85 



resolution of animal and even vegetable matter, in subterranean 

 situations, may also have proceeded the various metallic and other 

 phosphates, so eminent in their brilliance an4 colours. 



Yours, &c. 



LETTER X. 



PEAT OR TURF.. ..DESCRIPTION OF.... VARIOUS KINDS. ...LENGTH OF 

 TIME KNOWN.. ..FOUND IN VARIOUS PARTS OF THE WORLD. 



THE substance, to which I next wish particularly to attract your 

 attention, is one which has been seldom considered in relation to 

 the bodies termed petrifactions ; but which I suspect, is very nearly 

 connected with those which derive their origin from the vegetable 

 kingdom. Indeed, I shall endeavour to prove to you, that most 

 of these bodies which have obtained so considerable an alienation 

 from their original nature, have first passed through an intermediate 

 state ; resembling that, in which the substance which is the subject 

 of our immediate inquiry, is always found to exist. 



The substance here alluded to, is peat or turf; well known to the 

 inhabitants of most lowland countries, for the advantages it affords 

 them by its combustible quality. It is found in various parts of the 

 world, forming immense tracks, at various depths. It is a soft but 

 compact substance ; its colour being of a bright reddish brown. As it 

 dries, upon exposure to the air, it becomes soon darker ; the dark- 



