history, iii, 78, 195, 232, 234, 235

St. Louis, early growth, xiv, 219;
power supply from Keokuk, v, 83;
water supply, viii, 326
St. Malo, Gulf of, tidal system, v, 176
St. Martin, Alexis, ix, 240, x, 121
St. Martin's Summer, i, 362, 381
St. Mihiel Salient, xiv, 91
St. Patrick, legend of, xii, 217
St. Pierre, destruction, iii, 103, xiv, 325

St. Vincent, eruption of La Soufrière, xiv, 28

Saint Vitus, x, 360
St. Vitus Dance, rheumatism and, 224
(see also Cholera)
Saké, Japanese, xiii, 213
Sakhalin, separation from Asia, xiv, 274
Salads, food value of, x, 273
Salamanders, xii, 169, 170-3, iii;
ancient, 285;
evolution of, xii, 167, 168;
regeneration in, 170;
sense organs in, 169

Sal Ammoniac, solution of, temperature produced, iv, 136, 175

Sal Ammoniac Cell, iv, 297, 298 (fig.), vi, 59

Salerno University, x, 36-7, 38, 77, xvi, 100
Salesmanship, psychology of, xi, 334-42
Saliceto, surgeon, x, 38-9
Salicylates, in rheumatism, x, 381
Salicylic Acid, viii, 236, 239, 372
Saline Lakes, xiv, 206-9, 212

Salisbury, Prof., relief classification, xiv, 27

Saliva, conveyance to digestive canal, ix, 189-90;
in digestion, viii, 358, ix, 227-30, 235-6, x, 319;
of infants, ix, 346;
secretion of by chewing, 163;
thirst relief by, 89
Salivary Glands, blood supply of, ix, 197;
fear effects on, 166, 221, xi, 132;
reflex control of, ix, 163, 165;
response to tastes, xi, 74, 76
Salmon, xii, 154, 156-8;
canned, calories in, ix, 299;
eggs, number of, xv, 20;
instinct of, xi, 46;
river habits of, ix, 174-5;
shooting of, xv, 227
Salpae, xii, 19-20, 129
Salsify, origin, xiii, 223
Sal Soda, viii, 135
Salt, Common (see Common Salt)
Salt Lake City, site of, xiv, 208
Salt Lakes, viii, 139;
persistency of, xiv, 199
Salt Pork, calories in, ix, 299
Salton Sink, iii, 156, xiv, 204-5
Salts, defined, viii, 381;
digestion of, 356;
electrolytes, 125;
esters, 221;
formation and nature, 114, 115-18;
formers (halogens), 84;
in body fluids, ix, 174, 175-6;
in blood, filtered by kidneys, 272, 273;
in fabrics, viii, 256;
in sea and inland waters, 138-9, 195-7, xiv, 295-7;
in sea, gradual accumulation, ix, 175-6;
ionization in solution, viii, 119-25, 300-1;
most important, 130;
natural deposits, 138, 195-7, 275;
nomenclature, 98;
organic life in relation to, ix, 174-6;
positive and negative elements, viii, 126;
protoplasm dependence on, ix, 32, 174;
uses, viii, 146
Salvador, Izalco volcano, xiv, 321;
public health fellowships, x, 172
Salversan, x, 381
Salvia, corolla, xiii, 201;
flower, 48, 204, 205;
petal arrangement, 190
Samara, winged fruit, xiii, 58
Samarium, atomic weight and symbol, viii, 383
Samoan Islands, native prayers, xv, 345-6
Sampson Cell, vi, 138, 144
Samson, Hebrew sun-god, ii, 20
Sanctorious, Santoro, x, 70-1
Sand, corrasion by, iii, 72, xiv, 77;
form of rock, 18;
rock formed from, iii, 13 (see Sandstone);
wind-carrying of, 71, 72 73, 74-5
Sand Bars, iii, 57, 58;
effect on waves, v, 124
Sand Blast, iv, 129-30, v, 135-6;
natural, xiv, 77
Sand Cherries, origin, xiii, 226
Sand Dunes, iii, 71;
migration, 74;
vegetation xiii, 149
Sand Filters, viii, 319-20
Sand Hogs, v, 117
Sand Hoppers, xii, 82, 85
San Diego, Cal., North Island station, i, 48
Sand Myrtle, petals, xiii, 202
Sandpaper garnet, iii, 330
Sandpipers, xii, 262
Sand Saucers, xii, 73
Sandstone, iii, 13, 382, xiv, 18;
bad conductor of heat, 12;
frost destruction of, 77;
jointing in, 133;
occurrence, iii, 372;
permeability, xiv, 137;
quartzite from, iii, 169, 189;
weathering of, 25, 27

Sandstone Belt, of eastern U. S., xiv, 107, 111-12

Sandy Hook, iii, 58
Sandy Regions, sledges used, v, 214-15
Sanford, F., on ignis fatuus, i, 249
San Francisco, bubonic plague in, x, 164;
harbor of, xiv, 268-9;
latitude and climate, 345;
power supply, vi, 363
"San Francisco," wreck of the, i, 272
San Francisco Bay, xiv, 257-8, 268-9
San Francisco Earthquake, iii, 94-7;
cause of, xiv, 128, 340;
experience with building types, 343;
faulting at time of, iii, 89;
lateral displacements in, xiv, 335;
origin of fault, iii, 224
San Francisco Mountains, xiv, 102
Sanguine Temperament, xi, 153, 159, 205
Sanitary Chemistry, viii, 317-33
Sanitary Sewage, viii, 324
Santa Maria Eruption, xiv, 314, 325-6, 328-9;
earthquakes preceding, 338
Santo Domingo, sugar cultivation, xiii, 215
Santorin, volcano, xiv, 317, 319
Santorin Islands, xiv, 319
Santos-Dumont, v, 227-8, 382
Sao Paulo University, Brazil, x, 172
Sap of Plants, xiii, 80, 81;
distribution, 23, 24, 25-6;
functions, ix, 27
Saplings, in temperate forests, xiii, 369
Sapodilla, origin, xiii, 225, 226
Saponification, viii, 221, 381
Sapote, origin, xiii, 226
Sapper, on Santa Maria eruption, xiv, 328
Sapphires, iii, 327;
electrification, vi, 12
Sapping, of rocks, xiv, 131
Saprophytes, xiii, 99-100;
in heath family, 202;
orchids as, 185
Sapwood, xiii, 24, 25, 26, 177
Sarasin, P. & F., i, 58

Saratoga Springs, carbon dioxide in waters, xiii, 49;
known to Indians, xiv, 145;
seaweed reefs near, iii 251;
stream changes around, 243-4
Sarawak, war play of natives, xv, 307-8
Sardinian Rise, xiv, 291
Sargasso Sea, xiii, 73;
ianthina of, xii, 19;
temperature of waters, 21
Sargon the First, writings of, ii, 19-20
Saros, Chaldean, ii, 27, 209-10, 215
Särs, naturalist, xvi, 148
Sarsaparilla, source, xiii, 188, 255
Sassafras Family, xiii, 196-7

Sassafras Tree, antiquity of species, xiii, 324-5;
distribution, 351;
earliest appearance, 318;
northern limits, 367;
stamens and pistils, 120
Satellites, in solar system, ii, 163;
habitability, 249-50, 262;
of various planets, 241, 249-50, 261-4, 268;
of moon, 208;
orbits of, 197;
theories of origin, 370, 371, 374, 380;
weighing of primaries by, 75-6
Satin Spar, iii, 331, 332
Saturated Air, i, 14, viii, 67
Saturated Color, xi, 90
Saturated Vapor, iv, 167-8, v, 140;
temperature table, iv, 173
Saturation, chemical, viii, 206, 230-1
Saturn (planet), ii, 264-6;
comet families, 271;
"great inequality," 87;
life on, 249;
photographic study, 133;
rings, 133, 264-6;
rings, discovery, 54, 96, 109;
rings, Cassini on, 59;
rings, Huygens on, 54, 57;
rings, Keeler on, 120-1;
rings, Laplacian theory, 370, 372;
rotation period, 377;
satellites, 249-50, 264;
satellites, discovery, 85, 104, 146;
size and orbit, 162, 163;
weight, 77
Saurians, xii, 182, 203
Sauropods, iii, 288-9
Savages, æsthetic arts of, xv, 296;
attitude toward nature, 329;
body mutilations among, 257-60;
brain in, 63-4;
canoe-making, 262;
child-bearing among, 278;
clothing of, 252, 254, 255;
cooking methods, 283;
counting ability, ii, 9, xv, 180;
dances of, 305-6, 310-12;
dramatic art of, 303-10, 322;
feet of, 61;
fire sources and generation, 230-1;
fire worship, 234;
fish-catching methods, xv, 227;
grouping tendency, 363;
hair decorations, 260-1;
hunting methods, 222-3;
hunting stage of present, 187, 192-6;
keenness of senses in, 228;
leaders and rulers, xv, 363-6;
life of, remarks on, 9-10;
marriage among, 278-82, 283-5;
marriage ceremonies, 292;
musical scales of, iv, 206;
music of, xv, 312-15, 316, 318;
natural selection among, 47;
obedience to customs and laws, 374-5;
painting of body, 255-6;
poetry of, 319-21;
poison uses by, 227-8;
polygamy among, 287;
rain-makers, i, 334;
religious ideas, xv, 234, 292, 304-6, 326-59, 375, 380;
salt esteemed by, ix, 95;
sex relations among, xv, 277-8;
similarity to ourselves, 9;
songs of, 319-21;
time divisions, v, 57;
tribal morality of, xv, 374;
war dances, 307;
writing a mystery to, 164
"Savannah", steamship, v, 192-3, 378
Savannah River, shad time in, xii, 155
Savory, source, xiii, 205
Sawfish, xii, 148-9;
teeth of, 134
Sawflies, xii, 125
Saws, chisel form, v, 46;
electric, on farms, vii, 229;
gang, xi, 268
Saxon Chronicle, eclipse recorded in, ii, 210
Scale, musical, iv, 206-9 (see Musical Scale)
Scale Insects xii, 112
Scales, of fishes, xii, 134-5
Scallops, xii, 59, 60, 65
Scandinavia, coasts concordant, xiv, 249;
early seamanship in, 261-2;
lakes of, 200;
level changes in, iii, 80, xiv, 33-4, 35-6;
rock formations, iii, 172, 178
Scandinavian Languages, xv, 162
Scandinavians, in Nordic group, xvi, 48
Scandium, discovery of, viii, 180;
symbol and atomic weight, 383
Scaphopoda, xii, 58, 74
Scarabs, xii, 123
Scarf Clouds, i, 104, 381
Scarlet Fever, effects on ear drum, ix, 103;
immunity to, x, 207;
virus of, 141
Scarpa, surgeon, x, 104
Scarring, of body, xv, 257-8
Scars, xi, 248;
formation of, ix, 48, 287;
treatment of disfiguring, x, 189
Scar Tissue, ix, 348
Scepters, xv, 207-8
Schadenfreude, xi, 351
Scheele, Carl Wilhelm, xvi, 120-1, 177

Schiaparelli, studies on Mars, ii, 229, 235, 237

Schiff, thyroid studies, x, 350
Schiffli Machines, v, 286, 287
Schiller, skull capacity, xv, 40
Schist, iii, 169, 189, 382;
jointing of, xiv, 133;
metamorphic rock, 19
Schizogony, x, 158
Schizopoda, xii, 19
Schleiden, Matthias, x, 119, 120, xvi, 142
Schleswig-Holstein, föhrden of, xiv, 259
Schlick, Dr., v, 342, 384
Schmidt, Dr. William, i, 193
Schneefresser, i, 133
Schoharie Creek, xiv, 179
Scholastic Philosophy, xvi, 99, 100
Schönbein, xvi, 163
Schönlein, Johann Lucas, x, 113
Schools, seats and desks in, ix, 56-7;
teaching of hygiene in, x, 283-4;
ventilation, ix, 97
Schuchert, quoted, iii, 205, 278, 293, 297
Schultze, Max, x, 131;
on protoplasm, xvi, 166
Schuster, astronomer, ii, 178, 224
Schwann, Theodor, x, 119, xvi, 142
Schweitzer's Reagent, viii, 256
Science, Airy on progress of, ii, 82;
Aristotle on, xvi, 88;
art and, iv, 9;
birth of true, ii, 9-10, 86;
exact and complex, x, 368;
field of, xvi, 35;
history of, xvi, 39-198;
imagination in, xvi, 58-9;
importance and interest, xvi, 9-34;
industry and, v, 15;
invention and, iv, 44-5;
"laws" of, iv, 19;
meaning of, vi, 10, xvi, 39-40;
measures and units in, iv, 45-6;
methods of, 26, vi, 10, xvi, 10, 34-5;
philosophy and, 112, 115;
principles of, remarks on, iv, 9-10;
progress, means and ways, xvi, 30, 41, 46, 75, 76, 98, 116, 118;
realm of, vi, 107;
religion and, iv, 27-8, xvi, 42, 44-5;
St. Augustine on, 99;
specializing axiom, x, 43;
understanding of, xvi, 10-11, 30-4;
unity, 34, 35
Sciences, abstract and concrete, xvi, 42;
development of, iv, 9-11;
historical sequence, xvi, 35;
interrelations and boundaries, 35, 42;
summarized, 36-8
Scientific Expeditions, xvi, 123, 140, 142
Scientific Laws, iv, 19, vi, 106;
principle of final common path in, xi, 23
Scientific Research, in World War, v, 360
Scientific Tendency, growth of, vi, 330
Scientists, methods of, xvi, 10, 11, 41;
realm and aim of, vi, 107
Scoresby, Capt. William, i, 173, 361
Scoriæ, of volcanoes, xiv, 323
Scorn, facial expression of, xi, 133;
sentiment of, 148
Scorpion Flies, xii, 106
Scorpions, xii, 89-90;
ancient, iii, 278
Scotch Fir, in Danish peat bogs, xv, 87
Scotch Mist, i, 108, 377
Scotland, bag-pipes of, xv, 317;
corries of, xiv, 58;
fjord coasts, 258, 259;
former volcanoes, 318;
Gulf Stream effects, 304;
Highlands, conquest of, 243;

Highlands, geology of, iii, 172, 178, xiv, 122-3, 272;
lakes of, 200;
latitude of, 345;
lava plateau, 103-4;
lowlands, 123;
scurvy and potato crop, x, 266;
shoals on west coast, xiv, 47;
wave pressure on coasts, 300;
wild deer of, xii, 317
Scott, explorer, death of, x, 252

Scott, Prof. W. B., author Physiography, Vol. xiv;
quoted, iii, 17, 18, xii, 332
Screens, shadows of, doubled, iv, 332-3
Screw, v, 37-9;
Archimedes, iv, 26, 27 (fig.);
form of inclined plane, 90;
friction with, 93;
gimlet-pointed, v, 379;
mechanical advantage of, iv, 91-2
Screw and Cogged Wheel, iv, 92, 93 (fig.)
Screw Pines, xiii, 187, 354

Scribes, ancient and modern, xv, 177 (fig.), 178

Scrub Vegetation, xiv, 378-9

Scud, cloud form, i, 101, 381

Scully, William C., on snakes, xii, 214-15, 227-8, 231-2

Sculpture, beginnings and development of, xv, 108-9, 111 (fig.), 117-20, 300-2

Schultetus, surgeon, x, 78
Scum, of pools, xiii, 13, 73
Scurvy, x, 264, 265-6;
vitamines to prevent, 261, 262, 263
Scythes, development, v, 240-1
Sea, animal life in (see Marine Animals);
geological work of, iii, 51-8;
man's invasion of the, v, 182-202
(see also Ocean)
Sea Anemones, xii, 23, 37-8
Sea Bathing, x, 312
Sea Birds, xii, 251-4;
feathers of, 244
Sea Breezes, i, 131, 381

Seacoasts, civilization in relation to, xv, 128, 129 (see Coasts)

Sea Cucumbers, xii, 50
Sea Devils, xii, 150
Sea Elephant, xii, 335
Sea Fans, xii, 37, 43
Sea Fleas, xii, 85
Sea Grapes, xii, 75
Sea Hares, xii, 68
Sea Horses, xii, 163
Sea Island Cotton, v, 269, 270, xiii, 236-7
Sea Level, changes in, iii, 83
Sea Lilies, iii, 259, 268-70, xii, 48-9

Sealing Wax, electrification of, iv, 257-8, 258-9

Sea Lions, xii, 333-4

Seals, xii, 333-4, 335

Seamanship, developed in Scandinavia, xiv, 261-2

Sea Mosses, iii, 259, 270
Sea of Darkness, legend, i, 55
Sea Mouse, xii, 54
Sea Necklaces, xii, 73
Sea Pens, xii, 43
Sea Purses, xii, 148
Searchlights, iv, 352
Searchlight Shells, v, 372
Sears, astronomer, ii, 153, 298
Searles Lake, potash supplies, viii, 279

Sears Roebuck & Company, small power sets, vii, 232

Sea Scorpions, iii, 260, 278
Sea Serpents, ancient, iii, 288
Sea Serpent Stories, origin of, xii, 80, 143
Sea Shells, xii, 71-4
Sea Sickness, cause, xi, 127;
James on phenomena of, x, 242
Sea Slugs, xii, 68
Sea Snakes, xii, 225, 229
Seasons, phenology, i, 254, 255
Sea Swallows, xii, 264
Sea Turtles, xii, 192-3;
catching of, 139-40
Seatworm, x, 200

Sea Urchins, iii, 259, 269 (fig.), 270, xii, 50

Sea Walls, of Galveston, xiv, 303;
wave action on, 301-2

Sea Water, atmospheric carbon absorbed by, i, 14;
density of, iv, 149;
effect on seed, xiii, 346;
gold in, viii, 197, xiv, 295;
organic life in relation to, viii, 355, ix, 174, 175;
radioactive matter in, i, 143;
salts and other dissolved substances, iii, 51-2, viii, 139, 140, 279, xiv, 295-7;
salts in, gradual accumulation, ix, 175-6
Seaweeds, classification, iii, 251;
flowerless plants, xiii, 13, 43;
great Pacific, 27, 66-7;
habits and character, 72-3;
iodine in ash, viii, 197;
potash from, 279, xiv, 67, 68;
Pre-Cambrian, xiii, 304;
remains in old strata, iii, 20, 250, 251, 252, 256;
reproduction, xiii, 166
Sea Wrack, fertilization, xiii, 151-2
Sebaceous Glands, ix, 313-14, x, 310
Sebum, x, 310
Secchi, Fra Angelo, ii, 17, 114, 115
Secchi Classification (stars) ii, 115-16, 118
Second, unit of time, iv, 70
Secondary, Cyclonic, i, 238, 381

Secondary Cells, iv, 383, vii, 363 (see Storage Batteries)

Secondary Coils, iv, 383;
of transformers, vi, 308
Secondary Currents, vii;
in induction coils, vii, 243
Secondary Rock (see Sedimentary Rock)
Secondary Spectrum, ii, 101, 108
Secretin, x, 325
Secretion, Borelli on, x, 72;
metabolism of, ix, 159
Secular, meaning in astronomy, ii, 74
Secular Parallax, ii, 316-17

Sedentary Habits, food requirements with, ix, 297;
sluggishness from, 223, 251
Sedges, xiii, 187-8;
family, 179, 180;
fertilization, 148;
first appearance, 319;
product and origin, 244;
stems, 182 (fig.)

Sedimentary Rocks, iii, 13, 382, viii, 191, xiv, 18;
folding of, iii, 85, xiv, 32, 36 (see Folding of Rock);
fossils in, iii, 16-17;
jointing of, xiv, 130;
land forms in, 44, 80-99;
marine, 19-20;
oldest, iii, 163, 165, 167;
original horizontal formation, xiv, 36;
weathering of, 79
(see also Strata)
See, on binaries, ii, 377
Seed of Plants, xiii, 59-62;
absent in some plants, 13, 14, 215, 218;
of annuals, 53;
destruction of, xv, 21;
dispersal methods, xiii, 55-9, 338-48;
dispersal by sea currents, xii, 42;
fats from, viii, 246;
germination (see Germination of Seed);
naked and enclosed, xiii, 174-5, 178;
number and increase, xv, 19;
persistence of life in, ix, 16-17;
small-sized, xiii, 344;
storage of food in, 96, ix, 27-8, 278;
survival of, by what determined, xv, 22, 23, 25;
waste of, xiii, 11-12
Seed-bearing Plants, iii, 251
Seed Ferns, iii, 251, 254-5
Seed-habit, beginning of, xiii, 309, 310
Seeding Machines, v, 244
Seed Leaves, xiii, 60-1 (see Cotyledons)
Seedless Plants, xiii, 13, 14
(see also Cryptogams)
Seedlings, destruction of, xv, 21
Seeing Machines, v, 331-2, 334-5
Seihun River, xiv, 185
Seine River, tidal basin, v, 176;
trench of, xiv, 89
Seismographs, iii, 93
Seismology, xiv, 337

Selection, artificial, ix, 327, xvi, 154-5, 157-8;
natural (see Natural Selection)

Selenite, iii, 331

Selenium, sensitiveness to light, v, 332, 334;
symbol and atomic weight, viii, 383
Seleucus, astronomer, ii, 28
Self, "real," x, 302
(see also Personality)
Self-abasement, xi, 55;
in admiration, 147
Self-assertion, xi, 56, 146
Self-Control, xi, 257
Self-encouragement, xi, 278;
in salesmanship, 336-40
Self-excited Dynamos, vi, 187, 191

Self-Feeling, in various sentiments, xi, 146-50

Self-Fertilization of Plants, xiii, 120;
avoidance of, 152-3;
Darwin on, 135;
preventive methods, 120-2, 123, 127-30, 131, 134, 135, 141-2;
as last resort, 135-44
Self-Gratification, impulse of, xv, 185
Self-induction, vii, 375

Self-interest, not the motive of crowds, xi, 330-1

Self-luminous Objects, ix, 105-6

Self-Maintenance, impulse of, xv, 185, 186-204, 273

Self-Perpetuation, impulse of, xv, 185, 273

Self-preservation, emotions of, ix, 153, 165-6, 171-2;
instinct of, x, 9-10, 282-3, xv, 273

Selfridge, Admiral, periscope, v, 200

Self-Sacrifice in plants, xiii, 52-3, 61-2, 117, 151

Self-Starters vi, 238-9, vii, 120, 127, 142-3
Selkirk Mountains, snow mushrooms, i, 116
Semaphores, i, 282

Semicircular Canals, ix, 89-90, 101 (Fig.), x, 126;
in fishes, xii, 137
Semites, rule of fathers among, xv, 367
Semitic Languages, xv, 161-3
Semitic Religion, sun-worship in, ii, 20
Semmelweis, x, 114, 115, 122, 144;
debt of women to, x, 149
Seneca, on comets, ii, 85
Seneca Lake, xiv, 203;
delta in, 211
Senecio, seed dispersal, xiii, 345
Sensation, xi, 62-4;
defined, 67-8;
dependent on motor response, 43, 66, 74-5, 102-3, 110-11, 118-21, 123-4, 202-3;
dependent on sense organs, x, 118;
hallucinatory, 358;
nervous impulse from, xi, 19;
perceptions and, 160-1;
physical effects, 67-8;
physical essentials and cost, 25;
threshold of, 71
(see also Senses)
Sense Organs, at birth, ix, 349-51;
cell structure of, 22;
classes, 86;
condition in attention xi, 228-9;
connections with brain, ix, 142-4, 145-6;
connections with dendrites, xi, 19;
connections with muscles, ix, 19-20, 122, 124-37, 139, 140;
development in embryo, xi, 35;
in amphibians xii, 169;
in fishes, 137-9;
of skin, ix, 314;
part of, in maintaining life, 19, 21, 23, 166-7;
percentage of error, xi, 184-5;
receptive attunements, 62;
sensations dependent on, x, 118;
threshold of sensation, xi, 71;
summation of stimulations, 21-2
Sense Perception, motions of, ix, 82
Senses, contact, ix, 86, 91-5;
distance, 86, 96-121;
hypnosis of, xi, 315;
internal, ix, 86, 87-91;
number and kinds, xi, 63-4, 109;
primary purpose of, ix, 86-7
"Sensible Temperature," i, 318, 381
Sensitive Plant, xiii, 113-14
Sensory Nerve Cells, ix, 125, 126 (fig.);
at birth, 348;
connections of, 129-31, 142
Sensory Neurones, xi, 21;
development in embryo, 34, 35

Sensory Reaction Type, xi, 155, 156-7, 158, 159

Sentiments, xi, 143-51;
in advertising, 345-6
Sepals, xiii, 45, 47
Separately-excited Dynamos, vi, 187, 191
Separate Origin Theory, xv, 69
Separation, energy of, iv, 82
Separators, electromagnetic, vi, 103-4
Sepia, origin of, xii, 79

September Massacres, honesty of crowds, xi, 331

Septicemia, x, 198
Septic Tanks, viii, 328
Sequoias, ancient and present, iii, 256;
Californian, xiv, 374;
climatic record in rings, i, 199-200, xiv, 362;
former distribution, 375
Serbia, Austria's control of, xiv, 306;
Turkish conquest, 243
Serbian Language, xv, 162
Series, chemical, viii, 381
Series Circuits, vii, 364, 375
Series Field of dynamos, vi, 189
Series Wound Motors, vi, 231-4
Serow, xii, 325
Serpentine, iii, 338
Serpents, xii, 211-38;
descent of, 203;
eggs, care of, xv, 275
Serpollet, flash boiler, v, 213
Serpula Tubes, xii, 55
Serums, used in diagnosis, x, 215-16;
use of, in disease prevention, 218, 296-7, xv, 49

(see also Antitoxins)
Serum Sickness, x, 212, 215
Serval, xii, 357

Servant Question, electricity and, vii, 74, 90

Sesheta star goddess, ii, 24
Seven, basic number, xvi, 80;
former supposed virtue of, ix, 115
Seventeen-year Locusts, xii, 112, 113
Severinus, Marcus Aurelius, x, 79
Severn River, tidal basin, v, 177;
tides of, xiv, 293
Seville, Giralda Observatory, xvi, 100

Sewage, composition, disposal, and purification, viii, 324-9;
in water supply sources, 318, 319, xiv, 140-1;
oyster and clam poisoning by, xii, 59;
plant fertilizing by, viii, 327, 343-4
Sewer Gas, harmlessness, i, 326
Sewer Pipes, bamboo stems as, xiii, 183
Sewers, rainfall and, i, 110
Sewing Machines, v, 283, 284-5, 379;
embroidering and lace-making, 285-8;
motor-driven, vii, 84-5
Sex, determination of, ix, 338-40, xvi, 156;
effectiveness of jokes on, xi, 355-6;
hereditary traits, bound up with, ix, 338, 340-1;
in flowers, xiii, 46-7;
in various trees, 191-2;
influence on disease, x, 237;
of twins, ix, 44
Sex Chromosomes, ix, 339;
hereditary traits carried in, 338, 340-1
Sex Determiners, ix, 338-9, x, 234, xvi, 156
Sex Glands, double functions of, x, 347

Sex Relations, among animals, xv, 274-7, 277-8;
among primitive men, 277-8;
varying ideas of morality in, 286
Sexual Feelings, xi, 63, 138, 139

Sexual Impulse in man and animals, xv, 273, 274;
repression of, x, 356
Sexual Reproduction (see Reproduction)
Sexual Selection, xv, 274

Seychelles Islands, coco-de-mer of, xiii, 60, 154

Shad, xii, 154-5;
river habits of, ix, 174-5
Shadbush, leaves of, xiii, 105
Shaddock, origin, xiii, 226
Shadoof, v, 18-19
Shadows, iv, 332-4;
colored, xi, 94-5;
in distance perceptions, 183;
in perception of solidity, ix, 120;
savage fear of, xv, 330
Shaft-sinking, v, 260
Shagreen, xii, 134

Shakespeare, pronunciation changes since, xv, 156

Shale, iii, 13, 382;
petroleum source, viii, 209-10;
schist and gneiss from, iii, 169, 189;
weathering of, 27
Shaler, Nathaniel, on lunar surface, ii, 376

Shallow Water Belt, xiv, 24-5 (see Continental Shelf)

Shamash, sun-god, ii, 20
Shame, Carlyle on, x, 306;
custom and, xv, 254-5
Shape, perception of, ix, 105
Shapers, metal cutting by, v, 47

Shapley, astronomer, ii, 17, 153, 326-7, 330, 337, 338, 339, 340, 356

Sharks, xii, 142-7;
caudal fin in, 133;
evolution, iii, 282, 284;
eyes of, xii, 138;
gill clefts in, 148;
scales of, 134;
sense of smell in, 139
Shark's Teeth, fossils of, xii, 142
Sharps, musical, iv, 208, ix, 100
Shasta Indians, arrows of, xv, 196 (fig.)
Shasta, Mount, iii, 106, 226
Shat-el-Arab, xiv, 185
Shaw, Lieut., aeronaut, i, 285
Shaw, Sir Napier, i, 139-40
Shear, plane and torsional, iv, 158
Shearing Machines, motors used, vi, 234-5
Shearing of Sheep, pneumatic, v, 130
Shears, as levers, v, 23, 46
Shearwaters, xii, 252
Sheep, xii, 324, 326;
anthrax of, Pasteur's work on, x, 140-2;
domestication of, xv, 197;
elastic cord in neck, ix, 59;
horns of, xii, 325, 328
Sheep-cold, i, 363

Sheep-raising, in New Zealand and Australia, xiv, 384

Sheet Lightning, i, 148-9, vii, 205, 213
Sheet Tin, viii, 161
Sheldrakes, xii, 257
Shellac, composition and use, viii, 264

Shell-Animals, origin and development, iii, 20, 264, 265-6, 272, 273-5

Shellfish, xii, 57-80

Shells (animal), calcium carbonate in, viii, 152, 354;
deposits, iii, 53, 54, 235, 257-8, 272;
formation of, xvi, 145;
rocks formed from, iii, 13, viii, 152
(see also Chert, Flint, Limestone)
Shells (artillery), v, 371-2, 373;
explosives for, viii, 260;
triple reports in World War, i, 193
Shell Worms, xii, 54-5
Shelter, man's need of, ix, 308-9

Shenandoah River, longitudinal character, xiv, 154;
piracy of, iii, 38-9
Shenandoah Valley, xiv, 167
Sherrington, Charles, x, 131;
quoted, xi, 12
Shetland Islands, storm waves in, xiv, 300
Shields, xv, 221
Shields River, Montana, xiv, 176
Shields, Tunnel, v, 122-4
Shin, bones of, ix, 68, 70 (fig.)
Shiners, xii, 161, 163
Shinleaf Plants, xiii, 99

Shipbuilding, developed in Scandinavia, xiv, 261

Ships, ancient and modern, xiv, 265;
bottoms, how cleaned, ix, 174, 175;
bow and stern shapes, v, 191-2;
concrete, 194-5;
gyroscopic stabilizing, 341-2;
handling in cyclones, i, 277-8;
Marconi distress system, vii, 284;
materials of hulls, v, 194-5;
measuring of position of, 65-6;
refrigerating systems, 353;
St. Elmo's Fire on, i, 157;
speed and driving power, v, 190-2;
strains, 194, 195;
water and air resistance, 190-2;
wireless directing, vii, 284, 285;
why they float, v, 95
(see also Steamships, Steel Ships)
Ships' Chronometers, v, 65-7
Shirt Tree, xv, 256
Shivering, heat production by, ix, 309-10
Shoals, xiv, 286;
aerial mapping, i, 47;
effect on waves, v, 124

Shoal Water Belt, xiv, 24-5, 46-7 (see Continental Shelf)

Shock, cause and treatment of, ix, 195;
kinetic theory, xi, 59;
low blood pressure in, x, 336
Shoes, mending of, by electricity, iv, 10;
proper and improper, ix, 69-70, x, 306;
working, xi, 279
Sholes, typewriter, v, 312, 380
Shooting-Star Plant, xiii, 203
Shooting Stars, ii, 164, 283-9;
altitude in air, i, 17
(see also Meteors, Meteorites)
Shops, displays and weather, i, 266;
electric wiring, vii, 57
Shore Lines (see Coasts)
Shore-Weed, distribution, xiii, 352
Short-Circuits, defined, vii, 375;
protection against, 35-50
Shortening Agents, viii, 232
Shorthand Typewriter, v, 313
Short Heads, skull index in, xv, 42
Shoulder Blades, ix, 63 (fig.), 66
Shoulder Girdle, ix, 66
Shoulder Joint, ix, 66;
dislocation of, 71
Shovels, most efficient lifts, xi, 362
Showers, curious, i, 355-9, 55
Shrews, xii, 366, 367, 368
Shrimps, class of, xii, 81, 82;
swimming of, ix, 39

Shrubs, garden, planting tables, xiii, 272-89;
hairy covering, 104-5;
in plant classifying, 175;
older than herbs, 319;
roots, 16
Shu, Egyptian god, xvi, 77
Shuman, Frank, solar engine, ii, 169;
sun-power plant, v, 177-8
Shunt Circuits, vii, 364
Shunt-Wound Dynamos, vi, 187-8, 191-2
Shunt-Wound Motors, vi, 229-31, 232
Siam, opium in, xiii, 253;
rivers of, xiv, 196;
viper of, xii, 230
Siberia, animals of, xii, 317, 349, 350, 356;
anti-cyclone of, i, 218;
extinct animals, iii, 16;
low temperatures, i, 209-10;
plains and table lands of, xiv, 217;
rift valleys in, 123;
rivers of, 195
Sibert, Maj.-Gen'l William, x, 187
Sicily, earthquake belt of, xiv, 340;
temporary island near, 319-20
Sickles, evolution, v, 240
Sickness (see Disease)
Sidereal Period, of moon, ii, 196
Siderite, viii, 156
Siemens, Sir William, xvi, 175, 176
Sierra Chica Observatory, ii, 146
Sierra Nevada Mountains, age, iii, 191;
canyons, 225;
cirques, 66;
exfoliation in, 24;
fault scarp of, 89, 225, xiv, 117, 122, 230;
fault valleys in, xiv, 127;
filled lakes of, 212;
former volcanic activity, iii, 226;
geological history, 136, 140-1, 213-14;
glaciers, past and present, xiv, 54-5;
granite core, iii, 112, xiv, 111, 228;
intense folding, 230;
lakes, iii, 143;
metamorphism in, xiv, 234;
Mother Lode gold belt, iii, 366;
power plants, v, 79, vi, 363;
precipitation on opposite sides, xiv, 355;
snowfall, i, 118-19

Sight (sense), iv, 346-7, ix, 104-21, xi, 83-97;
acuteness of, vi, 272-3;
arrival platform for, ix, 146;
center of, xi, 97;
defects of, 112-14;
deficiency, to what due, iv, 322;
development in infants, ix, 350, 351, xi, 40;
direction perception by, ix, 118, 120;
distance and depth perception by, 118-20;
illusions of, iv, 323, 326-9;
in fishes, xii, 138-9;
nerve of, xi, 29-30;
space perception by, 163, 169-70, 171-2, 173, 174-83;
touch and, ix, 92;
walking reflex from, ix, 158
Signal Fires, xv, 165-6
Signals, distress, wireless, vii, 284;
storm, i, 282-8

Signal Service, weather service called, i, 216

Signal Systems, of railroads, vii, 355-9
Signatures, magazine sections, v, 306-7
Sign Languages, xv, 148-51
Sign Lighting, vi, 280, vii, 339-48;
colors in, iv, 51;
psychology of, xi, 344, 345, 346

Silence, from interferences of sound, iv, 218, 219, 220-2;
horrors of world of, 51;
zones of, i, 189-92, 381
Silica, viii, 90; in earth's crust, 193;
in iron ore, iii, 356;
in organic compounds, ii, 243;
petrifying material, iii, 127;
residue of primary rock, viii, 195
Silicates, identification, viii, 201;
in earth's crust, 90, 193, 194, 198, 200-1;
in glass making, 281;
preparation of, 117;
specific gravities, 202
Silicles, xiii, 197
Silicon, viii, 19, 90;
atomic weight and symbol, 383;
compounds, 90;
in body tissues, 354;
in earth's crust, iii, 308, viii, 19, 129, 192;
in wireless detectors, vii, 269;
metallic, 300-1;
plant needs of, viii, 337, 341
Silicon Carbide, vii, 310 (see Carborundum)
Silicon Dioxide, viii, 90

Silk, as clothing material, ix, 311-12, x, 308, 309;
chemistry and manufacture, viii, 256;
dyes for, 269;
electrical conductivity, iv, 259;
electrification of, 257, 258, 259;
vegetable, viii, 255-6
Silkworm Moths, xii, 119

Silkworms, Pasteur's work on diseases of, x, 140

Sills (geological), xiv, 108-10;
columns in, 130; illustration, 107
Sill Tunnel, corrasion in, iii, 29
Silurian Period, iii, 20, 191-4, 382;
animals and plants of, 252, 268, 274, 278, 282, 284;
limestones of, xii, 49;
species of, xv, 71
Silver, iii, 338;
affinity strength, viii, 128;
atomic weight and symbol, 383;
atomic weight determination, 308-9;
contraction on solidifying, iv, 150;
electrical conductivity, 283, vi, 80;
electric positiveness, 59;
extraction from ores, viii, 140, 170, 269, 270, 271-2;
fusibility, 384;
heat conductor, iv, 179;
in heavy metal group, viii, 126-7;
melting point and requirements, iv, 162;
metallurgy of, xvi, 176;
occurrence and uses, viii, 170-3, 198;
"parting" from gold, 272;
production, iii, 367-8;
recovered in copper refining, vii, 319, 320, viii, 272;
refining of, vii, 320;
specific gravity, viii, 384;
sterling, 171;
tarnishing of, 13, 77;
tests for, 286, 288
Silver Bromide, in photography, viii, 172
Silver Chloride, analysis, viii, 292;
in photography, 173
Silver Compounds, in photography, viii, 171-3
Silver Nitrate, uses, viii, 72, 146, 290
Silver-Plating, vii, 318-19, viii, 284
Silver Suboxide, viii, 97
Silver Sulphide, viii, 13, 170-1
Silver Thaw, i, 108, 381
Similarity, association by, xi, 197
Simon, Gustav, x, 131
Simoons, i, 134, 381
Simple Mechanical Powers, iv, 25

Simplon Tunnel, heat encountered in building of, iii, 121, xiv, 14;
length and altitude, 240, 241
Simpson, Dr. G. C., i, 93, 150
Simpson, Sir James, xvi, 185
Sims, Marion, x, 122, xvi, 186
Sin, disease as result of, x, 380
Sine Curves (electricity), vi, 201
Singers, range of, ix, 99;
vocal cords of, 83
Singer Sewing Machine, v, 285

Singing, development of art of, xv, 296, 312-15, 325;
of teakettle, iv, 167

Single-celled Animals, iii, 265 (see Unicellular Animals)

Single-celled Plants, xiii, 166, 167
Single-fluid Theory, vi, 288-93
Single-Phase, defined, vi, 201-3

Single-Phase Currents, advantages and disadvantages, vii, 196

Single-Phase Induction Motors, vi, 241, 250
Single Rail Cars, v, 342-3
Single-thread Sewing Machines, v, 285
Sink Hole Lakes, iii, 157
Sink Holes, iii, 127 (fig.), 128
Siphon, atmospheric pressure in, i, 25;
in ancient Egypt, xvi, 68
Siphonophores, xii, 37
Siren Whistle, iv, 205
Sirian Stars, ii, 115, 117;
distance and brightness, 353;
in galaxy, 122
Sirius, angular diameter, ii, 151;
binary system, 334;
brightness, 263, 295, 316;
color, 115, 296, 297;
companion of, 109;
composition, 115;
displacement in spectrum lines, 119;
distance and parallax, 315, 319;
distance increasing, 119-20;
in moving cluster system, 343;
magnitude, motion and type, 319;
origin of name, 302
Sirocco Winds, i, 134, 381
Sisal, ropes from, xiii, 10;
source of, 188, 240-1
Sitatungas, xii, 327
Sitka, climate of, xiv, 345
Sitka Spruce, in Pacific forests, 374
Sitting, right posture, importance of, ix, 57
(see also Sedentary Habits)
Size, effect on attention, xi, 344;
perception of, ix, 105;
physiological actions dependent on, 296, 347
Skaptar Jokull, i, 59
Skaters (bugs), xii, 114
Skates (fish), eggs of, xii, 140;
gill clefts in, 148
Skeletal Muscle, ix, 75-84;
breathing controlled by, 256-7;
contraction and relaxation, of, 164;
nerve connections of, 160, 162;
voluntary control of, 163
(see also Muscles)
Skeleton, of vertebrates, xii, 132;
weight of, iv, 13;
compared with apes, xv, 59;
bones of, ix, 59-71;
cartilage beginnings, 58;
connective tissue, 13, 71-2
Skeptics, Greek, xvi, 85

Skill, of artisans, past and present, v, 42, 46;
fineness of discrimination in, xi, 125-6;
origin in response processes, 45;
will in relation to, 263-4
(see also Proficiency)
Skim Milk, viii, 363

Skin, blood vessels of, how controlled, ix, 161, 163, 215, 216, 217;
body heat regulation through, 310-12, 314-16;
chilling of, effects, ix, 323;
cold and warmth spots, 93;
colors in different races and latitudes, xv, 36-7;
cuticle of, ix, 312-13;
development in black and white races, xv, 49-50;
dry feeling, i, 322;
effects of cold and wet on, x, 239;
electric insulator, vii, 247;
excretions of, ix, 314, x, 310-311;
exercise effects on, 303;
fear effects, xi, 131, 132;
flushing and paling of, ix, 161, 162, 163, 165, 215;
functions, 312-14, x, 310;
germ infection through, 198, 201-2;
growth of, ix, 47-8, 287, 312-13;
hyperemia in sleep, xi, 284, 289;
of Nordics and Iberians, xvi, 48, 49;
oiling of, in hot and cold climates, x, 311;
pain organs in, ix, 314;
pores of, 322;
protective structure, x, 201;
sebaceous glands, ix, 313-14, x, 310;
sense organs in, ix, 314 (see Contact senses);
structure and sensations, xi, 109-15, 164-6, 184;
sunlight effects, vii, 249;
suppressed emotion effects xi, 141-2;
temperature, i, 318;
temperature sensations in, ix, 93-4, 319-20;
touch sense of, 92
"Skin Friction," v, 191, 192
Skin Grafting, x, 183, 189
Skin Pain, xi, 117
Skins, as clothing, xv, 256, 257;
canoes and rafts of, 264;
use in ancient Egypt, xvi, 73
Skipping Silverfish, xii, 104
Skoda, Josef, x, 113, 115
Skolai Creek, Alaska, iii, 217
Skuas, xii, 264
Skull, Skulls, bones of, ix, 61-3;
bones in infants, 345;
measurement and classification of, xv, 42;
of apes and men compared, 42-3, 62;
of European races, xvi, 49, 50;
of primitive men, xv, 91, 93;
of various races, 41-3;
use for drinking vessels, 248
Skullcap, flowers, xiii, 201, 205
Skull Capacity, xv, 40;
in various men and races, 40-1;
of apes and men, 89, iii, 302-3;
of primitive man, 304, xv, 89, 94-5
Skull Index, xv, 42
Skunk Cabbage, xiii, 188, 350
Skunk, absence of fear, xi, 136;
luminous species, i, 347;
protective means, xv, 18, xii, 347, 348
Sky, colors, explanation, i, 164, 165-6;
in art, 105;
man's invasion of, v, 219-38;
shadows of mountains in, i, 169-70

Skyscrapers, as lightning protection, vii, 219;
in earthquakes, xiv, 343;
wind-thrust on, v, 194
Slag, viii, 157-8;
phosphate from, 280, 345
Slasher (weaving), v, 280
Slate, iii, 382;
metamorphic rock, xiv, 19;
origin and occurrence, iii, 372;
quarries in N.Y., 189

Slaughterhouse Waste, as fertilizer, viii, 280, 343

Slavery, social results of, xv, 376, 378-9
Slavo-Lettic Tongues, xv, 162
Slavonian Language, xv, 162
Slavs, in Alpine group, xvi, 49;
north and south, xv, 137
Sledges, in transportation, v, 214-15
Sleep, xi, 281-91;
autosuggestion and, 306;
causes and factors of, ix, 218-19;
hot baths and, 322;
heart rest in, 210;
life during, ix, 11-12, 17;
metabolism during, 282-3, x, 271;
mind activity in, xvi, 19;
nature and functions, xi, 281-91;
periodic breathing in, x, 340;
primitive conceptions of, xv, 328, 329, 332;
retardation of impulses in, xi, 20;
skin during, 110;
tea and, xiii, 227;
time spent in, ix, 80
Sleeping, of plants, xiii, 88-9, 113;
outdoor, x, 240

Sleeping Sickness, immunity and susceptibility to, xv, 49, 50, 51 (see African, European Sleeping Sickness)

Sleep-Walkers, xi, 286-7
Sleet, i, 107-8, 381;
glaze called, 373;
ice rain, 375
Sliding Elasticity, iv, 157-8
Sliding Friction, v, 203, 204, 207, 214-15
Slings, xv, 219-20

Slip Rings, of alternators, vi, 159, 177, 196-7

Slipher, astronomer, ii, 131, 147, 337, 363
Slivers, cotton, v, 272, 274
Slogans, effectiveness, xi, 332
Slot Machine, Hero's, xvi, 93
Sloths, xii, 282, 283
Slow Sand Filters, viii, 319-20
Slowworms, xii, 206
Slugs, xii, 69-70
Slums, infant mortality in, ix, 352
Smallpox, African superstition of, x, 285-6;
consumption from, 292;
early inoculation for, 100-1, 207;
eruption on uncovered surfaces, 254;
European epidemic of, 59-60;
first described by Rhazes, 32;
germ of, 200;
immunity to, 207;
prevention of, xv, 49;
racial susceptibility to, 50, 51;
vaccination discovery, x, 100-3, 207-8;
vaccination success, 217
Smeaton, on Watt's engine, v, 44
Smell (Sense), ix, 96-8, xi, 69, 77-82;
direction perception by, ix, 117, 120;
distance perception by, 121;
food-judging by, 95;
in fishes, xii, 139;
in insects, 101;
in infants, ix, 350-1;
nerve of, xi, 29-30;
photisms of, 222;
sense of, location, x, 341
Smellie, William, x, 104
Smelling, motions of, ix, 82-3
Smelting, v, 315-16, 317-18;
dependent on oxygen, i, 24;
history of processes, xvi, 174, 175, 176;
precipitation treaters in, vii, 348-51;
smoke from, 345, 346, 347
Smelts, xii, 154, 159
Smilax, leaves, xiii, 183 (fig.)
Smilax Family, xiii, 188
Smiling, psychology of, xi, 357
Smith, Prof. J. Warren, i, 246, 248, 253

Smith, William, geological work, iii, 15, 18, xvi, 126, 168-9

Smith River, Montana, xiv, 176

Smithsonian Astrophysical Observatory, ii, 186

Smithsonian Institution, i, weather observations, i, 215-16

Smoke, cause and prevention, vii, 343-5, viii, 45-6;
cloud and fog nucleus, i, 91, 94;
electrical precipitation, vi, 164, vii, 216, 301-2, 343, 346-51;
evils and war against, i, 63-5, viii, 304;
from fires, in air, i, 56-7;
from gunpowder, viii, 145;
in air, clearing of, ix, 269;
moor, i, 56;
nuisance and waste, vii, 345-6
Smokeless Powder, viii, 145, 260-1;
introduction, xvi, 163
Smoke Screens, phosphorus, viii, 87
Smoking, of foods, viii, 372
Smoking of Tobacco, xiii, 256;
cancer from, x, 120;
heartburn from, ix, 232
Smooth Muscle, ix, 74, 84-5;
adrenalin effects on, 171;
chemical control of, 167-9, 170, 336;
emotional control, 163-7, 168;
habit in operation of, 251;
nerve connection and control, 159-69;
occurrence in body, 160-2;
reflex control, 163
Smoothness, sensation of, xi, 128
Smuggled Goods, X-ray search for, vii, 256-7
Smyth, Piazza, ii, 141
Snails, iii, 260, 272, 272-3, xii, 68-71;
deep sea, 23;
flower fertilizers, xiii, 123, 144, 153;
in lakes, xiv, 211-12;
winged, xii, 19
Snakebird, xii, 253
Snake Hill, N. J., xiv, 110
Snake River, xiv, 174-5;
gorge of, xiv, 166
Snake River Valley, lavas of, iii, 228
Snakes, xii, 182, 211-38;
absence of fear, xi, 136;
ancient, iii, 295;
ancient, xii, 210;
egg-teeth of, xii, 205;
embryological resemblance, xv, 54;
in oceanic islands, xiv, 278;
poison of, xv, 18
Snapdragon, flowers of, xiii, 190, 201
Sneers, origin, xi, 133
Sneezing, in infants, ix, 349;
nervous mechanism, xi, 19, 20;
reflex action, ix, 135, 258
Snell, Willebrord, ii, 58
Sniffing, effect of, xi, 80;
purpose of, ix, 82-3, 96
Snipes, xii, 262-3
Snow, i, 114-17, 381;
forests and, xiv, 378;
freezing mixtures with, iv, 175;
from cloudless sky, i, 119;
glaciers and, iii, 59-60;
railroad problem, i, 267;
regelation of, iv, 166;
removal problem, i, 117;
water supply from, i, 118;
winter wheat and, 253
Snow Bins, i, 118, 381
Snow Clouds, i, 101, 102
Snow Crystals, i, 115-16
Snowdrops, flowers, xiii, 120
Snow-eater Winds, i, 133, 369
Snowfall, glaciers in relation to, xiv, 54-5;
heaviest in U. S., i, 118-19;
measurement, 79-80, 118, xiv, 351
(see also Precipitation)
Snowfall Charts, i, 206
Snowflakes, i, 115;
clouds of, 92-3, 103;
fogs of, 95
Snow Fleas, xii, 104
Snow Line, iii, 59;
in tropics and arctic, xv, 72-3;
on mountains, iv, 183-4
Snowstorms, St. Elmo's Fire in, i, 157, 158
Snow Surveys, i, 118, 382
Snubbing Posts, friction on ropes on, iv, 94
Soap, chemistry of, viii, 141-3, 221;
hard water effects, viii, 143, 152, 322, xiv, 147;
use of, in bathing, ix, 313, 314, x, 311
Soap Bubbles, iridescence of, xii, 245
Soap Films, colors of, iv, 377, xii, 245
Soapstone, iii, 339-40
Sobieski, John, xiv, 308-9
Sobrero, nitroglycerine, xvi, 163
Social Classes, rise of, xv, 375-8
Social Evolution, xv, 29-31

Social Institutions, crowd psychology in, xi, 333;
development of, xv, 29-31, 383-4

Socialism, theories of, xv, 377-8

Social Workers, in treatment of disease, x, 383

Society, dominant impulses in, xv, 185;
habit and stability of, xi, 255-6;
language the product of, xv, 142
Sociology, concrete science, xvi, 42;
least positive science, x, 368;
medicine and, 369
Socrates, killed by hemlock, xiii, 250;
on essential forms, xvi, 87
Soda, deposits of, viii, 275
Soda Ash, viii, 135
Soda Lakes, xiv, 206, 212
Soda Pulp, v, 294
Sodium, affinity intensity, viii, 128;
affinity for chlorine, 120;
alkali metal, 132;
atomic weight and symbol, 383;
electrolytic production, vii, 320-1, viii, 284;
extraction by electrolysis, 271;
flame color, 134, 301;
fusibility, 384;
in body tissues, 354;
in earth's crust, iii, 308, viii, 19, 129, 148, 192, 195;
metallic nature, 17, 127, 181;
plant needs of, 337, 341;
properties, 133-4;
source of industrial, 275;
specific gravity, 384;
spectrum of, iv, 362, viii, 301;
test for, 287, 289
Sodium Acetate, electrolysis of, viii, 266
Sodium Bicarbonate, viii, 136
Sodium Borate, viii, 141 (see Borax)
Sodium Carbonate, viii, 116;
manufacture of, 276-8;
occurrence in nature, 189, 197;
uses, 135, 146
Sodium Chloride, viii, 138-40;
electrolysis of, 124-5;
ionization in solution, 123, 301;
in urine, x, 343;
pure, xiv, 296;
stability of, viii, 120
(see also Common Salt)
Sodium Compounds, viii, 134-43;
flame color, 301;
in sea, 138, 196, 279;
replacing potassium, 133-4, 144;
uses, 146
Sodium Cyanide, viii, 141
Sodium Feldspar, viii, 90
Sodium Hydrogen Carbonate, viii, 135-6
Sodium Hydrogen Sulphate, viii, 83, 116, 137
Sodium Hydroxide, viii, 134-5;
normal solution, 119;
preparation of, 276, 278, 284;
uses, 135, 141, 142, 221, 255

Sodium Hypochlorite, as antiseptic, x, 146, 181;
preparation, viii, 284
Sodium Iodide, solubility, viii, 112
Sodium Light, colors in, iv, 365
Sodium Nitrate, viii, 137-8;
Chilean deposits, 64, 72, 197, 280
Sodium Nitrite, viii, 141
Sodium Peroxide, viii, 134
Sodium Phosphate, viii, 89, 141
Sodium Silicate, viii, 141
Sodium Stearate, viii, 143, 221
Sodium Sulphate, viii, 83, 116, 137;
electrolysis of, 125
Sodium Sulphite, viii, 117, 140, 146, 372
Sodium Thiosulphate, viii, 140-1, 172
Soffioni, steam jets, v, 179
Soft Coal, combustion, viii, 45;
composition, 252;
conversion into coke, 46, 252;
distillation and products, 252-4;
origin, xiii, 10

Soft Foods, for children, remarks on, x, 314, 315

Softness, sensation of, xi, 128
Soft Soap, making of, viii, 142
Soil, iii, 382;
acid conditions and correction, viii, 346-7;
air in, xiii, 92;
alluvial, xiv, 70-1;
bacteria in, xiii, 98;
clay in, iii, 27-8, xiv, 137;
conservation necessity, 64;
constituents necessary to plants, viii, 341-6, xiv, 64-5, 66-8;
depths of, iii, 26, xiv, 64;
enrichment by nitrogen plants, xiii, 98;
fertilization by lightning, i, 153;
forest protection of, xiv, 379;
formation and nature, iii, 26-8, 32 (illus.), viii, 191, 195, 338-41, 347, xiv, 63-4, 68-9;
glacial, iii, 67, xiv, 69-70;
holding of, by plant roots, xiii, 19;
liming of, viii, 150, 346-7;
loess (see Loess);
of arid regions, xiii, 381, xiv, 68-9;
rainfall effects on constituents, 69;
residual, iii, 26-7, xiv, 68;
restoration of, viii, 341-6, 347, xiv, 66-8, 69

(see also Fertilizers);
sewage application to, viii, 327;
traveled, xiv, 63, 69-75;
vegetation determined by, xiii, 382, xiv, 363-4;
volcanic, 69, 329

(see also Lava Soils);
wind carrying of, i, 53-4, iii, 71, 73-4, xiv, 71-5

Soil Water, absorption by plants, xiii, 91-3;
erosive depths, xvi, 173;
plant materials in, ix, 26, 29;
rise of, viii, 37
(see also Ground Water)
Solar Apex, ii, 305
Solar Constant, iv, 194
Solar Day, iv, 16
Solar Eclipses, ii, 209-18;
corona seen only in, 219;
death of Domitian announced, 221;
difficulty of observing, 219;
Einstein theory tested by, 81-2;
first accurate prediction, 27;
necessary interval between, ii, 224;
Hally's observations, 87;
Hipparchus's discoveries, 32;
prominences observed in, 179, 180;
records of, in ancient China, 21-2;
restricted areas, 207
Solar Engines, ii, 169-70

Solar Spectrum, ii, 111-12, 114, iv, 358-9, 362, 365-7;
lines, how produced, ii, 184;
photography, 128
Solar Stars, ii, 115;
distance, 353;
distribution, 122, 354;
planetary systems, 252
Solar System, bodies and motions, ii, 162-4;
brief description, iii, 158-9;
identity with atomic, vi, 115;
motions accounted for by Newton, ii, 67, 73;
movement toward Hercules, xvi, 124-5;
movement toward Lyra, ii, 122, 137, 305-6;
position in universe, 353-4;
sun as center (see Heliocentric System);
theories of formation, 366-81, iii, 159-63;
unit of measurements, ii, 315
Solar Tides, xiv, 292

Solder, tin and lead in, viii, 161-2, iv, 161-2

Soldering, alloys used for, iv, 161-2
Soldier Beetles, rains of larvæ, i, 356
Soldiers, asleep on march, xi, 286-7;
crowd psychology in battle, 326-7;
crossing of bridges by bodies of, iv, 225;
fatigue relieved by music, x, 247;
lack of choice in, xi, 260-1;
sense of pain in, 119-20;
shoes of, ix, 69
Solenoid, iv, 286-7, vii, 375
Solfatara, volcano, v, 180

Solidification, expansion on, iv, 149, 150-1, 163;
heat of, 160, 161, 188;
suspended, viii, 113, 304-5
Solidism, doctrine of, x, 25-6, 28

Solidity, perception of, ix, 119-20, xi, 173-83

Solids, chemical properties, viii, 297-301;
distinguished by pressure, iv, 22-3;
elasticity of, 156;
expansion coefficient of, 145;
heat conduction by, 176-7;
heat effects on, 144, 152, viii, 25;
melting of (see Melting);
molecules in, iii, 309, iv, 22, 131, 152, 363, viii, 24;
solutions in water, 112-13;
sound velocity in, iv, 198;
spectra of incandescent, ii, 112, iv, 360, 363;
vibration of, 215
Solitaire (bird), xii, 269
Solomon, wives of, xv, 289
Solomon's Seal, rootstalk, xiii, 22 (fig.)

Solstices, observed in ancient times, ii, 25-6

Solute, defined, viii, 382
Solutions, viii, 111;
boiling point and freezing point, 299-30;
chemical reactions in, 37;
colloidal, 314-16;
heat and cold production by, iv, 175;
ionization of, viii, 119-25;
molar, 118-19, 379;
molecular action in, 113, 311;
normal, 119, 379-80;
of gases, liquids and solids in water, 111-13;
osmotic pressure in, 113, 311, xvi, 164;
overheated, viii, 304;
properties of, summarized, 311-12;
specific gravity of, 313;
vapor pressure of, 305
Solutrian Implements, xv, 100, 105, 109
Solvay Process, viii, 276, 277-8
Solvent Action, of water, viii, 111-12;
heat and, 112
Solvents, esters as, viii, 221;
water, alcohol and ether, 217
Somaliland, antelopes of, xii, 327
Somme River, changes in, xiv, 184
Somnambulism, xi, 286-7
Song Birds, xii, 268-9
Songs, primitive, xv, 312-13, 314, 319-21
Sonic Wave Transmission, v, 108
Sonnblick, St. Elmo's Fire, i, 157, 158
Sonora Earthquake, xiv, 334
Soot, i, 52;
deposits, 64, 65;
formation of, viii, 45
Sophists, Greek, xvi, 87
Soranus of Ephesus, x, 26
Soreness, muscle, ix, 80-1
Sore Throat, cause, x, 253;
from colds, 253;
from infection of tonsils, ix, 187
Sorghum Molasses, viii, 243
Sori, of plants, xiii, 64, 155
Souder, Wilmer H., iv, 237

Soul, and body (Hindoo belief), ix, 11-12, 17;
meaning of, xi, 382;
primitive conceptions of, xv, 328-32;
source of vital movement, (Stahl), x, 84;
Thales on universal, xvi, 76;
universal belief in, 44
Soule, Samuel W., v, 312

Sound, Sounds, analysis and synthesis of, iv, 52, 233-4;
atmospheric effects, i, 187;
audibility, distances and variations in, 187-92;
audibility in rain, 187;
audibility (vibration limits), iv, 204;
colored hearing, xi, 222;
dense atmosphere effects on, iv, 31-2;
distance, how estimated, i, 187;
emotions stirred by different kinds, iv, 51-2;
intensity and loudness, 211-12;
interference of, 218-22;
kinds and qualities, xi, 104-8;
motor response, 103;
"musician" of physics, iv, 50;
perception of, by ear, 203-4, 211-12, ix, 99, 100, 103;
perception of direction and distances by, 117, 121, xi, 167-9;
pitch of, (see Pitch);
production, iv, 195-7, ix, 98;
quality of, iv, 232-5;
resonance, 226-32;
shadows, 236;
simple and compound, 213-17;
transmission, i, 186, iv, 195-201, ix, 98-9;
transmission by water, v, 107, 108;
velocity, i, 186-7, iv, 198-9, 200, 201, vii, 210;
wave theory of, iv, 52;
wind effects on, 210-11
(see also Acoustics)
Sounding Balloons, i, 20-1, 382;
heights reached, 22
Soundings, ocean, xiv, 23-4, 284
Sound-ranging, i, 313;
in World War, 201-2
Sound Waves, diffraction of, iv, 52, 236-7;
Doppler's principle, ii, 119, iv, 209-10;
effect on ear, ix, 99, 100, xi, 99-101;
energy, on what dependent, iv, 211;
formation and transmission, 196-201;
frequency and length, 204, 236;
from Krakatoa eruption, i, 188, xiv, 324;
interferences of, iv, 218-19, vii, 279;
interferences in thunder, i, 193;
machine to respond to, v, 331;
mechanical reproduction of, iv, 240;
number, amplitude, and forms, xi, 104-5;
passage through orifices, iv, 236;
photographic records of, 52, 233-4, 237;
power transmission by, v, 107-8;
reflection and refraction of, iv, 236-40;
simple and complex, 213-17;
transmission, i, 186, iv, 196-201, ix, 98-9;
visible, (flashing arcs) i, 194, 372
Soups, value of, at meals, ix, 241, x, 320
Sour, taste of, ix, 95, xi, 70, 71, 72
Sour Disposition, xi, 55
Souring, lactic acid in, viii, 223
Sourland Mountains, xiv, 111-12
Sour Milk, longevity and, xiii, 172
Soursops, origin, xiii, 226
South Africa, ancient reptiles of, xii, 184;
animals of, 281, 304, 327-8, 345, 348, 360;
bushmen of (see Bushmen);
climate of, xiv, 224;
cobras of, xii, 226, 227;
diamond mines, iii, 328;
duet whirlwinds, i, 60;
glacial and coal deposits, iii, 203, 204;
gold production, 365, 367;
kopjes of, xiv, 82;
no weather maps, i, 230;
rodents of, xii, 289, 290;
spurges, xiii, 28-9;
stock-raising in, xiv, 384
South Aldabra, tortoise of, xii, 191

South America, animals (herbivora), xii, 275, 276, 282, 283-4, 289, 306, 313;
animals (carnivora), 342, 360-2, 363, 364;
antiquity of, 282;
birds of, 241, 251, 256, 266;
climate on east and west coasts, xiv, 305;
coasts iii, 57, xiv, 25-6, 247-8, 250, 251;
coasts, coral reefs on, xii, 40;
coffee in, xiii, 232;
drainage systems, xiv, 190;
fish of, xii, 159-60, 166;
former connection with Antarctica, xiv, 290;
former submergence, iii, 216;
indigenous plants, xiv, 382;
meteorological backwardness, i, 218, 230;
monkeys of, xii, 377;
plains of, xiv, 218
(see also Pampas);
plateaus of, 222;
potato in, xiii, 218;
reptiles, xii, 198, 208;
river connections, xiv, 187;
"scrub" vegetation of, 379;
snakes of, xii, 213, 215-16, 221;
temperate forests of, xiv, 371, 382;
tobacco used by natives, xiii, 256;
west coast harbors, xiv, 265

South American Indian, acclimatization of, xiv, 356;
blow gun of, xv, 216, 217 (fig.);
foot-plow of, 236 (fig.);
long bow of, 213 (fig.);
weapons of, 216, 219

South Atlantic Ocean, temperature of, xiv, 297

South Carolina, tin production, iii, 368

South Dakota, bad lands of, xiv, 81 (see Bad Lands);
high temperature, i, 209;
loess deposits, xiv, 72;
"Sunshine State," i, 86;
tin production, iii, 368
Southern Cross (stone), xv, 103
Southern Forest, (U. S.), xiv, 372-3

Southern Hemisphere, climates insular, xiv, 346;
deflection of motion in, i, 125, xiv, 348;
land in, 20;
temperate forests of, 371, 382;
tides in, 292;
winds of, i, 125, 127-8, xiv, 345-6, 348
South Pole, rain at,
(see also Antarctica) i, 109
South Sea Islanders, xv, 9;
chiefs, how chosen, 364;
ideas of morality, 254;
plaited mats of, 243;
writing venerated by, 164;
words derived from, 161
South Sea Islands, atolls of, xii, 41;
snakes absent from, 217
Sowerby, James, xvi, 170
Spa, Belgium, xiv, 145

Space, absolute and relative, ii, 80, iv, 16-17;
æther of (see Æther);
heat transmission through, iv, 180-4;
infinity of, xi, 191, 196;
interplanetary, air absent, i, 186;
perception of, xi, 162-91;
primary concept, iv, 14, 15;
relativity of, xvi, 196-8;
temperature of outer, vi, 270;
time compared with, xi, 192
Spadix, of arums, xiii, 188
Spain, Arab astronomy in, ii, 38;
buffaloes in, xii, 329;
callina, i, 96;
cattle of, xii, 330;
coast formations, iii, 57, xiv, 46-7, 249, 257;
conquests in America, 310;
Cro-Magnons in, xv, 102;
desiccation of, xiv, 379;
esparto grass, v, 292;
formerly peninsula of Africa, xiv, 291;
lynx of, xii, 365;
metal production, iii, 360, 362, 370, xiv, 237-8;

Moorish science, xvi, 100, 106;
potash deposits, xiv, 68, 209;
Pyrenees Mts., as protection of, 239-40;
rainfall of, 358;
solar eclipses, ii, 215-16;
toads of, xii, 176
Spallanzani, Lazaro, x, 88, 139, xv, 114
Spalling, of stones, iii, 24

Spanish-American War, searchlights at Santiago, iv, 352;
typhoid fever in, x, 286;
weather service in, i, 309
Spanish Armada, xiv, 280;
weather importance, i, 307
Spanish Bayonet, xiii, 183
Spanish Fly, x, 111

Spanish Language, descent from Latin, xv, 160, 162

Spare Diet, remarks on, xi, 370

Spark Gaps, in wireless installations, vii, 263, 264, 271-2, 287

Sparking, of electric machines, 375;
potential tables, 383
Sparrows, increase in U. S., xv, 21
Spathe, of arums, xiii, 188
Spawn, of mushrooms, xiii, 164
Speaking Trumpets, iv, 239-40
Spear-throwers, xv, 212 (fig.), 213
Spears, xv, 208-10

Specialization, in civilization, xv, 131-2, 203

Specializing, in science, x, 43
Species, xii, 28, xiii, 170, 329-30;
chromosome numbers in different, ix, 46;
climate effects, on, xvi, 141;
continuity dependent on heredity, xiii, 326;
crossing of (plants), 147;
distribution studies, xvi, 140;
establishment of new, 158;
evolution of, iii, 18, 260-1;
extinction of, 261 (6), 293, xiii, 323;
geological epochs determined by iii, 19;
number in relation to latitude, xiv, 366;
number of plant, xiii, 323;
origin, Darwinian theory, x, 135, xvi, 150-2

(see also Mutation, Variation, Natural Selection);
permanence theory, xvi, 150;
types and, xiii, 356
Specific, technical meaning, iv, 109, 383
Specific Density, iv, 111, 112, 113
Specific Diseases, x, 196
Specific Gravity, iv, 109, viii, 381;
atomic weight and, 313;
discovery by Archimedes, xvi, 89;
methods of determining, iv, 111-13;
mineral identification by, iii, 321-41, viii, 202-3, 313;
of earth, xiv, 11;
of metals (table), viii, 384;
of solutions, 296, 813;
of various substances, iv, 109-10
(see also Density)

Specific Heat, iv, 109, 155-6, viii, 308-9, 382;
of water, 37
Specific Nerve Energy, doctrine of, x, 118
Specifics, medicinal, x, 49-50, 75
Specter of Brocken, i, 184-5, 382
Spectral Types (stars), ii, 115-18, 307-10;
absolute magnitudes and, 317;
binary periods and, 310, 334;
of star clusters, 343-4;
of star streams, 347, 348;
planetary systems and, 252;
solar apex and, 305-6;
speed of, 153
Spectrobolometer, ii, 128, 186
Spectrographs, at Mt. Wilson, ii, 154-5
Spectroheliograph, ii, 129, 183;
in work on sun, 176, 179;
of Mt. Wilson, 148, 154
Spectroscope, ii, 111, viii, 301;
astronomical applications, ii, 17-18, 112-24, 181;
chemical analysis by, viii, 301-2
Spectroscopic Binaries, ii, 122-4
Spectroscopic Parallaxes, ii, 153

Spectrum, Spectra, colors and lines of, ii, 111-12, 113, iv, 358-63, 365-7;
displacement of lines, ii, 119, 120, 121;
displacement of lines to test Einstein theory, 82;
intensity of lines, 124;
interceptions by atmospheric ozone, i, 16;
of airlight, ii, 181;
of aurora, i, 161;
of alkali metals, viii, 133, 147, 301;
of chemical elements, 183, 301-2;
of nebulæ, ii, 357, 359;
of new stars, 332-333;
of stars, 115-18, 119, 123;
of suns' corona, 211, 212, 223, 225;
of sun-spots, 177;
of vapors in magnetic field, 178;
of variable stars, 325, 326, 329;
used in measuring star distances, 153-4, 318;
X-ray, viii, 183, 309
(see also Solar Spectrum)
Spectrum Analysis, ii, 113-24, viii, 301-2;
discovered by Kirchhoff, ii, 17
Spectrum Colors, eye receptors of, xi, 89-90
Speculum, defined, vi, 102

Speech, advantages over sign language, xv, 151-2;
dense atmosphere effects on, iv, 32;
emphasis importance in, xv, 144-5;
evolution of, 152-4;
physical factors of, ix, 83;
power of, in man and animals, xv, 68, 91, 141

Speech Organs, tendency to respond to sound, xi, 103

Speed, perception of, xi, 165 (see Velocity)
Speed Boats, vi, 192
Spelling, English, xv, 176-8

Spencer, Herbert, evolution taught by, x, 136;
on education, 282, 284;
on evolution, xvi, 152;
on origin of priests, xv, 350;
on relativity of knowledge, xvi, 195-6
Spermaceti, xii, 299
Spermatozoön, origin of energy, xvi, 145

Sperm Cells, production and development of, ix, 332-3, 335, 339

Sperm-Whale, xii, 298-9
Sperry, Elmer A., v, 343
Sphagnum Moss, xiii, 69, 160-3, 166
Sphalerite, iii, 339, 363, 364
Sphincter Muscles, ix, 85;
fear effects on, xi, 132;
of stomach, ix, 231, 232, 233, 234, 236-8;
operation, xi, 37-9
Sphinx, erosion of, iii, 73
Spice Bush, xiii, 196, 351
Spices, xiii, 259-65;
effects on stomach, ix, 243-4;
food value, viii, 366;
in preserving, 372;
sensation from, ix, 98
Spiders, xii, 90-7
Spiegeleisen, v, 320
Spike, flower form, xiii, 50;
of grasses, 181
Spinach, origin, xiii, 223-4
Spinal Column, ix, 64 (fig.), 65;
in infants, xv, 81;
in man and apes, 57-8;
in vertebrates, 55-6;
ligaments of, ix, 71;
notochord of, xii, 128
Spinal Cord, ix, 131, 133 (fig.), xi, 25-7;
inflammations, cause of, x, 224;
medulla of xi, 28;
nerve connections through, ix, 130 (fig.);
neurones, xi, 21
Spinal Nerves, ix, 131-2, xi, 25-6
Spindles, ancient, xv, 244, 245 (fig.)
Spine, tuberculosis of, x, 92
Spinning, by Lake Dwellers, v, 14;
historical development of, xv, 243-4, 246
Spinning Jenny, invention, xv, 246
Spinning Machines, v, 273, 274-6, 376, 378
Spinning Wheels, v, 268, 273, 274;
development of, xv, 244
Spinosa, philosophy of, xvi, 117
Spinosity, in animals, iii, 277
Spiral Gears, v, 38-9

Spiral Hypothesis (see Planetesimal Hypothesis)

Spiral Nebulæ, ii, 361-5;
discovery, 17, 106, 186, 380;
distances, 124;
distribution, 355, 356;
globular clusters and, 337;
Jeans on origin, 378;
new stars in, 333;
new universes, 381;
origin, planetesimal theory, 372-4, iii, 160-2;
star streaming and, ii, 348-9;
studies at Mt. Wilson, 157-8;
transition from nebula to star, 136
Spirilli (bacteria), x, 195

Spirits, savage belief in, xv, 331, 332, 337-40, 348-9, 350, 358

Spirits of Wine, viii, 213-14
Spirometer, x, 339
Spitball, effectiveness of, iv, 69
Spitting, indiscriminate, x, 291
Spitting Adders, xii, 227
Spitzbergen, coal deposits, i, 199;
flora of, xiii, 341-2;
ice-caps of, iii, 61
Splanchnic Nerve, xi, 273
Spleen, functions of, ix, 184, 275
Split-Phase Starters, vi, 250
Spoken Language, evolution of, xv, 152-4
Sponges, iii, 259, 266, xii, 23, 30-2
Spongin, xii, 31
Spontaneous Combustion, viii, 55-6
Spontaneous Generation, x, 139;
history of doctrine, xvi, 114;
origin of life by, xii, 10
Spoonbills, xii, 151, 256
Sporangia, xiii, 155

Spore-habit, relics in cycads and ginkgo tree, xiii, 309, 316

Spores, xiii, 64;
dispersal by winds, 344;
fermentation by, viii, 248;
in atmosphere, i, 61;
of anthrax bacillus, x, 149;
of ferns, xiii, 155-7, 159, 160;
of moss, 69, 162;
of mushrooms, 163, 164
Sporogony, x, 159
Sports (mutants), ix, 342, xiii, 333-4
Sporulation, x, 155
Spotted Fever, cause of, xii, 98
Sprague, F. J., vi, 26
Spring, frosts, i, 257-8;
rate of advance in U. S., i, 256
Spring Balance, iv, 58-9, 102
Springboks, xii, 327
Springhaas, xii, 289
Springs, iii, 116-17, xiv, 137-9;
drying of, 136;
fissure, 138, 152;
fluctuations and constancy, 152;
forests and, 379;
Havana water supply from, 140;
hillside, 137-8;
in river formation, 175-6;
in western canyons, iii, 116;
"juvenile," xiv, 151-2;
lacking in clay soils, 137;
mineral matter in, viii, 195
(see also Hot Springs, Mineral springs)

Springs (mechanics), air-cushioning of, v, 134;
energy of, iv, 82, 87-8;
pneumatic, v, 126;
storage of energy in, 126
Spring-tails, xii, 104
Spring Tides, ii, 70, xiv, 292
Spruce, traveler, i, 352
Spruce Forests, xiii, 367-8;
in relation to winds, 149
Spruce Trees, dominance in north, xiii, 350;
in northern forests, xiv, 372, 374;
nativity, xiii, 244;
paper pulp from v, 292, 293, xiii, 10, 234, 244;
planting conditions, 270;
polycotyledons, 61;
roots, 17
(see also Conifers)
Sprudel Spring, xiv, 152
Spur Gears, v, 29
Spurges, antiquity, xiii, 324-5;
South Africa, 355, 379;
rubber from, 249;
stems, 28-9, 30-1

Sputum, tuberculosis spread by, x, 291, 292, 293-4

Squalls, i, 382
Squash, origin, xiii, 224
Squaw Winter, i, 361, 382
Squids, xii, 79-80;
deep sea, 23;
phosphorescence of, 20;
whales and, 299
Squirrel-cage Induction Motors, vi, 245;
on farms, vii, 224
Squirrels, xii, 291-4;
antiquity of, 286;
arboreal habits, 285;
man's lesson from, xv, 206;
storing of fruits by, xiii, 56, 340;
sugar, xii, 278
Stabilizers, gyroscopic, v, 341-2
Staffa, hexagonal columns of, xiv, 129, 130
Stags, xii, 317;
age of, xv, 100 (fig.)
Stahl, George Ernst, x, 84-5, 301

Stained-glass Windows, preparation of designs for, iv, 342

Stalactites and Stalagmites, iii, 127, viii, 151, xiv, 148;
rate of formation, xv, 79-80
Stalks, of plants, xiii, 27
Stalling, of motors, v, 157
Stamens, xiii, 45, 46;
arrangement in various flowers, 123-46, 181-207;
in grasses, 182;
of highly cultivated plants, 51;
in reproduction, 117, 119, 120, 121, 122
Staminate Flowers, xiii, 46-7
Stamping, of feet, in excitement, xi, 356
Standard, of flowers, xiii, 47-8
Standard Barometer, iv, 119-23

Standardization, in manufactures, v, 48-52, 53-4, 55-6

Standing, correct posture in, ix, 57, x, 305;
heart beat in, ix, 207

Stanley, Henry M., African trip, xiii, 359, 361

Staphylococci, x, 195
Star Anise, origin, xiii, 255
Star Apples, origin, xiii, 227

Starch, composition and properties, viii, 227-8;
digestion of, 357, ix, 230, 235, 242, 292, x, 270, 326, 330;
fermentation, viii, 225, 248, 249;
food value, 365, ix, 300, x, 259, 262, 269, 271

(see also Carbohydrates);
food amounts in ordinary diet, ix, 290, 300-1;
foods for infants, 346;
glucose production from, viii, 225, 228, 241, 243-4;
iodine effects, 228, 294;
made from rice, xiii, 213;
making of, by plants, viii, 335, 349, ix, 27-8, 28-9, xiii, 79, 80, 83-4, xiv, 65;
manufacture and uses, viii, 243;
tastelessness of, 366
Star Charts and Catalogues, ii, 298-9, 300-3;
early, 29, 31, 34, 39, 45, xvi, 90,
(see also Draper Catalogue)
Star Classification, by color, ii, 296-8;
by giant and dwarf theory, 309;
by magnitude, 295-6, 297;
by spectra, 115-18, 307-10;
by temperature changes, 309-10
Star Clouds, ii, 357-60
Star Clusters, ii, 122, 336-40;
moving, 341-4;
nebulæ and, 357;
photography of, 136
Star Distances, ii, 311-18;
ancient ideas, 28, 350;
brightness in relation to, 322;
first measurement, 16;
methods of measuring, 124, 153, 311-13, 316-18;
of Galaxy, 355;
of globular clusters, 337, 338-9, 340;
of nebulæ, 358;
of spiral nebulæ, 363;
of Sirians and Solars, 122, 353;
unit of measurement, 315-16, xvi, 33-4

Star Distribution, ancient and modern conceptions, ii, 350, 352-3;

Galaxy as basis, 350, 351, 352, 353, 354, 364-5;
globular clusters, 338, 339

Starfishes, iii, 259, 268, 269, 270, xii, 49-50

Star Flowers, xiii, 203
Starling, Prof., quoted, xi, 154, 182;
secretin discovery, x, 325
Stars, aberration orbits, ii, 90-1, 92;
actual dimensions, 321-4;
angular diameters, 150-1;
brightness (see Magnitude of Stars);
Classification (see Star Classification);
constitution, 382-3;
constitution determined by spectra, 17, 113, 114-18;
distances (see Star Distances);
distribution (see Star Distribution);
evolution order, 116-17, 308-9, 310, 383;
evolution seen in spiral nebulæ, 362;
giant and dwarf, 153, 294, 309, 310, 382-4;
light, 296, 16;
light-intensity, vi, 272;
light of, in space, iv, 334;
magnetism, ii, 178;
magnitudes (see Magnitude of Stars);
motions (see Motus Peculiaris, Proper Motion, Star Streams);
multiple, 335;
naming of, 302-3;
nearest, 319-20;
nebulæ and, 308-9, 365, 381;
nebulous, 360;
new or temporary (see Novae);
number, 294-5;
origin, Jeans on, 378-9;
parallax (see Parallax);
photography in study of, 135, 137;
planets of, 252-3;
radiant energy, 384;
radiative equilibrium, 383-4;
right ascension and declination, 299, 305;
spectral type, 115-18, 307-10;
spectra affected by atmospheric ozone, i, 16;
transit measurement by eye-and-ear method, xi, 155-6;
twinkling, to what due, i, 174;
universe of, ii, 294-9;
variable (see Variable Stars);
worship in ancient Egypt, 24;
why unseen by day, i, 164
Star Streaming, ii, 306, 317, 345, 347;
Jeans on origin, 378
Star Streams, ii, 345-9;
nearest stars in, 320

Starters, automobile, vii, 120, 127, 135, 142-8;
of motors, vi, 236-9, 250-5, 262-3
Starvation, x, 275;
diabetes treatment by, ix, 294;
sense of hunger in, 88;
waste of tissues in, 297-8;
weight reduction by, 302

Stassfurt Deposits, viii, 196, 278-9, 344, xiv, 67, 209

States of Aggregation, iv, 22
States of Matter (see Physical State)
Static, technical meaning, iv, 383
Static, in wireless (see Strays)
Static Breeze, vii, 238-9

Static Electricity, iv, 259, vi, 284-305, vii, 375;
lightning as, 205, 206, 207-9
Static Generators, vii, 245
Static Induction Machine, vii, 236
Static Sense, xi, 126
Statics, defined, iv, 25, 383;
early development of, 25, 27
Stationary Waves, iv, 217
Statue of Liberty, lighting, vi, 283
Statues, coloring of, xv, 300, 302;
primitive, 118, 120
Stature, artificial selection, xvi, 154, 157;
in relation to food, xiii, 172;
of various European groups, xvi, 48, 49;
of various races, xv, 38-9;
rate of growth in man, ix, 32 (diagram)
Steam, density of, iv, 113;
dry and wet, v, 140;
exhaust, vi, 355;
invisibility of true, i, 90;
latent heat of, iv, 188, v, 354, viii, 38;
saturated and superheated, v, 140;
saturated, pressure of, iv, 168;
specific heat of, 155, 187;
specific heat ratio, iv, 156;
use in engine and turbine, v, 142
Steamboats, early, v, 189-90, 192, 377;
early dangers, i, 49-50
Steam Boilers (see Boilers)
Steam Carriages, v, 207-8, 212
Steam Electric Plants, vi, 351, 353-61;
size of generating units, 378-9

Steam Engines, efficiency, on what dependent, iv, 192;
estimate of work of, 193-4;
history and principles, v, 139-48, 376;
in power plants, vi, 354-5, 357-8;
invention and consequences, xvi, 125, 126;
origin in kitchen, v, 109;
reciprocating compared with turbine, 152-4;
starting of, vi, 235;
temperature and pressures in, v, 139-40;
waste of heat energy, 155;
Watt's, 44, 47, 144-6, 376, 377
Steam Hammer, invention, xvi, 175;
Nasmyth's, v, 379
Steam Heat, dryness of air from, xiv, 353
Steam Heating System, iv, 186-7, xiv, 353

Steam Navigation, development, v, 189-90, 192-4

Steam Power, disadvantages in mining, v, 128-9;
from subterranean heat, 180-1;
from sun's heat, 177-8;
from volcanoes, 179-80;
waste of heat energy, 155
Steam Reserve, of power plants, vi, 367

Steamships, development of ocean, v, 192-4, 378;
glass-enclosed machinery, vi, 175;
propellers (see Propellers);
speed, power and lines, v, 191-2;
turbines on, 105, 153
(see also Ocean Steamers)
Steam Shovels, v, 252-3, 262
Steam Traction, beginnings, v, 207-8, 212
Steam Turbines, v, 148-54, 382, vi, 354-5;
connection with ship propellers, v, 105-6, 153-4, vii, 329-30;
efficiency, v, 155, 172;
Hero's, xvi, 92, 93;
most efficient speed, vii, 329;
speed-limiting device, 49;
use of steam in, v, 142
Stearic Acid, viii, 220, 221, 350
Stearin, glycerine from, viii, 247
Steatite, iii, 339
Stebbins, astronomer, ii, 212, 328
Steel, alloys of, xiv, 238;
composition and properties, viii, 159-60;
cutting of, vii, 321;
elasticity of, iv, 36;
expansion by heat, 145, v, 71;
magnetism of, iv, 245, 251, vi, 36-8;
purification in electric furnaces, vii, 304;
structure of hard and soft, iv, 37;
silicon in, viii, 90
(see also Steel Making)
Steel Engravings, by electrotype, vii, 314

Steel Making, v, 319-25, 380, 383, viii, 159-60, 273, xvi, 174-5;
electric furnace in, vii, 301, 305, 312;
phosphorus obtained from, viii, 345
Steel Mills, electromagnets in, vi, 35, 86;
great motors, 228-9;
rise of body temperature in, ix, 317

Steel Rails, electric furnace steel for, vii, 312;
expansion by heat, iv, 134;
friction, v, 204, 206;
manufacture, 322-3
Steel Shipments, meteorology in, i, 269
Steel Ships, v, 195;
compass variations in, iv, 254, v, 340, vi, 42

Steel Structures, electrolytic corrosion, vi, 64-6;
in earthquakes, xiv, 343
Steel Tracks, for trucks, v, 206-7
Steenheil, K. A., xvi, 191
Stegocephalia, xii, 168
Stegosaurs, iii, 289-90
Steinboks, xii, 326, 327
Steinmetz, C. P., vi, 26
Stejneger, Dr. Leonard, xii, 226, 234
Stems of Plants, xiii, 22-32;
acting as leaves, 28-31, 378, 379;
chlorophyll in, ix, 26;
of grasses and sedges, xiii, 179, 182 (fig.), 183;
purposes, 61;
response to light, 85;
roots from injured, 19;
starch and sugar storage in, ix, 27-8;
upheld by osmotic pressure, xiii, 94;
violets without, 15
Stenotype, v, 313
Step-down Transformers, vi, 310
Step Faults, xiv, 116

Stephenson, George, locomotive, v, 208, 377, 378

Stephenson, Robert, link motion, v, 208-10, 379

Steppes of Russia, grasslands, xiii, 181, 373, xiv, 381;
impossibility of forests, xiii, 349;
wind-fertilized vegetation, 149
Step-up Transformers, vi, 309
Stereopticon, iv, 341-2
Stereoscope, xi, 177-81;
depth impressions by, ix, 120;
in lightning study, i, 148;
in photographic map-making, i, 45-6
Stereoscopic Wind Maps, i, 230, 231, 233
Stereotyping, v, 302-3, 383
Sterilization, by heat, viii, 371-2;
by ozone, vii, 354;
by X-rays, 257
Sterilized Milk, vitamines in, x, 262
Sterling Silver, viii, 171
Sternoptychidæ, xii, 23
Sterols, viii, 350
Stethoscope, ix, 205;
discovery and use of, x, 108-10, 112, 371
Stevens, Col. John, steamboat, v, 189

Stevenson-Huntington, on crocodiles, xii, 199-200

Stevin, Simon, xvi, 103-4, 109
Sthenic Disease, x, 89
Stichwort, in pink family, xiii, 195
Stinging Cells, xii, 33, 36
Stigma of Flowers, xiii, 46, 118, 119, 147
Stigmata, hypnotic production of, xi, 317
Stiles, Dr. Percy, on emotions, xi, 137-9;
on hypnotism, 322;
on nutrition and mentality, 369-70;
on suppression of emotions, 140-1
Stiles, Prof., on malarial parasites, x, 159
Still Engine, v, 165-70
Stills, apparatus of, viii, 250
Stimuli, Stimulations, ix, 78;
common response to varying, xi, 22-3;
law of consciousness of, 27-8;
law of summation, 21-2
Stipe, of mushrooms, xiii, 163
Stipules, xiii, 34, 35 (fig.)
Stirling, Rev. Robert, xvi, 174
Stoats, xii, 349
Stock-raising, on grasslands, xiv, 383-4
Stocks (geological), xiv, 110
Stoics, definition of thought, xi, 228;
fatalistic logic, 240;
principle of reason, 228, 233-4;
suppression of emotions, 140

Stokers, automatic, v, 211-12, vi, 354, viii, 46

Stokes, William, x, 112;
ether theory, xvi, 137
Stoma, of leaves, xiii, 78, 82, 103, 109
Stomach, action of, ix, 230-8;
action in hunger, ix, 88, 231, xi, 65-6, 123, 124;
adjustment to meals, ix, 85;
bacteria, few in, x, 201;
brain and, xi, 370;
condition between meals, ix, 230-1;
control of action of, 163;
disorders of, 238-41, x, 321-5;
emotion effects on, ix, 165, 166, 241, xi, 135, 137;
food absorption from, ix, 243-4;
form and position, 233 (fig.), x, 321;
functions in digestive process, viii, 356-7, 358, ix, 232, 234-6, x, 319-21;
functions in maintenance of life, ix, 21-3;
habit in functioning of, 251;
in infants, 346;
muscles of, ix, 74, 85, 160-1, 162;
nervous connections of, 164-5;
position in circulatory system, ix, 198;
smell effects, xi, 69;
supporting framework, ix, 71;
ulcer of, cause, x, 224;
worry effects on, ix, 165;
X-ray examination of, x, 373
Stomach Catarrh, x, 253
Stomiatidæ, xii, 23
Stone, Cheselden's operation for, x, 92;
Oath of Hippocrates on, 19
Stone Age, agriculture, xiii, 209, 210;
bow and arrow in, xv, 214;
end of in Europe, xvi, 50;
fire uses in, xv, 229;
tools of, v, 13, 14, xvi, 47

(see Eolithic, Neolithic, Paleolithic Periods)

Stone Axes, primitive, xv, 192 (fig.)
Stone Buttons, xvi, 29
Stonehenge, xv, 271-2;
solstitial orientation at, ii, 26
Stone Flies, xii, 106
Stone Lilies, iii, 268-70, 256 (Pl. 14)
Stone Meteorites, ii, 291, 292
Stone Mountain, exfoliation on, iii, 24
Stone Pestles, xv, 238
Stone Structures, ancient, xv, 269-72
Stones, art of breaking, v, 12;
breaking of, by freezing water, iv, 150-1;
cutting in ancient Egypt, xvi, 67
Stone Tools, beginning of, v, 11, 12-14;
evolution of, xv, 102-10
Stone Walls, cleaned by air jets, v, 185-6
Stoney, on planetary atmospheres, ii, 231-2

Storage Batteries, iv, 298-300, vi, 130, 144-51, vii, 375;
care in automobiles, vii, 121, 144;
charging of, vi, 331, 332, 333;
chemical action in, viii, 167-9;
in farm plants, vii, 233

Storage Battery Reserves, in power plants, vi, 382-3

Storks, xii, 254, 255
Storm Cards, i, 279, 382
Storm Signals, i, 282-3
Storms, i, 134-9;
electrification by, vii, 212-13;
height in atmosphere, i, 17;
prediction of, 239, vii, 218;
rainfall of, 110-11;
wave power in, xiv, 299-300, 303

(see also Cyclones, Hurricanes, Thunderstorms)

Storm Waters, i, 382;
in sewage systems, viii, 324
Stormy Petrels, xii, 252
Storm Weather, business effects, i, 264
Stove Blacking, graphite in, viii, 43
Strabo, geography of, xiv, 3, xvi, 98;
on Vesuvius, xiv, 313
Strata, elastic, iv, 82, 157, 158
Strain Sensations, xi, 124;
in time estimation, 195-6
Straits of Calais, tidal basin, v, 176
Strangulation, effect on blood color, ix, 261
Strata, Stratified Rocks, iii, 382-3;
ages, how determined, 17-19;
formation of, 13, 54;
land forms in, 139-40, xiv, 80-99;
oldest by planetesimal theory, iii, 163;
significance of, 12;
thickness in folded mountains, 132, xiv, 228-9;
thickness of series, iii, 17
(see also Sedimentary Rock)
Stratiography, defined, iii, 383
Stratosphere, i, 20, 382
(see also Upper Air)
Stratus Clouds, i, 98, 102-3, 103
Strawberry, fertilization, xiii, 139-40;
fruit, 59;
in rose family, 197;
origin, 227;
poisoning from, x, 212;
production of new plants, xiii, 166
Strays, wireless disturbances, i, 162-3, 382

Stream Gravels, precious stones in, iii, 327, 328

(see also Placer Deposits)
Stream-line Construction, v, 236
Stream Piracy, iii, 38-9, xiv, 177-83
Street Cars, reading on, xi, 373-4
Street Cleaners, vacuum, v, 137
Street Fakers, crowd psychology and, xi, 328
Street Lighting, vi, 278-9
Street Railways, air-propulsion in, v, 133;
electric, vii, 180-93, 197;
underground wires, 11-14
(see also Electric Traction)
Streptococci, x, 195, 221
Stress, elastic, iv, 157, 158

Streubel, Prof, Ernest J., author Electricity, Vol. vi, vii

Striated Rock, xiv, 56

Strikes, crowd psychology in, xi, 330

Stringed Instruments, development of, xv, 317-18

Strings, vibration of, iv, 216-17, 222-3
Stromboli, xiv, 314, 317, 321
Strombus Gigas, xii, 74
Strontium, affinity strength, viii, 128;
atomic weight and symbol, 383;
flame color, 301;
in calcium group, 148;
specific gravity, 384;
test for, 287, 289
Structural Topography, xiv, 94
Structure, geological, iii, 383

Struggle for Dominance, in plants, xiii, 337-8, 348-50, 354, 375

Struggle for Existence, xv, 21-2;
among plants, xiii, 11, 21-2, 27-8, 32, 38-9, 87, 365, xvi, 167;

Darwinian theory, xvi, 150-1;
emotions developed by, xi, 138;
in inanimate institutions, xv, 29;
in man, 25-6, 27;
in tropical forests, xiv, 367
Struve, astronomer, ii, 312, 313

Strychnine, action on nervous system, ix, 132-3;
an alkaloid, viii, 240
Strychnos Apple, origin, xiii, 227
Stubbornness, muscular tenseness and, xi, 372
Stuber, Dr., vi, 15
Stuffiness, cause of, i, 321
Stuffing Box Packing, v, 99
Sturgeons, xii, 151-2
Style, of flowers, xiii, 46;
in grasses, 182;
in plant reproduction, 118, 119, 134, 135, 140, 141

Styria, hail shooting, i, 341, 342

Subærial Agents, of rock destruction, xiv, 47-79

Sub-Atomic Energy, Eddington on, ii, 384

(see also Atomic Energy)

Subconscious Mind, xi, 47; in dreams, x, 364, 365, xi, 294-5, 290-300;
evasions of consciousness, 300, 305-6;
in learning, 212-13, 214;
in reasoning, 244-6;
repressed ideas in, x, 355-6, 361, xi, 350-1;
revealed in smiles, 357;
work retarded by fear, 212-13, 214
(see also Autosuggestion, Suppressions)
Submachine Gun, v, 367-8
Submarine Bells, i, 191
Submarines, iv, 105-7, v, 195-202;
Diesel engines in, 162;
gyro-compasses of, iv, 254, v, 340;
Holland and Lake, 382;
motors used, vi, 239;
photographic spotting of, in World War, i, 47
Submarine Torpedoes, v, 373-4;
gyroscopes in, 340

Submerged Object photographic discovery of, i, 47-8

Submerged Plants, fertilization, xiii, 149-52

Submerged Rocks, aerial mapping of, 47

Submergence, Coasts of, iii, 37-8, 57, xiv, 253, 255-62

Subsequent Streams, xiv, 159, 174

Subsidence of Land, coasts resulting from, iii, 37-8, 57, xiv, 253, 255-62;
during Ice Age, iii, 80;
effect on streams, xiv, 40, 163-4;
in relation to coal formation, iii, 199;
of ocean bottom, 83, 168, 206;
various instances of, 78, 79, 80-2, 133, 225
(see also Level Changes)
Substantive Variations, xvi, 155

Subsurface Conditions, exploration of, v, 262-3

Subways, Beach's pneumatic, v, 138
Subway Train Systems, vii, 197-8
Succession, association by, xi, 197

Sucking, mouth deformities from habit of, x, 314;
reflex in infants, ix, 349
Sucrose, viii, 226, 242
(see Cane Sugar)

Suction, due to atmospheric pressure, i, 25, v, 112;
work by so-called, 137
Suction Dredge, v, 257-9
Suction Pump, iv, 126, v, 112-13;
atmospheric pressure in, i, 25;
early ideas of, iv, 26-7
Sudbury, Ontario, nickel of, xiv, 238

Suess, Prof. coast classification of, xiv, 247;
on North Atlantic Ocean, 290

Suez Canal, tropical disease control at, xiv, 356

Sugar, calories in, ix, 299;
chemical structure and properties, viii, 225-7, 309-10, ix, 26;
digestion and absorption of, viii, 227, 356, ix, 230, 243, 290-4, x, 270;
fermentation of, viii, 213-14, 227, 248, 249;
fermentation in intestines, ix, 248;
food value and requirements, viii, 227, 364-5, 366, ix, 27, 289-90, 300-1, x, 256, 269, 273

(see also Carbohydrates);
history of use, viii, 227, xiii, 215;
in blood, cause of excess, x, 330;
in blood, liver action on, 329;
in blood, regulation of, ix, 290-3, x, 329, 330;
in blood, increase in excitement, 293, xi, 138;
in fruits, viii, 365;
in urine, ix, 292-4, x, 330, 343;
in various foods, ix, 300;
kinds and sources, viii, 225-7, 242-3, ix, 230, xiii, 214-16;
making and storage of, by plants, ix, 26-9, xiii, 79, 80, 81, 82, 83, 214, xiv, 65;
maltose as substitute, viii, 243;
manufacture of, iv, 170;
preserving by, viii, 372;
production, 242-3;
produced artificially, xvi, 142;
respiratory quotient with, x, 270;
"showers", i, 357;
taste sensations, xi, 71-2;
testing of, by polarized light, iv, 355-6;
vanilla from, xiii, 259

(see also Beet Sugar, Cane Sugar, Maple Sugar)

Sugar Beet, xiii, 214, 216;
extraction method, viii, 242
(see also Beet Sugar)
Sugar Cane, xiii, 214-15;
ancestral home, 221;
economic importance, 208;
in grass family, 179, 181-2;
growth and structure, 26;
a monocotyledon, 178;
stem, 183;
sugar extraction from, viii, 242;
sugar in stems of, ix, 27-8
(see also Cane Sugar)
Sugar Growing, in Hawaii, v, 291
Sugar Maple, viii, 242-3;
as forest tree, viii, 86;
as source of sugar, 214
Sugar Pine, in Pacific forests, xiv, 374
Sugar Refineries, potash residues, viii, 344
Sugar Squirrel, xii, 278
Sugar Tongs, as levers, v, 24
Suggestion, Suggestibility, xi, 303-10;
in advertising, 347;
in crowds, 324-31;
hypnotism as, 311, 313-14, 316, 317-22;
outgoing reaction, 56;
psychoanalytical uses of, x, 363-4
Sulphate Group, viii, 93;
valence of, 94
Sulphates, viii, 76;
formation of, 80, 83, 118;
metal occurrence in, 130;
test of, 285, 287, 290;
in urine, x, 343
Sulphide Ores, viii, 76, 77, 130, 198;
extraction of metals from, 131, 270-1, 271-2
Sulphite Pulp, v, 292, 293-4
Sulphites, test, viii, 290
Sulphonic Acids, viii, 236, 237
Sulphur, viii, 76-7;
axis ratio, iii, 317;
combustion of, viii, 11-12, 13, 57;
compounds, 18, 77-83;
electrification of, iv, 257, 259, vi, 12;
energy in native, viii, 268;
ignition of, viii, 53;
in body tissues, 354;
in coal, 118;
in gunpowder, 145;
in iron ore, iii, 356;
in ores, viii, 77, 131, 270-1;
in proteins, 351;
in rubber making, 257-8;
in steel, removal of, v, 320;
melting requirements, iv, 162;
occurrence in nature, iii, 339, viii, 19, 76, 118, 193, 198;
odor of, iv, 131;
plants uses of, viii, 337, ix, 29;
presence in minerals, how determined, viii, 201;
silver tarnished by, 13, 77, 171;
uses, iii, 339, viii, 77;
valences of, 94
Sulphur Dioxide, viii, 78
Sulphur Showers, i, 61, 355, 359
Sulphur Springs, viii, 77, xiv, 144
Sulphur Trioxide, viii, 78, 79, 80-2;
affinity for water, 101
Sulphuric Acid, viii, 79-83;
action on cellulose, 255;
formation in body, x, 280;
industrial importance, viii, 76, 78-91, 141, 275;
molecular weight, 92;
normal, 119;
production, 81-2, 275, viii, 198;
salts from, 83, 116;
solubility, 112;
strength, 115;
used in electric batteries, vi, 58-9, 131-4;
atomic weight and symbol, viii, 383;
production by electrolysis, 125;
production, iron pyrites used, iii, 336, viii, 167-9;
use in explosives, 80;
used in hydrogen preparation, 32-3;
use in vacuum refrigeration, v, 355
Sulphurous Acid, viii, 78, 115
Sumac, family of, xiii, 200
Sumatra, apes of, xii, 381-3;
cocoanut gathering, 378;
continental island, xiv, 274;
giant flower of, xiii, 363-4;
rhinoceros of, xii, 306;
tobacco production, xiii, 258
Sumatran Earthquake, "offsets" from, xiv, 335
Summation, Law of, xi, 21-2
Summer, efficiency in, i, 323;
historic cold, i, 359-61, 361-2;
hot or cool, how determined, xiv, 350;
hot in America, i, 323;
Indian, 361-2, 363;
land and sea winds in, xiv, 346;
regularity, i, 361-2
Summer Clothing, materials for, ix, 312
Summer-Day, temperature, i, 205, 382
Summer Forests, xiii, 368
Sun, ii, 165-73;
Anne Bradstreet on, 19;
atmosphere, i, 10, ii, 184-5, 225;
atmosphere, heat absorption by, ii, 170;
atmosphere, spectrum analysis of, iv, 362;
atmospheric displacement of, iv, 327-8;
axis direction, ii, 175;
"backstays," i, 169, 367;
center of solar system (see Heliocentric System);
chemical composition, ii, 113, 114, 128, 185, 211, viii, 302;
chromosphere, ii, 183, 184;
corona, ii, 184, 219-26 (see Corona of Sun);
comet tails and, 277, 278;
coronas (atmospheric), i, 183;
corpuscles from, in upper air, 144, 146, 158, 159, 160;
crepuscular rays, 169;
distance, early ideas, ii, 32, 83, 84;
distance, how obtained, 27-9, 91-2, 121, 129, 132, 166-7, 191, 263;
distance measured by Richer, 59;
disturbances affecting earth's magnetism, vi, 40;
disturbances in relation to aurora, i, 160, 161;

"drawing water," 169, 382;
eclipses (see Solar Eclipses);
electromagnetic waves from, vii, 260;
electrons shot off by, i, 144, 146;
erratic amplitude, ii, 25;
faculae, 176, 182;
goal and quit, 305;
"green and red flashes," i, 170-1;
habitability, ii, 252;
halos, i, 100, 103, 178, 180, 181;
heat from, iv, 181-2, 183, 194;
heat from, atmospheric effects, i, 123;
heat from, modified by volcanic dust, 58-9;
helium in, 12;
Herschel's studies, ii, 16;
Hipparchus on motions, xvi, 90;
hypothesis of origin, iii, 160, 161;
light and heat, ii, 168-71;
light deflection by, 81-2;
magnetism, 154, 156, 175, 176-9, 186;
motion toward Lyra, 122, 137, 305-6, 317;
movement eastward, 195-6;
observation methods, 172-3, 19;
parallax, 59, 92;
photosphere, 173, 184;
photosphere, studies, 127, 129;
physical constitution, 183-4, 185;
position in solar system, 50, 51, 163;
prominences, 179-83, 184, 211, 214;
Ptolemaic theory, 35;
pull on planets, 65;
radiant energy, 170, 384, vi, 269-70, ix, 114-15;
radiation, atmospheric effects, i, 324;
radiation, biological importance, 211;
radiation, measurement of, 88;
radiation, physiological effects, 324-5;
radiation, weather effects, 218-19, 242, ii, 186-8, iv, 194;
radiative equilibrium, ii, 382, 383-4;
reversing layer, 184, 211, 212;
"rising" of, xvi, 12;
rotation, ii, 54, 129, 175, iii, 159;
rotation discovery, xvi, 103;
rotation studied by spectroscope, ii, 120;
shrinking of, 170;
size and shape, 28, 162, 167;
solstices observed in ancient Egypt, 25-6;
source of energy, v, 177, viii, 267, 334, 347, 349, 350, ix, 25-6, 27, xiv, 32, 75;
source of organic life, xii, 11;

Spectrum of (see Solar Spectrum);
stars resembling, ii, 117, 118 (see Solar Stars);
stellar magnitude, 296;
studies at Mt. Wilson, 152, 154;
temperature of, iv, 194;
tides and, ii, 70, xiv, 291, 292;
variable star, ii, 171;
variations in heat, iii, 248;
weight, ii, 76, 77, 78, 167-8;
winds caused by, xiv, 347
Sunburn, vii, 249, 253, x, 254;
chemical cause, i, 324-5;
X-ray burns and, vii, 250
Sundews, xiii, 40
Sundial, limitations, v, 58
"Sun Dogs," i, 180, 181, 382
Sunflower, in daisy family, xiii, 206;
restricted area, 320
Sunk Country of Missouri, iii, 98

Sunlight, atmospheric effects on color, i, 165-6, 167-71;
colors of, 165, ix, 115;
disease and, x, 240, 291, 292;
energy utilized, v, 177-8;
heat of, iv, 181-2, 183;
intensity compared with starlight, vi, 272;
leaf protection against excess of, xiii, 105-6;
penetration of ocean by, xii, 22;
plants and, viii, 335, 336, ix, 27, x, 253, xiii, 14, 76-7, 79, 80, 81, 84-90, 114, 361-3, xiv, 65, 365-6, 367;
physiological effects, i, 324-5;
results of absence in forests, xiii, 369, 370;
spectrum of, viii, 302;
struggle of leaves for, xiii, 27-8, 38-9
(see also Place in the Sun)
Sunny Dispositions, xi, 55
Sun-Pillar, i, 376

Sunrise, atmospheric refraction of, iv, 323, 327-8;
green flash of, i, 170-1;
red and grey, 166;
succession of lights and colors, 167, 169;
temperature at, 76

Sunset, atmospheric refraction of, iv, 323, 327-8;
green flash of, i, 170-1;
red and gray, 166;
succession of light and colors at, 167-9
Sunshine Recorders, i, 86-8, 382
"Sunshine State," i, 86
Sun Spots, ii, 174-9, 184, 185;
corona and, 182, 184, 212, 220, 224;
discovered by Galileo, 54;
method of examining, 172;
periodicity, 171, 175-6, 185, 186;
photographic study, 127, 129;
prominences and, 182;
radiation in relation to, 171;
rotation of sun proved by, 120;
spectrum of, 117, 153, 155;
summer of 1816 and, i, 360;
weather effects, 16, 242, ii, 186
Sunstone, iii, 329
Sun Stroke, x, 252
Sun Valve, v, 331-2
Sun-Worship, at Stonehenge, xv, 272;
of agricultural peoples, 342;
of ancient nations, ii, 20, 23, 24, 25-6, 165

Supan, coast classification of, xiv, 247, 248, 249;
on landlocked areas, 190;
on river courses, 155;
on water circulation, 134
Supercooled Liquids, viii, 304-5
Super-Electric Zone, vi, 384
Superheated Solutions, viii, 304
Superheated Steam, v, 140
Superheaters, vi, 354
Superheating, method and use of, iv, 170-1

Superimposed Streams, iii, 137, 233-4, xiv, 170-4

Superior, Lake, xiv, area and depth of, xiv, 204

Superposition, in distance perception, xi, 183

Supersaturation, viii, 113
Superstitions, dread of, x, 364;
in ancient medicine, x, 12;
in savages and civilized races, xv, 354-5;
weather, i, 334-5

Suppressions (Emotions, Wishes), xi, 140-2, 206, 257;
getting rid of, 381-2;
laughter in relation to, 350-1, 353-4, 355-6, 357

(see also Repressions)
Suprapubic Cystotomy, x, 57
Suprarenal Capsules, xi, 273
Suprarenals, x, 347;
Addison's disease of, 113;
affections of, 352
Surf, destructive work of, xiv, 45, 47
Surface Senses, xi, 63, 64
Surface Waters, as water supplies, viii, 318
Surgery, antiseptic and aseptic, x, 146-8
(see also Antiseptic Surgery);
history of development, 13-14, 24-5, 27, 32, 35, 37, 38, 39, 41, 43, 55-8, 78-81, 90-7, 121-5, 129-31, 144-9, xvi, 63, 108, 181, 182-4, 185;
hypnosis in, xi, 316-17;
made a scientific profession, x, 104-5;
plastic, 57, 189, 384;
separation from general medicine, 16-17, 35, 38, 39, 41, 43;
three perplexities of early, 14, 123, 134, 148;

X-rays in, vii, 256
Surgical Dressings, sphagnum in, xiii, 160-1
Surinam Eel, vi, 16
Surinam Toad, xii, 175
Süring, balloon ascension, i, 18, v, 225
Surprise, effects of strong, xi, 21
Surra, disease, x, 168
Surukuku, xii, 234
Surveying, by aeroplane, i, 46-7;
history of development, xvi, 68-9, 91, 98

Survival of the Fittest, x, 136, xiii, 334-5, 346, xv, 23, 24-5, xvi, 150-1, 152;
in human race, xv, 27, 47-8;
in plants, xiii, 12, 89;
in social institutions, xv, 30
(see also Struggle for Existence)
Susceptibility, racial, xv, 50-2

Susquehanna River, cutting of present course, iii, 36, xiv, 168-9;
drowned valley of, 40, 255-6;
former extension and branches, 256;
gap of, 51, 167;
heterogeneous stream, 155;
in Glacial Epoch, 171;
superimposed character, iii, 137, 233;
transverse course, xiv, 99, 154
Susquehanna Valley, origin, iii, 232
Sutlej River, aerial mapping of, i, 46
Suttee, xv, 335

Swallowing, ear pressure equalized by, xi, 101;
effect on sphincter muscles, ix, 231;
movement of, 82;
operation, how learned, xi, 37-9;
saliva necessary to, ix, 228-9
Swallows, xii, 268;
seed dispersal by, xiii, 341
Swamp Azalet, xiii, 208 (fig.)
Swamps, coal-forming conditions in, iii, 199;
ditch-digging in, v, 216;
draining of, by trees, xiv, 379;
formed by filling lakes, 212;
of Coal Age, iii, 200, 253, 254, xiii, 309, 312;
plant formations of, xiv, 372;
shrubs suitable for, xiii, 275
Swann, Dr. W. F. G., i, 145, 146
Swans, xii, 257, 258-9;
wing power of, xv, 18
Swape, v, 18-19
Sweat, ammonia in, ix, 276;
body heat regulation by, 169, 315-16, 317;
control of, 168, 169;
in sleep, xi, 285;
odor, to what due, ix, 315;
poisons exhaled in, 269;
purpose, xi, 271, 272
(see also Perspiration, Sweat Glands)
Sweat Center, ix, 315, 316
Sweat Glands, ix, 314;
body heat regulation by, 169, 314-16;
fever effects on, 318;
nervous control of, 168, 169;
water and waste removal by, 271, 274, 276
"Sweating," of ice pitchers, i, 121
Sweat Shops, air poisons in, ix, 270;
tuberculosis and, x, 291
Sweden, coast of, xiv, 247;
crustal movements, iii, 80;
fiords of, xiv, 259;
Ice Age in, iii, 246;
nitrogen fixation, i, 36
Swedenborg, theory of universe, ii, 367
Swedish Language, xv, 162
Sweet, taste of, ix, 95, xi, 70, 71, 72

Sweet Alyssum, xiii, in mustard family, xiii, 197

Sweet Fern, xiii, 192 (fig.)
Sweet Gum Tree, petals absent in, xiii, 195;
in landscaping, 271-2
Sweet Pea, flower, xiii, 138
Sweet Potato, xiii, 218-19;
American origin, xiii, 221, xiv, 382;
root of, xiii, 13
Sweetsop, origin, xiii, 227
Sweet Woodruff, xiii, 205
Swellings, cause of, ix, 222
Swift, Dean, on moons of Mars, ii, 241
Swift River Valley, iii, 96 (Pl. 5)
Swifts (foxes), xii, 344
Swifts (lizards), xii, 203
Swim Bladder, xii, 136
Swimming, equilibrium sense in, ix, 90;
reflex processes in, 155-6
Swine, xii, 310-11
Swiss, in Alpine group, xiv, 49
Switchboards, of power plants, vi, 360, 375;
remote control by, 100-1
Switches, electroller, vii, 68;
inverse-time, 37;
oil, 41
Switzerland, cirques of, xiv, 58;
civilization of, xv, 131;
independence due to Alps, xiv, 243-4;
lakes of, 200;
ocean trade of, 306;
population and industries, 241-2;
winds, i, 133;
in World War, xiv, 244

Sycamore Tree, calyx and Corolla absent, xiii, 46;
leaf buds, 34
(see also Plane Tree)
Sydenham, Thomas, x, 72-4, 81, xvi, 108-9;
malaria in time of, 10, 155;
on "comatose fever," 301;
pupils of, 76, 77;
smallpox studies, 100
Syllogism, invention, xvi, 88
Sylvius (De la Boe), x, 69-70, xvi, 108;
Locke on, x, 75
Sylvius, Jacobus, x, 51, 52-3
Symbiosis, x, 221, xiii, 98-9
Symbols, of chemical elements, viii. 91, 383
Syme, James, x, 144
Symmetry, idea of, inborn in man, xv, 251;
in organisms, major and minor, xvi, 155

Sympathetic Nervous System, x, 352-3, x, 113, 134-5, 137

Sympathetic Vibration, iv, 225-6, vii, 118, 261-2

Sympathy, instinct of, xi, 56;
empathy and, 172;
suppression of, 141
Synæsthetic Images, xi, 222
Synapses, defined, xi, 20;
retardation at, 20, 21, 71, 154
Synchronism, defined, vii, 376

Synchronizing Action of alternators, vi, 383-4

Synchronous Charts, i, 214-15, 383
Synchronous Condensers, vi, 262
Synchronous Converters, vi, 343-8
Synchronous Motors, vi, 241, 255, 256-63;
in motor-generator sets, 332, 342
Synchronous Speed in motors, vi, 241, 247
Synchronous Vibration, vii, 118, 261-2
Synclines, iii, 85, 133, 383 (fig.);
hot springs and, 128
Synodic Period, of moon, ii, 196
Synonyms, botanical, xiii, 171
Synoptic Charts, i, 215, 383
Synthetic Races, xii, 134
Syphilis, history of, in Europe, x, 60;
Hunter's study of, 95;
mercury for, 60, 104
Syria, gazelles of, xii, 327;
Rift Valley or Ghor, xiv, 120-1
Syrinx, of birds, xii, 248, 249

Systole and Diastole, of arteries, x, 62, 63-4, 65;
heart, 65
Tabit ben Korra, ii, 38
Table-lands (see Plateaus)
Table Mountain, South Africa, xiv, 225;
cloud cap, i, 105, 383;
fog drip, x, 351
Table Mountains (mesas), xiv, 81, 82
Table Salt, impurities in, xiv, 296
Tacking (sailing), v, 182, 188
Taconic Range, iii, 188-9, 190, 192, 210;
antiquity of, xiv, 235
Tadpoles, xii, 175, 179, 181;
regeneration in, 170
Tagliacozzi, x, 57-8, 189
Tahiti, vanilla production, xiii, 260
Tahiti Apple, xiii, 227
Tahoe, Lake, iii, 153-4
Tails, rudimentary, in man, xv, 56
Talbot, Fox, xvi, 192
Talc, iii, 339-40;
chemical composition, viii, 90

Talking Machines (see Phonograph, Graphophone)

Tallow, animal fat, viii, 246

Tallow Candles, viii, 247

Talman, Prof. C. F., author Meteorology, Vol. i

Talons, xii, 260
Talus, defined, iii, 383
Talus Slopes, in arid regions, xiv, 77-8;
of mountains, 233
Tamandua, xii, 282
Tamarinds, origin, xiii, 227
Tamerlane, grandson of, ii, 39, 300
Tamia-caspi, i, 352
Tampers, pneumatic, v, 135
Tampico, harbor of, xiv, 266
Tan, skin, vii, 249, 253
Tanagers, xii, 245, 269
Tanganyika, Lake, size, xiv, 204
"Tanks", in World War, v, 218, 384
Tannic Acid, in tea, xiii, 231
Tannin, uses of, viii, 257, 259
Tanning, of hides, viii, 257;
in ancient Egypt, xvi, 73
Tantalum, symbol and atomic weight, viii, 383
Tapegrass, fertilization, xiii, 150-1
Tapeworm, x, 200, xii, 45;
food of, ix, 18;
motions of, 73
Tapioca, source, viii, 243
Tapirs, xii, 304, 306
Taproots, xiii, 16, 17, 18
Tar, constituents of, viii, 333;
production and uses, 253
Tarantella (dance), xii, 93
Tarantulas, xii, 93
Tarnishing, of metals, viii, 13, 77, 100
Tarpons, xii, 154
Tartar Astronomers, ii, 39
Tartar, on teeth, x, 315-16
Tartaric Acid, viii, 136, 222-3, 336;
asymmetric atoms of, 309-10;
Pasteur's study of, x, 137
Tasmania, aborigines, iii, 303, 304;
animals of, xii, 277-8;
continental island, xiv, 276;
leafless yew-tree, xiii, 30
Tasmanians, hair of, xv, 38;
in black race, 37
Taste (sense), ix, 94-5, 96, xi, 69-77;
in infants, ix, 350-1;
mingled associations with, xi, 64, 127;
phonisms of, 222
Taste Buds, ix, 94, 95;
related to end-buds of fishes, xii, 137

Tastes, agreeable, digestion aided by, ix, 98, 240, x, 320

Tattooing, xv, 257 (fig.), 258-9
Taughannock Falls, iii, 50
Taylor, Bertha Fanning, xiii, 4
Taylor, Fred W., v, 54-5, 383
Taylor, Dr. Griffith, i, 324

Taylor, Prof. Norman, author Botany, Vol. xiii

Tea, history and production, xiii, 227-31;
over-boiling, 231;
polyuria from drinking of, x, 344;
wakefulness from, ix, 219
Teakettles, heating of, iv, 182-3
Tea Plant, xiii, 228, 229-30;
ancestral home, 221
Teak-wood, source, xiv, 383
Tear Gases, viii, 263
Tear Glands, blood supply of, ix, 197;
control of, 162, 163
Tears, cause, xi, 23;
taste sensations and, 76
Technical Terms, glossary of, iv, 381-4
Tectonic Topography, xiv, 94
Tedium, xi, 194-5

Teeth, ancient birds with, iii, 296, 297, xii, 241-3;
care of, ix, 228, x, 313-16;
decay of, cause and results, 312-13, 314;
decay from emotional strain, xi, 142;
defective, mental impairment by, 373;
diet and, x, 265, 314-15;
diseased, fatigue from, xi, 279;
electric treatment, vii, 237;
enamel of, ix, 13;
grinding of grains by, xv, 237-8;
infections from, x, 202, 218, 222, 225-6;
killing of nerves of, ix, 187, 188;
loss of, results on jaws, 57;
malnutrition from bad, 228;
modified scales, xii, 134;
mutilations of, by savages, xv, 260;
of carnivores, xii, 332-3, 389;
of manlike apes, iii, 303;
of Neanderthal man, xv, 98 (fig.);
of rodents, xii, 286;
of Tertiary mammals, iii, 298, 300;
poisons from decaying, ix, 269-70;
pus pockets at roots of, 187, 188;
replacing of sound, x, 56;
temporary and permanent, 313-14;
ulcerated, ix, 56;
X-ray examinations, x, 373, vii, 254
Teguexins, xii, 208
Tejus Lizards, xii, 208
Telautograph, vi, 98
Teleosts, iii, 285, xii, 142, 151-66;
eggs of, 141
Teledu, stinking, xii, 348

Telegraph, Telegraph System, iv, 292-4, vii, 108-18, 376;
cells used, vi, 127, 140;
etymology of word, vii, 91;
invention, 108, vi, 24, xvi, 188;
protection against lightning, vii, 49-50;
sounders, 375;
submarine, vi, 24
Telegraph Codes, vii, 108-9
Telegraph Plant, xiii, 114
Telegraph Plateau, xiv, 288
Telegraph Poles, in desert regions, iii, 72-3
Telegraph Wires, humming of, i, 194-5

Telephone Exchange, brain compared to, xi, 15-16;
central nervous system compared to, ix, 129

Telephone, Telephone System, iv, 305-6, vii, 91-107, 376;
automatic, vi, 87, vii, 92-3, 106-7;
cells used, vi, 138, 142;
condensers in, 285, 304;
invention, v, 381, vii, 92, xvi, 188;
magneto-generators, vi, 215;
number in New York, vii, 75;
protections against lightning, 50;
receiver, electromagnet of, vi, 99;
simultaneous messages, vii, 118-19;
vacuum tubes in, 280;
vibration rates of, ix, 101;
wire used, vii, 314
Telephony, prominent names in, vi, 26
Telescopes, ii, 93-110, iv, 345-6;
comet-seekers, ii, 274;
first used by Galileo, 54;
first eclipse seen by, 210;
Galileo's, xvi, 103;
lens improvements, 125;
limitations due to atmosphere, ii, 140, 201-2;
modern, 18, 143

(see also Bruce, Hooker, Leviathan, Yerkes Telescopes);
use in astronomical photography, iv, 372-3

Telluride Ores, iii, 366

Tellurium, classification place, viii, 182, 183;
symbol and atomic weight, 383

Temperament, classes of, xi, 153-9

Temperate Forests, xiii, 366-73, xiv, 366, 370-1;
timber supply from, 382-3

Temperate Zone, civilization in, xv, 122, 123, 127, 383, xiv, 344, 357-9;
most favorable to man, xi, 51;
weather, how determined, xiv, 349-50;
winds, i, 127-8, 135, 137, xiv, 345-6, 349

Temperature, absolute, viii (see Absolute Scale);
altitude and, i, 19, 20, 208, xiv, 364-5;
barometric pressure and, iv, 122-3, 124, 125;
body (see Body);
climate classification by, i, 208;
colors in relation to, iv, 361;
critical (see Critical Temperature);
daily range, xiv, 247-8;
dependent on atmospheric constituents, i, 14-15, 16, 58-9, iii, 248;
determining factors, i, 208, xiv, 344-7;
electrical conductance affected by, iv, 301;
equalization by water, viii, 37, 38;
gas pressure and, iv, 139-42, viii, 107;
heat and, iv, 139-40, 144-5, 153-4;
high and low attained, v, 345, 348;
highest atmospheric, i, 209;
human control of, 332-3;
human efficiency and, i, 323-4;
human feelings of, 317-18, 320-1, ix, 93-4, 319-21, xi, 112-14;
humidity and, i, 76, 77, xiv, 352-4;
infant's adjustment to, ix, 352;
latitude and, xiv, 344-5;
lowest atmospheric, i, 209-10;
maximum and minimum, i, 75-6;
mean, 203-4;
measurement of (see Thermometers);
measuring of high, iv, 137-8, vi, 62-3;
metabolism affected by, ix, 37, 78-9;
musical instruments affected by, iv, 231-2;
observations and records, i, 203-5;
of deep sea, xii, 21-2;
of electric arc, iv, 312;
of electric furnace, vii, 302, xvi, 189;
of liquid air, i, 31, viii, 68;
of meteors, ii, 285, 290;
of oxyacetylene blowpipe, i, 33;
of stratosphere in different latitudes, 20;
of sun, ii, 169, iv, 194;
optimal, xi, 51;
physical state and, viii, 303-5;
plant distribution determined by, xiv, 364-71, 374-7;
plant societies in relation to, xiii, 357, 381;
range of, on earth, ii, 243-4;
range possible for life, i, 32, ii, 243-4, 245, 249, v, 348-9, x, 250-1;
rise of, to what due, iv, 144;
scientific meaning of, 139-40, 144;
seeking of favorable, xi, 51-2;
sensations of, ix, 93-4, 314, xi, 112-14;
sensible, i, 318;
sound speed and, i, 186-7, iv, 198-9;
subterranean layers of, xiv, 12-15;
susceptibility to change of, x, 240;
sun-spot effects, i, 16;
variability, i, 204-5;
variations by night and day, iv, 134, 183;
variations, effect on timepieces, v, 71-2, 73;
variations, human effects, x, 238-9;
variations and rock weathering, iii, 23-4, 72, xiv, 41, 62, 74, 75, 77-9, 233;
ventilation factor, viii, 331, 332;
volcanic dust effects, i, 58-9;
winds in relation to, 124, 126-7, 131, 293, xiv, 345-7

(see also Heat)
Temperature Charts, i, 206
Temperature Inversion, i, 375
Tempered Scale (music), 4, 208-9
Ten Commandments, xv, 368
Tender Emotion, xi, 146, 147, 149
Tendon of Achilles, ix, 76
Tendons, ix, 59, 79;
early surgery of, x, 79, 96;
sensations of, xi, 124, 125
Tendrils, xiii, 28;
movements of, 111-12;
on leaves, 38
Teneriffe, Smyth's experiment on, ii, 141;
volcanic nature, xiv, 277, 316

Tennessee, non-glacial topography of, xiv, 56;
underground streams of, 149
Tennessee River, former course, xiv, 186
Tennis, "cutting" of balls in, iv, 67, 68-9

Tennyson, in Holmes' "goodly company," x, 134;
quoted, i, 136, 183, iii, 11, xi, 33
Tension Spring, air as, v, 136-7
Tents, Indian, xv, 266
Teratoma, x, 120
Terbium, symbol and atomic weight, viii, 383
Term Hours, i, 203, 383
Terminal, of moon, ii, 28
Terminal Moraines, iii, 67;
lakes formed by, xiv, 202;
of great Ice Sheet, iii, 67-8, xiv, 59, 200, xv, 74-6

Terminal Voltages, vi, 186, 188, 189
Terminals (see Railroad Terminals)
Terminator (astronomical), ii, 194, 202
Termites, xii, 110, 125
Terns, xii, 264
Terpenes, viii, 240, 251-2
Terra Firma, iii, 76
Terraces, defined, iii, 383;
of California, 224
Terrapins, xii, 189-90
Terrestrial Refraction, i, 171, 380
Terror, exhaustion from, xi, 135-6;
expression and origin, 131-3
Tertiary Period, iii, 20, 221-36, 383;
appearance of man in, xv, 72;
development of mammals in, xii, 271-2;
divisions and species surviving, xv, 71;
plants and animal life, iii, 257, 279, 297, 298-9, 300, 301-2, 303, xii, 104, 154, 243, 283, 366;
remains of man in, v, 11
Tesla, Nicola, vi, 26
Testudinidae, xii, 188
Tetanus, negro susceptibility to, xv, 51
(see Lockjaw)
Teptonic Races, in Nordic group, xvi, 48
Texas, chalk deposits, iii, 216-18;
chapparal of, xiv, 379;
coasts of, iii, 57, xiv, 251, 262, 263;
cotton, xiii, 237;
dust whirlwinds, i, 60;
mercury production, iii, 370;
monsoons, i, 131;
oil wells, helium from, iv, 108;
peccary of, xii, 311;
stock-raising system, xiv, 383
Texas Fever, xii, 98
Textile Machinery, v, 268-83, 376-7;
induction motors in, xi, 256;
of ancient Egypt, xvi, 72-3
Textiles, chemistry of, viii, 254-8;
Egyptian, xvi, 72-3;
fireproofing of, viii;
starch in, 243
Thackeray, W. M., brain weight, xv, 39
Thales, discovery of magnetism, vi, 11;
eclipse predictions, ii, 9, 27, 209-10;
scientific teachings, xvi, 76-7, 77
Thallium, symbol and atomic weight, viii, 383
Thallophytes, iii, 250, 251, 252, 256
Thallus, of ferns, xiii, 156-7;
none in mosses, 163

Thames River, former tributary of Rhine, xv, 76;
tidal basin, v, 176;
true mouth of, xiv, 270
Theatres, color induction in, xi, 95;
use of ozone in, vii, 353-4;
wiring, 57
Thebes, Egyptian, xvi, 64, 65, 67, 70;
papyri discovered at, x, 12
Thenard, chemical work, xvi, 162
Theobromin, polyuria induced by, x, 344

Theology, Creek, Roman, medieval, xvi, 99-100, 115

Theophrastus, zoölogical work, xvi, 126
Therapy, Therapeutics, x, 379-84;
aeronautics in, i, 51;
ancient systems of, x, 12, 13, 21-2, 26, 380;
Brunonian system, 89-90;
climatological, i, 331, x, 383;
drug, 21-2, 380-1;
electricity in (see Electro-therapeutics);
hypnosis in, xi, 317;
Locke and Holmes on, x, 74-5;
modern, 380-4;
nihilism doctrine in, 113;
open-air, 240-1, 291;
Rowntree's categories of, 380;
Stahl's system, 85;
Sydenham's glossary of, 74;
X-rays in, vii, 251, 252-3, 255-6
Thermal Belts, i, 259, 383
Thermal Couples, vi, 62-3, 72;
electron theory, vi, 123-5;
power tables, vii, 383;
source of energy, vi, 129
Thermal Springs, xiv, 143-5
(see also Hot Springs)
Thermal Unit, v, 350-1
Thermionic Valve, vi, 125
Thermodynamics, iv, 384;
great laws of, 189-94
Thermo-electricity, vii, 376
Thermo-electric Powers, vii, 383
Thermograph, i, 76, 77, 383
Thermo-junction, i, 318
(see Thermal Couples)
Thermometers, i, 72-6, 383, iv, 135-8, 145;
as comfort measures, i, 318;
comparison of scales, iv, 137 (fig.), xiii, 27, 384;
development, i, 68-9;
drugstore, 266;
Galileo's, x, 71;
metallic, iv, 146-7
Thermometer Screen, i, 375, 383

Thermos Bottle, construction and use, iv, 184-5;
invention, vii, 323;
principle, i, 31, viii, 68
Thermoscope, i, 69
Thermostat, iv, 148-9, 384, vii, 87
Thermostatic Regulators, vii, 148
Thermotaxis, xi, 51-2, 61
Theromorpha, xii, 184-5;
mammals developed from, 271
Thibet (see Tibet)
Thigh, bone of, ix, 68, 70 (fig.)
Thimbleberry, xiii, 199 (fig.)
Thinking, law and process of, xi, 201
(see also Thought)
Thinness, x, 277
Third Dimension, perception of, xi, 173-83

Third Rail System, vii, 187, 189, 197-8, 199 (fig.)

Thirst, exercise effects, x, 303-4;
sensation of, ix, 87, 88-9, xi, 66-7;
sense of, in infants, ix, 350
Thomas, Holt, on airships, i, 42
Thomas of Sarzona, x, 44
"Thomas W. Lawson," schooner, v, 188-9
Thompson, Benjamin (see Rumford)
Thompson, S. P., vi, 26
Thompson, William (see Kelvin)
Thomson, Elihu, vi, 26

Thomson, J. J., cathode ray studies, xvi, 193;
electron theory of, iv, 55, vi, 26;
experiments on gas cooling, i, 30
Thomson Water Meter, v, 87

Thorax, diagnosis of diseases of, x, 98-9, 109;
of insects, xii, 99, 102
Thoreau, on Indian summer, i, 362
Thorium, in soil and air, i, 143;
radioactivity, viii, 184, 186;
symbol and atomic weight, 383
Thorn Tree of Natal, xiii, 375
Thorpe, John, ring frame, v, 378
Thothmes, war chariot of, xv, 242

Thought, brain processes in, ix, 147-53, xi, 15;
cerebrum seat of, ix, 167;
gray matter and, xv, 63;
habits of, xi, 198, 203-4, 247;
language and, xv, 143-45, 146;
law and process of, xi, 201;
need of changes of, ix, 138;
nervous mechanism, xi, 19-20;
physical essentials and costs, 25;
speed of, 13
(see also Reaction Types);
Stoic definition, 228;
stream of, 193;
similarity in laws of, xvi, 42-3
"Three Fates", painting, xi, 192
Three-Horned Beast, iii, 292
Three-phase, meaning, vi, 207
Threes, multiplies in plants, xiii, 176, 178
Threshing Machines, v, 248-9
Threshold of Sensation, xi, 71;
of distance discrimination, 184, 185;
in various senses, 80, 104-5, 111
Throat, as infection focus, x, 219, 224;
connections with ear, ix, 101, 102 (fig.);
drying of, in thirst, iv, 88;
in speech production, ix, 83
Thrombosis, x, 336
Thrush, disease, x, 196
Thrushes, xii, 269
Thrust Bearings in Niagara Plant, vi, 374-5
Thrust Faults, iii, 87, 88 (fig.);
examples, 90-2, 188, 219
Thugs, jaws of, xv, 43
Thulium, symbol and atomic weight, viii, 383
Thulis, astronomer, ii, 275
Thumb, flexibility of human, ix, 67-8;
of apes and men, xv, 58-60
Thunder, i, 383;
at sea, 193;
cause of sounds, 192-3;
distances heard, 188-9;
explanation, vii, 210-11;
general awe of, 201-2;
large raindrops and, 215-17;
reverberations of, iv, 238;
speed of sound, i, 187
Thunderclouds, i, 102, 296;
formation, 93
Thunderhead, i, 139 (fig.), vii, 217
Thunderstorms, i, 138-9, 383;
astraphobia, 330;
classes and causes, vii, 217-18;
dangers and protection, i, 155-7;
hail in, 106, 120, 373-4;
lightning flashes, 149-52;
potential differences in, vii, 352;
St. Elmo's Fire in, i, 157;
strays and, 163;
vertical currents in, 293
Thunderstorm Recorders, i, 163, 383
Thuringian Forest, xiv, 238
Thylacine, xii, 277-8
Thyme, flowers, xiii, 205;
origin, 265
Thymol, viii, 238, 333
Thyro-globulin, x, 351
Thyroid Gland, x, 347, 348;
disorders and treatment, ix, 303-4, xi, 60-1;
functions and disorders of, x, 348-52;
inflammation of, and rheumatism, 224;
operations on, 148;
secretion used as drug, 382
Tiamat, or Chaos, xvi, 77
Tian Sham, xiv, 232
Tiber River, delta of, xiv, 263

Tibet, bears of, xii, 337, 338, xiv, 205, 211;
marine deposits, iii, 235;
plateau of, xiv, 97, 222, 232;
polyandry in, xv, 286;
rainfall, i, 111, xiv, 355;
wild ass of, xii, 308;
yak of, 330
Tibetans, in yellow race, xv, 37
Tickle, Tickling, sensation of, ix, 92-3;
sense of, xi, 109, 114;
laughter from, 355
Ticks, xii, 98
Tickseed, seed dispersal, xiii, 58, 343
Tick Trefoil, xiii, 58
Tidal Estuaries, formation of, xiv, 164, 255
Tidal Friction Theory, ii, 375-7
Tidal Power, v, 174-7
Tidal Races, xiv, 294
Tidal Waves, from earthquakes, xiv, 337;
from Krakatoa eruption, iii, 101, xiv, 324
Tide-predicting Machines, v, 327
Tides, xiv, 291-5;
Bacon's lunar theory, xvi, 101;
cause, ii, 70, v, 177, xiv, 32, 291;
erosive work of, 44-5;
importance to shipping, 295;
local ranges and peculiarities, 293-4;
neap and spring, ii, 70;
daily occurrence, xiv, 291-2, xiv, 292;
power utilized, v, 174-7;
"races", 294;
variations in rise and fall, 292-3
Tides, Plastic, ii, 375
Tide Water, sewage disposal in, viii, 325
Tied Images, xi, 221

Tierra del Fuego, climate and forests of, xiv, 371

Tiger, saber tooth, in Europe, xv, 76;
strength of, 18
Tigers, xii, 357-60;
apes and, 362;
Tiger Triton, 172-3
Tigris River, civilization on, xv, 123;
mapping of flood areas, i, 47;
rafts used on, xv, 264;
union with Euphrates, xiv, 185
Tilefish, xii, 164
Till, glacial, iii, 67, xiv, 59, 61
Tillamook County, Oregon, rainfall, i, 112
Tilling Machines, v, 244
Timber, source of, xiv, 382-3
Timber Line, xiv, 233
Timber Wolf, xii, 340
Timbre, of sound, xi, 104
Timby, Theodore R., v, 380

Time, absolute and relative, ii, 80, iv, 16-18;
coordinate for determining events, 16;
geological (see Geological Ages);
measuring of, v, 57-74;
memory perception, xi, 208;
Newton on absolute and relative, iv, 15;
origin of word, xi, 192;
perceptions of, 192-6;
primary concept, iv, 14, 15;
relative, Newton on, 15;
relativity doctrine, xvi, 196-8;
units of, iv, 15-16, 45, 46, 70
Timepieces, Chaldean, xvi, 58;
civilization and, v, 57;
historical development, 58-65
Time-rate, iv, 383
Timocharis, ii, 28-9, 31
Tin, viii, 161;
alloys with lead, melting point, iv, 161-2;
atomic weight and symbol, viii, 383;
affinity strength, 128;
extraction from ores, 271;
fusibility, 384;
in heavy metal group, 126-7, 154;
melting point and requirements, iv, 162;
positiveness, vi, 59;
production and uses, iii, 368-9;
specific gravity, viii, 384;
tests for, 287, 288;
uses, viii, 161
Tin Plating, viii, 273
Tinstone, viii, 161
Tint, of colors, xi, 90
Tips, of plants, xiii, 111, 114
Tire Pumps, heat of, v, 351
Tires, iron, on wagon wheels, iv, 4, 134-5;
pneumatic and other, v, 133-4
Tissue Fluids, ix, 50;
abundance in connective tissues, 59;
constituents, 173-81, 189-90;
oxygen supply, 253, 254, 260;
renewal and supply system, 51 (fig.), 191, 193-5;
waste products removal, 221-2, 262

Tissues, amino acids in, ix, 284, x, 204, 277-8;
blood acidity neutralized by, 280, 281;
carbon dioxide, production and removal, ix, 262, 264;
chemical composition, viii, 298, 348, 354, 355;
colloidal condition, viii, 356;
connective (see Connective Tissues);
diseased, composition and X-ray treatment, vii, 253, 255-6;
electricity effects, 247;
energy sources, ix, 289, 290, 291, 297;
growth of various kinds, 47-8, 286-7;
infections of, x, 204;
"irritability" theory of, 86;
oxygen needs and supply, ix, 253, 260, 261-2, x, 331, 338;
protection against germs, 201;
protein needs, viii, 359, ix, 278-84, 287-9, x, 204, 277-8;
resistance to germs, 197-8;
spaces for fluid, ix, 50;
wastage, normal, 281-3;
wastage in starvation, 297-8;
waste removal, 271;
water in, viii, 39
(see also Body Cells, Protoplasm)
Titan, moon of Saturn, ii, 249-50
"Titanic," loss of, xi, 332
Titanium, symbol and atomic weight, viii, 383
Titchener, Prof. on imagination, xi, 225;
on skin, 114;
on reaction types, 155
Titicaca, Lake, xiv, 205
Tivoli, Italy, travertine deposits, xiv, 146;
waters of, 147
Tjemoro Tree, xiii, 15
TNT (see Trinitrotoluol)
Toads, xii, 169, 174-7;
evolution of, 167;
rains of, 177
Toadstools, xiii, 164
Toasts, origin of, xv, 363
Tobacco, xiii, 256-9;
American origin, 221;
xiv, 382;
historical importance, xiii, 208;
hyperacidity of stomach caused by, x, 322;
ripened by bacteria, 194
Tobacco Leaf, X-ray sterilization, vii, 257

Todd, Prof. David, author Astronomy Today, Vol. ii.

Toddy, flowering of, xiii, 53
Toes, bones of, ix, 69;
rising on, muscle used, 76;
of infants, xv, 61;
use of, by apes and men, 60, 61
Toilet Soap, viii, 142
Toledan Tables, ii, 38, 39
Toledo, blades of, v, 315;
conquest of, effects, x, 37
Toluene, derivatives, viii, 238-9;
from coal tar, 253
Toluidine, viii, 237
Toluol, viii, 235
Tom, Mount, iii, 212, xiv, 111
Tomahawks, xv, 208
Tomatoes, adventitious roots, xiii, 19-20;
berries, 54;
calories in, ix, 299;
food value, viii, 365, ix, 30;
origin, xiii, 221, 224, xiv, 382;
splitting of, xiii, 94
Tomato Tree, origin, xiii, 227
Tomboro, dust from eruption, i, 59, 360
Tommasi, Crudeli, x, 155
Ton, unit of weight, iv, 283-4
Tonal Fusion, xi, 106
Tones, musical, iv, 207, xi, 105-6;
number in Indian scale, xv, 314;
pitch and intervals, ix, 99-100;
qualities of, xi, 104, 105;
simple and compound, iv, 213-17;
vibration rates, iv, 204

Tongue, functions in voice production, ix, 83;
muscles of, 77, 83;
nerve connections, xi, 76;
of chameleons, xii, 209;
of serpents, 211-12;
of toads and frogs, 174;
papillæ, xi, 70, 71;
response to taste, 62;
taste buds of, ix, 94, 95;
touch organs of, 92
Tonopah District, Nevada, xiv, 126 (fig.)
Tonsilitis, rheumatism and, x, 223
Tonsils, infections of, ix, 187, 188, 224;
infections through, x, 198, 202, 219, 220, 221, 223-4, 225;
lymph nodes, ix, 224;
removal of, 224
Tool-making Animals, v, 9-19
Tools, adjustment to workmen, xi, 362;
antiquity of hand, v, 42;
early use of, iv, 24;
historical development, v, 12-16;
machine, 42-56;
of ancient Egypt, xvi, 67;
pneumatic, i, 27-8, iv, 129;
resemblance to hand, xi, 44-5;
stone, evolution of, xv, 102-10;
use by man and animals, v, 9-11, ix, 67-8
Tool Steel, v, 55
Toothache, hypnotic treatment, xi, 315
Top Shells (Trochus), xii, 71-2
Topaz, iii, 340;
oriental, 327
Topography, changes in, xiv, 29-30;
changes, how effected, 33-79;
fault and joint effects, 114-33;
forms determined by rocks, 80-113, 125-6;
importance in war, 92-3;
of old and new areas, iii, 33-5, 36-7, xiv, 30, 47-9;
winds affected by, i, 294, 296-7
(see also Land Surfaces, Relief Features)
Tops, as gyroscopes, v, 339
Tornadoes, i, 137-8, 383;
cores, 299;
devices to dispel, 335-6;
electrification by, vii, 212-13;
lifting power, i, 356;
miscalled cyclones, xiv, 349
Tornado Insurance, i, 269
Torpedo Fish, vi, 16, xii, 149-50
Torpedoes, from aeroplanes, v, 375;
submarine, 340, 373-4
Torque, defined, iv, 384;
of motors, 309, vi, 224-7, 232, 234;
in induction motors, 24 5, 247-8

Torricelli, barometer invention, i, 68, iv, 29-30, 114, 121 (fig.), xvi, 109, 177;
scientific work, 104, 109-10, 111
Torsion Balance, invention, vi, 17-18
Torsion Pendulum, v, 74
Tortoises, xii, 182, 185-94
Tortoise Shell, xii, 185-6;
commercial source, 193
Totalizers, i, 118, 383

Touch (sense), ix, 91-2, 314, xi, 109-11, 114-15;
arrival platform for, ix, 146;
development of, xi, 43;
in fishes, xii, 137;
in infants, ix, 349;
in men and apes, xv, 60;
quality differences, to what due, xi, 164-5;
space perception by, 163, 164-6, 184
Touch Blends, xi, 127-8
Touch-me-nots, xiii, 56
Toul-Verdun Line, France, xiv, 90-1
Tourmaline, iii, 340;
light polarization by, iv, 354
Tours, cave dwellings near, xv, 266
Toxins, x, 196, 197, 296, 299

Trachea (windpipe), as infection center, x, 220

Tracheata, xii, 81
Trachoma, racial susceptibility to, xv, 51
Traction, of locomotives, v, 207;
Electric (see Electric Traction)
Tractors, motor, v, 214, 215-18, 243;
of airplanes, iv, 34
Trade Marks, psychology of, xi, 348
Trade Winds, i, 127, 383, xiv, 348-9;
Columbus and the, i, 128-9;
deflection by earth's rotation, xiv, 32, 348;
dryness of, 355-6;
in Mediterranean lands, 358;
"pulse of atmosphere," i, 218;
salinity of sea affected by, xiv, 296;
variations and depth, i, 130
Traditions, crowd psychology in, xi, 333
Trailing Arbutus, xiii, 202, 351
Training, continuity of, xi, 257
Train Sickness, cause, xi, 127
Traits, hereditary, ix, 328-9
(see also Characteristics)

Trances, Hindoo belief regarding, ix, 11-12, 17, 266-7;
primitive conception of, xv, 328
Transformation of Energy, vi, 128-9;
by muscle cells, ix, 74;
by plants, 27;
in Wilberforce Spring, iv, 85
Transformers, Current, vii, 44-5
Transformers (Potential), vi, 159-60, 306-29;
distinguished from current, vii, 44-5;
distribution units, 25-6;
efficiency, vi, 317, 317-18, vii, 367;
importance of understanding, vi, 9;
in electro-therapeutics, vii, 245-6;
in power plants, vi, 364, 376-7;
in radio generation, vii, 266;
in traction systems, 199;
voltage possible, 9-10
Transfusion of Blood, x, 337-8
Transits, defined, ii, 189;
eye-and-ear observations, xi, 155-6
Translation, energy of, iv, 83-5;
motion of, 85-6
Translations, inadequacy of, xv, 146
Translucent Substances, iv, 324
Transmigration of Souls, xv, 333-4;
morality and, 356-7
Transmission Gears, hydraulic, v, 105-6
Transmitter, telephone, vii, 93-4, 96
Transmutation of Elements, viii, 188-9
Trans-Neptunian Planet, ii, 270-2
Transparency, of glass, viii, 305
Transparent Substances, iv, 324

Transpiration (plants), xiii, 103, 104, 113, 374, 378, 379, xiv, 377-8, 378-9, 379

Transportation, aerial, i, 39, 41-3, 44-5;
civilization and, v, 18;
evolution of, 17-18, xv, 13, 241-3;
friction in, v, 203, 204-6;
meteorology in, i, 267-8;
motor trucks, v, 214;
river, xiv, 191;
wheels, v;
legs, v, 214-15
Transportation Problem (U. S.), vii, 194-5
Transvaal, climate conditions, xiv, 224;
gold production, iii, 365;
law against rain-making, i, 336
Transverse Rivers, xiv, 154;
in Appalachians, 167, 168-9
Trapdoor Spiders, xii, 97
Traps, animal, xv, 224 (fig.), 225-7;
avoidance of, xv, 66
Trauma, x, 255
Travel, educational advantages, vi, 330
Traveled Soils, xiv, 69-75
Traveler's Tree, xiii, 106, 112 (illus.), 189
Travertine, iii, 325, xiv, 146
Treadmills, xv, 239-40
Tree Corals, xii, 43
Tree Frogs, xii, 176, 177-9;
voice of, 170
Tree of Heaven, xiii, 200
Tree Ferns, xiii, 65
Tree Snakes, xii, 221

Trees, ancient, iii, 252, 253-4, 254, 255, 256-7, xiii, 309-10;

Big (see Big Trees);
branching of, xiii, 85-6;
carbon dioxide used by, i, 10;
cone-bearing, xiii, 174 (see Conifers);
danger in thunderstorms, i, 155;
deciduous, xiii, 175;
distribution determined by Glacial Epoch, xiv, 375-7;
felling of, by Indians, xv, 262;
fog drip, i, 351;
hardiness of, xiv, 364;
landscaping, xiii, 269-72;
leaving in forests, xiii, 86-7;
marsh-draining by, xiv, 379;
moisture required by, 377-9;
northern limit of, xiv, 371, 374-5;
older than herbs, xiii, 319;
paper from fibers, v, 290, 292-5;
prairies and, xiii, 374, 375, 376;
rainfall and cold in relation to, 373;
rate of increase by seeding, xv, 19;
rime on, i, 121-2;
rings, xiii, 24-5, 26;
rings, climate changes seen in, i, 199-200, xiv, 362;
rise of water in, xiii, 94;
roots, 16-17, 19;
roots, power of, iii, 24;
shedding of leaves in dry seasons, xiv, 369;
species in America and Europe, 375;
strangled by vines, xiii, 21-2;
stunted, 367;
tallest, 94;
trunks, structure, 23-6;
United States, xiv, 372-4
Trembling, in fear, xi, 132, 133
Tremolite, iii, 321
Trench-digging, competitive test, xi, 363
Trench Fever, x, 202
Trenches, ocean, xiv, 286, 288, 289
Trenching Machines, v, 253, 254-5
Trentino, xiv, 244, 245
Trenton Falls Gorge, iii, 50, 243
Trenton Limestone, iii, 185-6
Trepangs, xii, 50
Trepanning, Hippocrates, methods, xvi, 96
Trephine Operations, x, 27, 79
Trevithic, Richard, v, 207-8, 212, 377
Trial Marriages, xv, 290
Triangles, center of gravity in, iv, 101
Triassic Period, iii, 20, 208-13, 383;
animal life of, 271 (fig.), 285, 291;
appearance of mammals in, xii, 271;
insects of, 104
Tribes, formation of, xv, 363;
primitive morality limited to, 374
Tribes, plant, xiii, 171
Tributary Streams and Valleys, xiv, 56-7
Triceratops, iii, 292
Trichina, cause of, xv, 49;
parasite of, x, 199, xii, 45
Trieste, Gulf of, springs along, xiv, 150
Trifid Nebula, ii, 355, 364, 365

Trigonometry, history of development, xvi, 54, 62, 92, 101

Trilobites, iii, 260, 276-8

Trinidad Head Lighthouse, storm waves at, xiv, 300

Tri-nitro-phenol, viii, 262

Trinitrotoluene, (T. N. T.) viii, 236, 237, 261-2

Trinitrotoluol, viii, 63;
potential energy in, iv, 82
Trinil Man, xv, 89;
brain of, 96
Triphenyl Methane, viii, 240
Triple Register, i, 88

Tripoli, intersection of eclipse paths in, ii, 216

Tripolite, iii, 335
Trogons, Mexican, xii, 267
Trojan War, hashish at time of, xiii, 239
Trolley Cars, uses and disadvantages, i, 41
(see Electric Cars, Electric Traction)
Trolley Systems, vii, 186-91, 197-200;
underground wires in, 11-14
Trombones, iv, 231
Trompe, air compressor, v, 89-91
Tropic Birds, xii, 253
Tropical Diseases, xiv, 356-7;
racial immunity to, xv, 48, 50, 51

Tropical Rain Forests, xiii, 357-66, xiv, 366-70;
woods and other products of, 383

Tropics, civilization in relation to, xv, 123, 124-7;
climate monotony, xiv, 357;
cyclones, i, 136;
dry and rainy seasons, xiv, 352;
frost in, 42;
glaciers in, 54;
health conditions, i, 327, x, 251, xiv, 356-7;
labor in, xv, 126;
land and sea breezes, i, 131;
man's development in, ix, 308-9;
products, remarks on, xiii, 259;
quinine use, 251;
rainfall, i, 109;
rainfall and forests in, xiv, 377;
seasonal temperature layer in, 13;
soil depths, 64;
snow line in, xv, 73;
thunderstorms, i, 151;
vegetation of, xiv, 366-70;
white race in, i, 327, xiv, 344, 356-7, xv, 49-50;
winds, i, 127, 135
Troposphere, i, 20, 383;
turbulent conditions, 293-6
Trotula, x, 36, 37
Trough (meteorology), x, 238, 384
Troughs, oceanic, xiv, 286, 288-9;
earthquakes and, 341
Trough Valleys, xiv, 117-21, 123-4
Trout, xii, 158-9;
wariness of, 139
Troy, siege of, plague at, x, 285
Trucks, Motor, v, 214;
advantages to farmers, vii, 230-1
Trumpet Creeper, xiii, 20
Trumpets, sounding of, iv, 231
Trunk (body), muscles of, ix, 77;
skeleton of, 64-7, 63 (fig.)

Trunk-bearing Animals, evolution, iii, 300, xii, 302

Trunks, tree, structure, xiii, 23-6

Truth, experience as test of, (Sylvius), x, 69;
men's notion of, xi, 243;
scientist's search, vi, 107
Trypanosomiasis, x, 167-79
Trypsin, x, 326
Tryptophane, viii, 351
Tsetse Flies, x, 168-70, xiv, 197, 223
Tuatera, xii, 183-4
Tubercle Bacillus, discovery of, x, 149;
killed by sunshine, 292;
tissue-killing power, 293
Tubercles (lesions), x, 293;
of plants, xiii, 98
Tubercular Lesions, x, 293;
radiation treatment of, 384
Tuberculin, x, 150, 216
Tuberculin Test, x, 372
Tuberculosis, x, 289-94;
campaign against, 171, 172, 175-6, (France), 290-2;
climatic treatment, i, 331;
contraction of, from consumptives, i, 326, x, 293;
darkness and, 253, 290, 291;
diagnosis, 216-17, 372;
discovery of bacillus of, 149, xvi, 184;
diseases leading to, x, 292;
Galen's studies of, 30;
germ of, 195, 292;
immunity to, 207;
in warm and cold-blooded animals, 206;
Koch's studies of, 149-50, xvi, 184;
local infections, x, 293;
lowered blood pressure in, 336;
outdoor treatment, 240-1, 291;
pain of, xi, 118;
portal of entry of germ, 198;
predisposition inherited, 235;
racial susceptibility to, xv, 49, 50, 51;
spinal, x, 92
Tubers, xiii, 23, 24 (fig.), 218
Tuileries, invasion (1848), xi, 331
Tulips, in lily family, xiii, 184
Tulip Tree, xiii, 271-2, 318
Tumbleweeds, seed dispersal, xiii, 345
Tumors, radiation treatment of, x, 383
Tundra Vegetation, xiii, 381
Tungsten, in steel alloys, xiv, 238;
symbol and atomic weight, viii, 383
Tungsten Lamps, vi, 267, 268;
candle power, iv, 352;
due to Acheson, vii, 300
Tunicates, xii, 19-20, 129
Tuning Forks, record of, iv, 214-15 (fig.);
reenforcement and interferences of sounds, 219, 220-1;
resonance columns and, 227-8;
sound production by, 197;
synchronous vibration, vii, 118;
vibrations of, iv, 224
Tunneling Machines, iv, 122-4, 260-1
Tunnels, compressed air use in, iv, 129;
heat encountered in building, iii, 121, xiv, 13-14;
hot water encountered, xiv, 144;
sounds of trains in, iv, 236
Tuns (shells), xii, 73-4
Tupaias, xii, 367
Turbans (shellfish), xii, 71-2
Turbinates, of nose, x, 341
Turbines (see Steam Turbines, Water Turbines)
Turf, xiii, 183
Turf Grasses, xiii, 181
Turgenev, Ivan, brain weight, xv, 39
Turgor of Leaves, xiii, 102, 103, 114
Turin, position toward Alps passes, xiv, 240
Turkestan, wild horses of, xii, 307
Turkey, coverings of women in, xv, 254;
opium in, viii, 253;
tobacco production, 258
Turkey Buzzards, xii, 260
Turkeys, xii, 261

Turkish Empire, extent of conquests, xiv, 308-9

Turks, invasion of, through Danube Valley, xv, 138;
migration and conquests of, xiv, 308-9, 311
Turner, astronomer, ii, 301, 343;
on Halley, 86
Turning Effort (see Torque)
Turnip, family and origin, xiii, 197, 224;
swelled root, 19;
vitamines in, x, 262, 266, 268
Turpentine, chemistry of, viii, 51, 240;
in medicine, Galen's use of, x, 30;
specific gravity of, iv, 109-10
Turquois, iii, 340-1
Turret Lathes, v, 52-3
Turtles, xii, 182, 185-94;
absence of fear, xi, 136;
egg-teeth of, xii, 205;
heart of, ix, 84;
Mesozoic, iii, 295;
regeneration in, xii, 170;
shell of, xv, 18;
under-shield of, xii, 184
Tuscarora Deep, xiv, 341
Tusks, evolution, iii, 300, xii, 302;
of walruses, 335
Tusk Shells, xii, 58, 74
Twentieth Century Science, xvi, 195-8
Twilight, i, 167, 384;
duration, 18
Twine Binders, v, 247-8, 381
Twinleaf, distribution, xiii, 351

Twins, identical and nonidentical, ix, 44, 327, xv, 27

Twisters, Texas, i, 60, 384
Two-phase, defined, vi, 203-4, 242
Tycho Brahe, ii, 14, 45-8, iv, 95, xvi, 102;
as astrologer, ii, 21;
eclipse of 1560 and, 210;
new star seen by, 12, 331;
Kepler and, 49, 50;
star catalogue of, 300-1
Tylor, Prof. E. B., "Anthropology" of, xv, 4;
on English spelling, 177
Tyndall, fog signal studies, i, 189, 190
Tyndall Effect, viii, 315
Type, invention, v, 300;
movable, Chinese, xv, 179
Typesetting Machines, v, 307-12

Typewriters, development, v, 312-13, 380, 381;
to take spoken words, 331;
used in telegraphy, vii, 112-13
Typhoid Fever, x, 286-88;
consumption from, 292;
death rate, viii, 321-2, x, 286, 288;
discovery of germ, xvi, 185;
feeding in, ix, 319;
from water pollution, xiv, 140;
germ, x, 194, 287-8;
germs destroyed by chlorine, viii, 86;
germ diagnosis, x, 215, 216;
immunity to, 205, 207;
inoculation against, 208, 217;
named by P. C. A. Louis, 108;
portal of entry of, 198;
prevention of, 171, xv, 49;
water pollution and, viii, 318-19, 321-2;
wells and, iii, 121
Typhoons, i, 136, 384;
locating of, 279-80;
signals (China), 283
Tyrannosaurs, iii, 290
Tyrian Dye, xii, 72
Tyrol, hail crosses, i, 341;
lakes of, xiv, 200
Tyrrhenian Basin, xiv, 291
U-boats, motors used, vi, 239
Uganda, sleeping sickness in, xiv, 223
Uinta Mts., xiv, 83, 98, 226-7, 229;
fault scarp of, 230;
little metamorphism in, 234;
no igneous intrusions in, 228, 230;
river canyons of, 83, 166
Ulcerated Teeth, electric treatment, vii, 237

Ulloa, Admiral, astronomical studies, ii, 179, 221

Ulloca's Rings, i, 184, 384
Ultramicroscopic Organisms, x, 200
Ultraviolet Rays, iv, 358 (fig.);
absorption in upper air, i, 16;
actinic effects, iv, 365-6, vii, 250;
effects on barium, 254;
frequency of vibration, 260;
in therapeutics, 253;
fluorescence from, iv, 379;
luminosity of objects in, 378;
ozone produced by, i, 16;
radiant energy of, iv, 366;
transmitted by æther, vi, 119, 269;
use of, in medicine, iv, 51;
wave lengths of, 365, 366
Ulugh Begh, ii, 39, 300
Umbel, flower form, xiii, 50, 200
Umbra, of shadows, iv, 332
Umbrella Type Generators, vi, 362
Unclean Diseases, Jewish laws on, x, 15

Uncleanliness, air poisoning by, ix, 270, 352;
diseases from, x, 290, 311;
plagues due to, xv, 49
Uncompahgre River, iv, 172, 173

Unconformities (geology) defined, iii, 171, 383;
oldest known, 175;
what they represent, 176
Unconscious Actions, xi, 27;
from habit, 254-5
Unconscious Mind, xi, 47;
in reasoning, 245-6
(see also Subconscious Mind)

Unconsciousness, from excessive breathing, ix, 266-7

Undamped Waves, vii, 273, 289-90, 291
Underclothing, proper materials, x, 307, 308;
soiled, injuriousness of, 310
Underfeeding, results, xi, 370
Underground Streams, iii, 116, xiv, 149-50;
springs and, iii, 117
Underground Transmission, vii, 11-14, 24-31;
in telephone systems, 104, 105
Underground Trolley System, vii, 187, 189
(see also Third Rail)
Underground Water (see Ground Water)
Undermining, of rocks, xiv, 131
Undernutrition, due to under-chewing, ix, 228
Undershot Wheels, v, 76

Underwriters, National Board of Fire, vii, 53-4

Underwriters' Code, vii, 54, 57, 58, 61, 62
Unfit, Survival of, xv, 27
Unger, xvi, 166, 167
Ungulata, xii, 300-31

Unicellular Plants and Animals, xii, 10, xii, 166, 167;
composition and life, ix, 48-9;
food needs of, 33;
food procuring by, 12-15, 19;
motions of, 73, 74;
perception of light and shade by, 105
(see also Protozoa)
Unicorn Plant, fruit, xiii, 57 (fig.);
seed dispersal, 343

Union Pacific Railway, Rocky Mountain pass of, xiv, 76

Unions, chemical, viii, 20-1

United States, aerial mail service, i, 44;
animals (carnivorous), xii, 337, 340, 342, 349, 350, 363, 365;

Atlantic coast, xiv, 25, 45, 246-7, 249-50,
(see also Atlantic Coastal Plain);
Atlantic coast rivers, 167;
automobile industry, v, 213-14;
bats of, xii, 371;
beet sugar production, xiii, 216;
birds of, xii, 254-69;
bison of, 329;
brontides, i, 196;
bubonic plague measures, x, 164;
buildings overheated, i, 323;
building stones, iii, 371-2;
coal and coal beds, 343, 345-8;
coal supply, v, 172;
coffee consumption, xiii, 232;
corn crops, critical period, i, 248;
cotton production, early, v, 270;
crop forecasts, i, 251;
dark days, 56-7;
deer species in, xii, 317-18, 322;
deserts of, xiv, 380;
dust deposits, i, 54-5;
dust in west, xiii, 344;
English sparrow in, xv, 21;
fire losses in rural districts, vii, 231;
first locomotive, v, 378, 378-9;
fish of, xii, 151-64;
flies of, 120;
food and vitamine question, x, 267-8;
forests, xiii, 366-73, xiv, 239, 372-4;
forests, national, xiii, 371-2, xiv, 239;
forest fires, i, 48-9, 56-7;
fresh-water mussels of, xii, 65-6;
frogs of, 180, 181;
geological works on, xiv, 171;
glacial topography in northeast, 60-2, 170-1;
gypsum production, iii, 376;
hailstorm insurance, i, 344-5;
high temperature record, i, 209;
history in relation to physiography, xiv, 61-2, 191-5, 242-3, 249-50, xv, 136;

Indian summers, i, 361;
influenza pandemics, x, 294-5;
iron and steel industries, xvi, 175;
jute production, xiii, 243;
land leveling rate, iii, 31-2;
land policy, xiv, 384;
lava plateau of northwest, 104, 164, 170, 172, 188 (see Columbia Plateau);
lengthened life in, x, 291;
lightning losses, i, 156;
lizards of, xii, 207, 208;
loess deposits, xiv, 72;
medical practice, history of, x, 104, 115-16, 121-5, xvi, 185-6;
medical schools, xvi, 181;
metal products, iii, 356-70;
meteorological organization, i, 212-13, 215-17, 221, 222;
mineral springs, xiv, 143-4, 145;
newts of, xii, 172;
opossums of, 275;
ore deposits, monographs on, xvi, 173;
oyster industry, xii, 61, 62;
Pacific coast (see Pacific Coast);
paper-making, v, 292;
pellagra in, x, 265, 268;
petroleum and natural gas, iii, 349-51, 353, 354, 355, v, 172-3;
phenological observations, i, 254-5;
plains, coastal and interior, xiv, 213-15;
potash sources, viii, 279;
power plants, viii, 74-5;
prairies, xiii, 373, 374, xiv, 380, 383;
public health fellowships, x, 172;
rainfall i, 110, 110-11, 112, xiv, 352, 360, iii, 113;
rodents of, xii, 288, 290, 293-6;
salt deposits, iii, 374-5;
scurvy in, x, 266;
seasonal advance rate, i, 256;
smoke costs, 64;
snails of, xii, 71;
snakes of, 218-25, 232-8;
snowfall, heaviest, i, 118-19;
specialization of different parts, xv, 131-2, 203;
standard units used in, iv, 45-6, 69;
summer of 1816, i, 359-61;
tea consumption, xiii, 231;
telegraph system, vii, 107-8;
thermometer scale used in, iv, 136;
thunderstorms, vii, 218;
toads of, xii, 176;
tobacco production, xiii, 256, 257, 258, 259;
transportation problem, vii, 194-5;
tuberculosis in, x, 290, xv, 49;
turtles of, xii, 189, 190, 191;
typhoid fever, viii, 322, x, 286;
volcano, only active, iii, 103;
water consumption, viii, 324-5;
water filtering in, 319, 320;
water power, v, 83-4;
water supply by wells, iii, 118;
weather prophets, i, 243;
weeds, xiii, 353-4;
western plateaus, xiv, 220;
western rivers and lakes, 188;
wheat cultivation, xiii, 211;
windmills, i, 37-8;
winds, 128, 133-4;

World War chemical and medical services, x, 176-83, 186, 187-8;

World War disabled, care of, 189-91;
yellow fever extermination, 162

U. S. Army, chemical warfare service, x, 187-8;
medical corps in World War, 177-83, 186, 187;
yellow fever campaign, 159, 160-2
United States Bureau of Fisheries, xii, 155

U. S. Bureau of Standards, aeronautical research, i, 51;
lightning statistics, 156-7
United States Forest Service, xiii, 371-2;
aeroplanes in, i, 48-9
U. S. Hydrographic Office, i, 273, 277

United States Navy, cold-air machines, v, 353;
electricity on ships, vii, 326-35;
meteorological unit, i, 311;
ocean surveys of, xiv, 283;
radio control of ships, vii, 284
U. S. Public Health Service, x, 162, 164, 175
U. S. Signal Service, i, 282-3;
meteorological observations, 216, 220

U. S. Weather Bureau, agricultural service, i, 252, 256-7;
bulletin on temperature and foods, 268;
cloud pictures, 103;
code, 234;
establishment, 216;
fog classification, 95;
forecasts of various kinds, 239-40, 242;
frost predictions, 260;
functions, 7-8;
kiosks, 267;
library, 268-9;
marine division, 273, 275-6, 281;
organization, 222;
question answering, 359;
snow surveys, 118;
Spanish war services, 309;
storm predictions, vii, 218;
sunshine recorder, i, 86-7;
term hours, 203;
terms used, 107, 108, 136;
thermometers, 74, 75;
tide predicting machines, v, 327;
triple registers, i, 87-8;
vanes used, 82;
weather maps, 228, 230, 232-7;
wind-aloft maps, 230, 231, 233;
wireless reports, 280
Units, iv, 384;
absolute and gravitational, 64-5;
atmospheric pressure, 121, 123;
electrical, 261, 284-5;
heat, 154;
magnetic force, 249;
power, 80;
work and energy, 79-80
(see also Weights and Measures)
Universal Ether (see Æther)
Universal Soul, or pneuma, x, 27, 29

Universe, electricity the basis, vi, 107-8, 113, 118;
elements, 108-9;
energy of, unchanging, iv, 40;
evolution, ii, 366-84;
geocentric conception, ii, 9-10, 34-5;

Greek theories, xvi, 76-7, 77-9, 80, 81-2, 84, 186;
magnetism pervading, vi, 40;
primary concepts, iv, 14-15;
shape of visible, ii, 352-3;
stellar, 294-9;
total available heat of, iv, 193

Universities, founding of European, x, 38, xvi, 100;
revival of learning through, ii, 11-12

University of Pennsylvania, park in grounds, xi, 188

Unknown, uneasiness in face of, xi, 224, 225
Unsaturated, defined, viii, 382
Unsaturated Paraffins, viii, 230-2
Upper Air, composition, i, 10-11, 16;
exploration, 18-19, 20-3;
rarity, 17;
sun corpuscles in, 144, 146, 158, 159, 160;
temperatures, 19, 20
(see also Stratosphere)
Ural Mountains, antiquity of, xiv, 96
Uraniborg Observatory, ii, 45, xvi, 102
Uranium, atomic number, viii, 183, 309;
radioactivity, 184, 185, 186;
symbol and atomic weight, 383
Uranus, atmosphere, ii, 250;
comet families, 271;
discovery, 15, 104, 254, 255, 267, 272;
habitability, 250;
Neptune and, 268-9, 270;
orbital deviations, 67, 79, 271;
photographic study, 183;
rotation period, 377;
satellites, 105, 268;
size and orbit, 162-3;
weight, 76, 77
Ure, chemist, xvi, 163

Urea, artificial production, xvi, 142, x, 279, 329;
composition and amount, 342;
composition and functions, viii, 230, 353-4;
in amine group, 215;
production and disposal of, x, 279, 329, ix, 284, 285

Uremia, x, 346
Ureter, ix, 273
Uric Acid, viii, 230, 354, x, 342-3
Urinalysis, x, 378
Urinary Tract, as Infection center, x, 220
Urine, acidity and alkalinity of, x, 281;
albumen in, 378;
amount and excretion, 379;
amount, on what dependent, ix, 274-5;
constituents and disorders of, x, 342-6;
Corbeil's work on, 37;
formation stages, ix, 273;
nitrogen in, 282;
salt in, 273;
sugar in, 291, 292-4;
urea in, 284;
waste products in, x, 270
Urochords, xii, 129
Urodela, xii, 169, 170-3
Ursa Major, changes in, ii, 306;
spiral nebulæ, 363-4;
system, 122, 343, 344
Utah, arid topography of, xiv, 42;
bad lands, 82;
cliff topography, 88;
mining products, iii, 360, 361-2, 362, 363, 368;
plateaus, xiv, 220, 222;
subsidence, iii, 152;
Uinta Mountains, xiv, 83;
volcanic fields of, 317, 318

Uteroplacental Circulation, discovery of, x, 94

Vaccination, discovery, x, 100-3, 207-8, xvi, 127;
present extent, x, 103;
success of, 217, 288
Vaccines, autogenous, x, 218;
in focal infection diseases, 226
Vaccinia, x, 100
Vacuum Balloons, v, 222-3
Vacuum Cleaner, iv, 127, v, 137, vii, 83-4;
atmospheric pressure in, i, 25;
for barn uses, vii, 228
Vacuum Machine, iv, 127
Vacuum Refrigerating Machines, v, 354-6
Vacuums, boiling point of water in, v, 354;
detonation from filling, vii, 211;
early attempts to obtain, iv, 29-30;
electrical nonconductors, 259;
electric discharges in, 317-18;
falling bodies in, 97;
Gessler's and Crookes's x, 183-4;
heat, v, 345-58;
high, iv, 127, vii, 376;
nature's abhorrence of, iv, 27, 114;
of steam condensers, vi, 355;
Pascal's studies, xvi, 110;
sound in, i, 186, iv, 195
Vacuum Tube Generators, vii, 274, 276-8, 291
Vacuum Tube Receivers, vii, 270, 278-80
Vacuum Tube Rectifiers, vi, 339-41
Vacuum Tube Repeaters, vi, 125
Vacuum Tubes, cathode rays in, iv, 317;
Gessler's, x, 183-4;
use in wireless service, vi, 125, 339-41, vii, 277-80

(see also Crookes Tube, Coolidge Tube)
Vagus Nerve, xi, 30
Vail, Theodore N., vi, 87
Valence (chemistry), viii, 93-4, 382;
in periodic classification, 178, 180-1, 179-80;
ionization and, 122;
table of, vii, 384;
variable, viii, 94, 179, 189;
variable in catalyzers, 102;
zero, 178, 181
Valeric Acid, viii, 220
Valley Breezes, i, 131, 132, 377
Valley Glaciers, iii, 60, 62-3, 67
Valleys, air currents, i, 294 (fig.), 296;
drowned (see Drowned Valleys);
fault-made, xiv, 117-21, 127-8;
glacial, iii, 64, 66, xiv, 56-8, 259-60;
hanging, iii, 65, xiv, 57;
historical importance of, xv, 138-9;
longitudinal in folded strata, xiv, 93, 94-6, 98, 226, 229;
people of, xv, 122;
rift or trough, xiv, 117-21, 123;
river (see River Valleys)
Valley Trains, iii, 68
Valliere River, tributary changes, xiv, 184
Valparaiso, harbor of, xiv, 265
Valve Gears, inventions, v, 379
Valves, of heart, ix, 204;
leaking, 206-7
Valvular Heart Disease, x, 332
Vampires, xii, 369, 371-2
Vanadium, use and occurrence, xiv, 238;
symbol and atomic weight, viii, 383
Van Deventer, obstetrician, x, 80
Van Drebel, Cornelius, v, 196
Vanes, wind, i, 82, 384
Vanessas, xii, 117

Van Helmont, Jean Baptiste, x, 67-9, 71, xvi, 108, 110, 111, 119, 163;
recipe for creation of mice, x, 139
Van Hise, geological work, xvi, 172-3, 174
Vanilla, xiii, 259-60;
chemical composition, viii, 239, 251
Vanity, clothes due to, xv, 253, 255;
impulse of, 185
Van Maanan, astronomer, ii, 153, 314, 363
Van Swieten, x, 77, 104
Van't Hoff, xvi, 164
Vapor Baths, temperature of, x, 251
Vapor Pressure, iv, 167-8, viii, 303-5
Vaporization, latent heat of, iv, 173-4
Vapors, condensation of, viii, 304
Variable Stars, ii, 324-30;
collision theory, 327, 329, 333;
color, 296;
discoveries by Bailey, 146;
in star clusters, 337, 338;
inception of study, 16;
sun, 171, 187
Variability, in living things, xiii, 326-7
(see Variation);
meteorological, i, 384

Variation (biological), xiii, 326-36, xv, 22-3, xvi, 151;
causes and perpetuation, ix, 327, 328-9, xvi, 153;
in human beings, xv, 27;
in plants, xiii, 326-36;
meristic and substantive, xvi, 155;
new species developed from, xv, 24-5;
principles understood in Egypt, xvi, 72;
selection and perpetuation, xvi, 154-5

Varieties, crossing of, results, ix, 333-4, x, 231, xiii, 332-3;
defined, 329-30;
mixture, 147;
origin, 326-35
Variola (smallpox), x, 100
Varney, B. M., i, 296
Varnishes, ancient knowledge of, viii, 269;
chemistry of, 264-6;
drying oils in, 245, 247
Varro, on weather vanes, i, 68
Varus, defeat of, i, 307

Vascular Cryptograms, alternation of generations, xvi, 166

Vascular System, xiii, 65-6;
not in mosses, 69;
first appearance, 303, 304, 306
Vasoconstrictor Center, ix, 215-19
Vasodilator Center, ix, 219-21
Vasomotor Center, ix, 215

Vasomotor System, efficiency, how developed, x, 238-9, 240, 241;
heat loss, regulation by, ix, 311
Vassenius, astronomer, ii, 179
"Vaterland," steamship, v, 193
Vaughn, on anaphylaxis, x, 214
Vedas, song to day-god, ii, 23-4;
weather proverbs in, i, 67
Veery, xii, 269
Vega, Arabic name, ii, 39, 302;
color, 297;
Sirian star, 115;
spectrum, 116
Vegetable Acids, viii, 222-3
Vegetable Fats, viii, 244, 246;
vitamines absent in, 369, ix, 33, x, 259, 260-1, 262

Vegetable Kingdom, chemistry of, viii, 191;
food source of man, ix, 24;
how distinguished, xii, 14-15, xiii, 13-14;
relation to animals, viii, 334
(see also Plants)

Vegetable Oils, composition and energy value, ix, 28

Vegetables, calory loss in preparing, ix, 299;
cooking of, effects, viii, 368;
food value, 365, ix, 34, 280, 300, x, 259, 260, 262, 266, 273, 279;
freezing prevention, iv, 161;
frost danger point, i, 258;
green bile from eating of, ix, 275;
origin of common, xiii, 221-4, xiv, 382
Vegetable Sheep Plant, xiii, 379
Vegetable Silk, viii, 255-6
Vegetarianism, protein supplies in, ix, 280;
remarks on, 285
Vegetation, defined, xiv, 363;
determined by climate, and soil, 363-81;
effect of light and darkness on, xiii, 84-90;
effect on winds, i, 292-3;
electrical stimulation, vii, 351-3;
growth in tropical forests, xiii, 358-9, 360, 364-5;
optimal temperature, xi, 51;
past and present, xiii, 174, 175;
phosphorescence of decaying, i, 346;
soil and rock protection by, xiv, 42;
types on what dependent, xiii, 12
Vegetative Nervous System, x, 352-3
Vehicles, evolution of, v, 17
Veins, of body, ix, 191, 195, 197-8;
of body, bleeding from, x, 39;
blood in, carbon dioxide content, ix, 263, 264;
blood in, color of, 260-1;
functions in circulation of blood, x, 63-65, 334;
connections with arteries, ix, 192-3 (fig.) 197;
valves of, 222;
of leaves, xiii, 32-3, 37 (fig.), 79
Veins, Mineral, defined, iii, 383-4;
how formed, 126
Velocity, iv, 56-7, 384;
acceleration of, 57 (see Acceleration);
energy from, 78;
momentum and, 62-3;
Newton's laws and high, ii, 80, 81;
of falling bodies, iv, 65;
relation to power in machines, 92;
required on centrifugal railroads, 74;
unity of, 64
Velpeau, x, 130
Vena Cava, ix, 197-8, 201 (fig.), x, 334;
waste fluids emptied into, ix, 222
Vena Contracta, v, 89-90

Venereal Diseases, contagion demonstrated by Saliceto, x, 39;
quacks and, 76

Venice, commercial growth and decline, xiv, 308

Venomous Snakes, xii, 224-38

Ventilation, i, 321-2, viii, 331-2, ix, 267-70, x, 237-8;
air moving systems, i, 323;
electrical, on battleships, vii, 330-1;
katathermometer in, i, 320;
importance of, to infants, ix, 352;
ozone, vii, 353-4;
perception of need of, ix, 97
Ventral Segments, of vibrations, iv, 217
Ventricles, of brain, xi, 29

Ventricles, of heart, 201 (fig.), ix, 203, 204-5

Venus (planet), ii, 190-2;
atmosphere, 130-1, 191, 192, 246;
life on, 246-7;
lucid planet, 264;
non-rotation theory, 377;
orbit, 50, 162, 163;
phases of, xvi, 103;
phases, discovery of, ii, 54, 83, 94;
size, 162, 163;
stellar magnitude, 296;
transits, 58, 129;
weight, 76, 77
Venus's Flower Basket, xii, 31
Venus's Flytrap, xiii, 40-1, 64 (illus.)
Vera Cruz, harbor of, xiv, 266
Verbal Images, xi, 222
Verdant Zones, i, 259, 384
Verdun, defense of, xiv, 90-1
Verkhoyansk, Siberia, i, 209-10
Vermilion, viii, 170
Vermont, marble production, iii, 189, 371;
summer of 1816, i, 360
Verne, Jules, novel by, i, 170
Verrazano, voyage of, xiv, 310
Vertebrae, of spine, ix, 64, 65 (fig.);
origin from coelom, xii, 87
Vertebrates, xii, 127-9;
characteristics of, 132;
classification, iii, 260;
evolution, 287 (chart), xii, 167;
geological history, iii, 281-306;
reproduction in, xv, 54;
resemblances among, 55-6;
structure and organs of, 55-6
Vertical Distances, xi, 185
Verworn, Dr. Max, quoted, xi, 67
Vesalius, Andreas, x, 46, 50-3, 65
Vesico-vaginal Fistula, x, 122
Vesta (planet), ii, 255, 257
Vestal Virgins, cult of, viii, 89;
fire of, xv, 234
Vestibule, of head, ix, 90
Vesuvius, Mount, cone of, xiv, 100, 225;
eruptions of, iii, 99-100, xiv, 313, 326, 338;
flashing arcs, i, 194;
material ejected, xiv, 326-7;
only active European volcano, 316;
soils and vegetation, viii, 339;
soils on, xiv, 329
Vetches, in pea family, xiii, 198;
leaves, 113;
used in soil enrichment, 98
Veterans of World War, care of, x, 189-91
Vibration, Vibrating Bodies, iv, 86-8, 196;
amplitude of, 211;
elasticity and, 156;
frequency defined, 205, 382;
interferences of, 218-22;
of elastic bodies, ix, 98-9, 100-1;
of rods, iv, 213-15, 223-4;
of strings, 216-17, 223;
period of, 196, 205, 383;
rate of, on what dependent, 213, 223;
sound production by, 195-6;
sympathetic, 225-6, vii, 118, 261-2;
transverse and longitudinal, iv, 215
(see also Waves)
Vibrators, electric, vii, 87
Vibgyor, i, 165
Vichy Springs, xiv, 145
Vickers-Vimy Bomber, v, 233
Vicksburg, capture of, xiv, 194
Victoria Falls, iii, 49, xiv, 131-2;
forests at, 369-70
Victoria Nyanza, xiv, 120, 204
Vicuñas, xii, 313
Vienna, siege of, xiv, 308-9
Vienna Meteorological Congress, i, 219, 220
Vigo, Juan del, x, 155
Vikings, history of, xiv, 261
Vilmorin, work on sugar beet, xiii, 216
Vincent, George E., x, 175
Vinci, Leonardo da (see Leonardo da Vinci)

Vinegar, acetic acid in, vi, 111, viii, 220, 293;
from cider, 219;
in preserving, 372;
production of, 248, 249
Vines, nature and methods, xiii, 27-8;
tendrils, 111-12;
of tropical forests, 361-2
Vineyards, and hailstorms, i, 343
Vinland, xiv, 261
Violence, and will, xi, 264

Violet (color), complementary color of, iv, 367;
primary color, 366;
vibration rate, ix, 115;
wave lengths, i, 165, iv, 360
Violet Light, fluorescence from, iv, 379;
of mercury arc lamp, 282, 283;
use of, in medicine, 51
Violet Ray Machine, x, 183-4
Violets, dogtooth, xiii, 184;
fertilization, 120;
seed dispersal, 56, 339;
stemless, 15
Violin, intervals on, iv, 208;
resonance chamber, 223
Violin-Piano, vi, 97
Vipers, xii, 229-32;
ancestry of, 225;
hedgehogs and, 367
Virchow, x, 128-9;
"Cellular Pathology," xvi, 182;
founder of cellular pathology, x, 119;
malaria studies, 156-7
Vireos, xii, 268
Virginia, former volcanoes of, xiv, 318;
mineral springs of, 143;
rainfall, i, 338
Virginia Creeper, xiii, 28

Virility, from cross breeding, xiii, 120, 122-3

Viruses, attenuating principle, x, 141, 142, 143;
filterable, 141, 161
Viscachas, xii, 289;
acquisitiveness of, 292-3;
prey of boas, 215
Viscera, emotion effects, xi, 134-5;
insensible to pain, 118
Visceral Senses, xi, 63-4
Vishnu's Temple, Grand Canyon, xiv, 84
Visibility, i, 384; in aviation, 303;
scale, 314
Vision, (sense) xi, 83-97;
compared with hearing, 98;
defects of, ix, 112-14;
distance of distinct, iv, 342, 343;
limits (wave lengths), 360, 361;
motions connected with, ix, 82;
operation, vi, 271-3;
persistency of, iv, 346-7, v, 329, vi, 155
(see also Sight)
Vis Plastica, iii, 14
Visual Hallucinations, x, 358, xi, 91
Visual Purple, of retina, xi, 96
Vital Capacity, defined, x, 339
Vital Function, tests of, x, 376-9
Vitality, of infants, ix, 352
Vital Knot, ix, 257

Vital Processes, chemical nature of, viii, 353, 355, ix, 34;
chemical control of, 167-72;
control of breathing, 256-7;
functional metabolism of, 295-6;
no energy consumed in, viii, 367;
past theories of, x, 69, 76-7, 84, 85, 86

Vitamines, viii, 362, 369-70, ix, 33-4, 35-6, 347, x, 256-68

Vitreous Electricity, iv, 258
Vitruvius, work on architecture, xvi, 98
Vividness, in associations, xi, 205
Vlacq, Adrian, xvi, 104
Vladivostok, harbor of, xiv, 267
Vocal Cords, ix, 83
Vocal Organs (see Speech Organs)
Vocations, avocations and, xi, 375-7;
choice, 276, 358-61
Vocational Guidance, xi, 358-61
Vocational Training, of veterans, x, 190

Voice, evolution of, in amphibians, xii, 170, 178;
expressiveness of tone of, xv, 144;
fear effects on, xi, 132;
modulations of, iv, 209, 232;
pitch in public speaking, 232;
quality of, to what due, 233;
range of human, ix, 99;
sound of, in dense atmosphere, 31-2;
use of, in communication, xv, 151-2
Voice Organs, in birds, xii, 248-9
Voice Production, motions of, ix, 83
Volatile Liquids, iv, 174

Volcanic Activity, distribution, iii, 100 (map), 227 (map), xiv, 314-21;
hot springs and, 143, 144;
of past ages, iii, 177, 191, 196, 197, 203, 219, 226-9

Volcanic Belts, xiv, 314-17
Volcanic Bombs, xiv, 323
Volcanic Cones, xiv, 100-2, 225;
oceanic, 277, 289
Volcanic Dust, xiv, 324;
from Krakatoa, i, 18, 57-8, iii, 101, xiv, 325;
from Tomboro, i, 360;
from various eruptions, iii, 102-3;
in atmosphere, i, 53, 57-8, 360;
in ocean, iii, 54-5, xiv, 325;
soils of, xiv, 69, 329;
temperature effects, i, 58-9, 360;
thick deposit in Colorado, iii, 229;
wind carried, xiv, 327, xiii, 344
Volcanic Earthquakes, xiv, 338-9
Volcanic Eruptions, iii, 99-103, xiv, 321-9;
earthquakes and, iii, 93-4, xiv, 338-9;
temperature effects, i, 58-9
Volcanic Islands, xiv, 277, 289, 314, 316;
new, 319
Volcanic Necks, iii, 111;
of Mount Pelee, 103
Volcanic Rocks, iii, 13, 384, xiv, 99-100;
distribution in western America, iii, 227 (map);
extrusive, xiv, 105;
land forms in, 100-5
Volcanic Soil, xiv, 69, 329
Volcanoes, iii, 99-110, xiv, 312-29;
carbon dioxide from, i, 13;
distribution of active, iii, 100 (fig.), 227 (map), xiv, 314-21;
earthquakes and, iii, 93-4, xiv, 331, 338;
energy stores and harnessing of, v, 178-80;
fire source, xv, 230;
in sea, xiv, 285-6;
materials from, 104, 323-4
Voles, xii, 285, 290
Volga River, base level of, xiv, 164;
continental character, 153
Volition, xi, 259-67 (see Will)
Volkmann, on tedium, xi, 195;
pupil of Muller, x, 118
Volta, Alessandro, vi, 18-19, xvi, 122
Voltaic Cells, iv, 272, 295-6
Voltaic Pile, vi, 18-19, 61-2, 72;
invention, xvi, 122, 189
Voltaire, messengers, xvi, 11;
naturalism of, 111, 117
Volterra, soffioni of, v, 179
Volt-coulomb, iv, 294
Voltmeters, vi, 62, vii, 153-65, 376;
ammeters used as, 167-8;
electromagnetic, 171;
galvanometers as, 179;
invention, vi, 23;
Kelvin's, 24
Volt Ratings, vi, 53;
importance, 9, 72

Volts, Voltage, iv, 280-1, 284, vi, 53-4, 57, vii, 376;
amperage, resistance and, (see Ohm's Law);
changed by converters, vi, 345-8;
dangers of excessive, 9, 72;
decrease in transmission, vii, 189;
direct current, 164;
high, in smoke precipitation, vi, 164;
high, in transmission, 159-61, 331-2, vii, 10-11;
induced and generated, 370;
magnitude, on what dependent, 139, 144-5;
measurement (see Voltmeters);
regulation, vi, 188, 328-9, 346;
regulation in automobiles, vii, 144-50;
regulation in motors, vi, 226-8;
residual, 191;
stepped up and down, 309-10;
terminal and generated, 186;
transformation, 159-61 (see Transformers);
watt-seconds in relation to, 82, 85
(see also Electromotive Force)
Voltage Regulators, vi, 188, 328-9, 346
Volume, metric units of, viii, 28;
of gases, laws, 106-8
Volumetric Analysis, viii, 291, 292-5
Voluntary Actions, factors, xi, 260-5
Vomiting, cause, xi, 39
Von Kluck, course of, xiv, 92
Vortices, atmospheric, i, 134-5;
Descartes' theory of, ii, 60
Vosges Mountains, xiv, 87 (map), 90, 117
Vowel Sounds, nature of, xi, 104;
photograph record of, iv, 234
Vries, Hugo de, on mutants, xiii, 333, 334
V-shaped Depression, i, 238, 384
Vulcan (planet), ii, 189
Vulcanizing of Rubber, xiii, 245;
sulphur used in, viii, 77, 257-8
Vulcano, dormant volcano, xiv, 317
Vulcanology, science of, xvi, 38
Vultures, xii, 260
Waialeale, Mount, rainfall on, i, 112

Waiting, slowness of time in, xi, 194, 195, 196

Wakefulness, causes of, ix, 218-19
(see also Insomnia)
Wake Robin, xiii, 176, 183 (fig.)
Wales, Britons in, xiv, 243;
geology of, 271-2;
marriage by capture in, xv, 283
Walking, act and processes, ix, 89-90, 156-8;
balance, how maintained, xi, 31;
chain reflex in, 250;
correct carriage in, x, 305, 306;
as exercise, 304, 317;
high heel effects on, ix, 69;
of children, 351;
of men and apes, xv, 58;
work equivalent, x, 305
Walking Ferns, xiii, 65
Walking Machines, v, 215-16
Walking Stick, ix, 9, xii, 107-8
Wallabies, xii, 278-9, 280
Wall, Dr., on lightning, vi, 14

Wallace, A. R., on distribution of animals, xvi, 140;
on Martian life, ii, 248
Wallis J., mathematician, xvi, 113-14, 115
Wallpack Ridge, xiv, 51

Walnut Tree, antiquity of species, xiii, 324-5;
family, 191;
petals absent, 190;
sexes in, 46, 191;
in U. S. forests, xiv, 373
Walpurgis Night, i, 184
Walruses, xii, 334-5;
in glacial period, xiv, 376
Walschaerts Gear, v, 210
Walter, Dr. B., i, 147
Walter Reed Hospital, x, 189
Walther, patron of Regiomontanus, ii, 40, 41
Wapiti, xii, 317-18;
antlers of, 316
War, "art" of, i, 306;
chemistry in, viii, 262-4;
crowd psychology in, xi, 330-1;
destructiveness of modern, v, 359;
engines of, 359-75;
inventions and, 12, 350-60, 375;
meteorology in, i, 306-15;
science and, xvi, 9;
topographical considerations in, xiv, 92-3
Warblers, colors of, xii, 245-6
War Dances, xv, 307
Warm-blooded Animals, diseases of, x, 206;
temperature regulation in, x, 250, ix, 305
Warm-bloodedness, ix, 305;
advantages, 306-7;
importance of, xii, 244, 271

Warmth, sense of, ix, 93-4, 319-20, xi, 109, 112, 113, 114

Warping (geological), xiv, 35-6, 37, 38-9

Warp Threads, v, 278-9, 281, xv, 244-5, 246 (fig.)

Warren, Dr., x, 125
Wart-hog, xii, 310
War Vessels, first steam, v, 378

Wasatch Mountains, faulting in, iii, 89, 90-2, 152;
fault scarp of, xiv, 117, 122, 124, 230;
parallel beach lines on, 207;
recent uplift, iii, 39
Washing Machines, Electric, vii, 78-82, 90
Washing Soda, viii, 135

Washington, (city), malaria reduction in, x, 300

Washington, (State), earthquakes in, xiv, 331;
forests in, 374;
lava formations, 102, 104, 318
Washington Monument, diurnal gyration, v, 71
Washington Thorn, xiii, 198 (fig.)
Wasps, xii, 125-6;
appearance in Tertiary, 104;
nests of, xv, 266
Watches, balance wheel construction, iv, 148;
historical development, v, 57, 65, 379;
mechanism, 68-72;
precision of modern, 67-8;
radium dials, iv, 380;
screened from magnetism, vi, 32
Watchung Mts., xiv, 111
Water, atmospheric content, viii, 67;
basic element (Thales), xvi, 77;
body needs and uses of, viii, 355-6, 357, 358, ix, 37-8, 173, 233, 246-7, 262, 272, 273, 274, 276;
body percentage of, viii, 348
boiling of, by cooling, iv, 168-9;
boiling point, i, 73, iv, 136, 137, 141, 168, 178;
boiling point and pressure, 170, v, 354, viii, 303;
buoyant power of, iv, 104, 105;
capillarity, viii, 37;
catalyzing power, 103;
chemical composition, 26, 39-40, ix, 26;
chemical properties, viii, 38-40, 355-6;
cleansing agent, 142;
color and taste, 40;
compounds of, 38-9, 70, 79-80, 89, 152-3;
compressibility, v, 106, 107;
cooling by evaporation of, iv, 174, v, 349-50;
critical temperature and pressure, iv, 171-2, 173;
decomposition, viii, 21, 39, 101-2, 134, 184;
density of, iv, 113;
density standard, 111, 112, 149;
distribution of, on earth, xiv, 20-5;
drinking of, and obesity, x, 275;
drinking of, at meals, ix, 229;
electrical conductivity of, iv, 296;
electrolysis of, viii, 30-1;
expansion on freezing, iv, 149-51, 163, viii, 38, xiv, 75;
fire extinguishing by, viii, 57;
fluid temperatures, ii, 244;
foreign substances in, viii, 40-1;
forest requirements, xiv, 377-8;
formed by body tissues, ix, 262;
formed as by-product of salts, viii, 115, 116-17;
freezing of, warming process, iv, 161;
freezing of, while boiling, 169;
freezing point, i, 73, 136, 137, 141, 173;
freezing point, lowered by alcohol, viii, 299-300;
geological work (see Streams, Rivers, Lakes, Ocean);
grass requirements, xiv, 381;
ground (see Ground Water);
hardness of, viii, 151-2, 318, 377, iii, 126, xiv, 147;
heat capacity of, iv, 155, 162-3, 186;
heat conductivity, 176, 179;
heat convection in, 177-8;
heat developed in formation, viii, 95-6;
heating of, mechanical equivalent, iv, 49-50, v, 350;
height of rise in vacuum, iv, 27;
hydrogen produced from, viii, 30-2;
hydrolysis, 39, 217-18;
imperviousness of clay to, xiv, 137;
importance, viii, 36;
in animal body and plants, 348, 355-6;
in carbohydrates, 223, 224;
in carbon-hydrogen cycle, 350;
in protoplasm, ix, 37-8, 282;
in various foods, viii, 362, 363, 364, 365;
infant's need of, ix, 350;
interestingness of, xvi, 14;
ionization of, viii, 123;
"juvenile," xiv, 151-2;
kinetic energy, v, 84-5;
latent heat of, iv, 161, 174, 188, v, 169, 353-4, viii, 38;
laws of, widely known, vi, 106;
mechanical uses (see Hydraulic Machinery);
machines for raising, iv, 26-7;
men's need of, xiii, 101-2;
metabolism affected by, ix, 37-8;
metric measurements of, iv, 111, 112;
a mineral, iii, 308;
mixtures at different temperatures, iv, 153-4;
mixtures with ice, 160-1, v, 353-4;
necessity of, to life, x, 275, ix, 37-8, xi, 66, xiii, 101-2;
of chemical union, viii, 38-9;
of crystallization, 38;
of limestone regions, xiv, 147;
ore deposition by, viii, 199;
origin of life in, ii, 243, 244, xvi, 78;
origin on earth, iii, 160, 163;
oxygen in solution, viii, 35, ix, 182;
photographing objects under, i, 47-8;
physical properties, viii, 37-8, 40-1, 355;
plant fertilization by, xiii, 123, 149-52, 158-9, 160, 161, 165;
plants' storage of, 28, 41-2, 106-7, 378, 379, 380;
plants' use of, viii, 335, 337-8, 347, xiii, 90-6, 101-9, xiv, 65, 377-8, 381, ix, 26-7;
power in atoms, vi, 115;
pressure of, iv, 117-19, v, 94-5, vi, 47-9, 56;
produced by combustion or decay, viii, 61;
produced by volcanoes, iii, 107;
purified by ozone, vii, 354-5;
purification by dissolved oxygen, viii, 40, 111;
purity of flowing, iii, 121;
rate of flow, vi, 68-9, 70-1;
reflection of light by, iv, 373-4;
reflection of objects in, 337;
refraction of light by, 323, 326-7, 331, 373-4;
resistance, v, 190-2;
rock-weathering by, iii, 22-3, 24-6, viii, 194-5;
seed dispersal by, xiii, 346-8;
softening of, viii, 135, 152, 323-4;
soil, xiii, 92;
solvent action and solutions in, viii, 37, 111-13, 120-1, 217;
sound transmission by, v, 107, 108;
sound velocity in, iv, 201;
specific gravity basis, 109, 111;
specific heat of, 155, viii, 37;
states of, iv, 22, 131, 139, 151-2;
supercooled, viii, 113;
temperature in steam engines, v, 139-40;
temperature of greatest density, iv, 149, v, 350;
terrestrial, circulation and sources, xiv, 134-5, 151;
therapeutic uses of, x, 85, 383;
transparency in Lake Tahoe, iii, 154;
weight of, iv, 117, 149, v, 94, vi, 80-1, 147;
within the earth, iii, 109-10, 113-29

Water-bearing Strata, excavating through, v, 116-17

Water Birds, xii, 250-9;
feathers of, 244;
sleeping of, xi, 287
Water Boa, xii, 216
Water Boatmen (insects), xii, 114
Water Bugs, xii, 114
Water Chestnut, source, xiii, 266
Water Clocks, ancient, v, 59-63
Water-cooled Engines, v, 159-61
Water Cress, taste, xiii, 197
Water Dogs, xii, 171
Water-dripping Plants, xiii, 107-8
Water Drops, atmospheric, i, 91-2, 93, 95;
phenomena due to, 150, 166, 175, 177, 183
"Wateree," U. S. S., xiv, 337
Waterfalls, caused by Ice Age, iii, 242-3;
energy of, iv, 81;
in glacial valleys, xiv, 57;
in homogeneous rock, 132-3;
in old and new regions, iii, 33-4, xiv, 48, 49, 57, 159;
types, iii, 44-50
Water Gaps, xiv, 98
Water Glass, viii, 141
Water Hammer, in pipes, v, 84, vi, 254, 364
Water Hemlock, seeds, xiii, 201
Water Jets, digging with, v, 88;
dredging with, 258;
power, 80;
propulsion of boats by, 190;
vena contracta of, 89-90
Water Lilies, Amazon, xiii, 359-60;
class of, 196

Waterloo, Napoleon's indigestion before, ix, 238;
weather conditions, i, 307
Watermelon, xiii, 54, 227;
water content, viii, 365
Water Meters, v, 87-8
Water Organ, v, 110-11
Water Pipes, bamboo stems as, xiii, 183;
bursting of, iv, 151, xiv, 75;
electrical thawing, vii, 336-9;
electrolysis, 188;
rate of flow in, vi, 71;
water hammer in, 254, 364, v, 84
Watering Places, xiv, 145
Water Plethysmograph, xi, 284
Water Power, coal and, xiv, 31, 191;
compressing air with, v, 89-93;
discovery of, xv, 240-1;
early and present use, v, 75-6, 173, xiv, 31;
electricity from, vi, 162-3, 351-2, 361-70;
future possibilities, v, 83-4;
gravity the real power, 76-7, 139;
growing use of, viii, 267, 283;
high head importance, v, 77;
in mountain countries, xiv, 242;
use on farms, vii, 233-4;
"White Coal," v, 174

(see also Hydraulic Machinery, Hydroelectric Plants, Water Jets, Water Wheels)

Waterproofing, by rubber, xiii, 245
Water Ram, v, 84-6
Water Scorpions, xii, 114
Watersheds, Atlantic-Pacific, xiv, 189-90;
in young and old regions, 158, 161
Water Snakes, xii, 217-18
Water Solubles (vitamines), x, 260, 261, 262
Waterspouts, i, 138, 384;
cores, 299;
lifting power, 356;
superstitions, 335
Water Supply, common sources, viii, 317-18;
from wells, iii, 118, viii, 317-18, xiv, 139-40;
of American cities, viii, 317, 318, 320, 322, xiv, 140-1;
pollution and purification, viii, 41, 317-24, xiv, 139-41;
purification by chlorine, viii, 86, 321;
purified by compressed air, iv, 130-1;
snow sources, i, 118;
typhoid contamination of, x, 287
Water Table, iii, 113, 118, xiv, 136;
rise of, i, 355
Water-tube Boilers, v, 140
Water Turbines, v, 82-3, vi, 361-2, 363-4;
efficiency, v, 170;
at Keokuk Plant, 81-2, 82-3;
of Niagara Power Plant, vi, 372-3, 374-5

Water Vapor, atmospheric, i, 10, 11, 14-15, 76, iv, 183;
precipitation, i, 90-6, 113, 115, 120, 121;
need of nuclei for condensation, viii, 113;
saturated pressure of, iv, 168, 169
Water Wheels, early use, v, 19, 75, 76;
energy used by, iv, 181;
former and modern types, v, 76-7;
invention of, xv, 240-1
(see also Pelton Wheels, Water Turbines)
"Waterwitch," steamboat, v, 190
Water Witches, iii, 123, 124
Water Yam, xiii, 89-90
Watkins Glen, iii, 44, 243
Watson, Sir Thomas, x, 112
Watson, Prof., asteroids of, ii, 256-7
Watt, James, power unit named for, iv, 285;
steam engine, v, 44, 47, 144-6, 376, 377, xvi, 125

Watt, Sir George, book on Indian plants, xiii, 266

Watt, power unit, iv, 80, 285, 310, 312, vi, 84-5, vii, 376;
method of ascertaining, vii, 166;
value in candlepower, iv, 352
Watt-hour, iv, 312, vi, 82;
erg and calorie equivalents, vii, 382
Watt-hour Meters, vii, 174-7
Wattmeters, vii, 172-4, 376;
electromagnetic, 171
Watt-second, vi, 82, 84, 85
(see also Joule)
Wave Length, iv, 196, 213, 214 (fig.), 384
Wave Meters, vii, 292-5
Waves, Ocean (see Ocean Waves)
Waves (vibrations), defined, iv, 196, 384
(see also Light Waves, Sound Waves, etc.)
Wax Candles, viii, 246, 247
Waxes, viii, 245-6, 350

Weak-Mindedness, facial expressions of, xv, 63, 64 (fig.)

"Weaning" Treatments, xi, 248

Weapon Salve, x, 79

Weapons, evolution of, v, 12-13, xv, 102-10, 190-2, 205-21

Weariness, indigestion from, ix, 241
Weasel Family, xii, 347-51
Weasels, xii, 348-9;
storing of food by, 292
Weather, aeronautics and, i, 284, 285;
atmospheric pressure and, 237-8, 241-2;
business dependence on, 261-70;
climate and, 199;
clothing in relation to, x, 309-10;
"comes from west," xiv, 350;
control of animal and plant life, i, 254;
correlation studies, 253;
crops and, 245-50, 252-3;
cycles, 242;
elements and how observed, 70-89;
heights of phenomena, 17, 18;
human effects, 316, 323-4, 330-1;
military importance, 306-15;
modern commenting on, 66;
moon's influence, ii, 201;
predictions for future eclipses, 217;
pressure areas and, i, 135, 218, 237-8, xiv, 349-50;

"recurrence," i, 363;
solar radiation and, 218-19, ii, 186-7, iv, 194;
sun-spots and, i, 16, 242, ii, 186;
variety in relation to efficiency, xiv, 357;
world-wide interrelations, i, 218, 241-2
Weather Bureau (see U. S. Weather Bureau)

Weather Forecasts and Forecasting, i, 224-6, 236-44;
advertising and, 265-6;
aeronautical, 18, 304-5;
agricultural, 256-7;
basis, 135;
frost, i, 260;
history of, xvi, 102, 177;
kites and balloons in, i, 22;
"odds," 314;
rainbows in, 177;
small progress in art, 382;
sunrise and sunsets in, 166;
United States, 216-17
(see also Weather Predictions)
Weather Glass, i, 70
Weather Instruments, i, 68-89
Weather Insurance, i, 269-70
Weather-Making, i, 332-45
Weather Maps, i, 225-36;
"flat," 239, 372;
marine, 273-6;
shipboard, 281;
winds on, 125-6, 134

Weather Observations and Reports, i, 66-89, 213-23;
aeronautical, 304-5, 314;
earliest instrumental, 201;
humidity in, xiv, 353-4;
marine, i, 274-6, 280-2;
used in crop forecasting, 251-2;
World War, 310, 314
Weather Predictions, long range, i, 241-4;
value to farmers, 249-50
Weather Prophets, distribution, i, 243
Weather Proverbs, i, 106, 177
Weather Vanes, ancient, i, 68;
common and scientific, 82
Weather Wells, i, 354, 384

Weathering of Rocks, iii, 22, 384, viii, 194-5, 338;
agencies and processes, iii, 22-9, xiv, 41-3, 62-4, 75-9, 105-6;
determined by character and arrangement of rocks, 44, 79, 130, 133;
in deserts and arid regions, iii, 23, 72, xiv, 41-2, 62, 69, 77-9;
on mountains, iii, 23-4, xiv, 40, 233;
plutonic rocks, 105-6, 107, 110, 112-13

Weaving, historical development of, xv, 243, 244-7;
pattern-making, v, 280-2;
threads, 276, 278-80
Weber's Law, xi, 184-5
Webs, of spiders, xii, 94, 95-6
Webster, Daniel, brain weight, xv, 39
Wedding Presents, xv, 285
Weddings, attendants at, origin of, xv, 282
Wedge, v, 37;
discovery of use, 15;
form of inclined plane, iv, 90;
friction in, 93
Wedge (meteorology), i, 238, 384
Weeds, origin in U. S., xiii, 353-4
Weedy Plantain, xiii, 88
"Weeping Trees," i, 351
Weeping Willow, xiii, 271-2
Weft Threads, v, 278, 280
Wegener, Dr. A., i, 192
Weight, iv, 58, 74, 99, 101;
defined, vi, 81, xvi, 130;
diminished by earth's rotation, iv, 74-5;
errors in perception of, xi, 184-5;
latitude and, ii, 69, iv, 101, 102, xvi, 130;
loss of, in fluids, iv, 104, 105, 106, (fig.), 107;
mass and, 84-5, 110, xvi, 130;
measured by spring balance, iv, 102;
measurement of, by displacement, 103-4, 105;
of gases, gram-molecular method, viii, 109;
units of, iv, 46, 283-4, viii, 28

Weight (bodily), at different ages, ix, 31, 32 (diagram);
metabolism in relation to, x, 271, ix;
reduction of, 302;
rate of reduction by fasting, x, 275

Weight Arm, in machines, v, 22, 26, 31, 32, 33

Weights and Measures, British and metric units, iv, 45-6, 69-70;
practical units, 283-4;
scientific standards, xvi, 129-30
(see also Units)
Weismann, germ plasm theory, x, 230;
on adaptations, xvi, 152
Welding of Metals, i, 33;
electric, iv, 312;
Goldschmidt method, viii, 155
Wells, airlifts in, iv, 130;
artesian, iii, 118-19, xiv, 12, 138;
blowing, i, 353-5, 368;
drilling of deep, iii, 119-21;
drying of, xiv, 136;
gases and minerals in water, 141-2;
Green's drive, v, 380;
locating of, iii, 123-6;
pumping systems for deep, v, 114-15;
sanitary aspects, iii, 121-3, xiv, 139-40;
source of, 138-9;
sunk in granite, 137;
water supply from, iii, 118-19, viii, 317-18
Wells, E. I., on railroads, i, 267
Wells, Horace, x, 124, 125, xvi, 185
Wells, Spencer, xvi, 184
Welsbach Gas Mantles, vi, 264, viii, 252;
invisible rays, xvi, 192
Welsh Language, xv, 162

Welsh People, in Mediterranean Group, xvi, 49;
mountain isolation of, xv, 130
Welts, hypnotic production, xi, 317
Welwitschia Mirabilis, xiii, 380-1
Wentletraps, xii, 71
West Africa, beetles of, xii, 124;
crocodiles of, 199-200;
coast of, xv, 136;
forests of, xiv, 366, 368-9;
hanging valleys in, 58;
harmattan of, i, 134;
monkeys of, xii, 379;
monsoons, i, 131;
python of, xii, 214;
river shrew of, 367;
sleeping sickness, x, 169;
tornadoes of, i, 137
Western American Volcanic Belt, xiv, 315
Western Forest (U. S.), xiv, 373-4
Western Pacific Volcanic Belt, xiv, 315-16
Western Union Telegraph Co., vii, 107-8, 112;
early weather forecasts, i, 216
West Indies, boa constrictor of, xii, 215;
clove production, xiii, 262;
coffee in, 233;
concordant coasts of, xiv, 249;
coral reefs in, 305;
earthquakes in, 331;
hurricanes, i, 136, 375;
hurricane reports, 280-2, 309;
mongooses in, xii, 352;
nutmeg production, xiii, 262;
poisonous snakes, xii, 234;
sea-shells of, 73;
sharks of, 143;
sponges of, 32;
spurge, xiii, 30-1;
vanilla production, 259;
volcanoes of, xiv, 316

Westerly Winds, region of prevailing, i, 128, 129

Westinghouse, George, air-brake, v, 130, 380

Westinghouse Electric Co., machinery for Niagara Plant, vi, 374, 375, 376

Westminster Abbey, weathering effects, iii, 22

West Virginia, natural gas, iii, 355
Wet Bulb Thermometer, i, 78-9, 318, 384
Wetness, exposure to, effects of, x, 239;
sensation of, xi, 128
Wet Steam, v, 140
Whalebone, xii, 298
Whales, xii, 297-9;
sawfish and, 149;
squids and, 80
Whale's Food, xii, 19
Whaling Industry, aerial patrol in, i, 48
Wheat, ancestral home, xiii, 182, 221;
economic importance, i, 263, xiii, 208;
food value, viii, 364, x, 259, 261, 262, 267, 278, 279;
fruit for seed dispersal, xiii, 56;
germination of seeds, ix, 16-17, xiii, 211;
history and forms, 210-11;
in grass family, 179;
Mediterranean source, xiv, 382;
phosphate requirements, 67;
protein in, xiii, 95;
rust, 13;
snow and, i, 253;
stalk stiffening, viii, 337;
starch made from, 243;
time required to produce, v, 249;
vitamines in hulls, ix, 35, 36
(see also Winter Wheat)
Wheatstone Bridge, iv, 301, vi, 80
Wheel and Axle, v, 31-3;
action of, like lever, iv, 89
Wheel Lock, xv, 217
Wheeled Vehicles, use on farms, v, 215
Wheels, centrifugal force of, iv, 71;
discovery and development of, xv, 241-3;
evolution of, v, 16-17, 205;
form of lever, 21, 28;
friction, 204;
friction-saving by, 205-6;
large and small, 206;
not found in nature, 16, 215;
tendency to turn on center of gravity, 150;
in transportation, 214-15
Whelks, xii, 72
Whippoorwills, family of, xii, 267;
feathers about mouth, 244
Whirlwinds, dust, i, 60
Whiskey, making of, viii, 250
Whispering Galleries, iv, 239
Whistles, policeman's, iv, 220;
siren, 205
Whistling, impossible in caissons, iv, 32
White (color), reflection of light by, x, 309
White, Andrew D., on comets, ii, 84
White, Charles, x, 92
White, D., quoted, iii, 202, 343
White, I. C., anticlinal theory, iii, 352
White, Maunsel, v, 55, 383
White, Orlando E., xiii, 221
White Ants, xii, 110
White-blood, metabolism in, x, 272
"White Coal," v, 76, 174
White Corpuscles, ix, 182 (fig.), 184-8;
germ destruction by, 185-7, x, 197, 209-10;
passage through capillary walls, ix, 194
Whiteface, Mount, spring on, iii, 117
Whitefish, xii, 154, 159
White Flies, xii, 112

White Flour, vitamines absent in, x, 267, ix, 35

Whitehead Torpedo, v, 380
White Heat, temperature of, iv, 361
White Lead, viii, 162, 265
White Light, iv, 364;
composition, Colors, i, 165, iv, 357-9, 366-7, vi, 282, viii, 301, ix, 115, 3579, xvi, 119;
hands and face in, iv, 364-5
White Mts., Arctic species in, xiv, 377;
club mosses of, xiii, 305;
in Mesozoic Era, iii, 232
White Pine, in northern forests, xiv, 372;
region of, xiii, 368
White Plague, x, 290, 294
White Race, xv, 32;
beards in, 38;
brain weight, 41;
characteristics indefinite, 35-6;
disease immunity and susceptibility, 48, 49-50;
eyes, color of, 37;
facial angle in, 45;
hair, color and form of, 37, 38;
in tropics, i, 327, xiv, 344, 356-7, xv, 49-50;
jaw angle of, 44;
language relationships, 161-3;
light and dark divisions, 37;
measles in, 48;
nose index and nostril shapes, 45, 46;
savages' ideas of, 334;
separate origin theory, 70;
skull index in, 42;
skull capacity, 41
White Rainbows, i, 176, 384

White Rats, protein experiments on, ix, 287-8, 288

White Swelling, x, 78
"White Way" Lighting, vi, 279, vii, 339-40
White Whales, xii, 297
Whitman, Walt, "Song of Myself," xi, 336
Whitney, Eli, v, 269;
cotton gin, 269-71, 376, xiii, 237-8;
milling machine, v, 47, 378;
standard muskets, 49-50

Whitney, Mount, observatories on, ii, 144, 149

Whitney, Professor, on emphasis, xv, 144;
on language changes, 157
Whittlesey, Lake, iii, 148
Whole Wheat Bread, vitamines in, x, 267
Whooping Cough, consumption from, x, 292;
germ of, 216

Wickam, H. A., "botanical specimens" of, xiii, 247

Widal Reaction, x, 216
Wilberforce Spring, iv, 83-5
Wilcox & Gibbs Machine, v, 285
Wild Arum, fertilization, xiii, 153
Wild Asses, xii, 308
Wild Boar, xii, 310;
in Cro-Magnon paintings, xv, 114
Wildcats, xii, 356
Wild Dogs, xii, 345
Wild Ducks, seed dispersal by, xiii, 340-1
Wilderness of Judæa, xiv, 121
Wild Horse, xii, 306-7
Wild Mustard, origin in U.S., xiii, 353-4
Wild Ox, xii, 330-1
Willets, xii, 262
Will or Volition, xi, 259-67;
hypnosis and, 317, 318;
motor character, 61;
source of energy of, 33
William the Conqueror, at Salerno, x, 36, 37
Willamette River, navigability of, xiv, 195
Williams, Prof. Samuel, ii, 211;
quoted, i, 201
Williams, Wells, on Chinese astronomy, ii, 21

Williamson, chemical work, xvi, 133-4, 162, 165

Willis, Thomas, xvi, 108

Will-o'-the-Wisp, i, 346-9

Willow Trees, antiquity of species, xiii, 324-5;
family, 191;
fertilization, 122;
origin and product, 244;
petals absent, 190;
seed dispersal, 343;
sexes in, 47, 191;
sprouting of, 166
Willughby, xvi, 126
Wilson, A. B., sewing machine, v, 284-5, 379
Wilson, T. L., xvi, 190-1
Wimhurst Influence Machine, vi, 301
Winch, iv, 90-1
Winchell, A. N., i, 55
Winchester, James, quoted, i, 360
Wincing, origin, xi, 133

Wind, Winds, cause and general system, i, 124-9, xiv, 347-51;
climate determined by, 345-7;
complex structure, i, 292-8;
defined, x, 384;
direction, how observed, 82;
drying power, 77;
due to sun, v, 177, xiv, 32;
dust-carrying by, i, 52-5, iii, 71, 73-5, xiv, 77, 327;
eddies and updrafts, i, 53;
force measurement, 83-4, 294-6;
force in relation to isobars and altitudes, i, 126;
geological work, iii, 71-5;
gusts, i, 295;
human control, i, 332, 333;
in aeronautics, 284-6, 289-300;
lifting effort on kites, iv, 76 (fig.);
lightning and, i, 148;
local names, 132;
ocean, 271-6;
ocean currents caused by, xiv, 303;
plant fertilization by, xiii, 118, 123, 148-9;
power to blow objects aloft, i, 356;
pressure areas and, i, 124-6, 127-9, 134-5, 218, xiv, 349-50;
pressure due to inertia, v, 234;
projectiles and, i, 312-13;
rainfall and, 111;
rock destruction by, iii, 72-3, xiv, 41, 45, 62, 77, 233;
sailing against, iv, 77 (fig.), v, 182, 186-8;
seed dispersal by, xiii, 58-9, 156, 340, 343-6;
soils deposited by, iii, 73-4, xiv, 71-5;
sound and, i, 187, iv, 210-11;
superstitions, i, 334-5;
topography and, 292, 294 (fig.), 296-7;
types, 130-9;
use of power, 37-8, v, 75, 111, 173, 182;
velocity and force, i, 83, 84, 137, 138;
vertical, 293;
waves caused by, xiv, 299;
weather and, i, 237-8, xiv, 349-50;
worship of, by Polynesians, xv, 342
Wind Aloft, i, 384
Wind Aloft Maps, i, 230, 231, 233
Wind Charts, i, 206, 271-3

Wind Gaps, iii, 39, 38 (fig.), xiv, 58, 98, 169

Wind Instruments, iv, 231;
development of, xv, 316-17
Windmills, v, 75, 111;
modern use, i, 37-8
Windpipe, cartilage in, ix, 57;
connections and parts, 255
Wind Rose, i, 273-4, 384
Wine, alcohol in, how measured, iv, 113;
flavors of, viii, 248-9;
pasteurization of, x, 139-40;
religious uses, primitive, xv, 352
Wine Making, viii, 248-9;
Pasteur's discoveries, x, 138, 139-40
Wine Palm, xiii, 53
Winged Fruit and Seed, xiii, 58, 345-6
Wings, of birds, xii, 247
Wings, of flowers, xiii, 47-8
Wing Shells, xii, 73-4
Winkles (shellfish), xii, 72
Winnepeg, Lake, iii, 144
Winter, effects on life, xi, 51;
human efficiency in, i, 323;
keeping warm in, ix, 309, 312;
land and sea winds in, xiv, 346;
mild and severe, how determined, 350;
"old fashioned," i, 200-2;
thunderstorms, danger of, 156
Winter-Days, temperature, i, 205, 384
Wintergreen, origin, xiii, 255
Wintergreen Plants, xiii, 202
Winter Provender, of rodents, xii, 292-3
Winter Wheat, best time to plant, i, 256;
snow and, 253
Wireless Communication, vii, 258-98;
condensers in, vi, 303, 304;
dependent on simultaneous reactance, 171;
hot-wire ammeters in, vii, 163, 164
(see also Radio)

Wireless Control, of aeroplanes and ships, vii, 283-4

Wireless Signals, in aeronautics, i, 291, 292, 302

Wireless Telegraphy, iv, 313-16;
alternating currents in, vi, 168;
conditions of transmission, vii, 272-3;
detectors, 268, xvi, 191-2;
history, 191;
induction coils in, iv, 305, 313, 314;
resonance in, 226;
strays or static, i, 162-3;
theory for amateurs, vii, 285-98;
vacuum tubes in, vi, 125, vii, 276-80;
weather reporting by, i, 257, 269, 280-2, 315;
in World War, vii, 283
(see also Wireless Communication)
Wireless Telephony, iv, 315-16;
aeronautical uses, i, 44-5, 302;
alternating currents in, vi, 163;
current conversion, 339-41;
development of, vii, 280-3;
distress signals, 284;
theory for amateurs, 285-98;
vacuum tubes in, vi, 125, 339-41, vii, 276, 278, 279, 280;
weather reporting by, i, 257;
in World War, vii, 282-3
(see also Wireless Communication)
Wires, current-capacity table, vii, 58;
leakage, 10-11;
measure (circular mils), iv, 282-3;
measure (mils), vi, 77, vii, 373;
resistance of, iv, 281, 282-3, vi, 79;
sizes and kinds in transmission, vii, 20-4;
standard tables, (copper), 378-81;
types of insulation, 58
Wireworms, xii, 124
Wiring, interior, vii, 51-72;
exterior (see Overhead, Underground Transmission)

Wishbone, of birds, xii, 247
Wisby, in Hanseatic League, xiv, 282
Wisconsin, drainage studies in, xiv, 131;
drumlins of, iii, 69, xiv, 60;
Ice Age in, iii, 239;
lakes of, xiv, 200;
terminal moraines in, 59
Wise, John, rip panel inventor, v, 224
Wiseman, Richard, x, 78
Wishes, dreams from, xi, 293, 299-300, 301-2;
suppression of, 140-2, 257
Wistar, Casper, x, 116
Wit, psychology of, xi, 350-7
Witchcraft, former theories of, x, 357, 360
Witches, colonial ordeals for, xv, 373
Witchhazel, origin, xiii, 255
Witch-Hazel Plant, seed dispersal, xiii, 339

Witnesses, influence of forms of questions, xi, 308-10;
untrustworthiness, 103, 168
Woevre, France, xiv, 91
Wöhler, Friedrich, x, 126
Wolf, astronomer, ii, 134
Wolff, Caspar F., xvi, 118
Wolf-Rayet Stars, ii, 116
Wollaston, William Hyde, xvi, 122, 162;
spectrum studies, ii, 111, 112
Wolverine, xii, 348-9
Wolves, xii, 340-2;
dogs and, 344;
ears of, 346;
in Great Britain, xiv, 273;
Tasmanian, xii, 277
Wombat, xii, 278
Women, basal metabolism of, x, 271;
bearing of pain by, ix, 87;
brain weight in, xv, 39;
color-blindness in, ix, 116, 340-1;
dress of, x, 309;
ear-rings of, xv, 259;
food requirements, viii, 367;
heart rate in, x, 334;
height of, xv, 38;
modesty and immodesty in dress, 254-5;
painting of, 256;
skull capacity, 40;
susceptibility to temperature changes, x, 240;
voice tones of, ix, 99
Wonder, in various sentiments, xi, 146, 147
Wood, chemical material of, viii, 44;
decay of, xiii, 71;
distillation for wood alcohol, viii, 214;
electrical conductivity, iv, 259;
flame of burning, viii, 57;
heat conductivity, iv, 176, 177;
percentage of carbon in, viii, 44;
petrified, iii, 15-16;
sound velocity in, iv, 201;
storage appliance of plants, xiii, 96;
use as food, ix, 24
(see also Heartwood, Sap wood)
Wood, Henry Wise, v, 383
Wood Alcohol, viii, 214;
flame of, 60;
used as denaturant, 250
Wood Ashes, lye from, viii, 276;
potash in, 279, 343, 344, xiv, 67
Woodchucks, xii, 295
Woodcocks, xii, 263
Wood Lice, xii, 82
Woodpeckers, xii, 267;
mating of, xv, 276-7;
toes of, xii, 265;
use of tools, v, 11

Wood Pulp, in paper making, v, 290, 292-5, 380

Wood Sorrels, leaves, xiii, 88-9, 113
Woodward, Dr. Robert S., ii, 147, xvi, 126
Woody Tissue, composition, xiv, 65
Woof, of woven goods, v, 278, xv, 244

Wool, as clothing material, x, 307, 308, 309, ix, 311;
chemical properties and manufacture, viii, 256;
dyes of, 259;
electrification of, iv, 257, 258, 259;
humidity effects in manufacture, i, 78;
removal of cotton from, viii, 255;
warmth, to what due, iv, 178
Wool Grass, xiii, 182 (fig.)
Wool-pack Clouds, i, 101-2, 384
Woolwich Observatory, founding, xvi, 127

Woolworth Building, elevator system, v, 134-5;
height of tower, 79;
flood lighting, vi, 283
Wordsworth, paradox of, xi, 247
Words, changes in meanings of, xv, 157;
double meanings, 158-9;
inadequacy in feelings, 143;
origin of various, 153-4, 157, 161

Work (labor), conditions of, importance, xi, 361-2;
daily amount in calories, ix, 297;
daily amount in foot-tons, x, 305;
effect of distractions, xi, 277;
fatigue and capacity for, x, 246, 247;
fatigue from new, ix, 81;
fatigue in pleasant and unpleasant, xi, 274-6, 277-8;
food energy consumed by, viii, 367;
planning of, xi, 377-8;
rest periods and efficiency, 363
(see also Vocations)
Work (mechanics), iv, 37, 38;
accomplished by inequalities, viii, 168;
energy and, iv, 37-40, 78-88;
heat relations to, 189-91, 193;
measurement and units, 78, 79-80, 189-90, vi, 81-2, 84;
rate of, iv, 80

(see Power)

Workers, food requirements and energy of, viii, 367;
instruction of beginners, xi, 363-5;
interest of, 376;
jobs and, 358-61;
tool adjustment to, 362

World War, aeronautical development, i, 40-1, 284, 285, iv, 10, 107;
aeronautical weather services, i, 304-5;
aeroplane accidents, x, 246;
aeroplane machine guns, v, 107;
aeroplane mapping, i, 45;
aeroplanes, luminous glories seen, 185;
aftermath of, x, 188-9;
artillery phenomena, i, 193-4;
artillery vs. armor, v, 368;
big guns, v, 368-71;
bombardment of Antwerp, i, 191;
cannonading heard at distances, 188;
care of disabled, (U. S.), x, 188-91;
chemical warfare, viii, 262-4, x, 186-8;
chemical warfare service device, viii, 283;
chemistry in, xvi, 159;
commerce destruction in, xiv, 306;
cultural setback by, xv, 30;
dried foods in, viii, 371;
dye industry in, 253;
electricity in, vi, 10;
flood lighting, 283;
flying machines, v, 233;
French forests in, xiv, 239;
gas masks, viii, 48;
German aircraft at beginning, x, 40;
German lack of jute bags, xiii, 241;
German plans on two fronts, xiv, 91-2;
German torpedoes, v, 374;
Germans called Huns, xi, 22;
Germany's nitrate needs, xiv, 66;
helmets and armor in, xv, 221;
hysterical phenomena in, x, 363;
ignorance of southern mountaineers in, xv, 131;
influenza pandemic, x, 294-5;

Italy in, xiv, 244-5, 252-3, Italy in, xv, 138;
invasion of France and Belgium, topographical considerations, xiv, 88-93;
inventions, v, 360, 384;
jaundice in trenches, x, 201;
Liberty engines, v, 53-4;
machine guns, 363-8;
Marne retreat incidents, xi, 286-7;
medical achievements of, x, 176-91, 384;
meteorology in, i, 290-1, 307-15;
mirages in Mesopotamia, 173;
motors used, direct current, vi, 239;
nitrogen needs and production, i, 34, 36, viii, 246, xiv, 66;
pilot balloons, i, 22;
potash dearth and supplies, viii, 143-4, 279, 344, xiv, 67;
projectiles and shells, v, 372;
rain in battles, i, 338;
Russian bison destroyed in, xii, 329;
Russian elk destruction in, 318;
scientific progress in, iv, 10-11, xvi, 9, 195;
scurvy in, x, 265;
searchlights on fleets, iv, 352;
sleeping sickness epidemic, x, 301;
smoke screens, viii, 87;
sound-ranging, i, 313, iv, 201-2;
sphagnum use in, xiii, 160-1;
stereograms in, xi, 180-1;
submarines, v, 198, 200-1;
submarine spotting, i, 47;
sulphuric acid importance, viii, 78-9, 80;
surgery in, x, 181-3, 381-2;
Switzerland in, xiv, 243-4;
tanks, v, 218;
tetanus infection in, x, 299;
trench fever in, 202;
tuberculosis in France, 175;
typhoid fever in, 217, 288;
vitamine foods lacking in certain countries, 260;
volcanic power in Italy, v, 179-80;
well-poisoning in, xv, 228;
wheat in rationing, viii, 364;
wireless operations, vii, 282-3;
"Who won it?," v, 300;
wood as food in, ix, 24;
Zeppelins and captive balloons, v, 227
World Weather Bureau, i, 221
Worm Gears, v, 37 (fig.), 88
Worms, xii, 44-5, 50-6;
classification, iii, 259;
earliest tracks, 263, 270;
power of distinguishing light, ix, 105;
regeneration in, xii, 170;
sea, 18, 23
Worms (disease), x, 200
Worry, feeling of, ix, 153-4, 167;
hardened arteries from, x, 335;
indigestion from, ix, 165, 167, 240-1

Wound-Rotor Induction Motor, vi, 245, 248, 256

Wounds, antiseptic treatment of, x, 145-6, xvi, 182-3;

Carrel-Dakin treatment of infected, x, 181-3, 382;
former treatment, 40, 43, 54-5, 59, 78-9;
healing of modern surgical, 123;
painlessness to soldiers, xi, 119, 120;
Paré's treatment of, 55, xvi, 108;
radiation treatment of septic, x, 384
Wound Suckers, x, 91, 105
Wove Paper, v, 296
Woven Fabrics, threads of, v, 276, 278
Wright, Sir Almroth, x, 218

Wright, Orville and Wilbur, v, 231-2, 237-8, 383-4;
early flights, i, 300
Wright, Thomas, ii, 350, 367, 380
Wright Machines, v, 232, 236, 237-8
Wrigley Triplets Sign, N. Y., vii, 340-1
Wrist, bones of, ix, 67, 68 (fig.);
pulse in, 211

Writing, development of, xv, 164-79, 325, xvi, 60;
by telegraph, vi, 98;
remarks on art of, ii, 10;
reflex actions in, ix, 157

Written Language, association principle in, ix, 152;
importance to man, 153
Wrong, original meaning, xi, 190
Wrought Iron, v, 317, viii, 158-9
Wyberd, on corona, ii, 221
Wye Connections, vi, 209, 318, 325
Wyoming, badlands of, xiv, 82;
cattle ranges, 222-3;
dike systems, 106-7;
marine fossils in, iii, 82;
volcanic fields, xiv, 318
Xanthine, viii, 230
Xenon, in atmosphere, i, 11, 12;
symbol and atomic weight, viii, 383
Xenophanes, on fossils, iii, 14
Xiphosura, xii, 81
X-ray Analysis, of crystals, viii, 313
X-ray Photography, iv, 55, 320-1;
uses of, vii, 253-4, x, 222, 372-4

X-rays, iv, 317-21, vii, 249-57, x, 184-6, 254, 383;
discovery of, iv, 55, 317, x, 183-4, xvi, 192-3;
fluorescence produced by, iv, 320, 378-9;
invisibility, 319, 378;
transmitted through æther, vi, 119, 269;
vibration frequency, iv, 379, vii, 260
X-ray Spectra, viii, 183, 309
X-ray Tube, iv, 319, vii, 251-2;
operated by induction coils, 244;
static generators for, 245
Xylene, from coal tar, viii, 253
Xylols, viii, 235
Xylophone, iv, 224
Yaks, xii, 330
Yakutat Bay, Alaska, xiv, 334-5;
faulting in, 114, 334-5
Yakutsk, Siberia, i, 210
Yale College, founding, xvi, 127
Yampa River, xiv, 166, 168, 175
Yams, origin and antiquity, xiii, 224;
water, of Madagascar, 89-90
Yapocks, xii, 276
Yard, unit of length, iv, 45, 69;
value in meters, 46, 70
Yarn, grading of, v, 272;
making and weaving of, 268, 272-82
Yawning, as fear effect, xi, 132
Yaws, racial susceptibility to, xv, 50, 51
Y-connections (see Wye)
Year, beginning of, in ancient Egypt, ii, 26;
in Cæsar's calendar, xvi, 98;
length fixed by Hipparchus, 11, 32;
length in ancient Egypt, xvi, 70;
measurement of, iv, 15;
without a Summer, i, 359-61, 361-2
"Yearning of Bowels," xi, 64, 131, 160
Yeast, cells of, xvi, 142-3;
disease-producing, x, 196;
fermentation in dough, ix, 248;
fermentation by pure and other cultures, x, 138;
leavening powers of, viii, 50;
non-flowering plant, xiii, 13, 14, 43;
origin of power, 71;
reproduction, 164;
vitamines in, ix, 36, x, 260, 261
Yellow, complementary color of, iv, 367;
photographic action of,366;
soothing effects, vi, 274;
wave length of, iv, 359, 365
Yellow Days, cause, i, 57
Yellow Fever, x, 159-63;
campaign against, 162, 172-3, xiv, 356-7;
discovery of cause, x, 160-3, 173, 200;
immunity to, 207, xiv, 357;
virus of, x, 161, 200
Yellow Race, xv, 32;
brain and skull capacity in, 41;
diseases of, 51;
facial angle in, 45;
jaw angle of, 44;
nose index and nostril shape, 46;
peoples of, 37;
separate origin theory, 70;
skull index, 42
Yellowstone Lake, xiv, 180;
altitude, 205

Yellowstone National Park, freaks of nature in, vii, 202;
geysers in, iii, 129;
Hayden Relief model, xiv, 10;
hot springs, 143;
jointed rocks, 129;
petrified forests, iii, 126-7;
travertine terraces, xiv, 146;
uncooled lava masses, 313-14

Yellowstone River, canyon of (see Grand Canyon of the Yellowstone);
falls of, iii, 48-9;
geological history, xiv, 180
Yerkes Telescope, ii, 98, 202;
magnification by, iv, 346
Yersin, bubonic plague work, x, 164, 165;
pupil of Pasteur, 143
Yew Tree, ancestors of, xiii, 317;
a conifer, 174;
in landscaping, 270;
of Tasmania, 30
Yorkshire Coast, recession of, xiv, 47, 301
Yosemite Falls, iii, 47-8, 65
Yosemite Valley, air currents, i, 296, 297;
formation, iii, 44, 64-6, 225;
granite walls, 112, 214;
impressiveness, vii, 202

Young, Prof., astronomical work, ii, 120, 128, 142, 181, 183, 201, 222-3, 307

Young, Thomas, x, 96-7, xvi, 174
Young's Modulus, iv, 157, 158
Yperman, Jean, x, 41
Ypres, chemical warfare at, x, 186
Yssel River, xiv, 45

Ytterbium, symbol and atomic weight, viii, 383

Yttrium, symbol and atomic weight, viii, 383
Yucatan, chocolate cultivation, xiii, 234;
sisal production, 240-1
Yucca Plant, pollination of, xvi, 152-3
Yukon River, use of, xiv, 191
Zambezi, crocodiles of, xii, 200

Zambezi River, gorge and falls of, xiv, 131-2,

(see also Victoria Falls);
lava field of, 317;
varied course, 155
Zanzibar, clove production, xiii, 262, 263
Zebras, xii, 307-8
Zeno, Greek philosopher, xvi, 84-5
Zeolites, in softening water, viii, 324
Zeppelin, Friedrich von, v, 225-6, 228, 382
Zeppelins, v, 225-6, 228-9, 382;
development by Germany, i, 40;
in World War, 310
Zero, invention of, xvi, 184
Ziczac, Egyptian, xii, 263
Zinc, affinity intensity, viii, 128;
atomic weight and symbol, 383;
extraction from ores, 270, 271;
in electric cells, vi, 59, 61, viii, 167;
in heavy metal group, 126-7, 154;
melting point and requirements, iv, 162, viii, 384;
occurrence and production, iii, 363-4, viii, 129, 198;
specific gravity, 384;
test for, 287, 289;
uses, iii, 363, viii, 155-6;
used in hydrogen preparation, 32-3
Zinc Carbonate, viii, 130
Zinc Sulphate, viii, 96
Zircon, iii, 341;
axis ratio, 317

Zirconium, symbol and atomic weight, viii, 383

Zodiac, ii, 254
Zodiacon, i, 192
Zoetrope, v, 329
Zone of Flowage, iii, 84
Zone of Fracture, iii, 84;
action of rocks in, 86

Zones, Climatic, earliest distinction, iii, 220;
not marked in oldest times, 173, 178, 184, 202

Zones of Silence, i, 189-92
Zoögonidia, movements, xvi, 166
Zooids, xii, 34
Zoölogy, Volume xii
Zoölogy, binomial nomenclature in, x, 84;
daily interest, xvi, 15-16, 22, 25-6;
defined, xvi, 36;
history of development, 116, 126, 140-8
Zoöpraxiscope, v, 330
Zorilla, xii, 348
Zuider Zee, formation of present, xiv, 45-6
Zulus, ideas of future life, xv, 333;
musical instruments of, 317;
polygamy among, 288

Zuni Indians, pottery-making by, xv, 250 (fig.)

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Table of Contents

- HOW TO USE THE POPULAR SCIENCE LIBRARY BY GARRETT P. SERVISS HISTORY OF SCIENCE BY ARTHUR SELWYN-BROWN GENERAL INDEX

- PREFACE
- CONTENTS
- LIST OF ILLUSTRATIONS

- HOW TO USE THE POPULAR SCIENCE LIBRARY

- 1—Things on the Earth—Explained by
- 2—Things Above the Earth—Explained by
- 3—Things Within the Earth—Explained by

- CHAPTER I HISTORY OF SCIENCE

- CHAPTER II PRIMITIVE MAN AND EARLY CIVILIZATIONS

- CHAPTER III PRE-BABYLONIAN SCIENCE

- CHAPTER IV EGYPTIAN SCIENCE

- CHAPTER V FOUNDING OF SYSTEMATIC SCIENCE IN GREECE

- CHAPTER VI GOLDEN AGE OF GREEK SCIENCES

- CHAPTER VII THE ROMAN AND MIDDLE AGES

- CHAPTER VIII SCIENCE IN THE SEVENTEENTH CENTURY

- CHAPTER IX PRELUDE TO MODERN SCIENCE—THE EIGHTEENTH CENTURY

- CHAPTER X PHYSICAL SCIENCES IN THE NINETEENTH CENTURY

- CHAPTER XI THE NATURAL SCIENCES

- CHAPTER XII ORGANIC EVOLUTION, VARIATION, AND HEREDITY

- CHAPTER XIII CHEMICAL AND BOTANICAL THEORIES

- CHAPTER XIV GEOLOGY, METALLURGY, AND METEOROLOGY

- CHAPTER XV MEDICINE AND PHARMACY

- CHAPTER XVI ELECTRICITY AND RADIOACTIVITIES

- CHAPTER XVII SCIENCE IN THE TWENTIETH CENTURY

- GENERAL INDEX
- Revision Service Popular Science Library
- TRANSCRIBER'S NOTES
- THE FULL PROJECT GUTENBERG™ LICENSE