Arcos´ de la Fronte´ra, a city of Spain, 30 miles E. by N. from Cadiz, on the Guadalete, here crossed by a stone bridge, on a sandstone rock 570 feet above the level of the river. On the highest part of the rock stands the castle of the dukes of Arcos, partly in ruins. The principal manufactures are leather, hats, and cordage. Pop. 13,980.
Ar´cot, two districts and a town of India, within the Presidency of Madras.—North Arcot is an inland district with an area of 7616 sq. miles. The country is partly flat and partly mountainous, where intersected by the Eastern Gháts. Pop. 2,200,000.—South Arcot lies on the Bay of Bengal, and has two seaports, Cuddalor and Porto Novo. Area 5217 sq. miles. Pop. 2,170,000.—The town Arcot is in North Arcot, on the Palar, about 70 miles W. by S. of Madras. There is a military cantonment at 3 miles' distance. The town contains handsome mosques, a nabob's palace in ruins, and the remains of an extensive fort. Arcot played an important part in the wars which resulted in the ascendancy of the British in India. It was taken by Clive, 31st Aug., 1751, and heroically defended by him against an apparently overwhelming force under Raja Sahib. Pop. 11,475.
Arctic (a˙rk´tik), an epithet given to the north pole from the proximity of the constellation of the Bear, in Greek called arktos. The Arctic Circle is an imaginary circle on the globe, parallel to the equator, and 23° 28´ distant from the north pole. This and its opposite, the Antarctic, are called the two polar circles.
Arctic Expeditions. See North Polar Expeditions.
Arctic Ocean, that part of the water surface of the earth which surrounds the north pole, and washes the northern shores of Europe, Asia, and America; its southern boundary roughly coinciding with the Arctic Circle (lat. 66° 30´ N.). It encloses many large islands, and contains large bays and gulfs which deeply indent the northern shores of the three continents. Its great characteristic is ice, which is perpetual nearly everywhere.
Arctic Regions, the regions round the north pole, and extending from the pole on all sides to the Arctic Circle in lat. 66° 30´ N. The Arctic or North Polar Circle just touches the northern headlands of Iceland, cuts off the southern and narrowest portion of Greenland, crosses Fox's Strait north of Hudson's Bay, whence it goes over the American continent to Behring's Strait. Thence it runs to Obdorsk at the mouth of the Obi, then crossing Northern Russia, the White Sea, and the Scandinavian Peninsula, returns to Iceland. Though much skill and heroism have been displayed in the exploration of this portion of the earth, there is still an area round the pole estimated at 2,500,000 sq. miles, which is a blank to geographers. Many have adopted the belief in the existence of an open polar sea about the north pole. But this belief is not supported by any positive evidence. Valuable minerals, fossils, &c., have been discovered within the Arctic regions. In the archipelago north of the American continent excellent coal frequently occurs. The mineral cryolite is mined in Greenland. Fossil ivory is obtained in islands at the mouth of the Lena. In Scandinavia, parts of Siberia, and north-west America, the forest region extends within the Arctic Circle. The most characteristic of the natives of the Arctic regions are the Esquimaux. The most notable animals are the white-bear, the musk-ox, the reindeer, and the whalebone whale. Fur-bearing animals are numerous. The most intense cold ever registered in those regions was 74° below zero F. The aurora borealis is a brilliant phenomenon of Arctic nights. See North Polar Expeditions.
Arc´tium. See Burdock.
Arc´tomys. See Marmot.
Arctu´rus, or Alpha Boötis, a fixed star of the first magnitude in the constellation of Boötes (the Ploughman), is one of the brightest stars in the northern heavens, yellow in colour. Its light is believed to be intrinsically at least 140 times as brilliant as the sun's, and to take over 40 years to reach us. It is notable as having a comparatively large proper motion.
Ardahan´, a small fortified town about 6400 feet above the sea, between Kars and Batúm in Armenia. It was captured by the Russians in 1877, and ceded to them by the Berlin Treaty, 1878. It was handed over to Turkey by the Treaty of Brest-Litovsk in 1918, but the Turkish troops evacuated it after the armistice in 1918.