Encyclopaedia Britannica > Volume 3, Anatomy-Astronomy

A E C
Arcos at first occasioned no small alarm in the British garrison.
H Of the ultimate fate of these expensive and formidable en-
Arcy- gines all British readers must be sufficiently informed. Not
one of the whole ten escaped destruction from the bombs
and red-hot balls poured upon them from the garrison. M.
d’Ar^on, however, published a memoir to show that his bat¬
teries were wilfully exposed to destruction through the envy
and jealousy which the contrivance had excited among the
Spaniards; and this statement, whatever may have been
its real value, seems to have obtained the general concur¬
rence of his countrymen.
M. d’Ar^on appeared in the capacity of a general in the
first years of the Revolution ; and, in particular, was em¬
ployed in the invasion of Holland, where, in 1793, he be¬
sieged and took several fortified places. He soon afterwards
withdrew or was driven from public life, and remained in
retirement till 1799, when he was made a member of the
Conservative Senate by Buonaparte. He died the follow¬
ing year, aged sixty-seven.
ARC OS de la Frontera, a Spanish town in the pro¬
vince of Cadiz, between Ronda and Santa Maria. It is
situated on the banks of the river Guadalete, celebrated for
that decisive battle of three days’ continuance, near Xeres,
by which the crown of the Gothic kings of Spain was trans¬
ferred to the Arabian invaders. It contains two parish
churches, seven monasteries, 1334 houses, and 12,000 in¬
habitants. Long. 5. 55. W. Lat. 36. 39. N.
ARCOT, a city of Hindustan, capital of a district of the
same name, is situated on the S. side of the river Palar. Ar-
cot is supposed to have been the capital of the Sorae, or the
Soramundalum of Ptolemy, whence, by an easy derivation,
Coromandel; but the present town is entirely of modern
date. The Mogul armies, after they had captured Gingee,
found the situation so unhealthy that they were forced to
remove to the plains of Arcot, and began to build the pre¬
sent town about the year 1716. The nabob of Arcot, An-
wanud Deen, being killed in battle in 1749, the place was
taken by his competitor, who was supported by the French.
In 1751 it was retaken by Colonel Clive, with 500 troops,
from a garrison of 1100 men ; and here that gallant soldier
maintained himself for fifty days against the attacks of the
French and their Indian allies, who were finally compelled
to raise the siege. It was afterwards taken by the French,
but was recaptured in 1760 by Colonel Coote, after the
battle of Wandewash. Hyder Ali gained possession of it
for a time after he had defeated the British under Colonel
Baillie in 1780. Long. 79. 25. E. Lat. 12. 56. N.
ARCTIC, in Astronomy, an epithet given to the north
pole, or the pole raised above our horizon. It is called the
arctic pole, from the constellation of the little bear ; called
in Greek, apuTos, the last star in the tail of which nearly
points out the north pole.
Arctic Circle is a lesser circle of the sphere, parallel to
the equator, and 23° 30' distant from the north pole; from
whence its name. This, and its opposite the antarctic, are
called the two polar circles, and may be conceived to be
described by the motion of the poles of the ecliptic round
the poles of the equator, or of the world.
Arctic Regions. See Polar Regions.
ARCTURUS, in Astronomy, a fixed star of the first
magnitude, in the constellation Arctophylax, or Bootes. The
word is formed of ap/cros, bear, and ovpd, tail, bear’s tail, in
reference to its position.
ARC Y, Grotte d’, a vast stalactitic cavern in the French
department of Yonne, divided into many compartments, one
of which is 1200 feet long, 85 feet high, and 40 feet wide.
Arcy, Patrick r>’, member of the Academy of Sciences
of Paris, a general officer in the French army, Chevalier of
the order of St Louis, &c., was born in Ireland in 1725. His
parents, in consequence of their attachment to the house of
A R D 519
Stuart, left Ireland, and settled in France. He studied Ardea
mathematics with distinguished success under Clairaut the 11
elder, and had for his fellow-student the celebrated Clairaut, Ardee' y
the son. He obtained a commission in the French army,
and in 1746 was embarked in the expedition which was
intended to make a descent into Scotland. He was made
prisoner, and was treated like other prisoners of war, no no¬
tice being taken of his having been born a British subject.
He continued attached to the house of Stuart during the
whole of his life.
In 1760 he published his Essay on Artillery. To esti¬
mate the force of the explosion of gunpowder, he employed
a cannon suspended so that the arc of vibration described
by it on its being fired was a measure of the force of explo¬
sion. To measure the initial velocity of a projectile, he used
Robins’s machine. Robins showed, that when the velocity
of a projectile is great, the resistance opposed by the air is
not in proportion to the square of the velocity, as is the
case when the velocity is small. D’Arcy made experiments
with a view of ascertaining this law, but without success.
His work contains an account of experiments made by him
to determine the most advantageous length of cannon. He
published a paper on hydraulic machines in 1754, where he
treats of the maximum of effect of water-wheels. He also
published a paper concerning the duration of the impression
of light on the retina. He found that the revolution of a
luminous point must be rapid, so as to be performed in roths
of a second at the least, in order to produce the appearance
of a continued luminous circle.
D’Arcy was of a handsome figure, and passed much of his
time in the gay world. A short time before his death, he
married a young lady, his niece, and took the title of Count.
He died in 1779. (w. A. c.)
ARDEA, or Ardua, a very ancient city of Latium, the
capital of the Rutuli, on the river Numicus. It is now a vil¬
lage with 200 inhabitants, in the midst of pestilential swamps.
ARDEBIL, or Ardebeel, a town of Persia, in the pro¬
vince of Azerbijan, on a river which runs into the Aras or
Araxes. It is situated on the southern side of the desert
plain of Ardebil, which is 60 miles in length by 40 in breadth.
The town contains about 500 or 600 families, and appears
to have been built from some former city. It is surrounded
by a ruinous wall of mud, flanked with towers in a like state
of decay. It has a fort, which is a regular square, with bas¬
tions at the corners, fortified according to the European
fashion. The only objects of interest are the tombs of Sheik
Suffee, the ancestor of the Suffanean kings, and his descen¬
dants. It is still held in veneration as having been the resi¬
dence of that prince.
ARDECHE, a department in the south of France, for¬
merly Vivarais. The granitic chain of the Cevennes occu¬
pies a large part of it. The culminating point of that group
is 5970 feet above the sea, and is named Mount Mezenc.
Sandstone forms the lower portions of the district, over which
lie beds of a coal formation, limestone, and chalk; but the
continuity of these beds is disturbed by the cones of extinct
volcanoes, part of the remarkable belt that passes from Puy
de Dome, through Cantal and Haute Loire, towards the
Rhone at Rochemaure. The surface = 2081 square miles;
and the population, by the census of 1851, 386,505. The
department contains three arrondissements ; Tournon, Lar-
gentiere, and Privas. Its chief rivers are the Rhone, Loire,
Gance, Doux, Erieux, and Ardeche. The mineral products
are iron, antimony, coal, &c. Wine, chesnuts, and olives, are
abundant, but corn is rather deficient. The mulberry is
much cultivated for the rearing of silkworms.
ARDEE, a town of Ireland, county of Louth, on the river
Dee, whence its ancient name of Atherdee, “ I own on the
Dee.” It was formerly a place of considerable importance,
but now consists chiefly of miserable cabins. It has two old