from the Pyrites* 323 



(8.) DiftiUed in an open fire, it yields an acid 

 fpirit, and leaves behind a bright, brown-red 

 earth, 



(9.) This earth (till proves moift in the air, yet 

 more or lefs, according as it is more or lefs burnt. 



(10.) Even after ignition in a crucible, it ftill 

 attracts, though in a very fmall proportion, the 

 moifture of the air. 



(11.) The laft feparated aluminous matter, n? 3." 

 diftilled apart, gives alfo an acid water, and leaves 

 behind a fpongy, grey, and here and there reddifh 

 fpotted cake, which equally turns moift and fmeary 

 in the air, as n° 7. 



(12.) What remains behind of n° 3. proves nelV 

 ther thicker, nor more oleaginous than before. 



(13.) What remains from the vitriol y prepared 

 from iron and oil of vitriol^ and dried, turns alfo 

 fmeary, flows in the air, and ferments with alcali, 

 but by no means with acid. 



Now, from thefe proofs thus much at leaft ap- 

 pears-, that this oleaginous refidue, from vitriol % 

 does, after exficcation and ignition, become fmeary, 

 nay, fometimes flows in the air ; but whether it will 

 ferment with acids, and thus exhibit an alcaline na- 

 ture, is a different queftion ; not that I would en- 

 tertain any doubt about M. Geoffroy's experiment, 

 as being made and repeated exprefsly, and not a 

 thing purely incidental, though it is what I could 

 never obferve: but that it may be exceedingly pof- 

 fible, appears, as was above faid, from its fponta- 



Y 2 neous 



