230 ELECTROLYSIS. 



case of a rapid and persistent decline in the prices the large 

 stocks may involve some important losses; that is why an 

 interest of 5 per 100 must be maintained every year in view of 

 an abnormal situation which rarely occurs. 



We can estimate the cost of fuel at 20 francs per ton, 

 although that price would be too high in the case of Birmingham, 

 sufficiently approximate for Hamburg, and quite insufficient for 

 Marseilles. However, as we are only making a comparison we 

 will maintain a uniform price ; it will always be easy afterwards 

 to recalculate the cost, taking as a basis the actual cost of fuel 

 in the locality considered. 



An engine of 4 to 5 horse-power consumes 20 kilogrammes 

 of fuel per hour ; the wages of the driver being estimated at 60 

 centimes per hour, and the accessory expenses of waste, 

 grease, &c., at 40 centimes per hour, the total hourly cost of the 

 motive power is therefore 1 60 franc approximately. 



A 20 horse-power engine consumes 50 kilogrammes of fuel 

 per hour ; the driver's wages being 70 centimes per hour, and 

 the accessory expenses 60 centimes. Total, 2 30 francs per hour. 



The cost of maintenance and the wear and tear of the 

 apparatus in use represent a minimum of 10 per 100 of the 

 purchase price ; those of the buildings 5 per cent. The electric 

 conductors, which convey the current in the baths, do not alter 

 in price. Although the market price may fluctuate we cannot 

 introduce such variations into our calculations. 



The labour, in a factory of 40 baths, amounts to 75 centimes 

 per hour, or 18 francs per day ; it is double this amount in a 

 factory of 120 baths. 



The general expenditure can be estimated at 100 per 100 

 of the cost of labour in large installations of 200 to 300 baths 

 for example, and at 150 per 100 of the cost of labour in instal- 

 lations of only 40 to 50 baths. 



The preceding figures will enable us to establish a com- 

 parative table of all the expenses necessitated by the electro- 

 lytical refining of copper. 



We cannot too much insist that these figures are not 

 absolute ; they however are sufficiently approximative for serving 

 as a basis to a project. They convey an exact idea of the ele- 



