Encyclopædia Britannica Australia -

Encyclopedias since 1768

0-9

Helena ... helmet

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 ...
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 ...
Helena, Saint: Roman empress who was the reputed discoverer of Christ's cross.
Helenus: in Greek legend, son of King Priam of Troy and his wife Hecuba, brother of Hector, and twin of the prophetess Cassandra. According to Homer he was a seer and warrior. After the death of Paris in the Trojan War, ...
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.
Helgesen, Paul: 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 ...
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 ...
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 warlike Saxons. Christ was made a Germanic king who rewarded ...
helicon: a bass or contrabass tuba built in a spiral circular form and resting on the shoulder. It is believed to have been invented in Russia but was perfected in 1849 by Ignaz Stowasser in Vienna. The helicon is chiefly used ...
Helicon, Mount: mountain of the Helicon range in Boeotia, Greece, between Limni (lake) Kopai¨s and the Gulf of Corinth. A continuation of the Parnassus range, which rises to about 8,000 ft (2,400 m), the Helicon range reaches only about 5,000 ft. The ...
Heliconia: the only genus of the family Heliconiaceae, with approximately 120 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 bluish.
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 ...
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, ...
heliocentric system: 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 ...
Heliodorus Of Emesa: Greek writer from Emesa in Syria, author of the Aethiopica, the longest and most readable of the extant ancient Greek novels.
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 genera of helioflagellates radiate ...
Helion, Jean: French painter who was noted for his abstract paintings.
heliopause: boundary of the heliosphere, the teardrop-shaped region around the Sun that is filled with solar-magnetic fields and outward-moving solar gas consisting of protons and electrons. Outside the heliopause lies the heliosheath, a region of transition between the heliosphere and the ...
Heliopolis: one of the most ancient Egyptian cities, and the seat of worship of the sun god, Re. It was the capital of the 15th nome of Lower Egypt, but Heliopolis was important as a religious rather than a political centre. ...
Helios: (Greek: "Sun"), in Greek religion, the sun god. He drove a chariot daily from east to west across the sky and sailed around the northerly stream of Ocean each night in a huge cup. In classical Greece, Helios was especially ...
Helios: either of two unmanned solar probes developed by West Germany in cooperation with the U.S. National Aeronautics and Space Administration (NASA). Helios 1 and Helios 2 were launched by NASA from the John F. Kennedy Space Center in Cape Canaveral, ...
heliostat: instrument used in solar telescopes to orient and focus sunlight along a fixed direction. A typical heliostat consists of a flat plane mirror and a curved parabolic mirror. The plane mirror is mounted along an axis parallel (i.e., equatorial) to ...
heliotrope: any of about 250 species of tropical or temperate, mostly herbaceous plants that make up the genus Heliotropium (family Boraginaceae) and are distributed throughout the world. The genus has many weedy species. The best known is garden heliotrope (H. arborescens), ...
heliozoan: any member of the protozoan class Heliozoea (superclass Actinopoda). Heliozoans are spherical and predominantly freshwater and are found either floating or stalked. They are frequently enveloped by a shell (or test) composed of silica or organic material secreted by the ...
helium: chemical element, inert gas of Group 0 (noble gases) of the periodic table. The second lightest element (only hydrogen is lighter), helium is a colourless, odourless, and tasteless gas that becomes liquid at −268.9° C (−452° F). Only under increased ...
helium dating: method of age determination that depends on the production of helium during the decay of the radioactive isotopes uranium-235, uranium-238, and thorium-232. Because of this decay, the helium content of any mineral or rock capable of retaining helium will increase ...
hell: the abode or state of being of evil spirits or souls that are damned to postmortem punishment. Derived from an Anglo-Saxon word meaning "to conceal," or "to cover," the term hell originally designated the torrid regions of the underworld, though ...
Hell Creek Formation: division of Upper Cretaceous rocks in North America (the Cretaceous Period lasted from 114 to 66.4 million years ago). Named for exposures studied on Hell Creek, near Jordan, Mont., it occurs in eastern Montana and portions of North Dakota, South ...
Hellabrunn Zoo: zoological garden in Munich. The spacious, wooded, 70-ha (173-ac) grounds resemble the animals' natural habitats. Hellabrunn specializes in breeding species threatened with extinction, such as the Przewalski's horse, and back breeding to species already extinct, such as the aurochs, a ...
Helland-Hansen, Bjorn: Norwegian pioneer of modern oceanography whose studies of the physical structure and dynamics of the oceans were instrumental in transforming oceanography from a science that was mainly descriptive to one based on the principles of physics and chemistry.
Hellanicus Of Lesbos: Greek historian whose work marks an advance in the development of historiography. He lived for some time at the court of one of the kings of Macedonia and died at Perperene, in Asia Minor.
hellanodikai: in ancient Greece, Elean officials who served as judges of the Olympic Games and who became well known for enforcing laws of fairness. They also had the honour of presenting the crowns and palm branches to the champions. Selected from ...
Hellas: enormous impact basin in the southern hemisphere of Mars and the planet's largest recognizable impact feature. Centred at roughly 40° S, 290° W, Hellas measures about 7,000 km (4,400 miles) across, including the broad elevated ring surrounding the depression, and ...
hellbender: (Cryptobranchus alleganiensis), salamander belonging to the family Cryptobranchidae (order Caudata) found in the larger, swift-flowing streams of the Ohio River system and other streams in the eastern and central United States. The animal grows to about 63 cm (25 inches) ...
hellebore: member of either of two genera of poisonous herbaceous plants, Helleborus and Veratrum, some species of which are grown as garden ornamentals.
helleborine: any member of either of two similar genera of orchids (family Orchidaceae): Cephalanthera, with about 14 north-temperate species, and Epipactis, with about 24 species native to north-temperate areas, tropical Africa, and Mexico. Epipactis has small, stalked flowers borne drooping on ...
Hellen: in Greek mythology, king of Phthia (at the northern end of the Gulf of Euboea) and grandson of the god Prometheus; he was the eponymous ancestor of all true Greeks, called Hellenes in his honour. The Hellenes consisted of the ...
Hellenistic Age: in the eastern Mediterranean and Middle East, the period between the death of Alexander the Great in 323 BC to the conquest of Egypt by Rome in 30 BC. For some purposes the period is extended for a further three ...
Hellenistic religion: any of the various systems of beliefs and practices of eastern Mediterranean peoples from 300 BC to AD 300.
Hellenistic romance: adventure tale, usually with a quasi-historical setting, in which a virtuous heroine and her valiant lover are separated by innumerable obstacles of human wickedness and natural catastrophe but are finally reunited. A precursor of the modern novel, the Hellenistic romance ...
Hellens, Franz: Belgian writer who produced more than 120 works, including novels, plays, criticism, and volumes of poetry and short stories. He also played an important role in Belgian-French literary life between 1920 and 1955 as editor of several progressive magazines and ...
Heller, Joseph: American writer whose novel Catch-22 (1961) was one of the most significant works of protest literature to appear after World War II. The satirical novel was a popular success, and a film version appeared in 1970.
Heller, Robert: original name William Henry Palmer British-born magician who popularized conjuring in the United States. Trained as a musician, Heller turned to magic after he saw a performance by the French magician Robert-Houdin in 1848.
Heller, Yom Tov Lipmann ben Nathan ha-Levi: Bohemian Jewish rabbi and scholar who is best known for his commentary on the Mishna. His works also indicate that he had extensive knowledge of mathematics, the sciences, and other secular subjects.
hellhound: a dog represented in mythology (such as that of ancient Greece and Scandinavia) as standing guard in the underworld. In Greek mythology this was Cerberus, a three-headed, dragon-tailed dog.
Hellman, Lillian: American playwright and motion-picture screenwriter whose dramas forcefully attacked injustice, exploitation, and selfishness.
Hells Canyon: gorge of the Snake River in the United States, forming part of the Idaho-Oregon boundary, between the Seven Devils and Wallowa mountains. It has a total length of 125 miles (201 km), along 40 miles (64 km) of which it ...
Hellstrom, Gustaf: Swedish realist novelist, journalist, and literary critic.
Hellweg: plateau and historic corridor in North Rhine-Westphalia Land (state), western Germany. It extends east-west from Duisburg to Paderborn, parallel to the northern edge of the Sauerland, and is bounded by the Ruhr (south) and Lippe (north) rivers.
Helmand River: river in southwestern Afghanistan and eastern Iran, about 715 miles (1,150 km) long. Rising in the Baba Range in east-central Afghanistan, it flows southwestward across more than half the length of Afghanistan before flowing northward for a short distance through ...
helmet: defensive covering for the head, one of the most universal forms of armour. Helmets are usually thought of as military equipment, but they are also worn by firemen, miners, construction workers, riot and motorcycle police, gridiron-football and ice-hockey players, and ...