766 

 but as 



I I.A.N'D. 1111 NORWEGIAN AURORA POLARIS KXl'F.niTJOX, K)O2 1903. 



V0I" Lcosft) i 



* r 



h {,/,.. 2 A) I'A' -+ A (A' cos /; -|- L\ /, (/. C os ^ + A')./, | 



"i 



; A I A./, - 3 ./,!<,/, . 



I' we desire t' i determine /' ; ,,, \ve must go back to equation (12), from which it is easy to deduce 



/-A'- A^'H , 



(281 



, ' /0 

 xVA'S/ J 



c /' 



1 o d i 

 So 



(cos cos _ cos ,j) r/a 



eVe 



= A + 2 A 



A- 



j \ a >/ : ' L- sin- ,j 



t/i- "".A. 



./ 1 ~ ./-^ ~r i A' cos /; 



2 A A . (/;,. 



(291 



(30) 



\ve obtain, alter some ix-chiction, 



