Encyclopædia Britannica Australia -

Encyclopedias since 1768

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heat ... Hecker, Isaac Thomas

heat: energy that is transferred from one body to another as the result of a difference in temperature. If two bodies at different temperatures are brought together, energy is transferred-i.e., heat flows-from the hotter body to the colder. The effect of ...
heat capacity: ratio of heat absorbed by a material to the temperature change. It is usually expressed as calories per degree in terms of the actual amount of material being considered, most commonly a mole (the molecular weight in grams). The heat ...
heat exchanger: any of several devices that transfer heat from a hot to a cold fluid. In many engineering applications it is desirable to increase the temperature of one fluid while cooling another. This double action is economically accomplished by a heat ...
heat pipe: form of heat exchanger (q.v.) useful for transporting heat over relatively large distances with a small temperature difference.
heat pump: device for transferring heat from a substance or space at one temperature to another substance or space at a higher temperature. It consists of a compressor, a condenser, a throttle or expansion valve, an evaporator, and a working fluid (refrigerant), ...
heat transfer: any or all of several kinds of phenomena, considered as mechanisms, that convey energy and entropy from one location to another. The specific mechanisms are usually referred to as convection, thermal radiation (qq.v.), and conduction (see thermal conduction). Conduction involves ...
heath: any of the low evergreen shrubs of the genus Erica, of the family Ericaceae, with about 500 species, most of which are indigenous to South Africa. Some heaths also occur in the Mediterranean region and in northern Europe, and species ...
Heath, Sir Edward: Conservative prime minister of Great Britain from 1970 to 1974.
Heathcoat, John: pioneering English inventor of lace-making machinery.
heather: (species Calluna vulgaris), low evergreen shrub of the heath family (Ericaceae), widespread in western Europe and Asia, North America, and Greenland. It is the chief vegetation on many wastelands of northern and western Europe. C. vulgaris is distinguished from true ...
heating: process and system of raising the temperature of an enclosed space for the primary purpose of ensuring the comfort of the occupants. By regulating the ambient temperature, heating also serves to maintain a building's structural, mechanical, and electrical systems.
heatstroke: condition caused by continuous exposure to high temperature and humidity for several hours. The term sunstroke refers to the same disorder when exposure to direct sunlight is the main cause of the condition. The primary feature of heatstroke is an ...
heaven: the dwelling place of God, gods, or other spiritual beings and the abode or state of being of the saved, the elect, or the blessed in the afterlife or in the time after the Last Judgment. The term also designates ...
Heaven's Gate: religious group founded in the United States on a belief in unidentified flying objects. Under a variety of names over the years, including Human Individual Metamorphosis, Bo and Peep, and Total Overcomers Anonymous, the group advocated extreme self-renunciation to the ...
heaves: chronic disorder of the lungs of horses and cows, characterized by difficult breathing and wheezy cough. The symptoms are worsened by vigorous exercise, sudden weather changes, and overfeeding. Heaves resulting from bronchitis may be associated with the feeding of dusty ...
Heaviside, Oliver: physicist who predicted the existence of the ionosphere, an electrically conductive layer in the upper atmosphere that reflects radio waves. In 1870 he became a telegrapher, but increasing deafness forced him to retire in 1874. He then devoted himself to ...
heavy ion: in nuclear physics, any particle with one or more units of electric charge and a mass exceeding that of the helium-4 nucleus (alpha particle). Special types of accelerators are capable of producing fairly intense, high-energy beams of heavy ions, which ...
heavy metal: genre of rock music that includes a group of related styles that are intense, virtuosic, and powerful. Driven by the aggressive sounds of the distorted electric guitar, heavy metal is arguably the most commercially successful genre of rock music.
heavy oil and tar sand: crude oils below 20° API gravity are usually considered to be heavy. The lighter conventional crudes are often waterflooded to enhance recovery. The injection of water into the reservoir helps to maintain reservoir pressure and displace the oil toward the ...
heavy water: water composed of deuterium, the hydrogen (q.v.) isotope with a mass double that of ordinary hydrogen, and oxygen. (Ordinary water has a composition represented by H₂O.) Thus, heavy water has a molecular weight of about 20 (the sum of twice ...
Heb-Sed: one of the oldest feasts of Egypt, celebrated by the king after 30 years of rule and repeated every three years thereafter. The festival was in the nature of a jubilee, and it is believed that the ceremonies represented a ...
Hebat: in the religions of Asia Minor, a Hurrian goddess, the consort of the weather god Teshub. She was called Queen of Heaven and was assimilated by the Hittites to their national goddess, the sun goddess of Arinna. Teshub and Hebat ...
Hebbel, Friedrich: poet and dramatist who added a new psychological dimension to German drama and made original use of Hegel's concepts of history to dramatize conflicts in his historical tragedies. He was concerned not so much with the historical aspects of the ...
Hebe: (from Greek hebe, "young maturity," or "bloom of youth"), daughter of Zeus, the chief god, and his wife Hera.
Heber City: city, seat (1862) of Wasatch county, northern Utah, U.S. Named in 1859 to honour Mormon leader Heber C. Kimball, the original town site contained a fort to protect settlers from Indian attacks, as well as a handful of homes. The ...
Hebert, Anne: French-Canadian poet, novelist, and playwright noted as an original literary stylist. She lived most of her adult life in Paris.
Hebert, Jacques-Rene: political journalist during the French Revolution who became the chief spokesman for the Parisian sansculottes (extreme radical revolutionaries). He and his followers, who were called Hebertists, pressured the Jacobin regime of 1793-94 into instituting the most radical measures of the ...
Hebertist: any of the group of extremists of the French Revolution, followers of Jacques-Rene Hebert, who demanded a Revolutionary government that was anti-Christian and dedicated to the eradication of Girondists and other moderates.
Hebra, Ferdinand von: physician who founded the New Vienna school of dermatology, which became a basis for modern dermatology.
Hebraic law: body of ancient Hebrew law codes found in various places in the Old Testament and similar to earlier law codes of ancient Middle Eastern monarchs-such as the Code of Hammurabi, an 18th-17th-century-BC Babylonian king, and the Code of Lipit-Ishtar, a ...
Hebrew: any member of an ancient northern Semitic people that were the ancestors of the Jews. Historians use the term Hebrews to designate the descendants of the patriarchs of the Old Testament (i.e., Abraham, Isaac, and so on) from that period ...
Hebrew alphabet: either of two distinct Semitic alphabets-the Early Hebrew and the Classical, or Square, Hebrew. Early Hebrew was the alphabet used by the Jewish nation in the period before the Babylonian Exile-i.e., prior to the 6th century BC-although some inscriptions in ...
Hebrew language: Semitic language of the Northern Central (also called Northwestern) group; it is closely related to Phoenician and Moabite, with which it is often placed by scholars in a Canaanite subgroup. Spoken in ancient times in Palestine, Hebrew was supplanted by ...
Hebrew literature: the body of written works produced in the Hebrew language and distinct from Jewish literature, which also exists in other languages.
Hebrew Union College: the oldest Jewish seminary in the United States for the training of rabbis, long a stronghold of American Reform Judaism. It was founded in 1875 at Cincinnati, Ohio, by Rabbi Isaac Mayer Wise, and it became the major training centre ...
Hebrew University of Jerusalem: state-subsidized institution of higher learning in Jerusalem. The foremost university in Israel, it attracts many Jewish students from abroad. Originally inaugurated (1925) on Mount Scopus, it was transferred to Giv'at Ram in the Israeli-controlled sector of Jerusalem after 1948, when ...
Hebrews, Letter to the: New Testament letter traditionally attributed to Paul but now widely believed to be the work of a Jewish Christian, perhaps one of Paul's associates. The letter was composed sometime during the latter half of the 1st century. To judge from ...
Hebrides: group of islands extending in an arc off the Atlantic (west) coast of Scotland. They are subdivided into two groups-the Inner Hebrides to the east and the Outer Hebrides to the west-which are separated from each other by the channels ...
Hebron: city in the southern Judaean Hills, south-southwest of Jerusalem. It is 3,050 feet (930 m) above sea level. In modern times, it was part of mandated Palestine during 1923-48; after the Arab-Israeli War of 1948-49, it was in the territory ...
Hecataeus Of Miletus: Greek author of an early history and of a book of travels. During the time of the Persian invasion, he tried to dissuade the Ionians from revolt against Persia, and in 494, when they were obliged to sue for terms, ...
Hecate: (from Greek hekate, "she who works her will"), goddess accepted at an early date into Greek religion but probably derived from the Carians in southwest Asia Minor. In Hesiod she is the daughter of the Titan Perses and the nymph ...
Hecate Strait: passage of the eastern North Pacific, off central British Columbia, Canada. Stretching south from Dixon Entrance 160 mi (260 km) to Queen Charlotte Sound, the waterway, which ranges in width from 40 to 80 mi, separates the Queen Charlotte Islands ...
Hecatompylos: ancient Parthian city in western Khurasan and capital of the Iranian Arsacid dynasty. It might have already fallen into decline when the Seleucids revived it as a military outpost about 300 BC. By about 200 BC it was the Arsacid ...
Hechingen: city, Baden-Wurttemberg Land (state), southwestern Germany. It lies in the Swabian Alp, southwest of Tubingen. From the 13th century it was the seat of the counts of Zollern (after 1623, princes of Hohenzollern-Hechingen); it passed to Prussia ...
Hecht, Anthony: American poet whose elegant tone, mastery of many poetic forms, and broad knowledge and appreciation of literary tradition lent his poetry great richness and depth. He was awarded the Pulitzer Prize in 1968.
Hecht, Ben: U.S. novelist, playwright, and film writer who, as a newspaperman in the 1920s, perfected a type of human interest sketch that was widely emulated. His play The Front Page (1928), written with Charles MacArthur, influenced the public's idea of the ...
Hechtia: genus of semidesert plants of the pineapple family (Bromeliaceae), consisting of about 35 New World species, chiefly tropical. Several species are cultivated indoors as ornamentals.
Heckel, Erich: German painter, printmaker, and sculptor who was one of the founding members of Die Brucke ("The Bridge"), an influential group of German Expressionist artists. He is best known for his paintings and bold woodcuts of nudes and landscapes.
heckelphone: double-reed woodwind instrument resembling the baritone oboe. It was perfected by Wilhelm Heckel in 1904 as a result of a request from the composer Richard Wagner about 20 years earlier for a low-register instrument combining the qualities of the oboe ...
Hecker, Friedrich: German revolutionary republican politician who led radical forces that demanded that the 1848 revolution establish a republican form of government in Germany.
Hecker, Isaac Thomas: Roman Catholic priest who founded the Paulist Fathers, a diocesan organization for missionary work in New York.