SPECIFIC HEAT.

It has been contended by some that the medium which conveys the
impression of light through transparent, bodies, is necessarily more
dense within the body than without; but according to this theory the
converse is true. A ray of light is a mechanical impulse, propagated
through an elastic medium, and, like a wave in water, tends to the side
of least resistance. Within a refracting body the ether is rarefied, not
only by the proximity of the atoms of the body (or its density), but
also by the motions of those atoms; so that if two _simple_ gases of
different specific gravity be made equal in density by compression,
their refraction will be approximately as their specific heats. In the
case of solids and liquids, or even compound gases, there is a continual
absorption of motion to produce the cohesion of composition and
aggregation. And the specific heats of compound gases will be found
greater than those of simple gases, in proportion to the loss of volume
by combination, _ceteris paribus_. If impenetrability be a law of
matter, the more a portion of atomic matter is condensed, the less ether
will be found in the same space. The same is also true when the natural
density or specific gravity of a gas is greater than that of another.
And the lighter the gas, the more will this circumstance vitiate the
experiments to determine its specific heat. There is, therefore, this
great source of fallacy in such experiments, viz.: that the ether
permeates all fluids and solids, and that _its specific heat probably
far exceeds that of all other matter_. This is a fundamental position of
the theory, in support of which we will introduce a fact announced by
M. V. Regnault, which was published in the Comptes Rendus of the French
Academy for April, 1853. He says: "In the course of my researches I have