786 THE POPULAR SCIENCE MONTHLY. 



scope 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 in- 

 volved in its course it bends sharply about 10 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 sur- 

 rounding Maia. Exactly at the point where this curve is trans- 

 formed into a straight line shines a small star ! In view of all 

 the facts the idea would 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. 



The yellow star % 430 has two companions : magnitudes six, 

 nine, and nine and a half, distances 26", p. 55, and 39", p. 302. 

 The star 30 of the fifth magnitude has a companion of the ninth 

 magnitude, distance 9", p. 58, colors emerald and purple, faint. 

 An interesting variable, of the type of Algol, is A, which at 

 maximum is of magnitude three and four tenths and at mini- 

 mum of magnitude four and two tenths. Its period from one 

 maximum to the next is about three days and twenty-three 

 hours, but the actual changes occupy only about ten hours, and 

 it loses light more swiftly than it regains it. A combination 

 of red and blue is presented by <f> (mistakenly marked on map 

 No. 23 as i/f). The magnitudes are six and eight, distance 56", 

 p. 242. A double of similar magnitudes is x, distance 19", p. 25. 

 Between the two stars which the naked eye sees in k is a minute 

 pair, each of less than the eleventh magnitude, distance 5", 

 p. 324. Another naked-eye double is formed by 1 and a , in the 

 Hyades. The magnitudes are five and five and a half, distance 

 about 5' 37". 



The leading star of Taurus, Aldebaran (a), is celebrated for its 

 reddish color. The precise hue is rather uncertain, but Alde- 

 baran is not orange as Betelgeuse in Orion is, and no correct eye 

 can for an instant confuse the colors of these two stars, although 

 many persons seem to be unable to detect the very plain differ- 

 ence between them in this respect. Aldebaran has been called 

 " rose-red," and it would be an interesting occupation for an ama- 

 teur to determine, with the aid of some proper color scale, the 

 precise hue of this star, and of the many other stars which ex- 

 hibit chromatic idiosyncrasy. Aldebaran is further interesting 



