MODE VI. SERPENTINE. 



daries, and the nephrite of the Germans ; only 

 different from other compact felspar by its tena- 

 city, weight, and unctuous appearance, while it 

 melts under the blow-pipe like other felspars. 

 The able and ingenious Haiiy has added the 

 lemanite, or white jad, as an appendix to fel- 

 spar, under the name offelspath tcnace ; while 

 he ranks jad, the nephrite of Werner, among the 

 substances whose characters are not sufficiently 

 known to find a place in the system. He re- 

 gards the axe-stone as totally different from the 

 oriental jad, of which he gives two analyses, one 

 by the younger Saussure, who found iron, man- 

 ganese, soda, pot- ash, &c. &c. and has acquired 

 little reputation as a chemist. Karsten, in his 

 tables of mineralogy, Berlin 1808, has given 

 another, by Kastner, which is probably authen- 

 tic, and deserves repetition ; silex 50, magnesia 

 31, argil 10, water 3, oxyd of iron 5, with a tint 

 of chrome. 



Mineralogists having in general supposed that 

 jad or nephrite occurs in veins or layers in ser- 

 pentine rocks, it was proper some account should 

 be given of so remarkable a substance. For the 

 same reason, it may be proper here to mention 

 asbestos and amianthus, almost constant in the Asbestos. 

 midst of serpentine, but which cannot be regarded 

 as forming rocks. The 1 ate ingenious Dr. Walker, 



