126 



THE ATOMIC WEIGHTS. 



52.948 

 53-150 



Mean, 53.049, ± .068 



This figure, reduced to the standard of Berlin's work on 

 the monochromate, becomes 26.525, d= .034. Berlin's mean 

 was 26.682, ± .0076. The two means, combined, give a gen- 

 eral mean of 26.676, =b .074. 



We may now consider the ratios before us, which are as 

 follows : 



(2. 



(3. 

 (4. 

 (5. 

 (6. 



(7- 

 (8. 



(9- 



(10. 



(II. 



Percentage Cr^Oa from Ag2CrO^, 23.014, ± .oil 



Percentage Cr-^g from AgjCr.p,, 35.236, ±: .0335 



AgCl : AgjCrO^ : : 100 : 1 1 5.956, dr .023 



AgCl : Ag^Cr^O, : : lOO : 150.816, ± .074 



AgCl : Cr^Oj : : loo : 26.676, ± .0074 



Percentage CrjOg in chromic sulphate, 39.1946, ± .0280 



Percentage Cr203 in ammonia chrome alum, 16.143, i .0125 



BaSO^ : BaCrO^ : : 100 : 108.9815, ± .0369 



BaCrO^ : BaClj : : lOO : 81.702, d= .014 



Molecular weight of KjCr^O,, 294.013, zb .0697 



AgCl : CrClg : : lOO : 36.842, =b .0031 



From these ratios we can at once deduce five values for 



the molecular weight of Cr^Oa, as follows : 



From (I) Cr^O; 



" (2) " ' 



« (5) " 



« (6) " 



" (7) " 



General mean.. 



152.855, ± .034 



For barium chromate we get two values 



From (8) BaCrO^ 



" (9) " 



General mean 



253.494, i .094 

 = 253.976, =t .067 



= 253.816, zfc .054 



From (3) we get Ag^CrO^ = 331.739, ± -070 

 " (4) " Ag.^Cr207 = 431.470, ± .215 

 " (II) " CrC]3= 158.102, ± .018 



Finally, from these intermediate data we derive six values 

 for the atomic weight of chromium : 



