222 



ELECTROLYSIS. 



which we have given the deposits vary between -0001 and *1220 

 millimetre per hour and comprise all the possible applications. 

 In conclusion, we have calculated the thicknesses of the 

 depositions which could be obtained per week of 156 hours 

 with the ten cases which we have described, and the following 

 are the results which we arrived at : 



THICKNESSES OF COPPER DEPOSITED IN 156 WORKING HOURS. 



Experiments and Applications. 



Thicknesses in Millimetres. 



Experiments of M. Gramme 



Mr. Sprague .. 



Works of Messrs. Oeschger and Mesdac i 

 The Norddeutsche Affinerie 



M. Hilarion Roux 



The Elliott Metal Co 



M. Michel, Paris 



Maximum regimen, chemically pure anodes 



0156 to -624 



Good deposit : -468 to 5 '616 

 Bad deposit: 11 to 19 

 468 

 468 

 156 

 178 

 MM 

 3-12 

 1-68 



It has been established from chemical analyses, that the 

 purity of the copper electrolytically obtained, depends upon 

 the distance between the anodes and their cathodes, upon the 

 continuity of the operation, the composition of the baths and 

 the nature of the foreign substances contained in raw copper ; 

 but that it is not altered, all things being equal, when not more 

 than 2 millimetres thickness per week are deposited with a 

 normal regimen. In this respect the works of Hamburg, 

 Marseilles, and Birmingham show no real superiority over each 

 other. 



SPECIFIC EESISTANCE OF THE BATHS. The electromotive 

 force required for the electrical refining of metals, is, in a great 

 proportion, absorbed by the resistance of the baths, which re- 

 sistance depends on the degree of concentration of the baths, 

 their temperature and the distance of their electrodes. 



Numerous experiments have demonstrated that the best 

 solution to employ in the electro 1 ytical refining of copper is one 

 at 16 to 18 Baume. 



This solution corresponds to 18*267 per 100 in weight of 

 S0 4 Cu 5HO. 



