( 355 ) 

 two positive and two negative, iftlie triangle is impossible. After having 

 niiiKipliod equation (15') by -- and having integrated with respect to 



s from s = to .s- = cc, yon get in the first, case -^, in the second case ; 

 i. e. von luwe in both cases : 



J 



7 



sin .«a .sm sB sin set — = -7 A ? U"/ 



s 4 



That is the required expression for ;.; substituting it in equation 

 (10), we have in the case of surface-charge: 



00 00 



fc Cdx r . . ^ . ds 



(£ z= I — I ftin m Sin s n Sin scT — . . ■ • (i') 







Replacing further a by r in equation (16), we get simultaneously 

 for the integral, contained in (12): 



r 4 rds r 



;. r' dr' = - - 

 J JtJ sj 



Ü 



00 



_ 4 rsi 

 jt J 



_ I — j sin sr' r dr sin sR sin sct = 







° . 7 



.Sin sa — sa cos sa , . as 



sin sR sin set — 



«2 s 



17 



Therefore we can write instead of (12) in the case of bodilij-charge : 



3fc rdr rsinsa — sacossa . . ds 



i I S171 sR sm set — . . • (. i o j 



^'aj RJ 



<p = 



27t'aJ RJ {say s 







It may be remarked, that in my first paper the foregoing equations 

 (17) and (18) appear as primary and the equations (10) and (14) are 

 deducted from them by performing the integration with respect to .9. 



Moreo\er it is probable, that the quantities X and x may be 

 replaced in several other ways by a uniform analytical expression. 



Almost the same formulae stand for the vectorpotential, if the 

 motion is free from rotations. Our deduction proves immediately, that 



it is only necessary, to multiply the integrand by —^, ^t-, meaning 



the value of the velocity i> at the time t—t. If on the contrary 

 the motion is accompanied by rotations, you must add to the part 

 due to translation another part due to rotation, where the quantities 

 ;., y. are to be replaced by some quantities X, x' rather more com- 



