VARIABLE STARS. 239 



to me too considerable to be ascribed merely to errors of 

 observation. 



(13) Aquarii R, R. A. 354 11', Decl. 16 6'. 



(14) Serpentis R, R. A. 235 57', Decl. + 15 36'. 



(15) Serpentis S, R. A. 228 40', Decl. -f 14 52'. 



(16) Cancri R, R. A. 122 6', Decl. + 12 9'. 



Of these four stars, which have been but very slightly ob- 

 served, little more can be said than what is given in the table. 



(17) a Cassiopeia, R. A. 8 0', Decl. + 55 43'. This star 

 is very difficult to observe. The difference between its 

 maximum and minimum only amounts to a few gradations, 

 and is, moreover, as variable as the duration of the period. 

 This circumstance explains the varying statements on this 

 head. That which I have given, which satisfactorily repre- 

 sents the observations from 1782 to 1849, appears to me the 

 most probable one. 



(18) a Orionis, R. A. 86 46', Decl. + 7 22'. The varia- 

 tion in the light of this star likewise amounts to only four 

 gradations from the minimum to the maximum. For 91^ 

 days it increases in brightness, while its diminution extends 

 over 104 1, and is imperceptible from the twentieth to the 

 seventieth day after the maximum. Occasionally its varia- 

 bility is scarcely noticeable. It is a very red star. 



(19) a. Hydra?, R. A. 140 3', Decl. 8 1'. Of all the 

 variable stars, this is the most difficult to observe, and its 

 period is still altogether uncertain. Sir John Herschel sets it 

 down at from twenty-nine to thirty days. 



(20) H Auriga?, R. A. 72 48', Decl. + 43 36'. The 

 alternation of light in this star is either extremely irregular, or 

 else, in a period of several years, there are several maxima and 

 minima a question which cannot be decided for many years. 



(21) Geminorum, R. A. 103 48', Decl. + 20 47'. 

 This star has hitherto exhibited a perfectly regular course in 

 the variations of its light. Its brightness at its minimum keeps 

 the mean between v and v of the same constellation ; in the 

 maximum it does not quite reach that of x. It takes 4d. 21h. 

 to attain its full brightness, and 5d. 6h. for its diminution. 



(22) Pegasi, R. A. 344 7', Decl. + 27 16'. Its period 

 is pretty well ascertained, but as to the course of its variation 

 of light nothing can as yet be asserted. 



(23) Pegasi R, R. A" 344 47', Decl. -f- 9 43'. 



