How to Use the Popular Science Library; History of Science; General Index
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Title: How to Use the Popular Science Library; History of Science; General Index
Author: Garrett Putman Serviss
Arthur Selwyn-Brown
Release date: February 6, 2016 [eBook #51133]
Most recently updated: October 22, 2024
Language: English
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*** START OF THE PROJECT GUTENBERG EBOOK HOW TO USE THE POPULAR SCIENCE LIBRARY; HISTORY OF SCIENCE; GENERAL INDEX ***
[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 exp
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