102 



very little bubbling ; flaking and falling to pieces in a slaty- 

 form, leaving a whitish ash. 



Mr. Kirwan describes Scotch coal from Irwine as <( hav- 

 ing layers in contrary directions, and being hence often 

 called Ribband Coal. Lustre of the alternate layers 3, 2, 

 (silky and brighter.) Fracture small grained, and coarse 

 grained, curved, foliated. Hardness 4 to 5. Spec. Grav. 

 1*259. Its composition I have not examined." 



Mr. Kirwan's description is very good, but, for the most 

 part, will agree with any stratified coal, viz. the New- 

 castle, Chesterfield, Staffordshire, &c. But this we need 

 not wonder at, from his not having examined the compo- 

 nent parts. 



I have a coal from Boroughstoneness, given me by Dr. 

 P. Murray, of the kind above described, and some said to 

 be passing into splint, varieties of which are found at New- 

 castle, Wiggan, and other places. These are often con- 

 founded with the Box Coal or Cannel Coal of Kirwan, 

 v. 2. p. 52, the true sort, which is now very scarce. Of 

 these we shall give a fuller account hereafter. 



We were favoured by Mr. E. D. Clarke of Jesus College, 

 Cambridge, in February 1804, with specimens of Lynn 

 Coal, presenting pentaedral prisms, which he has observed 

 in it for more than a year past. Other coals present this 

 figure, and also trihedral prisms. These are produced by 

 a fracture parallel to one of the diagonals of the base of the 

 •tetraedral prism. 



