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SMITHSONIAN MISCELLANEOUS COLLECTIONS 



VOL. 54 



Series 4 and 5, with silver arsenate of different origin from that pre- 

 viously used, gave the subjoined figures. Only the last experiment was 

 conducted by the precipitation method : 



Ag^sO,. AfjCl. Ratio. 



4.67268 4.34389 92.9636 



7.71882 7.17597 92.9672 



5.28049 . 4.90908 92.9664 



4.25346 3.95424 92.9652 



3.47340 3.22893 92.9616 



5.17269 4.80879 92.9650 



4.10766 3.81858 92.9624 



5.47133 5.08643 92.9646 



Mean, 92.9681, ± .00044 

 Hence As = 74.901. 

 These series combine with Ebaugh's thus: 



Ebaugh 92.944, ± .0025 



Baxter and Coffin, 1 92.9550, ± .00036 



Baxter and Coffin, 2 92.9681, ± .00044 



General mean 92.9614, ± .00028 



Baxter and Coffin also determined the ratio between silver arsenate 

 and silver bromide by the solution and precipitation method. Here 

 again two series of analyses are given, numbered 3 and 6, representing 

 different preparations of the arsenate. The two series are as follows : 



Ag.,AsO^. 

 8.75751 

 6.76988 

 5.19424 

 5.33914 

 8.24054 

 7.57962 

 6.05230 



Series 3. 

 AgBr. 



10.66553 

 8.24545 

 6.32590 

 6.50258 



10.03552 

 9.23147 

 7.37106 



Ratio. 

 121.787 

 121.796 

 121.787 

 121.791 

 121.782 

 121.793 

 121.789 



Mean, 121.7991, ± .00015 



