138 Double Stars. 



and a mass of the larger star equal to 2f times that of our Sun. 

 Well may we gaze upon such an object with astonishment and 

 reverence !* 



43. \ OpMucM. !"• 351° -2 (1834-48). l"-2. 15°-5 (1853-25). 

 4 and 6. Yellowish- white and smalt-blue. This fine pair is un- 

 questionably in orbital motion with a period, according to Hind, 

 of about 96 years. Secchr's three measures give, at a mean, for 

 1857'5, 1"*35 and 20 o- l. I divided it with an aperture of 3-/^- 

 inches and a power of 250 in 1856. It may be found by a line 

 from a Herculis to the np star of the two called Yed (see No. 

 15) at about two-thirds of the distance, and should be looked 

 for soon, before it gets near the horizon. 



We proceed to a grand object — 



44. 0' and & Serpentis. 2i'"6. l03 o< 9. 4| and 5. Pale 

 yellow and golden-yellow. This is a superb pair, and one of 

 the finest in its class, and it lies in a glorious field. The mag- 

 nitude of 6 l has been very differently rated, and it should be 

 watched, as pretty certainly variable ; for which its vicinity to 

 6~ affords an unusually favourable opportunity. A line from 70 

 Ophiuchi to Al Tair will pass somewhat above this object, 

 nearly in mid-distance. It lies in the vacant space between 

 the two streams of the Galaxy, and not on the western edge of 

 the eastern stream, where globes and maps usually, if not 

 always, place it. This traditional misrepresentation of a very 

 obvious and well-marked feature must have had its origin and 

 continuance in that idle spirit of unhesitating copying to save 

 trouble, which has been the cause of so much evil in many 

 branches of research, but is especially inexcusable in such an 

 instance as this. In many questions of history and archaeology, 

 reference to original documents may be very inconvenient, per- 

 haps impracticable; but here nothing could have been more 

 easy than that verification which no one seems to have thought 

 it worth while to make. 



A still more brilliant double star is — 



45. a~ and a Gapricorni. 6' 13" - 4. 291°-4. 3 and 4. Pale 

 yellow and yellow ; each with a faint attendant, that of a? (the 

 larger star) being at some distance. There is a 5th most mi- 

 nute star 5" from a", so delicate as to have been caught only 

 once by Smyth in ' ' little evanescent flashes/ 5 with an aperture 

 of 5'9 inches. Sir J. Herschel has thought that it may pos- 



'* There seems to be some peculiarity, hitherto quite unexplained, about the 

 light of this star. The rings which, under a high magnifying power, surround the 

 spurious discs of stars, are commonly accounted for as the result of the "inter- 

 ference of light," on which supposition they would be an invariable phenomenon. 

 Yet Sir J. Herschel says " the rings of this star seem to have something peculiar. 

 They are thin, and extend farther than in general ?" and in another place, 

 "difficult, owing to the rings and appendages. jST.B. — I always find this star 

 difficult from the above cause." 



