318 SMITHSONIAN MISCELLANEOUS COLLECTIONS VOL. 54 



Mean, 13.079, ± .0096 



Hence Sb = 122.33. 



The third and fourth series of experiments were made with pure 

 antimony trichloride, SbClg, prepared by the action of mercuric chloride 

 upon metallic antimony. This preparation, in the third series, was dis- 

 solved in hydrochloric acid, and titrated. In one experiment solid 

 KoCrgO- in weighed amount was added before titration; in the other two 

 estimations KCIO3 was taken as usual. The third column gives the 

 percentages of oxygen corresponding to 100 parts of SbCl3 : 



1.8576 grm. SbCl,, needed .5967 grm. K.Cr.O^ and 33.4 cc. sol 

 1.9118 " .3019 " KCIO3 " 16.2 



4.1285 "■ .6801 •' KCIO, " 23.2 



Hence Sb = 121.24. 



The fourth set of experiments was gravimetric, 

 mixed with tartaric acid, was tirst precipitated by hydrogen sulphide, 

 in order to remove the antimony. The excess of HjS was corrected by 

 copper sulphate, and then the chlorine was estimated as silver chloride 

 in the ordinary manner. 100 parts of AgCl correspond to the amounts 

 of SbClg given in the third column : 



1.8662 grm. SbClj gave 3.483 grm. AgCl. 53.580 



Mean, 53.623, ± .015 



The volumetric series with SbClg gave Kessler values for Sb ranging 

 from 121.16 to 121.47. The gravimetric series, on the other hand, yielded 

 results from Sb = 124.12 to 124.67. This discrepancy Kessler rightly 

 attributes to the presence of oxygen in the chloride; and, ingeniously 

 correcting for this error, he deduces from both sets combined the value of 

 Sb = 122.37. 



The several mean results for antimony agree so fairly with each other, 

 and with the estimates obtained bv Dexter and Dumas, that we cannot 



