0379
0379f
An Introduction to the History of Science
AN INTRODUCTION TO THE HISTORY OF SCIENCE
by
WALTER LIBBY, M.A., Ph.D.
Professor of the History of Science
in the Carnegie Institute of Technology
[Illustration]
Boston New York Chicago
Houghton Mifflin Company
The Riverside Press Cambridge
Copyright, 1917, by Walter Libby
All Rights Reserved
The Riverside Press
Cambridge. Massachusetts
U . S . A
TO MY STUDENTS OF THE LAST TWELVE YEARS IN THE CHICAGO AND
PITTSBURGH DISTRICTS THIS BOOK IS INSCRIBED IN FURTHERANCE OF THE
ENDEAVOR TO INCULCATE A DEMOCRATIC CULTURE, EVER MINDFUL OF THE
DAILY TASK, NOT ALTOGETHER IGNORANT OF THE ACHIEVEMENTS OF THE PAST
PREFACE
The history of science has something to offer to the humblest
intelligence. It is a means of imparting a knowledge of scientific facts
and principles to unschooled minds. At the same time it affords a simple
method of school instruction. Those who understand a business or an
institution best, as a contemporary writer on finance remarks, are those
who have made it or grown up with it, and the next best thing is to know
how it has grown up, and then watch or take part in its actual working.
Generally speaking, we know best what we know in its origins.
The history of science is an aid in scientific research. It places the
student in the current of scientific thought, and gives him a clue to
the purpose and necessity of the theories he is required to master. It
presents science as the constant pursuit of truth rather than the
formulation of truth long since revealed; it shows science as
progressive rather than fixed, dynamic rather than static, a growth to
which each may contribute. It does not paralyze the self-activity of
youth by the record of an infallible past.
It is only by teaching the sciences in their historical development that
the schools can be true to the two principles of modern education, that
the sciences should occupy the foremost place in the curriculum and that
the individual mind in its evolution should rehearse the history of
civilization.
The history of science should be given a larger place than at present in
general history; for, as Bacon said, the history of the world without a
history of learning is like a statue of Polyphemus with the eye out. The
history of science studies the past for the sake of the future. It is a
story of continuous progress. It is rich in biographical material. It
shows the sciences in their interrelations, and saves the student from
narrowness and premature specialization. It affords a unique approach to
the study of philosophy. It gives new motive to the study of foreign
languages. It gives an interest in the applications of knowledge, offers
a clue to the complex civilization of the present, and renders the mind
hospitable to new discoveries and inventions.
The history of science is hostile to the spirit of caste. It shows the
sciences rising from daily needs and occupations, formulated by
philosophy, enriching philosophy, giving rise to new industries, which
react in turn upon the sciences. The history of science reveals men of
all grades of intelligence and of all social ranks coöperating in the
cause of human progress. It is a basis of intellectual and social
homogeneity.
Science is international, English, Germans, French, Italians,
Russians--all nations--contributing to advance the general interests.
Accordingly, a survey of the sciences tends to increase mutual respect,
and to heighten the humanitarian sentiment. The history of science can
be taught to people of all creeds and colors, and cannot fail to enhance
in the breast of every young man, or woman, faith in human progress and
good-will to all mankind.
This book is intended as a simple introduction, taking advantage of the
interests of youth of from seventeen to twenty-two years of age (and
their intellectual compeers) in order to direct their attention to the
story of the development of the sciences. It makes no claim to be in any
sense complete or comprehensive. It is, therefore, a psychological
introduction, having the mental capacity of a certain class of readers
always in view, rather than a logical introduction, which would
presuppose in all readers both full maturity of intellect and
considerable initial interest in the history of science.
I cannot conclude this preface without thanking those who have assisted
me in the preparation of this book--Sir William Osler, who read the
first draft of the manuscript, and aided me with his counsel; Dr.
Charles Singer, who read all the chapters in manuscript, and to whom I
am indebted for advice in reference to the illustrations and for many
other valuable suggestions; the officers of the Bodleian Library, whose
courtesy was unfailing during the year I worked there; Professor Henry
Crew, who helped in the revision of two of the chapters by his judicious
criticism; Professor J. E. Rush, whose knowledge of bacteriology
improved the chapter on Pasteur; Professor L. O. Grondahl, who read one
of the chapters relating to the history of physics and suggested
important emendations; and Dr. John A. Brashear, who contributed
valuable information in reference to the activities of Samuel Pierpont
Langley. I wish to express my gratitude also to Miss Florence Bonnet for
aid in the correction of the manuscript.
W. LIBBY.
February 2, 1917.
CONTENTS
I. SCIENCE AND PRACTICAL NEEDS--EGYPT AND BABYLONIA 1
II. THE INFLUENCE OF ABSTRACT THOUGHT--GREECE: ARISTOTLE 15
III. SCIENTIFIC THEORY SUBORDINATED TO APPLICATION--ROME:
VITRUVIUS 30
IV. THE CONTINUITY OF SCIENCE--THE MEDIEVAL CHURCH AND
THE ARABS 43
V. THE CLASSIFICATION OF THE SCIENCES--FRANCIS BACON 57
VI. SCIENTIFIC METHOD--GILBERT, GALILEO, HARVEY, DESCARTES 72
VII. SCIENCE AS MEASUREMENT--TYCHO BRAHE, KEPLER, BOYLE 86
VIII. COÖPERATION IN SCIENCE--THE ROYAL SOCIETY 99
IX. SCIENCE AND THE STRUGGLE FOR LIBERTY--BENJAMIN FRANKLIN 114
X. THE INTERACTION OF THE SCIENCES--WERNER, HUTTON, BLACK,
HALL, WILLIAM SMITH 129
XI. SCIENCE AND RELIGION--KANT, LAMBERT, LAPLACE, SIR
WILLIAM HERSCHEL 142
XII. THE REIGN OF LAW--DALTON, JOULE 155
XIII. THE SCIENTIST--SIR HUMPHRY DAVY 170
XIV. SCIENTIFIC PREDICTION--THE DISCOVERY OF NEPTUNE 184
XV. SCIENCE AND TRAVEL--THE VOYAGE OF THE BEAGLE 197
XVI. SCIENCE AND WAR--PASTEUR, LISTER 213
XVII. SCIENCE AND INVENTION--LANGLEY'S AEROPLANE 231
XVIII. SCIENTIFIC HYPOTHESIS--RADIOACTIVE SUBSTANCES 245
XIX. THE SCIENTIFIC IMAGINATION 258
XX. SCIENCE AND DEMOCRATIC CULTURE 270
INDEX 283
ILLUSTRATIONS
EARLIEST PICTURE KNOWN OF A SURGICAL OPERATION.
EGYPT, 2500 B.C. 6
ST. THOMAS AQUINAS OVERCOMING AVERROËS 54
DR. GILBERT SHOWING HIS ELECTRICAL EXPERIMENTS
TO QUEEN ELIZABETH AND HER COURT 72
THE TICHONIC QUADRANT 88
WADHAM COLLEGE, OXFORD 104
SIR ISAAC NEWTON 112
JOHN DALTON COLLECTING MARSH GAS 162
THE FIRST SUCCESSFUL HEAVIER-THAN-AIR FLYING MACHINE 236
AN INTRODUCTION TO THE HISTORY OF SCIENCE
CHAPTER I
SCIENCE AND PRACTICAL NEEDS--EGYPT AND BABYLONIA
If you consult encyclopedias and special works in reference to the early
history of any one of the sciences,--astronomy, geology, geometry,
physiology, logic, or political science, for example,--you will find
strongly emphasized the part played by the Greeks in the development of
organized knowledge. Great, indeed, as we shall see in the next chapter,
are the contributions to the growth of science of this highly rational
and speculative people. It must be conceded, also, that the influence on
Western science of civilizations earlier than theirs has come to us, to
a considerable extent at least, through the channels of Greek
literature.
Nevertheless, if you seek the very origins of the sciences, you will
inevitably be drawn to the banks of the Nile, and to the valleys of the
Tigris and the Euphrates. Here, in Egypt, in Assyria and Babylonia,
dwelt from very remote times nations whose genius was practical and
religious rather than intellectual and theoretical, and whose mental
life, therefore, was more akin to our own than was the highly evolved
culture of the Greeks. Though more remote in time, the wisdom and
practical knowledge of Thebes and Memphis, Nineveh and Babylon, are more
readily comprehended by our minds than the difficult speculations of
Athenian philosophy.
Much that we have inherited from the earliest civilizations is so
familiar, so homely, that we simply accept it, much as we may light, or
air, or water, without analysis, without inquiry as to its origin, and
without full recognition of how indispensable it is. Why are there seven
days in the week, and not eight? Why are there sixty minutes in the
hour, and why are there not sixty hours in the day? These artificial
divisions of time are accepted so unquestioningly that to ask a reason
for them may, to an indolent mind, seem almost absurd. This acceptance
of a week of seven days and of an hour of sixty minutes (almost as if
they were natural divisions of time like day and night) is owing to a
tradition that is Babylonian in its origin. From the Old Testament
(which is one of the greatest factors in preserving the continuity of
human culture, and the only ancient book which speaks with authority
concerning Babylonian history) we learn that Abraham, the progenitor of
the Hebrews, migrated to the west from southern Babylonia about
twenty-three hundred years before Christ. Even in that remote age,
however, the Babylonians had established those divisions of time which
are familiar to us. The seven days of the week were closely associated
in men's thinking with the heavenly bodies. In our modern languages they
are named after the sun, the moon, Mars, Mercury, Jupiter, Venus, and
Saturn, which from the remotest times were personified and worshiped.
Thus we see that the usage of making seven days a unit of time depends
on the religious belief and astronomical science of a very remote
civilization. The usage is so completely established that by the
majority it is simply taken for granted.
Another piece of commonplace knowledge--the cardinal points of the
compass--may be accepted, likewise, without inquiry or without
recognition of its importance. Unless thrown on your own resources in an
unsettled country or on unknown waters, you may long fail to realize how
indispensable to the practical conduct of life is the knowledge of east
and west and north and south. In this matter, again, the records of
ancient civilizations show the pains that were taken to fix these
essentials of science. Modern excavations have demonstrated that the
sides or the corners of the temples and palaces of Assyria and Babylonia
were directed to the four cardinal points of the compass. In Egypt the
pyramids, erected before 3000 B.C., were laid out with such strict
regard to direction that the conjecture has been put forward that their
main purpose was to establish, in a land of shifting sands, east and
west and north and south. That conjecture seems extravagant; but the
fact that the Phœnicians studied astronomy merely because of its
practical value in navigation, the early invention of the compass in
China, the influence on discovery of the later improvements of the
compass, make us realize the importance of the alleged purpose of the
pyramids. Without fixed points, without something to go by, men, before
they had acquired the elements of astronomy, were altogether at sea. As
they advanced in knowledge they looked to the stars for guidance,
especially to the pole star and the imperishable star-group of the
northern heavens. The Egyptians even developed an apparatus for telling
the time by reference to the stars--a star-clock similar in its purpose
to the sundial. By the Egyptians, also, was carefully observed the
season of the year at which certain stars and constellations were
visible at dawn. This was of special importance in the case of Sirius,
for its heliacal rising, that is, the period when it rose in conjunction
with the sun, marked the coming of the Nile flood (so important in the
lives of the inhabitants) and the beginning of a new year. Not
unnaturally Sirius was an object of worship. One temple is said to have
been so constructed as to face that part of the eastern horizon at which
this star arose at the critical season of inundation. Of another temple
we are told that only at sunset at the time of the summer solstice did
the sun throw its rays throughout the edifice. The fact that astronomy
in Egypt as in Babylonia, where the temples were observatories, was
closely associated with religion confirms the view that this science was
first cultivated because of its bearing on the practical needs of the
people. The priests were the preservers of such wisdom as had been
accumulated in the course of man's immemorial struggle with the forces
of nature.
It is well known that geometry had its origin in the valley of the Nile,
that it arose to meet a practical need, and that it was in the first
place, as its name implies, a measurement of the earth--a crude
surveying, employed in the restoration of boundaries obliterated by the
annual inundations of the river. Egyptian geometry cared little for
theory. It addressed itself to actual problems, such as determining the
area of a square or triangular field from the length of the sides. To
find the area of a circular field, or floor, or vessel, from the length
of the diameter was rather beyond the science of 2000 B.C. This was,
however, a practical problem which had to be solved, even if the
solution were not perfect. The practice was to square the diameter
reduced by one ninth.
In all the Egyptian mathematics of which we have record there is to be
observed a similar practical bent. In the construction of a temple or a
pyramid not merely was it necessary to have regard to the points of the
compass, but care must be taken to have the sides at right angles. This
required the intervention of specialists, expert "rope-fasteners," who
laid off a triangle by means of a rope divided into three parts, of
three, four, and five units. The Babylonians followed much the same
practice in fixing a right angle. In addition they learned how to bisect
and trisect the angle. Hence we see in their designs and ornaments the
division of the circle into twelve parts, a division which does not
appear in Egyptian ornamentation till after the incursion of Babylonian
influence.
There is no need, however, to multiply examples; the tendency of all
Egyptian mathematics was, as already stated, concerned with the
practical solution of concrete problems--mensuration, the cubical
contents of barns and granaries, the distribution of bread, the amounts
of food required by men and animals in given numbers and for given
periods of time, the proportions and the angle of elevation (about 52°)
of a pyramid, etc. Moreover, they worked simple equations involving one
unknown, and had a hieroglyph for a million (the drawing of a man
overcome with wonder), and another for ten million.
The Rhind mathematical papyrus in the British Museum is the main source
of our present knowledge of early Egyptian arithmetic, geometry, and of
what might be called their trigonometry and algebra. It describes itself
as "Instructions for arriving at the knowledge of all things, and of
things obscure, and of all mysteries." It was copied by a priest about
1600 B.C.--the classical period of Egyptian culture--from a document
seven hundred years older.
[Illustration: EARLIEST PICTURE KNOWN OF A SURGICAL OPERATION. EGYPT,
2500 B.C.]
Medicine, which is almost certain to develop in the early history of a
people in response to their urgent needs, has been justly called the
foster-mother of many sciences. In the records of Egyptian medical
practice can be traced the origin of chemistry, anatomy, physiology, and
botany. Our most definite information concerning Egyptian medicine
belongs to the same general period as the mathematical document to which
we have just referred. It is true something is known of remoter times.
The first physician of whom history has preserved the name, I-em-hetep
(He-who-cometh-in-peace), lived about 4500 B.C. Recent researches have
also brought to light, near Memphis, pictures, not later than 2500 B.C.,
of surgical operations. They were found sculptured on the doorposts at
the entrance to the tomb of a high official of one of the Pharaohs. The
patients, as shown in the accompanying illustration, are suffering pain,
and, according to the inscription, one cries out, "Do this [and] let me
go," and the other, "Don't hurt me so!" Our most satisfactory data in
reference to Egyptian medicine are derived, however, from the Ebers
papyrus. This document displays some little knowledge of the pulse in
different parts of the body, of a relation between the heart and the
other organs, and of the passage of the breath to the lungs (and heart).
It contains a list of diseases. In the main it is a collection of
prescriptions for the eyes, ears, stomach, to reduce tumors, effect
purgation, etc. There is no evidence of a tendency to homeopathy, but
mental healing seems to have been called into play by the use of
numerous spells and incantations. Each prescription, as in medical
practice to-day, contains as a rule several ingredients. Among the seven
hundred recognized remedies are to be noted poppy, castor-oil, gentian,
colchicum, squills, and many other familiar medicinal plants, as well as
bicarbonate of soda, antimony, and salts of lead and copper. The fat of
the lion, hippopotamus, crocodile, goose, serpent, and wild goat, in
equal parts, served as a prescription for baldness. In the interests of
his art the medical practitioner ransacked the resources of organic and
inorganic nature. The Ebers papyrus shows that the Egyptians knew of the
development of the beetle from the egg, of the blow-fly from the larva,
and of the frog from the tadpole. Moreover, for precision in the use of
medicaments weights of very small denominations were employed.
The Egyptian embalmers relied on the preservative properties of common
salt, wine, aromatics, myrrh, cassia, etc. By the use of linen smeared
with gum they excluded all putrefactive agencies. They understood the
virtue of extreme dryness in the exercise of their antiseptic art. Some
knowledge of anatomy was involved in the removal of the viscera, and
much more in a particular method they followed in removing the brain.
In their various industries the Egyptians made use of gold, silver,
bronze (which on analysis is found to consist of copper, tin, and a
trace of lead, etc.), metallic iron and copper and their oxides,
manganese, cobalt, alum, cinnabar, indigo, madder, brass, white lead,
lampblack. There is clear evidence that they smelted iron ore as early
as 3400 B.C. maintaining a blast by means of leather tread-bellows. They
also contrived to temper the metal, and to make helmets, swords,
lance-points, ploughs, tools, and other implements of iron. Besides
metallurgy they practiced the arts of weaving, dyeing, distillation.
They produced soap (from soda and oil), transparent and colored glass,
enamel, and ceramics. They were skilled in the preparation of leather.
They showed aptitude for painting, and for the other fine arts. They
were expert builders, and possessed the engineering skill to erect
obelisks weighing hundreds of tons. They cultivated numerous vegetables,
grains, fruits, and flowers. They had many domestic animals. In seeking
the satisfaction of their practical needs they laid the foundation of
geometry, botany, chemistry (named, as some think, from the Egyptian
Khem, the god of medicinal herbs), and other sciences. But their
practical achievements far transcended their theoretical formulations.
To all time they will be known as an artistic, noble, and religious
people, who cherished their dead and would not allow that the good and
beautiful and great should altogether pass away.
Excavations in Assyria and Babylonia, especially since 1843, have
brought to our knowledge an ancient culture stretching back four or five
thousand years before the beginning of the Christian era. The records of
Assyria and Babylonia, like those of Egypt, are fragmentary and still in
need of interpretation. Here again, however, it is the fundamental, the
indispensable, the practical forms of knowledge that stand revealed
rather than the theoretical, speculative, and purely intellectual.
By the Babylonian priests the heavens were made the object of expert
observation as early as 3800 B.C. The length of the year, the length of
the month, the coming of the seasons, the course of the sun in the
heavens, the movements of the planets, the recurrence of eclipses,
comets, and meteors, were studied with particular care. One motive was
the need of a measurement of time, the same motive as underlies the
common interest in the calendar and almanac. It was found that the year
contained more than 365 days, the month (synodic) more than 29 days, 12
hours, and 44 minutes. The sun's apparent diameter was contained 720
times in the ecliptic, that is, in the apparent path of the sun through
the heavens. Like the Egyptians, the Babylonians took special note of
the stars and star-groups that were to be seen at dawn at different
times of the year. These constellations, lying in the imaginary
belt encircling the heavens on either side of the ecliptic, bore
names corresponding to those we have adopted for the signs of the
zodiac,--Balance, Ram, Bull, Twins, Scorpion, Archer, etc. The
Babylonian astronomers also observed that the successive vernal (or
autumnal) equinoxes follow each other at intervals of a few seconds
less than a year.
A second motive that influenced the Babylonian priests in studying the
movements of the heavenly bodies was the hope of foretelling events. The
planets, seen to shift their positions with reference to the other
heavenly bodies, were called messengers, or angels. The appearance of
Mars, perhaps on account of its reddish color, was associated in their
imaginations with war. Comets, meteors, and eclipses were considered as
omens portending pestilence, national disaster, or the fate of kings.
The fortunes of individuals could be predicted from a knowledge of the
aspect of the heavens at the hour of their birth. This interest in
astrology, or divination by means of the stars, no doubt stimulated the
priests to make careful observations and to preserve religiously the
record of astronomical phenomena. It was even established that there is
a cycle in which eclipses, solar and lunar, repeat themselves, a period
(_saros_) somewhat more than eighteen years and eleven months. Moreover,
from the Babylonians we derive some of our most sublime religious and
scientific conceptions. They held that strict law governs the apparently
erratic movements of the heavenly bodies. Their creation myth proclaims:
"Merodach next arranged the stars in order, along with the sun and moon,
and gave them laws which they were never to transgress."
The mathematical knowledge of the Babylonians is related on the one hand
to their astronomy and on the other to their commercial pursuits. They
possessed highly developed systems of measuring, weighing, and
counting--processes, which, as we shall see in the sequel, are essential
to scientific thought. About 2300 B.C. they had multiplication tables
running from 1 to 1350, which were probably used in connection with
astronomical calculations. Unlike the Egyptians they had no symbol for a
million, though the "ten thousand times ten thousand" of the Bible
(Daniel VII: 10) may indicate that the conception of even larger numbers
was not altogether foreign to them. They counted in sixties as well as
in tens. Their hours and minutes had each sixty subdivisions. They
divided the circle into six parts and into six-times-sixty subdivisions.
Tables of squares and cubes discovered in southern Babylonia were
interpreted correctly only on a sexagesimal basis, the statement that 1
plus 4 is the square of 8 implying that the first unit is 60. As we have
already seen, considerable knowledge of geometry is apparent in
Babylonian designs and constructions.
According to a Greek historian of the fifth century B.C., there were no
physicians at Babylon, while a later Greek historian (of the first
century B.C.) speaks of a Babylonian university which had attained
celebrity, and which is now believed to have been a school of medicine.
Modern research has made known letters by a physician addressed to an
Assyrian king in the seventh century B.C. referring to the king's chief
physician, giving directions for the treatment of a bleeding from the
nose from which a friend of the prince was suffering, and reporting the
probable recovery of a poor fellow whose eyes were diseased. Other
letters from the same general period mention the presence of physicians
at court. We have even recovered the name (Ilu-bani) of a physician who
lived in southern Babylonia about 2700 B.C. The most interesting
information, however, in reference to Babylonian medicine dates from the
time of Hammurabi, a contemporary of the patriarch Abraham. It appears
from the code drawn up in the reign of that monarch that the Babylonian
surgeons operated in case of cataract; that they were entitled to twenty
silver shekels (half the sum for which Joseph was sold into slavery, and
equivalent to seven or eight dollars) for a successful operation; and
that in case the patient lost his life or his sight as the result of an
unsuccessful operation, the surgeon was condemned to have his hands
amputated.
The Babylonian records of medicine like those of astronomy reveal the
prevalence of many superstitious beliefs. The spirits of evil bring
maladies upon us; the gods heal the diseases that afflict us. The
Babylonian books of medicine contained strange interminglings of
prescription and incantation. The priests studied the livers of
sacrificial animals in order to divine the thoughts of the gods--a
practice which stimulated the study of anatomy. The maintenance of state
menageries no doubt had a similar influence on the study of the natural
history of animals.
The Babylonians were a nation of agriculturists and merchants. Sargon of
Akkad, who founded the first Semitic empire in Asia (3800 B.C.), was
brought up by an irrigator, and was himself a gardener. Belshazzar, the
son of the last Babylonian king, dealt in wool on a considerable scale.
Excavation in the land watered by the Tigris and Euphrates tells the
tale of the money-lenders, importers, dyers, fullers, tanners,
saddlers, smiths, carpenters, shoemakers, stonecutters, ivory-cutters,
brickmakers, porcelain-makers, potters, vintners, sailors, butchers,
engineers, architects, painters, sculptors, musicians, dealers in rugs,
clothing and fabrics, who contributed to the culture of this great
historic people. It is not surprising that science should find its
matrix in so rich a civilization.
The lever and the pulley, lathes, picks, saws, hammers, bronze
operating-lances, sundials, water-clocks, the gnomon (a vertical pillar
for determining the sun's altitude) were in use. Gem-cutting was highly
developed as early as 3800 B.C. The Babylonians made use of copper
hardened with antimony and tin, lead, incised shells, glass, alabaster,
lapis-lazuli, silver, and gold. Iron was not employed before the period
of contact with Egyptian civilization. Their buildings were furnished
with systems of drains and flushes that seem to us altogether modern.
Our museums are enriched by specimens of their handicraft--realistic
statuary in dolerite of 2700 B.C.; rock crystal worked to the form of a
plano-convex lens, 3800 B.C.; a beautiful silver vase of the period 3950
B.C.; and the head of a goat in copper about 4000 B.C.
Excavation has not disclosed nor scholarship interpreted the full record
of this ancient people in the valley of the Tigris and the Euphrates,
not far from the Gulf of Persia, superior in religious inspiration, not
inferior in practical achievements to the Egyptians. Both these great
nations of antiquity, however, failed to carry the sciences that arose
in connection with their arts to a high degree of generalization. That
was reserved for another people of ancient times, namely, the Greeks.
REFERENCES
F. H. Garrison, _An Introduction to the History of Medicine_.
H. V. Hilprecht, _Excavations in Assyria and Babylonia_.
Max Neuburger, _History of Medicine_.
A. H. Sayce, _Babylonians and Assyrians_.
CHAPTER II
THE INFLUENCE OF ABSTRACT THOUGHT--GREECE: ARISTOTLE
No sooner did the Greeks turn their attention to the sciences which had
originated in Egypt and Babylonia than the characteristic intellectual
quality of the Hellenic genius revealed itself. Thales (640-546 B.C.),
who is usually regarded as the first of the Greek philosophers, was the
founder of Greek geometry and astronomy. He was one of the seven "wise
men" of Greece, and might be called the Benjamin Franklin of antiquity,
for he was interested in commerce, famous for political sagacity, and
honored for his disinterested love of general truth. His birthplace was
Miletus, a Greek city on the coast of Asia Minor. There is evidence that
he acquired a knowledge of Babylonian astronomy. The pursuit of commerce
carried him to Egypt, and there he gained a knowledge of geometry. Not
only so, but he was able to advance this study by generalizing and
formulating its truths. For the Egyptians, geometry was concerned with
surfaces and dimensions, with areas and cubical contents; for the Greek,
with his powers of abstraction, it became a study of line and angle. For
example, Thales saw that the angles at the base of an isosceles triangle
are equal, and that when two straight lines cut one another the
vertically opposite angles are equal. However, after having established
general principles, he showed himself capable of applying them to the
solution of particular problems. In the presence of the Egyptian
priests, to which class he was solely indebted for instruction, Thales
demonstrated a method of measuring the height of a pyramid by reference
to its shadow. And again, on the basis of his knowledge of the relation
of the sides of a triangle to its angles, he developed a practical rule
for ascertaining the distance of a ship from the shore.
The philosophical mind of Thales laid hold, no doubt, of some of the
essentials of astronomical science. The particulars usually brought
forward to prove his originality tend rather to show his indebtedness to
the Babylonians. The number of days in the year, the length of the
synodic month, the relation of the sun's apparent diameter to the
ecliptic, the times of recurrence of eclipses, were matters that had
long been known to the Babylonians, as well as to the Chinese. However,
he aroused great interest in astronomy among the Greeks by the
prediction of a solar eclipse. This was probably the eclipse of 585
B.C., which interrupted a fierce battle between the Medes and the
Lydians. The advice of Thales to mariners to steer by the Lesser Bear,
as nearer the pole, rather than by the Great Bear, shows also that in
his astronomical studies as in his geometrical he was not indifferent to
the applications of scientific knowledge.
In fact, some writers maintain that Thales was not a philosopher at all,
but rather an astronomer and engineer. We know very little of his purely
speculative thought. We do know, however, that he arrived at a
generalization--fantastic to most minds--that all things are water.
Attempts have been made to add to this statement, and to explain it
away. Its great interest for the history of thought lies in the fact
that it is the result of seeking the constant in the variable, the
unitary principle in the multiple phenomena of nature. This abstract and
general view (though perhaps suggested by the Babylonian belief that the
world originated in a watery chaos, or by the teaching of Egyptian
priests) was preëminently Greek, and was the first of a series of
attempts to discover the basis or origin of all things. One of the
followers of Thales taught that air was the fundamental principle; while
Heraclitus, anticipating to some extent modern theories of the origin of
the cosmos, declared in favor of a fiery vapor subject to ceaseless
change. Empedocles, the great philosopher-physician, first set forth the
doctrine of the four _elements_--earth, air, fire, and water. For
Democritus indivisible particles or atoms are fundamental to all
phenomena. It is evident that the theory of Thales was a starting point
for Greek abstract thought, and that his inclination to seek out
principles and general laws accounts for his influence on the
development both of philosophy and the sciences.
Pythagoras, on the advice of Thales, visited Egypt in the pursuit of
mathematics. There is reason to believe that he also visited Babylonia.
For him and his followers mathematics became a philosophy--almost a
religion. They had discovered (by experimenting with the monochord, the
first piece of physical-laboratory apparatus, consisting of a tense
harpstring with a movable bridge) the effect on the tone of the string
of a musical instrument when the length is reduced by one half, and also
that strings of like thickness and under equal tension yield harmonious
tones when their lengths are related as 1:2, 2:3, 3:4, 4:5. The
Pythagoreans drew from this the extravagant inference that the heavenly
bodies would be in distance from the earth as 1, 2, 3, 4, 5, etc. Much
of their theory must seem to the modern mind merely fanciful and
unsupported speculation. At the same time it is only just to this school
of philosophers to recognize that their assumption that simple
mathematical relationships govern the phenomena of nature has had an
immense influence on the advance of the sciences. Whether their
fanaticism for number was owing to the influence of Egyptian priests or
had an Oriental origin, it gave to the Pythagoreans an enthusiasm for
pure mathematics. They disregarded the bearing of their science on the
practical needs of life. Old problems like squaring the circle,
trisecting the angle, and doubling the cube, were now attempted in a new
spirit and with fresh vigor. The first, second, and fourth books of
Euclid are largely of Pythagorean origin. For solid geometry as a
science we are also indebted to this sect of number-worshipers. One of
them (Archytas, 428-347 B.C., a friend of Plato) was the first to apply
geometry to mechanics. We see again here, as in the case of Thales, that
the love of abstract thought, the pursuit of science as science, did not
interfere with ultimate practical applications.
Plato (429-347 B.C.), like many other Greek philosophers, traveled
extensively, visiting Asia Minor, Egypt, and Lower Italy, where
Pythagorean influence was particularly strong. His chief interest lay in
speculation. For him there were two worlds, the world of sense and the
world of ideas. The senses deceive us; therefore, the philosopher should
turn his back upon the world of sensible impressions, and develop the
reason. In his _Dialogues_ he outlined a course of training and study,
the professed object of which was to educate a class of philosophers.
(Strange to say, Plato's curriculum, planned originally for the
intellectual _élite_, still dictates in our schools the education of
millions of boys and girls whose careers do not call for a training
merely of the reason.)
Over the porch of his school, the Academy at Athens, were inscribed the
words, "Let no one who is unacquainted with geometry enter here." It was
not because it was useful in everyday life that Plato laid such
insistence on this study, but because it increased the students' powers
of abstraction and trained the mind to correct and vigorous thinking.
From his point of view the chief good of geometry is lost unless we can
through it withdraw the mind from the particular and the material. He
delighted in clearness of conception. His main scientific interest was
in astronomy and mathematics. We owe to him the definition of a line as
"length without breadth," and the formulation of the axiom, "Equals
subtracted from equals leave equals."
Plato had an immediate influence in stimulating mathematical studies,
and has been called a maker of mathematicians. Euclid, who was active at
Alexandria toward the end of the fourth century B.C., was not one of
Plato's immediate disciples but shared the great philosopher's point of
view. The story is told that one of his pupils, arrived perhaps at the
_pons asinorum_, asked, "What do I get by learning these things?"
Euclid, calling his servant, said, "Give him sixpence, since he must
make gain out of what he learns." Adults were also found, even among the
nimble-witted Greeks, to whom abstract reasoning was not altogether
congenial. This is attested by the familiar story of Ptolemy, King of
Egypt, who once asked Euclid whether geometry could not be learned in
some easier way than by studying the geometer's book, _The Elements_. To
this the schoolmaster replied, "There is no royal road to geometry." For
the academic intelligence abstract and abstruse mathematics are tonic
and an end in themselves. As already stated, their ultimate practical
value is also immense. One of Plato's associates, working under his
direction, investigated the curves produced by cutting cones of
different kinds in a certain plane. These curves--the ellipse, the
parabola, the hyperbola--play a large part in the subsequent history of
astronomy and mechanics. Another Platonist made the first measurement of
the earth's circumference.
Aristotle, the greatest pupil of Plato, was born at Stagira in 384 B.C.
He came of a family of physicians, was trained for the medical
profession, and had his attention early directed to natural phenomena.
He entered the Academy at Athens about 367 B.C., and studied there till
the death of Plato twenty years later. He was a diligent but, as was
natural, considering the character of his early education, by no means a
passive student. Plato said that Aristotle reacted against his
instructor as a vigorous colt kicks the mother that nourishes it. The
physician's son did not accept without modification the view that the
philosopher should turn his back upon the things of sense. He had been
trained in the physical science of the time, and believed in the reality
of concrete things. At the same time he absorbed what he found of value
in his master's teachings. He thought that science did not consist in a
mere study of individual things, but that we must pass on to a
formulation of general principles and then return to a study of the
concrete. His was a great systematizing intellect, which has left its
imprint on nearly every department of knowledge. Physical astronomy,
physical geography, meteorology, physics, chemistry, geology, botany,
anatomy, physiology, embryology, and zoölogy were enriched by his
teaching. It was through him that logic, ethics, psychology, rhetoric,
æsthetics, political science, zoölogy (especially ichthyology), first
received systematic treatment. As a great modern philosopher has said,
Aristotle pressed his way through the mass of things knowable, and
subjected its diversity to the power of his thought. No wonder that for
ages he was known as "The Philosopher," master of those who know. His
purpose was to comprehend, to define, to classify the phenomena of
organic and inorganic nature, to systematize the knowledge of his own
time.
Twenty years' apprenticeship in the school of Plato had sharpened his
logical powers and added to his stock of general ideas, but had not
taught him to distrust his senses. When we say that our eyes deceive us,
we really confess that we have misinterpreted the data that our sight
has furnished. Properly to know involves the right use of the senses as
well as the right use of reason. The advance of science depends on the
development both of speculation and observation. Aristotle advised
investigators to make sure of the facts before seeking the explanation
of the facts. Where preconceived theory was at variance with observed
facts, the former must of course give way. Though it has been said that
while Plato was a dreamer, Aristotle was a thinker, yet it must be
acknowledged in qualification that Plato often showed genuine knowledge
of natural phenomena in anatomy and other departments of study, and that
Aristotle was carried away at times by his own presuppositions, or
failed to bring his theories to the test of observation. The Stagirite
held that the velocity of falling bodies is proportional to their
weight, that the function of the diaphragm is to divide the region of
the nobler from that of the animal passions, and that the brain is
intended to act in opposition to the heart, the brain being formed of
earthy and watery material, which brings about a cooling effect. The
theory of the four elements--the hot, the cold, the moist, the dry--led
to dogmatic statements with little attempt at verification. From the
standpoint of modern studies it is easy to point out the mistakes of
Aristotle even. Science is progressive, not infallible.
In his own time he was rather reproached for what was considered an
undignified and sordid familiarity with observed facts. His critics said
that having squandered his patrimony, he had served in the army, and,
failing there, had become a _seller of drugs_. His observations on the
effects of heat seem to have been drawn from the common processes of the
home and the workshop. Even in the ripening of fruits heat appears to
him to have a cooking effect. Heat distorts articles made of potters'
clay after they have been hardened by cold. Again we find him describing
the manufacture of potash and of steel. He is not disdainful of the
study of the lower animals, but invites us to investigate all forms in
the expectancy of discovering something natural and beautiful. In a
similar spirit of scientific curiosity the Aristotelian work _The
Problems_ studies the principle of the lever, the rudder, the wheel and
axle, the forceps, the balance, the beam, the wedge, as well as other
mechanical principles.
In Aristotle, in fact, we find a mind exceptionally able to form clear
ideas, and at the same time to observe the rich variety of nature. He
paid homage both to the multiplicity and the uniformity of nature, the
wealth of the phenomena and the simplicity of the law explaining the
phenomena. Many general and abstract ideas (category, energy,
entomology, essence, mean between extremes, metaphysics, meteorology,
motive, natural history, principle, syllogism) have through the
influence of Aristotle become the common property of educated people the
world over.
Plato was a mathematician and an astronomer. Aristotle was first and
foremost a biologist. His books treated the history of animals, the
parts of animals, the locomotion of animals, the generation of animals,
respiration, life and death, length and shortness of life, youth and old
age. His psychology is, like that of the present day, a biological
psychology. In his contributions to biological science is manifested
his characteristic inclination to be at once abstract and concrete. His
works display a knowledge of over five hundred living forms. He
dissected specimens of fifty different species of animals. One might
mention especially his minute knowledge of the sea-urchin, of the murex
(source of the famous Tyrian dye), of the chameleon, of the habits of
the torpedo, the so-called fishing-frog, and nest-making fishes, as well
as of the manner of reproduction of whales and certain species of
sharks. One of his chief contributions to anatomy is the description of
the heart and of the arrangement of the blood-vessels. A repugnance to
the dissection of the human body seems to have checked to some extent
his curiosity in reference to the anatomy of man, but he was acquainted
with the structure of the internal ear, the passage leading from the
pharynx to the middle ear, and the two outer membranes of the brain of
man. Aristotle's genius did not permit him to get lost in the mere
details of observed phenomena. He recognized resemblances and
differences between the various species, classified animals as belonging
to two large groups, distinguished whales and dolphins from fishes,
recognized the family likeness of the domestic pigeon, the wood pigeon,
the rock pigeon, and the turtle dove. He laid down the characteristics
of the class of invertebrates to which octopus and sepia belong. Man
takes a place in Aristotle's system of nature as a social animal, the
highest type of the whole series of living beings, characterized by
certain powers of recall, reason, deliberation. Of course it was not to
be expected that Aristotle should work out a fully satisfactory
classification of all the varieties of plants and animals known to him.
Yet his purpose and method mark him as the father of natural science. He
had the eye to observe and the mind to grasp the relationships and the
import of what he observed. His attempt to classify animals according to
the nature of their teeth (dentition) has been criticized as
unsuccessful, but this principle of classification is still of use,
and may be regarded as typical of his mind, at once careful and
comprehensive.
One instance of Aristotle's combining philosophical speculation with
acute observation of natural phenomena is afforded by his work on
generation and development. He knew that the transmission of life
deserves special study as the predominant function of the various
species of plants and animals. Deformed parents may have well-formed
offspring. Children may resemble grandparents rather than parents. It is
only toward the close of its development that the embryo exhibits the
characteristics of its parent species. Aristotle traced with some care
the embryological development of the chick from the fourth day of
incubation. His knowledge of the propagation of animals was, however,
not sufficient to make him reject the belief in spontaneous generation
from mud, sand, foam, and dew. His errors are readily comprehensible,
as, for example, in attributing spontaneous generation to eels, the
habits and mode of reproduction of which only recent studies have made
fully known. In regard to generation, as in other scientific fields, the
philosophic mind of Aristotle anticipated modern theories, and also
raised general questions only to be solved by later investigation of the
facts.
Only one indication need be given of the practical results that flowed
from Aristotle's scientific work. In one of his writings he has stated
that the sphericity of the earth can be observed from the fact that its
shadow on the moon at the time of eclipse is an arc. That it is both
spherical and small in comparison with the heavenly bodies appears,
moreover, from this, that stars visible in Egypt are invisible in
countries farther north; while stars always above the horizon in
northern countries are seen to set from countries to the south.
Consequently the earth is not only spherical but also not large;
otherwise this phenomenon would not present itself on so limited a
change of position on the part of the observer. "It seems, therefore,
not incredible that the region about the Pillars of Hercules [Gibraltar]
is connected with that of India, and that there is thus only one ocean."
It is known that this passage from _The Philosopher_ influenced Columbus
in his undertaking to reach the Orient by sailing west from the coast of
Spain.
We must pass over Aristotle's observation of a relationship (homology)
between the arms of man, the forelegs of quadrupeds, the wings of birds,
and the pectoral fins of fishes, as well as many other truths to which
his genius for generalization led him.
In the field of botany Aristotle had a wide knowledge of natural
phenomena, and raised general questions as to mode of propagation,
nourishment, relation of plants to animals, etc. His pupil and lifelong
friend, and successor as leader of the Peripatetic school of philosophy,
Theophrastus, combined a knowledge of mathematics, astronomy, botany,
and mineralogy. His _History of Plants_ describes about five hundred
species. At the same time he treats the general principles of botany,
the distribution of plants, the nourishment of the plant through leaf as
well as root, the sexuality of date palm and terebinth. He lays great
stress on the uses of plants. His classification of plants is inferior
to Aristotle's classification of animals. His views in reference to
spontaneous generation are more guarded than those of his master. His
work _On Stones_ is dominated by the practical rather than the
generalizing spirit. It is evidently inspired by a knowledge of mines,
such as the celebrated Laurium, from which Athens drew its supply of
silver, and the wealth from which enabled the Athenians to develop a
sea-power that overmatched that of the Persians. Even to-day enough
remains of the galleries, shafts, scoria, mine-lamps, and other utensils
to give a clear idea of this scene of ancient industry. Theophrastus
considered the medicinal uses of minerals as well as of plants.
We have failed to mention Hippocrates (460-370 B.C.), the Father of
Medicine, in whom is found an intimate union of practical science and
speculative philosophy. We must also pass over such later Greek
scientists as Aristarchus and Hipparchus who confuted the theories of
Pythagoras and Plato in reference to the relative distances of the
heavenly bodies from the earth. Archimedes of Syracuse demands, however,
particular consideration. He lived in the third century B.C., and has
been called the greatest mathematician of antiquity. In him we find the
devotion to the abstract that marked the Greek intelligence. He went so
far as to say that every kind of art is ignoble if connected with daily
needs. His interest lay in abstruse mathematical problems. His special
pride was in having determined the relative dimensions of the sphere and
the enclosing cylinder. He worked out the principle of the lever. "Give
me," he said, "a place on which to stand and I will move the earth." He
approximated more closely than the Egyptians the solution of the problem
of the relation between the area of a circle and the radius. His work
had practical value in spite of himself. At the request of his friend
the King of Sicily, he applied his ingenuity to discover whether a
certain crown were pure gold or alloyed with silver, and he hit upon a
method which has found many applications in the industries. His name is
associated with the endless screw. In fact, his practical contrivances
won such repute that it is not easy to separate the historical facts
from the legends that enshroud his name. He aided in the defense of his
native city against the Romans in 212 B.C., and devised war-engines with
which to repel the besiegers. After the enemy had entered the city, says
tradition, he stood absorbed in a mathematical problem which he had
diagrammed on the sand. As a rude Roman soldier approached, Archimedes
cried, "Don't spoil my circles," and was instantly killed. The
victorious general, however, buried him with honor, and on the tomb of
the mathematician caused to be inscribed the sphere with its enclosing
cylinder. The triumphs of Greek abstract thought teach the lesson that
practical men should pay homage to speculation even when they fail to
comprehend a fraction of it.
REFERENCES
Aristotle, _Historia Animalium_; translated by D'A. W. Thompson. (Vol.
IV of the _Works of Aristotle Translated into English_. Oxford:
Clarendon Press.)
A. B. Buckley (Mrs. Buckley Fisher), _A Short History of Natural
Science_.
G. H. Lewes, _Aristotle; A Chapter in the History of Science_.
T. E. Lones, _Aristotle's Researches in Natural Science_.
D'A. W. Thompson, _On Aristotle as a Biologist_.
William Whewell, _History of the Inductive Sciences_.
Alfred Weber, _History of Philosophy_.
CHAPTER III
SCIENTIFIC THEORY SUBORDINATED TO APPLICATION--ROME: VITRUVIUS
Vitruvius was a cultured engineer and architect. He was employed in the
service of the Roman State at the time of Augustus, shortly before the
beginning of the Christian era. He planned basilicas and aqueducts, and
designed powerful war-engines capable of hurling rocks weighing three or
four hundred pounds. He knew the arts and the sciences, held lofty
ideals of professional conduct and dignity, and was a diligent student
of Greek philosophy.
We know of him chiefly from his ten short books on Architecture (_De
Architectura, Libri Decem_), in which he touches upon much of the
learning of his time. Architecture for Vitruvius is a science arising
out of many other sciences. Practice and theory are its parents. The
merely practical man loses much by not knowing the background of his
activities; the mere theorist fails by mistaking the shadow for the
substance. Vitruvius in the theoretical and historical parts of his book
draws largely on Greek writers; but in the parts bearing on practice he
sets forth, with considerable shrewdness, the outcome of years of
thoughtful professional experience. One cannot read his pages without
feeling that he is more at home in the concrete than in the abstract and
speculative, in describing a catapult than in explaining a scientific
theory or a philosophy. He was not a Plato or an Archimedes, but an
efficient officer of State, conscious of indebtedness to the great
scientists and philosophers. With a just sense of his limitations he
undertook to write, not as a literary man, but as an architect. His
education had been mainly professional, but, the whole circle of
learning being one harmonious system, he had been drawn to many branches
of knowledge in so far as they were related to his calling.
In the judgment of Vitruvius an architect should be a good writer, able
to give a lucid explanation of his plans, a skillful draftsman, versed
in geometry and optics, expert at figures, acquainted with history,
informed in the principles of physics and of ethics, knowing something
of music (tones and acoustics), not ignorant of law, or of hygiene, or
of the motions, laws, and relations to each other of the heavenly
bodies. For, since architecture "is founded upon and adorned with so
many different sciences, I am of opinion that those who have not, from
their early youth, gradually climbed up to the summit, cannot without
presumption, call themselves masters of it."
Vitruvius was far from sharing the view of Archimedes that art which was
connected with the satisfaction of daily needs was necessarily ignoble
and vulgar. On the contrary, his interest centered in the practical; and
he was mainly concerned with scientific theory by reason of its
application in the arts. Geometry helped him plan a staircase; a
knowledge of tones was necessary in discharging catapults; law dealt
with boundary-lines, sewage-disposal, and contracts; hygiene enabled the
architect to show a Hippocratic wisdom in the choice of building-sites
with due reference to airs and waters. Vitruvius had the Roman
practical and regulative genius, not the abstract and speculative genius
of Athens.
The second book begins with an account of different philosophical views
concerning the origin of matter, and a discussion of the earliest
dwellings of man. Its real theme, however, is building-material--brick,
sand, lime, stone, concrete, marble, stucco, timber, pozzolano. In
reference to the last (volcanic ash combined with lime and rubble to
form a cement) Vitruvius writes in a way that indicates a discriminating
knowledge of geological formations. Likewise his discussion of the
influence of the Apennines on the rainfall, and, consequently, on the
timber of the firs on the east and west of the range, shows a grasp of
meteorological principles. His real power to generalize is shown in
connection with his specialty, in his treatment of the sources of
building-material, rather than in his consideration of the origin of
matter.
Similarly the fifth book begins with a discussion of the theories of
Pythagoras, but its real topic is public buildings--fora, basilicas,
theaters, baths, palæstras, harbors, and quays. In the theaters bronze
vases of various sizes, arranged according to Pythagorean musical
principles, were to be used in the auditorium to reinforce the voice of
the actor. (This recommendation was misunderstood centuries later, when
Vitruvius was considered of great authority, and led to the futile
practice of placing earthenware jars beneath the floors of church
choirs.) According to our author, "The voice arises from flowing breath,
sensible to the hearing through its percussion on the air." It is
compared to the wavelets produced by a stone dropped in water, only that
in the case of sound the waves are not confined to one plane. This
generalization concerning the nature of sound was probably not original,
however; it may have been suggested to Vitruvius by one of the
Aristotelian writings.
The seventh book treats of interior decoration--mosaic floors, gypsum
mouldings, wall painting, white lead, red lead, verdigris, mercury
(which may be used to recover gold from worn-out pieces of embroidery),
encaustic painting with hot wax, colors (black, blue, genuine and
imitation murex purple). The eighth book deals with water and with
hydraulic engineering, hot springs, mineral waters, leveling
instruments, construction of aqueducts, lead and clay piping. Vitruvius
was not ignorant of the fact that water seeks its own level, and he even
argued that air must have weight in order to account for the rise of
water in pumps. In his time it was more economical to convey the hard
water by aqueducts than by such pipes as could then be constructed. The
ninth book undertakes to rehearse the elements of geometry and
astronomy--the signs of the zodiac, the sun, moon, planets, the phases
of the moon, the mathematical divisions of the gnomon, the use of the
sundial, etc. One feels in reading Vitruvius that his purpose was to
turn to practical account what he had gained from the study of the
sciences; and, at the same time, one is convinced that his applications
tend to react on theoretical knowledge, and lead to new insights through
the suggestion of new problems.
The tenth book of the so-called _De Architectura_ is concerned with
machinery--windmills, windlasses, axles, pulleys, cranes, pumps,
fire-engines, revolving spiral tubes for raising water, wheels for
irrigation worked by water-power, wheels to register distance traveled
by land or water, scaling-ladders, battering-rams, tortoises, catapults,
scorpions, and ballistæ. On the subject of war-engines Vitruvius speaks
with special authority, as he had served, probably as military engineer,
under Julius Cæsar in 46 B.C., and had been appointed superintendent of
ballistæ and other military engines in the time of Augustus. It was to
the divine Emperor that his book was dedicated as a protest against the
administration of Roman public works. In its pages we see reflected the
life of a nation employed in conquering and ruling the world, with a
genius more distinguished for practical achievement than for theory and
speculation. Its author is truly representative of Roman culture, for
nearly everything that Rome had of a scientific and intellectual sort it
drew from Greece, and it selected that part of Greek wisdom that
ministered to the daily needs of the times. In his work on architecture,
Vitruvius shows himself a diligent and devoted student of the sciences
in order that he may turn them to account in his own department of
technology.
If you glance at the study of mathematics, astronomy, and medicine among
the Romans prior to the time of Greek influence, you find that next to
nothing had been accomplished. Their method of field measurement was far
less developed than the ancient Egyptian geometry, and even for it (as
well as for their system of numerals) they were indebted to the
Etruscans. The history of astronomy has nothing to record of scientific
accomplishment on the part of the Romans. They reckoned time by months,
and in the earlier period kept a rude tally of the years by driving
nails into a statue of Janus, the ancient sun-god. As we shall see, they
were unable to regulate the calendar. Again, so far were they from
contributing to the development of medicine that they had no physicians
for the six hundred years preceding the coming of Greek science. A
medical slave acted as overseer of the family health, and disease was
combated in primitive fashion by prayers and offerings to various gods,
who were supposed to furnish general health or to influence the
functions of the different parts of the body. So rude was the native
culture of the Romans that it is doubtful whether they had any schools
before the advent of Greek learning. The girls were trained by their
mothers, the boys either by their fathers or by some master to whom they
were apprenticed.
The Greeks were conquered by the Romans in 146 B.C., but before that
time Roman life and institutions had been touched by Hellenic culture.
Cato the Censor (who died in 149 B.C.) and other conservatives tried in
vain to resist the invasion of Greek science, philosophy, and
refinement. After the conquest of Greece the master became pupil, and
the conqueror was taken captive. The Romans, however, never rose to
preëminence in science or the fine arts. A further development in
technology corresponded more closely to their national needs, and in
this field they came undoubtedly to surpass the Greeks. Bridges, ships,
military roads, war-engines, aqueducts, public buildings, organization
of the State and the army, the formulation of legal procedure, the
enactment and codification of laws, were necessary to secure and
maintain the Empire. The use in building construction of a knowledge of
the right-angled triangle as well as other matters known to the
Egyptians and Babylonians, and Archimedes' method of determining
specific gravity were of peculiar interest to the practical Romans.
Julius Cæsar, 102-44 B.C., instituted a reform of the calendar. This was
very much needed, as the Romans were eighty-five days out of their
reckoning, and the date for the spring equinox, instead of coming at the
proper time, was falling in the middle of winter. An Alexandrian
astronomer (Sosigenes) assisted in establishing the new (Julian)
calendar. The principle followed was based on ancient Egyptian practice.
Among the 365 days of the year was to be inserted, or intercalated,
every fourth year an extra day. This the Romans did by giving to two
days in leap-year the same name; thus the sixth day before the first of
March was repeated, and leap-year was known as a bissextile year. Cæsar,
trained himself in the Greek learning and known to his contemporaries as
a writer on mathematics and astronomy, also planned a survey of the
Empire, which was finally carried into execution by Augustus.
There is evidence that the need of technically trained men became more
and more pressing as the Empire developed. At first there were no
special teachers or schools. Later we find mention of teachers of
architecture and mechanics. Then the State came to provide classrooms
for technical instruction and to pay the salaries of the teachers.
Finally, in the fourth century A.D., further measures were adopted by
the State. The Emperor Constantine writes to one of his officials: "We
need as many engineers as possible. Since the supply is small, induce to
begin this study youths of about eighteen years of age who are already
acquainted with the sciences required in a general education. Relieve
their parents from the payment of taxes, and furnish the students with
ample means."
Pliny the Elder (23-79 A.D.), in the encyclopedic work which he compiled
under the title _Natural History_, drew freely on hundreds of Greek and
Latin authors for his facts and fables. In the selection that he made
from his sources can be traced, as in the work of Vitruvius and other
Latin writers, the tendency to make the sciences subservient to the
arts. For example, the one thousand species of plants of which he makes
mention are considered from the medicinal or from the economic point of
view. It was largely in the interest of their practical uses that the
Roman regarded both plants and animals; his chief motive was not a
disinterested love of truth. Pliny thought that each plant had its
special virtue, and much of his botany is applied botany. So
comprehensive a work as the _Natural History_ was sure to contain
interesting anticipations of modern science. Pliny held that the earth
hovers in the heavens upheld by the air, that its sphericity is proved
by the fact that the mast of a ship approaching the land is visible
before the hull comes in sight. He also taught that there are
inhabitants on the other side of the earth (antipodes), that at the time
of the winter solstice the polar night must last for twenty-four hours,
and that the moon plays a part in the production of the tides.
Nevertheless, the whole book is permeated by the idea that the purpose
of nature is to minister to the needs of man.
It further marks the practical spirit among the Romans that a work on
agriculture by a Carthaginian (Mago) was translated by order of the
Senate. Cato (234-149 B.C.), so characteristically Roman in his genius,
wrote (_De Re Rustica_) concerning grains and the cultivation of fruits.
Columella wrote treatises on agriculture and forestry. Among the
technical writings of Varro besides the book on agriculture, which is
extant, are numbered works on law, mensuration, and naval tactics.
It was but natural that at the time of the Roman Empire there should be
great advances in medical science. A Roman's interest in a science was
keen when it could be proved to have immediate bearing on practical
life. The greatest physician of the time, however, was a Greek. Galen
(131-201 A.D.), who counted himself a disciple of Hippocrates, began to
practice at Rome at the age of thirty-three. He was the only
experimental physiologist before the time of Harvey. He studied the
vocal apparatus in the larynx, and understood the contraction and
relaxation of the muscles, and, to a considerable extent, the motion of
the blood through the heart, lungs, and other parts of the body. He was
a vivisector, made sections of the brain in order to determine the
functions of its parts, and severed the gustatory, optic, and auditory
nerves with a similar end in view. His dissections were confined to the
lower animals. Yet his works on human anatomy and physiology were
authoritative for the subsequent thirteen centuries. It is difficult to
say how much of the work and credit of this practical scientist is to be
given to the race from which he sprang and how much to the social
environment of his professional career. (In the ruins of Pompeii,
destroyed in 79 A.D., have been recovered some two hundred kinds of
surgical instrument, and in the later Empire certain departments of
surgery developed to a degree not surpassed till the sixteenth century.)
If it is too much to say that the Roman environment is responsible for
Galen's achievements, we can at least say that it was characteristic
of the Roman people to welcome such science as his, capable of
demonstrating its utility.
Dioscorides was also a Greek who, long resident at Rome, applied his
science in practice. He knew six hundred different plants, one hundred
more than Theophrastus. The latter laid much stress, as we have seen in
the preceding chapter, on the medicinal properties of plants, but in
this respect he was outdone by Dioscorides (as well as by Pliny).
Theophrastus was the founder of the science of botany, Dioscorides the
founder of materia medica.
Quintilian, born in Spain, spent the greater part of his life as a
teacher of rhetoric in Rome. He valued the sciences, not on their own
account, but as they might subserve the purposes of the orator. Music,
astronomy, logic, and even theology, might be exploited as aids to
public speech. In the time of Quintilian (first century A.D.), as in our
own, oratory was considered one of the great factors in a young man's
success; mock debating contests were frequent, and the periods of the
future orators reverberated among the seven hills of Rome. To him our
schools are also indebted for the method of teaching foreign languages
by declensions, conjugations, vocabularies, formal rhetoric and
annotations. He considered ethics the most valuable part of philosophy.
In fact, it would not be pressing our argument unduly to say that, so
far as the minds of the Romans turned to speculation, it was the
tendency to practical philosophy--Epicureanism or Stoicism--that was
most characteristic. This was true even of Lucretius (98-55 B.C.),
author of the noble poem concerning the Nature of Things (_De Rerum
Natura_). In this work he writes under the inspiration of Greek
philosophy. His model was a poem by Empedocles on Nature, the grand
hexameters of which had fascinated the Roman poet. The distinctive
feature of the work of Lucretius is the purpose, ethical rather than
speculative, to curb the ambition, passion, luxury of those hard pagan
times, and likewise to free the souls of his countrymen from the fear of
the gods and the fear of death, and to replace superstition by peace of
mind and purity of heart.
From the work on Physical Science (_Quæstionum Naturalium, Libri
Septem_) of Seneca, the tutor of Nero, we learn that the Romans made use
of globes filled with water as magnifiers, employed hothouses in their
highly developed horticulture, and observed the refraction of colors by
the prism. At the same time the book contains interesting conjectures in
reference to the relation of earthquakes and volcanoes, and to the fact
that comets travel in fixed orbits. In the main, however, this work is
an attempt to find a basis for ethics in natural phenomena. Seneca was a
Stoic, as Lucretius was an Epicurean, moralist.
When we glance back at the culture, or cultures, of the great peoples of
antiquity, Egyptian, Babylonian, Greek, and Roman, that which had its
center on the banks of the Tiber offers the closest analogy to our own.
Among English-speaking peoples as among the Romans there is noticeable a
certain contempt for scientific studies strangely mingled with an
inclination to exploit all theory in the interest of immediate
application. An English author, writing in 1834, remarks that the
Romans, eminent in war, in polite literature, and civil policy, showed
at all times a remarkable indisposition to the pursuit of mathematical
and physical science. Geometry and astronomy, so highly esteemed by the
Greeks, were not merely disregarded by the Italians, but even considered
beneath the attention of a man of good birth and liberal education; they
were imagined to partake of a mechanical, and therefore servile,
character. "The results were seen to be made use of by the mechanical
artist, and the abstract principles were therefore supposed to be, as it
were, contaminated by his touch. This unfortunate peculiarity in the
taste of his countrymen is remarked by Cicero. And it may not be
irrelevant to inquire, whether similar prejudices do not prevail to some
extent even among ourselves." To Americans also must be attributed an
impatience of theory as theory, and a predominant interest in the
applications of science.
REFERENCES
Lucretius, _The Nature of Things_; translated by H. A. J. Munro.
Pliny, _Natural History_; translated by Philemon Holland.
Professor Baden Powell, _History of Natural Philosophy_.
Seneca, _Physical Science_; translated by John Clarke.
Vitruvius, _Architecture_; translated by Joseph Gwilt, 1826.
Vitruvius, _Architecture_; translated by Professor M. H. Morgan, 1914.
CHAPTER IV
THE CONTINUITY OF SCIENCE--THE MEDIEVAL CHURCH AND THE ARABS
Learning has very often and very aptly been compared to a torch passed
from hand to hand. By the written sign or spoken word it is transmitted
from one person to another. Very little advance in culture could be made
even by the greatest man of genius if he were dependent, for what
knowledge he might acquire, merely on his own personal observation.
Indeed, it might be said that exceptional mental ability involves a
power to absorb the ideas of others, and even that the most original
people are those who are able to borrow the most freely.
In recalling the lives of certain great men we may at first be inclined
to doubt this truth. How shall we account for the part played in the
progress of civilization by the rustic Burns, the village-bred
Shakespeare, or by Lincoln the frontiersman? When, however, we
scrutinize the case of any one of these, we discover, of course,
exceptional natural endowment, susceptibility to mental influence,
remarkable powers of acquisition, but no ability to produce anything
absolutely original. In the case of Lincoln, for example, we find that
in his youth he was as distinguished by diligence in study as by
physical stature and prowess. After he withdrew from school, he read,
wrote, and ciphered (in the intervals of manual work) almost
incessantly. He read everything he could lay hands on. He copied out
what most appealed to him. A few books he read and re-read till he had
almost memorized them. What constituted his library? The Bible, _Æsop's
Fables_, _Robinson Crusoe_, _The Pilgrim's Progress_, a _Life of
Washington_, a _History of the United States_. These established for him
a vital relation with the past, and laid the foundations of a democratic
culture; not the culture of a Chesterfield, to be sure, but something
immeasurably better, and none the less good for being almost universally
accessible. Lincoln developed his logical powers conning the dictionary.
Long before he undertook the regular study of the law, he spent long
hours poring over the revised statutes of the State in which he was
living. From a book he mastered with a purpose the principles of
grammar. In the same spirit he learned surveying, also by means of a
book. There is no need to ignore any of the influences that told
toward the development of this great statesman, the greatest of
English-speaking orators, but it is evident that remote as was his
habitation from all the famous centers of learning he was, nevertheless,
early immersed in the current of the world's best thought.
Similarly, in the history of science, every great thinker has his
intellectual pedigree. Aristotle was the pupil of Plato, Plato was the
disciple of Socrates, and the latter's intellectual genealogy in turn
can readily be traced to Thales, and beyond--to Egyptian priests and
Babylonian astronomers.
The city of Alexandria, founded by the pupil of Aristotle in 332 B.C.,
succeeded Athens as the center of Greek culture. On the death of
Alexander the Great, Egypt was ruled by one of his generals, Ptolemy,
who assumed the title of king. This monarch, though often engaged in
war, found time to encourage learning, and drew to his capital scholars
and philosophers from Greece and other countries. He wrote himself a
history of Alexander's campaigns, and instituted the famous library of
Alexandria. This was greatly developed (and supplemented with schools of
science and an observatory) by his son Ptolemy Philadelphus, a prince
distinguished by his zeal in promoting the good of the human species. He
collected vast numbers of manuscripts, had strange animals brought from
distant lands to Alexandria, and otherwise promoted scientific research.
This movement was continued under Ptolemy III (246-221 B.C.).
Something has already been said of the early astronomers and
mathematicians of Alexandria. The scientific movement of the later
Alexandrian period found its consummation in the geographer, astronomer,
and mathematician Claudius Ptolemy (not to be confused with the rulers
of that name). He was most active 127-151 A.D., and is best known by his
work the _Syntaxis_, which summarized what was known in astronomy at
that time. Ptolemy drew up a catalogue of 1080 stars based on the
earlier work of Hipparchus. He followed that astronomer in teaching that
the earth is the center of the movement of the heavenly bodies, and this
geocentric system of the heavens became known as the Ptolemaic system of
astronomy. To Hipparchus and Ptolemy we owe also the beginnings of the
science of trigonometry. The _Syntaxis_ sets forth his method of
drawing up a table of chords. For example, the side of a hexagon
inscribed in a circle is equal to the radius, and is the chord of 60°,
or of the sixth part of the circle. The radius is divided into sixty
equal parts, and these again divided and subdivided sexagesimally. The
smaller divisions and the subdivisions are known as prime minute parts
and second minute parts (_partes minutæ primæ_ and _partes minutæ
secundæ_), whence our terms "minute" and "second." The sexagesimal
method of dividing the circle and its parts was, as we have seen in the
first chapter, of Babylonian origin.
Ptolemy was the last of the great Greek astronomers. In the fourth
century and at the beginning of the fifth, Theon and his illustrious
daughter Hypatia commented on and taught the astronomy of Ptolemy. In
the Greek schools of philosophy Plato's doctrine of the supreme reality
of the invisible world was harmonized for a time with Christian
mysticism, but these schools were suppressed at the beginning of the
sixth century. The extinction of scientific and of all other learning
seemed imminent.
What were the causes of this threatened break in the historical
continuity of science? They were too many and too varied to admit of
adequate statement here. From the latter part of the fourth century the
Roman Empire had been overrun by the Visigoths, the Vandals, the Huns,
the Ostrogoths, the Lombards, and other barbarians. Even before these
incursions learning had suffered under the calamity of war. In the time
of Julius Cæsar the larger of the famous libraries of Alexandria,
containing, it is computed, some 490,000 rolls, caught fire from ships
burning in the harbor, and perished. This alone involved an incalculable
setback to the march of scientific thought.
Another influence tending to check the advance of the sciences was the
clash between Christian and Pagan ideals. To many of the bishops of the
Church the aims and pursuits of science seemed vain and trivial when
compared with the preservation of purity of character or the assurance
of eternal felicity. Many were convinced that the end of the world was
at hand, and strove to fix their thoughts solely on the world to come.
Their austere disregard of this life found some support in a noble
teaching of the Stoic philosophy that death itself is no evil to the
just man. The early Christian teachers held that the body should be
mortified if it interfered with spiritual welfare. Disease is a
punishment, or a discipline to be patiently borne. One should choose
physical uncleanliness rather than run any risk of moral contamination.
It is not impossible for enlightened people at the present time
to assume a tolerant attitude toward the worldly Greeks or the
other-worldly Christians. At that time, however, mutual antipathy was
intense. The long and cruel war between science and Christian theology
had begun.
Not all the Christian bishops, to be sure, took a hostile view of Greek
learning. Some regarded the great philosophers as the allies of the
Church. Some held that churchmen should study the wisdom of the Greeks
in order the better to refute them. Others held that the investigation
of truth was no longer necessary after mankind had received the
revelation of the gospel. One of the ablest of the Church Fathers
regretted his early education and said that it would have been better
for him if he had never heard of Democritus. The Christian writer
Lactantius asked shrewdly whence atoms came, and what proof there was of
their existence. He also allowed himself to ridicule the idea of the
antipodes, a topsy-turvy world of unimaginable disorder. In 389 A.D. one
of the libraries at Alexandria was destroyed and its books were pillaged
by the Christians. In 415 Hypatia, Greek philosopher and mathematician,
was murdered by a Christian mob. In 642 the Arabs having pushed their
conquest into northern Africa gained possession of Alexandria. The cause
of learning seemed finally and irrecoverably lost.
The Arab conquerors, however, showed themselves singularly hospitable to
the culture of the nations over which they had gained control. Since the
time of Alexander there had been many Greek settlers in the larger
cities of Syria and Persia, and here learning had been maintained in the
schools of the Jews and of a sect of Christians (Nestorians), who were
particularly active as educators from the fifth century to the eleventh.
The principal Greek works on science had been translated into Syrian.
Hindu arithmetic and astronomy had found their way into Persia. By the
ninth century all these sources of scientific knowledge had been
appropriated by the Arabs. Some fanatics among them, to be sure, held
that one book, the Koran, was of itself sufficient to insure the
well-being of the whole human race, but happily a more enlightened view
prevailed.
In the time of Harun Al-Rashid (800 A.D.), and his son, the Caliphate
of Bagdad was the center of Arab science. Mathematics and astronomy were
especially cultivated; an observatory was established; and the work of
translation was systematically carried on by a sort of institute of
translators, who rendered the writings of Aristotle, Hippocrates, Galen,
Euclid, Ptolemy, and other Greek scientists, into Arabic. The names of
the great Arab astronomers and mathematicians are not popularly known to
us; their influence is greater than their fame. One of them describes
the method pursued by him in the ninth century in taking measure of the
circumference of the earth. A second developed a trigonometry of sines
to replace the Ptolemaic trigonometry of chords. A third made use of the
so-called Arabic (really Hindu) system of numerals, and wrote the first
work on Algebra under that name. In this the writer did not aim at the
mental discipline of students, but sought to confine himself to what is
easiest and most useful in calculation, "such as men constantly require
in cases of inheritance, legacies, partition, law-suits, and trade, and
in all their dealings with one another, or where the measuring of lands,
the digging of canals, geometrical computation, and other objects of
various sorts and kinds are concerned."
In the following centuries Arab institutions of higher learning were
widely distributed and the flood-tide of Arab science was borne farther
west. At Cairo about the close of the tenth century the first accurate
records of eclipses were made, and tables were constructed of the
motions of the sun, moon, and planets. Here as elsewhere the Arabs
displayed ingenuity in the making of scientific apparatus, celestial
globes, sextants of large size, quadrants of various sorts, and
contrivances from which in the course of time were developed modern
surveying instruments for measuring horizontal and vertical angles.
Before the end of the eleventh century an Arab born at Cordova, the
capital of Moorish Spain, constructed the Toletan Tables. These were
followed in 1252 by the publication of the Alphonsine Tables, an event
which astronomers regard as marking the dawn of European science.
Physics and chemistry, as well as mathematics and astronomy, owe much in
their development to the Arabs. An Arabian scientist of the eleventh
century studied the phenomena of the reflection and refraction of light,
explained the causes of morning and evening twilight, understood the
magnifying power of lenses and the anatomy of the human eye. Our use of
the terms retina, cornea, and vitreous humor may be traced to
the translation of his work on optics. The Arabs also made fair
approximations to the correct specific weights of gold, copper, mercury,
and lead. Their alchemy was closely associated with metallurgy, the
making of alloys and amalgams, and the handicrafts of the goldsmiths and
silversmiths. The alchemists sought to discover processes whereby one
metal might be transmuted into another. Sulphur affected the color and
substance. Mercury was supposed to play an important part in metal
transmutations. They thought, for example, that tin contained more
mercury than lead, and that the baser, more unhealthy metal might be
converted into the nobler and more healthy by the addition of mercury.
They even sought for a substance that might effect all transmutations,
and be for mankind a cure for all ailments, even that of growing old.
The writings that have been attributed to Geber show the advances that
chemistry made through the experiments of the Arabs. They produced
sulphuric and nitric acids, and _aqua regia_, able to dissolve gold, the
king of metals. They could make use of wet methods, and form metallic
salts such as silver nitrate. Laboratory processes like distilling,
filtering, crystallization, sublimation, became known to the Europeans
through them. They obtained potash from wine lees, soda from sea-plants,
and from quicksilver the mercuric oxide which played so interesting a
part in the later history of chemistry.
Much of the science lore of the Arabs arose from their extensive trade,
and in the practice of medicine. They introduced sugar-cane into Europe,
improved the methods of manufacturing paper, discovered a method of
obtaining alcohol, knew the uses of gypsum and of white arsenic, were
expert in pharmacy and learned in materia medica. They are sometimes
credited with introducing to the West the knowledge of the mariner's
compass and of gunpowder.
Avicenna (980-1037), the Arab physician, not only wrote a large work on
medicine (the _Canon_) based on the lore of Galen, which was used as a
text-book for centuries in the universities of Europe, but wrote
commentaries on all the works of Aristotle. For Averroës (1126-1198),
the Arab physician and philosopher, was reserved the title "The
Commentator," due to his devotion to the works of the Greek biologist
and philosopher. It was through the commentaries of Averroës that
Aristotelian science became known in Europe during the Middle Ages. In
his view Aristotle was the founder and perfecter of science; yet he
showed an independent knowledge of physics and chemistry, and wrote on
astronomy and medicine as well as philosophy. He set forth the facts in
reference to natural phenomena purely in the interests of the truth. He
could not conceive of anything being created from nothing. At the same
time he taught that God is the essence, the eternal cause, of progress.
It is in humanity that intellect most clearly reveals itself, but there
is a transcendent intellect beyond, union with which is the highest
bliss of the individual soul. With the death of the Commentator the
culture of liberal science among the Arabs came to an end, but his
influence (and through him that of Aristotle) was perpetuated in all the
western centers of education.
The preservation of the ancient learning had not, however, depended
solely on the Arabs. At the beginning of the sixth century, before the
taking of Alexandria by the followers of Mohammed, St. Benedict had
founded the monastery of Monte Cassino in Italy. Here was begun the
copying of manuscripts, and the preparation of compendiums treating of
grammar, dialectic, rhetoric, arithmetic, astronomy, music, and
geometry. These were based on ancient, Roman writings. Works like
Pliny's _Natural History_, the encyclopedia of the Middle Ages, had
survived all the wars by which Rome had been devastated. Learning, which
in Rome's darkest days had found refuge in Britain and Ireland, returned
book in hand. Charlemagne (800) called Alcuin from York to instruct
princes and nobles at the Frankish court. At this same palace school
half a century later the Irishman Scotus Erigena exhibited his learning,
wit, and logical acumen. In the tenth century Gerbert (Pope Sylvester
II) learned mathematics at Arab schools in Spain. The translation of
Arab works on science into the Latin language, freer intercourse of
European peoples with the East through war and trade, economic
prosperity, the liberation of serfs and the development of a well-to-do
middle class, the voyages of Marco Polo to the Orient, the founding of
universities, the encouragement of learning by the Emperor Frederick II,
the study of logic by the schoolmen, were all indicative of a new era in
the history of scientific thought.
The learned Dominican Albertus Magnus (1193-1280) was a careful student
of Aristotle as well as of his Arabian commentators. In his many books
on natural history he of course pays great deference to the Philosopher,
but he is not devoid of original observation. As the official visitor of
his order he had traveled through the greater part of Germany on foot,
and with a keen eye for natural phenomena was able to enrich botany and
zoölogy by much accurate information. His intimacy with the details of
natural history made him suspected by the ignorant of the practice of
magical arts.
His pupil and disciple Thomas Aquinas (1227-1274) was the philosopher
and recognized champion of the Christian Church. In 1879 Pope Leo XIII,
while proclaiming that every wise saying, every useful discovery, by
whomsoever it may be wrought, should be welcomed with a willing and
grateful mind, exhorted the leaders of the Roman Catholic Church to
restore the golden wisdom of St. Thomas and to propagate it as widely as
possible for the good of society and the advancement of all the
sciences. Certainly the genius of St. Thomas Aquinas seems comprehensive
enough to embrace all science as well as all philosophy from the
Christian point of view. According to him there are two sources of
knowledge, reason and revelation. These are not irreconcilably opposed.
The Greek philosophers speak with the voice of reason. It is the duty of
theology to bring all knowledge into harmony with the truths of
revelation imparted by God for the salvation of the human race. Averroës
is in error when he argues the impossibility of something being created
from nothing, and again when he implies that the individual intellect
becomes merged in a transcendental intellect; for such teaching would be
the contrary of what has been revealed in reference to the creation of
the world and the immortality of the individual soul. In the
accompanying illustration we see St. Thomas inspired by Christ in glory,
guided by Moses, St. Peter, and the Evangelists, and instructed by
Aristotle and Plato. He has overcome the heathen philosopher Averroës,
who lies below discomfited.
[Illustration: ST. THOMAS AQUINAS OVERCOMING AVERROËS]
The English Franciscan Roger Bacon (1214-1294) deserves to be mentioned
with the two great Dominicans. He was acquainted with the works of the
Greek and Arabian scientists. He transmitted in a treatise that fell
under the eye of Columbus the view of Aristotle in reference to the
proximity of another continent on the other side of the Atlantic; he
anticipated the principle on which the telescope was afterwards
constructed; he advocated basing natural science on experience and
careful observation rather than on a process of reasoning. Roger Bacon's
writings are characterized by a philosophical breadth of view. To his
mind the earth is only an insignificant dot in the center of the vast
heavens.
In the centuries that followed the death of Bacon the relation of this
planet to the heavenly bodies was made an object of study by a
succession of scientists who like him were versed in the achievements of
preceding ages. Peurbach (1423-1461), author of _New Theories of the
Planets_, developed the trigonometry of the Arabians, but died before
fulfilling his plan to give Europe an epitome of the astronomy of
Ptolemy. His pupil, Regiomontanus, however, more than made good the
intentions of his master. The work of Peurbach had as commentator the
first teacher in astronomy of Copernicus (1473-1543). Later Copernicus
spent nine years in Italy, studying at the universities and acquainting
himself with Ptolemaic and other ancient views concerning the motions of
the planets. He came to see that the apparent revolution of the heavenly
bodies about the earth from east to west is really owing to the
revolution of the earth on its axis from west to east. This view was so
contrary to prevailing beliefs that Copernicus refused to publish his
theory for thirty-six years. A copy of his book, teaching that our earth
is not the center of the universe, was brought to him on his deathbed,
but he never opened it.
Momentous as was this discovery, setting aside the geocentric system
which had held captive the best minds for fourteen slow centuries and
substituting the heliocentric, it was but a link in the chain of
successes in astronomy to which Tycho Brahe, Kepler, Galileo, Newton,
and their followers contributed.
REFERENCES
_The Catholic Encyclopedia._
J. L. E. Dreyer, _History of the Planetary Systems_.
_Encyclopædia Britannica._ Arabian Philosophy; Roger Bacon.
W. J. Townsend, _The Great Schoolmen of the Middle Ages_.
R. B. Vaughan, _St. Thomas of Aquin; his Life and Labours_.
Andrew D. White, _A History of the Warfare of Science with Theology in
Christendom_.
CHAPTER V
THE CLASSIFICATION OF THE SCIENCES--FRANCIS BACON
The preceding chapter has shown that there is a continuity in the
development of single sciences. The astronomy, or the chemistry, or the
mathematics, of one period depends so directly on the respective science
of the foregoing period, that one feels justified in using the term
"growth," or "evolution," to describe their progress. Now a vital
relationship can be observed not only among different stages of the same
science, but also among the different sciences. Physics, astronomy, and
chemistry have much in common; geometry, trigonometry, arithmetic, and
algebra are called "branches" of mathematics; zoölogy and botany are
biological sciences, as having to do with living species. In the century
following the death of Copernicus, two great scientists, Bacon and
Descartes, compared all knowledge to a tree, of which the separate
sciences are branches. They thought of all knowledge as a living
organism with an interconnection or continuity of parts, and a
capability of growth.
By the beginning of the seventeenth century the sciences were so
considerable that in the interest of further progress a comprehensive
view of the tree of knowledge, a survey of the field of learning, was
needed. The task of making this survey was undertaken by Francis Bacon,
Lord Verulam (1561-1626). His classification of human knowledge was
celebrated, and very influential in the progress of science. He kept one
clear purpose in view, namely, the control of nature by man. He wished
to take stock of what had already been accomplished, to supply
deficiencies, and to enlarge the bounds of human empire. He was acutely
conscious that this was an enterprise too great for any one man, and he
used his utmost endeavors to induce James I to become the patron of the
plan. His project admits of very simple statement now; he wished to edit
an encyclopedia, but feared that it might prove impossible without
coöperation and without state support. He felt capable of furnishing the
plans for the building, but thought it a hardship that he was compelled
to serve both as architect and laborer. The worthiness of these plans
was attested in the middle of the eighteenth century, when the great
French _Encyclopaedia_ was projected by Diderot and D'Alembert. The
former, its chief editor and contributor, wrote in the Prospectus: "If
we come out successful from this vast undertaking, we shall owe it
mainly to Chancellor Bacon, who sketched the plan of a universal
dictionary of sciences and arts at a time when there were not, so to
speak, either arts or sciences. This extraordinary genius, when it was
impossible to write a history of what men knew, wrote one of what they
had to learn."
Bacon, as we shall amply see, was a firm believer in the study
of the arts and occupations, and at the same time retained his
devotion to principles and abstract thought. He knew that philosophy
could aid the arts that supply daily needs; also that the arts and
occupations enriched the field of philosophy, and that the basis of our
generalizations must be the universe of things knowable. "For," he
writes, "if men judge that learning should be referred to use and
action, they judge well; but it is easy in this to fall into the error
pointed out in the ancient fable; in which the other parts of the body
found fault with the stomach, because it neither performed the office of
motion as the limbs do, nor of sense, as the head does; but yet
notwithstanding it is the stomach which digests and distributes the
aliment to all the rest. So that if any man think that philosophy and
universality are idle and unprofitable studies, he does not consider
that all arts and professions are from thence supplied with sap and
strength." For Bacon, as for Descartes, natural philosophy was the trunk
of the tree of knowledge.
Human Learning (Bacon's Classification)
Column Key:
(A) Reason Philosophy, or the Sciences
(B) Imagination Poesy
(C) Memory History
---------------------------------------------------------------------------
Philosophia prima, or sapience
-----+---+--------+----------------------+---------------------------------
(A) | | | Civil Philosophy | Intercourse
| N | | (Standards of | Business
| a | | right in:) | Government
| t | Man +---------------+------+---------------------------------
| u | | Philosophy | Body | Medicine, Athletics, etc.
| r | | of Humanity +------+---------------------------------
| a | | (Anthropology)| | Logic
| l | | | Soul |
| | | | | Ethics
| P +--------+-------------+-+------+--------+----------+-------------
| h | | | Physics | Concrete |
| i | | | (Material and | | M
| l | | | Secondary | Abstract | a
| o | | | Causes) | | t
| s | Nature | Speculative | | | h
| o | | | Metaphysics | Concrete | e
| p | | | (Form and Final | | m
| h | | | Causes) | Abstract | a
| y | +-------------+-----------------+----------+ t
| | | | Mechanics | i
| | | Operative | | c
| | | | Purified Magic | s
| +--------+-------------+----------------------------+-------------
| | God | Natural Theology, Nature of Angels and Spirits
+---+--------+--------------------------------------------------------
| Divinity | Revelation
-----+------------+--------------------------------------------------------
(B) | Narrative, or Heroical
| Dramatic
| Parabolic (Fables)
-----+-----------+------------------------+--------------------------------
(C) | | Political | Memorials
| Civil | (Civil History proper) | Antiquities
| | | Perfect History
| +-----------+------------+--------------------------------
| | | Learning
| | Literary |
| | | Arts
| +-----------+---------------------------------------------
| | Ecclesiastical
+-----------+-------------------+-------------------+-----------------
| | Bonds | Arts | Mechanical
| | (Control by Man) | | Experimental
| +-------------------+-------------------+-----------------
| | Errors | Pretergenerations
| Natural | (Anomics) | (Monsters)
| +-------------------+---------------+---------------------
| | Freedom | Generations | Astronomical Physics
| | (Nomic Law) | | Physical Geography
| | | | Physics of Matter
| | | | Organic Species
-----+-----------+-------------------+---------------+---------------------
------------+----------------------------------------------------
| Knowledge Classified (Hugo of St. Victor, d. 1141).
------------+---------------------+------------------------------
Theoretical | Theology |
| Natural Philosophy |
| (Physic) |
------------+---------------------+------------------------------
| Mathematics | Arithmetic
| | Music (study of harmony)
| | Geometry
| | Astronomy
------------+---------------------+------------------------------
Practical | Ethics, or individual morality
(Moral) | Economics, or family morality
| Politics, or civics
------------+----------------------------------------------------
Mechanical | Weaving, spinning, sewing; work in wool, flax, etc.
| Equipment--arms, ships; work in stone, wood, metal
| Navigation
| Agriculture
| Hunting, fishing, foods
| Medicine
| Theatricals--drama, music, athletics, etc.
------------+----------------------------------------------------
Logical | Oratory
| Grammar
| Dialectic
| Rhetoric
------------+----------------------------------------------------
On the other hand, he looked to the arts, crafts, and occupations as a
source of scientific principles. In his survey of learning he found some
records of agriculture and likewise of many mechanical arts. Some think
them a kind of dishonor. "But if my judgment be of any weight, the use
of History Mechanical is, of all others, the most radical and
fundamental towards natural philosophy." When the different arts are
known, the senses will furnish sufficient concrete material for the
information of the understanding. The record of the arts is of most use
because it exhibits things in motion, and leads more directly to
practice. "Upon this history, therefore, mechanical and illiberal as it
may seem (all fineness and daintiness set aside), the greatest diligence
must be bestowed." "Again, among the particular arts those are to be
preferred which exhibit, alter, and prepare natural bodies and
materials of things as agriculture, cooking, chemistry, dyeing; the
manufacture of glass, enamel, sugar, gunpowder, artificial fires, paper
and the like." Weaving, carpentry, architecture, manufacture of mills,
clocks, etc. follow. The purpose is not solely to bring the arts to
perfection, but all mechanical experiments should be as streams flowing
from all sides into the sea of philosophy.
Shortly after James I came to the throne in 1603, Bacon published his
_Advancement of Learning_. He continued in other writings, however, to
develop the organization of knowledge, and in 1623 summed up his plan in
the _De Augmentis Scientiarum_.
A recent writer (Pearson, 1900) has attempted to summarize Bacon's
classification of the different branches of learning. When one compares
this summary with an outline of the classification of knowledge made by
the French monk, Hugo of St. Victor, who stands midway between Isidore
of Seville (570-636) and Bacon, some points of resemblance are of course
obvious. Moreover, Hugo, like Bacon, insisted on the importance of not
being narrowly utilitarian. Men, he says, are often accustomed to value
knowledge not on its own account but for what it yields. Thus it is with
the arts of husbandry, weaving, painting, and the like, where skill is
considered absolutely vain, unless it results in some useful product.
If, however, we judged after this fashion of God's wisdom, then, no
doubt, the creation would be preferred to the Creator. But wisdom is
life, and the love of wisdom is the joy of life (_felicitas vitæ_).
Nevertheless, when we compare these classifications diligently, we find
very marked differences between Bacon's views and the medieval. The
weakest part of Hugo's classification is that which deals with natural
philosophy. _Physica_, he says, undertakes the investigation of the
causes of things in their effects, and of effects in their causes. It
deals with the explanation of earthquakes, tides, the virtues of plants,
the fierce instincts of wild animals, every species of stone, shrub, and
reptile. When we turn to his special work, however, on this branch of
knowledge, _Concerning Beasts and Other Things_, we find no attempt to
subdivide the field of _physica_, but a series of details in botany,
geology, zoölogy, and human anatomy, mostly arranged in dictionary form.
When we refer to Bacon's classification we find that Physics corresponds
to Hugo's _Physica_. It studies natural phenomena in relation to their
material causes. For this study, Natural History, according to Bacon,
supplies the facts. Let us glance, then, at his work on natural history,
and see how far he had advanced from the medieval toward the modern
conception of the sciences.
For purposes of scientific study he divided the phenomena of the
universe into (1) Celestial phenomena; (2) Atmosphere; (3) Globe; (4)
Substance of earth, air, fire, water; (5) Genera, species, etc. Great
scope is given to the natural history of man. The arts are classified as
_nature modified by man_. _History_ means, of course, descriptive
science.
_Bacon's Catalogue of Particular Histories by Titles (1620)_
1. History of the Heavenly Bodies; or Astronomical History.
2. History of the Configuration of the Heavens and the parts thereof
towards the Earth and the parts thereof; or Cosmographical
History.
3. History of Comets.
4. History of Fiery Meteors.
5. History of Lightnings, Thunderbolts, Thunders, and Coruscations.
6. History of Winds and Sudden Blasts and Undulations of the Air.
7. History of Rainbows.
8. History of Clouds, as they are seen above.
9. History of the Blue Expanse, of Twilight, of Mock-Suns,
Mock-Moons, Haloes, various colours of the Sun; and of every
variety in the aspect of the heavens caused by the medium.
10. History of Showers, Ordinary, Stormy, and Prodigious; also of
Waterspouts (as they are called); and the like.
11. History of Hail, Snow, Frost, Hoar-frost, Fog, Dew, and the like.
12. History of all other things that fall or descend from above, and
that are generated in the upper region.
13. History of Sounds in the upper region (if there be any), besides
Thunder.
14. History of Air as a whole, or in the Configuration of the World.
15. History of the Seasons or Temperatures of the Year, as well
according to the variations of Regions as according to accidents
of Times and Periods of Years; of Floods, Heats, Droughts, and the
like.
16. History of Earth and Sea; of the Shape and Compass of them, and
their Configurations compared with each other; and of their
broadening or narrowing; of Islands in the Sea; of Gulfs of the
Sea, and Salt Lakes within the Land; Isthmuses and Promontories.
17. History of the Motions (if any be) of the Globe of Earth and Sea;
and of the Experiments from which such motions may be collected.
18. History of the greater motions and Perturbations in Earth and Sea;
Earthquakes, Tremblings and Yawnings of the Earth, Islands newly
appearing; Floating Islands; Breakings off of Land by entrance of
the Sea, Encroachments and Inundations and contrariwise Recessions
of the Sea; Eruptions of Fire from the Earth; Sudden Eruptions of
Waters from the Earth; and the like.
19. Natural History of Geography; of Mountains, Vallies, Woods,
Plains, Sands, Marshes, Lakes, Rivers, Torrents, Springs, and
every variety of their course, and the like; leaving apart
Nations, Provinces, Cities, and such like matters pertaining to
Civil life.
20. History of Ebbs and Flows of the Sea; Currents, Undulations, and
other Motions of the Sea.
21. History of other Accidents of the Sea; its Saltness, its various
Colours, its Depth; also of Rocks, Mountains, and Vallies under
the Sea, and the like.
_Next come Histories of the Greater Masses_
22. History of Flame and of things Ignited.
23. History of Air, in Substance, not in the Configuration of the
World.
24. History of Water, in Substance, not in the Configuration of the
World.
25. History of the Earth and the diversity thereof, in Substance, not
in the Configuration of the World.
_Next come Histories of Species_
26. History of perfect Metals, Gold, Silver; and of the Mines, Veins,
Marcasites of the same; also of the Working in the Mines.
27. History of Quicksilver.
28. History of Fossils; as Vitriol, Sulphur, etc.
29. History of Gems; as the Diamond, the Ruby, etc.
30. History of Stones; as Marble, Touchstone, Flint, etc.
31. History of the Magnet.
32. History of Miscellaneous Bodies, which are neither entirely Fossil
nor Vegetable; as Salts, Amber, Ambergris, etc.
33. Chemical History of Metals and Minerals.
34. History of Plants, Trees, Shrubs, Herbs; and of their parts,
Roots, Stalks, Wood, Leaves, Flowers, Fruits, Seeds, Gums, etc.
35. Chemical History of Vegetables.
36. History of Fishes, and the Parts and Generation of them.
37. History of Birds, and the Parts and Generation of them.
38. History of Quadrupeds, and the Parts and Generation of them.
39. History of Serpents, Worms, Flies, and other insects; and of the
Parts and Generation of them.
40. Chemical History of the things which are taken by Animals.
_Next come Histories of Man_
41. History of the Figure and External Limbs of man, his Stature,
Frame, Countenance, and Features; and of the variety of the same
according to Races and Climates, or other smaller differences.
42. Physiognomical History of the same.
43. Anatomical History, or of the Internal Members of Man; and of the
variety of them, as it is found in the Natural Frame and
Structure, and not merely as regards Diseases and Accidents out of
the course of Nature.
44. History of the parts of Uniform Structure in Man; as Flesh, Bones,
Membranes, etc.
45. History of Humours in Man; Blood, Bile, Seed, etc.
46. History of Excrements; Spittle, Urine, Sweats, Stools, Hair of the
Head, Hairs of the Body, Whitlows, Nails, and the like.
47. History of Faculties; Attraction, Digestion, Retention,
Expulsion, Sanguification, Assimilation of Aliment into the
members, conversion of Blood and Flower of Blood into Spirit, etc.
48. History of Natural and Involuntary Motions; as Motion of the
Heart, the Pulses, Sneezing, Lungs, Erection, etc.
49. History of Motions partly Natural and Partly Violent; as of
Respiration, Cough, Urine, Stool, etc.
50. History of Voluntary Motions; as of the Instruments of
Articulation of Words; Motions of the Eyes, Tongue, Jaws, Hands,
Fingers; of Swallowing, etc.
51. History of Sleep and Dreams.
52. History of different habits of Body--Fat, Lean; of the Complexions
(as they call them), etc.
53. History of the Generation of Man.
54. History of Conception, Vivification, Gestation in the Womb, Birth,
etc.
55. History of the Food of Man; and of all things Eatable and
Drinkable; and of all Diet; and of the variety of the same
according to nations and smaller differences.
56. History of the Growth and Increase of the Body, in the whole and
in its parts.
57. History of the Course of Age; Infancy, Boyhood, Youth, Old Age; of
Length and Shortness of Life, and the like, according to nations
and lesser differences.
58. History of Life and Death.
59. History Medicinal of Diseases, and of the Symptoms and Signs of
them.
60. History Medicinal of the Treatment and Remedies and Cures of
Diseases.
61. History Medicinal of those things which preserve the Body and the
Health.
62. History Medicinal of those things which relate to the Form and
Comeliness of the Body.
63. History Medicinal of those things which alter the Body, and
pertain to Alterative Regimen.
64. History of Drugs.
65. History of Surgery.
66. Chemical History of Medicines.
67. History of Vision, and of things Visible.
68. History of Painting, Sculpture, Modelling, etc.
69. History of Hearing and Sound.
70. History of Music.
71. History of Smell and Smells.
72. History of Taste and Tastes.
73. History of Touch, and the objects of Touch.
74. History of Venus, as a species of Touch.
75. History of Bodily Pains, as species of Touch.
76. History of Pleasure and Pain in general.
77. History of the Affections; as Anger, Love, Shame, etc.
78. History of the Intellectual Faculties; Reflexion, Imagination,
Discourse, Memory, etc.
79. History of Natural Divinations.
80. History of Diagnostics, or Secret Natural Judgements.
81. History of Cookery, and of the arts thereto belonging, as of the
Butcher, Poulterer, etc.
82. History of Baking, and the Making of Bread, and the arts thereto
belonging, as of the Miller, etc.
83. History of Wine.
84. History of the Cellar and of different kinds of Drink.
85. History of Sweetmeats and Confections.
86. History of Honey.
87. History of Sugar.
88. History of the Dairy.
89. History of Baths and Ointments.
90. Miscellaneous History concerning the care of the body--as of
Barbers, Perfumers, etc.
91. History of the working of Gold, and the arts thereto belonging.
92. History of the manufactures of Wool, and the arts thereto
belonging.
93. History of the manufactures of Silk, and the arts thereto
belonging.
94. History of the manufactures of Flax, Hemp, Cotton, Hair, and
other kinds of Thread, and the arts thereto belonging.
95. History of manufactures of Feathers.
96. History of Weaving, and the arts thereto belonging.
97. History of Dyeing.
98. History of Leather-making, Tanning, and the arts thereto
belonging.
99. History of Ticking and Feathers.
100. History of working in Iron.
101. History of Stone-cutting.
102. History of the making of Bricks and Tiles.
103. History of Pottery.
104. History of Cements, etc.
105. History of working in Wood.
106. History of working in Lead.
107. History of Glass and all vitreous substances, and of Glass-making.
108. History of Architecture generally.
109. History of Waggons, Chariots, Litters, etc.
110. History of Printing, of Books, of Writing, of Sealing; of Ink,
Pen, Paper, Parchment, etc.
111. History of Wax.
112. History of Basket-making.
113. History of Mat-making, and of manufactures of Straw, Rushes, and
the like.
114. History of Washing, Scouring, etc.
115. History of Agriculture, Pasturage, Culture of Woods, etc.
116. History of Gardening.
117. History of Fishing.
118. History of Hunting and Fowling.
119. History of the Art of War, and of the arts thereto belonging, as
Armoury, Bow-making, Arrow-making, Musketry, Ordnance, Cross-bows,
Machines, etc.
120. History of the Art of Navigation, and of the crafts and arts
thereto belonging.
121. History of Athletics and Human Exercises of all kinds.
122. History of Horsemanship.
123. History of Games of all kinds.
124. History of Jugglers and Mountebanks.
125. Miscellaneous History of various Artificial Materials,--Enamel,
Porcelain, various cements, etc.
126. History of Salts.
127. Miscellaneous History of various Machines and Motions.
128. Miscellaneous History of Common Experiments which have not grown
into an Art.
_Histories must also be written of Pure Mathematics; though they are
rather observations than experiments_
129. History of the Natures and Powers of Numbers.
130. History of the Natures and Powers of Figures.
The fragment containing this catalogue (_Parasceve_--Day of Preparation)
was added to Bacon's work on method, _The New Logic_ (_Novum Organum_),
1620. Besides completing his survey and classification of the sciences
(_De Augmentis Scientiarum_), 1623, he published a few separate writings
on topics in the catalogue--_Winds_, _Life and Death_, _Tides_, etc. In
1627, a year after his death, appeared his much misunderstood work,
_Sylva Sylvarum_. He had found that the Latin word _sylva_ meant _stuff_
or _raw material_, as well as a _wood_, and called this final work
_Sylva Sylvarum_, which I would translate, "Jungle of Raw Material." He
himself referred to it as "an undigested heap of particulars"; yet he
was willing it should be published because "he preferred the good of men
to anything that might have relation to himself." In it, following his
catalogue, he fulfilled the promise made in 1620, of putting nature and
the arts to question. Some of the problems suggested for investigation
are: congealing of air, turning air into water, the secret nature of
flame, motion of gravity, production of cold, nourishing of young
creatures in the egg or womb, prolongation of life, the media of sound,
infectious diseases, accelerating and preventing putrefaction,
accelerating and staying growth, producing fruit without core or seed,
production of composts and helps for ground, flying in the air.
In the _New Atlantis_, a work of imagination, Bacon had represented as
already achieved for mankind some of the benefits he wished for:
artificial metals, various cements, excellent dyes, animals for
vivisection and medical experiment, instruments which generate heat
solely by motion, artificial precious stones, conveyance of sound for
great distances and in tortuous lines, new explosives. "We imitate,"
says the guide in the Utopian land, "also flights of birds; we have some
degree of flying in the air; we have ships and boats for going under
water." Bacon believed in honoring the great discoverers and inventors,
and advocated maintaining a calendar of inventions.
He was a fertile and stimulating thinker, and much of his great
influence arose from the comprehensiveness that led to his celebrated
classification of the sciences.
REFERENCES
Bacon's _Philosophical Works_, vol. IV, _Parasceve_, edited by R. L.
Ellis, J. Spedding, and D. D. Heath.
Karl Pearson, _Grammar of Science_.
J. A. Thomson, _Introduction to Science_.
CHAPTER VI
SCIENTIFIC METHOD--GILBERT, GALILEO, HARVEY, DESCARTES
The previous chapter has given some indication of the range of the
material which was demanding scientific investigation at the end of the
sixteenth and the beginning of the seventeenth century. The same period
witnessed a conscious development of the method, or methods, of
investigation. As we have seen, Bacon wrote in 1620 a considerable work,
_The New Logic_ (_Novum Organum_), so called to distinguish it from the
traditional deductive logic. It aimed to furnish the organ or
instrument, to indicate the correct mental procedure, to be employed in
the discovery of natural law. Some seventeen years later, the
illustrious Frenchman René Descartes (1596-1650) published his
_Discourse on the Method of rightly conducting the Reason and seeking
Truth in the Sciences_. Both of these philosophers illustrated by their
own investigations the efficiency of the methods which they advocated.
[Illustration: _Painting by A. Ackland Hunt_
DR. GILBERT SHOWING HIS ELECTRICAL EXPERIMENTS TO QUEEN ELIZABETH AND
HER COURT]
Before 1620, however, the experimental method had already yielded
brilliant results in the hands of other scientists. We pass over
Leonardo da Vinci and many others in Italy and elsewhere, whose names
should be mentioned if we were tracing this method to its origin. By
1600 William Gilbert (1540-1603), physician to Queen Elizabeth, before
whom, as a picture in his birthplace illustrates, he was called to
demonstrate his discoveries, had published his work on the Magnet, the
outcome of about eighteen years of critical research. He may be
considered the founder of electrical science. Galileo, who discovered
the fundamental principles of dynamics and thus laid the basis of modern
physical science, although he did not publish his most important work
till 1638, had even before the close of the sixteenth century prepared
the way for the announcement of his principles by years of strict
experiment. By the year 1616, William Harvey (1578-1657), physician at
the court of James I, and, later, of Charles I, had, as the first modern
experimental physiologist, gained important results through his study of
the circulation of the blood.
It is not without significance that both Gilbert and Harvey had spent
years in Italy, where, as we have implied, the experimental method of
scientific research was early developed. Harvey was at Padua (1598-1602)
within the time of Galileo's popular professoriate, and may well have
been inspired by the physicist to explain on dynamical principles the
flow of blood through arteries and veins. This conjecture is the more
probable, since Galileo, like Harvey and Gilbert, had been trained in
the study of medicine. Bacon in turn had in his youth learned something
of the experimental method on the Continent of Europe, and, later, was
well aware of the studies of Gilbert and Galileo, as well as of Harvey,
who was indeed his personal physician.
Although these facts seem to indicate that method may be transmitted in
a nation or a profession, or through personal association, there still
remains some doubt as to whether anything so intimate as the mental
procedure involved in invention and in the discovery of truth can be
successfully imparted by instruction. The individuality of the man of
genius engaged in investigation must remain a factor difficult to
analyze. Bacon, whose purpose was to hasten man's empire over nature
through increasing the number of inventions and discoveries, recognized
that the method he illustrated is not the sole method of scientific
investigation. In fact, he definitely states that the method set forth
in the _Novum Organum_ is not original, or perfect, or indispensable. He
was aware that his method tended to the ignoring of genius and to the
putting of intelligences on one level. He knew that, although it is
desirable for the investigator to free his mind from prepossessions, and
to avoid premature generalizations, interpretation is the true and
natural work of the mind when free from impediments, and that the
conjecture of the man of genius must at times anticipate the slow
process of painful induction. As we shall see in the nineteenth chapter,
the psychology of to-day does not know enough about the workings of the
mind to prescribe a fixed mental attitude for the investigator.
Nevertheless, Bacon was not wrong in pointing out the virtues of a
method which he and many others turned to good account. Let us first
glance, however, at the activities of those scientists who preceded
Bacon in the employment of the experimental method.
Gilbert relied, in his investigations, on oft-repeated and verifiable
experiments, as can be seen from his work _De Magnete_. He directs the
experimenter, for example, to take a piece of loadstone of convenient
size and turn it on a lathe to the form of a ball. It then may be
called a _terrella_, or earthkin. Place on it a piece of iron wire. The
ends of the wire move round its middle point and suddenly come to a
standstill. Mark with chalk the line along which the wire lies still and
sticks. Then move the wire to other spots on the _terrella_ and repeat
your procedure. The lines thus marked, if produced, will form meridians,
all coming together at the poles. Again, place the magnet in a wooden
vessel, and then set the vessel afloat in a tub or cistern of still
water. The north pole of the stone will seek approximately the direction
of the south pole of the earth, etc. It was on the basis of scores of
experiments of this sort, carried on from about 1582 till 1600, that
Gilbert felt justified in concluding that the terrestrial globe is a
magnet. This theory has since that time been abundantly confirmed by
navigators. The full title of his book is _Concerning the Magnet and
Magnetic Bodies, and concerning the Great Magnet the Earth: A New
Natural History (Physiologia) demonstrated by many Arguments and
Experiments_. It does not detract from the credit of Gilbert's result to
state that his initial purpose was not to discover the nature of
magnetism or electricity, but to determine the true substance of the
earth, the innermost constitution of the globe. He was fully conscious
of his own method and speaks with scorn of certain writers who, having
made no magnetical experiments, constructed ratiocinations on the basis
of mere opinions and old-womanishly dreamed the things that were not.
Galileo (1564-1642) even as a child displayed something of the
inventor's ingenuity, and when he was nineteen, shortly after the
beginning of Gilbert's experiments, his keen perception for the
phenomena of motion led to his making a discovery of great scientific
moment. He observed a lamp swinging by a long chain in the cathedral of
his native city of Pisa, and noticed that, no matter how much the range
of the oscillations might vary, their times were constant. He verified
his first impressions by counting his pulse, the only available
timepiece. Later he invented simple pendulum devices for timing the
pulse of patients, and even made some advances in applying his discovery
in the construction of pendulum clocks.
b
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In 1589 he was appointed professor of mathematics in the University of
Pisa, and within a year or two established through experiment the
foundations of the science of dynamics. As early as 1590 he put on
record, in a Latin treatise _Concerning Motion_ (_De Motu_), his dissent
from the theories of Aristotle in reference to moving bodies, confuting
the Philosopher both by reason and ocular demonstration. Aristotle had
held that two moving bodies of the same sort and in the same medium have
velocities in proportion to their weights. If a moving body, whose
weight is represented by _b_, be carried through the line _c--e_ which
is divided in the point _d_, if, also, the moving body is divided
according to the same proportion as line _c--e_ is in the point _d_, it
is manifest that in the time taken to carry the whole body through
_c--e_, the part will be moved through _c--d_. Galileo said that it is
as clear as daylight that this view is ridiculous, for who would
believe that when two lead spheres are dropped from a great height, the
one being a hundred times heavier than the other, if the larger took an
hour to reach the earth, the smaller would take a hundred hours? Or,
that if from a high tower two stones, one twice the weight of the other,
should be pushed out at the same moment, the larger would strike the
ground while the smaller was still midway? His biography tells that
Galileo in the presence of professors and students dropped bodies of
different weights from the height of the Leaning Tower of Pisa to
demonstrate the truth of his views. If allowance be made for the
friction of the air, all bodies fall from the same height in equal
times: the final velocities are proportional to the times; the spaces
passed through are proportional to the squares of the times. The
experimental basis of the last two statements was furnished by means of
an inclined plane, down a smooth groove in which a bronze ball was
allowed to pass, the time being ascertained by means of an improvised
water-clock.
Galileo's mature views on dynamics received expression in a work
published in 1638, _Mathematical Discourses and Demonstrations
concerning Two New Sciences relating to Mechanics and Local Movements_.
It treats of cohesion and resistance to fracture (strength of
materials), and uniform, accelerated, and projectile motion (dynamics).
The discussion is in conversation form. The opening sentence shows
Galileo's tendency to base theory on the empirical. It might be freely
translated thus: "Large scope for intellectual speculation, I should
think, would be afforded, gentlemen, by frequent visits to your famous
Venetian Dockyard (_arsenale_), especially that part where mechanics are
in demand; seeing that there every sort of instrument and machine is put
to use by numbers of workmen, among whom, taught both by tradition and
their own observation, there must be some very skillful and also able to
talk." The view of the shipbuilders, that a large galley before being
set afloat is in greater danger of breaking under its own weight than a
small galley, is the starting-point of this most important of Galileo's
contributions to science.
Vesalius (1514-1564) had in his work on the structure of the human body
(_De Humani Corporis Fabrica_, 1543) shaken the authority of Galen's
anatomy; it remained for Harvey on the basis of the new anatomy to
improve upon the Greek physician's experimental physiology. Harvey
professed to learn and teach anatomy, not from books, but from
dissections, not from the dogmas of the philosophers, but from the
fabric of nature.
There have come down to us notes of his lectures on anatomy delivered
first in 1616. A brief extract will show that even at that date he had
already formulated a theory of the circulation of the blood:--
"[Illustration: WH monogram][1] By the structure of the heart it appears
that the blood is continually transfused through the lungs to the
aorta--as by the two clacks of a water-ram for raising water.
"It is shown by ligature that there is continuous motion of the blood
from arteries to veins.
"Whence Δ it is demonstrated that there is a continuous motion of the
blood in a circle, affected by the beat of the heart."
It was not till 1628 that Harvey published his _Anatomical Disquisition
on the Motion of the Heart and Blood in Animals_. It gives the
experimental basis of his conclusions. If a live snake be laid open, the
heart will be seen pulsating and propelling its contents. Compress the
large vein entering the heart, and the part intervening between the
point of constriction and the heart becomes empty and the organ pales
and shrinks. Remove the pressure, and the size and color of the heart
are restored. Now compress the artery leading from the organ, and the
part between the heart and the point of pressure, and the heart itself,
become distended and take on a deep purple color. The course of the
blood is evidently from the vena cava through the heart to the aorta.
Harvey in his investigations made use of many species of animals--at
least eighty-seven.
It was believed by some, before Harvey's demonstrations, that the
arteries were hollow pipes carrying air from the lungs throughout the
body, although Galen had shown by cutting a dog's trachea, inflating the
lungs and tying the trachea, that the lungs were in an enclosing sack
which retained the air. Harvey, following Galen, held that the pulmonary
artery, carrying blood to the lungs from the right side of the heart,
and the pulmonary veins, carrying blood from the lungs to the left side
of the heart, intercommunicate in the hidden porosities of the lungs and
through minute inosculations.
In man the vena cava carries the blood to the right side of the heart,
the pulmonary artery inosculates with the pulmonary veins, which convey
it to the left side of the heart. This muscular pump drives it into the
aorta. It still remains to be shown that in the limbs the blood passes
from the arteries to the veins. Bandage the arm so tightly that no pulse
is felt at the wrist. The hand appears at first natural, and then grows
cold. Loose the bandage sufficiently to restore the pulse. The hand and
forearm become suffused and swollen. In the first place the supply of
blood from the deep-lying arteries is cut off. In the second case the
blood returning by the superficial veins is dammed back. In the limbs as
in the lungs the blood passes from artery to vein by anastomoses and
porosities. All these arteries have their source in the aorta; all these
veins pour their stream ultimately into the vena cava. The veins have
valves, which prevent the blood flowing except toward the heart. Again,
the veins and arteries form a connected system; for through either a
vein or an artery all the blood may be drained off. The arguments by
which Harvey supported his view were various. The opening clause of his
first chapter, "When I first gave my mind to vivisection as a means of
discovering the motions and uses of the heart," throws a strong light on
his special method of experimental investigation.
Bacon, stimulated by what he called _philanthropia_, always aimed, as we
have seen, to establish man's control over nature. But all power of a
high order depends on an understanding of the essential character, or
law, of heat, light, sound, gravity, and the like. Nothing short of a
knowledge of the underlying nature of phenomena can give science
advantage over chance in hitting upon useful discoveries and inventions.
It is, therefore, natural to find him applying his method of
induction--his special method of true induction--to the investigation of
heat.
In the first place, let there be mustered, without premature
speculation, all the instances in which heat is manifested--flame,
lightning, sun's rays, quicklime sprinkled with water, damp hay, animal
heat, hot liquids, bodies subjected to friction. Add to these, instances
in which heat seems to be absent, as moon's rays, sun's rays on
mountains, oblique rays in the polar circle. Try the experiment of
concentrating on a thermoscope, by means of a burning-glass, the moon's
rays. Try with the burning-glass to concentrate heat from hot iron, from
common flame, from boiling water. Try a concave glass with the sun's
rays to see whether a diminution of heat results. Then make record of
other instances, in which heat is found in varying degrees. For example,
an anvil grows hot under the hammer. A thin plate of metal under
continuous blows might grow red like ignited iron. Let this be tried as
an experiment.
After the presentation of these instances induction itself must be set
to work to find out what factor is ever present in the positive
instances, what factor is ever wanting in the negative instances, what
factor always varies in the instances which show variation. According to
Bacon it is in the process of exclusion that the foundations of true
induction are laid. We can be certain, for example, that the essential
nature of heat does not consist in light and brightness, since it is
present in boiling water and absent in the moon's rays.
The induction, however, is not complete till something positive is
established. At this point in the investigation it is permissible to
venture an hypothesis in reference to the essential character of heat.
From a survey of the instances, all and each, it appears that the nature
of which heat is a particular case is motion. This is suggested by
flame, simmering liquids, the excitement of heat by motion, the
extinction of fire by compression, etc. Motion is the genus of which
heat is the species. Heat itself, its essence, is motion and nothing
else.
It remains to establish its specific differences. This accomplished, we
arrive at the definition: Heat is a motion, expansive, restrained, and
acting in its strife upon the smaller particles of bodies. Bacon,
glancing toward the application of this discovery, adds: "_If in any
natural body you can excite a dilating or expanding motion, and can so
repress this motion and turn it back upon itself, that the dilation
shall not proceed equally, but have its way in one part and be
counteracted in another, you will undoubtedly generate heat._" The
reader will recall that Bacon looked for the invention of instruments
that would generate heat solely by motion.
Descartes was a philosopher and mathematician. In his _Discourse on
Method_ and his _Rules for the Direction of the Mind_ (1628) he laid
emphasis on deduction rather than on induction. In the subordination of
particulars to general principles he experienced a satisfaction akin to
the sense of beauty or the joy of artistic production. He speaks
enthusiastically of that pleasure which one feels in truth, and which
in this world is about the only pure and unmixed happiness.
At the same time he shared Bacon's distrust of the Aristotelian logic
and maintained that ordinary dialectic is valueless for those who desire
to investigate the truth of things. There is need of a method for
finding out the truth. He compares himself to a smith forced to begin at
the beginning by fashioning tools with which to work.
In his method of discovery he determined to accept nothing as true that
he did not clearly recognize to be so. He stood against assumptions, and
insisted on rigid proof. Trust only what is completely known. Attain a
certitude equal to that of arithmetic and geometry. This attitude of
strict criticism is characteristic of the scientific mind.
Again, Descartes was bent on analyzing each difficulty in order to solve
it; to neglect no intermediate steps in the deduction, but to make the
enumeration of details adequate and methodical. Preserve a certain
order; do not attempt to jump from the ground to the gable, but rise
gradually from what is simple and easily understood.
Descartes' interest was not in the several branches of mathematics;
rather he wished to establish a universal mathematics, a general science
relating to order and measurement. He considered all physical nature,
including the human body, as a mechanism, capable of explanation on
mathematical principles. But his immediate interest lay in numerical
relationships and geometrical proportions.
Recognizing that the understanding was dependent on the other powers of
the mind, Descartes resorted in his mathematical demonstrations to the
use of lines, because he could find no method, as he says, more simple
or more capable of appealing to the imagination and senses. He
considered, however, that in order to bear the relationships in memory
or to embrace several at once, it was essential to explain them by
certain formulæ, the shorter the better. And for this purpose it was
requisite to borrow all that was best in geometrical analysis and
algebra, and to correct the errors of one by the other.
Descartes was above all a mathematician, and as such he may be regarded
as a forerunner of Newton and other scientists; at the same time he
developed an exact scientific method, which he believed applicable to
all departments of human thought. "Those long chains of reasoning," he
says, "quite simple and easy, which geometers are wont to employ in the
accomplishment of their most difficult demonstrations, led me to think
that everything which might fall under the cognizance of the human mind
might be connected together in the same manner, and that, provided only
one should take care not to receive anything as true which was not so,
and if one were always careful to preserve the order necessary for
deducing one truth from another, there would be none so remote at which
he might not at last arrive, or so concealed which he might not
discover."
REFERENCES
Francis Bacon, _Philosophical Works_ (Ellis and Spedding edition), vol.
IV, Novum Organum.
J. J. Fahie, _Galileo; His Life and Work_.
Galileo, _Two New Sciences_; translated by Henry Crew and Alphonse De
Salvio.
William Gilbert, _On the Loadstone_; translated by P. F. Mottelay.
William Harvey, _An Anatomical Disquisition on the Motion of the Heart
and Blood in Animals_.
T. H. Huxley, _Method and Results_.
D'Arcy Power, _William Harvey_ (in _Masters of Medicine_).
FOOTNOTES:
[1] This is Harvey's monogram, which he used in his notes to mark any
original observation.
CHAPTER VII
SCIENCE AS MEASUREMENT--TYCHO BRAHE, KEPLER, BOYLE
Considering the value for clearness of thought of counting, measuring
and weighing, it is not surprising to find that in the seventeenth
century, and even at the end of the sixteenth, the advance of the
sciences was accompanied by increased exactness of measurement and by
the invention of instruments of precision. The improvement of the simple
microscope, the invention of the compound microscope, of the telescope,
the micrometer, the barometer, the thermoscope, the thermometer, the
pendulum clock, the improvement of the mural quadrant, sextant, spheres,
astrolabes, belong to this period.
Measuring is a sort of counting, and weighing a form of measuring. We
may count disparate things whether like or unlike. When we measure or
weigh we apply a standard and count the times that the unit--cubit,
pound, hour--is found to repeat itself. We apply our measure to uniform
extension, meting out the waters by fathoms or space by the sun's
diameter, and even subject time to arbitrary divisions. The human mind
has been developed through contact with the multiplicity of physical
objects, and we find it impossible to think clearly and scientifically
about our environment without dividing, weighing, measuring, counting.
In measuring time we cannot rely on our inward impressions; we even
criticize these impressions and speak of time as going slowly or
quickly. We are compelled in the interests of accuracy to provide an
objective standard in the clock, or the revolving earth, or some other
measurable thing. Similarly with weight and heat; we cannot rely on the
subjective impression, but must devise apparatus to record by a
measurable movement the amount of the pressure or the degree of
temperature.
"God ordered all things by measure, number, and weight." The scientific
mind does not rest satisfied till it is able to see phenomena in their
number relationships. Scientific thought is in this sense Pythagorean,
that it inquires in reference to quantity and proportion.
As implied in a previous chapter, number relations are not clearly
grasped by primitive races. Many primitive languages have no words for
numerals higher than five. That fact does not imply that these races do
not know the difference between large and small numbers, but precision
grows with civilization, with commercial pursuits, and other activities,
such as the practice of medicine, to which the use of weights and
measures is essential. Scientific accuracy is dependent on words and
other means of numerical expression. From the use of fingers and toes, a
rude score or tally, knots on a string, or a simple abacus, the race
advances to greater refinement of numerical expression and the
employment of more and more accurate apparatus.
One of the greatest contributors to this advance was the celebrated
Danish astronomer, Tycho Brahe (1546-1601). Before 1597 he had completed
his great mural quadrant at the observatory of Uraniborg. He called it
with characteristic vanity the Tichonic quadrant. It consisted of a
graduated arc of solid polished brass five inches broad, two inches
thick, and with a radius of about six and three quarters feet. Each
degree was divided into minutes, and each minute into six parts. Each of
these parts was then subdivided into ten seconds, which were indicated
by dots arranged in transverse oblique lines on the width of brass.
[Illustration: THE TICHONIC QUADRANT]
The arc was attached in the observation room to a wall running exactly
north, and so secured with screws (_firmissimis cochleis_) that no force
could move it. With its concavity toward the southern sky it was closely
comparable, though reverse, to the celestial meridian throughout its
length from horizon to zenith. The south wall, above the point where the
radii of the quadrant met, was pierced by a cylinder of gilded brass
placed in a rectangular opening, which could be opened or closed from
the outside. The observation was made through one of two sights that
were attached to the graduated arc and could be moved from point to
point on it. In the sights were parallel slits, right, left, upper,
lower. If the altitude and the transit through the meridian were to be
taken at the same time the four directions were to be followed. It was
the practice for the student making the observation to read off the
number of degrees, minutes, etc., of the angle at which the altitude or
transit was observed, so that it might be recorded by a second student.
A third took the time from two clock dials when the observer gave the
signal, and the exact moment of observation was also recorded by
student number two. The clocks recorded minutes and the smaller
divisions of time; great care, however, was required to obtain good
results from them. There were four clocks in the observatory, of which
the largest had three wheels, one wheel of pure solid brass having
twelve hundred teeth and a diameter of two cubits.
Lest any space on the wall should lie empty a number of paintings were
added: Tycho himself in an easy attitude seated at a table and directing
from a book the work of his students. Over his head is an automatic
celestial globe invented by Tycho and constructed at his own expense in
1590. Over the globe is a part of Tycho's library. On either side are
represented as hanging small pictures of Tycho's patron, Frederick II of
Denmark (d. 1588) and Queen Sophia. Then other instruments and rooms of
the observatory are pictured; Tycho's students, of whom there were
always at least six or eight, not to mention younger pupils. There
appears also his great brass globe six feet in diameter. Then there is
pictured Tycho's chemical laboratory, on which he has expended much
money. Finally comes one of Tycho's hunting dogs--very faithful and
sagacious; he serves here as a hieroglyph of his master's nobility as
well as of sagacity and fidelity. The expert architect and the two
artists who assisted Tycho are delineated in the landscape and even in
the setting sun in the top-most part of the painting, and in the
decoration above.
The principal use of this largest quadrant was the determination of the
angle of elevation of the stars within the sixth part of a minute, the
collineation being made by means of one of the sights, the parallel
horizontal slits in which were aligned with the corresponding parts of
the circumference of the cylinder. The altitude was recorded according
to the position of the sight attached to the graduated arc.
Tycho Brahe had a great reverence for Copernicus, but he did not accept
his planetary system; and he felt that advance in astronomy depended on
painstaking observation. For over twenty years under the kings of
Denmark he had good opportunities for pursuing his investigation. The
island of Hven became his property. A thoroughly equipped observatory
was provided, including printing-press and workshops for the
construction of apparatus. As already implied, capable assistants were
at the astronomer's command. In 1598, after having left Denmark, Tycho
in a splendid illustrated book (_Astronomiæ Instauratæ Mechanica_) gave
an account of this astronomical paradise on the Insula Venusia as he at
times called it. The book, prepared for the hands of princes, contains
about twenty full-page colored illustrations of astronomical instruments
(including, of course, the mural quadrant), of the exterior of the
observatory of Uraniborg, etc. The author had a consciousness of his own
worth, and deserves the name Tycho the Magnificent. The results that
he obtained were not unworthy of the apparatus employed in his
observations, and before he died at Prague in 1601, Tycho Brahe had
consigned to the worthiest hands the painstaking record of his labors.
Johann Kepler (1571-1630) had been called, as the astronomer's
assistant, to the Bohemian capital in 1600 and in a few months fell heir
to Tycho's data in reference to 777 stars, which he made the basis of
the Rudolphine tables of 1627. Kepler's genius was complementary to that
of his predecessor. He was gifted with an imagination to turn
observations to account. His astronomy did not rest in mere description,
but sought the physical explanation. He had the artist's feeling for the
beauty and harmony, which he divined before he demonstrated, in the
number relations of the planetary movements. After special studies of
Mars based on Tycho's data, he set forth in 1609 (_Astronomia Nova_) (1)
that every planet moves in an ellipse of which the sun occupies one
focus, and (2) that the area swept by the radius vector from the planet
to the sun is proportional to the time. Luckily for the success of his
investigation the planet on which he had concentrated his attention is
the one of all the planets then known, the orbit of which most widely
differs from a circle. In a later work (_Harmonica Mundi_, 1619) the
title of which, the _Harmonics of the Universe_, proclaimed his
inclination to Pythagorean views, he demonstrated (3) that the square of
the periodic time of any planet is proportional to the cube of its mean
distance from the sun.
Kepler's studies were facilitated by the invention, in 1614 by John
Napier, of logarithms, which have been said, by abridging tedious
calculations, to double the life of an astronomer. About the same time
Kepler in purchasing some wine was struck by the rough-and-ready method
used by the merchant to determine the capacity of the wine-vessels. He
applied himself for a few days to the problems of mensuration involved,
and in 1615 published his treatise (_Stereometria Doliorum_) on the
cubical contents of casks (or wine-jars), a source of inspiration to all
later writers on the accurate determination of the volume of solids. He
helped other scientists and was himself richly helped. As early as 1610
there had been presented to him a means of precision of the first
importance to the progress of astronomy, namely, a Galilean telescope.
The early history of telescopes shows that the effect of combining two
lenses was understood by scientists long before any particular use was
made of this knowledge; and that those who are accredited with
introducing perspective glasses to the public hit by accident upon the
invention. Priority was claimed by two firms of spectacle-makers in
Middelburg, Holland, namely, Zacharias, miscalled Jansen, and
Lippershey. Galileo heard of the contrivance in July, 1609, and soon
furnished so powerful an instrument of discovery that things seen
through it appeared more than thirty times nearer and almost a thousand
times larger than when seen by the naked eye. He was able to make out
the mountains in the moon, the satellites of Jupiter in rotation, the
spots on the revolving sun; but his telescope afforded only an imperfect
view of Saturn. Of course these facts, published in 1610 (_Sidereus
Nuncius_), strengthened his advocacy of the Copernican system. Galileo
laughingly wrote Kepler that the professors of philosophy were afraid to
look through his telescope lest they should fall into heresy. The German
astronomer, who had years before written on the optics of astronomy,
now (1611) produced his _Dioptrice_, the first satisfactory statement of
the theory of the telescope.
About 1639 Gascoigne, a young Englishman, invented the micrometer, which
enables an observer to adjust a telescope with very great precision.
Before the invention of the micrometer exactitude was impossible,
because the adjustment of the instrument depended on the discrimination
of the naked eye. The micrometer was a further advance in exact
measurement. Gascoigne's determinations of, for example, the diameter of
the sun, bear comparison with the findings of even recent astronomical
science.
The history of the microscope is closely connected with that of the
telescope. In the first half of the seventeenth century the simple
microscope came into use. It was developed from the convex lens, which,
as we have seen in a previous chapter, had been known for centuries, if
not from remote antiquity. With the simple microscope Leeuwenhoek before
1673 had studied the structure of minute animal organisms and ten years
later had even obtained sight of bacteria. Very early in the same
century Zacharias had presented Prince Maurice, the commander of the
Dutch forces, and the Archduke Albert, governor of Holland, with
compound microscopes. Kircher (1601-1680) made use of an instrument that
represented microscopic forms as one thousand times larger than their
actual size, and by means of the compound microscope Malpighi was able
in 1661 to see blood flowing from the minute arteries to the minute
veins on the lung and on the distended bladder of the live frog. The
Italian microscopist thus, among his many achievements, verified by
observation what Harvey in 1628 had argued must take place.
In this same epoch apparatus of precision developed in other fields.
Weight clocks had been in use as time-measurers since the thirteenth
century, but they were, as we have seen, difficult to control and
otherwise unreliable. Even in the seventeenth century scientists in
their experiments preferred some form of water-clock. In 1636 Galileo,
in a letter, mentioned the feasibility of constructing a pendulum clock,
and in 1641 he dictated a description of the projected apparatus to his
son Vincenzo and to his disciple Viviani. He himself was then blind, and
he died the following year. His instructions were never carried into
effect. However, in 1657 Christian Huygens applied the pendulum to
weight clocks of the old stamp. In 1674 he gave directions for the
manufacture of a watch, the movement of which was driven by a spring.
Galileo, to whom the advance in exact science is so largely indebted,
must also be credited with the first apparatus for the measurement of
temperatures. This was invented before 1603 and consisted of a glass
bulb with a long stem of the thickness of a straw. The bulb was first
heated and the stem placed in water. The point at which the water, which
rose in the tube, might stand was an indication of the temperature. In
1631 Jean Rey just inverted this contrivance, filling the bulb with
water. Of course these thermoscopes would register the effect of varying
pressures as well as temperatures, and they soon made way for the
thermometer and the barometer. Before 1641 a true thermometer was
constructed by sealing the top of the tube after driving out the air by
heat. Spirits of wine were used in place of water. Mercury was not
employed till 1670.
Descartes and Galileo had brought under criticism the ancient idea that
nature abhors a vacuum. They knew that the _horror vacui_ was not
sufficient to raise water in a pump more than about thirty-three feet.
They had also known that air has weight, a fact which soon served to
explain the so-called force of suction. Galileo's associate Torricelli
reasoned that if the pressure of the air was sufficient to support a
column of water thirty-three feet in height, it would support a column
of mercury of equal weight. Accordingly in 1643 he made the experiment
of filling with mercury a glass tube four feet long closed at the upper
end, and then opening the lower end in a basin of mercury. The mercury
in the tube sank until its level was about thirty inches above that of
the mercury in the basin, leaving a vacuum in the upper part of the
tube. As the specific gravity of mercury is 13, Torricelli knew that his
supposition had been correct and that the column of mercury in the tube
and the column of water in the pump were owing to the pressure or weight
of the air.
Pascal thought that this pressure would be less at a high altitude. His
supposition was tested on a church steeple at Paris, and, later, on the
Puy de Dôme, a mountain in Auvergne. In the latter case a difference of
three inches in the column of mercury was shown at the summit and base
of the ascent. Later Pascal experimented with the siphon and succeeded
in explaining it on the principle of atmospheric pressure.
Torricelli in the space at the top of his barometer (pressure-gauge) had
produced what is called a Torricellian vacuum. Otto von Guericke, a
burgomaster of Magdeburg, who had traveled in France and Italy,
succeeded in constructing an air-pump by means of which air might be
exhausted from a vessel. Some of his results became widely known in
1657, though his works were not published till 1673.
Robert Boyle (1626-1691), born at Castle Lismore in Ireland, was the
seventh son and fourteenth child of the distinguished first Earl of
Cork. He was early acquainted with these various experiments in
reference to the air, as well as with Descartes' theory that air
is nothing but a congeries or heap of small, and, for the most
part, flexible particles. In 1659 he wrote his _New Experiments
Physico-Mechanical touching the Spring of the Air_. Instead of _spring_,
he at times used the word _elater_ (ἐλατὴρ). In this treatise he
describes experiments with the improved air-pump constructed at his
suggestion by his assistant, Robert Hooke.
One of Boyle's critics, a professor at Louvain, while admitting that air
had weight and elasticity, denied that these were sufficient to account
for the results ascribed to them. Boyle thereupon published a _Defence
of the Doctrine touching the Spring and Weight of the Air_. He felt able
to prove that the elasticity of the air could under circumstances do far
more than sustain twenty-nine or thirty inches of mercury. In support of
his view he cited a recent experiment.
He had taken a piece of strong glass tubing fully twelve feet in length.
(The experiment was made by a well-lighted staircase, the tube being
suspended by strings.) The glass was heated more than a foot from the
lower end, and bent so that the shorter leg of twelve inches was
parallel with the longer. The former was hermetically sealed at the top
and marked off in forty-eight quarter-inch spaces. Into the opening of
the longer leg, also graduated, mercury was poured. At first only enough
was introduced to fill the arch, or bent part of the tube below the
graduated legs. The tube was then inclined so that the air might pass
from one leg to the other, and equality of pressure at the start be
assured. Then more mercury was introduced and every time that the air in
the shorter leg was compressed a half or a quarter of an inch, a record
was made of the height of the mercury in the long leg of the tube. Boyle
reasoned that the compressed air was sustaining the pressure of the
column of mercury in the long leg _plus_ the pressure of the atmosphere
at the tube's opening, equivalent to 29-2/16 inches of mercury. Some of
the results were as follows: When the air in the short tube was
compressed from 12 to 3 inches, it was under a pressure of 117-9/16
inches of mercury; when compressed to 4 it was under pressure of
87-15/16 inches of mercury; when compressed to 6, 58-13/16; to 9,
39-5/8. Of course, when at the beginning of the experiment there were 12
inches of air in the short tube, it was under the pressure of the
atmosphere, equal to that of 29-2/16 inches of mercury. Boyle with
characteristic caution was not inclined to draw too general a conclusion
from his experiment. However, it was evident, making allowance for some
slight irregularity in the experimental results, that air reduced under
pressure to one half its original volume, doubles its resistance; and
that if it is further reduced to one half,--for example, from six to
three inches,--it has four times the resistance of common air. In fact,
Boyle had sustained the hypothesis that supposes the pressures and
expansions to be in reciprocal proportions.
REFERENCES
Sir Robert S. Ball, _Great Astronomers_.
Robert Boyle, _Works_ (edited by Thomas Birch).
Sir David Brewster, _Martyrs of Science_.
J. L. E. Dreyer, _Tycho Brahe_.
Sir Oliver Lodge, _Pioneers of Science_.
Flora Masson, _Robert Boyle; a Biography_.
CHAPTER VIII
COÖPERATION IN SCIENCE--THE ROYAL SOCIETY
The period from 1637 to 1687 affords a good illustration of the value
for the progress of science of the coöperation in the pursuit of truth
of men of different creeds, nationalities, vocations, and social ranks.
At, or even before, the beginning of that period the need of coöperation
was indicated by the activities of two men of pronouncedly social
temperament and interests, namely, the French Minim father, Mersenne,
and the Protestant Prussian merchant, Samuel Hartlib.
Mersenne was a stimulating and indefatigable correspondent. His letters
to Galileo, Jean Rey, Hobbes, Descartes, Gassendi, not to mention other
scientists and philosophers, constitute an encyclopedia of the learning
of the time. A mathematician and experimenter himself, he had a genius
for eliciting discussion and research by means of adroit questions.
Through him Descartes was drawn into debate with Hobbes, and with
Gassendi, a champion of the experimental method. Through him the
discoveries of Harvey, Galileo, and Torricelli, as well as of many
others, became widely known. His letters, in the dearth of scientific
associations and the absence of scientific periodicals, served as a
general news agency among the learned of his time. It is not surprising
that a coterie gathered about him at Paris. Hobbes spent months in
daily intercourse with this group of scientists in the winter of
1636-37.
Hartlib, though he scarcely takes rank with Mersenne as a scientist, was
no less influential. Of a generous and philanthropic disposition, he
repeatedly impoverished himself in the cause of human betterment. His
chief reliance was on education and improved methods of husbandry, but
he resembled Horace Greeley in his hospitality to any project for the
public welfare.
One of Hartlib's chief hopes for the regeneration of England, if not of
the whole world, rested on the teachings of the educational reformer
Comenius, a bishop of the Moravian Brethren. In 1637, Comenius having
shown himself rather reluctant to put his most cherished plans before
the public, his zealous disciple precipitated matters, and on his own
responsibility, and unknown to Comenius, issued from his library at
Oxford _Preludes to the Endeavors of Comenius_. Besides Hartlib's
preface it contained a treatise by the great educator on a _Seminary of
Christian Pansophy_, a method of imparting an encyclopedic knowledge of
the sciences and arts.
The two friends were followers of the Baconian philosophy. They were
influenced, as many others of the time, by the _New Atlantis_, which
went through ten editions between 1627 and 1670, and which outlined a
plan for an endowed college with thirty-six Fellows divided into
groups--what would be called to-day a university of research endowed by
the State. It is not surprising to find Comenius (who in his student
days had been under the influence of Alsted, author of an encyclopedia
on Baconian lines) speaking in 1638 on the need of a collegiate society
for carrying on the educational work that he himself had at heart.
In 1641 Hartlib published a work of fiction in the manner of the _New
Atlantis_, and dedicated it to the Long Parliament. In the same year he
urged Comenius to come to London, and published another work, _A
Reformation of Schools_. He had great influence and did not hesitate to
use it in his adoptive country. Everybody knew Hartlib, and he was
acquainted with all the strata of English society; for although his
father had been a merchant, first in Poland and later in Elbing, his
mother was the daughter of the Deputy of the English Company in Dantzic
and had relatives of rank in London, where Hartlib spent most of his
life. He gained the good-will of the Puritan Government, and even after
Cromwell's death was working, in conjunction with Boyle, for the
establishment of a national council of universal learning with Wilkins
as president.
When Comenius arrived in London he learned that the invitation had been
sent by order of Parliament. This body was very anxious to take up the
question of education, especially university education. Bacon's
criticisms of Oxford and Cambridge were still borne in mind; the
legislators considered that the college curriculum was in need of
reformation, that there ought to be more fraternity and correspondence
among the universities of Europe, and they even contemplated the
endowment by the State of scientific experiment. They spoke of erecting
a university at London, where Gresham College had been established in
1597 and Chelsea College in 1610. It was proposed to place Gresham
College, the Savoy, or Winchester College, at the disposition of the
pansophists. Comenius thought that nothing was more certain than that
the design of the great Verulam concerning the opening somewhere of a
universal college, devoted to the advancement of the sciences, could be
carried out. The impending struggle, however, between Charles I and the
Parliament prevented the attempt to realize the pansophic dream, and the
Austrian Slav, who knew something of the horrors of civil war, withdrew,
discouraged, to the Continent.
Nevertheless, Hartlib did not abandon the cause, but in 1644 broached
Milton on the subject of educational reform, and drew from him the brief
but influential tract on _Education_. In this its author alludes rather
slightingly to Comenius, who had something of Bacon's infelicity in
choice of titles and epithets and who must have seemed outlandish to the
author of _Lycidas_ and _Comus_. But Milton joined in the criticism of
the universities--the study of words rather than things--and advocated
an encyclopedic education based on the Greek and Latin writers of a
practical and scientific tendency (Aristotle, Theophrastus, Cato, Varro,
Vitruvius, Seneca, and others). He outlined a plan for the establishment
of an institution to be known by the classical (and Shakespearian) name
"Academy"--a plan destined to have a great effect on education in the
direction indicated by the friends of pansophia.
In this same year Robert Boyle, then an eager student of eighteen just
returned to England from residence abroad, came under the influence of
the genial Hartlib. In 1646 he writes his tutor inquiring about books
on methods of husbandry and referring to the new philosophical college,
which valued no knowledge but as it had a tendency to use. A few months
later he was in correspondence with Hartlib in reference to the
Invisible College, and had written a third friend that the corner-stones
of the invisible, or, as they termed themselves, the philosophical
college, did now and then honor him with their company. These
philosophers whom Boyle entertained, and whose scientific acumen,
breadth of mind, humility, and universal good-will he found so
congenial, were the nucleus of the Royal Society of London, of which, on
its definite organization in 1662, he was the foremost member. They had
begun to meet together in London about 1645, worthy persons inquisitive
into natural philosophy--Wilkins, interested in the navigation of the
air and of waters below the surface; Wallis, mathematician and
grammarian; the many-sided Petty, political economist, and inventor of a
double-bottomed boat, who had as a youth of twenty studied with Hobbes
in Paris in 1643, and in 1648 was to write his first treatise on
industrial education at the suggestion of Hartlib, and finally make a
survey of Ireland and acquire large estates; Foster, professor of
astronomy at Gresham College; Theodore Haak from the Pfalz; a number of
medical men, Dr. Merret, Dr. Ent, a friend of Harvey, Dr. Goddard, who
could always be relied upon to undertake an experiment, Dr. Glisson, the
physiologist, author in 1654 of a treatise on the liver (_De Hepate_),
and others. They met once a week at Goddard's in Wood Street, at the
Bull's Head Tavern in Cheapside, and at Gresham College.
Dr. Wilkins, the brother-in-law of Cromwell, who is regarded by some as
the founder of the Royal Society, removed to Oxford, as Warden of
Wadham, in 1649. Here he held meetings and conducted experiments in
conjunction with Wallis, Goddard, Petty, Boyle, and others, including
Ward (afterwards Bishop of Salisbury) interested in Bulliau's Astronomy;
and the celebrated physician and anatomist, Thomas Willis, author of a
work on the brain (_Cerebri Anatome_), and another on fevers (_De
Febribus_), in which he described epidemic typhoid as it occurred during
the Civil War in 1643.
In the mean time the weekly meetings in London continued, and were
attended when convenient by members of the Oxford group. At Gresham
College by 1658 it was the custom to remain for discussion Wednesdays
and Thursdays after Mr. Wren's lecture and Mr. Rooke's. During the
unsettled state of the country after Cromwell's death there was some
interruption of the meetings, but with the accession of Charles II in
1660 there came a greater sense of security. New names appear on the
records, Lord Brouncker, Sir Robert Moray, John Evelyn, Brereton, Ball,
Robert Hooke, and Abraham Cowley.
[Illustration: _From a print of 1675_
WADHAM COLLEGE, OXFORD]
Plans were discussed for a more permanent form of organization,
especially on November 28, 1660, when something was said of a design to
found a college for the promotion of physico-mathematical experimental
learning. A few months later was published Cowley's proposition for an
endowed college with twenty professors, four of whom should be
constantly traveling in the interests of science. The sixteen resident
professors "should be bound to study and teach all sorts of natural,
experimental philosophy, to consist of the mathematics, mechanics,
medicine, anatomy, chemistry, the history of animals, plants, minerals,
elements, etc.; agriculture, architecture, art military, navigation,
gardening; the mysteries of all trades and improvement of them; the
facture of all merchandise, all natural magic or divination; and briefly
all things contained in the Catalogue of Natural Histories annexed to my
Lord Bacon's _Organon_." The early official history of the Royal Society
(Sprat, 1667) says that this proposal hastened very much the adoption of
a plan of organization. Cowley wished to educate youth and incur great
expense (£4,000), but "most of the other particulars of his draught the
Royal Society is now putting in practice."
A charter of incorporation was granted in July, 1662; and, later,
Charles II proclaimed himself founder and patron of the Royal Society
for the advancement of natural science. Charles continued to take an
interest in this organization, devoted to the discovery of truth by the
corporate action of men; he proposed subjects for investigation, and
asked their coöperation in a more accurate measurement of a degree of
latitude. He showed himself tactful to take account of the democratic
spirit of scientific investigation, and recommended to the Royal Society
John Graunt, the author of a work on mortality statistics first
published in 1661. Graunt was a shop-keeper of London, and Charles said
that if they found any more such tradesmen, they should be sure to admit
them all without more ado.
It was a recognized principle of the Society freely to admit men of
different religions, countries, professions. Sprat said that they openly
professed, not to lay the foundation of an English, Scotch, Irish,
Popish or Protestant philosophy, but a philosophy of mankind. They
sought (hating war as most of them did) to establish a universal
culture, or, as they phrased it, a constant intelligence throughout all
civil nations. Even for the special purposes of the Society, hospitality
toward all nations was necessary; for the ideal scientist, the perfect
philosopher, should have the diligence and inquisitiveness of the
northern nations, and the cold and circumspect and wary disposition of
the Italians and Spaniards. Haak from the German Palatinate was one of
the earliest Fellows of the Society, and is even credited by Wallis with
being the first to suggest the meetings of 1645. Oldenburg from Bremen
acted as secretary (along with Wilkins) and carried on an extensive
foreign correspondence. Huygens of Holland was one of the original
Fellows in 1663, while the names of Auzout, Sorbière, the Duke of
Brunswick, Bulliau, Cassini, Malpighi, Leibnitz, Leeuwenhoek (as well as
Winthrop and Roger Williams) appear in the records of the Society within
the first decade. It seemed fitting that this cosmopolitan organization
should be located in the world's metropolis rather than in a mere
university town. Sprat thought London the natural seat of a universal
philosophy.
As already implied, the Royal Society was not exclusive in its attitude
toward the different vocations. A spirit of true fellowship prevailed in
Gresham College, as the Society was sometimes called. The medical
profession, the universities, the churches, the court, the army, the
navy, trade, agriculture, and other industries were there represented.
Social partition walls were broken down, and the Fellows, sobered by
years of political and religious strife, joined, mutually assisting one
another, in the advance of science for the sake of the common weal.
Their express purpose was the improvement of all professions from the
highest general to the lowest artisan. Particular attention was paid to
the trades, the mechanic arts, and the fostering of inventions. One of
their eight committees dealt with the histories of trades; another was
concerned with mechanical inventions, and the king ordained in 1662 that
no mechanical device should receive a patent before undergoing
their scrutiny. A great many inventions emanated from the Fellows
themselves--Hooke's hygroscope; Boyle's hydrometer, of use in the
detection of counterfeit coin; and, again, the tablet anemometer used by
Sir Christopher Wren (the Leonardo da Vinci of his age) to register the
velocity of the wind. A third committee devoted itself to agriculture,
and in the Society's museum were collected products and curiosities of
the shop, mine, sea, etc. One Fellow advised that attention should be
paid even to the least and plainest of phenomena, as otherwise they
might learn the romance of nature rather than its true history. So bent
were they on preserving a spirit of simplicity and straightforwardness
that in their sober discussions they sought to employ the language of
artisans, countrymen, and merchants rather than that of wits and
scholars.
Of course there was in the Society a predominance of gentlemen of means
and leisure, "free and unconfined." Their presence was thought to serve
a double purpose. It checked the tendency to sacrifice the search of
truth to immediate profit, and to lay such emphasis on application, as,
in the words of a subsequent president of the Society, would make truth,
and wisdom, and knowledge of no importance for their own sakes. In the
second place their presence was held to check dogmatism on the part of
the leaders, and subservience on the part of their followers. They
understood how difficult it is to transmit knowledge without putting
initiative in jeopardy and that quiet intellect is easily dismayed in
the presence of bold speech. The Society accepted the authority of no
one, and adopted as its motto _Nullius in Verba_.
In this attitude they were aided by their subject and method. Search for
scientific truth by laboratory procedure does not favor dogmatism. The
early meetings were taken up with experiments and discussions. The
Fellows recognized that the mental powers are raised to a higher degree
in company than in solitude. They welcomed diversity of view and the
common-sense judgment of the onlooker. As in the Civil War the private
citizen had held his own with the professional soldier, so here the
contribution of the amateur to the discussion was not to be despised.
They had been taught to shun all forms of narrowness and intolerance.
They wished to avoid the pedantry of the mere scholar, and the allied
states of mind to which all individuals are liable; they valued the
concurring testimony of the well-informed assembly. In the investigation
of truth by the experimental method they even arrived at the view that
"true experimenting has this one thing inseparable from it, never to be
a fixed and settled art, and never to be limited by constant rules." In
its incipience at least it is evident that the Royal Society was filled
with the spirit of tolerance and coöperation, and was singularly free
from the spirit of envy and faction.
Not least important of the joint labors of the Society were its
publications, which established contacts and stimulated research
throughout the scientific world. Besides the _Philosophical
Transactions_, which, since their first appearance in 1665, are the most
important source of information concerning the development of modern
science, the Royal Society printed many important works, among which the
following will indicate its early achievements:--
Hooke, Robert, _Micrographia: or some Physiological Descriptions of
Minute Bodies made by Magnifying Glasses_. 1665.
Graunt, John, _Natural and Political Observations ... made upon the
Bills of Mortality, with reference to the Government, Religion,
Trade, Growth, Air, Diseases, and the several changes of the City_.
3d edition, 1665.
Sprat, Thomas, _The History of the Royal Society of London, for the
Improving of Natural Knowledge_. 1667.
Malpighi, Marcello, _Dissertatio epistolica de Bombyce; Societati Regiæ
Londini dicata_. 1669. (On the silkworm.)
Evelyn, John, _Sylva, or a Discourse of Forest Trees_. 1670.
Horrocks, Jeremiah, _Opera [Astronomica] postuma_. 1673.
Malpighi, Marcello, _Anatome Plantarum_. 1675.
Willughby, Francis, _Ornithology_ (revised by John Ray). 1676.
Evelyn, John, _A Philosophical Discourse of Earth, relating to the
Culture and Improvement of it for Vegetation_. 1676.
Grew, Nehemiah, _The Anatomy of Plants_. 1682.
Willughby, F., _Historia Piscium_. 1686.
Ray, John, _Historia Plantarum_. 2 vols., 1686-88.
Flamsteed, John, _Tide-Table for 1687_.
Newton, Isaac, _Philosophiæ Naturalis Principia Mathematica_. Autore
Is. Newton. Imprimatur: S. Pepys, Reg. Soc. Præses. Julii 5, 1686.
4to. Londini, 1687.
After the Society had ordered that Newton's _Mathematical Principles of
Natural Philosophy_ should be printed, it was found that the funds had
been exhausted by the publication of Willughby's book on fishes. It was
accordingly agreed that Halley should undertake the business of looking
after it, and printing it at his own charge, which he had engaged to do.
Shortly after, the President of the Royal Society, Mr. Samuel Pepys, was
desired to license Mr. Newton's book.
It was not merely by defraying the expense of publication that Halley
contributed to the success of the _Principia_. He, Wren, Hooke, and
other Fellows of the Royal Society, concluded in 1684 that if Kepler's
third law were true, then the attraction exerted on the different
planets would vary inversely as the square of the distance. What, then,
would be the orbit of a planet under a central attraction varying as the
inverse square of the distance? Halley found that Newton had already
determined that the form of the orbit would be an ellipse. Newton had
been occupied with the problem of gravitation for about eighteen years,
but until Halley induced him to do so, had hesitated, on account of
certain unsettled points, to publish his results.
He writes: "I began (1666) to think of gravity extending to the orb of
the moon, ... and thereby compared the force requisite to keep the moon
in her orb with the force of gravity at the surface of the earth, and
found them answer pretty nearly." As early as March of that same year
Hooke had communicated to the Society an account of experiments in
reference to the force of gravity at different distances from the
surface of the earth, either upwards or downwards. At this and at every
point in Newton's discovery the records of co-workers are to be found.
By Flamsteed, the first Royal Astronomer, were supplied more accurate
data for the determination of planetary orbits. To Huygens Newton was
indebted for the laws of centrifugal force. Two doubts had made his
meticulous mind pause--one, of the accuracy of the data in reference to
the measurement of the meridian, another, of the attraction of a
spherical shell upon an external point. In the first matter the Royal
Society, as we have seen, had been long interested, and Picard, who had
worked on the measurement of the earth under the auspices of the
Académie des Sciences, brought his results, which came to the attention
of Newton, before the Royal Society in 1672. The second difficulty was
solved by Newton himself in 1685, when he proved that a series of
concentric spherical shells would act on an external point as if their
mass were concentrated at the center. For his calculations henceforth
the planets and stars, comets and all other bodies are points acted on
by lines of force, and "Every particle of matter in the universe
attracts every other particle with a force varying inversely as the
square of their mutual distances, and directly as the mass of the
attracting particle." He deduced from this law that the earth must be
flattened at the poles; he determined the orbit of the moon and of
comets; he explained the precession of the equinoxes, the semi-diurnal
tides, the ratio of the mass of the moon and the earth, of the sun and
the earth, etc. No wonder that Laplace considered that Newton's
_Principia_ was assured a preëminence above all the other productions of
the human intellect. It is no detraction from Newton's merit to say that
Halley, Hooke, Wren, Huygens, Bulliau, Picard, and many other
contemporaries (not to mention Kepler and _his_ predecessors), as well
as the organizations in which they were units, share the glory of the
result which they coöperated to achieve. On the contrary, he seems much
more conspicuous in the social firmament because, in spite of the
austerity and seeming independence of his genius, he formed part of a
system, and was under its law.
[Illustration: _Portrait by John Van der Bank_ _By permission of W. A.
Maxwell & Co._
SIR ISAAC NEWTON]
Shortly after the founding of the Royal Society, correspondence, for
which a committee was appointed, had been adopted as a means of gaining
the coöperation of men and societies elsewhere. Sir John Moray, as
President, wrote to Monsieur de Monmort, around whom, after the death of
Mersenne, the scientific coterie in Paris had gathered. This group of
men, which toward the close of the seventeenth century regarded itself,
not unnaturally, as the parent society, was in 1666 definitely organized
as the Académie Royale des Sciences. Finally, Leibnitz, who had been a
Fellow of the Royal Society as early as 1673, and had spent years in
the service of the Dukes of Brunswick, was instrumental in the
establishment in 1700 of the Prussian Akademie der Wissenschaften at
Berlin.
REFERENCES
Sir David Brewster, _Memoirs of Sir Isaac Newton_.
E. Conradi, Learned Societies and Academies in Early Times,
_Pedagogical Seminary_, vol. XII (1905), pp. 384-426.
Abraham Cowley, _A Proposition for the Advancement of Experimental
Philosophy_.
D. Masson, _Life of Milton_. Vol. III, chap. II.
Thomas Sprat, _The History of the Royal Society of London_.
_The Record of the Royal Society_ (third edition, 1912).
CHAPTER IX
SCIENCE AND THE STRUGGLE FOR LIBERTY--BENJAMIN FRANKLIN
Of the Fellows of the Royal Society, Benjamin Franklin (1706-1790) is
the most representative of that age of enlightenment which had its
origin in Newton's _Principia_. Franklin represents the eighteenth
century in his steadfast pursuit of intellectual, social, and political
emancipation. And in his long fight, calmly waged, against the forces of
want, superstition, and intolerance, such as still hamper the
development of aspiring youth in America, England, and elsewhere, he
found science no mean ally.
There is some reason for believing that the Franklins (_francus_--free)
were of a free line, free from that vassalage to an overlord, which in
the different countries of Europe did not cease to exist with the Middle
Ages. For hundreds of years they had lived obscurely near Northampton.
They had early joined the revolt against the papal authority. For
generations they were blacksmiths and husbandmen. Franklin's
great-grandfather had been imprisoned for writing satirical verses about
some provincial magnate. Of the grandfather's four sons the eldest
became a smith, but having some ingenuity and scholarly ability turned
conveyancer, and was recognized as able and public-spirited. The other
three were dyers. Franklin's father Josiah and his Uncle Benjamin were
nonconformists, and conceived the plan of emigrating to America in
order to enjoy their way of religion with freedom.
Benjamin, born at Boston, twenty-one years after his father's
emigration, was the youngest of ten sons, all of whom were eventually
apprenticed to trades. The father was a man of sound judgment who
encouraged sensible conversation in his home. Uncle Benjamin, who did
not emigrate till much later, showed interest in his precocious
namesake. Both he and the maternal grandfather expressed in verse
dislike of war and intolerance, the one with considerable literary
skill, the other with a good deal of decent plainness and manly freedom,
as his grandson said.
Benjamin was intended as a tithe to the Church, but the plan was
abandoned because of lack of means to send him to college. After one
year at the Latin Grammar School, and one year at an arithmetic and
writing school, for better or worse, his education of that sort ceased;
and at the age of ten he began to assist in his father's occupation, now
that of tallow-chandler and soap-boiler. He wished to go to sea, and
gave indications of leadership and enterprise. His father took him to
visit the shops of joiners, bricklayers, turners, braziers, cutlers, and
other artisans, thus stimulating in him a delight in handicraft.
Finally, because of a bookish turn he had been exhibiting, the boy was
bound apprentice to his brother James, who about 1720 began to publish
the _New England Courant_, the fourth newspaper to be established in
America.
Among the books early read by Benjamin Franklin were _The Pilgrim's
Progress_, certain historical collections, a book on navigation, works
of Protestant controversy, Plutarch's _Lives_, filled with the spirit
of Greek freedom, Dr. Mather's _Bonifacius_, and Defoe's _Essay on
Projects_. The last two seemed to give him a way of thinking, to adopt
Franklin's phraseology, that had an influence on some of the principal
events of his life. Defoe, an ardent nonconformist, educated in one of
the Academies (established on Milton's model) and especially trained in
English and current history, advocated among other projects a military
academy, an academy for improving the vernacular, and an academy for
women. He thought it barbarous that a civilized and Christian country
should deny the advantages of learning to women. They should be brought
to read books and especially history. Defoe could not think that God
Almighty had made women so glorious, with souls capable of the same
accomplishments with men, and all to be only stewards of our houses,
cooks, and slaves.
Benjamin still had a hankering for the sea, but he recognized in the
printing-office and access to books other means of escape from the
narrowness of the Boston of 1720. Between him and another bookish boy,
John Collins, arose an argument in reference to the education of women.
The argument took the form of correspondence. Josiah Franklin's
judicious criticism led Benjamin to undertake the well-known plan of
developing his literary style.
Passing over his reading of the _Spectator_, however, it is remarkable
how soon his mind sought out and assimilated its appropriate
nourishment, Locke's _Essay on the Human Understanding_, which began the
modern epoch in psychology; the _Port Royal Logic_, prepared by that
brilliant group of noble Catholics about Pascal; the works of Locke's
disciple Collins, whose _Discourse on Freethinking_ appeared in 1713;
the ethical writings (1708-1713) of Shaftesbury, who defended liberty
and justice, and detested all persecution. A few pages of translation of
Xenophon's _Memorabilia_ gave him a hint as to Socrates' manner of
discussion, and he made it his own, and avoided dogmatism.
Franklin rapidly became expert as a printer, and early contributed
articles to the paper. His brother, however, to whom he had been bound
apprentice for a period of nine years, humiliated and beat him. Benjamin
thought that the harsh and tyrannical treatment he received at this time
was the means of impressing him with that aversion to arbitrary power
that stuck to him through his whole life. He had a strong desire to
escape from his bondage, and, after five years of servitude, found the
opportunity. James Franklin, on account of some offensive utterances in
the _New England Courant_, was summoned before the Council and sent to
jail for one month, during which time Benjamin, in charge of the paper,
took the side of his brother and made bold to give the rulers some rubs.
Later, James was forbidden to publish the paper without submitting to
the supervision of the Secretary of the Province. To evade the
difficulty the _New England Courant_ was published in Benjamin's name,
James announcing his own retirement. In fear that this subterfuge might
be challenged, he gave Benjamin a discharge of his indentures, but at
the same time signed with him a new secret contract. Fresh quarrels
arose between the brothers, however, and Benjamin, knowing that the
editor dared not plead before court the second contract, took upon
himself to assert his freedom, a step which he later regretted as not
dictated by the highest principle.
Unable to find other employment in Boston, condemned by his father's
judgment in the matter of the contract, somewhat under public criticism
also for his satirical vein and heterodoxy, Franklin determined to try
his fortunes elsewhere. Thus, at the age of seventeen he made his escape
from Boston.
Unable to find work in New York, he arrived after some difficulties in
Philadelphia in October, 1723. He had brought no recommendations from
Boston; his supply of money was reduced to one Dutch dollar and a
shilling in copper. But he that hath a Trade hath an Estate (as Poor
Richard says). His capital was his industry, his skill as a printer, his
good-will, his shrewd powers of observation, his knowledge of books, and
ability to write. Franklin, recognized as a promising young man by the
Governor, Sir William Keith, as previously by Governor Burnet of New
York, had a growing sense of personal freedom and self-reliance.
But increased freedom for those who deserve it means increased
responsibility; for it implies the possibility of error. Franklin,
intent above all on the wise conduct of life, was deeply perturbed in
his nineteenth and twentieth years by a premature engagement, in which
his ever-passionate nature had involved him, by his failure to pay over
money collected for a friend, and by the unsettled state of his
religious and ethical beliefs. Encouraged by Keith to purchase the
equipment for an independent printing-office, Franklin, though unable to
gain his father's support for the project, went to London (for the
ostensible purpose of selecting the stock) at the close of the year
1724.
He remained in London a year and a half, working in two of the leading
printing establishments of the metropolis, where his skill and
reliability were soon prized. He found the English artisans of that time
great guzzlers of beer, and influenced some of his co-workers to adopt
his own more abstinent and hygienic habits of eating and drinking. About
this time a book, _Religion of Nature Delineated_, by William Wollaston
(great-grandfather of the scientist Wollaston) so roused Franklin's
opposition that he wrote a reply, which he printed in pamphlet form
before leaving London in 1726, and the composition of which he
afterwards regretted.
He returned to Philadelphia in the employ of a Quaker merchant, on whose
death he resumed work as printer under his former employer. He was given
control of the office, undertook to make his own type, contrived a
copper-plate press, the first in America, and printed paper money for
New Jersey. The substance of some lectures in defense of Christianity,
in courses endowed by the will of Robert Boyle, made Franklin a Deist.
At the same time his views on moral questions were clarified, and he
came to recognize that truth, sincerity, and integrity were of the
utmost importance to the felicity of life. What he had attained by his
own independent thought rendered him ultimately more careful rather than
more reckless. He now set value on his own character, and resolved to
preserve it.
In 1727, still only twenty-one, he drew together a number of young men
in a sort of club, called the "Junto," for mutual benefit in business
and for the discussion of morals, politics, and natural philosophy. They
professed tolerance, benevolence, love of truth. They discussed the
effect on business of the issue of paper money, various natural
phenomena, and kept a sharp look-out for any encroachment on the rights
of the people. It is not unnatural to find that in a year or two (1729),
after Franklin and a friend had established a printing business of their
own and acquired the _Pennsylvania Gazette_, the young politician
championed the cause of the Massachusetts Assembly against the claims
first put forward by Governor Burnet, and that he used spirited language
referring to America as a nation and clime foreign to England.
In 1730 Franklin bought out his partner, and in the same year published
dialogues in the Socratic manner in reference to virtue and pleasure,
which show a rapid development in his general views. About the same time
he married, restored the money that had long been owing, and formulated
his ethical code and religious creed. He began in 1732 the _Poor Richard
Almanacks_, said to offer in their homely wisdom the best course in
existence in practical morals.
As early as 1729 Franklin had published a pamphlet on _Paper Currency_.
It was a well-reasoned discussion on the relation of the issue of paper
currency to rate of interest, land values, manufactures, population, and
wages. The want of money discouraged laboring and handicraftsmen. One
must consider the nature and value of money in general. This essay
accomplished its purpose in the Assembly. It was the first of those
contributions which, arising from Franklin's consideration of the social
and industrial circumstances of the times, gained for him recognition as
the first American economist. It was in the same spirit that in 1751 he
discussed the question of population after the passage of the British
Act forbidding the erection or the operation of iron or steel mills in
the colonies. Science for Franklin was no extraneous interest; he was
all of a piece, and it was as a citizen of Philadelphia he wrote those
essays that commanded the attention of Adam Smith, Malthus, and Turgot.
In 1731 he was instrumental in founding the first of those public
libraries, which (along with a free press) have made American tradesmen
and farmers as intelligent, in Franklin's judgment, as most gentlemen
from other countries, and contributed to the spirit with which they
defended their liberties. The diffusion of knowledge became so general
in the colonies that in 1766 Franklin was able to tell the English
legislators that the seeds of liberty were universally found there and
that nothing could eradicate them. Franklin became clerk of the General
Assembly and postmaster, improved the paving and lighting of the city
streets, and established the first fire brigade and the first police
force in America. Then in 1743 in the same spirit of public beneficence
Franklin put forth his _Proposal for Promoting Useful Knowledge among
the British Plantations in America_. It outlines his plan for the
establishment of the American Philosophical Society. Correspondence had
already been established with the Royal Society of London. It is not
difficult to see in Franklin the same spirit that had animated Hartlib,
Boyle, Petty,[2] Wilkins, and their friends one hundred years before. In
fact, Franklin was the embodiment of that union of scientific ideas and
practical skill in the industries that with them was merely a pious
wish.
In this same year of 1743 an eclipse of the moon, which could not be
seen at Philadelphia on account of a northeast storm, was yet visible at
Boston, where the storm came, as Franklin learned from his brother,
about an hour after the time of observation. Franklin, who knew
something of fireplaces, explained the matter thus: "When I have a fire
in my chimney, there is a current of air constantly flowing from the
door to the chimney, but the beginning of the motion was at the
chimney." So in a mill-race, water stopped by a gate is like air in a
calm. When the gate is raised, the water moves forward, but the motion,
so to speak, runs backward. Thus the principle was established in
meteorology that northeast storms arise to the southwest.
No doubt Franklin was not oblivious of the practical value of this
discovery, for, as Sir Humphry Davy remarked, he in no instance
exhibited that false dignity, by which philosophy is kept aloof from
common applications. In fact, Franklin was rather apologetic in
reference to the magic squares and circles, with which he sometimes
amused his leisure, as a sort of ingenious trifling. At the very time
that the question of the propagation of storms arose in his mind he had
contrived the Pennsylvania fireplace, which was to achieve cheap,
adequate, and uniform heating for American homes. His aspiration was for
a free people, well sheltered, well fed, well clad, well instructed.
In 1747 Franklin made what is generally considered his chief
contribution to science. One of his correspondents, Collinson (a Fellow
of the Royal Society and a botanist interested in useful plants, through
whom the vine was introduced into Virginia), had sent to the Library
Company at Philadelphia one of the recently invented Leyden jars with
instructions for its use. Franklin, who had already seen similar
apparatus at Boston, and his friends, set to work experimenting. For
months he had leisure for nothing else. In this sort of activity he had
a spontaneous and irrepressible delight. By March, 1747, they felt that
they had made discoveries, and in July, and subsequently, Franklin
reported results to Collinson. He had observed that a pointed rod
brought near the jar was much more efficacious than a blunt rod in
drawing off the charge; also that if a pointed rod were attached to the
jar, the charge would be thrown off, and accumulation of charge
prevented. Franklin, moreover, found that the nature of the charges on
the inside and on the outside of the glass was different. He spoke of
one as plus and the other as minus. Again, "We say _B_ (and bodies
like-circumstanced) is electricized positively; _A_ negatively." Dufay
had recognized two sorts of electricity, obtained by rubbing a glass
rod and a stick of resin, and had spoken of them as vitreous and
resinous. For Franklin electricity was a single subtle fluid, and
electrical manifestations were owing to the degree of its presence, to
interruption or restoration of equilibrium.
His mind, however, was bent on the use, the applications, the
inventions, to follow. He contrived an "electric jack driven by two
Leyden jars and capable of carrying a large fowl with a motion fit for
roasting before a fire." He also succeeded in driving an "automatic"
wheel by electricity, but he regretted not being able to turn his
discoveries to greater account.
He thought later--in 1748--that there were many points of similarity
between lightning and the spark from a Leyden jar, and suggested an
experiment to test the identity of their natures. The suggestion was
acted upon at Marly in France. An iron rod about forty feet long and
sharp at the end was placed upright in the hope of drawing electricity
from the storm-clouds. A man was instructed to watch for storm-clouds,
and to touch a brass wire, attached to a glass bottle, to the rod. The
conditions seemed favorable May 10, 1752; sparks between the wire and
rod and a "sulphurous" odor were perceived (the manifestations of
wrath!). Franklin's well-known kite experiment followed. In 1753 he
received from the Royal Society a medal for the identification and
control of the forces of lightning; subsequently he was elected Fellow,
became a member of the Académie des Sciences, and of other learned
bodies. By 1782 there were as many as four hundred lightning rods in
use in Philadelphia alone, though some conservative people regarded
their employment as impious. Franklin's good-will, clearness of
conception, and common sense triumphed everywhere.
One has only to recall that in 1753 he (along with Hunter) was in charge
of the postal service of the colonies, that in 1754 as delegate to the
Albany Convention he drew up the first plan for colonial union, and that
in the following year he furnished Braddock with transportation for the
expedition against Fort Duquesne, to realize the distractions amid which
he pursued science. In 1748 he had sold his printing establishment with
the purpose of devoting himself to physical experiment, but the
conditions of the time saved him from specialization.
In 1749 he drew up proposals relating to the education of youth in
Pennsylvania, which led, two years later, to the establishment of the
first American Academy. His plan was so advanced, so democratic,
springing as it did from his own experience, that no secondary school
has yet taken full advantage of its wisdom. The school, chartered in
1753, grew ultimately into the University of Pennsylvania. Moreover, it
became the prototype of thousands of schools, which departed from the
Latin Grammar Schools and the Colleges by the introduction of the
sciences and practical studies into the curriculum.
Franklin deserves mention not only in connection with economics,
meteorology, practical ethics, electricity, and pedagogy; his biographer
enumerates nineteen sciences to which he made original contributions or
which he advanced by intelligent criticism. In medicine he invented
bifocal lenses and founded the first American public hospital; in
navigation he studied the Gulf Stream and waterspouts, and suggested the
use of oil in storms and the construction of ships with water-tight
compartments; in agriculture he experimented with plaster of Paris as a
fertilizer and introduced in America the use of rhubarb; in chemistry he
aided Priestley's experiments by information in reference to marsh gas.
He foresaw the employment of air craft in war. Thinking the English slow
to take up the interest in balloons, he wrote that we should not suffer
pride to prevent our progress in science. Pride that dines on vanity
sups on contempt, as Poor Richard says. When it was mentioned in his
presence that birds fly in inclined planes, he launched a half sheet of
paper to indicate that his previous observations had prepared his mind
to respond readily to the discovery. His quickness and versatility made
him sought after by the best intellects of Europe.
I pass over his analysis of mesmerism, his conception of light as
dependent (like lightning) on a subtle fluid, his experiments with
colored cloths, his view of the nature of epidemic colds, interest in
inoculation for smallpox, in ventilation, vegetarianism, a stove to
consume its own smoke, the steamboat, and his own inventions (clock,
harmonica, etc.), for which he refused to take out patents.
However, from the many examples of his scientific acumen I select one
more. As early as 1747 he had been interested in geology and had seen
specimens of the fossil remains of marine shells from the strata of the
highest parts of the Alleghany Mountains. Later he stated that either
the sea had once stood at a higher level, or that these strata had been
raised by the force of earthquakes. Such convulsions of nature are not
wholly injurious, since, by bringing a great number of strata of
different kinds today, they have rendered the earth more fit for use,
more capable of being to mankind a convenient and comfortable
habitation. He thought it unlikely that a great _bouleversement_ should
happen if the earth were solid to the center. Rather the surface of the
globe was a shell resting on a fluid of very great specific gravity, and
was thus capable of being broken and disordered by violent movement. As
late as 1788 Franklin wrote his queries and conjectures relating to
magnetism and the theory of the earth. Did the earth become magnetic by
the development of iron ore? Is not magnetism rather interplanetary and
interstellar? May not the near passing of a comet of greater magnetic
force than the earth have been a means of changing its poles and thereby
wrecking and deranging its surface, and raising and depressing the sea
level?
We are not here directly concerned with his political career, in his
checking of governors and proprietaries, in his activities as the
greatest of American diplomats, as the signer of the Declaration of
Independence, of the Treaty of Versailles, and of the American
Constitution, nor as the president of the Supreme Executive Council of
Pennsylvania in his eightieth, eighty-first, and eighty-second years.
When he was eighty-four, as president of the Society for Promoting the
Abolition of Slavery, he signed a petition to Congress against that
atrocious debasement of human nature, and six weeks later, within a few
weeks of his death, defended the petition with his accustomed vigor,
humor, wisdom, and ardent love of liberty. Turgot wittily summed up
Franklin's career by saying that he had snatched the lightning from the
heavens and the scepter from the hands of tyrants (_eripuit cœlo fulmen
sceptrumque tyrannis_); for both his political and scientific activities
sprang from the same impelling emotion--hatred of the exercise of
arbitrary power and desire for human welfare. It is no wonder that the
French National Assembly, promulgators of the Rights of Man, paused in
their labors to pay homage to the simple citizen, who, representing
America in Paris from his seventy-first till his eightieth year, had by
his wisdom and urbanity illustrated the best fruits of an instructed
democracy.
REFERENCES
American Philosophical Society, _Record of the Celebration of the Two
Hundredth Anniversary of the Birth of Benjamin Franklin_.
S. G. Fisher, _The True Benjamin Franklin_.
Paul L. Ford, _Many-sided Franklin_.
Benjamin Franklin, _Complete Works_, edited by A. H. Smyth, ten
volumes, vol. X containing biography.
FOOTNOTES:
[2] See _The Advice of W. P. to Mr. Samuel Hartlib for the Advancement
of some Particular Parts of Learning_, in which is advocated a
_Gymnasium Mechanicum_ or a _College of Tradesmen_ with fellowships for
experts. Petty wanted trade encyclopedias prepared, and hoped for
inventions in abundance.
CHAPTER X
THE INTERACTION OF THE SCIENCES--WERNER, HUTTON, BLACK, HALL, WILLIAM
SMITH
The view expressed by Franklin regarding the existence of a fiery mass
underlying the crust of the earth was not in his time universally
accepted. In fact, it was a question very vigorously disputed what part
the internal or volcanic fire played in the formation and modification
of rock masses. Divergent views were represented by men who had come to
the study of geology with varying aims and diverse scientific schooling,
and the advance of the science of the earth's crust was owing in no
small measure to the interaction of the different sciences which the
exponents of the various points of view brought to bear.
Abraham Gottlob Werner (1750-1817) was the most conspicuous and
influential champion on the side of the argument opposed to the
acceptance of volcanic action as one of the chief causes of geologic
formations. He was born in Saxony and came of a family which had engaged
for three hundred years in mining and metal working. They were active in
Saxony when George Agricola prepared his famous works on metallurgy and
mineralogy inspired by the traditional wisdom of the local iron
industry. Werner's father was an overseer of iron-works, and furnished
his son with mineral specimens as playthings before the child could
pronounce their names. In 1769 Werner was invited to attend the newly
founded Bergakademie (School of Mines) at Freiberg. Three years later he
went to the University of Leipzig, but, true to his first enthusiasm,
wrote in 1774 concerning the outward characteristics of minerals (_Von
den äusserlichen Kennzeichen der Fossilien_). The next year he was
recalled to Freiberg as teacher of mineralogy and curator of
collections. He was intent on classification, and might be compared in
that respect with the naturalist Buffon, or the botanist Linnæus. He
knew that chemistry afforded a surer, but slower, procedure; his was a
practical, intuitive, field method. He observed the color, the hardness,
weight, fracture of minerals, and experienced the joy the youthful mind
feels in rapid identification. He translated Cronstedt's book on
mineralogy descriptive of the practical blow-pipe tests. After the
identification of minerals, Werner was interested in their discovery,
the location of deposits, their geographical distribution, and the
relative positions of different kinds of rocks, especially the constant
juxtaposition or superposition of one stratum in relation to another.
Werner was an eloquent, systematic teacher with great charm of manner.
He kept in mind the practical purposes of mining, and soon people
flocked to Freiberg to hear him from all the quarters of Europe. He had
before long disciples in every land. He saw all phenomena from the
standpoint of the geologist. He knew the medicinal, as well as the
economic, value of minerals. He knew the relation of the soil to the
rocks, and the effects of both on racial characteristics. Building-stone
determines style of architecture. Mountains and river-courses have
bearing on military tactics. He turned his linguistic knowledge to
account and furnished geology with a definite nomenclature. Alex. v.
Humboldt, Robert Jameson, D'Aubuisson, Weiss (the teacher of Froebel),
were among his students. Crystallography and mineralogy became the
fashion. Goethe was among the enthusiasts, and philosophers like
Schelling, under the spell of the new science, almost deified the
physical universe.
Werner considered all rocks as having originated by crystallization,
either chemical or mechanical, from an aqueous solution--a universal
primitive ocean. He was a Neptunist, as opposed to the Vulcanists or
Plutonists, who believed in the existence of a central fiery mass.
Werner thought that the earth showed universal strata like the layers of
an onion, the mountains being formed by erosion, subsidence, cavings-in.
In his judgment granite was a primitive rock formed previous to animal
and vegetable life (hence without organic remains) by chemical
precipitation. Silicious slate was formed later by mechanical
crystallization. At this period organized fossils first appear.
Sedimentary rocks, like old red sandstone, and, according to Werner,
basalt, are in a third class. Drift, sand, rubble, boulders, come next;
and finally volcanic products, like lava, ashes, pumice. He was quite
positive that all basalt was of aqueous origin and of quite recent
formation. This part of his teaching was soon challenged. He was truer
to his own essential purposes in writing a valuable treatise on
metalliferous veins (_Die Neue Theorie der Erzgänge_), but even there
his general views are apparent, for he holds that veins are clefts
filled in from above by crystallization from aqueous solution.
Before Werner had begun his teaching career at Freiberg, Desmarest, the
French geologist, had made a special study of the basalts of Auvergne.
As a mathematician he was able to make a trigonometrical survey of that
district, and constructed a map showing the craters of volcanoes of
different ages, the streams of lava following the river courses, and the
relation of basalt to lava, scoria, ashes, and other recognized products
of volcanic action. In 1788 he was made inspector-general of French
manufactures, later superintendent of the porcelain works at Sèvres. He
lived to the age of ninety, and whenever Neptunists would try to draw
him into argument, the old man would simply say, "Go and see."
James Hutton (1726-1797), the illustrious Scotch geologist, had
something of the same aversion to speculation that did not rest on
evidence; though he was eminently a philosopher in the strictest sense
of the word, as his three quarto volumes on the _Principles of
Knowledge_ bear witness. Hutton was well trained at Edinburgh in the
High School and University. In a lecture on logic an illustrative
reference to _aqua regia_ turned his mind to the study of chemistry. He
engaged in experiments, and ultimately made a fortune by a process for
the manufacture of sal ammoniac from coal-soot. In the mean time he
studied medicine at Edinburgh, Paris, and Leyden, and continued the
pursuit of chemistry. Then, having inherited land in Berwickshire, he
studied husbandry in Norfolk and took interest in the surface of the
land and water-courses; later he pursued these studies in Flanders.
During years of highly successful farming, during which Hutton
introduced new methods in Berwickshire, he was interested in
meteorology, and in geology as related to soils. In 1768, financially
independent, Dr. Hutton retired to reside in Edinburgh.
He was very genial and sociable and was in close association with Adam
Smith, the economist, and with Black, known in the history of chemistry
in connection with carbonic acid, latent heat, and experiments in
magnesia, quicklime, and other alkaline substances (1777). Playfair,
professor of mathematics, and later of natural philosophy, was Hutton's
disciple and intimate friend. In the distinguished company of the Royal
Society of Edinburgh, established in 1782, the founder of dynamic
geology was stimulated by these and other distinguished men like William
Robertson, Lord Kames, and Watt. The first volume of the _Transactions_
contains his _Theory of Rains_, and the first statement of his famous
_Theory of the Earth_. He was very broad-minded and enthusiastic and
would rejoice in Watt's improvements of the steam engine or Cook's
discoveries in the South Pacific. Without emphasizing his indebtedness
to Horace-Bénédict de Saussure, physicist, geologist, meteorologist,
botanist, who gave to Europeans an appreciation of the sublime in
nature, nor dwelling further on the range of Hutton's studies in
language, general physics, etc., it is already made evident that his
mind was such as to afford comprehensiveness of view.
He expressed the wish to induce men who had sufficient knowledge of the
particular branches of science, to employ their acquired talents in
promoting general science, or knowledge of the great system, where ends
and means are wisely adjusted in the constitution of the material
universe. Philosophy, he says, is surely the ultimate end of human
knowledge, or the object at which all sciences properly must aim.
Sciences no doubt should promote the arts of life; but, he proceeds,
what are all the arts of life, or all the enjoyments of mere animal
nature, compared with the art of human happiness, gained by education
and brought to perfection by philosophy? Man must learn to know himself;
he must see his station among created things; he must become a moral
agent. But it is only by studying things in general that he may arrive
at this perfection of his nature. "To philosophize, therefore, without
proper science, is in vain; although it is not vain to pursue science,
without proceeding to philosophy."
In the early part of 1785 Dr. Hutton presented his _Theory of the Earth_
in ninety-six pages of perfectly lucid English. The globe is studied as
a machine adapted to a certain end, namely, to provide a habitable world
for plants, for animals, and, above all, for intellectual beings capable
of the contemplation and the appreciation of order and harmony. Hutton's
theory might be made plain by drawing an analogy between geological and
meteorological activities. The rain descends on the earth; streams and
rivers bear it to the sea; the aqueous vapors, drawn from the sea,
supply the clouds, and the circuit is complete. Similarly, the soil is
formed from the overhanging mountains; it is washed as sediment into
the sea; it is elevated, after consolidation, into the overhanging
mountains. The earth is more than a mechanism, it is an organism that
repairs and restores itself in perpetuity. Thus Hutton explained the
composition, dissolution, and restoration of land upon the globe on a
general principle, even as Newton had brought a mass of details under
the single law of gravitation.
Again, as Newton had widened man's conception of space, so Hutton (and
Buffon) enlarged his conception of time. For the geologist did not
undertake to explain the _origin_ of things; he found no vestige of a
beginning,--no prospect of an end; and at the same time he conjured up
no hypothetical causes, no catastrophes, or sudden convulsions of
nature; neither did he (like Werner) believe that phenomena now present,
were once absent; but he undertook to explain all geological change by
processes in action now as heretofore. Countless ages were requisite to
form the soil of our smiling valleys, but "Time, which measures
everything in our _idea_, and is often deficient to our schemes, is to
nature endless and as nothing." The calcareous remains of marine animals
in the solid body of the earth bear witness of a period to which no
other species of chronology is able to remount.
Hutton's imagination, on the basis of what can be observed to-day,
pictured the chemical and mechanical disintegration of the rocks; and
saw ice-streams bearing huge granite boulders from the declivities of
primitive and more gigantic Alps. He believed (as Desmarest) that
rivulets and rivers have constructed, and are constructing, their own
valley systems, and that the denudation ever in progress would be
eventually fatal to the sustenance of plant and animal and man, if the
earth were not a renewable organism, in which repair is correlative with
waste.
All strata are sedimentary, consolidated at the bottom of the sea by the
pressure of the water and by subterranean heat. How are strata raised
from the ocean bed? By the same subterranean force that helped
consolidate them. The power of heat for the expansion of bodies, is,
says Hutton (possibly having in mind the steam engine), so far as we
know, unlimited. We see liquid stone pouring from the crater of a lofty
volcano and casting huge rocks into mid-air, and yet find it difficult
to believe that Vesuvius and Etna themselves have been formed by
volcanic action. The interior of the planet may be a fluid mass, melted,
but unchanged by the action of heat. The volcanoes are spiracles or
safety-valves, and are widely distributed on the surface of the earth.
Hutton believed that basalt, and the whinstones generally, are of
igneous origin. Moreover, he put granite in the same category, and
believed it had been injected, as also metalliferous veins, in liquid
state into the stratified rocks. If his supposition were correct, then
granite would be found sending out veins from its large masses to pierce
the stratified rocks and to crop out where stratum meets stratum. His
conjecture was corroborated at Glen Tilt (and in the island of Arran).
Hutton was so elated at the verification of his view that the Scotch
guides thought he had struck gold, or silver at the very least. In the
bed of the river Tilt he could see at six points within half a mile
powerful veins of red granite piercing the black micaceous schist and
giving every indication of having been intruded from beneath, with great
violence, into the earlier formation.
Hutton felt confirmed in his view that in nature there is wisdom,
system, and consistency. Even the volcano and earthquake, instead of
being accidents, or arbitrary manifestations of divine wrath, are part
of the economy of nature, and the best clue we have to the stupendous
force necessary to heave up the strata, inject veins of metals and
igneous rocks, and insure a succession of habitable worlds.
In 1795 Dr. Hutton published a more elaborate statement of his theory in
two volumes. In 1802 Playfair printed _Illustrations of the Huttonian
Theory_, a simplification, having, naturally, little originality. Before
his death in 1797 Hutton devoted his time to reading new volumes by
Saussure on the Alps, and to preparing a book on _The Elements of
Agriculture_.
Sir James Hall of Dunglass was a reluctant convert to Hutton's system of
geology. Three arguments against the Huttonian hypothesis gave him cause
for doubt. Would not matter solidifying after fusion form a glass, a
vitreous, rather than a crystalline product? Why do basalts, whinstones,
and other supposedly volcanic rocks differ so much in structure from
lava? How can marble and other limestones have been _fused_, seeing that
they are readily calcined by heat? Hutton thought that the compression
under which the subterranean heat had been applied was a factor in the
solution of these problems. He was encouraged in this view by Black,
who, as already implied, had made a special study of limestone and had
demonstrated that lime acquires its causticity through the expulsion of
carbonic acid.
Hall conjectured in addition that the rate at which the fused mass
cooled might have some bearing on the structure of igneous rocks. An
accident in the Leith glass works strengthened the probability of his
conjecture and encouraged him to experiment. A pot of green bottle-glass
had been allowed to cool slowly with the result that it had a stony,
rather than a vitreous structure. Hall experimenting with glass could
secure either structure at will by cooling rapidly or slowly, and that
with the same specimen.
He later enclosed some fragments of whinstone in a black-lead crucible
and subjected it to intense heat in the reverberating furnace of an iron
foundry. (He was in consultation with Mr. Wedgwood on the scale of heat,
and with Dr. Hope and Dr. Kennedy, chemists.) After boiling, and then
cooling rapidly, the contents of the crucible proved a black glass. Hall
repeated the experiment, and cooled more slowly. The result was an
intermediate substance, neither glass nor whinstone--a sort of slag.
Again he heated the crucible in the furnace, and removed quickly to an
open fire, which was maintained some hours and then permitted to die
out. The result in this case was a perfect whinstone. Similar results
were obtained with regular basalts and different specimens of igneous
rock.
Hall next experimented with lava from Vesuvius, Etna, Iceland, and
elsewhere, and found that it behaved like whinstone. Dr. Kennedy by
careful chemical analysis confirmed Hall's judgment of the similarity
of these two igneous products.
Still later Hall introduced chalk and powdered limestone into porcelain
tubes, gun barrels, and tubes bored in solid iron, which he sealed and
brought to very high temperatures. He obtained, by fusion, a crystalline
carbonate resembling marble. Under the high pressure in the tube the
carbonic acid was retained. By these and other experiments this doubting
disciple confirmed Hutton's theory, and became one of the great founders
of experimental geology.
It remained for William Smith (1769-1839), surveyor and engineer, to
develop that species of chronology that Hutton had ascribed to organic
remains in the solid strata, to arrange these strata in the order of
time, and thus to become the founder of historic geology. For this task
his early education might at first glance seem inadequate. His only
schooling was received in an elementary institution in Oxfordshire. He
managed, however, to acquire some knowledge of geometry, and at eighteen
entered, as assistant, a surveyor's office. He never attained any
literary facility, and was always more successful in conveying his
observations by maps, drawings, and conversation than by books.
However, he early began his collection of minerals and observed the
relation of the soil and the vegetation to the underlying rocks. Engaged
at the age of twenty-four in taking levelings for a canal, he noticed
that the strata were not exactly horizontal, but dipped to the east
"like slices of bread and butter," a phenomenon he considered of
scientific significance. In connection with his calling he had an
opportunity of traveling to the north of England and so extended the
range of his observation, always exceptionally alert. For six years he
was engaged, as engineer, in the construction of the Somerset Coal
Canal, where he enlarged and turned to practical account his knowledge
of strata.
Collectors of fossils (as Lamarck afterwards called organic remains)
were surprised to find Smith able to tell in what formation their
different specimens had been found, and still more when he enunciated
the view that "whatever strata were to be found in any part of England
the same remains would be found in it and no other." Moreover, the same
order of superposition was constant among the strata, as Werner, of whom
Smith knew nothing, had indeed taught. Smith was able to dictate a
_Tabular View of British Strata_ from coal to chalk with the
characteristic fossils, establishing an order that was found to obtain
on the Continent of Europe as well as in Britain.
He constructed geological maps of Somerset and fourteen other English
counties, to which the attention of the Board of Agriculture was called.
They showed the surface outcrops of strata, and were intended to be of
assistance in mining, roadmaking, canal construction, draining, and
water supply. It was at the time of William Smith's scientific
discoveries that the public interest in canal transportation was at its
height in England, and his study of the strata was a direct outcome of
his professional activity. He called himself a mineral surveyor, and he
traveled many thousand miles yearly in connection with his calling and
his interest in the study of geology. In 1815 he completed an extensive
geological map of England, on which all subsequent geological maps have
been modeled. It took into account the collieries, mines, canals,
marshes, fens, and the varieties of soil in relation to the substrata.
Later (1816-1819) Smith published four volumes, _Strata Identified by
Organized Fossils_, which put on record some of his extensive
observations. His mind was practical and little given to speculation. It
does not lie in our province here to trace his influence on Cuvier and
other scientists, but to add his name as a surveyor and engineer to the
representatives of mineralogy, chemistry, physics, mathematics,
philosophy, and various industries and vocations, which contributed to
the early development of modern geology.
REFERENCES
Sir A. Geikie, _Founders of Geology_.
James Hutton, _Theory of the Earth_.
Sir Charles Lyell, _Principles of Geology_.
John Playfair, _Illustrations of the Huttonian Theory_.
K. A. v. Zittel, _History of Geology and Palæontology_.
CHAPTER XI
SCIENCE AND RELIGION--KANT, LAMBERT, LAPLACE, SIR WILLIAM HERSCHEL
Hutton had advanced the study of geology by concentrating attention on
the observable phenomena of the earth's crust, and turning away from
speculations about the origin of the world and the relation of this
sphere to other units of the cosmos. In the same century, however, other
scientists and philosophers were attracted by these very problems which
seemed not to promise immediate or demonstrative solution, and through
their studies they arrived at conclusions which profoundly affected the
science, the ethics, and the religion of the civilized world.
Whether religion be defined as a complex feeling of elation and
humility--a sacred fear--akin to the æsthetic sense of the sublime; or,
as an intellectual recognition of some high powers which govern us
below--of some author of all things, of some force social or cosmic
which tends to righteousness; or, as the outcrop of the moral life
touched with light and radiant with enthusiasm; or, as partaking of the
nature of all these: it cannot be denied that the eighteenth century
contributed to its clarification and formulation, especially through the
efforts of the German philosopher, Immanuel Kant (1724-1804). Yet it is
not difficult to show that the philosophy of Kant and of those
associated with him was greatly influenced by the science of the time,
and that, in fact, in his early life he was a scientist rather than a
philosopher in the stricter sense. His _General Natural History and
Theory of the Heavens_, written at the age of thirty-one, enables us to
follow his transition from science to philosophy, and, more especially,
to trace the influence of his theory of the origin of the heavenly
bodies on his religious conceptions.
For part of this theory Kant was indebted to Thomas Wright of Durham
(1711-1786). Wright was the son of a carpenter, became apprenticed to a
watchmaker, went to sea, later became an engraver, a maker of
mathematical instruments, rose to affluence, wrote a book on navigation,
and was offered a professorship of navigation in the Imperial Academy of
St. Petersburg. It was in 1750 that he published, in the form of nine
letters, the work that stimulated the mind of Kant, _An Original Theory
or New Hypothesis of the Universe_. The author thought that the
revelation of the structure of the heavens naturally tended to propagate
the principles of virtue and vindicate the laws of Providence. He
regarded the universe as an infinity of worlds acted upon by an eternal
Agent, and full of beings, tending through their various states to a
final perfection. Who, conscious of this system, can avoid being filled
with a kind of enthusiastic ambition to contribute his atom toward the
due admiration of its great and Divine Author?
Wright discussed the nature of mathematical certainty and the various
degrees of moral probability proper for conjecture (thus pointing to a
distinction that ultimately became basal in the philosophy of Kant).
When he claimed that the sun is a vast body of blazing matter, and that
the most distant star is also a sun surrounded by a system of planets,
he knew that he was reasoning by analogy and not enunciating what is
immediately demonstrable. Yet this multitude of worlds opens out to us
an immense field of probation and an endless scene of hope to ground our
expectation of an ever future happiness upon, suitable to the native
dignity of the awful Mind which made and comprehended it.
The most striking part of Wright's _Original Theory_ relates to the
construction of the Milky Way, which he thought analogous in form to the
rings of Saturn. From the center the arrangement of the systems and the
harmony of the movements could be discerned, but our solar system
occupies a section of the belt, and what we see of the creation gives
but a confused picture, unless by an effort of imagination we attain the
right point of view. The various cloudy stars or light appearances are
nothing but a dense accumulation of stars. What less than infinity can
circumscribe them, less than eternity comprehend them, or less than
Omnipotence produce or support them? He passes on to a discussion of
time and space with regard to the known objects of immensity and
duration, and in the ninth letter says that, granting the creation to be
circular or orbicular, we can suppose in the center of the whole an
intelligent principle, the to-all-extending eye of Providence, or, if
the creation is real, and not merely ideal, a sphere of some sort.
Around this the suns keep their orbits harmoniously, all apparent
irregularities arising from our eccentric view. Moreover, space is
sufficient for many such systems.
Kant resembled his predecessor in his recognition of the bearing on
moral and religious conceptions of the study of the heavens and also in
his treatment of many astronomical details, sometimes merely adopting,
more frequently developing or modifying, the teachings of Wright. He
held that the stars constitute a system just as much as do the planets
of our solar system, and that other solar systems and other Milky Ways
may have been produced in the boundless fields of space. Indeed, he is
inclined to identify with the latter systems the small luminous
elliptical areas in the heavens reported by Maupertuis in 1742. Kant
also accepted Wright's conjecture of a central sun or globe and even
made selection of one of the stars to serve in that office, and taught
that the stars consist like our sun of a fiery mass. One cannot
contemplate the world-structure without recognizing the excellent
orderliness of its arrangement, and perceiving the sure indications of
the hand of God in the completeness of its relations. Reason, he says in
the _Allgemeine Naturgeschichte_, refuses to believe it the work of
chance. It must have been planned by supreme wisdom and carried into
effect by Omnipotence.
Kant was especially stimulated by the analogy between the Milky Way and
the rings of Saturn. He did not agree with Wright that they, or the
cloudy areas, would prove to be stars or small satellites, but rather
that both consisted of vapor particles. Giving full scope to his
imagination, he asks if the earth as well as Saturn may not have been
surrounded by a ring. Might not this ring explain the supercelestial
waters that gave such cause for ingenuity to the medieval writers? Not
only so, but, had such a vaporous ring broken and been precipitated to
the earth, it would have caused a prolonged Deluge, and the subsequent
rainbow in the heavens might very well have been interpreted as an
allusion to the vanished ring, and as a promise. This, however, is not
Kant's characteristic manner in supporting moral and religious truth.
To account for the origin of the solar system, the German philosopher
assumes that at the beginning of all things the material of which the
sun, planets, satellites, and comets consist, was uncompounded, in its
primary elements, and filled the whole space in which the bodies formed
out of it now revolve. This state of nature seemed to be the very
simplest that could follow upon nothing. In a space filled in this way a
state of rest could not last for more than a moment. The elements of a
denser kind would, according to the law of gravitation, attract matter
of less specific gravity. Repulsion, as well as attraction, plays a part
among the particles of matter disseminated in space. Through it the
direct fall of particles may be diverted into a circular movement about
the center toward which they are gravitating.
Of course, in our system the center of attraction is the nucleus of the
sun. The mass of this body increases rapidly, as also its power of
attraction. Of the particles gravitating to it the heavier become heaped
up in the center. In falling from different heights toward this common
focus the particles cannot have such perfect equality of resistance that
no lateral movements should be set up. A general circulatory motion is
in fact established ultimately in one direction about the central mass,
which receiving new particles from the encircling current rotates in
harmony with it.
Mutual interference in the particles outside the mass of the sun
prevents all accumulation except in one plane and that takes the form of
a thin disk continuous with the sun's equator. In this circulating
vaporous disk about the sun differences of density give rise to zones
not unlike the rings of Saturn. These zones ultimately contract to form
planets, and as the planets are thrown off from the central solar mass
till an equilibrium is established between the centripetal and
centrifugal forces, so the satellites in turn are formed from the
planets. The comets are to be regarded as parts of the system, akin to
the planets, but more remote from the control of the centripetal force
of the sun. It is thus that Kant conceived the nebular hypothesis,
accounting (through the formation of the heavenly bodies from a cloudy
vapor similar to that still observable through the telescope) for the
revolution of the planets in one direction about the sun; the rotation
of sun and planets; the revolution and rotation of satellites; the
comparative densities of the heavenly bodies; the materials in the tails
of comets; the rings of Saturn, and other celestial phenomena. Newton,
finding no matter between the planets to maintain the community of their
movements, asserted that the immediate hand of God had instituted the
arrangement without the intervention of the forces of Nature. His
disciple Kant now undertook to explain an additional number of
phenomena on mechanical principles. Granted the existence of matter, he
felt capable of tracing the cosmic evolution, but at the same time he
maintained and strengthened his religious position, and did not assume
(like Democritus and Epicurus) eternal motion without a Creator or the
coming together of atoms by accident or haphazard.
It might be objected, he says, that Nature is sufficient unto itself;
but universal laws of the action of matter serve the plan of the Supreme
Wisdom. There is convincing proof of the existence of God in the very
fact that Nature, even in chaos, cannot proceed otherwise than regularly
and according to law. Even in the essential properties of the elements
that constituted the chaos, there could be traced the mark of that
perfection which they have derived from their origin, their essential
character being a consequence of the eternal idea of the Divine
Intelligence. Matter, which appears to be merely passive and wanting in
form and arrangement, has in its simplest state a tendency to fashion
itself by a natural development into a more perfect constitution. Matter
must be considered as created by God in accordance with law and as ever
obedient to law, not as an independent or hostile force needing
occasional correction. To suppose the material world not under law would
be to believe in a blind fate rather than in Providence. It is Nature's
harmony and order revealed to our understanding that give us a clue to
its creation by an understanding of the highest order.
In a work written eight years later Kant sought to furnish people of
ordinary intelligence with a proof of the existence of God. It might
seem irrelevant in such a production to give an exposition of physical
phenomena, but, intent on his method of mounting to a knowledge of God
by means of natural science, he here repeats in summarized form his
theory of the origin of the heavenly bodies. Moreover, the influence of
his astronomical studies persisted in his maturest philosophy, as can be
seen in the well-known passage at the conclusion of his ethical work,
the _Critique of the Practical Reason_ (1788): "There are two things
that fill my spirit with ever new and increasing awe and reverence--the
more frequently and the more intently I contemplate them--the
star-strewn sky above me and the moral law within." His religious and
ethical conceptions were closely associated with--indeed, dependent
upon--an orderly and infinite physical universe.
In the mathematician, astronomer, physicist, and philosopher, J. H.
Lambert (1728-1777), Kant found a genius akin to his own, and through
him hoped for a reformation of philosophy on the basis of the study of
science. Lambert like his contemporary was a disciple of Newton, and in
1761 he published a book in the form of letters expressing views in
reference to the Milky Way, fixed stars, central sun, very similar to
those published by Kant in 1755. Lambert had heard of Wright's work, so
similar to his own, a year after the latter was written.
Comets, now robbed of many of the terrors with which ancient
superstition endowed them, might, he says, seem to threaten catastrophe,
by colliding with the planets or by carrying off a satellite. But the
same hand which has cast the celestial spheres in space, has traced
their course in the heavens, and does not allow them to wander at
random to disturb and destroy each other. Lambert imagines that all
these bodies have exactly the volume, weight, position, direction, and
speed necessary for the avoidance of collisions. If we confess a Supreme
Ruler who brought order from chaos, and gave form to the universe; it
follows that this universe is a perfect work, the impress, picture,
reflex of its Creator's perfection. Nothing is left to blind chance.
Means are fitted to ends. There is order throughout, and in this order
the dust beneath our feet, the stars above our heads, atoms and worlds,
are alike comprehended.
Laplace in his statement of the nebular hypothesis made no mention of
Kant. He sets forth, in the _Exposition of the Solar System_, the
astronomical data that the theory is designed to explain: the movements
of the planets in the same direction and almost in the same plane; the
movements of the satellites in the same direction as those of the
planets; the rotation of these different bodies and of the sun in the
same direction as their projection, and in planes little different; the
small eccentricity of the orbits of planets and satellites; the great
eccentricity of the orbits of comets. How on the ground of these data
are we to arrive at the cause of the earliest movements of the planetary
system?
A fluid of immense extent must be assumed, embracing all these bodies.
It must have circulated about the sun like an atmosphere and, in virtue
of the excessive heat which was engendered, it may be assumed that this
atmosphere originally extended beyond the orbits of all the planets, and
was contracted by stages to its present form. In its primitive state
the sun resembled the nebulæ, which are to be observed through the
telescope, with fiery centers and cloudy periphery. One can imagine a
more and more diffuse state of the nebulous matter.
Planets were formed, in the plane of the equator and at the successive
limits of the nebulous atmosphere, by the condensation of the different
zones which it abandoned as it cooled and contracted. The force of
gravity and the centrifugal force sufficed to maintain in its orbit each
successive planet. From the cooling and contracting masses that were to
constitute the planets smaller zones and rings were formed. In the case
of Saturn there was such regularity in the rings that the annular form
was maintained; as a rule from the zones abandoned by the planet-mass
satellites resulted. Differences of temperature and density of the parts
of the original mass account for the eccentricity of orbits, and
deviations from the plane of the equator.
In his _Celestial Mechanics_ (1825) Laplace states that, according to
Herschel's observations, Saturn's rotation is slightly quicker than that
of its rings. This seemed a confirmation of the hypothesis of the
_Exposition du Système du Monde_.
When Laplace presented the first edition of this earlier work to
Napoleon, the First Consul said: "Newton has spoken of God in his book.
I have already gone through yours, and I have not found that name in it
a single time." To this Laplace is said to have replied: "First Citizen
Consul, I have not had need of that hypothesis." The astronomer did not,
however, profess atheism; like Kant he felt competent to explain on
mechanical principles the development of the solar system from the point
at which he undertook it. In his later years he desired that the
misleading anecdote should be suppressed. So far was he from
self-sufficiency and dogmatism that his last utterance proclaimed the
limitations of even the greatest intellects: "What we know is little
enough, what we don't know is immense" (_Ce que nous connaissons est peu
de chose, ce que nous ignorons est immense_).
Sir William Herschel's observations, extended over many years, confirmed
both the nebular hypothesis and the theory of the systematic arrangement
of the stars. He made use of telescopes 20 and 40 feet in focal length,
and of 18.7 and 48 inches aperture, and was thereby enabled, as Humboldt
said, to sink a plummet amid the fixed stars, or, in his own phrase, to
gauge the heavens. _The Construction of the Heavens_ was always the
ultimate object of his observations. In a contribution on this subject
submitted to the Royal Society in 1787 he announced the discovery of 466
new nebulæ and clusters of stars. The sidereal heavens are not to be
regarded as the concave surface of a sphere, from the center of which
the observer might be supposed to look, but rather as resembling a rich
extent of ground or chains of mountains in which the geologist discovers
many strata consisting of various materials. The Milky Way is one
stratum and in it our sun is placed, though perhaps not in the very
center of its thickness.
By 1811 he had greatly increased his observations of the nebulæ and
could arrange them in series differing in extent, condensation,
brightness, general form, possession of nuclei, situation, and in
resemblance to comets and to stars. They ranged from a faint trace of
extensive diffuse nebulosity to a nebulous star with a mere vestige of
cloudiness. Herschel was able to make the series so complete that the
difference between the members was no more than could be found in a
series of pictures of the human figure taken from the birth of a child
till he comes to be a man in his prime. The difference between the
diffuse nebulous matter and the star is so striking that the idea of
conversion from one to the other would hardly occur to any one without
evidence of the intermediate steps. It is highly probable that each
successive state is the result of the action of gravity.
In his last statement, 1818, he admitted that to his telescopes the
Milky Way had proved fathomless, but on "either side of this assemblage
of stars, presumably in ceaseless motion round their common center of
gravity, Herschel discovered a canopy of discrete nebulous masses, such
as those from the condensation of which he supposed the whole stellar
universe to be formed."
In the theory of the evolution of the heavenly bodies, as set forth by
Kant, Laplace, and Herschel, it was assumed that the elements that
composed the earth are also to be found elsewhere throughout the solar
system and the universe. The validity of this assumption was finally
established by spectrum analysis. But this vindication was in part
anticipated, at the beginning of the nineteenth century, by the analysis
of meteorites. In these were found large quantities of iron,
considerable percentages of nickel, as well as cobalt, copper, silicon,
phosphorus, carbon, magnesium, zinc, and manganese.
REFERENCES
G. F. Becker, Kant as a Natural Philosopher, _American Journal of
Science_, vol. V (1898), pp. 97-112.
W. W. Bryant, _A History of Astronomy_.
Agnes M. Clerke, _History of Astronomy during the Nineteenth Century_.
Agnes M. Clerke, _The Herschels and Modern Astronomy_.
Sir William Herschel, Papers on the Construction of the Heavens
(_Philosophical Transactions_, 1784, 1811, etc.).
A. R. Hinks, _Astronomy_ (Home University Library).
E. W. Maunders, _The Science of the Stars_ (The People's Books).
CHAPTER XII
THE REIGN OF LAW--DALTON, JOULE
In the middle of the eighteenth century, when Lambert and Kant were
recognizing system and design in the heavens, little progress had been
made toward discovering the constitution of matter or revealing the laws
of the hidden motions of things. Boyle had, indeed, made a beginning,
not only by his study of the elasticity of the air, but by his
distinction of the elements and compounds and his definition of
chemistry as the science of the composition of substances. How little
had been accomplished, however, is evident from the fact that in 1750
the so-called elements--earth, air, fire, water--which Bacon had marked
for examination in 1620, were still unanalyzed, and that no advance had
been made beyond his conception of the nature of heat, the majority,
indeed, of the learned world holding that heat is a substance (variously
identified with sulphur, carbon, or hydrogen) rather than a mode of
motion.
How scientific thought succeeded in bringing order out of confusion and
chaos in the subsequent one hundred years, and especially at the
beginning of the nineteenth century, can well be illustrated by these
very matters, the study of combustion, of heat as a form of energy, of
the constituents of the atmosphere, and of the chemistry of water and of
the earth.
Reference has already been made to Black's discovery of carbonic acid,
and of the phenomena which he ascribed to latent heat. The first
discovery (1754) was the result of the preparation of quicklime in the
practice of medicine; the second (1761) involving experiments on the
temperatures of melting ice, boiling water, and steam, stimulated Watt
in his improvement of the steam engine. In 1766 Joseph Priestley began
his study of airs, or gases. In the following year observation of work
in a brewery roused his curiosity in reference to carbonic acid. In 1772
he experimented with nitric oxide. In the previous century Mayow had
obtained nitric oxide by treating iron with nitric acid. He had then
introduced this gas into ordinary air confined over water, and found
that the mixture suffered a reduction of volume. Priestley applied this
process to the analysis of common air, which he discovered to be complex
and not simple. In 1774, by heating red oxide of mercury by means of a
burning-glass, he obtained a gas which supported combustion better than
common air. He inhaled it, and experienced a sense of exhilaration. "Who
can tell," he writes, "but in time this pure air may become a
fashionable article in luxury? Hitherto only two mice and myself have
had the privilege of breathing it."
The Swedish investigator Scheele had, however, discovered this same
constituent of the air before 1773. He thought that the atmosphere must
consist of at least two gases, and he proved that carbonic acid results
from combustion and respiration. In 1772 the great French scientist
Lavoisier found that sulphur, when burned, gains weight instead of
losing weight, and five years later he concluded that air consists of
two gases, one capable of absorption by burning bodies, the other
incapable of supporting combustion. He called the first "oxygen." In his
_Elements of Chemistry_ Lavoisier gave a clear exposition of his system
of chemistry and of the discoveries of other European chemists. After
his studies the atmosphere was no longer regarded as mysterious and
chaotic. It was known to consist largely of oxygen and nitrogen, and to
contain in addition aqueous vapor, carbonic acid, and ammonia which
might be brought to earth by rain.
Cavendish obtained nitrogen from air by using nitric oxide to remove the
oxygen, and found that air consists of about seventy-nine per cent
nitrogen and about twenty-one per cent oxygen. He also by use of the
electric spark caused the oxygen and nitrogen of the air to unite to
form nitric acid. When the nitrogen was exhausted and the redundant
oxygen removed, "only a small bubble of air remained unabsorbed."
Similarly Cavendish had found that water results from the combination of
oxygen and hydrogen. Watt had likewise held that water is not an
element, but a compound of two elementary substances. Thus the great
masses,--earth, air, fire, water,--assumed as simple by many
philosophers from the earliest times, were resolving into their
constituent parts. At the same time other problems were demanding
solution. What are the laws of chemical combination? What is the
relation of heat to other forms of energy? To the answering of these
questions (as of those from which these grew) the great manufacturing
centers contributed, and no city more potently than Manchester through
Dalton and his pupil and follower Joule.
John Dalton (1766-1844) was born in Cumberland, went to Kendal to teach
school at the age of fifteen, and remained in the Lake District of
England till 1793. In this region, where the annual rainfall exceeds
forty inches, and in some localities is almost tropical, the young
student's attention was early drawn to meteorology. His apparatus
consisted of rude home-made rain-gauges, thermometers, and barometers.
His interest in the heat, moisture, and constituents of the atmosphere
continued throughout life, and Dalton made in all some 200,000
meteorological observations. We gain a clue to his motive in these
studies from a letter written in his twenty-second year, in which he
speaks of the advantages that might accrue to the husbandman, the
mariner, and to mankind in general if we were able to predict the state
of the weather with tolerable precision.
In 1793 Dalton took up his permanent residence in Manchester, and in
that year appeared his first book, _Meteorological Observations and
Essays_. Here he deals, among other things, with rainfall, the formation
of clouds, evaporation, and the distribution and character of
atmospheric moisture. It seemed to him that aqueous vapor always exists
as a distinct fluid maintaining its identity among the other fluids of
the atmosphere. He thought of atmospheric moisture as consisting of
minute drops of water, or globules among the globules of oxygen and
nitrogen. He was a disciple of Newton's (to whom, indeed, Dalton had
some personal likeness), who looked upon matter as consisting of "solid,
massy, hard, impenetrable, movable particles, of such sizes and figures,
and with such other properties, and in such proportion, as most
conduced to the end for which God formed them." Dalton was so much under
the influence of the idea that the physical universe is made up of these
indivisible particles, or atoms, that his biographer describes him as
thinking _corpuscularly_. It is probable that his imagination was of the
visualizing type and that he could picture to himself the arrangement of
atoms in elementary and compound substances.
Now Dalton's master had taught that the atoms of matter in a gas
(elastic fluid) repel one another by a force increasing in proportion as
their distance diminishes. How did this teaching apply to the
atmosphere, which Priestley and others had proved to consist of three or
more gases? Why does this mixture appear simple and homogeneous? Why
does not the air form strata with the oxygen below and the nitrogen
above? Cavendish had shown, and Dalton himself later proved, that common
air, wherever examined, contains oxygen and nitrogen in fairly constant
proportions.
French chemists had sought to apply the principle of _chemical affinity_
in explaining the apparent homogeneity of the atmosphere. They supposed
that oxygen and nitrogen entered into chemical union, the one element
dissolving the other. The resultant compound in turn dissolved water;
hence the phenomena of evaporation. Dalton tried in vain to reconcile
this supposition with his belief in the atomic nature of matter. He drew
diagrams combining an atom of oxygen with an atom of nitrogen and an
atom of aqueous vapor. The whole atmosphere could not consist of such
groups of three because the watery particles were but a small portion of
the total atmosphere. He made a diagram in which one atom of oxygen was
combined with one atom of nitrogen, but in this case the oxygen was
insufficient to satisfy all the nitrogen of the atmosphere. If the air
was made up partly of pure nitrogen, partly of a compound of nitrogen
and oxygen, and partly of a compound of nitrogen, oxygen, and aqueous
vapor, then the triple compound, as heaviest, would collect toward the
surface of the earth, and the double compound and the simple substance
would form two strata above. If to the compounds heat were added in the
hope of producing an unstratified mixture, the atmosphere would acquire
the specific gravity of nitrogen gas. "In short," says Dalton, "I was
obliged to abandon the hypothesis of the chemical constitution of the
atmosphere altogether as irreconcilable to the phenomena."
He had to return to the conception of the individual particles of
oxygen, nitrogen, and water, each a center of repulsion. Still he could
not explain why the oxygen did not gravitate to the lowest place, the
nitrogen form a stratum above, and the aqueous vapor swim upon the top.
In 1801, however, Dalton hit upon the idea that gases act as _vacua_ for
one another, that it is only like particles which repel each other,
atoms of oxygen repelling atoms of oxygen and atoms of nitrogen
repelling atoms of nitrogen when these gases are intermingled in the
atmosphere just as they would if existing in an unmixed state.
"According to this, we were to suppose that atoms of one kind did _not_
repel the atoms of another kind, but only those of their own kind." A
mixed atmosphere is as free from stratifications, as though it were
really homogeneous.
In his analyses of air Dalton made use of the old nitric oxide method.
In 1802 this led to an interesting discovery. If in a tube .3 of an inch
wide he mixed 100 parts of common air with 36 parts of nitric oxide, the
oxygen of the air combined with the nitric oxide, and a residue of 79
parts of atmospheric nitrogen remained. And if he mixed 100 parts of
common air with 72 of nitric oxide, but in a wide vessel over water (in
which conditions the combination is more quickly effected), the oxygen
of the air again combined with the nitric oxide and a residue of 79
parts of nitrogen again resulted. But in the last experiment, if less
than 72 parts of nitric oxide be employed, there will be a residue of
oxygen as well as nitrogen; and if more than 72, there will be a residue
of nitric oxide in addition to the nitrogen. In the words of Dalton,
"oxygen may combine with a certain portion of nitrous gas [as he called
nitric oxide], or with twice that portion, but with no intermediate
portion."
Naturally these experimental facts were to be explained in terms of the
ultimate particles of which the various gases are composed. In the
following year Dalton gave graphic representation to his idea of the
atomic constitution of chemical elements and compounds.
( ) Hydrogen
(|) Nitrogen
(·) Oxygen
(*) Carbon
(|) (·) Nitric oxide
(·) (|) (·) Nitrous oxide
(·) (*) (·) Carbonic acid
Much against Dalton's will his method of indicating chemical elements
and their combinations had to yield to a method introduced by the great
Swedish chemist Berzelius. In 1837 Dalton wrote: "Berzelius's symbols
are horrifying: a young student in chemistry might as soon learn Hebrew
as make himself acquainted with them. They appear like a chaos of atoms
... and to equally perplex the adepts of science, to discourage the
learner, as well as to cloud the beauty and simplicity of the Atomic
Theory."
Meantime Dalton's mind had been turning to the consideration of the
relative sizes and weights of the various elements entering into
combination with one another. He argued that if there be not exactly the
same _number_ of atoms of oxygen in a given volume of air as of nitrogen
in the same volume, then the sizes of the particles of oxygen must be
different from those of nitrogen. His interest in the absorption of
gases by water, in the reciprocal diffusion of gases, as well as in the
phenomena of chemical combination, stimulated Dalton to determine the
_relative_ size and weight of the atoms of the various elements. Dalton
said nothing of the _absolute_ weight of the atom. But on the assumption
that when only one compound of two elements is known to exist, the
molecule of the compound consists of one atom of each of these elements,
he proceeded to investigate the relative weights of equal numbers of the
two sorts of atoms. In 1803 he pursued this investigation with
remarkable success, and taking hydrogen (the lightest gas known to him)
as unity, he arrived at a statement of the relative atomic weights of
oxygen, nitrogen, carbon, etc. Dalton thus introduced into the study of
chemical combination a very definite idea of quantitative relationship.
By him the atomic theory of the constitution of matter was made
definite and applicable to all the phenomena known to chemistry.
[Illustration: _Painting by Ford Madox Brown_ _By permission of the Town
Hall Committee of the Manchester Corporation_
JOHN DALTON COLLECTING MARSH GAS]
During the following months he returned to the study of those cases in
which the same elements combine to form more than one compound. We have
seen that oxygen unites with nitric oxide to form two compounds, and
that into the one compound twice as much nitric oxide (by weight) enters
as into the other. A like relation was found in the weight of oxygen
combining with carbon in the two compounds carbon monoxide and carbonic
acid. In the summer of 1804 he investigated the composition of two
compounds of hydrogen and carbon, marsh gas (methane) and olefiant gas
(ethylene), and found that the first contained just twice as much
hydrogen in relation to the carbon as the second compound contained. In
a series of compounds of the same two elements one atom of one unites
with one, two, three, or more atoms of the other; that is, a simple
ratio exists between the weights in which the second element enters into
combination with the first. This law of multiple proportions afforded
confirmation of Dalton's atomic theory, or chemical theory of definite
proportions.
"Without such a theory," says Sir Henry Roscoe, "modern chemistry would
be a chaos; with it, order reigns supreme, and every apparently
contradictory discovery only marks out more distinctly the value and
importance of Dalton's work." In 1826 Sir Humphry Davy recognized
Dalton's services to science in the following terms: "Finding that in
certain compounds of gaseous bodies the same elements always combined
in the same proportions, and that when there was more than one
combination the quantity of the elements always had a constant
relation,--such as 1 to 2, or 1 to 3, or 1 to 4,--he explained this fact
on the Newtonian doctrine of indivisible atoms; and contended that, the
relative weight of one atom to that of any other atom being known, its
proportions or weight in all its combinations might be ascertained, thus
making the statics of chemistry depend upon simple questions in
subtraction or multiplication and enabling the student to deduce an
immense number of facts from a few well-authenticated experimental
results. Mr. Dalton's permanent reputation will rest upon his having
discovered a simple principle universally applicable to the facts of
chemistry, in fixing the proportions in which bodies combine, and thus
laying the foundation for future labors respecting the sublime and
transcendental parts of the science of corpuscular motion. His merits in
this respect resemble those of Kepler in astronomy."
In 1808 Dalton's atomic theory received striking confirmation through
the investigations of the French scientist Gay-Lussac, who showed that
gases, under similar circumstances of temperature and pressure, always
combine in simple proportions by _volume_ when they act on one another,
and that when the result of the union is a gas, its volume also is in a
simple ratio to the volumes of its components. One of Dalton's friends
summed up the result of Gay-Lussac's research in this simple fashion:
"His paper is on the combination of gases. He finds that all unite in
equal bulks, or two bulks of one to one of another, or three bulks of
one to one of another." When Dalton had investigated the relative
weights with which elements combine, he had found no simple arithmetical
relationship between atomic weight and atomic weight. When two or more
compounds of the same elements are formed, Dalton found, however, as we
have seen, that the proportion of the element added to form the second
or third compound is a multiple by weight of the first quantity.
Gay-Lussac now showed that gases, "in whatever proportions they may
combine, always give rise to compounds whose elements by volume are
multiples of each other."
In 1811 Avogadro, in an essay on the relative masses of atoms, succeeded
in further confirming Dalton's theory and in explaining the atomic basis
of Gay-Lussac's discovery of simple volume relations in the formation of
chemical compounds. According to the Italian scientist the _number_ of
molecules in all gases is always the same for equal volumes, or always
proportional to the volumes, it being taken for granted that the
temperature and pressure are the same for each gas. Dalton had supposed
that water is formed by the union of hydrogen and oxygen, atom for atom.
Gay-Lussac found that two volumes of hydrogen combined with one volume
of oxygen to produce two volumes of water vapor. According to Avogadro
the water vapor contains twice as many atoms of hydrogen as of oxygen.
One volume of hydrogen has the same number of molecules as one volume of
oxygen. When the two volumes combine with one, the combination does
not take place, as Dalton had supposed, atom for atom, but each
half-molecule of oxygen combines with one molecule of hydrogen. The
symbol for water is, therefore, not HO but H{2}O.
Enough has been said to establish Dalton's claim to be styled a great
lawgiver of chemical science. His influence in further advancing
definitely formulated knowledge of physical phenomena can here be
indicated only in part. In 1800 he wrote a paper _On the Heat and Cold
produced by the Mechanical Condensation and Rarefaction of Air_. This
contains, according to Dalton's biographer, the first quantitative
statement of the heat evolved by compression and the heat evolved by
dilatation. His contribution to the theory of heat has been stated thus:
The volume of a gas under constant pressure expands when raised to the
boiling temperature by the same fraction of itself, whatever be the
nature of the gas. In 1798 Count Rumford had reported to the Royal
Society his _Enquiry concerning the Source of Heat excited by Friction_,
the data for which had been gathered at Munich. Interested as he was in
the practical problem of providing heat for the homes of the city poor,
Rumford had been struck by the amount of heat developed in the
boring-out of cannon at the arsenal. He concluded that anything which
could be created indefinitely by a process of friction could not be a
substance, such as sulphur or hydrogen, but must be a mode of motion. In
the same year the youthful Davy was following independently this line of
investigation by rubbing two pieces of ice together, by clock-work, in a
vacuum. The friction caused the ice to melt, although the experiment was
undertaken in a temperature of 29° Fahrenheit.
For James Prescott Joule (1818-1889), who came of a family of brewers
and was early engaged himself in the brewing industry, was reserved,
however, the distinction of discovering the exact relation between heat
and mechanical energy. After having studied chemistry under Dalton at
Manchester, he became engrossed in physical experimentation. In 1843 he
prepared a paper _On the Calorific Effects of Magneto-Electricity
and on the Mechanical Value of Heat_. In this he dealt with the
relations between heat and the ordinary forms of mechanical power,
and demonstrated that the mechanical energy spent "in turning a
magneto-electrical machine is _converted into the heat_ evolved by the
passage of the currents of induction through its coils; and, on the
other hand, that the motive power of the electro-magnetic engine is
obtained at the expense of the heat due to the chemical reactions of the
battery by which it is worked." In 1844 he proceeded to apply the
principles maintained in his earlier study to changes of temperature as
related to changes in the density of gases. He was conscious of the
practical, as well as the theoretical, import of his investigation.
Indeed, it was through the determination by this illustrious pupil of
Dalton's of the amount of heat produced by the compression of gases that
one of the greatest improvements of the steam engine was later effected.
Joule felt that his investigation at the same time confirmed the
dynamical theory of heat which originated with Bacon, and had at a
subsequent period been so well supported by the experiments of Rumford,
Davy, and others.
Already, in this paper of June, 1844, Joule had expressed the hope of
ascertaining the mechanical equivalent of heat with the accuracy that
its importance for physical science demanded. He returned to this
question again and again. According to his final result the quantity of
heat required to raise one pound of water in temperature by one degree
Fahrenheit is equivalent to the mechanical energy required to raise
772.55 pounds through a distance of one foot. Heat was thus demonstrated
to be a form of energy, the relation being constant between it and
mechanical energy. Mechanical energy may be converted into heat; if heat
disappears, some other form of energy, equivalent in amount to the heat
lost, must replace it. The doctrine that a certain quantity of heat is
always equivalent to a certain amount of mechanical energy is only a
special case of the Law of the Conservation of Energy, first clearly
enunciated by Joule and Helmholtz in 1847, and generally regarded as the
most important scientific discovery of the nineteenth century.
Roscoe, referring to the two life-sized marble statues which face each
other in the Manchester Town Hall, says with pardonable pride: "Thus
honor is done to Manchester's two greatest sons--to Dalton, the founder
of modern Chemistry and of the Atomic Theory, and the discoverer of the
laws of chemical combining proportions; to Joule, the founder of modern
Physics and the discoverer of the Law of the Conservation of Energy."
REFERENCES
Alembic Club Reprints, _Foundations of the Atomic Theory_.
Joseph Priestley, _Experiments and Observations on Different Kinds of
Air_.
Sir William Ramsay, _The Gases of the Atmosphere and the History of
their Discovery_.
Sir Henry E. Roscoe, _John Dalton_.
Sir E. Thorpe, _Essays in Historical Chemistry_.
CHAPTER XIII
THE SCIENTIST--SIR HUMPHRY DAVY
Humphry Davy (1778-1829) was born in Cornwall, a part of England known
for its very mild climate and the combined beauty and majesty of its
scenery. On either side of the peninsula the Atlantic in varying mood
lies extended in summer sunshine, or from its shroud of mist thunders on
the black cliffs and their time-sculptured sandstones. From the
coast inland, stretch, between flowered lanes and hedges, rolling
pasture-lands of rich green made all the more vivid by the deep reddish
tint of the ploughed fields. In Penzance, then a town of about three
thousand inhabitants, and in its picturesque vicinity, the early years
of Davy's life were passed. Across the bay rose the great vision of the
guarded mount (St. Michael's) of which Milton's verse speaks. Farther to
the east lay Lizard Head, the southernmost promontory of England, and a
few miles to the north St. Ives with its sweep of sandy beach; while not
far to the west of Penzance Land's End stood sentry "'Twixt two
unbounded seas." The youthful Davy was keenly alive to the charms of his
early environment, and his genius was susceptible to the belief in
supernatural agencies native to the imaginative Celtic people among whom
he was reared. As a precocious child of five he improvised rhymes, and
as a youth set forth in excellent verse the glories of Mount's Bay:--
"There did I first rejoice that I was born
Amidst the majesty of azure seas."
Davy received what is usually called a liberal education, putting in
nine years in the Penzance and one year in the Truro Grammar School. His
best exercises were translations from the classics into English verse.
He was rather idle, fond of fishing (an enthusiasm he retained
throughout life) and shooting, and less appreciated and beloved by his
masters than by his school-fellows, who recognized his wonderful
abilities, sought his aid in their Latin compositions (as well as in the
writing of letters and valentines), and listened eagerly to his
imaginative tales of wonder and horror. Years later he wrote to his
mother: "After all, the way in which we are taught Latin and Greek does
not much influence the important structure of our minds. I consider it
fortunate that I was left much to myself when a child, and put upon no
particular plan of study, and that I enjoyed much idleness at Mr.
Coryton's school. I perhaps owe to these circumstances the little
talents that I have and their peculiar application."
When Davy was about sixteen years old, his father died, leaving the
widow and her five children, of whom Humphry was the eldest, with very
scanty provision. The mind of the youth seemed to undergo an immediate
change. He expressed his resolution (which he nobly carried out) to play
his part as son and brother. Within a few weeks he became apprenticed to
an apothecary and surgeon, and, having thus found his vocation, drew up
his own particular plan of self-education, to which he rigidly adhered.
His brother, Dr. John Davy, bears witness that the following is
transcribed from a notebook of Humphry's, bearing the date of the same
year as his apprenticeship (1795):--
1. Theology or Religion } Taught by Nature.
Ethics or Moral Virtues } by Revelation.
2. Geography.
3. My Profession--
1. Botany. 2. Pharmacy. 3. Nosology. 4. Anatomy.
5. Surgery. 6. Chemistry.
4. Logic.
5. Language, etc.
A series of essays which Davy wrote in pursuing his scheme of
self-culture proves how rapidly his mind drew away from the
superstitions which characterized the masses of the people among whom he
lived. He had as a boy been haunted by the fear of monsters and witches
in which the credulous of all classes then believed. His notebook shows
that he was now subjecting to examination the religious and political
opinions of his time. He composed essays on the immortality and
immateriality of the soul, on governments, on the credulity of mortals,
on the dependence of the thinking powers on the organization of the
body, on the ultimate end of being, on happiness, and on moral
obligation. He studied the writings of Locke, Hartley, Berkeley, Hume,
Helvetius, Condorcet, and Reid, and knew something of German philosophy.
It was not till he was nineteen that Davy entered on the experimental
study of chemistry.
Guided by the _Elements_ of Lavoisier, encouraged by the friendship of
Gregory Watt (a son of James Watt) and by another gentleman of
university education, stimulated by contact with the Cornish mining
industry, Davy pursued this new study with zeal, and within a few months
had written two essays full of daring generalizations on the physical
sciences. These were published early in 1799. Partly on the basis of the
ingenious experiment mentioned in the preceding chapter, he came to the
conclusion that "Heat, or that power which prevents the actual contact
of the corpuscles of bodies, and which is the cause of our peculiar
sensations of heat and cold, may be defined as a peculiar motion,
probably a vibration, of the corpuscles of bodies, tending to separate
them." Other passages might be quoted from these essays to show how the
gifted youth of nineteen anticipated the science of subsequent decades,
but in the main these early efforts were characterized by the faults of
overwrought speculation and incomplete verification. He soon regretted
the premature publication of his studies. "When I consider," he wrote,
"the variety of theories that may be formed on the slender foundation of
one or two facts, I am convinced that it is the business of the true
philosopher to avoid them altogether. It is more laborious to accumulate
facts than to reason concerning them; but one good experiment is of more
value than the ingenuity of a brain like Newton's."
In the mean time Davy had been chosen superintendent of the Pneumatic
Institution at Bristol by Dr. Beddoes, its founder. It was supported by
the contributions of Thomas Wedgwood and other distinguished persons,
and aimed at discovering by means of experiment the physiological effect
of inhaling different gases, or "factitious airs," as they were called.
The founding of such an establishment has been termed a scientific
aberration, but the use now made in medical practice of oxygen, nitrous
oxide, chloroform, and other inhalations bears witness to the sanity of
the sort of research there set on foot. Even before going to Bristol,
Davy had inhaled small quantities of nitrous oxide mixed with air, in
spite of the fact that this gas had been held by a medical man to be the
"principle of contagion." He now carried on a series of tests, and
finally undertook an extended experiment with the assistance of a
doctor. In an air-tight or box-chamber he inhaled great quantities of
the supposedly dangerous gas. After he had been in the box an hour and a
quarter, he respired twenty quarts of pure nitrous oxide. He described
the experience in the following words:--
"A thrilling, extending from the chest to the extremities, was almost
immediately produced. I felt a sense of tangible extension highly
pleasurable in every limb; my visible impressions were dazzling, and
apparently magnified; I heard every sound in the room, and was perfectly
aware of my situation. By degrees, as the pleasurable sensations
increased, I lost all connection with external things; trains of vivid
visible images rapidly passed through my mind, and were connected with
words in such a manner, as to produce perceptions perfectly novel. I
existed in a world of newly connected and newly modified ideas: I
theorized, I imagined that I made discoveries. When I was awakened from
this semi-delirious trance by Dr. Kinglake, who took the bag from my
mouth, indignation and pride were the first feelings produced by the
sight of the persons about me. My emotions were enthusiastic and
sublime, and for a minute I walked round the room perfectly regardless
of what was said to me. As I recovered my former state of mind, I felt
an inclination to communicate the discoveries I had made during the
experiment. I endeavored to recall the ideas: they were feeble and
indistinct; one collection of terms, however, presented itself; and with
the most intense belief and prophetic manner, I exclaimed to Dr.
Kinglake, '_Nothing exists but thoughts! The universe is composed of
impressions, ideas, pleasures and pains!_'"
Davy aroused the admiration and interest of every one who met him. A
literary man to whom he was introduced shortly after his arrival in
Bristol spoke of the intellectual character of the young man's face. His
eye was piercing, and when he was not engaged in conversation, its
expression indicated abstraction, as though his mind were pursuing some
severe train of thought scarcely to be interrupted by external objects;
"and," this writer adds, "his ingenuousness impressed me as much as his
mental superiority." Mrs. Beddoes, a gay, witty, and elegant lady, and
an ardent admirer of the youthful scientist, was a sister of Maria
Edgeworth. The novelist's tolerance of Davy's enthusiasm soon passed
into a clear recognition of his commanding genius. Coleridge, Southey,
and other congenial friends, whom the chemist met under Dr. Beddoes'
roof, shared in the general admiration of his mental and social
qualities. Southey spoke of him as a miraculous young man, at whose
talents he could only wonder. Coleridge, when asked how Davy compared
with the cleverest men he had met on a visit to London, replied
expressively: "Why, Davy can eat them all! There is an energy, an
elasticity in his mind, which enables him to seize on and analyze all
questions, pushing them to their legitimate consequences. Every subject
in Davy's mind has the principle of vitality. Living thoughts spring up
like turf under his feet." He thought that if Davy had not been the
first chemist he would have been the first poet of the age. Their
correspondence attests the intimate interchange of ideas and sentiments
between these two men of genius, so different, yet with so much in
common.
In 1801 Davy was appointed assistant lecturer in chemistry at the Royal
Institution (Albemarle Street, London), which had been founded from
philanthropic motives by Count Rumford in 1799. Its aim was to promote
the application of science to the common purposes of life. Its founder
desired while benefiting the poor to enlist the sympathies of the
fashionable world. Davy, with a zeal for the cause of humanity and a
clear recognition of the value of a knowledge of chemistry in technical
industries and other daily occupations, lent himself readily to the
founder's plans. His success as a public expositor of science soon won
him promotion to the professorship of chemistry in the new institution,
and through his influence an interest in scientific investigation became
the vogue of London society. His popularity as a lecturer was so great
that his best friends feared that the head of the brilliant provincial
youth of twenty-two might be turned by the adulation of which he soon
became the object. "I have read," writes his brother, "copies of verses
addressed to him then, ... anonymous effusions, some of them displaying
much poetical taste as well as fervor of writing, and all showing the
influence which his appearance and manner had on the more susceptible of
his audience."
His study of the tanning industry (1801-1802) and his lectures on
agricultural chemistry (1803-1813) are indicative of the early purpose
of the Royal Institution and of Davy's lifelong inclination. The focus
of his scientific interest, however, rested on the furtherance of the
application of the electrical studies of Galvani and Volta in chemical
analysis. In a letter to the chairman of managers of the Royal
Institution Volta had in 1800 described his voltaic pile made up of a
succession of zinc and copper plates in pairs separated by a moist
conductor, and before the end of the same year Nicholson and Carlisle
had employed an electric current, produced by this newly devised
apparatus, in the decomposition of water into its elements.
In the spring of the following year the _Philosophical Magazine_ states:
"We have also to notice a course of lectures, just commenced at the
institution, on a new branch of philosophy--we mean Galvanic Phenomena.
On this interesting branch Mr. Davy (late of Bristol) gave the first
lecture on the 25th of April. He began with the history of Galvanism,
detailed the successive discoveries, and described the different methods
of accumulating influence.... He showed the effects of galvanism on the
legs of frogs, and exhibited some interesting experiments on the
galvanic effects on the solutions of metals in acids." In a paper
communicated to the Royal Society in 1806, _On Some Chemical Agencies of
Electricity_, Davy put on record the result of years of experiment. For
example, as stated by his biographer, he had connected a cup of gypsum
with one of agate by means of asbestos, and filling each with purified
water, had inserted the negative wire of the battery in the agate cup,
and the positive wire in that of the sulphate of lime. In about four
hours he had found a strong solution of lime in the agate cup, and
sulphuric acid in the cup of gypsum. On his reversing the arrangement,
and carrying on the process for a similar length of time, the sulphuric
acid appeared in the agate cup, and the solution of lime on the opposite
side. It was thus that he studied the transfer of certain of the
constituent parts of bodies by the action of electricity. "It is very
natural to suppose," says Davy, "that the repellent and attractive
energies are communicated from one particle to another particle of the
same kind, so as to establish a conducting _chain_ in the fluid. There
may be a succession of decompositions and recompositions before the
electrolysis is complete."
The publication of this paper in 1806 attracted much attention abroad,
and gained for him--in spite of the fact that England and France were
then at war--a medal awarded, under an arrangement instituted by
Napoleon a few years previously, for the best experimental work on the
subject of electricity. "Some people," said Davy, "say I ought not to
accept this prize; and there have been foolish paragraphs in the papers
to that effect; but if the two countries or governments are at war, the
men of science are not. That would, indeed, be a civil war of the worst
description: we should rather, through the instrumentality of men of
science, soften the asperities of national hostility."
In the following year Davy reported other chemical changes produced by
electricity; he had succeeded in decomposing the fixed alkalis and
discovering the elements potassium and sodium. To analyze a small piece
of pure potash slightly moist from the atmosphere, he had placed it on
an insulated platinum disk connected with the negative side of a voltaic
battery. A platinum wire connected with the positive side was brought in
contact with the upper surface of the alkali. "The potash began to fuse
at both its points of electrization." At the lower (negative) surface
small globules having a high metallic luster like quicksilver appeared,
some of which burned with explosion and flame while others remained and
became tarnished. When Davy saw these globules of a hitherto unknown
metal, he danced about the laboratory in ecstasy and for some time was
too much excited to continue his experiments.
After recovering from a very severe illness, owing in the judgment of
some to overapplication to experimental science, and in his own judgment
to a visit to Newgate Prison with the purpose of improving its sanitary
condition, Davy made an investigation of the alkaline earths. He failed
in his endeavor to obtain from these sources pure metals, but he gave
names to barium, strontium, calcium, and magnesium, conjecturing that
the alkaline earths were, like potash and soda, metallic oxides. In
addition Davy anticipated the isolation of silicon, aluminium, and
zirconium. No doubt what gave special zest to his study of the alkalis
was the hope of overthrowing the doctrine of French chemists that oxygen
was the essential element of every acid. Lavoisier had given it, indeed,
the name oxygen (acid-producer) on that supposition. Davy showed,
however, that this element is a constituent of many alkalis.
In 1810 he advanced his controversy by explaining the nature of
chlorine. Discovered long before by the indefatigable Scheele, it bore
at the beginning of the nineteenth century the name oxymuriatic acid.
Davy proved that it contained neither oxygen nor muriatic (hydrochloric)
acid (though, as we know, it forms, with hydrogen, muriatic acid). He
gave the name _chlorine_ because of the color of the gas (χλωρός, pale
green). Davy studied later the compounds of fluorine, and though unable
to isolate the element, conjectured its likeness to chlorine.
He lectured before the Dublin Society in 1810, and again in the
following year; on the occasion of his second visit receiving the degree
of LL.D. from Trinity College. He was knighted in the spring of 1812,
and was married to a handsome, intellectual, and wealthy lady. He was
appointed Honorary Professor of Chemistry at the Royal Institution. His
new independence gave him full liberty to pursue his scientific
interests. Toward the close of 1812 he writes to Lady Davy:--
"Yesterday I began some new experiments to which a very interesting
discovery and a slight accident put an end. I made use of a compound
more powerful than gunpowder destined perhaps at some time to change the
nature of war and influence the state of society. An explosion took
place which has done me no other harm than that of preventing me from
working this day and the effects of which will be gone to-morrow and
which I should not mention at all, except that you may hear some foolish
exaggerated account of it, for it really is not worth mentioning...."
The compound on the investigation of which he was then engaged is now
known as the trichloride of nitrogen.
In the autumn of 1813 Sir Humphry and Lady Davy, accompanied by Michael
Faraday, who on Davy's recommendation had in the spring of the same year
received a post at the Royal Institution, set out, in spite of the
continuance of the war, on a Continental tour. At Paris Sir Humphry was
welcomed by the French scientists with every mark of distinction. A
substance which had been found in the ashes of seaweed two years
previously, by a soap-boiler and manufacturer of saltpeter, was
submitted to Davy for chemical examination. Until Davy's arrival in
Paris little had been done to determine its real character. On December
6 Gay-Lussac presented a brief report on the new substance, which he
named _iode_ and considered analogous to chlorine. Davy, working with
almost incredible rapidity in the presence of his rivals, was able a
week later to sketch the chief characters of this new element, now known
by the name he chose for it--_iodine_.
We have passed over his investigation of boracic acid, ammonium nitrate,
and other compounds; we can merely mention in passing his later studies
of the diamond and other forms of carbon, of the chemical constituents
of the pigments used by the ancients, his investigation of the torpedo
fish, and his anticipation of the arc light.
It seems fitting that Sir Humphry Davy should be popularly remembered
for his invention of the miner's safety-lamp. At the beginning of the
nineteenth century the development of the iron industry, the increasing
use of the steam engine and of machinery in general led to great
activity and enterprise in the working of the coal mines. Colliery
explosions of fire-damp (marsh gas) became alarmingly frequent,
especially in the north of England. The mine-owners in some cases sought
to suppress the news of fatalities. A society, however, was formed to
protect the miners from injury through gas explosions, and Davy was
asked for advice. On his return from the Continent in 1815 he applied
himself energetically to the matter. He visited the mines and analyzed
the gas. He found that fire-damp explodes only at high temperature, and
that the flame of this explosive mixture will not pass through small
apertures. A miner's lamp was therefore constructed with wire gauze
about the flame to admit air for combustion. The fire-damp entering the
gauze burned quietly inside, but could not carry a high enough
temperature through the gauze to explode the large quantity outside. To
one of the members of the philanthropic society which had appealed to
him Davy wrote: "I have never received so much pleasure from the result
of any of my chemical labours; for I trust the cause of humanity will
gain something by it."
Davy was elected President of the Royal Society in 1820, and retained
that dignity till he felt compelled by ill health to relinquish it in
1827. "It was his wish," says his brother, "to have seen the Royal
Society an efficient establishment for all the great practical purposes
of science, similar to the college contemplated by Lord Bacon, and
sketched in his _New Atlantis_; having subordinate to it the Royal
Observatory at Greenwich for astronomy; the British Museum, for natural
history, in its most extensive acceptation."
Sir Humphry Davy, after a life crowded with splendid achievements, died
at Geneva in 1829 with many of his noblest dreams unfulfilled.
Fortunately in Michael Faraday, who is sometimes referred to as the
greatest of his discoveries, he had a successor who was fully adequate
to the task of furthering the various investigations that his genius had
set on foot, and who, to the majority of men of mature mind, is no less
personally interesting than the Cornish scientist, poet, and
philosopher.
REFERENCES
John Davy, _Works of Sir Humphry Davy_.
John Davy, _Fragmentary Remains, literary and scientific, of Sir
Humphry Davy, Bart._
Bence Jones, _Life and Letters of Faraday_.
John Tyndall, _Faraday as a Discoverer_.
E. v. Meyer, _History of Chemistry_.
S. P. Thompson, _Michael Faraday; his Life and Work_.
Sir Edward Thorpe, _Humphry Davy, Poet and Philosopher_.
CHAPTER XIV
SCIENTIFIC PREDICTION--THE DISCOVERY OF NEPTUNE
Under this heading we have to consider a single illustration--the
prediction, and the discovery, in 1846, of the planet Neptune. This
event roused great enthusiasm among scientists as well as in the popular
mind, afforded proof of the reliability of the Newtonian hypothesis, and
demonstrated the precision to which the calculation of celestial motions
had attained. Scientific law appeared not merely as a formulation and
explanation of observed phenomena but as a means for the discovery of
new truths. "Would it not be admirable," wrote Valz to Arago in 1835,
"to arrive thus at a knowledge of the existence of a body which cannot
be perceived?"
The prediction and discovery of Neptune, to which many minds
contributed, and which has been described with a show of justice as a
movement of the times, arose from the previous discovery of the planet
Uranus by Sir William Herschel in 1781. After that event Bode suggested
that it was possible other astronomers had observed Uranus before,
without recognizing it as a planet. By a study of the star catalogues
this conjecture was soon verified. It was found that Flamsteed had made,
in 1690, the first observation of the heavenly body now called Uranus.
Ultimately it was shown that there were at least seventeen similar
observations prior to 1781.
It might naturally be supposed that these so-called ancient observations
would lead to a ready determination of the planet's orbit, mass, mean
distance, longitude with reference to the sun, etc. The contrary,
however, seemed to be the case. When Alexis Bouvard, the associate of
Laplace, prepared in 1821 tables of Uranus, Jupiter, and Saturn on the
principles of the _Mécanique Céleste_, he was unable to fix an orbit for
Uranus which would harmonize with the data of ancient and modern
observations, that is, those antecedent and subsequent to Herschel's
discovery in 1781. If he computed an orbit from the two sets of data
combined, the requirements of the earlier observations were fairly well
met, but the later observations were not represented with sufficient
precision. If on the other hand only the modern data were taken into
account, tables could be constructed meeting all the observations
subsequent to 1781, but failing to satisfy those prior to that date. A
consistent result could be obtained only by sacrificing the modern or
the ancient observations. "I have thought it preferable," says Bouvard,
"to abide by the second [alternative], as being that which combines the
greater number of probabilities in favor of the truth, and I leave it to
the future to make known whether the difficulty of reconciling the two
systems result from the inaccuracy of ancient observations, or whether
it depend upon some extraneous and unknown influence, which has acted on
the planet." It was not till three years after the death of Alexis
Bouvard that the extraneous influence, of which he thus gave in 1821
some indication, became fully known.
Almost immediately, however, after the publication of the tables, fresh
discrepancies arose between computation and observation. At the first
meeting of the British Association in 1832 Professor Airy in a paper on
the _Progress of Astronomy_ showed that observational data in reference
to the planet Uranus diverged widely from the tables of 1821. In 1833
through his influence the "reduction of all the planetary observations
made at Greenwich from 1750" was undertaken. Airy became Astronomer
Royal in 1835, and continued to take special interest in Uranus, laying
particular emphasis on the fact that the radius vector assigned in the
tables to this planet was much too small.
In 1834 the Reverend T. J. Hussey, an amateur astronomer, had written to
Airy in reference to the irregularities in the orbit of Uranus: "The
apparently inexplicable discrepancies between the ancient and modern
observations suggested to me the possibility of some disturbing body
beyond Uranus, not taken into account because unknown.... Subsequently,
in conversation with Bouvard, I inquired if the above might not be the
case." Bouvard answered that the idea had occurred to him; indeed, he
had had some correspondence in reference to it in 1829 with Hansen, an
authority on planetary perturbations.
In the following year Nicolai (as well as Valz) was interested in the
problem of an ultra-Uranian planet in connection with the orbit of
Halley's comet (itself the subject of a striking scientific prediction
fulfilled in 1758), now reappearing, and under the disturbing influence
of Jupiter. In fact, the probability of the approaching discovery of a
new planet soon found expression in popular treatises on astronomy. Mrs.
Somerville in her book on _The Connection of the Physical Sciences_
(1836) said that the discrepancies in the records of Uranus might reveal
the existence and even "the mass and orbit of a body placed for ever
beyond the sphere of vision." Similarly Mädler in his _Popular
Astronomy_ (1841) took the view that Uranus might have been predicted by
study of the perturbations it produced in the orbit of Saturn. Applying
this conclusion to a body beyond Uranus we, he continued, "may, indeed,
express the hope that analysis will one day or other solemnize this, her
highest, triumph, making discoveries with the mind's eye in regions
where, in our actual state, we are unable to penetrate."
One should not pass over in this account the labors of Eugène Bouvard,
the nephew of Alexis, who continued to note anomalies in the orbit of
Uranus and to construct new planetary tables till the very eve of the
discovery of Neptune. In 1837 he wrote to Airy that the differences
between the observations of Uranus and the calculation were large and
were becoming continually larger: "Is that owing to a perturbation
brought about in this planet by some body situated beyond it? I don't
know, but that's my uncle's opinion."
In 1840 the distinguished astronomer Bessel declared that attempts to
explain the discrepancies "must be based on the endeavor to discover an
orbit and a mass for some unknown planet, of such a nature, that the
resulting perturbations of Uranus may reconcile the present want of
harmony in the observations." Two years later he undertook researches
in reference to the new planet of whose existence he felt certain. His
labors, however, were interrupted by the death of his assistant
Flemming, and by his own illness, which proved fatal in 1846, a few
months before the actual discovery of Neptune. It is evident that the
quest of the new planet had become general. The error of Uranus still
amounted to less than two minutes. This deviation from the computed
place is not appreciable by the naked eye, yet it was felt, by the
scientific world, to challenge the validity of the Newtonian theory, or
to foreshadow the addition of still another planet to our solar system.
In July, 1841, John Couch Adams, a young undergraduate of St. John's
College, Cambridge, whose interest had been aroused by reading Airy's
paper on the _Progress of Astronomy_, made note of his resolution to
attempt, after completing his college course, the solution of the
problem then forming in so many minds. After achieving the B.A. as
senior wrangler at the beginning of 1843, Adams undertook to "find the
most probable orbit and mass of the disturbing body which has acted on
Uranus." The ordinary problem in planetary perturbations calls for the
determination of the effect on a known orbit exerted by a body of known
mass and motion. This was an inverse problem; the perturbation being
given, it was required to find the position, mass, and orbit of the
disturbing planet. The data were further equivocal in that the
elements of the given planet Uranus were themselves in doubt; the
unreliability of its planetary tables, in fact, being the occasion of
the investigation now undertaken. That thirteen unknown quantities were
involved indicates sufficiently the difficulty of the problem.
Adams started with the assumptions, not improbable, that the orbit of
the unknown planet was a circle, and that its distance from the sun was
twice that of Uranus. This latter assumption was in accord with the
so-called "Bode's Law," which taught that a simple numerical
relationship exists between the planetary distances (4, 7, 10, 16, 28,
52, 100, 196), and that the planets as they lie more remote from the sun
tend to be more nearly double the distance of the next preceding. Adams
was encouraged, by his first attempt, to undertake a more precise
determination.
On his behalf Professor Challis of Cambridge applied to Astronomer Royal
Airy, who furnished the _Reductions of the Planetary Observations_ made
at Greenwich from 1750 till 1830. In his second endeavor Adams assumed
that the unknown planet had an elliptical orbit. He approached the
solution gradually, ever taking into account more terms of the
perturbations. In September, 1845, he gave the results to Challis, who
wrote to Airy on the 22d of that month that Adams sought an opportunity
to submit the solution personally to the Astronomer Royal. On the 21st
of October, 1845, the young mathematician, twice disappointed in his
attempt to meet Airy, left at the Royal Observatory a paper containing
the elements of the new planet. The position assigned to it was within
about one degree of its actual place.
On November 5 Airy wrote to Adams and, among other things, inquired
whether the solution obtained would account for the errors of the
radius vector as well as for those of heliocentric longitude. For Airy
this was a crucial question; but to Adams it seemed unessential, and he
failed to reply.
By this time a formidable rival had entered the field. Leverrier at the
request of Arago had undertaken to investigate the irregularities in the
tables of Uranus. In September of the same year Eugène Bouvard had
presented new tables of that planet. Leverrier acted very promptly and
systematically. His first paper on the problem undertaken appeared in
the _Comptes Rendus_ of the Académie des Sciences November 10, 1845. He
had submitted to rigorous examination the data in reference to the
disturbing influence of Jupiter and of Saturn on the orbit of Uranus. In
his second paper, June 1, 1846, Leverrier reviewed the records of the
ancient and modern observations of Uranus (279 in all), subjected
Bouvard's tables to severe criticism, and decided that there existed in
the orbit of Uranus anomalies that could not be accounted due to errors
of observation. There must exist some extraneous influence, hitherto
unknown to astronomers. Some scientists had thought that the law of
gravitation did not hold at the confines of the solar system (others
that the attractive force of other systems might prove a factor), but
Leverrier rejected this conception. Other theories being likewise
discarded he asked: "Is it possible that the irregularities of Uranus
are due to the action of a disturbing planet, situated in the ecliptic
at a mean distance double that of Uranus? And if so, at what point is
this planet situated? What is its mass? What are the elements of the
orbit which it describes?" The conclusion reached by the calculations
recorded in this second paper was that all the so-called anomalies in
the observations of Uranus could be explained as the perturbation caused
by a planet with a heliocentric longitude of 252° on January 1, 1800.
This would correspond to 325° January 1, 1847.
Airy received Leverrier's second paper on June 23, and was struck by the
fact that the French mathematician assigned the same place to the new
planet as had Adams in the preceding October. He wrote to Leverrier in
reference to the errors of the radius vector and received a satisfactory
and sufficiently compliant reply. At one time the Astronomer Royal had
felt very skeptical about the possibility of the discovery which his own
labors had contributed to advance. He had always, to quote his own
rather nebulous statement, considered the correctness of a distant
mathematical result to be the subject of moral rather than of
mathematical evidence. Now that corroboration of Adams's results had
arrived, he felt it urgent to make a telescopic examination of that part
of the heavens indicated by the theoretical findings of Adams and
Leverrier. He accordingly wrote to Professor Challis, July 9, requesting
him to employ for the purpose the great Northumberland equatorial of the
Cambridge Observatory.
Professor Challis had felt, to use his own language, that it was so
novel a thing to undertake observations in reliance upon merely
theoretical deductions, that, while much labor was certain, success
appeared very doubtful. Nevertheless, having received fresh instructions
from Adams relative to the theoretical place of the new planet, he
began observations July 29. On August 4 in fixing certain reference
points he noted, but mistook for a star, the new planet. On August 12,
having directed the telescope in accordance with Adams's instructions he
again noted the same heavenly body, as a star. Before Challis had
compared the results of the observation of August 12 with the results of
an observation of the same region made on July 30, and arrived at the
inference that the body in question, being absent in the latter
observation, was not a star but a planet, the prize of discovery had
fallen into the hands of another observer.
On August 31 had appeared Leverrier's third paper, in which were stated
the new planet's orbit, mass, distance from the sun, eccentricity, and
longitude. The true heliocentric longitude was given as 326° 32' for
January 1, 1847. This determination placed the planet about 5° to the
east of star δ of Capricorn. Leverrier said it might be recognized by
its disk, which, moreover, would subtend a certain angle.
The systematic and conclusive character of Leverrier's research,
submitted to one of the greatest academies of science, carried
conviction to the minds of astronomers. The learned world felt itself on
the eve of a great discovery. Sir John Herschel, in an address before
the British Association on September 10, said that the year past had
given prospect of a new planet. "We see it as Columbus saw America from
the shores of Spain. Its movements have been felt trembling along the
far-reaching line of our analysis with a certainty hardly inferior to
ocular demonstration."
On September 18 Leverrier sent a letter to Dr. Galle, of the Berlin
Observatory, which was provided with a set of star maps, prepared at the
instance of Bessel. Galle replied one week later. "The planet, of the
position of which you gave the indication, really exists. The same day
that I received your letter [September 23] I found a star of the eighth
magnitude, which was not inscribed in the excellent map (prepared by Dr.
Bremiker) belonging to the collection of star maps of the Royal Academy
of Berlin. The observation of the following day showed decisively that
it was the planet sought." It was only 57' from the point predicted.
Arago said that the discovery made by Leverrier was one of the most
brilliant manifestations of the precision of modern astronomic science.
It would encourage the best geometers to seek with renewed ardor the
eternal truths which, in Pliny's phrase, are latent in the majesty of
theory.
Professor Challis received Leverrier's third paper on September 29, and
in the evening turned his magnificent refractor to the part of the
heavens that Leverrier had so definitely and so confidently indicated.
Among the three hundred stars observed Challis was struck by the
appearance of one which presented a disk and shone with the brightness
of a star of the eighth magnitude. This proved to be the planet. On
October 1 Challis heard that the German observer had anticipated him.
Arago, while recognizing the excellent work done by Adams in his
calculations, thought that the fact that the young mathematician had
failed to publish his results should deprive him of any share whatever
in the glory of the discovery of the new planet, and that history would
confirm this definite judgment. Arago named the new planet after the
French discoverer, but soon acquiesced in the name Neptune, which has
since prevailed.
Airy, in whose possession Adams's results had remained for months
unpublished and unheeded, wrote Leverrier: "You are to be recognized
beyond doubt as the predictor of the planet's place." A vigorous
official himself, Airy was deeply impressed by the calm decisiveness and
definite directions of the French mathematician. "It is here, if I
mistake not, that we see a character far superior to that of the able,
or enterprising, or industrious mathematician; it is here that we see
the philosopher." This explains, if anything could, his view that a
distant mathematical result is the subject of ethical rather than of
mathematical evidence.
Adams's friends felt that he had not received from either of the
astronomers, to whom he confided his results, the kind of help or advice
he should have received. Challis was kindly, but wanting in initiative.
Although he had command of the great Northumberland telescope, he had no
thought of commencing the search in 1845, for, without mistrusting the
evidence which the theory gave of the _existence_ of the planet, it
might be reasonable to suppose that its position was determined but
roughly, and that a search for it must necessarily be long and
laborious. In the view of Simon Newcomb,[3] Adams's results, which were
delivered at the Greenwich Observatory October 21, 1845, were so near to
the mark that a few hours' close search could not have failed to make
the planet known.
Both Adams and Leverrier had assumed as a rough approximation at
starting that the orbit of the new planet was circular and that, in
accordance with Bode's Law, its distance was twice that of Uranus. S. C.
Walker, of the Smithsonian Institution, Washington, was able to
determine the elements of the orbit of Neptune accurately in 1847. In
February of that year he had found (as had Petersen of Altona about the
same time) that Lalande had in May, 1795, observed Neptune and mistaken
it for a fixed star. When Lalande's records in Paris were studied, it
was found that he had made two observations of Neptune on May 8 and 10.
Their failure to agree caused the observer to reject one and mark the
other as doubtful. Had he repeated the observation, he might have noted
that the _star_ moved, and was in reality a planet.
Neptune's orbit is more nearly circular than that of any of the major
planets except Venus. Its distance is thirty times that of the earth
from the sun instead of thirty-nine times, as Bode's Law would require.
That generalization was a presupposition of the calculations leading to
the discovery. It was then rejected like a discredited ladder. Man's
conception of the universe is widened at the thought that the outmost
known planet of our solar system is about 2,796,000,000 miles from the
sun and requires about 165 years for one revolution.
Professor Peirce, of Harvard University, pointing to the difference
between the calculations of Leverrier and the facts, put forward the
view that the discovery made by Galle must be regarded as a happy
accident. This view, however, has not been sustained.
REFERENCES
Sir Robert Ball, Neptune's Jubilee Year, _Scientific American_,
Supplement, Oct. 10, 1896.
Sir Robert Ball, _The Story of the Heavens_, chap. XV.
B. A. Gould, _Report on the History of the Discovery of Neptune,
Smithsonian Contributions to Knowledge_, 1850.
Robert Grant, _History of Physical Astronomy_.
Simon Newcomb, _Popular Astronomy_.
Benjamin Peirce, _Proceedings of the American Academy of Arts and
Sciences_, vol. I, pp. 57-68, 144, 285, 338-41, etc.
FOOTNOTES:
[3] See article "Neptune," _Encyc. Brit._
CHAPTER XV
SCIENCE AND TRAVEL--THE VOYAGE OF THE BEAGLE
Sir Charles Lyell, in his _Principles of Geology_, the first edition of
which appeared in 1830-1833, says: "If it be true that delivery be the
first, second, and third requisite in a popular orator, it is no less
certain that travel is of first, second, and third importance to those
who desire to originate just and comprehensive views concerning the
structure of our globe." The value of travel to science in general might
very well be illustrated by Lyell's own career, his study of the
mountainous regions of France, his calculation of the recession of
Niagara Falls and of the sedimentary deposits of the Mississippi, his
observations of the coal formations of Nova Scotia, and of the
composition of the Great Dismal Swamp of Virginia--suggestive of the
organic origin of the carboniferous rocks.
Although it is not with Lyell that we have here principally to deal, it
is not irrelevant to say that the main purpose of his work was to show
that all past changes in the earth's crust are referable to causes now
in operation. Differing from Hutton as to the part played in those
changes by subterranean heat, Lyell agreed with his forerunner in
ascribing geological transformations to "the slow agency of existing
causes." He was, in fact, the leader of the uniformitarians and opposed
those geologists who held that the contemporary state of the earth's
crust was owing to a series of catastrophes, stupendous exhibitions of
natural force to which recent history offered no parallel. Also
enlightened as to the significance of organic remains in stratified
rock, Lyell in 1830 felt the need of further knowledge in reference to
the relation of the plants and animals represented in the fossils to the
fauna and flora now existing.
It is to Lyell's disciple, Charles Darwin, however, that we turn for our
main illustration of the value of travel for comprehensive scientific
generalization. Born, like another great liberator, on February 12,
1809, Darwin was only twenty-two years old when he received appointment
as naturalist on H.M.S. Beagle, about to sail from Devonport on a voyage
around the world. The main purpose of the expedition, under command of
the youthful Captain Fitzroy, three or four years older than Darwin, was
to make a survey of certain coasts in South America and the Pacific
Islands, and to carry a line of chronometrical measurements about the
globe. Looking back in 1876 on this memorable expedition, the naturalist
wrote, "The voyage of the Beagle has been by far the most important
event in my life, and has determined my whole career." In spite of the
years he had spent at school and college he regarded this experience as
the first real training or education of his mind.
Darwin had studied medicine at Edinburgh, but found surgery distasteful.
He moved to Cambridge, with the idea of becoming a clergyman of the
Established Church. As a boy he had attended with his mother, daughter
of Josiah Wedgwood, the Unitarian services. At Cambridge he graduated
without distinction at the beginning of 1831. It should be said,
however, that the traditional studies were particularly ill suited to
his cast of mind, that he had not been idle, and had developed
particular diligence in different branches of science, and above all as
a collector.
He was six feet tall, fond of shooting and hunting, and able to ride
seventy-five or eighty miles without tiring. He had shown himself at
college fond of company, and a little extravagant. He was, though a
sportsman, extremely humane; had a horror of inflicting pain, and such
repugnance at the thought of slavery that he quarreled violently with
Captain Fitzroy when the latter condoned the abomination. Darwin was
not, however, of a turbulent disposition. Sir James Sulivan, who had
accompanied the expedition as second lieutenant, said many years after:
"I can confidently express my belief that during the five years in the
Beagle, he was never known to be out of temper, or to say one unkind or
hasty word _of_ or _to_ any one."
Darwin's father was remarkable for his powers of observation, while the
grandfather, Erasmus Darwin, is well known for his tendency to
speculation. Charles Darwin possessed both these mental characteristics
in an eminent degree. One who has conversed with him reports that what
impressed him most in meeting the great naturalist was his clear blue
eyes, which seemed to possess almost telescopic vision, and that the
really remarkable thing about Darwin was that he saw more than other
people. At the same time it will scarcely be denied that his vision was
as much marked by insight as by careful observation, that his reasoning
was logical and singularly tenacious, and his imagination vivid. It was
before this supreme seer that the panorama of terrestrial creation was
displayed during a five years' voyage.
No one can read Darwin's _Journal_ descriptive of the voyage of the
Beagle and continue to entertain any doubts in reference to his æsthetic
sense and poetic appreciation of the various moods of nature. Throughout
the voyage the scenery was for him the most constant and highest source
of enjoyment. His emotions responded to the glories of tropical
vegetation in the Brazilian forests, and to the sublimity of Patagonian
wastes and the forest-clad hills of Tierra del Fuego. "It is easy,"
writes the gifted adolescent, "to specify the individual objects of
admiration in these grand scenes; but it is not possible to give an
adequate idea of the higher feelings of wonder, astonishment, and
devotion, which fill and elevate the mind." Similarly, on the heights of
the Andes, listening to the stones borne seaward day and night by the
mountain torrents, Darwin remarked: "The sound spoke eloquently to the
geologist; the thousands and thousands of stones, which striking against
each other, made the one dull uniform sound, were all hurrying in one
direction. It was like thinking on time, where the minute that now
glides past is irrecoverable. So was it with these stones, the ocean is
their eternity, and each note of that wild music told of one more step
towards their destiny."
When the Beagle left Devonport, December 27, 1831, the young naturalist
was without any theory, and when the ship entered Falmouth harbor,
October 2, 1836, though he felt the need of a theory in reference to the
relations of the various species of plants and animals, he had not
formulated one. It was not till 1859 that his famous work on the _Origin
of Species_ appeared. He went merely as a collector, and frequently in
the course of the voyage felt a young man's misgivings as to whether his
collections would be of value to his Cambridge professors and other
mature scientists.
Professor Henslow, the botanist, through whom Darwin had been offered
the opportunity to accompany the expedition, had presented his pupil
with the first volume of Lyell's _Principles of Geology_. (Perhaps,
after Lyell, the most potent influence on Darwin's mind at this time was
that of Humboldt and other renowned travelers, whose works he read with
avidity.) At the Cape Verde Islands he made some interesting
observations of a white calcareous stratum which ran for miles along the
coast at a height of about forty-five feet above the water. It rested on
volcanic rocks and was itself covered with basalt, that is, lava which
had crystallized under the sea. It was evident that subsequently to the
formation of the basalt that portion of the coast containing the white
stratum had been elevated. The shells in the stratum were recent, that
is, corresponded to those still to be found on the neighboring coast. It
occurred to Darwin that the voyage might afford material for a book on
geology. Later in the voyage, having read portions of his _Journal_ to
Captain Fitzroy, Darwin was encouraged to believe that this also might
prove worthy of publication.
Darwin's account of his adventures and manifold observations is so
informal, so rich in detail, as not to admit of summary. His eye took in
the most diverse phenomena, the color of the sea or of rivers, clouds of
butterflies and of locusts, the cacique with his little boy clinging to
the side of a horse in headlong flight, the great earthquake on the
coast of Chile, the endless variety of plant and animal life, the
superstition of savage and _padre_, the charms of Tahiti, the
unconscious humor of his mountain guides for whom at an altitude of
eleven thousand feet "the cursed pot (which was a new one) did not
choose to boil potatoes"--all found response in Darwin's open mind;
everything was grist to his mill. Any selection from the richness of the
original is almost sure to show a tendency not obvious in the _Journal_.
On the other hand, it is just such multiplicity of phenomena as the
_Journal_ mirrors that impels every orderly mind to seek for causes, for
explanation. The human intellect cannot rest till law gives form to the
wild chaos of fact.
No disciple of Lyell could fail to be convinced of the immeasurable
lapse of time required for the formation of the earth's crust. For this
principle Darwin found abundant evidence during the years spent in South
America. On the heights of the Andes he found marine shell fossils at a
height of fourteen thousand feet above sea-level. That such an elevation
of submarine strata should be achieved by forces still at Nature's
command might well test the faith of the most ardent disciple. Of how
great those forces are Darwin received demonstration on the coast of
Chile in 1835. Under date of February 12, he writes: "This day has been
memorable in the annals of Valdivia for the most severe earthquake
experienced by the oldest inhabitant.... A bad earthquake destroys our
oldest associations; the earth, the very emblem of solidity, has moved
beneath our feet like a thin crust over a fluid." He observed that the
most remarkable effect of this earthquake was the permanent elevation of
the land. Around the Bay of Concepcion it was raised two or three feet,
while at the island of Santa Maria the elevation was much greater; "on
one part Captain Fitzroy found beds of putrid mussel shells _still
adhering to the rocks_, ten feet above high-water mark." On the same day
the volcanoes of South America were active. The area from under which
volcanic matter was actually erupted was 720 miles in one line and 400
in another at right angles to it. Great as is the force at work, ages
are required to produce a range of mountains like the Cordilleras;
moreover, progress is not uniform and subsidence may alternate with
elevation. It was on the principle of the gradual subsidence (and
elevation) of the bed of the Pacific Ocean that Darwin accounted for the
formation of coral reefs. Nothing "is so unstable as the level of the
crust of this earth."
Closely associated with the evidence of the immensity of the force of
volcanic action and the infinitude of time elapsed, Darwin had testimony
of the multitude of plant and animal species, some gigantic, others
almost infinitely small, some living, others extinct. We know that his
thought was greatly affected by his discovery in Uruguay and Patagonia
of the fossil remains of extinct mammals, all the more so because they
seemed to bear relationship to particular living species and at the same
time to show likeness to other species. The Toxodon (bow-tooth), for
example, was a gigantic rodent whose fossil remains were discovered in
the same region where Darwin found living the capybara, a rodent as
large as a pig; at the same time the extinct species showed in its
structure certain affinities to the Edentata (sloths, ant-eaters,
armadillos). Other fossils represented gigantic forms distinctly of
the edentate order and comparable to the Cape ant-eater and the
Great Armadillo (_Dasypus gigas_). Again, remains were found of a
thick-skinned non-ruminant with certain structural likeness to the
Camelidæ, to which the living species of South American ruminants, the
_guanacos_, belong.
Why have certain species ceased to exist? As the individual sickens and
dies, so certain species become rare and extinct. Darwin found in
Northern Patagonia evidence of the _Equus curvidens_, an extinct species
of native American horse. What had caused this species to die out?
Imported horses were introduced at Buenos Ayres in 1537, and so
flourished in the wild state that in 1580 they were found as far
south as the Strait of Magellan. Darwin was well fitted by the
comprehensiveness of his observations to deal with the various factors
of extinction and survival. He studied the species in their natural
setting, the habitat, and range, and habits, and food of the different
varieties. Traveling for three years and a half north and south on the
continent of South America, he noticed one species replacing another,
perhaps closely allied, species. Of the carrion-feeding hawks the condor
has an immense range, but shows a predilection for perpendicular cliffs.
If an animal die on the plain the polyborus has prerogative of feeding
first, and is followed by the turkey buzzard and the gallinazo. European
horses and cattle running wild in the Falkland Islands are somewhat
modified; the horse as a species degenerating, the cattle increasing in
size and tending to form varieties of different color. The soil being
soft the hoofs of the horse grow long and produce lameness. Again, on
the mainland, the niata, a breed of cattle supposed to have originated
among the Indians south of the Plata, are, on account of the projection
of the lower jaw, unable to browse as effectually as other breeds. This
renders them liable to destruction in times of drought. A similar
variation in structure had characterized a species of extinct ruminant
in India.
How disastrous a great drought might prove to the cattle of the Pampas
is shown by the records of 1825 and of 1830. So little rain fell that
there was a complete failure of vegetation. The loss of cattle in one
province alone was estimated at one million. Of one particular herd of
twenty thousand not a single one survived. Darwin had many other
instances of nature's devastations. After the Beagle sailed from the
Plata, December 6, 1833, vast numbers of butterflies were seen as far as
the eye could range in bands of countless myriads. "Before sunset a
strong breeze sprung up from the north, and this must have caused tens
of thousands of the butterflies and other insects to perish." Two or
three months before this he had ocular proof of the effect of a
hailstorm, which in a very limited area killed twenty deer, fifteen
ostriches, numbers of ducks, hawks, and partridges. In the war of
extermination that was ever before the great naturalist's eye in South
America, what is it that favors a species' survival or determines its
extinction?
Not only is the struggle between the animals and inanimate nature, the
plants and inanimate nature, plant and animal, rival animals, and rival
plants; it goes on between man and his environment, and, very fiercely,
between man and man. Darwin was moved by intense indignation at the
slavery on the east coast and the cruel oppression of the laborer on the
west coast. He was in close contact with the sanguinary political
struggles of South America, and with a war of attempted extermination
against the Indian. He refers to the shocking but "unquestionable fact,
that [in the latter struggle] all the women who appear above twenty
years old are massacred in cold blood! When I exclaimed that this
appeared rather inhuman, he [the informant] answered, 'Why, what can be
done? they breed so!'"
In all his travels nothing that Darwin beheld made a deeper impression
on his sensitive mind than primitive man. "Of individual objects,
perhaps nothing is more certain to create astonishment than the first
sight in his native haunt of a barbarian--of man in his lowest and most
savage state. One's mind hurries back over past centuries, and then
asks, could our progenitors have been men like these?... I do not
believe it is possible to describe or paint the difference between
savage and civilized man." It was at Tierra del Fuego that he was
particularly shocked. He admired the Tahitians; he pitied the natives of
Tasmania, corralled like wild animals and forced to migrate; he thought
the black aborigines of Australia had been underestimated and remarked
with regret that their numbers were decreasing through their association
with civilized man, the introduction of spirits, the increased
difficulty of procuring food, and contact with European diseases. In
this last cause tending to bring about extinction there was a mysterious
element. In Chile his scientific acumen had been baffled in the attempt
to explain the invasion of the strange and dreadful disease hydrophobia.
In Australia the problem of the transmission to the natives of various
diseases, even by Europeans in apparent health, confronted his
intelligence. "The varieties of man seem to act on each other in the
same way as different specimens of animals--the stronger always
extirpating the weaker."
It was at Wollaston Island, near Cape Horn, however, that Darwin saw
savage men held in extremity by the hard conditions of life, and at bay.
They had neither food, nor shelter, nor clothing. They stood absolutely
naked as the sleet fell on them and melted. At night, "naked and
scarcely protected from the wind and rain of this tempestuous climate,"
they slept on the wet ground coiled up like animals. They subsisted on
shell fish, putrid whale's blubber, or a few tasteless berries and
fungi. At war, the different tribes are cannibals. Darwin writes, "It is
certainly true, that when pressed in winter by hunger, they kill and
devour their old women before they kill their dogs." A native boy, when
asked by a traveler why they do this, had answered, "Doggies
catch otters, old women no." In such hard conditions what are the
characteristics that would determine the survival of individual or
tribe? One might be tempted to lay almost exclusive emphasis on physical
strength, but Darwin was too wise ultimately to answer thus the
question that for six or seven years was forming in his accurate and
discriminating mind.
On its way west in the Pacific the Beagle spent a month at the Galapagos
Archipelago, which lies under the equator five or six hundred miles from
the mainland. "Most of the organic productions are aboriginal creations,
found nowhere else; there is even a difference between the inhabitants
of the different islands; yet all show a marked relationship with those
of America." Why should the plants and animals of the islands resemble
those of the mainland, or the inhabitants of one island differ from
those of a neighboring island? Darwin had always held that species were
created immutable, and that it was impossible for one species to give
rise to another.
In the Galapagos Archipelago he found only one species of terrestrial
mammal, a new species of mouse, and that only on the most easterly
island of the group. On the South American continent there were at least
forty species of mice, those east of the Andes being distinct from those
on the west coast. Of land-birds he obtained twenty-six kinds,
twenty-five of which were to be found nowhere else. Among these, a hawk
seemed in structure intermediate between the buzzard and polyborus, as
though it had been modified and induced to take over the functions of
the South American carrion-hawk. There were three species of
mocking-thrush, two of them confined to one island each. There were
thirteen species of finches, all peculiar to the archipelago. In the
different species of geospiza there is a perfect gradation in the size
of the beaks, only to be appreciated by seeing the specimens or their
illustrations.
Few of the birds were of brilliant coloration. The same was true of the
plants and insects. Darwin looked in vain for one brilliant flower. This
was in marked contrast to the fauna and flora of the South American
tropics. The coloration of the species suggested comparison with that of
the plants and animals of Patagonia. Amid brilliant tropical plants
brilliant plumage may afford means of concealment, as well as being a
factor in the securing of mates.
Darwin found the reptiles the most striking feature of the zoölogy of
the islands. They seem to take the place of the herbivorous mammalia.
The huge tortoise (_Testudo nigra_) native in the archipelago is so
heavy as to be lifted only by six or eight men. (The young naturalist
frequently got on the back of a tortoise, but as it moved forward under
his encouragement, he found it very difficult to keep his balance.)
Different varieties, if not species, characterize the different islands.
Of the other reptilia should be noted two species of lizard of a genus
(_Amblyrhynchus_) confined to the Galapagos Islands. One, aquatic, a
yard long, fifteen pounds in weight, with "limbs and strong claws
admirably adapted for crawling over the rugged and fissured masses of
lava," feeds on seaweed. When frightened it instinctively shuns the
water, as though it feared especially its aquatic enemies. The
terrestrial species is confined to the central part of the group; it is
smaller than the aquatic species, and feeds on cactus, leaves of trees,
and berries.
Fifteen new species of sea-fish were obtained, distributed in twelve
genera. The archipelago, though not rich in insects, afforded several
new genera, each island with its distinct kinds. The flora of the
Galapagos Islands proved equally distinctive. More than half of the
flowering plants are native, and the species of the different islands
show wonderful differences. For example, of seventy-one species found on
James Island thirty-eight are confined to the archipelago and thirty to
this one island.
In October the Beagle sailed west to Tahiti, New Zealand, Australia,
Keeling or Cocos Islands, Mauritius, St. Helena, Ascension; arrived at
Bahia, Brazil, August 1, 1836; and finally proceeded from Brazil to
England. Among his many observations, Darwin noted the peculiar
animals of Australia, the kangaroo-rat, and "several of the famous
_Ornithorhynchus paradoxus_," or duckbill. On the Keeling or Cocos
Islands the chief vegetable production is the cocoanut. Here Darwin
observed crabs of monstrous size, with a structure which enabled them to
open the cocoanuts. They thus secured their food, and accumulated
"surprising quantities of the picked fibres of the cocoanut husk, on
which they rest as a bed."
In preparing his _Journal_ for publication in the autumn of 1836 the
young naturalist saw how many facts pointed to the common descent of
species. He thought that by collecting all facts that bore on the
variation of plants and animals, wild or domesticated, light might be
thrown on the whole subject. "I worked on true Baconian principles, and,
without any theory, collected facts on a wholesale scale." He saw that
pigeon-fanciers and stock-breeders develop certain types by preserving
those variations that have the desired characteristics. This is a
process of artificial selection. How is selection made by Nature?
In 1838 he read Malthus' _Essay on the Principle of Population_, which
showed how great and rapid, without checks like war and disease, the
increase in number of the human race would be. He had seen something in
his travels of rivalry for the means of subsistence. He now perceived
"that under these circumstances favorable variations would tend to be
preserved, and unfavorable ones to be destroyed. The results of this
would be the formation of a new species." As special breeds are
developed by artificial selection, so new species evolve by a process of
natural selection. Those genera survive which give rise to species
adapted to new conditions of existence.
In 1858, before Darwin had published his theory, he received from
another great traveler, Alfred Russel Wallace, then at Ternate in the
Moluccas, a manuscript essay, setting forth an almost identical view of
the development of new species through the survival of the fittest in
the struggle for existence.
REFERENCES
Charles Darwin, _A Naturalist's Journal_.
Francis Darwin, _The Life and Letters of Charles Darwin_.
W. A. Locy, _Biology and its Makers_ (third revised edition), chap.
XIX.
G. J. Romanes, _Darwin and After Darwin_, vol. I.
A. R. Wallace, _Darwinism_.
See also John W. Judd, _The Coming of Evolution_ (The Cambridge Manuals
of Science and Literature).
CHAPTER XVI
SCIENCE AND WAR--PASTEUR, LISTER
In the history of science war is no mere interruption, but a great
stimulating influence, promoting directly or indirectly the liberties of
the people, calling into play the energy of artisan and manufacturer,
and increasing the demand for useful and practical studies. In the
activities of naval and military equipment and organization this
influence is obvious enough; it is no less real in the reaction from war
which impels all to turn with new zest to the arts and industries of
peace and to cherish whatever may tend to culture and civil progress.
Not infrequently war gives rise, not only to new educational ideals, but
to new institutions and to new types of institution favorable to the
advancement of science. As we have already seen, the Royal Society and
Milton's Academies owed their origin to the Great Rebellion. Similarly
the Ecole Polytechnique, mother of many scientific discoveries, rose in
answer to the needs of the French Revolution. No less noteworthy was the
reconstruction of education under the practical genius of Napoleon I,
the division of France into académies, the founding of the lycées, the
reëstablishment of the great Ecole Normale, and the organization of the
Imperial University with new science courses and new provincial
Faculties at Rennes, Lille, and elsewhere. With all these different
forms in which the influence of war makes itself felt in the progress of
science the life and career of Louis Pasteur (1822-1895), the founder
of bacteriology, stood intimately associated.
He was born at Dôle, but the family a few years later settled at Arbois.
For three generations the Pasteurs had been tanners in the Jura, and
they naturally adhered to that portion of the population which hailed
the Revolution as a deliverance. The great-grandfather was the first
freeman of Pasteur's forbears, having purchased with money his
emancipation from serfdom. The father in 1811, at the age of twenty, was
one of Napoleon's conscripts, and in 1814 received from the Emperor, for
valor and fidelity, the Cross of the Legion of Honor. The directness and
endurance of the influence of this trained veteran on his gifted son a
hundred fine incidents attest. In 1848--year of revolt in the monarchies
of Europe--the young scientist enrolled himself in the National Guard,
and, seeing one day in the Place du Panthéon a structure inscribed with
the words _autel de la patrie_, he placed upon it all the humble
means--one hundred and fifty francs--then at his disposal.
It was in that same year that Pasteur put on record his discovery of the
nature of racemic acid, his first great service to science, from which
all his other services were to proceed. As a boy he had attended the
_collège_ at Arbois where his teacher had inspired him with an ambition
to enter the great Ecole Normale. Before reaching that goal he took his
bachelor's degree in science as well as in arts at the Besançon college.
At Paris he came in contact with the leaders of the scientific
world--Claude Bernard, Balard, Dumas, Biot.
J. B. Biot had entered the ranks of science by way of the Ecole
Polytechnique and the artillery service. In 1819 he had announced that
the plane of polarized light--for example, a ray passed through Iceland
spar--is deflected to right or left by various chemical substances.
Among these is common tartaric acid--the acid of grape-juice, obtained
from wine lees. Racemic acid, however, which is identical with tartaric
acid in its chemical constituents, is optically inactive, rotating the
plane of polarized light neither to the right nor the left. This
substance Pasteur subjected to special investigation. He scrutinized the
crystals of sodium ammonium racemate obtained from aqueous solution.
These he observed to be of two kinds differing in form as a right glove
from a left, or as an object from its mirror-image. Separating the
crystals according to the difference of form, he made a solution from
each group. One solution, tested in the polarized-light apparatus,
turned the plane to the right; the other solution turned it to the left.
He had made a capital discovery of far-reaching importance, namely, that
racemic acid is composite, consisting of dextro-tartaric and
lævo-tartaric acids. Biot hesitated to credit a mere tyro with such an
achievement. The experiment was repeated in his presence. Convinced by
ocular demonstration, he was almost overcome with emotion. "My dear
boy," he exclaimed, "I have loved the sciences so much my life through
that that makes my heart jump."
Pasteur began his regular professional experience as a teacher of
physics in the Dijon lycée, but he was soon transferred to the
University of Strasburg (1849). There he married the daughter of the
rector of the académie, and three years later became Professor of
Chemistry. In 1854 he was appointed Dean of the Faculty of Sciences at
Lille, a town then officially described as the richest center of
industrial activity in the north of France. In his opening address he
showed the value and attractiveness of practical studies. He believed as
an educator in the close alliance of laboratory and factory. Application
should always be the aim, but resting on the severe and solid basis of
scientific principles; for it is theory alone which can bring forth and
develop the spirit of invention.
His own study of racemic acid, begun in the laboratories of Paris, and
followed up in the factories of Leipzig, Prag, and Vienna, had led to
his theory of molecular dissymmetry, the starting point of modern
stereo-chemistry. It now gave rise on Pasteur's part to new studies and
to new applications to the industries. He tried an experiment which
seems almost whimsical, placing ammonium racemate in the ordinary
conditions of fermentation, and observed that only one part--the
dextro-rotatory--ferments or putrefies. Why? "Because the ferments of
that fermentation feed more easily on the right hand than on the left
hand molecules." He succeeded in keeping alive one of the commonest
moulds on the surface of ashes and racemic acid, and saw the
lævo-tartaric acid appear. It was thus that he passed from the study of
crystals to the study of ferments.
In the middle of the nineteenth century little was known of the nature
of fermentation, though some sought to explain by this ill-understood
process the origin of various diseases and of putrefaction. Why does
fruit-juice produce alcohol, wine turn to vinegar, milk become sour, and
butter rancid? Pasteur's interest in these problems of fermentation was
stimulated by one of the industries of Lille. He was accustomed to visit
with his students the factories of that place as well as those of
neighboring French and Belgian cities. The father of one of his students
was engaged in the manufacture of alcohol from beetroot sugar,
and Pasteur came to be consulted when difficulties arose in the
manufacturing process. He discovered a relationship between the
development of the yeast and the success or failure of the fermentation,
the yeast globules as seen under the microscope showing an alteration of
form when the fermentation was not proceeding satisfactorily. In 1857
Pasteur on the basis of this study was able to demonstrate that
alcoholic fermentation, that is, the conversion of sugar into alcohol,
carbonic acid, and other compounds, depends on the action of yeast, the
cells of which are widely disseminated in the atmosphere.
In this year of his second great triumph Pasteur was appointed director
of science studies in the Ecole Normale, from which he had graduated in
1847. Two years later the loss of his daughter by a communicable
disease--typhoid fever--had a great effect on his sensitive and profound
mind. Many of his opponents, it is true, found Pasteur implacable in
controversy. Undoubtedly he had the courage of his convictions, and his
belief that, for the sake of human welfare, right views--_his_ views won
by tireless experiment--must prevail, gained him the name of a fighter.
But in all the intimate relations of life his essential tenderness was
manifest. Like Darwin he had a horror of inflicting pain, and always
insisted, when operations on animals were necessary in the laboratory,
on the use of anæsthetics (our command of which had been greatly
advanced by Simpson in 1847). Emile Roux said that Pasteur's agitation
at witnessing the slightest exhibition of pain would have been ludicrous
if, in so great a man, it had not been touching.
A few months after his daughter's death Pasteur wrote to one of his
friends: "I am pursuing as best I can these studies on fermentation,
which are of great interest, connected as they are with the impenetrable
mystery of life and death. I am hoping to make a decisive advance very
soon, by solving without the least lack of clearness the famous question
of spontaneous generation." Two years previously a scientist had claimed
that animals and plants could be generated in a medium of artificial air
or oxygen, from which all atmospheric air and all germs of organized
bodies had been precluded. Pasteur now filtered atmospheric air through
a plug of cotton or asbestos (a procedure which had been followed by
others in 1854), and proved that in air thus treated no fermentation
takes place. Nothing in the atmosphere causes life except the
micro-organisms it contains. He even demonstrated that a putrescible
fluid like blood will remain unchanged in an open vessel so constructed
as to exclude atmospheric dust.
Pasteur's critics maintained that if putrefaction and fermentation be
caused solely by microscopic organisms, then these must be found
everywhere and in such quantities as to encumber the air. He replied
that they were less numerous in some parts of the atmosphere than in
others. To prove his contention he set out for Arbois with a large
number of glass bulbs each half filled with a putrescible liquid. The
necks of the bulbs had been drawn out and hermetically sealed after the
contents had been boiled. In case the necks were broken (to be again
sealed immediately), the air would rush in, and (if it held the
requisite micro-organisms) furnish the conditions for putrefaction. It
was found that in every trial the contents of a certain number of the
bulbs always escaped alteration. Twenty were opened in the country near
Arbois free from human habitations. Eight out of the twenty showed signs
of putrefaction. Twenty were exposed to the air on the heights of the
Jura at an altitude of eight hundred and fifty meters above sea-level;
the contents of five of these subsequently putrefied. Twenty others were
opened near Mont Blanc at an altitude of two thousand meters and while a
wind was blowing from the Mer de Glace; in this case the contents of
only one of the bulbs became putrefied.
While his opponents still professed to believe in the creation of
organized beings lacking parents, Pasteur was under the influence of the
theory of "the slow and progressive transformation of one species into
another," and was becoming aware of phases of the struggle for existence
hitherto shrouded in mystery. He wished he said to push these studies
far enough to prepare the way for a serious investigation of the origin
of disease.
He returned to the study of lactic fermentation, showed that butyric
fermentation may be caused by organisms which live in the absence of
oxygen, while vinegar is produced from wine through the agency of
bacteria freely supplied with the oxygen of the air. Pasteur was seeing
ever more clearly the part played by the infinitesimally small in the
economy of nature. Without these microscopic beings life would become
impossible, because death would be incomplete. On the basis of Pasteur's
study of fermentation, his demonstration that decomposition is owing to
living organisms and that minute forms of life spring from parents like
themselves, his disciple Joseph Lister began in 1864 to develop
antiseptic surgery.
Pasteur's attention was next directed to the wine industry, which then
had an annual value to France of 500,000,000 francs. Might not the
acidity, bitterness, defective flavor, which were threatening the
foreign sale of French wines, be owing to ferments? He discovered that
this was, indeed, the case, and that the diseases of wine could be cured
by the simple expedient of heating the liquor for a few moments to a
temperature of 50° to 60° C. Tests on a considerable scale were made by
order of the naval authorities. The ship Jean Bart before starting on a
voyage took on board five hundred liters of wine, half of which had been
heated under Pasteur's directions. At the end of ten months the
_pasteurized_ wine was mellow and of good color, while the wine which
had not been heated had an astringent, almost bitter, taste. A more
extensive test--seven hundred hectoliters, of which six hundred and
fifty had been pasteurized--was carried out on the frigate la Sibylle
with satisfactory results. Previously wines had been preserved by the
addition of alcohol, which made them both dearer and more detrimental to
health.
In 1865 Pasteur was called upon to exercise his scientific acumen on
behalf of the silk industry. A disease--_pébrine_--had appeared among
silkworms in 1845. In 1849 the effect on the French industry was
disastrous. In the single _arrondissement_ of Alais an annual income of
120,000,000 francs was lost for the subsequent fifteen years. The
mulberry plantations of the Cévennes were abandoned and the whole region
was desolate. Pasteur, at the instigation of the Minister of
Agriculture, undertook an investigation. After four or five years, in
spite of repeated domestic afflictions and the breakdown of his own
health, he arrived at a successful conclusion. _Pébrine_, due to
"corpuscles" readily detected under the microscope, could be recognized
at the moment of the moth's formation. A second disease, _flacherie_,
was due to a micro-organism found in the digestive cavity of the moth.
Measures were taken to select the seed of the healthy moths and to
destroy the others. These investigations revealed the infinitesimally
small as disorganizers of living tissue, and brought Pasteur nearer his
purpose "of arriving," as he had expressed it to Napoleon III in 1863,
"at the knowledge of the causes of putrid and contagious diseases."
Returning in July, 1870, from a visit to Liebig at Munich, Pasteur heard
at Strasburg of the imminence of war. All his dreams of conquest over
disease and death seemed to vanish. He hurried to Paris. His son,
eighteen years of age, set out with the army. Every student of the
Ecole Normale enlisted. Pasteur's laboratory was used to house soldiers.
He himself wished to be enrolled in the National Guard, and had to be
told that a half-paralyzed man could not render military service. He was
obsessed with horror of wanton bloodshed and with indignation at the
insolence of armed injustice. Trained to serve his country only in one
way he tried, but in vain, to resume his researches. He retired to the
old home town of Arbois, and sought to distract his mind from the
contemplation of human baseness. Arbois was entered by the enemy in
January with the usual atrocities of war. Pasteur accompanied by wife
and daughter had gone in search of his son, sick at Pontarlier. The boy
was restored to health and returned to his regiment the following month.
During this crisis Pasteur and his friends felt, as many English
scientists feel in 1917, in reference to ignorance in high places. "We
are paying the penalty," he said, "of fifty years' forgetfulness of
science, and of its conditions of development." Again he speaks, as
Englishmen to-day very well might, of the neglect, disdain even, of the
country for great intellectual men, especially in the realm of exact
science. In the same strain his friend Bertin said that after the war
everything would have to be rebuilt from the top to the bottom, the top
especially. Pasteur recalled the period of 1792 when Lavoisier,
Berthollet, Monge, Fourcroy, Guyton de Morveau, Chaptal, Clouet, and
other scientists had furnished France with gunpowder, steel, cannon,
fortifications, balloons, leather, and other means to repel unjust
invasion.
On the day after Sedan the Quaker surgeon Lister had published
directions for the use of aqueous solutions of carbolic acid to destroy
septic particles in wounds, and of oily solutions "to prevent
putrefactive fermentation from without." He recognized that the earlier
the case comes from the field the greater the prospect of success.
Sédillot (the originator of the term "microbe"), at the head of an
ambulance corps in Alsace, was a pioneer in the rapid transport of
wounded from the field of battle. He knew the horrors of purulent
infection in military hospitals, and regretted that the principles of
Pasteur and Lister were not more fully applied.
After the war was over, Pasteur kept repeating his life-long
exhortation: We must work--"_Travaillez, travaillez toujours!_" He
applied himself to a study of the brewing industry. He did not believe
in spontaneous alterations, but found that every marked change in the
quality of beer coincides with the development of micro-organisms. He
was able to tell the English brewers the defects in their output by a
microscopic examination of their yeast. ("We must make some friends for
our beloved France," he said.) Bottled beer could be pasteurized by
bringing it to a temperature of 50° to 55° C. Whenever beer contains no
ferments it is unalterable. His scrupulous mind was coming ever closer
to the goal of his ambition. This study of the diseases of beer led him
nearer to a knowledge of infections. Many micro-organisms may, _must_,
be detrimental to the health of man and animals.
In 1874 the Government conferred upon Pasteur a life annuity of twelve
thousand francs, an equivalent of his salary as Professor of Chemistry
at the Sorbonne. (He had received appointment in 1867, but had been
compelled by ill-health to relinquish his academic functions.) The grant
was in all respects wise. Huxley remarked that Pasteur's discoveries
alone would suffice to cover the war indemnity of five milliards paid by
France to Germany in 1871. Moreover, all his activities were dictated by
patriotic motives. He felt that science is of no country and that its
conquests belong to mankind, but that the scientist must be a patriot in
the service of his native land.
Pasteur now applied his energies to the study of virulent diseases,
following the principles of his earlier investigations. He opposed those
physicians who believed in the spontaneity of disease, and he wished to
wage a war of extermination against all injurious organisms. As early as
1850 Davaine and Rayer had shown that a rod-like micro-organism was
always present in the blood of animals dying of anthrax, a disease which
was destroying the flocks and herds of France. Dr. Koch, who had served
in the Franco-Prussian War, succeeded in 1876 in obtaining pure cultures
of this bacillus and in defining its relation to the disease. Pasteur
took up the study of anthrax in 1877, verified previous discoveries,
and, as we shall see, sought means for the prevention of this pest. He
discovered (with Joubert and Chamberland) the bacillus of malignant
edema. He applied the principles of bacteriology to the treatment of
puerperal fever, which in 1864 had rendered fatal 310 cases out of 1350
confinements in the Maternité in Paris. Here he had to fight against
conservatism in the medical profession, and he fought strenuously, one
of his disciples remarking that it is characteristic of lofty minds to
put passion into ideas. Swine plague, which in the United States in 1879
destroyed over a million hogs, and chicken cholera, also engaged his
attention.
Cultures of chicken cholera virus kept for some time became less active.
A hen that chanced to be inoculated with the weakened virus developed
the disease, but, after a time, recovered (much as patients after the
old-time smallpox inoculations). It was then inoculated with a fresh
culture supposed sufficient to cause death. It again recovered. The use
of the weakened inoculation had developed its resistance to infection. A
weakened virus recovered its strength when passed through a number of
sparrows, the second being inoculated with virus from the first, the
third from the second, and so on (this species being subject to the
disease). Hens that had not had chicken cholera could be rendered immune
by a series of attenuated inoculations gradually increasing in strength.
In the case of anthrax the virus could be weakened by keeping it at a
certain temperature, while it could be strengthened by passage through a
succession of guinea-pigs. There are of course many instances where
pathogenic bacteria lose virulence in passing from one animal to
another, the human smallpox virus, for example, producing typical cowpox
in an inoculated heifer. These facts help to explain why certain
infections have grown less virulent in the course of history, and why
infections of which civilized man has become tolerant prove fatal when
imparted to the primitive peoples of Australia.
Pasteur's preventive inoculation for anthrax was tested under dramatic
circumstances at Melun in June, 1881. Sixty sheep and a number of cows
were subjected to experiment. None of the sheep that had been given the
preventive treatment died from the crucial inoculation; while all those
succumbed which had not received previous treatment. The test for the
cows was likewise successful. Pasteur thought that in places where sheep
dead of anthrax had been buried, the microbes were brought to the
surface in the castings of earthworms. Hence he issued certain
directions to prevent the transmission of the disease. He also aided
agriculture by discovering a vaccine for swine plague.
When Pasteur at the age of fifteen was in Paris, overcome with
homesickness, he had exclaimed, "If I could only get a whiff of the old
tannery yard, I feel I should be cured." Certainly every time he came in
contact with the industries--silk, wine, beer, wool--his scientific
insight, Antæus-like, seemed to revive. All his life he had preached the
doctrine of interchange of service between theory and practice, science
and the occupations. What he did is more eloquent than words. His theory
of molecular dissymmetry, that the atoms in a molecule may be arranged
in left-hand and right-hand spirals or other tridimensional figures
corresponding to asymmetrical crystals, touches the abstruse question of
the constitution of matter. His preventive treatment breathes new life
into the old dictum _similia similibus curantur_. The view he adopted of
the gradual transformation of species offers a new interpretation of the
speculations of philosophy in reference to being and becoming and the
relation of the real to the concrete. Yet Pasteur felt he could learn
much of value from the simplest shepherd or vine-dresser.
He was complete in the simplicity of his affections, in his compassion
for all suffering, in the warmth of his religious faith, and in his
devotion to his country. He thought France was to regain her place in
the world's esteem through scientific progress. He was therefore
especially gratified in August, 1881, at the thunders of applause which
greeted his appearance at the International Medical Congress in London.
There he was introduced to the Prince of Wales (_fondateur de l'Entente
Cordiale_), "to whom I bowed, saying that I was happy to salute a friend
of France."
Pasteur's investigation of rabies began in this same year. Difficulty
was found in isolating the microbe of the rabic virus, but an
inoculation from the medulla oblongata of a mad dog injected into one of
the brain membranes (dura mater) of another dog invariably brought on
the symptoms of rabies. To obtain attenuation of the virus it was
sufficient to dry the medulla taken from an infected rabbit. The
weakened virus increased in strength when cultivated in a series of
rabbits. Pasteur obtained in inoculations of graded virulence, which
could be administered hypodermically, a means of prophylaxis after
bites. He conjectured that in vaccinal immunity the virus is accompanied
by a substance which makes the nervous tissue unfavorable for the
development of the microbe.
It was not till 1885 that he ventured to use his discovery to prevent
hydrophobia. On July 6 a little boy, Joseph Meister, from a small place
in Alsace was brought by his mother to Paris for treatment. He had been
severely bitten by a mad dog. Pasteur, with great trepidation, but moved
by his usual compassion, undertook the case. The inoculations of the
attenuated virus began at once. The boy suffered little inconvenience,
playing about the laboratory during the ten days the treatment lasted.
Pasteur was racked with fears alternating with hopes, his anxiety
growing more intense as the virulence of the inoculations increased. On
August 20, however, even he was convinced that the treatment was a
complete success. In October a shepherd lad, who, though badly bitten
himself, had saved some other children from the attack of a rabid dog,
was the second one to benefit by the great discovery. Pasteur's exchange
of letters with these boys after they had returned to their homes
reveals the kindliness of his disposition. His sentiment toward children
had regard both to what they were and to what they might become. One
patient, brought to him thirty-seven days after being bitten, he failed
to save. By March 1 Pasteur reported that three hundred and fifty cases
had been treated with only one death.
When subscriptions were opened for the erection and endowment of the
Pasteur Institute, a sum of 2,586,680 francs was received in
contributions from many different parts of the world. Noteworthy among
the contributors were the Emperor of Brazil, the Czar of Russia, the
Sultan of Turkey, and the peasants of Alsace. On November 14, 1888,
President Carnot opened the institution, which was soon to witness the
triumphs of Roux, Yersin, Metchnikoff, and other disciples of Pasteur.
In the address prepared for this occasion the veteran scientist wrote:--
"If I might be allowed, M. le Président, to conclude by a philosophical
remark, inspired by your presence in this home of work, I should say
that two contrary laws seem to be wrestling with each other at the
present time; the one a law of blood and death, ever devising new means
of destruction and forcing nations to be constantly ready for the
battlefield--the other, a law of peace, work, and health, ever
developing new means of delivering man from the scourges which beset
him.
"The one seeks violent conquests, the other the relief of humanity. The
latter places one human life above any victory; while the former would
sacrifice hundreds and thousands of lives to the ambition of one. The
law of which we are the instruments seeks, even in the midst of carnage,
to cure the sanguinary ills of the law of war; the treatment inspired by
our antiseptic methods may preserve thousands of soldiers. Which of
these two laws will ultimately prevail God alone knows. But we may
assert that French science will have tried, by obeying the law of
humanity, to extend the frontiers of life."
REFERENCES
W. W. Ford, _The Life and Work of Robert Koch_, Bulletin of the Johns
Hopkins Hospital, Dec. 1911, vol. 22.
C. A. Herter, _The Influence of Pasteur on Medical Science_, Bulletin
of the Johns Hopkins Hospital, Dec. 1903, vol. 14.
E. O. Jordan, _General Bacteriology_ (fourth edition, 1915).
Charles C. W. Judd, _The Life and Work of Lister_, Bulletin of the
Johns Hopkins Hospital, Oct. 1910, vol. 21.
Stephen Paget, _Pasteur and After Pasteur_.
W. T. Sedgwick, _Principles of Sanitary Science_.
René Vallery-Radot, _Life of Pasteur_.
CHAPTER XVII
SCIENCE AND INVENTION--LANGLEY'S AEROPLANE
In his laudation of the nineteenth century Alfred Russel Wallace
ventured to enumerate the chief inventions of that period: (1) Railways;
(2) steam navigation; (3) electric telegraphs; (4) the telephone; (5)
friction matches; (6) gas-lighting; (7) electric-lighting; (8)
photography; (9) the phonograph; (10) electric transmission of power;
(11) Röntgen rays; (12) spectrum analysis; (13) anæsthetics; (14)
antiseptic surgery. All preceding centuries--less glorious than the
nineteenth--can claim but seven or eight capital inventions: (1)
Alphabetic writing; (2) Arabic numerals; (3) the mariner's compass; (4)
printing; (5) the telescope; (6) the barometer and thermometer; (7) the
steam engine. Similarly, to the nineteenth century thirteen important
theoretical discoveries are ascribed, to the eighteenth only two, and to
the seventeenth five.
Of course the very purpose of these lists--namely, to compare the
achievements of one century with those of other centuries--inclines us
to view each invention as an isolated phenomenon, disregarding its
antecedents and its relation to contemporary inventions. Studied in its
development, steam navigation is but an application of one kind of steam
engine, and, moreover, must be viewed as a phase in the evolution of
navigation since the earliest times. Like considerations would
apply to railways, antiseptic surgery, or friction matches. The
nineteenth-century inventor of the friction match was certainly no more
ingenious (considering the means that chemistry had put at his disposal)
than many of the savages who contributed by their intelligence to
methods of producing, maintaining, and using fire. In fact, as we
approach the consideration of prehistoric times it becomes difficult to
distinguish inventions from the slow results of development--in
metallurgy, tool-making, building, pottery, war-gear, weaving, cooking,
the domestication of animals, the selection and cultivation of plants.
Moreover, it is scarcely in the category of invention that the
acquisition of alphabetic writing or the use of Arabic numerals properly
belongs.
These and other objections, such as the omission of explosives,
firearms, paper, will readily occur to the reader. Nevertheless, these
lists, placed side by side with the record of theoretic discoveries,
encourage the belief that, more and more, sound theory is productive of
useful inventions, and that henceforth it must fall to scientific
endeavor rather than to lucky accident to strengthen man's control over
Nature. Even as late as the middle of the nineteenth century accident
and not science was regarded as the fountain-head of invention, and the
view that a knowledge of the causes and secret motions of things would
lead to "the enlarging of the bounds of human empire to the effecting of
all things possible" was scouted as the idle dream of a doctrinaire.
In the year 1896 three important advances were made in man's mastery of
his environment. These are associated with the names of Marconi,
Becquerel, and Langley. It was in this year that the last-named,
long known to the scientific world for his discoveries in solar
physics, demonstrated in the judgment of competent witnesses the
practicability of mechanical flight. This was the result of nine years'
experimentation. It was followed by several more years of fruitful
investigation, leading to that ultimate triumph which it was given to
Samuel Pierpont Langley to see only with the eye of faith.
The English language has need of a new word ("plane") to signify the
floating of a bird upon the wing with slight, or no, apparent motion of
the wings (_planer_, _schweben_). _To hover_ has other connotations,
while _to soar_ is properly to fly upward, and not to hang poised upon
the air. The miracle of a bird's flight, that steady and almost
effortless motion, had interested Langley intensely--as had also the
sun's radiation--from the years of his childhood. The phenomenon (the
way of an eagle in the air) has always, indeed, fascinated the human
imagination and at the same time baffled the comprehension. The skater
on smooth ice, the ship riding at sea, or even the fish floating in
water, offers only an incomplete analogy; for the fish has approximately
the same weight as the water it displaces, while a turkey buzzard of two
or three pounds' weight will circle by the half-hour on motionless wing
upheld only by the thin medium of the air.
In 1887, prior to his removal to Washington as Secretary of the
Smithsonian Institution, Langley began his experiments in aerodynamics
at the old observatory in Allegheny--now a part of the city of
Pittsburgh. His chief apparatus was a whirling table, sixty feet in
diameter, and with an outside speed of seventy miles an hour. This was
at first driven by a gas engine,--ironically named "Automatic,"--for
which a steam engine was substituted in the following year. By means of
the whirling table and a resistance-gauge (dynamometer chronograph)
Langley studied the effect of the air on planes of varying lengths and
breadths, set at varying angles, and borne horizontally at different
velocities. At times he substituted stuffed birds for the metal planes,
on the action of which under air pressure his scientific deductions were
based. In 1891 he published the results of his experiments. These
proved--in opposition to the teaching of some very distinguished
scientists--that the force required to sustain inclined planes in
horizontal locomotion through the air diminishes with increased velocity
(at least within the limits of the experiment). Here a marked contrast
is shown between aerial locomotion on the one hand, and land and water
locomotion on the other; "whereas in land or marine transport increased
speed is maintained only by a disproportionate expenditure of power,
within the limits of experiment in such _aerial horizontal transport,
the higher speeds are more economical of power than the lower ones_."
Again, the experiments demonstrated that the force necessary to maintain
at high velocity an apparatus consisting of planes and motors could be
produced by means already available. It was found, for example, that one
horse-power rightly applied is sufficient to maintain a plane of two
hundred pounds in horizontal flight at a rate of about forty-five miles
an hour. Langley had in fact furnished experimental proof that the
aerial locomotion of bodies many times heavier than air was possible. He
reserved for further experimentation the question of aerodromics, the
form, ascent, maintenance in horizontal position, and descent of an
aerodrome (ἀεροδρόμος, traversing the air), as he called the prospective
flying machine. He believed, however, that the time had come for
seriously considering these things, and intelligent physicists, who
before the publication of Langley's experiments had regarded all plans
of aerial navigation as utopian, soon came to share his belief.
According to Octave Chanute there was in Europe in 1889 utter
disagreement and confusion in reference to fundamental questions of
aerodynamics. He thought Langley had given firm ground to stand upon
concerning air resistances and reactions, and that the beginning of the
solution of the problem of aerial navigation would date from the
American scientist's experiments in aerodynamics.
Very early in his investigations Langley thought he received through
watching the anemometer a clue to the mystery of flight. Observations,
begun at Pittsburgh in 1887 and continued at Washington in 1893,
convinced him that the course of the wind is "a series of complex and
little-known phenomena," and that a wind to which we may assign a mean
velocity of twenty or thirty miles an hour, even disregarding the
question of strata and currents, is far from being a mere mass movement,
and consists of pulsations varying both in rate and direction from
second to second. If this complexity is revealed by the stationary
anemometer--which may register a momentary calm in the midst of a
gale--how great a diversity of pressure must exist in a large extent of
atmosphere. This _internal work of the wind_ will lift the soaring bird
at times to higher levels, from which without special movement of the
wings it may descend in the very face of the wind's general course.
From the beginning, however, of his experiments Langley had sought to
devise a successful flying machine. In 1887 and the following years he
constructed about forty rubber-driven models, all of which were
submitted to trial and modification. From these tests he felt that he
learned much about the conditions of flight in free air which could not
be learned from the more definitely controlled tests with simple planes
on the whirling table. His essential object was, of course, to reduce
the principles of equilibrium to practice. Besides different forms and
sizes he tried various materials of construction, and ultimately various
means of propulsion. Before he could test his larger steam-driven
models, made for the most part of steel and weighing about one thousand
times as much as the air displaced, Langley spent many months contriving
and constructing suitable launching apparatus. The solution of the
problem of safe descent after flight he in a sense postponed, conducting
his experiments from a house-boat on the Potomac, where the model might
come down without serious damage.
[Illustration: THE FIRST SUCCESSFUL HEAVIER-THAN-AIR FLYING MACHINE
A photograph taken at the moment of launching Langley's aerodrome May 6,
1896]
It was on May 6, 1896 (the anniversary of which date is now celebrated
as Langley Day), that the success was achieved which all who witnessed
it considered decisive of the future of mechanical flight. The whole
apparatus--steel frame, miniature steam engine, smoke stack,
condensed-air chamber, gasoline tank, wooden propellers, wings--weighed
about twenty-four pounds. There was developed a steam pressure of about
115 pounds, and the actual power was nearly one horse-power. At a given
signal the aeroplane was released from the overhead launching apparatus
on the upper deck of the house-boat. It rose steadily to an ultimate
height of from seventy to a hundred feet. It circled (owing to the guys
of one wing being loose) to the right, completing two circles and
beginning a third as it advanced; so that the whole course had the form
of a spiral. At the end of one minute and twenty seconds the propellers
began to slow down owing to the exhaustion of fuel. The aeroplane
descended slowly and gracefully, appearing to settle on the water. It
seemed to Alexander Graham Bell that no one could witness this
interesting spectacle, of a flying machine in perfect equilibrium,
without being convinced that the possibility of aerial flight by
mechanical means had been demonstrated. On the very day of the test he
wrote to the Académie des Sciences that there had never before been
constructed, so far as he knew, a heavier-than-air flying machine, or
aerodrome, which could by its own power maintain itself in the air for
more than a few seconds.
Langley felt that he had now completed the work in this field which
properly belonged to him as a scientist--"the demonstration of the
practicability of mechanical flight"--and that the public might look to
others for its development and commercial exploitation. Like Franklin
and Davy he declined to take out patents, or in any way to make money
from scientific discovery; and like Henry, the first Secretary of
the Smithsonian Institution (to whom the early development of
electro-magnetic machines was due), he preferred to be known as a
scientist rather than as an inventor.
Nevertheless, Langley's desire to construct a large, man-carrying
aeroplane ultimately became irresistible. Just before the outbreak of
the Spanish War in 1898 he felt that such a machine might be of service
to his country in the event of hostilities that seemed to him imminent.
The attention of President McKinley was called to the matter, and a
joint commission of Army and Navy officers was appointed to make
investigation of the results of Professor Langley's experiments in
aerial navigation. A favorable report having been made by that body, the
Board of Ordnance and Fortification recommended a grant of fifty
thousand dollars to defray the expenses of further research. Langley was
requested to undertake the construction of a machine which might lead to
the development of an engine of war, and in December, 1898, he formally
agreed to go on with the work.
He hoped at first to obtain from manufacturers a gasoline engine
sufficiently light and sufficiently powerful for a man-carrying machine.
After several disappointments, the automobile industry being then in its
infancy, he succeeded in constructing a five-cylinder gasoline motor of
fifty-two horse-power and weighing only about a hundred and twenty
pounds. He also constructed new launching apparatus. After tests with
superposed sustaining surfaces, he adhered to the "single-tier plan."
There is interesting evidence that in 1900 Langley renewed his study of
the flight of soaring birds, the area of their extended wing surface in
relation to weight, and the vertical distance between the center of
pressure and the center of gravity in gulls and different species of
buzzards. He noted among other things that the tilting of a wing was
sufficient to bring about a complete change of direction.
By the summer of 1903 two new machines were ready for field trials,
which were undertaken from a large house-boat, especially constructed
for the purpose and then moored in the mid-stream of the Potomac about
forty miles below Washington. The larger of these two machines weighed
seven hundred and five pounds and was designed to carry an engineer to
control the motor and direct the flight. The motive power was supplied
by the light and powerful gasoline engine already referred to. The
smaller aeroplane was a quarter-size model of the larger one. It weighed
fifty-eight pounds, had an engine of between two and a half and three
horse-power, and a sustaining surface of sixty-six square feet.
This smaller machine was tested August 8, 1903, the same launching
apparatus being employed as with the steam-driven models of 1896. In
spite of the fact that one of the mechanics failed to withdraw a certain
pin at the moment of launching, and that some breakage of the apparatus
consequently occurred, the aeroplane made a good start, and fulfilled
the main purpose of the test by maintaining a perfect equilibrium. After
moving about three hundred and fifty feet in a straight course it
wheeled a quarter-circle to the right, at the same time descending
slightly, the engine slowing down. Then it began to rise, moving
straight ahead again for three or four hundred feet, the propellers
picking up their former rate. Once more the engine slackened, but,
before the aeroplane reached the water, seemed to regain its normal
speed. For a third time the engine slowed down, and, before it
recovered, the aeroplane had touched the water. It had traversed a
distance of one thousand feet in twenty-seven seconds. One of the
workmen confessed that he had poured into the tank too much gasoline.
This had caused an overflow into the intake pipe, which in turn
interfered with the action of a valve.
The larger aeroplane with the engineer Manly on board was first tested
on October 7 of the same year, but the front guy post caught in the
launching car and the machine plunged into the water a few feet from the
house-boat. In spite of this discouraging mishap the engineers and
others present felt confidence in the aeroplane's power to fly. What
would to-day be regarded by an aeronaut as a slight setback seemed at
that moment like a tragic failure. The fifty thousand dollars had been
exhausted nearly two years previously; Professor Langley had made as
full use as seemed to him advisable of the resources put at his disposal
by the Smithsonian Institution; the young men of the press, for whom the
supposed aberration of a great scientist furnished excellent copy, were
virulent in their criticisms. Manly made one more heroic attempt under
very unfavorable conditions at the close of a winter's day (December 8,
1903). Again difficulty occurred with the launching gear, the rear wings
and rudder being wrecked before the aeroplane was clear of the ways.
The experiments were now definitely abandoned, and the inventor was
overwhelmed by the sense of failure, and still more by the skepticism
with which the public had regarded his endeavors.
In 1905 an account of Langley's aeroplane appeared in the Bulletin of
the Italian Aeronautical Society. Two years later this same publication
in an article on a new Blériot aeroplane said: "The Blériot IV in the
form of a bird ... does not appear to give good results, perhaps on
account of the lack of stability, and Blériot, instead of trying some
new modification which might remedy such a grave fault, laid it aside
and at once began the construction of a new type, No. V, adopting purely
and simply the arrangement of the American, Langley, which offers a good
stability." In the summer of 1907 Blériot obtained striking results with
this machine, the launching problem having been solved in the previous
year--the year of Langley's death--by the use of wheels which permitted
the aeroplane to get under way by running along the ground under its own
driving power. The early flights with No. V were made at a few feet from
the ground, and the clever French aviator could affect the direction of
the machine by slightly shifting his position, and even had skill to
bring it down by simply leaning forward. By the use of the steering
apparatus he circled to the right or to the left with the grace of a
bird on the wing. When, on July 25, 1909, Blériot crossed the English
Channel in his monoplane, all the world knew that man's conquest of the
air was a _fait accompli_.
About three years after Langley's death the Board of Regents of the
Smithsonian Institution established the Langley Medal for investigations
in aerodromics in its application to aviation. The first award went
(1909) to Wilbur and Orville Wright, the second (1913) to Mr. Glenn H.
Curtiss and M. Gustave Eiffel. On the occasion of the presentation of
the medals of the second award--May 6, 1913--the Langley Memorial
Tablet, erected in the main vestibule of the Smithsonian building, was
unveiled by the scientist's old friend, Dr. John A. Brashear. In the
words of the present Secretary of the Institution, the tablet represents
Mr. Langley seated on a terrace where he has a clear view of the
heavens, and, in a meditative mood, is observing the flight of birds,
while in his mind he sees his aerodrome soaring above them.
The lettering of the tablet is as follows:--
SAMUEL PIERPONT LANGLEY
1834-1906
SECRETARY OF THE SMITHSONIAN INSTITUTION
1887-1906
DISCOVERED THE RELATIONS OF SPEED
AND ANGLE OF INCLINATION TO THE
LIFTING POWER OF SURFACES WHEN
MOVING IN AIR
"I have brought to a close the portion of the work which seemed to
be especially mine, the demonstration of the practicability of
mechanical flight."
"The great universal highway overhead is now soon to be
opened."--Langley, 1897.
A still more fitting tribute to the memory of the great inventor came
two years later from a successful aviator. In the spring of 1914 Mr.
Glenn H. Curtiss was invited to send apparatus to Washington for the
Langley Day Celebration. He expressed the desire to put the Langley
aeroplane itself in the air. The machine was taken to the Curtiss
Aviation Field at Keuka Lake, New York. Langley's method of launching
had been proved practical, but Curtiss finally decided to start from the
water, and accordingly fitted the aeroplane with hydroaeroplane floats.
In spite of the great increase in weight involved by this addition, the
Langley aeroplane, under its own power plant, skimmed over the wavelets,
rose from the lake, and soared gracefully in the air, maintaining its
equilibrium, on May 28, 1914, over eight years after the death of its
designer. When furnished with an eighty horse-power motor, more suited
to its increased weight, the aerodrome planed easily over the water in
more prolonged flight. In the periodical publications of June, 1914, may
be read the eloquent announcement: "Langley's Folly Flies."
REFERENCES
Alexander Graham Bell, Experiments in Mechanical Flight, _Nature_, May
28, 1896.
Alexander Graham Bell, The Pioneer Aerial Flight, _Scientific
American_, Supplement, Feb. 26, 1910.
S. P. Langley, _Experiments in Aerodynamics_.
S. P. Langley, The "Flying Machine," _McClure's_, June, 1897
(illustrated).
_Langley Memoir on Mechanical Flight, Smithsonian Contributions to
Knowledge_, vol. 27, no. 3 (illustrated).
_Scientific American_, Jan. 13, 1912, A Memorial Honor to a Pioneer
Inventor.
_The Smithsonian Institution 1846-1896. The History of its First
Half-Century_, edited by G. B. Goode.
A. F. Zahm, _The First Man-carrying Aeroplane capable of Sustained Free
Flight_, Annual Report of the Smithsonian Institution, 1914
(illustrated).
CHAPTER XVIII
SCIENTIFIC HYPOTHESIS--RADIOACTIVE SUBSTANCES
The untrained mind, reliant on so-called facts and distrustful of mere
theory, inclines to think of truth as fixed rather than progressive,
static rather than dynamic. It longs for certainty and repose, and has
little patience for any authority that does not claim absolute
infallibility. Many a man of the world is bewildered to find Newton's
disciples building upon or refuting the teachings of the master, or to
learn that Darwin's doctrine is itself subject to the universal law of
change and development. Though in ethics and religion the older order
changes yielding place to new, and the dispensation of an eye for an eye
and a tooth for a tooth finds its fulfilment and culmination in a
dispensation of forbearance and non-resistance of evil, still many look
upon the overthrow of any scientific theory not as a sign of vitality
and advance, but as a symptom of the early dissolution or at least of
the bankruptcy of science. It is not surprising, therefore, that the
public regard the scientific hypothesis with a kind of contempt; for a
hypothesis (ὑπόθεσις, foundation, supposition) is necessarily ephemeral.
When disproved, it is shown to have been a false supposition; when
proved, it is no longer hypothetic.
Yet a page from the history of science should indicate that hypotheses
play a rôle in experimental science and lead to results that no devotee
of facts and scorner of mere theory can well ignore.
In 1895 Sir William Ramsay, who in the previous year had discovered an
inert gas, argon, in the atmosphere, identified a second inert gas
(obtained from minerals containing uranium and thorium) as helium
(ἥλιος, sun), an element previously revealed by spectrum analysis as a
constituent of the sun. In the same year Röntgen, while experimenting
with the rays that stream from the cathode in a vacuum tube, discovered
new rays (which he called X-rays) possessed of wonderful photographic
power. At the beginning of 1896 Henri Becquerel, experimenting on the
supposition, or hypothesis, that the emission of rays was associated
with phosphorescence, tested the photographic effects of a number of
phosphorescent substances. He exposed, among other compounds, crystals
of the double sulphate of uranium and potassium to sunlight and then
placed upon the crystals a photographic plate wrapped in two thicknesses
of heavy black paper. The outline of the phosphorescent substance was
developed on the plate. An image of a coin was obtained by placing it
between uranic salts and a photographic plate. Two or three days after
reporting this result Becquerel chanced (the sunlight at the time
seeming to him too intermittent for experimentation) to put away in the
same drawer, and in juxtaposition, a photographic plate and these
phosphorescent salts. To his surprise he obtained a clear image when the
plate was developed. He now assumed the existence of invisible rays
similar to X-rays. They proved capable of passing through sheets of
aluminum and of copper, and of discharging electrified bodies. Days
elapsed without any apparent diminution of the radiation. On the
supposition that the rays might resemble light he tried to refract,
reflect, and polarize them; but this hypothesis was by the experiments
of Rutherford, and of Becquerel himself, ultimately overthrown. In the
mean time the French scientist obtained radiations from metallic uranium
and from uranous salts. These, in contrast with the uranic salts, are
non-phosphorescent. Becquerel's original hypothesis was thus overthrown.
Radiation is a property inherent in uranium and independent both of
light and of phosphorescence.
On April 13 and April 23 (1898) respectively Mme. Sklodowska Curie and
G. C. Schmidt published the results of their studies of the radiations
of the salts of thorium. Each of these studies was based on the work of
Becquerel. Mme. Curie examined at the same time the salts of uranium and
a number of uranium ores. Among the latter she made use of the composite
mineral pitchblende from the mines of Joachimsthal and elsewhere, and
found that the radiations from the natural ores are more active than
those from pure uranium. This discovery naturally led to further
investigation, on the assumption that pitchblende contains more than one
radioactive substance. Polonium, named by Mme. Curie in honor of her
native country, was the third radioactive element to be discovered. In
the chemical analysis of pitchblende made by Mme. Curie (assisted by M.
Curie) polonium was found associated with bismuth. Radium, also
discovered in this analysis of 1898, was associated with barium. Mme.
Curie succeeded in obtaining the pure chloride of radium and in
determining the atomic weight of the new element. There is (according to
Soddy) about one part of radium in five million parts of the best
pitchblende, but the new element is about one million times more
radioactive than uranium. It was calculated by M. Curie that the energy
of one gram of radium would suffice to lift a weight of five hundred
tons to a height of one mile. After discussing the bearing of the
discovery of radioactivity on the threatened exhaustion of the coal
supply Soddy writes enthusiastically: "But the recognition of the
boundless and inexhaustible energy of Nature (and the intellectual
gratification it affords) brightens the whole outlook of the twentieth
century." The element yields spontaneously radium emanation without any
apparent diminution of its own mass. In 1899 Debierne discovered, also
in the highly complex pitchblende, actinium, which has proved
considerably less radioactive than radium. During these investigations
M. and Mme. Curie, M. Becquerel, and those associated with them were
influenced by the hypothesis that radioactivity is an _atomic property_
of radioactive substances. This hypothesis came to definite expression
in 1899 and again in 1902 through Mme. Curie.
In the latter year the physicist E. Rutherford and the chemist F. Soddy,
while investigating the radioactivity of thorium in the laboratories of
McGill University, Montreal, were forced to recognize that thorium
continuously gives rise to new kinds of radioactive matter differing
from itself in chemical properties, in stability, and in radiant energy.
They concurred in the view held by all the most prominent workers in
this subject, namely, that radioactivity is an atomic phenomenon. It is
not molecular decomposition. They declared that the radioactive
substances must be undergoing a spontaneous transformation. The daring
nature of this hypothesis and its likelihood to revolutionize physical
science is brought home to one by recalling that three decades
previously an eminent physicist had said that "though in the course of
ages catastrophes have occurred and may yet occur in the heavens, though
ancient systems may be dissolved and new systems evolved out of their
ruins, the molecules [atoms] out of which these systems are built--the
foundation stones of the material universe--remain unbroken and unworn."
In 1903 Rutherford and Soddy stated definitely their hypothesis,
generally known as the "Transformation Theory," that the atoms of
radioactive substances suffer spontaneous disintegration, a process
unaffected by great changes of temperature (or by physical or chemical
changes of any kind at the disposal of the experimenter) and giving rise
to new radioactive substances differing in chemical (and physical)
properties from the parent elements. The radiations consist of α
particles (atoms of helium minus two negative electrons), β particles,
or electrons (charges of negative electricity), and γ rays, of the
nature of Röntgen rays and light but of very much shorter wave length
and of very great penetrating power. It is by the energy inherent in the
atom of the radioactive substance that the radiations are ejected,
sometimes, in the case of the γ rays, with velocity sufficient to
penetrate two feet of lead. It is through these radiations that
spontaneous transformation takes place. After ten years of further
investigation Rutherford stated that this hypothesis affords a
satisfactory explanation of all radioactive phenomena, and gives unity
to what without it would seem disconnected facts. Besides accounting for
old experimental results it suggests new lines of work and even enables
one to predict the outcome of further investigation. It does not really
contradict, as some thought might be the case, the principle of the
conservation of energy. The atom, to be sure, can no longer be
considered the smallest unit of matter, as the mass of a β particle is
approximately one seventeen-hundredths that of an atom of hydrogen.
Still the new hypothesis is a modification and not a contradiction of
the atomic theory.
The assumption that the series of radioactive substances is due, not to
such molecular changes as chemistry had made familiar, but to a
breakdown of the atom seemed to Rutherford in 1913 at least justified by
the results of the investigators whose procedure had been dictated by
that hypothesis. He set forth in tables these results (since somewhat
modified), indicating after the name of each radioactive substance the
nature of the radiation through the emission of which the element is
transformed into the next-succeeding member of its series.
_List of Radioactive Substances_
URANIUM α particles
Uranium X β + γ
Uranium Y β
IONIUM α
RADIUM α + slow β
Emanation α
Radium A α
Radium B β + γ
Radium C { C{1} α + β + γ
{ C{2} β
RADIUM D }
RADIO-LEAD } slow β
Radium E β + γ
Radium F }
Polonium } α
THORIUM α
MESOTHORIUM 1 no rays
Mesothorium 2 β + γ
RADIOTHORIUM α
Thorium X α + β
Emanation α
Thorium A α
Thorium B slow β
Thorium C { C{1} α
{ C{2} α
Thorium D β + γ
ACTINIUM no rays
Radio-actinium α + β
Actinium X α
Emanation α
Actinium A α
Actinium B slow β
Actinium C α
Actinium D α + γ
Even a glance at this long list of new elements reveals certain
analogies between one series of transformations and another. Each series
contains an emanation, or gas, which through the loss of α particles is
transformed into the next following member of the series. Continuing the
comparison in either direction, up or down the lists, one could readily
detect other analogies.
There is some ground for thinking that lead is the end product of the
Uranium series. To reverse the process of the transformation and produce
radium from the base metal lead would be an achievement greater than the
vaunted transmutations of the alchemists. Although that seems beyond the
reach of possibility, the idea has stirred the imagination of more than
one scientist. "The philosopher's stone," writes Soddy, "was accredited
the power not only of transmuting the metals, but of acting _as the
elixir of life_. Now, whatever the origin of this apparently meaningless
jumble of ideas may have been, it is really a perfect and but very
slightly allegorical expression of the actual present views we hold
to-day." Again, it is conjectured that bismuth is the end-product of the
thorium series. The presence of the results of atomic disintegration
(like lead and helium) has proved of interest to geology and other
sciences as affording a clue to the age of the rocks in which they are
found deposited.
Before Rutherford, Mme. Curie, and others especially interested in
radioactive substances, assumed that atoms are far different from the
massy, hard, impenetrable particles that Newton took for granted, Sir J.
J. Thomson and his school were studying the constitution of the atom
from another standpoint but with somewhat similar results. This great
physicist had proved that cathode rays are composed not of negatively
charged molecules, as had been supposed, but of much smaller particles
or corpuscles. Wherever, as in the vacuum tube, these electrons appear,
the presence of positively charged particles can also be demonstrated.
It is manifest that the atom, instead of being the ultimate unit of
matter, is a system of positively and negatively charged particles.
Rutherford in the main concurred in this view, though differing from Sir
J. J. Thomson as to the arrangement of corpuscles within the atom. Let
it suffice here to state that Rutherford assumes that the greater mass
of the atom consists of negatively charged particles rotating about a
positive nucleus. The surrounding electrons render the atom electrically
neutral.
This corpuscular theory of matter may throw light on the laws of
chemical combination. The so-called chemical affinity between two atoms
of such and such valencies, which Davy and others since his time had
regarded as essentially an electrical phenomenon, seems now to admit of
more definite interpretation. Each atom is negatively or positively
charged according to the addition or subtraction of electrons. Chemical
composition takes place between atoms the charges of which are of
opposite sign, and valency depends on the number of unit charges of
electricity. Moreover, the electrical theory of matter lends support to
the hypothesis that there is a fundamental unitary element underlying
all the so-called elements. The fact that elements fall into groups and
that their chemical properties vary with their atomic weights long ago
suggested this assumption of a primitive matter, _protyl_, from which
all other substances were derived. In the light of the corpuscular
theory as well as of the transformation theory it seems possible that
the helium atom and the negative corpuscle will offer a clue to the
genesis of the elements.
What is to be learned from this rapid sketch, of the discovery of the
radioactive substances, concerning the nature and value of scientific
hypothesis? For one thing, the scientific hypothesis is necessary to the
experimenter. The mind runs ahead of and guides the experiment. Again,
the hypothesis suggests new lines of research, enables one in some cases
to anticipate the outcome of experiment, and may be abundantly justified
by results. "It is safe to say," writes Rutherford, "that the rapidity
of growth of accurate knowledge of radioactive phenomena has been
largely due to the influence of the disintegration theory." The valid
hypothesis serves to explain facts, leads to discovery, and does not
conflict with known facts or with verified generalizations, though, as
we have seen, it may modify other hypotheses. Those who support a
hypothesis should bring it to the test of rigid verification, avoiding
skepticism, shunning credulity. Even a false assumption, as we have
seen, may prove valuable when carefully put to the proof.
The layman's distrust of the unverified hypothesis is in the main
wholesome. It is a duty not to believe it, not to disbelieve it, but to
weigh judicially the evidence for and against. The fact that assumption
plays a large part in our mental attitude toward practical affairs
should make us wary of contesting the legitimacy of scientific
hypotheses.
No one would deny the right of forming a provisional assumption to the
intelligence officer interpreting a cipher, or to the detective
unravelling the mystery of a crime. The first assumes that the message
is in a certain language, and, perhaps, that each symbol employed is the
equivalent of a letter, his assumption is put to the proof of getting a
reasonable and consistent meaning from the cipher. The detective assumes
a motive for the crime, or the employment of certain means of escape;
even if his assumption does not clear up the mystery, it may have value
as leading to a new and more adequate assumption.
Henri Poincaré has pointed out that one of the most dangerous forms of
hypothesis is the unconscious hypothesis. It is difficult to prove or
disprove because it does not come to clear statement. The alleged
devotee of facts and of things as they are, in opposing the assumptions
of an up-to-date science, is often, unknown to himself, standing on a
platform of outworn theory, or of mere vulgar assumption. For example,
when Napoleon was trying to destroy the commercial wealth of England at
the beginning of the nineteenth century, he unconsciously based his
procedure on an antiquated doctrine of political economy. For him the
teachings of Adam Smith and Turgot were idle sophistries. "I seek," he
said to his Minister of Finance, "the good that is practical, not the
ideal best: the world is very old, we must profit by its experience; it
teaches that old practices are worth more than new theories: you are not
the only one who knows trade secrets." We are not here especially
concerned with the question of whether Napoleon was or was not pursuing
the best means of breaking down English credit. He did try to prevent
the English from exchanging exports for European gold, while permitting
imports in the hope of depleting England of gold. But in pursuing this
policy he thought he was proceeding on the ground of immemorial
practice, while he was merely pitting the seventeenth-century doctrine
of Locke against the doctrine of Adam Smith which had superseded it.
According to one scientific hypothesis, "Species originated by means of
natural selection, or, through the preservation of favored races in the
struggle for life." This assumption was rightly subjected to close
scrutiny in 1859 and the years following. The ephemeral nature of the
vast majority of hypotheses and the danger to progress of accepting an
unverified assumption justify the demand for demonstrative evidence. The
testimony having been examined, it is our privilege to state and to
support the opposing hypothesis. It was thus that the hypothesis that
the planets move in circular orbits, recommended by its simplicity and
æsthetic quality, was forced to give way to the hypothesis of elliptical
orbits. Newton's hypothesis that light is due to particles emitted by
all luminous bodies yielded, at least for the time, to the theory of
light vibrations in an ether pervading all space. The path of scientific
progress is strewn with the ruins of overthrown hypotheses. Many of the
defeated assumptions have been merely implicit errors of the man in the
street, and they are overthrown not by facts alone, but by new
hypotheses verified by facts and leading to fresh discoveries.
According to John Stuart Mill, "It appears ... to be a condition of a
genuinely scientific hypothesis, that it be not destined always to
remain an hypothesis, but be of such a nature as to be either proved or
disproved by that comparison with observed facts which is termed
Verification." This statement is of value in confirming the general
distrust of _mere_ hypothesis, and in distinguishing between the
unverified and unverifiable presupposition and the legitimate assumption
which through verification may become established doctrine.
REFERENCES
J. Cox, _Beyond the Atom_, 1913 (Cambridge Manuals of Science and
Literature).
R. K. Duncan, _The New Knowledge_, 1905.
H. Poincaré, _Science and Hypothesis_.
E. Rutherford, _Radioactive Substances and their Radiations_.
F. Soddy, _The Interpretation of Radium_.
F. Soddy, _Matter and Energy_ (Home University Library).
Sir William A. Tilden, _Progress of Scientific Chemistry in our Own
Time_, 1913.
CHAPTER XIX
THE SCIENTIFIC IMAGINATION
Psychology, or the science of mental life as revealed in behavior, has
been greatly indebted to physiologists and to students of medicine in
general. Any attempt to catalogue the names of those who have approached
the study of the mind from the direction of the natural sciences is
liable to prove unsatisfactory, and a brief list is sure to entail many
important omissions. The mention of Locke, Cheselden, Hartley, Cabanis,
Young, Weber, Gall, Müller, Du Bois-Reymond, Bell, Magendie, Helmholtz,
Darwin, Lotze, Ferrier, Goltz, Munk, Mosso, Maudsley, Carpenter, Galton,
Hering, Clouston, James, Janet, Kraepelin, Flechsig, and Wundt will,
however, serve to remind us of the richness of the contribution of the
natural sciences to the so-called mental science. Indeed, physiology
would be incomplete unless it took account of the functions of the sense
organs, of the sensory and motor nerves, of the brain with its
association areas, as well as the expression of the emotions, and the
changes of function accompanying the development of the nervous system,
from the formation of the embryo till physical dissolution, and from
species of the simplest to those of the most complex organization.
At the beginning of the nineteenth century the French physician Cabanis
was disposed to identify human personality with mere nervous
organization reacting to physical impressions, and to look upon the
brain as the organ for the production of mind. He soon, however,
withdrew from this extreme position and expressed his conviction of the
existence of an immortal spirit apart from the body. One might say that
the brain is the instrument through which the mind manifests itself
rather than the organ by which mind is excreted. Even so, it must be
agreed that the relation between the psychic agent and the physical
instrument is so close that physiology must take heed of mental
phenomena and that psychology must not ignore the physical concomitants
of mental processes. Hence arises a new branch of natural science,
physiological psychology, or, as Fechner (1860), the disciple of Weber,
called it, psycho-physics.
Through this alliance between the study of the mind and the study of
bodily functions the intelligence of the lower animals and its survival
value, the mental growth of the child, mental deterioration in age and
disease, and the psychological endowments of special classes or of
individuals, became subjects for investigation. Now human psychology is
recognized as contributing to various branches of anthropology, or the
general study of man.
Wilhelm Wundt, who, as already implied, had approached the study of the
mind from the side of the natural sciences, established in 1875 at the
University of Leipzig the first psycho-physical institute for the
experimental study of mental phenomena. His express purpose was to
analyze the content of consciousness into its elements, to examine these
elements in their qualitative and quantitative differences, and to
determine with precision the conditions of their existence and
succession. Thus science after contemplating a wide range of outer
phenomena--plants, animals, earth's crust, heavenly bodies, molecules
and atoms--turns its attention with keen scrutiny inward on the thinking
mind, the subjective process by which man becomes cognizant of all
objective things.
The need of expert study of the human mind as the instrument of
scientific discovery might have been inferred from the fact that the
physicist Tyndall read before the British Association in 1870 a paper on
the Scientific Use of the Imagination, in which he spoke of the
imagination as the architect of physical theory, cited Newton, Dalton,
Davy, and Faraday as affording examples of the just use of this creative
power of the mind, and quoted a distinguished chemist as identifying the
mental process of scientific discovery with that of artistic production.
Tyndall even chased the psychologists in their own field and stated that
it was only by the exercise of the imagination that we could ascribe the
possession of mental powers to our fellow creatures. "You believe that
in society you are surrounded by reasonable beings like yourself....
What is your warrant for this conviction? Simply and solely this: your
fellow-creatures behave as if they were reasonable."
On the traces of this brilliant incursion of the natural philosopher
into the realm of mental science, later psychologists must follow but
haltingly. Just as in the history of physics a long series of studies
intervened between Bacon's hypothesis that heat is a kind of motion
(1620) and Tyndall's own work, _Heat as a Mode of Motion_ (1863), so
must many psychological investigations be made before an adequate
psychology of scientific discovery can be formulated. It may ultimately
prove that the passages in which Tyndall and other scientists speak of
scientific _imagination_ would read as well if for this term, intuition,
inspiration, unconscious cerebration, or even reason were substituted.
At first glance it would seem that the study of the sensory elements of
consciousness, motor, tactile, visual, auditory, olfactory, gustatory,
thermal, internal, pursued for the last half century by the experimental
method, would furnish a clue to the nature of the imagination. A visual
image, or mental picture, is popularly taken as characteristic of the
imaginative process. In fact, the distinguished psychologist William
James devotes the whole of his interesting chapter on the imagination to
the discussion of different types of imagery. The sensory elements of
consciousness are involved, however, in perception, memory, volition,
reason, and sentiment, as they are in imagination. They have been
recognized as fundamental from antiquity. Nothing is in the intellect
which was not previously in the senses. To be out of one's senses is to
lack the purposive guidance of the intelligence.
The psychology of individuals and groups shows startling differences in
the kind and vividness of imagery. Many cases are on record where the
mental life is almost exclusively in visual, in auditory, or in motor
terms. One student learns a foreign language by writing out every word
and sentence; another is wholly dependent on hearing them spoken; a
third can recall the printed page with an almost photographic
vividness. The history of literature and art furnishes us with
illustrations of remarkable powers of visualization. Blake and Fromentin
were able to reproduce in pictures scenes long retained in memory. The
latter recognized that his painting was not an exact reproduction of
what he had seen, but that it was none the less artistic because of the
selective influence that his mind had exerted on the memory image.
Wordsworth at times postponed the description of a scene that appealed
to his poetic fancy with the express purpose of blurring the outlines,
but enhancing the personal factor. Goethe had the power to call up at
will the form of a flower, to make it change from one color to another
and to unfold before his mind's eye. Professor Dilthey has collected
many other records of the hallucinatory clearness of the visual imagery
of literary artists.
On the other hand, Galton, after his classical study of mental imagery
(1883), stated that scientific men, as a class, have feeble powers of
visual representation. He had appealed for evidence of visual recall to
distinguished scientists because he thought them more capable than
others of accurately stating the results of their introspection. He had
recourse not only to English but to foreign scientists, including
members of the French Institute. "To my astonishment," he writes, "I
found that the great majority of men of science to whom I first applied
protested that mental imagery was unknown to them, and they looked on me
as fanciful and fantastic in supposing that the words 'mental imagery'
really expressed what I believed everybody supposed them to mean. They
had no more notion of its true nature than a color-blind man, who has
not discerned his defect, has of the nature of color." One scientist
confessed that it was only by a figure of speech that he could describe
his recollection of a scene as a mental image to be perceived with the
mind's eye.
When Galton questioned persons whom he met in general society he found
"an entirely different disposition to prevail. Many men and a yet larger
number of women, and many boys and girls, declared that they habitually
saw mental imagery, and that it was perfectly distinct to them and full
of color." The evidence of this difference between the psychology of the
average distinguished scientist and the average member of general
society was greatly strengthened upon cross-examination. Galton
attributed the difference to the scientist's "habits of highly
generalized and abstract thought, especially when the steps of reasoning
are carried on by words [employed] as symbols."
It is only by the use of words as symbols that scientific thought is
possible. It is through coöperation in work that mankind has imposed its
will upon the creation, and coöperation could not have been carried far
without the development of language as a means of communication. Were it
not for the help of words we should be dependent, like the lower
animals, on the fleeting images of things. We should be bound to the
world of sense and not have range in the world of ideas. Words are a
free medium for thought, for the very reason that they are capable of
shifting their meaning and taking on greater extension or intension. For
example, we may say that the apple falls because it is heavy, or we may
substitute synonymous phraseology that helps us to view the falling
apple in its universal aspects. The mind acquires through language a
field of activity independent of the objective world. We have seen in an
earlier chapter that geometry developed as a science is becoming
gradually weaned from the art of surveying. Triangles and rectangles
cease to suggest meadows, or vineyards, or any definite imagery of that
sort, and are discussed in their abstract relationship. Science demands
the conceptual rather than the merely sensory. The invisible real world
of atoms and corpuscles has its beginning in the reason, the word. To
formulate new truths in the world of ideas is the prerogative of minds
gifted with exceptional reason.
To be sure, language itself may be regarded as imagery. Some persons
visualize every word spoken as though it were seen on the printed page;
others cannot recall a literary passage without motor imagery of the
speech organs or even incipient speech; while others again experience
motor imagery of the writing hand. With many, in all forms of
word-consciousness, the auditory image is predominant. In the sense of
being accompanied by imagery all thinking is imaginative. But it is the
use of words that permits us to escape most completely from the more
primitive forms of intelligence. So directly does the printed word
convey its meaning to the trained mind that to regard it as so much
black on white rather than as a symbol is a rare and rather upsetting
mental experience. Words differ among themselves in their power to
suggest images of the thing symbolized. The word "existence" is less
image-producing than "flower," and "flower" than "red rose." It is
characteristic of the language of science to substitute the abstract or
general expression for the concrete and picturesque.
When, therefore, we are told that the imagination has been at the bottom
of all great scientific discoveries, that the discovery of law is the
peculiar function of the creative imagination, and that all great
scientists have, in a certain sense, been great artists, we are
confronted with a paradox. In what department of thought is imagination
more strictly subordinated than in science? Genetic psychology attempts
to trace the development of mind as a means of adjustment. It examines
the instincts that serve so wonderfully the survival of various species
of insects. It studies the more easily modified instinct of birds, and
notes their ability to make intelligent choice on the basis of
experience. Does the bird's ability to recognize imply the possession of
memory, or imagery? Increased intelligence assures perpetuation of other
species in novel and unforeseen conditions. The more tenacious the
memory, the richer the supply of images, the greater the powers of
adaptation and survival. We know something concerning the motor memory
of rodents and horses, and its biological value. The child inherits less
definitely organized instincts, but greater plasticity, than the lower
animals. Its mental life is a chaos of images. It is the work of
education to discipline as well as to nourish the senses, to teach form
as well as color, to impart the clarifying sense of number, weight, and
measurement, to help distinguish between the dream and the reality, to
teach language, the treasure-house of our traditional wisdom, and logic,
so closely related to the right use of language. The facts of abnormal,
as well as those of animal and child psychology, prove that the
subordination of the imagination and fancy to reason and understanding
is an essential factor in intellectual development.
No one, of course, will claim that the mental activity of the scientific
discoverer is wholly unlike that of any other class of man; but it leads
only to confusion to seek to identify processes so unlike as scientific
generalization and artistic production. The artist's purpose is the
conveyance of a mood. The author of _Macbeth_ employs every device to
impart to the auditor the sense of blood-guiltiness; every lurid scene,
every somber phrase, serves to enhance the sentiment. A certain picture
by Dürer, a certain poem of Browning's, convey in every detail the
feeling of dauntless resolution. Again, a landscape painter, recognizing
that his satisfaction in a certain scene depends upon a stretch of blue
water with a yellow strand and old-gold foliage, proceeds to rearrange
nature for the benefit of the mood he desires to enliven and perpetuate.
It is surely a far cry from the attitude of these artists manipulating
impressions in order to impart to others an individual mood, to that of
the scientific discoverer formulating a law valid for all intellects.
In the psychology of the present day there is much that is reminiscent
of the biological psychology of Aristotle. From the primitive or
nutrient soul which has to do with the vital functions of growth and
reproduction, is developed the sentient soul, concerned with movement
and sensibility. Finally emerges the intellectual and reasoning soul.
These three parts are not mutually exclusive, but the lower foreshadow
the higher and are subsumed in it. Aristotle, however, interpreted the
lower by the higher and not vice versa. It is no compliment to the
scientific discoverer to say that his loftiest intellectual achievement
is closely akin to fiction, or is the result of a mere brooding on
facts, or is accompanied by emotional excitement, or is the work of
blind instinct.
It will be found that scientific discovery, while predominantly an
intellectual process, varies with the nature of the phenomena of the
different sciences and the individual mental differences of the
discoverers. As stated at the outset the psychology of scientific
discovery must be the subject of prolonged investigation, but some data
are already available. One great mathematician, Poincaré, attributes his
discoveries to intuition. The essential idea comes with a sense of
illumination. It is characterized by suddenness, conciseness, and
immediate certainty. It may come unheralded, as he is crossing the
street, walking on the cliffs, or stepping into a carriage. There may
have intervened a considerable period of time free from conscious effort
on the special question involved in the discovery. Poincaré is inclined
to account for these sudden solutions of theoretical difficulties on the
assumption of long periods of previous unconscious work.
There are many such records from men of genius. At the moment the
inventor obtains the solution of his problem his mind may seem to be
least engaged with it. The long-sought-for idea comes like an
inspiration, something freely imparted rather than voluntarily acquired.
No mental process is more worthy to command respect; but it may not lie
beyond the possibility of explanation. Like ethical insight, or
spiritual illumination, the scientific idea comes to those who have
striven for it. The door may open after we have ceased to knock, or the
response come when we have forgotten that we sent in a call; but the
discovery comes only after conscious work. The whole history of science
shows that it is to the worker that the inspiration comes, and that new
ideas develop from old ideas.
It may detract still further from the mysteriousness of the
discovery-process to add that the illuminating idea may come in the
midst of conscious work, and that then also it may appear as a sudden
gift rather than the legitimate outcome of mental effort. The
spontaneity of wit may afford another clue to the mystery of scientific
discovery. The utterer of a witticism is frequently as much surprised by
it as the auditors, probably because the idea comes as verbal imagery,
and the full realization of their significance is grasped only with the
actual utterance of the words. The fact that to the scientific
discoverer the solution of his problem arrives at the moment when it is
least sought is analogous to the common experience that the effort to
recall a name may inhibit the natural association.
The tendency to emphasize unduly the rôle played by the scientific
imagination springs probably from the misconception that the imagination
is a psychological superfluity, one of the luxuries of the mental life,
which should not be withheld from those who deserve the best. The view
lingers with regard to the æsthetic imagination. James could not
understand the biological function of the æsthetic faculty. On the
alleged uselessness of this phase of the human mind A. J. Balfour has
recently based an argument for the immortality of the soul. This view is
strikingly at variance with that which inclines to identify it with that
mental process which creates scientific theories and thus paves the way
for the adjustment of posterity to earthly conditions.
REFERENCES
Baldwin, J. M., _History of Psychology_, 1913. 2 vols.
Dessoir, Max, _Outlines of the History of Psychology_, 1912.
Klemm, Otto, _A History of Psychology_, 1914.
Merz, J. T., _History of European Thought in the Nineteenth Century_,
vol. II, chap. XII, On the Psycho-physical View of Nature.
Rand, Benjamin, _The Classical Psychologists_, 1912.
Ribot, T. A., _English Psychology_, 1889.
Ribot, T. A., _German Psychology of To-day_, 1886.
CHAPTER XX
SCIENCE AND DEMOCRATIC CULTURE
Education is the oversight and guidance of the development of the
immature with certain ethical and social ends in view. Pedagogy,
therefore, is based partly on psychology--which, as we have seen in the
preceding chapter, is closely related to the biological sciences--and
partly on ethics, or the study of morals, closely related to the social
sciences. These two aspects of education, the psychological and the
sociological, were treated respectively in Rousseau's _Emile_ and
Plato's _Republic_. The former ill-understood work, definitely referring
its readers to the latter for the social aspect of education, applies
itself as exclusively as possible to the study of the physical and
mental development of the individual child. Rousseau consciously set
aside the problem of nationality or citizenship; he was cosmopolitan,
and explicitly renounced the idea of planning the education of a
Frenchman or a Swiss. Neither did he desire to set forth the education
of a wild man, free and unrestrained. He wished rather to depict the
development of a natural man in a state of society; but he emphasized
the native hereditary endowment, while expressing his admiration for
Plato's _Republic_ as the great classic of social pedagogy. The titles
of the two works, one from the name of an individual child, the other
from a form of government, should serve to remind us of the purpose and
limitations of each.
Plato's thought was centered on the educational and moral needs of the
city-state of Athens. He was apprehensive that the city was becoming
corrupted through the wantonness and lack of principle of the Athenian
youth. He strove to rebuild on reasoned foundations the sense of social
obligation and responsibility which had in the earlier days of Athens
rested upon faith in the existence of the gods. As a conservative he
hoped to restore the ancient Athenian feeling for duty and moral worth,
and he even envied some of the educational practices of the rival
city-state Sparta, by which the citizen was subordinated to the state.
The novel feature of Plato's pedagogy was the plan to educate the
directing classes, men disciplined in his own philosophical and ethical
conceptions. He was, in fact, an intellectual aristocrat, and spoke of
democracy in very ironical terms, as the following sentences will
show:--
"And thus democracy comes into being after the poor have conquered their
opponents.... And now what is their manner of life, and what sort of a
government have they? For as the government is, such will be the man....
In the first place, are they not free? and the city is full of freedom
and frankness--a man may do as he likes.... And where freedom is, the
individual is clearly able to order his own life as he pleases?... Then
in this kind of State there will be the greatest variety of human
natures?... This then will be the fairest of States, and will appear the
fairest, being spangled with the manners and characters of mankind, like
an embroidered robe which is spangled with every sort of flower. And
just as women and children think variety charming, so there are many
men who will deem this to be the fairest of States.... And is not the
equanimity of the condemned often charming? Under such a government
there are men who, when they have been sentenced to death or exile, stay
where they are and walk about the world; the gentleman [convict] parades
like a hero, as though nobody saw or cared.... See too ... the forgiving
spirit of democracy and the 'don't care' about trifles, and the
disregard of all the fine principles which we solemnly affirmed ... how
grandly does she trample our words under her feet, never giving a
thought to the pursuits which make a statesman, and promoting to honor
anyone who professes to be the people's friend.... These and other
kindred characteristics are proper to democracy, which is a charming
form of government, full of variety and disorder, and dispensing
equality to equals and unequals alike.... Consider now ... what manner
of man the individual is ... he lives through the day indulging the
appetite of the hour; and sometimes he is lapped in drink and strains of
the flute; then he is for total abstinence, and tries to get thin; then,
again, he is at gymnastics; sometimes idling and neglecting everything,
then once more living the life of a philosopher; often he is in
politics, and starts to his feet and says and does whatever comes into
his head; and, if he is emulous of anyone who is a warrior, off he is in
that direction, or of men of business, once more in that. His life has
neither order nor law; so he goes on continually, and he terms this joy
and freedom and happiness. Yes, his life is all liberty and equality.
Yes, ... and multiform, and full of the most various characters; ... he
answers to the State, which we described as fair and spangled.... Let
him then be set over against democracy; he may truly be called the
democratic man."
In spite of the satirical tone of this passage much of it may be
accepted as the unwilling tribute of a hostile critic. Democracy is the
triumph of the masses over the oligarchs. It is merciful in the
administration of justice. It shows a magnanimous spirit and does not
magnify the importance of trifles. It prefers the rule of its friends to
the rule of a despot. Under its government people feel themselves
blessed by happiness, liberty, and equality. The culture of the
democratic man is above all characterized by adaptability.
In the nineteenth century Matthew Arnold, the apostle of culture,
discussing the civilization of a democratic nation of many millions,
unconsciously confirmed the views of Plato in some respects, while
showing interesting points of difference. He expressed his admiration of
the institutions, solid social conditions, freedom and equality, power,
energy, and wealth of the people of the United States. In the daintiness
of American house-architecture, and in the natural manners of the free
and happy American women he saw a real note of civilization. He felt
that his own country had a good deal to learn from America, though he
did not close his eyes to the real dangers to which all democratic
nations are exposed. Arnold failed in his analysis of American
civilization to confirm Plato's judgment concerning the variety of
natures to be found in the democratic State, as well as the Greek
philosopher's censure that democracy shows disregard of ethical
principles. In fact, Arnold considered the people of the United States
singularly homogeneous, singularly free from the distinctions of class;
"we [the English] are so little homogeneous, we are living with a system
of classes so intense, that the whole action of our minds is hampered
and falsened by it; we are in consequence wanting in lucidity, we do not
see clear or think straight, and the Americans have here much the
advantage of us." As for the second point of difference between Arnold
and Plato, the English critic recognized that the American people
belonged to the great class in society in which the sense of conduct and
regard for ethical principles are particularly developed.
Nearly all the old charges against American democracy can be
summarized in one general censure,--the lack of calm and reasoned
self-criticism,--and this general defect is rapidly being made good. It
is partly owing to charity and good-will, and it includes the toleration
of the mediocre or inferior, as, for example, in the theater; the
failure to recognize distinction, and to pay deference to things
deserving it; the glorification of the average man, and the _hustler_,
and the lack of special educational opportunities for the exceptionally
gifted child. That criticism as an art is still somewhat behindhand in
America seems to be confirmed by comparing French and American literary
criticism. In France it is a profession practiced by a corps of experts;
in America only a very few of the best periodicals can be relied on to
give reviews based on critical principles, of works in verse or prose.
(One American reviewer confesses that in a single day he has written
notices of twenty new works of fiction, his work bringing him, as
remuneration, seventy-five cents a volume.)
There is no evidence, however, that Americans as individuals are wanting
in the self-critical spirit. And for Arnold this is vital, seeing that
the watchword of the culture he proclaims is Know Thyself. It is not a
question of gaining a social advantage by a smattering of foreign
languages. It is more than intellectual curiosity. "Culture is more
properly described as having its origin in the love of perfection. It
moves by the force, not merely or primarily of the scientific passion
for pure knowledge, but also of the passion for doing good." Human
perfection, the essence of culture, is an internal condition, but the
will to do good must be guided by the knowledge of what is good to do;
"acting and instituting are of little use unless we know how and what we
ought to act and institute." Moreover, "because men are all members of
one great whole, and the sympathy which is human nature will not allow
one member to be indifferent to the rest, the expansion of our humanity,
to suit the idea of perfection which culture forms, must be a _general_
expansion."
For Arnold's contemporary Nietzsche, the German exponent of Aristocracy,
the _expansion_ of education entailed its diminution. For him ancient
Greece was the only home of culture, and such culture was not for all
comers. The rights of genius are not to be democratized; not the
education of the masses, but rather the education of a few picked men
must be the aim. The one purpose which education should most zealously
strive to achieve is the suppression of all ridiculous claims to
independent judgment, and the inculcation upon young men of obedience to
the scepter of genius. The scientific man and the cultured man belong to
two different spheres which, though coming together at times in the same
individual, are never fully reconciled.
In order to appreciate the full perverseness, from the democratic
standpoint, of Nietzsche's view of culture, it is necessary to glance
at his political ideals as explained by one of his sponsors.
Nietzsche repudiates the usual conception of morality, which he calls
slave-morality, in favor of a morality of masters. The former according
to him encourages the deterioration of humanity; the latter promotes
advancement. He favors a true aristocracy as the best means of producing
a race of supermen. "Instead of advocating 'equal and inalienable rights
to life, liberty, and the pursuit of happiness,' for which there is at
present such an outcry (a régime which necessarily elevates fools and
knaves, and lowers the honest and intelligent), Nietzsche advocates
simple _justice_--to individuals and families according to their
_merits_, according to their worth to society; _not_ equal rights,
therefore, but unequal rights, and inequality in advantages generally,
approximately proportionate to deserts; consequently, therefore, a
genuinely superior ruling class at one end of the social scale, and an
actually inferior ruled class, with slaves at its basis, at the opposite
social extreme."
Since it is the view of this aristocratic philosopher that science is
the ally of democracy--a view that every chapter of the history of
science serves to demonstrate--it is of interest to review his opinion
of the character of the scientist. For Nietzsche the scientist is not a
heroic superman, but a commonplace type of man, with commonplace
virtues. He lacks domination, authority, self-sufficiency; he is rather
in need of recognition from others and is characterized by the
self-distrust innate in all dependent men and gregarious animals. He is
industrious, patiently adaptable to rank and file, equable and moderate
in capacity and requirement. He has a natural feeling for people like
himself, and for that which they require: A fair competence and the
green meadow without which there is no rest from labor. The scientist
shows no rapture for exalted views; in fact, with an instinct for
mediocrity, he is envious and strives for the destruction of the
exceptional man.
A training in natural science tends to make one objective. But the
objective man, in Nietzsche's opinion, distrusts his own personality and
regards it as something to be set aside as accidental, and a detriment
to calm judgment. The temperamental philosopher thinks the scientist
serene, but that his serenity springs not from lack of trouble, but from
incapacity to grasp and deal with his own private grief. His is merely
disinterested knowledge, according to Nietzsche. The scientist is
emotionally impoverished. His love is constrained, and his hatred
artificial; he is less interesting to women than the warrior. "His
mirroring and externally self-polished soul no longer knows how to
affirm, no longer how to deny; he does not command; neither does he
destroy." As we see in the case of Leibnitz, the scientist contemns
scarcely anything (_Je ne méprise presque rien_). The scientist is an
instrument, but not a goal; he is something of a slave, nothing in
himself--_presque rien!_ There is in the scientist nothing bold,
powerful, self-centered, that wants to be master. He is for the most
part a man without content and definite outline, a selfless man.
This educational product, which the builders of modern aristocracy
reject, and describe after their fashion, we accept as the ally of the
masses of the people, and we term it democratic culture.
The objective man, at the same time, may find even in the vehement pages
of Nietzsche warnings and criticisms which the friends of democracy
should not disregard. Extreme, almost insane, as his doctrine
undoubtedly is, it may have value as a corrective influence, an antidote
for other extreme views. It serves to remind us that democracy may be
misled by feelings in themselves noble, and may, by grasping what seems
good, miss what is best. For example, there are in the United States
about three hundred thousand persons, defective or subnormal mentally;
there is a smaller number of persons exceptionally gifted mentally. It
is a poor form of social service that would exhaust the resources of
science and philanthropy to care for the former without making any
special provision for the latter. Genius is too great an asset to be
wasted or misapplied. All culture would have suffered if Newton had been
held, in his early life, to exacting administrative work; or if Darwin
had devoted his years to alleviating the conditions of the miners of
Peru whose misery touched him so profoundly; or if Pasteur had been
taken from the laboratory and pure science to make a country doctor. Nor
can democracy rest satisfied with any substitute for culture which would
disregard what is great in literature, in art, and in philosophy, or
which would ignore history, and the languages and civilizations of the
past, as if culture had its beginning yesterday.
In this chapter we have considered democracy and democratic culture from
the standpoint of three writers on education, a Greek aristocrat, a
German advocate of the domination of the classes over the masses, and an
Oxford professor, all by training and temperament more or less hostile
critics. A more direct procedure might have been employed to establish
the claim of science to afford a basis of intellectual and social
homogeneity. A brilliant literary man of the present day considers that
places in the first ranks of literature are reserved for the doctrinally
heterodox. None of the great writers of Europe, he asserts, have been
the adherents of the traditional faith. (He makes an exception in favor
of Racine: but this is a needless concession, for Racine owed his early
education to the Port Royalists, became alienated from them and wrote
under the inspiration of the idea of the moral sufficiency of worldly
honor; then, after an experience that shook his faith in his own code,
he returned to the early religious influences in his life and composed
his _Esther_ and _Athalie_.) But, unlike literature, the study of
science is not exclusive. In the front ranks of science stand the devout
Roman Catholic Pasteur, the Anglican Darwin, the Unitarian Priestley,
the Calvinist Faraday, the Quakers Dalton, Young, and Lister, Huxley
the Agnostic, and Aristotle the pagan biologist. Science has no Test
Acts.
That the cultivation of the sciences tends to promote a type of culture
that is democratic rather than aristocratic, sympathetic rather than
austere, inclusive rather than exclusive, is further witnessed by the
fact that the tradesman and artisan, as well as the dissenter, play a
large part in their development. We have seen that Pasteur was the son
of a tanner, Priestley of a cloth-maker, Dalton of a weaver, Lambert of
a tailor, Kant of a saddler, Watt of a shipbuilder, Smith of a farmer.
John Ray was, like Faraday, the son of a blacksmith. Joule was a brewer.
Davy, Scheele, Dumas, Balard, Liebig, Wöhler, and a number of other
distinguished chemists, were apothecaries' apprentices. Franklin was a
printer. At the same time other ranks of society are represented in the
history of science by Boyle, Cavendish, Lavoisier. The physicians and
the sons of physicians have borne a particularly honorable part in the
advancement of physical as well as mental science. The instinctive
craving for power, the will to dominate, of which Nietzsche was the
lyricist, was in these men subdued to patience, industry, and
philanthropy. The beneficent effect of their activities on the health
and general welfare of the masses of the people bears witness to the
sanity and worth of the culture that prompted these activities.
As was stated at the outset of this chapter, education is the oversight
and guidance of the development of the immature with certain ethical and
social ends in view. The material of instruction, the method of
instruction, and the type of educational institution, will vary with
the hereditary endowment, age, and probable social destiny of the child.
In a democratic country likely to become more, rather than less,
democratic, those subjects will naturally be taught which have vital
connection with the people's welfare and progress in civilization. At
the same time the method of instruction will be less dogmatic and more
inclined (under a free than under an absolute government) to evoke the
child's powers of individual judgment; arbitrary discipline must yield
gradually to self-discipline. The changes here indicated as desirable
are already well under way in America. As regards types of educational
institution, it is significant that America about the middle of the
eighteenth century introduced the Miltonic, nonconformist Academy, with
its science curriculum, in place of the traditional Latin grammar
school. Later the American high school, institutions of which type now
have over a million pupils, and teach science by the heuristic
laboratory method, became the popular form of secondary school. It is,
likewise, not without social significance that the Kindergarten was
suppressed in Prussia after the revolt of the people in the middle of
the nineteenth century, and that it found a more congenial home in a
democratic country. Its educational ideal of developing self-activity
without losing sight of the need of social adaptation finds its
corollary in systematic teaching of the sciences in relation both to the
daily work and to their historical and cultural antecedents.
REFERENCES
Matthew Arnold, _Essays in Criticism_, and _Culture and Anarchy_.
Matthew Arnold, _Civilization in the United States_.
Friedrich Nietzsche, _On the Future of our Educational Institutions_,
vol. VI. of the _Complete Works_; translation edited by Dr. Oscar
Levy.
Friedrich Nietzsche, _Beyond Good and Evil_, vol. V, chap. VI. of the
_Complete Works_.
Plato, _Republic_, Book VIII; vol. III. of Benjamin Jowett's
translation of the _Dialogues of Plato_, 1875.
INDEX
Académie des Sciences, 111, 112.
Academy, at Athens, 19;
Milton's plan, 102;
Defoe's, 116;
Franklin's, 125;
type of secondary school, 282.
Adams, John Couch, 188 _et seq._
Aerodynamics, 233.
Agricola, George, 129.
Agriculture, 12, 38, 107, 126, 137.
Air, 157.
Air craft, 71, 126, 231 _et seq._
Air-pump, 96.
Akademie der Wissenschaften, 113.
Albertus Magnus, 53.
Alchemy, 50, 252.
Alcuin, 52.
Alexandria, 19, 44 _et seq._
Algebra, 49.
Alkaline earths, 179.
American Philosophical Society, 121.
Anatomy, 6, 8, 38, 50, 78.
Anemometer, 107, 235.
Anthrax, 224 _et seq._
Antipodes, 37, 48.
Antiseptic surgery, 220, 231.
Application, 30 _et seq._
_Aqua regia_, 51, 132.
Aqueducts, 33.
Aqueous vapor, 157 _et seq._
Arago, 184.
Archimedes, 27.
Architecture, 30 _et seq._
Archytas, 18.
Aristotle, 20 _et seq._, 49, 51, 53, 266.
Arithmetic, 6, 11, 48.
Arnold, Matthew, 273.
Astrology, 10.
Astronomy, (Egyptian and Babylonian) 2 _et seq._;
(Greek) 16;
(Roman) 34;
(Alexandrian) 45;
(Hindu) 48;
(Arabian) 49, 50;
(Copernican) 55;
(Tycho Brahe and Kepler) 87 _et seq._;
(Newton) 110 _et seq._;
(nebular hypothesis) 142 _et seq._;
(discovery of Neptune) 184 _et seq._
Atmosphere, 157.
Atomic Theory, 158 _et seq._, 250.
Atoms, 17, 148, 158, 253.
Augustus Cæsar, 36.
Averroës, 51 _et seq._
Avicenna, 51.
Avogadro, 165.
Babylonia, 1 _et seq._
Bacon, Francis, 57 _et seq._, 80 _et seq._, 105;
Baconian principles, 211.
Bacon, Roger, 54.
Bacteria, 93.
Bacteriology, 213 _et seq._
Bagdad, 49.
Barbarians, 46.
Barometer, 94 _et seq._
Basalt, 131, 132, 136, 137, 201.
Becquerel, 233, 246 _et seq._
Beddoes, 173.
Beer, 223, 226.
Berzelius, 162.
Bessel, 187.
Biology, 6, 7, 23 _et seq._, 37, 53, 78, 109, 197 _et seq._, 213.
Biot, 215 _et seq._
Black, 129, 133.
_Bode's Law_, 189.
Botany, 6, 26, 37, 39, 53, 231 _et seq._
Bouvard, Alexis, 185.
Bouvard, Eugène, 187.
Boyle, 96, 107.
Buffon, 130, 135.
Building material, 32.
Cabanis, 258.
Cairo, 49.
Calendar, 9, 36.
Carbonic acid, 138, 155, 157, 217.
Carlisle, 177.
Cato, 35, 38.
Challis, 189.
Charlemagne, 52.
Charles II, 105.
Chemical affinity, 159, 253.
Chemistry, 6, 8, 50, 51, 155 _et seq._, 170 _et seq._, 245 _et seq._
Chicken cholera, 225.
Chlorine, 180.
Clocks, 89, 94.
Collinson, 123.
Columbus, 26, 54.
Columella, 38.
Comenius, 100.
Comets, 10, 40, 149.
Conservation of energy, 168.
Constantine, 37.
Copernicus, 55.
Coral reefs, 203.
Cordova, 50.
Counting, 6, 11, 34, 49, 86.
Cowley, 104 _et seq._
Cronstedt, 130.
Curie, P. and S., 247 _et seq._
D'Alembert, 58.
Dalton, 155, 157 _et seq._
Darwin, Charles, 198 _et seq._
Darwin, Erasmus, 199.
Davy, 122, 163, 170 _et seq._
Deduction, 82.
Defoe, 116.
Democratic culture, 44, 270 _et seq._
Democritus, 17, 48, 148.
Descartes, 57, 72, 82 _et seq._
Desmarest, 132.
_Dialogues_ of Plato, 19.
Diderot, 58.
Dioscorides, 39.
Dyes, 24, 33, 71, 181.
Earthquakes, 40, 137.
Ebers papyrus, 7.
Eclipses, 10, 16, 49.
Education, 19, 35, 36, 40, 44, 52, 53, 100 _et seq._, 116, 122, 123,
171-72, 198, 213, 214, 216, 270 _et seq._
Egypt, 1 _et seq._
Electricity, 75, 123 _et seq._, 177, 231.
Electrolysis, 178.
Elements, 17, 20, 22, 155.
Ellipse, 20.
Embalmers, 7.
Empedocles, 17, 40.
_Encyclopaedia_, 58.
Ethics, 21, 40, 41.
Euclid, 18, 19.
Evelyn, 109.
Experiment, 72 _et seq._
Extinction, 206.
Faraday, 181.
Fermentation, 216 _et seq._
Fitzroy, 198.
Flacherie, 221.
Flamsteed, 110, 111, 184.
Fossils, 140.
Franklin, 15, 114.
Galen, 38, 79.
Galileo, 75 _et seq._, 95.
Galapagos Archipelago, 208 _et seq._
Galle, 193.
Galton, 258.
Galvani, 177.
Gascoigne, 93.
Gassendi, 99.
Gay-Lussac, 164, 181.
Geber, 177.
Geology, 129 _et seq._
Geometry, 4, 15, 18, 19, 84, 264.
Gerbert, 53.
Gilbert, 72, 74, 76.
Glen Tilt, 136.
Gnomon, 13, 33.
Granite, 131.
Graunt, 105, 109.
Gravity, 110 _et seq._
Greece, 15 _et seq._
Gresham College, 101, 106.
Grew, 109.
Guericke, 96.
Hall, Sir James, 129, 137 _et seq._
Halley, 110, 112, 186.
Hammurabi, 12.
Hartley, 172, 258.
Hartlib, 99.
Harun Al-Rashid, 48.
Heat, 82, 155, 156, 166, 168, 173.
Heliacal rising, 4.
Helmholtz, 168, 258.
Henry, 238.
Heraclitus, 17.
Herschel, Sir John, 192.
Herschel, Sir William, 152 _et seq._, 184.
Hindu arithmetic and astronomy, 48, 49.
Hipparchus, 27, 45.
Hippocrates, 27.
Hobbes, 99.
Homology, 26.
Hooke, 107, 109.
Hope, 138.
Horrocks, 109.
Horse, 204.
Horticulture, 40.
Hugo of St. Victor, 60.
Humboldt, 131, 201.
Hussey, 186.
Hutton, 132 _et seq._
Huygens, 94, 111.
Hydrophobia, 207, 227 _et seq._
Hypatia, 46, 48.
Hypothesis, 147, 150, 245 _et seq._
I-em-hetep, 6.
Ilu-bani, 12.
Induction, 81, 177.
Industries, 8, 27, 68 _et seq._, 173, 182, 220, 223, 226.
Inoculation, 126.
Inventions, 107, 233 _et seq._
Invisible College, 103.
Iodine, 181.
Iron, 8, 13, 182.
Isidore of Seville, 60.
James, William, 258, 261, 268.
Joule, 155, 167 _et seq._
Julius Cæsar, 36.
Kant, 142, 145 _et seq._
Kepler, 90 _et seq._, 110.
Kindergarten, 281.
Kircher, 93.
Lactantius, 48.
Lambert, 142, 149 _et seq._
Langley, 231 _et seq._
Laplace, 112, 150 _et seq._
Laurium, 27.
Lava, 138.
Lavoisier, 156, 172.
Leeuwenhoek, 93.
Leibnitz, 106, 112, 277.
Lenses, 40, 50.
Leonardo da Vinci, 72.
Leverrier, 190 _et seq._
Libraries, 46, 48, 121.
Lincoln, 43 _et seq._
Linnæus, 130.
Lippershey, 92.
Lister, 213, 220, 223.
Locke, 116, 172, 258.
Logarithms, 91.
Logic, 21, 53.
Lucretius, 40.
Lyell, 197, 201.
Magnetism, 75, 127.
Magnifiers, 40.
Malpighi, 93, 106, 109.
Malthus, 121, 211.
Manchester, 157.
Marble, 139.
Mars, 10, 91.
Marsh gas, 126, 163, 182.
Materia medica, 39, 51.
Mathematics, 4, 5, 6, 10, 11, 15, 17, 18, 19, 34, 48, 49, 55,
87 _et seq._, 110 _et seq._, 184 _et seq._, 264.
Maupertuis, 145.
Mayow, 156.
Measuring, 5, 10, 86 _et seq._
Mechanics, 18, 77, 231 _et seq._
Medicine, 6, 11, 27, 34, 126, 173 _et seq._, 207, 216 _et seq._
Mensuration, 5, 92.
Mental imagery, 263.
Mercury, 50, 51, 156.
Mersenne, 99, 112.
Metallurgy, 8, 13, 23, 50.
Meteorology, 122, 133, 158.
Microscope, 93.
Milky Way, 144.
Mill, John Stuart, 256.
Milton, 102, 213.
Mineralogy, 130.
Minute and second, 46.
Monochord, 17.
Monte Cassino, 52.
Moray, 104, 112.
Murex, 24, 33.
Napier, 91.
Napoleon I, 151, 177, 214.
Napoleon III, 221.
Natural history, 23, 37, 52, 61.
Navigation, 3, 16, 26, 54, 126, 231.
Nebular hypothesis, 147, 150.
Neptune, 184 _et seq._
Neptunist, 131.
_New Atlantis_, 71, 100, 183.
Newton, 110, 135, 158.
Nicholson, 177.
Nietzsche, 277 _et seq._
Nitric oxide, 156, 161.
Nitrous oxide, 174.
_Novum Organum_, 70, 72.
Numerals, 6, 11, 34, 49, 87, 231.
Observatories, 4, 49.
Occupations, 12, 51, 58, 68 _et seq._, 107.
Optics, 50, 54, 93.
Organic remains, 126, 140.
Origin of the sciences, 1 _et seq._
_Origin of Species_, 201.
Pansophy, 100.
Pascal, 95, 117.
Pasteur, 213 _et seq._
Pearson, Karl, 60.
Peirce, 195.
Pepys, 110.
Petty, 103, 122.
Peurbach, 55.
_Philosophical Transactions_, 109.
Philosophy, 15 _et seq._, 134.
Physics, 21, 28, 31, 32, 50, 54, 74 _et seq._, 94 _et seq._,
110 _et seq._, 128, 155 _et seq._, 170 _et seq._, 231 _et seq._,
245 _et seq._
Physiology, 6, 21, 38, 78, 173 _et seq._, 225 _et seq._
Picard, 111.
Plato, 18, 270 _et seq._
Playfair, 133, 137.
Pliny, 37.
Pneumatic Institution, 173.
Poincaré, Henri, 255, 267.
Port Royal, 116, 279.
Potash, 23, 51, 179.
Potassium, 179.
Precession of the equinoxes, 10, 112.
Priestley, 126, 156.
Primitive man, 206.
_Principia_, 110, 114.
Prism, 40.
_Protyl_, 254.
Psychology, 23, 256 _et seq._
Ptolemy, 45, 55.
Pythagoras, 17.
Quadrants, 50, 86.
Quintilian, 39.
Rabies, 227 _et seq._
Racemic acid, 215.
Radioactivity, 245 _et seq._
Ramsay, 246.
Ray, 110.
Regiomontanus, 55.
Religion, 3, 8, 10, 40, 43 _et seq._, 142 _et seq._
Rey, 94.
Rhind papyrus, 6.
Röntgen rays, 231.
Rousseau, 270.
Royal Institution, 176.
Royal Society of Edinburgh, 133.
Royal Society of London, 99 _et seq._
Rumford, 166.
Rutherford, 247 _et seq._
St. Benedict, 52.
St. Thomas Aquinas, 53.
Saturn, 2, 92, 145.
Saussure, 133.
Scheele, 156, 180.
Scientific apparatus, 17, 49, 86 _et seq._
Scotus Erigena, 53.
Seneca, 40.
Shaftesbury, 117.
Signs of zodiac, 9, 33.
Silkworm, 109, 221 _et seq._
Siphon, 95.
Sirius, 4.
Smith, Adam, 121, 133, 256.
Smith, William, 139 _et seq._
Smithsonian Institution, 195, 233, 238.
Socrates, 44, 117.
Soda, 8, 51, 179.
Soddy, 248 _et seq._
Sodium, 179.
Sosigenes, 36.
Sound, 33.
Species, 24, 197 _et seq._
Specific gravity, 28, 36, 50.
Spectrum analysis, 153, 231.
Sphericity of the earth, 26, 37.
Spontaneous generation, 25, 218.
Sprat, 105, 109.
Steel, 8, 23.
Sundial, 13.
Survival, 206.
_Syntaxis_, 45.
Tables, astronomical, 49, 50, 91, 185 _et seq._
Tanning, 177.
Technology, 5, 16, 20, 27, 30 _et seq._, 50, 68 _et seq._, 86 _et seq._,
103, 107, 126, 129, 130, 139-41, 156, 160, 167, 177, 182, 231.
Thales, 15.
Theology, 47, 62, 172.
Theon, 46.
Theophrastus, 26, 39.
Theory, 30, 41; _T. of the Earth_, 133.
Tides, 38, 112.
Torricelli, 95.
Trade and trades, 12, 51, 68 _et seq._, 107, 115, 118.
Transformation Theory, 249 _et seq._
Trigonometry, 46, 49, 55.
Turgot, 121.
Tycho Brahe, 87 _et seq._
Tyndall, 260-61.
Uranus, 184 _et seq._
Vacuum, 95.
Varro, 38.
Vesalius, 78.
Vitruvius, 30 _et seq._
Viviani, 94.
Vivisection, 38, 71, 80.
Volcanoes, 40, 136.
Volta, 177.
Vulcanist, 131, 137.
Wadham College, 104.
Walker, 195.
Wallace, 211, 231.
Wallis, 103.
War, 46, 178, 213 _et seq._
War-engines, 28, 34.
Watch, 94.
Water, 157, 177.
Water-clocks, 13, 94.
Watt, Gregory, 172.
Watt, James, 133, 156, 157.
Wedgwoods, 138, 173, 199.
Weighing, 7, 10, 86.
Werner, 129 _et seq._
Wilkins, 101, 104.
Willis, 104.
Willughby, 109, 110.
Wine, 220, 226.
Wollaston, 119.
Wool, 226.
Wren, 104, 107.
Wright, 143 _et seq._
Wundt, 258, 259.
Xenophon, 117.
Young, 258, 279.
Zacharias, 92.
Zodiac, 9, 33.
Zoölogy, 7, 12, 21, 24, 25, 37, 53, 66, 109, 110, 197 _et seq._
* * * * * *
Transcriber's note:
The following is a list of changes made to the original.
The first line is the original line, the second the corrected one.
parabola, hyperbola--play a large part in the subsequent
parabola, the hyperbola--play a large part in the subsequent
Seneca, _Physcial Science_; translated by John Clarke.
Seneca, _Physical Science_; translated by John Clarke.
College by 1558 it was the custom to remain for discussion
College by 1658 it was the custom to remain for discussion
slowly with the result that it had a stony, rather a
slowly with the result that it had a stony, rather than a
This would correspond to 325° January 1, 1847.
This would correspond to 325° on January 1, 1847.
sometimes, in the case of the γ rays with velocity
sometimes, in the case of the γ rays, with velocity
positively and negatively chasged particles. Rutherford
positively and negatively charged particles. Rutherford
***
