194 NOTICE OF A COAL VEIN IN 



the vein ; and when otherwise are accidental, or are produced by an 

 after cause. This fact, together with the baccilo-fibrous structure, 

 observed where the coal is in contact with the walls, are among the 

 reasons which lead us to lean towards the supposition that the fissure 

 was charged or filled at once, and that these characteristics are the 

 result of the carbonaceous matter having passed to a more solid state 

 in its present position. 



It would be rash to pronounce an opinion on the presumed extent 

 of this deposite, as well as on the probable magnitude of the vein be- 

 low the point at which it is visible, or the depth to which we have 

 had access; but if the vein continues to enlarge downwards, in the 

 same proportion as it has augmented in the first thirty feet, or even if 

 it holds the present breadth of nine feet, the quantity of this mineral 

 must be very great, and will prove a highly acceptable discovery, so 

 near a great city, and in a district from which nearly all the timber 

 for fuel has been long ago removed. 



Quality of the Coal. 



This coal is unusually light : its specific gravity being not more than 

 1'142; and two other experiments on heavier specimens gave 1'18, 1*1 9. 



It is perfectly jet black; having a resplendent lustre, which is much 

 greater in one sense, or under one aspect, than in the other, and it 

 divides in parallel layers in the mass. The surface of the divisions, or 

 partings, in the coal, is brilliantly shining. Its cross fracture is rough, 

 and has a glimmering, pitchy appearance. 



We have now to advert to an external character, which is very com- 

 mon, and in fact is of constant and universal occurrence in this coal; 

 a feature which distinguishes it from all other coals which have come 

 to our knowledge, in any quarter of the globe. Its horizontal fracture 

 or surface is marked by numerous concentric, or rather eccentric, rings 

 of various sizes, from a twentieth part of an inch to a foot in diameter. 

 They are perfectly regular and uniform in shape, smooth, shining ; 

 resembling the impressions made hy a seal in black wax; or, when 

 first seen, appear like the casts of the flat valves of some shells. 



This coal is exceedingly friable, breaking into small fragments under 

 the hammer. Its powder is brown, and when pressed under the pestle, 



