GEOLOGICAL SOCIETY OF PENNSYLVANIA. 



273 



Ashes free from carbonate of lime, very little iron, 

 colour grey. 



Mineral Charcoal. Marked JVo. 14. 



This specimen of mineral charcoal, presented to the 

 Geol. Soc, by Mr Miller, is a fibrous, pulverulent, 

 black, combustible substance, found disseminated in the 

 beds of bituminous coal of the coal field through which 

 the Portage Railroad has its course ; and I understand is 

 not uncommon in other coal fields of this state. In 

 Europe it is found at Potschapel near Dresden, and at 

 Waldembourg in Silesia. It has sometimes been termed 

 anthracite from its burning with difiiculty ; this appella- 

 tion is erroneous. Mr Karsten remarks, concerning this 

 matter, that when a coke contains much of it, that it 

 forms itself into masses which choke the furnace, and 

 refuses to burn. This is explained by the fact of this 

 substance falling with ease into a powder ; and the powder 

 of charcoal, as well as this, resists the action of the 

 strongest blowing machines. The powder of mineral 

 charcoal being rather more dense than that of wood, is 

 less easily penetrated by the wind. The difiiculty of 

 burning is always more or less apparent in those bodies 

 that are traversed with difiiculty by the air.^^ 



The specimen which we examined, easily reduced to 

 powder, which is a dead black. When calcined in close 

 vessels, it does not materially change its aspect; by 

 distillation gives bitumen, water and alkaline gas. It is 

 free from pyrites, and apparently pure; the cinders were 

 yellowish red, free from lime. 



Composition per cent. 



Carbon, 0.664 



Cinders, 0.270 



Volatile matter, . , . , . . 0.066 



1.000 



I.— 2 K 



