468 THE POPULAR SCIENCE MONTHLY. 



is of a delicate blue color, and it has been suspected of varia- 

 bility. That it may be variable is rendered the more probable by 

 the fact that in the immediate neighborhood of k there are three 

 undoubted variables, S, T, and U, and there appears to be some 

 mysterious law of association which causes such stars to group 

 themselves in certain regions. None of the variables just named 

 ever become visible to the naked eye, although they all undergo 

 great changes of brightness, sinking from the eighth or nintli mag- 

 nitude down to the thirteenth or even lower. The variable R, 

 which lies considerably farther west, is well worth attention be- 

 cause of the remarkable change of color which it sometimes ex- 

 hibits. It has been seen blue, red, and yellow in succession. It 

 varies from between the sixth and seventh magnitudes to less than 

 the thirteenth in a period of about two hundred and forty-two 

 days. 



Not far away we find a still more curious variable C ; this is 

 also an interesting triple star, its principal component being a little 

 under the third magnitude, while one of the companions is of the 

 seventh magnitude, distance 90", p. 355, and the other is of the 

 eleventh magnitude or less, distance 65", p. 85. We should hardly 

 expect to see the fainter companion with the three-inch. The 

 principal star varies from magnitude three and seven tenths 

 down to magnitude four and a half in a period of a little more 

 than ten days. 



With the four or five inch we get a very pretty sight in 8, 

 which appears split into a yellow and a purple star, magnitudes 

 three and eight, distance 7", p. 206. 



Near 8, toward the east, lies one of the strangest of all the nebulae. 

 (See the figures 1533 on the map.) Our telescopes will show it to 



us only as a minute star surrounded with a 

 nebulous atmosphere, but its appearance with 

 instruments of the first magnitude is so aston- 

 ishing and at the same time so beautiful that 

 I can not refrain from giving a brief descrip- 

 tion of it as I saw it in 1893 with the great 

 Lick telescope. In the center glittered the 

 star, and spread evenly around it was a circu- 



WONDERFUL NeBULA IN, ,, ,., -, , ,-,. - 



Gemini (1532). l^-i* nebulous disk, pale yet sparkling and con- 



spicuous. This disk was sharply bordered by a 

 narrow hJack ring, and outside the ring the luminous haze of the 

 nebula again appeared, gradually fading toward the edge to in- 

 visibility. The accompanying cut gives but a faint idea of this 

 most singular nebula. If its peculiarities were within the reach 

 of ordinary telescopes, there are few objects in the heavens that 

 would be deemed equally admirable. 



In the star -q we have another long-period variable, which is 



