338 FORMATION OF PRIMITIVE MOUNTAINS. 



stances which compose these minerals; but always in 

 determinate proportions, either by adding a foreign sub- 

 stance, or by regulating the fusion by the choice of mi- 

 nerals. The combinations which the metallurgist thus 

 produces, are ordinarily minerals which have already 

 been found in nature, sometimes even new species. 



During a journey in Sweden, Mitscherlich observed at 

 Fahlun, where he made inquiries regarding the ores, the 

 scoriae, and in general regarding the extraction of copper, 

 in order to form a correct idea of this operation, not on- 

 ly some well-formed crystals in the scoriae; but also 

 found that the whole mass of the slag had a crystalline 

 texture; and that the crystals, and the joints of the 

 slags which had a lamellar texture, remained the same 

 at different periods of fusion, provided only that the 

 manner of operating of the metallurgist remained the 

 same. The examination of the crystalline figure of the 

 slag proved, that it was that of a mineral which has a 

 composition analogous to that of the slag. After having 

 made this observation, he found in almost every foun- 

 dery which he visited in Sweden, different crystalline 

 combinations, which resembled minerals. Thus he found 

 at Fahlun, silicate and bisilicate of protoxide of iron; at 

 Garpenberg,mica, and several times augite and chrysolite. 

 These combinations have not only the same crystalline 

 figures, but also all the other characters of the corre- 

 sponding minerals. 



I have pursued these inquiries, says Mitscherlich, since 

 my return from Sweden ; I have analysed the produc- 

 tions which I have found, and the analysis has confirmed 

 what the exterior had led to anticipate. I have also aug- 

 mented my observations by journeys in various districts 



