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IX. Obprvations on Bituminous Subftances, with a Defcription of the 
Varieties of the Elaftic Bitumen. By Charles Hatchett, if F.R.S. 
Lond. and Edinb. F. L. S. Gee 
Read May 2, une 6, and Fuly Ge 1797. 
jee. 25 
T is now generally belived that the bituminous fub{tances are 
not of mineral origin, but that they have been formed from 
certain principles of fubftances belonging to the organized king- 
doms of Nature, which, after thé lofs of animal and vegetable life, 
have fuffered confiderable cee by long contact and union with 
mineral bodies. 
Thefe changes have been feds dy fo confiderable, that the 
bitumens can no longer be referred to their firft origin, and they are 
therefore regarded by general confent as forming part of the prefent 
mineral fyftem,. 
‘The bituminous fubftances are t 
Naptha,. | 
Petroleum, 
Mineral Tar, 
‘Mineral Pitch: sotior 0) gist yoo brood (af 
. Afphaltum, 3aon of) bas 1 tom 3 
Vor. IV, S ! » Jet, 
