400 ELECTKOKINETICS. [PT. II. CH. X. 



207. Method of Cohn and Arons. Consider a condenser 

 A, which may or may not be connected in parallel with the con- 

 denser B and the resistance wire R. Let the capacity of A be K, 

 the inductivity of the dielectric p. Let the conductivity of the 

 dielectric in A be X and in B zero. Then the charge of one of the 

 plates 1 of A is in terms of the induction, 182 (16), 



(8) ej = 7- 1 1 ( cos (nx) + g) cos (ny) + 3 cos (nz)) dS. 



8 t 



On the other hand the quantity flowing through the dielectric in 

 the condenser in unit time is 



(9) . - 1 = M [u cos (nx) + v cos (ny) + w cos (nz)} dS, 



Si 



so that, assuming X and p constant, 



(10) 



If we assume that an electromotive force is applied to the 

 plates in order to establish a steady difference of potential F 

 until a steady state of flow is attained, we have everywhere in 

 the dielectric p = 0. If the electromotive force is suddenly re- 

 moved, we have from that time on 



and accordingly the difference of potential of the condenser plates 

 is 



di) F=F O *~'. 



If the difference of potential F can be measured by an electro- 

 meter at any time t, we have 



ii t. 



(12) T 



If in the second place the condenser A is connected in parallel 

 with the condenser B and wire of resistance R, we have for the 

 charge e, f of the plate 1 of B, e^ = K'V where K' is the capacity 

 of B. 



