On the Action of Nitrous Acid upon Nitrophenylenediamine. 461 
crystallizing in splendid long brown-red prisms, by adding the dichlo- 
ride of platinum to the concentrated solution of the hydrochlorate. 
The platinum determination led to the formula 
fe #(@2(H, (NO,)})")° 7 
A Be NIC Pele 
H, val 
These experiments prove that, even under the most favourable cir- 
cumstances, nitrophenylenediamine combines only with 1 equiv. of 
acid, while the ethylene-derivatives are decidedly diacid. The dimi- 
nution of saturating power in nitrophenylenediamine, at the first 
glance, seems somewhat anomalous, but the anomaly disappears if 
the constitution of the body be more accurately examined. It can- 
not be doubted that the diminution of the saturating power is due to 
the substitution which has taken place in the radical of the diamine. 
I have pointed out at an earlier period*, that the basic character of 
phenylamine is considerably modified by successive changes intro- 
duced into the phenyl-radical by substitution. Chlorphenylamine, 
though less basic than the normal compound, still forms well-defined 
salts with the acids; the salts of dichlorphenylamine, on the other 
hand, are so feeble, that, under the influence of boiling water, they 
are split into their constituents; in trichlorphenylamine, lastly, all 
basic characters have entirely disappeared. Again, on examining the 
nitro-substitutes of phenylamine, we find that even nitrophenylamine 
is an exceedingly weak base, whilst dinitrophenylamine is perfectly 
indifferent. What wonder, then, that a molecular system, to which 
in the normal condition we attribute a diacid character, should, by 
the insertion of special radicals, be reduced to monoacidity? The 
normal phenylenediamine, which remains to be discovered, will doubt- 
less be found to be diacid, like the diamines derived from ethylene. 
Even now the group of diacid diamines is represented in the naphtyl- 
series : 
: C,, H, 
Naphtylamine H +N monoacid. 
H 
(C,, H.)" 
Naphtylenediamine 4H, N diacid. 
3 HH 
The body which I designate by the term Naphtylenediamine, is the 
base which Zinin obtained by the final action of sulphide of ammo- 
nium upon dinitronaphtaline. This substance, originally designated 
seminaphtalidam, and subsequently described as naphtalidine, com- 
bines, according to Zinin’s experiments, with 2 equivalents of hydro- 
chloric acid +. . 
“Qn the Formula investigated by Dr. Brinkley for the general 
Term in the Development of Lagrange’s Expression for the Summa- 
tion of Series and for Successive Integration.” By Sir J. F. W. 
Herschel, Bart., F.R.S. &c. 
* Mem. of Chem. Soc. vol. ii. p. 298. 
+ Liebig’s Annalen, vol. lxxxv. p. 328. 
