ON BITUMENS, &C. ] g£ 



apparently reduced almoft to the ftate of charcoal, neverthe- 

 lefs retain fome part of their original proximate principles, 

 namely, extract and refin. This, of itfelf, is undoubtedly a 

 remarkable fact ;■ but, if it were unfupporled by any other, 

 the only inference would be, that the fchiftus was moll pro- 

 bably of very recent formation, and had been produced under 

 peculiar circumftances. 



I was defirous, therefore, to difcover fome fimilar cafes, "quires an at- 

 which might ferve as additional corroborative proofs of the m j ne °ai bitu- " 

 gradual alterations by which vegetable bodies become changed, mens. 

 fo as at length to be regarded as forming part of the mineral 

 kingdom ; and, from the reafons which have been ftated in 

 the commencement of this paper, as well as from a certain 

 fimilarity in the external characters of the fubftance compofing 

 the leaves above-mentioned with thofe of the Bovey coal, 

 I was induced to make this laft alfo a fubjecl ©f chemical 

 inquiry. 



In the Philosophical Tranfa6tions for the year 1760*, fome Bovey coal, 

 remarks on the Bovey coal, and an account of the flrata, are 

 ftated, in a letter from the Rev. Dr. Milles to the Earl of 

 Macclesfield. The object, indeed, of the author, was to efta- 

 blifh that this and fimilar fubftances are not of vegetable, but 

 of mineral origin ; and, to prove this, he adduces a great 

 number of cafes, moft of which, however, in the prefent ftate 

 of natural hifiory and of cbemiftry, muft be regarded as 

 proving the contrary ; whilft others, mentioned by him, fuch 

 as the Kimmeridge or Kimendge coal, are nothing more 

 than bituminous flates, and of courfe are of a very different 

 nature. 



Dr. Milles's account of the varieties of the Bovey coal, and Its hiftory. 

 of the ftate of the pits at that time, appears to be vary ac- 

 curate ; and, for the prefent ftate, or at leaft fuch as it was 

 in 1796, I (hall beg leave to refer to a paper of mine, pub* 

 lifhed in the fourth volume of theTranfactions of the Linnean 

 Society f; for, as this is more immediately a chemical invef- 

 tigation, I wifh to avoid, as much as poffible, entering into 

 any minute detail of geological circumftances. 



* Vol. LI. p. 534. 



f Obfervations on bituminous Subftances, p. 138. See alfo 

 Parkinfon's Organic Remains of a former World. Vol. I. p. 120'. 



It 



