Continuing his observations of the innumerable nebulae,
Herschel is led presently to another curious speculative
inference. He notes that some star groups are
much more thickly clustered than others, and he is led
to infer that such varied clustering tells of varying
ages of the different nebulae. He thinks that at first
all space may have been evenly sprinkled with the
stars and that the grouping has resulted from the
action of gravitation.

"That the Milky Way is a most extensive stratum of
stars of various sizes admits no longer of lasting doubt,"
he declares, "and that our sun is actually one of the
heavenly bodies belonging to it is as evident. I have
now viewed and gauged this shining zone in almost
every direction and find it composed of stars whose
number ... constantly increases and decreases in proportion
to its apparent brightness to the naked eye.

"Let us suppose numberless stars of various sizes,
scattered over an indefinite portion of space in such
a manner as to be almost equally distributed throughout
the whole. The laws of attraction which no doubt
extend to the remotest regions of the fixed stars will
operate in such a manner as most probably to produce
the following effects:

"In the first case, since we have supposed the stars
to be of various sizes, it will happen that a star, being