185 me. hatchett's observations 



tion ; the infallibility of this depolit when again digefted with 

 water, alcohol, or ether; the fmoke and odour which it yielded 

 when burned; and the precipitates formed by the addition of 

 fulphate of iron and muriate of tin to its folution; when thefe 

 properties, I fay, are confidered, there feems much reafon to 

 conclude, that the fubftance difiblved by water was vegetable 

 extract, which had apparently fuffered fome degree of modifi- 

 cation, but not fufficient to annul the more prominent charac* 

 teriftic properties of that fubftance. 



The powder of the fchifhis, which had been employed in 

 the preceding experiment, was afterwards digefted in alcohol 

 during two days ; and a pale yellow tincture was thus formed, 

 which, by evaporation, left about one grain of a yellow tranf- 

 parent fubftance, pofTefTing the properties of refin. 



jt contained It appears, therefore, that a fubftance very analogous (6 



liaft* anA C *Yitt\t ve & eia ^- e extract, and a fmail portion of refin, remain inherent 



refin, in the leaves of this remarkable fchiftus. 



but no tannin. As folution of ifmglafs did not produce any effect, there was 

 reafon to conclude, that the aqueous folution above-mentioned 

 did not contain any tannin ; but, as the tannin might be com- 

 bined with the alumina of the fchiftus, I digefted a portion of it 

 in muriatic acid, which, after filtration, was evaporated almoft 

 to drynefs, leaving, however, the acid in a flight excefs. This 

 was diluted with water; and afforded a blue precipitate with 

 pruffiate of potafh, a yellowifh precipitate with ammonia, and 

 a white precipitate with muriate of tin, but not any with fo- 

 lution of ifmglafs. The tannin which might have been con- 

 tained in the recent vegetable, appears therefore to have been 

 diffipated or decompofed, with the greater part of the other 

 vegetable principles, excepting the woody fibre reduced to 

 the ftate of an imperfect coal, and the fmall portions of extract 

 and refin which have been mentioned. 



Previous to having made the analyfis, I had an idea, that this 

 fchiftus might be a lamellated incruftation, formed by the tufa 

 of the hot fprings; but, according to Mr. Klaproth's analyfis *» 

 the tufa of Geyfer is compofed of, 



Silica 98 



Alumina - 1.50 



Iron - 50 



100. 

 * Beit r age ; Zweiter band, p. 109. 



