ELECTROMOTIVE FORCES iX THE VOLTAIC CELL. 



517 



function, for simplicity, until forced to try something more complex. Ifc 

 is quite impossible that /(C) can be a linear function really, but it very 

 likely begins by being so, and only for big currents diverges notably. A 

 hyperbolic tangent function, at a guess, would seem most likely to repre- 

 sent the case properly. 



Elcctwmotiue force of a zinc-zinc, dilute siilj^huric acid, cell; of resistance -J 

 ohm, throiKjh ivJiich the specified currents are driven hy two or three Groves. 

 Each flate exposing 53 square centimetres on each face. 



The agreement between the observed and calculated columns is not 

 very bad, and the polarisation E.M.F. does not show decided signs of 

 breaking away from the law of simple pi'oportion until a current strength 

 of 4 amperes is reached ; say an intensity of 'O'i amperes per sq. centi- 

 metre of total surface. 



Electromotive force of a zinc-copper, dilute siilpJmric acid, cell ; of resistance 

 -1- ohn, tliroiigh vjhich the specified currents are driven hi/ two or three 

 Groves. Each plate exposing 53 square centimetres on each face. E.M.F. 

 rechoned positive 7vhen it helps the current forward, negative lohen it 

 opposes it. 



