ON BITUMENS, &C. ] g£ 



light gray furface being generally of a blackifh-brown, which 

 is alfo the colour affumed by the fchiflus when reduced to 

 powder. 



The leaves appeared to be in the ftate of charcoal, by being The leaves al- 

 extremely brittle, by the blaekifh brown colour, by deflagrating ™*j" f the ftate 

 with nitre, by the manner of burning, and by forming car- 

 bonic acid. I was, however, foon convinced that the fub- 

 ftance of thefe leaves was not complete charcoal, but might 

 more properly be regarded as vegetable matter in an incipient 

 ftate of carbonization, which, although pofTeffed of many of 

 the apparent porperties of charcoal, ftill retained a fmall 

 portion of fome of the other principles of the original vege- 

 table. 



My fufpicion was excited, partly by the odour produced but burning with 

 during combuftion, which rather more refembled that of wood V vo 0( j, OUr ° 

 than that of charcoal, and partly by the brown fplution 

 formed by digefting the powder of the unburned Ichiftus in 

 boiling diftilled water; for, by various lefts I afcertained, that 

 the fub fiance thus difTolved was not of a mineral nature. In 

 order, however, fully to falisfy myfelf in this refpect, I digefted Digeftron of the 

 250 grains of the pulverized fchiflus with fix ounces of water. and ' examination 



The liquor was, as before, of a dark brown colour. of the folution. 



It had but little flavour. 



Prufliate of potafh, muriate of barytes, and folution of 

 ifinglafs, did not produce any effect; nitrate of filver formed a 

 very faint cloud; fulphate of iron was flowly precipitated, of 

 a dark brownifh colour; and muriate of tin produced a white 

 precipitate. 



A portion of the folution, by long expofure to the air, was 

 partially decompofed ; and a quantity of a brown fubftance was 

 depofited, which could not again be difTolved in water. 



Another portion was alfo evaporated to drynefs, and af- 

 forded a fimilar brown fubftance, which was only partially 

 foluble in water; and the refiduum, in both of the above 

 cafes, was found to be infoluble in alcohol, and in ether. 



When burned, it emitted fmoke, with the odour of vege- 

 table matter. 



250 grains of the fchiftus, afforded about three grains of the 

 above fubftance; and, when the properties of the aqueous 

 folution are confidered, fuch as its partial decompofition, and 

 the depofit which it yielded by expofure to air, and by evapora- 

 tion : 



