isappear. The
fluid would frequently overflow its boundaries, to ravage continents
even to the height of the snowy peaks which lose themselves in
the clouds.

No one was more sagacious than Laplace in discovering intimate relations
between phenomena apparently unrelated, or more skillful in deducing
important conclusions from such unexpected affinities. For example,
toward the close of his days, with the aid of certain lunar
observations, with a stroke of his pen he overthrew the cosmogonic
theories of Buffon and Bailly, which were so long in favor. According to
these theories, the earth was hastening to a state of congelation which
was close at hand. Laplace, never contented with vague statements,
sought to determine in numbers the rate of the rapid cooling of our
globe which Buffon had so eloquently but so gratuitously announced.
Nothing could be more simple, better connected, or more conclusive than
the chain of deductions of the celebrated geometer. A body diminishes in
volume when it cools. According to the most elementary principles of
mechanics, a rotating body which contracts in dimensions must inevitably
turn upon its axis with greater and greater rapidity. The length of the
day has been determined in all ages by the time of the earth's rotation;
if the earth is cooling, the length of the day must be continually
shortening. Now, there exists a means of ascertaining whether the length
of the day has undergone any variation; this consists in examining, for
each century, the arc of the celestial sphere described by the moon
during the interval of time which the astronomers of the existing epoch
call a day; in other words, the time required by the earth to effect a
complete rotation on its axis, the velocity of the moon being in fact
independent of the time of the earth's rotation. Let us now, following
Laplace, take from the standard tables the smallest values, if you
choose, of the expansions or contractions which solid bodies experience
from changes of temperature; let us search the annals of Grecian,
Arabian, and modern astronomy for the purpose of finding in them the
angular velocity of the moon: and the great geometer will prove, by
incontrovertible evidence founded upon these data, that during a period
of two thousand years the mean temperature of the earth has not varied
to the extent of the hundredth part of a degree of the centigrade
thermometer. Eloquence cannot resist such a process of reasoning, or
wi