28 ATOMIC WEIGHT DETERMINATIONS. 



difference 0.047. [Erdmanyi's Journ. fiir Pmk. Chemie, 31, 

 1844, 268.) Another experiment, in which the absence of 

 water was proved, gave 56.03 lime. The weighings are re- 

 duced to vacuum. {Erdmami's Journ. fiir Frak. Chem., 37, 

 184G, 77.) 



J. J. Berzelius : 40£64. (O = 16) ; 251.651 (0 = 

 100). 



Five experiments were made on the conversion of caustic 

 lime into sulphate. The value is the mean for S = 200.75 ; 

 extreme difference 0.962 for O = 100. The lime was care- 

 fully purified and burnt, but Berzelius says nothing of test- 

 ing it for carbonic acid, upon which Erdmann and Marchand 

 found an objection. Berzelius expresses himself ill satisfied 

 with the results. {Liebig's AnnaL, Ifi, 1843, 241; also 

 Lehrbuch der Chemie, 5th ed., 3, 1228.) 



J. Dumas : 40.02 (0 = 16). 



Five experiments were made on the titration of calcium 

 chloride with argentic nitrate. They give a mean of 20.065, 

 but Dumas considers only three of them as entitled to a 

 voice. These give 20.01; extreme difference, 0.03. The 

 calcium chloride was prepared by dissolving marble in 

 chlorhydric acid, digestion with lime water, filtration, 

 evaporation, treatment with chlorhj'dric acid and heating 

 in a current of chlorine. For the three experiments 

 averaged the chloride was kept melted in the current of gas 

 for from 8 to 10 hours. Ag = 108 ; CI = 85.5. {Annal. de 

 Chimie et de Physique, (3,) 65, 1859, 129.) 



CARBON. 



The specific gravity of gaseous carbon compounds shows 

 that the atomic weight must be nearly 12. [Gmelin- Kraut, 

 I. c.) Weber has shown that the specific heat of carbon at 

 high temperatures obeys Dulong and Petit's law. 



F. H. Wollaston: 12.06J^ (0 = 16); 75.4 (O = 100). 



Biot and Arago found the specific gravity of carbon di- 

 oxide 1.5196, and that of oxygen, 1.1036. Calculation from 

 these data gives the value. {Phil. Trans., 104-, 1814, 20.) 



