LANTHANIUM. 67 



hydrogen. The weighings of the metal were made in 

 vacuo to avoid possible reoxidation in displacing the gas by 

 air. The number is the mean of the experiments ; extreme 

 difference, 1.4 for O = 100. The ferric oxide was prepared 

 by incineration of the oxalate, moistening the residue with 

 nitric acid and reheating. [Erdmanii's Journ. fur Prak. 

 Chem., 33, 1844, 1.) 



L. E. RiYOT : SJ^M (0 = 16) ; 339.01 (0 = 100). 



Determined by two experiments on the reduction of pure 

 ferric oxide in a current of hydrogen. 100 parts of oxide 

 gave 69.31 and 69.35 parts metallic iron. [Annal. de Chim. 

 ei de Phys., (3,) 30, 1850, 188.) 



E. Maumene: S6.0016 (O = 16); 350.01 (0 = 100). 



Maumene made six experiments by dissolving iron wire 

 in aqua regia, precipitating with ammonia, heating the pre- 

 cipitate to redness and weighing. The number is the mean ; 

 extreme difference, 0.34. Maumene had convinced himself 

 by analysis of the extreme purity of the wire. {Erdmann^s 

 Journ. filr Prak. Chem., 51, 1850, 350.) 



J. Dumas : 56.2 (0 = 16). 



Two experiments on the precipitation of ferric chloride by 

 argentic nitrate gave each 28.1. A single experiment by 

 the same method on ferrous chloride which was sligbtly 

 yellow, gave 28.1. An experiment made on ferrous chlo- 

 ride, which had been heated in a current of hydrogen and 

 of HCl and was colorless, but contained metallic iron, gave 

 when the admixture was determined, 27.99. Dumas takes 

 Ag = 108 ; CI == 35.5. [Annal de Chim. et de Phys., (3,) 55, 

 18"59, 157.) 



LANTHANIUM. 



W. F. Hillebrand has determined the specific heat of 

 metallic lanthanium. It corresponds to an atomic heat of 

 6.23, if the atomic weight is taken at 139. {Poggend. Ann., 

 168, 1876,82.) 



Several investigations on the atomic weight of lanthanium 

 were made previous to Mosander's announcement of the 

 discovery of didymium. F. J. Otto found it 108.J/,1 shortly 

 after its discovery, and announced it in his translation of 



