458 THE CANADIAN NATURALIST. [Dec. 



copper from ores containing purple copper or copper pyrites, with- 

 out any admixture of iron pyrites. Although in some respects 

 very successful, these experiments still left much to be wished 

 for. Ores deficient in sulphur could not at all be efficiently 

 treated. Even the pyritous ores required to be mixed with a 

 large quantity of iron oxide in order to the complete removal of 

 the copper. This, although favorable to the extraction, largely 

 increased the bulk of material to be treated, and consequently the 

 cost of calcining. 



While visiting the Bruce and Wellington mines, on Lake 

 Huron, last summer, I was forcibly reminded of the vital impor- 

 tance to them of an easy and economical process for extracting 

 the copper of their ores, which consist, almost exclusively, of 

 copper pyrites in a matrix of quartz. It may be safely assumed 

 that one-fourth to one-third of the copper in these ores is lost in 

 the present system of ore dressing. Of equal importance would 

 such an economical humid process be to the Harvey Hill mines, 

 in Megantic county, Quebec, where the ores are also too poor in 

 sulphur to be advantageously treated by any known extraction 

 process. It occurred to me that the difficulty, caused by the 

 scarcity or absence of sulphur, might be overcome by furnishing 

 the ore with sulphuric acid in the shape of calcined sulphate of 

 iron, giving it at the same time the proper proportion of common 

 salt, from the decomposition of which by the sulphate of iron 

 chlorine might be developed for the formation of proto-chloride 

 of copper. It next occurred to me that on precipitating the 

 copper from the solution of the latter salt by metallic iron, a 

 solution of proto-chloride of iron would result, which, on evapora- 

 tion to dryness, would furnish an effective re-agent for treating 

 fresh portions of ore. And, lastly, it appeared to me, that an 

 easy method of procuring this proto-chloride of iron in the first 

 instance would be to dissolve together equivalent quantities of 

 green vitriol and common salt, crystallise out the sulphate of 

 soda, and evaporate the mother liquor to dryness. The proto- 

 chloride during evaporation might become partially oxidized, but 

 this would not lessen its effectiveness in the proposed application. 



At the first opportunity I proceeded to ascertain by experi- 

 ment, in the laboratory, whether these ideas were capable of being- 

 applied successfully, and the following is an account of some of 

 the trials made. Through the kindness of James Bennetts, Esq., 

 Manager of the West Canada Company's works on Lake Huron, I 



