Double Stars. 135 



yellow, 1855 to 1857. I fancied it, with, a 3-fg- incli object-glass, 

 at one time ruddy, at another bluish, from 1850 to 1855, appa- 

 rently changing even while being looked at ; a versatility of hue 

 which I have remarked in other stars similarly circumstanced, 

 and which, may possibly depend upon unequal sensitiveness to 

 colour in different conditions of the retina ■ during a short 

 glimpse with 5| inches, 1862*57, the companion seemed bluish; 

 at the same time I thought, as I had done in former years, that 

 there was more than \ mag. of difference. Struve gave more 

 than 1 mag. Secchi' s discordances are considerable, ranging 

 between •§■ and 2 mags, from 1855 to 1857; but the honesty of 

 that excellent observer, in recording every temporary impres- 

 sion, must be allowed for. The binary character of this double 

 star, sufficiently evident from the foregoing data, which indi- 

 cated to Smyth a period of not less than 560 years, has been 

 further confirmed by its continued movement, Secchi having 

 found 2"-478 and 1 84°-77, 1857-711. The period, however, re- 

 mains a puzzle. Hind has given 737 years ; Eyre Powell, 240 ; 

 Jacob, 195. " This is certainly," as the Admiral remarks in 

 professional language, " more yawing than might have been 

 looked for ;" and we might still add Madler's 608, and Klink- 

 erfues' 420 years. This beautiful pair is converted into a triple 

 group by the addition, in a far-reaching perspective, of a blue 

 11 mag. star, called 15 or 20 mag.* by South in 1825, and not 

 perceptible to him with a power of more than 92 upon 5 inches 

 of aperture, so that it may possibly be variable. The increase 

 of its distance from 44" in 1839, to upwards of 49", according 

 to Secchi and Madler, in 1855, gives ocular proof of the proper 

 motion of the other two, while its fixed position serves instead 

 of a micrometer, to make their rotation sensible. In 1839 

 the angle between the directions of the two smaller stars was 

 about 56°; a glance at their present position will show that it 

 rather exceeds 90°. In this very interesting and unusual in- 

 stance, angular progress is rendered distinctly perceptible to 

 amateurs unprovided with tne means of measurement, and much 

 more satisfactorily so than by mere comparative estimates from 

 the direction of motion through the field. 



38. v Coronce. 0"-8. 57°-2 (1832-63). 0"-5. 246°-8 

 (1852 "43). White and golden -yellow. The period is stated by 

 Smyth at about 44 years. Yvon Yillarceau prefers 67, but 

 Winnecke finds the observations best represented by 43. What 

 a glorious idea is given to every thoughtful mind of the power 

 of the Creator, and of the infinite variety of his creation, by 

 this rapid revolution of these two magnificent suns ! The object 



* It must however be borne in mind that this observer calls the attendant of 

 Aldebaran 20 mag., which Smyth rates 12, and which Dawes has seen with only 

 2| inches of aperture. 



