NICKEL AND COBALT. ' 309 



The second of these ratios was also studied by Winkler, and the two 

 series combine as follows : 



Winkler 20.864, zb .0050 



Hempel and Thiele 20.556, ± .0043 



General mean 20.'687, ± .0033 



Hempel and Thiele api)ly to it a correction for silver chloride retained 

 in solution, but its amount is small and not altogether certain. For 

 present purposes the correction may be neglected. 



For the atomic weight of nickel we now have ratios as follows : 



(I.) Per cent, of Ni in NiCoO^.sH.^O, 29.084, ± .006 

 (2.) Per cent, of CO2 from NiC20^.2H20, 44.098, ± .027 

 (3.) Per cent, of Ni in NiCjO^.aH.^O, 31.408, ± .0026 

 (4.) Per cent, of COj from NiC204.2H20, 47.605, ± .053 

 (5.) Per cent, of Ni in brucia nickelocyanide, 5.7295, zb .0034 

 (6.) Per cent, of Ni in strychnia nickelocyanide, 6.595, ± .005 

 (7.) Per cent, of NiO in NiSO^, 48.269, d= .oiS 

 (8.) Per cent, of Ni in NiO, 78.570, zh .0006 

 (9-) Ag2 : NiCl.3 : : 100 : 60.194, rb .0061 



(10.) 2AgCl : Ni : : 100 : 20.590, =h .0049 



(11.) Ag2 : Ni : : 100 : 27.359, d= .0059 



(12.) AUj : Nij : : 100 : 45.209, ± .019 



(13.) BaSO^ : K2Ni(SOj2-6H20 : : 100 : 93.6505, zb .001 



(14.) Ni : H2 : : lOO : 3.4211, ± .001 



(15.) I2 : Ni : : loo : 23.255, zb .0091 



To the reduction of these ratios the following atomic and molecular 

 weights are applicable : 



O = 15.879, zb .0003 I = 125.888, zb .0069 



C = 11.920, zb .0004 K = 38.817, zb .0051 



N = 13.935, zb .0021 Ba =r 136.392, zb .0086 



S = 31.828, lb .0035 All = 195.743, ± .0049 



Ag =r 107. 108, zb .0031 AgCl = 142.287, zb .0037 

 CI = 35. 179, zb .0048 



Since the proportion of water in the oxalates is not an absolutely cer- 

 tain quantity, the data concerning them can be l)est handled by employ- 

 ing the ratios between carbon dioxide and the metah Accordingly, ratios 

 (1) and (2) give a single value for Ni, and ratios (3) and (4) another. In 

 all, there are thirteen values for the atomic weight in question : 



From (i) and (2) Ni = 57.614, zb .0372 



From (5) "= 57.625, dz .0343 



From (3) and (4) " = 57-635. ± .0644 



From (6) " = 57-687, ± .0439 



From (8) "= 58.218, zb .0020 



From (7) " ^ 58.268, zb .0428 



From (13) " = 58.448, zb .0206 



