I^O STONE CONTAINING POTASH. 



Analyfis of a . Exp, VII I. — The precipitate of this experiment was difToIved 

 ftone containing jj^ tiitro-muriatic acid, and then mingled with liquid am- 

 monia. A brown precipitate became depofited, which, 

 after being dried, amounted to 0,25 grains. It was oxide of 

 iron. 



The fluid from which this iron had been feparated, yielded 

 no other produds, on being carefully examined, except two 

 grains of (ilex which efcaped feparation. 



Thus far the ftone had yielded filiceous earth, alumina and 

 oxide of iron. I fliall fupprefs thofe enquiries which proved 

 fruitiefs for learning its farther compofition, and ftate merely 

 thofe which were attended with fuccefs for that purpofe, and 

 which were as follow : 



Exp. IX. — One hundred grains of the flone reduced to an 



impalpable powder, were triturated with 600 grains of cryf- 



tallized nitrate of bary tes : the mixture fufed till the flame of a 



■ piece of ignited wood did not become enlarged when held 



clofe over the furface of the fufing mafs. 



Exp. X. — The melted mafs was foftened with water, and 

 digefted in muriatic acid j the fluid filtered, and the refidue 

 waflied. 



Exp. XL — The liquid obtained in this procefs I neutralized 

 with carbonate of ammonia, and added the latter till no further 

 cloudinefs enfiied. After having feparated the precipitate, I 

 evaporated the fluid to drynefs : the obtained fait I transferred 

 into a glafs tube clofed at one end, and committed it to fubli. 

 mation. 



Exp. XII. — After the fublimation had ceafed (which was 

 known by a metallic wire introduced into the tube during the 

 procefs, not becoming in the leafl covered with a coat ©f 

 fait), I broke the tube and feparated the fait. This being 

 diflblved in water and cryiiallized, yielded nine grains of mu- 

 riate of foda. 



Exp. XIII.— To decompofe this fait, I redifl^olved it in 

 water, and mingled the folution with nitrate of filver till no 

 farther cloudinefs appeared: I then feparated the muriate of 

 fdver formed, and decompofed the nitrate of potafli by heat, 

 which yielded 4,50 of potafli. 



The 



