152 PROCEEDINGS OF THE AMERICAN ACADEMY. 



tinum under the conditions already described when speaking of the 

 tribromphenylene diamine. The action in this case was very slow ; 

 whereas the tribrom compound dissolved after treatment for a short 

 time, it was necessary to carry on the action for over twelve hours in 

 order to bring the dibromamine into solution. The product yielded 

 an oily free base, smelling like metaphenylene diamine, which, how- 

 ever, we did not succeed in obtaining in a solid state. It gave an 

 easily soluble chloride, so there can be no doubt that bromine was 

 removed. We are unable to determine with certainty the cause of the 

 very slow removal of the bromine from the dibromphenylene diamine ; 

 it is possible that it is only mechanical, as it was observed that this 

 substance showed a tendency to form a coating on the surface of the 

 tin, or on the other hand it may be that the symmetrical position of 

 the three atoms of bromine in the tribromphenylene diamine has the 

 effect of loosening their attraction for the benzol ring. This latter 

 explanation seems to us the more probable. 



Chloride of Dibromphenylene Diamine, CsHgBrgNHsClNHo. This 

 salt can be made by dissolving the diamine in strong aqueous hydro- 

 chloric acid and allowing the solution to evaporate spontaneously, but 

 we did not use this method in preparing the salt for analysis, because 

 we feared that it might undergo a partial decomposition, if deposited 

 from a solution containing water. We therefore prepared it by pass- 

 ing hydrochloric acid gas through a solution of the diamine in benzol, 

 until the liquid fumed strongly, and no more solid matter was depos- 

 ited. The precipitate thus obtained was pressed repeatedly between 

 filter paper, and dried for one hour over sulphuric acid, when it gave 

 the following result on analysis : — 



0.2173 gram of the salt gave by the method of Carius 0.3713 gram of 

 the mixture of argentic chloride and bromide. 



Calculated for Found. 



CgHjEroNHaClNHj 



Chlorine and Bromine 64.63 64.28 



The chloride of dibromphenylene diamine is much more stable than 

 the corresponding tribrom-compound, since, whereas the chloride of 

 tribromphenylene diamine lost all its hydrochloric acid when heated 

 to 100° for a short time, the chloride of dibromphenylene diamine 

 showed a loss under the same conditions of only 5 per cent instead of 

 the 12.07 per cent, which represents the loss, if the whole of its 

 hydrochloric acid had been given up. Further the salt of the dibrom 

 compound can be made by the action of a strong aqueous solution of 



