his scheme can neither generate matter
nor force, as we have already seen, it needs no further discussion in
this connection.

The fact is simply this, a chemical perpetual motion is as impossible as
a mechanical one. The discovery of the convertibility of forces shows
this. The development theory of the generation of motion by processes of
the self-heating or the self-cooling of the machine, or by chemical
actions and reactions, is, in its last analysis, only a big perpetual
motion humbug.

Even were the rotation, and the cooling process, to take place, as is
supposed, _no such results would proceed from these combined operations
as the case requires_; for, according to the theory, as the cooling and
contracting rings revolve in the verge of a vortex of fluid less dense
than themselves, one of these two results must take place: either, as is
most probable, from their exceeding tenuity, the rings will break at
once into fragments, when, instead of flying outward, they will sink
toward the center, and, as long as they are heavier than the surrounding
fluid, _they will stay there_; and, as the cooling goes on on the
outside, so will the concentration of the heavier matter, till we have
_one_ great spheroid, with a solid center, liquid covering, and gaseous
atmosphere. A vortex will never make, nor allow to exist beyond its
center, planets heavier than the fluid of which it is composed. The
other alternative, and the one which La Place selected, was the
supposition that the cooling and contracting rings did not at first
break up into pieces, but retained their continuity; but, contrary to
all experience and reason, he supposed that these cooling rings kept
contracting and widening out from the heated mass, at the same time. The
only fluid planetary rings which we can examine--those of Saturn--have
been closing in on the planet since the days of Huygens, and eventually
will be united with the body of the planet. Every boy who has seen a
blacksmith hoop a cart-wheel has learned the principle, that a heated
ring contracts as it cools, and in doing so presses in upon the mass
around which it clings. But, according to this nebular notion, the
fire-mist keeps cooling and shrinking up, while the rings, of the very
same heat and material, keep cooling faster, and widening out from it; a
piece of schismatical behavior without a parallel among solids or
fluids, either in heaven or earth, or under the earth.

Plateau's illustratio