Mr. J. Napier on Copper Smelting. 47 



The above table is exceedingly valuable to the chemist and 

 mineralogist, from its exhibiting the various combinations of 

 copper with other matters, and illustrating the chemical action 

 going on in the bowels of the earth ; still tables of this sort are 

 of little use to the mere practical man. The minerals here named 

 and analysed have been carefully selected and freed from every- 

 thing mechanically mLxed ; many of them have been found only 

 in minute quantities, and therefore can form no distinct division 

 or department in the practical operation of smelting ; and whether 

 the peculiar ingredients that give the distinctive character to 

 the mineral be deleterious or otherwise, their separation me- 

 chanically is altogether impracticable. The smelter may be 

 said to have only two classes of ores, those that contain sulphur, 

 and those that contain no sulphur ; however, from the know- 

 ledge that some ores contain matters which make them more 

 fusible than others, and also matters that combine with the cop- 

 per, making it of inferior quality, a more extensive division is ob- 

 served, such as sulphurous ore (copper pyrites), mundicy ores (ores 

 containing mundic or iron pyrites), gray ore, ^m?/ ore (containing tin), 

 &c. Many of these distinguishing characters depend more upon 

 the foreign matters mixed mechanically with the copper mineral 

 than forming a chemical constituent of it; hence the smelter 

 has a far more extensive class of substances to deal with in his 

 practice than is named in the table of copper minerals given above. 



IMetallic minerals or ores are found filling up cracks or fissures 

 of the rocks forming the crust of the earth, and are termed veins. 

 The minerals composing a vein are generally of a great variety 

 of kinds, containing often copper, tin, antimony, bismuth, iron, 

 nickel, cobalt, arsenic, manganese, silver, &c., besides what are 

 termed the earthy minerals or matrix, such as quartz, lime, slate, 

 &c. In mining, the contents of the vein are taken out, so far 

 as it contains any of the metal or metals sought after ; so that 

 what is technically termed a copper ore is often a mixture of 

 evci-ything that the vein contains. And when it is mentioned 

 that the average per cent, of copper in the ores raised in this 

 countiy is 8, it will be seen that the matters mixed with the 

 copper mineral forming the ore must act a prominent part in the 

 smelting operation ; and the action and reaction of these sub- 

 stances, when passing through these operations, must be at- 

 tended to by the practical smelter. 



The principal substance forming the matrix in copper ores is 

 quartz. The relation of this to the other ingredients is the first 

 thing to be considered by the smelter, as it is the first thing to 

 be got quit of; and for this purpose the relation of the four 

 substances, c()p])er, sulphur, iron and quartz, is the leading fea- 

 ture. To give s(Jin(; idea of tlie character of the copper ores in 

 this country in re8])ect to these matters, we ajjjieud the following 

 table of ores from various mines of Cornwall and Devonshire, 

 tested for their smelting quality, which we shall occasionally 

 have to refer to. 



