soo 
G A L 
G A L 
GAL 
year, three galleons and a tender should be 
sent to-New Spain for the plate. They are 
appointed to sail from Cadiz in January, 
that they may arrive at Porto Bello about 
the middle of April; where, the fair being 
over, they may take on board the plate, and 
be at Havannah with it about the middle ot 
June; where they are joined by the flota, 
that they may return to Spain with the great- 
er safety. 
GALLERY, in fortification, a covered 
walk, across the ditch of a town, made or 
strong beams, covered over head with planks, 
and loaded with earth : sometimes it is co- 
vered with raw hides to defend it from the 
artificial fires of the besieged. See Forti- 
fication. 
Gallery of a mine, is a narrow passage, 
or branch of a mine carried on under-ground 
to a work designed to be blown up. Both 
the besiegers and the besieged also, carry on 
galleries in search of each others mines, and 
these sometimes meet and destroy each 
other. 
GallerY, in a ship, that beautiful frame, 
which is made in the form of a balcony, at 
the stern of a ship without board ; into 
which there is a passage out of the admiral’s 
or captain’s cabin, and is for the ornament 
of the ship. 
GALLEY, in naval affairs, a low-built 
vessel using both sails and oars, and common- j 
ly carrying only a main-mast and foremast, 
be struck or lowered at pleasure. 
GALL1AMBIC verse, in antient poetry 
a verse consisting of six feet, viz. an anapest 
or a spondee ; an iambus, or an anapest, or 
a tribrach ; an iambus ; a dactyl ; an ana- 
pest. 
GALLIC acid, in chemistry, is obtained 
from the nut-gall which grows on some spe- 
cies of oak. In an infusion of galls made 
with cold water, a sediment is formed which 
on examination is found to have a crystalline 
form and an acid taste. By letting an in- 
fusion of galls remain a long time-exposed 
to the air, and removing now and then the 
mouldy skin which termed on its surface, a 
large quantity of this sediment was obtained ; 
which being edulcorated with cold water, 
redissolved in hot water, filtrated and eva- 
porated very slowly, yielded an acid salt in 
crystals as line as sand. 
Mr. Davy has lately pointed out another 
method which yields gallic acid in a state of 
considerable purity. Boil for some time a 
mixture of carbona’t of barytes and infusion of 
nut-galls. A blueish green liquid is obtained, 
which consists of a solution of gallic acid and 
barytes. Filter and saturate with diluted 
sulphuric acid. Sulphat of barytes is de- 
posited in the state of an insoluble powder, 
and, a colourless solution of gallic acid remains 
behind. 
Gallic acid, when pure, is in the form of 
transparent plates or octahedrons. Its taste 
is acid, and somewhat astringent ; and when 
heated it has a peculiar and rather unpleasant 
aromatic odour. 
It is soluble in one and a half parts of boil- 
ing water, and in 12 parts of cold water. 
When this solution is heated, the acid under- 
goes a very speedy decomposition. Alco- 
hol dissolves one-fourth of its weight of this 
acid at the temperature of tiie atmosphere. - 
When boiling hot, it dissolves a quantity 
equal to its own weight. It is insoluble in 
ether. When exposed to the action of heat, 
it is sublimed without alteration : but a strong 
heat decomposes it in part, and converts it 
into an acid water, carbureted hydrogen gas, 
carbonic acid gas, oil, and charcoal. When 
distilled, a quantity of oxygen gas is disen- 
gaged, an acid liquor is found in the receiver, 
with some gallic acid not decomposed, and 
there remains in the retort a quantity of 
charcoal. If what has passed into the re- 
ceiver is again distilled, more oxygen gas is 
obtained, some gallic acid stilt sublimes, 
and a quantity of charcoal remains in the re- 
tort. By repeated distillations the whole of 
the acid may be decomposed. This decom- 
position may be more easily accomplished 
by distilling repeatedly a solution of gaTlic 
acid in water. The products are oxygen 
gas, charcoal, and an acid liquor. 
From these experiments it was concluded, 
that gallic acid is composed of oxygen, and 
a much larger proportion of carbon than en- 
ters into the composition of carbonic acid. 
But this conclusion is not warranted by the 
analysis: for the quantity of oxygen gas and 
carbon obtained was not equal to that of the 
gallic acid decomposed ; and in the acid li- 
quor which came over, there evidently ex- 
isted a quantity of water, which doubtless 
was- formed during the distillation. Scheele, 
by treating gallic acid with nitric acid in the 
usual manner, converted it into oxalic acid. 
Now it is certain that oxalic acid contains 
hydrogen as well as carbon. It cannot be 
doubted, then, that gallic acid is composed 
of oxygen, hydrogen, and carbon, in pro- 
portions not yet ascertained. But Mr. Dey- 
eux has proved, that the quantity of carbon 
is very great, compared with that of the hy- 
drogen. 
Gallic acid is not altered by exposure to 
the air. Neither oxygen gas, the simple 
combustibles, nor azote, seem to have any 
particular action on it. Its action on the 
metals has not been examined. It combines 
with alkalies, earths, and metallic oxides, 
and forms compounds called gall at s, most of 
which are still but very imperfectly known. 
As the greater number of its combinations 
with metallic oxides are insoluble, it for the 
most part occasions a precipitate when pour- 
ed into a solution containing a metal; and 
this precipitate differs in colour, according 
to the metal which occasions it. Hence 
this acid, or at least the infusion of nut-galls, 
is very much used by chemists to detect the 
presence of metals when held in solution. 
The formation of a precipitate, with infusion 
of nut-galls, is even considered as a property 
almost peculiar to metallic oxides. It ought 
to be remarked, however, that all the metals 
are by no means precipitated from their so- 
lutions by gallic acid. The following must 
be excepted: 
1. Platinum, 4. Cobalt, 
2. d in, 5. Manganese, 
3. Zinc, 6. Arsenic. 
The following Table exhibits a view of the 
colours of the precipitates of different metals 
by means of this acid : 
Gold 
Silver 
Mercury 
Copper - 
Iron 
Lead 
Brown 
Brown 
Orange yellow 
Brown 
Black 
White 
Nickel - 
Grey 
Bismuth 
Orange 
Antimony 
White 
Tellurium 
Yellow 
Uranium 
Chocolate 
Titanium 
Reddish brown 
Chromium 
Brown 
Coluinbium 
Orange 
Molybdic acid acquires a dark yellow co- 
lour, but does not precipitate. 
But the colour of these metallic precipi- 
tates varies considerably according to the 
state of oxydizement, and the acid with 
which they are composed. These differ- 
ences are especially remarkable in the solu- 
tions of mercury and copper. 
Gallic acid produces no change in the so- 
lutions of alkaline salts: But when dropt into 
barytes water, strontian water, or lime wa- 
ter, it gives them a bl.ueish-red colour, and 
occasions a flaky precipitate, composed of 
the acid combined with the earths. 
Gallic acid occasions a precipitate when 
poured into solutions of glucina, yttria, and 
zirconia in acids. This property distin- 
guishes these three bodies from all the other 
earths, none of which are precipitated from 
their solutions in acids by gallic acid. 
The affinities of. gallic acid are still unde- 
termined. Mr. Richter has shewn, that it 
is not capable of taking iron from sulphuric- 
acid, as has been hitherto supposed, unless 
it is assisted by the action of some other 
body which has an affinity for sulphuric 
acid. He has endeavoured to shew, too, 
contrary to the experiments of Proust, that 
it strikes a black with all the oxides of iron ; 
but his proofs are by no means sufficient to 
decide that point. 
GALLINiE, in ornithology, the fifth or- 
der of birds : the upper mandible is channel- 
led, extending with a margin above the 
lower, and a little bowed ; the nostrils are 
covered with a cartilaginous membrane ; 
they live upon grain, dust themselves, make 
an artless nest and lay many eggs. Under 
this order are comprehended the peacock, 
pheasant, turkey, the common dunghill cock, 
partridge, grous, dodo, curissoa, &e. 
GALLIUM, ladies bed-straw. See 
Galium. 
'GALLON, a measure of capacity both 
for dry and liquid articles, containing four 
quarts ; but these quarts, and consequently 
the gallon itself, are different, acc'ording to 
the quality of the thing measured; for in- 
stance, the wine gallon contains 231 cubic 
inches, and holds eight pounds five ounces 
and two-thirds avoirdupois, of pure water : 
the beer and ale gallon contains 282 solid 
inches, and holds ten pounds three ounces 
and a quarter avoirdupois, of w ater : and the. 
gallon for corn, meal, & c. two hundred and 
sixty eight cubic inches and four fifths, and 
holds nine pounds eleven ounces and a half 
of pure w ater. 
GALLON, in commerce, a narrow thick 
kind of ferret or lace, used to edge or border 
clothes, sometimes made of wool, and at 
others of gold or silver. 
GALOPINA, a genus of the tetandria 
digynia class and order. Cal. none ; coy. 
four-cleft ; seeds two, naked. A plant of 
the Cape. 
GALVANISM, a term used to denote 
the influence of metals by mere external con- 
tact with the animal body. In the yeae 
