The second popular meeting of the season was held in Queen-street Hall
on the evening of Wednesday, the 24th ult. Every available place in the
hall was filled.
The exhibition consisted of a very fine series of views in Ireland,
kindly lent by Messrs. Pumphrey Brothers, of Birmingham, and of a number
of copies of Erskine Nicol’s pictures of Irish character, prepared from
negatives kindly lent for the purpose by Mr. Tunny. The pictures were
arranged in the form of a tour, beginning in the north at the Giant’s
Causeway, working south to Dublin, and including the Lakes of Killarney
and some of the finest scenery in the country.
The descriptive lecture was undertaken by Mr. J. Richard Marquis,
R.H.A.; but being evidently new to the business, and unaccustomed to
speak in the dark, the lecturer failed to come up to the expectations of
the audience. We hope, however, to hear Mr. Marquis again, as he has in
him the elements from which good lecturers are formed; and from his
ability as an artist, and his thorough acquaintance with what
constitutes a good picture, we are certain that with a little practice
he will make a capital guide in such exhibitions.
The exhibition was thoroughly successful, and at its close hearty votes
of thanks were awarded to Messrs. Pumphrey Brothers, Mr. Tunny, and the
lecturer.
We may mention in connection with this that last evening (Thursday) the
same pictures were exhibited as one of the series of popular lectures
given under the auspices of the Northern District Lecture Association.
On this occasion the lecture was delivered by Dr. John Nicol, who stated
at the beginning that he was in a position to do what rarely could
practically be done by a lecturer—that is, praise his own lecture. He
(Dr. Nicol), however, went on to say:—“The lecture is not mine, but has
been kindly sent along with the pictures by Messrs. Pumphrey; and it is
so much better than anything that I could produce, I shall give it just
as it is, except, perhaps, the introduction here and there of a story or
anecdote, by way of a ‘mouth-opener,’ as our transatlantic friends would
say.” Both lecture and exhibition were very successful, and elicited
almost continuous applause.
At the close Dr. Nicol exhibited the recently-patented “wheel of life,”
as manufactured by Messrs. Pumphrey, and described in THE BRITISH
JOURNAL OF PHOTOGRAPHY a few weeks since. He explained the principle of
its construction, and gave much credit to the inventor, who, he said,
had succeeded in doing admirably what he (Dr. Nicol) and many others had
vainly tried to do for years.
At the termination of the exhibition, votes of thanks were awarded to
Dr. Nicol, to Messrs. Pumphrey for the pictures, and to Messrs. Yerbury
and Lothian for the admirable way in which they had managed the lantern.
------------------------------------------------------------------------
Correspondence.
THE CONSTITUTION OF MATTER AND ITS MOTIONS.—UNIVERSAL GRAVITATION
PRODUCED BY THE MOTIONS OF ETHER.—HYPOTHESIS OF M. L’ABBÉ LERAY.—M.
RICHE ON THE NEW CHEMICAL NOTATION.—NEW SENSITIVE PIGMENT PAPER.
In one of my recent letters to this Journal I was deploring the want of
some grand hypothesis which would embrace in one general law all the
mechanical phenomena of nature—universal gravitation, cohesion, chemical
affinity, electricity, magnetism, light, heat, &c.—and lo! just such a
hypothesis has turned up and been explained to me by its author—a man
whom I am compelled to regard, without any exaggeration, as one of the
great geniuses of the present day. I allude to M. L’Abbé Leray, author
of a work to which I referred in a recent letter, entitled _Constitution
de la Matière et ses Mouvements_.
I will endeavour to give an outline—but it can only be an outline—of
this startling hypothesis, which makes universal gravitation an effect
of the motions of ether, and dispels the idea hitherto entertained that
it is an attractive force inherent in particles of matter, by which they
are enabled to exert a pull upon other particles at a distance from them
in space.
Sir Isaac Newton, the immortal discoverer of the law of universal
gravitation (which asserts that every particle of matter in the universe
attracts every other particle with a force which varies directly as the
mass and inversely as the square of the distance), himself believed that
this law would be found, at some future time, to result from the motions
of a subtle fluid which occupied space, the atoms of which, by impinging
against ponderable matter, produce the observed effect of weight or
gravitation. He could not conceive of ponderable matter possessing any
_inherent_ property by which it was enabled to act upon other ponderable
matter _at a distance_. He could not really believe in an inherent
central force of attraction residing in a material atom, by which it
could draw towards itself another such atom situated at a distance, or
that it could affect other matter in any way than by the impact of
intervening atoms; and he predicted that some day the _cause_ of
universal gravitation would be discovered. That day seems now to have
arrived, and the discovery to have been actually made.
I had read M. Leray’s extraordinary work with a great deal of interest,
but there were still some unexplained points in his hypothesis which
remained to be cleared up and some difficulties to be discussed. As he
resides at an ecclesiastical institution within an easy walk of Redon, I
visited him a few days ago, by appointment, for the express purpose of
having a long talk over his hypothesis; and a very pleasant afternoon I
had with him, leaving more deeply impressed than ever with a sense of
his great abilities and originality. In fact, I seem to have made the
acquaintance of a second Sir Isaac or Laplace.
The following is an outline of his theory; but of course no
demonstration of any part of it can be made within the limits of this
letter:—
Space is filled with a subtle ether, consisting of atoms in motion.
These atoms are elastic—a property which they possess in virtue of being
able to change their form, though not their volume, during impact and to
recover it again. Their form is spherical, they are all equal, and their
diameter is very small compared with that of the atoms of ponderable
matter, and also with their general distance apart. This ether is,
therefore, an exceedingly rare medium. When the atoms impinge against
each other they rebound like billiard balls, and in all their motions
they obey the common mechanical laws of inertia and impact, and no other
laws whatever. They cannot act upon each other at a distance, and
therefore no attractive or repulsive force exists between them.
If only one of these atoms were to exist in space it would move in a
straight line with uniform velocity until it reached the limit of space;
that is to say, the boundary by which creation is limited—the boundary
which separates entity from nonentity. Here, being elastic, it would be
reflected, and would then follow another rectilinear course until it
again encountered in another point the boundary of space, where it would
be again reflected; and so on for ever!
If we imagine space filled with an enormous number of such atoms it will
follow that _at every point in space there will be small parallel
currents of them moving in all directions_. Their distance apart being
great in proportion to their size, two contrary currents will not
annihilate each other, but by far the greater number of atoms in one
current will pass those in the other current without impact. Those atoms
which do impinge against opposite atoms, at various angles of incidence,
will rebound and join other currents which are moving in their new
direction.
The state of things above described constitutes what is called “mobile
equilibrium;” for what one current loses by meeting another in an
opposite direction will be imparted to surrounding currents, and these,
in their turn, will give back equal to what they have acquired, so that
compensation will be made, and thus the laws of conservation of force,
and of _vis viva_, will be satisfied.
The velocity with which the atoms move is enormous, and millions of
times greater than the velocity of light.
The reader will observe that there is a vast difference between the
mobile equilibrium of this ether and the equilibrium of air or gas
confined in a closed vessel. The reason why particles of a gas appear to
repel each other is because the ethereal undulations of heat are
vibrating between them. By reducing the temperature and increasing the
pressure gases may be liquified or solidified, in which states no
repulsion exists between their particles.
All ponderable matter is porous; its ultimate atoms are spheres much
larger than the atoms of ether, and much farther apart; the currents of
ether can, therefore, pass through a ponderable body in all directions.
When a current of ether passes through a ponderable body some of the
atoms of ether strike the atoms of the body and rebound; the current,
after passing through the body, will, therefore, be weakened, according
to the number of its atoms which have rebounded in altered
directions—that is to say, according to the number of atoms of the body
which have been struck by atoms of ether. The greater the mass of a body
the greater will be the weakening of the currents of ether which have
passed through it. A current of ether weakened by passing through a body
will gradually regain its original strength by passing through space,
since it will be continually reinforced by other atoms moving in the
same direction as itself.
A single ponderable atom in the midst of currents of ether will be in
equilibrium under their action, because it will be struck equally in all
directions.
But the atoms of a ponderable body will be put into vibratory motion by
the passage through it of currents of ether; these internal motions may
enable us to account for light, heat, magnetism, &c.
When two ponderable bodies exist in space, and currents of ether pass
through them, the two bodies will be impelled towards each other,
because the currents of ether that are between them and tend to keep
them apart are weakened by having passed through the bodies, and are,
therefore, weaker than the currents which impel them towards each other.
This explains what has been called the “attractive force of gravity.”
It will be observed that since currents of ether pass through the bodies
in all directions, the weakened currents between the bodies will be
included within a sort of conical space. The law of attraction according
to the inverse square of the distance is thus accounted for.
Since the weight of a body is the same, no matter how it is turned
about, it follows that the ultimate atoms of all ponderable matter must
be spherical. It follows also from the hypothesis that all the spherical
atoms of ponderable matter are equal, and that there is, chemically
speaking, but one simple substance—the apparent variety depending upon
the mode of aggregation of the atoms into molecules.
Crystals are formed by arranging these spheres in the same way as you
may arrange marbles or pile up cannon balls.
There is nothing in the hypothesis to interfere with the undulating
theory of light, or with any theory that reposes strictly upon observed
facts; but this we may discuss on a future occasion.
I need hardly say that it is in consequence of their great velocity that
the atoms of ether acquire sufficient momentum to communicate sensible
motion to ponderable matter.
Ponderable matter may possibly be composed of the aggregation of
ethereal atoms; but M. Leray thinks not. He can see no good reason why
it should be so.
Cohesion and chemical affinity may be explained on this hypothesis. Its
leading feature is that it explains how such natural phenomena as do not
involve vital or mental action may be explained on the simplest
mechanical principles, and without involving that “bugaboo,” _action at
a distance_. Of course, Dr. Frankland’s ideas of “bonds,” “active and
latent atomicities,” &c., are inadmissible on this hypothesis.
The demonstrations are rigorously given, and the work involves a good
deal of high mathematics. It is utterly impossible to do justice to the
theory in the above brief sketch of it. The theorems of Euclid, if thus
stated, would many of them appear improbable and absurd. The work itself
can be procured from M. Gauthier Villars, 55, Quai des Grands Augustins,
Paris, price three francs. It is copiously illustrated with woodcuts. A
new edition has just appeared.
Some idea of the distance between the atoms of ponderable matter, when
in the form of gas, may be gathered from a remark of Dr. Mann’s in his
_Guide to a Knowledge of Life_, at page 13, where he says:—
“It can be shown to be highly probable that the ultimate atoms
of gases are at least one hundred times their own diameter
asunder even when those gases are held in confined vessels.”
The earth and the moon are, therefore, about three times as near
together, in proportion to the diameter of the earth, as two atoms of a
gas are, if the above remark be true.
In Sir Isaac Newton’s corpuscular theory of light the atoms emitted from
the sun were supposed to follow one another at a distance of about a
thousand miles apart! Under such circumstances the impact of two atoms
of intersecting rays of light would be a comparatively rare event.
M. Leray asserts that the law of gravitation is only an approximation to
the truth, and that it is modified by the volumes of bodies. The proof
of this he expects will be found some day in the motions of comets,
which rapidly change their volume.
Elective affinity he supposes to depend upon the different forms of
crystals, two crystals which present plane faces towards each other
being more easily pushed together by the atoms of ether than two
crystals in which a solid angle or an edge of one is presented to a
plane face of the other.
The sun, planets, fixed stars, nebulæ, &c., are, of course, perpetually
riddled through and through, in all directions, by currents of ether.
That is why the heavenly bodies gravitate towards each other, as
explained in a preceding paragraph.
With respect to reflection at the boundary of space, it is an idea which
grows upon you the more you think of it. Enormous as creation is it is
impossible to conceive of its having _no_ limit. What, then, is beyond
that limit?—Nothing. Not even space in which matter can exist; no
_place_ even for matter. On reaching the boundary which separates an
entity (for space is an entity) from a nonentity matter must be
reflected, if elastic; or it must roll for ever against the boundary of
space, if inelastic. This conclusion seems to me inevitable; there is no
escape from it.
In the new edition of M. Leray’s book he modifies the theory which I
have endeavoured briefly to explain in the foregoing paragraphs by
supposing that, instead of one ether, there are two in a state of
mixture, the second being a grosser fluid, and its atoms larger than
those of the other. It is these larger atoms of the grosser fluid which,
by their transversal vibrations, produce the phenomena of light, heat,
&c. These larger atoms do not suffer the same swift motion of
translation through space as the smaller atoms of the subtler fluid.
They have no greater motion of translation than ponderable atoms have.
It may be asked—What is the difference between ponderable and
imponderable matter, and why are the atoms of ether imponderable? To
this query a satisfactory answer is given; but I must refer the reader
to the book for it. Were I to enter upon any demonstrations an entire
number of this Journal would not contain half that could be said.
I have proved in an independent manner, and different from that of Père
Leray, that two equal, penetrable spheres of ponderable matter, existing
in space at a distance apart which is large in proportion to their
diameters, will be impelled towards each other by the impact of ethereal
matters, according to a law which is approximately that of the inverse
square of the distance. When the spheres are brought to within a much
shorter distance of each other the law ceases to be approximately true.
The law of gravitation may, therefore, be only approximately true for
particles of matter at a great distance apart in proportion to their
diameters. The only observations which appear to confirm the law are
those which have been made upon the heavenly bodies; and here we have a
case of a distance apart many times the diameters of the bodies, even
between satellites and their primaries.
But before any one can seriously accept this new hypothesis a vast deal
more thought and study must be bestowed upon it than I have yet had time
to give it.
I will send the demonstration referred to for insertion in a future
number of this Journal if our Editors think fit. The subject is not
foreign to photography, but intimately connected with it as a science.
According to the new hypothesis, new definitions must be given of MASS
and DENSITY. According to M. Leray, “the mass of an atom is equal to its
volume, and the mass of a body is equal to the sum of the volumes of its
atoms.”
“If we call M the mass of a body, and V its apparent volume, the
fraction M/V is the absolute density of the body. The absolute
density is, therefore, unity for an atom, and varies from 0 to 1
for all bodies.”
If two bodies have the same apparent volume, their densities are
proportional to their masses.
I have been looking through a capital French work on Chemistry,
published in 1870, by M. Alfred Riche, lecturer at the Polytechnic
School at Paris. He uses the old notation and table of equivalents; but
strongly advises a change to the new, which he explains very nicely, and
pretty much as our lecturer has done. Whenever the atomic weight of an
element is given according to the new table its symbol has a bar drawn
across it. Something of this sort should always be observed, in order to
avoid confusion between the old and new formulæ.
* * * * *
I have just received a letter from Mr. J. R. Johnson, containing a most
beautiful carbon print. He asks me what I think of it. My reply is
simply this—that it is the most wonderfully fine print I have ever seen
upon paper.