482 



SMITHSONIAN MISCELLANEOUS COLLECTIONS 



VOL. 54 



in the form AgCl : KoPtCl,., : : 100 :.i-. The three series then combine as 



follows : 



Seubert, 4AgCl 339.236, ± .2840 



Archibald. 4AgCl 339.180, ± .0076 



Archibald, 2AgCl 339.212, ± .0068 



General mean 339.204, ± .0051 



Archibald's two series of measurements of the ratios between silver 

 and the platinchloride can also be reduced to the form Ag:KoPtCl6:: 

 100 : X, and combined : 



4Ag series 4.50.64, ± .0120 



2Ag series 450.66, ± .0094 



General mean 450.654, ± .0074 



Archibald's data for ammonium ])latinchloride are rather simpler than 

 with the potassium salt^ since the total chlorine was determined at once, 

 instead of in two portions. His weights are subjoined : 



The derived ratios are as follows 



Per- cent. Pt. 

 43.964 

 43.954 

 43.964 

 43.969 

 43.955 



GAgCl-.Pt. GAgCl:Am,PtCh. 6Ag:Pt. 6Ag:Am,PtCh.. 



22.695 51.621 30.165 68.613 



22.699 51.643 30.147 68.588 



22.703 51.640 30.165 68.613 



22.698 51.623 30.167 68.611 



22.699 51.641 30.152 68.597 



Mean, 43.961, 22.699, 51.634, 30.159, 68.604, 



± .0061 ± .0031 ± .0032 ± .0027 ± .0034 



Pt = 195.20 195.22 195.24 195.21 195.23 



Two of the ratios can be combined with earlier measurements, as 

 follows : 



Percentage Pt in Am.PtCl^. 



Seubert 43.953, ± .0078 



Halberstadt 43.943, ± .0054 



Archibald 43.961, ± .0061 



General mean 43.951, ± .0036 



