Chemistry. 417 
trum, as measured by the difference 4 — a, increases with the pon of 
the acid in the series, excepting in the case ‘of formic acid. The author 
promises a further discussi sion of the results of his measurements, as well 
as an examination of the indices of the homalogenn aleohols C, Honea 
+0,.—Pogg. Ann., exviii, 353. 
II, CHEMISTRY. 
On the coloring matters derived from aniline—Dr. Hormann has 
bahlighea an elegant investigation of the colors derived bias anilin, 
which places the chemical nature of these substances in a clear point of 
view, Hofmann finds that the red coloring matter, produced by the 
action of the chlorids of carbon, tin, mercury, and other metals, and of 
certain oxydizing agents upon anilin, is an organic base which hes the 
formula This base he terms Rosanilin; in a pure state it 
is a perfectly colorless crystalline body, rinaced solable $ in water, and be- 
coming red on exposure to the air. It dissolves in alcoho with a dark 
red color. The change of color is at accompanied by a change of 
weight. On distillation, the base yields anilin and a carbonaceous mass, 
The sprig is GC, oH, gN,,2HO. The base is triacid, but forms three 
f 
C,,H, N,-HCl 
% 
The salts with one equivalent of acid are very stable; they exhibit for 
the most part a green metallic lustre like the wings of eantharides. The ey 
are red by transmitted light, and their solutions have a magnificent red 
color. The salts with three equivalents of acids are yellowish-brown, 
ony the mass and in sol ution. The chlorids C,H, oN. Hcl and 
40 3H 
lized salts; the triacid chlorid (oer moh on heating to 100° C., an 
comes indigo-blue, which Hofmann attributes to the Kodi ah of an un- 
stable intermediate chlorid. The author describes several crystallized 
salts of rosanilin; the acetate C,,H,,N,.C,H,O, is the most beauti- 
ful. The action of nascent cs n converts apices into somal 
is 0, = N,, awd it yields two tien of wall erystallized catia wi 
monacid aud biacid. ‘The most remarkable property of this base is the 
ation of a nitrate so insoluble that chrysanilin is the best known 
Teagent for nitric acid. One gramme of nitrate of potash in one litre 
Water imm: immediately gives a crystalline precipitate with a solution of chrys: 
