70 



Rutherfurd Photographic Measures of 





Orientation 



Plate. 



Variation. 



I 



+ o'l3" 



2 



+ I o 



3 



+ o 6 



4 



— o 35 



5 



— o 8 



6 



+ o 17 



7 



+ 3 21 



8 



O 12 



9 



— o 30 



IO 



2I 



ii 



— O 31 



12 



-+- O II 



13 



+ 24 



15 



O ig 



16 



O 29 



3 7. 



— 2 5 



' 18 



— O 50 



19 



— O 1 



20 



+ 14 



22. In column eight of Table VI are given the parallax coeffi- 

 cients. They have been computed by the formulae : 



where 



S s P 3 + S 9 P 

 fcosec 1 



S R = 



28. // OI24 



g cosec i // 

 28. "0124 



1 



S 6 cos (ir + F) 

 S 6 cos («■ + G) 



and where f, g, F, G, P 3 , and P 4 have the same meaning as in 

 paragraph 14. The value of the position-angle used here, w, is the 

 angle p corrected for proper motion and orientation variation. 

 The quantities S 8 , S 9 , and S 6 are in columns four and five of 

 Table VIII and five of Table VII respectively. P 3 and P 4 are 

 tabulated in paragraph 14. 



23. After adding to the observed angle the correction 



(s s p 3 + s 9 p±) 11 



taken from Table XI with the parallax coefficient of column eight, 

 Table VI, as the argument we have the final corrected angle given 

 in the last column of Table VI. 



