112 J. P. Cooke—Atomic Weight of Antimony. 
it reaches its melting point, 167°, the evaporation becomes very 
marked. Assoon as melted, it sublimes quite rapidly ; and we 
obtained the best results by ‘keeping the temperature between 
180° and 200°, and by shifting the adapters we used as receiv- 
ers, it was —_ to collect the different portions of the subli- 
te. thus obtained crystals of two isomeric modifications 
of iodide of antimony : the more abundant in large hexagonal 
plates, often half an inch or more in diameter, perfectly trans- 
parent, and of the most brilliant ruby-red color ; the other in 
small — — ee the same peculiar greenish: yellow 
color as the solution of the iodide already mentioned. The 
Ganaat of the bee was always small, but it was ae in pro- 
portion as the temperature was lower. This new and most 
interesting product will be described in the paper just referred 
to. Of these crystals, the most brilliant, chiefly of the red va- 
riety, were selected for analysis. The iodine determinations 
were conducted in all respects like those of chlorine and bro- 
mine. The iodide was first dissolved by a very concentrated 
solution of tartarie acid, and then the solution was diluted to 
the required extent. The same care was taken not to add 
tion in so far as it was a product of a separate sublimation ; 
but the material sublimed was essentially the same in all cases, 
—a mixture of the products of many crystallizations from the 
crude material made as described above. The results are col- 
lected in the following table : 
ANALysis oF IopipEe or ANTIMONY. 
IopINE —e. 
No, Wt ofSbl,, Wt. of Agl, nigew roves Variety. 
i 171877 16727 76°110 Pure red. 
2. 0°4610 0°6497 767161 tesa yellow. 
3. 3°2527 45716 75°956 Pur re 
4, 1°8068 2°5389 75°939 ure 
5. 15970 2°2456 75°990 Red ind 1 yellow. 
6. 2°3201 3°2645 76°C40 Pure re 
‘* 0°3496 0°4927 76°161 Chiefly anew 
Mean -wAlRes kines ca bocdiociwniness 76°051 
Theory Sb==120, requires a inne 76°047 
Theory Sih 82,.. <5 oi eerie nate ne: 75°744 
If in calculating the results of these iodine determinations we 
use the atomic — of Stas, I=126°85 and Ag=107'93, the 
mean value would be 76-034, and the corresponding atomic 
weight of antimony 119-95. 
