310 On a method of treating Mineral Sulphurets. 



successive deposits of iron, precipitates all its copper, and 

 passes off in a state of sulphate of iron ; of course the first 

 bath will be the one that will first present a deposition of 

 chemically pure metallic copper in a state of powder, when 

 such is the case, it should be cleaned out, and fresh iron 

 put in. When the next bath is in the same state, the same 

 thing should be done to it, and so one with the rest. 



The ore in the platform need not be thoroughly cleaned 

 away more than once in two or three months. It is neces- 

 sary to remark, that at the bottom of the domed reservoir, 

 there is always a small quantity of water to permit of the 

 absorption of any arsenical or other vapor. 



Note. — The simple plan here proposed of working the sulphurets of copper, 

 would, we conceive, be applicable in a most particular manner to the Kemaon 

 copper mines. These mines are now a very trifling source of revenue, but might be 

 rendered, by the introduction of this method of treating the ore, of very great 

 national importance. Sulphuric Acid, one of the products, is an article which we 

 only require to obtain in India at a cheap rate, in order to give rise to numerous 

 chemical manufactures of which it is the basis, as, for instance, the whole of the 

 manufactured medicines. — J. M. 



