132 SMITHSONIAN MISCELLANEOUS COLLECTIONS VOL. 54 



773 grm. S. Ratio, 114.889 



114.882 

 114.88G 

 114.892 

 114.891 



Mean, 114.888, ± .0012 



1.1357 grm. AgnS. lost .1465 S. Ratio, 114.810 



1.2936 " .1670 " " 114.823 



Mean, 114.8165, ± .0044 



'Novr, combining all four series, we liave- 



Dumas 114.8234, d= .0029 



Stas 114.8522, ± .0007 



Cooke's 2d 114.888, ± .0012 



Cooke's 3d 114.8165, ± .0044 



General mean 114.8581, ± .0006 



The percentage of silver in silver sulphate has been determined by 

 Struve and by Stas. Struve ^ reduced the sulphate by heating in a cur- 

 rent of hydrogen, and obtained these results : 



Ag^SOi. Ag. Per cent. Ag. 



5.1860 3.5910 69.244 



6.0543 4.1922 69.243 



8.6465 5.9858 69.228 



^ 11.6460 8.0608 69.215 



9.1090 6.3045 69.212 



9.0669 6.2778 69.239 



Mean. 69.230, ± .004 



Stas/ working by essentially the same method obtained the following 

 figures, which imply vacuum weights : 



Ag^^Oi. Ag. Per cent. Ag. 



72.137 49.919 69.200 



60.251 41.692 69.197 



81.023 56.071 69.204 



33.115 57.523 69.209 



55.716 38.5595 69.207 



63.922 44.2355 69.202 



Mean, 69.203, ± .0012 



Combining this mean with that of Struve, the general mean becomes 

 69.205,±.0011. 



1 Ann. Chem. Pharm., 80, 203. 1851. 

 ^ Oeuvres Completes, 1, 410. 



