26 ATOMIC WEIGHT DETEPwMINATIONS. 



spectroscopical]}' pure. The aluminium was removed with 

 ammonia, the sulphuric acid with barium chloride and 

 traces of barium with ammonium carbonate. The csesium 

 chloride, which was not deliquescent, was dried at 150°. 

 {Liebifs Annal, 181, 1876, 185.) 



CALCIUM. 



Bunsen has determined the specific heat of calcium. It 

 corresponds to an atomic weight of 40. {Gmdin-Kraut, L c.) 



F. 11. Wollaston: 4,0 J36 (0 = 16); 254.6 (0 = 

 100). 



Wollaston found that 43.7 parts of carbon di-oxide satu- 

 rated 56.3 parts of lime. If C = 75.4, the value follows. 

 {PhiL Trans., 104, 1814, 20.) 



J. J. Berzelius : 40.32 (O = 16) ; 252.075 (O = 100). 



301 parts of anhydrous calcium chloride gave 775 parts 

 argentic chloride. If CI = 443.28 and Ag = 1349.66 the 

 value follows. This analysis, made in 1818, was erroneously 

 calculated from a mistake in setting down its results and 

 the atomic weight of Ca was taken at 256.019. [Poggend. 

 Annal.,8, 1826,189; and Lehrbuch der Chemie, 5th cd., 3, 

 1227.) 



•J. Dumas: 40 (0 = 16). 



Three experiments were made on the calcination of cal- 

 cium carbonate which contained 0.03 per cent, of ferric oxide 

 and silicic acid. The weight of the residue was in mean 

 56.07, or, subtracting 0.03, 56.04, with an extreme difference 

 of 0.08. These figures give almost exactly 40. The weigh- 

 ings are reduced to vacuum. {Paris Comptes Rendus, 14, 

 1842, 537.) 



— . Salvetat : 40 (0 = 16) ; 250 (O = 100). 



It is to be inferred from the context that this determina- 

 tion was made from the loss of weight ensuing on the de- 

 composition of calcium carbonate bv heat or sulphuric acid. 

 {Paris Comptes Pendus, 17, 1843, 318.) 



