Mr. J. Napier on Copper Smelting. 49 



contents of the vein are crushed and mixed, they assume a same- 

 ness of character. Many of them contain lime, alumina, and some 

 other earths ; most of them contain antimony ; some of them 

 tin, arsenic, manganese, &c., all of which play an important part 

 in the after operations. There are also a gi'eat many other ores 

 not referred to in the above table, all of which, when mixed, as 

 they must be in smelting, exhibit the same general chai'acter. 



Besides these ores of Cornwall and Devonshire, great quan- 

 tities come from Ireland and different parts of Wales : and 

 vast quantities are also imported from other countries, all of 

 which coming into the smelting-house to be worked up together, 

 must be taken into account in the general description ; and as 

 many of the foreign ores are very rich in copper, more so than it 

 is found oeconomical to work by the ordiuaiy process of smelting, 

 the smelter is thus not only enabled, but somewhat necessitated, 

 to buy poor ores to mix with and dilate these rich ones. Thus 

 ^'ery poor ores in this country, which might otherwise have been 

 unsaleable, are required j so that the importation of rich ores is 

 not, as has been often asserted, destructive to our poor mines. 



Phil. May. S. 4. Vol. 4. No. 23. July 1852. 



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