Forms of the Lines of Electric Force. 

 Fig. 1. 



307 



45 



40 l 



35 



30 



2£ 



20" 



\S 



iC) 



i \ 





































1 













n 



Oil I 











M 



ffi 











: \ 













1 

















OC-/3 













2 3 4-5 



2a 



/it up 



V? 



Turning now to arg. >?i, equation (8) with (4) gives 



J (k 2 a) 1 



'. arg. m = -|arg. 



log- . h 2 a . Ji(k 2 a) 

 J (k 2 a) 



^ Jo(ksa) ( 



t log- . k 2 a .J l (k 2 a) ) 



(12) 



