CHAPTER XXI. 



COAL. 



Foaud to be of vegetable origin. Prof. Rogers on Coal. Statementi 

 faulty. Unacquainted with natural law. Rogers' theory. Grew 

 in n swamp. Soaked with mineral oils. Baked by the earth'i 

 internal fire. A. forest makes half an inch of coal. A tree said to 

 absorb carbon. Incorrect. Sir Henry De la Beche and his calcu- 

 lations. Fallacies about carbon. How carbon and hydrogen came 

 into the coal. Our theory of coal. Prairies. Charcoal in the 

 seams. Nova Scotia mines. Inundations. No internal fire. No 

 Baking. The whole process one of petrifaction. Coal inexhaus- 

 tible. 



FOR a great many years, this useful production of nature was 

 very little understood. It was classed among the ordinary 

 minerals, and was supposed to have been made in a similar 

 manner " oat of nothing by fire" Geologists, however, in pur- 

 suing their researches some thirty years ago, found numbers of 

 fossil leaves and stems among the coal ; and in the shale (a 

 stratified kind of rock always found in connection with coal) 

 appean-tl a 1' rest of fossilized vegetation. The conclusion was 

 then arrived at, that coal was of vegetable origin. 



After this h 1 1 l<'ii discovered, numberless theories were 

 thrown out regarding the way in which these coal fields were 

 produced; but wi- have, not seen one that gives an altog-tlur 

 satisfactory solution of the problem. 



