MODE IR ANTHRACITE. 559 



Isere, near Allemont, towards the summit of the 

 mountain of Challanches, at an elevation of 2563 

 yards, is secondary. It lies between two beds 

 of black schistus, covered with impressions of 

 vegetables; it contains no bituminous matter, 

 and has 0,97 of carbon, so that it is nearly pure 

 carbon. That of Rousses, opposite the same 

 mountain, and that of Venose, near the village 

 of Oysans in the same valley, are also of se- 

 condary formation. The anthracite of Lisch- 

 witz, near Gera in Saxony, is in layers of 

 clay-slate, covered with vegetable impressions. 

 (Roemer.) 



" The anthracite which contains no indication 

 of vegetable coal, is wholly incombustible ; that 

 which contains any, may burn, if two- thirds of 

 charcoal be added to it. (Hericart-Thury.)"* 



Brochant observes, that if anthracite be held 

 a long time on fire, moving it often, it consumes 

 slowly without any flame; but only encircled 

 with a little glory, or irradiation, like red iron 

 and diamond. During this operation it loses 

 about two-thirds of its weight, and the residue is 

 of a blackish grey, which announces that the 

 combustion is imperfect. 



* Brongn. U. 5$. 



