OHM ON THE GALVANIC CIRCUIT. 451 



change in their electroscopic force by the same quantity of elec- 

 tricity, then there would still remain to be added a coefficient y 

 corresponding to this property of the various bodies. Experience 

 has not yet decided respecting this supposition borrowed from 

 the relation of heat to bodies. 



If we assume the two expressions just found for the entire 

 change in the quantity of electricity in the disk M during the 

 moment of time c?^ to be equal, and divide all the members of 

 the equation by w dx dty we obtain 



du d^ u b c , . 



' dt dx^ o> ' ^ ' 



from which the electroscopic force u has to be determined as a 

 function of x and t. 



12. We have in the preceding paragraph found for the change 

 in the quantity of electricity occurring between the disks M' 

 and M during the time d t 



X (u'—u) dt 



and have seen that the direction of the passage is opposed to 

 the course of the abscissae when the expression is positive ; on 

 the contrary, it proceeds in the direction of the abscissae when 

 it is negative. In the same way the magnitude of the transition 

 between the disks M^ and M, when we retain the same relation 

 to its direction, is 



X {u,—u) dt 

 dx 

 If we substitute in these two expressions for u, and u' the trans- 

 formations given in the same paragraph, and at the same time 

 X w for X, i. e. the absolute power of conduction for the relative, 

 we obtain in both cases 



du J. 

 xca -J- dt, 

 dx 



whence it results that the same quantity of electricity which 

 enters from the one side into the disk M during the element of 

 time d t, is again in the same time expelled from it towards the 

 other side. If we imagine this transmission of the electricity, 

 occurring at the time t in the disk belonging to the abscissa x, 

 of invariable energy reduced to the unity of time, call it the 

 electric current, and designate the magnitude of this current by 

 S, then 



