ence in nearly the same region of space,
reiterated and reinforced with others by Mr. Spencer, was urged with his
accustomed force and freshness by Mr. Proctor. It is unanswerable. There
is no maintaining nebulae to be simply remote worlds of stars in the face
of an agglomeration like the Nubecula Major, containing in its
(certainly capacious) bosom _both_ stars and nebulae. Add the facts that
a considerable proportion of these perplexing objects are gaseous, and
that an intimate relation obviously subsists between the mode of their
scattering and the lie of the Milky Way, and it becomes impossible to
resist the conclusion that both nebular and stellar systems are parts of
a single scheme.[1614]

As to the stars themselves, the presumption of their approximate
uniformity in size and brightness has been effectually dissipated.
Differences of distance can no longer be invoked to account for
dissimilarity in lustre. Minute orbs, altogether invisible without
optical aid, are found to be indefinitely nearer to us than such radiant
objects as Canopus, Betelgeux, or Rigel. Moreover, intensity of light is
perceived to be a very imperfect index to real magnitude. Brilliant suns
are swayed from their course by the attractive power of massive yet
faintly luminous companions, and suffer eclipse from obscure
interpositions. Besides, effective lustre is now known to depend no less
upon the qualities of the investing atmosphere than upon the extent and
radiative power of the stellar surface. Red stars must be far larger in
proportion to the light diffused by them than white or yellow
stars.[1615] There can be no doubt that our sun would at least double
its brightness were the absorption suffered by its rays to be reduced to
the Sirian standard; and, on the other hand, that it would lose half its
present efficiency as a light-source if the atmosphere partially veiling
its splendours were rendered as dense as that of Aldebaran.

Thus, variety of all kinds is seen to abound in the heavens; and it must
be admitted that the consequent insecurity of all hypotheses as to the
relative distances of individual stars singularly complicates the
question of their allocation in space. Nevertheless, something has been
learnt even on that point; and the tendency of modern research is, on
the whole, strongly confirmatory of the views expressed by Herschel in
1802. He then no longer regarded the Milky Way as the mere visual effect
of an enormously ext