the Milky Way, where the stars seem actually to be
more closely packed together. This girdle further appears to contain the
greater number of the stars. Arguing along these lines, Professor
Newcomb reaches the conclusion that the farthest stellar bodies which we
see are situated at about between 3000 and 4000 light-years from us.

Starting our inquiry from another direction, we can try to form an
estimate by considering the question of proper motions.

It will be noticed that such motions do not depend entirely upon the
actual speed of the stars themselves, but that some of the apparent
movement arises indirectly from the speed of our own sun. The part in a
proper motion which can be ascribed to the movement of our solar system
through space is clearly a displacement in the nature of a parallax--Sir
William Herschel called it "_Systematic_ Parallax"; so that knowing the
distance which we move over in a certain lapse of time, we are able to
hazard a guess at the distances of a good many of the stars. An inquiry
upon such lines must needs be very rough, and is plainly based upon the
assumption that the stars whose distances we attempt to estimate are
moving at an average speed much like that of our own sun, and that they
are not "runaway stars" of the 1830 Groombridge order. Be that as it
may, the results arrived at by Professor Newcomb from this method of
reasoning are curiously enough very much on a par with those founded on
the few parallaxes which we are really certain about; with the exception
that they point to somewhat closer intervals between the individual
stars, and so tend to narrow down our previous estimate of the extent of
the stellar system.

Thus far we get, and no farther. Our solar system appears to lie
somewhere near the centre of a great collection of stars, separated each
one from the other, on an average, by some 40 billions of miles; the
whole being arranged in the form of a mighty globular cluster. Light
from the nearest of these stars takes some four years to come to us. It
takes about 1000 times as long to reach us from the confines of the
system. This globe of stars is wrapt around closely by a stellar girdle,
the individual stars in which are set together more densely than those
in the globe itself. The entire arrangement appears to be constructed
upon a very regular plan. Here and there, as Professor Newcomb points
out, the aspect of the heavens differs in small detail; but generally it
may