ATOMIC WEIGHTS 485 



For the ratio AgBr : Pt : : lUO : x— 



2AgBr series 103.954, ± .0054 



4AgBr series 103.956, ± .0052 



General mean 103.955. ± .0037 



For the ratio AgCl : Pt : : 100 : .r— 



2AgCl series with K.PtCU 136.208, ± .0040 



4AgCl series with K.PtCls 136.196, it .0052 



6AgCl series with Am,PtCI(i. . . 136.194, ± .0186 



General mean 136.203, ± .0031 



For the ratio Ag: Pt: : 100 : x— 



2Ag series with K,PtCl„ 180.972, ± .0052 



4Ag series with K.PtCl,, 180.960, ± .0064 



6Ag series with Am,PtCl„ 180.954, ± .0162 



6Ag series with Am.PtBr, 180.960, ± .0180 



2Ag series with K„PtBro 180.964, ± .0090 



4Ag series with K.PtBr., 180.960, ± .0112 



General mean 180.965, ± .0034 



From the last two ratios the cross ratio Ag: CI:: 100: 32. 864, ±.0039 

 is deducible, which agrees closely with the measurements by Richards 

 and Wells. From the corresponding ratios Ag : Pt and AgBr : Pt, we have 

 the ratio Ag : Br : : 100 : 74.080, ± .0070. These agreements with the best 

 determinations of the silver-halogen ratios is good evidence in favor of 

 Archibald's work. 



Rejecting the work of Berzelius and Andrews, the following ratios 

 are now available from wliich to compute the atomic weight of platinum : 



(1). Am,PtCle:Pt: :100:43.951, ± .0036 



(2). 6Ag:Am,PtCle: : 100: 68.604, ± .0034 



(3). 6AgCl:Am,PtClo:: 100: 51.636, ± .0032 



(4). K,PtCl„:Pt: : 100: 40.1484, ± .00085 



(5). Ag:K,PtCle: :100:450.654, ± .0074 



(6). AgCl:K,PtCl«: : 100: 339.204, ± .0051 



(7). Am,PtBr„:Pt: : 100: 27.443, ± .0021 



(8). 6Ag:Am,PtBr,,: : 100: 109.816, ± .0055 



(9). 6AgBr:Am,PtBr„: : 100: 63.084, ± .0018 

 (10). K„PtBr„:Pt: : 100: 25.927, ± .0014 

 (11 ) . Ag : K„PtBr„ : : 100 : 697.936, ± .0131 

 (12). AgBr : K„PtBr« :: 100: 400.932, ± .0069 

 (13). PtBr4:Pt: :100:37.847, ± .0033 

 (14). K,PtCl6:2KCl: : 100: 30.671, ± .0060 

 (15). K„PtBr„:2KBr: : 100: 31.591, ± .0068 

 ( 16 ) . 2KC1 : Pt : : 149.182 : 195.50, it .0330 

 (17). Ag:Pt::100:180.965, It .0034 

 (18). AgCl:Pt:: 100: 136.203, ±.0031 

 (19). AgBr : Pt :: 100: 103.955, ± .0037 



