Elements of Mineralogy. 

 mouth/hire in fmall pieces, Phil. Tranf. 

 p. 20, alfo in th Vharais, Genfanne hiji. 

 guedoc, vol. 3. p. 208. Henckel alfo men- 

 tions it in his Flora Saturnifans. If it con- 

 tains copper, this latter may be detected by 

 a plate of iron immerfed in its folutio'n in 

 nitrous acid, and the prefence of filver, if 

 any be contained in it, will be difcotfered by a 

 plate of copper. 



SPECIES II. 



Mineralized by the Aerial Acidi 

 Calciform 



3. Of thefe we may diftinguim 5 varieties,' 

 all eafily foluble in nitrous acid, and with 

 efFervefcence if heat be ufed, and alfo in 

 exprefled oils ; all contain a little iron, but 

 Jiever filver. 



I. VARIETY* 

 White, Lead Spar, Lead Ochre, Native Cerufs. 



4. Lead Spar is fometimes tranfparent, but 

 generally opake, and cryftalifed in regular 

 forms, of a laminar or ftriated texture. Lead 

 ochre, or native cerufs is the fame fubftance, 

 but in a loofe form., or indurated and fhape- 

 lefs j fometimes it is found in a filky form. 

 Both contain a little iron, and fometimes 



calcareous 



