334 PROCEEDINGS OP THE AMERICAN ACADEMY. 



The triiodbenzol thus obtained melted at 181°, which suggested that it 

 was identical with the substance made by Istrati and Georgescu melting 

 at 182° to 184°, and this was proved to be the case by treating it with 

 fuming nitric acid, which converted it into a triioddinitrobenzol melting 

 at 210°, whereas Istrati and Georgescu* under similar conditions ob- 

 tained from their substance a dinitro derivative melting at 210°-212°, 

 That our triiodbenzol had the symmetrical constitution (I .3.5) was 

 very probable, because the trichloraniline and the tribromaniline made 

 under similar conditions are symmetrical compounds ; but, as we felt it 

 was necessary to give an absolute proof of its structure, we treated the 

 triioddinitrobenzol with aniline, when it formed a trianilidodinitrobenzol 

 melting at 181°. The symmetrical trianilidodinitrobenzol made by Palmer 

 and one of us f from symmetrical tribromdinitrobeuzol melted at 179°; 

 in spite of the difference of two degrees in these melting points there can 

 be no doubt of the identity of the compounds, and it follows, therefore, 

 that the triiodbenzol melting at 181° has the constitution I3 1 . 3 . 5. 

 This would leave only the structure 1.2.3 for Istrati and Georgescu's 

 triiodbenzol melting at 85° ; but in view of the fact that this compound 

 was isolated from a mixture of the two triiodbenzols and two tetraiod- 

 benzols, it seems to us possible that it may be the unsymmetrical isomere 

 (1.2.4) (melting at 77°) contaminated with some of these less fusible 

 substances. We had hoped to prepare several derivatives of the triiod- 

 benzol, but were unable to do so in the time at our disposal, and, as 

 we cannot continue our work together, think it well to publish this 

 account of the results so far obtained. 



Preparation op Triiodaniline. 



The triiodaniline was prepared by the method of Michael and Norton t 

 slightly modified. Ten grams of aniline were dissolved in dilute hydro- 

 chloric acid, and diluted with water at 15° or a higher temperature to 

 the volume of seven litres. This solution was then treated with a rapid 

 stream of air charged with the vapor of monochloride of iodine by pass- 

 ing it through a flask containing somewhat more than the required amount 

 of this substance heated to about 60° by immersion in warm water. 

 After thirty or forty minutes the action had come to an end, and the 

 liquid was filtered as quickly as possible to remove a heavy black precipi- 



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



t These Proceedings, XXIV. 111. 



I Bar. d. cliem. Ges., XI. Ill (1878). 



