Examination of Hi/alosideriie, a new Mineral. 187 



This precipitate, after calcination, amounted to 0*023 gramm. 

 and had the properties of pure alumina. 



d.) The fluid (b), from which the iron and argillaceous earth 

 had been precipitated, and which did not become turbid by 

 the addition of oxalate of potassa,was again acidulated, evapo- 

 rated to the requisite degree, and precipitated at a boiling tem- 

 perature with carbonate of soda. The precipitate dried and 

 strongly calcined gave 0*277 gramm. of magnesia, which, af- 

 ter being dissolved in dilute nitric acid, left 0*005 of oxide of 

 manganese. 



e.) The magnesia still contained in the remaining fluid of 

 (d), after that had been previously neutralized with muriatic 

 acid, and sufficiently concentrated, was precipitated by means 

 of carbonate of ammonia and phosphate of soda; by which 

 0*1 64 gramm. of calcined phosphate of magnesia were ob- 

 tained, which answer to 0*065 gramm of pure magnesia. 



B. 



In order to determine the proportion of potassa in the hy- 

 alosiderite, 0*567 gramm. of the mineral were treated with 

 muriatic acid ; the iron, alumina, magnesia, silica, and man- 

 ganese, separated in the usual manner, the remaining solution 

 evaporated to dryness, and the residuum calcined in a pla- 

 tinum crucible. What remained was dissolved in distilled wa- 

 ter, and treated with muriate of platinum, and thus gave 0*055 

 gramm. of the triple salt =0*016 gramm. pure potassa. 



C. 

 As the relative effect of glass of borax in the treatment with 

 tin seemed to indicate the presence of chrome in this mineral, 

 a quantity of it, exactly weighed, was fused with nitrate of 

 potassa in order to discover that metal. The melted mass 

 was of a yellowish-brown colour with some grass-green streaks 

 which originated from sub-manganesate of potassa. The so- 

 luble part was now properly extracted with water, the fluid 

 thus obtained carefully neutralized with nitric acid, and then 

 treated with a solution of protonitrate of mercury, on which 

 a slight reddish turbidness merely took place, so that the 

 quantity of chrome could not be ascertained. 



According to this analysis, 1*040 gramm. of hyalosiderite, 



yield Silica (a) 0*329 gramm. 



Protoxide of iron (b) ... 0*309 



Magnesia (d) 0*272 



Ditto (e) 0*065 



Alumina (c) 0*023 



Oxide of manganese (d) . . 0*005 



Potassa (B) 0*029 



Traces of chrome 



A a 2 1*032 



