40 



XIumuM. 



Metallic ox- 



til 



EXPlfRINENTS aN ILLANITS; ' 



pfiwd«r in an agate tnoriar, were digested repeatedly on t 

 f^nd bath ia muriatic acid, till the liquid ceased to have 

 any a6iion on it. The undissolved residue was silica, mixed 

 with some fragments of mica. When heated to redness, it 

 weighed 33*4 j^rains. 



2. The muriatic acid solution was evaporated almost t» 

 dryness, to get rid of the excess of acid, dissolved in a laroje 

 quantity of water,, mixed with a considerahle excess of car- 

 bonate of ammonia, and boiled for a few minutes. By this 

 treatment, the whole contents of the mineral were precipi- 

 tated in the state of a yellowish j)0wdt'r, which was sepa- 

 rated by the filter, and boiled, while still moist, in potash 

 lie. A small portion of it only was dissolved. The potash 

 lie was separated from the undissolved portion by the tiltre, 

 and inixed with a solution of sal ammoniac, by raeans of 

 which a white powder precipitated from it. This white 

 matter, being heated to redness, weighed 7*9 grains. It 

 was digested in sulphuric acid, but 3*76 grains refused to 

 dissolve. This portion pobsessed the properties of silica, 

 iThe dissolved portion, being mixed with a few drops of sul- 

 phate of potarih, shot into crystals of alum. It was therefore 

 alumina, and amounted to 414 grains. 



3. The yellow matter, which refused to dissolve in the 

 potash lie, was mixed with nitric acid. An effervescence 

 took place, but the licjnid remained muddy, till it was ex^ 

 posed to heat, when a clear reddish-brown solution was ef^ 

 fectcd. This solution was evaporated to dryness, and kept 

 for a few minutes in the temperature of about 400**, to per- 

 oxidize the iron, and render it insoluble. A sufficient quao- 

 tity of water was then poured on it, and digested on it for 

 half an hour, on the sand bath. The whole was then 

 thrown upon a filter. The dark red tnatter,"which re- 

 niained on the filter, was drenched in oil, and heated to red- 

 ness, in a covered crucible. It was then black, and at- 

 tracted by the magnet; but had not exactly the appear- 

 ance of oxide of iron. It weighed 42i*4 graiiiS, 



4. The liquid, whicb passed through the filter, had not 

 the sweet taste which I expected, but a slightly bitter onV, 

 siniilar to a weak solution of nitrate of lime. Hence it was 

 clear* that no yttria was present, as there ought to have 



