REFINING OF COPPER AND LEAD. 217 



which I have found equal to 80, I obtained the number of 

 calories supplied to the baths by the passage of a current. 

 Multiplying then by the mechanical equivalent of heat, I ob- 

 tained the quantity of work represented by this apparent 

 heat. 



"It will be understood that it is only the apparent and 

 sensible heat of which I have thus been able to calculate the 

 value ; and that the results which I have obtained are inferior 

 to the real figures. 



" Deducting from the total work performed by the motor in 

 each experiment the w r ork corresponding to the friction of the 

 electric machine and to the heating of the liquids, I obtained the 

 quantity which I call remainder in the columns of my tables. 



" In the experiments of the third series (Table No. 2), we 

 have the irrefutable proof of the fact that the expenditure of 

 work with soluble anodes in electrolysis can be taken as nil, for 

 the deposition is seen to pass from 15 to 60 grammes without 

 giving rise to an increase of work which could be measured. If 

 the experiments of Table No. 1 show everywhere a remainder 

 of work the use of which cannot be precisely determined, it 

 must be observed that this remainder grows smaller as I realise 

 some better conditions, and becomes as low as '868 kilogram- 

 metre, and so less than one-sixth of the total work. It is ex- 

 plained by a calorific work in the other parts of the circuit. 



M. BECQUEKEL'S EXPERIMENTS. M. Ed. Becquerel carried 

 out, more than twenty years ago, some very interesting re- 

 searches on the electrolysis of the sulphate of copper, with a 

 view of determining if the quantities deposited on the cathodes 

 exactly corresponded to the quantities dissolved by the anodes. 

 These experiments* have been conducted simultaneously, with 

 the solutions of sulphate of copper sold in the trade, of copper 

 acidulated by means of sulphuric acid diluted to ^ of sulphate 

 of copper crystallised several times, and of sulphate digested in 

 a cold state with carbonate of copper so as to render it neutral. 

 M. Becquerel used a number of Bunsen cells varying from 

 one to ten ; the weights of copper deposited varied from 1 to 15 

 grammes. 



* Elements d'electro-chimie,' by M. Becquerel, edition 1864, p. 220. 



