One great principle to be kept in view in this investigation, is that
which teaches that the product of matter, angular velocity, and distance
from the centre of motion, must ever be a constant quality in every
balanced system. Yet this principle does not seem to be observed in the
case of the planets. We will, however, endeavor to show that it is
rigidly observed. And we will extend the principle further, and contend
that all the phenomena of nature are consequences of the constant
tendency of matter to conform to this principle of equilibrium, when
suffering temporary derangement from the operation of other laws. That
throughout the system of nature, equal spaces possess equal force. That
what we call temperature, is nothing more than the motion of equilibrium
or atomic momentum of space; or, in other words, that if all space were
fluid, and in a state of equilibrium, the product of each atom of equal
volume, by its motion would be a constant quality. From this it would
seem to follow, that the specific heat of bodies should be inversely as
their atomic weights; and this does, no doubt, _approximately_ obtain as
was proved by Dulong and Petit, for metallic substances, more recently
by Regnault, and has since been extended by Garnier to other substances.
But it is to the gaseous state that we must look for confirmation of the
principle that equal spaces possess equal power; and in doing so, it
will be necessary to bear in mind, that the ether also is affected by
temperature.