BTACK SAND ON THE BANKS OF THE DON. gl 



luicc its weight of carbonate of potash, and exposed for 

 two hours to a red heat, in a porcelain crucible. The mass, 

 being softened in water, was digested in muriatic acid. By 

 repeating this process twice, the whole was dissolved in mu- 

 riatic acid, except a brownish white matter, which, being 

 dried in the open air, weiglied 19^- grains. 



2. The muriatic acid solution, which had a deep yellow- Oxide of tita- 

 ish brown colour, was concentrated almost to dryness, and '^'"™' 



then diluted with water. It assumed a milky appearance; 

 but nothing was precipitated. Being boiled for some time, 

 and then set aside, a curdylike matter fell. It was of a 

 milk-white colour, weighed, when dry, 7 grains, and pos- 

 sessed the properties of oxide of titanium. 



3. The residual liquid being supersaturated with ammo- Oxide of iron, 

 nia, a dark reddish-brown matter precipitated, which being 

 separated by the filter, dried, drenched in oil, and heated 



to redness, assumed the appearance of a black matter^ 

 strongly attracted by the magnet. It weighed 93-7 grains^ 

 and was oxide of iron. -."^ ^;hmu 



4. The 19*5 grains of residual powder, being miked With 

 four times its weight of carbonate of soda, and exposed 

 for two hours to a red heat, in a platinum crucible, and 

 afterward heated with muriatic acid, was all dissolved j 

 except about a grain of blackish matter, which was set 

 asidev- ■■"'■■ .-■...= * — ■ ' 



5. The muriatic solution being coricentrated by evapora- More oxide •f 

 tion, a little white matter was separated. It weighed one tuamum. 

 fourth of a grain, and possessed the characters of oxide of 

 titanium. 



6. When evaporated to dryness, and redissolved in wa- Silex. 

 ter, a white powder remained, which proved to be silica, 



and which, after being heated to redness, weighed one 

 grain. ' ' ' < - 



7. The watety solution being supersatufed with potash, Aluminc 

 and boiled for a few minutes, was thrown upon a filter, to 

 separate a reddish-brown matter, which had been precipi- 

 tated. The clear liquid, which passed through the filter, 



was mixed with a solution of sal ammoniac. A soft white 

 matter slowly subsided. It was alumina, and, after being 

 heated to redness, weighed half a grain. 



8 Th« - 



