the Elie Pyrope or Garnet. 211 



dissolved in muriatic acid, and muriate of ammonia, and ex- 

 cess of ammonia added. Some wliite gelatinous matter fell, 

 which, by ignition, got a greenish-yellow tint, magnesia be- 

 ing left in solution. The ignited precipitate was again dis- 

 solved in muriatic acid, and treated with muriate of ammonia 

 and excess of ammonia, which caused once more a gelatinous 

 precipitate. This was dissolved to a great extent by boiling 

 with caustic potash, leaving some matter, which was prin- 

 cipally oxide of iron, but gave a permanent fine, although 

 pale, emerald-green to salt of phosphorus, and, therefore, 

 contained a trace of oxide of chrome. The caustic potash, 

 treated with muriatic acid and carbonate of ammonia, yielded 

 a white gelatinous precipitate, which gave the fine blue of 

 alumina, with nitrate of cobalt. In short, the white residue 

 of incineration, consisted of magnesia, alumina, a very little 

 oxide of iron, and a trace of oxide of chrome. 



The other necessary and usual steps were then taken to 

 separate the difi"erent constituents of the mineral, the lime 

 being thrown down by oxalate of ammonia, and the magnesia 

 by boiling with carbonate of potash. 



A farther search was made for chrome, by fusing a portion 

 of the mineral with carbonate of soda and a little nitre ; but 

 none was found in this way when the fused mass was treated 

 with water, and duly examined. 



The only attempt made to ascertain the state of oxidation 

 of the iron, was by digesting a portion of the finely powdered 

 mineral with muriatic acid in a close vessel, and then testing 

 it, after neutralization with ammonia, by the two prussiates 

 of potash. The reaction was decidedly that of peroxide, and 

 not at all of protoxide. 



In the twenty grains of the mineral there were found — 



In 100. Oxygen. 



Silica, . . . 8-560 42-80 22-23 4 



Alumina, . . 5-730 28-65 13-381 



Peroxide of iron, . 1-863 9-31 2-85/ 



Protoxide of Manganese, 0050 0-25 -05) 



Lime, . . . 0-956 4-78 1-35 > 



Magnesia, . . 2-135 10-67 4-10) 

 Oxide of chrome, trace, 



19-294 96-46 



3 



