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



205 



24 X c?R = — 32".38 

 K= 6.1247 



dR= — I". 35 

 rf/i= — 0".220 



Precession = 



/i Urscs Majoris. 

 Ten observations (1838. 235) give, 

 8=+42°21'4". 05. 

 — 17".877 ; sec var. = — 0".236 ; proper motion = — 0".015. 



