174 



L. Page — Relativity and the Ether. 



OP 



equal to - — . Consider three systems, K, K' and K" . K is 



the system for which E is to be determined, and relative to 

 which the charge has a velocity V and an acceleration f at the 



OP 



time earlier than that for which the value of E at P is 



G 



desired. K' is the system of the charged particle when at 0. 

 Without loss of generality w T e can choose axes so that V is par- 



Fig. 2. 



allel to the Z and Z' axes, and f lies in the YZ or YZ' plane. 

 Hence V = V. K" is the system of the charged particle at a 

 time dt after the particle has left 0. K" will have some 

 velocity dV relative to K\ where dV must evidently lie in the 

 Y'Z' plane, y' is the angle between dV and O'Z', 9' that 

 between dV and O'P', and ^ / that between OX and the plane 

 determined by d\l ; and W?'. 



As usual we shall denote the components of dM by d V y and 

 d V z , and those of C by c x , c y , c z . The following relations may 

 be derived from equations (1) and (2) : 



dV = 



*kv i+<i-«(jpfy 



a-/* 9 ) 



