ANTHRACITE COAL. lit 



common brown coal is firmer than most of the varieties, has traces of 

 woody structure, and has a conchoidal fracture, with considerable lustre. 

 Among the black coals are the pitch coal of velvet-black, but sometimes 

 brownish, with strong lustre aud perfect conchoidal fracture. Slate 

 coal has a coarse structure, somewhat lamellar and hard; foliated 

 coal has thinner laminae, and coarse coal is similar, with smaller parti- 

 cles ; and is somewhat granular. Cannal coal has a flat conchoidal 

 fracture in every way, with little lustre ; it is harder and smoother 

 than most varieties. 



These coals, though divided and possessing different degrees of in- 

 flammability, have certain characteristics in common. Some form coke, 

 and others are soft on burning, giving off more or less smoke, with 

 different lights, and leaving different products. They are decomposed 

 in a large way to obtain their gases for burning as light in cities. The 

 coked coal is used for smelting metals. All exhibit their vegetable 

 origin, though some are not so distinctly marked as others, or the an- 

 thracite. Some are found above the chalk formations, and even in 

 the diluvial and alluvial deposits. They naturally alternate with 

 clay-slate, sand-stone, lime-stone, &c., of the secondary series, and 

 are often associated with animal exuvia, iron-pyrites, &c. They are 

 the coals of Europe, and they also abound in Va., Penn., Ohio, and 

 some other western states. 



Anthracite, or Mineral Coal, though classed as a mineral ; yet, be- 

 ing acknowledged to be of vegetable origin, it properly belongs to the 

 vegetable kingdom. Its mineralogical character is described as co- 

 lor greyish and jet black; lustre imperfectly metalic ; opaque ; speci- 

 fic gravity 1-4 to 1-6 fracture conchoidal. This is one of the best, if 

 not the very best, kinds of coal. Some of the varieties have highly 

 iridescent colors, with a columnar structure, and variable lustre. Its 

 geological position is confined to the transition rocks. It consists 

 chiefly of carbon, with a proportion of oxide of iron, silex, alumina, 

 &c. It is not so widely distributed as the bituminous coals, being 

 little known in Europe, except in small veins, not worth working ; but 

 it abounds in the U. S., and during the last twenty years has been con- 

 sumed in large quantities. It is ignited with difficulty, arid it was 

 therefore introduced into use very slowly ; but grates being adapted 

 for its combustion, it soon came into general notice and esteem, and its 

 consumption since has rapidly increased, not only for warming apart- 

 ments, but for all manufacturing purposes ; and, more recently, for 

 producing steam. It is devoid of all the smoke and smell which char- 

 acterises the bituminous coal, and its heat is much greater ; so that 

 its advantages are far superior, for most purposes. The extent of this 

 coal in Penn. is well known ; it furnishes 2-3ds of the coal consumed in 

 the U. S. It is of easy access, being in hills mostly 200 or 300 feet 

 above the water, and from 15 to 40 feet thick. The beds are mostly 



