comparatively thin cluster of stars, including the sun as one of its
central members. This flat star-cluster is conceived to be moving
edgewise through the chaos, and, according to Professor Comstock, it
acts after the manner of a snow-plough sweeping away the cosmic dust
and piling it on either hand above and below the plane of the moving
cluster. It thus forms a transparent rift, through which we see
farther and command a view of more stars than through the intensified
dust-clouds on either hand. This rift is the Milky Way. The dust
thrown aside toward the poles of the Milky Way is the substance of the
nebulæ which abound there. Ahead, where the front of the star-plough
is clearing the way, the chaos is nearer at hand, and consequently
there the rift subtends a broader angle, and is filled with primordial
dust, which, having been annexed by the vanguard of the star-swarm,
forms the nebulæ seen only in that part of the Milky Way. But behind,
the rift appears narrow because there we look farther away between
dust-clouds produced ages ago by the front of the plough, and no
scattered dust remains in that part of the rift.

In quoting an outline of this strikingly original theory the present
writer should not be understood as assenting to it. That it appears
bizarre is not, in itself, a reason for rejecting it, when we are
dealing with so problematical and enigmatical a subject as the Milky
Way; but the serious objection is that the theory does not
sufficiently accord with the observed phenomena. There is too much
evidence that the Milky Way is an organic system, however fantastic
its form, to permit the belief that it can only be a rift in chaotic
clouds. As with every organism, we find that its parts are more or
less clearly repeated in its ensemble. Among all the strange things
that the Milky Way contains there is nothing so extraordinary as
itself. Every astronomer must many times have found himself marveling