Chap. 41.] Newcaftk Coal, &?r. 265 



to this fubftance, and may perhaps be confidered as of 

 the fame fpecies. The moft remarkable varieties of 

 pit coal are, 



1. NEWCASTLE coal, which is of a black colour and 

 fhining appearance, where it h?s been lately broken. 

 This fubftance undergoes an imperfect fufion when 

 heated, fo as to cohere or cake. It burns with a lively 

 flame, and is nearly confumed in the fire. It does not 

 break equally in all directions, and is compofed of la- 

 minae. 



2. CULM coal. This contains a large proportion 

 of argillaceous earth, fo that after being burned its bulk 

 is fcarcely diminimed. It burns with a lively flame, 

 but its appearance is more dull and earthy than that of 

 the former. This kind of coal is found in Sweden, 

 and in feme parts of England. 



3. SLATE coal. This has very much the appearance 

 of fome of the common kinds of (late, but it burns 

 very eafily, with a copious and bright flame. It 

 confifts chiefly of argillaceous earth, and feems to 

 have only been penetrated with bituminous or coaly 

 matter. 



4. CANNEL coal is of a dull black colour, breaks 

 eafily in any direction, and in its fracture prefents a 

 fmooth chonchoidal fur face, if broken tranfverfely. It 

 is nearly confumed in the fire, burns with a lively 

 Hame, but if fuddenly heated flies in pieces with 

 confiderable violence. This inconvenience is faid to 

 be removed by previoufly immerfing it in water for 

 fome hours *. Cannel coal docs not foil the fingers, 



* It is cuftomary in Lancaftnre to fprinkle fait upon cannel 

 coal, to prevent its flying ; but I cannot fpeak decifively as to its 

 effefb, having never isen the experiment accurately made. Poflibly 

 the water contained in the fait may have fome influence in prc- 

 v entiiig the cracking of the coal. 



and 



