146 MR HAIDINGER oil the Natural-Historical 



rieties that shew a higher specific gravity, namely, the Serpen- 

 tine from Matrey in the Tyrol, G. 2.700, from the Hartz, 

 G. = 2.684, from Lower Stiria, G. = 2.667. The difference 

 of the latter can easily be explained by an admixture of Iron- 

 ore, for 8 per cent, of this mineral mixed with 92 per cent, of a 

 Serpentine, whose specific gravity is 2.5, will suffice for raising 

 that of the compound to 2.72 ; but the same explanation cannot 

 apply to the Serpentine from Monteferrato, and a difference of 

 that kind, not yet accounted for, must, of itself, be sufficient for 

 directing the attention of mineralogists towards a more accurate 

 examination in future, of the different varieties of Serpentine. 



Thus, mineralogy being the natural history of the mineral 

 kingdom, must correctly determine the different varieties, and 

 collect them within well defined species ; but in this, it has ful- 

 filled its duty, at least as far as respects the establishment of the 

 species, and it must leave a great deal of valuable information to 

 be obtained from other sciences, which likewise refer to the mi- 

 neral productions, as, for instance, from natural philosophy, geo- 

 logy, chemistry, the art of working and smelting ores, &c. The 

 first determination of a mineral, if incorrect, is very often preju- 

 dicial to all the subsequent inquiries, and it would not be diffi- 

 cult, from more than one example, to support this observation. 

 An accurate investigation of the rocks, can alone enable the geo- 

 logist to ascertain the nature of the materials of which mountains 

 are composed, the grand object of his researches ; and hence the 

 fundamental knowledge of the mineral species which natural his- 

 tory affords, is as necessary to him, as it is to the chemist, who 

 intends to subject them to his analysis. 



G. ROSE has given us a beautiful example of the latter, in 

 his memoir on the different substances hitherto indiscriminately 

 comprised under the name of Felspar *. The difference among 



* GILBEET, Annalen der Physik, &c. 1823. 



