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ON THE DECOLORIZING PROPERTY OF CHARCOAL. 
RESEARCHES ON THE DECOLORIZING PROPERTY OF CHARCOAL 
AND SEVERAL OTHER BODIES. 
By M. E. Filhol. 
It is commonly stated that charcoal is the only simple body pos- 
sessing the property of absorbing coloring matter dissolved in a 
liquid : it further appears from the works of MM. Bussy and 
Payen, that decoloration by charcoal is a purely physical pheno- 
menon. 
Several compound bodies (alumina, sulphate of lead prepared by 
the moist way, hydrate of lead) also partake of the property of de- 
colorizing liquids ; but it is generally considered by Chemists that 
the action exercised by oxides on coloring matter in the prepara- 
tion of lacs is chemical, differing in this respect from that of char- 
coal ; nevertheless, Berzelius was of opinion that the decoloration 
effected by the oxides and metallic salts, resembled that produced 
by charcoal. 
In the paper which I now submit to the judgment of the 
Academy, my object has been to prove, 
1. That charcoal is not the only simple body possessing the pro- 
perty of decolorizing liquids : sulphur, arsenic, iron obtained by 
the reduction of the hydrated sesquioxide by hydrogen, are all pos- 
sessed of decolorizing power. 
2. That the number of compound bodies having an appreciable 
decolorizing power, are more numerous than has been thought, and 
that this power appears to depend much more on the state of di- 
vision of these bodies, than on their chemical qualities. 
3. That such bodies which easily appropriate one coloring mat- 
ter, may have but little tendency to do so with another ; thus, 
phosphate of lime from bones (artificially obtained) scarcely de- 
colorizes the sulphindigotate of soda, whilst it exercises a more 
energetic influence on tincture of litmus than does animal black. 
4. That the decoloration, in the majority of cases, is a purely 
physical phenomenon ; thus, the same coloring matter is absorbed 
by metalloids, metals, acids, bases, salts, and organic substances : 
it is easy, moreover, by employing suitable solvents to take again 
the coloring matter in an unaltered state from the body which 
had absorbed it. 
