"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
until by this motion they came upon the equator.