134 ATOMIC WEIGHT DETERMINATIONS. 



Bahr and Bunsen : 61.7 (O = 16). 



Determined by saturating the oxide with sulphuric acid 

 as in the determination of erbium, q. v. Partial recrystal- 

 lization does not produce pure yttrium nitrate, but only 

 concentrates traces of didymium in the salt. Didymium 

 must be separated with potassic sulphate. Erbium nitrate 

 is more easily decomposed by heat than yttrium nitrate. 

 The nitrates were therefore partially decomposed, yttrium 

 nitrate dissolved out and the process repeated until there 

 was no trace of erbium or didymium visible in the spectro- 

 scope. The mean of two determinations gave Y = 30.85 ; 

 diflerence, 0.1. S = 16. [Liebig's Ann., 137, 1866, 21.) 



M. Delafontaine : 58.5 (0 = 16). 



Determined by three experiments on the sulphate which 

 gave in mean 48.28 per cent, oxide for S = 32. [In the 

 Jahresbericht this determination is reported as giving Y = 

 74.5. Yttrium is apparently a misprint for yttrium oxide.] 

 The yttrium salt seems to have been prepared according to 

 the method of Bahr and Bunsen. {Kopp's Jahresbericht, 

 1866, 184; Bibl. Univ., Arch, des Sciences, (2), 26, 1866, 112.) 



P. T. Cleve and O. M. Hoeglund : 59.7 (0 = 16). 



Determined by analysis of the sulphate. The oxide was 

 purified by heating the nitrates, etc., according to N". J. 

 Berlin. (Blomstrand, in Berlin, Bericht der Chem. Ges., 

 1873, 1467; Bihang till Vet. Akad. Handl, 1873, B. 1, 3, 

 No. 8.) 



ZINC. 



The specific heat of zinc has been determined by Regnault 

 and others. The vapor density of volatile organic com- 

 pounds has been determined by Frankland and others. 

 These experiments agree in placing the atomic weight at 

 about 65. {Gmelin- Kraut, I. c; L. Meyer, I. c.) 



Gay-Lussac, Berzelius, TVollaston : 65.54-7 (0 = 

 16) ; 4.09.67 (O = 100). 



In his experiments on the oxidation of zinc Gay-Lussac 



