MERCURY. 81 



acid, converted into red oxide, dissolved in chlorbydric acid 

 and alcohol, precipitated with ammonium carbonate, dis- 

 solved in sulphuric acid, repeatedly heated to redness and 

 recrystallized, and was dried at 300°. Accurate experi- 

 ments on the reduction of the red oxide proved impractica- 

 ble on account of the hydrosOopicity of the compound. 

 Two experiments on the oxidation of the protoxide, under- 

 taken as a check on the other method, gave 27.486 and 

 27.527 for = 8; S = 16. {Erdmann's Journ. fur Prak. 

 Chem., 72, 1857, 361; Sitz.-Bericht der k. k. Akad., 1857.) 



J. Dumas : 54.96 (0 = 16). 

 Determined by the decomposition of the chloride with 

 argentic nitrate. The number is the mean of five experi- 

 ments; extreme diflference, 0.1 for = 16. 01 = 35.5; 

 Ag = 108. Dumas had previously made experiments on 

 the reduction of the hyperoxide to protoxide by hydrogen. 

 These gave the atomic weight at from 25.99 ito 26.09 for 

 O =: 8. Dumas believes that a part of the oxide was re- 

 duced to metal. The peroxide was prepared from nitrate 

 of the protoxide. {Annal. de Chim. et de Phys., (3,) 55, 1859, 

 150.) 



— Rawack : 54.02 (0 = 16). 

 Determined, in Schneider's laboratory, by- reducing a 

 known weight of red oxide to protoxide in a current of 

 dry hydrogen, and weighing the water formed. The num- 

 ber is derived from the mean of six selected experiments. 

 The extreme difference is 0.22 for ^ 16. [Poggend. Ann., 

 107, 1859, 607.) 



R. Schneider : 54,038 (O = 16). 

 The mean result of .four analyses of the oxalate by the 

 ordinary method of organic analysis. Extreme difference, 

 0.04 for O = 16. C = 12. The oxalate was prepared from 

 chemically pure sulphate by precipitation wath sodium car- 

 bonate, digestion with oxalic acid, and drying over sulphu- 

 ric acid. [Poggend. Ann., 107, 1859, 613.) 



MERCURY. 



The specific heat of mercury in the solid state, as observed 

 by Regnault, and the vapor density, as determined by Dumas, 

 correspond to an atomic weight of slightly above 200. 

 {Gmelin-Kruut, I. c; L. Meyer, I. c.) 



6 



