22 Chemical Examination of American Minerals. 



swam in flocks through the liquid ; and which when collect- 

 ed, dried and ignited, weighed 0*67 grains. Hence the 

 weight of the alumina dissolved should have been G-38 grains. 

 Being precipitated from the potash solution, by neutralizing 

 the potash with muriatic acid, and then adding carbonate of 

 ammonia in slight excess, it weighed after edulcoration and 

 ignition 6*30 grains. Tl)e 0-02 grain of loss, (if no error 

 was committed in the analysis) might be owing to some sul- 

 phuric acid having adhered to the precipitated alumina. 



3. The 0-67 grains of dark reddish matter, which had 

 refused to dissolve in the caustic potash, was treated with 

 muriatic acid. A slight effervescence took place, and the 

 whole dissolved except 0*012 grains, which was whitish, with 

 a shade of red. This residue was too small to admit of ex- 

 amination. 1 consider it as silica not quite free from oxide 

 of iron. 



4. The muriatic solution was made as neutral as possible, 

 and oxalate of ammonia being dropt into it, a white precipi- 

 tate fell, which when well washed and dried weighed 0-31 grs. 

 It was oxalate of lime, and equivalent to 0*136 grains of lime. 



5. Benzoate of ammonia now threw down a white precipi- 

 tate, which after edulcoration, drying, drenching in nitric 

 acid, and ignition, weighed 0*11 grain. It was peroxide of 

 iron. 



6. The liquid thus freed from lime and iron was put into a 

 flask, mixed with carbonate of soda, and boiled for some 

 time. A precipitate fell in white flocks, which gradually be- 

 came yellow. It was, therefore, carbonate of manganese. It 

 is obvious that the whole protoxide of manganese in the matter 

 subjected to analysis, was 0*67 — 0*247=0*423 grains. A 



