104 



There is little doubt of the Denbigh coal being nearly as 

 pure an oxide of carbon as is likely to be found. " Its 

 colour is black ; its lustre from 3 to 4, approaching the 

 metallic. Transparency 0. Hardness 4 to 5 : brittle : stains 

 the fingers." It could only be the softer part occasionally 

 found in this coal that stains the fingers ; as in that from 

 Swansea, resembling charred wood ; dusty and with less 

 lustre than above-described *, and what he denominates 

 Culm coal of Wales ; another variety which agrees with 

 what Werner calls Glanz-Khole. 



Denbigh coal is seldom stratified, and is apt to separate 

 with a reedy structure, or impression, in irregular striae. 

 The cross fracture is often conchoidal and undulating. This 

 fracture and the prismatic hues for which this coal is famous, 

 have naturally gained it the appellation of Peacock coal ; 

 and it is no less remarkable, that a piece with the colours 

 on it, may be heated red hot many times, and, on cooling 

 again, will return to nearly the same appearance, retaining 

 its prismatic hues. 



We are happy to say Mr. Jameson promises to give a 

 fuller account of his khole-blend, at some early opportu- 

 nity, and has also promised, with his usual generositv, to 

 supply us with specimens. All coals commonly so called 

 produce a black powder. 



* This, when irregular and loose, as it sometimes is, appears by the de- 

 scription to be the smut of this author. Culm means only smallish coals of 

 inferior value, which do not pay duty. 



