fact that there are thousands of such nebulae to be discerned at
present through our telescopes. It would be extremely unlikely that
any object could exist without possessing some motion of rotation; we
may in fact assert that for rotation to be entirety absent from the
great primeval nebula would be almost infinitely improbable. As ages
rolled on, the nebula gradually dispersed away by radiation its
original stores of heat, and, in accordance with well-known physical
principles, the materials of which it was formed would tend to
coalesce. The greater part of those materials would become
concentrated in a mighty mass surrounded by outlying uncondensed
vapours. There would, however, also be regions throughout the extent
of the nebula, in which subsidiary centres of condensation would be
found. In its long course of cooling, the nebula would, therefore,
tend ultimately to form a mighty central body with a number of
smaller bodies disposed around it. As the nebula was initially
endowed with a movement of rotation, the central mass into which it
had chiefly condensed would also revolve, and the subsidiary bodies
would be animated by movements of revolution around the central
body. These movements would be all pursued in one common direction,
and it follows, from well-known mechanical principles, that each of
the subsidiary masses, besides participating in the general
revolution around the central body, would also possess a rotation
around its axis, which must likewise be performed in the same
direction. Around the subsidiary bodies other objects still smaller
would be formed, just as they themselves were formed relatively to
the great central mass.

As the ages sped by, and the heat of these bodies became gradually
dissipated, the various objects would coalesce, first into molten
liquid masses, and thence, at a further stage of cooling, they would