r wanting, occur
in numbers so moderate as to lead us irresistibly to the conclusion that
in these regions we are _fairly through_ the starry stratum, since it is
impossible otherwise (supposing their light not intercepted) that the
numbers of the smaller magnitudes should not go on increasing _ad
infinitum_.

In such cases, moreover, the ground of the heavens, as seen between the
stars, is for the most part perfectly dark, which again would not be the
case if innumerable multitudes of stars, too minute to be individually
discernible, existed beyond. In other regions we are presented with the
phenomenon of an almost uniform degree of brightness of the individual
stars, accompanied with a very even distribution of them over the ground
of the heavens, both the larger and smaller magnitudes being strikingly
deficient. In such cases it is equally impossible not to perceive that
we are looking through a sheet of stars nearly of a size and of no great
thickness compared with the distance which separates them from us. Were
it otherwise we should be driven to suppose the more distant stars were
uniformly the larger, so as to compensate by their intrinsic brightness
for their greater distance, a supposition contrary to all probability.

In others again, and that not infrequently, we are presented with a
double phenomenon of the same kind--_viz._, a tissue, as it were, of
large stars spread over another of very small ones, the intermediate
magnitudes being wanting, and the conclusion here seems equally evident
that in such cases we look through two sidereal sheets separated by a
starless interval.

Throughout by far the larger portion of the extent of the Milky Way in
both hemispheres the general blackness of the ground of the heavens on
which its stars are projected, and the absence of that innumerable
multitude and excessive crowding of the smallest visible magnitudes, and
of glare produced by the aggregate light of multitudes too small to
affect the eye singly, which the contrary supposition would appear to
necessitate, must, we think, be considered unequivocal indications that
its dimensions, _in directions where those conditions obtain_, are not
only not infinite, but that the space-penetrating power of our
telescopes suffices fairly to pierce through and beyond it.

It is but right, however, to warn our readers that this conclusion has
been controverted, and that by an authority not lightly to be put aside,
on the groun