by a Charged Metal Surface. 



439 



supposing a harmonic force acting in the normal direction re- 

 sisting any motion of the corpuscles out of the charge layer. 



If we suppose the forces are periodic and vary as e ipt , we 

 have 



mp 2 ' 



eY 



v = - 



mp 2 



and 



K- 



eZ 



mp' — a' 



as far as the external forces are concerned, we shall therefore 

 have a flux of ions 



dt 



, etc. 



And the equations for the charge layer are 



dX-VL±*x-V ( d — - 9 — ^ \ 

 dt mp \dy dz ) 



dY _ nee 2 _ /d_L_ _ dN_\ 



dt mp \dz doe J i 



dZ _ n'ie 2 p fdM _ dL \ 



dt mp 2 — a 2 \dss dy ) ' 



mp' — a' V ' 



We have also the magnetic equation 

 dH. 



dt 



= —V curl E. 



If we suppose the forces vary as 



gt (lx+my+nz+pt) 



V mpj 

 n'e 2 \ 

 mp] 

 n'e 



we have 



Y [p 



\ mp 



Zip 



mp' - w 



= V(mN-nM) 

 = V(nL -IN) 

 = V(IM -mL) 



•(1), 



P 



and ^(L,M,N) = - (mZ - n Y, nX -IZ,IY- mX). 



We have therefore 



XLl = 

 XLX = 



.(2). 



