may be said that the entropy of the world is continually increasing.
Thus the quantity of energy existing in the Universe remains constant,
but transforms itself little by little into heat uniformly distributed
at a temperature everywhere identical. In the end, therefore, there
will be neither chemical phenomena nor manifestation of life; the
world will still exist, but without motion, and, so to speak, dead.

These consequences must be admitted to be very doubtful; we cannot in
any certain way apply to the Universe, which is not a finite system, a
proposition demonstrated, and that not unreservedly, in the sharply
limited case of a finite system. Herbert Spencer, moreover, in his
book on _First Principles_, brings out with much force the idea that,
even if the Universe came to an end, nothing would allow us to
conclude that, once at rest, it would remain so indefinitely. We may
recognise that the state in which we are began at the end of a former
evolutionary period, and that the end of the existing era will mark
the beginning of a new one.

Like an elastic and mobile object which, thrown into the air, attains
by degrees the summit of its course, then possesses a zero velocity
and is for a moment in equilibrium, and then falls on touching the
ground to rebound, so the world should be subjected to huge
oscillations which first bring it to a maximum of entropy till the
moment when there should be produced a slow evolution in the contrary
direction bringing it back to the state from which it started. Thus,
in the infinity of time, the life of the Universe proceeds without
real stop.

This conception is, moreover, in accordance with the view certain
physicists take of the principle of Carnot. We shall see, for example,