Spherical Conducting Shell on Dielectric Induction. 163 



P«(0)=Jo(kp), P,|(«)=yJ l (A/), 



c = OD = OM-DM 

 = r— z ultimately ; 



.-. (i J =(l-- r Y=e-**m the limit. 



The successive values of n are 1, 2, 3 . . .; let k + dk be the 

 successive values of k ; 



/. n+L = (k+dk)r; 

 .*. rdk = l i 



.; z ( - )= -dh=dk; 



n + l\r / w + 1 



.-. n = 27r/f e- k2 J {kp)^i(kf)dk. 

 This result can also be deduced from the equation 



d 2 a Ida dm 



dr 2 r dr dz 2 ' 



remembering that 



when 2=0, fl = 27r from r = to r=a. 

 fl = from r — a to r = oo . 



