OP ARTS AND SCIENCES. 59 



As we have already intimated, our analyses of the iodide of antimony, 

 as first crystallized from bisulphide of carbon, yielded very discordant 

 results. These we give in the table below, not, as before, in the exact 

 order in which the analyses were made, but in the order of the several 

 values, so as to exhibit the distribution of the errors. 



Analyses of Cetstallized Antimonious Iodide, Red 

 Vabiett. 

 No. % of Iodine. 



1 75.71 



2 75.76 



3 75.78 



4 75.80 



5 75.84 



6 75.85 



7 75.87 



8 75.89 



9 75.94 



Mean value 75.83 



Theory Sb = 122 75.74 



Theory Sb = 120 76.05 



The cause of this discordance we attributed, as we have intimated, 

 chiefly to the remarkable readiness with which iodide of antimony 

 undergoes oxidation in contact with the air, resulting in the forma- 

 tion of oxi-iodide of antimony and free iodine, thus : — 



2 Sbig + 0=0 = 2 SbOI + 2 1-I. 



While the free iodine escapes, the oxi-iodide remains as an impurity 

 in the preparation, and the effect is a replacement of a portion of its 

 iodine by oxygen. Now, since eight parts of oxygen rej^lace one hun- 

 dred and twenty-seven parts of iodine, it can readily be seen that an 

 otherwise almost imperceptible amount of oxidation would be sufficient 



we employed. For the reasons stated the results of the analyses of the prep- 

 arations we made m this way were not as concordant as those exhibited on page 54, 

 although the close agreement of the mean result with that above given was very 

 striking, and in one analysis, using three and one-half grammes of carefully 

 selected material, we obtained 66.662% Bromine. 



