REFINING OF COPPER AND LEAD. 227 



There results from the foregoing calculations that by in- 

 creasing the number of baths and the surface of the electrodes 

 of each bath, the saving of three-quarters of the motive power 

 expenditure can be practically effected. When the fuel is dear 

 it is absolutely necessary to work in this fashion, otherwise the 

 cost of electrolytical refining would render such an operation 

 industrially impracticable. 



CAPITAL ABSOKBED. In order to determine the amount of 

 capital absorbed in an installation of copper refining, we will 

 still take as examples the works of Marseilles, Hamburg, and 

 Birmingham ; not that we know exactly what these installations 

 did cost, as the expenditure must naturally have been consider- 

 able, owing to the fact that at first the work must necessarily 

 have been of an experimental kind. If we consider these 

 factories here it is only because of their importance, and of the 

 system adopted by them for the grouping of their baths, and 

 we will calculate what would be the cost of similar installations. 



One vat of one cubic metre, for refining purposes, cost, 

 empty, about 130 francs, and with the solution of sulphate of 

 copper 200 francs ; this total price is doubled for a 3 cubic 

 metres vat. 



The metallic conductors generally cost 2 '50 francs per 

 kilogramme, 100 kilogrammes per bath of 1 cubic metre should 

 be reckoned upon, which corresponds to an expenditure of 250 

 francs. This expenditure is also doubled in the case of a 

 3 cubic metres bath. 



A good steam engine costs, for 4 to 5 horse-power, about 

 4500 francs ; for 10 to 15 horse-power, about 9500 francs, and 

 for 20 horse-power about 12,000 francs. 



The dynamo-electric machines used for electrolytic purposes, 

 can be valued on a basis of 500 francs per electrical horse- 

 power, which corresponds to 7500 volt-amperes. 



With these particulars we can already condense the costs of 

 first establishment of these three factories. 



The quantity of copper to be refined, which plays the 

 principal part in the absorbed capital, is inversely proportional 

 to the rapidity of the deposition. At Hamburg, in one installa- 

 tion only, there is about 1200 square metres of cathodes and 



Q 2 



