PEAT. 357 



If the contrast between peat and coal is far greater, 

 the resemblances are too striking to leave a doubt of 

 the origin of the latter from beds of that substance. I 

 have shown that all the geological circumstances are 

 similar or identical, in both ; the alluvial beds of the 

 one corresponding to the rocky strata of the other, as 

 do the deposits of organic substances; while the insu- 

 lated condition of each class is also a striking point of 

 resemblance. The mechanical structures of peat and 

 of coal often also present sufficient analogies: the re- 

 semblance of forest peat and the latter being often ab- 

 solute in all but the mineral character; as, in both, do 

 similar organic remains occur, and in a similar manner, 

 while, in both also, they are sometimes wanting. The 

 chemical fflcts already discussed, trace the last stage 

 from the first, through the intermediate lignites, as, 

 through this, coal has probably passed ; so that it only 

 remains to account for that dense mechanical form and 

 texture, of a schistose character, by which this substance 

 differs, not merely from forest peat, but from jet, the 

 most perfect lignite, as the nearest in its chemical na- 

 ture to coal, or, if thought necessary, by which the mpst 

 fusible coal differs from asphaltum. 



I have just explained why, in this last substance, the 

 charcoal is in a state of minute division, while that of 

 any coal must be continuous, as having been derived 

 directly from an organic structure. In the other case, 

 if jet, or lignite, retains the organic form, while coal 

 has acquired a mineral schistose texture, it remains to 

 enquire what that cause may have been. If jet be 

 fused in close vessels, its mineral character becomes un- 

 distinguishable from that of coal, as its chemical one 

 but slightly differs. Had the theory which produced 

 coal from the action of heat on wood, known this, it 

 would have at least appeared better founded : but it 



