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Title: How to Use the Popular Science Library; History of Science; General Index
Author: Serviss, Garrett Putman, Selwyn-Brown, Arthur
Language: English
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Copyright Status: Not copyrighted in the United States. If you live elsewhere check the laws of your country before downloading this ebook. See comments about copyright issues at end of book.

*** Start of this Doctrine Publishing Corporation Digital Book "How to Use the Popular Science Library; History of Science; General Index" ***

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[Illustration:

                                               Copyright, Ewing Galloway]

[Illustration: _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_

                            [Illustration]

                            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

                            [Illustration]

                      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.

[Illustration:

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

THE LITTLE EOHIPPUS. FROM WHICH THE MODERN HORSE DEVELOPED]

[Illustration: ORNITHOLESTES--PREHISTORIC ANIMAL OF AMERICA]

[Illustration:

                                              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.

[Illustration: EXHIBITION OF COPIES OF PREHISTORIC PAINTINGS FROM THE
CAVERNS AT ALTAMIRA, SPAIN]

[Illustration:

  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 = ½gt², 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.

[Illustration: MODELS OF GUTENBERG'S PRINTING PRESSES

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

[Illustration: 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.

[Illustration: ~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.

[Illustration:

                                               Copyright, Ewing Galloway

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

[Illustration: CURTISS NAVY RACER, THE AIRPLANE THAT WON THE PULITZER
RACE OF 1921]

[Illustration: 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.

[Illustration: 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.]

[Illustration: MODEL OF AN EARLY TURNING LATHE

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

[Illustration:

                                        Copyright, Underwood & Underwood

AN EDISON PHONOGRAPH OF 1878

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

[Illustration: 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 x² + y² = 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.

[Illustration: DE WITT CLINTON TRAIN OF 1831 BESIDE A MODERN
LOCOMOTIVE]

[Illustration: LOCOMOTIVE OF THE 1870 PERIOD STILL IN USE IN THE OZARKS]

[Illustration: "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.

[Illustration:

                                            Copyright, Keystone View Co.

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

[Illustration:

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."

[Illustration:

                                            Photo, Fifth Avenue Hospital

ROOM IN WHICH INFECTED ARTICLES ARE STERILIZED]

[Illustration: 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 B₂O for benzoic
acid, B₂CL₂ for chlorbenzol and B₂ + NH₂ 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. C₁₀H₈ being the nucleus of the naphthalene group and C₂H₄ 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.

[Illustration:

                                            Copyright, Keystone View Co.

EDOUARD BELIN AND THE TELAUTOGRAPH, WHICH TRANSMITS PICTURES BY WIRE]

[Illustration: LEE DE FOREST, INVENTOR OF THE OSCILLATING AUDION]

[Illustration: 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.

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

[Illustration: 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]

[Illustration: 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