152 BERYL. 



is then filtered off, the solution concentrated by evapo- 

 ration, and dropped very gradually, with constant stir-' 

 ring, into an excess of a warm concentrated solution 

 of carbonate of ammonia, which precipitates the alu- 

 mina, and dissolves the berylla (glucina). When the 

 precipitate has been digested for some time with the 

 solution in a closed vessel, the solution is filtered off, 

 boiled for a long time, until the greater part of the 

 carbonate of ammonia is expelled, slightly acidified 

 with hydrochloric acid, digested for some time to 

 expel the carbonic acid, and the glucina finally pre- 

 cipitated by caustic ammonia. 



Pure. glucina may be prepared in the following 

 manner. The mineral is heated to redness, and then 

 thrown into cold water, when it may be more easily 

 pulverized. 7 parts of the powder are mixed with 

 13 parts of finely-powdered fluor spar, and 18 parts of 

 concentrated sulphuric acid, and warmed until no 

 more fluoride of silicium is given off. The mass is 

 then gently ignited, digested for some time with water, 

 and the sulphate of lime filtered off. 2 parts of sul- 

 phate of potassa are then added and the solution 

 evaporated to crystallization, when the greater part of 

 the alumina crystallizes as alurn. Acetate of soda is 

 then added to the solution, and by boiling the remain- 

 der of the alumina and the sesquioxide of iron are 

 precipitated. The glucina is precipitated from the fil- 

 tered solution by ammonia. 



If hyposulphite of soda precipitates alumina alone, 

 and no glucina, in a neutral solution of the two ba^es, 

 this method may be used for their separation.* 



* See Silliman's Journal, vol. xxxvi., Prof. C. A. Joy on Glu- 

 cinum and its Compounds. 



