140 PottoKk—On the Extraction of Glucinum from Beryl. 
cent. was subsequently reprecipitated. The investigation of this phenomenon, of 
reprecipitation from caustic potash, finally led to the discovery of the new earth 
elucina. 
In the year 1843 Awdejew* made an analysis of the chloride and sulphate, 
and thence deduced for the equivalent of glucinum the figure 4°64. 
The hydrate, basic carbonate, and sulphate were carefully analysed by 
Weeren in 1854,+ the glucina being purified by fractional solution in ammonium 
carbonate, to remove the last traces of alumina. 
Debray,t in 1855, again analysed the sulphate, by ignition in a platinum 
crucible, alone, and with lime, from which he deduced both the water and 
sulphuric acid. He also analysed the basic carbonate and a number of other 
compounds. 
A large number of methods of decomposing beryl, and separating glucina, were 
tried by Joy§ in 1863. The method finally adopted was to fuse with alkaline 
carbonates, decompose with sulphuric acid, crystallize out most of the alum, and 
separate the glucina from the mother-liquors by pouring it into an excess of 
ammonium carbonate, then to boil out the glucina. 
The paper on the specific heat of glucmum by Reynolds|| in 1877 was the 
beginning of a brilliant series of papers, by various authors, on the atomicity of 
glucinum. Those by Nilson and Pettersson,4{ and Humpidge,** on the specific 
heat of the metal, and by Nilson and Petterssont+ on the vapour density of the 
chloride, are perhaps the most important. Nilson and Pettersson long maintained 
that glucinum was trivalent ; and it is interesting to note how their own paper, 
on the vapour density of the chloride, finally set the matter at rest, and proved 
that glucinum was divalent. 
Marignactt investigated the properties and composition of the fluoride and 
double fluorides of glucinum in 1873. In 1890 Kruss and Moraht§§ contributed a 
long paper on the extraction of glucina and preparation of glucinum by reduction 
of the fluoride with sodium, and they point out the anomalous behaviour of some 
substance contained in the ammonium sulphide precipitate. 
The analytical side of the question has been dealt with by C. Réssler,||\| in his 
paper on the separation of aluminium and glucinum by phosphate of ammonia. 
* Ann. Chim. Phys., [3], vol. vii., 1848, p. 155. | ** Roy. Soc. Proc., vol. xxxviii., 1885, p. 188. 
+ Pogg. Ann., vol. xcii., 1854, p. 91. ++ Compt. Rend., vol. xcyiil., 1884, p. 988. 
+ Ann. Chim. Phys., [3], vol. xliv., 1855, p. 5. tt Ann. Chim. Phys., [4], vol. xxx., 1873, p. 45. 
§ Amer. Journ. Sci., [2], vol. xxxvi., 1863, p. 83. §§ Ber. Deutsch. Chem. Gesell., Jahrg. xxiii., 1890, 
|i Phil. Mag., [5], vol. i1., 1877, p. 38. p. 727a, p. 25526. 
s| Compt. Rend., vol. Ixxxvi., 1878, p. 823. |||| Zeitsch. Anal. Chem., vol. xvil., 1878, p. 148, 
