202 FORMATION OF COAL, 



Ash ... ... ... ... ... 2*50 



Fixed Carbon (a powder) 8875 



Volatile matter ... ... .. ... 8*75 



JOO'OO 



On applying heat, a little gas was given off which burnt with a 

 blue flame j when the air was excluded, a blackish brown powder 

 with little cohesion remained. The ash was snuff coloured. 



As to the origin of these layers, I confess I find it difficult 

 to account, but it is possible they represent different plants. They 

 seldom run more than a few inches in length, and are not arranged 

 in any regular order 3 it will be observed that they differ much in 

 chemical composition and form, a basis by which a coal may be 

 judged at sight, Near a fault the layers are so crushed that it 

 is difficult to distinguish them. 



It is suggested that the plants forming coal were allied to 

 those which, at the present time, grow in water and swamps, 

 namely, reeds, m.osses and ferns. The peat deposits of to-day are 

 composed of moss, and these, if left to nature, might in time form 

 coal. Such vegetation would be a mass so thick and compact, that 

 sediment contained in the submerging water would not penetrate 

 to any extent, and thus we can conceive a pure seam of coal 

 of an equal thickness being formed thereby. 



Now comes the question, how did this vegetable matter 

 become coal, and by what agency did the metamorphosis take 

 place. The conditions must have been such as to produce only 

 partial decomposition 3 had these plants decayed as vegetation does 

 strewn on the earth's surface, their elements would have combined 

 with the oxygen of the air, and gradually produced new com- 

 binations. But those which formed the coal, cannot have gone 

 through the whole process of decay 3 hence, decomposition must 

 have taken place under water. Two propositions have been 

 advanced to account for the accumulation of these plants in water. 



