OF AETS AND SCIENCES. 



57 



already been purified by crystallization, was placed in the tube within 

 the air-bath, but near the open mouth ; and, while a current of dry car- 

 bonic dioxide through the apparatus was steadily maintained,. the air- 

 bath was heated by a gas lamp to the required temperature which was 



indicated by a thermometer, as shown in our figure. Iodide of antimony 

 is sensibly volatile, even at 100'^ ; and long before it reaches its melting 

 point, 167^, the evaporation becomes very marked. As soon 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 receivers, it was easy to collect the different portions of the 

 sublimate. We 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 transparent, and of the most 

 brilliant ruby-red color ; the other in small rhombic plates, having the 

 same peculiar greenish-yellow color as the solution of the iodide already 

 mentioned. The amount of the last was always small, but it was larger 

 in proportion as the temperature was lower. This new and most in- 

 teresting product will be described in the paper just referred to. Of 

 these crystals, the most brilliant, chiefly of the red variety, were selected 

 for analysis. The iodine determinations were conducted in all respects 

 like those of chlorine and bromine. The iodide was first dissolved by 

 a very concentrated solution of tartaric acid, and then the solution was 

 diluted to the required extent. The same care was taken not to add 

 more than a very slight excess of. argentic nitrate, and the amount 

 required was accurately weighed out in each case. Each of the deter- 

 minations was made with a separate preparation 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 jaroducts of many 

 crystallizations from the crude material made as described above. 

 The results are collected in the following table : — 



