248 THE ATOMIC WEIGHTS. 



The following ratios are now available for computing the atomic weight 

 of chromium : 



(i.) Percentage Cr 2 O 3 from Ag 2 CrO 4 , 22.934, .0018 

 (2.) Percentage Cr 2 O 3 from Ag 2 Cr 2 O 7 , 35.236, =b .0335 

 (3.) 2AgCl : Ag 2 CrO 4 : : loo : 115.760, rb .0069 

 (4.) 2AgCl : Ag 2 Cr 2 O 7 : : 100 : 150.816, .074 

 (5.) 4AgCl : Cr 2 O 3 : : loo : 26.620, rb .0052 

 (6.) Percentage Cr 2 O 3 in Cr 2 (SO 4 ) 3 , 38.838, =b .0087 

 (7.) Percentage Cr 2 O 3 in AmCr(SO 4 ) 2 . 12H 2 O, 16.143, .0125 

 (8.) BaSO 4 : BaCrO 4 : : 100 : 108.9815, .0369 

 / (9.) BaCrO 4 : BaCl 2 : : 100 : 81.702, .014 

 (10.) 3AgCl : CrCl 3 : : 100 : 36.842, .0031 

 (II.) 2KC1O 3 : K 2 Cr 2 O 7 : : 100 : 120.216, rb .0235 

 (12.) Percentage Cr 2 O 3 in Ag 2 CrO 4 .4NH 3 , 19.059, .0074 

 (13 ) 2AgCl : Ag 2 CrO 4 .4NH 3 : : 100 : 139.357, d= .1109 

 (14.) Percentage Cr 2 O 3 in Am 2 Cr 2 O 7 , 60.337, .0029 

 (15.) Ag 2 CrO 4 : 3! : : 100 : 114.630, .015 

 (16.) Ag 2 CrO 4 .4NH 3 : 3! : : 100 : 95.208, -O497 

 (17.) 2K 2 Cr 2 O 7 : KHI 2 O 6 : : 100 : 66.212, =b .0044 

 (18.) 2Am 2 Cr 2 O 7 : KHI 2 O 6 : : 100 : 77.268, .0041 



The antecedent values to use in the reduction are 



= 15 879, .0003 S = 31.828, rb .0015 

 Ag = 107. 108, zb .0031 N = 13.935, rb .0021 

 Cl = 35.179, rb .0048 Ba 136.392, rb .0086 



1 = 125.888, rb .0069 AgCl = 142.287, .0037 

 K = 38.817, .0051 



For the molecular weight of Cr a O s , seven values are now calculable, as 

 follows : 



From (i) ................ ...... Cr 2 O 3 151.120, .0130 



From (2) ...................... " = 151.105, rb .1636 



From (5) ...................... " = 151.507, .0299 



From (6) .................. ---- " = 151.384,^.0341 



Prom (7) ..................... " =.- 153.756, .1205 



From (12) ..................... " 151.478, .0606 



From (14) ..................... " = 151.190, .0110 



General mean ............ Cr 2 O 3 = 151.229, .0039 



For silver chromate there are two values 



From (3) .................... Ag 2 CrO 4 = 329.423, .0195 



From (15) ................... " =r 329.464, it .0467 



General mean .......... Ag 2 CrO 4 = 329.430, rb .0180 



And for the ammonio-chromate we have 



From (13) ............. Ag 2 CrO 4 .4NH 3 = 396-574, - 



From (16) ............. " = 396.673, rb .2082 



General mean Ag. 2 CrO 4 .4NH 3 = 396.647, .1738 



