Haley, Sir William (John) (b. May 24, 1901, Jersey, Channel Islands—d. Sept. 6, 1987, Jersey) English journalist and editor. Haley began to study journalism in 1918 and joined the staff of the Manchester Evening News in 1922. He held the post of director of the Manchester Guardian and Evening News before becoming director general of the BBC (1944-52) and then editor of The Times of London (1952-66), the most important and influential position in British journalism.
half-life Interval of time required for one-half of the atomic nuclei of a radioactive sample to decay (change spontaneously into other nuclear species by emitting particles and energy), or the time required for the number of disintegrations per second of a radioactive material to decrease by one-half. Half-lives are characteristic properties of the various unstable atomic nuclei and the particular way in which they decay. Alpha decay and beta decay are generally slower processes than gamma decay.
halftone process In printing, a technique of breaking up an image into a series of dots to permit reproduction of the full tone range of a photo¬ graph or artwork. It is traditionally done by placing a glass screen printed with a tight grid of lines over the plate being exposed. The grid breaks up the image into hundreds of tiny dots, each of which is read by the camera as either black or white—or, in the case of colour art, as either a single printing colour or white. The resulting image, called a halftone, is then rephotographed for printing. Screens are made with a varying num¬ ber of lines per inch, depending on the application; for newspapers the range is about 80-120, whereas glossy magazines usually require 133— 175 lines per inch.
Haliburton, Thomas Chandler (b. Dec. 17, 1796, Windsor, Nova Scotia—d. Aug. 27, 1865, Isleworth, Middlesex, Eng.) Canadian writer. He served in the legislature of his native Nova Scotia and later served as a judge of the Supreme Court (1841-54), where he maintained the strong conservatism that informs his writings. He moved to England in 1856 and was a member of Parliament from 1859 until his death. He is best known for creating the character Sam Slick, a Yankee clock peddler and cracker- barrel philosopher whose escapades first appeared in the newspaper Nova Scotian and were later published in The Clockmaker (1836, 1838, 1840) and other volumes.
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halibut ► Hall effect I 829
halibut Any of various flatfishes, especially the Atlantic and Pacific hal¬ ibuts (genus Hippoglossus, family Pleuronectidae), both of which have eyes and colour on the right side. The Atlantic halibut, found on both sides of the North Atlantic Ocean, is the largest flatfish; it may reach a length of about 7 ft (2 m) and a weight of 720 lb (325 kg). It is brown, black¬ ish, or deep green on the eyed side. The smaller and slimmer Pacific hali¬ but is found on both sides of the North Pacific Ocean. Other edible halibut include the Greenland halibut, of Arctic and near-Arctic parts of the Atlan¬ tic, and the California halibut (family Bothidae), found along the Cali¬ fornia coast.
Halicarnassus \,ha-l3-kar-'na-s3s\ modern Bodrum \bo-'drum\ Ancient Greek city, western Anatolia. Located in modem Turkey on a peninsula in the Aegean Sea, it became the capital of Caria (c. 370 bc) under the Persian satrap Mausolus, who built a great wall, public build¬ ings, and a secret dockyard and canal. His widow erected (c. 350 bc) a great tomb (the Mausoleum) in his memory. It was one of the Seven Won¬ ders of the ancient world, and its remains are now in the British Museum. Halicarnassus was the birthplace of the Greek historian Herodotus. It came under Roman rule in 129 bc, and in early Christian times was a bishop¬ ric. The ruins of the castle of the Knights of St. John, founded c. ad 1400, dominate the ancient site.
halide mineral Vha-.lld, 'ha-.lIdV Any of a group of naturally occurring inorganic compounds that contain a halogen such as fluorine, chlorine, iodine, or bromine as the anion. Such compounds, with the notable excep¬ tions of fluorite, haute, and sylvite, are rare and of very local occurrence.
Halifax City (pop., 2001: 119,292), capital of Nova Scotia, Canada. Located on Halifax Harbour, an inlet of the Atlantic Ocean, it was settled by the British in 1749 as a counter¬ balance to French holdings at Cape Breton. It served as a British army and navy base until its defenses were taken over by the Canadian govern¬ ment in 1906. The city suffered from a munitions-ship explosion in 1917 that killed nearly 2,000 people. Dur¬ ing World Wars I and II, Halifax was Canada’s most important naval base.
The city is Nova Scotia’s leading commercial and industrial centre, and its port is one of the busiest in Canada. Its educational institutions include Dalhousie University (1818); historic buildings include St. Paul’s Church (1750), Canada’s oldest Protestant church. In 1996 Halifax amalgamated with several surround¬ ing communities to form Halifax Regional Municipality (pop., 2001:
359,183).
Halifax, Edward Frederick Lindley Wood, 1st earl of (b.
April 16, 1881, Powderham Castle, Devonshire, Eng.—d. Dec. 23, 1959, Garroby Hall, near York, Yorkshire) British statesman. He was elected to Parliament in 1910. As viceroy of India (1925-31), he worked on terms of understanding with Mohandas K. Gandhi and accelerated constitutional advances. His tenure as foreign secretary (1938—40) in Neville Chamber¬ lain’s government was controversial because of Chamberlain’s policy of appeasement toward Adolf Hitler, but Halifax kept the post into Winston Churchill’s ministry. As ambassador to the U.S. (1941^-6), he greatly served the Allied cause in World War II, for which he was created earl of Halifax in 1944.
halite Vha-.llt, 'ha-.lItX Naturally occurring sodium chloride (NaCl), com¬ mon or rock salt. Halite occurs on all continents, in beds that range from a few feet to more than 1,000 ft (300 m) in thickness. Termed evaporite deposits because they formed by the evaporation of saline water in par¬ tially enclosed basins, they characteristically are associated with beds of limestone, dolomite, and shale. Halite is found in large deposits in New York and in Russia, France, India, and Canada.
Hall, Charles Martin (b. Dec. 6, 1863, Thompson, Ohio, U.S.—d. Dec. 27, 1914, Daytona Beach, Fla.) U.S. chemist. He attended Oberlin College, where, soon after graduating in 1885, he discovered the method
of producing aluminum by electrolysis (simultaneously with Paul Heroult), an innovation that brought the metal into wide commercial use. Supported by the Mellon family, he formed the Pittsburgh Reduction Co. (later Alcoa). The need for cheap and plentiful power led the company to Nia¬ gara Falls, where in 1895 it became the first customer for Niagara’s new power plant.
Hall, G(ranville) Stanley (b. Feb. 1, 1844, Ashfield, Mass., U.S.—d. April 24, 1924, Worcester, Mass.) U.S. psychologist. He studied in Ger¬ many under Wilhelm Wundt and Hermann von Helmholtz and returned to the U.S. to earn the first psychology Ph.D. granted in America (Harvard, 1878). After teaching at Johns Hopkins University, he helped establish Clark University (1888) in Worcester, Mass., and worked there to shape experimental psychology into a science. He is frequently regarded as the founder of child psychology and educational psychology; he also did much to direct the ideas of Charles Darwin and Sigmund Freud into the psychological currents of his time. He founded several journals, includ¬ ing the American Journal of Psychology, and he helped found the Ameri¬ can Psychological Association, of which he was the first president. Hall’s work gave early impetus and direction to the development of psychology in the U.S.
hall, hypostyle See hypostyle hall
Hall, Sir James (b. Jan. 17, 1761, Dunglass, East Lothian, Scot.—d. June 23, 1832, Edinburgh) Scottish geologist and physicist. He founded experimental geology by artificially producing various rock types in the laboratory. He saw that he could obtain different kinds of rocks by melt¬ ing minerals and cooling them at a controlled rate. Later he produced a rock that closely resembled natural marble by heating calcium carbonate under pressure. He experimented extensively with igneous rocks from Scotland and showed that they had been produced by intense heat.