78 



SMITHSONIAN MISCELLANEOUS COLLECTIONS 



VOL. 54 



According to Eichards and Wells/ who made two very careful series 

 of syntheses, the work of Stas on the silver-chlorine ratio was subject 

 to constant errors. His silver probably contained occluded oxygen, and 

 perhaps alkalies also, and his glass vessels were attacked and changed 

 in weight by the acids used in his operations. These errors were avoided 

 by Richards and Wells, who precipitated and fused their silver chloride 

 either in porcelain or quartz vessels, generally the latter, and who em- 

 ployed silver of the highest possible purity. A number of minute cor- 

 rections were also applied to their determinations, but these cannot be 

 considered in detail now. The results obtained appear in the two fol- 

 lowing tables: 



Preliminary Series. 



Mean, 132.8668, ± .0005 



The foregoing nine series of determinations are to be classed as direct^ 

 that is, they were made for the express purpose of measuring the ratio 



' Publ. Carnegie Inst., Washington, No. 2S, 1905. 



