﻿376 Prof. S. C. Kar on the Eleetrodynamic 



That is, 



q = [^ 1 mV + ^n 2 /H/^H 2 )-o) 1 2 {/ 2 (/c 2 + ^) + m 2 (A-3 + ^ 1 ) 

 4-n 2 (^ 1 -+^)+A ;i /cA} + a) 1 4 {^(l-/3 2 )+^(l- 7 2 ) 

 + /, 3 (1-^)}] 



- : - 2 (l_ a 2_£2_ 7 2_ 2a/ 5 7 ) (»*-**) (tof-CDs 2 ), 



r = [(/^ 2 +/^ 2 + y 2 Hi 2 )- w 2 2 { P fe + y -\-m 2 (h + h) 

 + n 2 ft^/. 2 ) + /^ 2 /^l + a, 2 4 {^(l-/3 2 )+A- 2 (l- 7 2 ) 

 + hil -a 2 )}] 



^2(l-a 2 -6 2 -7 2 -2a y S 7 )(a) 2 2 -a) 3 2 )(co 2 2 -a) 1 2 ), 



+ 72 2 ft + /v 2 ) + Ws} + o) 3 4 {^(l-^ 2 ) +/c 2 (l- 7 2 ) 



+ ^3(l-« 2 )}] 



^2(l-a 2 -/3 2 - 7 2 -2^ 7 ) (» 3 2 -ft>i 2 ) (a) 3 2 -0. 



On inspecting these equations for damping coefficients it 

 is noticed, at once, they are also correct with respect to the 

 dimensions. 



XXXIV. On the Eleetrodynamic Potentials of Moving 

 Charges. By S. C. Kar, M.A., Professor of Mathe- 

 matics, JBangabasi College, Calcutta *. 



THE eleetrodynamic potentials of a moving charge or 

 the electron have been the subject of several in- 

 vestigations and the earliest were those of Lienardf and 

 WiechertJ. Among recent writers who have found the 

 potentials on a relativity basis may be named Sommerfeld§ 

 and M. X. Saha||. Both of these writers performed a four- 

 dimensional integration in the Minkowski space-time mani- 

 fold and have obtained results which are quite general. 

 It appears to the present writer that the Lienard and Wie- 

 chert result — and the method admits of easy extension to 

 the case of a straight linear current — may be obtained easily 

 enough by a Lorentz transformation to a rest-system and 

 back without resort being had to four-dimensional integration. 



* Communicated by the Author. 



f JJ Eelairage electrique, vol. xvi. pp. 5, 53, 106 (1898). 



t Arch. Need. vol. v. p. 549 (1900). 



§ Ann. (I. Phys. vols. Hi. and liii. 



j| Phil. Mag. vol. xxxvii. p. 347 (1919). 



