COEFFICIENTS OF SOLENOIDS. 15 



But -f = ^<^f;^) , whence 



b ^ ^ 4:Ahi~a? a 3a- 



9 





Rememberinof that 



we easily find that 



c'(A' + cr) _ (pv~e,){(pv-e.^ + {pv~e,)} P,(P,+ F^;) 



4:Ari'd' 2 2 



_ jw 2 _ _ {(Ft;-ei) + 2(;? ?;-e2))(e2-e3) ^ _ (P ^ + 2P,)((?2-e3) 

 « "^ 'Sr/ 6 6 



i)t; 2 _ {(pv-e,) + 2(pv-e,)}{e,-e,) _ (P,+ 2P , ){e,-e,) 

 "^ a "^ 3«^ ~ 6 6 



Consequently the first two terms of / in the parenthesis are 



fg., o \ , f go o \ pv â/'(o) 



-~l 2 ■*■ 6 r^ '4W~H^ ^^ 



f go o \ pv ê,"{6) 



The quantities within the parenthesis in (12) and (12') are 



