Double Stars. 213 



yellow colour — a hue which in a minor .degree predominates in 

 this region, being noticeable in a, (3, y, and t) of this constella- 

 tion,* besides others which come before us as pairs. 8 is also 

 beautifully situated in a rich galaxy region full of glorious com- 

 binations of minute stars. But we are now about to use it as 

 a pointer to the next object, lying a little way nf — 



139. £ Sagittce. 8-6. 312 6 -3. 5 and 9. Silvery or flushed 

 white and cerulean blue ; improving greatly under red illumi- 

 nation. A pretty double star. 



13 and 15 Sagittce (not in Sm.) will both repay the finding, 

 as the centres of fine groups, especially the former, in which 

 the lucicla is of a fine orange, while a smaller one is very red. 



140. e Sagittce. V 32"'2. 80°-9. 6 and 8. Faint j^ellow and 

 bluish. This wide but pleasing object may be found by means 

 of a and /3. 



141. 2 and 3 Sagittce (not in Sm.) These two 6-mag. 

 stars, of which 2 is considerably the larger, form a fine wide 

 pair. Both are white. 



We now proceed into the constellation Aquila. In looking 

 westward from Al Tair, a little n, across the intervening dark 

 space to the p branch of the Milky Way, we see two tolerably 

 conspicuous stars, £ and e Aquilce, both 3 mag. according to the 

 S.D.U.K. sta.r maps, although e seems very small for that mag- 

 nitude. This star is pale orange, £ being pale yellow. In the 

 field with e, sf, but much more s than/, is our next pair — • 



142. 263 P. XVIII. Aquilce. 6"-5. 289°-l. 8* and 10^. 

 Pale yellow and sapphire blue. This pair seems to be only 

 optical: it is called a " handsome test object " by Sm., that 

 is, of course, for the light of smaller instruments. I noticed 

 another star, as minute as the comes, a little way nf. 



A short distance S. of e and W. of £ we shall perceive, in 

 the finder, two small stars. The n of these, 10 Aquilce, 6 mag., 

 is in a remarkable neighbourhood, being closely preceded by a 

 curiously arranged group of small stars, and followed at a 

 greater distance by another scattered group. There is so 

 much similarity of magnitude in these little assemblages as to 

 convey the impression of mutual relation and dependence. 

 The s of the two stars is our next object — 



143. 11 Aquilce. 19"'l. 240°-9. 7 and 10. Pale white and 

 smalt blue (1832-61). I thought A yellow, 1850-7, 1864-76, 

 1865*63. So Dembowski, 1863-48. X called it greenish 

 white, 1831'31. Sm. would have rated A 6 mag., %, 5 - 7, 

 Demb. 5. His measures are 17""427. 252°'15. 



About two-thirds of the distance from Al Tair to £, we 

 shall meet with another pair. In the finder a triangle of 



* It is somewhat remarkable, as Sm. has observed, that so unimportant a 

 group of stars should hare been so early formed into a separate constellation. 



