LATITUDE OF THE LICK OBSERVATORY. 121 



PROVISIONAL VALUE OF THE LATITUDE OF THE LICK 

 OBSERVATORY. 



By Professor George C Comstock. 

 Communicatsd by Captain K. S. Floyd, President of the Lick Trustees. 



The following provisional value of the latitude of the Lick 

 Observatory depends upon observations made upon four 

 nights in August, 1886, with the Repsold meridian circle by 

 Professor Geo. C Comstock, assisted by President E. S. 

 Holden, who kindly read the microscopes. All of the stars 

 observed were selected from the star list of the Berliner 

 Astronomisches JaJirhuch, and the latitude depends upon the 

 apparent declinations of the stars as given in that ephe- 

 meris. Both the fixed and the movable circle of the instru- 

 ment were read for each star, and were .separately reduced. 

 The discordances found between the results from the two 

 circles are not greater than may fairly be attributed to 

 division errors; the results from the fixed circle are, how- 

 ever, rather more accordant with each other than are those 

 from the movable circle, indicating either inferior gradua- 

 tion or unstable clamping of the latter. 



Each observed star furnishes a value of the reading of the 

 circles when the telescope is pointed to the celestial equa- 

 tor (technically called an equator point), aiid the mean of 

 all the equator points obtained during a night is taken as 

 the equator point for that night. The circle reading cor- 

 responding to the nadir was obtained at the beginning and 

 end of each night's observations, and the mean of these 

 nadir points is assumed as the nadir point for the night. 

 The agreement of the individual nadir points is fairly satis- 

 factory, the difference between separate determinations 

 upon the same night in no case amounting to as much as 



