304 Intelligence and Miscellaneous Article*. 



we get, as the resultant values of the components produced by the 

 displacements assumed, 



G-a = ^(E 2 — a 2 ) cos a sin a cos e, 



H d = J£_ (E 2 — a 2 ) cos a sin « sin e , 

 which, however, do not satisfy the condition 



du dy dz 



Xow it is very easy to calculate the action of the superficial 

 moving electricity if it be assumed to act like an electric current. 

 Each element of the surface will act as if it had an electric c . p on 

 it: and the.r components of the electromagnetic potential will evi- 

 dently be tbe same as the electrostatic potential, while the y and 

 z components will vanish. Hence 



F c =«p, G c =H c = 0. 



My assumption is that the complete components are 



F=F e -fr d , G = G C + G d , H = H C + H d; 



and it is easy to see that they can be put into the form 



6 } dxdz E ' 



and these satisfy the condition 



cTF clG dR =0 

 dm dy dz 

 These may be further simplified by assuming a function 



X 2 l +f ' dxjR' 



F=- 



E dx 



Gr= 



di/ 



H=- 



c k 



dz' 



