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  • Heldenleben, Ein (work by Strauss)

    Richard Strauss: Life: …Quixote and Ein Heldenleben (A Hero’s Life). In 1904 he and Pauline, who was the foremost exponent of his songs, toured the United States, where in New York City he conducted the first performance of his Symphonia Domestica (Domestic Symphony). The following year, in Dresden, he enjoyed his first…

  • Heldenlieder (German literature)

    Heldenlieder, body of short, poignant poetic songs celebrating dramatic, and usually tragic, episodes in the lives of the Germanic heroes. Other themes concerned pagan religious ritual, battle songs, and laments for the dead. The heroic lay originated c. 375–500, during the period of the great

  • Heldensage (work by Roland Holst-van der Schalk)

    Henriëtte Goverdina Anna Roland Holst-van der Schalk: …Communism in her poems in Heldensage (1927; “Heroic Saga”). She withdrew from active politics but in her later work remained loyal to her ideals, and her pacifist and anticolonial sentiment attracted much attention. She also wrote biographies of such figures as Jean-Jacques Rousseau (1912), Leo Tolstoy (1930), Romain Rolland (1946),…

  • Helder, Den (Netherlands)

    Den Helder, gemeente (municipality) and port, northwestern Netherlands, at the northern end of the North Holland Canal, opposite Texel Island on the Marsdiep, a channel linking the North Sea and Waddenzee. Offshore, in 1673, a Dutch fleet under Adm. Michiel A. de Ruyter and Cornelis Tromp defeated

  • Helen (American writer and critic)

    Sarah Helen Power Whitman, American poet and essayist, noted for her literary criticism and perhaps best remembered for her alliance with and scholarly defense of Edgar Allan Poe. Sarah Power from an early age was an avid reader of novels and of poetry, especially that of Lord Byron. In 1828 she

  • Helen (play by Euripides)

    Helen, play by Euripides, performed in 412 bce. In this frankly light work, Euripides deflates one of the best-known legends of Greek mythology, that Helen ran off adulterously with Paris to Troy. In Euripides’ version, only a phantom Helen goes with Paris, and the real woman pines faithfully in

  • Helen Keller International (international organization)

    Helen Keller International (HKI), one of the oldest international nonprofit organizations working to prevent blindness and fight malnutrition. Headquarters are in New York City. In 1915 the American merchant George Kessler and his wife, Cora Parsons Kessler, organized in Paris the British, French,

  • Helen Lester (work by Alden)

    Isabella Macdonald Alden: Her first novel, Helen Lester, appeared in 1866 after a friend submitted it without her knowledge to a competition for a book explaining the scheme of Christian salvation to children. In that same year she married the Reverend Gustavus R. Alden, with whom she traveled to a succession…

  • Helen O’Loy (short story by del Rey)

    science fiction: Alien encounters: …del Rey’s short story “Helen O’Loy” (1938). Helen was not the first female robot—her famous predecessor is the sinister celluloid robot Maria from the aforementioned film Metropolis (1927). Helen, by contrast, somehow establishes her womanhood by marrying her inventor and then sacrificing her own mechanical life upon her husband’s…

  • Helen of Troy (Greek mythology)

    Helen of Troy, in Greek legend, the most beautiful woman of Greece and the indirect cause of the Trojan War. She was daughter of Zeus, either by Leda or by Nemesis, and sister of the Dioscuri. As a young girl, she was carried off by Theseus, but she was rescued by her brothers. She was also the

  • Helen of Troy (Greek mythology)

    Helen of Troy, in Greek legend, the most beautiful woman of Greece and the indirect cause of the Trojan War. She was daughter of Zeus, either by Leda or by Nemesis, and sister of the Dioscuri. As a young girl, she was carried off by Theseus, but she was rescued by her brothers. She was also the

  • Helen of Troy (ballet by Fokine and Lichine)

    Michel Fokine: …his last ballet, a comedy, Helen of Troy, for the American Ballet Theatre shortly before his death. It was completed by David Lichine and was premiered at Mexico City on Sept. 10, 1942. His wife, the dancer Vera Fokina, who had performed in many of his ballets, survived him until…

  • Helen of Troy (film by Wise [1956])

    Robert Wise: Films of the 1950s: Helen of Troy (1956) is notable only for an early appearance by French actress Brigitte Bardot. This Could Be the Night and Until They Sail (both 1957) starred Jean Simmons in a comedy and a drama, respectively. More interesting were the western Tribute to a…

  • Helen’s War: Portrait of a Dissident (film by Broinowski [2004])

    Helen Caldicott: …the subject of the documentary Helen’s War: Portrait of a Dissident (2004), which was made by Anna Broinowski, her niece.

  • Helen, Saint (Roman empress)

    St. Helena, ; Western feast day August 18; Eastern feast day [with Constantine] May 21), Roman empress who was the reputed discoverer of Christ’s cross. (See also True Cross.) Helena was married to the Roman emperor Constantius I Chlorus, who renounced her for political reasons. When her son

  • Helena (queen of Adiabene)

    Adiabene: …embraced Judaism; the queen mother Helena (d. ad 50), famous for her generosity to the Jews and the Temple, and her sons Monobazus II and Izates II were buried in the Tombs of the Kings at Jerusalem. Adiabene was frequently attacked by the Romans during their campaigns against the Parthians.

  • Helena (Chinese empress dowager)

    Zhu Youlang: …fighting, the empress dowager, baptized Helena, sent a letter to Pope Innocent X asking for his prayers for the Ming cause. By the time the Vatican’s reply arrived several years later, Zhu and Helena were dead.

  • Helena (Arkansas, United States)

    Helena, city, seat (1830) of Phillips county, eastern Arkansas, U.S., port of the Mississippi River, about 50 miles (80 km) southwest of Memphis, Tennessee, and adjacent to the city of West Helena. The community, originally settled in 1797 and first called Monticello and then St. Francis, grew

  • Helena (work by Waugh)

    Evelyn Waugh: ) Helena, published in 1950, is a novel about the mother of Constantine the Great, in which Waugh re-created one moment in Christian history to assert a particular theological point. In a trilogy—Men at Arms (1952), Officers and Gentlemen (1955), and Unconditional Surrender (1961)—he analyzed the…

  • Helena (Montana, United States)

    Helena, city and capital of Montana, U.S., seat (1867) of Lewis and Clark county. The city is situated near the Missouri River, at the eastern foot of the Continental Divide (elevation 3,955 feet [1,205 metres]), in Prickly Pear Valley, a fertile region surrounded by rolling hills and lofty

  • Helena (fictional character, “A Midsummer Night’s Dream”)

    A Midsummer Night's Dream: Hoping to win Demetrius’s favour, Helena tells him their whereabouts and follows him to the forest, where he goes in search of Hermia. The forest is also full of fairies who have come for the duke’s wedding. Oberon, the king of the fairies, quarrels with his queen, Titania, and bids…

  • Helena Rubinstein, Inc. (American company)

    Helena Rubinstein: She founded Helena Rubinstein, Inc., a leading manufacturer and distributor of women’s cosmetics.

  • Helena, St. (Roman empress)

    St. Helena, ; Western feast day August 18; Eastern feast day [with Constantine] May 21), Roman empress who was the reputed discoverer of Christ’s cross. (See also True Cross.) Helena was married to the Roman emperor Constantius I Chlorus, who renounced her for political reasons. When her son

  • Helene (Greek mythology)

    Helen of Troy, in Greek legend, the most beautiful woman of Greece and the indirect cause of the Trojan War. She was daughter of Zeus, either by Leda or by Nemesis, and sister of the Dioscuri. As a young girl, she was carried off by Theseus, but she was rescued by her brothers. She was also the

  • Helene (moon of Saturn)

    Dione: …by two much smaller moons, Helene and Polydeuces (also named for Greek mythological figures). Helene, which has a diameter of about 30 km (20 miles), maintains a gravitationally stable position 60° ahead of Dione. Polydeuces has less than half the diameter of Helene and follows Dione by 60°, though with…

  • Helenē (play by Euripides)

    Helen, play by Euripides, performed in 412 bce. In this frankly light work, Euripides deflates one of the best-known legends of Greek mythology, that Helen ran off adulterously with Paris to Troy. In Euripides’ version, only a phantom Helen goes with Paris, and the real woman pines faithfully in

  • Helenium (plant)

    Sneezeweed, any of about 40 species of tall herbs constituting the genus Helenium of the family Asteraceae, native to North America. Most are perennials with flat-topped clusters of yellow, brown, or red flower heads and leaves that alternate along the stem. Summer- or fall-blooming species are

  • Helenus (Greek mythology)

    Helenus, in Greek legend, son of King Priam of Troy and his wife Hecuba, brother of Hector, and twin brother of the prophetess Cassandra. According to Homer he was a seer and warrior. After the death of Paris in the Trojan War, Helenus paid suit to Helen but when she rejected him for his brother,

  • Heleophrynidae (amphibian family)

    Anura: Annotated classification: Family Heleophrynidae No fossil record; 8 presacral vertebrae with cartilaginous intervertebral joints and a persistent notochord; larvae with large mouths lacking beaks; South Africa; 1 genus, 4 species; adult length 3.5–6.5 cm (1–3 inches). Family Hylidae (tree frogs) Miocene (23 million–5.3 million

  • Helfer, H. Lawrence (American astronomer)

    Milky Way Galaxy: Principal population types: In 1959 H. Lawrence Helfer, George Wallerstein, and Jesse L. Greenstein of the United States showed that the giant stars in globular clusters have chemical abundances quite different from those of Population I stars such as typified by the Sun. Population II stars have considerably lower abundances…

  • Helfrich, Conrad Emil Lambert (Dutch admiral)

    Conrad Emil Lambert Helfrich, Dutch admiral who during World War II commanded the ABDA (American, British, Dutch, and Australian) naval fleet in its unsuccessful attempt to protect the Dutch East Indies from Japanese attack. Between 1942 and 1944 he headed the Dutch armed forces in the southwestern

  • Helga pictures (works by Wyeth)

    Andrew Wyeth: …show of his so-called “Helga pictures,” organized by the National Gallery of Art in Washington, D.C., was also very popular, as was a 2006 retrospective at the Philadelphia Museum of Art. In 1990 he became the first artist to be awarded the Congressional Gold Medal, and in 2007 he…

  • Helga, Saint (Russian saint and regent)

    St. Olga, ; feast day July 11), princess who was the first recorded female ruler in Russia and the first member of the ruling family of Kiev to adopt Christianity. She was canonized as the first Russian saint of the Orthodox Church and is the patron saint of widows and converts. Olga was the widow

  • Helgason, Jón (Icelandic author)

    Icelandic literature: Poetry: …by Tómas Guðmundsson and by Jón Helgason. Steinn Steinarr (Aðalsteinn Kristmundsson), who was deeply influenced by Surrealism, experimented with abstract styles and spearheaded modernism in Icelandic poetry with his collection Ljóð (1937; “Poems”).

  • Helgaud (French historian)

    Helgaud, French Benedictine monk at the abbey of Fleury-sur-Loire whose major work, Epitoma vitae Roberti regis, is an artless, historically unreliable biography of the French king Robert II the Pious. Exhibiting more adulation than knowledge of the King, Helgaud related how Robert cured blind m

  • Helge (work by Oehlenschläger)

    Adam Gottlob Oehlenschläger: …of his most outstanding works, Helge (1814). Helge came to inspire both Swedish and Finnish national epic poems, by Esaias Tegnér (Frithiofs saga, 1825) and Johan Ludvig Runeberg (Kung Fjalar, 1844), respectively. His lyric poetry has in general outlived his dramatic verse. Oehlenschläger’s other significant later work is the poetic…

  • Helgeands Island (island, Stockholm, Sweden)

    Gamla Stan: It consists of Stads Island, Helgeands Island, and Riddar Island. Most of the buildings in this area date from the 16th and 17th centuries and are legally protected from renovation. Stads Island contains the Royal Palace; Storkyrkan, also called the Cathedral, or Church, of St. Nicolas; the German Church; the…

  • Helgeland, Brian (American writer, director, and producer)
  • Helgesen, Paul (Danish humanist)

    Paul Helgesen, Danish Humanist and champion of Scandinavian Roman Catholicism who opposed the Lutheran Reformation in Denmark. The author of several works against Scandinavian Reformers, he also translated works by the Dutch Humanist Erasmus and wrote the Skiby chronicle, a discussion of Danish

  • Helgoland (island, Germany)

    Helgoland, island, Schleswig-Holstein Land (state), northwestern Germany. It lies in the German Bay (Deutsche Bucht) of the North Sea, in the angle between the coast of Schleswig-Holstein and the estuaries of the Jade, Weser, and Elbe rivers, 40 miles (65 km) offshore northwest of Cuxhaven. The

  • Helgoland Bight, Battle of (European history)

    naval warfare: The age of steam and big gun: …battles in the North Sea: Helgoland Bight (August 28, 1914), Dogger Bank (January 24, 1915), and Jutland itself.

  • Helgoland-Zanzibar Treaty (Africa-Europe [1890])

    Zanzibar Treaty, (July 1, 1890), arrangement between Great Britain and Germany that defined their respective spheres of influence in eastern Africa and established German control of Helgoland, a North Sea island held by the British since 1814. The treaty was symptomatic of Germany’s desire for a

  • Helgolander Bay (bay, North Sea)

    gulf: Factors that affect the characteristics of gulfs: …occur at the heads of Helgoländer Bay in the North Sea and in the Gulf of Finland.

  • Heliaea (Athenian court)

    Greek law: …great political importance, the whole hēliaia (i.e., the popular assembly organized as a court of 6,001 men) was convened. Normally sections of the hēliaia (specifically called dikastēria), composed of 1,501, 1,001, or 501 men in criminal cases and 201 men in civil cases, were charged with the decision.

  • hēliaia (Athenian court)

    Greek law: …great political importance, the whole hēliaia (i.e., the popular assembly organized as a court of 6,001 men) was convened. Normally sections of the hēliaia (specifically called dikastēria), composed of 1,501, 1,001, or 501 men in criminal cases and 201 men in civil cases, were charged with the decision.

  • Heliamphora (plant)

    carnivorous plant: Major families: The sun pitchers, also known as marsh pitcher plants (genus Heliamphora), are native to a limited region in South America and consist of about 23 species. The cobra plant (Darlingtonia californica) is the only member of its genus and is indigenous to northern California and southern…

  • Heliand (Old Saxon epic)

    Heliand, (Old Saxon: “Saviour”) epic on the life of Christ in Old Saxon alliterative verse dating from about 830. It attempted to make the newly imposed Christian religion intelligible to the Saxons. Christ was made a Germanic king who rewarded his retainers (the disciples) with arm rings; Herod’s

  • Helianthemum (plant)

    Sun rose, any of 80–110 species of low-growing flowering plants making up the genus Helianthemum in the rock rose family (Cistaceae), the flowers of which resemble single roses. They include several sunny garden varieties, which are useful in rock gardens and wild gardens. H. apenninum, H.

  • Helianthus (plant)

    Sunflower, (genus Helianthus), genus of nearly 70 species of herbaceous plants of the aster family (Asteraceae). Sunflowers are native primarily to North and South America, and some species are cultivated as ornamentals for their spectacular size and flower heads and for their edible seeds. The

  • Helianthus annuus (plant)

    angiosperm: Inflorescences: , sunflowers, Helianthus annuus), for instance, the outer (or ray) flowers have a well-developed zygomorphic corolla, and the inner (disk) flowers have a small actinomorphic corolla. The inner disk flowers generally are complete flowers, and the ray flowers generally are sterile.

  • Helianthus tuberosus (plant)

    Jerusalem artichoke, (Helianthus tuberosus), sunflower species (Asteraceae family) native to North America and noted for its edible tubers. Jerusalem artichoke is popular as a cooked vegetable in Europe and has long been cultivated in France as a stock feed. In the United States it is rarely

  • Heliaster (echinoderm genus)

    sea star: Heliaster, a broad-disked, short-rayed genus of the western coast of Central America, may have as many as 50.

  • Helicacea (gastropod superfamily)

    gastropod: Classification: Superfamily Helicacea Land snails without (Oreohelicidae and Camaenidae) or with (Bradybaenidae, Helminthoglyptidae, and Helicidae) accessory glands on the genitalia; dominant land snails in most regions, including the edible snails of Europe (Helicidae).

  • helical spring (machine component)

    spring: The helical spring, in which wire is wrapped in a coil that resembles a screw thread, is probably the most commonly used mechanical spring. It can be designed to carry, pull, or push loads. Twisted helical (torsion) springs are used in engine starters and hinges. Helical…

  • helical unit (electronics)

    video tape recorder: …transverse, or quad, and the helical.

  • helicase (enzyme)

    heredity: DNA replication: Enzymes called helicases then separate the two strands of the double helix, exposing two template surfaces for the alignment of free nucleotides. Beginning at the origin of replication, a complex enzyme called DNA polymerase moves along the DNA molecule, pairing nucleotides on each template strand with free…

  • Helice (constellation)

    Ursa Major, (Latin: “Greater Bear”) in astronomy, a constellation of the northern sky, at about 10 hours 40 minutes right ascension and 56° north declination. It was referred to in the Old Testament (Job 9:9; 38:32) and mentioned by Homer in the Iliad (xviii, 487). The Greeks identified this

  • Helichrysum (plant)

    everlasting: …especially the true everlastings, or immortelles, species of the genus Helichrysum. Helichrysum—native to North Africa, Crete, and the parts of Asia bordering on the Mediterranean—is cultivated in many parts of Europe. The immortelles have one or more whorls of dry, scalelike or membranous bracts (leaves borne below flowers) that preserve…

  • Helicidae (gastropod family)

    gastropod: Classification: Helicidae) accessory glands on the genitalia; dominant land snails in most regions, including the edible snails of Europe (Helicidae). Assorted Referencesannotated classificationsDevonian

  • Helicinidae (gastropod family)

    gastropod: Classification: …and New World tropics (Helicinidae). Order Monotocardia Heart with 1 auricle; 1 gill, often modified; siphon and chemoreception osphradium (sensory receptor) progressively more complex; penis present; head frequently modified into a proboscis; nervous system progressively more concentrated; about 30,000 species. Suborder

  • Helicobacter pylori (bacterium)

    digestive system disease: Gastritis: Infection by the bacteria H. pylori is also a common cause of chronic gastritis. This usually responds to the withdrawal of the offending drugs and treatment with the same agents used to treat peptic ulcers of the stomach and duodenum.

  • Helicobasidiales (order of fungi)

    fungus: Annotated classification: Order Helicobasidiales Mycoparasitic; violet-coloured mycelia release powdery conidia when emerging; example genera include Helicobasidium and Tuberculina. Order Platygloeales Parasitic on mosses and other plants; pycnium (fruiting body of rusts) forms masses of hyphae inside mosses; example genera include Platygloea and

  • helicoid cyme (plant anatomy)

    angiosperm: Inflorescences: …a one-sided cyme called a helicoid cyme (see photograph). A cymose inflorescence arranged in pairs at the nodes, in the manner of a false whorl, is called a verticillaster (see photograph). Finally, there are mixed inflorescences, as, for instance, the cymose clusters arranged in a racemose manner (e.g., lilac, Syringa…

  • Helicolenus (fish genus)

    scorpaeniform: Reproduction: The sebastine rosefishes (Helicolenus), found in both the northern Atlantic and Pacific oceans, have morphological affinities with the subfamily Scorpaeninae. Studies of their reproductive biology have shown that the sebastine rosefishes have intraovarian embryos embedded in a gelatinous matrix, and they thus appear to combine sebastine viviparity with…

  • helicon (musical instrument)

    Helicon, a large, valved bass brass instrument that is a member of the tuba family. Developed in 1845 by Ignaz Stowasser of Vienna, it has a spiral circular form that allows the helicon’s bell (the flared end of the instrument) to rest on the player’s left shoulder and, thus, makes the instrument

  • Helicon Hall (American cooperative)
  • helicon wave (physics)

    plasma: Higher frequency waves: …these two waves (called the electron cyclotron and ion cyclotron waves, respectively) cause electron and cyclotron resonances (synchronization) at the appropriate resonance frequencies. Beyond these resonances, transverse wave propagation does not occur at all until frequencies comparable to and above the plasma frequency are reached.

  • Helicon, Mount (mountain, Greece)

    Mount Helicon, mountain of the Helicon range in Boeotia (Modern Greek: Voiotía), Greece, between Límni (lake) Kopaḯs and the Gulf of Corinth (Korinthiakós). A continuation of the Parnassus (Parnassós) range, which rises to about 8,000 ft (2,400 m), the Helicon range reaches only about 5,000 ft. The

  • Heliconia (plant genus)

    Heliconia, the only genus of the family Heliconiaceae, with 100–200 species in tropical America and the western Pacific. The large perennial herbs have brightly coloured bracts (leaf-shaped structures) and bear numerous flowers. The fruit is usually blue. These attractive plants have stout or

  • Heliconia psittacorum (plant)

    Heliconia: One colourful species, H. psittacorum, named for its resemblance to a parrot’s plumage, has greenish yellow flowers with black spots near the tips and red bracts.

  • Helicoplacoidea (fossil echinoderm class)

    echinoderm: Annotated classification: †Class Helicoplacoidea Lower Cambrian about 570,000,000 years ago; pear-shaped or spindle-shaped body with many plates arranged spirally. †Class Ophiocistioidea Lower Ordovician to Upper Silurian about 395,000,000–500,000,000 years ago; dome-shaped body partly or completely covered by well-developed test; 5 ambulacral tracts carry plated tube feet

  • helicopter (aircraft)

    Helicopter, aircraft with one or more power-driven horizontal propellers or rotors that enable it to take off and land vertically, to move in any direction, or to remain stationary in the air. Other vertical-flight craft include autogiros, convertiplanes, and V/STOL aircraft of a number of

  • Helicosporidium (protozoan genus)

    Helicosporidium, protozoan parasite genus found in insects. It is the only genus of the cnidosporidian phylum Myxozoa (Myxosporidia). The young live in the body cavity, fat, or nervous tissue of the host insect. The life cycle, which is not fully known, includes a sexual period of multiple

  • Helicostomella subulata (protozoan)

    protozoan: Adaptations: Helicostomella subulata, for example, excysts in June in temperate waters and becomes numerous from July through October. It encysts again in October, sinking to the sediments, where it remains until the following year. The cyst is a normal part of the annual life cycle, and…

  • helicotrema (anatomy)

    human ear: Structure of the cochlea: …of the cochlea, called the helicotrema, which can be seen if the cochlea is sliced longitudinally down the middle. At its basal end, near the middle ear, the scala vestibuli opens into the vestibule. The basal end of the scala tympani ends blindly just below the round window. Nearby is…

  • helictite (geology)

    Helictite, cave deposit that has a branching, curved, or spiralled shape and may grow in any direction in seeming defiance of gravity. A helictite begins as a soda-straw-like tube formed as individual drops of water deposit calcium carbonate around the rim. The drops do not fall as in stalactite

  • Helictotrichon (plant genus)

    grassland: Biota: …fescue prairie with Festuca and Helictotrichon; in the west, to a short-grass steppe dominated by Bouteloua gracilis and Buchloe dactyloides; and to the east, to a tall-grass prairie with the bluestem grasses Andropogon gerardii and A. scoparium. Trees and shrubs were generally absent, but a large variety of herbaceous plants…

  • Helie, Paulus (Danish humanist)

    Paul Helgesen, Danish Humanist and champion of Scandinavian Roman Catholicism who opposed the Lutheran Reformation in Denmark. The author of several works against Scandinavian Reformers, he also translated works by the Dutch Humanist Erasmus and wrote the Skiby chronicle, a discussion of Danish

  • Heligang (China)

    Hegang, city, eastern Heilongjiang sheng (province), northeastern China. It is a prefecture-level municipality (shi) situated in the southeastern section of the Xiao Hinggan (Lesser Khingan) Range and is one of the principal coal-producing cities in China. The Hegang mines were founded in 1916 by a

  • Heligoland (island, Germany)

    Helgoland, island, Schleswig-Holstein Land (state), northwestern Germany. It lies in the German Bay (Deutsche Bucht) of the North Sea, in the angle between the coast of Schleswig-Holstein and the estuaries of the Jade, Weser, and Elbe rivers, 40 miles (65 km) offshore northwest of Cuxhaven. The

  • Heligoland, Battle of (European history [1864])

    Battle of Heligoland, (9 May 1864), naval engagement of the Second Schleswig War (see German-Danish War), pitting the Danes against a joint Prussian-Austrian force. Although a relatively small action, the battle provided the Danes with their greatest success in the war. It could not change the

  • heliocentric system (astronomy)

    Heliocentrism, a cosmological model in which the Sun is assumed to lie at or near a central point (e.g., of the solar system or of the universe) while the Earth and other bodies revolve around it. In the 5th century bc the Greek philosophers Philolaus and Hicetas speculated separately that the

  • heliocentric theory (astronomy)

    Heliocentrism, a cosmological model in which the Sun is assumed to lie at or near a central point (e.g., of the solar system or of the universe) while the Earth and other bodies revolve around it. In the 5th century bc the Greek philosophers Philolaus and Hicetas speculated separately that the

  • heliocentrism (astronomy)

    Heliocentrism, a cosmological model in which the Sun is assumed to lie at or near a central point (e.g., of the solar system or of the universe) while the Earth and other bodies revolve around it. In the 5th century bc the Greek philosophers Philolaus and Hicetas speculated separately that the

  • Heliodorus (Seleucid official)

    Antiochus IV Epiphanes: Early career: …after Seleucus was murdered by Heliodorus, a usurper, Antiochus in turn ousted him. During this period of uncertainty in Syria, the guardians of Ptolemy VI, the Egyptian ruler, laid claim to Coele Syria, Palestine, and Phoenicia, which Antiochus III had conquered. Both the Syrian and Egyptian parties appealed to Rome…

  • Heliodorus of Emesa (Greek writer)

    Heliodorus of Emesa, Greek writer, author of the Aethiopica, the longest and most readable of the extant ancient Greek novels. The Aethiopica tells the story of an Ethiopian princess and a Thessalian prince who undergo a series of perils (battles, voyages, piracy, abductions, robbery, and torture)

  • heliodromus (Mithraism)

    mystery religion: Rites and festivals: Leo (Lion), Perses (Persian), Heliodromus (Courier of the Sun), and Pater (Father). Those in the lowest ranks, certainly the Corax, were the servants of the community during the sacred meal of bread and water that formed part of the rite.

  • helioflagellate (protozoan)

    Helioflagellate, freshwater protozoan of the class Zoomastigophorea. Helioflagellates sometimes are considered relatives of the heliozoans (organisms having pseudopodia but no flagella) because of their slender radiating cytoplasmic masses called pseudopodia. The cores of the pseudopodia of some

  • Heliogabalus (Roman emperor)

    Elagabalus, Roman emperor from 218 to 222, notable chiefly for his eccentric behaviour. The family of his mother, Julia Soaemias, were hereditary high priests of the god Baal at Emesa (in ancient Syria), worshiped in that locality under the name Elah-Gabal (thus Elagabalus). The emperor Caracalla

  • heliograph (signaling device)

    military communication: The advent of electrical signaling: …through the development of the heliograph. It employed two adjustable mirrors so arranged that a beam of light from the sun could be reflected in any direction. The beam was interrupted by a key-operated shutter that permitted the formation of the dots and dashes of the Morse code. Where climatic…

  • heliography (photography)

    history of photography: Heliography: Nicéphore Niépce, an amateur inventor living near Chalon-sur-Saône, a city 189 miles (304 km) southeast of Paris, was interested in lithography, a process in which drawings are copied or drawn by hand onto lithographic stone and then printed in ink. Not artistically trained, Niépce…

  • heliogravure process (printing)

    Charles Nègre: …as a premier maker of heliogravures, reproductions of drawings or other graphic material with a photomechanical process invented by Nicéphore Niépce in 1822. He used the process to create plates for a monograph of his series of photographs of Chartres Cathedral under renovation. The book won the highest honours at…

  • heliometer (instrument)

    Heliometer, astronomical instrument often used to measure the Sun’s diameter and, more generally, angular distances on the sky The heliometer consists of a telescope in which the objective lens is cut along its diameter into two halves that can be moved independently. This produces two separate

  • helion (astronomy)

    celestial mechanics: Kepler’s laws of planetary motion: The term helion refers specifically to the Sun as the primary body about which the planet is orbiting. As the points P and A are also called apses, periapse and apoapse are often used to designate the corresponding points in an orbit about any primary body, although…

  • Hélion, Jean (French painter)

    Jean Hélion, French painter who was noted for his abstract paintings. Hélion initially studied engineering and architecture in Lille, France, and then went to Paris in 1921, where he became interested in painting. Until 1925 he supported himself by working for an architecture firm, while painting

  • Heliopais personata (bird)

    finfoot: The masked, or Asiatic, finfoot (Heliopais personata) is found in Central and Southeast Asia. The feet are bright green, and the sexes can be told apart by the colour of the iris: it is yellow in the female and brown in the male.

  • heliopause (astronomy)

    Heliopause, boundary of the heliosphere, the spherical region around the Sun that is filled with solar magnetic fields and the outward-moving solar wind consisting of protons and electrons. Nearer the Sun than the heliopause lies the heliosheath, a region of transition where the solar wind slows to

  • Heliophyllum (fossil coral genus)

    Heliophyllum, genus of extinct coral found as fossils in Devonian marine rocks (the Devonian Period began 416 million years ago and lasted about 56 million years). Heliophyllum was a solitary animal rather than a colonial form. The distinctive laminated form of its structure is clearly periodic,

  • Heliopolis (district, Cairo, Egypt)

    Cairo: City layout: Heliopolis, or Miṣr al-Jadīdah (“New Cairo”), became a major site of development in the 1970s and ’80s, witnessing significant population growth and commercial expansion. Since that time, urban developments have increasingly encroached upon agricultural land, extending into the desert periphery; Heliopolis and Naṣr City (a suburb begun…

  • Heliopolis (archaeological site, Lebanon)

    Baalbeck, large archaeological complex encompassing the ruins of an ancient Roman town in eastern Lebanon. It is located in the broad Al-Biqāʿ (Bekaa Valley) region, at an elevation of roughly 3,700 feet (1,130 metres) about 50 miles (80 km) east-northeast of Beirut. The complex was designated a

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