130 CHRYSOBERYLS FROM 



of it could be detected. To the remaining liquor a consi- 

 derable excess of subcarbonate of ammonia was added, and 

 the precipitated matter was digested twenty-four hours. It 

 was then separated by filtration, and the fluid was boiled till 

 all the ammonia was expelled. No glucina was thus pre- 

 cipitated. Hence we conclude, that the very small portion 

 of titanium above mentioned, rendered tiie whole of the glu- 

 cina so refractory. The alumina precipitated by the sul>- 

 carhonate of ammonia was mixed with a small quantity of 

 oxide of iron. It was soluble in caustic poiash, and with 

 this alkali and sulphuric acid it gave regular octsedral crys- 

 tals of alum. The liquor, when tested with phosphate of 

 soda and ammonia, was found to contain no Magnesia. 



After the preliminary experiments, I commenced the fol- 

 lowing 



ANALYSIS OF THE CHRYSOBERYL FROM HADDAM. 



A. Five grammes of the mineral, reduced to small frag- 

 ments in an iron mortar, were carefully porphyrised in one 

 of agate, from which it acquired the additional weight of 

 0.13 grammes. The 5.13 grammes were then exposed to 

 a red heat, and thereby suffered a diminution of 0.40 per 

 100. 



B. The calcined mineral {A) was heated, during one hour, 

 in the silver crucible, with caustic potash, and the product 

 was treated with diluted muriatic acid ; the solution was of 

 a lemon yellow colour. There remained a white insoluble 

 residue, which after calcination weighed 1.47 grammes. It 

 was repeatedly calcined with caustic potash, and treated with 

 diluted muriatic acid, with tlie following results : 



After the 2d experiment, it weighed 0.97 grammes, 

 3d 0,89 



4th 0,85 



