M. B. Riemann on Electrodynamics. 369 



axes, and u\ v', w' in the point (x' } y', z } ), and if r is the distance 

 of the two points, c the constant determined by Kohlrausch and 

 Weber, experiment has shown that the potential of the forces 

 exerted by S upon S' is 



-m 



uu' + VV 1 + ww ! 7C1 ,„, 

 db ab. 



this integral being extended over the whole of the elements dS 

 and dS' of the conductors S and S'. If, for the specific intensi- 

 ties of the current, we substitute the products of the velocities 

 into the specific gravities, and then for the products of these into 

 the elements of volume the masses contained in them, this ex- 

 pression passes into 



_ee'l dd'{r q ) 



22 



cc r dt dt 



if the alteration of r 2 during the time dt, which arises from the 

 motion of e, be denoted by d, and that arising from the motion 

 of e' be denoted by d l . 



This expression, by taking away 



cc r dt 



dt 



which disappears when summed with respect to e, passes into 



^ ee> d \r) <P{t*) . 

 "" cc dt dt ' 



and this again, by the addition of 



d'2,%— rr 



<i) 



cc dt 

 dt 



which by summing with respect to e' becomes null, is changed 

 into 



dd ,(l 



© 



22ee'- 



cc dt dt 



Deduction of this Law from the new Theory. 



According to the current assumption as to electrostatic action, 

 the potential function U of arbitrarily distributed electrical 



