248 STUDIES IN ELECTRO-PHYSIOLOGY: 



terminals of a cell, the difference of potential becomes less 

 than the total E.M.F. observed when the circuit is open. 

 Assuming the current to consist of a series of polarisations 

 and discharges, the chemical affinities or contacts must call 

 up the difference of potential representing the whole E.M.F. 

 after each discharge. The remaining part of the E.M.F. 

 is really present in the liquid of the cell, which offers 

 resistance to the current, and in it the potential follows 

 exactly the same laws as in the solid part of the circuit. 

 To illustrate this we will set off a horizontal line ABC 



JI 



Fig. 139. 



and a vertical line AD, representing the E.M.F. AB is 

 the resistance of the cell (r\ and BC that of the connecting 



arc (R). The line DC will then give us the potential at 

 every point in the circuit. 



If there are several cells in compound circuit, AB 

 represents the total resistance, and AD the total E.M.F. 

 of the battery. The line of potential will not then be 

 DC, but a broken line which rises at each cell. Thus, 

 supposing we have three cells, the line of potential will 

 be given by EF; GH ; KC. (See above.) 



