145 
substance. It crystallises in yellow needles, which are 
almost insoluble in the usual menstrua, such as alcohol, 
benzol, and glacial acetic acid. 
JSFitroanthraflavic Acid, a body already referred to in 
the paper of 1871, is prepared by dissolving anthraflavine 
in fuming nitric acid and after allowing to stand some time, 
adding water, which precipita;tes the nitro-acid as a light 
yellow crystalline powder. It is obtained on spontaneous 
evaporation of its alcoholic solution in large well-defined 
rhombic crystals of a deep yellow colour, the composition of 
which is expressed by the formula Ci4H4(N 02)^04. Most of 
the salts, such as the potassium, sodium, magnesium? 
barium, silver, and mercury salts, are soluble in boiling 
water, and crystallise in lustrous needles, varying in colour 
from light-yellow to brownish-red. By reduction with tin 
and hydrochloric acid the nitro-acid yields a dark-blue 
powder, which is almost insoluble in alcohol, glacial acetic 
acid, &c., but dissolves in caustic alkalies with a fine violet 
colour like that of alkaline solutions of alizarine, 
Diacetylanthraflavine has already been described by 
Perkin.'^ We found its melting point to be at 227°C. 
Diethylanthrajiavine, Ci4H6(C 115)204 was prepared by 
heating a mixture of anthraflavine, caustic soda, iodide of 
ethyl, and a little alcohol in sealed tubes to 120°, and crys- 
tallising the product from boiling alcohol. It crystallises in 
light yellow needles, which are soluble in benzol and glacial 
acetic acid, but insoluble in water. It fuses at 232°. The 
fused substance on cooling is converted into a mass of pris- 
matic crystals. The spectrum of the solution in concentrated 
sulphuric acid, which is red, shows a well-defined absorption 
band between the green and blue. 
Dimethylanthmflavine, the preparation of which is 
similar to that of the preceding, has almost the same pro- 
perties as the ethyl compound. It fuses at 247"'-248°. 
* .Journal Chem. Soc. XXVI., p. 20. 
