17. 



THE COAL IN THE FIEE. 



MY dear town-dwelling readers, let me tell you now 

 something of a geological product well known, happily, 

 to all dwellers in towns, and of late years, thanks to 

 railroad extension, to most dwellers in country 

 districts : I mean coal. 



Coal, as of course you know, is commonly said to 

 be composed of vegetable matter, of the leaves and 

 stems of ancient plants and trees a startling state- 

 ment, and one which I do not wish you to take 

 entirely on trust. I shall therefore spend a few pages 

 in showing you how this fact for fact it is was dis- 

 covered. It is a very good example of reasoning from 

 the known to the unknown. You will have a right to 

 say at first starting, " Coal is utterly different in look 

 from leaves and stems. The only property which they 

 seem to have in common is that they can both burn." 

 True. But difference of mere look may be only owing 

 to a transformation, or series of transformations. 

 There are plenty in nature quite as great, and greater. 

 What can be more different in look, for instance, than 



