volatilized bituminous matters, a stratum of Jime-stpne, near Raith, 

 in Fifeshire, which, though but slightly tinged with 3, black colour, 

 contains bituminous matter like pitch, in many cavities wtich are 

 lined with calcareous spar crystallized. 



Dr. JIutton's opinions respecting the changes produced on sub' 

 terranean bitumens, by tl^e agency of fire, may be comprised in 

 tfyese two positions; first, That the purer and fluid bitumens are. 

 proceed by distillation frpm coal ; secondly, That the Kilkenny 

 coal, an4 other sijujjjar natural coke, is the residuum of this distil* 

 lation. In refutation of the first of these positions, which has been 

 also endeayoure4 tp be supported by most of the French chemists, 

 Jjttle requires to be said, except to remark, that the quantity 

 of t^e fjuid, an d purer bitumens, naphtha, petroleurn, asphaltum, 

 $;c. which ha$ been found, far exceeds the proportion of such, coal 

 as, with all that diligence of research which so useful an article has 

 excite(|, has been discovered tp have suffered this spoliation. But 

 that this substance is common coal, deprived of its bituminous 

 matter by heat, I acknowledge, seems at least to be probable. 

 When we contemplate the situations in which coal mines are placed, 

 enclosed on almost every side by strong barriers of stone, by which 

 the access of atmospheric air is almost entirely prohibited, we can- 

 not but conclude, that, should a seam of coal become ignited, the 

 coal must be completely charred, as far as its combustion extends. 

 That it furnishes any evidence in favour of all coal having beei* 

 exposed to the fusing power of heat, I acknowledge I do not per- 

 ceive ; but merely that such particular masses of coal have been 

 subjected to fires. It also shows, that such is the wise provision, 

 made, in this case, that, although a substance, formed to supply 

 mankind with fuel, should casually be subjected to the premature inr 

 fluence of fire, it shall still continue fitted for the purpose for which 

 it was originally intended : the very material changes, which it has 

 undergone, having even rendered it more highly useful, for certain 



