ASCENSION, an island in the Atlantic Ocean, between 7° 53′ and 8° S., and 14° 18′ and 14° 26′ W., 800 m. N.W. of St Helena, about 7½ m. in length and 6 in breadth, with an area of 38 sq. m. and a circumference of about 22 m. The island lies within the immediate influence of the south-east trade-wind. The lee side of the island is subject to the visitation of “rollers,” which break on the shore with very great violence. Ascension is a volcanic mass erected on a submarine platform. Numerous cones exist. Green Mountain, the principal elevation, is a huge elliptical crater, rising 2820 ft. above the sea, while the plains or table-lands surrounding it vary in height from 1200 to 2000 ft. On the north side they sweep gradually down towards the shore, but on the south they terminate in bold and lofty precipices. Steep and rugged ravines intersect the plains, opening into small bays or coves on the shore, fenced with masses of compact and cellular lava; and all over the island are found products of volcanic action. Ascension was originally destitute of vegetation save on the summit of Green Mountain, which owes its verdure to the mists which frequently enshroud it, but the lower hills have been planted with grasses and shrubs. The air is clear and light, and the climate remarkably healthy, notwithstanding the high temperature—the average day temperature on the shore being 85° F., on Green Mountain 75° F. The average rainfall is about 20 in., March and April being the rainy months. Ascension is noted for the number of turtles and turtle eggs found on its shores, the season lasting from December to May or June. The turtles are caught and kept in large ponds. The coasts abound with a variety of fish of excellent quality, of which the most important are the rock-cod, the cavalli, the conger-eel and the “soldier.” Numbers of sheep are bred on the island, and there are a few cattle and deer, besides goats and wild cats. Feathered game is abundant. Like St Helena, the island does not possess any indigenous vertebrate land fauna. The “wideawake” birds frequent the island in large numbers, and their eggs are collected and eaten. Beetles and land-shells are well represented. Flies, ants, mosquitoes, scorpions, centipedes and crickets abound. The flora includes purslane, rock roses and several species of ferns and mosses.

The island was discovered by the Portuguese navigator, João da Nova, on Ascension Day 1501, and was occasionally visited thereafter by ships. In 1701 William Dampier was wrecked on its coast, and during his detention discovered the only spring of fresh water the island contains. Ascension remained uninhabited till after the arrival of Napoleon at St Helena (1815), when it was taken possession of by the British government, who sent a small garrison thither. A settlement, named George Town (locally known as Garrison), was made on the north-west coast, water being obtained from “Dampier’s” springs in the Green Mountain, 6 m. distant. The island is under the rule of the admiralty, and was likened by Darwin to “a huge ship kept in first-rate order.” It is governed by a naval captain borne on the books of the flagship of the admiral superintendent at Gibraltar. A depot of stores for the navy is maintained, but the island is used chiefly as a sanatorium. Ascension is connected by cable with Europe and Africa, and is visited once a month by mail steamers from the Cape. Formerly letters were left by passing ships in a crevice in one of the rocks. The population, about 300, consists of seamen, marines, and Krumen from Liberia.

See Africa Pilot, part ii., 5th ed. (London, 1901); C. Darwin, Geological Observations on the Volcanic Islands visited during the Voyage of H.M.S. “Beagle” (London, 1844); Report of the Scientific Results of the Voyage of the “Challenger,” vol. i. part 2 (London, 1885); and Six Months in Ascension, by Mrs Gill (London, 1878), an excellent sketch of the island and its inhabitants. It was at Ascension that Mr, afterwards Sir, David Gill determined, in 1877, the solar parallax.