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SMITHSONIAN MISCELLANEOUS COLLECTIONS 



VOL. 54 



Turner ' made live experiments, with the following results ; 



72.754 

 72.406 

 72.G22 

 72.664 

 72.653 



Mean, 72.680, ± .0154 



Hence Ba= 137.439. 



Of these, Turner regards the fourth and fifth as the best; but for 

 present purposes it is not desirable to so discriminate. 



Richards' determinations ^ fall into three series, and all are character- 

 ized by their taking into account chloride of silver recovered from the 

 wash waters. In the first series the barium chloride was ignited at low 

 redness in air or nitrogen; in the second series it was fused in a stream 

 of pure hydrochloric acid; and in the third series it was not ignited at 

 all. In the last series it was weighed in the crystallized state, and the 

 amount of anhydrous chloride was computed from the data so obtained. 

 The data, corrected to vacuum standards, are as follows : 



Mean, 72.653, ± .0014 



Hence Ba = 137.362. 



If we combine this with Eichards' silver series, which, in mean, may 

 be written 2Ag: BaCls :: 100 : 96.525, the cross ratio between silver and 

 chlorine becomes Ag: CI: : 100 : 32.858. 



Thorpe's ^ measurements of this ratio are not important, for they 

 were merely intended as a check iipon the method he used in determining | 

 the atomic weight of radium, which involved the manipulation of very 

 small quantities of material. His data are given here for the sake of, 

 completeness : 



1 Phil. Trans., 1829, 291. 



= Proc. Amer. Acad., 29, 65, 1S93. 



'■^ Proc. Roy. See, 80A, 298. 1908. 



