Kl I IM.VO OF COPPER AND LEAD. 203 



Each bath contains 88 anodes and 69 cathodes of equal 

 tut nl surfaces. The anodes are arranged in 22 rows of 4. 

 They are 70 centimetres long, by 15 wide, and 1 (average) 

 thickness. The cathodes are arranged in 23 rows of 3; they 

 are 85 centimetres long, by 18 wide, and 1 millimetre uniform 

 thickness. A calculation shows the double immersed surface of 

 the anodes to be 1200 square metres. The distance between 

 the anodes and the cathodes is 7 centimetres. 



The copper is deposited on the cathode in thick layers, and 

 sufficiently dense to be taken direct to the rolling-mill. The 

 deposit is often detached, which is easily done, and melted 

 again. 



The silver falls to the bottom of the bath in a muddy form, 

 together with the other impurities contained in the copper, and 

 the pieces of anodes and cathodes which may become detached. 



The baths are decanted by means of lead siphons, and the 

 sediments are washed and sieved so as to separate the fragments 

 of copper. The sediments are then melted with some litharge, 

 or simply with a reductive flux. The matter thus obtained is 

 cupelled with some argentiferous lead. 



Tiie liquors of the baths, which have been run into a lower 

 decanting tank, are raised into a higher tank and used again. 

 The raising of the liquors is effected by means of a small and 

 very simple lead injector, which was, we think, invented by 

 M. Thiollier. 



Two. workmen suffice for effecting the whole work, the 

 manipulations being almost nil, and no accidental disarrange- 

 ment in the bath installations or to the dynamo machine need 

 be feared. In the course of five years only two stoppages of 

 any importance took place ; one of them was due to the renewal 

 of the collectors of the Gramme machine; Messrs. Oeschger 

 and Mesdach have since had a spare bobbin made, so as to 

 avoid any possible repetition of a similar stoppage. 



The director of the Biache works, M. Msscart, has carried 

 out some experiments for determining the influence of soluble 

 anodes in the refining of copper by electrolysis. 



The following is a description of the results which he 

 obtained : 



