134 Dr. Berger on the physical Structure 



It we now compare the analyses of these different rocks In order 

 to ascertain, if in their chemical composition, there is the same 

 analogy which their geological situations seem to indicate, the result 

 of that examination will prove by no means so conclusive. 



Although serpentine is in itself a simple rock, we find it so often 

 mixed with foreign substances, that it is impossible to obtain by che- 

 mical analysis any uniform results. Thus Kirwan has found in one 

 experiment, 0,18 of alumina, while Klaproth found none. Kii^wan 

 gives 0,23 as the proportion of magnesia, Bayen 0,33 : but there are 

 €ven greater diiferences in these analyses.* 



With regard to the analyses we have of diallage, by Vauquelin, 

 Drappier, Heyer and Gmelin, they all state a greater or less propor- 

 tion of lime, a substance never found in serpentine. The smaragdite 

 contains besides, according to Vauquelin, as much as 0,08 of oxide 

 of chromium, and a little oxide of copper. There are also great 

 differences in the proportions of the same principles in the green and 

 metalloidal varieties. Vauquelin found in the first, 0,06 of mag- 

 nesia, 0,21 of alumina; and Drappier found in the second, 0,29 of 

 magnesia, and only, 0,03 of alumina. f Lime is also, according to 

 Hoepfner and Theodore de Saussure, one of the component parts of 

 jade, but the first finds in it as much as 0,38 of magnesia, while 

 Saussure makes no mention of it. On the other hand, Saussure 

 found soda and potash in jade, but Hcepfner does not seem even to 

 have suspected their existence. :J; 



" ve7'(le dci Corsica duro of the Italians. Brochant, Traite dc Mineralogic, tome i. 

 " p. 423." 



* Brochant, Traite dc Mineralogic, tome i. p. 483. 



+ Broiigniart, Traite Elementairc de Mineralogic, tome i. p. 442. 



Brochant, Traite de Mineralogic, tome i. p. 42\?. 

 J Idem, tome i. p. 468. 



Journal de Phyisque, Mars, 1807, Analyse dc la Saussurite appclee lehmanite par D.' 

 la Methcric. 



