536 Mr. Gr. H. Livens on the Electron Theory 



determined by the corresponding components o£ the vector J 

 where 



2qeJ 



ma- I 





1 r W), 



1 2 



+ 



mc 



(hi) 



(^[HE]-t[HV]A) 



+ 



r (H-)i 



lC- [HV]9 K 



whilst the vector W is determined by 



6 



[(•4)K)-*:!-Sg-») 





wc 



I'K) 



(-1), 



H(«" [HE] -i [HVIA 



K) 



2\? 



[HV]? 



These expressions are quite general to the order of 

 approximation adopted, and by applying them to the four 



