*44 ^- ^ A T c H ET T*f Obfirvaiktis on Bituminous- Sub/lances: 



The characters of bitumen are much more apparent in turf and' 

 psat, than in the greater part of the fofTil woods. Turf is well known 

 to bo, compolid of the parts of vegetables, fuch as fmaiL roots, 

 twig?, &e„ mixed with a portion of petroleum ; and peat is the 

 fame, excepting that it generally contains more of earthy matter, or 

 that the vegetables have undergone a more complete decom- 

 pofition. 



The boggy nature of the places in which they are found, proves 

 that a certain degree of maceration is neceffary to form the bitu- 

 minous matter which they contain; and I have already noticed, 

 that every fact appears to demonstrate, that the bitumen is a pro- 

 duel: of thofe vegetables, the remains of which conftitute the other 

 ingredient of turf and peat. 



The different proportion of vegetable matter, of bitumen, and of 

 earth, together with the different ftate of the bitumen, as well as 

 the degree of perfection refpecting the formation of it from the 

 vegetable principles, contribute to alter the properties and characters 

 of the compound, and thus produce varieties. It is believed that 

 thefe fubftances have been materially concerned in the formation of 

 pit-coal, and fome eminent mineralogifts maintain that there is an 

 uninterrupted feries which connects the varieties of turf and peat 

 with thofe of coal**. 



rented, but affo of all putrid vegetable and animal bodies : hence it is found in vegetable 

 and animal manures that have undergone putrefaction, and is the true bafis of their ame- 

 liorating powers ; if the water that panes through a putrefying dunghill be examined, it 

 will be found of a brown colour, and if fubjetted to evaporation, the principal part of the 

 refiduum will be found to confift of coal. All foils fteeped in water communicate the 

 fame colour to it in proportion to their fertility ; and this water being evaporated, leaves 

 alfo a coal, as Me firs. HaiTenfraz and Fourcroy atteft." — Kirivaa on Manures > p. 154, 

 Vol. v. of The TranfaBions of the Royal Irijb Academy. 



* Man findet in der natur einen ununterbrochenon libergang von dem rafen und 



papier tor f 



