her words, form
themselves into a cluster of stars of almost a globular figure, more
or less regular according to the size and distance of the surrounding
stars....

"The next case, which will also happen almost as frequently as the
former, is where a few stars, though not superior in size to the rest,
may chance to be rather nearer one another than the surrounding ones,...
and this construction admits of the utmost variety of shapes....

"From the composition and repeated conjunction of both the foregoing
formations, a third may be derived when many large stars, or combined
small ones, are spread in long, extended, regular, or crooked rows,
streaks, or branches; for they will also draw the surrounding stars, so
as to produce figures of condensed stars curiously similar to the former
which gave rise to these condensations.

"We may likewise admit still more extensive combinations; when, at the
same time that a cluster of stars is forming at the one part of
space, there may be another collection in a different but perhaps not
far-distant quarter, which may occasion a mutual approach towards their
own centre of gravity.

"In the last place, as a natural conclusion of the former cases, there
will be formed great cavities or vacancies by the retreating of the
stars towards the various centres which attract them."(1)

Looking forward, it appears that the time must come when all the suns
of a system will be drawn together and destroyed by impact at a common
centre. Already, it seems to Herschel, the thickest clusters have
"outlived their usefulness" and are verging towards their doom.

But again, other nebulae present an appearance suggestive of an opposite
condition. They are not resolvable into stars, but present an almost
uniform appearance throughout, and are hence believed to be composed of
a shining fluid, which in some instances is seen to be condensed at the
centre into a glowing mass. In such a nebula Herschel thinks he sees a
sun in process of formation.

THE NEBULAR HYPOTHESIS OF KANT

Taken together, these two conceptions outline a majestic cycle of world
formation and world destruction--a broad scheme of cosmogony, such as
had been vaguely adumbrated two centuries before by Kepler and in
more recent times by Wright and Swedenborg. This so-called "nebular
hypothesis" assumes that in the beginning all space was uniformly filled
with cosmic matter in a state of nebular or "fire-mist" diffusion,
"formle