action. The revelation is full
of significance.

Scarcely less so, although after a different fashion, is the disclosure
on plates exposed by Dr. Max Wolf, with a 5-inch lens, in June, 1891, of
a vastly extended nebula, bringing some of the leading stars in Cygnus
into apparently organic connection with the piles of galactic star-dust
likewise involved by it.[1624] Barnard has similarly found great tracts
of the Milky Way to be photographically nebulous, and the conclusion
seems inevitable that we see in it a prodigious mixed system, resembling
that of the Pleiades in point of composition, though differing widely
from it in plan of structure. Of corroborative testimony, moreover, is
the discovery independently resulting from Gill's and Pickering's
photographic reviews, that stars of the first type of spectrum largely
prevail in the galactic zone of the heavens.[1625] With approach to that
zone, Kapteyn noticed a steady growth of actinic intensity relative to
visual brightness in the stars depicted on the Cape Durchmusterung
plates.[1626] In other words, stellar light is, in the Milky Way,
_bluer_ than elsewhere. And the reality of the primitive character hence
to be inferred for the entire structure was, in a manner, certified by
Mr. McClean's observation that Helium stars--the supposed immediate
products of nebulous matter--crowd towards its medial plane.

The first step towards the unravelment of the tangled web of stellar
movements was taken when Herschel established the reality, and indicated
the direction of the sun's journey. But the gradual shifting backward of
the whole of the celestial scenery amid which we advance accounts for
only a part of the observed displacements. The stars have motions of
their own besides those reflected upon them from ours. All attempts,
however, to grasp the general scheme of these motions have hitherto
failed. Yet they have not remained wholly fruitless. The community of
slow movement in Taurus, upon which Maedler based his famous theory, has
proved to be a fact, and one of very extended significance.

In 1870 Mr. Proctor undertook to chart down the directions and
proportionate amounts of about 1,600 proper motions, as determined by
Messrs. Stone and Main, with the result of bringing to light the
remarkable phenomenon termed by him "star-drift."[1627] Quite
unmistakably, large groups of stars, otherwise apparently disconnected,
were seen to be in progress together, in the same dire