10 Macfarlane on the Primitive Formations 



tion, the products being metallic silver and sulphate of peroxide of 

 iron. 



The number of veins intersecting the fahlbands at Kongsberg 

 is very great indeed. While the mines belonged to the Danish 

 government, almost the whole of them received some share of 

 attention, an extensive but rather desultory system of mining 

 thus resulting. Since the Norwegian government undertook the 

 working of the mines in 1812, a different system has been 

 pursued, rather the other extreme, of working at too few points. 

 Only three veins, those of Kongen's Gruhe, Armen Gruhe, and 

 Gottes-Hillfe-in-der-Noth, have been the subject of raining ex- 

 plorations. However this may be, the mining of the last twenty 

 to thirty years has been eminently successful, and a source of 

 considerable revenue to the Norwegian government. On account 

 of the shortness of the veins, their exploration is pursued 

 chiefly downwards, but as yet, in going downwards, no dimi- 

 nution in richness has been observed. On the contrary, large 

 masses of metallic silver, similar to those which obtained for, 

 the mines their celebrity in earlier times, have been recently 

 found. These large masses are of course the exception, the 

 most of the silver which is produced being separated from 

 the vein-stone, in breaking it up, after its extraction from the 

 mines. A large portion is also obtained in the stamping and 

 washing of middle and poor ores at the mines, and in the same 

 operations considerable quantities of more or less argentiferous 

 schlichs and shmes are produced. The whole of these products 

 are farther treated in the smelting-house in Kongsberg. The 

 poorer slimes and schlichs, containing from f to 1^ oz. per cwt., 

 are smelted with about one-and-a-half times their own weight of 

 a basic slag, containing very much ferrous oxide, from a subsequent 

 smelting, and about half their own weight of iron pyrites. The re- 

 sulting products are a regulusof sulphuret of iron, containing 3j 

 or 4* oz. of silver per cwt., and slags, containing -^-^ oz. silver, which 

 are set aside as useless. The raw regulus is roasted' in heaps, and 

 then smelted with one-and-a-half times its weight of rich slags 

 from subsequent operations, containing from 8 to 9 oz. of silver. 

 The regulus from this operation, as it is drawn off from the fur- 

 nace into the crucible outside, is there stirred up with molten 

 lead, poor in silver. From this results argentiferous lead (which is 

 used over again in the same way, until it contains from 8j to 10 

 per cent silver,) and a lead regulus (sulphurets of iron, lead and 



