times that of the magnitude next brighter. For example, we should
have nearly four times as many stars of the sixth magnitude as of
the fifth; nearly four times as many of the seventh as of the
sixth, and so on indefinitely. Now, it is actually found that
while this ratio of increase is true for the brighter stars, it is
not so for the fainter ones, and that the increase in the number
of the latter rapidly falls off when we make counts of the fainter
telescopic stars. In fact, it has long been known that, were the
universe infinite in extent, and the stars equally scattered
through all space, the whole heavens would blaze with the light of
countless millions of distant stars separately invisible even with
the telescope.

The only way in which this conclusion can be invalidated is by the
possibility that the light of the stars is in some way
extinguished or obstructed in its passage through space. A theory
to this effect was propounded by Struve nearly a century ago, but
it has since been found that the facts as he set them forth do not
justify the conclusion, which was, in fact, rather hypothetical.
The theories of modern science converge towards the view that, in
the pure ether of space, no single ray of light can ever be lost,
no matter how far it may travel. But there is another possible
cause for the extinction of light. During the last few years
discoveries of dark and therefore invisible stars have been made
by means of the spectroscope with a success which would have been
quite incredible a very few years ago, and which, even to-day,
must excite wonder and admiration. The general conclusion is that,
besides the shining stars which exist in space, there may be any
number of dark ones, forever invisible in our telescopes. May it
not be that these bodies are so numerous as to cut off the light