thstand the force of such figures. Mathematics has ever been the
implacable foe of scientific romances. The constant object of Laplace
was the explanation of the great phenomena of nature according to
inflexible principles of mathematical analysis. No philosopher, no
mathematician, could have guarded himself more cautiously against a
propensity to hasty speculation. No person dreaded more the scientific
errors which cajole the imagination when it passes the boundary of fact,
calculation, and analogy.

Once, and once only, did Laplace launch forward, like Kepler, like
Descartes, like Leibnitz, like Buffon, into the region of conjectures.
But then his conception was nothing less than a complete cosmogony. All
the planets revolve around the sun, from west to east, and in planes
only slightly inclined to each other. The satellites revolve around
their respective primaries in the same direction. Both planets and
satellites, having a rotary motion, turn also upon their axes from west
to east. Finally, the rotation of the sun also is directed from west to
east. Here, then, is an assemblage of forty-three movements, all
operating alike. By the calculus of probabilities, the odds are four
thousand millions to one that this coincidence in direction is not the
effect of accident.

It was Buffon, I think, who first attempted to explain this singular
feature of our solar system. "Wishing, in the explanation of phenomena,
to avoid recourse to causes which are not to be found in nature," the
celebrated academician sought for a physical cause for what is common to
the movements of so many bodies differing as they do in magnitude, in
form, and in their distances from the centre of attraction. He imagined
that he had discovered such a physical cause by making this triple
supposition: a comet fell obliquely upon the sun; it pushed before it a
torrent of fluid matter; this substance, transported to a greater or
less distance from the sun according to its density, formed by
condensation all the known planets. The bold hypothesis is subject to
insurmountable difficulties. I proceed to indicate, in a few words, the
cosmogonic system which Laplace substituted for it.

According to Laplace, the sun was, at a remote epoch, the central
nucleus of an immense nebula, which possessed a very high temperature,
and extended far beyond the region in which Uranus now revolves. No
planet was then in existence. The solar nebula was endowed with a
genera