Kant had done. He started with a sun ready made,[1151] and surrounded
with a vast glowing atmosphere, extending into space out beyond the
orbit of the farthest planet, and endowed with a slow rotatory motion.
As this atmosphere or nebula cooled, it contracted; and as it
contracted, its rotation, by a well-known mechanical law, became
accelerated. At last a point arrived when tangential velocity at the
equator increased beyond the power of gravity to control, and
equilibrium was restored by the separation of a nebulous ring revolving
in the same period as the generating mass. After a time, the ring broke
up into fragments, all eventually reunited in a single revolving and
rotating body. This was the first and farthest planet.

Meanwhile the parent nebula continued to shrink and whirl quicker and
quicker, passing, as it did so, through successive crises of
instability, each resulting in, and terminated by, the formation of a
planet, at a smaller distance from the centre, and with a shorter period
of revolution than its predecessor. In these secondary bodies the same
process was repeated on a reduced scale, the birth of satellites ensuing
upon their contraction, or not, according to circumstances. Saturn's
ring, it was added, afforded a striking confirmation of the theory of
annular separation,[1152] and appeared to have survived in its original
form in order to throw light on the genesis of the whole solar system;
while the four first discovered asteroids offered an example in which
the _debris_ of a shattered ring had failed to coalesce into a single
globe.

This scene of cosmical evolution was a characteristic bequest from the
eighteenth century to the nineteenth. It possessed the self-sufficing
symmetry and entireness appropriate to the ideas of a time of
renovation, when the complexity of nature was little accounted of in
comparison with the imperious orderliness of the thoughts of man. Since
its promulgation, however, knowledge has transgressed many boundaries,
and set at naught much ingenious theorising. How has it fared with
Laplace's sketch of the origin of the world? It has at least not been
discarded as effete. The groundwork of speculation on the subject is
still furnished by it. It is, nevertheless, admittedly inadequate. Of
much that exists it gives no account, or an erroneous one. The march of
events certainly did not everywhere--even if it did anywhere--follow the
exact path prescribed for it. Yet modern