CARBON. 31 



extreme difference, 0.38. Three experiments on natural 

 and one on artificial graphite gave C = 75.087; extreme 

 difference, 0.13. The number is the mean of all experi- 

 ments. Erdmann and Marchand adopt 75. Calcium chlo- 

 ride was used in these experiments instead of sulphuric 

 acid to avoid objections as to the possible volatility of the 

 acid. {Erdmann's Journ. fur Frak. Chem., ^3, 1841, 159.) 



Berzelius and Liebig and Redtenbacher : 13.110 

 (0 = 16) ; 75.741 (O = 100). 



Five analyses by Berzelius of the tartrate of lead, the 

 decomposition being effected by heat, gave 62.7431 per cent. 

 plumbic oxide ; extreme difference, 0.045. Several analyses 

 of plumbic racemate gave a mean of 62.75 per cent, oxide; 

 extreme difference, 0.05. The salts were prepared by frac- 

 tional precipitation of plumbic acetate with tartaric and 

 racemic acids respectively. They were dried at 100°. {Pog- 

 gend. AnnaL, 19, 1830, 306.) From the analyses of the 

 tartrate Liebig and Redtenbacher calculate C = 75.771, and 

 from the racemate 75.711, taking Pb = 1294.489 and H = 

 6.2394. {Liebig' s AnnaL, 38, 1841, 137.) 



Liebig and Redtenbacher: 13.137 (0=16); 75.854 

 (O = 100). 



Determined by decomposing known weights of organic 

 salts of silver in a covered crucible by heat and weighing 

 the silver. Five analyses of each of the following salts 

 showed that 18.6113 Ag = 28.8098 acetate ; 9.6171 Ag = 

 16.223 tartrate; 16.2641 Ag = 27.438 racemate; 16.0596 

 Ag = 25.9019 malate. If Ag = 1351.607 and H = 6.2394, 

 the above value for C follows, with an extreme difference 

 for the 20 analyses of 0.705, (0 = 100.) The figures are all 

 calculated for vacuum. [If Ag = 107.93 and H = 1.0025, 

 the average number obtained from the mean of each set of 

 analyses gives C = 12.06865 or 75.429.] The acetate was 

 prepared by partially neutralizing pure acetic acid with 

 ammonia, precipitating with argentic nitrate and recrystal- 

 lizing the salt from hot aqueous solution. The crystals 

 were dried at 103°. The acetic acid was prepared from 

 plumbic acetate. The tartrate was prepared by adding tar- 

 trate of sodium and potassium to a hot (80° to 85°) dilute 

 solution of argentic nitrate till a small permanent precipi- 

 tate was formed, and cooling the solution. The racemate 

 was prepared from pure acid racemate of ammonium like 

 the tartrate. The malate was prepared from calcium 



