﻿468 Prof. D. N. Mallik on the 



11. On comparing the equations (1) and (3), we readily 

 see that these cannot be, obviously, satisfied at the same time 

 if/, <7, /* are to have the same meaning in both. 



12. Now if /> = 0, that is in free cether, 



"das B.y ' "ds 

 Thus, we may say that in free aether, 



that in a material medium, 



while in all cases, 



B/o , B/7o , 3^o 



where / , # > ^o are defined by the equation (4) and are equal 

 to /", </, A, when the medium is free aether. 



13. In order to specify these quantities further, we observe 

 that from the equations 



M + ^ + |*?=0, .... (4) 

 dx oy d- 



and d f ^q ~dh . Q . 



we may write / =/-}-A, &c, (5) 



where W BB BC , a . 



^ + w + ^ = ~ p ■ ■ ■ (G) 



14. This expression suggests that A, B, C are components 

 of a quantity I which corresponds to the coefficient of mag- 

 netization on the usual theory of magnetism, so that just as 

 dM = magnetic moment of an elementary magnet = Idr 

 (where dr is an element of volume), similarly, we may take 

 dM = electric moment of an element of volume containing 

 electrical charges arising from the presence of electrons and 



dM=Idr, (7) 



where, of course, 1= (A, B, C). 



15. Again, from (5), we get 



f»=f+ A (8) 



