Matter, Ether, and Motion, Rev. ed., enl.
The Factors and Relations of Physical Science

By Amos Emerson Dolbear

PREFACE TO THE SECOND EDITION
The issue of a new edition of this book gives me
an opportunity to make some needed corrections, and
enlarge it by the addition of three new chapters, which
I hope will make it more useful to such as have a taste
for fundamental physical problems. The first of these,
Properties of Matter as Modes of Motion, presents
the evidence that all the characteristic properties of
matter are due to energy embodied in various forms of
motion. The second, on The Implications of Physical
Phenomena, points out what assumptions are made
in explaining phenomena. It is the substance of a
series of articles published in the Psychical Review in
1892 and 1893. The third, on The Relations between
Physical and Psychical Phenomena, was read as a paper
before the Psychical Congress at the World’s Fair in
August, 1893.
Judging from some of the comments made about
my statements as to Modern Geometry on page 67,
and as to Vital Force, p. 336, I have thought it would
be useful to some to see corroboratory statements;
and I have therefore added, in an appendix, a few
iii
PREFACE TO THE SECOND EDITION iv
pages of quotations from some of the most eminent
mathematicians and biologists on these subjects, and
from them one may judge whether or not my statements
are correct.
As the work is a treatise on Physics, there is
no special reason for going beyond it; but if this
presentation of the subject is any approach to the truth,
there is an important conclusion to be drawn from it.
If the ether be the homogeneous and uniform medium
it is believed with reason to be, then, in the absence of
what we call matter, no physical change which we call
a phenomenon could possibly arise in it; for every such
phenomenon is a product, and in the absence of one
of the essential factors, viz., matter, it could not be. If
matter itself be a form of motion of the ether, the ether
must have existed prior to matter; also, if the atom be
a form of energy, then must energy have existed before
matter existed. Hence there must have been some other
agency radically different from any physical energy we
know, and independent of everything we know, which
was capable of producing orderly physical phenomena,
by acting upon the ether; for a homogeneous medium
could not originate it. Some philosophers call this
antecedent power The Unknowable; others call it God.
If energy as we know it implies antecedent energy as we
do not know it, so, likewise, mind as we know it implies
PREFACE TO THE SECOND EDITION v
antecedent mind under totally different conditions from
those in which we find it embodied.
In whatever direction one pursues physical science,
he is at last confronted with a physical phenomenon with
a superphysical antecedent where all physical methods
of investigation are impotent. Such considerations raise
the theistic hypothesis of creation to the rank of such
physical theories as the nebula theory of the origin of
the solar system, and the undulatory theory of light.
PREFACE
Within the past fifty years the advance in physical
knowledge has not only been rapid, but it has been
well-nigh revolutionary. Not that knowledge that was
felt to be well grounded before has been set aside,—for
it has not been,—but the fundamental principles of
natural philosophy that were applied by Sir Isaac
Newton and others to masses of visible magnitude
have been applied to molecules; and it has thus been
discovered that all kinds of phenomena are subject
to the same mechanical laws. It was thought before
that physics embraced several distinct provinces of
knowledge which were not necessarily related to each
other, such as mechanics, heat, electricity, etc. Such
terms as imponderable matter, latent heat, electric fluid,
forces of nature, and others in common use in text-books
and elsewhere, served to maintain the distinctions; and
even to-day some of these obsolete physical agencies
are to be met in books and places where one would
hope not to find them. As all physical phenomena are
reducible to the principles of mechanics, atoms and
molecules are subject to them as much as masses of
vi
PREFACE vii
visible magnitude; and it has become apparent that
however different one phenomenon is from another, the
factors of both are the same,—matter, ether, and motion;
so that all the so-called forces of nature, considered
as objective things controlling phenomena, are seen to
have no existence; that all phenomena are reducible to
nothing more mysterious than a push or a pull.
Some say that science is simply classified knowledge.
To the author it is more than that, it is a consistent
body of knowledge; and a true explanation of any
phenomenon cannot be inconsistent with the best
established body of knowledge we have. If physical
factors are fundamental, then theorizers must square
their theories to them.
The text-books have not kept pace with the advance
of knowledge; and there is a large body of persons
desirous of knowing more of natural philosophy, and
especially of its trend, who have neither time nor
opportunity to read and digest monographs on a
thousand topics. To meet the wants of such, this
book has been written. It undertakes to present in a
systematic way the mechanical principles that underlie
the phenomena in each of the different departments of
the science, in a readable form, and in an untechnical
manner. The aim has been to simplify and reduce to
mechanical conceptions wherever it was possible to do
PREFACE viii
so.
One may often hear the question asked, What is
electricity? but a similar question as to the nature of
heat or light or chemism is just as pertinent, although
there chances now to be less popular interest in these
than in the former; not, however, because they are in
themselves better understood, or less interesting.
It is hoped that some of those whose interests
lie along such special lines as chemistry, electricity,
and even biology, will find something helpful in the
chapters dealing with those subjects.
In covering so much ground in so small a treatise,
it was necessary to select such facts as give prominence
to fundamental principles. Doubtless others might have
selected different materials, even with the same end
in view, for otherwise competent persons are generally
more familiar with certain details of a given science
than with others; and I have used what was closest at
hand.
Aside from the topics usually treated upon in a book
of physics, the reader will find a chapter on Physical
Fields, which is unique, as it extends the principle
of sympathetic action—recognized in acoustics—to the
whole range of phenomena, including living things.
The chapter on Life, in a treatise on physics, must
justify itself; while the one on Machines points out
their functions in a more complete way than has been
done before.
Lastly, however large the physical universe may
be, and however exact such relations as we have
established may be, it is daily becoming more certain
that even in the physical universe we have to do with
a factor,—the ether,—the properties of which we vainly
strive to interpret in terms of matter, the undiscovered
properties of which ought to warn every one against
the danger of strongly asserting what is possible and
what impossible in the nature of things. With the
electro-magnetic theory of light now just established,
and the vortex ring theory of matter still sub judice, but
with daily increasing evidence in its favor, one may
now be sure that matter itself is more wonderful than
any philosopher ever thought. Its possibilities may
have been vastly underrated.
In the book called “The Unseen Universe,” it is
pointed out that possibly the ether may be the medium
through which mind and matter re-act. What fifteen
years ago was deemed possible, is to-day deemed
probable, and to-morrow may be demonstrated; and a
perusal of that book is recommended to persons who
are interested in questions of that kind.
CONTENTS
CHAPTER PAGE
I. Matter and Its Properties . . . . . . . . 1
II. The Ether . . . . . . . . . . . . . 30
III. Motion . . . . . . . . . . . . . . 52
IV. Energy . . . . . . . . . . . . . . 70
V. Gravitation . . . . . . . . . . . . 99
VI. Heat . . . . . . . . . . . . . . 118
VII. Ether Waves . . . . . . . . . . . . 160
VIII. Electricity . . . . . . . . . . . . 207
IX. Chemism . . . . . . . . . . . . . 286
X. Sound . . . . . . . . . . . . . . 310
XI. Life . . . . . . . . . . . . . . . 336
XII. Physical Fields . . . . . . . . . . . 362
XIII. On Machines.—Mechanism . . . . . . . . 379
XIV. Properties of Matter as Modes of Motion . . . 401
XV. Implications of Physical Phenomena . . . . . 428
XVI. The Relations of Physical and Psychical Phenomena 463
Appendix . . . . . . . . . . . . . 477
Index . . . . . . . . . . . . . . 485
MATTER, ETHER, AND MOTION
CHAPTER I
Matter and Its Properties
All kinds of phenomena that we can become
conscious of through any of our senses are traceable
directly or indirectly to what we call matter. The sense
of feeling implies contact with a body of some kind;
the sense of hearing depends upon movements of the
air, which is a body of matter having certain properties;
and the sense of sight, also due to vibratory motion,
implies that matter exists, however distant, which has
given rise to the vibratory motions that are perceived
as light. So of taste and smell, actual contact of
material particles endowed with particular properties
are the conditions for exciting these sense perceptions.
Some philosophers have added a sixth sense to the
five senses we have recognized for so long a time—the
sense of weight, as distinguished from the sense of
touch; and still others have thought to distinguish
a sense of temperature—relative perceptions of heat
1
MATTER, ETHER, AND MOTION 2
and cold, from the sense of touch; and if these truly
represent distinct senses, they illustrate still further the
truth that it is through the reactions of matter upon
the nervous organizations of living things that all of
our knowledge of things about us and of the universe
as a whole is obtained.
It might seem to one as if our knowledge of matter
should be tolerably good, accurate, and complete,
seeing that it is thrust upon us everywhere, and affects
us for good or evil continuously from the dawn of
sensation till death; yet it may truly be said that the
knowledge of matter, its properties, and the wonderful
complexity of phenomena that are due to them, which
we possess to-day was wholly unknown to all mankind
until the time of Sir Isaac Newton, whose discovery
of the law of gravitation was the first discovery of
a universal property of matter; and by far the larger
part of the knowledge we have, has been acquired in
this century and mostly within the last half of it. The
mass of mankind is, as it always has been, without
any knowledge at all and without any desire for it.
Whatever we have is due to the work of a small
number of persons in Western Europe and America.
Probably the large majority of mankind are quite unable
to understand phenomena and their significance, yet
among the brighter and more competent individuals in
MATTER AND ITS PROPERTIES 3
every country there is an apathy and indifference to
the subject, due, of course, to the estimate they have
of its degree of importance; and this estimate is in
a good measure due to the philosophy of things in
general held by the individual thinkers.
When Mr. Emerson was told by a Millenarian that
the world was coming to an end the next day, he
declared that he could get along without it, and so it
probably has seemed to the majority of philosophers
that the material world was a condition of things to
be endured, rather than to be understood and utilized:
that they were in it but were not a part of it.
Knowledge has, however, increased, and the wise
ones are growing wiser; and some of the modern
questions of philosophy and psychology are now so
woven in with physical details that a knowledge
of matter and its possibilities has become to them
imperative.
There have been many attempts to define matter,
such as, whatever occupies space, or whatever affects
our senses, and so on; and there is no brief definition
that has been generally adopted. In the ordinary affairs
of life one rarely needs to make such distinctions as are
necessary in philosophical and scientific affairs, where
accuracy and clearness are of the utmost importance.
There seems to be no way to define matter except
MATTER, ETHER, AND MOTION 4
by means of some of its properties. If we say that
it is whatever occupies space, there is implied in
the statement that the term is properly applicable to
everything that exists in space; but so far as we know
there may be any number of things in illimitable space
that are not subject to any of the physical laws, such
as a piece of wood or an air particle are known to be
controlled by. If we say whatever affects our senses, we
again are going beyond our warrant; for electricity is
capable of affecting several of our senses,—sight, taste,
feeling,—and yet there is no good reason for thinking
electricity to be matter.
There is one property of matter that may seem
to differentiate it from everything else, and hence, if
adopted, will enable one to be precise about his use of
the term. One part of the law of universal gravitation
is—every particle of matter in the universe attracts every other
particle. This makes gravitation a universal property of
matter. The astronomers have observed the movements
of exceedingly distant stars to be in accordance with
this law, and there are no exceptions to it that have
been discovered.
If, then, one adopts as the definition of matter,
whatever possesses the property of gravitative attraction, he
will have a definition that is in accordance with
everything we know, and with the added advantage
MATTER AND ITS PROPERTIES 5
that if there be anything else in the universe that
involves observable phenomena he will not need to
confuse it with the phenomena of gravitative matter.
This is the sense in which that term is used throughout
this book.
Matter presents itself to our senses in a scale of
magnitude from particles in the neighborhood of the
hundred-thousandth part of an inch in diameter, and
requiring the highest powers of the microscope to
see, to such huge masses as that of the earth, eight
thousand miles in diameter, the planet Jupiter, nearly
eighty thousand miles, and the sun, eight hundred
thousand miles in diameter, while some of the more
distant stars are probably ten times larger than the
sun. The large masses, however, are but collections of
smaller ones, each particle bringing its own properties
of whatever kinds they may be; and it does not appear
that new qualities are developed by simply changing
the distance between bodies. So the properties of
matter may be studied exhaustively without employing
specimens inconveniently large.
The thin stratum of gold spread upon cheap jewelry
has all the characteristics and qualities of any specimen
of gold however large; and a small test tube of
hydrogen will exhibit all the kinds of phenomena that
MATTER, ETHER, AND MOTION 6
any larger quantity would show. For such reasons the
study of the universe of matter can be carried on in
the laboratory. The universe may be in the crucible
one holds in the tongs; whatever difference there may
seem to be, it will really be one of bigness only.
In treatises on physics one will generally find the
properties of matter arranged in two divisions, called
essential properties and non-essential ones. Of the
former are (1) extension, or space occupying; (2) inertia,
or passiveness under conditions of rest or motion;
(3) impenetrability, or total and exclusive occupancy of
its own space; (4) elasticity, or ability to recover its
form after distortion, this, however, varying in degree
in different bodies; (5) attraction, of which there are
several varieties,—gravitation, acting at all distances;
chemism, acting at close distances and selective in its
operation, and apparently not existing at all between
some kinds of matter, as, for instance, between oxygen
and fluorine. Chemism is also capable of complete
neutralization, and is thus in marked contrast with
gravitative attraction, which is not affected in the
slightest degree discoverable by contiguity; and lastly,
cohesion, which is not apparent except bodies are in
contact, but is the agency that holds the particles of
bodies together so they form liquids and solids of any
and all sorts.
MATTER AND ITS PROPERTIES 7
The so-called non-essential properties are color,
hardness, malleability, ductility, and the like, which
vary very much in different substances. Among
the metals silver is white, copper is red, gold is
yellow. Diamond is the hardest substance known,
while graphite is one of the softest, though both are
composed of the same ultimate substance—carbon. Iron
is malleable, and may be forged into any shape. Gold
may be hammered out into leaves no more than one
three-hundred-thousandth of an inch thick, but zinc is
wholly unmanageable in that way. Platinum, one of
the heaviest metals we have, can be drawn out into
a wire finer than a spider’s web,—a single grain may
be drawn into a mile of wire; while bismuth, also a
metal, cannot be drawn at all.
There are other conditions of matter that offer
opportunities for convenient grouping sometimes, such
as the solid, the liquid, and the gaseous: the solid
being the one where the parts strongly cohere; the
liquid, where the parts have but slight cohesion; and
the gaseous, where the individual particles do not
cohere at all, but, being elastic, bump against each
other and rebound continually.
Farther on it will be shown how all substances may
assume either of these conditions, inasmuch as it is
temperature that determines whether a given substance
MATTER, ETHER, AND MOTION 8
be a solid, a liquid, or a gas.
Density signifies compactness of matter, or the
relative number of particles in a given unit volume. If
compression be applied to two cubic feet of common
air until it occupies but one cubic foot, there is twice
as much matter in that cubic foot as there was at the
outset, and we express that fact by saying that the
density is doubled. If twice the amount of matter is in
the unit space, evidently the weight of the matter in
that space must be twice what it was at first. So one
may measure the density of matter by the weight of
a unit volume of it compared with the weight of the
same volume of some other substance taken as unity.
Thus, if a cubic foot of water weighs 62.5 pounds, and
a cubic foot of rock weighs 155 pounds, the density
of the rock is 212
, which means that it is 21
2 times
heavier than water, and that the amount of matter in
the rock is 212
times greater than that of the water.
Such determinations have been made of all the different
materials that could be found, and extensive tables have
thus been constructed; but it is seen that the appeal is
to gravitation, and presumes that every particle obeys
that law, and that degrees of compactness of matter
do not affect the law. Such comparative tables, based
upon gravitation measure, are frequently called tables
of Specific Gravity, so that density and specific gravity
MATTER AND ITS PROPERTIES 9
mean substantially the same thing. The following
examples of the relative densities of bodies may be of
interest:—
Gold, 19 Diamond, 4 Alcohol, .8
Silver, 10.5 Common Stone, 2.5 Ether, 1.1
Copper, 8.8 Wood, .8 Water, 1
Iron, 7.8 Sulphuric Acid, 1.8 The Earth, 5.6
Such numbers are to be understood as signifying that
if a given volume of water weighs one pound, an
equal volume of gold weighs nineteen pounds, an equal
volume of iron seven and eight-tenths pounds, and so
on.
Sometimes, however, it is convenient to choose for
a standard of density some body, a small unit volume
of which is much lighter than water, such as air, or
more frequently hydrogen gas, a hundred cubic inches
of which weigh 2.2 grains. In the metric system, a litre,
which is nearly two pints is the standard of volume;
and a litre of hydrogen weighs .0896 of a gram.
In chemical work this is the common standard for
gases; while for solids and liquids a cubic centimetre
of water is taken, which weighs one gram.
MATTER, ETHER, AND MOTION 10
DIVISIBILITY OF MATTER.
Particles of matter as small as the hundred-thousandth
of an inch may be seen with a good microscope as
the smallest visible thing, but there is no reason for
thinking that such a degree of fineness is any approach
to the ultimate fineness of the parts into which it is
possible to divide matter. For a long time philosophers
have considered whether or not there could, in the
nature of things, be an actual limit to the divisibility
of matter, so that the smallest fragment could not be
again divided into two or more parts by the application
of appropriate means, thus making matter infinitely
divisible, at any rate ideally.
In Mr. Spencer’s “First Principles” this subject is
considered at length, and the conclusion reached that it
is impossible to conceive the existence of real atoms—
bodies that cannot be divided into halves; nevertheless,
we shall see presently that it is possible to conceive
precisely that thing. It will be best here to note how
far division has been carried and the means employed
to effect it.
If a bit of phosphorus be put into a solution of gold,
the gold will be set free in such a finely divided state
that the particles remain suspended in the solution,
giving to it a blue, green, or ruby color, depending
MATTER AND ITS PROPERTIES 11
upon the degree of fineness into which it has been
broken up. Faraday estimated that the particles of
gold in the ruby-colored liquid did not exceed the
five-hundred thousandth part of the volume of the
liquid. One-eighth of a grain of indigo dissolved in
sulphuric acid will give a distinctly blue color to two
and a half gallons of water, which would be about the
millionth part of a grain to a drop of the water.
A grain of musk will keep a room scented for many
years. During the whole of the time it must be slowly
evaporating, giving out its particles to the currents of
air to be wafted presently out of doors; yet in all this
time the musk seems to lose but little in weight.
The acute sense of smell of the dog is well known;
for he can detect the track of his master long after the
tracks have been made, which shows that some slight
characteristic matter is left at each footfall.
A spider’s web is sometimes so delicate that an
ounce of it would reach three thousand miles, or from
New York to London. No one would think it likely
that such a web would be made up of a single row of
atoms, like a string of beads; for it would not seem
probable that such a string could have such a degree
of cohesion as spiders’ webs are known to possess.
Chemists have concluded from their experience with
matter in its various forms and conditions that it is
MATTER, ETHER, AND MOTION 12
really reducible to ultimate particles which have never
broken up, no matter what conditions they have been
subject to; and these ultimate particles are called atoms.
The term is not now understood to signify what is
implied in its derivation, as something that cannot be
divided, only something that has not yet been broken up
into smaller parts. Thus hydrogen, oxygen, iron, silver,
are reducible to such ultimate atoms; and there are
now known about seventy different kinds of atoms, and
these are often spoken of as the elements. Though they
are excessively minute when compared with ordinary
objects of sight, yet they have a real magnitude which
the physicist has measured in several different ways.
Most of these methods are complicated, and, in order to
be understood, require a pretty thorough knowledge of
molecular physics; but the following one may probably
serve to give one an idea of the degree of smallness
which atoms must have.
When a soap-bubble is blown, the material of the
film slides down the sides, making the bubble thinnest
on top. When a certain degree of thinness has been
reached at the top, colors begin to appear in concentric
rings, and these colors appear to move towards the
equatorial regions, new rings being formed at the top
as fast as room is made for them by the displacement
of the earlier ones. These colors always appear in
MATTER AND ITS PROPERTIES 13
the same order as they are in the rainbow, namely,
beginning with the red and ending with the violet,
then another set with the same order, until there have
been ten or more such sets of rainbow tints. They are
explained as being due to what is called interference
in the light waves that fall upon the film. Light is
reflected more or less from every surface it reaches.
Some light is reflected from the first or outer surface
of the film; some goes through the film to the inner
surface, and is there reflected back to the outer surface,
and then takes the direction that the light has which
is reflected from the first surface, so that the light
that reaches the eye from a point on a bubble comes
from both outer and inner surfaces. That coming from
the inner surface has had to travel farther than that
coming from the outer surface by a distance of twice
the thickness of the film. As light consists of waves,
if one set of waves all of a length be made to move
in the same direction as another set having the same
length, their crests may coincide and produce a single
higher wave; or the crest of one may be behind the
crest of the other at any distance up to one-half the
length of the wave itself, in which case the crest of
one will coincide with the trough of the other, and
the two waves will cancel each other, and this process
is called interference. Now, in the case of the bubble,
MATTER, ETHER, AND MOTION 14
when the thickness is such that the distance through
the film and back again is such as to equal half a wave
length of a given kind of light, that particular wave
is extinguished; and when one of the constituents of
white light is wanting, that which is left is seen as
colored light, and the color seen must depend upon
the kind of color that has been cancelled. Red light has
the longest wave length, about one forty-thousandth
of an inch, and violet, the shortest of the waves we
see, about one sixty-thousandth of an inch; and when
these colors are seen upon the bubble we are assured
that the interferences are produced by thicknesses due
to fractional parts of such wave lengths. As the ray
must go through the thickness twice in order to fall
behind one-half of a wave, it follows that the thickness
of the film where the last set of colors appear can be
no more than one-fourth of the wave length of the
shortest wave we can see, that is,
1
4 
1
60, 000
= 1
240, 000
of an inch.
When a bubble has reached this degree of thinness, so
that no more colors are to be seen, a rather remarkable
physical effect may be noticed. The film becomes almost
jet black, with a jagged edge well defined between
it and the brighter colored rings where the adjacent
MATTER AND ITS PROPERTIES 15
tint is purplish. The thickness of the film has fallen
suddenly off here to about one-fortieth of the thickness
it has where the tint is visible, and the bubble breaks
in a second or two after this black patch appears; that
is, when its thinness at any point becomes as small as
1
240, 000 
1
40
= 1
9, 600000
of an inch.
As the bubble, however, does persist for a short time,
and the thin film has cohesion enough to enable it
to support the weight of the bubble, it seems highly
probable, but is not absolutely certain, that it must
be more than one molecule of water thick at the
thinnest place, which is, as shown, only about the one
ten-millionth of an inch thick. If one thinks it probable
that it be, say five molecules thick in order to have
the degree of cohesion it shows, then the size of such
molecule of water out of which the bubble is made
can be but the one-fifth of the above small fraction,
which gives about the one fifty-millionth part of an
inch as the diameter of a molecule of water.
But a molecule is not the same thing as an atom:
it is made up of atoms, chemically combined, and is
defined generally as being the smallest fragment of a
compound body that can exist and possess the physical
characteristics that belong to such body. Thus, a drop
MATTER, ETHER, AND MOTION 16
of water possesses all the characteristics of any larger
quantity of it, and a drop may be divided into smaller
and smaller globules, perhaps a million of them, each
one being visible with a good microscope; but if the
division be carried to a higher degree, as it can be
by various methods, chemical, electrical, and thermal,
the qualities of water disappear, and two different
substances, oxygen and hydrogen, are left, both gaseous
under all ordinary conditions, and neither of them
exhibiting any properties like water or from which any
of the properties of water might be inferred. It may be
well to remark here that this is only one illustration
out of multitudes that might be named throughout the
whole domain of physical science, that the properties
of things under common observation are not simply
the properties that belong to the elements out of which
the things are built up; such properties being the result
of collocation rather than inherent qualities.
The molecule of water is then a compound thing,
and is made up of three atoms,—two of hydrogen and
one of oxygen,—and therefore the actual size of an
atom of hydrogen must be less than that represented
by the above small fraction of an inch. Evidently
a thing made up of three individual parts and two
dissimilar substances cannot be spherical, and it will
be well to bear this in mind in thinking of molecular
MATTER AND ITS PROPERTIES 17
forms. One may imagine the atoms themselves to be
spheres, or cubes, or tetrahedra, or rings, or disks, or
any other forms he likes, for the purpose of getting
some sort of a mental picture of what a molecule might
look like if it could be seen with a microscope; and
it is probable that very many persons have hoped or
thought that the microscope would sometime be so far
perfected as to enable one to actually look upon the
molecules of matter and perhaps upon their individual
atoms. Let us therefore consider the problem of how
much more powerful a microscope must need to be
than any we possess to-day, in order that one should
see a molecule! We will assume atoms to be about
the one fifty-millionth of an inch in diameter, and that
when combined into molecules they are geometrically
arranged so that the diameter of a molecule made up
of a large number of atoms is proportional to the cube
root of the number of atoms, as is the case with larger
bodies, say a box of bullets.
A molecule of water contains three atoms, a molecule
of alum about one hundred, while, according to Mulder,
a molecule of albumen contains nearly a thousand
atoms. Then, according to the assumption, the molecule
of alum would have a diameter equal to
3p100
50, 000000
= 1
10, 776000
of an inch,
MATTER, ETHER, AND MOTION 18
and that of albumen would be equal to
3p1, 000
50, 000000
= 1
5, 000000
of an inch.
Now, the best microscopes made to-day will enable
one to see as barely visible a point the one hundredthousandth
of an inch, so that such a microscope
would need to be as much more powerful than it
now is as one hundred thousand is contained in
five millions, that is, fifty times, in order to see the
albumen molecule, and for the alum molecule as many
times as one hundred thousand is contained in ten
million seven hundred thousand, that is, one hundred
and seven times. Now, one who is familiar with
the microscope would probably admit that one might
be made through improved methods of making and
working glass hereafter to be discovered, two or three,
or even ten times better than the best we have now; but
the idea of one being made fifty or one hundred times
more powerful than we have to-day, I do not think
would be allowed to have any degree of probability.
The case may be illustrated as follows: Suppose in the
days of the stage-coach some one had imagined that by
some improvement in methods of travelling one might
some day travel one hundred times faster than the
stage-coach could then go. Twelve miles an hour was
MATTER AND ITS PROPERTIES 19
not an uncommon rate then; but one hundred times
that would be twelve hundred miles an hour, and that
is sixteen times faster than the best we can now do, and
about twenty-five times faster than express-trains now
go. As a matter of fact, we travel about three or four
times faster than the best stage-coaches did, and, on a
spurt, may go six or eight times faster. The powers of
the microscope have not been doubled within the last
fifty years, and I suppose more time and ingenuity
have been given to the problem of improving it than
will ever be given to it in the same interval again.
There is another and still more serious reason
why there is no probability that any one will ever
see a molecule, even though the microscope had the
magnifying power sufficient to reveal it; namely, the
motions that molecules are known to have would
absolutely prevent one from being seen. A free
molecule of hydrogen has a velocity of motion at
ordinary temperatures of upwards of a mile in a
second, and its direction of motion is changed millions
of times in a second. A microscope magnifies the
movements of an object as much as it does the object
itself. An object in the field of a microscope that should
have a movement no greater than the hundredth of an
inch in a second could only be glimpsed, so there is
no possibility of one’s being able ever to see a free
MATTER, ETHER, AND MOTION 20
gaseous molecule. Supposing one should be seized and
held in the field, even then it is to be remembered
that it is in a state of vibration, changing its form
constantly on account of its temperature, so that its
wriggling would prevent any inspection.
Lastly, there is every reason to believe that the
molecules of all bodies are so perfectly transparent that
they can no more be seen than can the air, even if
there were no difficulty from their smallness and their
motions.
If the atoms of a single element like hydrogen are
so minute, so restless, and so transparent that no one
can hope to see them so as to make out their forms
and what gives them their characteristic properties,
what shall be said of the case of seventy or more
elements similarly minute and restless and transparent,
yet each one easily identified in several ways, physical
and chemical? Does it seem in any way probable
that such differences in properties as are exhibited by
gold, carbon, iron, and oxygen can be due simply to
differences in size or shape of the atom? Presumably
not; and the constitution of matter has therefore always
been a mystery to philosophers, for if one is to attempt
to philosophize upon the subject in accordance with
such other knowledge as we have, one would need
to conclude that if the different kinds of matter, the
MATTER AND ITS PROPERTIES 21
elements as we know them, were formed out of some
prior kind of substance, as bullets and marbles are
formed out of lead and clay, then there must be as
many different kinds of substances out of which the
different elementary atoms are formed as there are
different elements, which proposition does not seem to
have such a degree of probability that any one could
adopt it. If one sought for the explanation of the
different properties by assuming that all the different
kinds of elements were formed out of one and the
same fundamental substance, then it is equally difficult
to understand how mere differences in size and shape
could give such profound differences in quality as the
elements possess.
Then, again, it appears that the individual atoms
of each element are precisely alike. One atom of
hydrogen is precisely like every other atom, so far as
we have definite knowledge. Sir John Herschel likened
them to manufactured articles on account of their exact
similarity. A machine may turn out buttons or hooks
or wheels or coins so exactly like one another that no
one can tell them apart. It is really appalling to think
of the immense numbers of atoms of every one of these
seventy elements. It is a simple matter to calculate
how many atoms there must be in say a cubic inch.
It requires no other process than the application of
MATTER, ETHER, AND MOTION 22
the multiplication table. If the diameter of one be the
fifty-millionth of an inch, then fifty million in a row
would reach an inch, and a cubic inch would contain
the number represented by the cube of fifty millions,
which is
125000, 000000, 000000, 000000,
(125 followed by twenty-one ciphers) a number which
is more conveniently represented by 125  1021. The
utter impossibility of conceiving such a number will be
apparent if one would try to represent to himself what
the magnitude of only one million really is. Go out
on a clear but moonless night and the heavens appear
to be filled with stars. Count all that can be seen in
a certain portion of the sky, say one-tenth, as nearly
as can be estimated, and then determine the number
in the sky that are in sight by multiplication. It will
be discovered that only about two thousand can be
seen in the whole sky. If one million stars were to be
thus visible, it would require five hundred firmaments
as large and as well filled as the one looked at to
contain them. With the largest telescopes less than a
hundred millions of stars are visible; but what shall
one say when he learns that beyond a peradventure
the number of atoms in a single cubic inch of matter
of any sort is more than a million of millions times
MATTER AND ITS PROPERTIES 23
all the stars in all the heavens visible in the largest
telescope.
If one fancies that kind of work he may compute
the number of atoms that make up the world. Of
course it will make the number much larger; but when
written out not so much longer as one might think,
for when it is multiplied a million times it will add
but six ciphers to it. Some mathematicians have been
to the pains to compute the number of atoms there
are in the visible universe, or, rather, the number that
cannot be exceeded; for if the number stated above
fills a cubic inch, if one knows the diameter of the
visible universe, the space it occupies can readily be
known in cubic miles and cubic inches, and if all this
space was filled with atoms one could know and write
down their number. Astronomers tell us that some
stars are so distant that their light requires as long as
five thousand years to reach us, although the velocity
of light is as great as 186, 000 miles in a second, and
this distance is to be measured in every direction about
us. If this be our visible universe, then the maximum
number of atoms in it are calculable, and are stated to
be represented by the figure 6 followed by ninety-one
ciphers, or, as it is usually written,
6  1091.
MATTER, ETHER, AND MOTION 24
If we return to microscopic dimensions, and compute
the number of atoms, there will be in the smallest
amount of matter that can be seen with the highest
powers of the microscope, the one hundred-thousandth
of an inch, it will be seen that five hundred atoms
in a row would just reach the distance; and the cube
of 500 is 125, 000, 000, that could be contained in a
space so small as to appear like a vanishing-point
and the structure or details be utterly invisible. We
have read of spirits that could dance upon the point
of a needle, but the point of a needle would be a
huge platform when compared with this last visible
point with the microscope; and the spirit that should
dance upon it might be a million times bigger than
an atom of matter, and not be in danger from vertigo.
One may be astonished at the amount of intelligence
associated with the minute brain structure of some of
the smaller forms of animal life—say the ants; but
from the above it will be seen that so far as such
intelligence is associated with atomic and molecular
brain structure, the size of the brain in the smallest
ant, though measured in thousandth of an inch, is
sufficiently large to involve billions of atoms, and the
permutations possible are almost unlimited. The same
idea is applicable to the brain of man, and seems to
indicate that such differences in quality of mind as we
MATTER AND ITS PROPERTIES 25
see are not so much due to the differences in amount
of brain, measured in cubic inches, as in atomic and
molecular structure.
The work of physicists and chemists, carried on
for many years, has convinced them that none of
the processes to which matter has been subjected has
affected its quantity in the slightest degree. A definite
quantity of hydrogen, or, what is precisely the same
thing, a definite number of hydrogen atoms, may
be subject to any conditions of temperature, may be
made to combine with other elements successively,
forming with them solids or liquids or gases, and no
atom is destroyed nor its individual properties changed
in any degree. Neither has any phenomenon been
discovered indicating that new atoms of any kind are
ever produced by any physical or chemical changes
yet known. Time does not alter them. Elements that
have been imbedded in rocks from primeval times,
reckoned by millions of years, when liberated to-day
and tested, exhibit precisely the same characteristics
as those obtained from other sources and that have
been subject to many artificial conditions. Sometimes
a meteorite reaches the earth, a sample specimen from
distant space, having moved in some orbit about the
sun for millions of years. Thousands of such bodies
are in our possession, and they have been carefully
MATTER, ETHER, AND MOTION 26
analyzed, but no element unfamiliar to the chemist has
been found among them; and the iron, the nickel, the
carbon, the hydrogen, and all the rest of the elements
that compose them, behave in every particular like
those found on the earth.
So far as spectroscopic evidence goes, it testifies
to the presence of the same elements in the sun and
planets and comets; and it is as certain as anything
physical can be, that the expert chemist here would
be an equally expert chemist in the planet Mars, if
he could find a way to cross the immense space that
separates that star from us.
These facts and conclusions are frequently stated in
such a form as this, namely, that matter cannot be
created or annihilated. All that can fairly be meant by
such language is that under all the conditions at present
known, the quantity of matter remains constant; and
this proposition has a high degree of importance in
social affairs as well as in philosophy. If matter were
liable to change in its quantity or quality by being
subject to various physical conditions, all industries
involving commercial interests would be in an unstable
state. If the ton of iron ore should turn out, when
smelted, only fifty per cent of iron instead of sixty
per cent, as now,—the rest being either annihilated or
transformed into lead or gold, or something else,—the
MATTER AND ITS PROPERTIES 27
smelting company would soon go bankrupt, even if
gold were the product instead of iron, for if gold were
liable to be produced in that kind of a way, its value
would be next to nothing as a standard of value.
The old alchemists sought to transmute what they
called the baser elements into gold. It is safe to say,
if it were physically possible to do it and some one
should discover the art, and it were an economical
process, commercial disaster such as the world has
never known would follow its announcement. It would
be as if the volcanoes of the world should suddenly
begin to eject gold in the place of lava.
Stability of physical properties is as essential for
the stability of society as the regular recurrence of
day and night; and philosophy would be impossible if
fundamental data were not in every way immutable.
These physical principles lead to some curious and
most interesting conclusions with regard to the great
difference there is between bodies of matter of any and
all kinds that are familiar to our senses and the atoms
out of which these larger bodies are composed. In every
case, where there is a difference in movement between
two of these larger bodies made up of atoms, there is
what we call friction, which invariably results in wearing
away some of the material of both. It is the result of
mechanical friction, to tear away some of the surface
MATTER, ETHER, AND MOTION 28
molecules of the two bodies. Bodies in use much,
and therefore most subject to friction, become worn
out. Our clothing is a familiar example; the journals
of machinery, the tires of wheels, the sharpening of
tools, the polishing of gems, the weathering of wood
and stone,—all show that attrition removes some of the
surface materials of such bodies, but there is nothing
to indicate that attrition among atoms or molecules
ever removes any of their material. It appears as if
one might affirm in the strongest way that the atoms
of matter never wear out, are not subject to such
friction and the consequent destruction as comes to all
bodies made up of them. The molecules of oxygen
and nitrogen that constitute the air about us have been
bumping and brushing against each other millions of
times a second for millions of years probably, and
would have been worn out or reduced, as the rocks
upon the seashore have been beaten and ground into
sand, if they had been subject to friction. So one may
be led to the conclusion that whatever else may decay
atoms do not, but remain as types of permanency
through all imaginable changes—permanent bodies in
form and in all physical qualities, and permanent in
time, capable, apparently, of enduring through infinite
time. Presenting no evidences of growth or decay,
they are in strong contrast with such bodies of visible
MATTER AND ITS PROPERTIES 29
magnitude as our senses directly perceive. Valleys are
lifted up and become mountain-tops; mountains wear
away and are washed into the ocean; the beds of the
ocean sink and rise; and the boundaries of continents
may be worn and washed away through the incessant
beatings of waves against their coasts. Wear and tear go
on in all inanimate nature unceasingly, so that it is only
a question of time when everything we see upon the
earth will have changed beyond identification. The sun
is shrinking, and must some time cease to shine. The
stars, too, are changing likewise, because they shine,
and their places in the firmament will be vacant. All
living things grow because of change, and decay because
of more rapid change, and there appears to be nothing
stable but atoms. If it could be shown that life itself
and the mind of man were in some way associated with
atoms of some sort, as inherent properties, the hopes
and longings cherished by mankind for continuous
existence beyond the short term of three score years
and ten would give way to convictions as strong as
one has in any physical phenomenon whatever; the
evidence would be demonstrative in the same sense
as it is for the existence of atoms and their physical
qualities.
MATTER, ETHER, AND MOTION 30
CHAPTER II
The Ether
An incandescent electric lamp consists of a fine
thread of carbon fixed in a glass bulb from which the
air has been exhausted. When a proper current of
electricity is permitted to traverse the carbon filament,
it becomes white-hot and gives out light like any other
hot body. Other luminous bodies are in the air, and
one might infer that the light was transmitted from
the heated body to the eye by the material of the air
itself. The light in the vacuum shows that this is not
necessarily so, for the more perfect the vacuum is made
the more freely does the light from the filament reach
the glass bulb that encloses it. One is therefore led to
infer that matter is not the agent that transmits light.
The light of the sun reaches us after travelling through
ninety-three millions of miles of space in about eight
minutes. There are the best of reasons for believing
that the atmosphere of the earth does not reach at
most more than two hundred miles upwards from the
surface, and its density at the height of only one
hundred miles is such that there would be only about
THE ETHER 31
one molecule to the cubic foot.
It is not unlikely that there are free-roving molecules
in space, as there are meteors in all directions about
us, varying in size from fractions of a grain to masses
weighing some tons, but the distance apart of these
bodies is so great on the average that they cannot be
considered as either help or hindrance to the passage
of the light of either sun or stars. It is known with
certainty that what we call the light from shining
bodies is a kind of wave motion. The phenomena of
interference, which can be brought about in several
different ways, and which was referred to in the first
chapter when speaking of the colors of soap-bubbles,
show this. It is possible to annihilate two rays of
light by making one of them to follow the other in a
certain way; and one cannot conceive that two particles
of matter of any sort could annihilate each other by
simply changing their positions, but this is precisely
what happens in light.
Wave motions of all kinds can cancel similar wave
motions; for the wave consists of periodic movements,
a crest and a trough, and when the crest and trough
of one wave are superposed upon the trough and crest
of another similar one, the result is the destruction
of both waves. The lengths of these waves have been
measured by a great many persons in various parts of
MATTER, ETHER, AND MOTION 32
the world, and they all concur that light can only be
explained by wave motions such as they measure.
If there be wave motions, evidently there must be
something moved. One cannot conceive of a wave
movement when there is nothing that can be moved;
so men have been compelled to believe that there is
some medium between the sun and the earth that is
capable of wave motion, and this medium they have
agreed to call the ether.
If one admits the existence of ether between the
sun and the earth as the agency for the transmission
of light, he will need to do much more than that. The
sun is but about ninety-three millions of miles distant,
but most of the planets are hundreds of millions and
some of them thousands of millions of miles from
us, and the light comes from them too; so the ether
must extend through the space occupied by the solar
system, the diameter of which is six thousand millions
of miles, and to cross this space light requires nine
hours, though going at the rate of one hundred and
eighty-six thousand miles per second.
Then there are the stars beyond our solar system,
the nearest one so distant as to require three and a
half years for the light to get to us at the same rate;
and some of these are so remote that thousands of
years are needed for their light to arrive. That light
THE ETHER 33
we see from them to-day left them before America was
discovered, before Jesus was born, before the pyramids
were built, and for all we should be able to see they
might have ceased to exist long ago, though their light
continues to shine. So the ether must extend to those
most distant stars we can see, and that, too, in every
direction. There is no exaggeration in the statement
that our visible universe is so great that light requires
ten thousand years to cross its diameter. There is no
reason, either, for setting that as a boundary to its
magnitude; but wherever light comes from to us, there
must this medium, the ether, be.
But there are other and just as good reasons for
thinking there must be some medium between bodies,
even when all atoms and molecules have been removed.
For instance, everybody knows that one magnet affects
another at a distance from it, and there is no kind of
substance known that will prevent such action when
interposed between them.
If one of these magnets be placed in the most
perfect vacuum that can be made, it still acts as it
would in the air, only with still greater freedom. One
cannot believe that one body can thus act upon another
body without some kind of a medium between them.
Is it not absurd to think otherwise? One may, if there
appears to him to be a good reason, suppose that
MATTER, ETHER, AND MOTION 34
there is a magnetic medium or ether different from
that one employed in the transmission of light; but
there is a similar need for imagining one for the effects
produced by electrified bodies upon other bodies in
their neighborhood. An electrified glass rod will attract
a pith ball or anything else just as well in a vacuum as
out of it; and it is certain that electrical attraction and
magnetic attraction are not identical, for an electrified
body will attract one kind of thing as well as another,
while a magnet is selective in its effects, and affects
iron chiefly. Hence, if each different effect in a vacuum
is to be attributed to some different kind of medium,
there would need to be an electric ether in addition to
the other two.
Then there is gravitative attraction, which has before
been mentioned. If it is not rational to think that one
body can act upon another body not in contact with
it and without some medium between them, then one
is bound to admit that the gravitative effects observed,
say between the moon and the earth, the sun and the
earth, and in every other case, are due to the action
of some medium between them. Neither is it at all
needful to be able to explain how the medium acts
thus and thus, or even to imagine how it might, in
order to firmly believe that there must be one.
Here are four cases of apparent action at a distance
THE ETHER 35
of one body upon another, requiring some sort of
an intermediate agency; and, unless there be some
good reason for thinking there are several such media
occupying the same space apparently, it is much more
philosophical to believe it likely that one medium exists
capable of transmitting effects of the different kinds;
and especially will this appear to be truer if it is
known, as it is known, that the magnetic and electric
effects are transmitted with the same velocity as is the
light. So that physicists to-day quite concur in the
belief that what was called at first the luminiferous
ether, on account of its function in transmitting light,
is the same medium that is concerned in the other
phenomena of magnetism, electricity, and gravitation.
It is likewise true that there are some physicists
who hold rather lightly upon this belief, taking it as a
convenient working hypothesis, and who would seem
to be ready in a minute to surrender the idea, unless
it had been demonstrated in the same way as the
existence of matter and of motion has been. But this
is not the attitude of philosophic minds.
Sir Isaac Newton deduced from the observed motions
of the heavenly bodies the fact that they attract each
other according to the law now known as the law of
gravitation, but he says nothing about how bodies can
affect each other. That is, in his “Principia” he does
MATTER, ETHER, AND MOTION 36
not attempt to explain gravitation. He explicitly does
say, however, that he has not employed hypotheses in
his work, yet we know from other of his writings that
the idea of a medium was constantly in his mind. His
“Principia” closes thus:—
“And now we might add something concerning a most
subtle spirit which pervades and lies hid in all gross bodies;
by the force and action of which spirit the particles of
bodies mutually attract one another at near distances and
cohere if contiguous; and electric bodies operate to greater
distances as well repelling as attracting the neighboring
corpuscles, and light is emitted, reflected, inflected, and
heats bodies; and all sensation is excited, and the members
of animal bodies move at the command of the will, namely,
by the vibrations of this spirit mutually propagated along
the solid filaments of the nerves from the outward organs
of sense to the brain, and from the brain to the muscles.
But these things cannot be explained in few words, nor are
we furnished with that sufficiency of experiments which is
required to an accurate determination and demonstration of
the laws by which this electric and elastic spirit operates.”
This shows plainly enough that he believed that
some medium, different from matter, was essential for
a mechanical conception of the phenomena he alluded
to. In a letter to Bentley he states his philosophical
judgment upon the subject in still stronger terms, and
it shows, too, the sense in which he is to be understood
when he says: “I frame no hypotheses”—which has
frequently been repeated to adventurous hypothecators
THE ETHER 37
as the example of the model scientific man. Hear him!
“It is inconceivable that inanimate brute matter should,
without the mediation of something else which is not
material, operate upon and affect other matter without
mutual contact, as it must do if gravitation in the sense
of Epicurus be essential and inherent in it. . . . That gravity
should be innate, inherent, and essential to matter so that
one body can act upon another at a distance through a
vacuum, without the mediation of anything else, by and
through which their action and force may be conveyed from
one to another, is to me so great an absurdity that I believe
no man who has in philosophical matters a competent
faculty of thinking can ever fall into it.”
Newton uses the word Spirit in the sense of a
substance entirely different from matter (see page 36).
Evidently Newton was so strong a believer in the
medium that we call the ether, though he could not
work out its mode of action, that he was ready to
discount the intelligence of any man who doubted it.1
If our knowledge of the existence of the ether is
1In 1708 Newton wrote thus: “Perhaps the whole frame of nature
may be nothing but various contextures of some certain etherial
spirits or vapors, condensed, as it were, by precipitation; and after
condensation wrought into various forms, at first by the immediate
hand of the Creator, and ever after by the power of nature.”
These with his other acute remarks concerning what we now call
the ether lead us to infer that his mechanical instincts were more to
be trusted in this field than his more labored efforts.
MATTER, ETHER, AND MOTION 38
not so positive as it is for matter, but is inferential,
it will be readily understood that the knowledge we
have of its properties cannot be very exhaustive. Some
have imagined that it was only a finer grained kind
of matter than that we know as the elements, and
that it must be made up of atoms, though almost
infinitesimal in size. Others think it cannot be granular
at all, but forms a continuous substance throughout
space. By “continuous” is meant that there are no
interstices in it: that it is constituted like a jelly, only
not made up of distinct parts or atoms, so there can
be no such thing as separating one part from another,
leaving a vacuous cavity or rent between them. One of
the reasons for thinking this to be the case is, that if it
were made up of finer atoms or of atoms at all, such
waves as those of light could not be transmitted by it.
Longitudinal waves, like those of sound in air, can be
transmitted by atomic or molecular structures but not
transverse waves, that is, such as are at right angles
to the direction of propagation. Some of these light
waves are as short as the hundred-thousandth of an
inch, and some are as long as the one two-thousandth
of an inch, and perhaps longer. Yet all of them are
transmitted with the same velocity in any and every
direction. From the fact that light travels with the same
velocity in every direction, it is inferred that the ether
THE ETHER 39
is not only homogeneous, but its properties are alike
in every direction. As light is transmitted in straight
lines, it seems to follow that there is no difference in
its quality in different parts of space.
That wave motions travel with such high velocity
in it has been interpreted as proving it to have a high
degree of elasticity, while the fact that it offers no
appreciable resistance to the movements of bodies of
matter in it is supposed to indicate that its density is
very small.
There are some, however, who think that such terms
as elasticity and density are not appropriately applied
to the ether. These terms signify properties of atoms
and molecules. If density signifies compactness of
atoms, then the word could not apply to something not
composed of atoms. In like manner, if elasticity means
ability to recover form after deformation, then it is
not applicable to substances that cannot be deformed,
and it is customary to speak of the ether as being
incompressible. Still, it is certain that stresses may be
set up in it in various ways, and that these conditions
may be propagated, in certain cases in straight lines, in
other cases in curved lines, so whether the explanation
be forthcoming or not, there is no doubt about the
facts.
There is no evidence at all that the ether is subject
MATTER, ETHER, AND MOTION 40
to gravitative action, or that it offers any resistance
to a body moving in it. That is to say, it gives no
evidence of friction. Here is the earth rotating upon
its axis, and the velocity of rotation at the equator
is a thousand miles an hour, and if there were an
appreciable amount of friction the earth must slowly
be coming to rest like a top spun in the air. Yet
the astronomers tell us that the length of the day has
not changed so much as the hundredth of a second
within the last two thousand years. Again the earth
revolves in its orbit about the sun at the average rate
of nineteen miles a second, and if the ether through
which it moves offered any resistance to the motion,
the length of the year would be changed, but no such
change has happened in historic times. Again, such
bodies as comets move very much faster than the earth;
some have been known to have a velocity of three
hundred miles per second when near the sun, but the
comets complete their circuits and give no evidence of
slackened speed due to friction in space.
If, then, the ether fills all space, is not atomic in
structure, presents no friction to bodies moving through
it, and is not subject to the law of gravitation, it does
not seem proper to call it matter. One might speak
of it as a substance if he wants another word than
its specific name for it. As for myself, I make a
THE ETHER 41
sharp distinction between the ether and matter, and
feel somewhat confused to hear one speak of the ether
as matter.
Nearly thirty years ago Helmholtz investigated, in
a mathematical way, the properties of vortical motions,
and, among others, pointed out that if a vortical motion
was set up in a frictionless medium, the motion would
be permanent, and it could not be transformed. Sir
William Thomson at once imagined that if such motions
were set up in the ether, the persistence of their form
and the possibility of a variety of motions would
correspond very closely with the properties that the
atoms of matter are known to possess. Such vortical
motions as are here alluded to, all have seen, as they
are often formed by locomotives when about starting,
if the air be quiescent. Horizontal rings, three or four
feet in diameter, may be seen to rise wriggling into the
air sometimes to the height of several hundred feet.
They may be formed also by smokers by a vigorous
throat movement forcibly puffing the smoke from their
mouths, and they can be made artificially by providing
a box having a hole on one side an inch or two in
diameter and the side opposite covered with a piece
of cloth. A saucer containing strong ammonia water
and another with strong hydrochloric acid may be set
inside, and dense fumes will fill the box. If the cloth
MATTER, ETHER, AND MOTION 42
Diag. 1.
THE ETHER 43
be struck by the hand, a ring will issue from the hole,
and may go forward several feet, and its behavior may
be studied. Such as are formed in the air under such
conditions present so many interesting phenomena that
it is worth the while here to allude to them for the
sake of helping the mind to a clearer idea of how
some of the properties exhibited by matter may be
accounted for.1
1. The ring once formed consists of a definite amount
of the gaseous material of the air in a state of rotation,
Diag. 2.
and in its movements afterwards
retains the same material. It
is to be noted that the ring is
formed in the air, the white fumes
serving merely to make the ring
visible. The ring moves forward
in a straight line in the direction
it is started, just as if it were a
solid body. It may move very fast
too,—ten feet a second or more,
and reach the distant side of the
room, but it always moves of its own motion in a
direction perpendicular to the plane of the ring.
1The method of producing these vortex rings and their phenomena
are fully explained in “The Art of Projecting.” By Prof. A. E. Dolbear.
Illustrated. $2.00. Published by Lee and Shepard, Boston.
MATTER, ETHER, AND MOTION 44
2. It possesses momentum, and will push against
the object it hits.
3. If made to move rapidly adjacent to a surface
like a wall or table, it will move towards it as if it
were attracted by it, and generally will be broken up
by impact against it.
4. A light body, like a feather or thread, will
be apparently pushed out of the way in front of it,
and drawn towards it if behind it—phenomena like
attraction and repulsion.
5. If two such rings bump together at their edges,
each one will vibrate with well-marked nodes and
loops, showing that, as rings, they are elastic bodies,
and that their period of vibration depends upon the
rate of the rotation.
6. If two such rings be moving in the same line,
but the hindmost one swifter so as to overtake the
other, the foremost one enlarges its diameter while the
hinder one contracts until it can go through the former,
when each recovers its original dimensions.
7. If two meet in the same line, going in opposite
directions, the smaller one goes through the larger and
may be brought to a standstill in the air for a short
time until the other has got some inches away, when
it starts on in the same direction as before.
8. If two similar ones are formed at the same time,
THE ETHER 45
side by side, at a distance of an inch or two, they
always collide at once as if they had a mutual attraction.
The result of the collision may be the destruction of
one or both, or—
9. Each one may break at the point of impact,
and the opposite ends may weld together, forming a
single ring which will move on as if it had been singly
formed, or—
10. Instead of breaking they may rebound from
each other, but always at right angles to the plane in
which they were moving at first; that is to say, if they
were moving in a horizontal plane before impact, they
will rebound from each other in a vertical plane.
11. Three rings may in like manner be made to
join into one.
12. The material of the ring may often be seen
to be in rotation about the ring, while the ring, as a
whole, does not rotate at all, a rotary wave.
13. The parts of a ring may be in a state of
vibration in the ring without changing its circular form,
somewhat as if the ring were tubular and two bodies
should move up on opposite sides till they met and
rebounded to meet below, and so on.
All these, and some other just as curious phenomena,
may be observed in vortex rings, and may fairly be said
to be due to the properties of the rings themselves. For
MATTER, ETHER, AND MOTION 46
instance, the vibratory motions alluded to in the fifth
show that elasticity is a property of the ring, and that
the degree of elasticity does not depend upon what
the ring is made of, but upon the kind and degree of
motion that constitutes the ring. If such a ring could
be produced in material not subject to friction, none of
the motion could be dissipated, and we should have a
permanent structure, possessing several properties such
as definite dimensions, volume, elasticity, attraction,
and so on, all due to the shape and motions involved.
Imagine, then, that vortex rings were in some way
formed in the ether, constituted of ether. If the ether be,
as it is generally believed to be, frictionless, then such
a thing would persist indefinitely: it would have just
that quality of durability that atoms seem to possess.
It would possess physical attributes, form, magnitude,
density, energy, that is, it would not be inert. It would
be elastic, executing a definite number of vibrations
per second. This property of elasticity has generally
heretofore been assumed to be a peculiar endowment
of ordinary matter, and one was at liberty to imagine
some matter without it because not so made. This
view implies that elasticity is a necessary property of
vortex rings; for as the velocity of rotation is reduced,
so is the degree of elasticity, and if there was simply
a ring without being in rotation, it would have no
THE ETHER 47
elasticity at all, neither would it have any qualities
different from the medium it was imbedded in.
That such a quality as elasticity may be due solely to
motion, and varying with it, one may assure himself with
that piece of apparatus to be found in most collections in
schools known as Bonnenburger’s. It consists of a disk
of metal, mounted in gimbals so it can be set spinning
Diag. 3.—Bonnenburger’s
Apparatus.
in any plane. If this be set
spinning in a vertical plane it
becomes tolerably rigid in that
plane, and cannot be moved out
of it but by the employment of
quite a degree of pressure. If
the framework be quickly struck
by the finger while thus spinning,
the wheel will begin to rock back
and forth like the prong of a
tuning-fork, and the more rapid
the rotation the higher the rate of
vibration. When the velocity of
rotation becomes slowthe vibratory
motion may be as slow as once a second, and, of
course, when the ring is not revolving it will not
vibrate at all. Thus there is fairly good physical reason
for thinking that what we call elasticity in the atoms of
matter may be due simply to the motion they possess,
MATTER, ETHER, AND MOTION 48
and how that may be one can understand if atoms be
vortex rings.
One may properly ask how one vortex ring can
differ from another so there could be so many as
seventy or more different kinds of atoms. To this it
may be said that such rings may differ from each
other not only in size but in their rate of rotation: the
ring may be a thick one or a thin one, may rotate
relatively fast or slow, may contain a greater or less
amount of the ether. The word “mass” in physics
is used to denote a quantity of matter as measured
by its resistance to pressure tending to move it as a
whole. Thus if a pressure of one pound be applied
to two different bodies for say one second, and one
of them was moved an inch and the other but half
an inch when otherwise they were alike free to move,
we would say that one had twice the mass of the
other—its resistance to being moved was twice as great
as the other.
In the case of the Bonnenburger’s rotating disk, the
resistance to the pressure tending to move it depends
upon the rate of rotation, and a thin and swift moving
disk would offer much greater resistance than a much
larger one with a slower speed. So one might infer
that the difference in what is called mass among the
atoms of matter might be due simply to the different
THE ETHER 49
speeds with which the rings rotate, rather than in
the absolute volume of ether in the state of rotation.
There are other reasons than these for thinking that
motion is the chief characteristic of matter. Chemists
have discovered that both the chemical and physical
properties of all kinds of matter are functions of their
mass or relative atomic weights, and that they may be
arranged in a harmonic series. Harmonic relations may
imply either relations of position or of motion. But
the fundamental properties of matter do not change by
changing its position, and one is therefore led to the
conclusion that one must look to the various kinds of
motion involved among atoms for the explanation of
all their properties and all their phenomena.
There is another very important and peculiar property
possessed by vortex rings; viz., there cannot be such a
thing as half a ring or any fragment of one. Break such
a ring in two and there is not left the two halves; not
only is the ring broken, but each part at once vanishes
into the indistinguishable substance that composed it,
and all the properties that characterized it as a ring
have vanished with it.
This greatly aids one to understand that matter
may not be infinitely divisible. Over and over again
have philosophers asserted that it was impossible to
imagine an atom of matter so small that it could not
MATTER, ETHER, AND MOTION 50
in imagination be again broken into two or more parts.
A vortex ring, however, shows how the thing can be
done. If an atom be a ring, when it is disrupted it is
at once dissolved into ether, and that is the end of it.
There are no fragments of the ring.
One, however, must not infer from the above treatment
that it represents knowledge of a demonstrated kind,
for it does not. It was remarked in the first chapter
that atoms are too minute to be seen and studied as
one would study an animalcule or a blood corpuscle,
and one’s knowledge must be altogether inferential
concerning them; but what knowledge we do have,
and the inferences that may properly be drawn from it,
all tend to convince one that matter and the ether are
most intimately related to each other, and that some
such theory as the vortex ring theory of matter must
be true.
Now, it is either that theory or nothing. There is
no other one that has any degree of probability at all.
If what is presented herewith is not the precise truth
concerning a most difficult subject, it may have the merit
of helping one to conceive the possibilities there may
be of deducing qualities from motions, and rid him of
the idea that matter consists necessarily of some created
things that have no necessary relations to the rest of
the universe beyond the properties impressed by fiat.
THE ETHER 51
In the latter case one could never hope to understand
them, because there could be no necessary reason for
their being as they are, rather than some other way,
whereas, in the former case, the mechanical relations
can be understood, and there is left the possibility that
by and by, with more light and knowledge, one may
know the physical conditions under which matter itself
came into existence.
MATTER, ETHER, AND MOTION 52
CHAPTER III
Motion
Everybody has so clear a conception of motion that
there would not seem to be any difficulty in defining
it absolutely, but philosophers and others from remote
times till now have been perplexed by its problems.
How can Achilles ever overtake the tortoise, though he
runs ten times faster? How can the top of a cart-wheel
move faster than the bottom? If the sun cannot set
above the horizon and cannot set below it, how can
he set at all? In the last chapter some phenomena
were alluded to which were attributed to motions of
different kinds, and one must needs have a definite
notion of what he is talking about in order that his
words shall convey to himself, as well as others, the
information he would impart. Rest and motion are
contrasted conditions of bodies, so if a body is at rest
we say it is without motion, and vice versa. If two
persons sit side by side in a house they may be said
to be at rest, but if they sit side by side in a railroad
car they will be at rest relative to each other as they
were before, but may be in motion with reference to
MOTION 53
things outside the car. If, as a vessel sails past the
end of a wharf, a person on board would talk with a
person standing upon the wharf, he will walk so as to
keep opposite the man standing still, and the two will
be at rest in relation to each other, while one will be
in motion with reference to everything on board the
vessel. Thus it appears that rest and motion are relative
terms, and can only be understood to apply to the
relative continuous position of two bodies or objects.
Hence, if there were but one object in the universe
there could be no such thing as change of position,
for that implies another body with which position may
be compared at intervals. But such a single body
might have some internal motions by which there was
a relative change of position of its parts with reference
to themselves. For instance, a tuning-fork might be
at rest as a whole with reference to all other bodies,
yet its prongs might vibrate towards and away from
each other, the centre of mass or the centre of gravity
of the fork itself not moving in the slightest degree
either with reference to itself or anything outside itself.
Again, a body might spin like a top, and there would
be no change of position of the body as a whole with
reference to any other body, nor change of position of
the parts with reference to each other, yet there would
be a change of position of the parts with reference to
MATTER, ETHER, AND MOTION 54
all bodies outside itself. Hence, a brief definition of
motion is not so easy to give.
One might say that motion was the change of
position of a body with reference to other bodies, or
the change of position of the parts of a body with
reference to each other, or the change of position of
the parts of a body with reference to other bodies. But
these would not cover all possible cases. There need be
no trouble, however, in particular cases, because there
will always be data at hand to determine the character
and direction of the motion.
One may study the geometry of positions and
changing positions of mathematical points, and attend
only to rates and direction of motion of all sorts,
without considering the motions of bodies of real
magnitude possessing physical properties like matter.
The science that has to do with such ideal conditions is
called kinematics. Whenever the motions of matter are
considered, the science is called kinetics. Of course all
phenomena involve the motions of matter. Although
one sees a great variety of motions, a few examples of
particular sorts may be helpful in analyzing them.
1. The drifting of clouds, the flight of birds, of
arrows, of bullets, of meteors, the sailing of vessels, the
running of locomotives, are examples of one kind of
motion; namely, where the change of position is that
MOTION 55
of the body as a whole with reference to other bodies
external to it. The cloud may drift with the air, but with
reference to the surface of the earth it moves. Where a
body thus moves straight on continuously with reference
to other bodies, whether the distance moved be long
or short, the motion is called translatory or free-path
motion. The latter term is most frequently applied to
the movements of the molecules of a gas. In ordinary
air the distance apart of the molecules is on the average
about the one two-hundred-and-fifty-thousandth of an
inch, but the molecules themselves being only one
fifty-millionth of an inch in diameter, it will be seen
that they have a space to move in about two hundred
times their own diameter before coming in collision
with another one; and after collision their direction is
only changed when they go on to another collision,
and we say that their free path is on an average about
the two-hundred-and-fifty-thousandth of an inch. With
some modern air-pumps it is possible to reduce the
amount of air in a space so that the average free path
of a remaining molecule will be a foot or more; but
neither the size of the moving body, nor the distance
hundred times their own diameter before coming in
collision with another one; and after collision their
direction is only changed when they go on to another
collision, and we say that their free path is on an
MATTER, ETHER, AND MOTION 56
average about the two-hundred-and-fifty-thousandth of
an inch. With some modern air-pumps it is possible
to reduce the amount of air in a space so that the
average free path of a remaining molecule will be a
foot or more; but neither the size of the moving body,
nor the distance it moves, nor the velocity with which
it moves, makes any essential difference in the specific
kind of motion: so the movements of air particles
among themselves, of billiard-balls between impacts, of
a bullet on its way to the target, and of a planet or
comet in its orbit, are all examples of the same kind
of motion, namely, translational.
2. The swaying of the branches of trees when
moved by the wind, the swinging of the pendulums of
clocks, the movement of the piston in a steam-engine,
of the prongs of tuning-forks, the reeds and strings
in musical instruments, are examples of a different
kind of motion, inasmuch as the changes of position
relate to the body itself rather than to external bodies.
The tuning-fork is the type of them all, and together
they are called vibratory motions. Sometimes, when
the bodies that move thus are large and the motion
conspicuous, as, for example, in the pendulum of
the clock, and the steam-engine piston, the motion is
spoken of as oscillatory. In such cases, as in the former
one, it should be borne in mind that mere differences
MOTION 57
in the size of bodies, or of the rate of motion, does
not in any manner change the character of the motion,
so the name that is applicable to one will be equally
applicable to all. If one calls the movement of a
vibrating tuning-fork vibratory, the same term may be
applied to an atom if it goes through a like periodic
change of form, for that is the chief characteristic of
vibratory motion; and hereafter it will appear how
needful it is to bear this in mind, for what a given
amount of motion will do will be seen to depend
altogether upon the kind of motion.
3. The spinning-top, the balance-wheels of engines,
the wheels of machines of all kinds, the turning of
the earth, and each member of the solar system upon
its axis, are examples of another sort, where the
displacement is not, as in the last, between parts of
the same body, but a change in the relative position
of each part of a body to what is outside itself. The
pendulum of a clock swings to and fro, but its point
of suspension does not move; whereas every part of a
turning-wheel is presented to opposite parts of space
in the plane of its revolution. This motion is called
rotary, and just as in the other two cases, I wish to
emphasize the fact that the term is properly applicable
to masses of matter of all degrees of magnitude; so
an atom may spin on its axis as well as the earth
MATTER, ETHER, AND MOTION 58
or sun, and the phenomena it will be competent to
produce by such spinning will be very different from
that produced by its vibrations or free-path motions.
These three kinds are all of the primary ones: all
the others we see are made up of these or their
compounds. For instance, a compound of a free-path
motion with a vibratory motion will give a wave or
sinuous motion if the direction of the vibration be at
right angles to the free path. A combination of a
free-path with a rotary may give a spiral motion, as
illustrated by the movement of a screw when pushed
and turned into a piece of wood.
In a sewing-machine may be seen all of these kinds
of motion and some other compounds more complex
than the ones spoken of, but one may readily analyze
them into the three primary ones.
These forms of motion have been spoken of as if they
were peculiar to matter; but it ought not to be inferred
that motion is not attributable to the ether. Indeed, we
know that some sorts of motions are propagated in the
ether. For instance, what we call light is an example.
Its form is undulatory; and, as we have seen above,
an undulatory motion is a compound of a rectilinear
and a vibratory. A spiral movement in the ether is
also known, and it is sometimes called rotary-polarized
light: its motion is like that of a screw, and we know
MOTION 59
that such a motion is a compound of a rectilinear and
a rotary. Rotary motions in the ether are also known
as taking place in front of magnetic poles, and are the
results of the magnetism imparted to the iron or other
substance. I am not aware that any simple rectilinear
motion is known to occur in the ether: there may be,
and likely enough is, such.
For convenience, motions that are large enough to
be visible are called mechanical motions, while those too
minute to be seen are often called molecular or atomic.
Sometimes these molecular and atomic motions are
spoken of as if they were mysterious, and not to be
understood in the same sense as the larger ones that
are visible to us; but it is difficult to justify any such
distinction, and difficult to imagine that any kind of
a motion a large piece of matter may have, a small
particle or atom cannot have, and vice versa. It would
seem probable that whoever finds a difficulty in this
cannot have strong mechanical aptitudes, and is not
gifted with an adequate scientific imagination.
A free body of any kind and of any magnitude may
have any kind of a motion whatever, and may move in
any direction and with different velocities, but the term
velocity is used in different senses when applied to
different kinds of motion. Thus the velocity of an atom
in its free path, of a musket-bullet, of sound-waves, is
MATTER, ETHER, AND MOTION 60
measured in feet per second. The velocity of vibrating
bodies is indicated by the number of vibrations they
make per second. A tuning-fork making two hundred
and fifty-six vibrations in a second is said to have that
rate of vibration, whether the actual distance moved be
one distance or another, which, of course, will depend
upon the amplitude of each individual swing; while
rotational velocity is generally specified by giving the
number of rotations per second, or per minute, or some
other unit interval of time. A top may spin a hundred
times a second, a balance-wheel of a steam-engine turn
four times, while the earth makes one revolution in
a day of twenty-four hours. The range in velocities
of these different kinds that have been measured is
very great indeed. In free-path or translational motion,
there may be the snail’s pace, perhaps less than an
inch a minute, the pace of a man walking say three
miles an hour, which is at the rate of eighty-eight
feet per minute. A race-horse may trot a mile in
two minutes and ten seconds, which is forty feet per
second. A steam-locomotive may run seventy miles an
hour, which is nearly one hundred feet per second. A
rifle-bullet may go a thousand feet, and a cannon-ball
two thousand feet in a second. The earth in its orbital
motion goes seventeen miles per second; meteors come
to the earth, from space, sometimes having a velocity
MOTION 61
of fifty or more miles per second, while comets may
reach the velocity of nearly four hundred miles in the
same time when near the sun. These are the velocities
of bodies of visible magnitude, but some of the motions
of molecules are fairly comparable with some of these.
Thus a molecule of common air is moving in its free
path about sixteen hundred feet per second, while a
molecule of hydrogen, which is much lighter, goes
more than six-thousand feet—upwards of a mile—in
the same time. As remarked before, the free path
for air molecules having but about the two-hundredthousandth
part of an inch, it must change its direction
an enormous number of times in a second,—as many
times as one two-hundred-and-fifty-thousandth of an
inch is contained in sixteen hundred feet;
250, 000  12  1, 600 = 4800, 000000.
Four thousand eight hundred millions of times. How
one may assure himself that such a statement is not
fabulous will be pointed out farther on; so far one
needs only to trust the multiplication table.
For vibratory rates there are also enormous ranges:
there are the slow oscillatory movements of swinging
pendulums of various lengths, sometimes occupying
several seconds for the execution of one vibration;
piano-strings having a range from about forty per
MATTER, ETHER, AND MOTION 62
second to four thousand; the chirrup of crickets about
three thousand. Short whistles and steel rods have
been made that will make as many as twenty thousand
vibrations per second,—a rate much higher than can
be perceived by most persons, though occasionally
abnormal hearing in an individual enables him to hear
sounds to which ordinary ears are entirely deaf. When
the number of vibrations per second becomes so great
that they cannot be individually seen nor heard, one
must trust his judgment and the properties of matter
in determining whether there really are any still more
rapid. It has been found by experiment that the number
of vibrations a given body can make when it is struck
so as to produce a sound depends upon its shape, its
size, its density, and its degree of elasticity. If a steel
rod, having a given diameter and length, makes, when
struck, five hundred vibrations per second, another
similar one with but half the length will make twice
as many in the same time. If one were made of
something still more elastic than steel, and of the same
size, the vibratory rate would be higher still.
A steel tuning-fork three inches long may make
five hundred vibrations per second; if it were only the
one fifty-millionth of an inch long it would make not
less than 30000, 000000 vibrations per second; and if it
were made of a substance like ether it would make
MOTION 63
as many as 1000, 000000, 000000—a thousand million of
millions per second. As large as this number is, and as
improbable as it would seem to be, there is indubitable
evidence that the atoms of matter do actually make
such a number of vibrations per second.
If one knows the rate at which vibrations are
propagated in a medium and the wave length, one can
readily determine the number of vibrations the body
is making that sets up the waves. Thus, if the velocity
of sound in the air be 1100 feet per second, and the
length of one wave be 1 foot, then the body must
be making 1100
1
= 1100 vibrations per second: that is,
the velocity divided by the wave length will give the
number of vibrations.
The velocity of light is known to be 186000 miles
per second; the wave lengths of light are also known
with great precision, and are all only small fractions
of an inch. If they were only one inch long, their
number would be the number of inches there are in
186000 miles, or 12  5, 280  186000 = 11784, 960000 per
second. In reality they are only one forty-thousandth
or the one fifty-thousandth of that.
11784, 960000  50000 = 589, 248000, 000000,
nearly six hundred millions of millions per second. No
one can pretend to comprehend such a number; but
MATTER, ETHER, AND MOTION 64
in proportion as he understands the process and the
data by which such a result is reached, will he have
an abiding confidence that it is legitimate and that it
expresses the actual truth.
Sometimes it is convenient to know the actual space
that is moved over by a vibrating body in terms
of free-path or translatory motion, that is, how far
would the body move in the same time if, instead of
vibrating, it went on in a straight line. If the prong
of a tuning-fork moves through the one-hundredth of
an inch each swing, and vibrates one hundred times
in a second, obviously its rate of motion measured
that way would be only one inch, which would be
a relatively slow motion when compared with many
others. If the same computation be applied to atoms,
however, whose rate of vibration is so enormously
high, it leads to some very respectable translational
velocities. Thus, suppose the amplitude of vibration
of an atom of hydrogen be as great as one-half its
diameter, that is, one hundred-millionth of an inch, if
it vibrates five hundred millions of millions of times
per second, the actual space moved through will be
500, 000000, 000000
100, 000000
= 5, 000000 inches = 80 miles,
which is more than four times that of the earth in its
orbit. It does not appear probable, however, that the
MOTION 65
amplitude of motion is anywhere near as much as that
assumed, at any rate for ordinary temperatures; but
if it be only the one-hundredth of that amplitude the
velocity exceeds that which can artificially be given to
any visible object, as it will then be nearly a mile a
second.
Rotary speeds have wide ranges. The earth takes
twenty-four hours to make one revolution; the moon
about twenty-eight days, and the sun twenty-six, and
some others of the planets perhaps much longer than
that. Some astronomers have concluded from their
observations of the planets Venus and Mercury, that
their axial rotation corresponds with their time of
revolution about the sun, being 224 days for Venus,
and 88 for Mercury. Tops have been made to spin
eight hundred or a thousand times per second; and if
molecules ever rotate their rate has not been measured.
The velocity of rotation, when measured as a translation,
must evidently depend upon the diameter of the body
rotating. The diameter of the earth being nearly eight
thousand miles, a point on the equator moves twentyfive
thousand miles in twenty-four hours—something
over a thousand miles an hour, or about seventeen
miles a minute. A driving-wheel of a locomotive that
is six feet in diameter will advance nearly nineteen
feet every revolution. To have a speed of a mile a
MATTER, ETHER, AND MOTION 66
minute, which is 88 feet per second, it must turn round
88
19
= 4.6 times per second. A disk 4 inches in diameter,
spinning 800 revolutions per second, which was the
speed given by Foucault to one of his gyroscopes,
would advance, if allowed to roll, with the speed of
837 feet per second—nearly ten miles a minute.
There are some facts, and inferences we draw from
them, with regard to motion and the geometry of space
that it may be well to mention here. When we speak
of the velocity of a body at a given time we mean by
it that its rate is such that if continued for the whole
interval of the unit of time, whether it be a second, or
a minute, an hour, or any other, the body will move
through the whole specified distance. A body will
not need to go a mile in a minute in order to have
a velocity of a mile a minute. It may not move ten
feet, yet may have that or any higher velocity. This is
obvious enough of course. Every one trusts arithmetical
processes to lead him to correct results in velocities
and time and all such familiar matters. One will say
frequently, “It is six hours to New York” instead of,
“It is two hundred miles to New York,” and will not
be misunderstood. Some persons have computed how
long a time it would take to reach the sun if they were
to take an express-train running at the rate of fifty
MOTION 67
miles an hour, without stopping for food or fuel; and
they find it comes out nearly two hundred years,—a
time of transit equivalent to five generations of men. In
like manner, presuming one knows the distance to any
remote point in space, the time required to get there
at a given velocity one would call a simple problem
in arithmetic, and it is. But there is an assumption
one has to make which is rarely considered: that
is, the properties of space and of time are the same
everywhere, and that the geometry of the space in
which we live is a geometry that holds everywhere
and always: that its propositions are absolutely and
irrefragably true always and everywhere. We assume,
because we find them practically true on a small scale,
that they are equally true on the largest scale.
Within the past fifty years the great geometers have
made some very wonderful discoveries—one might say,
astounding discoveries; for they tell us that we do not
know that the sum of the interior angles of a plain
triangle is equal to a hundred and eighty degrees, that
we do not know it within ten degrees if the triangle
be a very large one, such as is formed by the spaces
between remote stars and the sun; furthermore, we are
assured that, for all we know, and therefore for all we
can reason from, space itself may be curved so that if
one were to start in what we call a straight line, in
MATTER, ETHER, AND MOTION 68
any direction, and travel in it on and on he would find
himself after a long time coming to his starting-point
from the opposite direction; that what one would see
if his sight were prolonged in any direction would be
the back of his own head much magnified. Methods
have been proposed for discovering if it be true or
not. Some folks have called this nonsense, and have
used descriptive adjectives to express their contempt
for it; but none of those who have spoken thus of the
new geometry are themselves mathematicians, and one
is therefore left with the fair inference that they did
not so well know of what they condemned as did the
mathematicians who reached the conclusion.1
Now, we all of us trust such mathematical processes
as we can ourselves handle, even when they lead us to
magnitudes and distances too great for comprehension.
All that one needs to know is, that the process is a
legitimate one and is correctly worked out. This new
geometry I have alluded to has been worked at by the
best mathematicians of all the civilized nations, and
they agree in the conclusions. They certainly would not
do so if there were the slightest apparent reason for
rejecting them; for national jealousies are too strong,
and a sense of the value of truth too great, to allow
1See Appendix.
MOTION 69
any such notions to gain currency anywhere if there
were any possibilities of breaking them down.
If the space we live in and the geometric relations are
only practically true upon a small scale; if we may have
a kind of space of four or more dimensions, whether
we now can conceive of it or not, then should one
understand that spaces and distances and velocities and
all computations formed upon them, though practically
true, for all of our experience must not be pushed
up into statements that shall embrace all things in the
heavens as well as on the earth. Perhaps even the
visible universe is not to be measured by our span,
much less things invisible in it and beyond it.
MATTER, ETHER, AND MOTION 70
CHAPTER IV
Energy
Whenever a body of matter having any motion
strikes another body, it always imparts some of its
motion to it, and the second body moves. The ability
one body has to move another one is sometimes
called its energy, and the amount of energy received
is proportional to the amount of similar energy the
first body possesses. A body at rest can impart no
motion to another one, so it appears that the energy
a body has depends upon its own amount of motion.
Neither can a body impart to another one more motion
than it possesses itself, and rarely or never can it
do so much as that. Inasmuch as every kind of
a phenomenon is the result of the transfer of some
kind of motion from one body to another, one may
rightly infer that to understand phenomena and their
relations, one must need to know, not only the kinds
of motion that are transferred, but must also know
their quantitative relations, and he must therefore have
some units and standards for comparison. This requires
some measure for the amount of matter involved, also
ENERGY 71
some measure for the motion it has. For the former
it is customary to employ a weight. A certain mass
of matter called a pound is adopted in England and
America. Exact duplicates of its standard weights are
made and preserved by each nation; so as weights
become worn by usage, they may be exactly replaced.
Any unit space may be adopted, as the foot, which
is common. If a pound has been raised a foot, a
certain amount of work has been done, which is called
a foot-pound, and it is important to keep in mind just
what it signifies. If ten pounds be raised one foot, or
if one pound be raised ten feet, the same amount of
work—ten foot-pounds—has been done; and with this
as a starting-point, it will be easy to see how energy
may be measured, for the measure of it will be the
amount of work, measured in foot-pounds, it can do.
It is found by experiment that if a body be left free to
fall in the air, it will fall sixteen feet in a second, and
its velocity at the end of the second will be thirty-two
feet. If a very elastic ball weighing a pound should
fall thus in the air upon an elastic pavement, it would
rebound nearly to the height of sixteen feet. If it
does not quite reach that height, it is because the air
retards it somewhat, and some of its motion has been
imparted to the pavement upon which it falls. Adding
those losses to the height it did rise, and it would
MATTER, ETHER, AND MOTION 72
make the sixteen feet. Now, to raise a pound sixteen
feet required sixteen foot-pounds of work; there must
therefore have been sixteen foot-pounds of energy at
the instant of impact. Its velocity was thirty-two feet
per second. Hence a body weighing one pound, having
a velocity of thirty-two feet in a second, is capable of
doing sixteen foot-pounds of work. It is found also
that if the same body falls for two seconds, it will
fall sixty-four feet, and its velocity at the end of the
second second will be sixty-four feet,—twice as great
as it was for the fall of one second; but the pound
weight in this case will rise under similar conditions to
the height of sixty-four feet, which is four times higher
than for thirty-two feet per second; so it is seen that
in this case, when the velocity is doubled, the power
of doing work, measured in foot-pounds, has been
increased four times, and this is generally expressed
by saying that the energy of a body is proportional to
the square of its velocity. The particular direction in
which a body moves has not been found to make any
difference in this regard, so the statement is a general
one. If a mass weighing two pounds were dropped, as
in the first instance, it would rise no higher than if it
weighed but one; but two pounds raised sixteen feet
would give thirty-two foot-pounds, so the work would
be proportional to the weight as well as to the square
ENERGY 73
of the velocity.
The amount of matter there is in, say, a pound
weight would be just the same in one place as in
another; but the attraction of the earth upon it depends
upon where it is. At the surface, where we measure
it, it has a certain value; but at the centre of the earth
it would weigh nothing. The farther it were removed
from the surface of the earth upwards, the less would
its weight be. At the height of a thousand miles it
would be but four-fifths of a pound; at a million miles
it would be but sixteen-millionths of a pound, or only
about the tenth of a grain.
For that reason it has become necessary to find
some measure for matter that shall be independent
of position, and this has been found by dividing the
weight of the body at a given place by the value of
gravity at that place, and calling the quotient the mass;
so if w represents the weight of a body at a given
place, and g the value of gravity at the same place,
that is, the velocity that gravity will give to a body in
one second if left free to fall, then w
g
= m, the mass.
The distance in feet that a body will fall in a second
is equal to the square of the velocity divided by twice
the value of gravity, or d, the distance, = v2
2g
; and
as the weight equals mg, the product of the two is
MATTER, ETHER, AND MOTION 74
mg 
v2
2g
= mv2
2
, one-half the product of the mass into
the square of the velocity will give the energy of a
body. But it is generally more convenient to use the
weight of the body instead of its mass. As m = w
g
,
let it be substituted for m in the expression of energy,
and we shall have wv2
2g
= pd (pressure in pounds into
distance in feet), or foot-pounds, a very convenient
expression to keep in mind if one has any problems
in motion and energy for solution.
An example will make plain the utility of this. A
body weighing ten pounds is moving with the velocity
of one hundred feet in a second; how much energy
has it? wv2
2g
= 10  1002
64
= 1562 foot-pounds; that is, it
has energy enough to raise 1562 pounds a foot high,
or ten pounds 156.2 feet high.
This is applicable to all bodies, big and little, whose
weight and velocity of translation are given.
When a person who weighs one hundred and fifty
pounds climbs a flight of stairs—say, to the height of
ten feet—he has done 150  10 = 1500 foot-pounds of
work. Whether he has gone up fast or slow makes
no difference in the amount of work done; it will
only make a difference in the rate of doing work.
ENERGY 75
Now, a horse-power is a rate of work, and is equal
to 550 foot-pounds a second; and hence if the above
individual climbs the stairs at the rate of four feet a
second, he will be doing 4 150 = 600 foot-pounds per
second, which is over a horse-power, and indicates the
probability that he would not climb so fast. If any one
thinks he can do it, it will be worth his while to try it.
Work can be measured on a horizontal as well as a
vertical plane. Suppose the horses on a horse-car pull
two hundred pounds, as indicated by a dynamometer,
and the car is moved five feet in a second: the
pull into the distance measures the work done; that
is, pd = 200  5 = 1000 foot-pounds, a little less than
two-horse power. These illustrations are given because
not every one has clear enough ideas concerning the
meaning of energy and work, much less the ability
to apply them to examples that may often come up.
When one sees the long trail of a meteor in the sky,
and remembers that its velocity may be as much as
twenty or more miles per second, he will now see that
it may have a good deal of energy, though its weight
be but a few grains.
The energy of a pound moving twenty miles a
second would equal
1  (20  5280)2
64
= 174, 240000 foot-pounds.
MATTER, ETHER, AND MOTION 76
A grain is one seven-thousandth of a pound, and its
energy would therefore be but the one seven-thousandth
of that quantity. 174, 240000
7000
= 24891, which is the number
of foot-pounds of work a meteor weighing one grain,
at that velocity, may have: enough to raise a ton twelve
feet high.
As a matter of fact, the great friction it is subject
to in its path through the air heats it shortly to
incandescence, and it is presently dissipated. If it were
not for the air, therefore, even if we could subsist
without it, mankind would be in constant danger from
the flying missiles; for though they would weigh but a
little, their velocity would enable them to do destructive
work upon everything they struck. As there are some
millions that come into the atmosphere every day, no
one could be safe from them in any place.
The energy of a workingman is measured in the same
way; namely, by the amount of work in foot-pounds
he can do.
One of the most direct ways of knowing this for an
individual is to ascertain the amount of earth or stones
he can load into a cart, or the bricks he can carry
up a ladder to the mason. Suppose he throws fifteen
shovelfuls per minute, each one holding ten pounds,
and each one is raised four feet high: then in a minute
ENERGY 77
he has done 15  10  4 = 600 foot-pounds of work, or
10 per second. This is rather a small quantity, only the
one fifty-fifth of what a horse-power would do, and
most men have been found able to do forty or fifty
foot-pounds per second; still, there is a great difference
in individuals in their working ability. Climbing, in
general, is hard work because it is continuous lifting
of one’s self. One who weighs one hundred and fifty
pounds, and climbs one hundred feet, has done 15000
foot-pounds of work; and if he has done it in a minute,
he has spent nearly half a horse-power, which is 33000
foot-pounds a minute.
Once more: a bird in flying has to do work; and
one may see how much is demanded of such birds as
geese, that make long voyages through the air in the
fall and spring,—sometimes for twelve hours or more
continuously. As work is measured by pressure into
distance, one may apply it thus. Geese are known
to fly at the rate of thirty miles per hour, which is
forty-four feet per second. In flying, of course, there
has to be a push forward by means of their wings,
not only to advance, but to maintain their elevation.
Supposing that a large bird flying at this rate should
have to exert a push of one pound continually: it
would be expending then forty-four foot-pounds per
second, nearly one-twelfth of a horsepower; and to
MATTER, ETHER, AND MOTION 78
maintain such a rate for twelve hours would imply
that it had a supply of energy to start with of
44  60  60  12 = 1, 900800 foot-pounds for one day’s
expenditure. This does not seem at all probable, and
one may therefore infer that the pressure exerted when
going at that rate is much less. If the pressure were
but one ounce instead of a pound, the rate of work
would be 44
16
= 2.75 foot-pounds per second, which is
much more likely; but this supposes the bird to have
a supply of energy of 1, 900800
2.75
= 700000 foot-pounds.
In the chapter on “Chemism,” the source of the
energy of animals will be more particularly treated.
So far the energy involved in translatory or freepath—
or, as it is more often called, mechanical—energy
has been considered; but vibratory motions of matter
involve energy also, and the same expression is
applicable as in the first case, wv2
2g
. Here the value of
the v, or the velocity, has to be determined by analyzing
the motion itself. This is not simply the number of
times the body vibrates, but also the extent of each
individual vibration,—that is to say, the amplitude of
vibration,—and the product of these two factors will
give the value of v needed. So if n be the number
of times the body vibrates a second, and a be the
ENERGY 79
amplitude of the individual vibrations, the true velocity
will be represented by an, and then the expression for
the energy will be
wa2n2
2g
.
For most bodies of visible magnitude the amplitude of
vibration is so small a quantity that for frequencies of
only a few hundred per second, the velocity, measured
as a translation, is small, and therefore the energy
is small, and there are few cases where it is very
important to take it into account.
Suppose a vibrating body has an amplitude of the
one-hundredth of an inch, and vibrates a hundred
times in a second: the total distance moved through
in a second would be but an inch, which would be
the value of v, so the amount of energy it had would
depend more largely upon the weight of the body. On
the other hand, if a body is so small that its rate of
vibration is exceedingly high, as was shown in the
case of atoms on page 63, there might be a relatively
large amount of energy involved. In the case refered
to, a velocity of eighty miles a second was computed,
on the supposition that the amplitude of vibration was
equal to one-half the diameter of the atom; and what
amount of energy is possessed by a body weighing
one grain was computed. The amount in an atom with
MATTER, ETHER, AND MOTION 80
that vibratory rate and amplitude would be calculated
by dividing the amount in the grain by the number of
atoms in a grain. Numerically it is a very, very small
quantity, and only becomes appreciable to any of our
senses when vast numbers of atoms act conjointly.
There are some cases where energy is apparently
expended when there is no apparent motion, as is the
case when a man holds up a weight. If the weight be
a heavy one, exhaustion will be the result as much as
if energy was spent in any other way. This muscular
work is called physiological work, and for a long time
it was not understood. It is now known, however,
that when a muscle is put in a state of tension, it is
in longitudinal vibration a great many times a second.
This may be perceived by putting the end of a finger
into the ear, pressing but gently, at the same time
squeezing with the rest of the hand as if grasping
something tightly; a low sound will be heard, made
by perhaps no more than thirty or forty vibrations per
second. The muscles in a state of tension produce
this. When one holds up a weight—say, a pail of
water—the muscles involved yield and contract rapidly,
so the weight is really raised in a vibratory way a
short distance, but a great many times in a second;
and the heavier the weight, the more the work done,
and this too is measured in the same way as other
ENERGY 81
more visible kinds. There is good reason for believing
that a book resting upon a table is supported by the
vibratory motions going on among the particles of the
table, and therefore energy is expended to do it, and
that this is supplied by the heat present in the body;
that is, the temperature of the table is a little different
from what it would be if it did not have any weight
to support.
Walking involves the expenditure of energy in the
same way. Each step requires the whole body to be
raised somewhat. Suppose it be only an inch. A person
weighing 150 pounds would, for each step, do 150
12
foot-pounds = 1212
. If he takes two steps per second,
then each minute he does 2121
2 60 = 1500 foot-pounds
of work. Thus one can see how physiological processes
are measurable in terms of mechanical units.
The energy of a rotating body is more complicated
than translational energy, because a part of the body
is at rest,—the axis; and the velocity of movement
at any point away from that is proportional to its
distance from it. In the case of the balance-wheels
of steam engines, where the most of the weight of
the wheel is in the rim, the velocity of the latter
would be equal to its circumference multiplied by the
number of turns per second or per minute. Thus if
MATTER, ETHER, AND MOTION 82
a fly-wheel, having nearly the whole of its weight in
the rim, weighs, say, a ton (2000 lbs.), is six feet in
diameter, and rotates four times a second, its velocity
will be 75.4 feet per second, and its energy will be
wv2
2g
= 2000  75.42
64
= 177661 foot-pounds, an amount of
energy which is stored up, and may be drawn upon
to prevent fluctuations in speed to which engines in
workshops are liable.
If a body having rectilinear motion be left to itself
in the air, it will speedily be brought to rest, for gravity
will bring it to the earth whether it be moving this way
or that. The air, too, will retard its motion, and would
ultimately bring it to rest if nothing else did, as it would
either of the other kinds of motion. If, however, one
could contrive to give to a body above the atmosphere
a sufficient velocity in a tangential direction, the body
would become a satellite, and revolve round the earth.
The curvature of the earth is about eight inches to
the mile, and such a body would then need to move
a mile in a horizontal direction in the same time it
falls eight inches in order that it should continue to
go about the earth. As it takes about two-tenths of
a second to fall this distance, its velocity would need
to be five miles a second to prevent it from falling to
the earth; this velocity would carry it quite round the
ENERGY 83
earth in a little less than an hour and a half.
Thus it is seen that, in order that matter should
possess energy, it must have motion of some kind;
indeed, that energy has two factors, mass and motion.
When either of these is zero, there is no energy. This is
a consideration of great importance both in a scientific
sense and a philosophical one. One may often hear it
said and read it in carefully written books that matter
and energy are the two realities or physical things in
the universe, and energy is spoken of as if it were an
entity, or something that might exist though there were
no substance to move. If energy be a product, and
motion be one of the factors, then in the absence of
this there is no energy. This perhaps will be seen still
clearer after considering what are called the laws of
motion, which were first formulated by Newton, and
which, in conjunction with the law of gravitation, were
the fundamental principles that enabled him to produce
the “Principia,” which is what to-day we would call a
treatise on mechanics.
Of course, the science of mechanics is applicable to
motions of matter of any magnitude and in any place;
and Newton chose to follow out his newly discovered
principles into astronomy to the largest extent, and
it remained for later generations to employ the same
principles in other directions, largely molecular and
MATTER, ETHER, AND MOTION 84
atomic.
The first law of motion is, that whether a body
be in a state of rest or of motion, it will remain
in that state of rest or motion until compelled by
the action of some other body upon it to change its
state. This is sometimes expressed by saying that all
matter has inertia, or an inability to move or change its
direction or velocity if it has motion. This appears to
be experimentally true of all bodies whose magnitude
and state we can see. But it may very well be doubted
if the ordinary conception of the inertness of matter
be true. Many of the facts of chemistry indicate that
matter in its atomic form is not altogether so helpless
as it has been supposed to be. A stone may lie in the
road for an indefinite time and no one would suspect
it possessed any energy to do anything, and so of any
other kind of matter. Here is a piece of charcoal. Has
it inertness in any extreme sense of that word? Here
is some sulphur and some nitrate of potash; they, too,
will lie as quiescent as the coal and as long. Pulverize
them and mix them together, and we have powder
the energy of which would wreck a building. The
products of the explosion are gaseous mostly, and the
carbon, the sulphur, and the nitrate of potash have
vanished as such, and have entered suddenly into new
combinations; they have developed also a large amount
ENERGY 85
of heat, while at the beginning their temperature was
that of other bodies around them. This source of
energy must have been resident in the atoms; and if
it is perceived that for a body to have energy it is
necessary for it to have motion of some sort, it will be
apparent that the material itself must have possessed
a large amount of motion, even when it appeared to
be at rest. If one thinks that the law of inertia might
still apply to atoms, and that they cannot individually
move except as they are acted upon by other atoms,
and even then only as much as by the measure of
the motion thus imparted, he had better figure out to
himself the energy of such explosions per molecule,
and see if anything initially done will account for it.
When the mechanism of a clock is running, the
motion may be traced to a falling weight, and the
work done is measured by the product of the weights
into the distance it falls as the clock runs down; but
in the case of the powder, though the amount of
energy developed by the explosion is definite, it is
not measured by the work done in pulverizing and
mixing and igniting it. The case is much more nearly
analogous to that of a sleeping man. While asleep
he would neither move nor stop moving unless some
other agency acted upon him, any more than would
a stone or other mass of matter; and in that sense he
MATTER, ETHER, AND MOTION 86
would be inert, yet no one would think of calling a
sleeping man inert, except in a very loose sense.
Furthermore, there is an experimental analogy that
may help one to see a little deeper into this. Every
one knows what is meant by the “sleep” of a spinning
top. It appears to be absolutely at rest, and may not
even hum; but touch it, and the effect upon it will be
out of all proportion to the slightness of the touch.
It has been observed as a property of vortex rings
that they have a tendency to move forward in the
direction of their axes, and when prevented from going
forward they press upon the body that arrests them.
If they be brought to rest, and then the barrier be
removed, they, of their own accord, start on in the same
direction as if pushed from behind. Such a body cannot
be said to be inert without modifying the common
meaning of the word.
This is not alluded to here as proving anything;
but inasmuch as the vortex-ring theory of matter has
a good probability in its favor, this property I have
mentioned helps one to understand how the atoms
might be other than inert, and yet large bodies of them
together exhibit that property with the rigorousness our
observations upon such bodies demonstrate. Suppose
each atom had the ability to move forward of its own
impulse when not acted on by any other atom. If there
ENERGY 87
were a million atoms joined together, no matter how,
provided they were promiscuously faced, they would
mutually neutralize each other’s ability to move in any
direction, and the resultant of the whole would be that
passivity which we call inertness.
We may by and by see that there may be still other
good reasons for thinking matter not to be so passive
as it has been often assumed to be.
The second law of motion is, when two or more
bodies act upon a third body, the effect of each is the
same as if it alone acted, and the combined effect is
called the resultant; and the third law is, that action
and reaction are always equal and opposite in direction.
This third condition of action, or the relation of motions
in two bodies, is of a high degree of philosophical
importance, perhaps not more so than the others, but
of so much that it is worth while to attend to it more
particularly than to the second law. If a rope be tied to
the wall and one pulls upon it so as to make it taut,
the wall pulls back in the opposite direction as much
as the arm pulls forward. A spring-balance attached
to the wall would indicate the strength of the pull, the
pull of the arm representing the action, and measured
by the muscular vibration, as already described, and
the pull of the wall representing the reaction, and
equal to the action in quantity and maintained by
MATTER, ETHER, AND MOTION 88
molecular vibration. Imagine the action of the arm to
be steadily increasing in quantity: the reaction of the
wall would correspondingly increase until the molecular
tension could no longer be increased, and either the
rope would break, the hook be pulled out from the
wall, or the wall itself be broken away; but in no case
could the action exceed the reaction or vice versa. Now,
if the amount of matter in the arm were a constant
quantity, as well as that of the rope, the hook, and the
wall, then it would follow that all the physical changes
noted in either the one or the other, so far as energy
is concerned, must be due to the motions involved on
either side. And if action and reaction be equal, and
the quantity of matter be uniform, then the amount of
motion involved must be equal on the two sides. If a
body in motion strikes another body, and the second
one is set in motion, the amount of motion in the
two will be just equal to the amount of motion in the
first. The amount of motion gained by one body is
just equal to that lost by the other, and there has been
simply an exchange of motions, one having gained, the
other lost; the one that gained being the one that had
less, and the one that lost having had more, than the
other one. In books of physics it is customary to speak
of the amount of motion a body has as its momentum;
and it may be measured by multiplying the mass of
ENERGY 89
the body by its velocity, and oftentimes one may read
that in the physical exchanges that are all the time
happening in matter the momentum is conserved; that
is to say, is neither increased nor diminished. Seeing,
therefore, that the amount of matter is a constant
quantity, and the momentum a constant quantity, it
follows that the amount of motion is constant. Motion
is conserved as well as matter. If the amount of matter
in the universe be constant, then, according to this
statement, the amount of motion must be constant, and
the amount of energy constant also.
It is generally agreed that this statement concerning
energy is true, and one hears often about the law
of the conservation of energy. It seems to be less
clearly recognized that the third law of motion implies
the conservation of motion, provided matter is itself
a constant quantity. But there is another condition of
things that is as uniform as any other condition of
things in nature that has not been recognized as a law,
and yet it deserves to be perhaps as much or more than
most others, since, in our experience, it is never known
to vary; it is this: Wherever there is an interchange
of motions between two bodies, the transfer is always
from the one having more to the one having less.
As exchange of motions implies transfer of energy, it
follows that all transfers of energy of any given kind
MATTER, ETHER, AND MOTION 90
are from bodies having more to those having less.
Cause and effect are always determined by such
a disposition of things, though not every one has
apparently seen that questions involving what they
please to call causes and effects presume a kind of
antecedent and consequent that always work both ways
at the same time, for there is no such thing as an
isolated phenomenon. If everything takes place so and
so because there is an exchange of motion going on,
then this thing that now moves faster than it did has
been acted upon by a body that had more motion in this
direction than the former one had, and it has imparted
some of its motion at the expense of its own energy.
If one inquires what caused the increased velocity to
this body, it may be said it was caused by the impact
with another body. In like manner one may inquire
what caused the slowing-up motions of the second
body, and the answer still must be, the same impact
with the first body. So, for every phenomenon there
is a corresponding and complementary phenomenon,
which it is just as appropriate to consider as a cause
as it is the first, and either element is just as much a
cause as the other, and in each and every case all there
is involved are exchanges in the amount and kinds of
motion in matter.
There remains now the consideration of a topic
ENERGY 91
which those who have studied physical subjects only
a little must be more or less familiar with. The term
“potential energy” has been much employed within the
last twenty years to express a certain condition of matter
that renders it a source of energy when no motion
is supposed to be involved: thus, where a weight is
raised, like that of a clock, or of a stone raised to the
roof of a house. By falling, either of them can be made
to do work; but so long as they remain raised and are
apparently quiescent, their stock of energy is measured
by their weight into their height, i.e., foot-pounds; and
this is said to be potential energy. Examples of this sort
are numerous. The wound-up spring of a clock or
watch, a bent bow, compressed air or steam, powder,
nitro-glycerine, and the like explosives, coal, wood,
and other kinds of fuel, are all varieties of so-called
potential energy. Let it be remembered that we have
in natural phenomena matter and ether and space and
time and motion. If matter and ether be substances,
then the product of one into the other would signify
nothing; it would be physical nonsense. So likewise
would be the product of matter into space or time;
and yet if matter is to be possessed of energy, and
motion is not one of the factors, then either space or
time must be, and no one can imagine how energy can
in any way depend upon time as a factor, and there
MATTER, ETHER, AND MOTION 92
is no degree of probability that it is or can be so; and
hence, though we had no hint of how it might be, one
would need to avow his belief that in some way motion
was involved in every case where physical energy was
involved, for in any case where it had been hitherto
possible to trace it, it had been found to be present as
a factor in precisely the same relations as in all other
known cases, and hence he would avow a disbelief
in the existence of potential energy in any other than
a loose sense for a condition where the character of
the motion involved was obscure. This would imply
that all energy is kinetic, whether the character of the
motion was determined or not. This view is now held
by those who have taken the pains to think out the
necessary relations that are involved in this subject.
In the last edition of the “Encyclopædia Britannica,”
Professor Tait, who contributed the article on “Mechanics,”
says, “Now, it is impossible to conceive of a
truly dormant form of energy whose magnitude should
depend in any way on the unit of time; and we are
therefore forced to the conclusion that potential energy,
like kinetic energy, depends in some unimagined way
upon motion;” also, “The conclusion which appears
inevitable is that whatever matter may be, the other
reality in the physical universe which is never found
unassociated with matter depends in all its widely
ENERGY 93
varied forms upon motion of matter;” and in another
place, “Potential energy must in some way depend
upon motion.”
It was pointed out (on p. 67) that what was called
physiological work is now known to depend upon
the vibratory state of muscles in a state of tension.
Before that explanation was known, one might have
called such, potential energy, if it had not been for
the sense of fatigue felt by one who was doing such
physiological work that forbade him to assume that
actual energy was not employed to maintain such a
stress; and when it becomes evident, as it has, that
one cannot press upon a table, or pull upon a rope,
or bring about in any way a push or a strain upon
matter, without varying the temperature of the body, it
is no longer difficult to understand that all changes of
that sort upon matter result in atomic and molecular
stresses, for they are placed in abnormal positions as
well as stretched muscles, and their energy is spent
in a similar manner. There is a curious phenomenon
exhibited by all bodies that are made to do atomic
and molecular work for a considerable time. They
become exhausted, like living things, and require rest
to recover their properties. Thus, a tuning-fork, if kept
artificially vibrating for some time, will stop almost
instantly when the driving force is stopped, though at
MATTER, ETHER, AND MOTION 94
the outset it would continue to vibrate for a minute
or more when left to itself. This is caused by what
is called the fatigue of elasticity: the body loses some
degree of its elasticity, and requires time to recover it.
I have called the phenomenon curious. Perhaps it is
no more so than any other phenomenon manifested by
matter; but it is so similar to what is so characteristic of
living things, that it almost excites one’s sympathy. One
can have compassion for an overworked and exhausted
horse, but an overworked tuning-fork! The expression
would seem to be wholly inapplicable, but the fact is
as stated. The only difference between the cases is, one
has nerves, and becomes conscious of the exhaustion,
the other not.
So far, both motion and energy have been considered
as related to matter, and matter as defined in the
first chapter, as distinguished from the ether, though
immersed in it, and can by no means be isolated from
it; but energy exists in the ether as well, as we are
assured by many phenomena. That light requires about
eight minutes to come to us from the sun has been
proved in numerous ways. When it gets to the earth it
is found to be able to impart energy to the matter it
falls upon: it may heat it and affect it in other ways
that are measurable, so energy gets to us from the
sun, and is eight minutes in transit in the ether. If we
ENERGY 95
do not call ether matter, and it has been shown that
there are good reasons for not doing so, then it follows
that energy exists outside of matter, and it is a proper
line of inquiry to learn what shape the energy exists
in, and what mechanical conceptions are appropriate
when thinking about it. In matter one may isolate
motions of various sorts. A mass of matter, say, like a
baseball, may have translatory motion: it may vibrate
or it may spin. In each case one may contemplate the
kind of motion, and compute the energy involved in
the movement, and this is true for atoms as well as
larger masses; but when the substance is not made up
of discrete parts, but is absolutely homogeneous with
no interstices, and apparently incapable of changing
either its position or its form, as there is good reason
for thinking to be the case with the ether, it becomes
much more difficult to picture to one’s self just what
is happening when motion of any sort is involved.
As has already been said, we know that light consists
of waves, measurable quantities, and we know how
much energy reaches the earth from the sun and falls
upon a square mile or square foot. There have been
several estimates of this quantity, and it is found to
be equal to about one hundred and thirty foot-pounds
per second for each square foot section of sunshine.
This signifies, of course, that that is the amount of
MATTER, ETHER, AND MOTION 96
energy in a column of ether one foot square and a
hundred and eighty-six thousand miles long, for that
is the amount that arrives per second. So one may
calculate the amount of energy there is in a cubic mile
of sunlight to be about twelve thousand foot-pounds,
and also that the amount given out by the sun in a
second is about four millions of foot-pounds, or nearly
seven thousand horse-power for each square foot of
the sun’s surface. All of this energy is handed over
to the ether, which distributes it in all directions as
undulatory movements which we call light. Such wave
motions do not exhibit anything like what we call
momentum as waves in water or air always do, and
they are therefore in striking contrast with waves in
matter. Moreover, being waves, having the amplitude
at right angles to the direction of propagation, they
must be compounded of two motions,—a rectilinear
and a vibratory one,—and not a simple one such as a
particle of matter may have.
The ether is capable of being affected by other
motions of matter than simply the vibratory one of
atoms and molecules.
Whenever an electro-magnet is made, it reacts upon
the ether in such a way as to affect other matter that
chances to be in the range of ether so affected. It
appears as if the ether were thrown into a state of
ENERGY 97
stress which it retains so long as the magnet retains its
property; and this condition extends to an indefinite
distance in all directions. If such an electro-magnet is
made and unmade by opening and closing an electric
current in its coils, there will be formed a set of
electro-magnetic waves in the ether which will travel
outwards from the magnet in a manner similar to
light-waves, only they will have an enormous wave
length. If the circuit be closed but once a second, the
waves will be a hundred and eighty-six thousand miles
long; for a wave in the ether travels in it with a velocity
that depends solely upon the property of the ether to
transmit disturbances, and not at all upon the source
of the disturbance. That such an electro-magnetic wave
possesses energy, and can do work, one may satisfy
himself by observing the motions produced by them
upon magnetic needles within the affected space.
In like manner an electrified body puts the ether
into a different kind of a stress from the magnet; and
when this is done periodically, as it may be by an
induction coil, and in other ways, electrostatic waves
are set up, and these too travel with the speed of
light, and are capable of affecting matter to a great
distance, thus showing that the ether may possess
energy in an electro-static form, as distinguished from
the electro-magnetic and light. There are some physicists
MATTER, ETHER, AND MOTION 98
who think these last two to be identical, and the
reasons for their opinion will be given in a subsequent
place.
It only remains to point out that whatever the
nature of gravity may be, there can be very little doubt
that the ether is intimately concerned in it, as Sir Isaac
Newton supposed was the case. But if it is, and ether
is the agency by which one mass of matter is able to
affect another mass, then ether is in a state of stress
produced by the atoms of matter all the time, and
therefore in some way gravitative energy is lodged in
it. As the ether is so universal in its extension, one
cannot but see that it is a storehouse of an almost
unlimited amount of energy of many kinds; so that
if every particle of matter were instantly annihilated,
there would still be a universe filled with energy,
though it might not be serviceable, because lacking the
conditions for transformation into useful forms. This
may be said to be one of the functions of matter—the
transformation of the energy it gets from the ether.
GRAVITATION 99
CHAPTER V
Gravitation
That all bodies will fall towards the earth if raised
above its surface and left unsupported everybody knows
and must always have known, for it is a fact thrust
into everybody’s notice constantly and as long as he
lives. Also that bodies resting upon the earth require
energy to be spent in order to raise them from it is
equally well known. Thus all bodies act as if they
were attracted by the earth, and the weight of a body
is the measure of the attraction of the earth upon it.
One not unfrequently comes across statements by
authors implying that Newton was the discoverer of
this attraction which is called gravitation. This is a
mistake: not only was this idea common in Newton’s
day, but the word itself was in extensive use. Kepler
had affirmed that the sun attracted the earth and the
planets, and Galileo had busied himself very much
with the study of attraction of the earth upon bodies.
The problem that Newton had before him was not as
to the existence of gravitative action, but what was
its law of operation and the limits of it, if it had
MATTER, ETHER, AND MOTION 100
any limits. The familiar story of the fall of the apple
leading to the great discovery is generally believed to be
mythical; at any rate, other facts well authenticated do
not accord with that story. When he was twenty-three
years old he undertook to apply the law as we now
have it, to the moon, using the size of the earth and
the moon’s distance from it, as they were then best
known. The result satisfied him that his surmise could
not be the law, if the measure of the earth then had
was accurate. This was in 1666. In 1683 he learned of
some new measures recently made of the magnitude
of the earth, indicating it to be larger than had been
supposed. Then, with the new measures for data, he
made a new computation. It was then, when he saw
that the results were to prove his conjecture, and he
perceived the immense importance of the discovery, that
he handed over the unfinished work to an amanuensis,
because he was too much agitated to complete it. If the
discovery was made when he first thought of putting
the idea to the test, it is strange that his emotional
excitement should have been postponed for seventeen
years. Evidently it was at the latter date when he
thought he had made the discovery. It was the law
of gravitation that Newton discovered, and that it was
universal. Every particle of matter attracts every other
particle; and the strength of this attraction varies as
GRAVITATION 101
the mass of each, and inversely as the square of the
distance between them. Thus, if at the surface of the
earth gravitation gives a weight of one pound to a body,
at the distance of ten radii of the earth = 40000 miles,
the weight would be 1
102 , one-hundredth of a pound,
and at the distance of the moon, or sixty radii of the
earth, the body would weigh but 1
602 =one thirty-six
hundredth of a pound, and would fall towards the
earth in a second but 1
3600
of the distance it would
fall at the surface of the earth, where it is about
sixteen feet. One thirty-six hundredth of sixteen feet
is about the one 1
224
of a foot, which is therefore
the departure from a straight line the body at the
distance of the moon must make per second to move
round the earth. The mutual attraction of these bodies
at that distance is sufficient to produce this amount
of deflection, and hence accounts for the rotation at
that distance. When the same mathematical relation
is applied to the planets, comets, and meteors that
revolve about the sun, it is found to be applicable to
every one of them; and in the depths of space in every
direction are to be seen multitudes of stars revolving
about each other in similar manner, and hence it is
concluded that gravitation is a universal property, and
MATTER, ETHER, AND MOTION 102
the law is applicable throughout the universe.
There are other kinds of attraction that matter
exhibits, such as electric and magnetic, that follow a
part of the above law, but do not the other part.
The law regarding the distance is true for electrified
bodies, but the mass of the bodies does not enter
as a controlling condition. So it appears that the
variability of attraction with the distance is a geometrical
condition, and depends upon the property of space,
and is not peculiar to any physical phenomenon.
Sound, light, heat, electricity, magnetism, as well as
gravitation, exhibit the property, as do circles and
spheres. The peculiar thing about gravitative attraction
is that it depends upon the masses of the attracting
bodies, and is not modified in the slightest degree by
the interposition of any substance of any magnitude
between the attracting particles or masses. In this
particular it is strikingly unlike magnetic attraction. If,
for instance, a piece of iron is brought between two
magnets that at a distance are attracting each other, the
strength of their action upon each other is decidedly
less. The strength of the attraction of the sun is just
as great upon a particle in the centre of the earth as
for any similar particle at an equal distance that is not
shielded.
There have been numerous attempts in the past
GRAVITATION 103
to account for gravitation. It has been imagined that
space was full of particles swiftly moving in every
direction that produced a pressure upon all bodies by
their impact; that each body shielded other bodies in
a measure, and hence the pressure produced upon the
adjacent sides would be less than elsewhere, and, as
a consequence, each body would be pushed in the
direction of an adjacent body. But a push represents
expended energy, and this would imply that the moving
particles must be losing energy at the expense of their
velocity; and as no such particles are known, and if there
were, their velocity would have to be so much greater
than that of light, there is no degree of probability
to be allowed for the idea. The effect of vibrations
upon the ether has been a very common manner of
attempting to explain gravitation. It has been observed
that if light bodies are brought near to a vibrating
body like a tuning-fork, they are apparently attracted
by it so long as the vibratory motion continues; and
the action is explained by the rarefaction produced by
the vibratory motion, which reduces the pressure in
the space about the body, so when another body is
brought near the pressure is greater on the remote side
than it is on the side adjacent, and thus the body is
pushed towards the one vibrating. It is known that
all the atoms of all bodies are in a state of vibration
MATTER, ETHER, AND MOTION 104
at all temperatures; and hence it was inferred that
the pressure of the ether must be reduced next to
their surface, so that between two atoms or molecules
the pressure must be less than external to them,
and hence the pressure of the ether will crowd them
together. This idea has been worked out by a large
number of persons in different countries. There are
two fatal objections to this hypothesis: First, it would
make the attraction of gravitation dependent upon their
temperature, and there is no evidence to show that
temperature makes any difference; and second, that the
velocity of gravitative action is the same as that of light.
There is an abundance of astronomical evidence, that
if it has any velocity at all it must vastly exceed that
of light. If it were as much as a million times greater,
astronomical phenomena would exhibit it plainly.
Seeing that every particle of matter in the universe,
affects every other particle in a certain and definite
way, no matter what the distance between them, there
must be either the possibility that a body can act upon
another one at a distance without any medium between
them,—which is called action at a distance,—or there
must be a medium which is first affected by the bodies,
and which in turn reacts upon other bodies in it.
What Sir Isaac Newton thought of these contingencies
was cited in a former chapter (see p. 36). It is now
GRAVITATION 105
generally felt to be not only essential for consistent
mechanical thinking, but that in some way the ether
which is known to exist must have some essential part
in the phenomenon. It has been the subject of curious
speculation why Newton should so strongly state his
belief in the existence of a medium for the propagation
of physical conditions, and yet in his work on light
he should adopt the corpuscular theory—that light
consisted of emanations, which was a practical denial
of the hypothesis of the ether. The explanation of the
anomaly is probably in the fact, that he could treat
in his mathematical way the ideal corpuscles, while he
could not so treat the ether hypothesis of waves. His
work was developed with ideas he could handle; and
the outcome of it was that the science of light was
retarded by his misconceptions for a hundred years, for
every one now who knows anything about it knows
that Newton’s hypothesis was a wrong one. There
are some persons who would curb the imaginations of
others in physical things by quoting Newton’s dictum,
“Hypotheses I do not touch,” but they omit to mention
that Newton’s work on optics was altogether based
upon a hypothesis that has wholly broken down. Every
one of the explanations he gave of such phenomena is
worthless, and no one gives attention to them except
for their historic relations to the science.
MATTER, ETHER, AND MOTION 106
It has been thus in other lines. A symbolic
representation of things such as offers the possibility of
mathematical treatment has been seized and worked out
to great length, when the actual phenomena pretended
to be treated gave no countenance to the conceptions.
Such has been the case in electricity and magnetism
and heat. The mathematicians fought Ohm’s, Faraday’s,
and Joule’s mechanical conceptions until death stopped
them.
It is certainly true that all physical phenomena
are subject to strictly mathematical conditions, and
mathematical processes are unassailable in themselves.
The trouble arises from the data employed. Most
phenomena are so highly complex that one can never
be quite sure he is dealing with all the factors until
experiment proves it. So that experiment is rather a
criterion of mathematical conclusions and must lead
the way. Mathematics is a deductive science, yet the
number of physical facts or phenomena that have been
discovered by its aid is so small that they may almost
be left out of the count. There is the discovery of
the planet Neptune, that has been spoken of as a
triumph of mathematical science, yet one of the most
competent mathematicians that ever lived—Professor
Peirce of Harvard—declared that it was only a lucky
find, for the computations would apply just as well to
GRAVITATION 107
a planet 180 from it. The conical refraction of light
is another one. Altogether they make but a small
figure and are unimportant. The law of gravitation
was discovered by trial, and although its importance is
second to none other yet discovered, it happens that
it is one of the very simplest and least complicated
with other laws we know of; but an explanation of
how it can act thus, or why it exists at all, or what
its antecedents are if it has any, these are questions
that are matters for the guessers, like Kepler, who kept
guessing until he guessed right, and so discovered what
are known as his laws. Meanwhile definite mechanical
conceptions of what the phenomena to be explained
are like may be helpful to those interested in them.
Suppose two bodies, A and B, a certain distance
apart, and they so react upon each other that they tend
to mutually approach each other. Given a medium,
ether, can one imagine stresses set up by either body
in the ether that will be capable of affecting the other?
Imagine a large space like a room occupied by
glass of uniform texture and properties throughout. If
relieved of gravitational property, the cohesion of all
its parts shows that every particle is in some sort of
stress, no matter what the origin of that may be. Now,
suppose there could suddenly be created somewhere
near the middle of the glass a bullet or a marble. It
MATTER, ETHER, AND MOTION 108
would displace so much glass as would be equal to
its own volume, and the result of that would be that
the glass about it would be subject to a new stress,
which would be greatest, at the surface of contact
of the marble, and would be less as that surface is
receded from inversely proportional to the square of
the distance of the point of observation. If the glass be
imagined to be indefinitely great in magnitude, then
the stress would extend in every direction through
the whole extent of it, and at any assignable point
would still be in accordance with the inverse law,
diminishing outward. Imagine now another similar
marble to be created at the distance of a foot from the
first. Inasmuch as it displaces so much glass it will
set up a new stress in the latter, and this stress must
also be transmitted throughout the whole mass as in
the first instance. Now, here will be two independent
stresses overlapping; and on account of the nature of
the stress, it will be greater between the marbles than
it will be anywhere else, because there the sum of
the stresses will be at a maximum. If one can now
for the moment imagine that the glass was of such
constitution as to permit a motion to the marbles,
in any direction, when there was a stress tending to
move them, it would be obvious that the marbles
would separate from each other as the medium, the
GRAVITATION 109
glass, was under greater tension between them than
in any other direction.1 And if the glass thus mobile
was indefinite in extent and without friction, the two
marbles would continue to separate indefinitely. The
energy making them thus to move comes directly from
the medium, which in turn got it from the bodies
themselves when they were thrust into it, no matter
how. Such a phenomenon as separation in a manner
like the above is exactly opposite in character to that
of gravitation, but it points at once to a consideration
of the condition necessary to be similar. It was the
forcing of new material into space already occupied
with other material that developed the stress and led
to the above results. It will be necessary to find a way
to develop a stress towards a point instead of away
from it.
Suppose, then, that instead of having a created
something imbedded in it, a cavity of equal volume to
the marble should be produced in its place. As part
of the material of the medium has been annihilated,
there will now be a less stress at its bounding surface
than there was when it was occupied with material,
and the direction of the stress will now be towards
the cavity. That is, the stress will be less there than
1Such bodies might be said to have negative weight.
MATTER, ETHER, AND MOTION 110
anywhere else in the glass; and this, too, if measured,
will be found distributed like the other, inversely as
the square of the distance from the origin. Let another
similar cavity be produced in the neighborhood of the
first, and the two stresses will overlap, and there will
be less between them than in any other direction. Let
us imagine now that the glass was mobile enough
to permit the movement of either of these cavities in
any direction towards which there was any pressure,
and they would approach each other because pushed
by the stress in the glass more towards each other
than in any other direction. If one of these cavities
were larger than the other, one would expect that the
corresponding stress would be greater, and so there
would be a stress that for direction and the resultant
movement would correspond with what is observed in
the phenomena of gravitation.
But such a conception as that of a vacuum as
constituting what we call the atoms of matter has
no mechanical validity at all. Atoms have not only
volume, they have mass, and that requires energy to
displace. One cannot imagine that the displacement of
an absolute vacuum, if such a thing could be done,
would require any energy, for there would be no mass
to move.
Suppose, however,—instead of imagining, as was
GRAVITATION 111
done, the entire volume of the marble to be destroyed,—
that in some way the volume of the glass marble had
suddenly been reduced, no matter how, and that the
diminished volume was retained,—the material had been
condensed. This would bring about the same relative
condition of stress to the condensed portion, so that
there would be less adjacent to it than elsewhere, the
measure of it being the actual amount of condensation
represented in the body. What would be true of one
would be true of others,—an indefinite number,—and
no number of such stresses would in any manner
interfere with or neutralize that of others. At any
point of the space filled with such glass each such
condensation would have produced its effect at the
outset, and if the glass were practically limitless in
extent this relationship would be maintained so long
as the reduced volumes remained constant.
So far has been considered a condition of things
somewhat analogous to gravitation; and to apply it
one needs to imagine the ether to be substituted for
the glass and the atoms of matter for the imagined
condensation, and also that the two, the ether and
atom, are capable of mutual reaction.
There have been some physicists who have imagined
that the atoms of matter were condensations in the
ether, but I am not aware that any very satisfactory
MATTER, ETHER, AND MOTION 112
reasons have been given for thinking so. That in itself
would be no reason for rejecting the idea in the absence
of a better and more consistent one. For scientific
purposes a poor hypothesis is better than none at all.
A very large amount of scientific work has been
done by employing hypotheses that are now known to
be wrong. A working hypothesis is needful. If it be
wrong, one will by and by find it out and be able to
amend it, or replace it by a better. If it be right, it will
be vindicated, and will justify itself, and be generally
adopted.
Until we know more definitely than is now known
what the constitution of matter really is, one can only
guess and try; and among the multitude of interested
workers in all civilized countries there will be some
who will guess right to the advantage of all.
If, then, one adopts the vortex ring theory of matter,
and endeavors to trace the mechanical conditions that
might obtain with such kind of atoms, he would be
led to inquire whether a vortex ring does or does not
exhibit any evidence of condensation in the material
that is in rotation; that is, does the material of the
ring occupy the same space while it is in rotation as
it does when not?
There are several phenomena that seem to show
that it occupies less space. The reduction of pressure
GRAVITATION 113
in its neighborhood shows a rarefaction there, and
the mutual approach of such rings and of other light
bodies in their neighborhood indicates the same thing.
If one rotates a disk rapidly, any light bodies in front
of it will tend to approach it even from a distance of
several inches. If a dozen disks five or six inches in
diameter are set loosely an inch apart upon a spindle
a foot long, so that they may be rotated fast, yet left
free to move longitudinally upon the spindle, they will
all crowd up close together as the pressure is less
between them than outside. If one can imagine the
spindle to be flexible and the ends brought opposite
each other while rotating, it will be seen that the ends
would exhibit an apparent attraction for each other,
and, if free to approach, would close up, thus making
a vortex ring with the sections of disks. If the axis
of the disks were shrinkable, the whole thing would
contract to a minimum size that would be determined
by the rapidity of the rotary movement, in which case
not only would it be plain why the ring form was
maintained, but why the diameter of the ring as a
whole should shrink. So long as it rotated it would
keep up a stress in the air about it. So far as the
experimental evidence goes, it appears that a vortex
ring in the air exhibits the phenomenon in question.
There is no doubt at all that two vortex rings in the
MATTER, ETHER, AND MOTION 114
air attract each other, for they will mutually approach
if free to do so, and the explanation is plain that there
is reduced pressure between them; in other words,
the characteristic motion of the ring reduces the air
pressure about it, so that another body within that
field is pushed towards the place where the pressure
is least. The reduction of the pressure about any ring
must evidently depend upon the amount of material
embodied in it, and more especially the degree of
rotation which it has. A small, thin but rapidly rotating
ring might produce as great a rarefaction about it as
a much larger one with less velocity, hence there is
something about it that corresponds to what is called
mass. It is not simply an amount of material, but the
energy the material has, which gives it its characteristic
properties.
Analogy must not be mistaken for identity. There
is so great a difference between the properties of the
air and other gases and those of the ether that one
cannot affirm that what holds true of one must hold
true of the other; yet that is what is generally done by
such persons as those who try to show the properties
of the ether to be identical with those of matter.
We know what conditions are necessary in order
that a ring should be formed in the air, and one of
them is that there must be gaseous friction. If that were
GRAVITATION 115
not the case a ring could not be formed. If the ether
be the frictionless medium it is generally supposed to
be, one would not know how to make a vortex ring in
it. On the other hand, the reason a ring in the air is
so soon destroyed is because of friction; and hence if
one were made in some unimagined way in the ether
it would continue to exist indefinitely, but how it could
act at all upon the ether surrounding it would be a
mechanical puzzle, and that is the present state of the
case. The puzzle is no greater with the conception of
a vortex ring than if the atom were made up in some
other way, and therefore that objection is not peculiar
to this hypothesis. It has been confessedly a puzzle to
see how the vibratory motions of atoms and molecules
could set up transverse waves in the ether if the ether
be without friction; nevertheless, they do set up such
waves. A common objection to all attempts that have
been made to account for gravitation by means of the
motions of the atoms themselves is that it not only
requires a constant expenditure of energy, but that the
velocity of transmission must be so much greater than
that of light. Light is transverse vibratory movement.
A direct longitudinal wave may be much swifter than
the other. A pull upon a taut rope will travel much
faster in it than will a wave produced by a transverse
movement of the hand.
MATTER, ETHER, AND MOTION 116
It is not to be understood that what is presented
here is given as a proof that gravitation is but a simple
mechanical condition of things. It is probable that every
one who thinks about it believes that its explanation
is purely mechanical. Some perhaps are pessimistic,
and doubt that man will ever be able to understand
its mysteries, but pessimists are not discoverers. They
frequently so chill the air about them that more hopeful
ones, who are not persuaded that the end has yet been
reached, are sometimes deterred from venturing into
fields where they have to pass such self-constituted
gate-keepers.
There are few physical problems of any generality
and complexity that are abruptly and completely solved
by one person. Tentative steps must be taken, and
much labor is oftentimes spent upon ideas that by and
by are proved to be worthless. A good deal of the
work done by Laplace upon the Nebula theory was of
that sort; yet all astronomers hold the Nebula theory
in some form: what the exact process was, if solely
mechanical, may be interesting, but not very important
from a philosophical standpoint.
So one may hold that gravitation is a mechanical
action, and in some way explainable on mechanical
principles, even if he does not see how at all.
This chapter may help some to see not only what
GRAVITATION 117
the character of the problem is, but what factors are
present, and how somewhat similar phenomena may
be reproduced at will; but the radical distinction that
exists between the ether and matter must always be
kept in mind.
MATTER, ETHER, AND MOTION 118
CHAPTER VI
Heat
Heat and cold are two words we apply to
contrasted sensations, either of which may imply
comfort or discomfort; and what is meant by either
word in a given case depends altogether upon what the
sensation is compared with. Thus, one would speak of
a day when the thermometer indicated one hundred
degrees in the shade as being a hot day, while if his
cup of coffee had the same temperature it would be
called cold; so the terms imply only roughly some
departure from a standard of comfort. To obtain more
definite knowledge of that physical condition which
gives us the sensation we call heat, it is necessary to
attend to its origin and its effects upon other bodies.
I. MECHANICAL ORIGIN.
When a blacksmith hammers a small piece of iron,
like a nail, upon his anvil, it becomes too hot to hold,
and it even may be made to glow, red-hot, by the
repeated blows of the hammer. If a bullet be shot
HEAT 119
against a target and be quickly picked up, it is found
to be hot; and in general the impact of any two bodies
always results in heating both of them. In the above
cases both the hammer and the target are heated, but
on account of their size the degree of heat is not so
noticeable as it is with the smaller bodies.
In like manner if the knuckles be rubbed briskly upon
one’s sleeve, the sensation of heat becomes unbearable
in a very brief time. The friction of the surfaces
develops the heat, as may be learned by taking a button
or some similar object, and in the same brisk manner
rub it on the sleeve or other convenient surface, and it
will get too hot to be safely touched against the skin.
On a larger scale the brakes upon railroad-cars exhibit
the same quality when they have been applied for a
few seconds. The sparks that may be seen flying from
them in the dark is testimony to the same thing; while
the car-wheel boxes are often so heated by the constant
friction when the lubricating oil is wanting, that the
cotton waste takes fire, and even locomotives may be
delayed by their hot journals. This source of heat is so
common that instances may be cited indefinitely. It is
universally true that the friction of one body moving
in contact with another heats them both, and the heat
developed depends upon the pressure and the velocity
of the moving surfaces. It is true not only for solids,
MATTER, ETHER, AND MOTION 120
but for liquids and gases as well, and the friction of
solids moving in either liquids or gases. An extreme
case of the latter kind is illustrated by the shining trail
of a meteor when it enters the atmosphere. Its velocity
is very great—twenty or thirty miles a second—and
the friction of the air is so great on account of the
high speed that it renders the surface of the meteorite
red-hot, and some of its molecules are ground off as
they would be if it were held against a swift turning
emery-wheel that scatters the sparks in the air. The
luminous trail consists of these heated particles. If the
body is not large, and most meteors are quite small,
they may be entirely ground to powder and dissipated
before they can reach the earth. Most meteors in this
way rarely pass through more than fifty or sixty miles
of our atmosphere before this happens.
Another mechanical source of heat is compression.
Let a bullet be hard squeezed in a vise, or in any
other way, and it is found that its heat is perceptibly
increased. Small differences of this sort may be easily
detected by the use of the thermopile and galvanometer.
The rubbed button or pounded or squeezed bullet
placed upon the face of the thermopile shows the presence
of an amount of heat which the sense of heat would
HEAT 121
Diag. 4.
Diag. 5.
never detect. Gases exhibit the heating effect
through pressure in a high degree. Before
the invention of friction matches, which are
themselves good examples of the production of
heat by friction, metallic tubes, closed at one
end with a tight-fitting plunger to be worked
by hand, were in common use for lighting fires.
A bit of punky wood was fixed to the end of
the plunger, and the latter was then quickly
driven to the bottom of the tube. The air was
compressed to so great an extent that the heat
developed became sufficient to ignite the punk. The
same heating effect of compression may be shown by
MATTER, ETHER, AND MOTION 122
the thermopile and galvanometer by compressing the
air with an air-condenser, and permitting the air thus
condensed to strike on its exit upon the face of the
pile.
Thus impact, or sudden stopping of mechanical
motion, friction, or the gradual stopping of mechanical
motion and condensation, or compelling molecules to
occupy less space, all of them of a purely mechanical
nature, result invariably in heating the matter that is
subject to the action.
II. CHEMICAL ORIGIN.
The heat that results from the combustion of fuels
of all sorts is due to the chemical changes that take
place. When coal burns, its substance, carbon, is
entering into combination with the oxygen of the air,
and a new chemical product is formed called carbon
dioxide, which is a gas; and the change is accompanied
by the production of a large amount of heat, which
we utilize for our comfort or for the various arts that
depend upon heat as an agent. Wood, alcohol, the
various oils,—everything capable of burning, and which
may be called fuels—are, in the process of burning,
undergoing what is called oxidation, in which new
chemical compounds are formed and which are nearly
HEAT 123
all gaseous. Thus the products of the combustion of
wood, alcohol, coal-oil, etc., are always carbon dioxide
gas, and the vapor of water; and the heat developed
is proportionate to the amount of these produced.
But combustion is not the only chemical source. If
sulphuric acid be mixed with water, the compound
becomes very hot although it is liquid. The two
substances enter into an intimate chemical combination.
A pint of each mixed together will not make a quart,
but will fall short of that volume a good deal when
they have cooled. This shows that condensation has
taken place; and, knowing that condensation produces
heat when brought about in other ways, one might
have suspected that chemical condensation would result
in a similar development of heat.
Some substances when in a finely divided state,
though what we generally call solids, are capable of
entering into combination with each other at a very
rapid rate and then develop a great deal of heat. Such
a substance as gunpowder, a combination of carbon,
sulphur, and the nitrate of potash, when intimately
mixed, will combine with explosive violence, and great
heat results from it, as shown by the attending flash
and the scorching effects it produces upon some bodies
that do not happen to be destroyed by the explosion.
All chemical reactions whatever involve in some degree
MATTER, ETHER, AND MOTION 124
temperature changes; and by so much one might be
led to suspect that there might not be so great a
difference between the mechanical sources of heat at
first considered and the more obscure chemical ones
as one might think who attends only to the more
prominent features of the two. If one should adopt for
a basis of his philosophy that like causes produce like
effects, what shall he say when he sees the same effect
produced by pounding with a hammer, condensing
a gas, and burning a piece of wood? Either unlike
causes can produce similar effects, or fundamentally
these three processes are the same. We will attend to
that question more at length farther on.
III. ELECTRICAL ORIGIN.
As a chapter is to be given to electricity and its
phenomena, it will be sufficient here to point out
that wherever a current of electricity is flowing in a
conductor, there heat is invariably produced. The heat
in an electric arc is so great that all known substances
are either fused or volatilized in it. Gold, platinum,
the ruby, are easily reduced to the liquid form, and
the diamond slowly wastes away, being oxidized like a
piece of coal. Electric furnaces are now in use where
the most refractory substances, like clay, are reduced,
HEAT 125
and the metal aluminum extracted from it. So long as
it cost so much to produce electricity as it did before
the dynamo was perfected, no one could afford to use
it for heating purposes. Now there will shortly be
electric heaters in houses, replacing stoves for cooking
and furnaces for warmth. The electrical current can be
brought on the wire where it is wanted, and the heat
developed from it to any degree desired. Electricity,
then, is another source of heat.
IV. RADIATIVE ORIGIN.
When one stands near a blazing fire the warmth
felt does not come from the heated air between the fire
and the person; for when one shields his face or hands
the warmth ceases to be felt, though the temperature
of the air might be the same in both cases.
In like manner sunshine warms the earth, although
between the sun and the earth there is an enormous
space without air or other matter, through which the
sun’s rays come producing warmth when they get here.
This process of giving out rays to the ether independent
of matter, which is possessed by hot bodies, is called
radiation. It has been shown that all bodies are at all
times giving out such radiations; and oftentimes the
radiation itself is called radiant energy, sometimes it is
MATTER, ETHER, AND MOTION 126
called light, and sometimes simply ether waves. Here
we do not attend to the origin of the waves, but to
the fact that when such waves fall upon matter they
result in heating it, and therefore radiation must be
looked upon as a fourth source of heat.
I would again suggest the thought presented a page
or two back, as to the similarity or dissimilarity of each
of these four kinds of origins of heat,—mechanical,
chemical, electrical, radiant. They appear to be utterly
unlike each other, yet their effects upon matter are
identical, always thus and never different, so far as our
experience goes. Evidently there must be some factor
common to them all; and if this could be known for
any one of them, it would throw light upon all the rest.
If we take, for instance, the mechanical origin of heat,
say, impact, which is one of the most obvious, and
note the factors present, it is plain there are but two;
namely, a mass of matter with a certain measurable
amount of motion of the translational variety. These
two embody the energy represented by the impact, and
of these the translational motion is destroyed when the
heat appears. The other factor, the mass of matter,
remains constant. The motion that was seen needs to
be accounted for; and as the heat that appears is the
result of that motion, it appears probable that in some
way the translational motion has been transformed
HEAT 127
into some other kind of motion, not that it has been
annihilated.
TEMPERATURE.
If a pint of boiling-hot water be mixed with a pint
of ice-cold water, the mixture will have all the heat
there was in the pint of hot water, but it would not
injure the hand thrust into it. The heat that was in
one pint has been distributed through two pints, and
hence each pint has one-half the heat that was in the
hot pint. A red-hot bar of iron will be cooled by
being thrust into a pail of water. The water will be
heated, and will have all the heat the bar lost; but as
it is distributed through so great a volume of water,
the amount of heat in a cubic inch of it will be but a
small proportion of the whole.
The word “temperature” is used to denote the degree
of heat there may be in a unit volume of a substance,
and this is measured by means of thermometers in
which the property that heat possesses of expanding
the volume of bodies is made to indicate their degree
of heat. The standard for this is an arbitrary one
altogether. In the common Fahrenheit thermometer
there is a tube of glass with a bulb upon it filled
with mercury. This, when put into ice-water, acquires
MATTER, ETHER, AND MOTION 128
the same temperature, and the mercury stands at a
certain height in the tube, which is marked. Then it is
put into boiling-hot water, where the mercury expands
and reaches another height in the tube, which is also
marked. The space between the two marks is divided
into one hundred and eighty equal parts, and the same
scale of division is carried beyond in both directions.
A point thirty-two of these divisions below the mark
of the melting ice is called zero; so between it and the
boiling-point are two hundred and twelve divisions,
called degrees. The centigrade thermometer is more
generally used in scientific work. In this the space
between the freezing and boiling points is divided
into one hundred equal parts, called also degrees. A
centigrade degree is 9
5
larger than a Fahrenheit degree.
The scales of either may be extended indefinitely for
the measurement of temperatures departing from the
more usual ones. For a lower limit one cannot use the
mercury below about forty degrees below zero; for it
freezes at that temperature, and no longer follows the
same law of contraction. As alcohol does not freeze,
thermometer tubes filled with it are used to indicate
such low temperature. In the Arctic regions, and even
in Siberia, the temperature falls to fifty or sixty degrees
below zero not infrequently in winter, but temperatures
HEAT 129
have artificially been produced as low as 400 below
zero.
For the higher limits mercury thermometers can be
used for higher temperatures than alcohol, for the latter
boils and becomes vapor at 174. The following table
of temperatures may be interesting:—
Absolute zero . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 􀀀460
Lowest degree artificially produced . . . . . . . . . . . . 􀀀400
Lowest degree measured in Siberia . . . . . . . . . . . . . 􀀀72
Mercury freezes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 􀀀39
Water freezes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 32
Blood in man . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 98.6
Temperature observed in India . . . . . . . . . . . . . . . . . 140
Alcohol boils . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 174
Water boils . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 212
Lead melts . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 612
Mercury boils . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 650
Red heat visible in dark . . . . . . . . . . . . . . . . . . . . . . . . 1000
Silver melts . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1873
Gold melts . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2200
Iron melts . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2700
Platinum melts . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3600
Gases, like liquids and solids, are increased in
volume by heat when permitted to expand. If not
permitted, the pressure upon the walls of the containing
vessel is increased; and it is found that this pressure
is proportionate to the temperature, and also that
the pressure diminishes about 1
273
for each centigrade
MATTER, ETHER, AND MOTION 130
degree of cooling, starting at the freezing-point of
water. If, therefore, a gas could be cooled from that
point 273 centigrade, it would have no pressure, as
it would have no temperature. Such a degree has
never yet been reached; but all phenomena having any
bearing upon the subject indicate that at 􀀀273 there
is no heat: it is an absolute zero. The molecules
Diag. 6.
would have no translational motion, otherwise
they would produce some pressure upon the
walls of the vessel that contained them. Air
thermometers may be made with bulbs blown
upon the end of a glass tube. A small drop
of water in the tube will be pushed in or
out as the temperature varies, and is much
more sensitive than ordinary thermometers; but
barometric pressure affects it and renders it
unfit for common use, but its indications are
proportionate to the absolute scale; that is, the
volume of the air at the melting-point of water will be
increased or diminished 1
273
by every change of one
degree in cooling or heating, or d f rac1490 if the degree
be Fahrenheit.
HEAT 131
MECHANICAL EQUIVALENT.
For a long time it was supposed that heat was a
kind of substance that ordinary matter could absorb
and emit. It was sometimes called caloric; and that
word is in common use to-day, but not in the sense it
originally had. Sometimes it was spoken of as one of
the imponderables—a substance without weight. Now
there is only one imponderable recognized, that is the
ether. Sir Humphry Davy and Count Rumford found
they could produce an indefinite amount of heat by the
friction of one body upon another; and that implied if
heat was a substance of any sort, that any piece of
matter contained an infinite amount of heat, else one
could get out of a body what was not in it. These
two men concluded that heat was a kind of molecular
motion, and that what their experiments showed was
that friction only transformed the mechanical motion
into molecular motion, which was called heat.
The old conceptions had got so thoroughly incorporated
into both the thoughts and the writings of others,
that they could not easily be dislodged, and men went
on as they had done. It was easier to do that than to
change notions and terms that were familiar for others
that were strange, even if true. A whole generation of
men had to be buried before any attention was paid to
MATTER, ETHER, AND MOTION 132
what had been proved in the early part of the century.
Soon after 1840 it occurred to a number of persons in
different countries that if heat were but transformed
mechanical motion there should be some quantitative
relationship between them that might be discovered;
that is, a given amount of mechanical motion ought to
produce a definite amount of heat, and vice versa. This
was worked out in the most complete and satisfactory
way by Joule of England. His method consisted in
churning a definite amount of water and observing
the rise in temperature in it. The churn paddle was
driven by a known weight falling a known distance,
and therefore the work done in driving the paddles
was known in foot-pounds. In this way he found that
772 pounds falling one foot would heat a pound of water
one degree, and he called this number the mechanical
equivalent of heat. In like manner it is said that when
a pound of water loses one degree in temperature, it
has lost energy enough to raise 772 pounds one foot
high. This relationship renders it easy to determine the
amount of work a given amount of heat can do, and
also the temperature that will be acquired by a given
amount of water when a definite amount of work is
done upon it. But the scientific importance of this new
step is much greater than its practical utility. Before
that time men had thought there were such things as
HEAT 133
forces, independent of each other; and such an idea
as mutual convertibility had not dawned upon any
philosophic mind. Physical philosophers were so much
misled by their terminology and the accompanying
notions, that Joule’s work, though demonstrative, made
no impression upon them for several years, and it was
refused a place in the transactions of their society for
seven years. The reason for this common hostility to
new knowledge is probably not far to seek. When one
has achieved distinction in his line of work, especially
in physical science, he is likely to possess his own
philosophy of things, in which not a small part of
the data is symbolic and is represented in mind only
by a name; and if this chances to suggest something
mysterious, as, for instance, an imponderable, the less
is one likely to attempt, or suffer others to attempt,
to displace it by definite mechanical conceptions. To
change one’s fundamental conceptions necessitates a
change in his philosophy throughout,—a change that
is not only difficult, but highly distasteful; and one
ought not to expect a welcome to a man whose work
necessitates such a change.
Within the present century the advance in all
directions has been such as to give definite mechanical
conceptions and relations where before only ghosts
and genii were supposed to do duty; and what can a
MATTER, ETHER, AND MOTION 134
man do when his genii have been slain and he must
now depend upon mv2? To become acquainted with
his new associate is generally the last thing he sets
himself about. It was with Joule as it was with all the
prophets and discoverers. Joule, however, was young,
and he lived to attend the funeral of all his detractors.
That heat and work are mutually convertible is now
called the first law of thermo-dynamics; and it has led
directly to a knowledge of the working-power there
is in fuels, and made the duty of steam-engines and
other sources of power beautifully simple.
The amount of heat needed to raise the temperature
of a pound of water one degree Fahrenheit is called
a heat unit. The amount of heat needed to raise the
temperature of a kilogram of water one centigrade
degree is sometimes called a calorie, and this is a unit
in common use. It is found by careful experiment
that a pound of coal when burnt gives up 14500 heat
units, or would raise the temperature of 100 pounds
of water 145, or to any other equivalent. A pound of
hydrogen, in like manner, burning with oxygen, will
give 61000 units, a pound of wood about 7000, and so
on. Each different substance has its own equivalent of
such heat units. As each unit will do 772 foot-pounds
of work, a pound of coal, when burnt, will give
14500  772 = 11, 194000 foot-pounds of work, and so
HEAT 135
on for any other. This equivalency is independent of
time or place. Whether the coal burns fast or slow
makes no difference. When wood is burned in the fire
it develops its work-power fast; but when it slowly
rots it is undergoing the same process, oxidation, and
the same amount of heat is developed, though at no
time does the temperature appear to be above that
of surrounding things. The food we eat possesses its
mechanical equivalent, which is the maximum amount
of work it would enable one to do. If bread and butter
were used for the fuel of an engine, it would develop
about 21000 heat units (or calories) per pound, and this
is equal to 772  21000 = 16, 212000 foot-pounds, and it
has the same value when used for food; and thus one
may know approximately the amount of energy he is
supplied with from day to day; also, he may compare
the amount of work he does, in lifting, walking, or
otherwise, in a day with the food equivalent absorbed.
Some of this is, of course, used to maintain the
temperature of the body, the circulation of the blood,
and so on—conditions that are tolerably constant.
THE STEAM-ENGINE.
The steam-engine is a machine for utilizing the
heating-power of fuels, and, when complete, consists
MATTER, ETHER, AND MOTION 136
of furnace, boiler, and engine. The furnace transforms
the energy of the fuel and air into heat units in the
boiler, and the engine transforms this into the work of
whatever sort it may be applied to.
Evidently the efficiency of such an engine must
depend upon how large a proportion of the heat units
it utilizes compared with the heat units supplied to it.
Steam-engines permit the steam to escape into the air
generally with a temperature higher than boiling water,
and that means a great waste of unused heat; for the
steam in the engine loses temperature proportionate to
the work done by it, and, as stated before, the steam
pressure is proportionate to its absolute temperature, not
its temperature as indicated by common thermometers.
And the absolute temperature on Fahrenheit scale will
be found by adding 460 to the indicated temperature.
Suppose, then, an engine-boiler delivered steam to the
engine at 248 Fah. = 708 absolute, and on exit from
the cylinder it was 212 Fah. = 672 absolute, then the
proportionate amount of work done compared with the
whole supplied would be 708 􀀀 672
708
= 36
708
, or only about
five per cent of the heating-power of the fuel. Higher
efficiency must be looked for chiefly by using steam
at higher temperature and, therefore, higher pressure,
which would increase the value of the numerator.
HEAT 137
The efficiency of engines is generally given in the
amount of coal required to maintain one horse-power
per hour. A horse-power for an hour is equal to
3300060 = 1, 980000 foot-pounds; and the coal required
varies from about two pounds in the best engines
to six or eight pounds, locomotive engines generally
being less efficient. As one pound of coal when burnt
has an equivalent of 11, 194000 foot-pounds of work,
two pounds will give 22, 398000 foot-pounds. When
that maintains a horse-power for an hour, or 1, 980000
foot-pounds, the efficiency is 1, 980000
22, 398000
= 8 per cent.
This appears very low; but it is to be remembered
that the coal is seldom anywhere near pure; that much
heat escapes by the flues without heating the water;
that much is lost by heating the engine, boiler, and the
pipes, etc., that does no good, and most of that that
does go through the engine escapes to the air without
having done any work; and it cannot be helped, for
steam condenses to water at 212, and is no longer
able to do steam service. In reality, such an efficiency
is relatively high.
AS TO THE NATURE OF HEAT.
It has been pointed out that it was concluded
early in the century that heat must be some kind
MATTER, ETHER, AND MOTION 138
of motion, because its production depended solely
upon antecedent motion, and that later the quantitative
relationship between the two was accurately defined.
The nature of heat was ascertained, but the particular
kind of motion that gave it its characteristics was not
made out; that is, whether the motion was one of
free path of the molecules,—a swinging to and fro in
space,—or a true vibratory motion, such as a change
of form of the molecules and atoms that made up the
heated body, or a rotation of them, or a combination
of any or all of these, was unknown. At first the
conjecture prevailed that it was an oscillatory motion
of the molecules among themselves even in a solid
body; but after the discovery of spectrum analysis it
became apparent that the atoms and molecules were
in a state of true vibration, and their temperature
depended upon the amplitude of that vibration. If one
will remember that the atoms of matter are certainly
elastic, and are not solid, and will also picture to
himself what mechanically must happen when such a
body is struck in any manner, that it must vibrate,
for the same reason that any visible elastic body must
vibrate if struck, he will see quite clearly the condition
of things among elastic atoms that collide with each
other so many times per second.
That they do thus vibrate is proved by the spectrum
HEAT 139
of substances in the gaseous state where between
impacts they have time to vibrate a great number of
times per second. At ordinary temperatures and density
a gaseous molecule of hydrogen, having a mean free
path of about the two-hundred-and-fifty-thousandth of
an inch, and moving at the rate of 6000 feet per
second, will collide with its neighbors 17750 millions
of times per second, but its spectrum shows that it
makes 450 millions of millions of vibrations in the same
interval, so that in each interval between impacts it
would be able to make 450, 000000, 000000
17750, 000000
= 25352, more
than twenty-five thousand vibrations.
Now, imagine a number of bells suspended by cords
of equal length from the ceiling, but not so near as to
touch each other. Suppose each bell to have the same
musical pitch as every other one, and now let one
of the outer ones be pulled away from the rest and
forcibly swung back among them; presently every bell
among them would be set swinging by the impact of
others upon it, and each impact would cause each bell
to sound its own particular pitch, and the elasticity
of each individual one would maintain that vibration
in some degree until the next impact, when it would
be strengthened, and one would hear along with the
bumping of the bells the sound due to the pitch of
MATTER, ETHER, AND MOTION 140
the individual bells. Something very like this goes
on among the molecules of the gas. Their vibratory
movements we cannot hear, but with the spectroscope
they are detected and measured. Now, hot bodies
cool by radiation—the giving-off of just such waves
in the ether as we are describing,—and the fact that
such cooling molecules of a gas give out constant
wave-lengths, as is shown by their spectrum lines, is
proof that the vibrations that originate the waves are not
Diag. 7.
free-path or oscillatory motions, but
true atomic ones, due to a change
in form. How this can be is easily
seen by considering the change in
form made by any vibrating body,
say, a ring. Let the heavy lined ring
represent an elastic atom: if it be
subjected to impact it will assume
an elliptical outline, and go through
a series of phases represented by
the dotted lines. This change of form, and uniform
vibration, is a mechanical necessity, and is independent
of the size or particular form a body may have. It is this
kind of motion that embodies the energy represented
by the temperature of an atom or a molecule, and the
temperature varies with the square of the amplitude of
this motion; and two bodies have the same temperature
HEAT 141
when their molecules have the same vibratory energy. A
single molecule in free space would radiate all its heat
away, and thus be reduced to absolute zero, if it were
not continually receiving from other bodies an amount
that depended upon its nearness to them and their own
amplitude of similar motion. Hence the temperature of
a body depends upon the amplitude of vibration of its
molecules, and not upon any translatory or oscillatory
or rotatory motions. This is not saying that molecules
that are heated do not have other motions than the
vibratory ones constituting their temperature, but when
they do have others it is at the expense of the vibratory,
and therefore has reduced the temperature; and such
free-path motion as all gases have, and which produces
pressure upon the walls of vessels, is maintained by
the vibratory. It is not heat, but the result of heat, in
the same way as the translatory motion of a bullet is
not heat, but the result of heat. Most books on heat
do not make the distinction here made, but combine
the heat-motion of the molecules themselves with the
translatory motion they have, calling the sum of them
the heat of the gas. So long as one is concerned only
with the energy involved in the actions it will make
no difference; but if one analyzes the process for the
factors it is plain that there are two distinct kinds
of motion—one of them capable of setting up waves
MATTER, ETHER, AND MOTION 142
in the ether, the other not, for it is not known that
any free-path or translatory movement of a body ever
disturbs the ether; and if distinctions of such marked
characters as these exist, and one of them involves
temperature and ether waves, and the other does not,
they ought not both to be called by the same name.
The peculiar character of the energy involved in heat as
distinguished from so-called mechanical energy, is that
the factor of motion is of the vibratory sort, whereas
the other is more or less translatory,—one capable
of easy transformation into ether waves, the other
incapable of such transformation, but each of them
easily transformed into the other by impact. Equivalent
velocities give the same amount of working ability, or
Wv2
2g
= Wa2n2
2g
= Pd (see p. 82). So it can be understood
how ordinary visible motion can be transformed into
heat, and vice versa, as easily as one can understand
how the motion of the clapper of a bell is transformed
into sound.
ORIGIN OF THE SUN’S HEAT.
There has been much speculation as to the source
of the heat of the sun. Unless one assumes that it has
some miraculous or non-physical origin he is bound
HEAT 143
to account for it, if at all, upon the assumption that
physical conditions and relations, such as we find at
the earth, hold good at the sun as elsewhere.
At the beginning of this chapter the various sources
of heat were considered,—the mechanical, the chemical,
the electric, and the radiative. If these be tested as to
their sufficiency to account for the temperature of the
sun, one may reach a conclusion as to the probability
of any or all of them being concerned in it and their
relative importance.
It will be convenient to consider them in the reverse
order, and first as to radiations. In order that a body
should become heated by radiations, there must first
be some body or bodies having as high or higher
temperature to give rise to the radiations; and in this
case, if the sun’s heat came from such a source, one
would need to look for the other bodies in the universe
having such high temperature. The millions of stars
shining by their own light would at first seem to
furnish the proper source; for the testimony of the
spectroscope is that they all are highly heated, and
some astronomers think some of them to be much
hotter than the sun is. One of the conditions under
which radiant energy is distributed in space is that its
amount upon a given surface is inversely as the square
of the distance from the source; and as every one of
MATTER, ETHER, AND MOTION 144
these bodies is at such an amazing distance away, it
is only with the most delicate instruments that their
radiant energy can be measured, and a given surface
upon the earth would receive as much as the same
surface upon the sun, and the earth would be heated
from the same source as much as the sun would be.
Practically it is found to be but a very small quantity,
and hence radiation from other bodies cannot possibly
account for the sun’s heat.
Second, as to electrical currents: it may be said
at the outset we have no direct knowledge that there
are such at the sun, and from other knowledge we
have of its constitution it would appear to be highly
improbable that there were or could be electric currents
there. Electric currents imply some generator and some
conductor for their transference; and from what is
known or may fairly be inferred that every substance
we are acquainted with as a conductor of electricity
which is present in the sun—and there are a good
many of them—iron being particularly abundant, yet
they are all at such a high temperature as to be a far
reach from the conductibility we know anything about.
There may be, but it is by no means certain, something
solid in the sun, but the most of it is as gaseous as a
bubble, and gases do not conduct currents of electricity.
Third, chemical action is known to be the antecedent
HEAT 145
of vast quantities of heat. It may be recalled that
a pound of hydrogen, for instance, when allowed to
combine chemically with oxygen will give out 61000
heat units. The atmosphere of the sun appears to
be made up of elements mostly in an uncombined
form, except in the cooler, outlying parts; that is, the
temperature is so high that chemical combination is
impossible except in exposed places where radiation can
allow cooling to take place. It is tolerably certain that
chemical combinations are taking place there whenever
it is possible, and with such combination heat must
be produced, if physical laws are in operation there
as they are at the earth, but the amount of it going
on, or possible, if the whole body of the sun were to
combine its elements in this way, does not appear to
begin to be equal to the expenditure of heat actually
taking place.
There remains only the mechanical sources of impact,
friction, and condensation. There is good evidence that
there is a large body of meteors in the neighborhood of
the sun that must be falling upon its surface. The sun’s
attraction can give a velocity of nearly four hundred
miles a second to any body reaching him from distant
space, and such a velocity would, on impact, produce
heat enough to reduce the whole body to a gaseous
state almost instantly.
MATTER, ETHER, AND MOTION 146
Given the mass and velocity of a body, and one
may calculate how much energy it has, and how much
heat is the equivalent of the mechanical energy. Such
a computation shows that even if the earth were to
fall into the sun, it would be volatilized in a very
brief time. If the sun’s surface were solid the impact
would be sufficient to effect it almost instantly. If the
shell of the sun were liquid it would be changed more
slowly through friction, but, in the end, the result
would be the same. It does not appear, however, that
there is sufficient material that finds its way to the
sun to furnish but a small proportion of the sun’s
heat, so neither impact nor friction can be admitted as
sufficient agencies. There remains but one more, namely,
compression. Is there any evidence that condensation
is taking place? The body of the sun is 866000 miles
in diameter, and is so far away that this immense
magnitude occupies but about half a degree of arc. If
it were to shrink at the rate of a mile in twenty years,
it would account for the present rate of expenditure,
but such a shrinkage could not be observed from the
earth for several thousand years, for nothing much less
than a second of arc can be observed with certainty,
and a second of arc at the sun’s distance is equal to
about 465 miles, so it would require 465  20 = 9300
years to produce an observable effect.
HEAT 147
Now, if the nebula theory be true, the sun once
occupied all the space between itself and the outer
boundary of the solar system and has shrunk to its
present dimensions, a process which, if heat alone
were concerned, would require about eighteen millions
of years. It is not probable that heat alone has been
concerned, so it is probable that the sun is older than
that, but the shrinkage will account for the heat, and
it appears as the only probable conjecture. It will be
understood that the gravitative action is the occasion
of the compression, and that the approach is constant
and as fast as the generated heat can be radiated
away. It has been calculated that at the above rate of
condensation it may be reduced to one-half its present
diameter with its present radiation rate, in about five
million years, when its density will be about twice that
of water.
From such considerations it appears in a high
degree probable that the heat of the sun is due to
condensation, the condensation is due to gravitation,
and thus one is led back to a time when the substance
of the sun and all the planets was scattered through
that immense space, the diameter of which is not
less than six thousand millions of miles. How matter
came to be thus scattered is at present an enigma. It
is important to remark here, though, that until there
MATTER, ETHER, AND MOTION 148
was impact among atoms, and molecules were formed,
there evidently could be no such condition as what we
call heat, and until these atoms and molecules vibrated
there could be no light, that is, ether waves.
EFFECTS OF HEAT.
Once in possession of a good, mechanical conception
of the action going on in a heated body, one can proceed
to trace out the various effects of heat in all directions.
Thus to take the familiar one of pressure in a gas. A
gas is simply a large number of individual molecules
moving about with great velocity and bumping against
each other and the sides of the containing vessel.
Each molecule, though small, has some momentum;
but the enormous number of them in, say, a cubic
inch, five hundred millions of millions of millions, and
their relatively high translatory velocities,—say fifteen
hundred feet per second, gives them momentum which,
when spent upon the side of the vessel, gives a pressure
equal to about fifteen pounds per square inch. If
one were to hold up a shield against which many
balls were thrown per second, he would need to brace
himself to withstand the pressure that would appear
to be constant.
If the gas be heated the molecules have increased
HEAT 149
amplitude of vibration, and they rebound from each
other with greater velocity, and strike the side with
more momentum, and hence the pressure is greater. As
the pressure is proportional to the absolute temperature,
it is plain there could be no pressure if there was no
vibratory motion. If the density of the gas be increased
by adding more molecules per cubic inch, there must
a greater number of them strike upon the sides of the
vessel in a second, which will increase the pressure,
that is, the pressure varies as the density.
When it is said that gases have a tendency to
expand, or that they exhibit a repulsive action, all that
is signified is this; as elastic bodies, the molecules
rebound after impact, and continue on in their direction,
according to the first law of motion, until otherwise
obstructed. When a ball rebounds from the side of the
house it has been thrown against, it is not because
there is any repulsion between the ball and the house.
EFFECT OF PRESSURE UPON BOILING AND FUSION.
When it is said that the boiling-point of water
is 212, it is to be understood that the pressure of the
air upon the surface of the water is fifteen pounds
per square inch. At elevated places water boils at a
much lower temperature; and when in a tight vessel,
MATTER, ETHER, AND MOTION 150
like the boilers of steam-engines, the pressure of the
steam affects its boiling-point in the opposite way,
raising it. Thus at twenty pounds steam pressure, the
temperature required to boil water is 228, at sixty
pounds it is 291, at ninety pounds 319, and at the
high pressures employed in locomotives of one hundred
and fifty pounds or more to the square inch, the
temperature of the steam and water is 360 or more.
As one goes down into a mine the pressure of the
air becomes greater, and higher temperature is needed
to boil water. The explanation of this phenomenon is
that the heated molecules of the liquid are bumping
against each other in all directions, but the surface
molecules can receive such bumps only from below
and on their sides. If there were no molecules above
to beat downwards, the surface molecules would fly
rapidly up into the free space, which would be what
we call a vacuum. This escape of the surface molecules
of a liquid into the space above is called evaporation,
and the higher the temperature of the liquid the harder
the bumps, and the more will be flipped away from
the liquid and become free rovers, having a long,
free path. When, however, the gaseous particles are
numerous and strike back upon the surface, that is,
when there is a gaseous pressure upon the surface,
the surface molecules are prevented from rising, that
HEAT 151
is to say, evaporation cannot go on so fast, boiling is
prevented until more energy is given to the water, and
that means a higher temperature.
The melting-point of substances is likewise affected
by the pressure to which they are subject, and increasing
the pressure increases the temperature needed to fuse
them. Such small variations of pressure as only a few
pounds per square inch do not make much difference,
but pressure measured by tons per square inch makes
a great deal. The condition of the interior of the earth
appears to depend upon this as a most important factor.
As one goes beneath the surface of the earth in mines
and tunnels, it is observed that the temperature rises
about one degree for every fifty or sixty feet of descent;
and it was formerly inferred from this that at the depth
of a few miles a temperature would be reached high
enough to melt the most refractory bodies, and hence
the interior of the earth was probably in a fused state
while the crust was relatively thin. Such a view took
no account of the effect of pressure upon the state of
bodies. At the depth of a mile of water the pressure
must be equal to 62.55280 = 330000 pounds per square
foot, and as rock is 21
2 times the weight of water, the
pressure must be 825000 pounds, or over four hundred
tons; and at five, ten, or a hundred miles, it is obvious
the pressure is correspondingly greater. A body that at
MATTER, ETHER, AND MOTION 152
the surface of the earth would melt at any assignable
temperature would require a much higher temperature
to fuse when subjected to such enormous pressure.
It appears that the pressure increases faster than the
observed temperature; and hence the earth must be
solid to the centre, instead of being liquid as formerly
supposed. This makes it appear that the phenomena
of volcanoes are only local, and do not indicate any
general melted condition of the earth. If a body that
would melt at a thousand degrees on the surface of
the earth be subject to such pressure that it is not
melted when its temperature is two thousand degrees,
then, if the pressure be suddenly removed from it, the
heat it has will instantly liquefy it. This may be the
condition at the base of volcanoes, where shrinkage
of the earth’s crust in some direction may relieve the
pressure in some other direction; and a large mass
of heated material may become liquid, expanding in
volume, and overflow in any direction where there is
a vent, and this would be called a volcanic eruption.
MAXIMUM TEMPERATURE.
We have considered the condition called absolute
zero, wherein the molecules have no vibratory motion
whatever; and it has also been pointed out, and it is
HEAT 153
generally agreed, that the temperature of a body varies
as the square of its amplitude of molecular vibration.
It has often been assumed in treating of high
temperatures, such as that of the sun for instance, that
there is no limit to the temperature to which matter
can be raised. So some have estimated the temperature
of the sun to be several millions of degrees; but a
consideration of the factors involved will show such a
conclusion to be impossible, for the dimensions and
form of a body set a limit to the amplitude it can have.
A tuning-fork cannot have its prongs vibrate beyond
the limit where its prongs touch each other, and a
vibrating ring cannot have an amplitude greater than
one-fourth its circumference; and this degree is only
possible to a mathematical circle having no thickness.
Make a ring of a piece of twine, and elongate any
diameter until the opposite sides touch, then move the
middle points through a similar distance, and it will
be seen that the limit will be equal to a quadrant of
the circle; but if the ring be a thick one, say made of
rope, it would be less than that, and how much less
will depend upon the relative thickness of the rope
to the diameter of the ring. If the thickness of the
rope were one-fourth the diameter of the ring, then
the amplitude could be but one-half the quadrant, and
so on. Now, the atoms of matter have a definite size,
MATTER, ETHER, AND MOTION 154
and no one has ventured to suggest that they were
variable in size in any degree; and one may, therefore,
compute the greatest amplitude such a body could
have, whether it were a circle or a hollow sphere
without thickness. If the diameter be as before stated,
one fifty-millionth of an inch, calculation shows that
the greatest amplitude it could have would be about
one sixty-four-millionth of an inch. This, multiplied by
the number of vibrations it makes per second, will give
the equivalent velocity from which its energy can be
calculated. On page 79, it is shown that the velocity of
a vibrating atom, if the amplitude be one-half of the
diameter, will be about eighty miles a second. If the
amplitude be equal in measure to the quadrant, as is
here supposed, this velocity would be not far from a
hundred miles per second, and the energy represented
by that velocity would be the utmost energy of heat,
or highest temperature that the body could have. The
pressure of gases enables one to determine the velocity
of the particles; and when this is known at a given
temperature, the temperature at any other velocity may
be computed.
The statement that atoms and molecules can have
a maximum temperature must not be understood to
imply that the energy they can have is fixed at that
limit, because aside from their temperature energy,
HEAT 155
represented by their vibratory motion, they can have
any assignable translatory velocity in addition. But it
does imply that ether waves, arising from temperature,
have a fixed limit for each element; and such radiant
energy from a given source cannot be transmitted
beyond a certain rate, because its amplitude has a limit,
so that whatever actual energy the sun as a whole
may have, it cannot lose that energy by radiation faster
than an assignable rate.
This has an important bearing upon the question
of the age of the sun. Computations have been made
of the length of time the sun can have been giving
out its energy, on the assumption that the sun is a
cooling body, and that it was formerly much hotter
than it is now. If the above statements are correct,
the probability is that the sun is as hot now as it
ever was, and that its rate of loss of heat by radiation
has not been greatly different from what it is to-day;
so, instead of being only fifteen or twenty millions of
years old, it may be very much more.
As the temperature of a body represents its molecular
energy, and is measured by mv2
2
, it follows that if two
different kinds of molecules, such as hydrogen and
oxygen, have the same temperature, they will have the
same amount of energy; but the mass of an oxygen
MATTER, ETHER, AND MOTION 156
molecule is sixteen times greater than the mass of a
hydrogen molecule. In an equal weight of the two
there will be sixteen times more molecules of hydrogen
than of oxygen, and therefore the hydrogen will have
sixteen times the energy of the oxygen at the same
temperature. To produce a rise of temperature of one
degree in a pound, or any given weight of hydrogen,
would require sixteen times as much heat as the same
weight of oxygen would need. This difference in
thermal capacity of different substances is called their
specific heat. In general, the lighter the molecules that
make up a substance, the more numerous must they
be to make up a given mass, and the higher will be
its specific heat; i.e., the more heat must be expended
upon it to produce a given rise in its temperature. The
specific heat of water is chosen as a standard and is
unity, as it is found to require more heat to raise a
given weight of it one degree than any other substance.
One heat unit will raise the temperature of a pound
of it one degree; all other substances require but a
fraction of this. From what is said, it appears that the
specific heat of an element varies inversely as its atomic
weight. The specific heat of a substance determines
the temperature it will attain when a definite quantity
of heat is supplied to it. If a pound of hydrogen and
eight pounds of oxygen are exploded together, and not
HEAT 157
allowed to expand in volume, 51444 heat units calories
are produced. The 51444 heat units would be divided
among nine pounds of water vapor, that has a specific
heat under such conditions of .37. The temperature
attained would be 51444
9  .37
= 15450. This temperature
is much higher than the limit of possible combination
of the two gases, which, at about 3000, are unable to
combine, so such an action could not take place any
faster than the parts could cool down to the latter
temperature. If the mixture be allowed to expand,
the temperature of 3000 may not be reached, and the
action of the whole is so rapid it is called an explosion.
DISSOCIATION.
When compound molecules are broken up into their
elementary constituents in any manner, the process is
called dissociation. It may be effected by electrical
action, as when water is decomposed by it, or by
chemical action, as when wood is decomposed under
water, setting the carbon free; but heat is competent to
effect the same end. At the temperature of about 3000
the existence of water is impossible, as the elements
cannot stay united, and the reason is obvious. Whatever
the nature of the attraction that holds atoms together
in chemical compounds, if the elementary atoms are
MATTER, ETHER, AND MOTION 158
themselves in brisk vibratory motion, as we know they
are, they must be straining their bonds continually
to separate; and when the amplitude of such motion
reaches a certain maximum, the impacts are so violent
as to make the atoms rebound out of each other’s
neighborhood, and thus prevent cohesion. The atoms
then either enter into new combinations with others, if
possible, and if not they remain as gaseous particles,
and subject to the laws of gases.
If one starts with a piece of ice and applies heat it
melts, and we call the liquid water. Apply more heat
and the water becomes steam, in which the individual
molecules are no longer able to cohere, because of
their energetic motions; but each molecule remains
intact, having a long free path, for a cubic inch of
water becomes nearly a cubic foot of steam under
ordinary air pressure. If still more heat be applied, the
molecules become more and more unstable until they
too are broken up in the same way and for the same
reason that the solid and the liquid forms were. When
it is no longer possible for hydrogen and oxygen to
combine, it is still possible for the atoms of each to
combine with each other, hydrogen with hydrogen and
oxygen with oxygen, forming elementary molecules H
H, and O O; but if a still higher temperature be applied,
even this combination becomes impossible, and the
HEAT 159
atoms themselves become free rovers and individually
independent. Thus it is seen that the different states
of matter depend altogether upon temperature. At
absolute zero there can be no such thing as a gas, for
the molecules would have no individual vibrations and
therefore no free paths. They would probably fall to
the bottom of the vessel and remain quiescent. It is
also probable that both liquids and solids too would
cease to exist, not that matter would be annihilated,
but a solid, a liquid, and a gas are simply each
a bundle of physical properties that depend mostly
upon temperature, and those properties would probably
disappear with the disappearance of the conditions
upon which they depended.
MATTER, ETHER, AND MOTION 160
CHAPTER VII
Ether Waves
It has already been stated in what has preceded this
that translational motions of matter are not competent
to originate ether waves, and that vibratory motions
of both atoms and molecules can originate them. A
consideration of the origin, transmission, and effects
of such ether waves constitutes the subject-matter of
what is called the science of light. The word “light” is
commonly used to signify that agency in nature which
is capable of affecting the eye and causes vision, or
the sensation of sight, and until within a very few
years has been supposed to be a peculiar kind of a
wave motion in the ether quite distinct from other
waves known to exist which were competent to produce
heating and chemical effects, so such waves as were
known from their effects were called heat waves, light
waves, and actinic or chemical waves, according as
they heated bodies, produced light, or brought about
chemical reactions. These three sorts of waves were
supposed to coexist generally, but were capable of being
separated from each other so there could be a beam
ETHER WAVES 161
of either without the others. This is now known to be
a mistaken view, for what a given ether wave will do
depends upon what it falls on rather than on its own
peculiarity. The same waves that fall upon the eye and
produce the sensation of sight will heat other kinds of
matter, and if they fall upon a surface of molecules that
are unstable, that is, in which the atoms that make up
the molecules are not strongly cohesive, the molecules
are disrupted by the waves, and the atoms enter into
new combinations, and this process is called a chemical
process; and while it is true that some waves will not
produce vision, there are none that will not produce
both heating and chemical effects, so there is no such
distinction among ether waves as was supposed, and
this leads to another conclusion also; viz., if there is
no such distinction between waves, then there is no
such thing as light at all, unless we classify all rays as
light, whether they can produce sight or not, which is
sometimes done to save explanations, but it leads to
the anomaly that there is such a thing as dark light,
which is absurd. There will be no difficulty whatever
if light be defined as a sensation merely, and the
waves competent to produce the sensation be called
visual waves. Up to the present time, however, the old
terminology is quite generally adhered to in spite of
the difficulty of reconciling the old signification with
MATTER, ETHER, AND MOTION 162
the new knowledge. There is no single word that
signifies ether waves in general, and independent of
the effects that may be produced in specific cases, and
for that reason this term has been adopted. The word
“light” is entirely inadequate, and likely to mislead
one not well versed in the phenomena.
ORIGIN OF ETHER WAVES.
The source of ether waves of all degrees whatever
is the vibratory motions of atoms and molecules
as distinguished from their translatory, or free-path
motions, but their rates of vibration are determined
by their atomic weights. An atom of hydrogen, for
instance, has a different rate from oxygen, for the same
reason that two tuning-forks, though made precisely
alike, would have different rates if one were made of
steel and the other of aluminium. If they have different
rates, then the number of waves produced by them
per second will be different, and as all waves travel in
the ether with the same speed, namely, 186000 miles
per second, the length of the waves produced by them
must be different.
There are about seventy different elementary atoms,
each setting up its characteristic waves in the ether all
the time. It is to be remembered that all atoms and
ETHER WAVES 163
molecules are always to be considered as hot bodies;
that is, bodies having some temperature, and mostly
a long way above absolute zero; and also that their
energy of this kind may be spent upon the ether. If
the waves from one molecule have more energy than
those given off by a second molecule upon which they
fall, the second one absorbs some of it so as to have
its own temperature raised until it is the same as
the other; that is, until the energy given off by them
both is equal. And this is universally true. Matter
is continually exchanging energy in this way, always
tending to bring about equality of temperature. But
the number of vibrations a body makes does not need
to be the same as that of another body in order to
possess the same amount of energy, for the energy
depends upon both mass and velocity. If the mass be
small, the velocity must be greater, and vice versa. And
thus it is that the seventy elements that make up the
kinds of matter we know are everywhere and at all
times setting up ether waves, each kind its particular
rates, when not otherwise interfered with.
There is, however, a qualification that must be
added that has a high degree of scientific importance.
Every elementary substance is vibrating at several rates
at the same time, as do piano-strings, bells, and
musical instruments in general. Every particular rate
MATTER, ETHER, AND MOTION 164
of vibration produces its own waves, and thus each
atom and molecule is continually producing, when not
interfered with, its own characteristic set of waves. This
must make the ether waves from the different kinds of
matter exceedingly complex, and disentangling them
correspondingly difficult; yet it has been done.
When we look at luminous bodies, like the sun or
stars, or flames, or gas, they seem to differ from each
other in brightness and sometimes in color, as is seen
in fireworks. A flame of alcohol has a bluish tint, a
little salt in it makes it yellow, some lithium makes
it red, and copper, green or bluish, while sunlight is
white, as is the electric light. If one looks through a
common prism at the landscape the edges of objects
appear in rainbow tints, and with the colors arranged
in the same order, while at the same time the shape of
things is more or less distorted. If a beam of sunlight
be sent directly through such a prism, a patch of colors
may be seen on the floor or wall, and this is called a
solar spectrum; and if this light of different tints has
its wave length measured, it appears that the red light
has a wave length of about the one forty-thousandth
of an inch, and the violet light at the other extreme a
wave length of about the one sixty-thousandth of an
inch, while the intermediate tints range regularly from
the one to the other. There is in this spectrum that
ETHER WAVES 165
can be seen an almost infinite number of wave lengths;
there is no break among them apparently. The same
Diag. 8.—Visible Solar Spectrum.
thing holds true of a spectrum produced by letting
the light from a lamp or candle go through the same
prism: the tints, their order, and their wave lengths are
found to be the same. The prism then receives ether
waves of any or all wave lengths, and separates or
disperses them in the order of their wave lengths. In
doing this it deflects the longer waves less than it does
the shorter ones. The deflection of the waves from their
original course is called refraction, and the separation
from each other so as to produce the spectrum is called
dispersion. A prism effects both at the same time, and
thus enables one to isolate at will any particular tint or
part of the spectrum; and if one takes a single narrow
portion in any such spectrum, he has a bundle of
light rays of uniform wave lengths, and he may then
determine their value. In this way the wave lengths of
the different colored parts of the spectrum of sunlight
have been found to be as follows:—
MATTER, ETHER, AND MOTION 166
Red, about 39000 to the inch
Orange, „ 41000 „ „ „
Yellow, „ 44000 „ „ „
Green, „ 47000 „ „ „
Blue, „ 51000 „ „ „
Indigo, „ 54000 „ „ „
Violet, „ 57000 „ „ „
Extreme visible, about 60000 „ „ „
A spectroscope is an instrument composed of a
prism mounted between two tubes, one of them having
an adjustable slot for the light to be examined to
pass through on its way to the prism, the other being
a short telescope to magnify somewhat the image of
the spectrum that it may the better be seen. With
this, light from any source may be examined. Light
made up of all wave lengths that can be seen shows
as a complete spectrum, while any light made up of
but a part of these gives a corresponding incomplete
spectrum. The flame of an alcohol lamp, or a Bunsen
gas-flame, gives but little brightness and not much to
produce a spectrum; but a little salt in the flame gives
to it a bright yellow tint, and shows in the spectroscope
a single narrow band of yellow light in the same
place as the yellow seen in sunlight, and therefore
having the same wave length. Such a beam made up
of waves of one wave length is called homogeneous
light. This sodium light has a wave length of about
ETHER WAVES 167
Diag. 9.—Spectroscope.
the one forty-four-thousandth of an inch. With other
more refined methods, which cannot be described here,
sodium is found to have other wave lengths beyond
both the red and blue ends, and which cannot be
detected by the eye alone. Hydrogen, another element,
gives a bright red line and a blue line that are easily
seen; and several others may be detected with more
delicate apparatus. In this manner all the elements
have been attentively studied during the past thirty
years, and many treatises may be found that give full
particulars of the processes and results. The substance
of knowledge obtained by the study of the spectra of
MATTER, ETHER, AND MOTION 168
the elements may be briefly stated to be,—
1st, Each element has its own vibratory rates at
a given temperature, and sets up corresponding ether
waves; some of these can be seen, and others require
more complicated apparatus to discover.
2d, In order that the characteristic vibrations of any
atoms or molecules may take place, it is necessary that
they be allowed a free path to vibrate in; in other
words, they need be in the gaseous state. If they be
crowded together, as they are in solids and liquids,
they have no chance to vibrate without interference. A
pailful of school-bells might make a jangling noise, but
would give no particular pitch or characteristic sound
of any of the bells, and only when not interfered
with for a part of the time at least could one give
out its true sound. This gaseous state is generally
obtained by igniting in flames or by the electric spark
the substance to be examined. In an electric arc all
substances are volatilized, and may be then studied
with the spectroscope to great advantage. Sometimes
substances that remain in the gaseous state at ordinary
temperatures, such as hydrogen, oxygen, chlorine, etc.,
are hermetically sealed in glass tubes, after rarefication,
in order to obtain long free paths, and are lighted up
by means of electric discharges through them.
3d, On account of the lack of vibratory freedom,
ETHER WAVES 169
the molecules of solids and liquids give out vibrations
of all wave lengths, for every partial and incompleted
movement disturbs the ether; and there are all degrees
of these, but the energy of the shorter ones is rarely
great enough to affect the eye, and hence are not visible
at ordinary temperatures. If a body like a cannon-ball
be gradually heated in the dark, it will presently begin
to glow with a dim red tint. If looked at through the
spectroscope, only red light on the extreme red border
can be seen. As the temperature rises, additional
shorter waves appear, and the spectrum broadens to the
orange, then the yellow, and so on; the ones already
showing growing brighter meanwhile, until the ball is
in a bright glow, and a full continuous spectrum is
produced. As the ball cools, the reverse holds true;
and the violet waves are the first to disappear, then
the blue, and lastly the red vanishes from sight. Still
the ball is much too hot to safely touch, and continues
to cool by giving off ether waves differing from the
rest only in being too long to affect the eye. They still
are refracted by the prism, and an invisible spectrum
is produced, and this spectrum has been traced out to
ten times the length of the visible spectrum.
The sun, an electric arc, and other solid hot bodies,
give out similar long, invisible spectra.
In like manner, where the body is white-hot, and
MATTER, ETHER, AND MOTION 170
Diag. 10.—Complete Solar Spectrum.
giving out the shortest waves the eye can see, there
can still be found, a long way beyond that limit, waves
that can do photographic work, which is but a kind
of molecular dissociation.
4th, Where waves of a given length are made to
pass through a gas having similar vibratory rates, or
capable of producing waves of the same length, the
molecules of the latter will absorb such waves, and
therefore stop their progress, especially if they have
more energy than the waves the absorbing gas can give
out. So if sunlight containing the same yellow light
as that of sodium gas be made to pass through the
latter, it will be stopped; and if this be done where
there is a spectrum of sunlight, the yellow will be cut
out from it, and there will be but a black line instead.
This is called gaseous absorption, and is an illustration
of what was said a little way back about the exchange
of energy always going on. The absorbing power of a
gas has a significance like its radiations, and indicates
its presence as well.
ETHER WAVES 171
The yellow light of sodium gas has a definite place
in the spectrum; and hence if one perceives those wave
lengths in a gaseous spectrum, he knows that sodium
must be present in a state of incandescence, giving
rise to the waves. But if the light from a white-hot
cannon-ball were to be sent through that same vapor,
and afterwards examined with a prism, the yellow light
would be absent, and the absence would still proclaim
the existence of sodium vapor.
Hence, if an incandescent body gives a continuous
spectrum, it must be a solid or a liquid; the molecules
must be so compact that the individual vibrations are
prevented, and only irregular ones can be made. If a
discontinuous but bright line spectrum is shown, the
matter must be in a gaseous state, and the molecules
have free path.
If a bright spectrum have black spaces or bands
across it, there is indicated a solid or liquid incandescent
body shining through gas that acts by absorption upon
it, and thus both the solid and gaseous conditions are
detected, as well as the nature of the substance in the
gaseous state.
This knowledge has been applied to the discovery
of the substance and condition of the sun and other
celestial bodies, and it is concluded that the sun has a
solid or liquid surface as a shell to a gaseous interior,
MATTER, ETHER, AND MOTION 172
and that the atmosphere of it consists of the various
elements that make up the body of the sun in so highly
heated a condition as to keep them in a vaporous or
gaseous state. The characteristic spectroscopic lines of
about forty elements have been found there. Some of
the elements have a very large number of spectroscopic
lines. Iron, for instance, has several hundred lines.
Hydrogen is particularly abundant. Perhaps the most
important discovery due to the spectroscope has been
this: that there are a very large number of gaseous
bodies, called nebulæ, in the heavens; some of these
fill immense spaces; they are in a condensing state,
and all of them are mostly made up of hydrogen.
This discovery gave an additional probability to the
nebula theory of the origin of the solar system, for
it showed that process in its various stages in more
distant parts of space: and in addition to that, it has
led to the surmise that in some way some of those
we now call elements are really compounds of more
elementary substances, probably hydrogen; but that is
a speculation merely, for there is no other than such
spectroscopic evidence that anything like transmutation
of what we call elements into others can take place.
The spectroscopic examination of the other members
of the solar system has shown that Mars has an
atmosphere like ours, holding watery vapor in it; that
ETHER WAVES 173
Jupiter is red-hot; that the temperature of Saturn is
probably much too high for any such living things as
exist on this earth—and in this way has answered the
question so interesting to most thoughtful persons as
to whether the planets are inhabited or not. Jupiter
certainly cannot be inhabited by any such beings as
we are, for the temperature would destroy all organic
things.
Velocities of translation can also be measured when
as high as two miles a second or more, by the
displacement of spectroscopic lines towards one or the
other end of the spectrum. If a star is approaching
us, the wave lengths are shortened a small quantity,
and that changes the position of a line towards the
blue end, while recession makes it longer and moves it
towards the red end, so it has been found that Sirius
is receding at the rate of nineteen miles per second;
that Arcturus is coming towards us at the rate of sixty
miles per second. In like manner is shown that the
sun, and with him the whole solar system, is travelling
in the direction of the constellation Hercules at the
probable rate of about sixteen miles per second.
Now, all this presupposes that the principles
established in the laboratory for substances there
investigated are applicable wherever such matter exists;
for instance, that the spectrum of sodium and of
MATTER, ETHER, AND MOTION 174
hydrogen and iron, which depends upon temperature
and pressure, is as reliable if the light comes from a
body a million miles or a thousand million miles away
as if it came from only one mile or a foot distant. If
it be thus widely applicable, then do we have the best
of testimony that matter, its conditions, and its laws
are the same everywhere, and that the earth is a fair
specimen of the rest of the universe.
OTHER PHENOMENA OF ETHER WAVES.
Whenever a line of ether waves—which is generally
called a ray, whatever the wave length may be—falls
upon matter, the ray may be either absorbed, transmitted,
or reflected. Neither of these results takes place singly
in any case. There is no known body, for instance, that
can wholly absorb all the rays that fall upon it, nor
wholly transmit or reflect them. If a body should be
able to absorb all the rays that fall upon it, we should
not be able to see it unless itself were a self-luminous
body, for we only see other than self-luminous objects
by means of the light reflected from them, and such a
body would reflect no light, and hence could not be
visible.
Bodies which absorb most of the rays that fall upon
them we call black and opaque; that is, a body that
ETHER WAVES 175
reflects but a small portion of the waves that are incident
upon it is a dark or black body, because we see but
little of it. If it reflected none at all, it would be quite
invisible. In like manner, a perfectly transparent body
would be one that would neither absorb nor reflect any
rays, and for that reason would be quite as invisible
as space itself. The air is perhaps as near an approach
to perfect transparency as anything that can be named;
yet if it reflected no rays at all, there would be nothing
of the diffused light that is now so plentiful on the
clearest day, but there would be only what would come
direct to us from the sun or other luminous body. We
call clear glass and water transparent because objects
can be plainly seen through them; and a sheet of hard
black rubber we call opaque, for nothing whatever can
be seen through it, nevertheless it has been shown
that waves longer than those that affect the eye, go
through such hard rubber as easily as the shorter ones
we call light go through glass, hence transparency and
opacity are terms only relative to particular kinds of
waves. All kinds of matter reflect more or less of the
waves that fall upon it. This reflection is merely the
change in direction of the ray; but it always follows a
definite law, keeping to its original plane, and making
the angle of reflection equal to the incident angle.
The surfaces of most bodies are very rough, and the
MATTER, ETHER, AND MOTION 176
rays are reflected in all directions, because the points
upon the surface face in so many ways. This will
be obvious to one who looks at the surface of paper
or of wood with a magnifying-glass. The smoother a
surface is made, the nearer will all the incident rays
take the same direction on reflection. Mirrors are thus
made of smooth glass or metallic surfaces, and are
plane, convex, or concave; but whether they are made
with plane or curved surface, the rays reflected always
follow the above law.
REFRACTION.
So long as ether waves fall perpendicularly upon
any surface of any kind of matter, the rays go straight
on into it if they be not reflected or absorbed at the
surface; there is no change in the direction, but the
velocity of transmission is less in all kinds of matter
than it is in the ether. In glass it is only about
two-thirds as fast, and in water about three-fourths.
When the ray meets the surface at an angle, it is bent
out of its course more or less, depending upon the kind
of material it falls upon, and also the angle at which
it meets it. This change of direction, when entering a
new medium, is called refraction, and this property is
possessed by all kinds of matter, solid as well as liquid
ETHER WAVES 177
and gas. The refraction for a given angle of incidence
is more for a liquid than for a gas, more for a solid
like glass than for water or other liquids, and more
for a diamond than for any other known substance.
The same rule that obtains when the waves enter a
medium, holds when it leaves it; the direction it will
now take will depend upon the angle the rays make
with that surface and the character of the medium
into which it enters. Thus, if a ray meets a piece of
plain glass at an angle, say, of 45, some of it will
be reflected, making an angle of 90 with the incident
ray, and some of it will be refracted into it, making
an angle with the original direction, and continue on
in a straight line until it meets the next surface, when
it will again assume its original direction: but when
the second surface is not parallel with the first, as
is the case with the prism, the direction may depart
still more from the original; and the shorter the wave
length, the more the deflection. It is this property
that is made use of in spectroscopes, microscopes, and
telescopes. A lens has one or both surfaces curved, so
as to be convex or concave, depending upon the use
it is to be put to,—a convex glass converging the rays,
and a concave one separating them,—and almost any
degree of either of these may be obtained by proper
curvature.
MATTER, ETHER, AND MOTION 178
Both microscopes and telescopes are so common, and
descriptions of them are to be found in so many places,
that they need not be described here. The inquiry is
often made, why still more powerful microscopes and
telescopes are not made so as to reveal the very smallest
and the most distant thing. The utility of a microscope
depends upon how plainly it is able to make minute
objects visible; and the more a given one magnifies an
object, the smaller the portion that can be seen and the
less light is available for the purpose, and when the
objects are so small as the few thousandths of an inch,
the light waves interfere with each other at the edges,
and produce colored fringes that cannot be got rid of
altogether, and very small objects become indistinct for
that reason. Microscope lenses are marked as 1 inch,
1
2
inch, 1
10
inch, and so on, meaning by the fraction
the approximate distance it must be brought to the
object in order that the latter may be seen. The higher
the power, the shorter this distance. A one-tenth inch
objective may magnify an object a thousand diameters
and perhaps more, so that a blood corpuscle having a
diameter of only one three-thousandth of an inch may
appear about three-tenths of an inch in diameter, and
the details of its coarser structure may be very well seen;
but if there be a minute point upon it, still indistinct
ETHER WAVES 179
because it is minute, and a still greater magnifying
power required to see it, and a 1
20
objective be taken,
the actual magnifying power may be five thousand
diameters. But now one is approaching the dimensions
of wave lengths themselves, and the agent necessary for
observing introduces its own complications, producing
distortions and color fringes about the point to be
studied, and no way has been found of obviating this.
Objectives have been made having a focal length of
only the 1
50
of an inch and one having only the 1
75
,
but no work of any importance has ever been done
with them. The best of the microscopic work has
been done with lenses that magnify no more than one
thousand diameters. It is said that the best microscopes
will show an object that is no more than about the
one hundred-thousandth of an inch in diameter, but it
appears simply as a point or a line, and no details
of its structure can be seen. Fine rulings upon glass
have been made that are known to have this degree of
fineness, because the mechanism that rules them can
be gauged to that degree; but many persons cannot see
these in a microscope, though others can. So within
the limits of the visible not a little depends upon the
acuteness of vision, and there is a great difference
among individuals in this respect. On account of
MATTER, ETHER, AND MOTION 180
the properties of the ether waves themselves in their
relations to each other, it does not appear probable that
much improvement is possible to the microscope. This
does not imply that we may not know more of the
minute structure of bodies than we do now, for there
are other sources of knowledge of minute quantities
than simply direct eyesight, which are just as reliable,
perhaps more so. A good chemical balance will weigh
to the millionth part of the load. Whitworth showed
that it was possible to measure to the millionth of
an inch by touch. The spectroscope will indicate the
millionth of a grain by the tint of the gas flame, and
the color of a drop of water is appreciably changed by
the one three-millionth of a grain of fuschine. Some
substances, like essential oils, sulphuretted hydrogen,
and the odors of flowers, can be perceived when the
quantity is certainly less than the fifty-millionth of a
grain.
Any day may bring tidings of new instrumentalities
that help in the solutions of the interesting questions
concerning molecular structure that are now quite out
of our reach. Let it be granted that the problems are
altogether physical ones, such as are justified by the
known mechanical relations of energy, and one may
wait with patience. Let one assume that some or any of
them are not mechanical, and he not only is in danger
ETHER WAVES 181
of having to revise his judgment in some degree any
day, but he reasons against the significance of all the
knowledge we have of matter and its energy.
The larger a lens is the more light can go through
it: a lens two feet in diameter will let four times as
much light through it as one only one foot in diameter.
As remote objects, like the distant stars, appear dim
on account of their great distance, it becomes needful
to concentrate the light from a much larger area than
that of the pupil of the eye. If the pupil be one-tenth
of an inch in diameter, a certain amount of light from
a star may enter it. A lens one inch in diameter would
concentrate at its focus 100 times as much, and one
a foot in diameter, 14400 times more; and hence the
object would appear so much brighter. Along with
this apparent brightening of the star, it is apparently
brought nearer and enlarged. There are limits to the
size and useful magnifying power of telescopes as well
as to those of microscopes. The magnifying power of
telescopes depends very largely upon the eye-pieces
used, and the shorter their focal length the more do
they magnify. The large lens, called the objective,
serves mostly to collect a large amount of light. It is
to be kept in mind that the movements of bodies are
magnified as much as their apparent dimensions, and
when there are any movements of the body surveyed,
MATTER, ETHER, AND MOTION 182
or of the instrument itself, distinct vision becomes
correspondingly difficult.
With the telescope the chief trouble comes from
movements of the air, which are rarely of uniform
quality and motions. Not only its transparency, but
its degrees of density caused by heat and wind, are
varying all the time; and these seriously interfere with
telescopic work. If a magnifying power of say 100
be employed, these disturbing causes are increased in
proportion, and with a power of 1000 nothing can be
distinctly seen. Suppose, however, the air be in best
condition for observations, and a power of 1000 be put
upon the moon. As the moon is about 240000 miles
away, this magnifying power would have the effect of
bringing it 1000 times nearer, or as it would appear to
the eye if it were but 240 miles away. Now, an object
240 miles away can reveal no interesting details at all;
anything much less than half a mile square could not
be distinguished unless it were a very bright or very
dark spot. Powers as high as 8000 have been used; and
such a one would bring the surface of the moon as
it would appear if it were about thirty miles distant,
which might show a city, a large town, a lake, and
the difference between field and woodland, yet nothing
satisfactory was seen for the reasons mentioned, so for
most astronomical work a magnifying power of only a
ETHER WAVES 183
few hundred is used; seldom more than five hundred.
When large telescopes are set on elevated places like
the Lick Telescope on Mt. Hamilton in California, some
of the troubles from disturbed air are obviated, and it
is hoped something more may be learned about our
nearer astronomic neighbors. But these large telescopes
collect so much more light that stars so distant as to
be quite invisible with smaller glasses become plainly
visible with them. With the unaided eye no more than
5000 or 6000 stars can be seen in the whole heavens,
with an opera-glass as many as 100000 become visible,
while the Lick telescope, with an object-glass three feet
in diameter, shows nearly 100, 000000. Each increase in
the size of the telescope adds to the number of visible
stars, and one cannot but wonder if their number be
infinite, or if there be a boundary to the universe of
matter. Though the visible boundary of our universe
has been greatly extended by the invention of the
telescope, nothing has been descried anywhere but
matter and motion: there has been nothing added to
our knowledge but the sense of bigness. Instead of
only a few thousand of hot and flaming stars, there are
hundreds of millions of them, made of the same kinds
of matter, having the same kinds of motions, controlled
by the same laws, and nothing animate in any of
them more than in a bowlder in the wall. Clifford
MATTER, ETHER, AND MOTION 184
said he wished they were farther off. The problems of
astronomy are interesting studies in mechanics, but are
not inviting to those most interested in life and mind.
Herschel and Chalmers and Dick and Mitchell are dead.
The knowledge already gained has destroyed both their
arguments and hopes, and has left the inhabitants of
this earth the possessors of the universe, yet unable to
take possession.
If there are inhabitants in Mars they are as unable
to traverse space as we are; and the possibility of our
yet being able to do that is not half so unlikely as
it seemed to be but a very few years ago, since it
evidently requires for accomplishment but a directed
reaction against the ether; and we already know how
to produce the reaction by electrical means; and every
point in space has the energy for transformation.
It is generally agreed that the so-called attraction of
a magnet for its armature is really due to the pressure
of the ether upon the latter, and it may be as great as
two hundred pounds to the square inch.
An electro-magnet without an armature is therefore
reacted upon by the ether to that degree. When this
reaction can in any way be neutralized at one pole
and not at the other, the ether reaction will push the
magnet backwards, and the navigation of space will at
once become mechanically possible.
ETHER WAVES 185
THE RADIOMETER.
It is a familiar enough fact that when sunshine falls
upon a surface the latter becomes heated. In general,
the darker the color of the surface the more rapidly
Diag. 12.—Radiometer.
does the temperature rise; and
some bodies, when thus exposed
for some time, become unbearably
hot. We are able to say that the
surface molecules of such a body
are in a brisk vibratory movement;
that they have more energy than
other bodies with less temperature.
If one imagines the condition of
things when the molecules of the
air impinge upon such a heated
surface, he will understand how
they must bound away from it
with greater velocity than they
struck it with, and if with greater
velocity, then with greater energy.
As action and reaction are equal, it
must kick back upon the surface as
it leaves it, thus tending to make
the surface move in the opposite
direction; and a large number of
MATTER, ETHER, AND MOTION 186
such impacts must give a resultant backward pressure.
If the surface be a small one, the increased pressure in
the air in front will travel round to the other side at
the rate of eleven hundred feet in a second in ordinary
air; so the pressure will be equalized in a very short
interval of time. If the air be rarefied in front of
such surface to such a degree that the free path of
the molecule is many times greater than its ordinary
length, that pressure cannot get round nearly so fast,
and there will consequently be a constant backward
pressure, produced by the molecules that impinge upon
it and become heated by contact with it. The pressure
per square inch is very slight, as it is produced by a
relatively small number of molecules; but it may be
made apparent by mounting some disks, blackened on
one side, upon a pivot in a glass bulb, and, after
exhausting a large part of the air, hermetically sealing
the bulb. Such a device is called a radiometer. When
put where sunshine, or the light from the flame of a
lamp or candle, or even the heat of the hand, may
fall upon it, the vanes begin to rotate, the blackened
side backing away from the source of the energy.
This movement was at first interpreted as being due
to the actual pressure produced by light waves, but
further investigation showed that idea to be wrong.
The movement comes from the transformation of the
ETHER WAVES 187
motions of ether waves, first into heat, and second into
the translational mass motion observed. The radiometer
is, therefore, a machine for transforming ether waves
into visible mechanical motions.
PHOTOGRAPHY.
It has already been explained how heat acts upon
molecules, increasing the amplitude of the vibrations
of the atoms that make them up, and, if carried to a
sufficient degree, is able to quite destroy the molecular
structure and enable the component atoms to enter
into new combinations. The degree needed for this
depends upon the kind of molecules. Some molecules
are so stable that only the very highest temperature we
can produce can break them up. Others are so feebly
cohesive that the least touch will cause them to go to
pieces, and sometimes with explosive violence, as is the
case with what are called fulminates, compounds of
nitrogen with silver or with mercury; and sometimes the
same result is reached by ether waves, whose number
per second is such as to set one of the ingredients
into sympathetic vibration and thus decompose the
compound, doing it at a slower rate than the others.
Nearly all complex molecules are decomposable in this
way, and the process is going on all the time in nature
MATTER, ETHER, AND MOTION 188
where there are organic things to act upon, but the
process is usually slow.
When shingles are first laid they have a fresh surface
and new appearance, which is presently lost by the
exposure. Take a freshly planed piece of soft pine or
other white wood, and fasten to the surface a piece
of paper cut into any shape or design,—a circle, a
star, or the like,—and set the wood where the sun
can shine on it for a few days. When the design is
removed the figure will be plainly seen on the wood
by the difference in tint between its surface and that
part which the sun has shone upon. The latter is much
darker. This is an example of photographic action, as
is the color of fruit, etc.; for if a design is pasted upon
a green apple, which is red when ripe, the design will
protect the surface from the action of the light, and
will therefore appear upon the apple in a light tint.
Diagrams and letters may be fixed thus upon fruit of
any kind. Discolorations of all sorts, due to ether waves
or light, may properly be called photographic action,
both fading and darkening, as when the skin becomes
tanned. For practical purposes some compounds of
silver are generally employed, because they are more
sensitive to the action of visible waves than most other
substances. They have the property of being easily
disorganized by waves whose length ranges from about
ETHER WAVES 189
one forty-five-thousandth of an inch to those in the
neighborhood of the seventy-thousandth of an inch,
some of these being visible waves, the others being too
short for visibility. When a surface is prepared with
some one of the sensitive salts of silver,—generally the
iodide or the bromide,—and a picture of an object
produced by the lenses of the camera is allowed to
fall upon it, the decomposing action is proportional to
the amount of light and shade in the different parts;
and, when the plate thus exposed is placed in certain
chemical solutions called developers, the decomposition
is completed and the products dissolved out, leaving a
coating of pure silver, with a thickness proportional to
the chemical action that has taken place. This gives,
then, a correct likeness of the picture that was in the
camera. Formerly it took a long time to produce such
a picture, a person having to sit still for half an hour
or more. More and more sensitive preparations were
produced, until now a good picture can be taken in
less than the thousandth of a second; and the practice
of the art has become a great industry. There are
many preparations in common use for taking such
pictures, but nearly all of them have silver for the chief
constituent. It may be remarked that silver compounds
are remarkably unstable. Silver is not easily oxydized,
for it remains untarnished for an indefinite time, as
MATTER, ETHER, AND MOTION 190
exemplified by coins and jewelry. But there are plenty
of other compounds that may be used. Thus the
common blue-print is a compound of iron. The salts
of chromium are also sensitive to such waves.
It was remarked that the salts of silver are sensitive
to ether waves between quite a wide range in wave
lengths, but the longest of them is in about the middle
of the visible spectrum. They reach from there into
the region beyond the violet. Yellow and red waves
are incapable of affecting such a preparation, while the
waves that are the most efficient for it are the blue
ones.
Diag. 13.—Photographic Range for Silver Salts.
Other substances have a different range, and a curious
chemical discovery has shown that silver molecules
may be loaded; that is, may have attached to them
in a temporary way some other kinds of molecules
that render them sensitive to waves of any length. If
an ordinary photographic plate has a solar spectrum
ETHER WAVES 191
thrown upon it, there will be no indication of action
below the green; but, if aniline be added to the sensitive
coating and the plate be then exposed in the same
way, the action will now be seen to have gone on to
a distance below even the longest red wave that can
be seen. In this way photography has shown that the
spectrum of most incandescent bodies is much longer
than the visible part of it in both directions. It was
the observation that photographic action took place
most strongly in the blue part of the solar spectrum,
and in the region beyond, that led to the belief that
light waves and chemical rays were, in some way,
unlike each other. From what has been said it will
be seen that the reason for the different action was
due to the character of the material used. When a
molecule is made bigger or heavier in any way, longer
waves can affect it more; and that is the significance
of the so-called loaded molecule. In reality, the whole
molecule is made more complex and bigger, and longer
waves can shake its atoms loose.
It is to be hoped that all can understand that there
is nothing mysterious about photographic action; that
it is as simple in its mechanical principles as anything
can be. One may not be able at once to say in any
given case which atoms or which parts of a molecule
are loosened by the vibratory strains. In this one it
MATTER, ETHER, AND MOTION 192
may be the nitrogen, in another it may be the silver,
and in still a third it may be oxygen; but in each case
the mode of action is the same, and it may be said to
be mechanical throughout.
VISION.
Our various senses differ much in their mode of
action, and require for excitation not only each its
proper stimulant, but degrees of remoteness from actual
contact to the most distant points. Thus the sense of
touch requires absolute contact of a body: so also does
taste,—the sugar or the salt must dissolve upon the
tongue. A distance of but the tenth of an inch between
the sugar and the tongue will be absolutely prohibitive
to the consciousness of sweetness. The sense of smell
requires the actual contact of the gaseous molecules
upon the nasal membrane, but currents of air and
gaseous diffusion secure to us this condition, so that
the emanating body itself may be at some distance, and
yet we become conscious of the bank of violets, the
cup of coffee, or the chemical laboratory. This sense,
therefore, enlarges our field, so to speak, and permits
us to be conscious of bodies out of our immediate
reach. The sense of sound still farther enlarges the
space that can react upon us. But the loudest sounds,
ETHER WAVES 193
such as the roar of cannon and thunder, lose their
intensity shortly, and can rarely be heard beyond a
few miles. If our endowment of senses stopped with
these, we should really be quite limited in our possible
knowledge; for as we can know only what comes into
our experience, how small the possibilities of existence
would be to us! What we could touch, taste, smell,
and hear we could know something about, though we
were unconscious of any lacking sense. We should
need some apparatus that could make us conscious of
the most distant things as well as those close at hand.
We should need just what we have got,—the sense
of sight, that extends the field of experience and of
interest to us to the boundaries of creation. The other
senses give us information of contiguous things, but
sight brings the universe itself to our consciousness.
The sense of touch is diffused all over our bodies.
There is no such thing as an organ of touch. The
senses of taste and smell are restricted to localities and
to organs that have other functions as well. Only sound
and sight have specific organs, having no other function
than to respond to sonorous and optical motions, and
thus they have a peculiar dignity in the physiological
mechanism; and precisely because the eye and ear
have these mechanical functions do they come into the
domain of physics. They are machines by which certain
MATTER, ETHER, AND MOTION 194
forms of motion are transformed into others suitable
for nerve transmission to the seat of consciousness.
It has often been pointed out that the structure of
the eye is like the camera of the photographer. In
each there is a chamber a, having a lens in front,
which has a length of focus adapted to the distance
Diag. 14.
between it and the back of the chamber, so that the
image of objects external to it will be produced by
it upon the back of the chamber, where there is in
each a sensitive coating so affected by the light as
to make an impress. In the camera this action has
been explained as chemical reaction when molecular
dissociation results, proportionate to the amount of
light that falls upon any part of the surface exposed.
In each there is an arrangement for altering the focal
distance of the lens. In the camera it is a ratchet-wheel
that moves the lens towards or away from the back.
ETHER WAVES 195
In the eye there are muscles attached to the edge of
the lens that by contracting make the pliable lens less
convex and so increase its focal length. For the camera
Diag. 15.—Photographic Camera.
there is an exchangeable
diaphragm having
perforations of various
sizes to admit more or
less light through the
lens. In the eye there
is a colored muscular
disk called the iris, that
contracts or expands in
an automatic way so as
to expose more or less
of the lens to the light.
The functions of the two
devices are identical.
The energy possessed
by the ether waves that fall upon the sensitive
photographic plate is spent in doing the molecular
work of disintegration. In the eye all the energy is
stopped at the sensitive back coating called the retina,
and must of course be accounted for in some physical
way. In the camera all the energy of the waves is spent
in precisely the same kind of a way; that is, there is no
such distinction as what is called color in it: and color
MATTER, ETHER, AND MOTION 196
Diag. 16.
photography—that is, the direct picture of objects in
their proper, natural tints, such as we know they have,
upon the sensitive plate—has not been accomplished,
for the probable reason that the colors of the molecules
that are the result of the decomposition of the silver
compound are either transparent or blueish black. In
the eye, the distinction between wave lengths which
we denominate color sensation is very pronounced.
The sensations are so much complicated with the
processes that induce them that it is not always easy to
keep in mind the purely physical side or the subjective
side while treating of them.
ETHER WAVES 197
The following are some of the more common
phenomena of vision which must be taken into account
in forming any judgment or theory of it.
When a firebrand is swung round and round it
leaves an apparent luminous trail, the length of which
depends upon the rapidity of motion. This is called the
persistence of vision, and indicates that the sensation
does not cease instantly after the source has gone. If
the brand be swung round at the uniform rate of once
per second, the length of this luminous trail will be a
rough measure of the duration of the sensation after it
is once excited. Thus, if it appeared to be one-quarter
of the circle, the sensation must last for one-fourth a
second. For impressions not very bright the sensation
lasts but about the tenth of a second. If, however, the
object looked at be very bright, like the sun, for an
instant, the sensation may last for many seconds; and,
in general, the older the person the longer does it last.
Different colors also have different degrees of
persistence. Violet, blue, and green soonest fade out,
and red is the last to vanish for most eyes. This
signifies that wave length has in someway to do with
the persistence. When a bright colored object, like a
bit of red paper, is put upon a sheet of white paper
and steadily looked at for a few seconds, and is then
suddenly removed while the eyes are kept fixed upon
MATTER, ETHER, AND MOTION 198
the same place, the image of the red paper will still
be seen, but it will appear with a green tint, and will
fade out in a few seconds. A green piece of paper,
or any green object looked at in the same manner,
will give an image in red. Blue ones give yellow,
and yellow blue; and these tints seen in this way are
called complementary to each other, as it is found by
combining such together they produce the sensation
of white light. Whiteness is therefore a compound
sensation. Formerly, it was thought that white was
only produced by the composition of all the colors of
the spectrum in the same proportions they exist in it;
but the same sensation of whiteness can be produced
by red, green, and violet, and by blue and yellow. This
is not to be understood as applying to pigments or
paints, but to light itself.
If one looks at a strongly lighted object intently for
a few seconds, and then turns his eyes to a dimly
lighted drab surface, he will be able to see, sometimes
in a surprisingly realistic way, the same object against
the new background. If it be a person looked at,
the features may even appear in a startling way. The
size of the subjective figure will depend upon the
distance of the background, being larger the more
remote that is. Age and health have much to do with
the persistence of such sensations. Young and vigorous
ETHER WAVES 199
persons seldom notice them until they carefully look
for them; while older ones, and especially weakened
ones, may be much troubled by them. Some nervous
systems react upon the eye itself, and give rise to
similar images there; and these subjective images have
not unfrequently been mistaken for objective persons
living or dead. The color a given object appears to
have is not unfrequently modified by what colors the
eye has been resting upon the instant before, and hence
two persons may look at once upon the same picture
and see it in very different tints.
As ether waves are the source of the sensation, it
is obvious that a certain number of consecutive waves
must be necessary to affect the eye; that is to say,
it is not in the least probable that a single wave of
any length could produce a sensation. How many are
needed is not known, but one can determine somewhere
near what the number must be if he knows how brief
a time is sufficient to produce a sensation. It is said
that some flashes of lightning have been found to occur
in less than a millionth of a second, and those may
produce a very strong sensation.
If there are five hundred million million vibrations
per second, as we know there must be to give such a
sensation, in the millionth of a second there must be
five hundred millions; if the brightness were reduced
MATTER, ETHER, AND MOTION 200
ten thousand times and it were still visible, there must
then have been not less than fifty thousand waves: and
this is equivalent to saying that the eye could perceive
light if it lasted no longer than the ten thousand
millionth part of a second, which is probably true. But
there is another condition; namely, the energy of the
waves must be sufficient to effect a physical change in
the eye; and we know that the energy of such ether
waves varies with the square of their amplitude. If,
then, any wave whatever has not energy sufficient to
produce the necessary physical disturbance in the eye,
it could not produce vision. And this is the most
probable reason that we do not see in what we now
call darkness. It has been shown that all matter at all
temperatures is vibrating and setting up ether waves,
and also that in all liquids as well as solid bodies
there are vibrations due to their atomic and molecular
interference; and, theoretically, there must be vibrations
of all wave lengths at all times and in all places, but at
low temperatures the shorter waves, though not absent,
would have but small energy, and, as the body becomes
hot and the shorter ones acquire more, it is done at the
expense of the energy of the longer ones, for the light
given out by an incandescent lamp increases faster than
the supply of energy to produce it. It therefore appears
as a necessary conclusion that the reason we cannot
ETHER WAVES 201
see in the dark is not so much because the waves of
proper wave length are entirely absent, as that they
have too little energy to affect our eyes. Other animals,
such as rats, mice, owls, bats, and the like, can see
where it appears to us to be pitch dark. They must,
therefore, have eyes adapted for longer wave lengths
than are ours, or else the sensitiveness of their eyes
exceeds ours. As they see readily in the daylight, it
is certain they are adapted to such waves as our eyes
are; and, if ours were sufficiently sensitive, or had a
greater range in effective wave lengths, there would
be no such condition as darkness. That is the same
as saying that darkness is in us rather than being a
condition external to us.
THE THEORY OF VISION.
When it was discovered that the sensation of whiteness
could be produced by combining three different colors,—
red, green, and violet,—it was inferred that there were
probably three sets of nerves that were spread as a
fine net-work over the retina so that either of these
rays might fall at any point in the field of vision
upon it and so produce the sensation. At the same
time, when one or two of them were absent, the
other nerve ingredient would be present to be affected;
MATTER, ETHER, AND MOTION 202
and, furthermore, each one of these three nerves was
sensitive to quite a wide range of wave lengths, and
their overlappings gave perception without any break
from the extreme red to the extreme violet. In this
way color perception could be explained. This view
was adopted as a working hypothesis; and there was
no other proposed, although there was no evidence
whatever for the existence of three sets of nerves
having different properties. It has, however, lately been
discovered that the retina secretes a substance called
purpurine, on account of its purple tint, which is very
rapidly bleached or decomposed by the action of light.
That is to say, it possesses photographic properties in a
marked degree. This discovery has led to the view that
vision may be altogether due to photographic action,
and the older view has been about abandoned. The
details of this theory have not yet been all worked out,
but the purport of it may be briefly stated.
Given the purpurine spread over the retina: this
would be its sensitive coating corresponding to the
silver preparation upon the photographic plate. The
action of the light upon it being the same in character,
decomposes it into simpler molecular compounds. The
optic nerve is certainly spread over the retina, and the
purpurine is in its meshes, and any disturbance taking
place in this substance must correspondingly affect the
ETHER WAVES 203
ends of the nerves imbedded in it. Given the disturbance
that can affect the optic nerves, and it is transmitted
at once to the base of the brain and there interpreted
as light sensation. The differences there might be in
the amount of disturbance would be the differences
that are called brightness or intensity. If molecules are
disintegrated, as in photographic action, there must be
a relatively large amount of free-path motion resulting
from the wave action in the eye, and the amount of
it proportional to the energy expended. Such an effect
would give a general sensation of light, probably, also,
effects of light and shade, so the forms of bodies would
be readily enough seen. It would also account for
persistent effects; for, when molecules are made to move
fast or slow, they do not cease instantly on the removal
of the source of the motion, but they continue to thus
move until their energy has been reduced to that of
the surrounding medium. With simple purpurine there
appears to be no more possibility of chromatic effects
than there is in the common silver preparation on the
photographic plate. Suppose, however, the purpurine
to be not a simple kind of a body, or made up of
only a single kind of molecules, but instead made up
of as many as three different kinds having as many
different molecular weights, and, therefore, capable of
being reacted upon by three different wave lengths.
MATTER, ETHER, AND MOTION 204
Call these three substances a, b, and c purpurine. Let
a be such as red waves can decompose, b such as
green ones can decompose, and c such as only the
short purple ones can break up or shake up. If these
are uniformly mixed together and spread over the eye,
then red waves would shake up the red constituent,
but would leave the others alone; and the same would
hold true of the others. If one has been looking at
red-light wave lengths, the a purpurine would be used
up, but the b and c would still be present unimpaired;
and now, when white light is again looked at, the
b and c would be acted on strongly because they are
present in greater quantity. The resulting sensation
would be the compound of these two reactions, which,
as is well known, is a greenish tint. In a like manner,
each of the others when used up would leave the same
field fresh with the other constituents, and so give the
complementary tints; and in this way chromatic effects
of all sorts can be accounted for.
Some persons are color-blind; that is, they are
unable to distinguish some colors; and this defect is
usually for red rays. Such a color-blind person will be
unable to see the red end of the spectrum, and the
colors of it will appear to leave off in the yellow or
orange. The old explanation was that the red sensation
nerves were absent. The newer explanation is that the
ETHER WAVES 205
a ingredient of the purpurine is wanting either partially
or altogether.
Of course it is to be understood that the products
of decomposition by light in the eye are removed and
fresh material secreted in its place by the organ itself
in a manner similar to the removal of waste tissue and
its repair in any other part of the system.
The function of the retina, then, would appear to
be the secretion of the sensitive substance needed for
vision, instead of itself being the sensitive substance.
Such an explanation of vision makes the eye still
more like the photographic camera than appears in its
outward form and mechanical functions. And thus one
is able to trace the forms of motion that constitute the
heat and the temperature of a body through its resultant
ether waves to the molecular break-ups at the ends
of nerve fibres, whence the characteristic motions are
transmitted to the base of the brain, to be interpreted
thus or thus, according to position, number, and energy.
We begin with motion, we end with motion at the seat
of consciousness, and there we stop. It is vibratory in
the hot body it starts from, it is undulatory motion in
the ether, it is oscillatory in the disrupted molecules,
and a longitudinal wave in the nerve. Whether it is
discharged from further service at the base of the brain,
or is stored up in some way as experience, no one
MATTER, ETHER, AND MOTION 206
can say; but it is certain that a relatively large amount
of molecular energy finds its way constantly to the
brain, and some of it is re-employed as reflex action,
giving rise to voluntary and involuntary muscular and
secretory processes, as when one winks, or dodges a
threatening motion before the will can act, or laughs or
weeps at sights and sounds. In either case the result is
the physical expression of a physical antecedent, with
an intermediate mental quality called emotion.
The eye may then be said to be a machine for
the transformation of ether waves into interpretable
molecular or atomic motions, and its function ceases
at the ends of the optic nerve.
ELECTRICITY 207
CHAPTER VIII
Electricity
The industrial applications of electricity are now
so extensive and varied that every one is acquainted
with them in some measure, and yet fifteen years ago
there were millions of persons in the civilized nations
who had never seen an electrical phenomenon with
the exception of lightning. The apparently capricious
behavior of lightning, together with the attractions
and repulsions exhibited by electrified bodies, were
phenomena so different in character from any other,
that it came to be looked upon as a very mysterious
force. Fifty and more years ago it was classed with
heat and light as one of the imponderables. To-day
even the question is often asked, What is electricity?
with the emphasis on the word “is,” as if one knowing
enough might describe it as he might describe a genii
or an object having specific qualities that might be
isolated from everything else. Some have thought it to
be a fluid, some two fluids, some vibratory molecular
motion, some a property of matter, some a motion
in the ether, some the ether itself; and, lastly, some
MATTER, ETHER, AND MOTION 208
have concluded that we do not and never can know
its nature. Hence, to-day there is no generally received
notion concerning its nature.
Still, one may know a great deal about the agent
itself,—how it originates, what it will do, and its
relations to other phenomena,—and not concern himself
at all as to the nature of it. Heat and many of its
laws were well known before any one knew or even
suspected what its nature was. The law of gravitation
is known and applied on the scale of the universe
without demanding any explanation of the phenomena,
and it is equally true that our knowledge of electricity
is very extensive and accurate, and doubtless what we
do not know to-day we may know to-morrow.
ORIGIN OF ELECTRICITY.
It is here to be assumed as known, that various
instruments, such as electrometers and galvanometers,
are employed to detect the presence of electricity, and
descriptions of them will not be given. Attention will
be paid chiefly to the conditions that are present when
electricity is generated.
ELECTRICITY 209
1. THERMAL ORIGIN.
When two different metals, such for instance as
copper and iron, are touched together, they are found to
be electrified; that is, an electrometer shows the presence
of electricity. A piece of copper wire twisted to a piece
of iron wire always becomes thus affected, but the effect
is so slight that only delicate and sensitive apparatus
will detect it. Wires of any of the metals under similar
circumstances exhibit the same phenomenon, but in
different degrees. This electrification is but transient;
in a few seconds it has vanished. If the junction of
the metals is heated by the fingers, or in any other
way, the electrical condition is maintained indefinitely.
If one will imagine such a compound wire bent into a
ring so the ends nearly touch each other, it could be
shown that the ends attract each other, the attraction
being but slight. Here we are not so much concerned
about the measure of what is taking place as with its
character. If the ends of the wires be allowed to touch,
and the twisted junction be kept warm, a current of
electricity will continue to circulate through the ring;
and, if the ends be connected to a galvanometer of
sufficient delicacy, the needle would be continuously
deflected, so long as the junction was warmer than
the outer ends of the wires; and the deflection of the
MATTER, ETHER, AND MOTION 210
needle would be found to vary with the difference
in temperature between the inner and outer junctions.
Some metals, such as bismuth and antimony, when
fastened by solder, or in any other way, give much
stronger effects with a given temperature at their
junction. Such a combination is called a thermo-electric
pair. By joining a number of such together, so that
alternate ends may be heated at once, the electrical
effect is increased proportionally: two will give twice,
and ten ten times as much, and so on. When a number
of these are nicely compacted together and provided
with binding-screws, they are called thermo-electric
piles, and are of service in some investigations. It is
not necessary, however, to have two different metals in
contact to obtain the same kind of effects. If a piece
of soft iron or platinum wire be wound into a close
coil about a lead-pencil and the ends of it connected
to a galvanometer, a current of electricity will traverse
the circuit when one end of the coil is heated in a
flame. If the other end be heated, the current will
go in the opposite direction. The twisting of the wire
into the coil produces a strain among the molecules
that changes the physical properties to a slight extent:
the density is altered. It therefore appears that in this
case, as in the cases with two different substances, we
have two physically different bodies, though of the same
ELECTRICITY 211
element. The facts may be generalized by saying that,
Diag. 17.—Thermopile.
whenever two differently
constituted bodies
are placed in contact
with each other,
electricity is generated,
and is maintained
so long as
there is a difference in
temperature between
the junction and the
external ends.
If one inquires for
the origin of such
manifestation as the
first case, when two
different metals are
placed in contact, attention
must be directed
to the actual
molecular condition of the two metals. Suppose them
to have the same temperature,—as they have different
atomic weights their vibratory rates cannot be the
same,—and when the surfaces are put in contact there
must be a re-adjustment of their molecular motions,
for each will interfere with the other. This disturbance
MATTER, ETHER, AND MOTION 212
of molecular rates is a disturbance in their relations
of energy, and furnishes the energy for the electrical
phenomenon that ensues. When equilibrium is restored,
as it may be shortly, there is no longer any electrical
exhibit.
When heat is applied so as to keep the junction
continually hotter than the other parts, the first effect
is continuous; for as each element has its own proper
vibratory molecular rate, which is increased by the
heat, the interference is kept up and an electrical
current results, which the heat is spent to produce and
maintain. One needs to have in mind what is signified
by heat as vibratory atomic, and molecular motion,
in order to clearly perceive what is expended in the
thermo-electric pile. The face of the pile, when it is
generating a current of electricity, does not acquire that
temperature it would acquire if it was prevented from
producing a current by having the wires detached.
Hence the amplitude of vibrations is lessened by the
electrical work done, and we may say that heat has
been converted into electricity, a thermal origin.
2. CHEMICAL ORIGIN.
When a piece of copper is dipped into a vessel of
water, and a wire leading from it is connected to a
ELECTRICITY 213
proper electrometer, it is found to be electrified to a
certain degree. If a piece of zinc be substituted for the
copper, it too indicates a still greater degree; and now
let both be placed in the same water and connected by
a wire, and a current of electricity will flow through the
wire, as in the case with the thermopile. This current
will be a transient one, or very slight, if the water be
pure; but if a little acid like sulphuric be added to the
water, the current may be relatively a strong one. If,
Diag. 18.
Galvanic Cell.
instead of the zinc and copper, any
other two metals be taken, the results
will differ from the former only in
degree. Zinc and copper, or zinc and
carbon, are generally employed, because
those have been found to give better
results than other available elements;
and such a combination of metals, with
some solution, acid or alkaline, which
is capable of dissolving one or both of
the metals, is called a galvanic battery.
A single jar with its proper elements is called a cell;
and by the addition of cells additional effects may be
produced; that is, with two cells twice, and with ten
cells ten times the effect.
As with the thermo-pair, one may inquire what
conditions were known to be present that could furnish
MATTER, ETHER, AND MOTION 214
an antecedent to the electrical current that results.
This is answered by pointing out, as in the other
case, that there are two substances differing in their
physical qualities, copper and water, or zinc and water,
and molecular rearrangement at their junction must
necessarily result. More than this. It is known that
the zinc and oxygen have a strong affinity for each
other. The oxygen is combined with hydrogen to form
the water, and in water the molecules are without any
definite arrangement: they face in all directions, and
move about with the greatest freedom, with but little,
if any friction. When zinc is placed in it, the attraction
of the zinc for the oxygen part of the molecule must
result in making every water molecule in proximity to
the zinc swing round so as to present its oxygen side
to it. This orientation of the liquid molecules is called
their polarization. The attraction between the two is not
quite strong enough to disrupt the water molecule; but
the addition of sulphuric acid weakens the attraction
between the hydrogen and oxygen, and enables the
oxygen to seize a zinc atom, and both combine with
the sulphuric acid to form the sulphate of zinc. Here
we have chemical reactions such as always result in
exchange of energy; for the sulphate of zinc has less
molecular energy than the zinc, the water, and the acid,
in the same way that carbonic acid gas has less energy
ELECTRICITY 215
than the carbon and oxygen gas that formed it. There
has been, then, a molecular change accompanied by the
development, first of heat and second the generation of
electricity; for if the electrical current be not allowed
to flow, the battery cell will itself heat up more than
it otherwise would do. There are chemical, thermal,
mechanical, and electrical phenomena here, which may
be perceived by carefully thinking of the successive
steps in the process. The distinctive thing here is to
bear in mind what the characteristic antecedents of the
electrical phenomena are. What are the chemical, the
thermal, the mechanical factors, except special forms
of exchangeable molecular motions? So one may say
that in a galvanic battery chemism or heat has been
transformed into electricity. Though the mechanism of
transformation is different, yet the same factors appear
as in the thermopile.
3. MECHANICAL ORIGIN.
When a piece of glass or of wax is rubbed with
a cloth or catskin, the two substances subject to the
friction become endowed with a new property which
they do not otherwise exhibit. If a glass disk be
mounted so as to be rotated, and proper connections
made to it, as in the common Static Electrical machine, a
MATTER, ETHER, AND MOTION 216
Diag. 19.—Static Electrical Machine.
current of electricity may be maintained by maintaining
the friction, and all the electrical phenomena may be
produced that can be with electricity from any other
source. They are identical, but the source is the
friction of dissimilar substances. It will be recalled that
dissimilarity in substance was the condition in each of
the former cases; but in this, mechanical friction is the
second factor. In the chapter on heat it was pointed out,
and it is a familiar enough fact everywhere, that heat
ELECTRICITY 217
is always the immediate result of friction. So in this
mechanical source, with apparatus so dissimilar in all
outward form to both thermopile and galvanic battery,
we still have precisely the same molecular conditions
that were operative in them to produce electricity,—two
dissimilar substances, and heat or a kind of motion
that results at once in heat.
4. MAGNETIC ORIGIN.
If a wire of any sort be placed across the pole of a
magnet, and held quiet there, no electrical effect will be
noted; but if the wire be moved toward or away from
the pole, it will become electrified, and if one end of it
be connected to an electrometer the movement of the
needle will indicate it. If the two ends of the wire be
connected to a galvanometer, whenever the wire is thus
moved in front of the magnet pole a current will flow
through the circuit, and the movement of the needle
this way or that will indicate the motion of approach
or recession. The strength of this current will vary with
the rapidity of the motion of translation of the wire
through the space in front of the magnet; and the wire
through which it goes becomes heated. This is the same
as saying that the mechanical motion of translation of
the wire is converted into heat in a manner as if it had
MATTER, ETHER, AND MOTION 218
been subject to ordinary friction there; and as a matter
of fact, it is found to require more energy to move
the wire in such a space when the ends of the wire
are in contact, than it does when they are not. This
shows that the material of the wire is subject to some
restraint under such conditions and in such positions,
and the degree of restraint depends upon the distance
it is from the magnet, as well as upon the strength
of the magnet itself. Hence the different parts of the
wire are in different physical states. And this is just
what is exhibited by the twisted wire in the case of
the thermal origin; and when motion is imparted to
the wire, the degrees of stress in it change, and a
current of electricity is the result. That such a stress
is really present in the wire can be proved in several
ways, which only need to be alluded to in this place.
First, the electrical resistance of a wire is greater when
in front of a magnet than elsewhere; and second, the
phenomenon known as Hall’s, in which a current of
electricity going through a conductor is deflected from
its course in the neighborhood of a magnet. So we
have, in this magnetic origin, two bodies with different
physical constitutions and external motions impressed
upon them, which gives the electrical product observed.
ELECTRICITY 219
5. ELECTRICAL ORIGIN.
Imagine two wires parallel to each other and a foot
apart. If an electrical current from any source is made
to traverse one of them, a corresponding current will
be initiated in the other, but in the contrary direction.
In a like manner if a constant current be kept in one
of the wires, and the other one be moved towards
and away from the other, currents will be set up
in it. Their direction will depend upon whether the
motion be approach or recession. The effect is the
same whether either or both move at the same time.
The effect is similar to the one described under the
head of Magnetic Origin, showing that in some way
the space about a wire having a current of electricity
in it is substantially similar to that about a magnet.
The process is called electro-magnetic induction in both
cases, and the explanation is the same in this as in
the other. It will be well, however, to point out that
there are steps in this process that need attention for
the sake of mechanical clearness.
Given say, an electro-magnet, through which a
current can be sent at will, and so be made magnetic,
and with the wire in front of it as before. There
is now no magnetism and no electricity in the wire.
Make the iron magnetic, and the current is at once
MATTER, ETHER, AND MOTION 220
induced in the other. I say at once, but this does
not mean instantaneously. It takes a short time for
the effect of the magnet upon the ether to travel to
the wire and affect it. As no electricity escapes from
the electro-magnetic circuit, the electricity observed in
the wire, or second circuit, is generated in it, and
the immediate antecedent of it was the stress in the
ether which was produced by the magnet. Hence an
electrical current can arise from a proper kind of stress
in the ether, no matter how that is produced, as one
of the factors; the other factor being motion of some
sort, mechanical or otherwise. The steps are, an electric
current in a conductor, an electro-magnetic effect of the
current upon the ether, the reaction of the ether upon
the second conductor. Let these steps be kept in mind
always when thinking about inductive action, and there
can then be no confusion from trying to imagine how
electricity gets from one circuit to another when they
are insulated from each other.
6. PHYSIOLOGICAL ORIGIN.
There are certain kinds of fish that are capable of
giving powerful electrical shocks to men and animals.
They are provided with special organs for this purpose,
but they have not been the subject of much study for
ELECTRICITY 221
several good reasons. First, they are only to be found in
a few localities, and are difficult to obtain; and second,
their electrical qualities cannot be studied except when
they are alive; and when they are living and healthy
their shocks can kill both men and animals, and few
are willing to incur the risk. Both mankind and animals
in general can give rise to electrical currents. By
grasping with the thumb and finger of both hands the
terminal wires from a delicate galvanometer, a current
is indicated,—a part often due to thermo-electric action,
and a part to physiological action,—and it will vary with
the tightness of the squeeze of contact and the person
experimenting, some developing much more relatively
than others. It also varies with the parts of the body
in contact with the wires. This physiological effect is
always extremely minute, and is not to be mentioned
beside the amount necessary to effect the remarkable
things said to be done by personal electricity, such as
moving chairs, tables, etc. I do not think any one has
been found whose physiological electricity could do so
much as raise a grain the tenth of an inch.
The various processes continually going on in the
body, such as breathing, digestion, blood-circulation,
and muscular motions of all sorts, and under conditions
of different temperatures, different material, different
chemical reactions, are quite sufficient to account for
MATTER, ETHER, AND MOTION 222
all that has been observed in this direction.
7. ATMOSPHERIC ORIGIN.
The origin of lightning, so far as details go, has
never been satisfactorily accounted for. It is obviously
not an affair that can be investigated in any very
scientific manner, for one can never control any of the
conditions when it arises.
Some have thought it due to the condensation of
electrified vapor molecules condensing into drops of
water, the degree of electrification increasing with the
size of the drops. How the original electrification of
the molecules was produced is not explained by such.
There is no doubt but that a large amount of energy
is often involved in a stroke of lightning, judged by its
sudden destructive work. The immediate source of this
energy is the question. There is no doubt but when a
gas or a vapor is condensed into a liquid, a notable
amount of energy is liberated in motions of some sort;
for it requires energy to be spent upon water to produce
the vapor. This is given back when the process is
reversed. This energy has often been called latent heat.
If this process goes on faster than it can be conducted
away, it must either be transformed, or the process
must stop. We know, too, that heat motions are most
ELECTRICITY 223
freely transformed into electrical by the phenomena of
the thermopile and the galvanic battery, and it is not
improbable that this is the source of the atmospheric
electricity. It is certain that where it originates there
are two differently constituted kinds of matter,—the
air and the water; and it is equally certain that there
are some vigorous exchanges of motion, both in the
form of wind and heat, and these are the conditions
present in each of the cases where our knowledge is
most complete.
One may then fairly conclude from the analysis of
all the known sources of electrical development, that
motion of some sort is the antecedent in every case.
This motion may be the sort called mechanical, or that
called molecular or atomic, as heat, but it is always a
factor; and the amount of electrical energy developed
in every case is equal to the immediate mechanical,
chemical, or thermal energy which disappears when it
is produced. If one admits that the quantity of energy
in phenomena is constant, that the quantity of matter
is constant, there is but one variable factor, and that
is motion. If mechanical motion is transformable into
heat, and heat into electricity, and some known form of
motion is the invariable antecedent to the production
of electricity, it does not need a very profound logician
to say, so far, the nature of electricity is known.
MATTER, ETHER, AND MOTION 224
ELECTRICAL TERMINOLOGY.
Every particular science and art has some technical
terms to give precision and definiteness to its processes
and its laws, and the advances made in any science
depend very largely upon exact signification of its
terms. The late rapid development of electrical science
is due in a large measure to terminology, adopted
about twenty-five years ago; for it enables a man not
only to know what he himself is talking about, but also
to understand others, and that was not the case before.
A system of units and names for them are matters of
the first importance. How these were derived need not
be stated here, but it is needful for every one now
to understand the significance of the more common of
them.
Imagine a wire in front of you with an electrical
current traversing it from left to right. If it travels in
that direction it is because the electrical pressure is
less towards the right than in the opposite direction,
just as water flowing through a pipe towards the right
travels thus because gravitative pressure is less in that
direction than in the other. Gravitative pressure is
measured in pounds, electrical pressure is measured in
volts.
If the pressure at the left of the wire were increased
ELECTRICITY 225
in any way, there would be an increased current of
electricity in the wire, just as there would be more
water go through the pipe if the head or gravitative
pressure were increased. The rate of water flow might
be measured as so many cubic inches or cubic feet
per second. The rate of electrical flow is measured in
amp`eres.
If the water pipe were a large one, and the pressure
the same, more water would flow through it than if it
were a small pipe of the same length. In like manner a
thick wire will permit more electricity to flow through
it with a given electrical pressure than a thin one. The
water pipe is said to oppose friction to the movement
of water.
A conductor of electricity is said to offer resistance
to the flow of electricity. No name has been given to
any unit of frictional resistance, but electrical resistance
is measured in ohms.
A definite quantity of water flowing at a given rate
will be emptied from the pipe in a second or a minute.
So will a definite quantity of electricity go through the
wire in a second or a minute. The quantity of water
thus flowing would be measured as so many cubic
feet, or so many gallons; the quantity of electricity is
measured in coulombs, a coulomb being an amp`ere per
second. Where the rate of flow of an electrical current
MATTER, ETHER, AND MOTION 226
is given in amp`eres, the quantity will be found by
multiplying the amp`eres by the number of seconds the
flow has continued. Thus a ten amp`ere current in an
hour will have conveyed 10  60  60 = 36000 coulombs.
There are also measures of capacity. The cubic inch,
the cubic foot, the pint, quart, bushel, and so on, are
measures of volume or capacity: any of them may be
adopted as a unit, and when accuracy is required all
are reducible to the cubic inch as a standard. Thus in
a gallon there are 231 cubic inches.
In electricity the unit of capacity is called a farad,
and it represents the capability of an electrical device
to receive and hold a definite amount of electricity
under the standard conditions of pressure. Thus, when
under a pressure of one volt it holds one coulomb,
the capacity of the apparatus is said to be one farad.
Actually a piece of apparatus of sufficient size to hold
that quantity has to be so enormously large that a
much smaller one was requisite for convenience, and
consequently the microfarad, or the one-millionth of
the farad, has been more generally adopted.
As work may be got out of a flow of water, the
amount of work depending upon the pressure and the
rate of flow, so may work be got from an electric
current, the amount depending upon the pressure,
volts, and the current, amp`eres. The product of these
ELECTRICITY 227
factors, volts into amp`eres, is called watts; and the
mechanical value of one watt is such that 746 is equal
to a horse-power, which, as before stated, is 550 foot
pounds per second. The working power of a watt is
therefore 550
746
= .735 of a foot pound per second.
OHM’S LAW.
This is simply that the current in an electric circuit
may be determined by dividing the electric pressure
in volts by the resistance in ohms. It is customary
to use symbols for each of these factors, E or E.M.F.
(electro-motive force) for the pressure in volts, R for the
resistance in ohms, and C for the current in amp`eres, so
Ohm’s Law when thus written reads E
R
= C. Recurring
to the idea of a wire in front carrying a current of
electricity from the left to the right, and also the
statement that the electrical pressure is greatest at the
left as the cause of the current towards the right, it is
well to remark here that the electrical pressure at any
particular point in a circuit is sometimes spoken of as
its potential. If the potential at some other point in
the circuit be different from the first, the current will
flow from the higher towards the lower. The difference
of potentials may be measured in volts, and expressed
MATTER, ETHER, AND MOTION 228
as E in Ohm’s Law.
There is a very wide difference among different
substances in their ability to transmit electricity. Some
transmit it freely, and are called good conductors;
others transmit it but slowly, and such are called poor
conductors. All solids, and liquids possess some degree
of conductivity; but some of them, such as glass,
rubber, and wax, are so poor in conductivity as to be
called non-conductors. The term non-conductor came
into use before the refined methods now in use for
measuring conductivity were known. It is now believed
that the only non-conductor of electricity is the ether.
If this be the case, then it appears that all the so-called
electrical phenomena in the ether are to be looked
upon rather as the results of electrified matter upon
the ether, than the presence of electricity in the ether,
just as radiations or ether waves are the results of
actual vibrations of atoms and molecules. Conduction,
then, is a general property of matter, and differs in
degrees, that difference depending upon both the kind
of element considered and its molecular combination.
Thus, copper is an excellent conductor; but if copper
be chemically combined with sulphur or with oxygen
its conductivity is greatly impaired.
Conduction, too, implies contact, physical contact,
as in the case of heat; hence solids and liquids may
ELECTRICITY 229
continuously conduct electricity, while gases can conduct
no faster than their individual molecules can move in
their free-path motions, and the rate of electrical loss
is so slow from this source, that for telegraph lines of
hundreds of miles in length it is neglected as being of
no practical consequence. Neither is moist air much
better, and for the same reason. In all cases where
dampness appears to affect the working of electrical
apparatus, the loss is due to the moisture deposited
upon the surface of the apparatus, which thus forms
a thin conductive coating. A Leyden jar may retain
its charge for months if protected from a coating of
moisture, which, of course, it could not do if either
the air or the ether were conductors in any ordinary
sense of the word.
The words conduction and conductivity represent the
property possessed by matter to become electrified by
mere contact with another body that is electrified; but
the terms do not have a very high scientific importance
now, for a much more convenient term is employed
in place, the term resistance, which is the reciprocal
of conductivity, that is, the greater the one the less
the other proportionally. The substance having the
highest degree of conductivity has the smallest degree
of resistance. Resistance is measured in ohms, and is
of two sorts; viz., specific and dimensional. Specific
MATTER, ETHER, AND MOTION 230
resistance is that resistance which depends altogether
upon the nature of the particular element considered,
and may be determined for any element by measuring
the resistance of a cubic centimetre of it.
Tables of conductivity and of resistance of wires are
common, and the following one gives the relative values
of a few of the elements for comparison. The standard
of conductivity being silver and reckoned as 100. The
standard of resistance being a column of mercury
106 centimetres long and one millimetre square, which
has a resistance of one ohm. The numbers given are
the resistances in ohms and fractions of a wire 1 metre
long (39.37 inches) and one millimetre ( 1
25.4 of an inch)
in diameter.
SUBSTANCE. CONDUCTIVITY. RESISTANCE.
Silver, 100 .021
Copper, 99.9 .021
Gold, 80. .027
Aluminium, 56. .037
Zinc, 30. .072
Platinum 18. .116
Iron, 17. .125
Lead, 8.5 .252
German Silver, 8. .267
Hard Carbon, 1. 50.00
Graphite 0.01 Very variable.
The resistance of most liquids, and of such substances
ELECTRICITY 231
as are used for insulating wires, is so very great that
they are given in units called megohms, each a million
ohms. The following represents the resistance of a
few bodies in such terms, the volume being one cubic
centimetre:—
SUBSTANCE. RESISTANCE IN MEGOHMS.
Ice, 284.
Water at freezing-point, 150.
Mica, 84.
Gutta Percha, 450.
Hard Rubber, 28, 000.
Paraffine, 34, 000.
Glass, 3, 000, 000.
Air, Infinite.
These must be read as so many millions of ohms.
Thus, ice 284 millions. Thus can be seen within what
wide limits this electrical property of matter ranges,
and also its significance as a factor in Ohm’s Law,
and why some substances can be practically used as
insulators when in reality they possess a certain degree
of conductivity. Thus, glass is called an insulator. But
if there were a difference of potential or pressure on
opposite sides of a piece of glass one centimetre thick,
equal to 3, 000000 of millions of volts, there would be
a current of one amp`ere passing through for
3, 000000, 000000
3, 000000, 000000
= 1
MATTER, ETHER, AND MOTION 232
In no artificial way can we produce such a voltage
as that; but it is the opinion of some physicists that
the voltage of lightning may rise as high as some
thousands of millions. Under ordinary commercial
voltages of only a few thousands, the current would
be insignificant. Suppose it were 50, 000 volts, then
50, 000
3, 000000, 000000
= 5
300, 000000
= 1
60, 000000
of an amp`ere.
Dimensional resistance is of more practical importance,
for by making a conductor larger its resistance
becomes less. When the cross section of a wire is
doubled, the resistance is reduced one-half. When the
diameter of it is doubled, it is reduced to one-fourth,—a
relation which may be stated as follows: The resistance
of a conductor varies inversely as its cross section, or
the square of its diameter if it be a wire; so by making a
relatively poor conductor large enough, it may transfer
as large a current as a much better specific conductor
of smaller dimensions. In the table it is shown that the
resistance of copper to that of iron is as .021 to .125,
or that the latter is six times the former. If, then,
the section of the iron wire be made six times larger,
it will have the same degree of conductivity as the
copper. This means that one pound of copper is worth
ELECTRICITY 233
nearly six pounds of iron for electrical conduction; and
whether the one or the other should be employed in a
given place depends chiefly upon the relative costs. It
is a commercial rather than an electrical question. The
resistance of all conductors varies with their length.
Temperature also affects the conductivity of nearly
all bodies. Some have their conductivity increased by
heat, as is the case with carbon; others have their
conductivity increased by cold. Thus, the conductivity
of copper at 100 below zero is increased nearly ten
times.
An idea of the relative magnitude of the factor of
resistance in common electrical work may be gained
by knowing that a mile of ordinary electric arc-light
wire generally has a resistance of about two ohms;
telegraph and telephone wires five or six ohms, and
often more, per mile. If there be a current of ten
amp`eres going through a mile of wire that has a
resistance of one ohm, then Ohm’s Law enables one to
determine what is the difference in pressure between
the ends; for E
R
= C and E = RC = 1  10 = 10 volts.
So if any two of these factors be known, the other
may be computed. The E gives the available electrical
pressure; the R gives the conditions under which it
can work, and the C gives their resultant, the available
MATTER, ETHER, AND MOTION 234
current, while the product of EC gives the activity, or
rate at which energy is expended in the circuit, while
if this product be divided by 746, the horse-power of
the circuit will be given.
The further significance of Ohm’s Law and its utility
will be given farther on, when considering the relation
of electrical energy to mechanical energy.
INDUCTION.
It has been pointed out that the term conduction
signifies the transferrence of electricity from one body
to another by contact,—contact in the sense that the
molecules of solids and liquids are in contact when
they cohere, and when their individual vibrations
cannot take place without mutual interference. It is
found that bodies become electrified by merely being
in the presence of another body that is electrified,
without material contact, and the more perfect the
vacuum between the bodies the more freely does this
phenomenon take place. As the electrified body that
thus affects other bodies in its neighborhood does not
lose any of its own electricity, does not share it with
other bodies in any degree, and as the other bodies
lose their electrification by simply being removed to a
distance, and will recover it again by being brought back,
ELECTRICITY 235
it follows that the action is entirely distinct from the
phenomenon of electrical conduction. A similar body
electrified by conduction will retain its condition, and
distance will make no difference. This kind of action is
called electrical induction. To understand what changes
take place, it will be needful to attend particularly
to the factors present. Under the head of Electrical
Origin of Electricity, it is pointed out that an electrical
current may be induced in a circuit adjacent to another
circuit in which a current is produced in any way;
and here are similar conditions and similar phenomena.
Imagine an electrified body freely suspended in the
air. If a gold-leaf electroscope is brought within a few
feet of it, its leaves will diverge; if brought nearer
they will diverge still more; recession will cause them
to collapse. This movement of the leaves can be
produced indefinitely by changing the distance of the
electrometer from the electrified body. It is important
to note here that it requires the expenditure of energy
to move the gold leaves, though the amount may be
small. If it may be done for an indefinite number
of times, then the energy spent may be indefinitely
great; and that it is not directly derived from the
electrified body itself is certain; for the latter loses by
the process none of its electricity, and cannot lose it
except by conduction. Evidently the body has in some
MATTER, ETHER, AND MOTION 236
way modified the physical condition of the space about
it so that another body within that space is affected
somewhat as it would be if touched by an electrified
body. But the property belongs to the space itself, and
cannot be extracted from it so long as the electrified
body remains in place. This space about an electrified
body within which other bodies assume an electrical
condition is called an electrical field. It may extend to
an indefinite distance from it, and its strength has
been found to vary like gravity, being inversely as the
square of the distance. This new physical condition
into which the space has been brought by the electrified
body is known to be the effect of the latter upon the
ether, and is called its electrical stress. It is simply the
reaction of the one upon the other, and indicates that
the molecules stand in abnormal strained positions.
A mechanical idea of what it is like may be got by
pressing the hand upon the top of a table, and then
producing a twisting strain tending to turn the table
round, but without moving it. The whole table will
be subject to a stress that will react upon the hand,
a condition which will, of course, be retained by the
table as long as such pressure is kept upon it. For
the hand substitute an electrified mass of matter, and
for the table the ether in any direction about it, and
one will have a fair conception of the electrical field.
ELECTRICITY 237
Especially so, if he will add to it that such twisting
effect can be either right-handed or left-handed, and
so produce those distinctions known as positive and
negative, which run all through electrical phenomena.
A body brought into this distorted field of ether is
acted upon by the latter tending to twist its molecules
into new positions with reference to each other, which is
precisely the condition that brought about the original
stress, that is to say the electrical one, with this
difference, that if the original one was right-handed the
reaction of the ether would be left-handed, or exactly
opposite that of the inducing body. This is simply
because action and reaction are equal to each other
and opposite.
One can now understand how it can be that
bodies can be electrified by induction without loss of
electrification by the inducing body. There are three
steps in the process. 1st, The body electrified in any
known manner. 2d, Its resultant stress in the ether.
3d, The reaction of the ether upon the second body,
inductively electrifying it. Electricity has not been
conducted by the ether, but a stress has been, and
the ether stress has electrified the second body. By
periodically electrifying and delectrifying a body, a
series of stresses will be produced about it which will
travel outwards as a succession of waves, the velocity
MATTER, ETHER, AND MOTION 238
of which is the same as that of light, 186, 000 miles per
second, and the wave length of which will depend upon
the number of electrifications per second. Suppose a
sphere, like a cannon-ball in free space, to be connected
by wire, so that by pressing a Morse telegraph key in
connection with any source of electricity it could be
charged and discharged at will. If the key was closed
regularly once a second, the wave produced would be
186, 000 miles long. If it could be closed 186, 000 times
per second, the wave would be one mile long. And if
it could be closed so often that the wave length should
be but the one fifty-thousandth of an inch, there is
every reason to believe that the eye would perceive
the waves as light; not so much because the waves
were produced by electrical means, as that the eye is
capable of perceiving ether waves of that length, no
matter how they may originate.
The analogy between heat and electrical phenomena
in the ether is very close. The ether receives the
energy from both sources and transforms it. The ether
is not a conductor of either heat or electricity: it is
neither heated nor electrified by them, but in each
case is simply a medium for the distribution of such
energy as gets into it according to its own laws, and
quite independent of its source. When heat gives up
its energy to ether it becomes ether waves or radiant
ELECTRICITY 239
energy, and is no longer heat: it has been transformed.
When radiant energy falls upon other matter it is again
transformed into heat. In like manner, when electricity
gives up its energy to the ether, it becomes radiant
energy also, and when this falls upon other matter it
is again transformed into electricity. I have been thus
particular to enlarge upon induction, and point out the
factors present, in order to make it clear how entirely
distinct the electrical condition in matter is from the
electrical effect of it upon the ether. It is from a
failure to keep these distinctions in mind that so many
have been mystified by electrical phenomena, and so
many different theories have been propounded as to
its nature.
In all our experience electricity originates in matter,
and whatever the particular character of the phenomenon
in matter, it ought to have a different and distinct name
from the effect of such phenomenon upon the ether. If
such endowment of matter be called electricity, then it
is not proper to use the same word for its stress, or
wave effect, in the ether, and this for precisely the same
reason as is allowed to hold good in heat phenomena.
Formerly ether waves were called heat, afterwards heat
waves, now radiant energy, for it is known that there
is no heat in the ether.
MATTER, ETHER, AND MOTION 240
EFFECTS OF AN ELECTRICAL CURRENT—1. MAGNETISM.
If a wire through which a current of electricity is
passing be twisted into a loop or ring, it is found
that the loop acts in all ways like a magnet. Its sides
have polarity; and if it be so mounted as to be free to
assume any direction, it will move so its sides face the
north and south. If a piece of iron be placed in the
ring, the magnetic effect will be greatly strengthened.
Soft iron, however, loses its magnetic property as soon
as the current stops. A piece of steel will retain some
portion of the magnetic condition, and so is called a
permanent magnet. A given current of electricity will
make a much stronger magnet of a piece of soft iron
than it will of a piece of steel, and this is explained
by saying that the iron is more permeable to magnetism
than steel is. Once in possession of a magnet, one
may proceed to study its physical properties in many
ways. That a magnet possesses poles; that it can attract
and hold to itself iron, steel, nickel, cobalt, and affects
other substances but slightly; that it is attractive to
unlike poles of other magnets, and repulsive to similar
poles,—and so on, are phenomena so widely known
that they need not be described here. Only such
phenomena will be considered as will be helpful to an
understanding of the constitution of a magnet, and its
ELECTRICITY 241
relation to electricity and to the space about it.
The magnetism of a magnet seems to reside chiefly
near its ends, for these will sustain bits of iron,
but near the middle it will not; and when a small
compass-needle is moved around a bar magnet, it
points towards one end or the other, except when near
the middle, where it sets itself parallel. When such
a bar magnet has a sheet of paper laid upon it, and
iron filings are sprinkled upon the paper, the filings
are arranged in curious curved lines, starting from one
pole and traceable to the other, and quite around the
magnet on both sides. This arranging power of the
Diag. 20.—Magnetic Lines.
MATTER, ETHER, AND MOTION 242
magnet extends in every direction about it, as one can
satisfy himself by trying the same experiment with the
magnet turned on different sides. If one will compare
the direction of these lines of filings with the positions
of the needle, he will see that the needle assumes the
same direction at any given place. Near the poles the
lines all converge to it, and opposite the middle the
lines are parallel with the magnet. If the magnet be of
a U or horse-shoe form, the lines will be found still to
extend from one pole to the other, some straight, some
curved outwards, but always forming a curve such as
to touch each pole of the magnet. While the filings
are in the position described, let the paper be gently
tapped with a pencil so as to jostle them slightly, and
they will begin to close up in such a way as always
to shorten themselves, and presently they will form a
dense mass between the poles, adhering to the latter
as a solid piece of iron would do.
Such phenomena show that the magnet in some
way reacts upon the space about it, so that iron and
other magnets there are affected, just as an electrified
body affects the space about it, as has been described.
This space about a magnet within which such effects
are produced is called the Magnetic field, which may
be said to be the stress in the ether produced by
a magnet. Like the electric stress, it extends to an
ELECTRICITY 243
indefinite distance from the magnet, and travels with
the velocity of light; so if a magnet was charged and
discharged once a second, a wave motion would be set
up: the wave length would be 186, 000 miles long, and
if it could be charged and discharged so fast that the
waves were but the one fifty-thousandth of an inch in
length, it is very probable they would be perceived as
rays of light, and the magnet would be a luminous
body. Such waves are called electro-magnetic waves.
At present the shortest waves of this sort, that can
be artificially produced, are several inches long, but it
seems highly probable that before long some way will
be discovered of making them of the required length
for vision.
If a test-tube filled with iron filings be held near a
delicate suspended magnetic needle it will be found
to give no indication of polarity, one part will act just
like any other part, and the magnet will be equally
attracted. Bring the test-tube against the poles of a
strong magnet for a few seconds, and then it will be
shown that the filings have become magnetic, and now
one end of the tube will attract one pole of the needle,
while the other end will repel the same end. Shake
up the filings well, and the polarity will be destroyed.
Stir up iron filings with melted wax, and pour into
a paper mould, so as to form a stick the size of the
MATTER, ETHER, AND MOTION 244
finger, or larger. If this be tested for magnetism, it
will be found without any; but magnetize it as if it
were a piece of steel, and it will be found to retain it,
becoming a permanent magnet. If a layer of iron be
electrically deposited upon a brass wire in a magnetic
field, the wire acts like a magnet. All these phenomena
go to show that what is called polarity or magnetism
is due to the positions of the molecules, rather than upon
some sudden endowment which the molecules receive
and may lose. Imagine every molecule of iron to be a
magnet, having its poles or faces, then if in a mass of
them, such as makes up a piece of iron or steel, all be
made to face one way and keep such position, all will
act in conjunction to give polarity to the mass. When
some molecules face one way, and others adjacent to
them face the opposite way, they will but neutralize
each other, so the external evidence of magnetism
will be destroyed. How atoms may be magnets and
exhibit polarity may be imagined by considering the
phenomena of vortex rings again. In the ring all the
motion on one side is towards the middle of the ring
inwards, on the other side all the motion is outwards,
so the properties of the two sides are opposite. Each
such ring must have its own field, which may extend to
an indefinite distance from it, and may be represented
roughly by the diagram in which the curved lines show
ELECTRICITY 245
the same features before described as belonging to a
magnetic field. When two or more are facing the same
way, and are in contact, these lines cannot re-enter the
ring except by going round the second one; and when
many are in line they must go round them all, in
which case the direction of the lines will be precisely
Diag. 21.—Field of a
Ring.
Diag. 22.—Coinciding
Fields.
Diag. 23.—Opposing
Fields.
those observed about a straight bar magnet.
When they all face one way, as in diagram 22,
the resultant will be at A, the sum of the outgoing
movements, and at B, the sum of the ingoing ones,
and polarity at A and B will be at a maximum. If
they face in different ways, each will tend to cancel
the other, and there will be no external field; as in
diagram 23.
MATTER, ETHER, AND MOTION 246
If two such atoms be brought face to face, each
will be blowing against the other; their fields overlap,
and the stress is increased between them, and they
are crowded away from each other,—a phenomenon
called repulsion. The opposite condition obtains when
they face the same way and are near together, with
the result that the stress is lessened between them,
and they are pushed together by it; and this is called
attraction.
There has been growing the conviction for a long
time that the atoms of all substances are magnetic;
but when they combine into molecular groups they
are turned about so their magnetic fields neutralize
each other, and thus it happens that most molecular
compounds show no polarity. But every substance
whatever is attracted by a magnet, and will move up
to it if the magnet be a strong one. Brass, lead, stones,
oats, corn, and wood will all be affected alike by a
strong magnetic field, being pushed towards the magnet
in the same way as iron, though not in the same
degree. The pressure of iron against a magnet, due
to the magnetic field, may be as great as a thousand
pounds per square inch.
When a piece of iron is brought near to a magnet,
and it becomes a magnet by induction instead of by
contact, it is to be understood that its molecules are
ELECTRICITY 247
rotated into similar positions by the action of the
magnetic field upon it, not that magnetism has gone
from the magnet to the iron; and when it requires a
pull, and therefore work, to move a piece of iron away
from a magnet, it is against the ether the work is done.
It was stated at the outset that a loop of iron through
which an electric current is passing is a magnet, and
previous to that it was pointed out that an electric
Diag. 24—Iron Filings about
Electric Current.
current in a wire has a field
that extends indefinitely out
from it. If such a wire be
dipped in iron filings, they
form rings round it, showing
that the polarity is at right
angles to the wire. Now, if
the wire with the iron filings
clinging about it be made into
a loop, it will be seen at once how the polarity of
the different segments is all in one direction inside
the ring, and opposite to that on the outside the ring,
and the structure will be a forcible reminder of a
vortex ring. If several similar turns be taken in the
wire, and they all be brought near together so as to
form a helix, it will also be seen that these conspire
together to set a boundary to the field on the inside,
but allow indefinite expansion to it outside; so if one
MATTER, ETHER, AND MOTION 248
should draw the lines for it as iron filings would be
arranged by it, he will have the precise lines of a
magnet, while the ring structure will be, on a large
scale, just what was described on an atomic scale as
constituting a vortex ring magnet; and the only thing
lacking to complete the analogy is the conception of a
rotary motion in the wire at right angles to its length.
Diag. 25.—Adjacent
Turns.
It has been found that when a
current has been started in a conductor,
a torsional impulse is given to the
latter in such a sense that if one
looks along it in the direction of the
current the twist is in the direction
of the hands of a clock. So there is direct confirmatory
experiment showing that the nature of the motion in an
electric circuit is rotary in such a way that the whole
circuit may be considered as a vortex ring; and as it
is the matter of the conductor that is thus rotated, it
follows that electrical current motion is rotary, as heat
motion is vibratory.
Allusion has been made to the opinion now current
that ether waves or light are electro-magnetic phenomena.
How this can be may be understood by considering a
magnet of any form, with its surrounding field. If the
form of the magnet be changed, the shape of the field
will be correspondingly changed; and as this extends
ELECTRICITY 249
out indefinitely into space, it follows that a succession
of changes of form would set up waves through the
whole of that space. Now, a magnet is an elastic body,
and if it be struck it will vibrate and produce a sound.
The vibration implies a change of form, and that in
turn a set of waves radiated into space. As the field
is an ether field, the waves will be ether waves. Now
assume that atoms are themselves elastic magnets, each
with a field indefinitely extended, and it follows that
the vibrations produced by impact, or in any other
manner, will set up corresponding waves in the ether,
the wave length depending upon the vibratory rate
of the atoms. Thus ordinary radiant energy, or light,
would consist of undulations in a magnetic field.
Of course it will be perceived that vibrations of any
electro-magnetic body, large or small, would induce
similar waves, differing only in wave length, so there
would be in the ether wave lengths of all dimensions,
from the shortest possible to those millions of miles
long. It is now an important physical problem how to
produce such that shall be of the dimensions capable
of affecting the eye.
MATTER, ETHER, AND MOTION 250
Induction Coils.
One or more loops of iron, through which a current
of electricity is flowing, is an electro magnet. When iron
is placed in the loop, it condenses the magnetic field,
and it may be made as much as thirty times stronger
than it would be without the iron. When a magnetic
field is produced inside a loop of wire, the reverse effect
Diag. 26.—Electro-Magnetic
Induction.
happens, and a current is generated
in the opposite direction.
Suppose a short rod of iron
to have a single turn of wire
at each end about it, one of
them, as A, to be so connected
to a source of electricity that
a current through it may be
produced by closing a key, the other one to be a
closed circuit, as shown. If a current be established
through A in one direction, a current will be induced
in B, as indicated by the arrow. There will be in the
loop of the A circuit a certain electro-motive force, E.
A nearly equal electro-motive force will be induced in
loop B. If there were two loops at B instead of one,
the electro-motive force would be twice that in A, and
for n turns it would be n times. The current in B will
depend upon the resistance in its circuit; that is, it will
ELECTRICITY 251
be E
R
= C, according to Ohm’s Law. The size of the
wire in B circuit will not make any difference in the
value of E in it. That value will depend only upon the
magnetism of the bar, and the magnetism in the bar
will be measured by the product of the current into
the number of turns of wire in the circuit A. And this
product is called the amp`ere turns. The amp`ere turns
will be nearly equal in the two circuits. This process
of obtaining electrical currents in a second circuit by
two transformations is of great use in the electrical
industries, and the device is called an induction coil or
transformer. The charging circuit is called the primary,
and the discharging one the secondary. By making
circuit A of a small number of turns of thick wire, so
as to allow strong currents in it, and having circuit B
consist of a great number of turns, the electro-motive
force may be raised almost indefinitely. Suppose there
be 100 turns in the A circuit, and a hundred thousand
in the B circuit, then for every volt in the A circuit
there may be nearly a thousand volts in the B circuit;
and this is the construction in those instruments known
as induction coils, with which so called jumping sparks
are produced, and represent sometimes a million or
more volts. On the other hand, it is sometimes desirable
to change a high electro-motive force to a lower one;
MATTER, ETHER, AND MOTION 252
and this may be done by reversing the connections and
making the primary current go through a great number
of turns, and taking the induced current from the
smaller number of turns in the other circuit. Definite
reduction in either way may be effected by making the
ratio of the number of turns in the two circuits the
reduction wanted. That is to say, if there are 100 volts
in the primary circuit, and only ten are wanted, make
the secondary of one-tenth the number of turns in
the primary. If a thousand volts are wanted, make
the secondary with ten times the number of turns
in the primary. It should be remembered, also, that
two turns of wire in B have twice the resistance of
one turn, and the current induced will be reduced
to one-half. If there be one hundred turns, it will
be reduced to one-hundredth and so on. Hence, in
the large induction coils for high electro-motive forces,
the current is necessarily a small one, while in the
transformers in which the reduction is to lower values
of E than are in the primary, the current may be very
great indeed. This is the case in Thompson’s Welding
Apparatus. The secondary has but a single turn of
heavy copper, while the primary has many thousands,
and the current in the secondary may be thousands
of amp`eres. As the heating effect is proportional to
the square of the current, it is plain that such large
ELECTRICITY 253
currents have enormous heating power.
All such devices require either intermittent or
alternating currents to operate them, for there is no
induced current in any circuit when the inducing
magnetism is not changing. A constant magnetic field
induces no electrical changes.
The Electro Magnet.
This is generally considered as consisting of a helix
of insulated wire about a piece of soft iron, and may
be either a straight bar, or crooked in any convenient
form, its function being to produce a magnetic field
when a current circulates in the wire, and to lose it
when the current stops. This it does only partially, for
all iron when once it has been magnetized becomes
more or less permanently magnetic; hence there is only
a difference in degree between an electro magnet and
a permanent magnet. Until within a few years the
electro magnet had its most extensive field of usefulness
in telegraphy. It was combined with a piece of soft
iron near its poles called its armature, which was
so mounted that the magnetic field made it to move
towards the magnet, and a retractile spring pulled it
away when the field was absent. The movement of the
armature was employed to receive signals. In some
MATTER, ETHER, AND MOTION 254
cases the movement recorded itself, and sometimes its
prompt motion produced a sound, a succession of these
being arranged into a telegraphic alphabet.
If one has a good idea of a magnetic field and its
action upon a piece of iron in it, he will be able to
understand all the various combinations of forms and
functions of electro-magnetic devices, however much
they may apparently be disguised. Thus, the magnetic
telephone is an electro magnet with an armature of
such size and flexibility as to be capable of much
quicker movements than ordinary telegraph instrument
armatures, the whole boxed so as to be convenient to
hold to the ear. A common telegraph sounder acts in
precisely the same way, though not so well, for the
armature is too heavy, and one cannot concentrate its
effects upon the ear on account of its form. An electric
bell also produces its ring by having a hammer fixed
to the armature, so as the latter moves in response to
the electric field it strikes the bell.
An electric motor, in the largest sense, consists
of a device for transforming electric into mechanical
motions; and the relation sustained between an electro
magnet, its field and an armature, is such as to do
it directly. A telegraph sounder is thus a simple
motor, for the armature moves visibly in response to
the electric current. If a wire be wound about the
ELECTRICITY 255
armature, there is an induced current in it, as in
an induction coil, and for the same reason; and the
movements of the armature towards and away from
the poles of the electro magnet, called sometimes the
field magnet, give rise to currents in the armature coil.
If a current from another source is sent through the
armature coil, it gives polarity to the armature itself,
and the reaction between it and the poles of the field
magnet is still stronger, and the mechanical motions are
still more energetic. The armature thus wound with
wire is obviously an electro magnet itself, and when it
is so mounted as to be capable of rotating between the
poles of a fixed electro magnet, a continuous rotation
may be kept up.
The current in the fixed magnet is steady, and
therefore maintains a steady magnetic field. The current
in the armature magnet is changed in direction by the
motion of the armature itself, and is effected by a
device called a commutator. The efficiency of such a
motor may be as high as 90% or more. That is, for
every horse-power of electrical energy turned into it, it
will give back nine-tenths of a horse-power in actual
work. The small space they occupy for the working
capacity, when compared with a steam-engine for the
same work, the small amount of attention they require,
and their freedom from the dirt inseparable from an
MATTER, ETHER, AND MOTION 256
engine, commend the electric motor as a substitute
for the engine in most places where power is wanted
and an electric current can be had; for it is to be
remembered that fifty horse-power can travel through
a wire that can go through a gimlet-hole, while a
steam-plant for the same work would require a large
boiler and engine as well as a big chimney.
When the armature of a motor is made to turn
by mechanical means, the shifting positions in the
magnetic field develop electric currents in its coils.
Such an armature cannot be turned as freely when the
field magnet has a current in it as it can when it has
not, and the energy spent in making it turn appears as
a current. The device is called a dynamo, which may
be said to be a machine for transforming mechanical
motion into electrical motion. The steps are mechanical
motion, magnetic field, electrical current; while in the
motor they are simply the reverse,—electric current,
magnetic field, mechanical motion.
The efficiency of a dynamo is very high indeed.
It can transform 95% of the power applied to it into
electrical power, and in this particular it is one of the
most perfect machines in existence. There is absolutely
no room for any important improvement in the dynamo
as regards its efficiency. A good steam-engine may
transform ten to fifteen per cent of the energy turned
ELECTRICITY 257
into it. A windmill may give fifty, a turbine water-wheel
ninety, but when a dynamo gives ninety-five, it shows
that the coming man has a margin of but five per cent
for improvement in its efficiency.
Thus the magnetic field, which is simply the ether in
an abnormal condition of stress, is the common agency
between mechanical motions and electrical phenomena,
and transfers energy one way or the other. All that
determines whether it shall be one way or the other is
simply which side has the excess of energy; for energy
of a particular sort always goes from the body having
more to one having less. Which side has the excess is
determined solely by the mechanical conditions present.
Electric Lighting.
An electric current always heats the conductor
through which it is passing. The amount of heat
depends upon the strength of the current, and varies
as the square of it. In a given circuit with a uniform
current, the current has the same value, and therefore
the same heating power, in every part of that circuit;
but the temperature to which a body will be raised by
a given current depends upon its own constitution, its
size and electrical resistance. Connect together three
wires of copper, iron, and platinum, each a foot long,
MATTER, ETHER, AND MOTION 258
and of the same diameter, and make them a part of
the same circuit, so that the same current shall flow
through them. If the current be increased gradually, the
iron wire will grow appreciably warm, more current
will make it hot; platinum wire will be only warm;
while the copper wire will not have its temperature
much changed. Still more current will make the iron
red-hot, the platinum uncomfortably hot, and warm
appreciably the copper; and more current will fuse
the iron, perhaps make the platinum red-hot, but the
copper may not yet be uncomfortably hot. This heating
effect in a given wire is found to be proportional to its
resistance: the iron wire having the greater resistance
is most heated, and the copper having least, is least
heated; hence to obtain a high temperature with a
given current, a conductor must be chosen that has a
relatively high resistance. Resistance, however, varies
with the cross section inversely, so a small wire must
be taken if the temperature of incandescence is to be
reached with a small current; and a current that will
raise half an inch of a wire to a white heat will raise
a mile, or any other length of the same wire, to the
same temperature; but the longer a wire is, the higher
must be the electro-motive force in order to get the
same current. For a given length of a wire the electrical
energy spent in it will be found by multiplying its
ELECTRICITY 259
resistance by the square of the current, RC2, which
will give the products in watts, of which 746 equal
a horsepower. Metals are liable to fuse and become
useless, so that wires of carbon, made by heating
organic fibres in the absence of air, as in making
charcoal, are substituted for metals. They fuse only
at extremely high temperatures; and being enclosed in
a vacuum in bulbs of glass they cannot burn up as
carbon does when exposed to the air when red-hot.
This is the electric incandescent lamp. Most of them
are so prepared that a current of about three-fourths of
an amp`ere is required to properly light them, and this
will be got when the difference of potentials between
the lamp terminals is kept at a certain figure, so
that lamps are specified by the number of volts they
require, rather than the current; thus there are 50 volt
lamps, 110 volt lamps, and so on. Now, such lamps
take ordinarily about four watts for a candle, so a
twenty candle-power lamp requires eighty watts, and
that means 746
80
= 9.3 such lamps to the horse-power.
Such lamps may last for a thousand or more hours.
If a stronger current be used, they shine brighter, but
their life is shortened. There is a process of slow
disintegration going on in these lamps all the time. The
surface molecules slowly evaporate under the vigorous
MATTER, ETHER, AND MOTION 260
vibratory movements present, and the carbon vapor
thus formed sticks to the inside surface of the bulbs,
giving them the familiar blackened appearance.
The Arc Light.
If an electro-motive force of forty or more volts be
maintained in a circuit, and the circuit be broken at
some place and the ends separated a small fraction of
an inch, the current does not cease, and is maintained
between the ends by what is termed an arc, where the
temperature is so very great that almost all substances
are reduced to vapor at once. All metals are fused
and dissipated there. Carbon does not fuse there, but
is slowly burnt up. The ends of the carbon reach a
temperature higher than can be reached in any other
known way, and the light they then give out is called
the arc light. The rate of expenditure of energy in
that small space where the brightness is, is generally
some less than a horse-power. The current employed is
about nine and a half amp`eres, and the electro-motive
force about forty-five volts; hence 9.545 = 427.5 watts,
and such a lamp may be equal to 800 candles, though
they are generally rated as 2, 000 candle-power.
By increasing the current the brightness increases,
and there is no especial limit to the amount of light
ELECTRICITY 261
that may in this way be produced. With parabolic
reflectors the light may be concentrated into a powerful
beam. The inhabitants of Mars could see such a one,
and it could be used for signalling between the two
planets if the Martians had a similar one.
Seeing that the temperature to which a given
conductor can be raised by a current is determinate,
one can arrange for heating on any scale. There is no
other reason than the relative cost of electric heating
compared with the ordinary method with fuels, why
it should not be in common use to-day. In most
places the dynamo for the production of the current
would be run by a steam-engine, requiring in its turn
a furnace; and it is cheaper to use the fuel direct for
heating, than to transform the energy so many times,
each time with some loss. A common furnace is much
more economical of energy than a steam-engine. But
if ever electricity is obtained directly from combustion
in an economical way, as there is some reason for
thinking possible, electrical heaters will displace stoves
and the common furnaces in the house. So the same
current that lights the house will serve for cooking and
warmth.
MATTER, ETHER, AND MOTION 262
2. CHEMICAL EFFECTS.
When a current of electricity is passed through
conducting liquids capable of being decomposed, such as
acidulated water, and solutions containing more or less
of the metallic elements, decomposition of the solution
results, with the additional curious phenomenon that
one of the elements of the decomposed compound
appears at one terminal, and the other element at
the other. Thus, if water be the liquid, hydrogen
appears at one place and the oxygen at another. If the
two terminals of an electric circuit were on opposite
sides of the Atlantic Ocean, and a current were sent
through the circuit, hydrogen would appear on one
side and oxygen on the other. The oxygen is set free at
that terminal at which the current reaches the liquid.
The direction of the current being determined in the
ordinary conventional way. Bring the wire carrying
the current over and parallel to a suspended magnetic
needle. If the current be going from south to north, the
north pole will be deflected to the west. If the current
be going from north to south, the south pole will be
deflected to the west. Hence, if one looks along a wire
in the direction of the current, oxygen will be given
off at the next terminal if it dips in water. It may be
convenient to know that when a battery is employed
ELECTRICITY 263
as a generator of electricity, hydrogen is set free at the
terminal of the battery from which the current flows,
and oxygen at the other end of that conductor.
The decomposition of water may be taken as a type
of electro-chemical work; hence, when the mechanical
conditions present where decomposition is going on
are understood, they may be applied to any other case.
Under the head Chemical Origin of Electricity it
was pointed out that the same factors which gave
rise to the current also arranged the molecules of
the liquid so that the oxygen sides of them all faced
the same way, towards the zinc, which of course
necessitates that the hydrogen sides should all face
in the opposite direction. The other terminal of the
battery tends to bring about a similar condition of
things, so that between the terminals the molecules are
all polarized or brought into an orderly arrangement.
The direction of the electric current in such an arranged
body of molecules in the liquid is from the zinc to
the oxygen—oxygen, hydrogen, oxygen, hydrogen, and
so on to the last molecule in the line, the hydrogen
face of which is against the other terminal. So far
this represents molecular arrangement, not molecular
or atomic cohesion. There is good reason for thinking
that dissociation of atoms in such molecules is going
on all the time in some degree, on account of their
MATTER, ETHER, AND MOTION 264
incessant and vigorous vibratory motion. Such motion
must tend to disrupt the atoms so that at any given
instant there would be a relatively large number of
atoms in the liquid already free and quite indifferent
as to whether they recombine with the same or other
atoms the next instant. If there be another agency
present, like an electrical current, adding its energy
tending to disruption, not only would a larger amount
of dissociation take place, but when at one end of the
line one element of the molecule, like oxygen, enters
into a new combination which is more stable under
the conditions present, the remaining hydrogen will
combine with the oxygen of the adjacent molecule when
that molecule is broken up, and so on along the whole
line, leaving the hydrogen of the last liquid molecule
to be freed against the other plate of the battery. This
means that there is an exchange of partners among
all the molecules of the liquid that take part in the
current, else some of both oxygen and hydrogen would
be set free elsewhere than at the terminals, which never
happens.
Now, all molecules are combinations of atoms in
definite proportions by weight, and it is therefore to be
expected when such decompositions as the above take
place the products will be found in the same proportions.
It is the necessary outcome of the operation. So for
ELECTRICITY 265
every one part by weight of hydrogen set free, eight
parts of oxygen will be liberated; and for a like reason
twice the volume of hydrogen as of oxygen.
If a current of electricity be led through any
liquid which it can decompose, and the material of
the terminals be some substance that neither of the
constituents of the molecule can combine with, both
of the elements will be set free. Platinum is such an
element; and if terminals be made of that, and dip into
a tank of water, the current polarizes the molecules
precisely as in the battery, and decomposition takes
place in the same way,—oxygen being set free at the
in-going terminal, and hydrogen at the out-going one.
If the solution contains molecules of metallic salts of
copper, nickel, iron, silver, gold, etc., the metallic side
of the molecule faces in the direction of the current,
the same as the hydrogen in the former case; and
as a consequence, the metal is deposited upon the
out-going terminal, whatever that may be, and the
other constituent of the molecule is set free at the
in-going terminal. For example, the sulphate of copper
is a compound of copper and sulphuric acid. Where it
is subject to decomposition by an electric current, the
copper is deposited at the one terminal, and sulphuric
acid at the other. If both the terminals be made of
platinum, one will be covered with copper, and the
MATTER, ETHER, AND MOTION 266
other will be surrounded with the acid, and all the
copper in the solution may be taken out. If the in-going
terminal be itself of copper, the sulphuric acid set free
will itself dissolve off the copper as fast as the acid
is set free, and in this way the solution will be kept
saturated. The metal may be deposited on any other
metal. It is in this manner that electro-plating of all
sorts is done. Each different metal requires different
treatment from the others as to solution, electro-motive
force, current per square inch section, and so on for
the best results. To decompose water, as much as one
and a half volts are necessary to initiate it, but copper
salts require only a small fraction of one volt. The
amount of decomposition in a given time, say a second
or an hour, depends upon the current employed. A
current of one amp`ere will in an hour decompose only
about fifteen and four-tenths grains of water, liberating
one and seven-tenths grains of hydrogen. The weight
of other elements set free or deposited by an amp`ere
per hour is determined by multiplying the weight of
hydrogen set free by the electro-chemical equivalent
of the element, and this is either equal to its atomic
weight, or is one-half or one-third that. Thus, the
electro-chemical equivalent of gold is 196.6
3
= 65.5, of
silver 108
2
= 54, of copper 63
2
= 31.5, of nickel 57
2
= 28.5,
ELECTRICITY 267
and so on. So the amount of gold that will be deposited
by an amp`ere in an hour is 1.7  65 = 111.35 grains;
of silver 1.7  54 = 91.8 grains and so on. This shows
a definite relationship between electricity and chemical
reactions.
It is to be kept in mind that when substances
combine there is always some transformation of energy,
and heat is either absorbed or given out. When
hydrogen and oxygen combine there is a large amount
given out, 61, 200 heat units for each pound of hydrogen.
When, therefore, water is decomposed so as to set free
one pound of hydrogen, the same amount of energy
must be spent to do it. The electrical energy spent in a
decomposing cell is, therefore, reducible to the heating
effect, and may be calculated as such.
3. LUMINOUS EFFECTS.
When an electric current passes from one conductor
to another through the air an electric arc is produced,
and great heat and light are developed there. An
arc is generally about an eighth of an inch long. By
having a higher electro-motive force one may be made
several inches long. The arc itself consists of the
incandescent molecules of the air in its path mixed
with some of the disintegrated particles of the carbon
MATTER, ETHER, AND MOTION 268
of the terminal. When an arc is formed in a partial
vacuum the character of the phenomenon is very much
changed. Instead of being concentrated into a narrow
space, it spreads out into an oval form, the size of
which depends upon the degree of exhaustion. The
terminals may be separated to a much greater distance;
the light becomes less intense, and shows as a kind
of glowing gaseous globe, and this may extend to the
walls of the glass vessel in which it is produced.
If the vacuum be made very perfect, no current
can be got through it; for the ether is a perfect
non-conductor. Even the spark from an induction coil
that will jump several feet in the air will not jump
a quarter of an inch in a vacuum. The jumping
ability of an electric spark or current depends upon
its electro-motive force. A thousand volts will jump
but about the one-hundredth of an inch in common
air, and ten thousand volts only about one-tenth of an
inch. From such experiments it has been concluded that
a flash of lightning probably has an electric pressure
reckoned by hundreds of millions of volts, but there is
some doubt about the calculation for such exceedingly
high voltage. Glass tubes provided with platinum
terminals hermetically sealed, and from which the air
has been partially removed, when connected with the
high voltage terminals of an induction coil exhibit
ELECTRICITY 269
phenomena that depend altogether upon the degree of
exhaustion in the tube. If the air pressure be removed
to about the one-hundredth of the normal pressure,
the discharge appears as a broad band of purplish
light between the terminals; if the reduction be to
the thousandth, the light fills the tube. Still further
reduced, the discharge appears broken up into striæ,
or bright disks, their distance apart depending upon
the degree of exhaustion, and they measure roughly
the length of the free path of the gaseous molecules.
If the exhaustion is carried to a very high degree, this
free path may be made as long as the tube, or longer.
This means that a molecule may move from one end
of the tube to the other without coming into collision
with another one.
When a molecule touches upon the electrified
terminal, it is impelled from it with great velocity, quite
like that exhibited in the radiometer, and probably for
the same reason. It moves away from the terminal in
a straight line in obedience to the first law of motion,
and continues on till it strikes another molecule, or
the surface of the tube, and it shines as it moves, on
account of its vigorous internal vibrations; for each gas
gives its characteristic spectral lines when thus made
incandescent. Where they strike upon a thin piece of
platinum they may make it red-hot by impact, and
MATTER, ETHER, AND MOTION 270
Diag. 27.—Crookes’s Tube. Long Free Path.
ELECTRICITY 271
where they strike upon the walls of the glass tube
Diag. 28.—Crookes’s Tube. Platinum made Red Hot by Impact.
the latter is made luminous with a phosphorescent
glow, and may be made red-hot, and so softened as
to bring about a collapse of the tube. These tubes are
known as Crookes’s Tubes, and their phenomena are
extremely interesting from the insight they give into
the behavior of matter under all sorts of conditions.
With a set of these tubes, the laws of motion, kinetic
energy, sound, heat, light, electricity, and magnetism
may be illustrated in a way unapproachable with any
other simple and cheap apparatus. The long free path,
MATTER, ETHER, AND MOTION 272
and inability to turn a corner when projected from
an electrified terminal, show the first law of motion
and inertia. The impact of the molecules may make a
wheel turn round,—an example of energy as good as a
windmill. The intermittent beats upon the sides of the
tube produce a sound, the pitch of which is the same as
that of the vibrations of the induction coil. The heating
of the tube and its contents shows the transformation
of free-path motion into vibratory molecular motion.
The luminousness of the gas, and the phosphorescence
of the tube, show the transformation of the electrical
energy into the vibratory molecular kind, at a rate
capable of affecting the eye. The phosphoresence itself
showing the conditions needed for producing it; the
origination of the motions in the tube showing the
relation of electricity to the other forms of motion
developed; the deflection of the stream of electrified
molecules by a magnet illustrating the effects of a
magnetic field upon a current of electricity. The fact
that such streams of molecules are projected from an
electrified terminal solely by impact there, is shown by
their returning to it when there is nothing in front of
it to expend their energy upon, as a ball returns to the
earth when thrown into the air, which is the case when
but one terminal is connected with the induction coil;
and, lastly, such a tube will be lighted up by being
ELECTRICITY 273
merely in the neighborhood of an induction coil, or
rather in a varying electric field. They may be insulated
and several feet away from such induction coil or a
Holtz or other similar machine and yet be internally
lighted every time a spark passes, which shows that
the luminousness seen in the tubes is not necessarily
due to any electrical current present, because in this
case there can be no electrical current.
THE NATURE OF ELECTRICITY.
There have been many theories proposed to account
for electrical phenomena, yet to-day there is no one
that is generally held, even as a provisional one, among
physicists. Some have even abandoned the hope of
mankind ever being able to reach a consistent theory of
it. The case has been the same in the history of heat,
of light, and of magnetism; yet text-books of to-day
do not hesitate to state what is the nature of each
of these. Electrical phenomena have greater variety,
and the apparent dual character oftentimes present has
served to give a perplexing degree of complexity to
them. The writer has thought that a summation of
the principal factors present in electrical phenomena
might be helpful to some in their endeavor to find
some physical explanation without having to assume
MATTER, ETHER, AND MOTION 274
something sui generis, which has no other necessity for
being except the very dubious one of accounting for
a certain phenomenon. Caloric, light corpuscles, and
vital force were such visionary creations; but further
knowledge has enabled science to dispense with all of
them, leaving nothing in their places but what was
known to exist before; namely, matter, ether, and their
motions. Such a steady course of reduction to these
factors leaves one with the fair presumption that it will
likely fare the same way with any other agencies that
have been imagined to account for phenomena, though
the latter may, for the time being, seem not reducible
to simple mechanics.
There are certain a priori reasons for thinking that
in electrical matters, as in all other physical agencies,
only matter, ether, and motion are concerned. No one
has ventured to identify ordinary matter and electricity,
which cuts down the possibility to one of the remaining
two.
If it be admitted that matter is not altered in quantity
by any process to which it may be submitted, and also
that the amount of ether and energy in the universe
are constant, it follows that all the different phenomena
exhibited by matter are due to the different kinds of
motion it may have; for motion is the only variable factor.
On such a premise one can fairly maintain that no
ELECTRICITY 275
matter how obscure and puzzling a phenomenon may
be, its explanation lies altogether in its characteristic
motions, and, when they are fully made out, there
will be no more to learn about it. If so much be
granted, one has got on a long way towards the final
answer to the questions, What is the nature of heat?
what is the nature of light? what is the nature of
electricity? Two of these are settled, and no one thinks
of asking as to their nature. The nature of heat was
settled by Rumford and Davy, that it is a form of
motion in matter. The nature of light was settled by
Young and Fizeau, that it is a form of motion in
the ether. What remained to be done was simply to
discover the particular kind of motion in each case.
Spectrum analysis and photography have since given
us the particulars. Electricity is on precisely the same
philosophical basis; and, in the absence of evidence
of the existence of some other physical factors than
matter, the ether, and motion, one would be entitled
to the philosophical opinion that electricity must be some
form of motion. What the particular form is may be a
subject of investigation, but not the nature of it.
It is my purpose to show, first, that in every case
where electricity is produced motion of some sort
is antecedent to its production; second, that in every
case the effect of electricity is to produce motion of
MATTER, ETHER, AND MOTION 276
some sort, and that itself is annihilated in doing it in
precisely the same sense as motion of any other sort
is annihilated when it is transformed.
1. As to its origin. When the face of the thermopile
is heated and electricity is produced, we know that
vibratory molecular motion is the condition for its
appearance.
In a galvanic battery the molecular exchanges by
which zinc is dissolved and oxidized, and hydrogen is
set free, are well known, and also the heat equivalent
of such re-actions; and they are measured in heat
units, which in turn may be made the measure of the
electricity developed.
When glass or wax or other substance becomes
electrified by friction, the word itself expresses the
condition necessary for producing it. Mechanical friction
is the antecedent.
When a conductor is moved in a magnetic field and
becomes electrified, the effect depends absolutely upon
the motion. Stop that and all evidence of electricity
disappears.
The same thing is true when electricity is developed
by so-called induction in a field produced by a
neighboring body that is electrified in any way. The
continuous production of it implies continuous motion
of one or the other body.
ELECTRICITY 277
In dynamos of every variety of form the mechanical
motion turned into them is the antecedent, and the
energy of the engine spent in turning the dynamo has
its full representation in the electric energy developed,
and when there is no motion there is no electricity.
In the physiological development there are always
chemical, thermal, and mechanical motions, which are
spent to produce what electrical phenomena appear,
whether in mankind or in animals.
In the air and in the earth there are changing temperatures,
condensations, etc., which signify molecular
motions.
Some crystals, like tourmaline, become electric by
heating; some, like mica, become electric by splitting;
and so on. Every one implies that some kind of motion
has to be spent to develop the electrical condition, and
in each case the particular kind of motion that has
been spent to produce it has been spent; that is, it has
been transformed in the same sense that the translatory
motion of a bullet has been transformed into vibratory
when it strikes the target. The electricity thus appears
as the representative of the kind of motion that has
been destroyed.
Some have imagined that electricity was a kind of dual
matter, which was broken up by the various processes
described, or that some substance was transferred from
MATTER, ETHER, AND MOTION 278
one place to another, so that there was more than the
normal amount in one place and less in another. Even
such conceptions do not get rid of the idea of motion
being the chief characteristic, for the separations are
the ideal embodiments of motion, and in this case the
measure of it; so nothing whatever is gained, either in
clearness or simplicity, by such invention.
2. The effects of electricity are to bring about mechanical
motions of some sort.
The stress into which the ether is thrown by either
an electrified or magnetized body is a change of
position of adjacent parts with reference to each other,
and the fact that this stress travels with the velocity
of light shows that motion is the essence of it. The
re-action of the stress in the ether upon other matter
in it always results in the motion of the latter. If the
whole body can move, it will do so, and mechanical
motion is the immediate effect. If it cannot move as a
whole, its molecules are twisted into new positions, so
that motion, either molar or molecular, is the result.
As the electric current in a conductor always heats
the latter in every part, one has but to reflect upon
the character of heat motions to perceive that some
kind of motion must be the antecedent of it. Consider
a short portion of wire through which a current of
electricity flows. It becomes warmer and now radiates
ELECTRICITY 279
faster into space. It is losing motion by imparting it to
the ether. Trace back the ancestry of the ether motion,
and it appears as vibratory motions of the molecules
of the conductor, thence as electrical current, thence as
armature rotations of a dynamo, thence to the engine
movements, thence to the furnace and the chemical
re-actions going on there. There is no question as to the
nature of the factors in all of these but one. Call the
chemical re-actions A, the engine B, the dynamo C, the
electricity D, the heat E, and the ether waves F. With
the exception of D, each one is known to represent
a certain kind of motion, molar or molecular, and all
in a consecutive series. Is it not difficult to conceive
that the step D can be anything different in character
from the rest of the series, and, whether understood
or not, must represent some phase of motion? To
think otherwise is to think that motion can have some
other antecedent than motion. Whoever sets himself
in earnest to this problem will see there is but one
answer to it.
So heat effects, light effects, chemical effects, as well
as the direct mechanical ones shown in Crookes’s Tubes,
or otherwise, will lead to precisely the same conclusion
that electricity represents an intermediate molecular kind of
motion, having definite motions for its antecedent, and
definite motions for its consequent, and so must itself
MATTER, ETHER, AND MOTION 280
be some peculiar form of motion, differing from the
others as they differ among themselves, and nothing
beyond that. It may also be remarked that every form
of motion which is capable, under definite mechanical
conditions, of developing electricity, electricity is itself
capable of producing. The processes are all reversible.
If heat will produce electricity, electricity will produce
heat. If chemical re-actions produce electricity, electricity
will produce chemical re-actions, and so on of all
the rest; so if they be reducible to motions, so must
electricity.
Such considerations make logically certain what the
nature of electricity is; but they do not indicate what
the character of the motions is that gives it identity,
and distinguishes it so radically from other well-known
kinds of motion. In the chapter on “Motion” it is
pointed out that there are three fundamental kinds
of motions,—translatory, vibratory, and rotary,—and
that with these all the various complicated motions
of mechanical processes may be produced. It is also
pointed out that for convenience we call those motions
mechanical that are on a scale of visible magnitude,
but such as cannot be seen are called molecular and
atomic. It is plain, in this case, that the motions must
be on a molecular scale, for no motions are directly
perceived in electrical phenomena any more than in
ELECTRICITY 281
heat phenomena; so there remains for consideration
what evidence there is for the motion being molecular
and therefore of matter, or of the ether.
It appears that when certain kinds of work, such
as friction, are spent upon a mass of ordinary matter,
electricity is developed, and we say the body is
electrified. The body in this condition at once re-acts
upon the ether about it; and it has happened that
some persons have given most attention to this effect
of the electrified body, and the phenomena that may
result from it, and have called it electricity; while
others have given more attention to the condition of
the matter that induced the ether stress, and they
have called that electricity; while the greater number
have hopelessly confused the two, calling both by the
same name, just as formerly heat and ether waves
were both called heat. It is plain that a physical
condition of things in matter requiring a name ought
not to be designated by the same term as that physical
condition in the ether which is the result of the first.
One is, therefore, justified by the logical necessity of
making a distinction, in adopting the name electricity
as applicable to one and not the other, and also in
calling the phenomenon in matter by that name and
denying its applicability to any effect of it wherever
it is plain there has been a transformation. Thus it
MATTER, ETHER, AND MOTION 282
would be as illogical to call ether waves set up by
an electrified body electrical waves, as it would be to
call the swinging of a pendulum that was actuated by
electrical attractions electrical vibrations.
We are, therefore, now reduced to the sole consideration
as to the character of those molecular motions
which differentiate electricity from heat and free-path
motion; and here the apparent dual character, which
has been so puzzling, helps at once to an understanding
of it.
For many years it has been merely a matter of
convention that a current of electricity is said to move in
a certain direction in a wire. It has often been noticed
that there is an apparent current in both directions
from any electrical source; and one has been called
a positive, the other a negative, one; yet the current,
reckoned either way from its source, is always the
same at a given point, and has not unfrequently been
considered as made up of two currents moving in
opposite directions.
If one will take a limp rope a few feet long and tie
its ends together so as to form a ring, and, holding it
in his two hands, will begin to twist it in one direction,
he will see the twist start in opposite directions at his
hands, and each one can be traced quite round the
ring, neither interfering with the other; yet one is a
ELECTRICITY 283
right-handed twist, the other a left-handed one; and
one might call one a positive and the other a negative
current. There will be as much twist in one part of
the rope as in any other, and the rate of rotation
at the hands will be the measure of the amount of
motion, and, consequently, of the energy that is in the
circuit. For a rope substitute a wire, and for the hands
a battery or a dynamo, and the analogy is complete,
except that no rotation is seen in the wire as a whole;
so, if there be rotations, they must be of molecules
and not of the mass. Molecular motions must, of
course, be inferential. It is so for heat. The waves
called ether waves imply vibrations of matter; and, if
there be any known rotary motions in the ether, they
would imply molecular rotations for the same reason.
It is conceded that in every electro-magnetic field the
ether is in a rotary motion, and in numerous books
it is pictured as a whirl both about a magnet and a
wire carrying an electric current. The rotation of an
electric arc in a magnetic field shows it, and the twist
given to a polarized ray of light in passing through
it also shows it; and it has been so interpreted for
years. The twist given to a conductor through which a
current is flowing, which has been before alluded to,
also gives direct evidence of the same condition; so the
phenomena confirm the conjecture that the phenomenon
MATTER, ETHER, AND MOTION 284
in matter which is called electricity is a phenomenon of
rotating molecules, in the same sense as the phenomenon
called heat is a phenomenon of vibrating molecules.
If the atoms in molecules, and the molecules
themselves, were absolutely fixed in position so as to
have no individual freedom of motion, there could
be neither vibration nor rotation; but the vibrations
tend continually to separate them, and hence between
impacts there is freedom for rotary slip, if there be
any tendency to do so. In an electro-magnetic field
the ether stress re-acts upon molecules in it so as to
rotate them upon some axis tending to set them in
certain position with reference to it. This action will
be stronger upon an atom or molecule immediately
adjacent to an electrified molecule than to one more
distant, and one may therefore infer that the process
called conduction, where heat is the immediate effect
of an electric current, is really an induction effect, and
depends directly upon the ether rather than upon the
direct mechanical effect of one molecule upon another;
for such mechanical action would make the rotation of
adjacent molecules to be opposite in direction, whereas
in an electric current all are in one direction. There is,
therefore, impact and slip, impact and slip; each impact
knocking the molecule out of the position the induction
had set it in, and each arrest of the slip resulting
ELECTRICITY 285
in increasing the amplitude of vibration, and hence
raising the temperature of the conductor. Hence, the
explanation of the transformation of electrical energy
into heat energy. An electric current is, therefore, not a
simple phenomenon, but is considerably complicated,
involving motions of both molecules and the ether;
the molecular motion depending directly upon the
re-action of the ether stress produced by an adjacent
molecule rather than upon mechanical contact. The
electrical condition called static being itself a compound
of abnormal molecular position and stressed ether, is
the condition which, while being propagated in a
conductor, constitutes an electric current, propagated in
the ether, constitutes an ether wave.
MATTER, ETHER, AND MOTION 286
CHAPTER IX
Chemism
The atomic theory of matter was held in some form
by ancient philosophers, but the reasons they assigned
for their opinion were not such reasons as have led men
of the present day to adopt that theory to the exclusion
of all others. Modern chemical analysis enables one
to reduce compound substances to their elementary
forms, and out of those to build up numerous other
substances with entirely different qualities. Each such
elementary form can be isolated, its properties can
be studied, and by compounding them one can at
will produce thousands of substances, each with its
own distinctive qualities. Some of the more thoughtful
men of all ages have pondered upon the fundamental
questions of physical science, and they have guessed
how it might be: some guessed this way, some guessed
that, and none of them gave a sufficient reason. It
would be very remarkable if, among a multitude of
guessers, some did not guess nearer right than others;
but such lucky guessing hardly entitles one to the
honor of being the founder of a philosophy that had
CHEMISM 287
to wait for later men and entirely different methods
to substantiate it. And this is the real state of the
case in nearly all departments of knowledge. Ask
any chemist to-day why he holds the atomic theory
of matter, and he will reply that he can isolate the
elements, and by no process yet discovered can they
be more finely divided; that he can measure their
individual magnitude and weigh them, prove their
existence in the sun and stars; so that the weight of
evidence is exceedingly great. He will never think of
assigning any such reasons as the early philosophers
gave for their teaching. Many of the properties of
bodies of visible magnitude depend upon the number
and arrangement of the molecules that compose them,
but the properties of atoms are fundamental and not
subject to change. All substances are identified by
means of their properties, and the chemical properties
of atoms are among the most important. Not only
do atoms combine together in groups called molecules,
consisting of two or more atoms, but they combine
in definite proportions by weight, and only so; and
these proportions are called the atomic weights of
the elements, and are known for all of them; so
that molecules are compounds of definite constituents,
definite weight, and possessing definite properties. For
instance, water is made up of hydrogen and oxygen,
MATTER, ETHER, AND MOTION 288
two parts by weight of hydrogen and sixteen of oxygen;
and as to its properties, such as density, specific gravity,
conditions at different temperatures, etc., all are familiar
with. Most of these properties of bodies are called
physical, but by chemical properties is meant the ability
of atoms to enter into definite combinations with other
atoms, to form new compounds and develop new
properties. The chemist is concerned with such atomic
exchanges, called re-actions, and notes the conditions
under which they take place, and some of the new
qualities that appear, such as its physical condition,
as to being a solid, a liquid, or a gas at certain
temperatures, its crystalline form, if it has any, its
behavior with polarized light, and so on.
Underneath all chemical re-actions there lies the
question as to why atoms combine at all. At first it
was explained as due to an attractive force,—chemical
attraction, possessed by all atoms, but in different
degrees by different elements. When it became known
that this acted in definite selective ways, it was called
chemical affinity, but was still supposed to be a peculiar
force unrelated to other forces supposed to exist, such
as heat, light, electricity, and so on. In the progress
of knowledge, it became apparent that these latter
phenomena were so directly related to each other that
they were capable of being transformed one into the
CHEMISM 289
other, and then the expression “correlation of forces”
began to be used. A further analysis showed them to
differ from each other chiefly in the character of the
motion involved in the phenomena; and so forces, as
such, have been banished from physical science, leaving
not even a single primal force; for as each one can be
changed at will into any of the others there is simply
a closed chain of phenomena, no one of which can be
called an elementary one more than any other.
Chemical phenomena have been found to be a part
of the same grand division, and the term “chemical
affinity” has itself been in a measure supplanted by
the term “chemism,” which is now used to signify
the quality possessed by atoms to enter into definite
combinations; and its explanation is to be found by
noting the factors present when atomic and molecular
exchanges take place, and these have been found to be
all physical without exception. There is a large field
known as chemical physics with which one needs to
be acquainted in order to understand simple chemical
operations; namely, the effects of heat, light, and
electricity in bringing about chemical changes.
When hydrogen combines with oxygen to form water
the process is called a chemical one; but, as has been
pointed out in the subject “Heat,” there is a definite
amount of heat given out by the combination of a
MATTER, ETHER, AND MOTION 290
definite amount of the elements; and in like manner
the dissociation of the elements in water requires the
expenditure of energy proportionate to the amount
decomposed. This too is called a chemical process,
but the conditions for doing either are purely physical,
depending absolutely upon heat. The elements cannot
combine when heat cannot be given out, and cannot
be separated except by an equal expenditure. What is
true for this example is true in degree for all other
chemical re-actions; physical energy is involved in every
change and is the condition for the change. The first
law of thermo-dynamics states the quantitative relation
between heat and mechanical work; viz., that it is
measurable in foot pounds, and is equal to 772 foot
pounds per pound degree, and this is called a heat
unit. Now, the chemical combination of a pound of
hydrogen with oxygen gives 61, 000 heat units, and is
therefore at once measureable in foot pounds, showing
a direct relation between chemical re-actions and heat
or work.
It has also been discovered by experiment that in
the absence of heat chemical re-actions cannot go on,
and this has led chemists to the conclusion that at
absolute zero chemism does not exist. There is not
only no selective action, but no cohesion among atoms,
and all molecules would fall to pieces—that is, to
CHEMISM 291
atoms, quite dissociated—at absolute zero. Instead of
requiring 61, 000 heat units to dissociate a pound of
hydrogen from water, it would not require any, for if
the atoms do not cohere, no work would need to be
done in order to separate them.1
From this, then, it appears that chemism is determined
by heat, and does not exist in the absence of temperature.
When it is developed it manifests itself in selective
ways, and in the formation of definite compounds; and
it therefore is a proper subject of inquiry as to how the
temperature of atoms can give such selective qualities to
them. This requires a reconsideration of the distinctive
quality of heat itself. It has been pointed out that this
consists in the internal vibratory motions of atoms and
molecules, as distinguished from translatory and rotary
motions; that the evidence for this comes, first, from
the fact that a body of any size possessing any degree
of heat—that is, having a temperature above absolute
zero—is constantly exchanging its energy with the
ether, and that the rate of the exchange depends upon
the temperature; and, second, that translatory motions
of bodies in ether do not require the expenditure
of energy, or, in other words, that for such motions
the ether is frictionless. This is the same as saying
1See Appendix, p. 477.
MATTER, ETHER, AND MOTION 292
that, where the heat of a body is lost by radiation,
it is the internal vibratory motion alone that is lost,
not its translatory velocity. Consider a body of any
magnitude whatever, having any temperature whatever,
and moving at any assignable velocity in space. After
an interval it will have lost some of its temperature
by radiation, and, if it moves long enough, it might
lose it all, reaching absolute zero; but its translatory
velocity will not therefore be reduced in any degree.
Hence, in considering the heat in a body, independent
of any other motions it may have, one has only to
do with its internal vibratory movements, and that the
temperature of a body, say an atom, is measured by
the amplitude of its vibration, and is proportional to
the square of that amplitude.
If, therefore, chemism is directly related to heat, one
must attend to what must be going on in an atom,
not groups of them.
To say that an atom vibrates is to say that it is
changing its form, and to explain how changing its
form can result in such selective properties as atoms
exhibit is to explain chemism by the mechanics of
the motion involved. Whether atoms have one form
or another will make no difference in this argument,
which is that the result is due to change of form,
whatever that may be; but, for making the subject
CHEMISM 293
mechanically clear, some form may be adopted, and
one can do no better than to choose that form which
now has most probability in its favor judged by other
phenomena; that is, the vortex-ring, which has been
treated under the head of “The Ether.”
When such a body vibrates in its simple way it
elongates alternately on two axes at right angles to
each other; that is, the change in form is from a circle
to an ellipse, so as to assume first a horizontal, then
a vertical elliptical form, as shown in the cut. Such
Diag. 29.
changes are due to the elasticity of the
ring, and are brought about in such
an atom by impact, by friction, and by
absorption of ether waves. Whether
produced in one way or another, they
represent absorbed energy and exhibit
it as heat, the temperature of a given
one depending upon the amplitude
given to it by a definite amount of
energy however applied.
Such changing forms imply nodes and loops in the
vibrating body, positions of minimum and maximum
motions; and when the vibratory rate is the fundamental
one,—that is, the lowest rate the body can have,—there
will be four of each, the nodes being the positions of
minimum change of form. Such nodes may be seen in
MATTER, ETHER, AND MOTION 294
vibrating bodies of all sorts,—strings, bells, rods, pipes,
and rings. The size of a body makes no difference in
this characteristic, and it therefore may be affirmed of
atoms as well as of any other magnitudes.
Diag. 30.
Let it be admitted that vibrating
atoms can cohere for any reason,
it will be seen that an atom such
as represented could only have
other atoms attached to it, and be
in a stable condition, when they
were at the nodes; and in this case
four might be so attached and no
more, if they were approximately
of the same size. Such places in
atoms might be called bonds: they
would be definite in number, position, and strength.
If the other attached atoms were themselves vibrating,
they would each have their own nodes; and if they
were free to turn into any position, one might be sure
that the nodes of each would be in contact, and that
the loops of the vibratory motions would be where
space to move in without interruption was free. Such
a combination of atoms might be called a molecule.
It would consist of a definite number of atoms, each
with its own atomic weight; and if the strength of
the cohesion depended upon the vibratory motion, it
CHEMISM 295
Geometrical Forms of Snow Flakes.
MATTER, ETHER, AND MOTION 296
is easily seen that when there was quiescence in that
there would be disruption or dissociation. Moreover,
Diag. 31.
Diag. 32.
when there was such a nodal bond it would be like
a hinge, and two thus united could swing upon it;
while if three were thus united and two were to swing
upwards, they would meet at a node on each and stick
together for the same reason the other nodes did, thus
forming a symmetrical and stable figure against which
other similar ones could be built up, node against node
indefinitely. A hexagonal figure would result. If four
were attached to the primary nodes, and each was to
swing up ninety degrees, there would be formed a
sort of cubical box without a lid; but at the top will
be presented four open nodes, upon which the four
nodes of any other similar one might be placed: and
CHEMISM 297
thus could a cubical structure be built by addition of
similar forms indefinitely. Such symmetrical forms are
called crystals.
Of course all this presupposes that there is some
good mechanical reason for atomic cohesion, that is in
some way dependent upon temperature; and to make
this clear it is needful, first, to call to mind some
phenomena of a similar sort on a larger scale.
It is well known that if a light body be brought near
a vibrating tuning-fork, the latter acts as if it attracted
it, for the light body will move towards the fork. The
same thing is true of other vibrating bodies, and the
explanation is that the vibratory motion reduces the
pressure about the body. Thus, suppose the hand to
move to and fro; as it moves forward the air in front
of it is somewhat condensed, while that behind it is
partially rarefied; when the hand returns the same
thing happens. The air follows up the hand because
the pressure is reduced next the hand, and if the
hand could swing back and forth, faster than the air
could return to it, there would be formed a perfect
air vacuum; and that means that the pressure would
be nothing at the hand and fifteen pounds per square
inch at a distance from it. Hence any body placed near
the hand would be subject to a pressure greater on its
remote side than on the side adjacent to the hand, and
MATTER, ETHER, AND MOTION 298
would be pushed by it towards the hand. This would
be a phenomenon similar to attraction, the movement
towards the vibrating body being due directly to the
pressure of the medium, while the difference in the
medium would itself be directly due to the vibratory
movement. The amount of such difference in pressure
is evidently determined by the degree of vibration.
Now, if one can imagine a similar condition of things
about an atom vibrating in the ether, he can understand
how its vibratory movements might reduce the ether
pressure adjacent to it in a way proportional to the
movement, and also how at the nodes such effect would
be at a minimum, and at the loops at a maximum, so
there would be produced what is called a field. As
the condition that produced it was one of mechanical
motion, one might call the field a mechanical field, for
mechanical effects of translatory motion result from it.
When such an effect takes place among atoms one
might distinguish it as a chemical field, for it would bring
about mutual cohesion among atoms, and the nodes
would determine the positions of stable combinations;
and a molecule so built up would require an amount
of energy spent upon it to break it up equivalent to
the energy spent, to produce the field, or, in other
words, equivalent to the heat in the atom.
It is here to be noted that when atoms combine in
CHEMISM 299
CRYSTALLINE FORMS.
The above figures illustrate very clearly the molecular arrangement in crystals of various
kinds. A represents a cross section of Brazilian Topaz, as shown in polarized light.
B is a hollow faced cube of salt, and C a similar hollow faced octahedron of copper
sulphide. They show that the cohesive strength is greater on the edges than elsewhere.
Some crystals, when being dissolved, leave a complete skeleton of themselves the last
to disappear. D is a skeleton crystal of silver from Scotland, where the structure consists
of a series of minute octahedral crystals adhering to each other in such directions
as would build up a single large octahedral crystal if filled out.
MATTER, ETHER, AND MOTION 300
this way each one retains abundant space for its heat
movements, so its temperature may be varied within
considerable limits without interfering with molecular
stability. And, if the vibratory movements continue,
then each molecule will have its own field, which will
be the resultant of all the fields of the atoms that are
combined thus to make the molecule. The field of a
molecule will then have a form which will depend
absolutely upon the number and arrangement of the
constituent atoms, and will extend to some distance in
space beyond the geometric boundary of the molecule
itself.
The presence of such a chemical field must affect
other chemical fields in the neighboring space where the
fields overlap, hindering or facilitating the exchange of
atoms in other molecules, because lessening the pressure
holding them together. There are many examples of
this kind of action known. It is called catalysis, which
signifies the action of a given substance in bringing
about chemical reactions without itself being changed.
For example, the binoxide of manganese, when mixed
with the chlorate of potash, greatly facilitates its
decomposition by heat, though the binoxide is itself
not decomposed. Pure zinc is dissolved with difficulty
by sulphuric acid; but a little mercury or iron, or other
so-called impurity, enables it to be dissolved freely.
CHEMISM 301
Hydrogen and oxygen gases will not combine when
simply mixed; but a little spongy platinum placed in the
mixture will at once bring about the combination, but
will itself suffer no chemical change. These gases will
also slowly combine in the presence of mercury when
kept at the temperature of 305. In glass vessels without
the mercury no combination at that temperature occurs,
but on raising the temperature to 448 it combines very
slowly. In smelting operations a flux has a similar
function, and in some cases the boundary line of such
action can be observed. Some re-actions take place at a
different rate near the sides of the vessel that contains
the solution than away from it, and some mixtures of
substances in solution will separate from each other
except within a short distance from the surface. Such
phenomena show that the mere presence of some
substances is sufficient to profoundly affect chemical
re-actions. The chemical field of substances gives a
consistent explanation of catalysis. There is another class
of phenomena well known, but hitherto without any
rational explanation; viz., some supersaturated solutions
seem unable to initiate the process of crystallization,
but the smallest crystal of the substance starts it, and
the whole body is solidified in a few seconds. Here
it is evident that the crystal, taken as a nucleus, had
a field that compelled other and similar molecular
MATTER, ETHER, AND MOTION 302
groups to arrange themselves in similar order. This
is a phenomenon of such importance as to warrant
some attention here. When two tuning-forks having
the same pitch are separate from each other a distance
of several feet, and one of them be made to produce a
sound, the other one will be made to sound likewise
by the action of the sound waves in the air upon
it. The effect is called sympathetic vibration. Other
forks having different rates of vibration will not be
similarly affected, so the vibrations in the air select
out the particular fork having the same rate as the
one vibrating, and cause it to enter into a similar
state of vibration. So it appears with a magnet. Any
magnetic bodies in its field become magnetized there;
that is, they are brought into the same physical state
as the body that incited the field. Such physical fields,
then, are capable of compelling bodies in them to
assume the same state of motion or similar position,
or both, as the body that produced the field, provided
the substance itself be constituted molecularly like the
first,—and this simply by being in proximity, not by
contact. It is a kind of induction, common through
the whole domain of physics. In the organic world of
living things the phenomenon of growth is manifested
by what are called cells, which are symmetrical groups
of molecules, as crystals are, only much more complex.
CHEMISM 303
Growth consists in the formation of similar cells out
of suitable molecular constituents in the neighborhood.
Each different part of a plant or animal has a different
cell structure. If, therefore, it be conceded that each
cell has a field, which is the resultant of all the
elements that make it up, it will be seen how such field
must act upon other matter within it, compelling it to
assume a form similar to the cell that produces the
field; that is, to form a similar cell adjacent to itself.
Such formation is called growth; but the similarity in
form and function, when appearing among plants or
animals, has been considered as due to heredity, a term
that has a definite enough meaning, but which has not
been supposed to be due to mechanical necessity but
to some super-physical agency not amenable to purely
physical laws and conditions. It is possible to pursue
this much further and to show that cell structure itself
may be modified by molecular fields, and how stability
of form and function are possible with some and not
with others,—how what in natural history is called
variability, reversion, and other phenomena of the sort,
are explicable as due to the same factors that organize
atoms into molecules, and molecules into crystals.
Every one interested in the fundamental questions of
chemistry will be able to follow out in many ways the
mechanical conceptions here introduced, and compare
MATTER, ETHER, AND MOTION 304
what he knows of chemical re-actions with them. It
will be especially helpful for one to draw upon paper
such ideal atomic rings with their edges touching, and
marking where the nodes must be. Such diagrams as
the one on p. 294, fig. 30, thus drawn, cut out, and
the parts bent up until they touch each other, will
probably surprise one at first to find how the nodes
will be brought adjacent to each other and therefore
into a stable position.
So far it has been assumed that there will be in the
ether about a vibrating atom an effect comparable with
the effect produced in air about a tuning-fork or other
vibrating body that is producing sound waves. One
might be satisfied that there was such an action, even
though he were not able to explain it, provided there
were good reason for the assumption. The case is the
same as for a magnetic field within which magnetic
phenomena take place, though a magnetic field cannot
be isolated. It is the same for the existence of the
ether itself: it is inferential, but from a large body
of phenomena of different sorts, all corroborating the
hypothesis; so one is satisfied. When a magnet acts
upon a piece of iron not in contact with itself, we
explain the action by the magnetic field; and, if a body
acts chemically upon other bodies not in immediate
contact, controlling their motions and positions, as is
CHEMISM 305
the case, the same kind of an assumption is to be
entertained. If a reasonable explanation for the existence
of the field can be offered, all the better, though no
one holds more lightly upon a magnetic field because
he cannot explain it. In the chapter on magnetism it is
remarked that there is good reason to think that atoms
of all kinds are magnets. If that be the case, then
every atom has a field of its own, wherever it may
be; and it would seem likely that this magnetic field
of atoms was the underlying factor in the so-called
chemical field; and it is therefore well to analyze the
phenomena, having that magnetic field in mind.
A single magnet of any form will have its field under
all conditions, and the shape of the field will be determined
by the form of the magnet. If the magnet were of sufficient
size, there would be no difficulty in locating it by its
field, even though the magnet itself could not be seen.
A number of magnets arranged promiscuously would
so neutralize each other’s fields as to have no residual
field, and in order to detect the existence of magnetism
it would be needful to get very close to an individual
magnet. When a steel magnet is dissolved in an acid
all evidence of the existence of magnetism disappears,
for the iron molecules are now separated from each
other and are scattered promiscuously through the
solution. Any disturbance whatever that disarranges
MATTER, ETHER, AND MOTION 306
the magnetic arrangement of molecules destroys the
evidence of the magnetic field, except at very short
distances. When a piece of iron is heated to redness it
cannot be made magnetic in the ordinary sense; for the
vigor of the vibratory movement continually knocks the
molecules into new positions, and therefore changes
their resultant fields, leaving but a neutral effect upon
outside bodies.
As chemical re-actions take place in liquids or
gases, and only exceedingly slow in solids, it follows
that in them one has to deal with molecules in all
positions,—that is, an entirely disordered arrangement,
and such as would exhibit no evidence of magnetic
field, even though every atom was itself a strong
magnet; and this condition of neutrality would be
constant so long as the temperature kept up so much
mechanical disturbance as to prevent any systematic
arrangement. Yet it is to be borne in mind that the
magnetic field of no one has been destroyed: it is as
strong, as far reaching, as ever; but it is masked by
overlying fields,—that is all. Let any one of them suffer
any change at all, and the effect of it would be felt
throughout the whole space the field would occupy if
there were no other one in its neighborhood.
Now, when the form of a magnet is changed, it
changes the form of the magnetic field—that is, the
CHEMISM 307
distribution of the stress that constitutes the field; and,
when an atomic magnet vibrates, it is changing its
form; and as a result its field is changing at the same
rate. A multitude of such independent magnets, all
changing their forms and fields, would be sending
out waves into the ether; but they would be caused
by and measured by their heat motions, not by their
magnetic condition simply; and the effects of these
waves at a distance from their source would be practical
uniformity unless the waves were very long. For such
short ones as are produced by atomic and molecular
vibrations there could be no ordinary indications of a
magnetic field such as are exhibited in the movements
of bodies of visible magnitude. Long waves of precisely
the same sort caused by motions of a slower rate
might make magnetic needles move. Thus, magnetic
needles upon the earth have been observed to move
at the same instant that solar disturbances have been
witnessed through a telescope, which indicates that the
waves were long ones, giving a magnet time to move
one way before it was impelled to move in some other
way.
This condition of practical neutrality on account
of the rapidity of the change at a distance from the
magnetic body would not hold true in close proximity
to the body itself; for the changes in the field will not
MATTER, ETHER, AND MOTION 308
only be actually greater there, but the fact that there are
nodes and loops necessitates changes in the stress at
the surface of the atom, and renders it possible for the
actual magnetism to assert itself and act upon another
very near to it which it cannot have in any degree a
little farther away, the actual distance being comparable
with the diameter of the atom itself. Hence, atoms
close by would have certain magnetic effects upon each
other in the nature of selective effects, on account of
the uniformity of the stress at the nodes, and the
number of nodes would determine the possible number
of cohesive attachments. So one may fairly presume
that the vibratory motions such as constitute the heat
motions of atoms are the physical conditions that
underlie chemical combinations and give to them their
quantitative character, their selective property, and their
symmetrical form into which they arrange themselves.
This gives a rational account of so-called chemical
attraction, and makes it clear how the laws of thermodynamics
are related to chemical re-actions. It reduces
the whole scheme to one of the mechanics of vibrating
magnets; and the evidence that atoms are such magnets
does not rest upon the necessity of the conception for
the hypothesis, but upon much confirmatory experiment
that has led physicists to the conclusion that they
are such, in a manner quite independent of what
CHEMISM 309
phenomena might be deducible from matter with
such a constitution. In conclusion, it may be added
that, although the idea of ring-formed atoms has been
adhered to in this explanation, it is not to be understood
that the same explanation would not apply to atoms
constituted in any other manner; for all that is implied
in the above is that whatever their form and substance
they are magnets, and that they are so elastic as to
be capable of internal vibratory movements—that is, of
changing their forms in a periodic way; and of this
there appears to be no reasonable doubt. When several
such are combined together the resultant motions and
their effects become very complicated, and therefore
difficult to disentangle; but that would be no reason
for not holding a well-grounded conviction that all
chemical phenomena are truly physical, and referable to
fundamental mechanical laws, and are fully explained
when these mechanical conditions are pointed out.
MATTER, ETHER, AND MOTION 310
CHAPTER X
Sound
The term “sound” has two very different significations,—
one a physiological one referring to a sensation
in the organ of hearing, the other the physical cause of
the sensation. When one has the sensation of sound,
of course he usually infers that it was caused by
some external physical condition that has in some way
impressed itself upon his auditory apparatus; and, to
one who has thought but little about it, it is difficult
to get rid of the idea that sound is a something which
exists, whether it be heard or not. That is, there
would still be sound though there were no ears, that
a tumbling pile of books in a deserted house would
make a racket if no one did hear it. On the other hand,
one may call that sound which is capable of being
heard; and when those conditions are investigated it is
found, in all cases, to be some kind of a mechanical
impulse, or succession of impulses, generally in the air,
which may be traced from the ear to some body which
is found to be in a state of vibration. The latter is
called a sounding body, and the air is called a sound
SOUND 311
conductor; but these conditions are not necessary for
the sensation of sound. One may not infrequently
hear what is called ringing in the ears, that has its
origin within the head, and, perhaps, in some cases
independent of any of the auditory apparatus, like
some nerve disturbance even at the base of the brain
itself. Hence there is a distinction between hearing and
the cause of hearing, and the latter does not necessarily
imply anything external to the listener. One may be
deaf so that no conditions external or internal will
produce the sensation. As the sensation itself can give
no infallible testimony as to what causes it, it has
come about that the physical conditions which may
be heard as sound have been investigated, and the
science of sound, or acoustics, has been developed quite
independent of the sense of hearing, the latter being
only a convenient instrumentality in the investigation,
not an indispensable one. In this sense sound is the
science of the vibratory movements of elastic bodies,
and one may inquire first as to the origin of such
movements. When one body strikes upon another,
motion is imparted to the latter. If enough motion is
imparted, it may move visibly, and we then call such
motion mechanical. Though it does not visibly move,
yet energy has been spent upon it in some degree, and
must be represented by some degree of motion which
MATTER, ETHER, AND MOTION 312
at first it did not have. If a pencil be struck upon the
table, one may be as sure that energy has been spent
upon it as if it had been struck with the fist, only less
in amount.
When molecules are compressed together so as
to increase the density, and retained in such closer
compactness, heat is always the result; that is, the
molecules themselves have their amplitude of vibration
increased: but when molecules are compressed quickly,
and the pressure be as quickly removed, the compressed
molecules at once rebound to their original position with
a velocity that depends upon the degree of elasticity
the body has, and, like a swinging pendulum, do not
stop at once when they have reached that position, but
go beyond a little, and thus oscillate back and forth.
Each molecule pushes against its neighbors, and they
upon theirs, and so on, the motion travelling outwards
from the point of disturbance in every direction, with a
velocity that is proportionate to the temperature; that is,
the vibratory rate of the molecules themselves, which,
as pointed out in the chapter on heat, is exceedingly
great.
This particular kind of movement is called longitudinal;
that is, it is to and fro in the direction in which
the disturbance travels, and depends altogether upon
the properties of the body that is struck, and not in
SOUND 313
any degree upon the initiating cause. When the table
is struck with the pencil the sound heard is different
in quality from that given out by a similar stroke upon
the window or a tumbler. It differs also in duration.
The latter may continue to be heard for some seconds,
while the former is brief. Every elastic body has some
particular vibratory rate, which depends upon its size
and shape as well as the material it is composed of.
A stretched string or wire, a board, a lath, a bridge, a
house, for examples, all have individual rates of motion,
into which they can be brought by some well-directed,
sudden push. When a strong wind shakes a house, the
shake is the vibratory rate of the building, and may be
as low as one or two per second. In general, as bodies
are smaller their rate of vibration increases, until it
becomes greater than thirty or forty per second, when
the effect can be heard. Stones have an individual
pitch, or rate of vibration, so that by selection one
may get a set to represent the musical scale when
struck. Smooth bits of laths of different lengths give
out their pitch when dropped upon a table; and, with a
properly graded set, tunes may be played by dropping
them successively. The rate of vibration, or pitch, of
a table is relatively high—several hundred per second;
and a pencil knock distributed over so large a body,
and by it to the floor, reduces its strength very fast.
MATTER, ETHER, AND MOTION 314
The tumbler has its motions symmetrical, therefore of
greater amplitude, and last longer. A tuning-fork struck
and held in the fingers near the ear will be heard for
a much longer time than if the stem be held against
the table, as any one may satisfy himself by trying. In
the latter case the motions are conducted away freely,
in the former case not so freely. In the former case
the sound appears louder to the ear, because the air,
in contact with the vibrating table, receives vibratory
motions from it as well as directly from the fork; and
so the air motions are re-enforced, and the energy is
dissipated so much the more rapidly.
The idea in all this is that, so far as sound consists in
vibratory motions, energy is involved, and is distributed
in accordance with mechanical laws; the size, density,
and elasticity of the sounding body being the factors
which determine the rate at which the distribution can
go on.
If the motion be properly mechanical, any agency
that can originate such motions can give rise to sound.
One might ask himself here if it be likely that any
kind of motion, or form of energy, cannot produce
it. If it be remembered that motion is the antecedent
of motion in all known cases, one will perceive that
sound might have a variety of antecedents, as it has.
To the mechanical ones alluded to might be added all
SOUND 315
cases of percussion, impact, friction—indeed, the whole
range of mechanical motions. Any agency that can
change the form of a body can cause sound vibrations.
That heat can directly produce sound is shown by
the roar of fire in furnaces; and tubes having a burning
gas-jet in them may give out a loud sound. In these
cases it is the body of air that is caused to vibrate
energetically.
When a beam of light falls upon a body that can
be heated by it there is a re-action between the surface
and the air, in which the surface is pushed slightly
backwards, as indicated by the radiometer. If a beam
is allowed to fall intermittently upon such a surface, it
will be thrown into vibrations as if it had been struck,
and will give out a sound, the pitch of which depends
upon the number of interruptions per second. Such a
device is called a radiophone.
A current of electricity sent through a conductor
in an interrupted manner makes the wire give out a
sound. The current heats the wire, expands it slightly,
and cools as suddenly when the current is stopped;
so the succession of currents results in sound. In
like manner, a current of electricity going through an
electro-magnet causes a click at the instant of making
and breaking the current. This is occasioned by the
change in position of all the molecules. A succession
MATTER, ETHER, AND MOTION 316
of these may keep up a continuous hum.
The electric spark itself always produces a snap of
brief duration, for short sparks from induction coils and
electric machines; but, when the spark is a long one,
like a flash of lightning, the sound may be prolonged
several seconds. Along the line of the flash the air is
greatly heated for a very brief time, and it therefore
rapidly expands. The quick cooling produces a collapse
of the heated column of air, with the consequent noise.
The duration of the thunder does not signify that the
lightning lasts such an appreciable time, but that a part
of it was a distance away, and that time was taken for
the sound to come from the more distant place.
That chemical action can give rise to sound is proved
by the explosion of gunpowder and other explosives,
solid and liquid. In these cases a large amount of
gas is suddenly formed, and at a high temperature; it
displaces the air quickly and forms a great wave. One
may often feel the wave of compression produced by
a cannon go by him, even at the distance of several
hundred feet from it. These examples show that heat,
light, electricity, magnetism, and chemism are directly
related to mechanical motions because competent to
produce them under appropriate conditions. If motion
be the antecedent of any given motion, and any of
these may be the immediate antecedent of mechanical
SOUND 317
motions such as sound, what shall be said as to the
nature of each of these physical agencies?
CHARACTERISTICS OF SOUND.
As sounds may be produced by any of the physical
agencies, it does not matter, except for convenience,
what ones are adopted. Usually mechanical motions
are most convenient, and for musical purposes either
percussion, or currents of air. We speak of high sounds
and low sounds, and we find by experiment that
those called low are produced by fewer vibrations per
second than those called high. If sounds are considered
as vibratory movements, then it is evident there is
practically an infinite range of them; for there may be
any rate, from one a year or a thousand years all the
way to such vibrations as atoms make, measured by
millions of millions per second. There is no good reason
for drawing a boundary-line at one point rather than
at another, and saying that all vibratory movements
beyond this rate are not to be considered as sound,
yet it is convenient for some purposes to confine the
range to such as can be heard.
When a succession of impulses follow each other at
such a rate as just to produce a continuous sensation
of sound, it is found to require from twenty to thirty
MATTER, ETHER, AND MOTION 318
per second. It differs very much in individuals. In the
young it requires more, as the organ of hearing acts more
promptly than it does in the old. A less number than
these is heard as a tremble. From this as a minimum
one may go through a series, running from the lowest
sound produced by a piano—about forty per second—to
the highest one of about 4, 000 per second. Many insects
make much higher sounds than this. Such differences
in the rate of vibration are called differences in pitch;
and, for musical purposes, a standard of pitch has been
adopted, making the middle C of the piano give from
Diag. 33.
256 to 261 vibrations. The pitch of
a sound may be specified by giving
its vibratory rate. The pitch of
men’s voices ranges from 100 to 150
vibrations in conversation. Ordinary
whistling is produced by from 1, 000
to 3, 000 or 4, 000. The squeak of bats
is in the neighborhood of 5, 000. Beyond these figures it
is difficult to hear anything,—not because the vibratory
motions are not produced, but because they have too
little energy to affect the ear. Occasionally aurists find
abnormally sensitive ears capable of hearing sounds
with a pitch as high as fifty or sixty thousand, but
ordinary persons have a limit in the neighborhood of
20, 000; so it is customary to say that the range of
SOUND 319
hearing of mankind is from thirty per second to about
25, 000: but it should always be borne in mind that
the chief reason for not having a greater range is in
the difficulty of giving sufficient amplitude to such
very rapid changes. As the pitch rises the amplitude
decreases for a given amount of vibratory energy.
One might attribute the relatively low vibratory rate
of the maximum which the ear can perceive to the
lack of delicacy of the apparatus itself, which would
be true enough in an absolute sense; but the actual
sensitivity of the ear is really something wonderful,
for a piece of apparatus that is altogether mechanical
in its mode of operation. It has been found that the
ear can hear such sounds as are produced by small
whistles at the distance of several hundred feet; and,
if the amplitude be computed,—assuming that it varies
inversely as the square of the distance—it is found to
be comparable with the diameter of a molecule, or less
than the ten-millionth of an inch. One who understands
the necessity for vibratory motions in elastic matter
will readily conclude that between the highest number
the ear can perceive, say 50, 000 per second, and the
lowest rate capable of affecting the eye (400 millions of
millions), there is an enormous gap; and man has no
organs for perceiving the intermediate ones.
Experiments made in various ways have shown
MATTER, ETHER, AND MOTION 320
that the velocity of sound waves in air is about
eleven hundred feet per second, and varies with the
temperature, being only 1, 090 feet at the freezing point
of water, increasing or diminishing about two feet per
second for each degree above or below that; and this
is true for sounds of all degrees of pitch. If it were
not so, music could not be heard at any distance from
its source. Suppose a tuning-fork makes one hundred
vibrations in a second. At the end of the second the
first wave would have got say eleven hundred feet away,
while the last wave would have just been completed;
or between the fork and the more distant wave there
would be a series, one hundred in all, reaching eleven
hundred feet. It follows that each wave would be
eleven feet long, or the velocity of transmission divided
by the number of vibrations. The wave length of
sounds can be measured in several ways, and of course
the product of the wave length into the number of
vibrations gives the velocity of sound in any conductor.
An idea of the actual wave length for common sounds
may be had thus: If the middle C of the piano makes
261 vibrations per second, and the velocity in the air of
the room be 1, 140 feet, 1140
261
= 4.36 feet, as the length
of the air wave, and for a man’s voice it will be about
1140
125
= 9.1 feet, while the highest note on a piano will
SOUND 321
be 1140
4000
= .285 foot, or 3.4 inches. In water the velocity
is four times greater than in air, in wood about twelve
times, and in steel about sixteen times greater; and this
will give a corresponding increase in the wave length.
This velocity of sound in air is, roughly, about a mile
in five seconds, or twelve miles a minute; and at this
rate nearly a day and a half would be needed to go
round the earth.
Air waves, like water waves, are reflected when they
come against a more solid body. Such reflections of
air waves are called echoes. The mere fact of reflection
does not change the length of the wave, as the pitch of
a sound is not altered by having its direction changed.
The law of sound reflection is the same as that for
the reflection of energy in general; viz., the angle of
reflection is equal to the angle of incidence. Neither
does reflection change the velocity of sound waves.
The phenomena of echoes are familiar to every one,
for walls, houses, wood, and hills all echo sounds;
and one may roughly determine the distance to such
an echoing surface. As one approaches such surface
the time between producing a sound and its return
is shortened, until, when about sixty feet from it, the
two so blend that the echo is no longer heard with
distinctness. The sound has then travelled 120 feet.
MATTER, ETHER, AND MOTION 322
When sounds are produced at the ends of tubes the
walls of the tube prevent, by reflection, the scattering
of the waves, and the whole motion is kept in nearly
parallel lines, and with slight loss in strength; hence
the utility of speaking-tubes. If the tube be a short one,
and stopped at one end, a new phenomenon appears
for sounds having a wave length about four times the
length of the tube. The sound is much strengthened.
A tuning-fork making say 435 vibrations per second
will have a wave length of about thirty-one inches. If
it be held while it is vibrating over a tube or vessel
of any sort, between seven and eight inches deep, the
increase in the strength of the sound will be very
marked. The motion in the air is so much swifter than
the prongs of the fork that, while one prong is beating
downwards and thus producing a condensation in the
air, the wave reaches the bottom of the tube; there
it is reflected, and gets to the top just as the prong
of the fork has returned to its normal position. As
the fork continues upward, forming a rarefaction, the
rarefaction also travels down the tube, and is reflected
so as to get back when the prong has returned to its
normal position; so for a complete vibration of the fork
the air wave has travelled four times the length of the
tube. It is possible in this way to make quite accurate
measurements of either the wave length of a sound,
SOUND 323
its velocity, or the number of vibrations a sounding
body makes per second. This phenomenon is called
resonance; and it is the chief factor in wind musical
instruments, such as flutes, organ-pipes, and the like.
Resonance in general means the ability of a body
to be thrown into sound vibrations by sound waves,
and there are two well-marked cases that need to be
considered. When the stem of a vibrating tuning-fork
is held upon a table the sound in the air is much
louder, for the whole table is made to vibrate at the
same rate as the fork. The table will resound loudly to
forks of any pitch. Such vibrations as are different in
pitch from that belonging to the body itself are called
forced vibrations. Resonance of this sort is the function
of the sounding-boards of pianos, the bodies of violins,
guitars, and other similar instruments.
If two tuning-forks have the same pitch, and one of
them be made to sound, the other one will presently
be made to sound also, though it be several feet away
from the former one. The air waves act upon it like a
pusher upon one swinging; at each return a little more
energy is added, until the amplitude has become great
enough to make the sound audible. Such vibrations
are called sympathetic, for they are only effective upon
bodies whose own rate of vibration is the same as
that of the sounding body. Raise the damper to the
MATTER, ETHER, AND MOTION 324
piano and sing a sound of any particular note, then
listen. The same note will be heard prolonged by the
piano. The particular string which can give that pitch
of sound has been thrown into similar vibrations, and
continues to sound as it would if caused to in any
other way.
The air as a body is too large to have a vibratory
rate of its own, and, consequently, all sounds in it
are properly called forced vibrations; but, when it
is confined in cavities, resonance becomes apparent,
and sympathetic vibrations may be so strong as to
be deafening. That is the case often in locomotive
furnace-flues when the door is opened. One may
hear it a mile or two. The resonance of large rooms
sometimes renders it very difficult to understand a
speaker in them.
The prolonged sound of thunder has been often
explained as due in some measure to echo from the
clouds, but it is doubtful whether clouds do echo
sounds. No one ever hears the sounds of bells, whistles,
or cannon, or other strong sounds, coming from the
clouds, as would be the case if they reflected sounds
appreciably.
When a single key of a piano is struck, there is
produced what is called a musical sound. There is a
definite pitch that is maintained. Strike half a dozen
SOUND 325
adjacent keys at once, and the effect is what is called
a noise, though each component by itself would give
a pleasing sound. A load of stones when tipped from
a cart makes a great racket; yet each stone, if struck
with a hammer, may give out a distinct musical sound.
Nearly every body has its own musical pitch; but, if
a number of bodies with different unrelated pitches
are listened to at once, the effect upon the ear is a
discordant one, and is called a noise.
When, however, two or more musical sounds whose
pitches stand in a simple ratio to each other are
heard together, they blend so as to form a pleasing
combinational sound. Thus, if one makes twice as
many vibrations per second as the other, the sound is
a very smooth musical one, and one is said to be the
octave of the other. If middle C of the piano makes
261 vibrations, the octave above will make 522, and the
octave below 130.5; and these may all be heard at once
as a musical sound. In music an octave is divided up
into eight parts called tones; and these are sung as do,
re, mi, and so on. If a string be stretched between two
points and the distance measured, the sound it will
produce may be called do of the scale. If the string be
now shortened by a bridge so as to produce the note
re, and the length of the string be again measured, its
length will be found to be eight-ninths of the length of
MATTER, ETHER, AND MOTION 326
the first, the note mi will be four-fifths, fa three-fourths,
sol two-thirds, la three-fifths, si eight-fifteenths, and
the next do one-half. As the number of vibrations a
stretched string will make is inversely as its length,
it follows that these fractions inverted will represent
the relative number of vibrations produced by each
member of the musical scale when compared with the
beginning or fundamental one. The following shows
the letters of the musical scale, with their ratios and
vibration numbers for the middle octave of the piano.
C D E F G A B C
9
8
5
4
4
3
3
2
5
3
15
8
2
1
261 293.62 326.25 348 391.5 435 489.37 522
The meaning of this is that 9
8  261 = 293.62, and
so on, so that the notes of the musical scale stand
in simple ratios to each other; and, if one has the
vibration rate of any one of them, he can compute any
others. Of course any octave above this one will have
simple multiples of these numbers for their vibration
numbers.
But these numbers signify more than simply this:
they signify that, when a second one is sounding with
C, it will make the number of vibrations represented
SOUND 327
by the numerator of the fraction; while C is making
the number indicated by the denominator. Thus, G
makes three vibrations while C makes two. The sounds
are concordant one-third of the time, and the effect is
a pleasing tone. On the other hand, D makes nine
while C makes eight, and the two are in accord but
one-eighth of the time; and the effect is displeasing,
and is called discordant. The smaller the ratio the
more musical and harmonious the sounds; and music
is made up of a succession of sounds standing in such
relations to each other, and, when different ratios are
employed, it is only for contrast, and return is quickly
made to these ratios. The ear will not long tolerate a
departure from them.
It has been stated that sympathetic vibrations would
cause a given body to vibrate. Press down gently a
base C on a piano, so as not to make it sound. Now
strike the C above it, holding down the key for a
second or two. On letting up the latter the sound of
the latter will continue to be heard, but coming from
the lower key, as can be learned by letting up the key,
when it will cease to be heard. If the G above the
struck C be now struck with the same low C held
down, the sound of the G will be heard from the base
string, and so one may go up, finding eight or ten
strings, each one of which will make the low C string
MATTER, ETHER, AND MOTION 328
vibrate, giving out the sound of the higher string. It
is found that each one of the strings able to do this
has a vibration number which is a simple multiple of
the lowest one. The first one is the octave, making
twice the number; the second one is the fifth of that
octave, making three times the number; and so on, to
the upper limit of the piano.
This means that a piano string is capable of vibrating
in a number of rates,—two, three, four, and so on, times
its own lowest rate, which is always called its pitch. It
is also found that this process is reversible; that is, if
each one of these keys in turn be held down and the
lowest one struck, they will each be set vibrating; and
this shows that the struck string vibrates itself in the
several different pitches represented by the multiples
of its fundamental rate. The sound of a piano string
is therefore a compound sound. In such a compound
sound the lowest one is called the fundamental, and
the others the over-tones, or harmonics. Some of these
harmonic sounds are likely to be stronger than others;
and some may even be so much more energetic than
the fundamental as to nearly drown the latter, so as
to make the pitch of the string to appear an octave or
more higher than it really is. The number and relative
strength of the harmonics in a compound sound make
the difference in the quality of sounds. In all such
SOUND 329
instruments as pianos, violins, guitars, and the like
string instruments, the number and strength of the
over-tones depend in a large measure upon how and
where the strings are struck and made to sound. A
piano string plucked near its middle point gives a
different sound from what it will give if plucked near
one end, and different in each case if plucked by the
fingernail and by the finger. So the quality of sound
can be much modified by mechanically varying these
factors.
In other musical instruments the sounds are also
compound in a similar way, differing in the number
and strength of the higher harmonics. Some have the
even harmonics, as the second, fourth, sixth, and so
on, stronger; some have the odd ones—first, third, fifth,
etc.—stronger; some have few, and some many. A flute
has but one or two, a violin has twenty; and thus
the character of the sounds of musical instruments is
explained.
As for the voice, the sound is produced by the
vibrations of what are called the vocal chords, which
are fixed at the junction of the trachea and æsophagus,
and through which all the air to and from the lungs has
to go. These chords are modified in tension by muscles
at will, and so change the pitch of the vibrations.
The cavities of the throat, the mouth, and nose act
MATTER, ETHER, AND MOTION 330
as resonators for these sounds and seem to strengthen
some of the constituents, thus giving prominence to
certain ones to the exclusion of others. That the mouth
acts this way may be observed by pursing the lips as if
to produce the various sounds of ah, oo, o, snapping
one cheek with the finger. These sounds will result;
while, with a little trial, one may thus snap a tune
which may be heard through a room, merely altering
the size of the mouth cavity. The cavity of the nose is
as important as that of the mouth. When this cavity
is small and narrow, there is produced what is called
a nasal sound. When this is prominent, and is not the
result of a cold, as is sometimes the case, the trouble
is a physiological one, due to the bad shape of the
resonating cavities rather than to careless habits, as is
often assumed by some teachers of expression. Some
different pitch of the voice in ordinary speaking might
be adopted, and thus in some measure prevent the
disagreeableness of the nasal sounds, but no amount
of painstaking can altogether prevent it. That structure
and its acoustic effects are an inheritance in some parts
of the world, as are crooked noses, thick lips, black
eyes, and broad heads in other and different parts of
the world, and is no more to be legislated away than
are these other physiological peculiarities. Neither is
it a proper subject of ridicule, more than lameness or
SOUND 331
defective vision.
If the bell of a locomotive be rung while it is swiftly
approaching one, the pitch of the sound rises until the
engine has reached the observer. As it retreats the pitch
lowers, and the difference in pitch becomes greater as
the velocity of the engine is greater. The explanation
of the phenomenon is, that one judges of the pitch
of a sound by the number of vibrations that reach
the ear per second. Suppose an observer be distant
eleven hundred feet from a source of sound of one
hundred vibrations per second. If both observer and
source remained in place, one hundred vibrations per
second would reach the ear of the observer, and there
would be one hundred more on the way to his ear. If
the observer should continue to go that whole distance
of eleven hundred feet to the source of the sound in
one second, he would not only receive all he would
by standing still, but in addition all that were on the
way to him,—two hundred vibrations in all,—or just
twice the number that would reach him if he remained
in place. Now, twice a given number of vibrations
represents a difference in pitch of an octave. The sound
he would hear would be an octave higher than the
sounding body was actually making. Any less velocity
than that supposed would make a corresponding less
difference in pitch, but such velocities as railway trains
MATTER, ETHER, AND MOTION 332
have may make a difference in the pitch of more than
a musical tone. Of course, if the sounding body and
listener be separating, a less number of vibrations will
reach his ear, and the pitch will be correspondingly
lowered. One may roughly determine the velocity of
a train of cars by noting the change in pitch of bell
or whistle. Thus, if the difference be, say a musical
semitone,—one-sixteenth,—then the speed of the train is
one-sixteenth the velocity of sound in air, one-sixteenth
of 1, 125 feet, which gives seventy feet per second, or
forty-seven miles an hour.
The ear is a complicated structure of tubes, muscles,
cartilages, bones, fibres, and nerves. The external part,
or conch, is of but little service in hearing in man,
for it cannot be directed, as can the ears of horses
and cattle. If it stands out from the head so as to
have some use as a collector, it is supposed to be in
abnormal position; but it is not much needed in any
case. The orifice of the ear is known as the tympanum,
a tube a little over an inch in depth and about a
quarter of an inch in diameter. At the inner end it
is covered with a thin membrane called the drum of
the ear. On the inner side of this membrane, there is
attached to the middle of it a bone fixed to a kind of
hinge, so that any movement of the drum of the ear,
in or out, makes this bone to move in a similar way.
SOUND 333
Then follows a network of bones and cartilages, and
a set of fibres known as Corti’s, of different lengths,
and whose function has been supposed to be for
sympathetic vibrations. There are in the neighborhood
Diag. 34.—The Ear.
of 4, 000 of these fibres, each one adapted to vibrate at
a different pitch. Then follow the nerve terminals and
the acoustic nerve itself, which goes to the base of the
brain, where its function as an acoustic instrument ends
with the delivery of its peculiar motions, interpreted
by consciousness as sound.
It is easily seen that the whole structure is one
adapted to receive vibratory motions from the air, within
MATTER, ETHER, AND MOTION 334
prescribed limits, and transmit them inwards where they
can be interpreted. The tube itself possesses resonating
properties like any other tube. The membrane is shaken
to and fro by sound vibrations, and this movement
is handed on to each distinct part until the nerve
itself is shaken. From beginning to end, it is only the
transfer of a particular kind of motion,—what is called
mechanical,—perhaps transforming it from longitudinal
to transverse vibrations. That it is so extremely sensitive
as to be affected appreciably by motions so slight as
the ten-millionth of an inch is a marvel, and shows that
mechanical motions of translation, though on a scale
of molecular magnitudes, is able, through the proper
avenue, to affect the mind and develop consciousness,
which experience enables the individual to interpret by
direct inference.
Let one reflect upon the facts furnished in great
abundance by physical science,—that all the data which
comes to the mind through consciousness, and which
furnishes what is called experience, is simply motion
of some sort. Touch, producing pressure upon the
surface of the body, finds a suitable nerve to transmit
to the base of the brain that kind of a disturbance;
sight, another kind of disturbance to the optic nerve,
transmitted to the same place; hearing, still another
kind of motion given to another kind of nerve running
SOUND 335
to the same headquarters. So, by means of motions of
various sorts man determines his place in the universe,
and learns how he may adjust himself to it.
MATTER, ETHER, AND MOTION 336
CHAPTER XI
Life
Any scheme of physics which fails to present that
great body of physical phenomena exhibited by living
things, both vegetable and animal, must be incomplete.
Many of these phenomena have seemed to be so
remote from ordinary mechanical operations that, in the
absence of definite knowledge concerning them, their
origin, factors, and relations to subsequent phenomena,
it is not to be wondered at that they were long thought
to be due to some peculiar force residing in a living
thing, which was not to be attributed to the general
endowments of matter, but only to be found in certain
organized forms of matter, which organization it had
itself built up as a habitat. It was conceived to exist
apart from any material organization as a kind of
entity. The difference between a living and a dead
animal was thought to be simply one of the presence
or absence of that entity called life. It was thought to
be able to effect changes in matter which the ordinary
physical and chemical forces could not possibly do;
and many of the chemical products of living things
LIFE 337
were supposed to be formed only through its agency;
and still more than that: it was held to be capable
of “suspending the action of chemical laws.” That the
stomach itself was not digested by the gastric juice
it secreted was held to be proof of its control over
chemical operations.
There have been many attempts to define life, but
the efforts have not been very successful. Thus Kant
defines it as “an internal principle of action;” Treviranus,
“the constant uniformity of phenomena under diversity
of external influences.” Bichat, “Life is the sum of
the functions by which death is resisted.” Duges
calls life “the special activity of organized beings.”
De Blainville’s and Compte’s definition runs thus: “Life
is the twofold internal movement of composition and
decomposition, at once general and continuous;” and
Spencer’s is “the continuous adjustment of internal
relations to external relations.” It will be observed that
in all of these what is described is a series of processes,
or a body of functions belonging to certain structures,
rather than an entity,—a description of what life does
rather than what it is.
Analogous difficulties were met in the attempts to
define other of the so-called physical forces. Thus
light was supposed to be a created something. The
corpuscular theory of it represented it as consisting
MATTER, ETHER, AND MOTION 338
of particles of some sort that ordinary matter could
absorb and eject, and which, therefore, had an existence
independent of matter. The establishment of its being
but wave motion in the ether completely destroyed the
notion of its having an objective, independent existence.
Heat, too, was supposed to be a kind of imponderable
matter, and certain phenomena in ordinary matter
depended upon its presence or absence; it, therefore,
was supposed to be an entity, and to have an
independent existence. Experiment showed it to be but
a particular kind of motion, so the idea that there was
any such thing as heat was abandoned.
Electricity and magnetism were supposed to be
fluids; and some of the early terminology still survives
in popular speech to-day, as when one reads that
the electric fluid struck a tree or entered a house.
Nevertheless, nobody now believes that either of them
is a fluid, or has an existence independent of matter.
The regular movements of the planets were thought
to require intelligent directive power to keep them in
their orbits; but now the gravitative property of matter
itself is held to be quite sufficient to account for all the
observed facts, and the extra material directive force is
held to be an entirely unnecessary assumption.
The discovery of the conservation of energy, covering
every field that has been investigated, led to the growing
LIFE 339
conviction that there are no special forces of any kind
needed to explain any phenomena. What seemed
probable forty years ago, to those who were conversant
with the facts,—that vital force as an entity has
no existence, and that all physiological phenomena
whatever can be accounted for without going beyond
the bounds of physical and chemical science,—has
to-day become the general conclusion of all students
of vital phenomena; and vital force as an entity has
no advocates in the present generation of biologists.1
The term has completely disappeared from the science,
and is only to be found in historical works; and every
phenomenon which was once supposed to be due to
it is now shown to be due to the physical properties
of a particularly complex chemical substance known as
protoplasm, which is the substance out of which all
living things, animals and plants, are formed. This
protoplasm is entirely structureless, homogeneous, and
as undifferentiated as to parts as is a solution of
starch, or the albumen of an egg. Minute portions
of this elementary life-stuff possess all the distinctive
fundamental properties that are to be seen in the
largest and most complicated living structures. It has
the power of assimilation,—that is, of organizing dead
1See Appendix, p. 477.
MATTER, ETHER, AND MOTION 340
food into matter like itself,—and, consequently, what
is called growth. It possesses the ability to move—that
is, of visible, mechanical motion, which is technically
called contractility; and it possesses sensitivity—that is,
ability to respond to external conditions.
It was formerly thought that the cell was the
physiological unit, a cell having walls differently
constituted from the substance enclosed, also a nucleus;
but as the microscope was improved, and anatomical
research continued, it became evident that the cell, with
its more or less complicated structure, was itself built
up by the structureless protoplasm. As before stated, it
is a highly complex substance, chemically considered,
made up of many atoms of carbon, hydrogen, oxygen,
and nitrogen, with a small number of atoms of sulphur
and phosphorus,—more than a thousand of them in
one molecule; and there appears to be a great number
of varieties of it. A small pellicle of this substance,
like a minute bit of jelly, without any parts or organs,
possesses its various attributes in equal degree in
every part. Any particular portion can lay hold upon
assimilable material, or digest it, or be used as a means
of locomotion; so that what are called tissues of animals
and plants are only the fundamental properties of the
protoplasm out of which they have been built—thrown
into prominence by a kind of division of labor. The
LIFE 341
protoplasm organizes itself into cells and tissues in the
same sense as atoms organize themselves into molecules,
and molecules into crystals of various sorts, having
different properties, that depend upon the kind of
atoms, their number and arrangement in the molecule.
The greater the number of atoms in a molecule the
less stability does it have, and especially is this the
case with molecules containing nitrogen. Many of its
compounds are so unstable as to be liable to explosive
disruption. This fact makes it easy to understand how
there exists, in a mass of such molecules no larger than
the minute ones seen in the microscope, conditions for
internal motions in the nature of explosions.
Let it be granted that atoms are in the neighborhood
of the fifty-millionth of an inch in diameter; then, if
a thousand of them are organized into a molecule,
its diameter would be about the five-millionth of an
inch. A speck of protoplasm, one ten-thousandth of
an inch in diameter, would require not less than five
hundred such molecules in a row to span it; and there
would be no less than one hundred and twenty-five
millions of such molecules in the small mass. Some
of these molecules would be less stable than others
on account of the internal motions that all the time
are present. Physical disturbances, external to such a
mass, such as temperature, ether waves of light, and
MATTER, ETHER, AND MOTION 342
chemical re-actions of any sort, and so on, can induce
and add to the disruption and other changes going on,
and visible motions might be expected to follow.
That such external agencies can bring about visible
motions of microscopic particles has long been known.
A few small bits of camphor dropped upon the surface
of clean water in a saucer will begin to move about
in a remarkable way. They will spin round, and travel
from place to place, and dodge each other in a manner
strongly like living things. A little gamboge, which is a
reddish-yellow gum used as a pigment, if rubbed up in
water and looked at through a microscope, will be seen
to have its particles in constant motion like animalcules.
This is known as the Brownian movement, and is caused
by temperature changes between the particles and the
water. Such phenomena are rather extreme cases of the
re-action of external molecular conditions upon a small
mass of matter, resulting in mechanical motions. In
protoplasm there is added to these same external ones
others of the nature of molecular explosions within
the mass, and together they give rise to a number of
effects, in which the transformed energy shows itself
in redistributing the molecules, absorbing additional
material, and movements of other sorts.
Biological researches within the past few years have
added vastly to our knowledge of protoplasm and its
LIFE 343
properties; and there is no longer any question that its
qualities are the expression of the various movements,
chemical and physical, and belong to it simply as a
chemical substance. Chemists have synthetically formed
out of the various elements a vast number of substances
that were not long ago believed to be formed only by
living things; and there is but little reason to doubt
that, when they shall be able to form the substance
protoplasm, it will possess all the properties it is now
known to have, including what is called its life; and
one ought not to be surprised at its announcement any
day.
Some of the phenomena exhibited by bodies called
inorganic, such as minerals of many kinds, possess
properties that are very like those supposed to belong
solely to living things. A spider or a lobster will have
a new leg or claw grow to replace one lost in any way.
In like manner a crystal will replace a corner or side or
any defacement so as to complete its symmetry before
it will begin to grow elsewhere, and this in cases where
the crystal has been defaced or incomplete for millions
of years, as is found to be the case sometimes in
geological specimens. Such phenomena have led some
of the most thoughtful and best informed naturalists
to query whether the evidence we have does not lend
much support to the theory that matter itself is alive, and
MATTER, ETHER, AND MOTION 344
The above picture is copied from a photograph. It represents the plume-like forms
assumed by water when crystallized in a basin. The similarity it presents to vegetable
forms is very striking. One may often see on frosty window-panes fantastic imitations
of organic things which forcibly suggest vitality. They are too common to be considered
coincidences.
LIFE 345
that the difference we observe in things is simply one
of degree rather than of kind. See opposite page.
In the brief space of this chapter, only an outline
of the relations between vital and physical phenomena
can be given, and of these, only a few of the more
prominent ones. It will suffice to show that such
phenomena as assimilation and growth, movement and
irritability, or sensitivity, have antecedents of physical
energy in the same sense as the movements of an
electric motor have physical antecedents in electric
currents, dynamos, steam-engine, and furnace.
The food of an animal consists almost altogether in
highly complex molecular compounds. It may be said
to be matter stored with energy. A pound of bread
may have the mechanical equivalent of twelve thousand
heat units, and if burnt in an engine would be better
for heating purposes than a pound of coal. When this
has been digested, and has done its work in the body,
the excreted products are of course equal in weight
to the original pound, for no kind of a physical or
chemical process affects the quantity of matter in any
degree; but the products themselves represent much
less complex compounds, and the energy has been
distributed through the body, carrying on its various
operations. There is, first, that of ordinary movement,
which can be measured in foot-pounds, as work of any
MATTER, ETHER, AND MOTION 346
kind may be. The blood in the arteries and veins has
to depend upon a kind of hydraulic apparatus to keep
it in motion. The temperature of the body demands
a supply of heat measurable in heat units to maintain
it, while the repair and waste going on through the
whole body of all animals implies a distribution of the
material necessary for the maintenance of the integrity
of the tissues, as well as a separation and removal of
the used-up material; that is, the material that has lost
all its available energy. The energy for doing all this
of course comes from the food, so the question is not
as to its source and quantity, but it is, How is this
transformation of energy in the body effected? Is it
direct, or is it indirect? This is the same as asking
as to the mechanism in the body, by means of which
energy supplied is transformed to meet the various
wants of the body.
Roughly, there are five different kinds of motion to
trace the antecedents of in the body of any of the
higher animals. First, there is the common mechanical
motions of the bony framework, which transport the
body from one place to another, or change the position
of a part with respect to the rest, as when one moves an
arm. Second, there is the motion of a muscle, wholly
different in character from the first, for the shape of the
muscle changes by contracting in length and increasing
LIFE 347
in diameter. The muscles are so attached to the bones
that the contractions of the one cause the others to
change their positions. The muscular contractions of
the heart, arteries, and veins keep the blood circulating;
and the same is true for the processes of digestion,
breathing, etc.
Third, there is the motion constituting the temperature
of the body, which, as has been explained, is altogether
atomic and molecular in its nature, and is, therefore,
in strong contrast with the other two.
Fourth, there is a kind of motion that is going on
throughout the body of the nature of transpiration, in
which solids, liquids, and gases are passing through
the various membranes without rupturing them. In
the lungs there is an exchange of gases, oxygen going
one way and carbonic acid gas going the other. In all
the mucous-membrane-lined cavities there is more or
less liquid oozing through the walls continuously, and
there is no tissue so dense but protoplasmic masses do
not move into or out of apparently with ease. They go
through the walls of veins and arteries as if the latter
were porous bodies, though no visible pores have ever
been discovered in them.
Fifth, there is the motion in the nerves, in the nature
of a longitudinal wave, and the velocity of which is
in the neighborhood of one hundred feet in a second,
MATTER, ETHER, AND MOTION 348
which, though it is slow compared with sound waves
or light waves, is fast when compared with the other
motions of the body. He is a swift runner who can
run at the rate of thirty feet a second for any distance.
The contraction of a muscle is to be measured in
fractions of an inch per second. The motion of heat,
measured as a rate of conduction, is exceedingly small
in the animal body,—probably not the hundredth of an
inch per second. The transpiration, or osmotic action,
is also a relatively slow movement, so that a velocity
of one hundred feet per second, which is upwards of
a mile a minute, is really rapid.
How and why the bone moves we know: it is
because the muscle that is attached to it contracts; but
how is energy spent to make a muscle contract? As
a matter of fact, when a muscle contracts it evolves a
considerable quantity of carbonic acid gas and water; it
also becomes acid, all of which imply chemical actions,
for these are chemical products. Carbonic acid gas and
water are the chief products of the combustion of such
material as foods, for they are made of what are called
hydro-carbons (combinations of carbon, hydrogen, and
oxygen chiefly); and when these elements re-combine,
forming water and carbonic acid, there is always a
relatively large but definite amount of energy given out
in the form of heat, and this effect is independent of
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time or place; that is, the same amount is developed
whether the process goes on fast or slow, or whether
it takes place in a furnace, in the body, or by slow
decomposition called rotting. When it goes on faster
than the heat can be conducted or radiated away,
the temperature rises and we say the body is hot.
When the heat generated is at once employed to do
work, as in a steam-engine, the temperature of it is
reduced proportional to the work done. When this
takes place in a contracting muscle better results follow,
for conduction and radiation within a muscle can take
place at only a slow rate; so the temperature rises,
and this explains the sensation of warmth resulting
from muscular exercise. The increase in perspiration is
also partly due to the same re-action of decomposition,
as water is one of the products. When the muscle
in contracting does additional work, as in raising a
weight, a corresponding amount of decomposition takes
place, and the heat is but transient, as it is at once
transformed into the muscular motion, which is as
much mechanical in its nature as is the movement in
a steam-engine.
The muscle is quite like a spiral spring, which may
contract upon itself and do work by contracting.
It is not the substance of the muscle itself that
undergoes the change of disintegration, evolving water,
MATTER, ETHER, AND MOTION 350
carbonic acid, and other products; but there is evidence
that the muscle secretes a particular substance called
inogen, the rapid decomposition of which causes the
contraction. As this substance can only be replaced at
a definite rate and in a definite amount, it is clear
that the work of a given muscle is limited by the
physiological processes that precede it. The rate of work
of a muscle is then determined by the rate at which
inogen can be secreted by the muscle, and work done
beyond that rate results in muscular exhaustion, which
in its early stages is called weariness, and requires
repose for fresh accumulation. Excessive draught upon
the muscles reduces their ability to secret inogen, and
their degeneration follows.
Muscular contraction is satisfactorily accounted for
without assuming any vital force. It has a purely physical
origin, the structure itself acting as a kind of mechanism
for transforming the chemical energy supplied in food
into the mechanical forms of energy represented by the
various movements of the body, external and internal,
which have already been mentioned.
That physical and chemical agencies bring about new
movements is of course well understood. Especially
clear is this for such nerve actions as accompany
the special sensations of sound, sight, touch, and the
rest. That the disturbance is properly described as
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a movement is apparent when it is found that it
has a rate of progression, as before stated, of from
one hundred to three feet per second. Whether such
movement be similar to a sound wave in a rod or
tube, or to an electric disturbance, makes no difference
so far as the transformation and transference of energy
are concerned. For sound there is the antecedent of
vibratory motions in the air; for light, waves in the
ether; for touch, mechanical pressure; for taste, chemical
solution; and for smell, gaseous substances with definite
constitutions and rates of vibration. These represent the
ordinary stimulants to action of such nerves, and so are
commonly understood to be the source of disturbance;
but every one of these so-called special nerves may be
excited to action by other agencies than the common
or normal ones, and the effect is the same. Thus, the
optic nerve may be stimulated by pressure, by cutting,
pricking, thumping, and electricity, and the effect is the
sensation of light; and, in the absence of other sources
of information as to the origin of the sensation, no
one could tell which of these was the originating one.
Every one of them, however, represents some form of
energy spent upon the nerve. What is important to
note about it is this,—the nerve transmits an impulse
it receives, quite indifferent as to its source, and is
interpreted as a definite sensation, quite independent
MATTER, ETHER, AND MOTION 352
of its origin. The latter is only an inference, and is,
therefore, liable to be erroneous.
But there are several other kinds of nerves, each with
some different function from the rest. Thus there are
nerves running to muscles, causing them to contract,
called motor, or efferent, nerves; secretory nerves, to
glands that cause secretions; vascular nerves, that cause
contraction or dilatation of the walls of blood-vessels;
inhibitory nerves, that affect other nerves so as to
moderate or entirely stop their action; reflex, or afferent,
nerves, which convey disturbances to the brain or other
nerve centres, but which cause no sensation; and still
others known to exist, but the special functions of
which are unknown.
To describe the action of any nerve is to describe
the transmission of energy in greater or less amount,
and transmission in all cases requires time. This does
not mean that the energy which does the special work
of moving muscles or the chemical transformations
of foods into tissues is transmitted by the nerves,
but that the transformations of energy already present
in each place where the work is to be done are
controlled by nervous energy in the same way as
a local galvanic circuit is controlled by a relay, or
the explosion in a mine is determined by an electric
spark. The energy available for all the purposes of
LIFE 353
an animal, including man, exists in the material of
the body. The activity of protoplasm in the various
cells transforms the various food stuffs into the proper
substances needed. The energy is already present; it is
only differently distributed by protoplasm; and nervous
action determines what changes, if any, shall go on at
a given place.
Temperature determines whether any of the physiological
process shall go on or not. Plants and animals
of a low order, such as snakes, frogs, and fishes, may
be frozen without injury. Some of the minuter forms
of life can withstand arctic winters, for there is an
abundance of insect life in those regions. On the other
hand, a temperature of 140 is destructive to the life
of everything except the seeds and spores of a few
microscopic beings. Some of these have been known to
survive a temperature of 200, continued for an hour or
more; but nothing has been found that can withstand
the boiling temperature of 212. The retarding influence
of cold upon vital processes can be understood by
considering that special chemical compounds require
special temperatures to form; and, if energy has to
be supplied to maintain the proper temperature, so
much the less will be at disposal for other processes.
If life processes were other than physical, it might
be expected that they would not be quite so rigidly
MATTER, ETHER, AND MOTION 354
conditioned by physical surroundings.
There is a distinction between a living plant or
animal and the seed or spore or egg out of which
they grow. Both are commonly spoken of as living
things, but the processes that constitute life in the one
are not present in the other in any degree; thus, for
example, growing corn and the grain of corn from
which the plant started. The grain of corn may be kept
in a suitable dry place for several years without any
apparent change, unless it be some loss in weight due
to evaporation from it. How long it may exist thus and
still be able to grow if planted is not known. Grains
of wheat found with Egyptian mummies buried three
thousand years ago have been said to grow, but there
is much doubt about it, and botanists do not credit the
story. A few years’ keeping in moister climates destroys
their ability to grow, and farmers always choose seed
corn from last year’s growth, which is an indication
that there is a process of slow deterioration going
on that ends after no long time in utter inability to
grow under any conditions. This ability to remain for
several years in a nearly stable condition is a property
of the seed that does not belong to the plant; for,
when growth has once really begun, it must keep on
growing or die: arrest is impossible, which seems to
show that life is a process rather than a condition, and
LIFE 355
the grain of corn is simply a combination of materials
where, under suitable conditions, life may begin.
The constitution of corn is well known; that is,
the elements out of which it is built up, and the
proportionate parts of each. Like other kinds of food,
it has carbon, hydrogen, oxygen, nitrogen, for the
chief constituents, and in addition a little sulphur,
phosphorus, iron, potassium, and a trace of some
others. These, when organized as they are in a grain
of corn, form a very complex body indeed. There are
not only molecular groups of many sorts, but these
are segregated into families, so that bodies of one
constitution are all in one locality, and bodies of other
constitutions in other separate localities, but definitely
arranged so as to be available when the life process
begins. Once formed, it appears to be as inert as
a crystal of any sort, and no change happens to it
until such physical conditions as heat and moisture are
provided. These it absorbs and transforms; a sprout
appears, then a root, each with different functions,
one for absorbing ether waves, the other for absorbing
water. The energy of ether waves is utilized in digesting
carbonic acid and building up the structure, and the
growth is simply the addition of materials gathered in
this way and elaborated into similar protoplasmic form
and structure. Growth implies transformation of one
MATTER, ETHER, AND MOTION 356
substance into the material of another, and is effected
by means of energy from external sources. The energy
of a stalk of corn may be found by using it as fuel
and finding its heat units per pound. It has about the
same value as wood. The corn itself has somewhat
higher value, which shows it to have a more complex
molecular structure, and is correspondingly less stable.
In like manner an egg, say that of a hen, possesses
a degree of stability that does not belong to it after it
has begun to grow. It may be kept with some care for
a few months and retain its ability to develop into a
chick; yet it ultimately wholly loses its possibility, which
shows that slow changes of the nature of disintegration
are going on that cannot be arrested. The physical
condition necessary to initiate the growth of the egg
is simply one of temperature. One hundred and four
degrees continued for three weeks completes the process.
When one reflects upon the nature of heat,—that it is
but vibratory motion,—he can at once see that energy
has been supplied to a complex mass of matter and
it has been chemically transformed. There are new
chemical products and new properties produced; and
however wonderful the completed product may be, the
factors at work to produce it have been absolutely
physical from beginning to end. After growth has
once begun the process must continue, at the peril of
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quick degeneration on stopping; so that an egg, like
the grain of corn, seems to be a material structure
where life may begin, rather than a living thing itself.
Such a distinction has not, however, been made in the
literature of the development of living things. It has,
perhaps, only a philosophical importance; but, if there
are any who would still hold that life is a something
sui generis, that may be considered apart from some
material structure and not as a transformation process,
it will be well for such to inquire what can become of
such life as a grain of corn or an egg has when either
of them is cooked, or when either of them is left for
months or years and they rot. At first it is in the grain
of corn or egg. If it be an entity of any sort it must
be somewhere else after leaving either the one or the
other. On the other supposition the question does not
arise at all, for it is plain that disintegration destroys
the molecular arrangement, and with the destruction
of that the properties of such organizations of matter
must go also; for the properties of a mass of matter are,
by general agreement, the result of the arrangements
of the matter. Woody fibre and starch are of precisely
the same chemical composition, but the properties of
the two are far from being identical.
What, then, is the distinction between what is called
living and dead matter? One is able to transform
MATTER, ETHER, AND MOTION 358
energy for its maintenance, and the other seems to be
wholly inert; yet, if analyzed, both may be reduced to
precisely the same amount of elements.
An analogy may make the distinction plainer. A
maker of physical instruments may make what is called
a Toepler-Holtz electrical machine. It is composed of
wood and glass and brass and tinsel and tin foil, and
possibly of other materials. Each one of these is got at
a different place from the rest, and all are assembled
in the shop of the maker. The individual parts are
shaped in particular ways, and these are at last fixed
in their appropriate places. The machine is done; but
it has never generated an electric spark, and one could
discover no electricity about it. Indeed, there is none,
any more than when the material was unshapen and
lying upon his bench. If the proper kind of energy is
spent upon it, however, it at once becomes electrified,
and electrical energy may now be got from it in
indefinite quantity, dependent wholly upon the proper
turning of the crank. If that be turned the wrong way,
or if it be stopped, the electricity soon quite disappears.
Now, it is the function of such a machine to transform
mechanical energy into electrical, and it does this so
long as energy is furnished for transformation and the
integrity of the machine is maintained. If one weighs
the machine before it has been worked, and also while
LIFE 359
it is electrified, he will find no difference. If the brass
buttons get off or displaced, if the belt gets broken
or the glass cracked, the machine will weigh just as
much as it did when they were in place; but the
property of the machine to transform energy will be
destroyed, and it may be as useless for the purpose
as a coffee-mill would be. One might speak of the
whole machine as an organism,—its wood and glass
and brass as its molecular composition, its function
depending upon each of these being in its appropriate
place, and nothing more. It can only exercise that
function when energy of the proper sort is turned into
it. If its molecular composition is deranged in any of
a dozen different ways, no one is surprised that it no
longer responds to the turning of the crank. If the
complete and perfect machine be called living, then
the one with its parts disarranged so it can no longer
perform its functions might be called a dead machine.
The egg may be likened to the machine. So
long as its molecular arrangement is intact, so long
it is competent to transform the heat supplied to
it and exhibit new properties. When the molecular
arrangement is interfered with, whether from within
or without, its function as transformer ceases, and we
call it dead.
It may be said, and often has been, that every
MATTER, ETHER, AND MOTION 360
living thing has an ancestry of living things; and in
human experience it is true. It is sometimes said that
one cannot get out of a mass of matter what is not in
it, which, in this case, might imply that matter itself
is alive, as suggested a few pages back, though I have
never heard any one so conclude. If one would apply
this dictum, let him settle with himself before turning
a new electrical machine whether the electricity he is
to get from it is or is not in the machine, and how,
if it be in the machine, he can get an infinite amount
from it by simply turning the crank. He may reach
the conclusion that what can be got out of a mass of
matter depends upon its composition and structure.
In conclusion, one perhaps can do no better than
to quote the words of Dr. Michael Foster, Professor
of Physiology, University of Cambridge, England, as
to the properties of protoplasm. “The more these
molecular problems of physiology are studied, the
stronger becomes the conviction that the consideration
of what we call structure and composition must, in
harmony with the modern teachings of physics, be
approached under the dominant conception of modes
of motion. The physicists have been led to consider the
qualities of things as expressions of internal movements;
even more imperative does it seem to us that the
biologist should regard the qualities of protoplasm
LIFE 361
(including structure and composition) as in like manner
the expressions of internal movements. He may speak
of protoplasm as a complex substance, but he must
strive to realize that what he means by that is a
complex whirl, an intricate dance, of which what he
calls chemical composition, histological structure, and
gross configuration are, so to speak, the figures; to him
the renewal of protoplasm is but the continuance of the
dance, its functions and actions the transferences of the
figures. . . . It seems to us necessary, for a satisfactory
study of the problems, to keep clearly before the mind
the conception that the phenomena in question are the
result, not of properties of kinds of matter, but of
kinds of motion.”
If such be the case, it is clear that the solution
of every ultimate question in biology is to be found
only in physics, for it is the province of physics to
discover the antecedents as well as the consequents of
all modes of motion.
MATTER, ETHER, AND MOTION 362
CHAPTER XII
Physical Fields
I.—THE THERMAL FIELD
When a mass of matter of any kind possesses
energy of such a kind as to be able to impart some or
all of it to the medium about it, whether that medium
be the air or the ether, which transmits or distributes
it outwards with a velocity which depends solely upon
the ability of the medium to transmit energy, and not
upon the source of it, the energy so distributed is
called radiant energy.
The term was first applied to the energy radiated
by a hot or luminous body, from which the heat was
said to be radiated away, the motions of the molecules
of the hot body being transformed into wave motions
in the ether. The wave motion thus set up is known
to be competent to set other masses of matter upon
which it falls into vibratory molecular motions, similar
to those that originated the waves. In other words, they
are capable of heating other matter. The space within
which such effects can be produced will evidently be
PHYSICAL FIELDS 363
limited only by the distance to which the wave motion
is transmitted, and this in turn depends upon the
special medium concerned—in this case the ether—and
the uniformity of its distribution. As has been already
pointed out, the ether transmits such wave motions in
straight lines, and to an indefinite distance,—so great at
least as to require not less than five thousand years to
cross the space accessible to our observations. As such
waves of all wave lengths travel with equal velocities,
and as all known bodies of matter are continually
radiating waves of many wave lengths, it follows that
in reality every molecule of matter sets the whole
visible and invisible physical universe in a tremor. The
magnitude of this effect is not now under consideration.
The space external to a body within which the body
can act in this physical way upon other bodies, so as
to bring them into a condition similar to its own, is
called its field. The heat or thermal field of a mass
of matter of any size and of any temperature must,
therefore, be as extensive as the universe, unless the
ether absorbs the energy to some extent and becomes
itself heated. At present there is no evidence that such
an effect is produced. Some astronomers have inferred
that absorption takes place, else the whole surface of
the sky would be bright with the multitude of stars
that occupy it. On the other hand, if absorption did
MATTER, ETHER, AND MOTION 364
take place in a manner at all comparable with gaseous
absorption, it would be selective in some degree, and
the more distant stars would have a color different
from those closer to us; and the colors of all stars
would depend upon their distance from us. If such a
condition had been observed, it would be conclusive
evidence of absorption in the ether, but it has not been
observed.
Furthermore, the perception of light implies a definite
though a small amount of energy; and, as the energy
of ether waves from a given point upon a surface varies
inversely as the square of the distance from the point,
it follows that there must be some distance from it
where the energy upon the retina must be too slight to
affect it; and hence the inability of the eye to perceive
the light could not be used as an argument against
the existence of the waves altogether. At the rate of
186, 000 miles per second light travels 5, 800000, 000000
(nearly six millions of millions of miles) a year, and in
five thousand years, which is the distance of some of
the more remote stars, 29000, 000000, 000000 (twenty-nine
thousand millions of millions) of miles. This, therefore,
is the known length of the radius of the thermal
or light field of a heated or luminous body; and,
as such heat-producing waves are radiated in every
direction about the body, the sphere having such a
PHYSICAL FIELDS 365
radius represents the space within which any or every
atom of matter can affect other atoms to heat them.
II.—THE ELECTRICAL FIELD.
The phenomenon called electrical induction, by
which one body becomes electrified by simply being
in proximity to another body which is electrified, is
another illustration of both a field and its property,
depending altogether upon its origin. But an electric
field differs in a marked way from a thermal field.
Imagine a sphere—say a cannon-ball—to be electrified,
and be isolated a long way from any other body. Its
effect upon the ether about it would be equal in every
direction. Practically, it would be distributed as the
thermal field would be; and, if the strength of the
field should be measured in any way, it would be
found to vary inversely as the square of the distance
from the body that produced the field. When such
an electrified body is adjacent to other bodies, as is
necessarily the case with every electrified body upon
the earth, the strength of the field at a given point
is found to depend upon the size, the nearness, and
the quality of the adjacent body. Suppose the adjacent
body were a similar cannon-ball, and its distance from
the former one foot. Then the strength of the field
MATTER, ETHER, AND MOTION 366
would be found to be greatest between them, and to
be very weak in the space equidistant and on the
opposite side. One may get a mechanical idea of the
condition of things by imagining straight lines drawn
from the electrified body when out in space as if they
were rays of light, evenly distributed in space. When,
as in the second case, another ball is near to it, these
rays crowd around the second one and apparently are
absorbed by it; and these may now be represented by
the same lines, starting at the same places as before,
but sweeping in curves to the second, with only here
and there one to escape into the unoccupied space.
The nearer the two are together the more closely are
these lines crowded together in the space between; and,
as the number of these lines in a given area represent
the strength of the electric field, it is plain the field
is strongest where the lines are most crowded. On
the other hand, if the second ball had been made of
glass, the field would have been changed but little,
for glass is a substance having but little absorptive
power for electric rays; that is, it is not much affected
by an electric field. When such an electrified ball
is suspended in an ordinary large room, these lines,
representing the field, are distributed about the room
in a manner that depends altogether upon the kind of
material there is in the room. The metallic objects, such
PHYSICAL FIELDS 367
as a stove, a steam-radiator, a gas-pipe, and the like,
will divide the field between them, not equally, for the
nearer ones will have the most, and other parts of the
space in the room will have but a trace of it. The
great distinction between the electrical and the thermal
field will be apparent when one reflects upon what the
latter would be for the same cannon-ball made hot and
suspended, in the same manner, in the room. The rays
go straight in every direction, and are not deflected
by proximity to other bodies. The one is uniform in
every direction about it; the other is warped by the
presence of other bodies.
An electric field, which is merely the ether in a
condition of stress, electrifies the bodies upon which
it acts; that is to say, it produces in them a condition
similar to that of the body that produced the field. It
does not heat them: it electrifies them. The process
is ordinarily called induction. If one would follow
mentally the mechanical conditions and changes that
take place when this process of induction takes place,
let him imagine the two cannon-balls suspended in
a room a few feet apart, and one of them to be
suddenly electrified artificially in any kind of a way,
as by connecting it to a charged electrical machine for
an instant. The re-action upon the ether will at once
begin. The stress into which it will be thrown will be
MATTER, ETHER, AND MOTION 368
propagated outwards as a wave, with the velocity of
light, and equally in every direction about it too, until
the advancing wave reaches the second ball, when the
absorption so reduces the stress that other parts of the
field can move towards it, thus distorting it; for at the
outset every part of the wave moved in a radial line.
This must be the case unless the field acted intelligently
instead of mechanically, and knew where it was to go
beforehand. Of course no one would suppose that, but
the remark is made to emphasize the necessity for the
mechanical steps in order to have clear ideas of what
has happened. The whole would happen in so small
a fraction of a second that it would be exceedingly
difficult to measure it, but the rate at which a thing is
done does not necessarily modify the way of doing it.
III.—-THE MAGNETIC FIELD.
The distribution of iron filings about a magnet gives
one a very definite mechanical conception of the shape
and properties of a magnetic field. It has before been
remarked that the shape of the field depended upon
the form of the magnet, and when this was altered
the field changed its form. That it too represents a
condition of the ether seems unquestionable. That it
is produced by the arrangement of the molecules of
PHYSICAL FIELDS 369
the magnet is also certain; but that presumes that the
atoms themselves are magnets, each having its own
field. When these atoms are either in disorder or so
arranged as to mutually cancel each other’s field, there
is no field observable. When they are made to all face
one way, their individual fields will conspire to produce
a resultant field, which will be strong in proportion to
the number of such individual fields that make it up.
The nature of this magnetic field is probably a kind
of whirl or spiral movement in the ether between the
two poles of the magnet; but, as two similar adjacent
whirls or lines are mutually repulsive, they spread out
into space indefinitely, and are almost always curved.
The earth as a great magnet has such a field, the lines
reaching from the north polar regions upwards and
southwards, re-entering the earth by similar downward
sweeps in the south polar regions. How far away from
the earth some of them may extend no one knows,
but there seems to be no reason why they should
not extend as far as any ray of light. There is good
reason for thinking that the other members of the solar
system are magnets, especially as iron and nickel are
so abundant in the sun and in the meteorites that reach
us from space. If that be the case, they are all moving
in each other’s magnetic fields. As the movement of
a conductor in a magnetic field produces an electric
MATTER, ETHER, AND MOTION 370
current in the conductor, and as what are known as
earth currents, apparently due to some extra terrestrial
source, are well known, their origin is accounted for.
But, when there is iron in a magnetic field, the latter
acts upon it so as to compel it to produce a field of
its own. In other words, it makes a magnet of the
iron. The process is called magnetic induction. Like
the other cases, it is a two-step process. There is, first,
the magnet with its molecular arrangement; second,
the action of the magnet upon the surrounding ether;
and, third, the re-action of the ether upon the second
body, making it a magnet. The heat field heats a
body, the electric field electrifies a body, the magnet
field magnetizes a body; and each of these fields may
exist separately or simultaneously, and each do its own
characteristic work, quite independent of either of the
others: so the same body may become magnetized,
electrified, and heated at the same time by the same
medium, acted upon by three different sources. The
magnetic field is more selective in its action than either
of the other two. A heat field will heat any kind of
matter in it if it be solid or liquid; an electric field will
electrify all bodies to some degree, but solid conducting
bodies to the highest degree; while the magnetic field
magnetizes only iron, nickel, and cobalt appreciably,
and the two latter but to a very small extent. The
PHYSICAL FIELDS 371
point of chief importance here is the function of the
field itself to produce, in a certain kind of elementary
solid matter, a molecular disposition and arrangement
similar to that of the body which produced the field.
IV.–THE CHEMICAL FIELD.
The phenomena attendant upon the combination
of atoms into molecules, and molecules in cohering
together to form larger masses, make it certain that
each atom has a peculiar field, which, for a name, may
be called its chemical field, within which it acts upon
the ether about it, and which extends to a distance from
it many times the diameter of any atom or molecule.
Chemists have concluded that there is really no
distinction between what has been called chemical
attraction and cohesive attraction; such, for instance,
as enables a drop of water to adhere to a surface, or
glue to hold wood surfaces together.
Crystals are built up of similar cohering molecules
arranged in a definite order. And these molecules exist
as independent bodies while in the solution before
being crystallized, and consequently each molecule must
have some degree of attraction for others; and this is
about the same as saying that there is an ether stress
about each one that depends upon its temperature, for
MATTER, ETHER, AND MOTION 372
crystallization cannot take place in a solution above a
definite temperature. But one of the best evidences of
a chemical field of the sort is found in the fact that
a solution of a given crystallizable salt has its process
easily initiated by putting in a small crystal of the same
kind of a substance. Moreover, the mere presence of
certain kinds of molecules among others is sufficient to
bring about chemical changes which otherwise would
not occur; while the catalytic body, as it is called, is
not changed. This is the case with starch, which is
converted into sugar by the mere presence of sulphuric
acid, which undergoes no change. This is apparently
inexplicable, unless it is admitted that molecules of
all sorts have fields which, in one degree or another,
control chemical combinations. This has been treated
of at some length in the chapter on chemism. Its
signification here is to point out again that the field of
similar molecules is of such a sort as to compel within
it an arrangement of atoms into similar molecules,
and molecules into similar positions, as exhibited by
crystals of any sort. It is, therefore, another example
of the property of a physical field to bring about in
a mass of matter within it the same kind of physical
phenomena as that which induced the field.
PHYSICAL FIELDS 373
V.–THE MECHANICAL FIELD.
A sounding body sets up air waves that travel
outwards radially from it in every direction to an
indefinite distance. Such periodic waves are capable of
making other bodies vibrate at the same rate as the
original body. When the second body has the same
specific rate, absorption takes place, the amplitude of
vibration increases, and the case is known as one
of sympathetic vibration. When the specific rate is
different from that of the recurring waves, there is
more or less interference, and this case is called forced
vibration. In all cases, however, the second body is
made to vibrate by the sound waves that fall upon it,
whether the medium be the air or any other substance,
solid or liquid. And the space within which such effects
are produced is the field of the first or sounding body.
If one considers simply the air as the medium of the
field, it will be perceived that sound waves travel in
every direction in it, and to distances unlimited except
by the presence of the air itself. Of course, the farther
the distribution goes on the less energy there will be
to any cubic inch or any other dimension, and there
must be some limit where the energy is too small to
affect the organs of hearing; but such a limit ought not
to be considered the actual limit of sound vibrations
MATTER, ETHER, AND MOTION 374
or the field of the sounding body. There is no reason
for doubting that every sound vibration of every kind
and degree is distributed throughout the whole earth
and its atmosphere, and more than that: as the impact
of molecules in sound vibrations results in heating
them to a higher temperature, increased radiation into
space follows, and the consequent energy in this form
must affect in some degree every particle of matter
in the universe upon which it falls. It is plain how
far-reaching almost every act and movement of every
kind must be.
A sound vibration, being a to-and-fro movement
of a mass of matter, may easily be great enough to
be seen, as in the case of a tuning-fork or a piano
string; and, therefore, it is treated as being mechanical
as distinguished from molecular: but even where the
sound vibration is too slight to be seen as an actual
displacement, it can give to another body a large
amount of visible motion, as when a suspended marble
is held against a sounding tuning-fork, or as when a
paper windmill is held over a sounding Chladni plate.
The motion of a sounding body being mechanical,
the field it produces may be called the mechanical
field, because the effect of it upon other bodies is
similar in kind to that which produced the field.
There are, therefore, five well-defined modes of physical
PHYSICAL FIELDS 375
action,—heat, electricity, magnetism, chemism, and
sound,—which, in the past, have often been called
physical forces, each one of which affects the medium
about it, producing either a stress or a motion,
or both—conditions that travel outwards into space
indefinitely, and constitute as many different physical
fields. They may all co-exist in the same space without
interference, and each one produces upon other bodies
of matter within it the same physical condition of
motion, position, or arrangement as that which initiated
the field itself. So the established relation deserves to
be called a law better than many relations that are
called laws, but are such only within rather narrow
limits (as, for instance, the law of Charles and Boyle’s
Law), inasmuch as this law of physical fields is as
universal as gravitation.
What is called gravitation might be included in this
list, for every particle of matter attracts every other
particle near or far; so every atom has a gravitative
field as extensive as the universe, and there is no
more interference between it and the other fields than
there is between any of them. The chief distinction
between the gravitation field and all of the others is
that they are all artificially variable while gravitation
is not known to be, though some phenomena indicate
the possibility of it.
MATTER, ETHER, AND MOTION 376
It follows, from the foregoing, that every object large
or small is continually affecting the space about it in
several different ways,—through its temperature, electric
and magnetic conditions, as well as by its various
movements; and it also follows that the shape of a
body as well as its molecular arrangement determines
whether the field shall be symmetrical or otherwise. A
crystal certainly has a symmetrical field, but it cannot
be turned over in the hand without affecting in some
degree everything outside of it.
If it be true for certain collocations of matter that
external form and molecular arrangement determine
the existence of its field, it is difficult to imagine why
it should not hold true for all cases,—a cell structure
for instance, in which case the organization of a similar
cell in adjoining space where the proper material
for construction exists would only be in accordance
with the physical properties of fields in general; and
the phenomenon of growth would be as definitely
understood as the growth of a crystal. This is not
demonstrative; but it is in accordance with everything
else we know, and is what would be predicted by one
who knew the properties of physical fields, though he
had no knowledge of cell growths.
To take one step more, yet not to go beyond the
domain of physics: It is as certain as any physical fact
PHYSICAL FIELDS 377
can be that every movement of an individual—change
of attitude, gesture, or expression of countenance—must
produce a corresponding change in his field, and tend
to bring about in others similar movements; and, even
if such phenomena are not observed in every one, it
is no more of an argument against the existence of
the operative conditions than is the failure to perceive
through the sense of feeling the sound vibrations
produced by a speaker’s voice, when it is certain the
whole body is in a state of tremor; and the effect
of sympathetic speech is more largely physical than
has been supposed. Strong emotions, or the physical
semblance of them by skilful actors, re-act in the same
physical way. This is not saying there may not be
other factors, but the purely physical ones are present
and act in the way described. The term “sympathetic
action” was applied to physical phenomena when it
was discovered to be a mode of action quite analogous
to mental phenomena between individuals in which
similar mental states are induced.
Lastly, so far as mental action depends upon brain
structure, any changes in the latter must produce
corresponding changes in the brain field, and there
must be a brain field if there be any truth in the
foregoing; the conclusion is inevitable. Other similar
structures must be affected in some degree by them,
MATTER, ETHER, AND MOTION 378
and whether such induced changes be able to induce
similar brain changes with the accompanying mental
phenomena or not must evidently depend upon the
possibility of synchronous action.
This is not to be understood as asserting that such
thought transference as is implied in the foregoing
actually occurs. All that is asserted is that the physical
conditions necessary for such transference actually exist,
and one who was acquainted with the properties of
physical fields would certainly predict the possibility
of thought transference in certain cases.
ON MACHINES.—MECHANISM 379
CHAPTER XIII
On Machines.—Mechanism
The common notion of a machine is that it is
an implement designed for doing this or that: as,
for instance, a loom is a machine for weaving cloth
or carpets; a steam-engine is a machine for driving
machinery; a water-wheel, for utilizing the power of
water; and so on. Some of these structures, built
for specific purposes, are highly complex, and many
of their parts stand in curious relation to each other,
and altogether they may be able to produce results
that seem but little short of intelligent action. Looms
weave out beautiful fabrics with artistic designs in
colors, when furnished with only the bare threads.
The hair-cloth loom draws with iron fingers a single
hair from a large bundle of hairs. If it fails to grasp
one, another and another attempt is made until one is
seized, and meanwhile the rest of the machinery waits.
If it seizes more than one, as sometimes happens, it
drops both and tries again, the rest of the apparatus
waiting as before, exhibiting a kind of deliberativeness
and consciousness of what it is about that one hardly
MATTER, ETHER, AND MOTION 380
looks for through any combination of wheels, ratchets,
levers, and the like, such as make up a complex
machine. Every one knows that by far the larger
number of things in common use which were formerly
made by hand tools are now made by machinery more
rapidly and oftentimes more perfect than they could
be made by hand. The parts of clocks and watches are
so made; papers are printed, folded, and directed at
the rate of ten thousand in an hour by one machine;
grass is mown, grain is cut, threshed, and winnowed
by one machine as fast as it can be driven through
the field; shoes, toys, and beautiful pictures are thus
made by the million, and there is no department of
human effort but is dependent upon mechanism of
some kind. In many cases the entire work is thus done
automatically, as when pins and needles are made from
the wire, sharpened, polished, counted, arranged in
papers, and folded ready for the market. There is no
field independent of such aids. Even music is absolutely
dependent upon it, and all that is called sentiment and
feeling in it are resolvable into degrees and directions
of movements for the production of sounds; and there
are no movements of muscles but may be duplicated
by automatic mechanism. If the effects produced by
mechanism to-day are not the effects wanted, it only
shows that the mechanism has not been perfected, not
ON MACHINES.—MECHANISM 381
that it cannot be done.
If one considers the almost infinite number of
processes needed for the maintenance, conveniences,
comforts, and tastes of what is called civilized life,
it might seem as if an almost unlimited number of
physical conditions would be necessary; but let such an
one recall the fact that all kinds of motions are reducible
to not more than three fundamental kinds,—translatory,
vibratory, and rotary,—and he will be prepared to trace
the most complicated movements to these elementary
forms.
In the chapter on motion, only the kinds of motion
were considered; but here it is proposed to point out
the conditions under which motion is transferred from
one place to another, and how these elementary forms
are transformed into each other. For convenience, the
term “mechanical motion” will be employed for all
having visible magnitude, but simply on the ground
of visibility, not because there is any other distinction
between such motions and those of a molecular or
atomic kind.
When one pushes against a paper-weight on the
table and it moves in consequence, no one is surprised,
for the movement is expected. If the weight were free
to move and it did not move, no matter how strong the
push, one would have reason to be surprised, because
MATTER, ETHER, AND MOTION 382
such a phenomenon is not in accordance with the
experience of mankind. If one billiard-ball in contact
with another one received a push in direction toward
the latter, the latter would be moved in the same
direction, and the motion of the second one would be
explained by saying it was due to the push of the first
upon it. Suppose there were ten or a hundred such
balls in a line. If the end one was pushed towards the
rest of them, they would all move, the farthest one as
much as the first, as the movement imparted by push
to the first would be handed on step by step to the
last. If the balls were glued together at their points of
contact, that would make no difference in this transfer
of motion by contact; and, if there were a thousand
or a million, or any other number, there would be no
difference. Neither would there be any difference if the
separate balls were no bigger than molecules. A rod of
wood or metal is entirely made up of a great number
of cohering particles, and, when a push is applied
to one end, every particle is pushed as much as the
end particles. If there was a row of thin rubber balls
and the end one was thus pushed, the side would be
flattened somewhat, and the opposite side in contact
with the next adjacent ball would push against its
neighbor and each be flattened, and so on, till the last
one was reached, which would be pressed on one side
ON MACHINES.—MECHANISM 383
but not on the other, and would, therefore, be like a
single ball pressed upon one side. The intermediate
balls would act as transferrers of pressure from one
end to the other. The rubber balls so flattened by
pressure will recover their form when the pressure is
removed, and the same may be said of a rod of any
material, the difference in this particular being only
one of degree. The same process takes place when one
pulls upon a rod. It is to be remembered, however,
that in either case the transmission of the pull is not
instantaneous for any distance, however short. Time is
requisite, and hence there is a rate of propagation of
such motion in all bodies, which depends upon the
degree of elasticity and the density of the material; and
this rate cannot be exceeded, no matter how great the
initial push or pull. This rate is about sixteen thousand
feet per second for steel and the most elastic woods,
and is about eleven hundred feet per second for air. If
one inquires what the condition is that initiates motion
in any given body, it will be found to be a push or a
pull, and either of them may be measured in pounds.
The chief distinction between a push and a pull lies
in the relative position of the moving power and the
body being moved by it. In the push, the body being
moved leads in the line of movement; in the pull, the
moving power leads. When a locomotive goes ahead
MATTER, ETHER, AND MOTION 384
of the train, it pulls; if the train goes ahead, it pushes.
A stiff rod or bar may be used for either a push or a
pull, but a rope can be used only for a pull, for when
pressure is applied to it longitudinally it bends at right
angles to the direction of the pressure, and so fails to
act in the right direction. A rod can transmit a push
or pull only in the direction of its length, while a rope
may rest on a pulley and the pull may act upon any
other body in the same plane the pulley turns in. If a
pressure of ten pounds be applied as a push at one
end of a rod or bar, the whole of that pressure may be
transmitted to the other end. The same may be said
of the pull either with a rod or rope, but neither rod
nor rope can possibly transmit and give up at the one
end more than is applied at the other. For this reason,
a rope hanging over a pulley will hold equal weights
on its two ends. If a ten-pound weight be tied to one
end, the pull transmitted will be ten pounds, which
may be balanced by a pull either by weight or in any
other way on the other leg of the rope. The function
of a pulley is to change the direction of the pull: it
does not alter its amount.
ON MACHINES.—MECHANISM 385
MECHANICAL MACHINES.
In the older treatises on natural philosophy, there
were described several machines which were called
the mechanical powers, because their principles were
embodied in mechanical devices for transmitting pressure
or pulls. The lever stood first among them. It consists
of a stiff rod or bar resting upon a point of support
for it called a fulcrum, and this fulcrum may be placed
anywhere between the ends of the bar. The advantage
or disadvantage of this machine depends upon how
near the fulcrum is to the body to be moved. A stiff
rod four feet long supported at its middle would be
balanced if it were of uniform dimensions. If a weight
of ten pounds was hung at one end, an equal weight
or pull would be needed at the other end to balance it.
If one weight fell one foot, it would do ten foot-pounds
of work in raising the other ten pounds one foot. In
any case the work done, measured in foot-pounds, will
be the same at both ends of the bar or lever.
The lever changes the direction of motion or the
amount of pressure, but does not change the amount
of work measured in foot-pounds.
The simple pulley is a device for changing the
direction of a pull, as seen in the apparatus for raising
merchandise to higher levels in buildings; but by far
MATTER, ETHER, AND MOTION 386
the most extensive use of it is in the transfer of a
continuous pull from one place to another through the
agency of belts of leather or other pliable material.
This combination of pulley and belt is adaptable to
many places and purposes, as well as permitting great
ranges in speeds of rotation by simply making the
diameters of the pulleys proportional to the differences
in rotation wanted. It is the chief agency in machineshops,
factories, etc., for distributing the power to the
various machines. By crossing the belt the second
pulley can be made to turn in the opposite direction.
In all the ways in which it is serviceable, it is plain
that it cannot deliver more of a push or a pull than is
given to it any more than can a lever. There is no gain
of energy or work by its use, but always some loss,
because friction uses up some of the working-power in
other than useful ways. The wedge, the inclined plane,
and the screw are but simple devices for utilizing push
or pull; but there are other means also employed for
the same purpose; for instance, the pressure of the air
or other gas, and steam. Windmills are made to turn
by the pressure of the wind upon the inclined blades,
and, by forcing air into pipes, an increased pressure
may be transmitted for long distances and then used.
The reason this method of using air is not in more
general use is that when the air is compressed it heats.
ON MACHINES.—MECHANISM 387
The heat it loses soon if conveyed in pipes very far, and
as a consequence its pressure is very much reduced,
so it is not an economical thing to do. Water-wheels
utilize the pressure of water, and the amount of work
it can do is definite and easily calculated. If at a
waterfall a hundred pounds of water falls ten feet, then
it can do 100 10 = 1, 000 foot-pounds of work; that is,
it can raise 1, 000 pounds a foot high, and so on for
any other amount. A perfect water-wheel that did not
let slip by any water without its doing its work would
give up practically 1, 000 foot-pounds. Really, the best
water-wheels give but about ninety per cent of the
working-power of the water. So-called water-motors are
but properly constructed wheels enclosed in the pipe
through which water is made to flow with considerable
pressure. In the cases of air, steam, and water power
there is the condition we call a push, which may be
measured in pounds; and a push measured in pounds
multiplied by the distance in feet through which it is
maintained is the measure of work.
In each of the cases, the air, or steam, or water, as
it moves on and does its work, gives up the motion it
has; and the substance itself, being no longer of use,
is allowed to escape as a waste product. Such bodies
have been sometimes called prime-movers.
So far has been considered only the apparatus in
MATTER, ETHER, AND MOTION 388
common use for transferring motion of one body to
other bodies, but frequently it is important to have
the form of the motion changed from the kind it may
chance to have at the outset to one better adapted to
the special end desired.
In a sewing-machine, for instance, the particular
movement of the needle must be vibratory. The treadle
has a similar movement, but not rapid enough; so there
is arranged between them a series of movable parts,
which not only transfers a certain amount of motion,
but the latter is transformed into appropriate forms. The
vibratory motion of the treadle is transformed into the
rotary motion of the balance-wheel, this into swifter
rotation of the pulley by means of a belt; then by lever
and cam the needle receives its proper kind of motion,
the shuttle a similar one at right angles to that of
the needle, and the other moving parts such forms of
motion, and rates of motion, as are needful for their
special kinds of work. In a steam-engine the constant
pressure of the steam is made to act upon the alternate
sides of a piston, giving it a vibratory motion, which
must be transformed for most purposes into rotary;
and this is effected by means of a crank, which is,
therefore, a device for transforming vibratory motion
into rotary, or vice versa. When the driving-wheels of a
locomotive are made to rotate, their adherence to the
ON MACHINES.—MECHANISM 389
track carries the whole structure forward; that is, the
rotary motion is transformed into translatory. In the
stationary engine the rotary motion of the balance-wheel
is transferred to a pulley by a belt, and the shafting
transfers this through its whole length to other pulleys.
If the reader will follow back to its antecedents any
particular motion he may think of, he will see that
the function of each movable part of a machine of
any sort is to transfer push or pull, or transform one
kind of motion into another kind. However complex a
machine may be, it does no more.
It is to be noted that what a given thing will or
may do depends altogether upon what kind or form of
motion it has, not upon how much motion or energy it
has. For instance, a bullet might spin on some axis on
the table before one, and have great rotary velocity and
energy, yet be perfectly harmless; whereas, if it had the
same amount of energy with the motion translatory, it
might be destructive to anything it struck.
MOLECULAR MACHINES.
If one of the functions of a machine be to transform
the kind of motion it is supplied with into some other
kind of motion,—translatory into rotary or vibratory,
any one into either of the others,—one may be prepared
MATTER, ETHER, AND MOTION 390
to follow mechanical processes from masses of visible
magnitude into molecular magnitudes, and thus note
the antecedents of the new phenomena that appear.
When a gas is condensed by pressure the individual
molecules have less free space to move in, and they
consequently collide with each other more frequently.
Being elastic, their average amplitude of vibration is
increased proportionally, and a greater number of them
will strike with greater velocity upon the walls of the
containing vessel per second than before. Thus the
temperature and the pressure of the gas are increased.
We say that mechanical energy has been converted into
heat energy, or sometimes simply into heat, though
what has really happened has been the transformation
of external translational motion into internal vibratory
motion, which the elasticity and mobility of the
molecules permit. When by friction or percussion a
body is heated, the same thing precisely has happened:
translatory motion has been transformed into vibratory,
through the agency of the molecules, which have,
therefore, acted as machines for transformation.
In like manner the reverse transformation may take
place in several ways. When the increased vibratory
motion of the molecules produces an increased pressure
upon the movable head of a piston in an engine, the
piston as a whole may move and do work. Also, when
ON MACHINES.—MECHANISM 391
the molecules strike harder upon one side of a surface
than upon the other side, the surface moves toward the
side of less pressure, as with the radiometer; so that both
engine and radiometer are machines for transforming
vibratory molecular motions into translatory mechanical
motion.
When the temperature of steam is raised to about
5, 000 F., the amplitude of vibration is so great that
the atoms can no longer cohere in the molecules, and
they become separated into the gases hydrogen and
oxygen; and again vibratory motion is transformed into
translatory, which in gases is called free-path.
Heat is also largely derived from the chemical
properties of coal, wood, oils, gas, and other substances
called fuel. As the heat is derived from some antecedent
condition which is not heat, it follows that the stove
or furnace is a machine for transforming into heat
motions those motions which constitute and are the
measure of chemism.
When heat is applied in any way to the face of
a thermo-pile, electricity may appear which may be
made to do work in many ways. The vibratory motion
disappears as such,—that is, it is annihilated,—while an
electric current appears as its substitute. The thermo-pile
is, therefore, a machine for the transformation of heat
into electric current. If heat be a kind of molecular
MATTER, ETHER, AND MOTION 392
motion, then an electric current must be some other
kind of motion!
When the armature of a dynamo is turned and
an electrical current is developed, the latter is the
representative of the mechanical movement of the
armature. It takes more power to make it move at a
given speed when it is producing a current than when
it is not. The current represents the difference. It is
mechanical motion that goes into the dynamo, and an
electrical current comes out of it; and hence a dynamo
is a machine for the transformation of mechanical into
electrical motion. One is visible, the other molecular,
as is the case when friction develops heat.
An ordinary static electrical machine possesses a
similar function.
On the other hand, a galvanic battery transforms
chemical into electrical motions; and, in every case
where electricity is developed, there is some sort
of apparatus which receives one kind of motion for
transformation. That one kind of machine will transform
mechanical motion, a second heat, a third chemical,
all into the same kind of a product, helps one to
see that the antecedents, which at first seem to be so
unlike, are really but varieties of the same condition,
namely, motion, which, when transformed by suitable
machines, might be expected to appear as a similar
ON MACHINES.—MECHANISM 393
product of each.
An electrical current always heats the conductor
through which it passes. It is, therefore, an antecedent
for the production of heat in the same sense as
mechanical motion is an antecedent in condensation,
percussion, and friction; and the conductor is the agency
for the transformation into the vibratory molecular form.
So far as the production of light by electricity is
concerned, whether by the incandescent or the arc
system, the function of the current is to raise the
temperature of the conductor to the proper degree for
luminousness. The light comes from the hot molecules,
not from the electricity; but here, as in the simpler case
of heating the conductor, the conductor itself, whether
it be a filament of carbon or the tips of the carbon rods,
acts as a transformer of electrical into heat motions,
and thence to ether waves.
Ether waves may be transformed in two different
ways. First, by falling on molecules of matter; the latter
absorb them, and are heated in consequence, which
is the converse of the production of ether waves by
heated molecules. Second, by their own interferences
plane, elliptical, and spiral waves may be produced,
which resultant waves are capable of affecting matter
in different ways. One of these consequences is of so
much theoretic importance it will be well to allude to
MATTER, ETHER, AND MOTION 394
it.
Given a flexible section of a spiral ether wave, no
matter what its origin. If its ends were to come
together, there is good reason for thinking they would
close and weld together, forming a ring, which would
then be practically a vortex ring. The ends of vortex
rings formed in the air will do thus, so if the atoms of
matter are really vortex rings, as has been supposed,
the above suggests how they may originate, or how
matter is created.
All the different kinds of phenomena which are
generally attributed to different forces one may readily
trace to these antecedents; namely, matter, ether, and
motion of various forms. The condition necessary
for a new phenomenon to appear is that the present
forms of motion in either matter or ether needs to
be transformed. Atoms and molecules, as well as
large masses of them, which we call bodies of visible
magnitude, act as machines for the transferrence and
the transformation of motion; and one might define
a machine as a collocation of matter having for its function
the transferrence or the transformation of motion, or both. An
atom and a molecule, then, are as much machines as a
steam-engine or a dynamo; and every molecule in the
universe, whether near or remote, is constantly receiving
and transforming energy through its individual motions.
ON MACHINES.—MECHANISM 395
What the particular phenomenon will be in a given
case depends upon the form of the motion received
by the mechanism and the new form which the latter
has made it to assume. As before remarked, what a
given mass of matter will do depends upon the kind
of motion it has.
So far nothing has been said about the relation of
these mechanical principles to living things,—animals
and plants; but it will be obvious to every thinking person
that unless, when matter assumes the forms exhibited
by such living things, it surrenders its mechanical
properties and relations, then such transformations
must be going on constantly in all living things.
Mechanical motions, chemical re-actions, heat, and so
on, ought to be expected from such complex machines
as animals. Foods, as fuel, air, and water, are physical
factors which imply metamorphosis; and the forms into
which the factors will be changed depend upon the
special mechanism provided. Hence, an animal is a
complex machine for the transformation of motions of
various sorts, the sum of them being what are called
the phenomena of life.
The foregoing analysis shows that what have
heretofore been considered as forces in nature are
non-existent; that all phenomena in the different fields
of physics are simply and plainly mechanical; and that
MATTER, ETHER, AND MOTION 396
an application of the laws of motion, as presented
by Sir Isaac Newton, supplemented by the laws of
ether action, is sufficient to account for all kinds of
phenomena: and therefore the supposition of particular
forces of any kind is entirely unnecessary. What have
been called forces are but various forms of motion,
of matter, or of the ether, each embodying energy;
the particular phenomenon a given body may produce
depending upon its size and the particular quality of
motions it chances to have. Granting this, one may
at once perceive that expressions implying higher and
lower forms of force are misleading. No one is higher
in dignity or importance than any other one. Let
one ask the question, Which is higher, vibratory or
translatory motion? and he will see the absurdity of
the language.
If one will bear these principles in mind, they will
be helpful in unravelling phenomena which otherwise
may appear to be very puzzling. For instance, one may
frequently come across the statement that one cannot
get out of a machine what is not in it or put into it. Is
it so? Coal is put into the furnace, and heat comes out.
Mechanical motion is put into a dynamo, and electricity
comes out. A current of electricity is turned into an
arc lamp, and light comes out. The character of the
product thus depends upon the form of the machine
ON MACHINES.—MECHANISM 397
and its relation to some antecedent factor. The physical
knowledge we have enables us in most cases to trace
and understand the metamorphosis. In some cases the
molecular changes are not so completely known in
detail, yet the quantitative relations between what goes
in and what comes out of the machine are so definite
that one is warranted in asserting that no other factors
are present than the one considered. In one sense the
product of any machine is like its antecedent, if both be
but kinds of motion, or forms of energy as some prefer
to say; but if one assumes that these various forms of
energy differ in any way from forms of motion, or that
they have distinct individualities, then one can get out
of a machine what he does not put into it. What seem
to be more unlike than the mechanical movements of a
steam-engine and the electricity of the dynamo? One is
simplicity itself; the nature of the other, its product, has
been the despair of philosophers for generations. The
subject is of fundamental importance chiefly because
some philosophers have evolved their schemes without
duly considering these obvious relations.
However much a given phenomenon may differ in
character from its known antecedents, no good reason
can be assigned for thinking that, when properly
analyzed, it would be found resolvable into other
factors than matter, ether, and motion. Furthermore,
MATTER, ETHER, AND MOTION 398
there is no evidence that any one of the physical forms
of motion is or was necessarily prior to any other. As
there is no hierarchy among them, no one of them
can be called primal. A linear arrangement does not
properly represent their mutual relations. They are
more like a closed ring of interrelations thus:—
Diag. 35.—Forms of Energy.
The visible universe may be considered as a vast
machine, within which motions are being exchanged by
contact and by radiation. It is not the absolute amount
of energy a body may have which determines whether
it shall give or receive, but it is the degree it has of
a given kind of energy. Thus it is the temperature of
a body that determines for it whether it shall gain or
lose heat in the presence of other bodies. The whole
tendency is towards equalization of conditions, and
ON MACHINES.—MECHANISM 399
for this reason some philosophers think they foresee
the end of this act in the drama of the solar system.
The possibility of the variety of phenomena that gives
interest to existence depends upon the fact that at
present matter is in an unstable condition, and, when
uniformity of condition is reached, there will be an
end to changing phenomena. Astronomers have figured
out that in five or ten millions of years the sun will
have radiated away so much of his energy that the
earth will no longer be habitable. Perhaps so; but it
is certain that the whole solar system is drifting in
space somewhere at the rate of seven hundred millions
of miles a year, and in one million of years it may
reach a region in space where the present rate of loss
might be greatly reduced. In that time it will have
travelled three times the distance to the nearest of the
fixed stars. It could hardly be where its expenditure
would be greater than now. If it should drift into one
of the great hydrogen regions such as are numerous
in the heavens, not only would the supply of energy
be renewed indefinitely, but the earth would become
uninhabitable in an hour. At any rate, there is no
guarantee in nature for permanent stability, supposing
that stability should be attained; for simple mechanical
impact between the sun and any of the millions of
stars would not only annihilate the earth as such, but
MATTER, ETHER, AND MOTION 400
would so reduce to a nebulous mass the matter that
now composes the solar system that the whole process
of world formation would have to be gone through
with again. The sudden blazing out of stars here
and there in the heavens shows that similar physical
processes are taking place elsewhere in the universe.
Such an end is quite as probable as the refrigerating
one referred to; for there is implied in the latter not
only that the present conditions in the solar system
will continue, but that the environment of the solar
system will remain for so many millions of years what
it is. The matter is not alluded to here on account
of its humanitarian interest, but to point out that in
either case the results will be due to purely physical
conditions. What mankind would contemplate as a
dreadful catastrophe would be but the interaction of
huge machines, where energy was transformed on a
grand scale, and no particle of matter omitted for an
instant to conform to the three laws of motion.
PROPERTIES OF MATTER AS MODES OF MOTION 401
CHAPTER XIV
Properties of Matter as Modes of Motion
In the first chapter of the book only the most obvious
qualities of matter are considered, such as magnitude,
density, inertia, and so on, the properties which are
exhibited by masses of matter of visible magnitude
and form, from which the common notions concerning
its nature and possibilities have been derived. If one
stops his inquiries concerning the properties of matter
with these, and imagines that they are the ultimate
properties, and may rightly be assumed and asserted
of the individual atoms, he will be greatly in error; for
it is not difficult to show that nearly every property
of masses cannot be true of atoms, and that nearly
if not quite all material properties of what we call
matter, are derived from antecedent conditions, and are
resolvable into them or into mere relations which are
not inherent, and may be absent. It is, then, worth
the while to study the real significance of some of
the physical terms in common use, in order the better
to eliminate from the mind unessential qualities when
thinking of the inherent qualities of matter.
MATTER, ETHER, AND MOTION 402
During the past ten years laboratory facilities for
physical investigations have greatly aided inquirers, and
added much to real knowledge in this field. Some of
this knowledge is of such a character as will presently
make it needful for every one to reconstruct his notions
and explanations of physical phenomena, in order to
prevent hopeless confusion in his own thinking.
THE STATES OF MATTER.
Under the conditions of ordinary observations matter
is found in the solid, liquid, and gaseous states; the
solid state being that in which the molecules cohere so
strongly as not to be easily separated from each other
nor from the relative positions they have assumed with
reference to other molecules. Thus, a piece of granite,
as the type of a solid, may have its molecules cohering
to each other in certain positions, so strongly as to
require a ton’s weight to pull apart a section of one
square inch.
The granite is made up of small crystals of quartz,
mica, and feldspar, each having a definite chemical
composition. The individual crystals retain their relative
places for an indefinite time, and the atoms of the
individual molecules retain their relative positions for a
like indefinitely long time, else the crystalline structure
PROPERTIES OF MATTER AS MODES OF MOTION 403
would be lost, for crystalline structure implies definite
atomic arrangement as well as molecular arrangement.
So in solids the adjacent molecules are in what are
called stable positions, and are not easily separated.
In a liquid there is little cohesion among the
molecules, and no stable arrangement at all. The
individual molecules move among each other without
apparent friction, and the slightest force acting upon
them makes them to turn on any axis; and there is
good reason for thinking that in a liquid like water,
the individual molecules are continuously rolling and
tossing about with perfect freedom to move in every
direction. The phenomena of diffusion exemplifies
this. There is also good reason for thinking that the
individual atoms in the water are continuously changing
partners at a rapid rate, so if there were some means
for identifying the atoms of hydrogen and oxygen
in a given molecule, they might be seen presently
all separated and forming temporary constituents of
other molecules a relatively long remove from the first
position where they were observed. When the water
is frozen, that is has become a crystalline solid, this
freedom of atomic change and molecular rotations is no
longer recognized as a property. Molecular cohesion is
now exhibited where before there was none. There are
also new qualities called crystalline, hardness, density,
MATTER, ETHER, AND MOTION 404
and so on, which before this change did not belong
to it. The new qualities which seem to have been
developed are produced by lowering the temperature
of the water, that is, reducing the amount of kinetic
energy the molecules had; and by again imparting a
like amount to the ice both crystallization and cohesion are
destroyed.
A gas is a body of molecules in which the individuals
are free to move in every direction unconstrained by
any degree of cohesion, and where they are in frequent
collisions, bounding away in new directions through
distances usually many times the diameter of the
molecules themselves. Thus, in air the ordinary average
distance between impacts is nearly two hundred times
the diameter of the individual particles which, as before
stated, is in the neighborhood of one fifty-millionth of
an inch. Their continuous bumping against each other
and the walls of the containing vessel, produces what is
called the gaseous pressure. Increasing the temperature
of the gas increases the velocity of movement in the
free path, and, consequently, the momentum and the
pressure. It has been customary to say that heat
increases the elasticity of a gas, that a gas occupies the
whole space which encloses it, that a gas has a tendency
to indefinite expansion, and that the properties of a
gas are due to repulsive force among the molecules.
PROPERTIES OF MATTER AS MODES OF MOTION 405
In a loose sense such expressions may be allowed, but
they are not to be understood as correctly specifying
the qualities of the gaseous matter. It is not repulsion
that makes a ball move which has been struck by a
bat, but impact; and that it should continue to move
on until it strikes another body, follows from the first
law of motion, as true for a molecule of a gas as for
a baseball. The direction the ball takes depends upon
where it is hit, as well as upon how hard it is hit; the
velocity it has depends upon how hard it is hit, and
there is nothing peculiar to a gaseous particle requiring
the affirmation of different properties.
Some years ago improved methods of making a
vacuum were adopted, by which one could reduce the
amount of gas in a tube to even the hundred millionth
of its ordinary amount, so that a particle might have a
relatively long free path measurable in feet instead of
hundred thousandths of an inch, and the phenomena
of such rarefied gases were so new and surprising that
it was at first conjectured that a new state of matter
had been discovered, and it was called the fourth or
ultra gaseous state to distinguish it from the others;
but it was soon perceived that it was still only rarefied
gas, and that no new qualities had been developed,
and the same phenomena witnessed in the rarefied
gas were present in the denser, only disguised by the
MATTER, ETHER, AND MOTION 406
greater number of molecules which took part. So what
was called for a short time the fourth state has been
practically abandoned.
The three states already considered are known to
depend upon temperature. Thus, if ice or iron or
many other solids be heated they become liquid; if
heated still more they become gaseous. Some solids,
like wood, when heated do not assume the liquid
intermediate form, but are at once converted into a
gas; but different substances have different temperatures
at which they change from one form to the other.
Thus, water becomes a solid at 32 Fah., and a gas
at 212 Fah. Iron becomes fluid at 2, 800 and gaseous
at 6, 000. So far, then, it appears one might as properly
speak of iron as a liquid or a gas, as of water as
either, if they both may exist in the three conditions,
and no temperature is specified. We do not do that,
because when speaking thus ordinary temperatures are
implied, but seldom or never thought of. If one had
been brought up in the sun it is probable he would
never have seen a solid, and if at the moon, he would
know of neither liquid nor gas.
But the pressure of a gas is caused by the impact of
its molecules, and is proportionate to the temperature.
The law of Charles states what has been found to
be true within the limits of experiment; namely, that
PROPERTIES OF MATTER AS MODES OF MOTION 407
the volume of a gas is proportionate to its absolute
temperature; that is, temperature measured from an
absolute zero, in which case, it is plainly to be seen,
at absolute zero the gaseous volume would be nothing.
It does not imply that the matter of the gas would
be annihilated, but that the matter no longer existed
in its gaseous form; the individual molecules would
no longer have any free path motion, but would fall
to the floor of the containing vessel, and thus remain
quiescent, like so much dust. At absolute zero there would
be no gas.
Again, in the chapter on Chemism it is shown
how chemical reactions are determined by temperature,
and cannot take place in the absence of heat. The
late experiments of Pictet and Dewar show that as
temperature is lowered chemical reactions become
weaker and weaker, until some of the elements that
have very strong affinities at ordinary temperatures, and
so combine with energy, are incapable of combining,
and appear inert at such low temperatures as can
now be artificially made without great difficulty. Their
experiments confirm the conclusions given on page 291;
namely, that at absolute zero chemical affinity does not
exist. Molecules would not only fall apart, but their
individual atoms would no longer exhibit any cohesive
quality; and this, it will be perceived, would render
MATTER, ETHER, AND MOTION 408
the existence of such a thing as either a liquid or a
solid quite impossible, for each requires chemical action
for both molecular formations and cohesion in any
degree. Every kind of a structure would crumble to
atoms in a literal sense. Book, tower, mountain, ocean,
as well as every living organism, would completely
disintegrate, and lose every characteristic property
which had belonged to it. Hence, such qualities of
matter as would be absolutely emptied out of it by
simply reducing its temperature, cannot be considered
as essential qualities. Yet when the atoms were thus
deprived of what seems to us as all their useful
qualities, there is reason for thinking they would still
have definite form, mass, gravitation, magnetic and
electric qualities which, however, by themselves could
not make the mass of matter we call the earth a
habitable place, nor give to life a material habitat as it
now has.
It is then plainly evident that what we call solids,
liquids, and gases, with all the laws that belong to
each of them, are simply the relations of heat energy
to groups of atoms, not the properties or laws that
may be asserted of the atoms as such, and do not
need to be considered by one who is inquiring for the
essential endowments of matter.
There remains, therefore, an examination of the
PROPERTIES OF MATTER AS MODES OF MOTION 409
other so called qualities to see if, perchance, they too
may not, in a similar manner, be resolvable into energy
relations, which, in turn, may be absent.
MOLECULAR AND ATOMIC QUALITIES.
(HARDNESS.)
Substances vary greatly in what is called hardness,
and this properly serves, in many cases, to distinguish
one mineral from another. The mineralogist employs
a scale of ten, differing in degree from talc which
is the softest, to diamond which is the hardest, and
with these all other minerals are compared. But the
mineralogist tells us that this scale does not represent
hardness in any proportional way, because diamond
is as much as ten times harder than the ruby which
stands next to it in the scale; also that some diamonds
are so much harder than others, that no means has
yet been discovered for grinding and polishing them.
The diamond, however, is crystallized carbon, yet
carbon exists in another crystalline form called graphite,
or plumbago, which is soft, and may be whittled with a
knife, while coke, charcoal, and lampblack are forms of
precisely the same element, and these vary through the
whole range in hardness. What, then, does hardness
mean? Evidently it signifies the resistance offered to
MATTER, ETHER, AND MOTION 410
the separation of molecules from each other. It is the
measure of their cohesion, and could have no existence
in a single molecule of carbon. Furthermore, as has
been pointed out, as molecular structure can have no
existence at absolute zero for lack of energy needed
for maintaining cohesion, hardness cannot be a property of
atoms at all.
COLOR.
Color, either simple or compound, is exhibited by all
masses of matter—for white is but a mixture of wave
lengths, and no object is so black as to be invisible.
Gold is yellow, copper red, lead is bluish. The petals
of flowers, the feathers of birds, the gorgeous dyes of
the chemist, seem to impress us with an assurance that
color is a real quality of some kinds of matter, and
can be affirmed of it without any qualifications. Bodies
become visible either by their own luminousness as
when they are hot or phosphorescent, or by the light
reflected by them from some other source, as is most
commonly the case. When sunlight falls upon a rose
it is to be remembered that the sunlight is what we
call white light; it is made up of all wave lengths
which we can see. The rose petals absorb some of
these waves,—the blue, the green, and the yellow, but
PROPERTIES OF MATTER AS MODES OF MOTION 411
not the red; these are rejected by the surface, and they
therefore are reflected away, and testify to the selective
power of the petals, not their color, as can be found by
holding the same rose in yellow or blue light, when
it will appear black, that is, will absorb all offered
to it and reflect little or none. Again, when a body
is self-luminous, as, for example, a piece of burning
sodium which gives out a yellow light, it is to be
kept in mind that the yellow rays are produced by
certain vibratory rates which the atoms are compelled
for the time being to make, but which the atoms
will not make except on compulsion, that is, the high
temperature which the heat energy gives to it, and
therefore does not represent what can be called the
color of the body—only an artificial state of vibration.
Lastly, if all substances whatever were at absolute zero
in temperature, they would be setting up no ether
waves of any length, and could not effect any organ
of vision, and, consequently, would not only show no
color, but would be absolutely invisible. Hence color
cannot be affirmed of atoms.
IMPENETRABILITY.
It has seemed to nearly every one who has given
thought to the subject that what is called impenetrability
MATTER, ETHER, AND MOTION 412
must be a fundamental property of matter; that it was
axiomatic, if anything could be, that two masses of
matter could not occupy the same space at the same
time. This has been believed to be true, not because
it was demonstrable, but because it seemed to be
reasonable. Maxwell, however, calls it a vulgar opinion.
He further takes the pains to say, If hydrogen and
oxygen combine to form water, we have no experimental
evidence that the molecule of oxygen is not in the very
same place with the two molecules of hydrogen.1
When it is possible to make one, a mechanical
model is often of great assistance in helping one to
conceive of conditions which are more or less difficult
to describe in mere words; and a mechanical model
that embodies this possibility of the coexistence of two
atoms in precisely the same space may easily be made.
Roll up a length of wire into a loose helix or spiral
of any convenient length—say two feet long. Cut it in
two parts of equal length, and bend the ends of each
round until they touch, and fasten them thus, so as to
have two rings made of spirals of wire. Each one may
be taken as representing an atom of matter somewhat
similar to a vortex ring, which has been assumed as
the probable form of the atoms of matter. Each has
1See Art. Atom. Encyc. Brit., 9th ed.
PROPERTIES OF MATTER AS MODES OF MOTION 413
form, size, and various other qualities, but if one of
them be pressed down upon the other it will be found
they will make room for each other, so that as rings
they both occupy precisely the same space. This is not given
here as anything more than as, possibly, a helpful
suggestion as to how a seemingly impossible condition
may be true. Evidently in this case the difficulty lies
in the assumption that an atom of matter is a hard,
impenetrable, geometrical solid, and, as Maxwell says,
there is no proof that such is the fact. Impenetrability is
an unwarrantable assumption.
ELASTICITY.
Elasticity has been assumed to be a fundamental
property of atoms, and so not derivable from physical
conditions underlying it; but Lord Kelvin has shown
good reason for thinking that elasticity is a derived
quality, for it is possible to construct models which
exhibit the phenomenon in a high degree while they
are in motion, and not at all while they are at rest. A
number of gyroscopic disks set whirling on a circular
axis, shows this in a remarkable way, and suggests on
inspection, that something like such an arrangement may
be the complete explanation of the quality as exhibited
by atoms. A vortex ring may be considered as a large
MATTER, ETHER, AND MOTION 414
number of revolving disks on a circular axis, which
will give to the ring not only rigidity, but stability of
form, any departure from which will be resisted by the
mechanical structure, and it will return to its original
form after the deforming stress has ceased, with a rate
depending upon the rate of rotation of the constituent
Diag. 36.
parts of the ring. On page 47
reference is made to the behavior
of a rotating disk, and how it
simulates this property of elasticity.
The common gyroscope may be
cited as exhibiting it in a manner
that depends upon the way in which
the disk is mechanically mounted.
An ordinary whirling disk can
be freely moved only in its plane
of rotation, or planes parallel to
that. Any attempt to change the
angle of the axis is mechanically
resisted. This may be understood
by reference to diagram where a b
is a disk capable of rotation on axis c d. While rotating,
it can move freely in the plane a b, but any attempt
to tip the axis in any direction will be resisted by
it. Imagine, then, a large number of similar disks,
mounted on a circular axis, as in diagram 36, each
PROPERTIES OF MATTER AS MODES OF MOTION 415
one rotating. It is plain that any attempt to tip the
ring in one direction or the other, or to change the
form of the ring itself, supposing it to be flexible, will
necessarily change the plane of some of the revolving
disks, and will be resisted as a whole, for the same
reason that one of its parts will do the same. It will
be seen that if all these disks be rotating in the same
direction the movements will be like those of a vortex
ring. If additional disks could be inserted upon the
axis, so as to form a continuous body quite round
the circular axis, it would constitute a ring; and if
the proper rotation were set up, it would possess all
the qualities of a vortex ring, and elasticity would be
a prominent quality, as stated on page 45. It is no
longer necessary, if it ever was, to assume elasticity
as a fiat quality, imposed upon atoms which might
have existed without it; for the laws of motion, acting in a
properly constructed mechanism, are quite sufficient to produce
it.
MAGNETISM.
On page 246 the statement is made that magnetic
phenomena have led to the belief that all atoms of all
kinds of matter are magnetic, and are only obscured in
ordinary matter by the molecular arrangements which
MATTER, ETHER, AND MOTION 416
tend to neutralize the magnetic fields of the individual
atoms. Attention is again invited to the diagrams
on page 245, with the accompanying description, in
order to freshly bring to mind how vortex motion
necessarily produces what is called polarity—the two
sides of the ring have different qualities. On one side
the movements are all inwards, on the other outwards,
and from these the phenomena of apparent attraction
and repulsion necessarily follow. But beyond this, once
assume that individual atoms are magnets by virtue
of their constitution, and that every magnet has a
magnetic field infinite in extent, within which it can
affect other atoms, one can see at once that every atom
in creation has a magnetic hold upon every other atom,
because every one is in the magnetic field of every
other one. This effect is not necessarily one of attraction
or repulsion tending to move one mass towards or
away from another; but, on the other hand, it tends to
rotate each on an axis so both shall face the same way.
So long as there is no change in position or in form
of such a magnet, the magnetic field will be uniform;
but if the form be changed in any way the whole field
has to change in conformity with it, as described on
page 302, and such vibrations as constitute the heat of
an atom are really the change in form of the atom, and
this, therefore, changes necessarily the whole magnetic
PROPERTIES OF MATTER AS MODES OF MOTION 417
field of the vibrating body. These changes in the field,
which originate in this way, are what are called ether
waves. When the waves are produced slowly, by an
alternating dynamo current, or more swiftly by some
of the methods so ingeniously devised by Hertz and
Tesla, they are called electro-magnetic waves. When
produced so swiftly as to have a wave length only the
one thirty-thousandth of an inch, they have been called
heat waves; and when the waves are so short as to be
capable of affecting the retina of the eye, they are called
light waves, though there is no distinction between
any of them except in their length. The vibrations of
the atomic magnet are rapid because it is small; the
waves it produces are changes in its magnetic field
in the ether, so one may trace back in this manner
the phenomena of light, of heat, and electricity, to the
mechanical structure of atoms; and it is mechanically
intelligible too, and, like the preceding accounts of
properties, it appears that magnetic and electric qualities
are due to the peculiar kinds of motion embodied in the atoms,
and cannot be considered as particular endowments of
a something called matter, which it might have been
without.
MATTER, ETHER, AND MOTION 418
INERTIA.
The inertness of matter has been touched upon on
page 84, and here may be added the consideration of
what interpretation could be put upon such phenomena
as are exhibited by such a device as is represented by
diagram 36, supposing it were enclosed in a box so
one could not see the mechanism? The box enclosing
it would exhibit a new quality of the nature of inertia,
by virtue of the motions within it, which it would
lose as the friction diminished the rate of motion, and
when this stopped altogether the property would no
longer be present. Hence, inertia, too, must be looked upon
as probably due to motion.
MASS.
Mass, as a property of matter, is generally defined
as the amount of matter considered, and is measured
by what is called acceleration, that is, the velocity it
acquires in a second when acted on by a constant force or
push. Amount of matter is a very indefinite expression,
but is often convenient, and seldom misleading when
one is considering a given weight of a substance.
One may speak of a pound of iron or of hydrogen
as a mass of iron or of hydrogen, meaning a definite
PROPERTIES OF MATTER AS MODES OF MOTION 419
weight made up of a very large number of molecules
of one or the other element; but if one will think
of the atoms of these, and endeavor to form an idea
of what can be the physical meaning of mass, when
applied to one of them, he will at once see that the
term carries with it no conception whatever of the
physical difference between atoms of different kinds.
An atom of iron is said to contain fifty-six times the
mass of an atom of hydrogen, while an atom of gold
has a hundred and ninety-six times the mass of the
hydrogen atom, and all the elements differ in mass
in the ratio of their atomic weights. Can any one
suppose for an instant, that an atom of gold is a
hundred and ninety-six times larger than an atom of
hydrogen? There is some evidence that atoms differ
somewhat in magnitude from each other, but none of
any such difference as is represented by their atomic
weights. Furthermore, this would imply that atoms
were blocks of some primeval stuff of uniform quality,
and that atoms of a given element were but uniform
volumes of it; and it hardly needs to be said that
such a view is negatived by all we know, for the
properties of the various elements do not vary simply
with their weights, as would be the case if they were
thus constituted. Hence, mass as applied to atoms
cannot be thus conceived. It is possible to form a
MATTER, ETHER, AND MOTION 420
conception of the physical meaning of mass as applied
to atoms or molecules, by recalling the phenomenon of
rigidity in position, which is the outcome of rotations,
as described on pages 47 and 414, for the amount of
effort needed to move such a rotating body depends
not simply upon the amount of rotating material, but
its velocity of rotation; so a small amount of material
with a high speed may offer as great a resistance to
movement from its position as another much larger
amount of material with corresponding slower rate,
but otherwise the two would necessarily have great
differences in their other properties; thus their rates of
vibration would be very different, because their degrees
of elasticity would be different.
One may then assume that such differences between
the atoms of the elements as are called their masses, are due to
the relative rates of rotation. This, of course, on the
fundamental assumption that the atoms themselves are
vortex rings such as we have argued as being highly
probable.
GRAVITY.
There now remains to be considered one more
general property of atoms and all combinations of
them; namely, their gravitative property. If one be
PROPERTIES OF MATTER AS MODES OF MOTION 421
content to say that not enough is known about it to
warrant even a tentative opinion, and, therefore, refuses
to draw any inferences from what is known as to
what gravitative property is, or is like, one need to
have no quarrel with such an one; but if, on the other
hand, one is interested in fundamental questions, and
thinks that whatever be the truth about gravitation or
any other unsolved problem, when it is known, it will
be seen to be in harmony with every other physical
truth, and will, therefore, be a consistent part of the
body of physical knowledge which we now possess,
such an one will perceive that with the banishment
of the old notions concerning the structure of matter,
with its endowments of sundry properties which might
have been otherwise, or that the matter we know
might have had entirely different properties, must also
go the notion of quality endowments in any such
sense as was formerly held. He will also have good
reason for holding it altogether probable, that if the
other properties of matter are reducible to modes of
motion, so the last one in the list will be found to be
reducible to the same factor. If the others have been
interpreted thus, one after another yielding as molecular
phenomena became better understood, he will conclude
that if the problem of gravitation has not been solved,
as the others have been, it is not because it is insoluble
MATTER, ETHER, AND MOTION 422
in itself, but because it is inherently more difficult, or
has not received the degree of attention that has been
given to other problems since conservation has been
discovered and forms a part of every discussion.
One thing seems certain, if the vortex-ring theory of
matter be true, or anything like it, then gravity must
follow from the structure; for in the absence of any
evidence of the existence of gravitation in the ether, no
one is at liberty to postulate it there for the sake of
finding it in the atoms. It must be looked for as due
to the particular kind of motion that constitutes the
atom, and is constant because that motion is constant.
In the chapter on gravitation is given a mechanical
conception of gravitative conditions which, whatever
may be its inadequacy, is consistent with other physical
knowledge. Faraday, as is well known, made several
efforts to discover some relation between gravitation
and electricity, but only negative results were reached.
He was not discouraged by his lack of success, and
had planned still other experiments, which he was not
able to finish. He always worked on some hypothesis
almost always radically different from the hypotheses of
his scientific contemporaries, and time has vindicated
his rather than theirs; and that there must be some
physical relation between the two classes of phenomena
was one of his, and so it seems to-day; for if gravity
PROPERTIES OF MATTER AS MODES OF MOTION 423
be due to the form of motion in the atom, and if an
electric current in a circuit represents a real vortex ring,
having the conductor for its core, then it seems likely
there is some gravitative effect between such current
and the earth; but it may be so slight with a single
circuit as to not be detectable with present means, and
the mutual gravitative effects between two such circuits
would be obscured by their electro-magnetic effects.
Lastly, if the atom itself be a vortex ring, as
explained in the chapter on the ether, it follows that in
the absence of such form of motion there would be no
atom—no matter, though the substance out of which
the ring was constituted would exist, but without any
of the characteristics that we assign to matter in any of
its forms. If one chooses to call a common smoke-ring
alpha, evidently when the ring is dissipated there is no
more ring, there is no alpha, it has been annihilated
as a ring; and in like manner, one may understand
that what constitutes an atom is not so much the
substance it is composed of as the motion involved in
it. Such an atom is a particular form of motion of the ether in
the ether, in the same sense as what is called light is a
form of motion of the ether in the ether. One is an
undulation, the other a vortex. One we call an ether
wave, the other we call matter: both involve energy,
and both have properties. Thus, one after another of
MATTER, ETHER, AND MOTION 424
the properties of matter are found to be resolvable into
ether motions, ether being the primal substance, and
matter only one of its manifestations.
Such a conception of matter as is here presented,
resolving as it does all its physical properties, even
itself, into modes of motion of the ether in the
ether, is not simply a new conception of matter,
it is rather a revolution in fundamental conceptions,
and if trustworthy, necessitates an abandonment of
nearly every notion concerning them which men have
entertained when thinking and discoursing upon the
subject. The mystery of phenomena is not lessened but
made greater by the discovery that everything which
affects our senses in every degree is finally resolvable
into a substance having physical properties so utterly
unlike the properties of what we call matter, that it is
a misuse of terms to call it matter.
No one in the past has been able to forecast its
properties. The necessity for such a medium has not
been felt by many philosophers, and though there
has been some expectation on the part of a few, any
new step has been a source of surprise. For instance,
when Hertz succeeded in producing electro-magnetic
waves in the ether only two or three feet long, it was
heralded as being a demonstration of the existence of
the ether, implying that all the phenomena of induction
PROPERTIES OF MATTER AS MODES OF MOTION 425
and electro-magnetic waves developed by machines
vibrating up to four thousand per second in telephonic
apparatus, could have some other interpretation. The
point here emphasized is that the properties of the
ether and their relations to such physical phenomena as
have been the subjects of research are so little known,
that no one has yet ventured to embody them in an
all embracing philosophy, so as to deduce apparent
phenomena from them.
The significance of this will be apparent when one
recalls the various attempts of materialistic philosophers
to explain all sorts of phenomena as due to matter and
its properties. Some of them have been ignorant of the
existence of the ether; others have grouped matter and
ether together and called both matter, and considered
both as subject to the same laws as are found to
hold true for matter as defined in this book. When
it is apparent that such physical views are radically
unsound, that one cannot reason from our perceptual
matter to imperceptual ether,—for it is true that there
are no known nerves that respond directly to ether
action,—it will also be apparent that any scheme of
things that ignores this knowledge or fails to make
proper distinctions here cannot be entitled to respectful
consideration. Indeed, such physical materialism is less
rational than ever, for it ignores much knowledge now
MATTER, ETHER, AND MOTION 426
in our possession which is as certain as any we possess,
and it ignores the trend of all the physical knowledge
we have; for it cannot be denied that the advance in
knowledge which has been so marked during the past
half century has been in the discovery of the simplicity
of relations, rather than towards ultimate explanation.
It may truly be said that, in a philosophical sense,
nothing has been explained. Familiarity with constant
phenomenal relations induces in us expectations of
certain happenings, and presently they seem obvious.
The car moves because the engine pulls it; the engine
moves because the steam pushes it; the steam pushes
because the heat pushes it; and the heat pushes
because—it is the nature of heat to do work. In that
way, every physical phenomenon runs at last into an
inexplicable, into an ether question; and the necessity
for it follows from nothing we know or can assume.
No one may assume for an instant that the possibilities
of ether phenomena are limited by such interactions as
have hitherto found expression in treatises on physics.
Indeed, there is already a body of evidence which
cannot safely be ignored, that physical phenomena
sometimes take place when all the ordinary physical
antecedents are absent, when bodies move without
touch or electric or magnetic agencies,—movements
which are orderly, and more or less subject to volition.
PROPERTIES OF MATTER AS MODES OF MOTION 427
In addition to this is still other evidence of competent
critical observers that the subject-matter of thought is
directly transferable from one mind to another. Such
things are now well vouched for, and those who have
not chanced to be a witness have no a priori right
from physics or philosophy to deny such statements.
Such facts do not in any way invalidate physical laws,
nor make it needful to modify present statements
concerning energy. Physical laws are not compulsory;
they rule nothing; they are but statements of our
more or less uniform experience. If these things be
true, they are of more importance to philosophy than
the whole body of physical knowledge we now have,
and of vast importance to humanity; for it gives to
religion corroborative testimony of the real existence of
possibilities for which it has always contended. The
antecedent improbabilities of such occurrences as have
been called miracles, which were very great because
they were plainly incompatible with the commonly held
theory of matter and its forces, have been removed,
and their antecedent probabilities greatly strengthened
by this new knowledge; and religion will soon be able
to be aggressive with a new weapon.
MATTER, ETHER, AND MOTION 428
CHAPTER XV
Implications of Physical Phenomena
A physical phenomenon is a phenomenon which
involves energy. Every change of condition in matter is
brought about by the action of energy upon it in one way
or another. It may be gravitative energy or heat or light
or electric or any other; but every physical change has
a physical antecedent as well as a physical consequent,
and the explanation of any given phenomenon consists
in pointing out the precise antecedents that brought
it about. There is a common saying that like causes
produce like effects, but this is far from being true
in the popular sense. If it were true the development
of science would not be the difficult and painfully
slow process it has proved to be. Electricity may be
produced by turning a crank, by dissolving a metal,
by twisting a wire, by splitting a crystal, and in others
ways. The product is the same, but the antecedents
are so different that no one can tell by examining the
product how it was produced. If it became important
to know what caused the electrical phenomenon, it
would not be sufficient to know that electricity could
IMPLICATIONS OF PHYSICAL PHENOMENA 429
be produced in these different ways; one would need
to know the specific apparatus employed. The more
complicated the phenomenon the more difficulty there
is in unravelling it.
So far as experiment and experience have led us,
the antecedents of every physical phenomenon are
themselves physical, and more than that, all reactions
are quantitative, that is, the product is proportional
to the antecedent, and this is sometimes embodied
in what is called the doctrine of the Conservation of
Energy which every one knows about.
The exchange relations between the different forms
of energy,—mechanical, thermal, chemical, electrical,
etc., which are so well-known, being quantitative, are
therefore mathematical. They have therefore become a
corporate part of the body of knowledge, and are no
longer subject to any questions as to their validity under
any circumstances whatever. One who should challenge
them would no more be deserving of attention than if
he should offer to prove he could square a circle.
The fundamental postulates of physical science are
binding upon the one who understands them, for the
same reason that the multiplication table is. There are
no contingencies and no possibilities of hedging. If
any one of them could be overthrown the whole body
of science would go with it. This is said because there
MATTER, ETHER, AND MOTION 430
are not a few who appear to think that what is called
physical science may not be so certain as its advocates
think, and that there may be factors which have not
yet been reckoned with that may quite transform the
whole scheme. Science is a consistent body of relations,
not simply a classified body of facts. These relations
have been discovered by experiment, not by deduction.
Some of them are the following:—
1. Physical changes affect only the condition of
matter, not its quantity. One cannot create or annihilate
it, nor can one element be changed into another.
2. Every atom is continually exchanging energy with
every other atom, the rate of the exchange depending
upon their difference in temperature.
3. The different forms of energy are transformable
into each other, but the quantity of energy is not
altered by the transformation.
4. Complex organic molecules differ from simpler
inorganic molecules in possessing more energy. The
differences in this respect are definite, may be measured
in foot-pounds, and are practically enormous.
5. Every physical change has a physical antecedent,
is therefore mechanical, and is conditioned by the laws
of energy.
These principles are the outcome of modern investigation,
the evidence for them is overwhelming, and
IMPLICATIONS OF PHYSICAL PHENOMENA 431
a working knowledge of them needs to be a part of
the mental equipment of every investigator, especially
of the one who takes it as his province to explain
phenomena.
Science is strong here if it is anywhere; and any
description of any event, any explanation of a genuine
phenomenon that practically ignores these, cannot be
true, and can have no claim to consideration.
Before any explanation is needed there is always the
advisibility of ascertaining that the alleged event really
happened, and whatever is not professedly miraculous
must not be in discordance with the bast knowledge
we have.
With the above principles in hand one is prepared to
fairly judge as to whether a given statement is credible
or not. It is not necessary, as some seem to suppose,
that one should be able to explain a phenomenon if
he rejects the explanation of another one, or to assert
with emphasis whether a thing is possible, probable,
or impossible.
In La Fontaine’s fable the philosophers were at the
theatre witnessing a play in which Phoebus rose in
the air and disappeared overhead. They undertook to
explain the phenomenon. One says Phoebus has an
occult quality which carries him up. Another says he
is composed of certain numbers that make him move
MATTER, ETHER, AND MOTION 432
upward. Another says Phoebus has a longing for the
top of the theatre, and is not easy till he gets there. Still
another says Phoebus has not a natural tendency to fly,
but he prefers flying to leaving the top of the theatre
empty. Lastly, a more modern philosopher thinks that
Phoebus goes up because he is pulled up by a weight
that goes down behind the scenes. The last is an
explanation. From a physical standpoint the others are
not simply inadequate explanations, they are absolute
nonsense. They make the antecedents of a phenomenon
involving energy, factors that have no more relation
to energy than has moonshine to metaphysics. Yet
there has been a large number of men in all ages,
men able in many ways too, who have ventured to
explain phenomena in such a non-sequitur way, and
who have spurned the mechanical philosopher and his
explanations.
In that class of phenomena called spiritualistic
there is a large body of reputed physical phenomena,
vouched for by large numbers of witnesses, such as the
movements of furniture, chairs, tables, books, pianos,
etc., the playing upon musical instruments, guitars,
accordions, pianos, the appearance of lights, of faces, of
full forms clothed, of conversations with materialized
spirits, and so on, in great variety.
I suppose no one doubts that to move a body of any
IMPLICATIONS OF PHYSICAL PHENOMENA 433
magnitude requires the expenditure of energy, and to
do a definite amount of work requires always the same
amount of energy, yet I suspect there are many persons
who give credence to statements of occurrences which
practically deny the above proposition, thinking it to
be probable that spiritual agencies may have control of
powers that mankind knows nothing about. This may
be true enough, but the question is not as to what
this or that agency can do, but whether if spirits do
a certain kind of work it takes less energy than if a
man should do the same thing.
Whenever a weight or a resistance and a velocity
are given, it is always possible to compute the energy
spent to produce or maintain it. Let us study a case
or two. In olden times it was related that one of the
prophets was carried through the air by the hair of
his head from Babylon to Jerusalem. In later times it
was said that Mrs. Guppy was similarly transported
from Edinburgh to London. The distance is about 400
miles, and if I remember rightly she made the transit
through the air in less than one hour. This makes
the velocity to be about seven miles a minute or 600
feet per second, which is three times faster than the
highest tornado velocity. The resistance offered by the
air to the movement of bodies in it is very well known.
Pressure in hurricanes has been observed as high as 90
MATTER, ETHER, AND MOTION 434
pounds per square foot, and as the pressure increases
with the square of the velocity, it follows that at 600
feet per second the pressure per square foot would be
about 800 pounds; and if the exposed surface of Mrs.
Guppy was no more than six square feet, the total air
pressure must have been not less than 4, 800 pounds.
Now, the energy of this is found by multiplying the
pressure by the velocity per second.
4, 800  600 = 2, 880, 000 foot-pounds,
and as a horse-power is equal to 550 foot-pounds per
second, it follows that it took not less than
2, 880, 000
550
= 5, 236 horse-power
to move Mrs. Guppy in that way at that rate.
It was reported when Madam Blavatsky was living
that she was in the habit of receiving letters from
distant correspondents, brought to her by some occult
agency and dropped upon her table. These letters were
said to have been written only a few minutes before by
persons living in the most distant parts of the earth.
It takes but a little figuring to discover the amount
of energy necessary to do a work of this kind. Thus,
let the distance be 10, 000 miles, the time ten minutes.
The pressure per square foot due to such a velocity in
IMPLICATIONS OF PHYSICAL PHENOMENA 435
the air will be 17, 000, 000 pounds, or 118, 000 pounds per
square inch. Assume but one square inch as the area
exposed to such a pressure, then the energy needed to
transport it with the speed of 16.6 miles per second,
will be
118, 000  5, 280  16.6
550.
= 18, 000, 000 horse-power.
Unless such packages were protected by occult
agencies also, they would be burned up before they
had gone the first mile of their journey.
The popular idea is that at death the spirit leaves
the body, but that it may, and often does, remain in the
locality, and is frequently in the presence of its friends,
unperceived by them, though occasionally they may
be seen and communed with through the agency of
certain preternaturally gifted persons called mediums.
This proposition has so many physical data, and
involves so many physical implications, it will be worth
the while to look squarely at some of them.
1. A spirit is supposed to be a conscious entity
dissociated from matter, having ability to move at will
and to be more or less interested in what is going
on in the world, and capable of giving information
on matters remote from observation or the knowledge
of men. Suppose then such an entity, a disembodied
spirit, without a corporeal body, but anxious to be in
MATTER, ETHER, AND MOTION 436
the neighborhood of its former friends. Seeing that
it now has, according to this view, no longer a hold
upon matter, it has ceased to be in any way affected by
gravity and inertia, for these are attributes of matter.
Now the earth has a variety of motions in space; it
turns on its axis, so that a point on the equator is
moving at the rate of a thousand miles an hour. It
revolves about the sun at the rate of nearly seventy
thousand miles an hour, and with the sun and the
rest of the bodies that make up the solar system it is
drifting in space at the speed of sixty thousand miles
an hour or more, so that the actual line drawn in
space by any point upon the earth is a highly complex
curve drawn at the rate of upwards of a hundred and
twenty-five thousand miles in an hour. Now, any object
whatever keeping up with the earth, but without the
help of gravity, must maintain the velocity in space
of not less than a hundred and twenty-five thousand
miles an hour, and that is not all, as the movement
is not in a straight line, any such object wishing to
keep in a particular locality, say a room, would have
to be on the alert constantly, for the earth wabbles for
numerous reasons and what seems to us, who have
bodies held by gravitation to the earth, as so quiet
and smooth running that we are never conscious of
the motion for an instant, is so simply because gravity
IMPLICATIONS OF PHYSICAL PHENOMENA 437
takes care of us. Once surrender that and undertake
to depend upon some supposed private source of
energy, and one would instantly discover he had an
engineering problem of a high degree of complexity.
If one assumes, as some have done, that such spirit is
composed of, or associated with, some sort of matter,
and that navigation is accomplished by an act of the
will, it will not change the foregoing factors in the
problem at all.
2. Suppose, as some have done, that disembodied
spirits lose their hold upon matter, and that they do
not remain at the earth. Then, if they remain at the
point where separation from the body took place, in an
hour the earth will have moved forward one hundred
and twenty-five thousand miles. But over the earth
there is certainly a death every minute all the time,
and such are left in the rear by the earth never to
return to them, for the movement of the earth is not
a circuit, but an apparently endless drift. Think of the
dead of the earth for the thousands of years since man
has lived upon it! On this view, the spirits might be
seen like the tail of a comet reaching backwards for
millions on millions of miles,—the trail of the dead.
In any view, time and space and energy cannot be
ignored or ruled out.
At s´eances the reported phenomena are mostly of
MATTER, ETHER, AND MOTION 438
a physical sort, the trance of the medium being
a physico-mental phenomenon. The phenomenon of
sound implies the expenditure of energy, it is a vibratory
motion of the air or other elastic body, and in order
to produce it some antecedent force must be spent; it
may be produced by mechanical means, or heat, or
electricity, or by the muscles. Its production does not
imply any specific method any more than articulate
speech implies a person, as Faber’s talking-machine
and the phonograph prove.
Let us consider some of the more subtle phenomena
that are reported. First, as to so-called conditions. One
of the primal ones of these for such phenomena as the
movements of bodies and materializations, is said to be
darkness. This is of so much importance that it must
be fully attended to. To one who has not paid any
attention to what has been done in molecular science
within the past fifteen or twenty years, the phenomena
of light may and probably do seem to be due to an
unique agency, as much as heat or electricity; and
therefore he looks upon light as he looks upon the
others in the hierarchy of the physical sciences, and
expects that in its absence a potent agency or kind of
energy is lacking. That this idea and conclusion is all
wrong will be apparent when it is recognized that what
we call light is a particular sensation in the eye, and
IMPLICATIONS OF PHYSICAL PHENOMENA 439
that to produce the sensation there is no one antecedent
that is essential. Press the eye with the finger in the
darkest night and one will see a ring of light with
great distinctness. An electric shock, a bump upon the
head, will also give one the sensation of light, and in
the absence of other aids to a judgment no one could
tell what was the antecedent of a given light sensation.
Radiations from a luminous body, and reflections
from a non-luminous one, were not long ago thought
to consist of three different kinds of rays,—heat, light,
and actinic rays. It has been discovered that there is no
such distinction in fact. What a ray will do depends
upon what it falls upon. The same ray that falls upon
the eye and produces the sensation of light, would
heat another body, or do photographic work. The only
difference in rays is in their longer or shorter wave
lengths, and the energy of a wave does not depend
upon its length. From this it follows that there is no
such thing as light as distinguished among forces or
forms of energy. Light is a sensation, and in the absence
of eyes no such distinction could possibly be discovered.
Light, then, as a particular kind of agency takes no
part in phenomena outside of the eye. The eye of man
is adapted to respond to certain wave lengths, the eyes
of other animals are adapted to respond to other wave
lengths; and if our eyes were adapted to perceive all
MATTER, ETHER, AND MOTION 440
wave lengths the whole universe would be always light
about us, every object, whatever its temperature, could
always be seen as easily as we now see when the sun
shines.
These facts make it quite impossible for a physicist
to understand why darkness should be an essential
condition for the occurrence of such phenomena as are
described. Again, every ray of light when traced back
leads to a vibrating molecule or atom. Indeed, light
or ether waves in general all imply vibrating atoms
or molecules; and what is called spectrum analysis is
but a development of this fundamental principle, and
not only the kind of matter, but its physical condition
is revealed. If Moses had had a spectroscope when
he saw the burning bush it might have told him the
nature of that conflagration.
So when luminous forms appear at a dark s´eance,
there is first the ether waves of such length as to affect
the eye; these traced to their source must arise from
vibrating molecules, that is, matter expending energy
in the production of ether waves; for no matter ever
shines without some source of energy.
If the matter that gives out the light be ordinary
matter, there is no difficulty in understanding it; for
matter can be made to shine in several ways,—by
impact, by high temperature, by electric vibrations, by
IMPLICATIONS OF PHYSICAL PHENOMENA 441
chemical reactions; and no one could tell from the
simple fact that the matter shone, what the origin
was. But it is said that these forms that are seen and
thus affect the eye, that are touched and thus affect
the sense of touch, that are warm and thus testify to
vibrating molecules, that speak and appeal to the ear
through air vibrations, are materializations; meaning by
that that the body with its various organs and their
functions is built up de novo out of material at hand, as
Adam was said to be made of the dust of the ground,
and as the lion that pawed to free its hinder parts
from the soil out of which it thus grew. What are
the materials that make up a human body? Ultimately
there are carbon, hydrogen, oxygen, nitrogen, iron,
phosphorous, sulphur, potassium, sodium, and several
other ingredients of less importance. From a hundred
to a hundred and fifty or more pounds of these are
needed for one full-grown person.
Many of the materializations that have been described,
from Samuel the prophet to Katie King, have appeared to
be veritable specimens of humanity even to avoirdupois
and all that is implied in that. If the matter of such
bodies was a creation and not a collocation, then one
of the fundamental principles of physics is simply not
true; for matter can be created and annihilated by any
spirit that knows how to find a suitable medium. If
MATTER, ETHER, AND MOTION 442
the material is gathered from the environment—and
this sometimes is asserted—then the difficulty is nearly
as great.
One must take notice of the difference there is between
inorganic or relatively simple chemical compounds and
those that make up the bodies of living things,—the
bones, the tissues, the muscles, the nerves, the brain, the
blood. For building up a single pound of such tissue
as muscle or of fat requires the expenditure of energy
represented by about sixteen million foot-pounds; and
as in such a body as we are supposing there could
hardly be less than twenty-five or thirty to be so
reckoned, it follows that not less than four hundred
million foot-pounds of energy is necessary, a quantity
equal to upwards of twelve thousand horsepower, if
done in a minute; and if done in half a minute,
then twice that quantity. I cannot but wonder if
those who think they have witnessed such phenomena
could have been conscious of the stupendous amount
of energy which was being evolved before their eyes.
Then dematerialization involves the annihilation of the
same amount; for it is to be remembered that organic
matter differs from inorganic in the amount of energy
absorbed. There has been either the creation and
annihilation of matter or the creation and annihilation
of an enormous amount of energy, without antecedents
IMPLICATIONS OF PHYSICAL PHENOMENA 443
and with no residuals. This is not saying that such
events have not taken place, it only points out the
factors of energy which are implied if they do happen.
One who is unaware of such implications and
phenomena may easily suppose the most improbable
things can take place. Those who are aware of
such implications cannot hear of such events without
instantly perceiving how almost infinitely improbable
they are.
Reports of such phenomena have never come from
any man who understood the relations of phenomena.
Scientific men have been often told of their incompetency
to investigate so-called psychical phenomena;
but if the latter involve physical phenomena, then who
else can properly investigate them?
This paper is not to be understood as implying that
there is no relation between the living and the dead,
for the writer does not believe that doctrine; instead
of that he thinks we are very near to a discovery of a
physical basis for immortality that will transform most
all our thinking. If spiritual communication is not
accompanied with physical phenomena in the alleged
way, it does not follow that it may not happen in other
ways that do not do such violence to our fundamental
knowledge as most of the reported cases do. The
universe is large, not much of it has been explored. We
MATTER, ETHER, AND MOTION 444
live and move and have our being in an environment
about which our knowledge is most meagre; but our
knowledge of energy we get not only from the earth,
but from the sun and most distant stars and nebulæ,
and it is not probable that any contribution whatever
will materially modify our present knowledge of it.
Thus far I have considered what is always implied
when physical phenomena are considered, especially
with reference to the antecedents; for instance, when
a steam-engine is run it implies the consumption of
fuel, which in turn implies molecular structure, and a
definite amount of energy in what is called its chemical
form. That energy is not created or destroyed by any
physical process, and, therefore, every exhibition of
energy, no matter where or when, is to be explained
solely by reference to the laws of energy which are
now so well known as to have passed out of the
region of conjecture or hypothesis. If there be any
knowledge which man possesses, which for certainty
and accuracy compares with mathematical knowledge,
it is the knowledge of physical relations. I traced out
a few cases in which the alleged phenomena were
of such a physical sort as to be easily handled, and
showed how one must look at their antecedents. That
such phenomena did take place was not denied. It was
simply asserted that when they did happen one must
IMPLICATIONS OF PHYSICAL PHENOMENA 445
reckon with the implications, unless he was prepared
to affirm that physical phenomena might happen when
physical laws are ignored and quite counted out. There
are yet some further implications it is well to consider.
They have to do with the objective structure and
qualities of the spiritual beings that are supposed to
bring about the phenomena we are considering, such
as moving objects, playing upon musical instruments,
writing upon slates, and so on.
As such beings are always addressed as if they
were visible personages, possessing the same organs
of hearing, seeing, and so on, as are possessed by
individuals still having a material body; and as the replies
to questions never contradict such assumptions, but,
on the contrary, are confirmatory of such assumptions,
it follows that one may properly consider what really
is implied in the assumption that spirits have eyes and
ears, because they can see and hear. When I say I
see, I assert not only the existence of what we call
light, but the existence of an organ called the eye,
the structure of which is adapted to be acted upon
by what we call light. Light is, as we all know,
a wave-motion in the ether. It travels at the great
velocity of a hundred and eighty-six thousand miles
in a second, and the waves are in the neighborhood
of only the one fifty-thousandth of an inch long. The
MATTER, ETHER, AND MOTION 446
eye is the only structure in the body that can perceive
these waves. It is a kind of camera, and photographic
work goes on in the retina very much as it does in
the process of photography. Then, there is the optic
nerve, which is an essential part of the apparatus, and
conveys to the seat of consciousness the impress of the
molecular disturbances which have taken place in the
eye. No one is conscious of the phenomenon of light
except through the action of this complex mechanism.
Therefore, when one says he sees, he means that a
particular kind of disturbance has taken place in a
particular physiological structure. The term sight is
never used in a different sense from this, except when
it is avowedly used figuratively. In the absence of ether
waves there could no more be what we call sight than
if there were no eyes; both are essential.
When, then, it is said or admitted that a spirit sees,
not in a figurative sense, but in the sense in which we
all use the term, it is implied that a spirit has eyes,
a physiological structure, acted upon by ether waves,
and the nervous system behind that. It has what we
call eyes. It will not do at all to say that such spirit
has an equivalent sense, for whatever that might be
it would certainly not be sight. One may get a very
accurate knowledge of the presence of another person
by the voice, or by the sense of touch, but it would be
IMPLICATIONS OF PHYSICAL PHENOMENA 447
a culpable misuse of language to say of such person
that he was seen. Sound can no more affect the eyes
than light can affect the ears. This, then, is the same as
saying that a spirit has a physical structure for seeing
similarly constituted to that in man, and, indeed, in
all organizations that see.
When I say I hear, I mean that air vibrations have
affected my organs of hearing, the ears with the
nervous structure between the ear and the seat of
consciousness. There is implied in the statement not
only that sound vibrations of a definite sort have been
produced and are acting, but that they are acting upon
a certain physiological structure adapted to be affected
by gaseous vibrations. Vibrations in the ether cannot
affect the organ of hearing. The media are radically
different, and cannot be used as substitutes for each
other; and it is therefore wrong to say I hear, unless
what I perceive reaches my consciousness through the
physiological mechanism called the auditory apparatus.
In a figurative sense one may say he hears as he may
say he sees.
“Lo, the poor Indian! whose untutored mind
Sees God in clouds, or hears him in the wind.”
But real seeing and real hearing imply certain
distinct organs adapted to different physical conditions.
MATTER, ETHER, AND MOTION 448
One cannot, by talking, affect one’s eyes; nor will light
waves, as such, affect one’s ears.
Suppose, then, in a s´eance, when a spirit is addressed
thus: Will the spirit please rap upon the table? and
the answer comes at once,—a rap distinctly heard.
The question was an oral one, and was produced by
physical means, regular sound vibrations, and can be
heard by such beings as are possessed of the proper
organs to be acted upon by air vibrations, that is,
ears; and by ears I mean ears, not substitutes of any
sort. What we call speech is absolutely impossible
in a vacuum, as much as is sound, for speech is a
succession of sounds. There are numerous substitutes
for speech,—signs made with the fingers or lips that
do not appeal to the ear; but these are not speech. If,
then, spirits hear, it is because they have ears, organs
that can be affected by sound vibrations in the same
manner as we, the so-called living beings, can be.
Moreover, do not all testify that they can and do both
see and hear?
In like manner one may treat of the sense of feeling,
or any other sense. All imply a molecular structure, a
nervous organization, indeed, everything that goes to
make up a consciousness of the external world such
as is possessed by living beings governed by physical
laws.
IMPLICATIONS OF PHYSICAL PHENOMENA 449
It is clear that what we call pain is immediately due
to disordered nervous structure, and in the absence of
nerves could never be known. This can be tested in
a minute by any one, by simply pricking one’s finger.
Does not the destruction of the nervous tissue in any
manner end the possibility of pain? Can a spirit then
suffer physical pain without a nervous organization?
By pain I mean what all mean by the term, the
sensation which, if severe and long-continued, results
fatally to the sufferer, because the nervous tissue is
itself destroyed.
If some one having read so far, perhaps with
impatience, should say, “All this may be as you say
for living beings, incorporated in a body of flesh
and blood and a nervous system, but we are not to
suppose for a moment that spirits are thus constituted,
and if not, then they are not to be supposed to be
conditioned by such physical laws as all common matter
is conditioned by. They have their own constitution,
different enough from ours, and one cannot reason
from our condition to theirs.” To this I would reply,
that if one cannot do this, if a physicist must not carry
his terms and conceptions into this spiritual domain,
for precisely the same reason the spiritualist must not
talk about a spirit seeing, hearing, feeling, and so on,
unless he admits he is talking loosely, and means by
MATTER, ETHER, AND MOTION 450
those terms only to symbolize his conceptions, and has
to employ such terms as best convey the idea, which
idea cannot be physically true. Even then it is very
difficult to understand why, if the physical terminology
is inappropriate, any one should at a s´eance ask such
a question aloud as, If John be present will he please
rap on the table; for this is sound addressed to an
ear—both of which are purely physical things.
An Arab may not have any difficulty in imagining
a genie that may be summoned by rubbing a cup, to
do wonderful things, and then vanish out of relations
to everything; but no one who has studied deeply into
the significance of physical relations can possibly admit
that affairs in nature go on in such a fast-and-loose
way.
Thus far I have considered such relations of physical
phenomena as have been found by experience to hold
good in the whole range of physics—such relations as
properly come under the domain of what is called law,
and by law I mean mathematical precision, both in the
antecedents and the results. With the exception of the
original apparition of matter and of physical energy,
there has not been found in the whole field of physics,
by any investigator of any nationality, any kind of
a phenomenon which is believed to be unexplainable
on the basis of the knowledge of physical science we
IMPLICATIONS OF PHYSICAL PHENOMENA 451
already possess. Of course, what we call explanation
is merely presenting the antecedent factors of a given
occurrence, both in quality and quantity, and a thing
is fully explained when these are given so fully as to
leave no reasonable doubt as to their sufficiency in the
mind of one who is properly well acquainted with the
data; but the data that enter into a given phenomenon
are the very things most persons know least about;
and a given explanation may be full and adequate,
and yet, to some, seem to be wholly insufficient.
In these days one often hears about specialists—of
their limited knowledge and inadequate preparation for
giving a judgment in other fields than their own. So
it has come to be reckoned that if a man has, by
study and investigation in a given field, made himself
a competent judge, so as to be considered an authority
in that field, he is by so much less fitted to be heard
in the settlement of some question foreign to that
field; whereas some other man who is not known to
have done anything in any field, may be called in
for judgment, to the exclusion of the former, lest his
increased knowledge in some one department should
disqualify him elsewhere.
Do we not hear that biologists are incompetent
judges of mental phenomena, that astronomers are not
competent in biological questions, and so on? If this
MATTER, ETHER, AND MOTION 452
distinction be true to the extent generally assumed, then
philosophy itself is impossible; for if a man’s opinion
can be good only in a small department of knowledge,
and he cannot adequately master more, how shall we
ever know the relationships that constitute philosophy?
The truth is, this is a one-sided affair altogether, and
holds true from but one standpoint. If an astronomer
propounds a chemical theory of the sun, will it be
needful in any degree that the chemist who reviews
the work shall have even studied astronomy or paid
the slightest attention to telescopes or solar affairs? If
chemical science is involved, it is for the chemist to
say whether what is propounded is adequate or not.
That is to say, the man who concerns himself with the
constitution of the sun must so far be a chemist, but
a man may be a chemist and never concern himself
about the sun.
Again, if a biologist who is admittedly ignorant of
chemical and physical science makes statements that
plainly contradict the laws of energy as determined in
chemistry and physics, and if a physicist challenges
the statements, shall the latter be silenced by calling
him a specialist who may be competent enough in his
own field, but who knows nothing of biology? Or
shall he be told that physical laws may be rigorous
enough in one mass of matter, but not in another? Is
IMPLICATIONS OF PHYSICAL PHENOMENA 453
it to be believed that physical laws thus play fast and
loose? Here the arithmetic holds good, but there all
is indefinite, and would not this be a fine example of
dictation out of one’s field? Physiologists tell us that
ultimately every physiological problem reduces itself
to one of chemistry and physics.1 If this be so, is it
not plain that the one who treats broadly of biological
problems must either be a physicist or submit his work
to the criticism of a physicist? But a man may be
a physicist and never trouble himself about biological
questions.
If a social philosopher presents a scheme for
ameliorating the evils present in society, in which scheme
he plainly ignores the laws of life as determined by
biologists,—as if such laws were not the very determining
factors which must first be reckoned with,—shall not
the biologist condemn such work? and shall he, too,
be told that however much he knows of biology, he is
incompetent in sociology? Plainly, not so. But is this
process a reversible one? Can the sociologist criticise
the biologist’s work unless he be himself a biologist,
or the biologist criticise the chemist’s or physicist’s
work unless he be so far a chemist or physicist? He
certainly cannot; and this shows that there is a certain
1See Appendix, p. 477.
MATTER, ETHER, AND MOTION 454
relationship among these subjects in which there is an
order of dependence. In order to fully understand
and explain a sociological problem, a knowledge of
psychology is essential; a working knowledge of biology,
or the laws of life, and no adequate knowledge of this
can be had without a preparation in chemistry and
physics.
In this there is nothing new, but it is generally
ignored by most persons who treat on broad questions.
It is plain that every kind of a question is, in the last
analysis, referable to the laws of physical phenomena,
and from these there is no appeal. There are not many
who like this, it is true; but the test for truth is not
what one likes or dislikes, but whether the proposition
is in accordance with the best and most fundamental
knowledge we have. Some of those fundamental
truths discovered within the past fifty years, and not
questioned by any one who can stand an examination
on them, were given on page 427; and whoever sees,
or thinks he sees, a phenomenon which he interprets
in a way which plainly contradicts or ignores those
laws, does not so much have a contention with any
man as with science itself. If those laws are not
irrefragably true, then we have no science at all, no
philosophy, knowledge is scrappy, and what we call
the interdependence of phenomena is a myth.
IMPLICATIONS OF PHYSICAL PHENOMENA 455
Some of the phenomena alleged to happen at spiritual
s´eances, such as levitation of human bodies, writing
between closed slates, the moving of matter without
contact, and so forth, are said to be as thoroughly
proved as any of the facts of the fundamental knowledge
I have treated. Such a statement cannot have come
from any one who knows how the knowledge I spoke
of was obtained, or how it may be verified by anybody
who cares to take the pains. None of it depends in any
degree upon anybody’s dictum. If any one has doubts
as to the constitution of water, he can determine it
himself in half a dozen different ways. If he doubts
that the earth is eight thousand miles in diameter, he
can measure it in several ways. If he thinks a pound of
coal does not have eleven million foot-pounds of energy,
he can himself try it and be satisfied. Any one can
satisfy himself by himself; assistance of others is only
a convenience, not a necessity, and the fundamental
statements are now believed by so many because so
many have tested them, and all have reached the same
conclusion. Furthermore, great commercial enterprises
are founded upon some of them, as when so much
limestone and coal are mixed with a given ore of iron
for its reduction. So if such alleged facts be true, it
cannot be true they are as thoroughly proved as the
ones I stated, and they will not be so proved until
MATTER, ETHER, AND MOTION 456
each one can be verified in like manner.
There is another excellent reason for denying that
they are proved in any scientific sense. All physical
phenomena, so far as they have become a part of physical
science, have been examined and reported upon by
physicists; and both phenomena and their interpretation
have been the subject of remorseless criticism, and have
been adopted, if at all, on compulsion; their acceptance
has been a matter of last resort. This is true in all
departments. Why should one believe that the world
turns round unless there is no other possible way to
explain and account for all the facts which must be
reckoned with in any explanation? The theory itself
is so remote from the common experience of mankind
that nobody suspected it for thousands of years, and it
is not at all obvious to one who is not acquainted with
phenomena out of the range of ordinary experience.
The form of the earth, the aberration of light, the
apparent change of latitude, and so forth, have to be
considered even more than the recurrence of day and
night. For most of the purposes of life it does not
matter whether it turns round or not, and most men
have no interest in the question further than that it
accords or not with their other beliefs and feelings.
But the answer to the question, “Does it turn?” is
not one that can be settled by submitting it to the
IMPLICATIONS OF PHYSICAL PHENOMENA 457
vote of the world. The judgment of one Galileo is
worth more than that of all the rest of the world
on that point. Once admit that no department of
science is independent of other departments, and that
no phenomenon occurs independent of relations which
must be satisfied by any attempted explanation, and
it follows that no explanation of an event should be
adopted and be considered a part of science, unless
it is shown to be in agreement with what is known.
Hence, if an event is reported which appears to be out
of relation with those established relations which there
is general agreement upon, there is the best of reasons
for thinking that either the event did not happen, or
that it did not happen as reported, especially if the
one reporting it is unacquainted with the variety of
ways in which it is possible to do the same thing.
If one sees a wheel turning round but does not see
its connections, how can he tell whether it is turned
by muscular action or water-power or wind-power or
gravity or heat or electricity or magnetism, every one of
which is capable of turning a wheel? Even if he can see
the connections, he cannot always tell what makes the
wheel go without further investigation. Air and steam
will make a water motor go as well as water itself, and
the presence of electrical devices would not insure that
the wheel was turned by electricity, and the absence
MATTER, ETHER, AND MOTION 458
of such electrical devices would not insure that it was
not driven by electrical agency. Hence the testimony
of witnesses only, even though they were otherwise
competent, would be of little weight in deciding what
made the wheel go. If the question were one of any
importance it could be determined only by a competent
investigator with proper appliances, and unhindered by
restrictions of any sort. One cannot trust his sense of
sight implicitly. Many persons have lost fingers because
the buzz saw looked as if it was still; and it is easy
with the zoetrope, and in other ways, to produce the
impression of movements that are not taking place; so
it might be that after all the wheel was not turning,
or even that there was no wheel at all.
Admitting, for the argument’s sake, that the alleged
phenomena at s´eances are real occurrences and must
be accounted for, there are certainly three different
possible ways:—
1. By more or less skilfully devised tricks, and
fraudulent only in the attempt to make others believe
they are not tricks. To be certain they are not the
results of manipulative skill on the part of some one,
only a skilful juggler might be able to find out. It is
known that hundreds have been thus imposed upon;
and skilful jugglers, such as Hermann and Maskaline,
who have investigated many such, declare themselves
IMPLICATIONS OF PHYSICAL PHENOMENA 459
satisfied that the whole of it is trickery.
2. Suppose some of the surprising things done
are not the results of conscious duplicity, then it
may be, as most interested persons contend, the work
of disembodied spirits who, through the agency of
mediums, do apparently the most absurd and irrational
things, but are never willing or able to do the simplest
reasonable thing to satisfy a competent judge; who
mutter no end of maudlin rubbish, add nothing of
wisdom or knowledge to mankind, and justify Professor
Huxley in saying that if such is the state of the dead
we have another good reason against suicide.
3. There are a small number who think some of
the phenomena to be genuine, but who attribute them
not to spirits, but to some obscure physical force not
yet understood, and but little investigated. This is
the attitude of Professor Crookes, and of the Milan
experimenters.
As to the class that is satisfied with the spiritistic
interpretation, it may be remarked that such an
explanation is in accordance with the attempts of the
race to give a rational explanation of all kinds of
phenomena. In the absence of proper knowledge, what
seems simpler or more natural than to assume some
intelligent agency as the cause of any obscure event?
This it was that peopled the mountains, glens, trees,
MATTER, ETHER, AND MOTION 460
and rivers with unseen beings, watchful and interested
in the affairs of men. The more ignorant, the closer
was the fetich; the more enlightened, the higher these
agencies retreated into the sky, useful now chiefly for
literary and artistic purposes. For some reason it has
always been discreditable to be without some theory
for all sorts of occurrences, and even to-day, in the
most enlightened communities, a man is liable to be
denounced for his stupidity or his cowardice if he
says, about some matters, I don’t know. It is said,
however, that some of the phenomena at s´eances bear
the marks of intelligence such as do not belong to
natural occurrences, and that it is a fair inference that
other minds than the witnesses are present. When
Kepler discovered that the planets moved in elliptical
orbits instead of circular ones as had been supposed, he
felt bound to give some reasonable explanation of the
facts. He knew of nothing but intelligence that could
maintain such motions, and he therefore supposed that
each planet must have some guiding spirit. When the
law of gravitation was applied, it was found that a
circular orbit was the only unstable orbit in the system,
and that gravity alone was sufficient to account for the
order, the harmony, and all the variety of motions; so
the spirits were dismissed from further duty. When a
spider has a leg grow to replace one that has been lost,
IMPLICATIONS OF PHYSICAL PHENOMENA 461
it has been held to be due to intelligent action superior
to ordinary chemical and physical action. When a
crystal of quartz is seen to replace a part accidentally
lost, so as to complete its symmetry before it begins to
grow elsewhere, it appears as if mind was at work here
quite as much as in the other case, only in the latter
most persons are content not to follow the implications,
for they quickly see the philosophical rocks ahead. The
real truth is that the further one pursues the causes of
phenomena the more clearly does it appear unlikely
that disembodied intelligence is behind any particular
phenomena.
Among all those who make up the great class
of believers in the spiritualistic theory of physical
phenomena, there is not a single physicist; that is, not
one to whom one would go for an explanation of any
complicated physical process. It is assumed that he is
no better qualified to investigate s´eance phenomena than
others who do not know what to expect and look out
for in simpler cases, and that he is unreasonable if he
does not accept the statements of untrained observers
as being as good as his own observations.
It is true that he has some prepossessions. He does
not believe the multiplication table should be trifled
with. He knows that most things may be done in many
different ways, independent of appearances. He knows
MATTER, ETHER, AND MOTION 462
a man may sometimes not perceive what is plainly
before his eyes, simply because he was not looking
for it. He deems it right to exhaust the possibilities
of the known before summoning some unknown and
hypothetical factors in any given case. He knows it to
be well-nigh impossible for a man to give an entirely
accurate account to-day of what occurred yesterday. He
knows that a photograph is a better witness of an event,
and that a stenographic report of statements made is
more reliable than any man’s memory. He knows that
the interpretations of events by mankind have never
been true interpretations, and that the general beliefs
of mankind have never been confirmed by science in
any particular, and that, so far as anything has been
settled, it has been decided against the opinions and
judgment of mankind and its leaders. He is aware
that his key has unlocked every one of the doors in
Doubting Castle that have been unlocked, and therefore
he believes that the implications of physical science as a
whole are against any generally received interpretation
of any event that has not been subjected to its scrutiny.
PHYSICAL AND PSYCHICAL PHENOMENA 463
CHAPTER XVI
The Relations of Physical and Psychical Phenomena1
Knowledge has grown apace within the past fifty
years. It is generally admitted that more has been
acquired in this time than in all the preceding centuries.
Furthermore, the knowledge thus acquired has not
been simply an addition to the mental possessions of
former days; it has instead been of such a kind as
to completely overthrow nearly all former notions of
nature and its mode of operations, and the new product
can hardly be allowed to be an outcome of the work
of earlier men. It is in the nature of a catastrophe
where old continents have sunk and new ones have
arisen from old ocean beds.
This generation lives in a new world, with new
environments, new ideas, new explanations, new
philosophy, new ideals, and new beliefs. We have
new astronomy, new chemistry, new physics, new
psychology, new natural history, and everybody is on
the qui vive to know what can possibly come next.
1Read before the Psychical Congress, Chicago, August, 1893.
MATTER, ETHER, AND MOTION 464
This does not mean that nature goes on in a different
way from what it had hitherto done, but that we have
mentally grasped a new and transforming idea. We
have reached an elevation from which it is possible to
survey a broader field, and can interpret phenomena
better because their relations are better perceived, and
because of this it is seen that the old interpretations
were all wrong, and, indeed, were worthless, because
not true. While all this is granted readily by most
thoughtful persons, there are not a few who recognize
the changed opinions in the various sciences and
philosophy in general, who are not at all persuaded
but what the present philosophy of things, which is
dubbed evolution, is only a passing phase and may
itself presently give way to some new and possibly
truer conceptions, being content to be mildly agnostic
on such matters, and willing to wait with patience
for more light. There are some who think the new
philosophy does not take account of all the known
factors, if, by chance, there may not be unknown factors
of as much or more importance than any which have
been included, and which a final philosophy of things
will certainly include; and such object strenuously to
the limitations which the current philosophy seems to
set to knowledge and to the ideals of the race.
The man of science hears rumors of phenomena
PHYSICAL AND PSYCHICAL PHENOMENA 465
which are said to be as certain as any in his own field,
which he has never investigated, and which cannot
come into his category of related things. Some of these
reported happenings are as marvellous as any miracles
that have been recorded. Persons of undoubted probity
have reported phenomena taking place in their presence
which, if true, give credence to many things for which
in the past men and women have been burned to death
as wizards and witches. Thus, I have an acquaintance,
an eminent man not given to romancing, who assures
me he has seen, in undimmed light, a chair ten feet
from any person rise as if some one had hold of
its back and come and set itself down by his side.
Something of the same kind is said to have taken
place in the Milan experiments of last fall. Mr. William
Crookes tells us that the weight of a body has been
changed to be more or less according to an effort of
the will of Mr. Home, and likewise in Milan the weight
of the medium varied as much as fifty pounds.
Now, there have been numerous attempts to define
a miracle for the purposes of philosophy, and usually
it is not the thing accomplished so much as the means
adopted for doing it. The antecedents of the event are
supposed to be other than the usual ones which might
do the same thing. Thus, a chair may be moved by a
person who lifts it and carries it to a new place; but
MATTER, ETHER, AND MOTION 466
the chair may be pushed by a stick or pulled by a
string to a new place, while no one touched it, and all
who have been to see Hermann, and other magicians,
have seen things move about in a surprising manner
when no one touched them. In such cases it is believed
that none but well-known means are skilfully used to
produce such displacements, and that any one might
learn the art if it were worth his while. In other
words, no one thinks he is looking at a miraculous
event at a magician’s show, no matter how surprising
the thing done; but if any person should be able
to make a chair, or an object, move from one place
to another without the mechanical adjuncts of some
sort which are needed by others, by an act of will
rather than by the employment of what we call energy,
such a person is able to work what has always been
called a “miracle.” His method of doing that thing
is a super-natural method, which is not the gift of
every one even in the slightest degree; for any one
can try and satisfy himself as to whether he can, by
any simple act of will, make the tiniest mote in a
sunbeam or the most delicately poised needle move in
the slightest degree. This is the common experience;
and because it has been found by experience that
matter never moves except when some other body has
previously acted upon it with a push or a pull, it has
PHYSICAL AND PSYCHICAL PHENOMENA 467
come about that we have reduced the experience to the
statements embodied in so-called laws of motion, have
found them to be justified and without any exception
so far as investigation has gone, and this, too, by
a multitude of persons for two hundred years. As
modern science rests upon a mechanical basis, as it is
concerned altogether with the phenomena of matter and
the relations of the phenomena, and as these have been
found in every case that has been fully investigated to
conform to mathematical laws rigorously, not partly or
dubiously, is it not much more probable that any other
phenomenon, no matter what, that involves matter and
its changes, does conform strictly to the general laws,
than that these laws are sometimes inoperative?
Probably the whole thing resolves itself into this:
Are the fundamental properties of matter variable?
Some of the phenomena alleged to happen at s´eances
imply that they are. How strong the case is against
such assumption, I think is not perceived by many
persons who give credence to the happenings, but who
are not well equipped with physical knowledge. Many
persons seem willing enough to admit physical laws
and physical processes in what they take to be the field
of physics, but they hold that there are other fields
just as certain, and among such, mind, that controls
matter and its forces, and to which it is not necessarily
MATTER, ETHER, AND MOTION 468
subject; that it is perfectly philosophical to think that
mind may exist independent of matter and its relations,
and be able in this condition to control phenomena.
Let us examine this. Assume that every physical
process in the world should be suddenly stopped, so
there should be no change. That would mean that
all motions were stopped. There would at once be
neither day nor night, for these are due to the earth’s
rotation; no light, for light is a wave motion; there
would be no heat, for heat is a vibratory motion;
there would be no chemical changes, for they depend
upon heat; there would be neither solid nor liquid nor
gas, for each depends upon conditions of temperature,
that is, of heat, which is assumed to be absent; there
would be no sight, for that implies wave motions;
nor sound, for that implies air waves; nor taste, for
that implies chemical action; nor smell, for like reason;
nor touch, for that implies pressure—the result of
motion. The heart would cease to beat, the blood
to flow, and consciousness would be stopped. Every
one of the senses would be obliterated or annihilated;
nothing would happen, because there would be no
change anywhere. Every phenomenon in the world of
sensation would be stopped, because every phenomenon
in the physical world had stopped; which is the same
as saying that all we call sensations are absolutely
PHYSICAL AND PSYCHICAL PHENOMENA 469
dependent upon physical changes, going on all the time
independent of our will or choice, and which cannot
be controlled in the slightest degree by anybody. Every
phenomenon of every kind, then, consists in, as well as
is dependent upon, matter and its motion, and there
is in the whole range of experience no example of any
kind of a phenomenon where matter, ordinary matter,
is not the conditioning factor. There is no known case
where force or energy is changed in degree or direction
or kind but through the agency of matter. Every kind
of a change implies matter that has thus acted. What
is called the correlation of forces means that one kind
is convertible into some other kind of energy, as heat
into mechanical energy in the steam engine. But the
engine, a material structure, is essential for the change.
What is called the conservation of energy means that
in all the exchanges energy may undergo, as heat into
light, or work of any kind, the quantity of it does not
vary. The matter, as such, does not add to, or subtract
from it; hence only a material body can possess energy,
and a second material structure is necessary in order
that the energy of the first should be changed into any
other form. So it appears there must be at least two
bodies before anything can possibly happen.
This all means that what we call energy is embodied
only in matter, and that what we call phenomena
MATTER, ETHER, AND MOTION 470
is but the exchange of energy between different
masses of matter; also that these exchanges take place
with mathematical precision, else prediction would be
impossible, and computation a waste of time.
Now, assume that the physical structure of an
individual was kept intact, and that every atom and
molecule in the body maintained its relative position
after all motions had ceased. Assume, too, that the
mind or soul, or whatever one chooses to call the
conscious individuality, was present and capable as
ever of acting upon the material structure; can a single
atom be moved in the slightest degree? If any be
moved, then energy has been expended, energy which
must have existed elsewhere or have been created
de novo. For conscious perception, whether sight or
sound or any other, motions embodying energy are
essential, as pointed out; and hence, to produce any
perception, some motions would necessarily have to be
initiated, and to initiate them energy from some source
must be supplied. All the energy the matter had has
been destroyed according to the assumption; so, if
any movement has begun, it must have been created
or produced from some other unthinkable condition
which was not energy, in some such sense as matter
is supposed to have been created, in which something
is made out of nothing. The demand is for creative
PHYSICAL AND PSYCHICAL PHENOMENA 471
power. Admit for the argument’s sake that it is done,
and matter begins to move in any kind of a way; so
far it possesses energy, physical energy as embodied
in matter. Call the amount of it “A.” Now, if the
original condition of things was established, so far as
the amount of energy was concerned, which may be
called “B,” then the whole amount of energy is “A
plus B.” It will make no difference in this sum if one
supposes that the original motions and energy were
not interrupted; for if, on account of mind action,
any particle moves more or less than it would have
done with its original supply, then something has been
added to the store of energy in matter, and what is
called the conservation of energy is not true.
Until all phenomena have been examined, there will
be obscure happenings and things to be explained by
some one who can; but it is no final explanation of
anything to say, “A man did it,” or “An intelligence
did it.” What kind of changes, that is, what kind of
phenomena, the forms of energy we are now acquainted
with are capable of producing no one can now limit,
certainly not one who has not been to the pains to
understand how the simple ones take place. I have
often been told that things cannot move in certain ways,
or certain things cannot be done except by intelligent
action or guidance; but it may be remembered that
MATTER, ETHER, AND MOTION 472
Kepler thought guiding spirits were needful for making
the planets move in their elliptical orbits. If one must
explain an obscure phenomenon, is it not wisest to
explain it in accordance with what we know rather
than in accordance with what we do not know? It
is better for one to acknowledge his ignorance of the
cause of it, than to go romancing for a reason, and
repudiate all we really do know and its implications. A
juggler may do the most surprising things before one’s
eyes, but if one cares to inquire into the antecedents
of anything done he will have no difficulty in tracing
it as far as the breakfast. What is meant is, the juggler
does nothing which does not require energy,—energy
of the ordinary sort, in the same sense as if it had
been required for sawing wood or walking up the
street. As for consciousness, dexterity, and all that
is implied in both, I pointed out a little way back
there could be neither in the absence of those changes
which constitute physical phenomena; and that not
only life itself, but consciousness as we know it, would
be impossible without the exchanges in the energy
embodied in the cellular structure of the brain. In the
light of what has been accomplished in the direction of
physiological psychology, it is entirely unwarrantable to
assume that even thinking can go on in the absence of
physical changes of measurable magnitude; and this is
PHYSICAL AND PSYCHICAL PHENOMENA 473
the same as saying that what we call intelligent action
is physical at its basis.
There is such a formal agreement as well as actual
connection between conscious life and the life of the
brain, that it is not to be supposed any one who
has properly attended to the facts will venture to
deny them. Argue as one will, it is true there is no
experimental knowledge that is a part of science, of
consciousness separable from a material structure called
brain, in which physiological changes take place as the
conditions for thinking as well as for acting. This is the
only known relation of mind and body. However this
association of such apparently different provinces is to
be explained, it is still true that for every phenomenon
in consciousness there is a corresponding phenomenon
in matter. Psychologists have pointed out that the
phenomena indicate an identity at bottom between
the activity of consciousness and cerebral activity. To
follow this out into particulars would be interesting
and perhaps profitable to most; but the significance
of it here is that even in the psychological field,
where the opportunities for investigation are right at
hand and most is known, there is no evidence for
consciousness apart from a material structure, or that
the law of conservation of energy does not hold as
strictly true here as elsewhere in physics. So there
MATTER, ETHER, AND MOTION 474
is no experimental reason for assuming the existence
of incorporeal intelligences. There is no psychological
question that is not at the same time a physiological
question.
Experimentally it appears that the association of mind
with matter and energy is not of such a nature that one
is at liberty to assume their dissociation, any more than
one is at liberty to assume gravitation or magnetism
as independent existing somethings controlling matter
according to certain laws. So any hypothesis invented
to account for an occurrence that is not yet explained
ought not to be in contradiction to everything else we
know, and ought not to be entertained except as a last
resort; and the hypothesis of disembodied intelligences
acting now in and now out of the field of material
things is such an one. If such phenomena really happen
at s´eances as are alleged, then we have to do with
affairs strictly within the line of physics, whether such
phenomena are so-called mental or so-called physical.
It is useless to affirm that the two are such radically
different phenomena that the methods of the latter
are not appropriate in the former; and the extensive
laboratories for physiological psychology, which are
now being established in all the larger institutions of
learning, is a sufficient denial of the proposition.
The term psychics is intended to denote something
PHYSICAL AND PSYCHICAL PHENOMENA 475
different from the phenomena of psychology as manifested
in a given organism. It is supposed to relate to
the sympathetic relation of one mind to that of another
quite apart from the ordinary physical relations, that is,
from the senses. As for the mind-reading as exhibited
some years ago by Brown and others, I believe it is
now agreed that it is due to the sense of touch, and
cannot be done without contact. In hypnotic work
there has to be “suggestion,” and most of the very
remarkable cases, such as those in France last winter,
have been shown to be gross frauds. But let it be
granted that some of it is genuine, that it is possible
in some cases to impart information and discover the
thoughts of another without the common resources, it
does not then follow that the method is extra-physical.
If only here and there is to be found an individual
called a psychic, who is thus sensitive, and it is not
a race endowment, one no more need to summon a
mysterious supernormal agency to account for it, than
such is needed for the work of Newton or Mozart.
Because a phenomenon has not been explained, and
no one knows how to explain it, is no reason at
all for supposing there is anything mysterious about
it. There are any number of phenomena throughout
nature that have not been explained, and no one knows
how to explain on the basis of what is known. Such,
MATTER, ETHER, AND MOTION 476
for instance, is the whirlwind that crosses the field,
raising dust and leaves into the air. No one has
explained the soaring of birds, no one knows what
goes on in an active nerve, or why atoms are selective
in their associates. Ignorance is not a proper basis
for speculation; and if one must have a theory, let it
be one having some obvious continuity with our best
physical knowledge.
What is here given is not intended to be a denial
that such phenomena as thought-transference, or even
the most surprising things such as those described in
the Milan experiments, take place. It is only intended
to emphasize the probability that whatever happens
has a physical basis, and is therefore explained only
when these physical relations are known.
APPENDIX
Note to Page 67.
As to whether it is considered as known that the
sum of the interior angles of a plane triangle are exactly
equal to one hundred and eighty degrees: “Suppose
that three points are taken in space, distant from one
another as far as the sun is from a Centauri; and that
the shortest distance between these points is drawn so
as to form a triangle. And suppose the angles of this
triangle to be very accurately measured and added
together; this can at present be done so accurately that
the error shall certainly be less than one minute, less
therefore than the five-thousandth part of a right angle.
Then I do not know that this sum would differ at all
from two right angles; but I also do not know that the
difference would be less than ten degrees, and I have reasons
for not knowing.”
W. K. Clifford: Aims and Instruments of Scientific Thought.
“If the Euclidian assumptions are true, the constitution
of parts of space at an infinite distance is as well
known as the geometry of any portion of this room.
477
APPENDIX 478
So that here we have real knowledge of something at
least that concerns the cosmos; something that is true
throughout the immensities and the eternities. That
something Lobotchewski and his successors have taken
away.”
W. K. Clifford: Philosophy of the Pure Sciences.
“In this case the universe as known becomes a
valid conception, for the extent of space is a finite
number of cubic miles. If you were to start in any
direction whatever, and move in a perfectly straight line
according to the definition of Liebnitz, after travelling a
most prodigious distance . . . you would arrive at—this
place.”
Ibid.
“It must remain an open question whether, if we
had large enough triangles, the sum of the three angles
would still be two right angles.”
Enc. Brit. 9th ed., Art. Measurement.
“It is true that according to the axioms of geometry,
the sum of the three angles of a triangle are precisely
one hundred and eighty degrees; but these axioms are
now exploded, and geometers confess that they, as
geometers, know not the slightest reason for supposing
them to be precisely true. That they are exactly that
amount is what nobody can be justified in concluding.”
APPENDIX 479
C. S. Peirce: Monist, vol. i. No. 2, p. 174.
“All that we need do is to call the attention of
those who busy themselves with mental philosophy to
this generalization of geometry as one of the results
of modern mathematical research which they cannot
afford to overlook.”
George Chrystal, in Enc. Brit., Art. Parallels.
Such as care to look into the matter further will find
the subject treated in an untechnical way in the works
of W. K. Clifford, in the chapters on the “Theories of the
Physical Forces,” “Aims and Instruments of Scientific
Thought,” and especially the “Philosophy of the Pure
Sciences.” There is much on it in the American Journal
of Mathematics, vols. ı. and ii., also in the “Proceedings
of the Royal Society,” Edinburgh, vol. x., 1879, and in
article “Measurement,” Enc. Brit.
Note to Page 249.
In 1881 the author discovered how electric ether
waves could be produced and identified, where the
vibratory rates were as high as 4000 or more per second,
by employing static telephones detached and removed
many feet from the inducing electric current. These
gave a wave length of 186000
4000 = 46+ miles long. Hertz,
Tesla, and others have since then described methods of
APPENDIX 480
producing them so short as to be but a few feet long.
When they have thus been mechanically shortened so
as to be but the one forty-thousandth of an inch in
length, they will be seen by the eye as red light.
Note to Page 291.
See Maxwell’s “Theory of Heat,” pp. 160, 161.
H
S
= h
T
. S and T are the absolute temperatures of
the hot and cold bodies in Carnot’s engine.
H and h are the quantities of heat taken up and given
out. When T = 0, h = 0, when h is the equivalent of
the work done. As this is 0 at absolute zero, no work
could be done in changing the volume of a substance at
that temperature. There can be no cohesion among the
molecules or atoms, for this would require that work
should be done to separate them. It is the temperature
of dissociation.
This conclusion is one to which chemists and
physicists have been led by their researches. For
example, Dr. Lothar Meyer says, “At the lowest
temperature to which we can attain, the majority of
chemical reactions studied under these conditions have
been found to cease or to proceed very slowly, so
that it would appear to be very probable that at the
absolute zero, viz., 273, a temperature much below
APPENDIX 481
the lowest yet attained, chemical action would cease
altogether from the absence of any form of heat motion
whatsoever; so without heat there would be no exertion
of the so-called chemical affinity.”
Modern Theories of Chemistry, § 211.
Note to Page 336.
The hypothesis of a “vital principle” is now as
completely discarded as the hypothesis of phlogiston
in chemistry. No biologist with a reputation to lose
would for a moment think of defending it.
John Fiske: Cosmic Philosophy, vol. i. p. 422.
“We can demonstrate the infinitely manifold and
complicated physical and chemical properties of the
albuminous bodies to be the real cause of organic or
vital phenomena.”
Haeckel: History of Creation, vol. i. p. 330.
“The aim of modern physiology is to conceive all
organic processes as physical or chemical.”
H¨ offding: Outlines of Psychology, p. 57.
“Physiologists must expect to meet with an unconditional
conformity to law of the forces of nature in
their inquiries respecting the vital processes. They will
have to apply themselves to the investigation of the
APPENDIX 482
physical and chemical processes going on within the
organism.”
Helmholtz: Scientific Lectures, p. 384.
“A vital element, i.e., an element peculiar to
organisms, no more exists than does a vital force working
independently of natural and material processes.”
Claus & Sedgwick: Zo¨ology, part i. p. 10.
“In Physiology the word life is understood to mean
the chemical and physical activities of the parts of
which the organism consists.”
B. Sanderson: Nature, vol. xlviii., p. 613.
“Modern physiology interprets the phenomena of
organic life by means of physical and chemical laws.
An appeal to ‘vital force’ or to the intervention of
mind, it does not recognize as an explanation of an
organic phenomenon.”
H¨ offding: Outlines of Psychology, p. 10.
“Physiology thus appears as a branch of applied
physics, its problems being a reduction of vital
phenomena to general physical laws and thus ultimately
to the fundamental laws of mechanics.”
Wundt: Lehrbuch der Physiologie, p. 2.
“It must not be supposed that the differences between
living and not living matter are such as to justify the
APPENDIX 483
assumption that the forces at work in the one are
different from those to be met with in the other.”
Huxley: Art. Biology, Enc. Brit., p. 681.
“Zo¨ology, the science which seeks to arrange and
discuss the phenomena of animal life and form as the
outcome of the operation of the laws of physics and
chemistry.”
Lankester: Art. Zo¨ology, Enc. Brit., p. 803.
“If corporal functions are mediated by immaterial
agencies, physiological science is impossible.”
G. Stanley Hall: Amer. Jour. Psychology, vol. iii. p. 74.
“It has not occurred to me that any one now uses
the term ‘vital force’ in any other way than as a
convenient method of expressing the sum total of the
physical and chemical activities of organisms.”
Prof. E. L. Mark, Harvard University.
“These phenomena of life, though they may not as
yet be physically and chemically explained, are certainly
not to be referred to the working of any special vital
force peculiar to organisms. . . . We have to do here
with the same forces and the same substances that we
meet with elsewhere in nature.”
Lang: Textbook of Comp. Anat., London, 1891, p. 2.
“Modern science has allowed the vitalistic theory
APPENDIX 484
(vitalismus) to drop; instead of by means of a special
vital force, it explains irritability as a very complex
chemico-physical phenomenon. It is only distinguished
from other chemico-physical phenomena of inorganic
nature by degree, namely, that the external stimuli come
in contact with a substance of complicated structure,
an organism, and correspondingly produce in it also a
series of complicated processes.”
O. Hertwig: Die Zelle und die Gewebe, p. 75, 1893.
“I know of no authority in recent years which
recognizes a distinct vital force; all students of nature,
so far as I am aware, explain all the phenomena of
life by means of physical and chemical forces.”
Prof. J. S. Kingsley, Tufts College.
INDEX
Absolute zero, 291, 403
Action at a distance, 104
Affinity, chemical, 288
Albumen, size of molecule, 18
Amp`ere turns, 251
Arc light, 260
Arcturus, 173
Atmosphere, height of, 30
Atoms, 12, 21, 22
Atoms, as vortex rings, 418
Atoms, chemical properties, 287
Atoms, life associated with, 29,
356
Atoms, unalterable, 25, 26
Atoms, vibrations of, 292
Attraction depends upon
distance, 101
Attraction of disks, 112
Attraction of vibrating fork, 103
Attraction of vortex rings, 113,
293
Attraction, gravitative, 99, 371
Blavatsky, Madam, pretensions
of, 430
Boiling-point pressure, 149
Bonnenburger’s apparatus, 46
Camera, 194, 195
Catalysis, 300
Cause and effect, 90
Cell structure, 337
Charles, Law of, 403
Chemical effects, 262
Chemical field, 296, 366
Chemical origin of electricity, 211
Chemical reactions depend on
temperature, 403
Chemism, 286
Chemism and heat, 289, 403
Cohesion, destroyed, 400
Cohesion, in solids and liquids,
399
Color, nature of, 406
Color-blindness, 204
Colors, 197
Combustion, 123
Conductivity, electrical, 227, 230
Consciousness implies energy,
466
Corn, life of, 350
Corti’s fibres, 330
Crookes’ tubes, 269
Crystallization, 295, 298, 367
485
INDEX 486
Decomposition of water, 263
Density, 8
Diamond, hardness of, 405
Dispersion, 165
Dissociations, 156, 263
Dynamo, 256
Ear, 329
Earth, a magnet, 364
Earth, curvature, 82
Earth, diameter of, 65
Earth, solidity of, 150
Earth, velocity of, in space, 39
Echo, 318
Efficiency of machines, 255
Egg, 350
Elasticity, 409
Elasticity due to motion, 45, 409
Electric lamps, 258
Electrical antecedents, 223
Electrical effects, 277
Electrical effects, reversible, 279
Electrical field, 235, 360
Electrical stress, 236
Electrical waves, 237, 364
Electricity, activity, 232
Electricity, dual, 281
Electricity, electrical origin, 218,
276
Electricity, magnetic origin, 216
Electricity, mechanical origin,
215, 276
Electricity, origin of, 208, 275, 424
Electricity, thermal, 208
Electro-magnets, 96, 252
Elements, 162
Energy in the ether, 93, 125
Energy of rotation, 80
Energy of translation, 75
Energy of vibration, 78
Energy, factors of, 83, 91
Energy. What determines
transfer, 257
Ether, 30, 37, 39, 95
Ether phenomena not explained,
422
Ether pressure, 245
Ether rotations, 281
Ether wave qualities, 160
Ether waves, 160
Ether waves, their source, 161,
248
Ether, a non-conductor, 229
Explosion products, 84
Fable, La Fontaine’s, 428
Falling bodies, 71
Falling bodies, energy of, 71
Fibres of Corti, 330
Fields, chemical, 296, 366
Fields, electrical, 235, 360
Fields, magnetic, 242, 257, 302
INDEX 487
Fields, mechanical, 296
Fields, physical, 358
Fields, thermal, 358
Flames, 164
Food, 341
Foot-pound, 71, 73
Force, vital, 336
Foster, Dr. Michael, quoted, 356
Friction, its effects, 27, 39
Fuels, 122
Galvanic battery, 213
Gas, destroyed, 403
Gas, free path in, 401
Gas, motion in, 400
Gas, pressure in, 401, 403
Gaseous absorption, 170
Geissler’s tubes, 268
Geometry, 67, 68
Goose, work in flying, 77
Gravitation, 97, 107, 371, 416
Gravitation, law of, 100
Gravity follows from structure,
417
Gravity, specific, 8
Growth, 300, 351, 372
Growth of crystals, 340, 456
Growth of lobster, 340
Gunpowder, 123
Guppy, Mrs., 430
Gyroscope, 414
Hair-cloth loom, 375
Hardness not atomic property,
405
Hearing, what is implied in, 443
Heat by impact, 269
Heat of the sun, origin of, 142
Heat unit, 134
Heat, chemical origin of, 121
Heat, effects, 147, 305, 402
Heat, electrical origin of, 124
Heat, mechanical equivalent, 131
Heat, mechanical origin of, 118
Heat, nature of, 137, 141
Heat, radiational origin of, 125
Helmholtz, 41
Hertz waves, 412, 421
Hydrogen vibrations, 138
Hypothesis, gravitation, 107
Hypothesis, needful, 112
Immortality, 29, 439
Impenetrability, 408
Induction coils, 250
Inductive action, 219, 233, 300,
363
Inertia, 84, 413
Joule, 132
Jupiter, temperature of, 172
INDEX 488
Kepler, the guesser, 107
Kinematics, 54
Kinetics, 54
Knowledge, rapid growth of, 460
Law, physical, 446
Laws not compulsory, 423
Lever, 381
Life, 332
Life, definitions of, 334
Light waves, 248
Light, a sensation, 161, 434
Light, energy of, 95
Light, its nature, 31, 95, 160, 436
Light, its velocity, 30, 32
Lighting, electric, 257, 266
Lightning, 222, 268
Luminous effects, 267
Machines, 375, 391
Magnet, electro, 96
Magnetic field, 242, 245, 257,
302, 364
Magnetic induction, 249
Magnetic rotation, 282
Magnetic waves, 96, 243, 248, 412
Mars, atmosphere of, 172
Mars, signalling to, 260
Mass, 413
Materialists, 421
Materializations and energy, 437
Mathematics, 106
Matter, as modes of motion, 398
Matter, characteristic property, 4
Matter, divisibility of, 10
Matter, effect of temperature
upon, 158, 403
Matter, its definition, 4
Matter, living, 340, 353
Matter, states of, 399
Mechanical field, 369
Medium, necessity for, 33
Mental processes imply physical
conditions, 464
Mercury, 65
Meteors, 25, 31, 75
Microscope, magnifying powers,
18, 178
Mind and energy, 466
Mind and matter, 29, 470
Mind, a material habitat for, 29
Miracle defined, 462
Miracles possible, 423
Mirrors, 176
Molecular fatigue, 92
Molecular stability, 338
Molecules, loaded, 191
Molecules, long free path, 269
Molecules, number of, in
universe, 148
Molecules, size of, 15, 22, 54
Momentum, 88
Motion, antecedent of, 85
INDEX 489
Motion, kinds of, 54, 57, 58, 173
Motion, laws of, 83, 86
Motion, molecular and atomic,
58
Motion, transformations of, 377
Motion, velocity of, 59
Motor, electric, 254
Muscles, 343
Muscular work, 80
Musical instruments, 325
Musical ratios, 323
Musical sounds, 321
Nebula theory, 116
Neptune, discovery of, 105
Nerves, their functions, 346, 348
Newton, Sir Isaac, 34, 97, 99, 104
Noise, 323
of, 424
Ohm’s law, 227
Organic and inorganic matter,
difference between, 438
Phenomena, nature of, 70
Phenomena, unexplained, 423,
471
Phosphorescence, 272
Photography, 187
Physical fields, 358
Physical processes, reversible,
279
Physical universe a machine, 397
Physicists, prepossessions, 457
Pitch, 311
Plating, electro, 265
Polarization of molecules, 213,
263
Postulates of Physical Science,
427
Potential, electrical, 226
Power, needed for rapid
movement in air, 430
Principia, 36, 83
Prism, 165
Protoplasm, 337
Psychics, 471
Pulley, 381
Purpurine, 202
Push and pull, 379
Radiometer, 185
Reflection, 175
Reflex action, 206
Refraction, 165, 176
Resistance, electrical, 230, 257
Retina, its functions, 204
Rotations in ether, 282
INDEX 490
S´eances, phenomena at, 433, 454
Satellite, 82
Saturn, temperature of, 172
Science, no one independent, 452
Seeing, what is implied in, 441
Senses, 193, 444
Silver salts unstable, 190
Sirius, 173
Soap-bubbles, 12
Solar system, 395
Sound, characteristics, 314
Sound, origin of, 308, 431
Sound, range of, 315
Sound, velocity of, 315
Sound, vocal, 326
Space, 69
Space, navigation of, 184
Spark, electric, 268
Specialists, 446
Specific gravity, 8
Specific heat, 156
Spectroscope, 166
Spectrum analysis, 166
Spectrum, solar, 165, 169
Spirit disembodied, 431
Spiritualistic theory, 431
Stars, their distance, 23, 32
Stars, their motions, 173
Stars, their number, 22
Steam-engine, 135
Steam-engine, efficiency of, 136
Stress in ether, 110
Stress in glass, 109
Stress, electrical, 219, 236, 277
Stress, magnetic, 216
Sun, its age, 145
Sun, its distance, 32, 66
Sun, its heat, 145
Sun, its magnitude, 145
Sun, its structure, 170
Telegraph, 254
Telephone, 254
Temperature, 127
Temperature, maximum, 152
Temperature, table, 129
Terminology, electrical, 223
Tesla ether waves, 412
Thermodynamics, 133
Thermodynamics, electric, 208
Thermometer, 127
Thermometer, air, 130
Thermopile, 211
Thomson, Sir Wm., 40
Thought transference, 373, 472
Toepler-Holtz electrical machine,
353
Top, sleep of, 85
Transformations of motion, 386
Transparency, 175
Universe, atoms in, 23
Universe, its size, 32
INDEX 491
Vacuum, 55
Vacuum, a non-conductor, 268
Velocities, 59, 64, 66
Venus, 65
Vibrations per second, 62, 63
Vibrations, forced, 320
Vibrations, gaseous, 138
Vibrations, sympathetic, 298, 320
Vision of animals, 201
Vision, energy needed for, 198
Vision, hallucinations of, 198
Vision, phenomena of, 195
Vision, theory of, 201
Vital force, 336
Voice, 326
Volcanoes, 152
Vortex ring model, 412
Vortex ring theory of matter, 112
Vortex rings in air, 40
Vortex rings, properties of, 43, 85
Water decomposition, 261
Wave lengths of sound, 318
Waves, electric, 364
Weight, 72
Weights, standards of, 71
Welding, electric, 252
Work, measure of, 73, 75, 382
Work, muscular, 80
Work, standard of, 71
LEE AND SHEPARD
10 MILK STREET BOSTON
List of Books upon Various Subjects
QUABBIN
Sketches in a Small Town With Outlooks upon Puritan Life By
Francis H. Underwood LL.D. author of “Handbooks of English
Literature” “Man Proposes” “Lord of Himself” etc. Fully
illustrated Cloth $1.75
This work purports to give an account of the progress of a small New England
town; but it is of wider and deeper import; namely, a view of the development of the
narrow and sombre Puritan into the variously gifted and accomplished “Yankee” of today.
It concerns the state of literature and art in the early part of the present century,
and shows how the fairer conditions of modern times came into being.
In plan it is wholly unlike any modern book. It is not a town history, nor an
historical essay, nor a collection of reminiscences. Its chapters are mostly picturesque
descriptions of the old times, and show the “rude forefathers” at home, at church,
at town-meetings, at road-making, and in other scenes of their daily life. There are
sketches of the successive ministers, the schools, the quiltings, sleigh-rides, and other
rustic gatherings,—of the homely speech and manners, and of the complexities of
Yankee character.
It is believed that these graphic, tender, and humorous pictures will appeal to the
hearts and memories of New England people, and to their descendants along the line
of migration westward to the Mississippi and beyond.
The illustrations are from photographs taken from beautiful scenes in “Quabbin.”
Books Upon Various Subjects
UNIVERSAL PHONOGRAPHY or Short-hand by the “Allen
Method”
A self-instructor, whereby more speed than long-hand writing is
gained at the first lesson, and additional speed at each subsequent
lesson By G. G. Allen, Principal of the Allen Stenographic
Institute Boston 50 cents
There is scarcely any requirement so helpful to the student, scholar, scientist, or
professional man as short-hand writing. Heretofore all methods have required so long
a time before one could become so proficient as to make it of any advantage, that men
in middle life, or busy men, have not been able to give the time to learn it; but by the
“Allen Method” one can almost in “the idle moments of a busy life,” certainly in an
hour a day for two or three months, become so expert as to report a lecture verbatim.
MATTER, ETHER, AND MOTION
The Factors and Relations of Physical Science By Prof. A. E.
Dolbear Tufts College author of “The Telephone” “The Art of
Projecting” etc. Cloth $2.00
“Matter, Ether, and Motion,” the Factors and Relations of Physical Science, by
A. E. Dolbear, Ph.D. The author in this treatise presents to his readers the principles of
physical science. The chapters are arranged as Matter, Ether, Motion, Energy, Gravitation,
Heat, Ether Waves, Electricity, Chemism, Sound, Life, Physical Fields, Machines
and Mechanism. This is a tolerably comprehensive table, and introduces the student
to the principles on which, so far as at present known, the action of the universe seems
to depend.
Altogether this little treatise gives an insight into matters outside the common
range of serious study, and yet places the subject within reach of the student seeking
for knowledge. Although dealing with abstruse scientific topics, the style is lucid, and
the matter intelligible to ordinary thinkers and readers in search of information.—New
York Commercial Advertiser.
THE TELEPHONE
An account of the phenomena of electricity, magnetism, and sound
as involved in its action; with directions for making a speaking
telephone By Prof. A. E. Dolbear of Tufts College 50 cents
Books Upon Various Subjects
An interesting little book upon this most fascinating subject, which is treated in
a very clear and methodical way. First we have a thorough review of the discoveries
in electricity, then of magnetism, then of those in the study of sound,—pitch, velocity,
timbre, tone, resonance, sympathetic vibrations, etc. From these the telephone is
reached, and by them in a measure explained.—Hartford Courant.
THE ART OF PROJECTING
By Prof. A. E. Dolbear Ph.D. (Tufts College) New Edition revised
with additions 125 illustrations Cloth $2.00
A Manual of Experimentation in Physics, Chemistry, and Natural History with
the Porte Lumi`ere and the Magic Lantern; also with Electric Lights and Lamps and the
Production and Phenomena of Vortex Rings.
WHAT IS TO BE DONE–(Emergency Handbook)
A Handbook for the Nursery with Useful Hints for Children and
Adults By Robert B. Dixon M.D. Surgeon of the Fifth Massachusetts
Infantry, Physician to the Boston Dispensary Cloth
50 cents; paper 30 cents
Dr. Dixon, in this little “Emergency Handbook,” gives simple directions what to
do in a number of the most common cases that arise, either in home treatment of slight
accidents, or indispositions, or in the case of patients in more serious cases, until the
arrival of the physician. The book is worth its weight in gold, and ought to have a
place in every family library.—Providence Press.
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