304 Gallic Acid. 
25002. to 3000/., every thing worth preserving in the collection 
would be known, and the extent of the expectation that ought 
to be formed be fully ascertained.—At all events, an acquaint- 
ance with the contents of the remaining rolls would afford much 
curious and even useful information, respecting the state of so- 
ciety, literature, science, and the arts, among the ancients; par- 
ticularly in the Greek colonies of Magna Grecia and Sicily. 
GALLIC ACID. 
M. Braconnot has published the following improved processes 
for obtaining this acid. Eight ounces of pounded gall-nuts were 
infused for four days ina little more than two pints of water, and 
agitated occasionally, at the end of which time they were thrown 
on a cloth and the residue was strongly pressed: the liquid thus 
separated was filtered, and set aside in a glass bottle covered with 
paper for two months, during which time it deposited much 
gallic acid in crystals. The mould was removed from the sur- 
face, and the fluid being then passed through a cloth subjected 
to pressure, the mass left in the cloth was found to be principally 
gallic acid. The liquid was then evaporated to the consistence 
of a syrup, and in tw enty-four hours more crystals were depo- 
sited, which were again separated by a cloth and pressure. The 
solid refuse of the first infusion, which, having been moistened, 
had been left to ferment during the two months that the infursiin 
had been set aside, also yielded, by the action of boiling water, — 
a portion of crystallized acid. The whole quantity of crystals 
obtained by these means was nearly two ounces, but mixed with 
an insoluble powder. To get rid of this they were boiled in 18 
cubic inches of water: the liquid being filtered, 1544 grains of a 
peculiar substance remained on the filter, and fawn- coloured 
crystals were deposited on cooling, which when pressed and dried 
weighed 617 grains; 1541 grains more were got by evaporating 
and crystallizing the mother liquor. 
M. Braconnot’s second process is still better. He exposed 
moistened gall-nuts for a month to a temperature of from 68° to 
77° of Fahrenheit, moistening them now and then with water. 
They swelled, became mouldy, and formed a whitish paste. A 
coloured liquid which it contained being separated by pressure, 
the mass was treated with boiling water to dissolve the acid; the 
fluid when separated by pressure and cooled gave a crystalline 
magma of gallic acid. 
To purify his gallic acid M., B. employed animal charcoal 
(common ivory black) washed in muriatic acid: 100 parts of the 
coloured acid, 800 pacts of water, and 18 parts of the charcoal 
(moistened before mixture with the acid and water) were put into 
a bottle, which was then kept for 15 minutes in boiling wo 
e 
