118 CHRYSOBERYLS FROM 



Three grammes of the mineral were examined under 

 the impression that Professor Klaproth's analysis was ac- 

 curately made. It was decomposed in the usual manner 

 with four parts of caustic potash, and subsequently treated 

 with diluted muriatic acid ; but the solution was imperfect. 

 The insolul)Ie matter was collected on a filter, and it 

 amounted to 25 or 30 per 100, It was repeatedly acted 

 on in the same way, and each time it diminished in quan- 

 tity, until the fourth experiment. It then weighed about 

 fifteen-hundreths, and thereafter resisted all furthei' efforts 

 to rend<r it soluble by these means. This residue was 

 then boiled in concentrated sulphuric and muriatic acids, 

 but neither of them dissolved more than one-third of it. 

 These solutions were tested by different re-a^ents, and great- 

 ly to my surprise, the addition of subcarbonate of ammonia 

 occasioned afloculent precipitate, which entirely re-dissolved 

 in an excess of the alkaline subcarbonate. 1 immediately 

 suspected the presence of Glucina, but was much at a loss 

 to explain its insolubility, until I observed Berzelius's analy- 

 sis of the Eticlase,* in which he met witii a compound of 

 glucina and oxide of tin that obstinately resisted acids. He 

 also met with refractory combinations of tliis eartli and the 

 oxides of manganese and cerium. I next endeavoured to dis- 

 solve the compound by the acid sulphate of potash ; but this 

 method did not succeed. I was not more successful with the 

 nitric and nitromuriatic acids ; nor could it be dissolved by 

 means of boric acid. Berzclius having discovered colum- 

 bium in the gangue of the cymophane from Haddam, tlie 

 insoluble residue was tested for the oxide of that metal, but 

 all my attempts were fruitless. At length, I supposed, that 

 as barytes could be brought into contact with this substance 

 more conveniently than potash at a high temperature, it 

 might decompose it. With this view, a portion of the inso- 

 luble matter was exposed to a strona; heat, during one hour 

 with six parts of nitrate of barytes in a platina crucible. 



* Nouveau Systeme de Mineralogie, p. 289. 



