208 Elements of Mineralogy. 



PART III. 



Inflammables. 



UNDER this head 1 do not comprife all 

 minerals that may be inflamed if expofed 

 to a ftrong heat, for other wife feveral fulphu- 

 reous metallic ores, pyrites, and even fome 

 metallic fubilances, diamonds and plumbago, 

 fhould be arranged under this clafs, which 

 would occafion that confufion which is meant 

 to be avoided by fyftematic claffification, but 

 merely thofe fubftances, which in facT: are in- 

 flammable, and do not come under the denomi- 

 nation of Earths, Salts, or metallic ores, and 

 have general characters perfectly diftindt 

 from them. Of thefe forne are fluid, fome 

 liquid, and fome folid ; the fpecific gravity 

 of the latter never exceeds 2,5, and the former 

 are the lighteft of all bodies. The French 

 beftow the name of Bitumen upon all liquid 

 and folid mineral inflammables, except ful- 

 phur ; the Germans by that nariie denote only 

 the folid. Thefe are all, except coal, elec- 

 trics, per fe> and infoluble in water and fpirit 

 of wine, but foluble in fome fpecies of oil. 

 Mr. Lergman fays he poflefTes a concrete 

 rape-feed oil, which is hard and pellucid like 

 copal, and infoluble in water and fpirit of 

 wine. 2 Erde. Befchr. 267. 



SPECIES I. 



