vacuum, as well as in the densest substances.
But the mind cannot admit the existence
of an imponderable fluid; for, if it is a
fluid, it is a body. Now, all bodies are
ponderable; therefore, the ether is ponderable.
We certainly know that the ether has not
been weighed, but we have no right to assert
that it has no weight. The ether is the
essential principle of all bodies; it is their
primordial state; it is matter in a condition
of extreme tenuity, which prevents its being
palpable, seizable, or weighable. Hydrogen
is the first material body, in respect to
density, of which we are able to take
cognisance; hydrogen is ether condensed, tangible,
and ponderable. Dr. Prout propounded the
hypothesis that matter is uniform in its
nature, and that all atomic weights are
multiples of the weight of hydrogen. It would
now appear that the weight of hydrogen is a
multiple of that of the ether, or of unknown
intermediate bodies, which are themselves
multiples of ether. Several gases have been
reduced to a liquid, and even a solid form, by
the application of great compression and
extreme cold; azote and hydrogen have
hitherto resisted the efforts even of a Faraday
to make them liquid. The last gaseous
substance which will be liquefied by human
agency is, doubtless, the ether.

Whence comes the matter of which the
heavenly bodies are composed? It is
generally called cosmic matter; that is, universal
matter; but does this universal matter differ
from what may be called universal ether?
Many natural  philosophers believe that
atmospheric matter is produced by the
condensation of etherial matter. But if the ether is
capable of condensation so as to form the
atmosphere, the atmosphere in turn may be
capable of condensation so as to form solid
globes, such as the planets with the animals
and plants which live on them. But the
existence or non-existence of the ether derives
its great importance from its intimate
connection witli the speculations that have been
put forth respecting the nature of light. It
is the all-pervading presence of a medium,
which forms, throughout space, a material
communication to the very distantest visible
bodies, which serves as the fundamental
hypothesis of the theory of undulations.
Whether this medium be (as seems probable)
or be not, a continuation of our own proper
atmosphere, the fact that there is such a
medium derives great support from the
powerful arguments which are now brought
forward in maintenance of the undulatory
theory. It would be desirable to solve the
problem, What is the absolute density of the
luminous ether at any given point of space?
But the data hitherto attainable are insufficient
for its solution. It may be remarked,
however, that, according to the law laid down
by Boyle, the luminous medium is incomparably
denser than our atmosphere would be
were it extended to the interplanetary spaces.
The ether may also be perhaps regarded as
the propagating agent of electricity and
magnetism as well as of light. At the beginning
of the present century, the discoveries of
Young, of Fresnel, of Malus, and Arago,
proclaimed to the world several optical
phenomena which were inexplicable on the
supposition that light was the effect of luminous
corpuscules shot out from the sun wiih
immense velocity, while they were easily
explained by the admission that celestial space
is filled with an excessively-rarified elastic
gas.

In this latter case, the sun, not having to
dart in all directions molecules of light and
heat which are to travel with inconceivable
swiftness, may cease to be regarded as a
monstrous planet everlastingly devoured by
fire. The part which the sun has to play, on
the modern hypothesis, is simply to impress
on the matter which fills all space, a powerful
vibratory movement which extends, in the
form of luminous waves, as far as the most
distant planets and farther, thereby supplying
them with light and heat. These luminous
waves, or undæ, are the reason why the
system is called the undulatory theory.

The views respecting the nature of the
ether, of which we now conclude our sketch,
are what are entertained, to a greater or less
extent, by almost all the scientific pioneers of
the day; notwithstanding which, it is not yet
completely proved that the ether itself has
any real or actual existence in nature. The
grand quarrel of Plenum versus Vacuum,
which mounts to a respectable antiquity and
had already attained importance in the time
of Pythagoras, can scarcely be said to be even
yet a settled question. There is little more
than circumstantial evidence in proof of the
allegation. It is consequently still so
interesting a subject of debate, that the five
classes of the Institute of Paris, at their
annual meeting in August, eighteen hundred
and fifty-six, decreed their grand triennial prize
to M. Fizeau, whose works have for their
object the demonstration of the falsity of the
hypothesis of a vacuum, the establishment of
the presence of the ether throughout heavenly
space, the proof of the undulatory theory,
and the measurement of the velocity of
propagation in light.

WHITE WASHERTON.

No man loves the metropolis more than I
do. I cannot go so far in my admiration of
Fleet Street as certain eminent literary
authorities, nor can I altogether admit that
beyond Hyde Park it is a desert; but I will
support any man who boldly asserts that
you can get everything in London that
you can get in the country; and get it
a hundred-fold better. Yet, I must reserve
one peculiar and important exception;
and that is, the metropolitan organization
for the relief of insolvent debtors.