384 Dr. Mahla on Gallic and Gallhumic Acid. 
precipitated, was easily redissolved by free muriatic acid. Such 
a solution, containing but little free muriatic acid, produced 
black insoluble precipitates with limewater, with the different 
salts of lime and baryta, with sulphate of zinc and sulphate of 
copper. Another portion of the filtered liquor super-saturated 
with acetic acid, caused precipitates of a black color in solutions 
of acetate of lead and nitrate of silver. From the silver pre- 
cipitate, metallic silver was soon separated. 
The lead precipitate was carefully washed with distilled water, 
and after being dried in an air-bath at a temperature not ex- 
ceeding 200° F. (94° C.) for ten hours, it was heated over a spirit 
lamp, until the organic matter was perfectly destroyed. The 
residue, consisting of a mixture of oxyd of lead and metallic 
lead, was treated with acetic acid, and from it the whole quan- 
tity of oxyd of lead was calculated. ) 
1-052 gram. gave 0°662 of the mixture of PbO+Pb, which 
left after being treated with acetic acid 0-037 metallic lead, a 
uantity corresponding to 0-041 oxyd of lead. The acetic acid 
extracted 0625 oxyd of lead, which quantity added to the above 
found 0-041 gives 0°666. This is equal to 63°30 per cent. 
Gallhumic (metagallic) acid, which was detected by Pelouze in 
the residue of distillation, when gallic acid was suddenly heated 
to 480° F. (249° C.) shows the same reactions, and its lead salt, 
2PbO, C'*H20%, contains 63-04 per cent of the oxyd of lead. 
No doubt can therefore exist about the identity of Pelouze’s acid 
and my product. Two equivalents of gallic acid are divide 
exactly into one equiv. of gallhumic, two equiv. of carbonic acid, 
and three equiv. of water: 
C1 2H3203 
2 4 
cvtore= — 
GraHsore 
C into gall 
stances on gallic acid and the formation of the new product, 1s 
explained by eee acid to be only an intermediate 
product, the final res t being carbonic acid and water. 
fe ee 
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