214 Double Stars. 



6-mag. stars will be seen, followed by two other similar ones. 

 The most n star of the triangle is — 



144. 28 Aquilce. 59"-8. 175°-7. 6 and 10. Dusky white 

 and lilac blue. I noticed a minute pair, perhaps 104 and 

 11 mags., somewhat wider, at a little distance/. 



We must now advance into an intricate and puzzling region, 

 n p Al Tair, where we must " keep a bright look out," or we 

 shall be likely to miss some objects of interest. Few of the 

 stars in this neighbourhood exceed 6 mag., and therefore any 

 dulness of vision or atmosphere will greatly increase our diffi- 

 culty. A careful study of the district with the finder will 

 however enable us in a short time to master it all. We may 

 as well begin with a little group (appearing- as a small vertical 

 pair in the finder), lying about midway between Al Tair and a 

 and /3 Sagittce, as always easy of recognition, from its peculiar 

 character, though the lucida is inferior to several of its neigh- 

 bours : it is also intrinsically a pleasing object, three stars 

 forming a nearly vertical line : the furthest n, 6 mag. according 

 to Star Map, but certainly small for that rating, white ; this 

 is ty Aquilce : — the central star 9 mag., perhaps purplish : — the 

 s, 8 mag., orange or rosy, 255 P. XIX. We will next identify 

 % Aquilce, a yellow star of a good 6 mag., and therefore fairly 

 visible to an ordinary sight ; a line drawn from Al Tair 

 through its conspicuous and well-known 3-mag. companion 

 n p, <y Aquilce, alias Tarazecl, points to it at about an equal 

 distance beyond. Now between this ^, and -ty just mentioned, 

 but a little E. of the line, we find — 



145. 250 P. XIX. Aquilce. 20". 312°. 8^ and 14. White 

 and blue. This pair possesses considerable interest from the 

 probability that the attendant may be variable. Sm. calls it 

 " an excellent test object," but it has certainly ceased to de- 

 serve that appellation, the smaller star now considerably out- 

 shining the comes of 257 P. XIX. (to be described presently as 

 No. 147), which Sm. rates 10 mag. My attention was drawn 

 to its unexpected size by a correspondent in 1862, and Mr. 

 Knott found it, 1862*56, about 10*2, and visible even with 

 1^ inch of his great equatorial. Struve also rates it 9*5, cor- 

 responding to 10J Sm. The possibility of any mistake or 

 misprint in the Bedford Catalogue is obviated by its de- 

 scription as a " test object," which it could not be in any other 

 respect but that of light ; and any suspicion of passing haze 

 at the time is removed by the agreement of Sm.'s estimate of 

 the mag. of A with those of Struve and Knott. It well de- 

 serves, therefore, to be attended to. 



About 1\° E. of x, and forming a tolerably equilateral 

 triangle with % and 7, or ^ and ty, we find — 



146. 7r Aquilce. 1"'7. 121°-3. 6 and 7. Pale white and 



