160 ON THE FORMATION OF COAL v 



had invested in the ancient club-mosses. The 

 eighteenth century arrived, and with it James 

 Watt. The brain of that man was the spore out of 

 which was developed the modern steam-engine, and 

 all the prodigious trees and branches of modern in- 

 dustry which have grown out of this. But coal is 

 as much an essential condition of this growth and 

 development as carbonic acid is for that of a club- 

 moss. Wanting coal, we could not have smelted 

 the iron needed to make our engines, nor have 

 worked our engines when we had got them. But 

 take away the engines, and the great towns of 

 Yorkshire and Lancashire vanish like a dream. 

 Manufactures give place to agriculture and 

 pasture, and not ten men can live where now ten 

 thousand are amply supported. 



Thus, all this abundant wealth of money and of 

 vivid life is Nature's interest upon her investment 

 in club-mosses, and the like, so long ago. But 

 what becomes of the coal which is burnt in yield- 

 ing this interest ? Heat comes out of it, light 

 comes out of it ; and if we could gather together 

 all that goes up the chimney, and all that remains 

 in the grate of a thoroughly-burnt coal-fire, we 

 should find ourselves in possession of a quantity 

 of carbonic acid, water, ammonia, and mineral 

 matters, exactly equal in weight to the coal. But 

 these are the very matters with which Nature 

 supplied the club-mosses which made the coaL 



