JACKSON AND CALVERT. METAPHENYLENE DIAMINE. 153 



hydrochloric acid upon the free base, while, although the tribrom base 

 dissolves in strong hydrochloric acid, we have not succeeded in obtain- 

 ing the solid chloride from this solution. It must not be inferred from 

 this comparison, however, that the chloride of dibromphenylene dia- 

 mine is especially stable, for this is not the case, since it loses nearly 

 4 per cent of its weight by standing in a desiccator, and is also 

 decomposed by water. 



Bromide of Dibromphenylene Diamine, C(.H2Br2NH3BrNH2. — 

 This substance was made by adding dibromphenylene diamine to dis- 

 tilled hydrobromic acid (boiling point 123°) until it ceased to dissolve 

 easily in the cold. A good deal of trouble was encountered in obtain- 

 ing the solid salt from this solution, as heating decomposed it, and none 

 of the organic solvents miscible with water gave a precipitate with it ; 

 spontaneous evaporation indeed gave the salt, but as we did not know 

 its properties at the time of the preparation we were afraid of decom- 

 position during such long standing, and accordingly proceeded as fol- 

 lows : The aqueous solution was covered with a rather thick layer of 

 ether, and the whole stirred vigorously for about a quarter of an hour ; 

 under this treatment the bromide crystallized out in the lower part of 

 the ether, when it was separated, washed with ether, and dried in a 

 desiccator over sulphuric acid. It then gave the following results on 

 analysis : — 



I. 0.4433 gram of the substance gave by the method of Carius 

 0.7191 gram of argentic bromide. 

 11. 0.3014 gram of the substance gave 0.4884 gram of argentic 

 bromide. 



Calculated for Found. 



Cr.HoBroNIIjBrNHj I. II. 



Bromine 69.16 69.04 68.96 



The sample used in the first analysis had been dried for only three 

 hours, that for the second had stood in a desiccator over sulphuric 

 acid for three days, showing that the salt is stable under these circum- 

 stances. The bromide is therefore more stable than the chloride, as 

 that lost nearly four per cent of its weight in a desiccator, which 

 amounts to one third of the acid that it contains. 



The bromide of dibromphenylene diamine forms white needles, 

 which turn brown quickly, when exposed to the air. It is decomposed 

 by water, but is soluble in ethyl, or methyl alcohol, the solution 

 apparently decomposing on standing ; insoluble in ether, benzol, oi 

 ligroine. 



