1865] MACFARLANE — EXTRACTION OF COPPER. 225 



It will be recollected that the experiments just described were 

 made with an ore poor in sulphur ; containing no more of 

 that element in proportion to the copper than is contained 

 in copper pyrites. The results not proving satisfactory, I pro- 

 ceeded to experiment upon ores containing more sulphur, taking 

 care always to keep the temperature very low, and to interrupt the 

 calcination so soon as the developement of sulphurous acid had 

 ceased, and while that of chlorine and other gases was going on. 

 The following are some of these experiments, with their results : 



500 grains ore from Escott, containing 10*4 per cent copper 

 (and both iron pyrites and copper pyrites), were calcined with 500 

 grains of iron oxide and 200 grains of salt. The product weighed 

 1184 grains, and gave with water a solution from which iron pre- 

 cipitated 49*6 grains of copper. Since fifty-two grains were present 

 in the ore operated on, it is evident that 94-2 per cent of the 

 copper was removed in a soluble form. 



500 grains ore from Escott, containing 4-5 per cent of copper, 

 and a considerable amount of iron pyrites, were calcined with 100 

 grains of iron oxide and 100 grains of salt. The result weighed 

 618 grains, and when heated with water yielded a solution contain- 

 ing 22-2 grains copper. 22*5 grains were present in the original ore ; 

 hence 97*7 per cent of the copper was dissolved. 



300 grains of the same Escott ore, with 4-5 per cent of 

 copper, 300 grains of ore from Bruce Mines containing 8*7 per 

 cent of copper (and no iron pyrites), 300 grains of iron oxide, and 

 300 grains of salt, were calcined until chlorine was strongly de- 

 veloped. The result treated with water gave a green solution con- 

 taining thirty-six grains of copper. Since the ore used in this 

 experiment contained 39*6 grains copper, 90*9 per cent of the metal 

 was removed in a soluble state. 



300 grains of Bruce Mine ore of 8*7 per cent, 200 grains of 

 iron pyrites from Brockville, 300 'grains of iron oxide, and 200 

 grains of salt were calcined in the manner above mentioned. The 

 product gave with water a solution containing 27*1 grains copper. 

 The ore contained only 261 grains, and the excess may have been 

 derived from the iron pyrites. In this case, therefore, the whole 

 of the copper of the ore was dissolved. 



The same mixture as the preceding, calcined for a longer time, 

 yielded only 14*5 grains of copper in a soluble state. 



400 grains of Bruce Mine slimes of 54 per cent, 400 grains of 

 iron oxide, 100 grains of pyrites from Brockville, and 100 grains 



Vol. II. p No. 3. 



