cia 
until a second crop was gathe 
- determined in this way on a large p e 
_ lows: silica 68-84, glucina 13°40, alumina 16°47, sesquioxyd of 
iron 1°70. Total 100-41. : 
C. A. Joy on Glucinum and its Compounds. 91 
and caustic potassa be fused together, water dissolyes out noth- 
ing, but if alumina be fused in the same way, it will be ren- 
dered soluble in water. This suggested a method for the separa- 
tion of the two earths. Upon trial it was found that the glucina 
was equally soluble in water after fusion with caustic potassa. 
10. By formate of ammonia.—Formate of ammonia precipitates 
iron, alumina, and glucina, and none of them are soluble in 
excess. ‘This method was therefore not available. 
11. By the decomposition of sulphates.—If sulphate of glucina 
be heated to redness, sulphuric acid and sulphur are driven off, 
and the pure oxyd remains. The sulphate of manganese is not 
decomposed by heat in this way. This method may be of ap- 
plication in the analysis of helvine, but can not be used to sepa- 
rate alumina from glucina, as.the sulphate of alumina behaves, 
when heated, in the same manner as the sulphate of glucina. 
12. By the formation of potash-alum.—One part of finely pul- 
verized beryl was intimately mixed with two parts of carbonate 
of potassa, and fused in a capacious platinum crucible at an or- 
. dinary red heat. After cooling, concentrated sulphuric acid was 
poured over the mass, care being taken to prevent loss by effer- 
vescence, and the whole constantly stirred until it assumed a 
gelatinous condition. The excess of sulphuric acid was then 
expelled, and the silica determined as usual. The filtrate from 
the silica, containing the sulphates of alumina, glucina, iron and 
tassa, was concentrated by evaporation, and allowed to stand 
E po 
_ twenty-four hours, and sometimes longer, according to the 
_ amount of beryl taken, until a crop of alum crystals had formed. 
These were collected and washed, and the liquid evaporate 
red. The filtrate from the alum 
crystals was concentrated and poured into a hot saturated solu- 
_ tion of carbonate of ammonia, and allowed to stand several 
days with frequent agitation. The insoluble portion was col- 
ected on a filter and digested a second time in carbonate of 
e consideration of the salts of glucina is reserved for a 
_ future communication. 
Columbia College, New York, May, 1863. 
¢ 
