to the small
space which encloses them by the fortuity of chance alone, and he has
concluded that this group of stars, and similar groups which the skies
present to us, are the necessary result of the condensation of a nebula,
with several nuclei, and it is evident that a nebula, by continually
contracting, towards these various nuclei, at length would form a group
of stars similar to the Pleiades. The condensation of a nebula with two
nuclei would form a system of stars close together, turning one upon
the other, such as those double stars of which we already know the
respective movements.

"But how did the solar atmosphere determine the movements of the
rotation and revolution of the planets and satellites? If these bodies
had penetrated very deeply into this atmosphere, its resistance would
have caused them to fall into the sun. We can therefore conjecture that
the planets were formed at their successive limits by the condensation
of a zone of vapors which the sun, on cooling, left behind, in the plane
of his equator.

"Let us recall the results which we have given in a preceding chapter.
The atmosphere of the sun could not have extended indefinitely. Its
limit was the point where the centrifugal force due to its movement
of rotation balanced its weight. But in proportion as the cooling
contracted the atmosphere, and those molecules which were near to them
condensed upon the surface of the body, the movement of the rotation
increased; for, on account of the Law of Areas, the sum of the areas
described by the vector of each molecule of the sun and its atmosphere
and projected in the plane of the equator being always the same, the
rotation should increase when these molecules approach the centre of the
sun. The centrifugal force due to this movement becoming thus larger,
the point where the weight is equal to it is nearer the sun. Supposing,
then, as it is natural to admit, that the atmosphere extended at some
period to its very limits, it should, on cooling, leave molecules behind
at this limit and at limits successively occasioned by the increased
rotation of the sun. The abandoned molecules would continue to revolve
around this body, since their centrifugal force was balanced by their
weight. But this equilibrium not arising in regard to the atmospheric
molecules parallel to the solar equator, the latter, on account of their
weight, approached the atmosphere as they condensed, and did not cease
to belong to it unt