Challenger Expedition, a circumnavigating scientific exploration of the open sea sent out by the British government in 1872-76—earlier expeditions being those of the Lightning (1868) and Porepine (1870). In 1872 the Challenger, a corvette of 2306 tons, was completely fitted out and furnished with every scientific appliance for examining the sea from surface to bottom—natural history work-room, chemical laboratory, aquarium, &c. The ship was given in charge to a naval surveying staff under Captain Nares; and to a scientific staff, with Professor (afterwards Sir) Wyville Thomson at their head, for the purpose of sounding the depths, mapping the basins, and determining the physical and biological conditions of the Atlantic, the Southern and the Pacific Oceans. With this new commission, the Challenger weighed anchor at Sheerness on the 7th December 1872, and on the evening of the 24th May 1876 she dropped anchor at Spithead, having in these three and a half years cruised over 68,900 nautical miles, and made investigations at 362 stations, at each of which were determined the depth of channel; the bottom, surface, and intermediate temperatures, currents, and fauna; and the atmospheric and meteorological conditions. The route was by Madeira, the Canaries, the West Indies, Nova Scotia, Bermudas, Azores, Cape Verd, Fernando Noronha, Bahia, Tristan d'Acunha, Cape of
Good Hope, Kerguelen, Melbourne, the Chinese Sea, Hong Kong, Japan, Valparaiso, Magellan's Strait, Monte Video, Vigo, and Portsmouth. Between the Admiralty Isles and Japan the Challenger made her deepest sounding, on the 23d March 1875, 4575 fathoms. See the copious Reports on the Scientific Results of the Voyage of H.M.S. Challenger, edited by Sir Wyville Thomson and Sir John Murray, which mark an era in deep-sea exploration. They extend in all to fifty volumes (1880-95), the bulk of the large quartos devoted to Zoology, the others representing Botany (3 vols.), Deep-sea Deposits (1 vol.), Physics and Chemistry (3 vols.), and a Narrative (2 vols.) To these invaluable reports many articles in the present work are indebted for materials and illustrations. See also the works of Sir C. Wyville Thomson, H. M. Moseley, Spry, Lord George Campbell, Wild; and the articles in this work on ATLANTIC OCEAN, PACIFIC OCEAN, SOUNDING, and especially SEA.