would no more have been able one and all to pursue a perfectly
straight line than the particles of water in the basin. If a man
should spend his lifetime in filling and emptying such a vessel, it is
safe to say that he would never fail to observe the whirling movement.
As the particles of matter in the nebular mass which was to become a
solar system are inconceivably greater than those of water in the
basin, or those of air in the atmospheric whirl, the chance of the
whirling taking place in the heavenly bodies is so great that we may
assume that it would inevitably occur.

As the vapours in the olden day tended in toward the centre of our
solar system, and the mass revolved, there is reason to believe that
ringlike separations took place in it. Whirling in the manner
indicated, the mass of vapour or dust would flatten into a disk or a
body of circular shape, with much the greater diameter in the plane of
its whirling. As the process of concentration went on, this disk is
supposed to have divided into ringlike masses, some approach to which
we can discern in the existing nebulæ, which here and there among the
farther fixed stars appear to be undergoing such stages of development
toward solar systems. It is reasonably supposed that after these rings
had been developed they would break to pieces, the matter in them
gathering into a sphere, which in time was to become a planet. The
outermost of these rings led to the formation of the planet farthest
from the sun, and was probably the first to separate from the parent
mass. Then in succession rings were formed inwardly, each leading in
turn to the creation of another planet, the sun itself being the
remnant, by far the greater part of the whole mass of matter, which
did not separate in the manner described, but concentrated on its
centre. Each of these planetary aggregations of vapour tended to
develop, as it whirled upon its centre, rings of its own, which in