278 Klaproth on the Chemical Analysis 



dissolved in dilute muriatic acid, evaporated to dryness, redis- 

 solved in water, and filtered ; there remained upon the filter 113 

 grains of silica. 



b. The muriatic solution was divided into two equal portions, 

 one of which was mixed with solution of muriate of baryta ; 50 

 grains of sulphate of baryta = 16.5 dry sulphuric acid were 

 obtained. 



c. The other half of the solution was precipitated by ammonia. 

 The precipitate consisted of alumina, which when purified, edul- 

 corated and ignited weighed 19 grains. 



D. 



One hundred grains were fused with 300 of nitrate of baryta ; 

 the resulting mass was softened with water, mixed with excess 

 of sulphuric acid, evaporated nearly to dryness, and then boiled 

 in water and filtered ; the clear liquid was neutralized by am- 

 monia, and after the separation of the precipitate was evaporated 

 to dryness and ignited, there remained 7 grains of sulphate of 

 potassa = 4 of pure poiassa. 



The components therefore are 



99. 



Analysis of the Alum Slate of Freienwald. 

 A. 



a. 1000 grains were boiled for half an hour with 20 ounces 

 of distilled water ; then filtered and the residue edulcorated. 

 The filtered liquid was colourless, did not change vegetable 

 blues, but had a slightly vitriolic taste . 



b. Half of this solution was mixed with muriate of baryta by 

 which 23 grains of sulphate of baryta were separated ; and after- 

 wards, prussiate of ammonia threw down 40 grains of prussiate 

 of iron. 



c. The other half was mixed with oxalate of potassa; it be- 



