298 EARTHS. 



SEC. VIII. GLUCINA. 



1. NAME NATURAL HISTORY DISCOVERY. 



From /Xuxuj, sweet, because its salts have that taste. Discovered 

 in the beryl and emerald, in 1798, by Vauquelin, who at the request 

 of Haiiy, analyzed the beryl to discover whether its chemical in- 

 gredients were the same with those of the emerald, as from physical 

 considerations, he had conjectured that they were. The analysis 

 proved the suspicions of Haiiy to be well founded. 



2. PROCESS. (Th. I, 530.) Fuse pulverized emerald or beryl 

 1 part, with potassa 3 parts ; dilute the mass with water, dissolve in 

 muriatic acid, and evaporate to dryness, stirring the matter towards 

 the end. Mix it with much water, and filter to separate the silica, 

 which is more than half. The muriates of glucina and alumina are 

 in solution ; precipitate them by carbonate of potash,* wash the pre- 

 cipitate, and dissolve it in sulphuric acid. Add to the solution sul- 

 phate of potash ; evaporate and obtain crystals of alum. When no 

 more are formed by adding sulphate of potash, add carbonate of 

 ammonia in excess, shake the mixture, and let it stand till the gluci- 

 na is dissolved by the carbonate of ammonia, and nothing but alumina 

 is left, then filter, and evaporate to dryness, when a white powder is 

 obtained, which, after slight ignition in a crucible, is glucina, in the 

 proportion of 16 per cent, of the stone. Euclase also contains 21.78 

 of this earth ; and by Mr. Seybert's analysis, the chrysoberyl of both 

 Haddam and Brazil, has as much as the emerald, f that is 15.80 

 glucina for the chrysoberyl of Haddam, and 16, for that of Brazil ; 

 the other constituents were for the latter, alumina 68,66, silica 5.99, 

 oxide of titanium 2.66, oxide of iron 4.73, and water ; for that of 

 Haddam, 73.66 alumina, 4 silica, 1 oxide of titanium, 3.38 oxide of 

 iron, and a little moisture. The existence of glucina in chrysoberyl 

 had been overlooked by the first analysts, until it was discovered by 

 Mr. Seybert. 



3. PROPERTIES. 



(a.) Inodorous, tasteless, and insoluble in water ; but forms with 

 it a paste of some tenacity. It is a fine white powder, resembling 

 alumina, and like that adheres to the tongue. 



b.) Does not contract in the fire, nor affect the test colors. 



c.) Specific gravity 3. 



d.) Infusible by the common blow pipe, but perfectly fusible by 

 that of Dr. Hare. 



* The latter part of this process may be conducted differently from the descrip- 

 tion in the text. After precipitating the alumina and glucina, dissolve them in water 

 acidulated by muriatic acid, and precipitate again by pure ammonia; then dissolve 

 this in carbonate of ammonia, and proceed to the end as already directed. Or, start- 

 ing from the same point: add to the precipitated earths pure potassa, which will dis- 

 solve the alumina, and a portion of the glucina, but that which remains, is this earth 

 sometimes slightly colored by iron. For the mode of extracting glucina from the 

 chrysoberyl, see Am. Jour. Vol. Vill,p. 105. I Am. Jour. Vol. Vlll, p. 105, 



