Imam Bondjol was a Minangkabau religious leader and a key member of the Padri faction in the religious Padri War, which divided the Minangkabau people of Sumatra in the 19th century. When in about 1803 three pilgrims inspired by the ideas of the puritan Wahhābī sect returned from Mecca and launched

John Frederick Peto was an American still-life painter who, though influenced by the style and subject matter of the better-known trompe l’oeil (“fool-the-eye”) still-life painter William Harnett, developed a distinctive mode of expression. Biographical information on Peto is meagre, and few of his

Sándor Petőfi was one of the greatest Hungarian poets and a revolutionary who symbolized the Hungarian desire for freedom. Petőfi had an eventful youth; he studied at eight different schools, joined for a short time a group of strolling players, and enlisted as a private soldier, but because of ill

Sándor Petőfi was one of the greatest Hungarian poets and a revolutionary who symbolized the Hungarian desire for freedom. Petőfi had an eventful youth; he studied at eight different schools, joined for a short time a group of strolling players, and enlisted as a private soldier, but because of ill

Egyptian art and architecture: Greco-Roman Egypt: …interesting is the tomb of Petosiris, high priest of Thoth in nearby Hermopolis Magna in the late 4th century bce. It is in the form of a small temple with a pillared portico, elaborate column capitals, and a large forecourt. In its mural decorations a strong Greek influence merges with…

Petoskey, resort city, seat (1902) of Emmet county, northwestern Lower Peninsula of Michigan, U.S. It is located on Little Traverse Bay of Lake Michigan, about 70 miles (110 km) northeast of Traverse City. Settled in 1852 and named for the Ottawa chief Pet-o-sega, it was the site of St. Francis

Peter Chelčický was a Czech religious and political writer, the foremost thinker of the 15th-century Czech Hussite Reformation movement. A member of the south Bohemian gentry, Chelčický was much influenced by the thought of the English heretic John Wycliffe and the martyred Czech Reformer Jan Hus.

Czechoslovak history: The Luxembourg dynasty: …of advisers, headed by Archbishop Petr of Aspelt, tried to uphold the royal authority. In the resulting conflict, a powerful aristocratic faction scored a decisive victory in 1318. Its leader, Jindřich of Lípa, virtually ruled over Bohemia until his death in 1329. Meanwhile, John found satisfaction in tournaments and military…

Petra, ancient city, center of an Arab kingdom in Hellenistic and Roman times, the ruins of which are in southwest Jordan. The city was built on a terrace, pierced from east to west by the Wadi Mūsā (the Valley of Moses)—one of the places where, according to tradition, the Israelite leader Moses

DESY: …DESY completed construction of the Positron-Electron Tandem Ring Accelerator (PETRA), a larger collider capable of reaching 19 GeV per beam. In 1979 experiments with PETRA yielded the first direct evidence for the existence of gluons, the messenger particles of the strong force that bind quarks together within protons and

Peter the Great Bay, inlet, Sea of Japan, northwestern Pacific Ocean, in the Maritime (Primorye) region of far eastern Russia. The bay extends for 115 miles (185 km) from the mouth of the Tumen River (on the Russian-Chinese border) northeast across to Cape Povorotny. The bay reaches inland for 55

heraldry: The reading of heraldry: …as the system of Sylvester Petra-Sancta, an Italian herald, it makes use of the following equivalents: argent is denoted by a plain field, or by dots or points, gules by perpendicular lines, azure by horizontal lines, vert by lines from dexter chief to sinister base, purpure by lines from sinister…

Phetracha was the king of the Tai kingdom of Ayutthaya, or Siam (ruled 1688–1703), whose policies reduced European trade and influence in the country and helped preserve its independence. Phetracha was the foster brother of King Narai, whose patronage helped him rise to become head of the Elephant

David Petraeus is a U.S. army general who was appointed by Pres. George W. Bush to head multinational forces in Iraq (2007–08) and who later served as commander in chief of Central Command (Centcom; 2008–10) and as commander of U.S. and NATO forces in Afghanistan (2010–11). He later was director of

David Petraeus is a U.S. army general who was appointed by Pres. George W. Bush to head multinational forces in Iraq (2007–08) and who later served as commander in chief of Central Command (Centcom; 2008–10) and as commander of U.S. and NATO forces in Afghanistan (2010–11). He later was director of

Harry Mark Petrakis was an American novelist and short-story writer whose exuberant and sensitive works deal with the lives of Greek immigrants in urban America. Petrakis, the son of an Eastern Orthodox priest, attended the University of Illinois (1940–41) and held a variety of jobs to support

Petralona skull, an ancient human cranium discovered in 1960 in a cave near Thessaloníki, northeastern Greece. The age of this skull has been difficult to establish. At first it was believed to be contemporary with Neanderthals, perhaps no older than 120,000 years. Some methods, however, indicate

Petrarch was an Italian scholar, poet, and humanist whose poems addressed to Laura, an idealized beloved, contributed to the Renaissance flowering of lyric poetry. Petrarch’s inquiring mind and love of Classical authors led him to travel, visiting men of learning and searching monastic libraries

Petrarch was an Italian scholar, poet, and humanist whose poems addressed to Laura, an idealized beloved, contributed to the Renaissance flowering of lyric poetry. Petrarch’s inquiring mind and love of Classical authors led him to travel, visiting men of learning and searching monastic libraries

Petrarch: Moral and literary evolution (1340–46) of Petrarch: …a common reading of the Secretum meum (1342–43). It is an autobiographical treatise consisting of three dialogues between Petrarch and St. Augustine in the presence of Truth. In it he maintains hope that, even amidst worldly preoccupations and error, even while absorbed in himself and his own affairs, a man…

conceit: The Petrarchan conceit, which was especially popular with Renaissance writers of sonnets, is a hyperbolic comparison most often made by a suffering lover of his beautiful mistress to some physical object—e.g., a tomb, the ocean, the sun. Edmund Spenser’s Epithalamion, for instance, characterizes the beloved’s eyes…

sonnet: …beloved, Laura—established and perfected the Petrarchan (or Italian) sonnet, which remains one of the two principal sonnet forms, as well as the one most widely used. The other major form is the English (or Shakespearean) sonnet.

Italian literature: Petrarch (1304–74): The literary phenomenon known as Petrarchism developed rapidly within the poet’s lifetime and continued to grow during the following three centuries, deeply influencing the literatures of Italy, Spain, France, and England. His followers did not merely imitate but accepted his practice of strict literary discipline and his forms, including his…

Fyodor Dostoyevsky: Political activity and arrest of Fyodor Dostoyevsky: …began to participate in the Petrashevsky Circle, a group of intellectuals who discussed utopian socialism. He eventually joined a related, secret group devoted to revolution and illegal propaganda. It appears that Dostoyevsky did not sympathize (as others did) with egalitarian communism and terrorism but was motivated by his strong disapproval…

Goffredo Petrassi was one of the most influential Italian composers of the 20th century. He is known for incorporating various avant-garde techniques into a highly personal style. Petrassi was born to a family of modest means. He studied voice for some time at the Schola Cantorum di San Salvatore

Wanganui, city (“district”) and port, southwestern North Island, New Zealand, near the mouth of the Wanganui River. The site lies within a tract bought by the New Zealand Company in 1840. The company established a settlement in 1841 and named it Petre. It was renamed in 1844, the present name

Sir Edward Petre, 2nd Baronet was an English Jesuit, favourite of King James II of Great Britain. Educated in France, he entered the Society of Jesus in 1652 and took orders in 1671, when he returned to England. In 1679 he succeeded to the family baronetcy and estates and was appointed vice

Verbenaceae: Outstanding among the 30 Petrea species, all tropical American, is a woody evergreen vine called purple wreath, or sandpaper vine (P. volubilis). It bears long, hanging clusters of violet-blue pansylike flowers and has oval leaves so rough as to be likened to sandpaper. The 220 species of the genus…

Verbenaceae: …a woody evergreen vine called purple wreath, or sandpaper vine (P. volubilis). It bears long, hanging clusters of violet-blue pansylike flowers and has oval leaves so rough as to be likened to sandpaper. The 220 species of the genus Lippia bear clusters of white, rose, or purplish flowers. L. canescens…

Nicolaus Copernicus: Publication of De revolutionibus of Nicolaus Copernicus: …top printer in the city, Johann Petreius, who had published a number of ancient and modern astrological works during the 1530s. It was not uncommon for authors to participate directly in the printing of their manuscripts, sometimes even living in the printer’s home. However, Rheticus was unable to remain and…

petrel, any of a number of seabirds of the order Procellariiformes, particularly certain members of the family Procellariidae, which also includes the fulmars and the shearwaters. Members of the family Hydrobatidae are increasingly called storm petrels; those of the Pelecanoididae are usually

Bavarian State Orchestra: Kirill Petrenko succeeded Nagano in 2013.

Oksana Baiul: …Zmiyvskaya and fellow figure skater Viktor Petrenko (1992 World and Olympic gold medalist), Baiul began to flourish. She won the World Championships in 1993.

Romanian literature: Between the wars: …as for a number of Cezar Petrescu’s novels and even some of Ion Minulescu’s poems. Hortensia Papadat-Bengescu’s trilogy of novels (Fecioarele despletite [1926; “Disheveled Virgins”], Concert din muzică de Bach [1927; “A Bach Concert”], and Drumul ascuns [1933; “The Hidden Way”]) is a document of changing lifestyles and urbanization, similar…

Nicolae Ceaușescu: In 1939 he married Elena Petrescu, a Communist activist. While in prison, Ceaușescu became a protégé of his cell mate, the Communist leader Gheorghe Gheorghiu-Dej, who would become the undisputed Communist leader of Romania beginning in 1952. Escaping prison in August 1944 shortly before the Soviet occupation of Romania,…

Elio Petri was an Italian motion-picture director and screenwriter. Petri’s formal education was limited; most of his formative experiences occurred on the streets, in his neighbourhood, and in the local cell of the Italian Communist Party, of which he was a militant member until 1956. That year,

Laurentius Petri was a Lutheran churchman, a leader of the Protestant Reformation in Sweden and the first Protestant archbishop of Uppsala (1531–73). His influence was very great, although he was less dynamic and forceful than his brother Olaus. The Swedish Bible of 1541, for which he was

Olaus Petri was a Lutheran churchman who, with his brother Laurentius, played a decisive role in the reformation of the Swedish church. He studied at Wittenberg (1516–18) and absorbed the reformed teaching of Martin Luther and Philipp Melanchthon. When Gustavus Vasa was crowned king in 1523, Olaus

Maroochydore: …Maroochy River was sighted by Andrew Petrie in 1862, and Petrie took the name for the river and the district from an Aboriginal word meaning “water where the black swan lives.” The town of Maroochydore, founded in 1900 as a port serving inland districts and for timber exports from the…

A Raisin in the Sun: The film was nominated for two Golden Globe Awards—for best actress for McNeil and best actor for

Sir Flinders Petrie was a British archaeologist and Egyptologist who made valuable contributions to the techniques and methods of field excavation and invented a sequence dating method that made possible the reconstruction of history from the remains of ancient cultures. He was knighted in 1923.

Sir Flinders Petrie was a British archaeologist and Egyptologist who made valuable contributions to the techniques and methods of field excavation and invented a sequence dating method that made possible the reconstruction of history from the remains of ancient cultures. He was knighted in 1923.

Santa Cruz: The northeast-central Petrified Forest National Monument (1954) covers nearly 14 square miles (35 square km). Los Glaciares National Park, which lies farther south and has an area of 1,722 square miles (4,459 square km), including Lake Argentino, was designated a UNESCO World Heritage site in 1981. In…

Petrified Forest National Park, desert area containing plant and animal fossils and archaeological sites in eastern Arizona, U.S., 19 miles (30 km) east of Holbrook. It was established as a national monument in 1906 and as a national park in 1962. The area within the park proper is 146 square miles

The Petrified Forest, American crime film, released in 1936, that established Humphrey Bogart as a major talent. Although cast in a supporting role, he earned much of the film’s acclaim for his portrayal of the gangster Duke Mantee. Leslie Howard played Alan Squier, a disillusioned intellectual and

The Petrified Forest, drama in two acts by Robert Sherwood, published and produced in 1935. This melodramatic Depression-era tale of frustrated lives and spiritual emptiness is set in a gas station and lunchroom along an Arizona highway. Gabby, the daughter of the station’s owner, is unhappy with

Eudora Welty: …of her most anthologized stories—“The Petrified Man” and “Why I Live at the P.O.” In 1942 her short novel The Robber Bridegroom was issued, and in 1946 her first full-length novel, Delta Wedding. Her later novels include The Ponder Heart (1954), Losing Battles (1970), and The Optimist’s Daughter (1972),…

petrified wood, fossil formed by the invasion of minerals into cavities between and within cells of natural wood, usually by silica (silicon dioxide, SiO2) or calcite (calcium carbonate, CaCO3). The petrified forests of the western United States are silicified wood, the tree tissues having been

Věra Čáslavská: Out of Hiding: …suspicious judging when Soviet gymnast Larissa Petrik tied with Vera for first place in that competition, and during the medal ceremony Čáslavská reportedly lowered her head and turned away when the Soviet anthem was played.

James C. Petrillo was an American labour leader who served as president of the American Federation of Musicians (AFM) from 1940 to 1958. Petrillo grew up on Chicago’s West Side and, after a brief period as a trumpet player and bandleader, became active in an independent musicians’ union and served

James C. Petrillo was an American labour leader who served as president of the American Federation of Musicians (AFM) from 1940 to 1958. Petrillo grew up on Chicago’s West Side and, after a brief period as a trumpet player and bandleader, became active in an independent musicians’ union and served

Petrine theory, the principle that asserts the theological legitimacy of the ministry and primacy of the pope, the leader of the Roman Catholic Church. According to this principle, the apostle Peter was the first pope, and his ministry was passed on to his successors as bishops of Rome. The Petrine

Petrine theory, the principle that asserts the theological legitimacy of the ministry and primacy of the pope, the leader of the Roman Catholic Church. According to this principle, the apostle Peter was the first pope, and his ministry was passed on to his successors as bishops of Rome. The Petrine

Petrine theory, the principle that asserts the theological legitimacy of the ministry and primacy of the pope, the leader of the Roman Catholic Church. According to this principle, the apostle Peter was the first pope, and his ministry was passed on to his successors as bishops of Rome. The Petrine

massage: …toward the heart; compression (petrissage), which includes kneading, squeezing, and friction and is useful in stretching scar tissue, muscles, and tendons so that movement is easier; and percussion (tapotement), in which the sides of the hands are used to strike the surface of the skin in rapid succession to…

Nicolás Maduro: Creation of the constituent assembly: a Bitcoin-like cryptocurrency, the petro, its value being linked to the price of one barrel of Venezuelan crude oil. Although Maduro claimed that the first-day sales of the petro totaled some $735 million, skeptics saw the digital currency’s creation as a desperate measure. Seeking to limit the opposition’s ability…

Gustavo Petro is a Colombian politician and former member of the Marxist guerrilla group 19th of April Movement (M-19) who in 2022 became the first leftist to serve as the president of Colombia. Likely of Italian or Roma heritage, Petro was born in Ciénaga de Oro, a small town in a cattle- and

Gustavo Petro is a Colombian politician and former member of the Marxist guerrilla group 19th of April Movement (M-19) who in 2022 became the first leftist to serve as the president of Colombia. Likely of Italian or Roma heritage, Petro was born in Ciénaga de Oro, a small town in a cattle- and

Canada: Domestic policies: …government created the integrated, crown-owned Petro-Canada in 1975.

Comodoro Rivadavia: …was founded in 1901 by Francisco Petrobelli, a businessman interested in establishing an Atlantic Ocean port to handle the products of Colonia Sarmiento, a farming centre 80 miles (130 km) west-northwest. The name honours Comodoro Martín Rivadavia (1852–1901) of the Argentine navy.

Petrobras, Brazilian oil and gas company that was founded in 1953 to engage in the exploration, production, refining, and transport of domestic petroleum and petroleum products. Originally a state-owned monopoly, Petrobras became majority-owned by the state but competes against other Brazilian

Petrobras scandal, Brazilian political corruption scandal beginning in 2014 that involved the indictment of dozens of high-level businesspeople and politicians as part of a widespread investigation alleging that many millions of dollars had been kicked back to officials of Petrobras, Brazil’s huge

PetroCaribe, energy initiative launched by Venezuelan Pres. Hugo Chávez in 2005 to supply Venezuelan crude oil to countries in the Caribbean region at discounted prices. Members of PetroCaribe include Antigua and Barbuda, The Bahamas, Belize, Cuba, Dominica, Dominican Republic, Grenada, Guatemala,

swallow: …flask-shaped mud nests, include the cliff swallow (P. pyrrhonota), the bird of San Juan Capistrano Mission, in California; as with other swallows, it has strong homing instincts.

petrochemical, in the strictest sense, any of a large group of chemicals (as distinct from fuels) derived from petroleum and natural gas and used for a variety of commercial purposes. The definition, however, has been broadened to include the whole range of aliphatic, aromatic, and naphthenic

elephant shrew: micus), and the four-toed elephant shrew (Petrodromus tetradactylus); those three genera are classified together in a subfamily separate from Rhynchocyon. Macroscelididae is the only family in the order Macroscelidea. There are eight extinct genera, some of which had teeth similar to antelopes’ and were probably herbivores. The evolutionary…

Peterhof, suburb of St. Petersburg, northwestern European Russia. It lies on the southern shore of the Gulf of Finland, 18 miles (29 km) southwest of the city of St. Petersburg Peter I (the Great) founded Peterhof in 1709 as a country estate. After visiting the French court in 1717, he decided to

Amazon Rainforest: …2016 the state oil company Petroecuador had begun to drill and extract petroleum from the park.

Petrofina SA, former Belgian petroleum conglomerate that was acquired in 1999 by Total, a French oil firm, to create Totalfina. The original company was organized in 1920 as the Compagnie Financière Belge des Pétroles (“Belgian Petroleum Finance Company”), with its initial interest in the

wallaby: …species of rock wallabies (Petrogale) live among rocks, usually near water. They are prettily coloured in shades of brown and gray and are distinguished by stripes, patches, or other markings. They are extremely agile on rocky terrain. The three species of nail-tailed wallabies (Onychogalea) are named for a horny…

Arie Poldervaart: …work includes investigations of the petrogenesis (composition, occurrence, and origin) of igneous and metamorphic rocks and Precambrian (older than 570,000,000 years) geology. He specialized in applying petrologic techniques to problems of Earth history. He edited Crust of the Earth (1955) and wrote Basalts (The Poldervaart Treatise on Rocks of Basaltic…

Arie Poldervaart: …work includes investigations of the petrogenesis (composition, occurrence, and origin) of igneous and metamorphic rocks and Precambrian (older than 570,000,000 years) geology. He specialized in applying petrologic techniques to problems of Earth history. He edited Crust of the Earth (1955) and wrote Basalts (The Poldervaart Treatise on Rocks of Basaltic…

pictography: …carved on rocks are called petroglyphs.) A pictograph that stands for an individual idea or meaning may be called an ideogram; if a pictograph stands for an individual word, it is called a logogram (q.v.). Pictographs are also used as memory aids. Various North American Indian tribes used pictographs both…

Petroglyph National Monument, archaeological site featuring some 25,000 prehistoric and historic petroglyphs (rock carvings), central New Mexico, U.S. It is situated on the west side of Albuquerque, near the Rio Grande. In addition to the petroglyphs, there are hundreds of archaeological sites

St. Petersburg, city and port, extreme northwestern Russia. A major historical and cultural centre and an important port, St. Petersburg lies about 400 miles (640 km) northwest of Moscow and only about 7° south of the Arctic Circle. It is the second largest city of Russia and one of the world’s

Kuzma Petrov-Vodkin: In his celebrated painting The Year 1918 in Petrograd, also known as the Petrograd Madonna (1920), the events of the revolution are treated as bloodless and humanitarian, as if they were somehow abstract. This form of idealization was characteristic of the mature works of Petrov-Vodkin, and it is evident…

St. Petersburg: Petrograd Side: Upstream of the bifurcation of the Neva is the Petrograd Side, where the great Peter-Paul Fortress faces the Strelka across the Malaya Neva. Founded in 1703, this fortification, the city’s first structure, initially had earthen walls, but these were soon replaced by stone…

Izvestiya: …as an organ of the Petrograd Soviet of Workers’ and Soldiers’ Deputies. After the October Revolution that year, control of Izvestiya passed from the Mensheviks and Socialist Revolutionaries into the hands of the Bolsheviks, and the paper’s main offices were moved to Moscow. Izvestiya grew rapidly to a circulation of…

ITAR-TASS, (Russian: “Information Telegraph Agency of Russia–Telegraph Agency of the Soviet Union”), Russian news agency formed in 1992 after the breakup of the Soviet Union in 1991. ITAR reports on domestic news, while TASS reports on world events, including news from the other countries of the

pictography: …on rocks are known as petrograms; those that are incised or carved on rocks are called petroglyphs.) A pictograph that stands for an individual idea or meaning may be called an ideogram; if a pictograph stands for an individual word, it is called a logogram (q.v.). Pictographs are also used…

Henry Clifton Sorby: …a new type of spectrum microscope for analyzing the light of organic pigments, especially minute bloodstains. His research on meteoric geology led to studies of iron and steel, and he concluded that steel is a crystallized igneous rock. His later studies included the origin of stratified rocks, weathering, and marine…

optical crystallography: The science of petrography is largely based on the study of the appearance of thin, transparent sections of rocks in a microscope fitted with polarizers. In the absence of external crystalline form, as with the minerals in a rock, a mineral often may be readily identified by the…

robin: Familiar in Australia is the scarlet robin (Petroica multicolor), a species 11 cm (4.5 inches) tall, marked with black, white, and bright scarlet.

passeriform: Annotated classification: Family Petroicidae (Australasian robins) Small thrushlike and chatlike songbirds, 11–22 cm (4.3–8.7 inches). Some flycatcher-like in habits, but also engage in wing and tail flicking. Drab brown to colourful (yellow and red) plumages. DNA revealed they are not related to similar species of Eurasia but instead part…

Shlisselburg, town, Leningrad oblast (region), northwestern European Russia. It is located on the Neva River where it flows out of Lake Ladoga, east of St. Petersburg city. Founded as Oreshek in 1323 by the republic of Novgorod, the town was captured in the early 17th century by the Swedes, who

gasoline, mixture of volatile, flammable liquid hydrocarbons derived from petroleum and used as fuel for internal-combustion engines. It is also used as a solvent for oils and fats. Originally a by-product of the petroleum industry (kerosene being the principal product), gasoline became the

Molotov cocktail, a crude bomb, typically consisting of a bottle filled with a flammable liquid and a wick that is ignited before throwing. It is named for Vyacheslav Molotov, the foreign minister of the Soviet Union during and after World War II, though Molotov was not its inventor. It is also

gasoline engine, any of a class of internal-combustion engines that generate power by burning a volatile liquid fuel (gasoline or a gasoline mixture such as ethanol) with ignition initiated by an electric spark. Gasoline engines can be built to meet the requirements of practically any conceivable

operations research: Model construction: …the cars stopping at urban automotive service stations located at intersections of two streets revealed that almost all came from four of the 16 possible routes through the intersection (four ways of entering times four ways of leaving). Examination of the percentage of cars in each route that stopped for…

Petrolândia, town, south-central Pernambuco estado (state), northeastern Brazil. It lies on the left (east) bank of the São Francisco River, at the borders of Bahia, Pernambuco, and Alagoas states. It was known as Jatobá until 1939 and as Itaparica from 1939 until 1943. Petrolândia is the western

petroleum jelly, translucent, yellowish to amber or white, unctuous substance having almost no odour or taste, derived from petroleum and used principally in medicine and pharmacy as a protective dressing and as a substitute for fats in ointments and cosmetics. It is also used in many types of

Petrobras, Brazilian oil and gas company that was founded in 1953 to engage in the exploration, production, refining, and transport of domestic petroleum and petroleum products. Originally a state-owned monopoly, Petrobras became majority-owned by the state but competes against other Brazilian

Petróleos de Venezuela, SA, state-owned Venezuelan company created through the nationalization of the petroleum industry on Jan. 1, 1976. It earns the largest share of Venezuela’s foreign exchange. Its headquarters are in Caracas. By 1971 Venezuela had begun to take steps to curb the influence of

Petróleos Mexicanos, state-owned Mexican company, a producer, refiner, and distributor of crude oil, natural gas, and petroleum products. It is one of the largest petroleum companies in the world. It has long been a major source of revenue for Mexico’s federal government, contributing as much as

petroleum, complex mixture of hydrocarbons that occur in Earth in liquid, gaseous, or solid form. A natural resource, petroleum is most often conceived of in its liquid form, commonly called crude oil, but, as a technical term, petroleum also refers to natural gas and the viscous or solid form

fat and oil processing: Processes: …especially the various grades of petroleum benzin (commonly known as petroleum ether, commercial hexane, or heptane). In large-scale operations, solvent extraction is a more economical means of recovering oil than is mechanical pressing. In the United States and increasingly in Europe, there are many instances of simple petroleum benzin extraction…

petroleum engineering, the branch of engineering that focuses on processes that allow the development and exploitation of crude oil and natural gas fields as well as the technical analysis, computer modeling, and forecasting of their future production performance. Petroleum engineering evolved from

OPEC, multinational organization that was established to coordinate the petroleum policies of its members and to provide member states with technical and economic aid. OPEC was established at a conference held in Baghdad September 10–14, 1960, and was formally constituted in January 1961 by five

shore fly: …interesting species is the carnivorous petroleum fly (Helaeomyia petrolei), which lives and breeds in pools of crude petroleum and feeds on trapped insects. At one time, Indians in the western United States gathered the aquatic larvae of shore flies for food.

geology: Oil and natural gas: …20th century, the consumption of petroleum products increased sharply. This led to a depletion of many existing oil fields, notably in the United States, and intensive efforts to find new deposits.