52 Dr. J. N. Kruseman on the Potential of the 



For 6<u: 



00 



. a 







2 V 



/ n O « 



' cos 2 y~ cos^ y 





cos^ 





\ 



/ 2^ 2« 7 

 / cos z ~^r — COS^ y 





. a 

 -sin T 





\ 



/ o 2 a 

 / cos" 1 -^ — cos z -~ 









z* cp^sin \7i -f- L) a — 



/ 9 2 ^ 



/ COs'y— COS^ 



For 6>a: 







cos^ 



2 \ 



/ 8m I- sll, T 





. (X 



~ sm 2 





2 \ 



/ sm 2~ sln 2 





cos^ 





2 A 



/ . 2 . 2 a 

 / sm I" 8 " 1 2 





sm 2 





Zi <p n Sill yii -f- i ) ti 



2A 



/ Sln - 2 ~ Sm 2 



(a) 



<&) 



00 



(<*) 



(«') 



(&': 



00 



(<?) 



Integrating (a) and (c) between the limits and a, (a 1 ) 

 and (c') between the limits a and tt, we have the further 

 formulae : — 



