With the last-named hody agrees in composition the compound 

 known as semibenzidam, or azophenylamine, which Zinin obtained 

 by exhausting the action of sulphide of ammonium on dinitro- 

 benzol. 



Those chemists, however, who have had an opportunity of be- 

 coming acquainted with the well-defined properties of ethylenedia- 

 mine, will not be easily persuaded to consider the uncouth dinitro- 

 benzol-product sometimes appearing in brown flakes, sometimes as a 

 yellow resin, rapidly turning green in contact with the air as stand- 

 ing to smooth phenylamine in a relation similar to that which obtains 

 between ethylenediamine and ethylamine; we much more readily 

 admit a relation of this description between phenylamine and Gott- 

 lieb's crimson-coloured base, in which the clearly pronounced cha- 

 racter of the former is still distinctly visible, although of necessity 

 modified by the further substitution which has taken place in the 

 radical. 



Phenylamine 

 Phenylenediamine 



Nitrophenylenediamine 



Ce HJN. 

 H/ 



'X IN,. 



Hf " "--^i, i 

 2 J 



(C.[H,(NO,)])"1 

 H 2 ? N 2 



H J 



Does the latter formula really represent the molecular constitution 

 of the crimson needles ? The degree of substitution of this body 

 might have been determined by the frequently adopted process of 

 ethylation. But even a simpler and a shorter method appeared to 

 present itself in the beautiful mode of substituting nitrogen in the 

 place of hydrogen, lately discovered by P. Griess. The red crystals 

 undergo, indeed, the transformation, which he has already proved for 

 so many derivatives of ammonia, with the greatest facility. 



On passing a current of nitrous acid into a moderately concen- 

 trated solution of the nitrate of the base, the liquid becomes slightly 

 warm, and deposits on cooling a considerable quantity of brilliant 

 white needles, the purification of which presents no difficulty : spa- 



