BARIUM. 15 



— . Salvetat: 136 (0 = 16); 850 (0 = 100). 



Determined from the loss of weight ensuing on the de- 

 composition of barium carbonate by sulphuric acid. Details 

 not given. {Paris Comptes Hendus, 17, 1843, 318.) 



J. Pelouze : 137.28 (O = 16) ; 858.01 (O = 100). 



Into a nitric acid solution of a known weight of perfectly 

 pure silver, a known and slightly more than equivalent 

 weight of barium chloride was introduced. The excess 

 was titrated with decimal silver solution. The value is the 

 mean result of three experiments, which give an extreme 

 difference of 0.22 for O = 100. The barium chloride was 

 purified by recrystallizations continued till determinations 

 gave a constant result, and was dessicated in part at 200°, 

 and in part at a temperature just below redness. Pelouze 

 took Ag = 1349.01, and CI = 443.2. {Paris Comptes Rendus, 

 20, 1845, 1047.) 



C. Marignac: 137.08 (0 = 16); 856.77 (0 = 100). 



Determined by six experiments on the equivalence of sil- 

 ver and barium chloride performed by Pelouze's method, 

 {vide supra.) 100 silver were found equivalent to 96.365 

 barium chloride ; extreme difference, 0.038 ; hence the value 

 taken. Marignac takes Ag = 1349.01, and CI = 443.2. The 

 barium chloride was purified as follows : Commercial chlo- 

 ride was crystallized from boiling aqueous solution ; the 

 crystals were heated to redness, dissolved in boiling water, 

 treated with carbon di-oxide, filtered and crystallized, and 

 these crystals were washed with alcohol and again recrystal- 

 lized. Determinations were made at each stage and the 

 purification was continued until constant results were ob- 

 tained. {Liebig, Annal., 68,1%^'^, 214:', Bibl. Univ., Arch, des 

 Sciences, 8, 265.) 



H. Struve: 136.26 (0 = 16). 



100 parts of barium chloride gave 112.0938 parts of sul- 

 phate as a mean of two experiments; extreme difference, 

 0.005. S = 32; 01 = 35.4624. {Liebig, AnnaL, 80, 1851, 

 204; Oefversigt af Kongl. vet. Acad. Foehr., 6, 165.) 



T. Andrews : 137.578 (O = 16). 



Andrews obtained this number from two nearly coinci- 

 dent experiments of which he gives no details. iBrit. Assoc. 

 Hep., 1852, pt. 2, 33.) 



