swan, common name for a large aquatic bird of both hemispheres, related to ducks and geese. It has a long, gracefully curved neck and an extremely long, convoluted trachea which makes possible its far-carrying calls. The orange-billed white trumpeter swan, Cygnus buccinator, seen in parks, is the mute swan, of Old World origin. It breeds in the wild state in parts of Europe, Asia, and the United States. During the breeding season it has a trumpetlike note, softer in the tame birds. The whistling swan migrates from the arctic to Mexico. Conservation measures saved the almost extinct trumpeter swan of North America, the largest species. Wild species in Europe include the whooper (or whooping) and the Bewick swans. The black swan, Chenopis atrata, is native to Australia, and the black-necked swan, Cygnus melancoriphus, to South America. The black swan has been domesticated. Swans are classified in the phylum Chordata, subphylum Vertebrata, class Aves, order Anseriformes, family Anatidae.

Swan, Sir Joseph Wilson, 1828-1914, English chemist and physicist. He made an incandescent lamp using a carbon filament (1860), 20 years before Edison's lamp. Noted for important contributions to photography as well, he devised the first commercially practical process for carbon printing, introduced the dry plate, and invented bromide paper. Swan also experimented with the production of man-made fibers. He was knighted in 1904.

Long-necked, heavy-bodied, big-footed waterfowl (genus Cygnus, family Anatidae). Among waterfowl, swans are the largest and fastest, both swimming and flying; at about 50 lbs (23 kg), the mute swan (C. olor) is the heaviest flying bird. Swans dabble in shallows for aquatic plants. Five all-white, black-legged species live in the Northern Hemisphere; a black and a black-necked species live in the Southern Hemisphere. Males (cobs) and females (pens) look alike. Swans mate for life. The cob keeps guard while the pen incubates, on average, six eggs on a heap of vegetation; the young (cygnets) are tended for several months. Their graceful form when swimming has made swans emblems of beauty for centuries.

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(born Oct. 31, 1828, Sunderland, Durham, Eng.—died May 27, 1914, Warlingham, Surrey) English physicist and chemist. By 1871 he had invented the dry photographic plate, an important improvement in photography. He had already produced an early electric lightbulb (1860), and in 1880, independently of Thomas Alva Edison, he produced a carbon-filament incandescent electric lamp. He also patented a process for squeezing nitrocellulose through holes to form fibres, a process that became widely employed in the textile industry.

Learn more about Swan, Sir Joseph (Wilson) with a free trial on Britannica.com.

(born Oct. 31, 1828, Sunderland, Durham, Eng.—died May 27, 1914, Warlingham, Surrey) English physicist and chemist. By 1871 he had invented the dry photographic plate, an important improvement in photography. He had already produced an early electric lightbulb (1860), and in 1880, independently of Thomas Alva Edison, he produced a carbon-filament incandescent electric lamp. He also patented a process for squeezing nitrocellulose through holes to form fibres, a process that became widely employed in the textile industry.

Learn more about Swan, Sir Joseph (Wilson) with a free trial on Britannica.com.