338 PROCEEDINGS OF THE AMERICAN ACADEMY. 



did not have time to try whether the mouoiiitro compound could be 

 obtained with a still more dilute nitric acid. 



The agreement between the melting points of our triiodbenzol, 181°, 

 and triioddinitrobeuzol, 210°, with those obtained by Istrati and 

 Georgescu, * 182°-184° and 210°-212°, establishes the identity of these 

 substances beyond a doubt. The triioddinitrobeuzol also gives us the means 

 of proving their constitution. For this purpose 0.5 gram of the triioddi- 

 nitrobenzol were heated with 0.5 gram of aniline ; this proportion gives 

 about six molecules of aniline to each molecule of the dinitro compound. 

 The heating was carried on for two hours on the steam bath, and the 

 product, a dark red solution, was freed from the excess of aniline by 

 washing with dilute hydrochloric acid, when it formed a dark red sticky 

 mass, which was purified by working it well with a rod under dilute 

 hydrochloric acid and then crystallizing it from alcohol. It showed the 

 constant melting point 181°, which agrees sufficiently well with 179°, 

 that given by Palmer and one of usf for the trianilidodinitrobenzol 

 made from the tribromdiuitrobenzol Brg 1.3.5, (N02)2 ^ • '^- This 

 proves, therefore, that the triiodbenzol melting at 181° has the iodine in 

 the position 1.3.5, as would have been inferred from its preparation 

 from triiodaniline, which according to the analogy of the chlorine and 

 bromine compounds should have the symmetrical constitution. 



* Bui. Soc. Sci. Fiz., I. 62, 66. 

 t These Proceedings, XXIV. 111. 



