208 



The Rev. Dr. Robinson on the Constant of Refraction. 



y AndromedcB. 

 Twelve observations (1837. 531) give, 

 *2 = + 41° 30' 34". 54. 

 Precession = + 17".647 ; sec var. = — 0". 260 ; proper motion = — 0".057. 



23 X <^B = — 10".59 

 K = 7.1337 



dvL = 

 dfi, zz 



- 0".46 

 — 0".065 



* Argelander's » . . . = 35". 20 

 Airy, Greenwich, (1836 and 1837,) 34 11 



Mine, . 



, 34". 74 



