1885.] of 'polarization of light by a moving medium. 251 



Then the equations, which give p, q, r in terms of u, v, w, 

 w l} co 2 , co 3 are 



p = u + (o 2 z — w 3 y (1), 



q = v + co.jx — oi x z (2), 



r = w + oj^y — w % x (3). 



The equations of the electromagnetic field are 



*-*-*-%-£ » 



^ dG dyjr /-, N 



Q = 0r _g,____ (,), 



^-aS-f-f (0. 



a== dH_dG (7) 



dy dz 

 h = dF_dH 



dz dx 

 == dG_dF (Q) 



dx dy 



and if the only currents which exist in the medium are displace- 

 ment currents, we have 



. df dc db /1AX 



w n t =a y -dz (10) ' 



. da da dc ,,, N 



. dh db da ,-. nN 



^Tt = dx-dy (12)> 



Since P = ~K-f> ^ = x g ' R ^~x h ' 



we get if we differentiate (4) with respect to y, (5) with respect 

 to z and subtract 



4-7T (Y7/" cfo] [ d d d\ dc . 



xl4-^H^+^ + ^ c+o ^~ K+ *--- < 3) - 



Similarly 



bn-tdk df] [ d d d\ -. , c?6 n * 



