108 SMITHSONIAN MISCELLANEOUS COLLECTIONS VOL. 54 



In the last combination tlie single experiment by Berzelius is given 

 equal weight with Maumene's series. Both general means differ from 

 Eichards and Staehler's averages by less than one part in 10,500, or 

 0.01 per cent. 



POTASSIUM BROMIDE AND IODIDE RATIOS. 



The ratio between silver and potassium bromide was first accurately 

 determined by Marignac." I give, with his weighings, the quantity of 

 KBr proportional to 100 parts of Ag : 



Aa. KBr. Ratio. 



Mean, 110.313. ± .005 



Corrected to a vacuum this becomes 110. 343, ±.005. 



Stas," working in essentially the same manner as when he compared 

 potassium chloride and silver, and with bromide from several distinct 

 sources, found the following values for this ratio : 



110.361 

 110.360 

 110.360 

 110.342 

 110.346 

 110.338 

 110.360 

 110.336 

 110.344 

 110.332 

 110.343 

 110.357 

 110.334 

 110.335 



Mean; 110.3463, ± .0020 



In his paper on the atomic weight of nitrogen. Dean' gives three 

 measurements of the Ag : KBr ratio, but with a bromide which was sup- 



^ Oeuvres Completes, 1, 82. Four preliminary analyses are discarded. 



^ Oeuvres Completes, 1, 747. 



3 Journ. Chem. Soc, 77, 177. VMO. 



