RESEARCHES ON POPULINE. 
239 
I do not doubt but that these practical data may become the sub- 
ject of applications useful to analytical chemistry and industry. 
The following results, which I have extracted from my memoir, 
will give some idea of the energy with which certain decolorizing 
matters act. 
My observations have been made by the aid of one of Collar- 
deau's double lunette colorimeters. 
The Decolorizing Power of different Substances, compared to that of Purified 
Animal Charcoal, reckoned as equalto 100. 
Litmus dye. Sulphindigotate of Soda. 
Charcoal 
300. 
100. 
Pure hydrate of iron 
128.90 . 
1.97 
Alumina 
116. 
9.91 
Phosphate of lime . 
109. 
1.97 
Iron reduced by hydrogen 
95.33 . 
100. 
Milk of sulphur 
26.67 . 
0. 
Bin oxide of manganese (natural) 88.90 . 
13.80 
Indigo 
80. 
13.50 
Oxide of zinc 
80. 
6.55 
Stannic acid . 
70.40 . 
0. 
Antimonic acid 
66.66 . 
1.97 
Chromate of lead . 
70.40 . 
2.92 
Litharge 
66.66 . 
3.85 
Sulphate of antimony (natural) 
59.25 . 
0. 
Sulphate of lead 
50. 
13.80 
Binoxide of copper 
26.67 . 
0. 
Protochloride of mercury 
22.22 . 
0. 
Sulphate of baryta (artificial) 
50. 
0. 
Sulphate of lead (artificial) 
130. 
16.67 
Pharm, Jour. April 1, 1852, from Comptes Rendus. 
RESEARCHES ON POPULINE. 
By M. Piria, in a letter to M. Dumas. 
You are aware that in 1830 M. Braconnot announced the dis- 
covery of a crystalline substance, which he had succeeded in ex- 
tracting from the leaves and bark of the aspen (Populus tremula, 
and which he called populine. A recent investigation of this sub- 
stance has led me to the following results : — 
After having unsuccessfully attempted to resolve populine by 
means of synaptase, I had recourse to other agents; and the reac- 
tions which I have observed have led me to regard this substance 
as a complex group, resulting from the union of benzoic acid? 
