458 Royal Society :— 
siderable quantity of this substance, which is not quite easily pro- 
cured. 
I have made a few experiments with this compound in the hope of 
obtaining some insight into its molecular constitution. If, bearing 
in mind the numerous analogies between the radicals ethyle and 
phenyle, we assume that the latter, by the loss of hydrogen, may be 
converted into a diatomic molecule, phenylene C, H,, corresponding 
to ethylene, the existence of a group of bases corresponding to the 
ethylene-bases cannot be doubted. 
C,H, (C, Hy)” 
Ethylamine H }N*. Ethylenediamine UH, N,. 
H H, 
C,H, (, H,)" 
Phenylamine H fx. Phenylenediamine H, Ly, 
H H, 
With the last-named body agrees in composition the compound 
known as semibenzidam, or azophenylamine, which Zinin obtained 
by exhausting the action of sulphide of ammonium on dinitro- 
benzole. 
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. 
C, H, i 
Phenylamine Tae Ns 
H 
(C, Hy)" 
Phenylenediamine H, pe 
(C,[H, (NO.)})" 
Nitrophenylenediamine H, } N,. 
H 
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 
* H=1; 0=16; C=12, &. 
