124 MEMOIR ON THE 



{g) Some diftill^d water being digefled on ten grains 

 of black flaky fubiiance (No. i.) for twelve days, after 

 which it was gently heated and committed to the filter. 

 I. This liquor immediately changed the vegetable blue 

 to a red colour. 2. Lime-water caufed no precipitation. 

 3. Muriated barytes effedted no change; but, on the 

 addition of nitrated filver, a white-coloured precipitate 

 was produced. Some of the above fluid being cau- 

 tioufly evaporated to a certain quantity, on cooling, cry- 

 Itals of a cubic figure were formed. Thefe had the 

 properties of muriate of foda, or common fait. 



[b) Some marine acid, a little diluted, was poured on 

 ten grains of the black flaky fubftance, (No. i.) a 

 flight coagulation was produced, after Handing twelve 

 days. The mixture was filtered, and divided into four 

 portions. 



The firfl portion was faturated with lixivium of mild 

 pot-afh, but no precipitation enfued ; yet, in a few 

 hours, a faline fubftance appeared at the bottom of the 

 vefTel . 



To the fecond portion was added fulphurie acid. This 

 threw down a copious flocculated precipitate, of a white 

 colour, which 1 fuppofed to be lime; but, on pour- 

 ing off the fluid, a thin layer, of a white, fatty fub- 

 flance, was fpread over the bottom of the veflel. This 

 had an unduous feel, and ftained paper like oil ; and 

 emitted an animal odour when thrown upon coals. 

 This matter, when kept in a phial, corked for tvv'o 

 weeks, alfumed a yellow-colour, and had an odour liks 

 rancid fpermaceti. 



To the third portion, pruffiate of pot-afli was added, 

 and Pruflian blue produced. 



To the fourth portion, alcohol of galls was added, and 

 the mixture faturated with hxivium of mild pot-afh, which 

 immediately ftruck a black colour. 



I. 



