But alas for our mechanical model consisting of the cloud of little elastic
solids flying about among one another. Though each particle have absolutely
perfect elasticity, the end must be pretty much the same as if it were but
imperfectly elastic. The average effect of repeated and repeated mutual
collisions must be to gradually convert all the translational energy into
energy of shriller and shriller vibrations of the molecule. It seems
certain that each collision must have something more of energy in
vibrations of very finely divided nodal parts than there was of energy in
such vibrations before the impact. The more minute this nodal subdivision,
the less must be the tendency to give up part of the vibrational energy
into the shape of translational energy in the course of a collision; and I
think it is rigorously demonstrable that the whole translational energy
must ultimately become transformed into vibrational energy of higher and
higher nodal subdivisions if each molecule is a continuous elastic solid.
Let us, then, leave the kinetic theory of gases for a time with this
difficulty unsolved, in the hope that we or others after us may return to
it, armed with more knowledge of the properties of matter, and with sharper
mathematical weapons to cut through the barrier which at present hides from
us any view of the molecule itself, and of the effects other than mere
change of translational motion which it experiences in collision.

To explain the elasticity of a gas was the primary object of the kinetic
theory of gases. This object is only attainable by the assumption of an
elasticity more complex in character, and more difficult of explanation,
than the elasticity of gases--the elasticity of a solid. Thus, even if the
fatal fault in the theory, to which I have alluded, did not exist, and if
we could be perfectly satisfied with the kinetic theory of gases founded on
the collisions of elastic solid molecules, there would still be beyond it a
grander theory which need not be considered a chimerical object of
scientific ambition--to explain the elasticity of solids. But we may be