130 PROCEEDINGS OF THE AMERICAN ACADEMY. 



iodbenzol by hydrogen. The residue which did not sublime was a 

 brownish yellow powder, containing many black specks. It did not 

 melt at 300°, but melted with blackening when held over the free 

 flame. It was not completely soluble in any of the common solvents, 

 and all our efforts to obtain from it a body fit for analysis have proved 

 fruitless. 



The experiment was next repeated under the same conditions, ex- 

 cept that the mixture w^as not heated, but allowed to stand three days 

 at the ordinary temperature. At the end of this time it had turned 

 dark brown, in fact a pale brown color appeared almost as soon as 

 the materials were mixed ; the solvents were then allowed to evapo- 

 rate spontaneously, and the residue treated with water as in the pre- 

 vious experiment, when the aqueous filtrate gave a strong test with 

 starch j^aste and chlorine water for iodine. The residue insoluble in 

 water was sublimed at a very gentle heat, and crystals of symmet- 

 rical tribrombenzol were obtained recognized by their melting point, 

 119°-120°. The residue, which did not sublime at this gentle heat, 

 was crystalline and of a reddish white color, very different from the 

 amorphous brown pi'oduct obtained under the same conditions from 

 the action of hot sodic ethylate. This crystalline residue after three 

 recrystallizations from a mixture of benzol and alcohol showed the 

 melting point 104°, and was therefore unaltered tribromiodbenzol. It 

 seems, therefore, that cold sodic ethylate behaves like hot, but the action 

 is less complete. An alcoholic solution of sodic hydrate, after being 

 warmed for ten minutes with a solution of tribromiodbenzol in benzol, 

 converted it into tribrombenzol with elimination of iodine. This, 

 therefore, acted in the same way as the hot solution of sodic ethylate, 

 but the yield seemed to be larger, and the residue from the sublima- 

 tion was lighter in color (yellow) and free from black specks. It did 

 not, however, prove to be more manageable than that previously 

 obtained. These differences may be due to the shorter heating, ten 

 minutes in this case instead of one hour when the ethylate was used. 

 Several attempts were made to detect the aldehyd, which it seemed 

 probable was formed as the secondary product in the replacement of 

 the iodine by hydrogen, but these led to no definite result. 



Sodic methjlate when boiled with a benzol solution of tribromiod- 

 benzol for over an hour gives a result similar to that obtained from 

 cold sodic ethylate ; that is, tribrombenzol was formed, but there was 

 a large amount of undecomposed tribromiodbenzol. The two sub- 

 stances were separated by careful sublimation, and recognized by their 

 melting points. Cold sodic methylate, on the other hand, gave no 



