as been aptly called, "a
universal Fire-Mist."[28]

When the theory is limited to the explanation of the origin of the
planets and their satellites, the original condition of our solar system
is assumed to have been widely different from what it now is; the sun is
supposed to have existed for a time alone, to have revolved upon his
axis, and to have been surrounded with an atmosphere expanded by intense
heat, and extending far beyond the limits of our system as it now
exists. This solar atmosphere revolved, like the sun itself, around its
axis; but its heat, constantly radiated into sidereal space, gradually
diminished, and the atmosphere being contracted in proportion as it
cooled, the rapidity of its rotation was accelerated, until it reached
the point at which the central attraction was overcome by the
centrifugal force, and then a zone of vapor would be detached or thrown
off, which might either retain its form as a nebulous ring, like the
ring of Saturn, or first breaking into fragments, from some want of
continuity in its structure, and afterwards coalescing into one mass,
might be condensed into a planet as the vapor continued to cool. These
rings or planets, thus detached from the central atmospheric mass, would
continue to revolve, in virtue of the force originally impressed upon
them, and their motion would be nearly circular, in the same plane and
in the same direction with that of the sun. The first planet, so
formed, must have been that at the extreme limit of our solar system;
the second the next in point of remoteness from the centre, and so on;
each resulting from the operation of the same natural laws, and emerging
into distinct existence at that precise point in the gradual cooling and
contraction of the atmosphere at which the centrifugal became stronger
than the centripetal force. But each planet might also be subjected to
the same process of cooling and contracting, and might therefore throw
off, under the operation of the same mechanical laws, zones of vapor
more or less dense, which might consolidate into moons or satellites,
and which should also revolve, like the planets, round their primary.
Thus, Uranus has six satellites, and Saturn seven; while the latter has
also thrown off two zones so perfectly uniform in their internal
structure that they remain unbroken, and constitute a double ring around
the planet.

In this _first_ form of the theory, which assumes the existence of the
sun and its