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_THE ROMANCE OF SCIENCE_


THE MACHINERY OF THE UNIVERSE

MECHANICAL CONCEPTIONS OF
PHYSICAL PHENOMENA


BY
A. E. DOLBEAR, A.B., A.M., M.E., PH.D.

PROFESSOR OF PHYSICS AND ASTRONOMY, TUFTS COLLEGE, MASS.


PUBLISHED UNDER GENERAL LITERATURE COMMITTEE.


LONDON:
SOCIETY FOR PROMOTING CHRISTIAN KNOWLEDGE,
NORTHUMBERLAND AVENUE, W.C.;
43, QUEEN VICTORIA STREET, E.C.

BRIGHTON: 129, NORTH STREET.

NEW YORK: E. & J. B. YOUNG & CO.

1897.




PREFACE


For thirty years or more the expressions "Correlation of the Physical
Forces" and "The Conservation of Energy" have been common, yet few
persons have taken the necessary pains to think out clearly what
mechanical changes take place when one form of energy is transformed
into another.

Since Tyndall gave us his book called _Heat as a Mode of Motion_ neither
lecturers nor text-books have attempted to explain how all phenomena are
the necessary outcome of the various forms of motion. In general,
phenomena have been attributed to _forces_--a metaphysical term, which
explains nothing and is merely a stop-gap, and is really not at all
needful in these days, seeing that transformable modes of motion, easily
perceived and understood, may be substituted in all cases for forces.

In December 1895 the author gave a lecture before the Franklin Institute
of Philadelphia, on "Mechanical Conceptions of Electrical Phenomena," in
which he undertook to make clear what happens when electrical phenomena
appear. The publication of this lecture in _The Journal of the Franklin
Institute_ and in _Nature_ brought an urgent request that it should be
enlarged somewhat and published in a form more convenient for the
public. The enlargement consists in the addition of a chapter on the
"_Contrasted Properties of Matter and the Ether_," a chapter containing
something which the author believes to be of philosophical importance in
these days when electricity is so generally described as a phenomenon of
the ether.

A. E. DOLBEAR.




TABLE OF CONTENTS


CHAPTER I

Ideas of phenomena ancient and modern, metaphysical and
    mechanical--Imponderables--Forces, invented and
    discarded--Explanations--Energy, its factors, Kinetic
    and Potential--Motions, kinds and transformations
    of--Mechanical, molecular, and atomic--Invention of
    Ethers, Faraday's conceptions                            p. 7


CHAPTER II

Properties of Matter and Ether compared--Discontinuity
    _versus_ Continuity--Size of atoms--Astronomical
    distances--Number of atoms in the universe--Ether
    unlimited--Kinds of Matter, permanent qualities
    of--Atomic structure; vortex-rings, their
    properties--Ether structureless--Matter
    gravitative, Ether not--Friction in Matter, Ether
    frictionless--Chemical properties--Energy in
    Matter and in Ether--Matter as a transformer
    of Energy--Elasticity--Vibratory rates and
    waves--Density--Heat--Indestructibility of
    Matter--Inertia in Matter and in Ether--Matter
    not inert--Magnetism and Ether waves--States
    of Matter--Cohesion and chemism affected by
    temperature--Shearing stress in Solids and in
    Ether--Ether pressure--Sensation dependent upon
    Matter--Nervous system not affected by Ether
    states--Other stresses in Ether--Transformations
    of Motion--Terminology                                  p. 24


CHAPTER III

Antecedents of Electricity--Nature of what is
    transformed--Series of transformations for the
    production of light--Positive and negative
    Electricity--Positive and negative twists--Rotations
    about a wire--Rotation of an arc--Ether a
    non-conductor--Electro-magnetic waves--Induction
    and inductive action--Ether stress and atomic
    position--Nature of an electric current--Electricity
    a condition, not an entity                              p. 94




CHAPTER I

Ideas of phenomena ancient and modern, metaphysical and
    mechanical--Imponderables--Forces, invented and
    discarded--Explanations--Energy, its factors, Kinetic
    and Potential--Motions, kinds and transformations
    of--Mechanical, molecular, and atomic--Invention of
    Ethers, Faraday's conceptions.

'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 attract
    each other at near distances, and cohere if contiguous, and
    electric bodies operate at greater distances, as well repelling
    as attracting neighbouring corpuscles, and light is emitted,
    reflected, inflected, and heats bodies, and all sensation is
    excited, and members of animal bodies move at the command of
    the will.'--NEWTON, _Principia_.


In Newton's day the whole field of nature was practically lying fallow.
No fundamental principles were known until the law of gravitation was
discovered. This law was behind all the work of Copernicus, Kepler, and
Galileo, and what they had done needed interpretation. It was quite
natural that the most obvious and mechanical phenomena should first be
reduced, and so the _Principia_ was concerned with mechanical principles
applied to astronomical problems. To us, who have grown up familiar with
the principles and conceptions underlying them, all varieties of
mechanical phenomena seem so obvious, that it is difficult for us to
understand how any one could be obtuse to them; but the records of
Newton's time, and immediately after this, show that they were not so
easy of apprehension. It may be remembered that they were not adopted in
France till long after Newton's day. In spite of what is thought to be
reasonable, it really requires something more than complete
demonstration to convince most of us of the truth of an idea, should the
truth happen to be of a kind not familiar, or should it chance to be
opposed to our more or less well-defined notions of what it is or ought
to be. If those who labour for and attain what they think to be the
truth about any matter, were a little better informed concerning mental
processes and the conditions under which ideas grow and displace others,
they would be more patient with mankind; teachers of every rank might
then discover that what is often called stupidity may be nothing else
than mental inertia, which can no more be made active by simply willing
than can the movement of a cannon ball by a like effort. We _grow_ into
our beliefs and opinions upon all matters, and scientific ideas are no
exceptions.

Whewell, in his _History of the Inductive Sciences_, says that the
Greeks made no headway in physical science because they lacked
appropriate ideas. The evidence is overwhelming that they were as
observing, as acute, as reasonable as any who live to-day. With this
view, it would appear that the great discoverers must have been men who
started out with appropriate ideas: were looking for what they found.
If, then, one reflects upon the exceeding great difficulty there is in
discovering one new truth, and the immense amount of work needed to
disentangle it, it would appear as if even the most successful have but
indistinct ideas of what is really appropriate, and that their
mechanical conceptions become clarified by doing their work. This is not
always the fact. In the statement of Newton quoted at the head of this
chapter, he speaks of a spirit which lies hid in all gross bodies, etc.,
by means of which all kinds of phenomena are to be explained; but he
deliberately abandons that idea when he comes to the study of light, for
he assumes the existence and activity of light corpuscles, for which he
has no experimental evidence; and the probability is that he did this
because the latter conception was one which he could handle
mathematically, while he saw no way for thus dealing with the other. His
mechanical instincts were more to be trusted than his carefully
calculated results; for, as all know, what he called "spirits," is what
to-day we call the ether, and the corpuscular theory of light has now no
more than a historic interest. The corpuscular theory was a mechanical
conception, but each such corpuscle was ideally endowed with qualities
which were out of all relation with the ordinary matter with which it
was classed.

Until the middle of the present century the reigning physical philosophy
held to the existence of what were called imponderables. The phenomena
of heat were explained as due to an imponderable substance called
"caloric," which ordinary matter could absorb and emit. A hot body was
one which had absorbed an imponderable substance. It was, therefore, no
heavier than before, but it possessed ability to do work proportional to
the amount absorbed. Carnot's ideal engine was described by him in terms
that imply the materiality of heat. Light was another imponderable
substance, the existence of which was maintained by Sir David Brewster
as long as he lived. Electricity and magnetism were imponderable fluids,
which, when allied with ordinary matter, endowed the latter with their
peculiar qualities. The conceptions in each case were properly
mechanical ones _part_ (but not all) _of the time_; for when the
immaterial substances were dissociated from matter, where they had
manifested themselves, no one concerned himself to inquire as to their
whereabouts. They were simply off duty, but could be summoned, like the
genii in the story of Aladdin's Lamp. Now, a mechanical conception of
any phenomenon, or a mechanical explanation of any kind of action, must
be mechanical all the time, in the antecedents as well as the
consequents. Nothing else will do except a miracle.

During the fifty years, from about 1820 to 1870, a somewhat different
kind of explanation of physical events grew up. The interest that was
aroused by the discoveries in all the fields of physical science--in
heat, electricity, magnetism and chemistry--by Faraday, Joule,
Helmholtz, and others, compelled a change of conceptions; for it was
noticed that each special kind of phenomenon was preceded by some other
definite and known kind; as, for instance, that chemical action preceded
electrical currents, that mechanical or electrical activity resulted
from changing magnetism, and so on. As each kind of action was believed
to be due to a special force, there were invented such terms as
mechanical force, electrical force, magnetic, chemical and vital forces,
and these were discovered to be convertible into one another, and the
"doctrine of the correlation of the physical forces" became a common
expression in philosophies of all sorts. By "convertible into one
another," was meant, that whenever any given force appeared, it was at
the expense of some other force; thus, in a battery chemical force was
changed into electrical force; in a magnet, electrical force was changed
into magnetic force, and so on. The idea here was the _transformation of
forces_, and _forces_ were not so clearly defined that one could have a
mechanical idea of just what had happened. That part of the philosophy
was no clearer than that of the imponderables, which had largely dropped
out of mind. The terminology represented an advance in knowledge, but
was lacking in lucidity, for no one knew what a force of any kind was.

The first to discover this and to repudiate the prevailing terminology
were the physiologists, who early announced their disbelief in a vital
force, and their belief that all physiological activities were of purely
physical and chemical origin, and that there was no need to assume any
such thing as a vital force. Then came the discovery that chemical
force, or affinity, had only an adventitious existence, and that, at
absolute zero, there was no such activity. The discovery of, or rather
the appreciation of, what is implied by the term _absolute zero_, and
especially of the nature of heat itself, as expressed in the statement
that heat is a mode of motion, dismissed another of the so-called forces
as being a metaphysical agency having no real existence, though standing
for phenomena needing further attention and explanation; and by
explanation is meant _the presentation of the mechanical antecedents for
a phenomenon, in so complete a way that no supplementary or unknown
factors are necessary_. The train moves because the engine pulls it; the
engine pulls because the steam pushes it. There is no more necessity for
assuming a steam force between the steam and the engine, than for
assuming an engine force between the engine and the train. All the
processes are mechanical, and have to do only with ordinary matter and
its conditions, from the coal-pile to the moving freight, though there
are many transformations of the forms of motion and of energy between
the two extremes.

During the past thirty years there has come into common use another
term, unknown in any technical sense before that time, namely, _energy_.
What was once called the conservation of force is now called the
conservation of energy, and we now often hear of forms of energy. Thus,
heat is said to be a form of energy, and the forms of energy are
convertible into one another, as the so-called forces were formerly
supposed to be transformable into one another. We are asked to consider
gravitative energy, heat energy, mechanical energy, chemical energy, and
electrical energy. When we inquire what is meant by energy, we are
informed that it means ability to do work, and that work is measurable
as a pressure into a distance, and is specified as foot-pounds. A mass
of matter moves because energy has been spent upon it, and has acquired
energy equal to the work done on it, and this is believed to hold true,
no matter what the kind of energy was that moved it. If a body moves, it
moves because another body has exerted pressure upon it, and its energy
is called _kinetic energy_; but a body may be subject to pressure and
not move appreciably, and then the body is said to possess potential
energy. Thus, a bent spring and a raised weight are said to possess
potential energy. In either case, _an energized body receives its energy
by pressure, and has ability to produce pressure on another body_.
Whether or not it does work on another body depends on the rigidity of
the body it acts upon. In any case, it is simply a mechanical
action--body A pushes upon body B (Fig. 1). There is no need to assume
anything more mysterious than mechanical action. Whether body B moves
this way or that depends upon the direction of the push, the point of
its application. Whether the body be a mass as large as the earth or as
small as a molecule, makes no difference in that particular. Suppose,
then, that _a_ (Fig. 2) spends its energy on _b_, _b_ on _c_, _c_ on
_d_, and so on. The energy of _a_ gives translatory motion to _b_, _b_
sets _c_ vibrating, and _c_ makes _d_ spin on some axis. Each of these
has had energy spent on it, and each has some form of energy different
from the other, but no new factor has been introduced between _a_ and
_d_, and the only factor that has gone from _a_ to _d_ has been
motion--motion that has had its direction and quality changed, but not
its nature. If we agree that energy is neither created nor annihilated,
by any physical process, and if we assume that _a_ gave to _b_ all its
energy, that is, all its motion; that _b_ likewise gave its all to _c_,
and so on; then the succession of phenomena from _a_ to _d_ has been
simply the transference of a definite amount of motion, and therefore of
energy, from the one to the other; for _motion has been the only
variable factor_. If, furthermore, we should agree to call the
translatory motion [alpha], the vibratory motion [beta], the
rotary [gamma], then we should have had a conversion of [alpha]
into [beta], of [beta] into [gamma]. If we should consider
the amount of transfer motion instead of the kind of motion, we should
have to say that the [alpha] energy had been transformed into
[beta] and the [beta] into [gamma].

[Illustration: FIG. 1.]

[Illustration: FIG. 2.]

What a given amount of energy will do depends only upon its _form_, that
is, the kind of motion that embodies it.

The energy spent upon a stone thrown into the air, giving it translatory
motion, would, if spent upon a tuning fork, make it sound, but not move
it from its place; while if spent upon a top, would enable the latter to
stand upon its point as easily as a person stands on his two feet, and
to do other surprising things, which otherwise it could not do. One can,
without difficulty, form a mechanical conception of the whole series
without assuming imponderables, or fluids or forces. Mechanical motion
only, by pressure, has been transferred in certain directions at certain
rates. Suppose now that some one should suddenly come upon a spinning
top (Fig. 3) while it was standing upon its point, and, as its motion
might not be visible, should cautiously touch it. It would bound away
with surprising promptness, and, if he were not instructed in the
mechanical principles involved, he might fairly well draw the conclusion
that it was actuated by other than simple mechanical principles, and,
for that reason, it would be difficult to persuade him that there was
nothing essentially different in the body that appeared and acted thus,
than in a stone thrown into the air; nevertheless, that statement would
be the simple truth.

[Illustration: FIG. 3.]

All our experience, without a single exception, enforces the proposition
that no body moves in any direction, or in any way, except when some
other body _in contact_ with it presses upon it. The action is direct.
In Newton's letter to his friend Bentley, he says--"That one body
should act upon another through empty space, without the mediation of
anything else by and through which their action and pressure 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."

For mathematical purposes, it has sometimes been convenient to treat a
problem as if one body could act upon another without any physical
medium between them; but such a conception has no degree of rationality,
and I know of no one who believes in it as a fact. If this be granted,
then our philosophy agrees with our experience, and every body moves
because it is pushed, and the mechanical antecedent of every kind of
phenomenon is to be looked for in some adjacent body possessing
energy--that is, the ability to push or produce pressure.

It must not be forgotten that energy is not a simple factor, but is
always a product of two factors--a mass with a velocity, a mass with a
temperature, a quantity of electricity into a pressure, and so on. One
may sometimes meet the statement that matter and energy are the two
realities; both are spoken of as entities. It is much more philosophical
to speak of matter and motion, for in the absence of motion there is no
energy, and the energy varies with the amount of motion; and
furthermore, to understand any manifestation of energy one must inquire
what kind of motion is involved. This we do when we speak of mechanical
energy as the energy involved in a body having a translatory motion;
also, when we speak of heat as a vibratory, and of light as a wave
motion. To speak of energy without stating or implying these
distinctions, is to speak loosely and to keep far within the bounds of
actual knowledge. To speak thus of a body possessing energy, or
expending energy, is to imply that the body possesses some kind of
motion, and produces pressure upon another body because it has motion.
Tait and others have pointed out the fact, that what is called potential
energy must, in its nature, be kinetic. Tait says--"Now it is impossible
to conceive of a truly dormant form of energy, whose magnitude should
depend, in any way, upon the unit of time; and we are forced to conclude
that potential energy, like kinetic energy, depends (even if unexplained
or unimagined) upon motion." All this means that it is now too late to
stop with energy as a final factor in any phenomenon, that the _form of
motion_ which embodies the energy is the factor that determines _what_
happens, as distinguished from how _much_ happens. Here, then, are to be
found the distinctions which have heretofore been called forces; here
is embodied the proof that direct pressure of one body upon another is
what causes the latter to move, and that the direction of movement
depends on the point of application, with reference to the centre
of mass.

It is needful now to look at the other term in the product we call
energy, namely, the substance moving, sometimes called matter or mass.
It has been mentioned that the idea of a medium filling space was
present to Newton, but his gravitation problem did not require that he
should consider other factors than masses and distances. The law of
gravitation as considered by him was--Every particle of matter attracts
every other particle of matter with a stress which is proportional to
the product of their masses, and inversely to the squares of the
distance between them. Here we are concerned only with the statement
that every particle of matter attracts every other particle of matter.
Everything then that possesses gravitative attraction is matter in the
sense in which that term is used in this law. If there be any other
substance in the universe that is not thus subject to gravitation, then
it is improper to call it matter, otherwise the law should read, "Some
particles of matter attract," etc., which will never do.

We are now assured that there is something else in the universe which
has no gravitative property at all, namely, the ether. It was first
imagined in order to account for the phenomena of light, which was
observed to take about eight minutes to come from the sun to the earth.
Then Young applied the wave theory to the explanation of polarization
and other phenomena; and in 1851 Foucault proved experimentally that the
velocity of light was less in water than in air, as it should be if the
wave theory be true, and this has been considered a crucial experiment
which took away the last hope for the corpuscular theory, and
demonstrated the existence of the ether as a space-filling medium
capable of transmitting light-waves known to have a velocity of 186,000
miles per second. It was called the luminiferous ether, to distinguish
it from other ethers which had also been imagined, such as electric
ether for electrical phenomena, magnetic ether for magnetic phenomena,
and so on--as many ethers, in fact, as there were different kinds of
phenomena to be explained.

It was Faraday who put a stop to the invention of ethers, by suggesting
that the so-called luminiferous ether might be the one concerned in all
the different phenomena, and who pointed out that the arrangement of
iron filings about a magnet was indicative of the direction of the
stresses in the ether. This suggestion did not meet the approval of the
mathematical physicists of his day, for it necessitated the abandonment
of the conceptions they had worked with, as well as the terminology
which had been employed, and made it needful to reconstruct all their
work to make it intelligible--a labour which was the more distasteful as
it was forced upon them by one who, although expert enough in
experimentation, was not a mathematician, and who boasted that the most
complicated mathematical work he ever did was to turn the crank of a
calculating machine; who did all his work, formed his conclusions, and
then said--"The work is done; hand it over to the computers."

It has turned out that Faraday's mechanical conceptions were right.
Every one now knows of Maxwell's work, which was to start with Faraday's
conceptions as to magnetic phenomena, and follow them out to their
logical conclusions, applying them to molecules and the reactions of the
latter upon the ether. Thus he was led to conclude that light was an
electro-magnetic phenomenon; that is, that the waves which constitute
light, and the waves produced by changing magnetism were identical in
their nature, were in the same medium, travelled with the same velocity,
were capable of refraction, and so on. Now that all this is a matter of
common knowledge to-day, it is curious to look back no further than ten
years. Maxwell's conclusions were adopted by scarcely a physicist in
the world. Although it was known that inductive action travelled with
finite velocity in space, and that an electro-magnet would affect the
space about it practically inversely as the square of the distance, and
that such phenomena as are involved in telephonic induction between
circuits could have no other meaning than the one assigned by Maxwell,
yet nearly all the physicists failed to form the only conception of it
that was possible, and waited for Hertz to devise apparatus for
producing interference before they grasped it. It was even then so new,
to some, that it was proclaimed to be a demonstration of the existence
of the ether itself, as well as a method of producing waves short enough
to enable one to notice interference phenomena. It is obvious that Hertz
himself must have had the mechanics of wave-motion plainly in mind, or
he would not have planned such experiments. The outcome of it all is,
that we now have experimental demonstration, as well as theoretical
reason for believing, that the ether, once considered as only
luminiferous, is concerned in all electric and magnetic phenomena, and
that waves set up in it by electro-magnetic actions are capable of being
reflected, refracted, polarized, and twisted, in the same way as
ordinary light-waves can be, and that the laws of optics are applicable
to both.




CHAPTER II

PROPERTIES OF MATTER AND ETHER

Properties of Matter and Ether compared--Discontinuity
    _versus_ Continuity--Size of atoms--Astronomical
    distances--Number of atoms in the universe--Ether
    unlimited--Kinds of Matter, permanent qualities
    of--Atomic structure; vortex-rings, their
    properties--Ether structureless--Matter
    gravitative, Ether not--Friction in Matter, Ether
    frictionless--Chemical properties--Energy in
    Matter and in Ether--Matter as a transformer
    of Energy--Elasticity--Vibratory rates and
    waves--Density--Heat--Indestructibility of
    Matter--Inertia in Matter and in Ether--Matter
    not inert--Magnetism and Ether waves--States
    of Matter--Cohesion and chemism affected by
    temperature--Shearing stress in Solids and in
    Ether--Ether pressure--Sensation dependent upon
    Matter--Nervous system not affected by Ether
    states--Other stresses in Ether--Transformations
    of Motion--Terminology.


A common conception of the ether has been that it is a finer-grained
substance than ordinary matter, but otherwise so like the latter that
the laws found to hold good with matter were equally applicable to the
ether, and hence the mechanical conceptions formed from experience in
regard to the one have been transferred to the other, and the properties
belonging to one, such as density, elasticity, etc., have been asserted
as properties of the other.

There is so considerable a body of knowledge bearing upon the
similarities and dissimilarities of these two entities that it will be
well to compare them. After such comparison one will be better able to
judge of the propriety of assuming them to be subject to identical laws.


1. MATTER IS DISCONTINUOUS.

Matter is made up of atoms having dimensions approximately determined to
be in the neighbourhood of the one fifty-millionth of an inch in
diameter. These atoms may have various degrees of aggregation;--they may
be in practical contact, as in most solid bodies such as metals and
rocks; in molecular groupings as in water, and in gases such as
hydrogen, oxygen, and so forth, where two, three, or more atoms cohere
so strongly as to enable the molecules to act under ordinary
circumstances like simple particles. Any or all of these molecules and
atoms may be separated by any assignable distance from each other. Thus,
in common air the molecules, though rapidly changing their positions,
are on the average about two hundred and fifty times their own diameter
apart. This is a distance relatively greater than the distance apart of
the earth and the moon, for two hundred and fifty times the diameter of
the earth will be 8000 × 250 = 2,000,000 miles, while the distance to
the moon is but 240,000 miles. The sun is 93,000,000 miles from the
earth, and the most of the bodies of the solar system are still more
widely separated, Neptune being nearly 3000 millions of miles from the
sun. As for the fixed stars, they are so far separated from us that, at
the present rate of motion of the solar system in its drift through
space--500 millions of miles in a year--it would take not less than
40,000 years to reach the nearest star among its neighbours, while for
the more remote ones millions of years must be reckoned. The huge space
separating these masses is practically devoid of matter; it is a vacuum.


THE ETHER IS CONTINUOUS.

The idea of continuity as distinguished from discontinuity may be gained
by considering what would be made visible by magnification. Water
appears to the eye as if it were without pores, but if sugar or salt be
put into it, either will be dissolved and quite disappear among the
molecules of the water as steam does in the air, which shows that there
are some unoccupied spaces between the molecules. If a microscope be
employed to magnify a minute drop of water it still shows the same lack
of structure as that looked at with the unaided eye. If the magnifying
power be the highest it may reveal a speck as small as the
hundred-thousandth part of an inch, yet the speck looks no different in
character. We know that water is composed of two different kinds of
atoms, hydrogen and oxygen, for they can be separated by chemical means
and kept in separate bottles, and again made to combine to form water
having all the qualities that belonged to it before it was decomposed.
If a very much higher magnifying power were available, we should
ultimately be able to see the individual water molecules, and recognize
their hydrogen and oxygen constituents by their difference in size, rate
of movements, and we might possibly separate them by mechanical methods.
What one would see would be something very different in structure from
the water as it appears to our eyes. If the ether were similarly to be
examined through higher and still higher magnifying powers, even up to
infinity, there is no reason for thinking that the last examination
would show anything different in structure or quality from that which
was examined with low power or with no microscope at all. This is all
expressed by saying that the ether is a continuous substance, without
interstices, that it fills space completely, and, unlike gases,
liquids, and solids, is incapable of absorbing or dissolving anything.


2. MATTER IS LIMITED.

There appears to be a definite amount of matter in the visible universe,
a definite number of molecules and atoms. How many molecules there are
in a cubic inch of air under ordinary pressure has been determined, and
is represented approximately by a huge number, something like a thousand
million million millions.

When the diameter of a molecule has been measured, as it has been
approximately, and found to be about one fifty-millionth of an inch,
then fifty million in a row would reach an inch, and the cube of fifty
million is 125,000,000000,000000,000000, one hundred and twenty-five
thousand million million millions. In a cubic foot there will of course
be 1728 times that number. One may if one likes find how many there may
be in the earth, and moon, sun and planets, for the dimensions of them
are all very well known. Only the multiplication table need be used, and
the sum of all these will give how many molecules there are in the solar
system. If one should feel that the number thus obtained was not very
accurate, he might reflect that if there were ten times as many it would
add but another cipher to a long line of similar ones and would not
materially modify it. The point is that there is a definite, computable
number. If one will then add to these the number of molecules in the
more distant stars and nebulæ, of which there are visible about
100,000,000, making such estimate of their individual size as he thinks
prudent, the sum of all will give the number of molecules in the visible
universe. The number is not so large but it can be written down in a
minute or two. Those who have been to the pains to do the sum say it may
be represented by seven followed by ninety-one ciphers. One could easily
compute how many molecules so large a space would contain if it were
full and as closely packed as they are in a drop of water, but there
would be a finite and not an infinite number, and therefore there is a
limited number of atoms in the visible universe.


THE ETHER IS UNLIMITED.

The evidence for this comes to us from the phenomena of light.
Experimentally, ether waves of all lengths are found to have a velocity
of 186,000 miles in a second. It takes about eight minutes to reach us
from the sun, four hours from Neptune the most distant planet, and from
the nearest fixed star about three and a half years. Astronomers tell us
that some visible stars are so distant that their light requires not
less than ten thousand years and probably more to reach us, though
travelling at the enormous rate of 186,000 miles a second. This means
that the whole of space is filled with this medium. If there were any
vacant spaces, the light would fail to get through them, and stars
beyond them would become invisible. There are no such vacant spaces, for
any part of the heavens shows stars beaming continuously, and every
increase in telescopic power shows stars still further removed than any
seen before. The whole of this intervening space must therefore be
filled with the ether. Some of the waves that reach us are not more than
the hundred-thousandth of an inch long, so there can be no crack or
break or absence of ether from so small a section as the
hundred-thousandth of an inch in all this great expanse. More than this.
No one can think that the remotest visible stars are upon the boundary
of space, that if one could get to the most distant star he would have
on one side the whole of space while the opposite side would be devoid
of it. Space we know is of three dimensions, and a straight line may be
prolonged in any direction to an infinite distance, and a ray of light
may travel on for an infinite time and come to no end provided space be
filled with ether.

How long the sun and stars have been shining no one knows, but it is
highly probable that the sun has existed for not less than 1000 million
years, and has during that time been pouring its rays as radiant energy
into space. If then in half that time, or 500 millions of years, the
light had somewhere reached a boundary to the ether, it could not have
gone beyond but would have been reflected back into the ether-filled
space, and such part of the sky would be lit up by this reflected light.
There is no indication that anything like reflection comes to us from
the sky. This is equivalent to saying that the ether fills space in
every direction away from us to an unlimited distance, and so far is
itself unlimited.


3. MATTER IS HETEROGENEOUS.

The various kinds of matter we are acquainted with are commonly called
the elements. These when combined in various ways exhibit characteristic
phenomena which depend upon the kinds of matter, the structure and
motions which are involved. There are some seventy different kinds of
this elemental matter which may be identified as constituents of the
earth. Many of the same elements have been identified in the sun and
stars, such for instance as hydrogen, carbon, and iron. Such phenomena
lead us to conclude that the kinds of matter elsewhere in the universe
are identical with such as we are familiar with, and that elsewhere the
variety is as great. The qualities of the elements, within a certain
range of temperature, are permanent; they are not subject to
fluctuations, though the qualities of combinations of them may vary
indefinitely. The elements therefore may be regarded as retaining their
identity in all ordinary experience.


THE ETHER IS HOMOGENEOUS.

One part of the ether is precisely like any other part everywhere and
always, and there are no such distinctions in it as correspond with the
elemental forms of matter.


4. MATTER IS ATOMIC.

There is an ultimate particle of each one of the elements which is
practically absolute and known as an atom. The atom retains its identity
through all combinations and processes. It may be here or there, move
fast or slow, but its atomic form persists.


THE ETHER IS NON-ATOMIC.

One might infer, from what has already been said about continuity, that
the ether could not be constituted of separable particles like masses of
matter; for no matter how minute they might be, there would be
interspaces and unoccupied spaces which would present us with phenomena
which have never been seen. It is the general consensus of opinion
among those who have studied the subject that the ether is not atomic in
structure.


5. MATTER HAS DEFINITE STRUCTURE.

Every atom of every element is so like every other atom of the same
element as to exhibit the same characteristics, size, weight, chemical
activity, vibratory rate, etc., and it is thus shown conclusively that
the structural form of the elemental particles is the same for each
element, for such characteristic reactions as they exhibit could hardly
be if they were mechanically unlike.

Of what form the atoms of an element may be is not very definitely
known. The earlier philosophers assumed them to be hard round particles,
but later thinkers have concluded that atoms of such a character are
highly improbable, for they could not exhibit in this case the
properties which the elements do exhibit. They have therefore dismissed
such a conception from consideration. In place of this hypothesis has
been substituted a very different idea, namely, that an atom is a
vortex-ring[1] of ether floating in the ether, as a smoke-ring puffed
out by a locomotive in still air may float in the air and show various
phenomena.

[Footnote 1: Vortex-rings for illustration may be made by having a
wooden box about a foot on a side, with a round orifice in the middle of
one side, and the side opposite covered with stout cloth stretched tight
over a framework. A saucer containing strong ammonia water, and another
containing strong hydrochloric acid, will cause dense fumes in the box,
and a tap with the hand upon the cloth back will force out a ring from
the orifice. These may be made to follow and strike each other,
rebounding and vibrating, apparently attracting each other and being
attracted by neighbouring bodies.

By filling the mouth with smoke, and pursing the lips as if to make the
sound _o_, one may make fifteen or twenty small rings by snapping the
cheek with the finger.]

A vortex-ring produced in the air behaves in the most surprising manner.

[Illustration: FIG. 4.--Method of making vortex-rings and their
behaviour.]

1. It retains its ring form and the same material rotating as it
starts with.

2. It can travel through the air easily twenty or thirty feet in a
second without disruption.

3. Its line of motion when free is always at right angles to the
plane of the ring.

4. It will not stand still unless compelled by some object. If
stopped in the air it will start up itself to travel on without
external help.

5. It possesses momentum and energy like a solid body.

6. It is capable of vibrating like an elastic body, making a
definite number of such vibrations per second, the degree of
elasticity depending upon the rate of vibration. The swifter the
rotation, the more rigid and elastic it is.

7. It is capable of spinning on its own axis, and thus having rotary
energy as well as translatory and vibratory.

8. It repels light bodies in front of it, and attracts into itself
light bodies in its rear.

9. If projected along parallel with the top of a long table, it will
fall upon it every time, just as a stone thrown horizontally will
fall to the ground.

10. If two rings of the same size be travelling in the same line,
and the rear one overtakes the other, the front one will enlarge its
diameter, while the rear one will contract its own till it can go
through the forward one, when each will recover its original
diameter, and continue on in the same direction, but vibrating,
expanding and contracting their diameters with regularity.

11. If two rings be moving in the same line, but in opposite
directions, they will repel each other when near, and thus retard
their speed. If one goes through the other, as in the former case,
it may quite lose its velocity, and come to a standstill in the air
till the other has moved on to a distance, when it will start up in
its former direction.

12. If two rings be formed side by side, they will instantly collide
at their edges, showing strong attraction.

13. If the collision does not destroy them, they may either break
apart at the point of the collision, and then weld together into a
single ring with twice the diameter, and then move on as if a single
ring had been formed, or they may simply bounce away from each
other, in which case they always rebound _in a plane_ at right
angles to the plane of collision. That is, if they collided on their
sides, they would rebound so that one went up and the other down.

14. Three may in like manner collide and fuse into a single ring.

Such rings formed in air by a locomotive may rise wriggling in the air
to the height of several hundred feet, but they are soon dissolved and
disappear. This is because the friction and viscosity of the air robs
the rings of their substance and energy. If the air were without
friction this could not happen, and the rings would then be persistent,
and would retain all their qualities.

Suppose then that such rings were produced in a medium without friction
as the ether is believed to be, they would be permanent structures with
a variety of properties. They would occupy space, have definite form and
dimensions, momentum, energy, attraction and repulsion, elasticity; obey
the laws of motion, and so far behave quite like such matter as we know.
For such reasons it is thought by some persons to be not improbable
that the atoms of matter are minute vortex-rings of ether in the ether.
That which distinguishes the atom from the ether is the form of motion
which is embodied in it, and if the motion were simply arrested, there
would be nothing to distinguish the atom from the ether into which it
dissolved. In other words, such a conception makes the atoms of matter a
form of motion of the ether, and not a created something put into the
ether.


THE ETHER IS STRUCTURELESS.

If the ether be the boundless substance described, it is clear it can
have no form as a whole, and if it be continuous it can have no minute
structure. If not constituted of atoms or molecules there is nothing
descriptive that can be said about it. A molecule or a particular mass
of matter could be identified by its form, and is thus in marked
contrast with any portion of ether, for the latter could not be
identified in a similar way. One may therefore say that the ether is
formless.


6. MATTER IS GRAVITATIVE.

The law of gravitation is held as being universal. According to it every
particle of matter in the universe attracts every other particle. The
evidence for this law in the solar system is complete. Sun, planets,
satellites, comets and meteors are all controlled by gravitation, and
the movements of double stars testify to its activity among the more
distant bodies of the universe. The attraction does not depend upon the
kind of matter nor the arrangement of molecules or atoms, but upon the
amount or mass of matter present, and if it be of a definite kind of
matter, as of hydrogen or iron, the gravitative action is proportional
to the number of atoms.


THE ETHER IS GRAVITATIONLESS.

One might infer already that if the ether were structureless, physical
laws operative upon such material substances as atoms could not be
applicable to it, and so indeed all the evidence we have shows that
gravitation is not one of its properties. If it were, and it behaved in
any degree like atomic structures, it would be found to be denser in the
neighbourhood of large bodies like the earth, planets, and the sun.
Light would be turned from its straight path while travelling in such
denser medium, or made to move with less velocity. There is not the
slightest indication of any such effect anywhere within the range of
astronomical vision.

Gravitation then is a property belonging to matter and not to ether.
The impropriety of thinking or speaking of the ether as matter of any
kind will be apparent if one reflects upon the significance of the law
of gravitation as stated. Every particle of matter in the universe
attracts every other particle. If there be anything else in the universe
which has no such quality, then it should not be called matter, else the
law should read: Some particles of matter attract some other particles,
which would be no law at all, for a real physical law has no exceptions
any more than the multiplication table has. Physical laws are physical
relations, and all such relations are quantitative.


7. MATTER IS FRICTIONABLE.

A bullet shot into the air has its velocity continuously reduced by the
air, to which its energy is imparted by making it move out of its way. A
railway train is brought to rest by the friction brake upon the wheels.
The translatory energy of the train is transformed into the molecular
energy called heat. The steamship requires to propel it fast, a large
amount of coal for its engines, because the water in which it moves
offers great friction--resistance which must be overcome. Whenever one
surface of matter is moved in contact with another surface there is a
resistance called friction, the moving body loses its rate of motion,
and will presently be brought to rest unless energy be continuously
supplied. This is true for masses of matter of all sizes and with all
kinds of motion. Friction is the condition for the transformation of all
kinds of mechanical motions into heat. The test of the amount of
friction is the rate of loss of motion. A top will spin some time in the
air because its point is small. It will spin longer on a plate than on
the carpet, and longer in a vacuum than in the air, for it does not have
the air friction to resist it, and there is no kind or form of matter
not subject to frictional resistance.


THE ETHER IS FRICTIONLESS.

The earth is a mass of matter moving in the ether. In the equatorial
region the velocity of a point is more than a thousand miles in an hour,
for the circumference of the earth is 25,000 miles, and it turns once on
its axis in 24 hours, which is the length of the day. If the earth were
thus spinning in the atmosphere, the latter not being in motion, the
wind would blow with ten times hurricane velocity. The friction would be
so great that nothing but the foundation rocks of the earth's crust
could withstand it, and the velocity of rotation would be reduced
appreciably in a relatively short time. The air moves along with the
earth as a part of it, and consequently no such frictional destruction
takes place, but the earth rotates in the ether with that same rate, and
if the ether offered resistance it would react so as to retard the
rotation and increase the length of the day. Astronomical observations
show that the length of the day has certainly not changed so much as the
tenth of a second during the past 2000 years. The earth also revolves
about the sun, having a speed of about 19 miles in a second, or 68,000
miles an hour. This motion of the earth and the other planets about the
sun is one of the most stable phenomena we know. The mean distance and
period of revolution of every planet is unalterable in the long run. If
the earth had been retarded by its friction in the ether the length of
the year would have been changed, and astronomers would have discovered
it. They assert that a change in the length of a year by so much as the
hundredth part of a second has not happened during the past thousand
years. This then is testimony, that a velocity of nineteen miles a
second for a thousand years has produced no effect upon the earth's
motion that is noticeable. Nineteen miles a second is not a very swift
astronomical motion, for comets have been known to have a velocity of
400 miles a second when in the neighbourhood of the sun, and yet they
have not seemed to suffer any retardation, for their orbits have not
been shortened. Some years ago a comet was noticed to have its periodic
time shortened an hour or two, and the explanation offered at first was
that the shortening was due to friction in the ether although no other
comet was thus affected. The idea was soon abandoned, and to-day there
is no astronomical evidence that bodies having translatory motion in the
ether meet with any frictional resistance whatever. If a stone could be
thrown in interstellar space with a velocity of fifty feet a second it
would continue to move in a straight line with the same speed for any
assignable time.

As has been said, light moves with the velocity of 186,000 miles per
second, and it may pursue its course for tens of thousands of years.
There is no evidence that it ever loses either its wave-length or
energy. It is not transformed as friction would transform it, else there
would be some distance at which light of given wave-length and amplitude
would be quite extinguished. The light from distant stars would be
different in character from that coming from nearer stars. Furthermore,
as the whole solar system is drifting in space some 500,000,000 of miles
in a year, new stars would be coming into view in that direction, and
faint stars would be dropping out of sight in the opposite direction--a
phenomenon which has not been observed. Altogether the testimony seems
conclusive that the ether is a frictionless medium, and does not
transform mechanical motion into heat.


8. MATTER IS ÆOLOTROPIC.

That is, its properties are not alike in all directions. Chemical
phenomena, crystallization, magnetic and electrical phenomena show each
in their way that the properties of atoms are not alike on opposite
faces. Atoms combine to form molecules, and molecules arrange themselves
in certain definite geometric forms such as cubes, tetrahedra, hexagonal
prisms and stellate forms, with properties emphasized on certain faces
or ends. Thus quartz will twist a ray of light in one direction or the
other, depending upon the arrangement which may be known by the external
form of the crystal. Calc spar will break up a ray of light into two
parts if the light be sent through it in certain directions, but not if
in another. Tourmaline polarizes light sent through its sides and
becomes positively electrified at one end while being heated. Some
substances will conduct sound or light or heat or electricity better in
one direction than in another. All matter is magnetic in some degree,
and that implies polarity. If one will recall the structure of a
vortex-ring, he will see how all the motion is inward on one side and
outward on the other, which gives different properties to the two sides:
a push away from it on one side and a pull toward it on the other.


THE ETHER IS ISOTROPIC.

That is, its properties are alike in every direction. There is no
distinction due to position. A mass of matter will move as freely in one
direction as in another; a ray of light of any wave-length will travel
in it in one direction as freely as in any other; neither velocity nor
direction are changed by the action of the ether alone.


9. MATTER IS CHEMICALLY SELECTIVE.

When the elements combine to form molecules they always combine in
definite ways and in definite proportions. Carbon will combine with
hydrogen, but will drop it if it can get oxygen. Oxygen will combine
with iron or lead or sodium, but cannot be made to combine with
fluorine. No more than two atoms of oxygen can be made to unite with one
carbon atom, nor more than one hydrogen with one chlorine atom. There is
thus an apparent choice for the kind and number of associates in
molecular structure, and the instability of a molecule depends
altogether upon the presence in its neighbourhood of other atoms for
which some of the elements in the molecule have a stronger attraction
or affinity than they have for the atoms they are now combined with.
Thus iron is not stable in the presence of water molecules, and it
becomes iron oxide; iron oxide is not stable in the presence of hot
sulphur, it becomes an iron sulphide. All the elements are thus
selective, and it is by such means that they may be chemically
identified.

There is no phenomenon in the ether that is comparable with this.
Evidently there could not be unless there were atomic structures having
in some degree different characteristics which we know the ether to be
without.


10. THE ELEMENTS OF MATTER ARE HARMONICALLY RELATED.

It is possible to arrange the elements in the order of their atomic
weights in columns which will show communities of property. Newlands,
Mendeléeff, Meyer, and others have done this. The explanation for such
an arrangement has not yet been forthcoming, but that it expresses a
real fact is certain, for in the original scheme there were several gaps
representing undiscovered elements, the properties of which were
predicted from that of their associates in the table. Some of these have
since been discovered, and their atomic weight and physical properties
accord with those predicted.

With the ether such a scheme is quite impossible, for the very evident
reason that there are no different things to have relation with each
other. Every part is just like every other part. Where there are no
differences and no distinctions there can be no relations. The ether is
quite harmonic without relations.


11. MATTER EMBODIES ENERGY.

So long as the atoms of matter were regarded as hard round particles,
they were assumed to be inert and only active when acted upon by what
were called forces, which were held to be entities of some sort,
independent of matter. These could pull or push it here or there, but
the matter was itself incapable of independent activity. All this is now
changed, and we are called upon to consider every atom as being itself a
form of energy in the same sense as heat or light are forms of energy,
the energy being embodied in particular forms of motion. Light, for
instance, is a wave motion of the ether. An atom is a rotary ring of
ether. Stop the wave motion, and the light would be annihilated. Stop
the rotation, and the atom would be annihilated for the same reason. As
the ray of light is a particular embodiment of energy, and has no
existence apart from it, so an atom is to be regarded as an embodiment
of energy. On a previous page it is said that energy is the ability of
one body to act upon and move another in some degree. An atom of any
kind is not the inert thing it has been supposed to be, for it can do
something. Even at absolute zero, when all its vibratory or heat energy
would be absent, it would be still an elastic whirling body pulling upon
every other atom in the universe with gravitational energy, twisting
other atoms into conformity with its own position with its magnetic
energy; and, if such ether rings are like the rings which are made in
air, will not stand still in one place even if no others act upon it,
but will start at once by its own inherent energy to move in a right
line at right angles to its own plane and in the direction of the whirl
inside the ring. Two rings of wood or iron might remain in contact with
each other for an indefinite time, but vortex-rings will not, but will
beat each other away as two spinning tops will do if they touch ever so
gently. If they do not thus separate it is because there are other forms
of energy acting to press them together, but such external pressure will
be lessened by the rings' own reactions.

It is true that in a frictionless medium like the ether one cannot at
present see how such vortex-rings could be produced in it. Certainly not
by any such mechanical methods as are employed to make smoke-rings in
air, for the friction of the air is the condition for producing them.
However they came to be, there is implied the previous existence of the
ether and of energy in some form capable of acting upon it in a manner
radically different from any known in physical science.

There is good spectroscopic evidence that in some way elements of
different kinds are now being formed in nebulæ, for the simplest show
the presence of hydrogen alone. As they increase in complexity other
elements are added, until the spectrum exhibits all the elements we know
of. It has thus seemed likely either that most of what are called
elements are composed of molecular groupings of some fundamental
element, which by proper physical methods might be decomposed, as one
can now decompose a molecule of ammonia or sulphuric acid, or that the
elements are now being created by some extra-physical process in those
far-off regions. In either case an atom is the embodiment of energy in
such a form as to be permanent under ordinary physical circumstances,
but of which, if in any manner it should be destroyed, only the form
would be lost. The ether would remain, and the energy which was embodied
would be distributed in other ways.


THE ETHER IS ENDOWED WITH ENERGY.

The distinction between energy in matter and energy in the ether will be
apparent, on considering that both the ether and energy in some form
must be conceived as existing independent of matter; though every atom
were annihilated, the ether would remain and all the energy embodied in
the atoms would be still in existence in the ether. The atomic energy
would simply be dissolved. One can easily conceive the ether as the same
space-filling, continuous, unlimited medium, without an atom in it. On
this assumption it is clear that no form of energy with which we have to
deal in physical science would have any existence in the ether; for
every one of those forms, gravitational, thermal, electric, magnetic, or
any other--all are the results of the forms of energy in matter. If
there were no atoms, there would be no gravitation, for that is the
attraction of atoms upon each other. If there were no atoms, there could
be no atomic vibration, therefore no heat, and so on for each and all.
Nevertheless, if an atom be the embodiment of energy, there must have
been energy in the ether before any atom existed. One of the properties
of the ether is its ability to distribute energy in certain ways, but
there is no evidence that of itself it ever transforms energy. Once a
given kind of energy is in it, it does not change; hence for the
apparition of a form of energy, like the first vortex-ring, there must
have been not only energy, but some other agency capable of transforming
that energy into a permanent structure. To the best of our knowledge
to-day, the ether would be absolutely helpless. Such energy as was
active in forming atoms must be called by another name than what is
appropriate for such transformations as occur when, for instance, the
mechanical energy of a bullet is transformed into heat when the target
is struck. Behind the ether must be assumed some agency, directing and
controlling energy in a manner totally different from any agency, which
is operative in what we call physical science. Nothing short of what is
called a miracle will do--an event without a physical antecedent in any
way necessarily related to its factors, as is the fact of a stone
related to gravity or heat to an electric current.

Ether energy is an endowment instead of being an embodiment, and implies
antecedents of a super-physical kind.


12. MATTER IS AN ENERGY TRANSFORMER.

As each different kind of energy represents some specific form of
motion, and _vice versâ_, some sort of mechanism is needful for
transforming one kind into another, therefore molecular structure of
one kind or another is essential. The transformation is a mechanical
process, and matter in some particular and appropriate form is the
condition of its taking place. If heat appears, then its antecedent has
been some other form of motion acting upon the substance heated. It may
have been the mechanical motion of another mass of matter, as when a
bullet strikes a target and becomes heated; or it may be friction, as
when a car-axle heats when run without proper oiling to reduce friction;
or it may be condensation, as when tinder is ignited by condensing the
air about it; or chemical reactions, when molecular structure is changed
as in combustion, or an electrical current, which implies a dynamo and
steam-engine or water-power. If light appears, its antecedent has been
impact or friction, condensation or chemical action, and if electricity
appears the same sort of antecedents are present. Whether the one or the
other of these forms of energy is developed, depends upon what kind of a
structure the antecedent energy has acted upon. If radiant energy,
so-called, falls upon a mass of matter, what is absorbed is at once
transformed into heat or into electric or magnetic effects; _which_ one
of these depends upon the character of the mechanism upon which the
radiant energy acts, but the radiant energy itself, which consists of
ether-waves, is traceable back in every case to a mass of matter having
definite characteristic motions.

One may therefore say with certainty that every physical phenomenon is a
change in the direction, or velocity, or character, of the energy
present, and such change has been produced by matter acting as a
transformer.


THE ETHER IS A NON-TRANSFORMER.

It has already been said that the absence of friction in the ether
enables light-waves to maintain their identity for an indefinite time,
and to an indefinitely great distance. In a uniform, homogeneous
substance of any kind, any kind of energy which might be in it would
continue in it without any change. Uniformity and homogeneity imply
similarity throughout, and the necessary condition for transformation is
unlikeness. One might not look for any kind of physical phenomenon which
was not due to the presence and activity of some heterogeneity.

As a ray of light continues a ray of light so long as it exists in free
ether, so all kinds of radiations, of whatever wave-length, continue
identical until they fall upon some mechanical structure called matter.
Translatory motion continues translatory, rotary continues rotary, and
vibratory continues to be vibratory, and no transforming change can
take place in the absence of matter. The ether is helpless.


13. MATTER IS ELASTIC.

It is commonly stated that certain substances, like putty and dough, are
inelastic, while some other substances, like glass, steel, and wood, are
elastic. This quality of elasticity, as manifested in such different
degrees, depends upon molecular combinations; some of which, as in glass
and steel, are favourable for exhibiting it, while others mask it, for
the ultimate atoms of all kinds are certainly highly elastic.

The measure of elasticity in a mass of matter is the velocity with which
a wave-motion will be transmitted through it. Thus the elasticity of the
air determines the velocity of sound in it. If the air be heated, the
elasticity is increased and the sound moves faster. The rates of such
sound-conduction range from a few feet in a second to about 16,000, five
times swifter than a cannon ball. In such elastic bodies as vibrate to
and fro like the prongs of a tuning-fork, or give sounds of a definite
pitch, the rate of vibration is determined by the size and shape of the
body as well as by their elementary composition. The smaller a body is,
the higher its vibratory rate, if it be made of the same material and
the form remains the same. Thus a tuning-fork, that may be carried in
the waistcoat-pocket, may vibrate 500 times a second. If it were only
the fifty-millionth of an inch in size, but of the same material and
form, it would vibrate 30,000,000000 times a second; and if it were made
of ether, instead of steel, it would vibrate as many times faster as the
velocity of waves in the ether is greater than it is in steel, and would
be as many as 400,000000,000000 times per second. The amount of
displacement, or the amplitude of vibration, with the pocket-fork might
be no more than the hundredth of an inch, and this rate measured as
translation velocity would be but five inches per second. If the fork
were of atomic magnitude, and should swing its sides one half the
diameter of the atom, or say the hundred-millionth of an inch, the
translational velocity would be equivalent to about eighty miles a
second, or a hundred and fifty times the velocity of a cannon ball,
which may be reckoned at about 3000 feet.

That atoms really vibrate at the above rate per second is very certain,
for their vibrations produce ether-waves the length of which may be
accurately measured. When a tuning-fork vibrates 500 times a second, and
the sound travels 1100 feet in the same interval, the length of each
wave will be found by dividing the velocity in the air by the number of
vibrations, or 1100 ÷ 500 = 2.2 feet. In like manner, when one knows
the velocity and wave-length, he may compute the number of vibrations by
dividing the velocity by the wave-length. Now the velocity of the waves
called light is 186,000 miles a second, and a light-wave may be one
forty thousandth of an inch long. The atom that produces the wave must
be vibrating as many times per second as the fifth thousandth of an inch
is contained in 186,000 miles. Reducing this number to inches we have

186,000 × 5280 × 12
------------------- = 400,000,000,000,000, nearly.
      1/40,000

This shows that the atoms are minute elastic bodies that change their
form rapidly when struck. As rapid as the change is, yet the rate of
movement is only one-fifth that of a comet when near the sun, and is
therefore easily comparable with other velocities observed in masses of
matter.

These vibratory motions, due to the elasticity of the atoms, is what
constitutes heat.


THE ETHER IS ELASTIC.

The elasticity of a mass of matter is its ability to recover its
original form after that form has been distorted. There is implied that
a stress changes its shape and dimensions, which in turn implies a
limited mass and relative change of position of parts and some degree
of discontinuity. From what has been said of the ether as being
unlimited, continuous, and not made of atoms or molecules, it will be
seen how difficult, if not impossible, it is to conceive how such a
property as elasticity, as manifested in matter, can be attributed to
the ether, which is incapable of deformation, either in structure or
form, the latter being infinitely extended in every direction and
therefore formless. Nevertheless, certain forms of motion, such as
light-waves, move in it with definite velocity, quite independent of how
they originate. This velocity of 186,000 miles a second so much exceeds
any movement of a mass of matter that the motions can hardly be
compared. Thus if 400 miles per second be the swiftest speed of any mass
of matter known--that of a comet near the sun--the ether-wave moves
186,000 ÷ 400 = 465 times faster than such comet, and 900,000 times
faster than sound travels in air. It is clear that if this rate of
motion depends upon elasticity, the elasticity must be of an entirely
different type from that belonging to matter, and cannot be defined in
any such terms as are employed for matter.

If one considers gravitative phenomena, the difficulty is enormously
increased. The orbit of a planet is never an exact ellipse,
on account of the perturbations produced by the planetary
attractions--perturbations which depend upon the direction and distance
of the attracting bodies. These, however, are so well known that slight
deviations are easily noticed. If gravitative attraction took any such
appreciable time to go from one astronomical body to another as does
light, it would make very considerable differences in the paths of the
planets and the earth. Indeed, if the velocity of gravitation were less
than a million times greater than that of light, its effects would have
been discovered long ago. It is therefore considered that the velocity
of gravitation cannot be less than 186000,000000 miles per second. How
much greater it may be no one can guess. Seeing that gravitation is
ether-pressure, it does not seem probable that its velocity can be
infinite. However that may be, the ability of the ether to transmit
pressure and various disturbances, evidently depends upon properties so
different from those that enable matter to transmit disturbances that
they deserve to be called by different names. To speak of the elasticity
of the ether may serve to express the fact that energy may be
transmitted at a finite rate in it, but it can only mislead one's
thinking if he imagines the process to be similar to energy transmission
in a mass of matter. The two processes are incomparable. No other word
has been suggested, and perhaps it is not needful for most scientific
purposes that another should be adopted, but the inappropriateness of
the one word for the different phenomena has long been felt.


14. MATTER HAS DENSITY.

This quality is exhibited in two ways in matter. In the first, the
different elements in their atomic form have different masses or atomic
weights. An atom of oxygen weighs sixteen times as much as an atom of
hydrogen; that is, it has sixteen times as much matter, as determined by
weight, as the hydrogen atom has, or it takes sixteen times as many
hydrogen atoms to make a pound as it takes of oxygen atoms. This is
generally expressed by saying that oxygen has sixteen times the density
of hydrogen. In like manner, iron has fifty-six times the density, and
gold one hundred and ninety-six. The difference is one in the structure
of the atomic elements. If one imagines them to be vortex-rings, they
may differ in size, thickness, and rate of rotation; either of these
might make all the observed difference between the elements, including
their density. In the second way, density implies compactness of
molecules. Thus if a cubic foot of air be compressed until it occupies
but half a cubic foot, each cubic inch will have twice as many molecules
in it as at first. The amount of air per unit volume will have been
doubled, the weight will have been doubled, the amount of matter as
determined by its weight will have been doubled, and consequently we say
its density has been doubled.

If a bullet or a piece of iron be hammered, the molecules are compacted
closer together, and a greater number can be got into a cubic inch when
so condensed. In this sense, then, density means the number of molecules
in a unit of space, a cubic inch or cubic centimeter. There is implied
in this latter case that the molecules do not occupy all the available
space, that they may have varying degrees of closeness; in other words,
matter is discontinuous, and therefore there may be degrees in density.


THE ETHER HAS DENSITY.

It is common to have the degree of density of the ether spoken of in the
same way, and for the same reason, that its elasticity is spoken of. The
rate of transmission of a physical disturbance, as of a pressure or a
wave-motion in matter, is conditioned by its degree of density; that is,
the amount of matter per cubic inch as determined by its weight; the
greater the density the slower the rate. So if rate of speed and
elasticity be known, the density may be computed. In this way the
density of the ether has been deduced by noting the velocity of light.
The enormous velocity is supposed to prove that its density is very
small, even when compared with hydrogen. This is stated to be about
equal to that of the air at the height of two hundred and ten miles
above the surface of the earth, where the air molecules are so few that
a molecule might travel for 60,000,000 miles without coming in collision
with another molecule. In air of ordinary density, a molecule can on the
average move no further than about the two-hundred-and-fifty-thousandth
of an inch without such collision. It is plain the density of the ether
is so far removed from the density of anything we can measure, that it
is hardly comparable with such things. If, in addition, one recalls the
fact that the ether is homogeneous, that is all of one kind, and also
that it is not composed of atoms and molecules, then degree of
compactness and number of particles per cubic inch have no meaning, and
the term density, if used, can have no such meaning as it has when
applied to matter. There is no physical conception gained from the study
of matter that can be useful in thinking of it. As with elasticity, so
density is inappropriately applied to the ether, but there is no
substitute yet offered.


15. MATTER IS HEATABLE.

So long as heat was thought to be some kind of an imponderable thing,
which might retain its identity whether it were in or out of matter,
its real nature was obscured by the name given to it. An imponderable
was a mysterious something like a spirit, which was the cause of certain
phenomena in matter. Heat, light, electricity, magnetism, gravitation,
were due to such various agencies, and no one concerned himself with the
nature of one or the other. Bacon thought that heat was a brisk
agitation of the particles of substances, and Count Rumford and Sir
Humphrey Davy thought they proved that it could be nothing else, but
they convinced nobody. Mayer in Germany and Joule in England showed that
quantitative relations existed between work done and heat developed, but
not until the publication of the book called _Heat as a Mode of Motion_,
was there a change of opinion and terminology as to the nature of heat.
For twenty years after that it was common to hear the expressions heat,
and radiant heat, to distinguish between phenomena in matter and what is
now called radiant energy radiations, or simply ether-waves. Not until
the necessity arose for distinguishing between different forms of
energy, and the conditions for developing them, did it become clear to
all that a change in the form of energy implied a change in the form of
motion that embodied it. The energy called heat energy was proved to be
a vibratory motion of molecules, and what happened in the ether as a
result of such vibrations is no longer spoken of as heat, but as ether
waves. When it is remembered that the ultimate atoms are elastic bodies,
and that they will, if free, vibrate in a periodic manner when struck or
shaken in any way, just as a ball will vibrate after it is struck, it is
easy to keep in mind the distinction between the mechanical form of
motion spent in striking and the vibratory form of the motion produced
by it. The latter is called heat; no other form of motion than that is
properly called heat. It is this alone that represents temperature, the
rate and amplitude of such atomic and molecular vibrations as constitute
change, of form. Where molecules like those in a gas have some freedom
of movement between impacts, they bound away from each other with
varying velocities. The path of such motion may be long or short,
depending upon the density or compactness of the molecules, but such
changes in position are not heat for a molecule any more than the flight
of a musket ball is heat, though it may be transformed into heat on
striking the target.

This conception of heat as the rapid change in the form of atoms and
molecules, due to their elasticity, is a phenomenon peculiar to matter.
It implies a body possessing form that may be changed; elasticity, that
its changes may be periodic, and degrees of freedom that secure space
for the changes. Such a body may be heated. Its temperature will depend
upon the amplitude of such vibrations, and will be limited by the
maximum amplitude.


THE ETHER IS UNHEATABLE.

The translatory motion of a mass of matter, big or little, through the
ether, is not arrested in any degree so far as observed, but the
internal vibratory motion sets up waves in the ether, the ether absorbs
the energy, and the amplitude is continually lessened. The motion has
been transferred and transformed; transferred from matter to the ether,
and transformed from vibratory to waves travelling at the rate of
186,000 miles per second. The latter is not heat, but the result of
heat. With the ether constituted as described, such vibratory motion as
constitutes heat is impossible to it, and hence the characteristic of
heat-motion in it is impossible; it cannot therefore be heated. The
space between the earth and the sun may have any assignable amount of
energy in the form of ether waves or light, but not any temperature. One
might loosely say that the temperature of empty spaces was absolute
zero, but that would not be quite correct, for the idea of temperature
cannot properly be entertained as applicable to the ether. To say that
its temperature was absolute zero, would serve to imply that it might be
higher, which is inadmissible.

When energy has been transformed, the old name by which the energy was
called must be dropped. Ether cannot be heated.


16. MATTER IS INDESTRUCTIBLE.

This is commonly said to be one of the essential properties of matter.
All that is meant by it, however, is simply this: In no physical or
chemical process to which it has been experimentally subjected has there
been any apparent loss. The matter experimented upon may change from a
solid or liquid to a gas, or the molecular change called chemical may
result in new compounds, but the weight of the material and its atomic
constituents have not appreciably changed. That matter cannot be
annihilated is only the converse of the proposition that matter cannot
be created, which ought always to be modified by adding, by physical or
chemical processes at present known. A chemist may work with a few
grains of a substance in a beaker, or test-tube, or crucible, and after
several solutions, precipitations, fusions and dryings, may find by
final weighing that he has not lost any appreciable amount, but how much
is an appreciable amount? A fragment of matter the ten-thousandth of an
inch in diameter has too small a weight to be noted in any balance, yet
it would be made up of thousands of millions of atoms. Hence if, in the
processes to which the substance had been subjected, there had been the
total annihilation of thousands of millions of atoms, such phenomenon
would not have been discovered by weighing. Neither would it have been
discovered if there had been a similar creation or development of new
matter. All that can be asserted concerning such events is, that they
have not been discovered with our means of observation.

The alchemists sought to transform one element into another, as lead
into gold. They did not succeed. It was at length thought to be
impossible, and the attempt to do it an absurdity. Lately, however,
telescopic observation of what is going on in nebulæ, which has already
been referred to, has somewhat modified ideas of what is possible and
impossible in that direction. It is certainly possible roughly to
conceive how such a structure as a vortex-ring in the ether might be
formed. With certain polarizing apparatus it is possible to produce rays
of circularly polarized light. These are rays in which the motion is an
advancing rotation like the wire in a spiral spring. If such a line of
rotations in the ether were flexible, and the two ends should come
together, there is reason for thinking they would weld together, in
which case the structure would become a vortex-ring and be as durable as
any other. There is reason for believing, also, that somewhat similar
movements are always present in a magnetic field, and though we do not
know how to make them close up in the proper way, it does not follow
that it is impossible for them to do so.

The bearing of all this upon the problem of the transmutation of
elements is evident. No one now will venture to deny its possibility as
strongly as it was denied a generation ago. It will also lead one to be
less confident in the theory that matter is indestructible. Assuming the
vortex-ring theory of atoms to be true, if in any way such a ring could
be cut or broken, there would not remain two or more fragments of a ring
or atom. The whole would at once be dissolved into the ether. The ring
and rotary energy that made it an atom would be destroyed, but not the
substance it was made of, nor the energy which was embodied therein. For
a long time philosophers have argued, and commonsense has agreed with
them, that an atom which could not be ideally broken into two parts was
impossible, that one could at any rate think of half an atom as a real
objective possibility. This vortex-ring theory shows easily how possible
it is to-day to think what once was philosophically incredible. It shows
that metaphysical reasoning may be ever so clear and apparently
irrefragable, yet for all that it may be very unsound. The trouble does
not come so much from the logic as from the assumption upon which the
logic is founded. In this particular case the assumption was that the
ultimate particles of matter were hard, irrefragable somethings, without
necessary relations to anything else, or to energy, and irrefragable
only because no means had been found of breaking them.

The destructibility or indestructibility of the ether cannot be
considered from the same standpoint as that for matter, either ideally
or really. Not ideally, because we are utterly without any mechanical
conceptions of the substance upon which one can base either reason or
analogy; and not really, because we have no experimental evidence as to
its nature or mode of operation. If it be continuous, there are no
interspaces, and if it be illimitable there is no unfilled space
anywhere. Furthermore, one might infer that if in any way a portion of
the ether could be annihilated, what was left would at once fill up the
vacated space, so there would be no record left of what had happened.
Apparently, its destruction would be the destruction of a substance,
which is a very different thing from the destruction of a mode of
motion. In the latter, only the form of the motion need be destroyed to
completely obliterate every trace of the atom. In the former, there
would need to be the destruction of both substance and energy, for it is
certain, for reasons yet to be attended to, that the ether is saturated
with energy.

One may, without mechanical difficulties, imagine a vortex-ring
destroyed. It is quite different with the ether itself, for if it were
destroyed in the same sense as the atom of matter, it would be changed
into something else which is not ether, a proposition which assumes the
existence of another entity, the existence for which is needed only as a
mechanical antecedent for the other. The same assumption would be needed
for this entity as for the ether, namely, something out of which it was
made, and this process of assuming antecedents would be interminable.
The last one considered would have the same difficulties to meet as the
ether has now. The assumption that it was in some way and at some time
created is more rational, and therefore more probable, than that it
either created itself or that it always existed. Considered as the
underlying stratum of matter, it is clear that changes of any kind in
matter can in no way affect the quantity of ether.


17. MATTER HAS INERTIA.

The resistance that a mass of matter opposes to a change in its position
or rate and direction of movement, is called inertia. That it should
actively oppose anything has been already pointed out as reason for
denying that matter is inert, but inertia is the measure of the reaction
of a body when it is acted upon by pressure from any source tending to
disturb its condition of either rest or motion. It is the equivalent of
mass, or the amount of matter as measured by gravity, and is a fixed
quantity; for inertia is as inherent as any other quality, and belongs
to the ultimate atoms and every combination of them. It implies the
ability to absorb energy, for it requires as much energy to bring a
moving body to a standstill as was required to give it its forward
motion.

Both rotary and vibratory movements are opposed by the same property. A
grindstone, a tuning-fork, and an atom of hydrogen require, to move them
in their appropriate ways, an amount of energy proportionate to their
mass or inertia, which energy is again transformed through friction into
heat and radiated away.

One may say that inertia is the measure of the ability of a body to
transfer or transform mechanical energy. The meteorite that falls upon
the earth to-day gives, on its impact, the same amount of energy it
would have given if it had struck the earth ten thousand years ago. The
inertia of the meteor has persisted, not as energy, but as a factor of
energy. We commonly express the energy of a mass of matter by
_mv_^{2}/2, where _m_ stands for the mass and _v_ for its velocity. We
might as well, if it were as convenient, substitute inertia for mass,
and write the expression _iv_^{2}/2, for the mass, being measured by its
inertia, is only the more common and less definitive word for the same
thing. The energy of a mass of matter is, then, proportional to its
inertia, because inertia is one of its factors. Energy has often been
treated as if it were an objective thing, an entity and a unity; but
such a conception is evidently wrong, for, as has been said before, it
is a product of two factors, either of which may be changed in any
degree if the other be changed inversely in the same degree. A cannon
ball weighing 1000 pounds, and moving 100 feet per second, will have
156,000 foot-pounds of energy, but a musket ball weighing an ounce will
have the same amount when its velocity is 12,600 feet per second.
Nevertheless, another body acting upon either bullet or cannon ball,
tending to move either in some new direction, will be as efficient
while those bodies are moving at any assignable rate as when they are
quiescent, for the change in direction will depend upon the inertia of
the bodies, and that is constant.

The common theory of an inert body is one that is wholly passive, having
no power of itself to move or do anything, except as some agency outside
itself compels it to move in one way or another, and thus endows it with
energy. Thus a stone or an iron nail are thought to be inert bodies in
that sense, and it is true that either of them will remain still in one
place for an indefinite time and move from it only when some external
agency gives them impulse and direction. Still it is known that such
bodies will roll down hill if they will not roll up, and each of them
has itself as much to do with the down-hill movement as the earth has;
that is, it attracts the earth as much as the earth attracts it. If one
could magnify the structure of a body until the molecules became
individually visible, every one of them would be seen to be in intense
activity, changing its form and relative position an enormous number of
times per second in undirected ways. No two such molecules move in the
same way at the same time, and as all the molecules cohere together,
their motions in different directions balance each other, so that the
body as a whole does not change its position, not because there is no
moving agency in itself, but because the individual movements are
scattering, and not in a common direction. An army may remain in one
place for a long time. To one at a distance it is quiescent, inert. To
one in the camp there is abundant sign of activity, but the movements
are individual movements, some in one direction and some in another, and
often changing. The same army on the march has the same energy, the same
rate of individual movement; but all have a common direction, it moves
as a whole body into new territory. So with the molecules of matter. In
large masses they appear to be inert, and to do nothing, and to be
capable of doing nothing. That is only due to the fact that their energy
is undirected, not that they can do nothing. The inference that if
quiescent bodies do not act in particular ways they are inert, and
cannot act in any kind of a way, is a wrong inference. An illustration
may perhaps make this point plainer. A lump of coal will be still as
long as anything if it be undisturbed. Indeed, it has thus lain in a
coal-bed for millions of years probably, but if coal be placed where it
can combine with oxygen, it forthwith does so, and during the process
yields a large amount of energy in the shape of heat. One pound of coal
in this way gives out 14,000 heat units, which is the equivalent of
11,000,000 foot-pounds of work, and if it could be all utilized would
furnish a horse-power for five and a half hours. Can any inert body
weighing a pound furnish a horse-power for half a day? And can a body
give out what it has not got? Are gunpowder and nitro-glycerine inert?
Are bread and butter and foods in general inert because they will not
push and pull as a man or a horse may? All have energy, which is
available in certain ways and not in others, and whatever possesses
energy available in any way is not an ideally inert body. Lastly, how
many inert bodies together will it take to make an active body? If the
question be absurd, then all the phenomena witnessed in bodies, large or
small, are due to the fact that the atoms are not inert, but are
immensely energetic, and their inertia is the measure of their rates of
exchanging energy.


THE ETHER IS CONDITIONALLY POSSESSED OF INERTIA.

A moving mass of matter is brought to rest by friction, because it
imparts its motion at some rate to the body it is in contact with.
Generally the energy is transformed into heat, but sometimes it appears
as electrification. Friction is only possible because one or both of the
bodies possess inertia. That a body may move in the ether for an
indefinite time without losing its velocity has been stated as a reason
for believing the ether to be frictionless. If it be frictionless, then
it is without inertia, else the energy of the earth and of a ray of
light would be frittered away. A ray of light can only be transformed
when it falls upon molecules which may be heated by it. As the ether
cannot be heated and cannot transform translational energy, it is
without inertia for _such_ a form of motion and its embodied energy.

It is not thus with other forms of energy than the translational. Atomic
and molecular vibrations are so related to the ether that they are
transformed into waves, which are conducted away at a definite rate.
This shows that such property of inertia as is possessed by the ether is
selective and not like that of matter, which is equally "inertiative"
under all conditions. Similarly with electric and magnetic phenomena, it
is capable of transforming the energy which may reside as stress in the
ether, and other bodies moving in the space so affected meet with
frictional resistance, for they become heated if the motion be
maintained. On the other hand, there is no evidence that the body which
produced the electric or magnetic stress suffers any degree of friction
on moving in precisely the same space. A bar magnet rotating on its
longitudinal axis does not disturb its own field, but a piece of iron
revolving near the magnet will not only become heated, but will heat the
stationary magnet. Much experimental work has been done to discover, if
possible, the relation of a magnet to its ether field. As the latter is
not disturbed by the rotation of the magnet, it has been concluded that
the field does not rotate; but as every molecule in the magnet has its
own field independent of all the rest, it is mechanically probable that
each such field does vary in the rotation, but among the thousands of
millions of such fields the average strength of the field does not vary
within measurable limits. Another consideration is that the magnetic
field itself, when moved in space, suffers no frictional resistance.
There is no magnetic energy wasted through ether inertia. These
phenomena show that whether the ether exhibits the quality called
inertia depends upon the kind of motion it has.


18. MATTER IS MAGNETIC.

The ordinary phenomenon of magnetism is shown by bringing a piece of
iron into the neighbourhood of a so-called magnet, where it is attracted
by the latter, and if free to move will go to and cling to the magnet. A
delicately suspended magnetic needle will be affected appreciably by a
strong magnet at the distance of several hundred feet. As the strength
of such action varies inversely as the square of the distance from the
magnet, it is evident there can be no absolute boundary to it. At a
distance from an ordinary magnet it becomes too weak to be detected by
our methods, not that there is a limit to it. It is customary to think
of iron as being peculiarly endowed with magnetic quality, but all kinds
of matter possess it in some degree. Wood, stone, paper, oats, sulphur,
and all the rest, are attracted by a magnet, and will stick to it if the
magnet be a strong one. Whether a piece of iron itself exhibits the
property depends upon its temperature, for near 700 degrees it becomes
as magnetically indifferent as a piece of copper at ordinary
temperature. Oxygen, too, at 200 degrees below the zero of Centigrade
adheres to a magnet like iron.

In this as in so many other particulars, how a piece of matter behaves
depends upon its temperature, not that the essential qualities are
modified in any degree, but temperature interferes with atomic
arrangement and aggregation, and so disguises their phenomena.

As every kind of matter is thus affected by a magnet, the manifestations
differing but in degree, it follows that all kinds of atoms--all the
elements--are magnetic. An inherent property in them, as much so as
gravitation or inertia; apparently a quality depending upon the
structure of the atoms themselves, in the same sense as gravitation is
thus dependent, as it is not a quality of the ether.

An atom must, then, be thought of as having polarity, different
qualities on the two sides, and possessing a magnetic field as extensive
as space itself. The magnetic field is the stress or pressure in the
ether produced by the magnetic body. This ether pressure produced by a
magnet may be as great as a ton per square inch. It is this pressure
that holds an armature to the magnet. As heat is a molecular condition
of vibration, and radiant energy the result of it, so is magnetism a
property of molecules, and the magnetic field the temporary condition in
the ether, which depends upon the presence of a magnetic body. We no
longer speak of the wave-motion in the ether which results from heat, as
heat, but call it radiation, or ether waves, and for a like reason the
magnetic field ought not to be called magnetism.


THE ETHER IS NON-MAGNETIC.

A magnetic field manifests itself in a way that implies that the ether
structure, if it may be said to have any, is deformed--deformed in such
a sense that another magnet in it tends to set itself in the plane of
the stress; that is, the magnet is twisted into a new position to
accommodate itself to the condition of the medium about it. The new
position is the result of the reaction of the ether upon the magnet and
ether pressure acting at right angles to the body that produced the
stress. Such an action is so anomalous as to suggest the propriety of
modifying the so-called third law of motion, viz., action and reaction
are equal and opposite, adding that sometimes action and reaction are at
right angles.

There is no condition or property exhibited by the ether itself which
shows it to have any such characteristic as attraction, repulsion, or
differences in stress, except where its condition is modified by the
activities of matter in some way. The ether itself is not attracted or
repelled by a magnet; that is, it is not a magnetic body in any such
sense as matter in any of its forms is, and therefore cannot properly be
called magnetic.

It has been a mechanical puzzle to understand how the vibratory motions
called heat could set up light waves in the ether seeing that there is
an absence of friction in the latter. In the endeavour to conceive it,
the origin of sound-waves has been in mind, where longitudinal air-waves
are produced by the vibrations of a sounding body, and molecular impact
is the antecedent of the waves. The analogy does not apply. The
following exposition may be helpful in grasping the idea of such
transformation and change of energy from matter to the ether.

Consider a straight bar permanent magnet to be held in the hand. It has
its north and south poles and its field, the latter extending in every
direction to an indefinite distance. The field is to be considered as
ether stress of such a sort as to tend to set other magnets in it in new
positions. If at a distance of ten feet there were a delicately-poised
magnet needle, every change in the position of the magnet held in the
hand would bring about a change in the position of the needle. If the
position of the hand magnet were completely reversed, so the south pole
faced where the north pole faced before, the field would have been
completely reversed, and the poised needle would have been pushed by the
field into an opposite position. If the needle were a hundred feet away,
the change would have been the same except in amount. The same might be
said if the two were a mile apart, or the distance of the moon or any
other distance, for there is no limit to an ether magnetic field.
Suppose the hand magnet to have its direction completely reversed once
in a second. The whole field, and the direction of the stress, would
necessarily be reversed as often. But this kind of change in stress is
known by experiment to travel with the speed of light, 186,000 miles a
second; the disturbance due to the change of position of the magnet will
therefore be felt in some degree throughout space. In a second and a
third of a second it will have reached the moon, and a magnet there will
be in some measure affected by it. If there were an observer there with
a delicate-enough magnet, he could be witness to its changes once a
second for the same reason one in the room could. The only difference
would be one of amount of swing. It is therefore theoretically possible
to signal to the moon with a swinging magnet. Suppose again that the
magnet should be swung twice a second, there would be formed two waves,
each one half as long as the first. If it should swing ten times a
second, then the waves would be one-tenth of 186,000 miles long. If in
some mechanical way it could be rotated 186,000 times a second, the wave
would be but one mile long. Artificial ways have been invented for
changing this magnet field as many as 100 million times a second, and
the corresponding wave is less than a foot long. The shape of a magnet
does not necessarily make it weaker or stronger as a magnet, but if the
poles are near together the magnetic field is denser between them than
when they are separated. The ether stress is differently distributed for
every change in the relative positions of the poles.

A common U-magnet, if struck, will vibrate like a tuning-fork, and gives
out a definite pitch. Its poles swing towards and away from each other
at uniform rates, and the pitch of the magnet will depend upon its size,
thickness, and the material it is made of.

Let ten or fifteen ohms of any convenient-sized wire be wound upon the
bend of a commercial U-magnet. Let this wire be connected to a telephone
in its circuit. When the magnet is made to sound like a tuning-fork, the
pitch will be reproduced in the telephone very loudly. If another magnet
with a different pitch be allowed to vibrate near the former, the pitch
of the vibrating body will be heard in the telephone, and these show
that the changing magnetic field reacts upon the quiescent magnet, and
compels the latter to vibrate at the same rate. The action is an ether
action, the waves are ether waves, but they are relatively very long. If
the magnet makes 500 vibrations a second, the waves will be 372 miles
long, the number of times 500 is contained in 186,000 miles. Imagine the
magnet to become smaller and smaller until it was the size of an atom,
the one-fifty-millionth of an inch. Its vibratory rate would be
proportionally increased, and changes in its form will still bring about
changes in its magnetic field. But its magnetic field is practically
limitless, and the number of vibrations per second is to be reckoned
as millions of millions; the waves are correspondingly short,
small fractions of an inch. When they are as short as the
one-thirty-seven-thousandth of an inch, they are capable of affecting
the retina of the eye, and then are said to be visible as red light. If
the vibratory rate be still higher, and the corresponding waves be no
more than one-sixty-thousandth of an inch long, they affect the retina
as violet light, and between these limits there are all the waves that
produce a complete spectrum. The atoms, then, shake the ether in this
way because they all have a magnetic hold upon the ether, so that any
disturbance of their own magnetism, such as necessarily comes when they
collide, reacts upon the ether for the same reason that a large magnet
acts thus upon it when its poles approach and recede from each other. It
is not a phenomenon of mechanical impact or frictional resistance, since
neither are possible in the ether.


19. MATTER EXISTS IN SEVERAL STATES.

Molecular cohesion exists between very wide ranges. When strong, so if
one part of a body is moved the whole is moved in the same way, without
breaking continuity or the relative positions of the molecules, we call
the body a solid. In a liquid, cohesion is greatly reduced, and any part
of it may be deformed without materially changing the form of the rest.
The molecules are free to move about each other, and there is no
definite position which any need assume or keep. With gases, the
molecules are without any cohesion, each one is independent of every
other one, collides with and bounds away from others as free elastic
particles do. Between impacts it moves in what is called its free path,
which may be long or short as the density of the gas be less or greater.

These differing degrees of cohesion depend upon temperature, for if the
densest and hardest substances are sufficiently heated they will become
gaseous. This is only another way of saying that the states of matter
depend upon the amount of molecular energy present. Solid ice becomes
water by the application of heat. More heat reduces it to steam; still
more decomposes the steam molecules into oxygen and hydrogen molecules;
and lastly, still more heat will decompose these molecules into their
atomic state, complete dissociation. On cooling, the process of
reduction will be reversed until ice has been formed again.

Cohesive strength in solids is increased by reduction of temperature,
and metallic rods become stronger the colder they are.

No distinction is now made between cohesion and chemical affinity, and
yet at low temperatures chemical action will not take place, which
phenomenon shows there is a distinction between molecular cohesion and
molecular structure. In molecular structure, as determined by chemical
activity, the molecules and atoms are arranged in definite ways which
depend upon the rate of vibrations of the components. The atoms are set
in definite positions to constitute a given molecule. But atoms or
molecules may cohere for other reasons, gravitative or magnetic, and
relative positions would be immaterial. In the absence of temperature, a
solid body would be solider and stronger than ever, while a gaseous mass
would probably fall by gravity to the floor of the containing vessel
like so much dust. The molecular structure might not be changed, for
there would be no agency to act upon it in a disturbing way.


THE ETHER HAS NO CORRESPONDING STATES.

Degrees of density have already been excluded, and the homogeneity and
continuity of the ether would also exclude the possibility of different
states at all comparable with such as belong to matter. As for cohesion,
it is doubtful if the term ought to be applied to such a substance. The
word itself seems to imply possible separateness, and if the ether be a
single indivisible substance, its cohesion must be infinite and is
therefore not a matter of degree. The ether has sometimes been
considered as an elastic solid, but such solidity is comparable with
nothing we call solid in matter, and the word has to be defined in a
special sense in order that its use may be tolerated at all. In addition
to this, some of the phenomena exhibited by it, such as diffraction and
double refraction, are quite incompatible with the theory that the ether
is an elastic solid. The reasons why it cannot be considered as a liquid
or gas have been considered previously.

The expression _states of matter_ cannot be applied to the ether in any
such sense as it is applied to matter, but there is one sense when
possibly it may be considered applicable. Let it be granted that an atom
is a vortex-ring of ether in the ether, then the state of being in ring
rotation would suffice to differentiate that part of the ether from the
rest, and give to it a degree of individuality not possessed by the
rest; and such an atom might be called a state of ether. In like manner,
if other forms of motion, such as transverse waves, circular and
elliptical spirals, or others, exist in the ether, then such movements
give special character to the part thus active, and it would be proper
to speak of such states of the ether, but even thus the word would not
be used in the same sense as it is used when one speaks of the states of
matter as being solid, liquid, and gaseous.


20. SOLID MATTER CAN EXPERIENCE A SHEARING STRESS, LIQUIDS AND GASES
CANNOT.

A sliding stress applied to a solid deforms it to a degree which depends
upon the stress and the degree of rigidity preserved by the body. Thus
if the hand be placed upon a closed book lying on the table, and
pressure be so applied as to move the upper side of the book but not the
lower, the book is said to be subject to a shearing stress. If the
pressing hand has a twisting motion, the book will be warped. Any solid
may be thus sheared or warped, but neither liquids nor gases can be so
affected. Molecular cohesion makes it possible in the one, and the lack
of it, impossible in the others. The solid can maintain such a
deformation indefinitely long, if the pressure does not rupture its
molecular structure.


THE ETHER CAN MAINTAIN A SHEARING STRESS.

The phenomena in a magnetic field show that the stress is of such a sort
as to twist into a new directional position the body upon which it acts
as exhibited by a magnetic needle, also as indicated by the transverse
vibrations of the ether waves, and again by the twist given to plane
polarized light when moving through a magnetic field. These are all
interpreted as indicative of the direction of ether stress, as being
similar to a shearing stress in solid matter. The fact has been adduced
to show the ether to be a solid, but such a phenomenon is certainly
incompatible with a liquid or gaseous ether. This kind of stress is
maintained indefinitely about a permanent magnet, and the mechanical
pressure which may result from it is a measure of the strength of the
magnetic field, and may exceed a thousand pounds per square inch.


21. OTHER PROPERTIES OF MATTER.

There are many secondary qualities exhibited by matter in some of its
forms, such as hardness, brittleness, malleability, colour, etc., and
the same ultimate element may exhibit itself in the most diverse ways,
as is the case with carbon, which exists as lamp-black, charcoal,
graphite, jet, anthracite and diamond, ranging from the softest to the
hardest of known bodies. Then it may be black or colourless. Gold is
yellow, copper red, silver white, chlorine green, iodine purple. The
only significance any or all of such qualities have for us here is that
the ether exhibits none of them. There is neither hardness nor
brittleness, nor colour, nor any approach to any of the characteristics
for the identification of elementary matter.


22. SENSATION DEPENDS UPON MATTER.

However great the mystery of the relation of body to mind, it is quite
true that the nervous system is the mechanism by and through which all
sensation comes, and that in our experience in the absence of nerves
there is neither sensation nor consciousness. The nerves themselves are
but complex chemical structures; their molecular constitution is said to
embrace as many as 20,000 atoms, chiefly carbon, hydrogen, oxygen, and
nitrogen. There must be continuity of this structure too, for to sever a
nerve is to paralyze all beyond. If all knowledge comes through
experience, and all experience comes through the nervous system, the
possibilities depend upon the mechanism each one is provided with for
absorbing from his environment, what energies there are that can act
upon the nerves. Touch, taste, and smell imply contact, sound has
greater range, and sight has the immensity of the universe for its
field. The most distant but visible star acts through the optic nerve to
present itself to consciousness. It is not the ego that looks out
through the eyes, but it is the universe that pours in upon the ego.

Again, all the known agencies that act upon the nerves, whether for
touch or sound or sight, imply matter in some of its forms and
activities, to adapt the energy to the nervous system. The mechanism
for the perception of light is complicated. The light acts upon a
sensitive surface where molecular structure is broken up, and this
disturbance is in the presence of nerve terminals, and the sensation is
not in the eye but in the sensorium. In like manner for all the rest; so
one may fairly say that matter is the condition for sensation, and in
its absence there would be nothing we call sensation.


THE ETHER IS INSENSIBLE TO NERVES.

The ether is in great contrast with matter in this particular. There is
no evidence that in any direct way it acts upon any part of the nervous
system, or upon the mind. It is probable that this lack of relation
between the ether and the nervous system was the chief reason why its
discovery was so long delayed, as the mechanical necessities for it even
now are felt only by such as recognize continuity as a condition for the
transmission of energy of whatever kind it may be. Action at a distance
contradicts all experience, is philosophically incredible, and is
repudiated by every one who once perceives that energy has two
factors--substance and motion.

The table given below presents a list of twenty-two of the known
properties of matter contrasted with those exhibited by the ether. In
none of them are the properties of the two identical, and in most of
them what is true for one is not true for the other. They are not simply
different, they are incomparable.

From the necessities of the case, as knowledge has been acquired and
terminology became essential for making distinctions, the ether has been
described in terms applicable to matter, hence such terms as mass,
solidity, elasticity, density, rigidity, etc., which have a definite
meaning and convey definite mechanical conceptions when applied to
matter, but have no corresponding meaning and convey no such mechanical
conceptions when applied to the ether. It is certain that they are
inappropriate, and that the ether and its properties cannot be described
in terms applicable to matter. Mathematical considerations derived from
the study of matter have no advantage, and are not likely to lead us to
a knowledge of the ether.

Only a few have perceived the inconsistency of thinking of the two in
the same terms. In his _Grammar of Science_, Prof. Karl Pearson says,
"We find that our sense-impressions of hardness, weight, colour,
temperature, cohesion, and chemical constitution, may all be described
by the aid of the motions of a single medium, which itself is conceived
to have no hardness, weight, colour, temperature, nor indeed elasticity
of the ordinary conceptual type."

None of the properties of the ether are such as one would or could have
predicted if he had had all the knowledge possessed by mankind. Every
phenomenon in it is a surprise to us, because it does not follow the
laws which experience has enabled us to formulate for matter. A
substance which has none of the phenomenal properties of matter, and is
not subject to the known laws of matter, ought not to be called matter.
Ether phenomena and matter phenomena belong to different categories, and
the ends of science will not be conserved by confusing them, as is done
when the same terminology is employed for both.

There are other properties belonging to the ether more wonderful, if
possible, than those already mentioned. Its ability to maintain enormous
stresses of various kinds without the slightest evidence of
interference. There is the gravitational stress, a direct pull between
two masses of matter. Between two molecules it is immeasurably small
even when close together, but the prodigious number of them in a bullet
brings the action into the field of observation, while between such
bodies as the earth and moon or sun, the quantity reaches an astonishing
figure. Thus if the gravitative tension due to the gravitative
attraction of the earth and moon were to be replaced by steel wires
connecting the two bodies to prevent the moon from leaving its orbit,
there would be needed four number ten steel wires to every square inch
upon the earth, and these would be strained nearly to the breaking
point. Yet this stress is not only endured continually by this pliant,
impalpable, transparent medium, but other bodies can move through the
same space apparently as freely as if it were entirely free. In addition
to this, the stress from the sun and the more variable stresses from the
planets are all endured by the same medium in the same space and
apparently a thousand or a million times more would not make the
slightest difference. Rupture is impossible.

Electric and magnetic stresses, acting parallel or at right angles to
the other, exist in the same space and to indefinite degrees, neither
modifying the direction nor amount of either of the others.

These various stresses have been computed to represent energy, which if
it could be utilized, each cubic inch of space would yield five hundred
horse-power. It shows what a store-house of energy the ether is. If
every particle of matter were to be instantly annihilated, the universe
of ether would still have an inexpressible amount of energy left. To
draw at will directly from this inexhaustible supply, and utilize it for
the needs of mankind, is not a forlorn hope.

The accompanying table presents these contrasting properties for
convenient inspection.


CONTRASTED PROPERTIES OF MATTER AND THE ETHER.

         MATTER.                         ETHER.

 1. Discontinuous               Continuous
 2. Limited                     Unlimited
 3. Heterogeneous               Homogeneous
 4. Atomic                      Non-atomic
 5. Definite structure          Structureless
 6. Gravitative                 Gravitationless
 7. Frictionable                Frictionless
 8. Æolotropic                  Isotropic
 9. Chemically selective          ----
10. Harmonically related          ----
11. Energy embodied             Energy endowed
12. Energy transformer          Non-transformer
13. Elastic                     Elastic?
14. Density                     Density?
15. Heatable                    Unheatable
16. Indestructible?             Indestructible
17. Inertiative                 Inertiative conditionally
18. Magnetic                      ----
19. Variable states               ----
20. Subject to shearing stress
     in solid                   Shearing stress maintained
21. Has Secondary qualities       ----
22. Sensation depends upon      Insensible to nerves




CHAPTER III

Antecedents of Electricity--Nature of what is
    transformed--Series of transformations for the
    production of light--Positive and negative
    Electricity--Positive and negative twists--Rotations
    about a wire--Rotation of an arc--Ether a
    non-conductor--Electro-magnetic waves--Induction
    and inductive action--Ether stress and atomic
    position--Nature of an electric current--Electricity
    a condition, not an entity.


So far as we have knowledge to-day, the only factors we have to consider
in explaining physical phenomena are: (1) Ordinary matter, such as
constitutes the substance of the earth, and the heavenly bodies; (2) the
ether, which is omnipresent; and (3) the various forms of motion, which
are mutually transformable in matter, and some of which, but not all,
are transformable into ether forms. For instance, the translatory motion
of a mass of matter can be imparted to another mass by simple impact,
but translatory motion cannot be imparted to the ether, and, for that
reason, a body moving in it is not subject to friction, and continues
to move on with velocity undiminished for an indefinite time; but the
vibratory motion which constitutes heat is transformable into
wave-motion in the ether, and is transmitted away with the speed of
light. The kind of motion which is thus transformed is not even a
to-and-fro swing of an atom, or molecule, like the swing of a pendulum
bob, but that due to a change of form of the atoms within the molecule,
otherwise there could be no such thing as spectrum analysis. Vibratory
motion of the matter becomes undulatory motion in the ether. The
vibratory motion we call heat; the wave-motion we call sometimes radiant
energy, sometimes light. Neither of these terms is a good one, but we
now have no others.

It is conceded that it is not proper to speak of the wave-motion in the
ether as _heat_; it is also admitted that the ether is not heated by the
presence of the wave--or, in other words, the temperature of the ether
is absolute zero. Matter only can be heated. But the ether waves can
heat other matter they may fall on; so there are three steps in the
process and two transformations--(1) vibrating matter; (2) waves in the
ether; (3) vibration in other matter. Energy has been transferred
indirectly. What is important to bear in mind is, that when a form of
energy in matter is transformed in any manner so as to lose its
characteristics, it is not proper to call it by the same name after as
before, and this we do in all cases when the transformation is from one
kind in matter to another kind in matter. Thus, when a bullet is shot
against a target, before it strikes it has what we call mechanical
energy, and we measure that in foot-pounds; after it has struck the
target, the transformation is into heat, and this has its mechanical
equivalent, but is not called mechanical energy, nor are the motions
which embody it similar. The mechanical ideas in these phenomena are
easy to grasp. They apply to the phenomena of the mechanics of large and
small bodies, to sound, to heat, and to light, as ordinarily considered,
but they have not been applied to electric phenomena, as they evidently
should be, unless it be held that such phenomena are not related to
ordinary phenomena, as the latter are to one another.

When we would give a complete explanation of the phenomena exhibited by,
say, a heated body, we need to inquire as to the antecedents of the
manifestation, and also its consequents. Where and how did it get its
heat? Where and how did it lose it? When we know every step of those
processes, we know all there is to learn about them. Let us undertake
the same thing for some electrical phenomena.

First, under what circumstances do electrical phenomena arise?

(1) _Mechanical_, as when two different kinds of matter are subject to
friction.

(2) _Thermal_, as when two substances in molecular contact are heated at
the junction.

(3) _Magnetic_, as when any conductor is in a changing magnetic field.

(4) _Chemical_, as when a metal is being dissolved in any solution.

(5) _Physiological_, as when a muscle contracts.

[Illustration: FIG. 5.--Frictional electrical machine.]

Each of these has several varieties, and changes may be rung on
combinations of them, as when mechanical and magnetic conditions
interact.

(1) In the first case, ordinary mechanical or translational energy is
spent as friction, an amount measurable in foot-pounds, and the factors
we know, a pressure into a distance. If the surface be of the same kind
of molecules, the whole energy is spent as heat, and is presently
radiated away. If the surfaces are of unlike molecules, the product is a
compound one, part heat, part electrical. What we have turned into the
machine we know to be a particular mode of motion. We have not changed
the amount of matter involved; indeed, we assume, without specifying and
without controversy, that matter is itself indestructible, and the
product, whether it be of one kind or another, can only be some form of
motion. Whether we can describe it or not is immaterial; but if we agree
that heat is vibratory molecular motion, and there be any other kind of
a product than heat, it too must also be some other form of motion. So
if one is to form a conception of the mechanical origin of electricity,
this is the only one he can have--transformed motion.

[Illustration: FIG. 6.--Thermo-pile.]

[Illustration: FIG. 7.--Dynamo.]

(2) When heat is the antecedent of electricity, as in the thermo-pile,
that which is turned into the pile we know to be molecular motion of a
definite kind. That which comes out of it must be some equivalent
motion, and if all that went in were transformed, then all that came out
would be transformed, call it by what name we will and let its amount be
what it may.

(3) When a conductor is moved in a magnetic field, the energy spent is
measurable in foot-pounds, as before, a pressure into a distance. The
energy appears in a new form, but the quantity of matter being
unchanged, the only changeable factor is the kind of motion, and that
the motion is molecular is evident, for the molecules are heated.
Mechanical or mass motion is the antecedent, molecular heat motion is
the consequent, and the way we know there has been some intermediate
form is, that heat is not conducted at the rate which is observed in
such a case. Call it by what name one will, some form of motion has been
intermediate between the antecedent and the consequent, else we have
some other factor of energy to reckon with than ether, matter and
motion.

(4) In a galvanic battery, the source of electricity is chemical action;
but what is chemical action? Simply an exchange of the constituents of
molecules--a change which involves exchange of energy. Molecules capable
of doing chemical work are loaded with energy. The chemical products of
battery action are molecules of different constitution, with smaller
amounts of energy as measured in calorics or heat units. If the results
of the chemical reaction be prevented from escaping, by confining them
to the cell itself, the whole energy appears as heat and raises the
temperature of the cell. If a so-called circuit be provided, the energy
is distributed through it, and less heat is spent in the cell, but
whether it be in one place or another, the mass of matter involved is
not changed, and the variable factor is the motion, the same as in the
other cases. The mechanical conceptions appropriate are the
transformation of one kind of motion into another kind by the mechanical
conditions provided.

[Illustration: FIG. 8.--Galvanic Battery.]

(5) Physiological antecedents of electricity are exemplified by the
structure and mode of operation of certain muscles (Fig. 9, _a_) in the
torpedo and other electrical animals. The mechanical contraction of them
results in an electrical excitation, and, if a proper circuit be
provided, in an electric current. The energy of a muscle is derived from
food, which is itself but a molecular compound loaded with energy of a
kind available for muscular transformation. Bread-and-butter has more
available energy, pound for pound, than has coal, and can be substituted
for coal for running an engine. It is not used, because it costs so much
more. There is nothing different, so far as the factors of energy go,
between the food of an animal and the food of an engine. What becomes of
the energy depends upon the kind of structure it acts on. It may be
changed into translatory, and the whole body moves in one direction; or
into molecular, and then appears as heat or electrical energy.

If one confines his attention to the only variable factor in the energy
in all these cases, and traces out in each just what happens, he will
have only motions of one sort or another, at one rate or another, and
there is nothing mysterious which enters into the processes.

We will turn now to the mode in which electricity manifests itself, and
what it can do. It may be well to point out at the outset what has
occasionally been stated, but which has not received the philosophical
attention it deserves--namely, that electrical phenomena are reversible;
that is, any kind of a physical process which is capable of producing
electricity, electricity is itself able to produce. Thus to name a few:
If mechanical motion develops electricity, electricity will produce
mechanical motion; the movement of a pith ball and an electric motor are
examples. If chemical action can produce it, it will produce chemical
action, as in the decomposition of water and electro-plating. As heat
may be its antecedent, so will it produce heat. If magnetism be an
antecedent factor, magnetism may be its product. What is called
induction may give rise to it in an adjacent conductor, and, likewise,
induction may be its effect.

[Illustration: FIG. 9.--Torpedo.]

[Illustration: FIG. 10.--Dynamo and Motor.]

Let us suppose ourselves to be in a building in which a steam-engine is
at work. There is fuel, the furnace, the boiler, the pipes, the engine
with its fly-wheel turning. The fuel burns in the furnace, the water is
superheated in the boiler, the steam is directed by the pipes, the
piston is moved by the steam pressure, and the fly-wheel rotates
because of proper mechanism between it and the piston. No one who has
given attention to the successive steps in the process is so puzzled as
to feel the need of inventing a particular force, or a new kind of
matter, or any agency, at any stage of the process, different from the
simple mechanical ones represented by a push or a pull. Even if he
cannot see clearly how heat can produce a push, he does not venture to
assume a genii to do the work, but for the time is content with saying
that if he starts with motion in the furnace and stops with the motion
of the fly-wheel, any assumption of any other factor than some form of
motion between the two would be gratuitous. He can truthfully say that
he understands the _nature_ of that which goes on between the furnace
and the wheel; that it is some sort of motion, the particular kind of
which he might make out at his leisure.

Suppose once more that, across the road from an engine-house, there was
another building, where all sorts of machines--lathes, planers, drills,
etc.--were running, but that the source of the power for all this was
out of sight, and that one could see no connection between this and the
engine on the other side of the street. Would one need to suppose there
was anything mysterious between the two--a force, a fluid, an immaterial
something? This question is put on the supposition that one should not
be aware of the shaft that might be between the two buildings, and that
it was not obvious on simple inspection how the machines got their
motions from the engine. No one would be puzzled because he did not know
just what the intervening mechanism might be. If the boiler were in the
one building, and the engine in the other with the machines, he could
see nothing moving between them, even if the steam-pipes were of glass.
If matter of any kind were moving, he could not see it there. He would
say there _must_ be something moving, or pressure could not be
transferred from one place to the other.

Substitute for the furnace and boiler a galvanic battery or a dynamo;
for the machines of the shop, one or more motors with suitable wire
connections. When the dynamo goes the motors go; when the dynamo stops
the motors stop; nothing can be seen to be turning or moving in any way
between them. Is there any necessity for assuming a mysterious agency,
or a force of a _nature_ different from the visible ones at the two ends
of the line? Is it not certain that the question is, How does the motion
get from one to the other, whether there be a wire or not? If there be a
wire, it is plain that there is motion in it, for it is heated its whole
length, and heat is known to be a mode of motion, and every molecule
which is thus heated must have had some antecedent motions. Whether it
be defined or not, and whether it be called by one name or another, are
quite immaterial, if one is concerned only with the _nature_ of the
action, whether it be matter or ether, or motion or abracadabra.

Once more: suppose we have a series of active machines. (Fig. 11.) An
arc lamp, radiating light-waves, gets its energy from the wire which is
heated, which in turn gets its energy from the electric current; that
from a dynamo, the dynamo from a steam-engine; that from a furnace and
the chemical actions going on in it. Let us call the chemical actions A,
the furnace B, the engine C, the dynamo D, the electric lamp E, the
ether waves F. (Fig. 12.)

[Illustration: FIG. 11.]

The product of the chemical action of the coal is molecular motion,
called heat in the furnace. The product of the heat is mechanical motion
in the engine. The product of the mechanical motion is electricity in
the dynamo. The product of the electric current in the lamp is
light-waves in the ether. No one hesitates for an instant to speak of
the heat as being molecular motion, nor of the motions of the engine as
being mechanical; but when we come to the product of the dynamo, which
we call electricity, behold, nearly every one says, not that he does not
know what it is, but that no one knows! Does any one venture to say he
does not know what heat is, because he cannot describe in detail just
what goes on in a heated body, as it might be described by one who saw
with a microscope the movements of the molecules? Let us go back for a
moment to the proposition stated early in this book, namely, that if any
body of any magnitude moves, it is because some other body in motion and
in contact with it has imparted its motion by mechanical pressure.
Therefore, the ether waves at F (Fig. 11) imply continuous motions of
some sort from A to F. That they are all motions of ordinary matter from
A to E is obvious, because continuous matter is essential for the
maintenance of the actions. At E the motions are handed over to the
ether, and they are radiated away as light-waves.

[Illustration: FIG. 12.]

[Illustration: FIG. 13.]

A puzzling electrical phenomenon has been what has been called its
duality-states, which are spoken of as positive and negative. Thus, we
speak of the positive plate of a battery and the negative pole of a
dynamo; and another troublesome condition to idealize has been, how it
could be that, in an electric circuit, there could be as much energy at
the most remote part as at the source. But, if one will take a limp
rope, 8 or 10 feet long, tie its ends together, and then begin to twist
it at any point, he will see the twist move in a right-handed spiral on
the one hand, and in a left-handed spiral on the other, and each may be
traced quite round the circuit; so there will be as much twist, as much
motion, and as much energy in one part of the rope as in any other; and
if one chooses to call the right-handed twist positive, and the
left-handed twist negative, he will have the mechanical phenomenon of
energy-distribution and the terminology, analogous to what they are in
an electric conductor. (Fig. 13.) Are the cases more dissimilar than the
mechanical analogy would make them seem to be?

Are there any phenomena which imply that rotation is going on in an
electric conductor? There are. An electric arc, which is a current in
the air, and is, therefore, less constrained than it is in a conductor,
rotates. Especially marked is this when in front of the pole of a
magnet; but the rotation may be noticed in an ordinary arc by looking at
it with a stroboscope disk, rotated so as to make the light to the eye
intermittent at the rate of four or five hundred per second. A ray of
plane polarized light, parallel with a wire conveying a current, has its
plane of vibration twisted to the right or left, as the current goes
one way or the other through the wire, and to a degree that depends upon
the distance it travels; not only so, but if the ray be sent, by
reflection, back through the same field, it is twisted as much more--a
phenomenon which convinces one that rotation is going on in the space
through which the ray travels. If the ether through which the ray be
sent were simply warped or in some static stress, the ray, after
reflection, would be brought back to its original plane, which is not
the case. This rotation in the ether is produced by what is going on in
the wire. The ether waves called light are interpreted to imply that
molecules originate them by their vibrations, and that there are as many
ether waves per second as of molecular vibrations per second. In like
manner, the implication is the same, that if there be rotations in the
ether they must be produced by molecular rotation, and there must be as
many rotations per second in the ether as there are molecular rotations
that produce them. The space about a wire carrying a current is often
pictured as filled with whorls indicating this motion (Fig. 14), and one
must picture to himself, not the wire as a whole rotating, but each
individual molecule independently. But one is aware that the molecules
of a conductor are practically in contact with each other, and that if
one for any reason rotates, the next one to it would, from frictional
action, cause the one it touched to rotate in the opposite direction,
whereas, the evidence goes to show that all rotation is in the same
direction.

[Illustration: FIG. 14.]

How can this be explained mechanically? Recall the kind of action that
constitutes heat, that it is not translatory action in any degree, but
vibratory, in the sense of a change of form of an elastic body, and
this, too, of the atoms that make up the molecule of whatever sort. Each
atom is so far independent of every other atom in the molecule that it
can vibrate in this way, else it could not be heated. The greater the
amplitude of vibration, the more free space to move in, and continuous
contact of atoms is incompatible with the mechanics of heat. There must,
therefore, be impact and freedom alternating with each other in all
degrees in a heated body. If, in any way, the atoms themselves _were_
made to rotate, their heat impacts not only would restrain the
rotations, but the energy also of the rotation motion would increase the
vibrations; that is, the heat would be correspondingly increased, which
is what happens always when an electric current is in a conductor. It
appears that the cooler a body is the less electric resistance it has,
and the indications are that at absolute zero there is no resistance;
that is, impacts do not retard rotation, but it is also apparent that
any current sent through a conductor at that temperature would at once
heat it. This is the same as saying that an electric current could not
be sent through a conductor at absolute zero.

So far, mechanical conceptions are in accordance with electrical
phenomena, but there are several others yet to be noted. Electrical
phenomena has been explained as molecular or atomic phenomena, and there
is one more in that category which is well enough known, and which is so
important and suggestive, that the wonder is its significance has not
been seen by those who have sought to interpret electrical phenomena.
The reference is to the fact that electricity cannot be transmitted
through a vacuum. An electric arc begins to spread out as the density of
the air decreases, and presently it is extinguished. An induction spark
that will jump two or three feet in air cannot be made to bridge the
tenth of an inch in an ordinary vacuum. A vacuum is a perfect
non-conductor of electricity. Is there more than one possible
interpretation to this, namely, that electricity is fundamentally a
molecular and atomic phenomenon, and in the absence of molecules cannot
exist? One may say, "Electrical _action_ is not hindered by a vacuum,"
which is true, but has quite another interpretation than the implication
that electricity is an ether phenomenon. The heat of the sun in some way
gets to the earth, but what takes place in the ether is not
heat-transmission. There is no heat in space, and no one is at liberty
to say, or think, that there can be heat in the absence of matter.

When heat has been transformed into ether waves, it is no longer heat,
call it by what name one will. Formerly, such waves were called
heat-waves; no one, properly informed, does so now. In like manner, if
electrical motions or conditions in matter be transformed, no matter
how, it is no longer proper to speak of such transformed motions or
conditions as electricity. Thus, if electrical energy be transformed
into heat, no one thinks of speaking of the latter as electrical. If the
electrical energy be transformed into mechanical of any sort, no one
thinks of calling the latter electrical because of its antecedent. If
electrical motions be transformed into ether actions of any kind, why
should we continue to speak of the transformed motions or energy as
being electrical? Electricity may be the antecedent, in the same sense
as the mechanical motion of a bullet may be the antecedent of the heat
developed when the latter strikes the target; and if it be granted that
a vacuum is a perfect non-conductor of electricity, then it is
manifestly improper to speak of any phenomenon in the ether as an
electrical phenomenon. It is from the failure to make this distinction
that most of the trouble has come in thinking on this subject. Some have
given all their attention to what goes on in matter, and have called
that electricity; others have given their attention to what goes on in
the ether, and have called that electricity, and some have considered
both as being the same thing, and have been confounded.

Let us consider what is the relation between an electrified body and the
ether about it.

When a body is electrified, the latter at the same time creates an ether
stress about it, which is called an electric field. The ether stress may
be considered as a warp in the distribution of the energy about the body
(Fig. 15), by the new positions given to the molecules by the process of
electrification. It has been already said that the evidence from other
sources is that atoms, rather than molecules, in larger masses, are what
affect the ether. One is inclined to inquire for the evidence we have as
to the constitution of matter or of atoms. There is only one hypothesis
to-day that has any degree of probability; that is, the vortex-ring
theory, which describes an atom as being a vortex-ring of ether in the
ether. It possesses a definite amount of energy in virtue of the motion
which constitutes it, and this motion differentiates it from the
surrounding ether, giving it dimensions, elasticity, momentum, and the
possibility of translatory, rotary, vibratory motions, and combinations
of them. Without going further into this, it is sufficient, for a
mechanical conception, that one should have so much in mind, as it will
vastly help in forming a mechanical conception of reactions between
atoms and the ether. An exchange of energy between such an atom and the
ether is not an exchange between different kinds of things, but between
different conditions of the same thing. Next, it should be remembered
that all the elements are magnetic in some degree. This means that they
are themselves magnets, and every magnet has a magnetic field unlimited
in extent, which can almost be regarded as a part of itself. If a magnet
of any size be moved, its field is moved with it, and if in any way the
magnetism be increased or diminished, the field changes correspondingly.

[Illustration: FIG. 15.]

Assume a straight bar electro-magnet in circuit, so that a current can
be made intermittent, say, once a second. When the circuit is closed and
the magnet is made, the field at once is formed and travels outwards at
the rate of 186,000 miles per second. When the current stops, the field
adjacent is destroyed. Another closure develops the field again, which,
like the other, travels outwards; and so there may be formed a series of
waves in the ether, each 186,000 miles long, with an electro-magnetic
antecedent. If the circuit were closed ten times a second, the waves
would be 18,600 miles long; if 186,000 times a second, they would be but
one mile long. If 400 million of millions times a second, they would be
but the forty-thousandth of an inch long, and would then affect the eye,
and we should call them light-waves, but the latter would not differ
from the first wave in any particular except in length. As it is proved
that such electro-magnetic waves have all the characteristics of light,
it follows that they must originate with electro-magnetic action, that
is, in the changing magnetism of a magnetic body. This makes it needful
to assume that the atoms which originate waves are magnets, as they are
experimentally found to be. But how can a magnet, not subject to a
varying current, change its magnetic field? The strength or density of a
magnetic field depends upon the form of the magnet. When the poles are
near together, the field is densest; when the magnet is bent back to a
straight bar, the field is rarest or weakest, and a change in the form
of the magnet from a U-form to a straight bar would result in a change
of the magnetic field within its greatest limits. A few turns of
wire--as has been already said--wound about the poles of an ordinary
U-magnet, and connected to an ordinary magnetic telephone, will enable
one, listening to the latter, to hear the pitch of the former loudly
reproduced when the magnet is struck like a tuning-fork, so as to
vibrate. This shows that the field of the magnet changes at the same
rate as the vibrations.

Assume that the magnet becomes smaller and smaller until it is of the
dimensions of an atom, say for an approximation, the fifty-millionth of
an inch. It would still have its field; it would still be elastic and
capable of vibration, but at an enormously rapid rate; but its vibration
would change its field in the same way, and so there would be formed
those waves in the ether, which, because they are so short that they can
affect the eye, we call light. The mechanical conceptions are
legitimate, because based upon experiments having ranges through nearly
the whole gamut as waves in ether.

The idea implies that every atom has what may be loosely called an
electro-magnetic grip upon the whole of the ether, and any change in the
former brings some change in the latter.

Lastly, the phenomenon called induction may be mechanically conceived.

It is well known that a current in a conductor makes a magnet of the
wire, and gives it an electro-magnetic field, so that other magnets in
its neighbourhood are twisted in a way tending to set them at right
angles to the wire. Also, if another wire be adjacent to the first, an
electric current having an opposite direction is induced in it. Thus:

Consider a permanent magnet A (Fig. 15), free to turn on an axis in the
direction of the arrow. If there be other free magnets, B and C, in
line, they will assume such positions that their similar poles all point
one way. Let A be twisted to a position at right angles, then B will
turn, but in the opposite direction, and C in similar. That is, if A
turn in the direction of the hands of a clock, B and C will turn in
opposite directions. These are simply the observed movements of large
magnets. Imagine that these magnets be reduced to atomic dimensions, yet
retaining their magnetic qualities, poles and fields. Would they not
evidently move in the same way and for the same reason? If it be true,
that a magnet field always so acts upon another as to tend by rotation
to set the latter into a certain position, with reference to the stress
in that field, then, _wherever there is a changing magnetic field, there
the atoms are being adjusted by it_.

[Illustration: FIG. 16.]

Suppose we have a line of magnetic needles free to turn, hundreds or
thousands of them, but disarranged. Let a strong magnetic field be
produced at one end of the line. The field would be strongest and best
conducted along the magnet line, but every magnet in the line would be
compelled to rotate, and if the first were kept rotating, the rotation
would be kept up along the whole line. This would be a mechanical
illustration of how an electric current travels in a conductor. The
rotations are of the atomic sort, and are at right angles to the
direction of the conductor.

That which makes the magnets move is inductive magnetic ether stress,
but the advancing motion represents mechanical energy of rotation, and
it is this motion, with the resulting friction, which causes the heat in
a conductor.

What is important to note is, that the action in the ether is not
electric action, but more properly the result of electro-magnetic
action. Whatever name be given to it, and however it comes about, there
is no good reason for calling any kind of ether action electrical.

Electric action, like magnetic action, begins and ends in matter. It is
subject to transformations into thermal and mechanical actions, also
into ether stress--right-handed or left-handed--which, in turn, can
similarly affect other matter, but with opposite polarities.

In his _Modern Views of Electricity_, Prof. O. J. Lodge warns us, quite
rightly, that perhaps, after all, there is no such _thing_ as
electricity--that electrification and electric energy may be terms to be
kept for convenience; but if electricity as a term be held to imply a
force, a fluid, an imponderable, or a thing which could be described by
some one who knew enough, then it has no degree of probability, for
spinning atomic magnets seem capable of developing all the electrical
phenomena we meet. It must be thought of as a _condition_ and not as an
entity.


THE END


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Transcriber's Note

Minor typographical corrections have been made without comment.
Inconsistencies in hyphenation, and the author's use of commas
when writing large numbers, have been retained.