OBSEKVATIONS WITH THE ZENITH TELESCOPE. 



293 



The reduction for proper motion is the second term in each of the ahove expressions. 

 For example, for Declination 80° 



!' N = '\ -|- .00119 (2'— 1875) 



'"' N ''[ + .0045 (2'— 1875) 



?' B = fi ' A H .0030 (2'— 1875) 



The results of a direct comparison of the stars common to the catalogues of New- 

 comb and Auwers will be found in No. 3742, Astronomisehe Nachrichten, in an article 

 by Dr. Fritz Colin entitled " Vergleichung des Newcomb'schen Fundamenentalcatalogs 

 mit deni A.uwers'schen A. G. C." 



In the pages which follow the column headed 11. A. C. gives the number corresponding 

 to the star's place in the British Association Catalogue, with the exception of five not 

 found in that publication. The magnitudes are from various sources and do not claim 

 great precision. Tin; column beaded A gives the number of authorities employed in 

 deducing the corresponding coordinate. Where N or D occurs in this column it im- 

 plies that the corresponding coordinate is taken from Newcomb or Davis, as the case 

 may be. 



The differential coefficients include the proper motions ^ and p' in accordance with 

 the formuhe given on page 287. 



To illustrate the reduction to any epoch, let the Right Ascension and Declination of 

 No. 3 be required for 1755 : 



.1755— 1875 = — 120 



Therefore 



a lm = 0" 10'" 83».963 - 120 X 3MU89 + i (120) 2 X 0».0002G43 + 0».019 X (- 1.20) 3 . 



— 0" 4"'22 a .01(> 

 (5 m8 = 37" 59' 14". 89 — 130 X 20". 0272 + i (120) 2 X (— 0".000295) — 0».175 X (— 1.S0) 8 



= 37° 19' 9". 80 



Auwers' Bradley gives 



a — 0" 4 1 " 22 s . 08 

 (5 = 370 19' 10".() 



A. P. 



-VOE. XX. IX. 



