ATOMIC WEIGHTS 



109 



posed to be not quite pure. His results, however, are so close to later 

 determinations that they are worth citina;: 



Mean, 110.313, ± .0010 



The recent measurements of this ratio by Richards and Mueller ' differ 

 considerably from the concordant results of Stas and Marignac. The 

 modern work was probably based upon purer materials, especially in the 

 case of the silver employed. For details upon this side of the discussion 

 the original memoirs must be consulted. The figures, with vacuum 

 weights, given by Eichards and Mueller, are as follows: 



Mean, 110.319, ± .0004 



This combines with the former determinations thus : 



Marignac 110.343, ± .0050 



Stas 110.3463, ± .0020 



Dean 110.313, ± .0010 



Richards and Mueller 110.3190, ± .0004 



General mean 110.3193, ± .00033 



Richards and Mueller also determined the second ratio, AgBr : KBr 

 100 : X. Their figures are — 



KBr. AgBr. Ratio. 



2.19027 3.45617 63.3728 



4.19705 6.62285 63.3723 



2.06723 3.26206 63.3719 



2.58494 4.07889 63.3736 



Mean, 63.3727, ± .0003 



1 Publ. Carnegie Inst., Washington, No. 69, p. 27. 1907. 



