156 Analysis of a Manganesian Garnet, 



fore, the moisture expelled by this treatment, was 0.02 

 grammes on 3 grammes, or 0.66 per 100. 



B. The residue of the preceding calcination, (A) was 

 calcined, at a red heat in a platina crucible, during 30 min- 

 utes with 15grammes of sub carbonate of Soda, the mixture 

 did not enter into fusion, but merely assumed a pasly con- 

 sistence ; when cold the mass was of a very deep green 

 colour, the water which was used to detach it from the cru- 

 cible was also intensely green — an indication of a large 

 quantity of Manganese. When an excess of muriatic acid 

 was added to the liquor, chlorine was abundantly disenga- 

 ged, the solution was not perfect until the evaporation of 

 the liquor was considerably advanced, it was then of a deep 

 orange colour; to effect the separation of the silica it was 

 evaporated in the usual manner to a dry gelatinous mass, 

 then treated with water, acidulated with muriatic acid, and 

 again moderately evaporated; more water was added, and 

 the solution was filtered; the silica remaining on the filter, 

 after edulcoration and calcination, weighed 1.075 grammes 

 on 3 grs. or 35.83 per 1 00. 



C. The silica having been separated, (B) the excess of 

 acid was neutralized with caustic potash, the solution was 

 treati d with hydro-sulphate of potash, this occasioned a 

 precipitate, which at first was black, but the latter portion 

 of it was nearly colourless. The precipitate was well wash- 

 ed and dissolved, in the humid state, in nitro-muriatic acid, 

 the solution was evaporated to dryness to expel the excess 

 of acid, the residue was treated with water, and boiled dur- 

 ing one hour and a half with an excess of caustic potash, 

 the filtered liquor was treated with an excess of muriatic 

 acid, then by ammonia there was formed a precipitate of 

 alumina, which, after being washed and eJtposed to a red 

 heat, weighed 0.542 grammes on 3 grammes, or 18.06 per 

 100. 



D. The residue, which was separated from the alcaline 

 liquor, (C) was of a dark red colour; it was treated while 

 humid, with acetic acid, the solution was evaporated, at a 

 moderate temperature, to perfect dryness, the dry mass was 

 treated with water, the peroxide of iron, collected on a 

 filter, proved to be free from alumina and manganese, it 

 weighed 0.486 grammes; a portion of the pulverized min- 

 eral was treated with nitric acid and calcined ; the powder, 

 which was flesh coloured, now became nearly black, this 



