CHROMIUM. 43 



determination above.) Twenty experiments on quantities 

 of 32 urrammes, and less, of silver gave 100 parts Ag = 

 69.103 parts KCl ; extreme difference, 0.008. These data 

 combined with the composition of argentic chloride given 

 above, indicate for chlorine 35.460. 



(3.) The composition of argentic nitrate was determined, 

 and the difference betVeen the atomic weights of nitrogen 

 and chlorine. In two experiments silver was dissolved in 

 nitric acid, the solution evaporated to dryness, and the 

 nitrate kept melted until there was no further loss of 

 weight. The result obtained was that 100 silver = 157.484 

 nitrate; difference, 0.008. From series of experiments on 

 the relation of the chlorides of potassium, sodium, lithium 

 and silver to the nitrates, Stas found the difference between 

 a chloride and a nitrate from 26.586 to 26.591 ; mean 26.588. 

 These data show that the atomic weight of chlorine lies 

 between 35.455 and 35.460, and confirm the mean of all the 

 determinations of Penny, Marignac, and Stas, 35.457. The 

 silver for this investigation was either distilled or compared 

 with distilled silver; it was found impossible to reduce 

 the amount of silica in the alkaline salts below 0.002 of one 

 per cent., it was therefore determined and allowed for; 

 every possible method of purification by recrystallization 

 and otherwise was resorted to to ensure purity. The weigh- 

 ings are all reduced to vacuum. (Stas, Unters. ilber Chem. 

 ProporL, Leipzig, 1867.) 



CHROMIUM. 



The specific heat of chromium, as determined from that 

 of the oxide by Kopp, Regnault, and Neumann, corresponds 

 to an atomic heat of from 5.4 to 5.98, if the atomic weight 

 is taken at 52.4. [Gmelin-Kraut, I. c.) 



J. J. Berzelius : 56.29 (O = 16) ; 351.819 (O = 100). 



100 parts of plumbic nitrate, on precipitation with potas- 

 sic chromate, gave 98.772 parts plumbic chromate. The 

 value follows for Pb == 1294.498, and N = 88.518. {Poggend. 

 AnnaL, 8, 1826, 22.) 



T. Thomson : 64, {O = 16) ; 400 (0 = 100). 



8.14 grains of metallic chromium, converted into chromic 

 acid by heating with potash and nitre, gave a precipitate of 

 16.23 grains plumbic chromate. [Phil. D^ans., 117, 1827, 

 159.) 



