245 



and of earthy matters, from submarine volcanoes. How, he says, 

 can it be supposed, that coal can have been formed from vege- 

 tables, when considerable beds exist at the height of twelve thou- 

 sand feet in the Cordilieres of Peru, and at more than six thousand 

 feet in height on the Dauphinese Alps ; where, he adds, these beds 

 have been deposited, at a time when vegetables did not yet exist, 

 and when the waters covered the whole surface of the globe. How 

 otherwise, he asks, can we account for the regular alternate beds 

 of coal and layers of stone ; such as, for example, are seen in the 

 colliery at Liege, where there are sixty-one beds of coal, alternating 

 with as many layers of stone, of a vast thickness*. 



The latest writer of celebrity on this subject is Mons. Fourcroy, 

 who, speaking of the origin of this substance, says, the greater part 

 of naturalists consider coal as the product of the remains of wood, 

 which has been sunk, and afterwards changed by the water, and by 

 the salts of the sea. Coal, he observes, seems to owe its formation 

 to the decomposition of an immense quantity of marine and terres- 

 trial vegetables, and to the separation of their oil, which becomes 

 united to the aluminous and calcareous earth. It cannot be denied, 

 he remarks, that animal matters also enter into its composition, 

 and afterwards observes that a considerable quantity of ammonia 

 is yielded by the distillation of coal, which favours the opinion of 

 its animal origin, since bodies belonging to this class of compound 

 substances always yield ammonia during their distillation-)-. 



Evident indecision is observable in the foregoing opinion, re- 

 specting the formation of coal ; doubtlessly arising from Mons. 

 Fourcroy 's disposition to countenance the idea of animal bodies 

 having contributed greatly, and perhaps even more than vegetables, 



* See article HOUILLR, Dictionnaire d'Histoiric Naturelle. 



t Systenie des Connoissances Chymiques, torn. viii. p. 241 et 244. 



