OHM ON THE GALVANIC CIRCUIT. 467 



M = — O + C, 



which indicates that the electroscopic force in the whole extent 

 of each other homogeneous portion of the circuit is everywhere 

 the same, and merely changes suddenly from one part to the 

 other to the amount of the entire tension prevailing at its place 

 of contact. 



To determine the constant c in this equation, we will suppose 

 the electroscopic force, at anyone place of the circuit, to be given. 

 If we call this u, and the sum of the tensions there abruptly 

 passed over by the abscissa O', we have 



m_m'=_(0-0'). 



The difference of the electroscopic forces of any two places of 

 an open circuit, i. e. a galvanic circuit interrupted by a non- 

 conductor, is consequently equal to the sum of all the tensions 

 situated between the two places, and the sign which has to be 

 placed before this sum is always easily to be determined from 

 mere inspection. 



20. We will now notice another peculiarity of the galvanic 

 circuit, which merits especial attention. To this end let us 

 keep in view exclusively one of the homogeneous parts of the 

 circuit, and imagine, for the sake of simphcity, the origin of 

 the abscissae placed in one end of it, and the abscissae directed 

 towards the other end. If we designate its reduced length by 

 A, and the reduced length of the other portion of the circuit by 

 A, then 



within the length A; the following form may also be given to 



this equation : 



Ax 



A +x 

 u = — - — -y + c', 



ei.^<u^ ... 



the O j ttont is consequently similarly circumstanced to a simple 



Ax 



homogeneous circuit, at whose ends the tension -r occurs. 



If, accordingly, A has a very sensible value, such as it can 

 acquire in the voltaic pile, and if the ratio -r approaches 



A X 

 to unity, then the tension -r will likewise be still very per- 



