s us to see.
One may derive much pleasure from a study of the various groupings of
stars in the Pleiades. Photography has demonstrated, what had long been
suspected from occasional glimpses revealed by the telescope, that this
celebrated cluster of stars is intermingled with curious forms of
nebulae. The nebulous matter appears in festoons, apparently attached to
some of the larger stars, such as Alcyone, Merope, and Maia, and in
long, narrow, straight lines, the most remarkable of which, a faintly
luminous thread starting midway between Maia and Alcyone and running
eastward some 40', is beaded with seven or eight stars. The width of
this strange nebulous streak is, on an average, 3" or 4", and there is,
perhaps, no more wonderful phenomenon anywhere in celestial space.
Unfortunately, no telescope is able to show it, and all our knowledge
about it is based upon photographs. It might be supposed that it was a
nebulous disk seen edgewise, but for the fact that at the largest star
involved in its course it bends sharply about 10 deg. out of its former
direction, and for the additional fact that it seems to take its origin
from a curved offshoot of the intricate nebulous mass surrounding Maia.
Exactly at the point where this curve is transformed into a straight
line shines a small star! In view of all the facts the idea does not
seem to be very far-fetched that in the Pleiades we behold an assemblage
of suns, large and small, formed by the gradual condensation of a
nebula, and in which evolution has gone on far beyond the stage
represented by the Orion nebula, where also a group of stars may be in
process of formation out of nebulous matter. If we look a little farther
along this line of development, we may perceive in such a stellar
assemblage as the cluster in Hercules, a still later phase wherein all
the originally scattered material has, perhaps, been absorbed into the
starry nuclei.

[Illustration: THE CHIEF STARS IN THE PLEIADES.]

The yellow star Sigma 430 has two companions: magnitudes six, nine, and
nine and a half, distances 26", p. 55 deg., and 39", p. 302 deg.. The star 30 of
the fifth magnitude has a companion of the ninth magnitude, distance 9",
p. 58 deg., colors emerald and purple, faint. An interesting variable, of
the type of Algol, is lambda, which at maximum is of magnitude three and
four tenths and at minimum of magnitude four and two tenths. Its period
from one maximum to the next is about three days