348 



SMITHSONIAN MISCELLANEOUS COLLECTIONS 



VOL. 54 



tated its solution with mercurous nitrate, and ignited the precipitate, 

 with the subjoined results. Vacuum weights are given : 



General mean, 60.337, ± .0029 



From Meineke's figures Cr = 52.11. 



The chromate of silver, Ag„Cr04, and the amraonio-chromate, Ag2Cr04. 

 4^113, both prepared with all necessary precautions to insure purity, 

 were first treated essentially as in Berlin's experiments, except that the 

 traces of silver chloride held in solution by the chromic chloride were 

 thrown out by sulphuretted hydrogen, estimated, and their amount added 

 to the main portion. Thus the chief error in Berlin's work was avoided. 

 I subjoin the data obtained, with vacuum standards, as usual. All of 

 Meineke's results are so corrected : 



Hence we have the following ratios, as in the case of Berlin's data 



Mean. 22.931,±.0019 Mean, 115.737,±.0072 

 Berlin, 23.014,±.0n0 



Mean, 26.560, ±.0093 



General mean, 22.934,±:.0018 



* Calculated back from Meineke's value for Cr. to replace an evident misprint in tlic original. 



