GLUCINUM. 525 



S ECTION XI. 



GLUCINUM, YTTRIUM, THORIUM, ZIRCONIUM. 



GLUCINUM. 

 Eg. 331.3 or 26.51; G. 



The compounds of this metal have a considerable analogy to 

 those of aluminum. Glucinum is obtained from its chloride, 

 which is decomposed in the same manner as that of aluminum. 

 This metal is fusible with great difficulty, not oxidable by air or 

 water at the usual temperature, but it takes fire, in oxygen, at 

 a red heat, and burns with a vivid light. It derives its name 

 from y\vKvs, sweet, in allusion to the sweet taste of the salts of 

 its oxide glucina. 



Glucina (G 2 O 3 ) is a comparatively rare earth, but is con- 

 tained to the extent of 13| per cent in the emerald or beryl, of 

 which specimens that are not transparent or crystallized, can be 

 procured in considerable quantity. To decompose this mineral, 

 which is a silicate of glucina and alumina, it must be reduced to 

 an extremely fine powder, the grosser particles which fall first 

 when the powder is suspended in water, being submitted again 

 to pulverization, and the powder fused with 3 times its weight 

 of carbonate of potash. The calcined mass is moistened with 

 water, and then treated with hydrochloric acid, added in small 

 portions till it is in excess. The potash, alumina and glucina 

 are thus converted into chlorides, and dissolved. The solution 

 is evaporated to dryness on a water-bath, and the residue acidu- 

 lated by a few drops of hydrochloric acid : the silica remains 

 undissolved. The alumina and glucina are afterwards preci- 

 pitated together from the solution, by ammonia ; and after 

 being well washed, but without being dried, the mixt oxides 

 are digested in a large quantity of carbonate of ammonia, which 

 takes up the glucina without touching the alumina. The liquor 

 is filtered, and the carbonate of ammonia being then expelled 

 from it by ebullition, carbonate of glucina precipitates. The 

 earthy carbonate is ignited, and leaves glucina in the state of 

 a white and light powder, tasteless, infusible, insoluble in water 

 and ammonia, but soluble in potash and soda. Its density is 

 nearly 3. It is distinguished from alumina, by forming a car- 

 bonate, and being soluble, when freshly precipitated, in a cold 

 solution of carbonate of ammonia. 



