820 



COAL 



change by which bituminous coal has been produced from vegetable fibre, and that 

 we have not completed all the links in the chain between brown coal and true coal. 



The following Table shows at a glance the chemical difference between wood and 

 brown coal on the one hand, and anthracite on the other ; and servos to explain what 

 has been said of the chemical changes by which wood is supposed to pass into bitu- 

 minous and, eventually anthracite coal: 



Brooke and Miller divide coal into three varieties: 1. Anthracite; 

 coal ; 3. Brown coal. The chemical differences between those being : 



2. Black 



Carbon 



Hydrogen 



Oxygen 



Nitrogen 



Ash 



l 



94-10 

 2-39 

 l-34\ 

 0-87J 

 1-30 



2 



83-75 

 5-66 



8-04 

 2-55 



3 



73-79 

 7-46 



1370 

 4-96 



Other mineralogists, as Dana, divide coal into bituminous and non-bituminous ; and 

 under these divisions they group the numerous varieties of coal which occur, as 



BITUMINOUS VARIETIES. 1. Pitch or caking coal (Dana), which burns readily with 

 a yellow flame, and which on receiving the heat, unites into a solid mass ; thus 

 requiring poking to prevent a too complete consolidation of the mass. 2. Cherry 

 coal somewhat resembles caking coal, but in burning it does not soften or cake. It 

 burns more rapidly than caking coal, with a clear yellow flame. 3. Splint coal or splent 

 coal is in Scotland a term for a hard laminated variety of bituminous coal, intermediate 

 in texture, between caking and cannel coal. The name is derived from its splitting 

 (or splenting) up in large flaggy or board-like laminae (Page). It is a coarse kind of 

 cannel coal (Dana), A variety of bituminous (cannel) coal, with a slaty structure, 

 and of a harder and tougher nature than cherry coal. Splint coal is used by Lyell 

 as the equivalent to anthracite. 4. Cannel coal. A. coal with a fine compact 

 texture, a large conchoidal fracture ; it receives a good polish ; is sonorous when 

 struck. It is coal more perfectly bituminised than No. 1. In Scotland this coal is 

 called parrot coal from the crackling, chattering noise which it makes when first 

 thrown into the fire. 



Jet resembles cannel coal, but is blacker, and has a much more brilliant lustre. 



Flint Coal. A kind of coal resembling anthracite in appearance ; but containing 

 bitumen. 



Flew Coal. A coal resembling flint coal. It must be regarded as a local name for 

 the coal found at Wedgebury in Staffordshire. 



Crow Coal. A coal found near Alston, containing but a small quantity of bitumen. 



Albert Coal or Albertite. A bituminous coal found in Nova Scotia; it lias the ap- 

 pearance of asphaltum, and is partially soluble (about 20 percent.), but it has not the 

 fusibility of asphaltum. 



