204 
Another circumstance, on which Dr. Anderson dwells, demands 
a little consideration. This moss plant, he conceives, may live to an 
indefinite age, and increase to an immense magnitude, enveloping, 
in its progress, trees and every other matter which comes in its way; 
which it either consumes or preserves, according as the peculiar 
nature of each are liable to be affected by its juices. But the effects 
here mentioned are very different fi*om what the appearances in 
peat manifest The trees and other vegetable matter, which, for 
argument sake, we will for a moment consider as being thus enve- 
loped, are neither consumed, nor preserved, in the sense in which 
these words are here employed, but actually changed into a sub- 
stance of a different nature from that in which it originally existed, 
and exactly agreeing with that of the surrounding matter. That any 
living vegetable should possess chemical and physical properties es- 
sentially different from all vegetable matter, which is the case with 
peat, and should possess the power of so assimilating to its nature 
all vegetables it invested, as to form with them a homogeneous mass, 
cannot therefore, I conclude, be admitted. 
Bovey coal, that species of bituminous wood, so particularly men- 
tioned in a former letter as abounding so plentifully at Bovey in 
Devonshire, and at Munden in Germany, I must here observe to 
you, appears to be wood more highly bituminized than fossil wood 
is in general ; and may be considered as next in progression to com- 
plete bituminization. The fibrous structure, so evident in most of 
its specimens, plainly evinces its ligneous origin ; and the undulated 
and confused direction of its fibres (seen in Plate I. Fig. 2,) shews 
that, by some process, they have been so much softened, as to have 
easily admitted a distortion from their natural direction ; whilst its 
chemical properties sufficiently testify its bituminous nature. It 
appears to have been formed from vast deposits of wood, which 
have been so circumstanced, as to have undergone the bituminous 
fermentation to a certain degree ; but have not suffered a change 
