4.60 Royal Society :— 
(C.[H, (NO,)])" } 
N.. 
Nitrophenylenediamine Ss 
C.CH, (NO.)])" 
(C.{H, (N0,)}) \y, 
New acid 
H 
(C,[H, (NO,)])" 
Silver-salt NI!" Ng. 
Ag 
If the admissibility of this: interpretation be confirmed by further 
experiments, the reaction discovered by Griess furnishes a new and 
valuable method of recognizing the degree of substitution in the 
derivatives of ammonia. 
The new acid differs in many respects from the substances pro- 
duced from other nitrogenous compounds. As a class, these sub- 
stances are remarkable for the facility with which they are changed 
under the influence of acids, and more especially of bases. The new 
acid exhibits remarkable stability; it may be boiled with either 
potassa or hydrochloric acid without undergoing the slightest change. 
Even a current of nitrous acid passed into the aqueous or alcoholic 
solution is without the least effect. The latter experiment appeared 
of some interest ; for if the action of nitrous acid, im a second phase 
of the process, had assumed the form so frequently observed by Piria 
and others, it might have led to the formation of the diatomic nitro- 
phenylene-alcohol, according to the equation 
(C, [H, (NO,)])” 
H, 
H 
It deserves to be noticed that nitrophenylenediamine, although 
derived from two molecules of ammonia, is nevertheless a decidedly 
monacid base. Gottlieb’s analyses of the chloride, nitrate, and sul- 
phate left scarcely a doubt on this pomt. However, as some of the 
natural bases, quinine for instance, are capable of combining with 
either one or two molecules of acid, I thought it of sufficient interest 
to confirm Gottlieb’s observations by some additional experiments. 
The crystals deposited on cooling from a solution of nitrophenylene- 
diamine in concentrated hydrochloric acid, were washed with the 
same liquid and dried zn vacuo over lime. 
Analysis led to the formula 
L (C,[H,(NO,)])" | 
H H N, | 
(C, [H, (NO,)] x O 
N,+2H NO,=2H, 0+N,+ H, 2 
2 
2 
H, 
The dilute solution of this chloride is not precipitated by dichlo- 
ride of platinum, nor can the double salt of the two chlorides be 
obtained by evaporating the mixed solutions, which, just as Gott- 
lieb observed it, is readily decomposed with separation of metallic 
platinum. I had, however, no difficulty in preparing a platinum salt, 
