﻿470 Prof. D. N. Mallik on the 



16. On this understanding, the so-called electrostatic 

 energy of the aether will he W l5 where 



W 1 = 2 j~t{f+gi> + h*)dT, . . . . (11) 



while the potential energy of the material medium will be W, 

 where 



W= 2 -^\(t7+ff ' + h/)dr, . . . (12) 



while the kinetic energy (T) of a material medium may be 

 taken to be 



^(V+/3*+ 7 ?) ( ?t (13) 



17. From (10) we observe, what is a priori evident, that 

 the total force producing the strained condition of the medium 

 is that due to the free sethereal motion and that due to 

 electronic disturbance. 



From the expression for W and T, (12) and (13), we get y 

 applying S\ (T — W)dr = 0, where 8 is the operator of the 

 calaulus of variation, and remembering 



•*-©-£) <»» 



/;'= v v/o, (is) 



where Y 2 = 7 —. 

 Hence, since 



and 



A=/'+A'=-/+p<r, .... (16) 



±77 "dd* 



V%=vV+v 2 A = V7>i'°|;V^, . • (17) 



or 



P+Jw-^vv-g} .... (i8> 



18. Also from Helmholtz's principle we oet 



- \ u \ fa + rnb + nc) ds = \ (Xdw + Ydy + Zdz), . (19) 



where a, b, c = magnetic induction, 



X, Y, Z = electric force. 



