﻿472 Prof. D. N. Mallik on the 



since , 4-7T (~df B/i 



* ~k \dz--dn) 



co = h + p~, &c. [§ 6] 



Integrating by parts the first integral of (23) and 

 substituting 



47TO) = — — ~ &C. 



in the second integral and again integrating by parts, we 

 set 



•» 





^ + Sf-S 



= ^Jp/rfr+jV(r/-i/3)rfT, . . . (24) 



which may be stated in words as follows : — 



An electron in motion is subjected to a force -which is the 

 sum of an electrostatic force and an electrodynamic force, 

 as the result of the action of the field. [Poincare, ' Elec- 

 tricite et optique.'] 



21. Again, if T 2 be the kinetic energy of free aether, we 

 have 



T,?=J : (Fu+.Gi7 + Hicyif, 



where w=/+A, &c, 



while W = the potential energy 



— j- I (f 2 +g 2 + li 2 )dr, where it should be remembered 



jfc ===^, V being the velocity of light in free aether, and 

 fj g, li are connected by the equation of condition 



Introducing (in the manner oE Larmor) an undetermined 

 multiplier (p and writing 



W '= JfjV f +^ + *Vr-J# [(g + ...)-,]*, 



