BARIUM. 13 



pletely in chlorine, and boiled between 134° and 135°. 



(Paris Comptes Rend., 20, 1845, 1047.) 



J. Dumas : 74.94 (O = 16). 



Determined by four experiments on the titration of arsenic 

 ter-chloride with argentic nitrate, the ter-chloride being 

 prepared in several lots. The number is the mean of the 

 experiments; the extreme difference being 0.15. Dumas 

 takes Ag = 108 ; CI = 35.5. [Annal. de Chimie et de Physique, 

 (3,) 65, 1859, 174.) 



F. Kessler: 75.2 (O = 16). 



In six experiments arsenious acid was titrated with potas- 

 sic bichromate and counter-titrated with ferrous chloride. 

 The number so obtained was 75.15. In twelve experiments 

 a known weight of arsenious acid was oxidized in caustic 

 potash solution by potassic chlorate, the arsenious acid be- 

 ing slightly in excess, acidified with chlorhydric acid and 

 the excess of arsenious acid titrated with potassic bichro- 

 mate and counter-titrated with ferrous chloride. The oxi- 

 dizing action of the potassic bichromate was experimentally 

 determined. The number obtained from these experiments 

 was 75.24. Five experiments were made with acid instead 

 of alkaline solutions of arsenious acid; they gave 75.15. 

 The arsenious acid was colorless, transparent, volatilized 

 without any residue, and was thoroughly dessicated. Kess- 

 ler assumed K = 39.12; 01 = 107.97. [Poggend. Annal., 

 95, 1855, 210; 113, 1861, 140.) 



BARIUM. 



The specific heat of barium compounds, especially of the 

 chloride, as determined by Regnault and by Kopp, shows 

 that the atomic weight of this element lies in the neighbor- 

 hood of 137. {Gmelin-Kraut, I. c.) 



WoLLASTON and Klaproth . 139.2 (O = 16) ; 870 

 (0 = 100). 



Klaproth found that 100 parts of carbon di-oxide were 

 equivalent to 352.57 parts barium oxide, and that 34 parts 

 sulphuric anhydride were equivalent to 66 parts of barium 



