WORK ABSORBED IN ELECTROLYSIS. 33 



have to successively determine the calorific work absorbed by 

 the resistance of the complete circuit, the mechanical work 

 absorbed by friction in the different parts of the machine, the 

 work necessary for the transport of the ions in the electrolyte, 

 the loss of work due to the polarisation of the electrodes, and 

 finally, the expenditure of energy due to all the secondary 

 actions taking place in the bath. It is impossible to in- 

 tegrally effect all these calculations ; the work absorbed by the 

 resistance of the circuit can only be approximately estimated, 

 and a coefficient of the mechanical efficiency of the motive 

 power admitted. As to the other causes of losses of motive 

 power, they can be estimated in block in each particular 

 case, according to the magnitude of the electromotive forces 

 used, and to the nature of the secondary actions which are liable 

 to take place ; but these estimations are only endowed with real 

 interest on the condition of their having been preceded by 

 preliminary experiments. 



In order to determine the calorific work of the circuit, it is 

 necessary to know : 



(1) The specific resistance of the electrolyte ; 



(2) The distance between the electrodes ; 



(3) The surface of the anodes and the cathodes ; 



(4) The resistance of the conductors ; 



(5) The internal resistance of the dynamo. 



In the case of a solution of chloride of zinc, we can admit 

 a specific resistance of the liquid equal to 2 14 ohms, which 



corresponds to n nnnn = 0*000214 ohm per square metre (the 

 1UUUU 



specific resistance being that of one cubic centimetre between 

 two parallel faces) for a thickness of one centimetre of the 

 liquid. We can admit that the electrodes are at a distance of 

 1 metre, and that the immersed surfaces of the anodes and the 

 cathodes are respectively of one square metre for 200 amperes. 

 The intensity being 833 amperes, the total surface will be 

 4 '16 square metres. The resistance K" of the liquid can then 

 be calculated by means of Ohm's formula : 



4*16 



