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Butuan

Dumaguete*

Dipolog, ^yCaga^ab^e Oro ..0zarais*->jw- h ZAMBOANGA , T /

PENINSULA toV

Zamboanga. M Apo*

Isabela* ^ 9,692 fl. Cap( _

TAWI-TAWI ° °* General Santos * San Agustin

ISLAND .#■ Tirtaca Point SARANGA 5,

ISLANDS

CELEBES SEA

ment. Filipinos are predominantly of Malay descent, frequently with Chinese and sometimes American or Spanish ancestry. Languages: Pilipino and English (both official); the other main groups are Cebuano, Ilocano, Hiligaynon, and Bicol. Religions: Christianity (pre¬ dominantly Roman Catholic; also Protestant, other Christians); also Islam. Currency: Philippine peso. The Philippines consist of about 7,100 islands and islets. The two principal islands are Luzon in the north and Mindanao in the south. The Visayan group is in the central Philippines, Mindoro is directly south of Luzon, and Palawan is isolated in the west. The topog-

Philips Electronics NV ► philosophical anthropology I 1489

raphy is varied; inactive volcanoes and mountain ranges are the main fea¬ tures of most of the larger islands. The country has a predominantly market economy based largely on agriculture, light industries, and ser¬ vices. The Philippines is a republic with two legislative houses; its chief of state and head of government is the president. First visited by Ferdi¬ nand Magellan in 1521, the islands were colonized by the Spanish, who retained control until the Philippines were ceded to the U.S. in 1898 fol¬ lowing the Spanish-American War. The Commonwealth of the Philippines was established in 1935 to prepare the country for political and economic independence, which was delayed by World War II and the invasion of Japanese troops. The islands were liberated by U.S. forces in 1944-45, and the Republic of the Philippines was proclaimed in 1946, with a gov¬ ernment patterned on that of the U.S. In 1965 Ferdinand Marcos was elected president. He declared martial law in 1972, which lasted until 1981. After 20 years of dictatorial rule, Marcos was driven from power in 1986. Corazon Aquino became president and instituted a period of democratic rule that continued with the elections of subsequent presidents. The government has tried to come to terms with Muslim independence fighters in the southern islands by establishing the Muslim Mindanao autonomous region in southwestern Mindanao and nearby islands.

Philips Electronics NV in full Royal Philips Electronics NV Dutch Koninklijke Philips Electronics NV Major Dutch manufac¬ turer of consumer electronics, household appliances, lightbulbs, and imag¬ ing equipment. It was founded by Dutch engineer Gerard Philips in 1891 to make incandescent lamps and incorporated in 1912 under the name NV Philips Gloeilampenfabrieken (Dutch: Philips Incandescent Light Works). Its strong research efforts were consolidated in 1914 in a separate orga¬ nization that became the Philips Research Laboratories. It began manu¬ facturing radios in the 1920s, and after World War II it marketed stereo equipment, televisions, and other products under such brand names as Philips, Magnavox, and Norelco. Philips helped create the compact disc, the cassette tape, and the videocassette recorder, and it is a leading sup¬ plier of diagnostic medical equipment. Renamed Philips Electronics NV in 1991, the firm has manufacturing and marketing subsidiaries through¬ out the world.

Philistine Member of a group of Aegean origin that settled on the south¬ ern coast of Palestine. The Philistines first settled the region during the 12th century bc, about the time the Israelites arrived. They lived in five cities (the Pentapolis) that together made up Philistia, from which the Greeks derived the name Palestine. They first fought the Israelites in the 11th century bc. In the 10th century bc they were defeated by the Isra¬ elite king David. They were later ruled by Assyria, Egypt, Babylonia, Per¬ sia, Greece, and Rome. The group appears prominently in the Old Testament—from which much of the information about them is derived— though they left no written records of their own. It is from these many and coloured biblical references that the term assumes its modern sig¬ nificance in the English language.

Phillips, Irna (b. July 1, 1901, Chicago, Ill., U.S.—d. Dec. 22, 1973, Chicago) U.S. radio producer and director. She worked as a teacher before turning to writing for radio and creating the first soap opera, Painted

Dreams (1930). Later known as “Queen of the Soaps,” she intro¬ duced techniques such as the organ bridge to give a smooth flow between scenes and the cliff-hanger ending to each episode. Her daytime radio serials included Today’s Chil¬ dren (1933-38, 1943-50); The Guid¬ ing Light (1937-56; television, 1952-); Road of Life (1937-59); and Women in White (1938-42, 1944- 48), the first hospital soap opera. She also created the television serials As the World Turns (1956) and Another World (1964).

Phillips, Wendell (b. Nov. 29, 1811, Boston, Mass., U.S.—d. Feb. 2, 1884, Boston) U.S. reformer and abolitionist. A wealthy graduate of Harvard Law School, he sacrificed social status and a prospective politi¬ cal career in order to join the antisla¬

Wendell Phillips

LIBRARY OF CONGRESS, WASHINGTON, D.C.

very movement. His reputation as an inspirational orator was established with his address at an abolitionist meeting in 1837 to protest the murder of Elijah Lovejoy. He became an associate of William Lloyd Garrison and lectured widely at meetings of the American Anti-Slavery Society, serving as its president from 1865 to 1870. He also advocated prohibition, woman suffrage, prison reform, regulation of corporations, and labour reform.

Phillips curve Graphic representation of the inverse relationship between the rate of unemployment and the rate of change in money wages. In 1958 A. W. Phillips plotted British unemployment rates and rates of change in money wages and found that when unemployment rates were low, employers were more likely to bid wages up to lure good employ¬ ees away from their competitors. He claimed that this was a stable rela¬ tionship. In the 1960s macroeconomists substituted the rate of price inflation for the rate of change in money wages and promulgated the curve as a tool of economic policy, arguing that the simultaneous achievement of low unemployment and low inflation was problematic. Monetarists, including Milton Friedman, claimed the relationship was not stable.

Philo Judaeus \'fi-lo-ju-'de-9s\ or Philo of Alexandria (b. 10-15 bc, Alexandria—d. ad 45-50, Alexandria) Greek-speaking Jewish phi¬ losopher. A leader of the Jewish community of Alexandria, he led a del¬ egation to the emperor Caligula c. ad 40 to ask that Jews not be forced to worship him. His writings provide the clearest view of this development of Judaism in the Diaspora. His philosophy was influenced by Plato, Aris¬ totle, the Neo-Pythagoreans, the Cynics, and Stoicism. In his view of God, Philo was original in insisting on an individual Providence able to sus¬ pend the laws of nature, in contrast to the prevailing Greek view of a universal Providence which is itself subject to the laws of nature. As the first to attempt to synthesize revealed faith and philosophic reason, he occupies a unique position in the history of philosophy. He is regarded as the most important representative of Hellenistic Judaism and a fore¬ runner of Christian theology.

philodendron V.fi-b-'den-drsnX Any of about 200 species of climbing herbaceous plants that make up the genus Philodendron in the arum fam¬ ily, native to the New World tropics. Some are popular indoor foliage plants in colder areas and landscape plants in warmer climates. The leaves are often large and smooth-edged to variously lobed and cut. The inflo¬ rescence is seldom produced indoors. Many forms are available in culti¬ vation, foremost among them the common heart-leaf ( Philodendron scandens oxycardium). Large varieties include the spade-leaf philoden¬ dron {P. domesticum or P. hastatum ), with triangular leaves up to 2 ft (60 cm) long, and the selloum philodendron (P selloum ), with deeply cut leaves up to 3 ft (1 m) long.

Philopoemen \ 1 fi-l3-'pe-m9n\ (b. c. 253, Megalopolis, Arcadia—d. 182 bc, Messene, Messenia) General of the Achaean League. Elected federal cavalry commander (c. 210) and general of the league (208-207, 206- 205, 201-200), he won victories against the Aetolians and the Spartans, using Macedonian armour and tactics. In his fourth generalship (193-192) he failed against the Spartans by sea but crushed their army on land. The Roman Flamininus stopped his capture of Sparta, but when the Spartan leader was assassinated Philopoemen added that state to the confedera¬ tion. He was captured when Messene rebelled and given poison.

philosophe \ 1 fe-b- , z6f\ Any of the literary men, scientists, and think¬ ers of 18th-century France who were united, in spite of divergent per¬ sonal views, in their conviction of the supremacy and efficacy of human reason. Inspired by the philosophy of Rene Descartes, the skepticism of the libertines (or freethinkers), and the popularization of science by Bernard de Fontenelle (1657-1757), they were dedicated to the advancement of science and secular thought and to the open-mindedness of the Enlight¬ enment. They included Voltaire, Montesquieu, Denis Diderot, Jean Le Rond d’ Alembert, and Jean-Jacques Rousseau. The philosophes compiled the Encyclopedie, one of the great intellectual achievements of the century.

philosophical anthropology Study of human nature conducted by the methods of philosophy. It is concerned with questions such as the sta¬ tus of human beings in the universe, the purpose or meaning of human life, and whether humanity can be made an object of systematic study. Among the most important works in philosophical anthropology are Man’s Place in the Universe (1928), by Max Scheler; The Levels of the Organic and Man (1928), by Helmuth Plessner; Being and Time (1929), by Martin Heidegger; DerMensch (1940), by Arnold Gehlen; and An Essay on Man (1944), by Ernst Cassirer.

1490 I philosophy ► Phoenix Islands

philosophy Critical examination of the rational grounds of our most fundamental beliefs and logical analysis of the basic concepts employed in the expression of such beliefs. Philosophy may also be defined as reflection on the varieties of human experience, or as the rational, methodical, and systematic consideration of the topics that are of great¬ est concern to humanity. Philosophical inquiry is a central element in the intellectual history of many civilizations. Difficulty in achieving a con¬ sensus about the definition of the discipline partly reflects the fact that philosophers have frequently come to it from different fields and have preferred to reflect on different areas of experience. All the world’s great religions have produced significant allied philosophical schools. Western philosophers such as Thomas Aquinas, George Berkeley, and Soren Kierkeg¬ aard regarded philosophy as a means of defending religion and dispelling the antireligious errors of materialism and rationalism. Pythagoras, Rene Descartes, and Bertrand Russell, among others, were primarily mathema¬ ticians whose views of reality and knowledge were influenced by math¬ ematics. Figures such as Thomas Hobbes, Jean-Jacques Rousseau, and John Stuart Mill were mainly concerned with political philosophy, whereas Socrates and Plato were occupied chiefly by questions in ethics. The Pre- Socratics, Francis Bacon, and Alfred North Whitehead, among many oth¬ ers, started from an interest in the physical composition of the natural world. Other philosophical fields include aesthetics, epistemology, logic, metaphysics, philosophy of mind, and philosophical anthropology. See also

ANALYTIC PHILOSOPHY; CONTINENTAL PHILOSOPHY; FEMINIST PHILOSOPHY; philosophy Of SCIENCE.

phlebitis \fli- , bi-tas\ Inflammation of the wall of a vein. Causes include nearby infection, trauma, surgery, and childbirth. The area over the vein is painful, swollen, red, and hot. A tender, cordlike mass may be felt under the skin. It usually occurs in surface veins in the lower leg and can be treated with pain relievers and bed rest, with mild exercise after inflam¬ mation subsides. Phlebitis can last for years; in such cases, irritation of the vein’s inner lining leads to blood-clot formation, a condition known as thrombophlebitis (see thrombosis). In deeper veins, this requires anti¬ coagulants to prevent embolisms.

phloem \'flo-,em\ or bast Plant tissues that conduct foods made in the leaves to all other parts of the plant. Phloem is composed of several types of specialized cells, including sieve-tube cells and phloem fibers. Sieve tubes (columns of sieve-tube cells), which have perforated areas in their walls, provide the main channels in which food substances travel. Phloem fibers are long, flexible cells that make up the soft fibers used commer¬ cially (e.g., flax and hemp).

phlox Any of about 65 species of plants (genus Phlox), belonging to the family Polemoniaceae, admired both in gardens and in the wilds for their clustered heads of flowers. All spe¬ cies but one are native to North America. Phlox is herbaceous, usu¬ ally with oval or linear leaves; it has heads of massed tubular flowers with five flaring lobes. A few species are woody, but most are herbaceous annuals or perennials. Sizes range from the 5-ft-high (1.5-m) summer phlox ( P paniculata) to the 18-in.- high (45-cm) woodland perennial blue phlox ( P divaricata) to the low- creeping, freely branching, ever¬ green moss pink, or creeping phlox (P. subulata).

Phnom Penh \p9-'n6m-'pen\ City (pop., 1999 est.: 938,000), capital of Cambodia, at the junction of the Sab River (a tributary of the Tonle Sap) with the Mekong River. Founded in 1434 as the capital of the Khmer king¬ dom, it was abandoned several times before being reestablished in 1865. It was a cultural centre, with many institutions of higher learning. When the Khmer Rouge came to power in Cambodia in 1975, they forced the city’s population into the countryside to work in the fields. The city was repopulated beginning in 1979, and its educational institutions began a difficult period of recovery from the virtual extermination of Cambodia’s educated class. Although the city is 180 mi (290 km) from the sea, it is a major port of the Mekong River valley; it is linked to the South China Sea via a channel of the Mekong delta in Vietnam.

phobia Extreme and irrational fear of a particular object, class of objects, or situation. A phobia is classified as a type of anxiety disorder (a neurosis), since anxiety is its chief symptom. Phobias are generally believed to result when fear produced by an original threatening situation (such as a near¬ drowning in childhood) is transferred to other similar situations (such as encounters with bodies of water), the original fear often being repressed or forgotten. Behaviour therapy can be helpful in overcoming phobias, the pho¬ bic person being gradually exposed to the anxiety-provoking object or situ¬ ation in a way that demonstrates that no threat really exists.

Phocaea \fo-'se-o\ Ancient city on the Aegean Sea, northernmost of the Ionian cities on the western coast of Asia Minor (now the Gulf of Izmir, Turkey). An important maritime state c. 1000-550 bc, it founded a num¬ ber of colonies, including Massilia (Marseille) in the western Mediterra¬ nean. It declined after the Persian conquest c. 545 bc. The modem town of Foga is located in an olive- and tobacco-growing region and attracts tourists to the ancient city’s ruins.

Phocis \'fo-sis\ Ancient territory, central Greece. It extended north from the Gulf of Corinth over the range of Mount Parnassus to the Locrian Mountains, which formed the northern frontier. Its chief towns were Elateia, Delphi, and Daulis. Mainly a pastoral region, its early history is obscure. Traditionally, the Phocians controlled the sanctuary and oracle at Delphi, but they lost control after a war with neighbouring Greek states c. 590 bc. Phocis was allied with Sparta in the Peloponnesian War (431- 404 bc) and was conquered by Philip II of Macedon in 346 bc.

phoebe \'fe-be\ Any of three species (family Tyrannidae, suborder Tyr- anni) of suboscine passerines with a habit of twitching their tail when perching. The eastern phoebe (, Sayornis phoebe ) of North America is 7.5 in. (18 cm) long, plain brownish gray above, and paler below. Its call is a brisk “fee-bee” uttered over and over. It makes a mossy nest, strength¬ ened with mud, on a ledge, often under a bridge. Say’s phoebe ( S . saya), a slightly larger bird with buff-hued underparts, occurs in open country in western North America. The black phoebe (S’, nigricans), occurring from the southwestern U.S. to Argentina, is dark above with a white belly.

Phoenicia \fi-'ne-sh9\ Ancient region, Middle East. Corresponding to modern Lebanon, with adjoining parts of Syria and Israel, its chief cities were Sidon, Tyre, and Berot (modern Beirut). The Phoenicians were notable merchants, traders, and colonizers (see Carthage) of the Mediterranean region in the 1st millennium bc. The area was conquered successively by the Assyrians, Babylonians, Persians, and Macedonians under Alexander the Great. In 64 bc it was incorporated into the Roman province of Syria.

Phoenician \fi-'ne-sh3n\ One of a people of ancient Phoenicia. They were merchants, traders, and colonizers who probably arrived from the Persian Gulf c. 3000 bc. By the 2nd millennium bc they had colonies in the Levant, North Africa, Anatolia, and Cyprus. They traded wood, cloth, dyes, embroideries, wine, and decorative objects; ivory and wood carv¬ ing became their specialties, and the work of Phoenician goldsmiths and metalsmiths was well known. Their alphabet became the basis of the Greek alphabet.

Phoenix \'fe-niks\ City (pop., 2000: 1,321,045), capital of Arizona, U.S. It is located on the Salt River. The river valley was occupied as early as ad 1300 by prehistoric Indians, now known as the Hohokam culture, who disappeared in the early 15th century. A village was founded on the site in 1867 and incorporated as a city in 1881. It became the territorial capi¬ tal in 1889 and state capital in 1912. There was widespread expansion after World War II, with the population quadrupling between 1950 and 1960. Phoenix occupies a semiarid valley surrounded by mountains and irrigated fields; its economy is based on farming, manufacturing, mining, and tourism.

phoenix In ancient Egypt and in classical antiquity, a fabulous bird associated with the worship of the sun. The Egyptian phoenix was said to be as large as an eagle, with brilliant scarlet and gold plumage and a melodious cry. Only one phoenix existed at a time, and it lived no less than 500 years. As its end approached, it built a nest of aromatic boughs and spices, set it on fire, and was consumed in the flames. From the pyre was born a new phoenix, which sealed its predecessor’s ashes in an egg of myrrh and flew to Heliopolis to deposit them on the altar of the sun god. The phoenix thus symbolized immortality. See also fenghuang.

Phoenix Islands Group of eight small coral atolls, Kiribati. Lying in the west-central Pacific Ocean 1,650 mi (2,650 km) southwest of Hawaii, the low, sandy atolls have a total land area of about 11 sq mi (28 sq km)

Moss pink (Phlox subulata)

RUSS KINNE-PHOTO RESEARCHERS/EB INC.

Phoenix Park murders ► phosphorus I 1491

and were discovered in the 19th century by U.S. whaling ships. Annexed by Britain in 1889, they were joined to the Gilbert and Ellice Islands in 1937. They became part of independent Kiribati in 1979. Kanton is the only inhabited atoll.

Phoenix Park murders (May 6, 1882) Assassination in Dublin of British officials. The newly arrived chief secretary of Ireland, Lord Fre¬ derick Cavendish, and his undersecretary, Thomas Burke, were walking in Dublin’s Phoenix Park when they were stabbed to death by members of the Invincibles, a radical Irish nationalist secret society. The murders caused a revulsion against terrorism and enabled Charles Stewart Parnell to subordinate the Irish National League to the more moderate Home Rule Party in Parliament.

phoneme Smallest unit of speech distinguishing one word (or word element) from another (e.g., the sound p in tap, which differentiates that word from tab and tag). The term is usually restricted to vowels and con¬ sonants, but some linguists include differences of pitch, stress, and rhythm. A phoneme may have variants, called allophones, that differ pho¬ netically without affecting meaning. Phonemes may be recorded with special symbols, such as those of the International Phonetic Alphabet. In transcription, linguists conventionally place symbols for phonemes between slash marks: /p/.

phonetics Study of speech sounds. It deals with their articulation (artic¬ ulatory phonetics), their acoustic properties (acoustic phonetics), and how they combine to make syllables, words, and sentences (linguistic phonet¬ ics). The first phoneticians were Indian scholars (c. 300 bc) who tried to preserve the pronunciation of Sanskrit holy texts. The Classical Greeks are credited as the first to base a writing system on a phonetic alphabet. Modern phonetics began with Alexander Melville Bell (1819-1905), whose Visible Speech (1867) introduced a system of precise notation for writing down speech sounds. In the 20th century linguists focused on developing a classification system that can permit comparison of all human speech sounds. Another concern of modern phonetics is the men¬ tal processes of speech perception.

phonics Vfa-niks\ Method of reading instruction that breaks language down into its simplest components. Children learn the sounds of indi¬ vidual letters first, then the sounds of letters in combination and in simple words. Simple reading exercises with a controlled vocabulary reinforce the process. Phonics-based instruction was challenged by proponents of “whole-language” instruction, a process in which children are introduced to whole words at a time, are taught using real literature rather than read¬ ing exercises, and are encouraged to keep journals in which “creative” spelling is permitted. A strong backlash against whole-language teaching polarized these two approaches to reading instruction. Many schools have since come to use a combination of the two techniques.

phonograph or record player Instrument for reproducing sounds. A phonograph record stores a copy of sound waves as a series of undu¬ lations in a wavy groove inscribed on its rotating surface by the record¬ ing stylus. When the record is played back, another stylus (needle) responds to the undulations, and its motions are then reconverted into sound. Its invention is generally credited to Thomas Alva Edison (1877). Stereophonic systems, with two separate channels of information in a single groove, became a commercial reality in 1958. All modern phono¬ graph systems had certain components in common: a turntable that rotated the record; a stylus that tracked a groove in the record; a pickup that con¬ verted the mechanical movements of the stylus into electrical impulses; an amplifier that intensified these electrical impulses; and a loudspeaker that converted the amplified signals back into sound. Phonographs and records were the chief means of reproducing recorded sound at home until the 1980s, when they were largely replaced by recorded cassettes (see tape recorder) and compact discs.

phonology \f9-'na-l3-je\ Study of sound patterns within languages. Diachronic (historical) phonology traces and analyzes changes in speech sounds and sound systems over time (e.g., the process by which sea and see, once pronounced with different vowel sounds, have come to be pro¬ nounced alike). Synchronic (descriptive) phonology investigates sound patterns at a single stage in a language’s development, to identify which ones can occur and in what position (in English, for example, nt and rk appear within or at the end of words but not at the beginning).

phonon \'fo-,nan\ In solid-state physics, a quantum of lattice vibrational energy. In analogy to a photon (a quantum of light), a phonon is viewed

as a wave packet with particlelike properties (see wave-particle duality). The way phonons behave determines or affects various properties of sol¬ ids. Thermal conductivity, for instance, is explained by phonon interac¬ tions. Phonons also provide the basis for understanding superconductivity in certain metals.

Phony War (1939—40) Early months of World War II, marked by no major hostilities. The term was coined by journalists to derisively describe the six-month period (October 1939-March 1940) during which no land operations were undertaken by the Allies or the Germans after the Ger¬ man conquest of Poland in September 1939.

phosgene Vfaz- jen\ or carbonyl chloride Vkar-bs-.nilV Colourless, highly toxic gas used in chemical warfare as well as in industrial processes including the making of dyestuffs and polyurethane resins. Either alone or in combination with chlorine, it was used against troops in World War I. It smells like musty hay. Inhalation causes severe lung injury several hours after exposure. First prepared in 1811, it is manufactured by the reaction of carbon monoxide and chlorine in the presence of a catalyst. Gaseous phosgene is usually stored and transported as a liquid under pressure in steel cylinders or as a solution in toluene. Mixed with water, it forms carbon dioxide and hydrochloric acid.

phosphate Any of numerous chemical compounds related to phospho¬ ric acid (H3PO4). Phosphate salts are inorganic compounds containing the phosphate ion (PO4 - ), the hydrogen phosphate ion (HPO4 - ), or the dihy¬ drogen phosphate ion (H2PO4), along with any cation. Phosphate esters are organic compounds in which the hydrogens of phosphoric acid are replaced by organic groups (e.g., methyl, ethyl, phenyl), with one of their carbon atoms bonding to an oxygen atom in the phosphate group. Nucleic acids and ATP both contain phosphate; bones and teeth contain calcium phosphate. Phosphate rock (mainly calcium phosphate) is one of the four most important basic chemical commodities. Phosphates were formerly used in detergents, which washed into rivers and lakes, causing water blooms of algae and bacteria (see eutrophication); such use is now gener¬ ally outlawed or regulated. Phosphates are still used in fertilizers, baking powder, and toothpaste.

phospholipid \,fas-fo-Ti-p3d\ or phosphatide Any member of a large class of fatlike organic compounds that in their molecular structure resemble the triglycerides, except for the replacement of a fatty acid with a PHOSPHATE-containing polar group. The polar end of the molecule is soluble in water (hydrophilic) and water solutions (including cytoplasm); the other, fatty-acid end is soluble in fats (hydrophobic). In a watery envi¬ ronment phospholipids naturally combine to form a two-layer structure (upid bilayer) with the fat-soluble ends sandwiched in the middle and the water-soluble ends sticking out. Such lipid bilayers are the structural basis of cell membranes. Phospholipids are the principal components of the mye¬ lin sheaths of neurons. Examples of phospholipids include lecithin, ceph- alins, phosphoinositides (in the brain), and cardiolipin (in the heart). See also DETERGENT.

phosphorescence Emission of light from a substance exposed to radiation and persisting as an afterglow after the exciting radiation has been removed. Unlike fluorescence, in which the absorbed light is emit¬ ted about 10 -8 second after excitation, in phosphorescence the extra energy absorbed is stored in metastable states and reemitted later. Phos¬ phorescence may last from about 10~ 3 second to days or even years. The term phosphorescence is often applied to luminescence of living organisms, as well.

phosphorite Vfas-for-.itV or phosphate rock Rock with a high con¬ centration of phosphates in nodular or compact masses. The phosphates may be derived from a variety of sources, including marine invertebrates that secrete shells of calcium phosphate and the bones and excrement of vertebrates. Typical phosphorite beds contain about 30% phosphorus pen- toxide (P 2 0 5 ) and constitute the primary source of raw materials for phos¬ phate fertilizers. Significant deposits in the U.S. include the Phosphoria Formation in Idaho and the Monterey Formation in California. Major deposits also occur in the Sechura Desert in Peru.

phosphorus Nonmetallic chemical element, chemical symbol P, atomic number 15. The ordinary allotrope, called white phosphorus, is a poison¬ ous, colourless, semitransparent, soft, waxy solid that glows in the dark (see phosphorescence) and combusts spontaneously in air, producing dense white fumes of the oxide P 4 0 10 ; it is used as a rodenticide and a military smokescreen. Heat or sunlight converts it to the red phosphorus allotrope,

1492 I Photian Schism ► photometry

a violet-red powder that does not phosphoresce or ignite spontaneously. Much less reactive and soluble than white phosphorus, it is used in manu¬ facturing other phosphorus compounds and in semiconductors, fertilizers, safety matches, and fireworks. Black phosphorus, made by heating the white form under pressure, is flaky like graphite. Phosphorus seldom occurs uncombined in nature. As the phosphate ion, it is abundant and widely distributed, in apatite, phosphorite, and many other minerals. Phos¬ phorus has valence 3 or 5 in compounds, which have many uses in indus¬ try. Phosphine (PH 3 ) is a chemical raw material and a doping agent (deliberately added impurity) for solid-state electronics components. Organic phosphorus compounds are used as plasticizers, gasoline addi¬ tives, insecticides (e.g., parathion), and nerve gases. In living organisms the role of phosphorus is essential; it is a component of DNA and RNA, ATP, and bone.

Photian Schism See Photian Schism

Photius \'fo-she-3s. Saint (b. c. 820, Constantinople—d. 10th century; feast day February 6) Patriarch of Constantinople (858-867, 877-886). A high-ranking civil servant, he was promoted swiftly through the ecclesi¬ astical orders to become patriarch after the deposition of Ignatius, an action that offended Pope Nicholas I. Photius added to the conflict by refusing to restore dioceses earlier transferred from the Roman to the Byzantine church. Angry that Nicholas would not recognize him, Photius excommunicated the pope (867), thus beginning the Photian Schism. Pho¬ tius was deposed the same year but restored in 877 after his successor died. He and Pope John VIII agreed to return Bulgaria to the Roman church but to allow Greek bishops to remain.

Photo-Realism Late 20th-century painting style based on photogra¬ phy, in which realistic scenes are rendered in meticulous detail. An off¬ shoot of Pop art, it became a trend in U.S. painting in the 1970s among artists fascinated by camera images. Though photographs had been used by 19th-century painters such as Eugene Delacroix as substitutes for real¬ ity, the Photo-Realists relied on the photograph itself, replicating it in large-scale detail as the reality on which to base an acrylic painting. Its subjects often included reflecting surfaces (chrome-plated diners, motor¬ cycles, glass-fronted buildings, etc.). Its awesome technical precision, brilliant colour schemes, and visual complexity earned the style wide popularity. Its most notable practitioners were Chuck Close, Don Eddy, Richard Estes, and Audrey Flack.

Photo-Secession Group of U.S. photographers influenced by the Pic- torialist movement. Founded in 1902 by Alfred Stieglitz, the Photo- Secession sought recognition of photography as an art to be judged on its own terms. It was akin to such groups as the Linked Ring in London, and its name reflected that of the Sezession movement in Austria and Germany. The group regularly showed its work at the Little Galleries of the Photo- Secession, also known as “291” (its address on Fifth Avenue in New York City), a gallery run by Stieglitz. While Stieglitz did not believe in retouch¬ ing or manipulating negatives or prints, others of the group, such as Edward Steichen, were adherents of the impressionistic soft-focus school and the new techniques. By 1910 many members of the group left due to different aesthetic visions. The record of the Photo-Secession is contained in the quarterly Camera Work (1903-17).

photocell or photoelectric cell or electric eye Solid-state device with a photosensitive cathode that emits electrons when illuminated and an anode for collecting the emitted electrons. Illumination excites elec¬ trons, which are attracted to the anode, producing current proportional to the intensity of the illumination. In a photovoltaic cell, light is used to produce voltage. In a photoconductive cell, light is used to regulate the flow of current. Photocells are used in control systems, where interrupt¬ ing a beam of light opens a circuit, actuating a relay that supplies power to a mechanism to bring about a desired operation, such as opening a door or setting off a burglar alarm. Photocells are also used in photometry and SPECTROSCOPY.

photochemical reaction Chemical reaction initiated by absorption of energy in the form of visible (light), ultraviolet, or infrared radiation. Pri¬ mary photochemical processes occur as an immediate result, and second¬ ary processes may follow. The most important example is photosynthesis. Vision depends on photochemical reactions that occur in the eye (see retina; rhodopsin). In photographic film and paper, light activates their sil¬ ver salts to a state that is easy to reduce to metallic silver grains during development. Bleaching of laundry, tanning of human skin, formation of Earth’s ozone layer, and many industrial reactions are also photochemi¬

cal. Certain air pollutants (see smog) become more reactive and form noxious compounds in photochemical reactions.

photocopier Device for producing copies of text or graphic material by the use of light, heat, chemicals, or electrostatic charge. Most modern copiers use a method called xerography.

photoelectric effect Phenomenon in which charged particles are released from a material when it absorbs radiant energy (see radiation). It is often thought of as the ejection of electrons from the surface of a metal plate when visible light falls on it. It can also occur if the radiation is in the wave¬ length range of ultraviolet radiation, X rays, or gamma rays. The emitting sur¬ face may be a solid, liquid, or gas, and the emitted particles may be electrons or ions. The effect was discovered in 1887 by Heinrich Hertz and explained by Albert Einstein in work for which he received the Nobel Prize.

photoengraving Any of several processes for producing printing plates by photographic means (see photography). In general, a plate coated with a photosensitive substance is exposed to an image, usually on film; the plate is then treated in various ways, depending on the printing pro¬ cess to be used. Photoengraving is particularly useful for reproducing photographs via the halftone process. See also offset printing.

photography Method of recording permanent images by the action of light projected by a lens in a camera onto a film or other light-sensitive material. It was developed in the 19th century through the artistic aspi¬ rations of two Frenchmen, Nicephore Niepce and Louis-Jacques-Mande Daguerre, whose combined discoveries led to the invention of the first commercially successful process, the daguerreotype (1837). In addition, two Englishmen, Thomas Wedgwood and William Henry Fox Talbot, pat¬ ented the negative-positive calotype process (1839) that became the fore¬ runner of modern photographic technique. Photography was initially used for portraiture and landscapes. In the 1850s and ’60s, Mathew B. Brady and Roger Fenton pioneered war photography and photojournalism. From its inception, two views of photography predominated: one approach held that the camera and its resulting images truthfully document the real world, while the other considered the camera simply to be a tool, much like a paintbrush, with which to create artistic statements. The latter notion, known as Pictorialism, held sway from the late 1860s through the first decade of the 20th century, as photographers manipulated their nega¬ tives and prints to create hazy, elaborately staged images that resembled paintings. By the 1920s and ’30s, a new, more realistic style of photog¬ raphy gained prominence, as photographers such as Paul Strand, Edward Weston, and Ansel Adams began to pursue sharply focused, detailed images. The Great Depression and two world wars inspired many pho¬ tographers, including Walker Evans and Dorothea Lange, to pursue docu¬ mentary, often socially conscious photography. Inspired by such work, many photojournalists, including Alfred Eisenstaedt and Margaret Bourke- White, also emerged during this period. In the second half of the 20th century, the urban social scene became a subject of much interest to pho¬ tographers, as did celebrity portraiture and fashion photography. At the turn of the 21st century, photographers took advantage of digital capa¬ bilities by experimenting with enormous formats and new manipulative techniques. As technological advances improve photographic equipment, materials, and techniques, the scope of photography continues to expand enormously. See also digital camera.

photolysis \fo-'ta-l3-s9s\ Breakdown of molecules into smaller units via absorption of light. Flash photolysis, an experimental technique developed by Manfred Eigen, Ronald George Weyford Norrish, and George Porter, studies short-lived chemical intermediates formed in many photochemical reactions. An intense, brief flash of light splits molecules into short-lived fragments, which are analyzed by spectrophotometry in a second, less intense flash.

photometry \fo-'ta-m3-tre\ Precision measurement of the brightness, colour, and spectrum of stars and other celestial objects to obtain data on their structure, temperature, and composition. About 130 bc Hipparchus used a system that divided the stars into six magnitudes, from brightest to faintest. Beginning in the 17th century, use of the telescope led to the dis¬ covery of many fainter stars, and the scale was extended. The use of pho¬ tographic and, since the 1940s, photoelectric equipment has vastly extended the sensitivity and wavelength range of astronomical photom¬ etry. The main (UBVRI) classification system uses wave bands in the ultraviolet, blue, visual, red, and infrared ranges. More elaborate systems can distinguish giant and dwarf stars, detect metals in stars, and deter¬ mine surface gravity.

photon ► Phraya Taksin I 1493

To Calvin cycle

or dark reaction

The light reaction of photosynthesis. The light reaction occurs in two photosystems (units of chlorophyll molecules). Light energy (indicated by wavy arrows) absorbed by photosystem II causes the formation of high-energy electrons, which are transferred along a series of acceptor molecules in an electron transport chain to photosystem I. Photosystem II obtains replacement elec¬ trons from water molecules, resulting in their split into hydrogen ions (H+) and oxygen atoms. The oxygen atoms combine to form molecular oxygen (0 2 ), which is released into the atmosphere. The hydrogen ions are released into the lumen. Additional hydrogen ions are pumped into the lumen by electron acceptor molecules. This creates a high concentration of ions inside the lumen. The flow of hydrogen ions back across the photosynthetic membrane provides the energy needed to drive the synthesis of the energy-rich molecule ATP. High-energy electrons released as photosystem I absorbs light energy are used to drive the syn¬ thesis of NADPH. Photosystem I obtains replacement electrons from the electron transport chain. ATP provides the energy and NADPH provides the hydrogen atoms needed to drive the subsequent photosynthetic dark reaction, or Calvin cycle.

photon or light quantum Minute energy packet of electromagnetic radiation. In 1900 Max Planck found that heat radiation is emitted and absorbed in distinct units, which he called quanta. In 1905 Albert Einstein explained the photoelectric effect, proposing the existence of discrete energy packets in light. The term photon came into use for these packets in 1926. The energies of photons range from high-energy gamma rays and X rays to low-energy infrared and radio waves, though all travel at the same speed, the speed of light. Photons have no electric charge or rest mass and are the carriers of the electromagnetic field.

photoperiodism Response by an animal or plant to changes in daily, seasonal, or yearly cycles of light and darkness. Among animals, sleep, migration, reproduction, and the changing of coats or plumage are regu¬ lated to some extent by day length. In the poultry industry, photoperio¬ dism is commonly induced by artificial lighing to maximize egg laying and body weight. Plant growth, seed setting, germination, flowering, and fruiting are also affected by day length. Other environmental factors that modify an organism’s responses include temperature and nutrition.

photoreception Biological responses to stimulation by light, most often referring to the mechanism of vision. In one-celled organisms such as the amoeba, the whole cell may be sensitive to light. Earthworms have photoreceptive cells scattered over their bodies to help orient themselves by comparison of light intensities in different directions. Most animals have localized photoreceptors of varying complexity. In humans, photo¬ reception relies on the chemical response of a light-sensitive pigment, rhodopsin, in photoreceptor cells in the retina of the eye. Stimulation of those cells results in a stimulus being conducted toward the nervous sys¬ tem. Humans, like other vertebrates, have two types of photosensitive cells, rod cells and cone cells. Rod cells are responsible for vision when there is little light; cone cells mediate daylight vision and colour. Photo¬ reception also refers to photosynthesis in plants. See also sense.

range from about 18,000 °F (10,000 °C) at the bottom to 8,000 °F (4,000 °C) at the top; its density is about 1/1,000 that of air at the surface of Earth. Sunspots are photospheric phenomena. The photosphere has a granular structure. Each grain (cell), a mass of hot gas several hundred miles in diameter, rises from inside the Sun, radiates energy, and sinks back within minutes to be replaced by others in a constantly changing pattern.

photosynthesis Process by which green plants and certain other organisms transform light into chemical energy. In green plants, light energy is captured by chloro¬ phyll in the chloroplasts of the leaves and used to convert water, carbon dioxide, and minerals into oxygen and energy-rich organic compounds (simple and complex sugars) that are the basis of both plant and animal life. Photosynthesis consists of a number of photochemical and enzy¬ matic reactions. It occurs in two stages. During the light-dependent stage (light reaction), chlorophyll absorbs light energy, which excites some electrons in the pigment mol¬ ecules to higher energy levels; these leave the chlorophyll and pass along a series of molecules, generating for¬ mation of NADPH (an enzyme) and high-energy ATP molecules. Oxy¬ gen, released as a by-product, passes into the atmosphere through pores in the leaves. NADPH and ATP drive the second stage, the dark reaction (or Calvin cycle, discovered by Melvin Calvin), which does not require light. During this stage glucose is generated using atmospheric carbon dioxide. Photosynthesis is crucial for maintaining life on Earth; if it ceased, there would soon be little food or other organic matter on the planet, and most types of organisms would disappear.

phototube See photocell

photovoltaic effect Process in which two dissimilar materials in close contact act as an electric cell when struck by light or other radiant energy. In crystals of certain elements, such as silicon and germanium, the electrons are usually not free to move from atom to atom. Light striking the crys¬ tal provides the energy needed to free electrons from their bound condi¬ tion. These electrons can cross the junction between two dissimilar crystals more easily in one direction than another, so one side of the junc¬ tion acquires a negative voltage with respect to the other. As long as light falls on the two materials, the photovoltaic battery can continue to pro¬ vide voltage and current. The current can be used to measure the bright¬ ness of the light or as a source of power, as in a solar cell.

Phrachomklao See Mongkut Phrachunlachomklao See Chulalongkorn Phramongkutklao See Vajiravudh

phratry \'fra-tre\ In ancient Greece, tribal subdivisions of households or families claiming a common kin relation. At the apex of each phratry were aristocratic clans that had certain hereditary rights, such as the right to hold priestly offices. Both phratries and clans were patrilineal. The Athenian phratry is well known. Every native Athenian male belonged to a phratry; they were concerned with such matters as legitimacy of descent and inheritance.

photosphere Visible surface of the Sun, about 250 mi (400 km) thick. Phraya Taksin See Taksin It emits most of the Sun’s light that reaches Earth directly. Temperatures

1494 I phrenology ► physics

phrenology \fri-'na-l3-je\ Study of the shape of the skull as an indication of mental abilities and character traits. Franz Joseph Gall stated the principle that each of the innate mental faculties is based in a specific brain region (“organ”), whose size reflects the faculty’s prominence in a person and is reflected by the skull’s surface. He examined the skulls of persons with par¬ ticular traits (including “criminal” traits) for a feature he could identify with it. His followers Johann Kaspar Spurzheim (1776-1832) and George Combe (1788-1858) divided the scalp into areas they labeled with traits such as combativeness, cautiousness, and form perception. Though popu¬ lar well into the 20th century, phrenology has been wholly discredited.

Phrygia Vfri-je-oN Ancient district, west-central Anatolia. It was named for a people whom the Greeks called Phryges and who dominated Ana¬ tolia between the Hittite collapse (12th century bc) and ascent of Lydia (7th century bc). The Phrygians were possibly of Thracian origin (see Thrace) and had their capital at Gordium. The kingdom of their legendary ruler, Midas, ended c. 700 bc with the invasion of the Cimmerians, who burned the capital. The Phrygians excelled in metalwork, wood carving, carpet making, and embroidery. Their religious cult of the Great Mother of the Gods was passed on to the Greeks. Excavations conducted since 1945 have uncovered carved stone tombs and shrines there.

Phumiphon Adunlayadet See Bhumibol Adulyadej

Phyfe \'fif\, Duncan orig. Duncan Fife (b. 1768, near Loch Fan- nich, Ross and Cromarty, Scot.—d.

Aug. 16, 1854, New York, N.Y.,

U.S.) Scottish-born U.S. furniture designer. His family settled in Albany, N.Y., c. 1784; there he became an apprentice cabinetmaker and eventually opened his own shop.

In 1792 he moved to New York City, where he changed the spelling of his name and became so successful that he employed 100 carvers and cabi¬ netmakers. He was one of the first Americans to use the factory method of manufacturing furniture success¬ fully. Though he did not originate a new furniture style, he interpreted fashionable European styles—

Sheraton, Regency, Directoire,

Empire —with such grace that he became a major exponent of Neo- classicism. His furniture, decorated with typical period ornaments such as harps and acanthus leaves, was generally of high-quality mahogany.

phyle Vf!-le\ Any of several tribes wm that formed the largest political subgroups in all Dorian and most Ionian

Greek city-states. Phylae were simultaneously kinship groups, corpora¬ tions with their own officials and priests, and local units for administra¬ tive and military purposes. Athens’s original four phylae were replaced 3 by 10 under a reorganization (508/507 bc) initiated by Cleisthenes; Spar¬

ta’s original three were supplanted by five in the 8th century bc.

phyllite Vfi-.lItX Fine-grained metamorphic rock formed by the recrystal¬ lization of fine-grained, parent sedimentary rocks, such as mudstones or shales. Phyllite has a marked tendency to split into sheets or slabs; it may have a sheen on its surfaces due to tiny plates of micas. Its grain size is larger than that of slate but smaller than that of schist.

phylloxera V.fi-.lak-'sir-o, fs-Tak-so-roX Any of numerous, chiefly North American, insect species (genus Phylloxera, order Homoptera), many of which are serious pests of plants. Phylloxera form galls on and can defoliate trees, especially hickory and pecan. See also grape phylloxera.

phylogenetic tree \,fi-lo-j3-'ne-tik\ Diagram showing the evolution¬ ary interrelations of a group of organisms that usually originated from a shared ancestral form. The ancestor is in the tree trunk; organisms that have arisen from it are placed at the ends of tree branches. The distance of one group from the other groups indicates the degree of relationship; that is, closely related groups are located on branches close to one another. Though phylogenetic trees are speculative, they provide a convenient method for studying phylogenetic relationships and evolution. See also phylogeny.

phytogeny \fi-'la-j3-ne\ History of the evolution of a species or group, especially lines of descent and relationships among broad groups. The fundamental proposition is that plants or animals of different species descended from common ancestors. Because the evidence for such rela¬ tionships is almost always incomplete, most judgments of phylogenicity are based on indirect evidence and cautious speculation. Modern tax¬ onomy, the science of classifying organisms, is based on phylogeny. Early taxonomic systems had no theoretical basis; organisms were grouped according to apparent similarity. Biologists who propose a phylogeny obtain evidence from the fields of paleontology, comparative anatomy, comparative embryology, biochemistry, and molecular biology. The data and conclusions of phylogeny indicate that today’s living creatures are the product of a historical process of evolution and that degrees of resem¬ blance within and between groups correspond to degrees of relationship by descent from common ancestors. See also phylogenetic tree.

physiatry See physical medicine and rehabilitation

physical anthropology Branch of anthropology concerned with the study of human evolution and human biological variation. Research on human evolution involves the discovery, analysis, and description of fos¬ silized human remains. Two key goals are the identification of differences between humans and their human and nonhuman ancestors, and the clari¬ fication of the biological emergence of humankind. A variety of quanti¬ tative methods are used, including the comparative analysis of genetic codes. Research on biological variation among contemporary humans once relied heavily on the concept of race, but today principles of genet¬ ics and the analysis of such factors as blood type have largely eliminated race as a scientific category.

physical chemistry Branch of chemistry concerned with interactions and transformations of materials. Unlike other branches, it deals with the principles of physics underlying all chemical interactions (e.g., gas laws), seeking to measure, correlate, and explain the quantitative aspects of reac¬ tions. Quantum mechanics has clarified much for physical chemistry by modeling the smallest particles ordinarily dealt with in the field, atoms and molecules, enabling theoretical chemists to use computers and sophis¬ ticated mathematical techniques to understand the chemical behaviour of matter. Chemical thermodynamics deals with the relationship between heat and other forms of chemical energy, kinetics with chemical reaction rates. Subdisciplines of physical chemistry include electrochemistry, pho¬ tochemistry (see photochemical reaction), surface chemistry, and catalysis.

physical education Training in physical fitness and in skills requir¬ ing or promoting it. In the U.S. it is required in most primary and sec¬ ondary schools. It generally includes calisthenics, gymnastics, various sports, and some study of health. College majors in physical education have been available since the early 20th century. Most teaching is done in gymnasiums, though outdoor sports are also emphasized.

physical medicine and rehabilitation or physiatry \,fiz-e-'a-tre\ or physical therapy or rehabilitation medicine

Medical specialty treating chronic disabilities through physical means to help patients return to a comfortable, productive life despite a medical problem. Its objectives are pain relief, functional improvement or main¬ tenance, training in essential activities, and functional testing of areas such as strength, mobility, breathing capacity, and coordination. Physical medi¬ cine may use diathermy, hydrotherapy, massage, exercise, and functional training. The last can mean learning to work with a guide dog or a pros¬ thesis or learning new ways to carry out everyday activities with a limb missing, sometimes by using assistive devices. Physician specialists head rehabilitation teams including a physical therapist, rehabilitation engineer, rehabilitation nurse, psychological counselor, and sometimes a respiratory or speech therapist. See also occupational therapy; orthopedics.

physics Science that deals with the structure of matter and the interac¬ tions between the fundamental constituents of the observable universe. Long called natural philosophy (from the Greek physikos ), physics is concerned with all aspects of nature, covering the behaviour of objects under the action of given forces and the nature and origin of gravitational, electromagnetic, and nuclear force fields. The goal of physics is to for¬ mulate comprehensive principles that bring together and explain all dis¬ cernible phenomena. See also aerodynamics; astrophysics; atomic physics; biophysics; mechanics; nuclear physics; particle physics; quantum mechanics;

SOLID-STATE PHYSICS; STATISTICAL MECHANICS.

physics, mathematical See mathematical physics

Mahogany side chair designed by Phyfe, 1807; in The Henry Francis du Pont Winterthur Museum, Delaware

COURTESY OF THE HENRY FRANCIS DU PONT WINTERTHUR MUSEUM, DELAWARE

physics ► Piazzetta I 1495

physics, philosophy of Philosophical investigation of the concepts, problems, and methods of physics and related sciences. The philosophy of physics traditionally has been concerned with clarifying the logical struc¬ ture, ontological commitments, and intertheoretic relations of fundamen¬ tal physical theories, including relativity, quantum mechanics, and statistical mechanics. The field also addresses various metaphysical and epistemo¬ logical aspects of problems encountered in the foundations of theoretical physics. Examples include the apparent “directed” nature of time, the meaning of probabilistic descriptions of the initial state of the universe in statistical mechanics, the measurement problem in quantum mechan¬ ics (the problem of stating in precise terms the conditions in which proba¬ bilistic as opposed to deterministic laws apply to the motion of an elementary particle), and the problem of reconciling quantum mechanics with special, and ultimately general, relativity. See also uncertainty prin¬ ciple; UNIFIED FIELD THEORY.

physiocrat Member of a school of economics, founded in 18th-century France, that held that government should not interfere with the operation of natural economic laws. Generally regarded as the first scientific school of economics, the physiocratic school (the name refers to the “rule of nature”) was founded by Francois Quesnay, who demonstrated the economic rela¬ tion between a workshop and a farm and asserted that the farm alone added to a nation’s wealth. Land and agriculture were therefore believed to be the source of all wealth. The physiocrats envisaged a society in which written law would be in harmony with NATURAL law. They pictured a predominantly agricultural society, attacking mercantilism for its emphasis on manufactur¬ ing and foreign trade and its mass of economic regulations. Quesnay’s dis¬ ciples included Victor Riqueti, count de Mirabeau, and Pierre Samuel du Pont de Nemours (1739-1817). The school was in decline by 1768, and after the dismissal of a sympathetic comptroller general in 1776 the leading physiocrats were exiled. Though many of their theories, notably their theory of wealth, were later demolished, their introduction of scientific method to economics had a permanent effect on the discipline.

physiological psychology Study of the physiological basis of behaviour. Traditional specializations in the field cover perception, moti¬ vation, emotion, learning, memory, cognition, or mental disorders. Also con¬ sidered are other physical factors that affect the nervous system, including heredity, metabolism, hormones, disease, drug ingestion, and diet. An experimental science, physiological psychology relies heavily on labora¬ tory research and quantitative data.

physiology \,fi-ze-'a-l9-je\ Study of the functioning of living organ¬ isms or their constituent tissues or cells. Physiology was usually consid¬ ered separately from anatomy until the development of high-powered microscopes made it clear that structure and function were inseparable at the cellular and molecular level. An understanding of biochemistry is fun¬ damental to physiology. Physiological processes are dynamic; cells change their function in response to changes in the composition of their local environment, and the organism responds to alterations in both its internal and external environment. Many physiological reactions are aimed at preserving a constant physical and chemical internal environ¬ ment (homeostasis). See also cytology.

phytoflagellate \ .fi-to-'fla-j s-lst\ Any of several protozoans that have flagella in addition to sharing many characteristics with typical algae, especially the pigment chlorophyll and various other pigments. Some spe¬ cies, though similar in form, lack chlorophyll. Phytoflagellates may obtain nutrients by photosynthesis, by absorption through the body surface, or by ingestion of food particles. Cryptomonads are among the more impor¬ tant phytoflagellates.

phytoplankton V.fi-to-'plaqk-tsnV Flora of freely floating, often minute organisms that drift with water currents. Like land vegetation, phytoplankton uses carbon dioxide, releases oxygen, and converts min¬ erals to a form animals can use. In fresh water, large numbers of green algae often colour lakes and ponds, and cyanobacteria may affect the taste of drinking water. Oceanic phytoplankton is the primary food source, directly or indirectly, of all sea organisms. Composed of groups with silica-containing skeletons, such as diatoms and dinoflagellates, phy¬ toplankton varies seasonally in amount, increasing in spring and fall with favourable light, temperature, and minerals.

pi In mathematics, the ratio of the circumference of a circle to its diameter. An irrational number (see also transcendental number), it has an approximate value of 3.14, but its exact value must be represented by a symbol, the Greek letter 7t. Pi is used in calculations involving lengths, areas, and vol¬

umes of circles, spheres, cylinders, and cones. It also arises frequently in problems dealing with certain periodic phenomena (e.g., motion of pen¬ dulums, alternating electric currents). By the end of the 20th century, com¬ puters had calculated pi to more than 200 billion decimal places.

Piaf, Edith \'pyaf\ English \'pe-,af\ orig. Edith Giovanna Gassion

(b. Dec. 19, 1915, Paris, France—-d. Oct. 11, 1963, Paris) French popular singer and actress. Her mother, a cafe singer, abandoned her at birth; Piaf became blind at age three as a result of meningitis but recovered her sight four years later. Her father, a circus acrobat, took her along on tours and encouraged her to sing. She sang for years in the streets of Paris until discovered by a cabaret owner who gave her her first nightclub job and suggested she change her name to Piaf, Parisian slang for “sparrow.” She was soon singing her chansons (ballads) in the large music halls of Paris. During World War II she entertained French prisoners of war and aided several in their escapes. She spent the postwar years touring, gaining worldwide fame with her intense performances of songs such as “Non, je ne regrette rien” (“No, I regret nothing”). Her throaty, expressive voice, combined with her fragile appearance and a dramatic tight spotlight on her face and hands, made her concerts memorable.

Piaget \pya-'zha\, Jean (b. Aug. 9, 1896, Neuchatel, Switz.—d. Sept. 17, 1980, Geneva) Swiss psychologist. Trained in zoology and philoso¬ phy, Piaget later studied psychology in Zurich (from 1918) with Carl Gustav Jung and Eugen Bleuler, and he was subsequently affiliated with the University of Geneva from 1929 until his death. He developed a theory of “genetic epistemology,” a natural timetable for the development of the child’s ability to think in which he traced four stages—the sensorimotor (ages 0-2), preoperational or symbolic (2-7), concrete operational (7-12), and formal operational (through adulthood)—each marked by increased cognitive sophistication and ability to use symbols. In 1955 Piaget founded and became director (to 1980) of an international centre for genetic epistemology in Geneva. His numerous books include The Lan¬ guage and Thought of the Child (1923), Judgment and Reasoning in the Child (1924), The Origin of Intelligence in Children (1948), and The Early Growth of Logic in the Child (1964). He is regarded as the foremost developmental psychologist of the 20th century.

piano or pianoforte Keyboard instrument with wire strings that sound when struck by hammers operated by a keyboard. It was invented in Florence by Bartolomeo Cristofori before 1720, with the particular aim of permitting note-to-note dynamic variation (lacking in the harpsichord). It differs from the older clavichord in that its hammers (rather than tan¬ gents) are thrown at the strings and bounce back, permitting the struck string to vibrate loudly. A cast-iron frame is needed to withstand the strings’ tremendous tension. Pianos have taken various shapes. The origi¬ nal harpsichord (or wing) shape has survived in the modern grand piano; the less-expensive square (actually rectangular) piano, standard in the early 19th century, was replaced by the upright piano, in which the strings are vertical. For at least 150 years the piano was the most important instrument in Western music. See illustration on following page.

piano nobile \,pya-n6-'n6-bi-la\ (Italian: “noble floor”) In a Renais¬ sance building, the first floor above ground level. In the typical palace erected by an Italian prince, the large, high-ceilinged reception rooms were in this upper, main story. Often a grand exterior staircase or pair of staircases led from ground level up to the piano nobile.

Piave River \'pya-va\ River, northeastern Italy. Rising in the Carnic Alps south of Lienz near the Austrian frontier, it flows south and south¬ east into the Adriatic Sea, east of Venice. It is 137 mi (220 km) long. Dur¬ ing World War I, its valley was the scene of several battles against the Austrians (see Battle of Caporetto). In 1966 the river burst its dikes in a major flood.

piazza \pe-'at-s9, pe-'a-z9\ Open square or marketplace, surrounded by buildings, in an Italian town or city. It was equivalent to the plaza of Spanish-speaking countries. The term became more widely used in the 16th-18th century, denoting any large open space with buildings around it. In 17th-18th-century Britain, long covered walks or galleries with roofs supported by columns were called piazzas; in the U.S. in the 19th cen¬ tury, piazza was another name for a veranda formed by projecting eaves.

Piazzetta \pyat-'tsat-ta\, Giovanni Battista or Giambattista Piazzetta (b. Feb. 13, 1682, Venice—d. April 28, 1754, Venice) Italian painter, illustrator, and designer. Trained as a wood carver by his father, he turned to painting and became one of the outstanding Venetian artists

1496 I Piazzolla ► Pkcolomini

hammer felt

hammer

hammer rest

hammer shank hammer butt

string

damper

catcher

back check

— tape

_- set-off button

escapement spring - support or wippen --capstan screw

jack (escapement)

Each key of a piano actuates a complex mechanical system to strike a taut string and produce a musical tone. Depending on how the keys and pedals are operated, the mechanism may produce a variety of effects on the same note, from muffled to brilliant and from quick to sustained.

of the 18th century. His art evolved from Italian Baroque traditions of the 17th century to the Rococo style. He had a strong influence on the young Giovanni Battista Tiepolo at the time he painted the finest of his early reli¬ gious works, St. James Led to Martyrdom (1722). His most popular work is the celebrated Fortune Teller (1740). On the founding of the Venetian Academy in 1750, he was made its first director.

Piazzolla \pyat-'so-ta\, Astor (b. March 11, 1921, Mar del Plata, Arg.—d. July 5, 1992, Buenos Aires) Argentine composer. He lived in the Bronx, N.Y., until he was 15; he then returned to Argentina to play ban- doneon (a type of accordion) in a tango band led by Anibal Troilo (1917— 75). From 1944 he led his own groups. His interest in classical music led to study with Nadia Boulanger (1954-55) and the development of his own compositional style, infusing elements of jazz and modern music into tango. Not always initially popular with tango fans, his music is now rec¬ ognized as having revived the genre and greatly expanded its artistic potential.

Picabia \pe-kab-'ya\, Francis (b. Jan. 22, 1879, Paris, France—d. Nov. 30, 1953, Paris) French painter, illustrator, designer, writer, and editor. After studying at the Ecole des Beaux-Arts and the Ecole des Arts Dec- oratifs, he painted for a time in an Impressionist and then a Cubist style. Picabia went on to combine the Cubist style with Orphic elements in such paintings as I See Again in Memory My Dear Udnie (1913-14), to which he gave proto-Dadaist names. About 1916 he began to paint the satiric, machinelike contrivances that are his chief contribution to Dadaism. In 1915 in New York City, Picabia, Marcel Duchamp, and Man Ray together founded an American Dadaist movement. In 1917 Picabia returned to Europe and joined Dadaist movements in Barcelona, Paris, and Zurich. After Dadaism broke up about 1921, he followed the poet Andre Breton into the Surrealist movement. He subsequently painted in Surrealist, abstract, and figurative styles.

Picardy Vpi-ksr-deX French Picardie \,pe-kar-'de\ Region (pop., 2003 est.: 1,869,386), encompassing the northern French departements of Oise, Somme, and Aisne and roughly coextensive with the historical region of Picardy. In the 13th century the historical region included the countships of Amienois and Vermandois, which were united with the French crown by Philip II from 1185. Picardy was joined to Burgundy in 1435 and attached to France in 1477. The province of Picardy from the 16th century to the end of the ancien regime in 1789 comprised the Somme River basin from Saint-Quentin to the English Channel, the basins of the Serre and upper Oise rivers, and Montreuil on the Canche beyond the Authie River. The region was the scene of heavy fighting in both world wars, especially in the First Battle of the Somme (1916). The capital of the French adminis¬ trative region of Picardy is Amiens. Picardy has an area of 7,490 sq mi (19,399 sq km).

picaresque novel Early form of the novel, usually a first-person nar¬ rative, relating the episodic adventures of a rogue or lowborn adventurer (Spanish, picaro ). The hero drifts from place to place and from one social milieu to another in an effort to survive. The genre originated in Spain and had its prototype in Mateo Aleman’s Guzman de Alfarache (1599). It appeared in various European literatures until the mid-18th century, when the growth of the realistic novel led to its decline. Because of the oppor¬ tunities for satire they present, picaresque elements enriched many later novels, such as Nikolay Gogol’s Dead Souls (1842), Mark Twain’s Huck¬ leberry Finn (1884), and Thomas Mann’s Confessions of Felix Krull

(1954).

Picasso, Pablo (Ruiz y) (b. Oct. 25, 1881, Malaga, Spain—d. April 8, 1973, Mougins, France) Spanish-born French painter, sculptor, print- maker, ceramicist, and stage designer. Trained by his father, a professor of drawing, he exhibited his first works at 13. After moving permanently to Paris in 1904, he replaced the predominantly blue tones of his so-called Blue Period (1901-04) with those of pottery and flesh in his Rose Period (1904-06). His first masterpiece, Les Demoiselles d Avignon (1907), was controversial for its violent treatment of the female body and the mask¬ like faces derived from his study of African art. From 1909 to 1912 Pi¬ casso worked closely with Georges Braque —the only time Picasso ever worked with another painter in this way—and they developed what came to be known as Cubism. The artists presented a new kind of reality that broke away from Renaissance tradition, especially from the use of per¬ spective and illusion. Neither Braque nor Picasso desired to move into the realm of total abstraction in their Cubist works, although they implicitly accepted inconsistencies such as different points of view, different axes, and different light sources in the same picture. By 1912 they had taken Cubism further by gluing paper and other materials onto their canvases. Between 1917 and 1924 Picasso designed stage sets for five ballets for Sergey Diaghilev’s Ballets Russes. In the 1920s and ’30s, the Surrealists spurred him to explore new subject matter, particularly the image of the Minotaur. The Spanish Civil War inspired perhaps his greatest work, the enormous Guernica (1937), whose violent imagery condemned the use¬ less destruction of life. After World War II he joined the Communist Party and devoted his time to sculpture, ceramics, and lithography as well as painting. In his late years he created variations on the works of earlier artists, the most famous being a series of 58 pictures based on Las Meni- nas of Diego Velazquez. For nearly 80 of his 91 years Picasso devoted himself to an artistic production that contributed significantly to and par¬ alleled the whole development of modern art in the 20th century.

Piccard \pe-'kar\, Auguste (b. Jan. 28, 1884, Basel, Switz.—d. March 24, 1962, Lausanne) Swiss-born Belgian physicist and balloon and under¬ sea explorer. He studied and taught physics in Zurich and later at the Uni¬ versity of Brussels (1922-54). In 1930 he designed a balloon with an airtight, pressurized cabin to ascend into the stratosphere to study cosmic rays. In 1932 he ascended over 55,500 ft (16,650 m). The undersea bathy¬ scaphe he designed with his son, Jacques (b. 1922), descended in 1953 more than 10,000 ft (3,000 m). His grandson Bernard Piccard made the first round-the-world balloon flight in 1999.

Piccolomini \,pek-k6-'l6-me-ne\ (-Pieri), Ottavio (b. Nov. 11, 1599, Florence—d. Aug. 11, 1656, Vienna) Italian general. He entered the ser¬ vice of the Habsburgs in 1616 and became a trusted lieutenant to Al¬ brecht Wenzel Eusebius von Wallenstein. Overlooked for advancement, he turned against his superior and conspired in his assassination (1634). He served Spain against the French in the Netherlands and won the Battle of Thionville (1639), for which he was created duke of Amalfi. In 1648 Emperor Ferdinand III named him commander in chief, and he conducted

picker ► Pieman River I 1497

the last campaign of the Thirty Years' War. He represented Austria at the Congress of Niirnberg (1649), which negotiated issues left unsettled by the Peace of Westphalia.

picker Machine for harvesting a crop (e.g., com, cotton) and preparing it for storage. The mechanical picker removes mainly the desired portion of the plant (e.g., grain and cobs of com, bolls of cotton) rather than har¬ vesting the entire plant.

pickerel Any of several North American pikes (family Esocidae), dis¬ tinguished from the northern pike and muskellunge by their smaller size, completely scaled cheeks and gill covers, and banded or chainlike mark¬ ings. The chain pickerel ( Esox niger) grows to about 2 ft (0.6 m) and a weight of about 3 lbs (1.4 kg). The barred ( E. americanus ) and grass (E. vermiculcitus ) pickerels reach a maximum weight of about 1 lb (0.5 kg).

Pickering, Timothy (b. July 17, 1745, Salem, Mass.—d. Jan. 29, 1829, Salem, Mass., U.S.) U.S. politician. He joined the militia in 1766 and served in the American Revolution under George Washington, becom¬ ing adjutant general (1777-78) and quartermaster general (1780-85). He later served as U.S. postmaster general (1791-95), secretary of war (1795), and secretary of state (1795-1800). He served in the U.S. Senate from 1803 to 1811 and in the House of Representatives from 1813 to 1817. A leader of the Federalist Party, he was a member of the Essex Junto, and he opposed the War of 1812. After retiring from politics, he turned to experimental farming and education.

picketing Act by workers of standing in front of or near a workplace to call attention to their grievances, discourage patronage, and, during strikes, to discourage strikebreakers. Picketing is also used in non-work- related protests. The U.S. Norris-LaGuardia Act (1932) made it easier for workers to picket by restricting the use of court injunctions against strikes, but the Taft-Hartley Act (1947) outlawed mass picketing.

Pickett, George E(dward) (b. Jan. 25, 1825, Richmond, Va., U.S.—d. July 30, 1875, Norfolk, Va.) U.S. and Confederate army officer. He graduated from West Point and served in the Mexican War. In 1861 he resigned his commission to enter the Confederate army. He rose to major general and commanded a division at the Battle of Fredericksburg. At the Battle of Gettysburg, he led the climactic attack known as Pickett’s Charge, in which 4,300 men of his division constituted almost half the attacking force under James Longstreet. The attempt to breach the Union lines on Cemetery Ridge was repulsed with the loss of about 60% of his men. Though criticized for his leadership, he retained his command.

Pickford, Mary orig. Gladys Mary Smith (b. April 9, 1893, Tor¬ onto, Ont., Can.—d. May 28, 1979, Santa Monica, Calif., U.S.) Canadian- born U.S. film actress. She acted with a stock company from age 5, went on tour at 8, and was performing on Broadway by 18. She starred in D.W. Griffith’s The Lonely Villa (1909) and by 1913 was acting in movies exclusively. One of the first movie stars, she became a symbol of inno¬ cence and was known as “America’s sweetheart.” Her silent films include Tess of the Storm Country (1914), Rebecca of Sunnybrook Farm (1917), Poor Little Rich Girl (1917), and Pollyanna (1920). A shrewd business¬ woman, she formed United Artists Corp. (1919) with her second husband, Douglas Fairbanks, and others. She received an Academy Award for her first sound film, Coquette (1929). She retired from acting in 1933 and received a special Academy Award in 1975.

Pico Bolivar See Bolivar Peak

Pico della Mirandola Vpe-ko-.dal-la-me-'ran-do-.laV Giovanni, conte (count) di Concordia (b. Feb. 24, 1463, Mirandola, duchy of Ferrara—d. Nov. 17, 1494, Florence) Italian scholar, philosopher, and humanist. He settled in Florence in 1484 as a protege of Lorenzo de' Med¬ ici and Marsilio Ficino. In 1486 he posted in Rome a list of 900 theses on logic, mathematics, physics, and other subjects that he proposed to defend against any opponent. His Oration on the Dignity of Man (1486), which accompanied the posting, epitomizes Renaissance humanism. Accused of heresy by the pope, he was later cleared, and he was later reconverted to orthodoxy by Girolamo Savonarola. Pico was the first Christian scholar to use Kabbalistic doctrine (see Kabbala) in support of Christian theology. His other works include Heptaplus (a seven-point exposition of the Book of Genesis) and a synoptic treatment of Plato and Aristotle, of which Of Being and Unity is a portion. He died at age 31.

picornavirus \pe-,k6r-n9-'vl-r9s\ Any of a group of the smallest known animal viruses. ( Pico refers to their small size, rna to their core of RNA.)

This group of spheroidal viruses includes viruses that attack the verte¬ brate intestinal tract and often invade the central nervous system as well (such as polioviruses), viruses that infect tissues in the vertebrate nose (rhinoviruses), and the virus agent of foot-and-mouth disease.

Piet Vpikt\ Any member of an ancient people of what is now eastern and northeastern Scotland. The name (from Latin picti, “painted”) referred to their body painting or tattooing. They were probably descended from pre- Celtic peoples. They attacked Hadrian's Wall in 297 and warred constantly with the Romans. They united their two kingdoms by the 7th century and converted to Christianity, and in 843 Kenneth I, king of the Scots, included them in the kingdom of Alba, later Scotland.

pictography \pik-‘ta-gr9-fe\ Expression of words and ideas through drawings (pictographs), considered a forerunner of true writing. Picto- graphs are drawn in a standardized way, omitting unnecessary details. A pictograph that stands for a specific idea or meaning is an ideogram; one that stands for an individual word is a logogram.

picturesque Artistic concept and style of the late 18th and early 19th century characterized by a preoccupation with architecture and landscape in pictorial combination with each other. In Britain, the picturesque was defined as an aesthetic quality marked by pleasing variety, irregularity, asymmetry, and interesting textures; medieval ruins in a natural landscape were thought to be picturesque. John Nash produced some of the most exemplary works embodying the concept. See also folly.

Picus Vpl-k9s\ In Roman mythology, a woodpecker sacred to Mars. A minor agricultural deity associated with the fertilization of the soil, Picus was widely worshiped in ancient Italy. Later versions of the myth made him an early king of Italy, whose bride, Circe, changed him into a wood¬ pecker. In art he was shown as a woodpecker mounted on a pillar, and later as a youth with a woodpecker on his head. The woodpecker was also an important bird in augury.

pidgin Vpi-jsnV Language with a very limited vocabulary and a simpli¬ fied grammar. Pidgins usually arise to permit communication between groups with no language in common; if a pidgin becomes established as the native language of a group, it is known as a creole. Pidgins such as Chinese Pidgin English and Melanesian Pidgin English arose through contact between English-speaking traders and inhabitants of East Asia and the Pacific islands. Other pidgins appeared with the slave trade in Africa and with the importation of West African slaves to Caribbean plantations. Most of the small vocabulary of a pidgin language (Melanesian Pidgin has only 2,000 words, Chinese Pidgin English only 700) is usually drawn from a single language (Melanesian Pidgin, for example, has an English word stock of more than 90%).

Piedmont \'ped-,mant\ Italian Piemonte \pya-'mon-ta\ Autonomous region (pop., 2001 prelim.: 4,166,442), northwestern Italy. With its capi¬ tal at Turin, Piedmont borders France and Switzerland; it has an area of 9,807 sq mi (25,399 sq km). In Roman times its passes connected Italy with the transalpine provinces of Gaul. In the Middle Ages the house of Savoy was the region’s most important power. It was a centre during the 19th-century Risorgimento that united Italy. Victor Emmanuel II, originally king of Piedmont and Sardinia, became modern Italy’s first king in 1861. Surrounded by mountains, Piedmont is centred on the Po River valley, which contains some of Italy’s best farmland, producing wheat, rice, and wines. Its hydroelectric plants supply energy for much of northern Italy.

Piedmont Geographic region, eastern U.S. Lying between the Appala¬ chian Mountains and the Atlantic coastal plain, it is about 600 mi (950 km) long and stretches between the Hudson River and central Alabama. A relatively low, rolling plateau crossed by many rivers, it is a fertile agri¬ cultural region.

Pielinen \'pe-9-,le-n9n\, Lake Lake, southeastern Finland. Located near the border with Russia, Lake Pielinen is 56 mi (90 km) long and has an area of 422 sq mi (1,093 sq km). The lake has many islands and is drained southward into Lake Saimaa by the Pielis River. It is surrounded by dense forests, especially on its western shore. The shore is capped by Koli hill, the centre of a winter sports area.

Pieman River VpI-msnV River, northwestern Tasmania, Australia. It is formed near Tullah by the confluence of the Macintosh and Murchison riv¬ ers. Rising on the western edge of the central highlands, it is about 70 mi (115 km) long and flows west to the Indian Ocean. There was some gold and tin mining in the area during the 1870s and 1890s. It was named for an

1498 I pier ► pig

infamous convict, Alexander Pierce (Jimmy the Pieman), who was recap¬ tured at its mouth after escaping from the Macquarie Harbour penal colony.

pier In building construction, a vertical load-bearing member such as an intermediate support for adjacent ends of two bays or spans. Bulkier than a column but smaller than a wall, a pier can support an arch or beam. The lower portion of a pier may be widened to better distribute the downward pressure of a massive overlying structure. In Romanesque and Gothic architecture, a feature of the nave arcade is the compound pier, which is cross-shaped in cross section, with shafts placed in the recesses.

Pierre \'pir\ City (pop., 2000: 13,876), capital of South Dakota, U.S. It is located on the Missouri River, in the geographic centre of the state. The

area was originally inhabited by Arikara Indians. The city was founded in 1880 as the western terminus of the Chicago and North Western Rail¬ way, which spurred its growth as a mining and trade centre. It became the state capital in 1889. It is the hub of a large, diversified agricultural area with a significant tourist industry based on nearby lakes.

Pieta \pya-'ta\ Italian "Pity" Depiction of the Virgin Mary supporting the body of the dead Christ. The theme grew out of that of the Lam¬ entation, the moment between the Descent from the Cross and the Entombment. It first appeared in Germany in the early 14th century. It enjoyed greater popularity in north¬ ern Europe than in Italy through the 15 th century, yet the supreme repre¬ sentation is Michelangelo’s sculpture (1499) in St. Peter's Basilica. The Pieta was widely represented in both painting and sculpture. Michelange¬ lo’s conception of Mary bearing Jesus’ body on her knees was stan¬ dard until the 16th century, when art¬ ists began to place Jesus at Mary’s feet. Though most religious art declined after the 17th century, the Pieta retained its popularity through the 19th century.

Pietism Vpi-a-.ti-zonA Reform movement in German Lutheranism that arose in the 17th century. Phil¬ ipp Jakob Spener (1635-1705), a Lutheran pastor, originated the move¬ ment when he organized an “assembly of piety,” a regular meeting of Christians for devotional reading and spiritual exchange. Spener advo¬ cated greater involvement of the laity in worship, more extensive study of scripture, and ministerial training that emphasized piety and learning rather than disputation. Under Spener’s successor, August Hermann Francke (1663-1727), the University of Halle became a centre of the movement. Pietism influenced the Moravian and Methodist churches (see Methodism).

Pietro da Cortona orig. Pietro Berrettini (b. Nov. 1, 1596, Cor¬ tona, Tuscany—d. May 16, 1669, Rome, Papal States) Italian painter, architect, and decorator. The son of a stonemason, he was apprenticed to a painter in Florence. His first major work, a series of frescoes in the small church of Santa Bibiana in Rome (1624-26), was commissioned by Pope Urban VIII, and the patronage of the pope’s family, the Barberinis, advanced Pietro’s career. The rich exuberance of those Baroque frescoes was a prelude to his best-known work, the large ceiling fresco Allegory of Divine Providence and Barberini Power (1632-39) in the Barberini Palace. Here he demonstrated his mastery of illusion, for the centre of the vault appears open to the sky and the figures seem to hover in space. He provided a series of frescoes for the Pitti Palace in Florence. Also a mas¬ ter architect, his greatest architectural accomplishment is the church of Santi Martina e Luca in Rome (1634), the first Baroque church built as a unitary whole.

piezoelectricity Xpe-.a-zo-o-.lek-'tri-so-teX Appearance of an electric field in certain nonconducting crystals as a result of the application of mechanical pressure. Pressure polarizes some crystals, such as quartz, by slightly separating the centers of positive and negative charge. The result¬ ant electric field is detectable as a voltage. The converse effect also occurs: an applied electric field produces mechanical deformation in the crystal. Using this effect, a high-frequency alternating electric current (see alter¬ nating current) can be converted to an ultrasonic wave of the same fre¬ quency, while a mechanical vibration, such as sound, can be converted into a corresponding electrical signal. Piezoelectricity is utilized in micro¬ phones, phonograph pickups, and telephone communications systems.

pig Any wild or domestic even-toed ungulate (family Suidae) that is a stout-bodied, short-legged omnivore, with thick, sparsely bristled skin, a long mobile snout, small tail, and hooves with two functional and two nonfunctional digits. Pigs are native to European, Asian, and North Afri¬ can forests. Wild pigs use their tusklike teeth to forage and for defense; the teeth of domestic pigs, which were developed from wild pigs in

Pieta, marble sculpture by Michelan¬ gelo, 1499; in St. Peter's Basilica, Rome.

SCALA/ART RESOURCE, NEW YORK

Pierce, Franklin (b. Nov. 23, 1804, Hillsboro, N.H., U.S.—d. Oct. : 1869, Concord, N.H.) 14th president of the U.S. (1853-57). He served in the U.S. House of Representatives from 1833 to 1837 and in the Senate from 1837 to 1842. At the dead¬ locked Democratic Party convention of 1852, he was nominated as a com¬ promise presidential candidate; though largely unknown nationally, he unexpectedly trounced Winfield Scott in the general election. For the sake of harmony and business pros¬ perity, he was inclined to oppose antislavery agitation. His promotion of U.S. territorial expansion resulted in the diplomatic controversy of the Ostend Manifesto. He reorganized the diplomatic and consular service and created the U.S. Court of Claims. Pierce encouraged plans for a transcontinental railroad and approved the Gadsden Purchase. To pro¬ mote northwestern migration and conciliate sectional demands, he approved the Kansas-Nebraska Act but was unable to settle the resultant problems. Defeated for renomination by James Buchanan in 1856, he retired from politics.

Franklin Pierce.

LIBRARY OF CONGRESS, WASHINGTON, D.C.

Piero della Francesca \fran-'ches-ko\ (b. c. 1420, Sansepolcro?, Republic of Florence—d. Oct. 12,

1492, Sansepolcro) Italian painter.

Son of a prosperous tanner and wool merchant, he became known for his serene, disciplined exploration of perspective. His fresco cycle for San Francesco at Arezzo, The Legend of the True Cross (1450s), exemplifies his simplicity and clarity of struc¬ ture, controlled use of perspective, and aura of serenity. His famous dip¬ tych portrait of his patrons, Count Federico da Montefeltro and his wife (c. 1470), is known for its unideal¬ ized depiction of their features and the use of landscape in the back¬ ground. Though he had little influ¬ ence on his contemporaries, Piero’s important scientific and poetic con¬ tributions to Renaissance painting are now well recognized. Also a writer, he produced theoretical treatises on geometry and perspective.

Piero di Cosimo \ko-'se-mo\ orig. Piero di Lorenzo (b. 1462,

Florence, Republic of Florence—d. 1521, Florence) Italian painter. His name derives from that of his master, Cosimo Rosselli, whom he assisted on frescoes for the Sistine Chapel. His later mythological paintings exhibit a bizarre Romantic style. Many are filled with fantastic hybrid human- animal forms engaging in revels ( The Discovery of Honey, c. 1500) or fights ( Battle of the Centaurs and the Lapiths, c. 1500). His art reflects his eccentric personality. He belonged to no school of painting but borrowed from many artists, including Sandro Botticelli and Leonardo da Vinci.

The Baptism of Christ, panel painting by Piero della Francesca, c. 1440-45; in the National Gallery, London.

pig iron ► Pilcomayo River I 1499

Europe c. 1500 bc, are less developed. Pigs are regarded as highly intel¬ ligent. Domestic pigs are classified as lard (thick fat, carcass weighing at least 220 lbs, or 100 kg), bacon (carcass about 150 lbs, or 70 kg), and pork (carcass about 100 lbs, or 45 kg) pigs, depending on the principal product derived from them; they are also a source of leather. Today they are usually bred in almost complete confinement. See also boar, hog.

pig iron Crude iron obtained directly from the blast furnace and cast in molds (see cast iron). The crude ingots, called pigs, are then remelted along with scrap and alloying elements and recast into molds to produce various iron and steel products (see Bessemer process, finery process, pud¬ dling process).

Pigalle \pe-'gal\, Jean-Baptiste (b. Jan. 26, 1714, Paris, France—d. Aug. 21, 1785, Paris) French sculptor. Born into a family of master car¬ penters, he began training as a sculptor in Paris at 18 and then studied in Rome (1736^40). Returning to France, he modeled the first version of his famous Mercury Fastening His Sandals, which in a later version won him admission to the Royal Academy (1744). The statue became so popular that in 1748 Louis XV commissioned a life-size marble version to present to Frederick II of Prussia. He was also noted for his portrait sculptures. His Nude Voltaire (1776), an anatomically realistic rendering of the aged phi¬ losopher, caused a furor when it was first shown.

pigeon Plump, small-billed, monogamous birds of the family Colum- bidae, found almost worldwide and recognizable by their head-bobbing strut. Unlike other birds, pigeons suck liquids and provide the young with regurgitated “pigeon’s milk.” The 175 species of true pigeons include the Old and New World Columba species and the Old World Streptopelia species; all eat seeds and fruit. Common street pigeons, or rock doves, are descendants of the Eurasian rock dove ( Columba livia). From antiquity pigeons were trained to carry messages over long distances. About 115 species of fruit pigeons occur in Africa, southern Asia, Australia, and the Pacific islands. The three species of crowned pigeons (genus Goura ), of New Guinea, are nearly the size of a turkey. See also dove; mourning dove; PASSENGER PIGEON; TURTLEDOVE.

pigeon hawk See merlin

pigment Any intensely coloured compound used to colour other mate¬ rials. Unlike dyes, pigments do not dissolve; they are applied as fine solid particles mixed with a liquid. In general, the same ones are used in oil- and water-based paints, printing inks, and plastics. They may be inorganic com¬ pounds (usually brighter and longer-lasting) or organic compounds. Natu¬ ral organic pigments have been used for centuries, but today most are synthetic or inorganic. The primary white pigment is titanium dioxide. Car¬ bon black is the most usual black pigment. Iron oxides give browns, rang¬ ing from yellowish through orange to dark brown. Chromium compounds yield chrome yellows, oranges, and greens; cadmium compounds brilliant yellows, oranges, and reds. The most common blues, Prussian blue and ultramarine, are also inorganic. Organic pigments, usually synthesized from aromatic hydrocarbons, include the nitrogen-containing azo pigments (red, orange, and yellow; see azo dyes) and the copper phthalocyanines (bril¬ liant, strong blues and greens). Chlorophyll, carotene, rhodopsin, and mela¬ nin are pigments produced by plants and animals for specialized purposes.

pika Vpe-ko, 'pi-ko\ Any of numerous round-eared, tailless members (genus Ochotona, family Ochoto- nidae) of the rabbit order (Lagomor- pha), found in Asia, eastern Europe, and parts of western North America.

Though not hares, they are some¬ times called mouse hares. The hind legs are less developed than a rab¬ bit’s; pikas scamper rather than bound. Their brownish or reddish fur is soft, long, and thick. Most pikas weigh between 4.5 and 7.1 oz. (125 and 200 g) and are about 6 in. (15 cm) long. Many species live in rocky, mountainous areas, but some Asian species inhabit burrows. Pikas do not hibernate, but in summer and autumn they “harvest” vegetation and store it in protected places (e.g., under rocks) to be eaten in winter.

pike Ancient and medieval infantry weapon consisting of a long, metal- pointed spear with a heavy wooden shaft 10-20 ft (3-6 m) in length. Its

use by Swiss foot soldiers in the 14th century contributed to the decline of the feudal knights. A variation is used by the picador in bullfighting.

pike Any of several voracious freshwater fishes (family Esocidae, order Salmoniformes) with a slender body, small scales, long head, shovel-like snout, large mouth, and strong teeth, and with dorsal and anal fins far back on the tail. The northern pike (Esox lucius) of North America, Europe, and northern Asia may grow to 4.5 ft (1.4 m) long and weigh 45 lbs (20 kg). A solitary hunter, it lies motionless or lurks among weeds, then suddenly lunges, seizing an approaching fish or invertebrate. Large species also take waterfowl and small mammals. See also muskellunge, pickerel.

RUSS KINNE-PHOTO RESEARCHERS

Pike, Kenneth L(ee) (b. June 9, 1912, Woodstock, Conn., U.S.—d. Dec. 31, 2000, Dallas, Tex.) U.S. linguist and anthropologist. Pike was associated throughout his career with the Summer Institute of Linguistics (now SIL International), an organization dedicated to linguistic study of little-known, unwritten languages, as an ancillary to Bible translation. He originated the linguistic theory known as tagmemics. The tagmeme, a unit comprising a function (e.g., a subject) and a class of items fulfilling that function (e.g., nouns), is identified by semantic as well as syntactic func¬ tion.

Pike, Zebulon Montgomery (b. Jan. 5, 1779, Lamberton, N.J., U.S.—d. April 27, 1813, York, Ont.) U.S. explorer. He joined the army at age 15. In 1805 he led an expedition to find the headwaters of the Mis¬ sissippi River, traveling 2,000 mi (3,200 km) from St. Louis to northern Minnesota, where he erroneously identified Leech Lake as the river’s source. In 1806 he was sent to the Southwest to explore the Arkansas and Red rivers. Passing through Colorado, he tried unsuccessfully to climb the 14,110-ft (4,301-m) mountain later named Pikes Peak. His party con¬ tinued into northern New Mexico (1807); his report on the Santa Fe region encouraged later expansion into the Southwest. In the War of 181 2 he was killed in the attack on York (Toronto).

Pikes Peak Mountain peak, eastern Colorado, U.S. It is located in the Front Range of the Rocky Mountains, near Colorado Springs. At 14,110 ft (4,301 m) in height, it is known for the panoramic view from its summit. It was discovered in 1806 by U.S. explorer Zebulon Pike. The view from it is said to have inspired Katharine Lee Bates to write “America the Beautiful” in 1893.

pilaster \pi-Tas-tar\ In Classical architecture, a shallow rectangular col¬ umn built into a wall and projecting slightly beyond it. It has a capital and base and conforms to one of the orders. In Roman architecture the pilas¬ ter gradually became more decorative than structural, and it served to break up otherwise empty expanses of wall.

Pilate \'pi-bt\, Pontius (d. ad 36) Roman prefect of Judaea (ad 26-36) who presided at the trial of Jesus and gave the order for his crucifixion. The New Testament represents Pilate as a weak and vacillating man who found no fault with Jesus but ordered his execution to please the mob calling for his death. Known for his severity toward the Jews, he was eventually ordered back to Rome to stand trial for cruelty and oppression. A tradi¬ tion of uncertain accuracy holds that he killed himself on orders from Caligula in ad 39; another legend relates that both Pilate and his wife con¬ verted to Christianity.

pilchard Vpil-ch9rd\ Local name in Britain and elsewhere for the Euro¬ pean sardine ( Sardina pilchardus ). It is found in the Mediterranean and off the Atlantic coasts of Spain, Portugal, France, and Britain.

Pilcomayo \,pel-ko-'ma-y6\ River River, south-central South America. The chief western tributary of the Paraguay River, it rises in the eastern Andes Mountains in west-central Bolivia. It flows southeast through the

American pika (Ochotona princeps).

KENNETH W. FINK/ROOT RESOURCES

1500 I pile ► Pima

Gran Chaco of Paraguay to join the Paraguay River opposite Asuncion, after about 1,000 mi (1,600 km). It forms part of the border between Argentina and Paraguay.

pile In building construction, a postlike foundation member used from prehistoric times. Piles transfer building loads down to a suitable bearing stratum when the soil mass immediately below a construction is unsuitable for the direct bearing of footings (see foundation). Piles support loads either by bearing directly on rock or suitable soil or by developing friction along their very ample length. In modern civil engineering, piles of timber, steel, or concrete are driven into the ground to support a structure; bridge piers and building foundations may be supported on groups of piles.

pile See hemorrhoid pileworm See shipworm

pilgrimage Journey to a shrine or other sacred place undertaken to gain divine aid, as an act of thanksgiving or penance, or to demonstrate devo¬ tion. Medieval Christian pilgrims stayed at hospices set up specifically for pilgrims, and on their return trip they wore on their hats the badge of the shrine visited. The chief attractions for pilgrims in the Middle Ages were the Holy Land, Santiago de Compostela in Spain, and Rome, but there were hundreds of local pilgrimage sites, including the tomb of St. Francis of Assisi and that of St. Thomas Becket in Canterbury. More recent pilgrimage sites include the shrine of Our Lady of Guadalupe in Mexico (1531), Lourdes in France (1858), and Fatima in Portugal (1917). The tradition of pilgrimage is also important in Buddhism, with sites including Bodh Gaya, where the Buddha received enlightenment, and Varanasi, where he deliv¬ ered his first sermon. In Islam all members of the faith are enjoined to per¬ form the HAJJ, the pilgrimage to Mecca, at least once in their lifetime.

Pilgrimage of Grace (1536) Uprising in the northern counties of England against the Reformation legislation of Henry VIII. Royal mandates to dissolve the monasteries in the north triggered riots in Lincolnshire and Yorkshire, where 30,000 armed rebels under Robert Aske occupied York, demanding a return to papal obedience and a parliament free from royal influence. Playing for time to assemble enough royal forces to oust the rebels, the 3rd duke of Norfolk made vague promises, and the rebels dis¬ persed, believing they had won, only to be arrested later; about 220 were executed, including Aske.

Pilgrims First settlers of Plymouth (Massachusetts), the first permanent colony in New England (1620). The members of the English Separatist Church, a radical faction of Puritanism, composed a third of the 102 colo¬ nists who sailed aboard the Mayflower to North America, and they became the dominant group in the colony. The settlers were later collectively referred to as the Forefathers; the term Pilgrim Fathers was applied to them by Daniel Webster at the bicentennial celebration (1820). See also Mayflower Compact; Plymouth Co.

pill bug Any species of terrestrial crustacean in the genera Armadilli- dium and Armadillo (both in the order Isopoda), native to Europe and introduced worldwide. Pill bugs (sometimes called wood lice) resemble tiny armadillos in appear¬ ance and behaviour; they have a gray, oval body covered with plate¬ like armour and, when disturbed, roll into a ball. They are about 0.75 in.

(19 mm) long. Pill bugs live in dry, sunny places, in dry leaf litter, and on forest edges. See also sow bug.

pillar Relatively slender isolated vertical structural member such as a pier or (usually squat) column. It may be constructed of a single piece of stone or wood or built up of units, such as bricks. A pillar commonly has a load-bearing or stabilizing function, but it may also stand alone, as do commemorative pillars.

Pillars of Hercules Two prom¬ ontories at the eastern end of the Strait of Gibraltar. They include the Rock of Gibraltar (at Gibraltar) in Europe and Jebel Musa (at Ceuta) in north¬

ern Africa. They are fabled to have been set there by Heracles as a memo¬ rial in his labour of seizing the cattle of the three-bodied giant Geryon.

Pillars of Islam See Pillars of Islam

Pillsbury Co. U.S. food-products company. It was established in Min¬ neapolis in 1871 as C.A. Pillsbury & Co. Its founder, Charles Alfred Pillsbury (1842-99), built the company into one of the world’s largest milling concerns in the 1880s, expanding the business by obtaining favourable freight rates and building his own grain elevators throughout the Northwest. He sold the firm to an English syndicate but remained its managing director until his death. Pillsbury later became a successful manufacturer of food products, acquiring subsidiaries such as Burger King, Haagen-Dazs, and Green Giant. It was acquired by Grand Metro¬ politan PLC (now Diageo PLC) in a hostile takeover in 1989, and in 2001 it was sold to former rival General Mills, Inc.

Pilon \pe-'lo n \, Germain (b. 1535, Paris, France—d. Feb. 3, 1590, Paris) French sculptor. His decoration of the tomb of Francis I (1558), a relatively early work, shows an Italian influence, but he later developed a distinctively French expression by fusing elements of Classical and Gothic art with the Fontainebleau adaptation of Mannerism. His best- known works are funerary sculptures for Henry II and Catherine de Medi- cis at St.-Denis (1561—70). His work represents a transitional link between the Gothic tradition and Baroque sculpture.

pilot fish Widely distributed species {Naucrates ductor, family Car- angidae) of carnivorous fish that inhabits warm and tropical open seas. It is slender and has a forked tail, a lengthwise keel on each side of the tail base, and a few small spines in front of the dorsal and anal fins. It may grow to 2 ft (60 cm) but is usually about 14 in. (35 cm) long. Five to seven distinctive vertical dark bands mark the bluish body. Pilot fishes follow sharks and ships, apparently to feed on parasites and leftover scraps. It was formerly thought that they were leading, or “piloting,” the larger fishes to food.

pilot whale Any of one to three species (genus Globicephala, family Delphinidae) of toothed whale found in all oceans except the Arctic and Antarctic, also called caa’ing whale for a roaring sound it makes when stranded. It is black, usually with a lighter splash on the throat and chest, and has a round, bulging forehead, a short beaklike snout, and slender, pointed flippers, and grows to 13-20 ft (4-6 m) long. Pilot whales live in large schools, sometimes hundreds or thousands, feeding mainly on squid. They have been kept in oceanariums and trained to perform.

Pitsudski \pil-'sut-ske, pil-'ziit-ske\, Jozef (Klemens) (b. Dec. 5, 1867, Zulow, Pol., Russian Empire—d. May 12, 1935, Warsaw, Pol.) Pol¬ ish revolutionary leader. Reared with a hatred for Russian oppression, he was politically active and was banished to Siberia for his socialist agita¬ tion (1887-92), and he became a leader of the Polish Socialist Party on his return. In 1908 he organized the secret Union of Military Action, which fought in World War I under Austro-Hungarian command against the Russians. In 1916 he demanded recognition of Poland’s independence, which was granted in 1918. He served as Poland’s first head of state until the constitution was established in 1922. After staging a coup in 1926, he served as premier (1926-28) and minister of defense (1926-35) under handpicked premiers, enabling him to rule as the dictator of Poland.

Piltdown hoax Forgery of human fossil remains that impeded early 20th-century progress in the study of human evolution. The apparently fossilized skull found at Piltdown Common near Lewes, Eng., was first proposed as a new species of prehistoric man (“Piltdown man”) in 1912. Only in 1954 was the skull shown to consist of a human cranium skill¬ fully joined to the jaw of an orangutan. The hoax may have been perpe¬ trated by the skull’s discoverer, Charles Dawson, though evidence discovered in the 1970s suggests a British Museum staff member, Martin A.C. Hinton.

Pima Vpe-m3\ North American Indian people living mainly in Arizona, U.S. The Pima language is of Uto-Aztecan language stock, and the name Pima was given by the Spanish, who may have derived it from the phrase pi-nyi-match, meaning “I don’t know.” They call themselves Akimel O’odham, meaning “River People.” Their traditional lands are located in the core area of the prehistoric Hohokam culture, from which they prob¬ ably descend. The Pima originally were sedentary com farmers who lived in one-room houses and used the Gila and Salt rivers for irrigation. Some hunting and gathering were also done. Their villages were larger than those of the related Papago Indians, and they possessed a stronger tribal

Pill bugs (Armadillidium vulgare)

E.S. ROSS

pimiento ► pineapple I 1501

unity. The Pima were long friendly with whites but enemies of the Apache. At the turn of the 21st century they numbered some 15,000.

pimiento or pimento Any of various mild peppers of the genus Cap¬ sicum that have distinctive flavour but lack pungency, including the Euro¬ pean paprikas. A common flavouring in Hungarian dishes, paprika is made by grinding dried peppers. The term pimento sometimes refers to allspice because early Spanish explorers of the West Indies and Central America mistook the highly aromatic berries of the tropical allspice tree for a type of pepper and called it pimenta.

pin (fastener) In mechanical and civil engineering, a peg or bar designed to fasten machine and structural components together or to keep them aligned. Dowel pins are used to keep machine components aligned, sometimes without making a rigid joint (as in a pin-connected truss). Taper pins are used to fix the hub of a gear or a pulley to a shaft. Split cotter pins prevent nuts from turning on bolts and keep loosely fitting pins in place. The clevis pin has a ridge at one end and is kept in place by a cotter pin inserted through a hole in the other end. Many other types of pins are used in various machines.

Pinatubo X.pe-na-'tii-boV, Mount Volcano, western Luzon, Philippines. Located about 55 mi (90 km) northwest of Manila, it rose to a height of about 4,800 ft (1,460 m) before its eruption in 1991 (for the first time in 600 years). Its explosions produced a column of smoke and ash more than 19 mi (30 km) high and left some 100,000 people homeless. The ashfalls forced the evacuation and eventual closing of a nearby U.S. Air Force base. The eruption was one of the largest of the 20th century.

Pinchback, Pinckney (Benton Stewart) (b. May 10, 1837, Macon, Ga., U.S.—d. Dec. 21, 1921, Washington, D.C.) U.S. politician. Born to a former slave and a white planter, he became a steward on river steamboats. At the outbreak of the American Civil War, he reached Union- held New Orleans, where he raised and led a company of black Union volunteers called the Corps d’Afrique (1862-63). After the war he was elected to the Louisiana senate (1868) and served as lieutenant governor (1871). Elected to the U.S. House of Representatives (1872) and Senate (1873), he was denied his seat in each body on unproved charges of elec¬ tion fraud. He subsequently became a lawyer and moved to Washington, D.C.

Pinchot Vpin-shoV, Gifford (b. Aug. 11, 1865, Simsbury, Conn., U.S.—d. Oct. 4, 1946, New York, N.Y.) U.S. forestry and conservation pioneer. He graduated from Yale University and studied forestry in Europe. In 1892 he became the first professional U.S. forester. In 1896 he joined the national forest commission of the National Academy of Sci¬ ences and helped plan the U.S. system of forest reserves (later national forests). As chief of the U.S. Forest Service (1898-1910), he established the nation’s forest-service system. He founded the Yale School of For¬ estry and taught there from 1903 to 1936. He served as governor of Penn¬ sylvania from 1923 to 1927 and from 1931 to 1935.

Pinckney, Charles (b. Oct. 26, 1757, Charleston, S.C.—d. Oct. 29, 1824, Charleston, S.C., U.S.) U.S. statesman. A cousin of Charles C. Pinckney and Thomas Pinckney, he fought in the American Revolution. From 1784 to 1787 he served in the Continental Congress, where he was instru¬ mental in calling for the Constitutional Convention. As a delegate to the convention from South Carolina, he proposed numerous provisions that were incorporated in the final draft of the Constitution of the United States. He helped write the South Carolina constitution and was also governor of the state (1789-92, 1796-98, 1806-08). He served in the U.S. Senate from 1798 to 1801 and as minister to Spain from 1801 to 1805.

Pinckney, Charles Cotesworth (b. Feb. 25, 1746, Charleston, S.C.—d. Aug. 16, 1825, Charleston, S.C., U.S.) U.S. soldier, statesman, and diplomat. A cousin of Charles Pinckney and the brother of Thomas Pinckney, he was an aide to George Washington in the American Revolu¬ tion, commanded at Savannah, Ga., and was promoted to brigadier gen¬ eral in 1783. He was a delegate to the Constitutional Convention. Appointed minister to France (1796), he was involved in negotiations that ended in the XYZ Affair; when one of the group of French negotiators suggested that the U.S. representatives offer a gift in order to gain a peace treaty, Pinckney is said to have replied, “No! No! Not a sixpence!” He was the unsuccessful Federalist candidate for vice president in 1800 and for president in 1804 and 1808.

Pinckney, Eliza orig. Elizabeth Lucas (b. c. Dec. 28, 1722, Anti¬ gua, West Indies—d. May 26, 1793, Philadelphia, Pa., U.S.) British-

American planter. The daughter of a British landowner in South Carolina, she managed his plantations from 1739. Experimenting with various crops, she succeeded in marketing the first American crop of indigo. After her marriage to the lawyer Charles Pinckney (1744), she revived the cul¬ tivation of silkworms and manufacture of silk on his plantation. She con¬ tinued to manage their extensive landholdings after his death (1758). Charles C. Pinckney and Thomas Pinckney were her sons.

Pinckney, Thomas (b. Oct. 23, 1750, Charleston, S.C.—d. Nov. 2, 1828, Charleston, S.C., U.S.) U.S. soldier, politician, and diplomat. The brother of Charles C. Pinckney and a cousin of Charles Pinckney, he served as governor of South Carolina (1787-89) and as minister to Britain (1792- 96). As special envoy to Spain (1795), he negotiated the Treaty of San Lorenzo, also called Pinckney’s Treaty, which fixed the southern border of the U.S. and granted the U.S. navigation rights on the Mississippi River and the right of deposit (storage of goods) at New Orleans. He was a major general in the War of 1812.

Pindar (b. 518/522, Cynoscephalae—d. c. 438 bc, Argos) Greek poet. A Boeotian of aristocratic birth, Pindar was educated in neighbouring Athens and lived much of his life in Thebes. Almost all his early poems have been lost, but his reputation was probably established by his later hymns in honour of the gods. He developed into the greatest lyric poet of ancient Greece, respected throughout the Greek world. Of his 17 vol¬ umes, comprising almost every genre of choral lyric, only four have sur¬ vived complete, and those lack his musical settings. The extant poems, probably representing his masterpieces, are odes (see Pindaric ode) com¬ missioned to celebrate triumphs in various Hellenic athletic games. Lofty and religious in tone, they are noted for their complexity, rich metaphors, and intensely emotive language.

Pindaric ode Ceremonious poem in the manner of Pindar, who employed a triadic, or three-part, structure consisting of a strophe (two or more lines repeated as a unit) followed by a metrically harmonious antistrophe and an epode (summary line) in a different metre. The three parts correspond to movements onstage by the chorus in Greek drama. After the 16th-century publication of Pindar’s choral odes in the epinicion (celebratory) form, poets writing in various vernaculars created irregular rhymed odes that suggest his style. Such odes in English are among the greatest poems in the language, including John Dryden’s “Alexander’s Feast,” William Wordsworth’s “Ode: Intimations of Immortality,” and John Keats’s “Ode on a Grecian Urn.”

pine Any of 10 genera of coniferous trees (rarely shrubs) of the family Pinaceae (see conifer), native to northern temperate regions, espe¬ cially about 90 species of ornamen¬ tal and timber evergreen conifers of the genus Pinus. Needlelike leaves and cones are solitary or in bunches.

Shallow root systems make pines susceptible to wind and surface dis¬ turbance. The family includes fir,

Douglas fir, hemlock, spruce, larch, and cedar. Many species are sources of softwood timber, paper pulp, oils, and resins. Some are cultivated as ornamentals.

pineal Vpl-ne-ol, pI-'ne-oL gland or pineal body Endocrine gland in the brain that produces melatonin.

It is large in children and begins to shrink at puberty. The gland may play a significant role in sexual maturation, circadian rhythm and sleep induc¬ tion, and SEASONAL AFFECTIVE DISORDER and depression. In animals it is known to play a major role in sexual devel¬ opment, hibernation, and seasonal breeding.

pineapple Fruit-bearing plant (Ananas comosus) of the family Bro- meliaceae, native to the New World tropics and subtropics but introduced elsewhere. Pineapple is served fresh where available and in canned form worldwide. It is a key ingredient in

Cluster of pollen-bearing male cones of Austrian (black) pine (Pinus nigra).

GRANT HEILMAN/EB INC.

1502 I Pinero ► pinworm

Polynesian cuisine. Like agave and some yuccas, the plant has a rosette of 30-40 stiff, succulent leaves on a thick, fleshy stem. A determinate inflorescence forms 15-20 months after planting. After fertilization, the many lavender flowers fuse and become fleshy to form the 2^1 lb (1-2 kg) fruit. Ripening takes 5-6 months.

Pinero \pi-'nir-6\, Sir Arthur Wing (b. May 24, 1855, London, Eng.—d. Nov. 23, 1934, London) British playwright. He entered the the¬ atrical world as an actor with Henry Irving’s theatre company. His first play, £200 a Year, was produced in 1877. He wrote a series of successful farces such as The Magistrate (1885) before turning to dramas of social issues. The Second Mrs. Tanqueray (1893), the first of his plays depict¬ ing women confronting their situation in society, established his reputa¬ tion, and he followed it with works such as The Notorious Mrs. Ebbsmith (1895) and Trelawny of the “ Wells ” (1898), becoming the most success¬ ful playwright of his time.

Ping Pong See table tennis

Pinilla, Gustavo Rojas See Gustavo Rojas Pinilla

pinion See gear, rack and pinion

Pinios River \,pe-ne-'6s\ or Peneus River \pi-'ne-os\ River, Thessaly, north-central Greece. It rises in the Pindus Mountains and flows about 125 mi (200 km) southeast and northeast through the plain of Thessaly and the Vale of Tempe into the Gulf of Salonika (see Thessaloniki). In pre¬ historic times it formed a great lake before it broke through the Vale of Tempe. It is navigable in its lower course.

pink family Family Caryophyllaceae, composed of 2,070 species of flowering plants in 89 genera found mainly in northern temperate regions. The approximately 300 species of true pinks belong to the genus Dianthus\ relatively easy to grow, these are popular in rock gardens for their fragrant, showy flowers. Though members of the pink family are diverse in appear¬ ance and habitat, most have swollen leaf and stem joints. The family includes carnations, baby's breath, sweet William, campion, and chickweed.

pink salmon Food fish (Oncorhynchus gorbuscha, family Salmonidae) of the North Pacific that constitutes half of the commercial fishery of Pacific salmon. It weighs about 4.5 lbs (2 kg) and is marked with large, irregular spots. Pink salmon often spawn on tidal flats. The young enter the sea immediately after hatching.

Pinkerton National Detective Agency U.S. independent police force. The agency was founded in 1850 by Allan Pinkerton (1819-84), former deputy sheriff of Cook county, Ill. It originally specialized in rail¬ way theft cases, protecting trains and apprehending train robbers. It solved the $700,000 Adams Express Co. theft in 1856, and in 1861 it thwarted an assassination plot against president-elect Abraham Lincoln. It later par¬ ticipated in anti-labour union activities (see Homestead Strike). It was instrumental in breaking up the Molly Maguires.

Pinkham Vpiqk-omX, Lydia E(stes) (b. Feb. 9, 1819, Lynn, Mass., U.S.—d. May 17, 1883, Lynn) U.S. patent-medicine proprietor. Pinkham began making Vegetable Compound as a home remedy, sharing it with her neighbours. Her compound, a blend of ground herbs, was 18% alco¬ hol by content. In 1875 the Pinkham family decided to go into business selling the medicine, which Pinkham claimed could cure any “female complaint” from nervous prostration to a prolapsed uterus. It quickly gained acceptance, and the business was soon grossing close to $300,000 a year. Not until the 1920s, when federal regulation of drugs and adver¬ tising increased, did the Lydia E. Pinkham Medicine Co. reduce both the alcohol content of the medicine and the claims for its efficacy.

pinniped Vpi-no-.pedX Any member of the three existing families of aquatic, fin-footed mammals that constitute the suborder Pinnipedia (order Carnivora; see carnivore). They include the Odobenidae (see walrus) and the Phocidae and Otariidae (see seal).

Pinochet (Ugarte) \,pe-n9-'sha,\ Spanish V.pe-no-'cheV Augusto (b. Nov. 25, 1915, Valparaiso, Chile) Head of Chile’s military government (1974-90). A career military officer, he planned and led the coup d’etat in which Pres. Salvador Allende died. He immediately moved to crush liberal opposition and in the next three years arrested about 130,000 Chileans and foreigners, many of whom were tortured and some of whom were killed. He led a rapid transition to a free-market economy, which slowed inflation but led to acute hardship for the lower classes. A new constitution in 1981 granted him eight more years as president. Rejected in a plebiscite in 1989,

he stepped down after free elections installed Patricio Aylwin in 1990. In 1998 he was arrested in England at the request of Spain and held for trial for crimes against Spanish citizens in Chile during his tenure; he was released 16 months later. He was then indicted in Chile for the murder of dissidents but was declared mentally unfit for trial.

pinochle Vpe-.no-kolX Card game. In one popular version of pinochle three players use two packs of 24 cards ranking ace, 10, king, queen, jack, and 9 of each suit. Each player is dealt 15 cards, 3 at a time. Bidding is based on certain combinations of cards within the player’s hand and an estimation of tricks, or hands, the player can win. The name derives from Binokel, a German game resembling bezique.

Pinsky, Robert (b. Oct. 20, 1940, Long Branch, N.J., U.S.) American poet and critic. Pinsky was poetry editor of The New Republic from 1979 to 1986. His own poems, many of which are to be found in The Figured Wheel: New and Collected Poems (1996), often explore the meaning of ordinary acts. He also did a notable verse translation of Dante’s Inferno (1994). Pinsky was poet laureate consultant from 1997 to 2000.

pintail Any of four species (genus Anas, family Anatidae) of sleek, long-tailed, long-necked dabbling ducks that are swift fliers and popular game birds. The common, or northern, pintail (A. acuta), widespread in the Northern Hemisphere, is a long-distance flier; some Alaskan birds winter in Hawaii. It is 26-30 in. (66-75 cm) long. The male has a white breast, gray back, and black tail; the female is mottled brown. The pre¬ ferred diet is seeds. The brown, or yellow-billed, and the Bahama, or white-cheeked, pintails are primarily found in South America. The red¬ billed pintail is a grayish African species.

Pinter, Harold (b. Oct. 10, 1930, London, Eng.) British playwright. Born into a working-class family, he acted with touring companies until 1959. His early one-act plays were followed by the full-length The Birth¬ day Party (1958). His next major plays. The Caretaker (1960) and The Homecoming (1965), established his reputation as an innovative and com¬ plex dramatist, sometimes considered as belonging to the Theatre of the Absurd. He often used disjointed small talk and lengthy pauses in dialogue to convey a character’s thought, which often contradicts his speech. Pint¬ er’s laterplays include Old Times (1971), No Man's Land (1975), Betrayal (1978; film, 1983), Mountain Language (1988), and Moonlight (1993). He also wrote radio and television plays as well as screenplays for The Go-Between (1970), The French Lieutenant’s Woman (1981), and The Handmaid’s Tale (1990). In 2005 he won the Nobel Prize for Literature.

pinto Spotted horse, also called paint, piebald, skewbald, and other terms to describe variations in colour and markings. The American Indian ponies of the western U.S. were often pintos. Most pure-breed associations refuse to register horses with pinto colouring. Pintos have colour patterns called overo (white spreading irregularly up from the belly, mixed with a darker colour) and tobiano (white spreading down from the back in smooth, clean-cut patterns).

Pinturicchio V.pen-tii-'rek-kyoN or Pintoricchio \,pen-t6-'rek-kyo\ orig. Bernardino di Betto di Biago (b. c. 1454, Perugia, Romagna—d. Dec. 11, 1513, Siena, Republic of Siena) Italian painter. He assisted Perugino on the frescoes in the Vatican’s Sistine Chapel (1481-82). Painting in the early Renaissance style, he was more interested in deco¬ rative effects than in clarity of design; his most important work, the fresco decoration of six rooms in the Bor¬ gia Apartments for Pope Alexander VI (1492-94), features brilliant colours, gilding, and ancient Roman ornamental motifs. His last major works were 10 scenes from the life of Pius II in the Piccolomini Library of Siena Cathedral. He was also a prolific panel painter.

pinworm Common species (Enterobius vermicularis) of NEMA¬ TODE parasitic to humans, especially children. Female pinworms may be 0.5 in. (13 mm) long; males are much smaller. Pinworms have a very long tail that gives them a pinlike appearance. They mate in the upper gastrointestinal tract, usually in the

Pio ► piranha I 1503

large intestine; the females travel to the anus, deposit their fertilized eggs on the skin near the anal opening, and die. The worms’ movements cause itching; eggs transferred to the fingernails when the victim scratches may be passed to the mouth. Eggs can also be inhaled with air dust. The eggs or larvae make their way to the intestine, and the cycle begins again.

Pio, Padre orig. Francesco Forgione (b. May 25,1887, Pietreclina, Italy—d. Sept. 23, 1968, San Giovanni Rotondo) Italian priest. Born into a devout Catholic family, he consecrated himself to Jesus at 5. At 15 he joined the Capuchins and took the name Pio; in 1910 he became a priest. That same year he received the stigmata for the first time. They were healed, but he received them again in 1918; this time they remained with him until his death. This and other signs of his holiness (perfume and, reportedly, the ability to be in two places at once), drew growing num¬ bers of pilgrims to him. He was canonized in 2002.

Piombo, Sebastiano del See Sebastiano del Piombo

Pioneer First series of unmanned U.S. deep-space probes. Pioneers 0-4 were all intended to be lunar missions, but only Pioneer 4 succeeded in escaping Earth’s gravity (1964). Pioneer 1 was the first spacecraft launched by NASA (1958). Pioneers 6-9 were successfully launched into solar orbits (1965-68) to study the solar wind, solar magnetic field, and cosmic rays. Pioneer 10, launched in 1972, was the first space probe to traverse the asteroid belt and the first to fly by Jupiter (1973), where it discovered Jupi¬ ter’ s huge magnetic tail. It then became the first man-made object to exit the solar system. Pioneer ll’s data and photographs (1979) enabled scientists to identify two previously undiscovered moons and an additional ring around Saturn and radiation belts in its magnetosphere. Two Pioneer Venus spacecraft, the Orbiter and the Multiprobe (Pioneer 12 and 13, respec¬ tively), reached Venus in 1978. The Orbiter observed the planet’s clouds and atmosphere and mapped its surface by radar; the Multiprobe released four instrument packages into the atmosphere at different locations.

pipa Vpe-'pa\ or p'i-p'a Short-necked Chinese lute. It has a pear- shaped body and a fretted fingerboard, and the silk strings are plucked with the fingernails. It is prominent in the opera orchestra and as an ensemble, solo, and accompanying instrument. The Japanese biwa is a similar instrument.

pipe, sacred See calumet

Pipestone National Monument National monument, southwest¬ ern Minnesota, U.S. Established in 1937, it has an area of 282 acres (114 hectares) and contains quarries of a reddish-coloured stone that was used by the Plains Indians to make ceremonial peace pipes. The stone is reserved for use by the Indians, who quarry it under special permits from the National Park Service. Henry Wadsworth Longfellow popularized the quarries in “The Song of Hiawatha.”

pipit or fieldlark Any of about 50 species (especially in the genus Anthus ) of small, slender-bodied, ground-dwelling songbirds belonging to the family Motacillidae. Found worldwide except in polar regions and on some islands, they are brownish-streaked and 5-9 in. (12-23 cm) long. They have a thin, pointed bill, pointed wings, and elongated hind toes and claws. Named for their twittering sounds, they walk and run rapidly (but never hop), searching the ground for insects. Their flight is strongly undu¬ lating. Their white outer tail feathers show best in flight. See also wagtail.

Pippin \'pe-pon\ III or Pepin or Pippin the Short (b. c. 714—d.

Sept. 24, 768, Saint-Denix, Neustria) King of the Franks (751-768), the first king of the Carolingian dynasty and the father of Charlemagne. A son of Charles Martel, he became mayor of Neustria, Burgundy, and Provence in 741 and de facto ruler of the Franks when his brother entered a mon¬ astery in 747. With the backing of the pope, he deposed the last Merov¬ ingian ruler, Childeric III, in 751 and was crowned king by the bishops of his realm and, possibly, by the papal legate St. Boniface. Pippin was crowned king in 754 by Pope Stephen II. The king bestowed on the pope the Donation of Pippin and invaded Italy twice (754, 756) to protect the pope from the Lombards. He also put down revolts in Saxony and Bavaria and struggled to subdue rebellious Aquitaine. Pippin called several church councils and promoted religious reform in the kingdom.

Pippin, Horace (b. Feb. 22, 1888, West Chester, Pa., U.S.—d. July 6, 1946, West Chester) U.S. folk painter. Pippin served in the infantry in World War I, but he was wounded in 1918 and discharged with a partially paralyzed right arm. His first large canvas was an eloquent protest against war, End of the War: Starting Home (1931-34). His primary theme

became the African American experience, as seen in his series entitled Cabin in the Cotton (mid 1930s) and his paintings of episodes in the lives of the antislavery leader John Brown and Pres. Abraham Lincoln. After the art world discovered Pippin in 1937, he received wide acclaim as the greatest black painter of his time.

piracy Illegal act of violence, detention, or plunder committed for pri¬ vate ends by the crew of a private ship (usually) against another ship on the high seas. Air piracy (i.e., the hijacking of an aircraft) is a more recent phenomenon. Piracy has occurred in all stages of history: the Phoenicians, Greeks, and Romans engaged in it, as did the Vikings, Moors, and other Europeans. It also occurred among Asian peoples. During the wars between England and Spain in the late 16th century, treasure-laden Span¬ ish galleons proceeding from Mexico into the Caribbean were a natural target for pirates. In the 16th—18th centuries pirates from North Africa’s Barbary Coast threatened commerce in the Mediterranean. The increased size of merchant vessels, improved naval patrolling, and recognition by governments of piracy as an international offense led to its decline in the late 19th century. In the late 20th century incidents of piracy occurred with increasing frequency in the seas of East and Southeast Asia. See also Blackbeard; Francis Drake; Jean Laffite; Henry Morgan.

Piraeus \pl-'re-9s\ City (pop., 2001: 175,697), port of Athens, Greece. The port and its “long walls,” fortified barriers connecting it with Athens, were completed in the mid-5th century bc. The walls were destroyed by Sparta at the end of the Peloponnesian War. Rebuilt under the Athenian leader Conon in 393 bc, Piraeus was burned in 86 bc by the Roman com¬ mander Lucius Cornelius Sulla. The city regained importance after ad 1834, when Athens became capital of the newly independent Greece. The largest port in Greece, it is the centre for all sea communication with the Greek islands.

Pirandello, Luigi (b. June 28, 1867, Agrigento, Sicily, Italy—d. Dec. 10, 1936, Rome) Italian playwright and novelist. He earned a doctorate in philology at the University of Bonn but turned to writing poetry, short stories, and several novels, including the successful The Late Mattia Pascal (1904). His first major play, Right You Are (if You Think You Are) (1917), explored the relativity of truth, a lifelong subject for Piran¬ dello. Six Characters in Search of an Author ( 1921) contrasted art and life; it was followed by the tragedy Henry IV (1922). His other plays include Each in His Own Way (1924) and Tonight We Improvise (1930). He established the Teatro d’Arte in Rome and toured the world with his company (1925-27). Recognized as a major figure in 20th-century theatre, he was awarded the Nobel Prize for Literature in 1934.

Piranesi X.pe-ra-'na-seX, Giovanni Battista or Giambattista Piranesi (b. Oct. 4, 1720, Mestre, near Venice—d. Nov. 9, 1778, Rome, Papal States) Italian draftsman, printmaker, architect, and art theorist. He went to Rome at 20 as a draftsman for the Venetian ambassador. After settling there in 1747, he developed a highly original etching technique that produced rich textures and bold contrasts of light and shadow. His many prints of Classical and post-Classical Roman structures contributed to the growth of Classical archaeology and the Neoclassical ait movement. He is best known today for his extraordinary series of imaginary prisons (Carceri d’invenzione, 1745). His prints are among the most impressive architectural representations in Western art.

piranha Vpo-'ra-no, po-'ran-yoN or caribe \k3-'re-be\ Any of several species of deep-bodied, carnivorous fishes in the genus Serrasalmus (fam¬ ily Characidae), abundant in rivers of eastern and central South America and noted for voracity. The red-bellied piranha ( S . nattereri ) grows to 2 ft (60 cm) long, but most species are smaller. Some species are silvery with an orange belly and throat; others are almost completely black. All have sharp, saw-edged teeth that close in a scissorlike bite. Traveling in groups, they usually prey on other fishes, but red-bellied piranhas occasionally con¬ verge on larger animals. Though generally scavengers, they are attracted to the scent of blood and can quickly reduce even a large animal to a skeleton.

Luigi Pirandello.

COURTESY OF THE ITALIAN INSTITUTE, LONDON

1504 I Pirquet ► piston and cylinder

Pirquet \pir-'ka\, Clemens, baron von (b. May 12, 1874, Vienna, Austria—d. Feb. 28, 1929, Vienna) Austrian physician. In 1906 he noticed that patients who received two injections of horse serum or smallpox vac¬ cine usually had quicker, more severe reactions (which he called “aller¬ gies”) to the second injection. While studying cowpox vaccination symptoms, he also developed a new theory about infectious diseases’ incubation times and about antibody formation. In the Pirquet test, a drop of tuberculin is scratched into the skin; a red, raised area developing at the site (Pirquet reaction) indicates tuberculosis.

Pisa \'pe-zo,\ Italian Vpe-sa\ ancient Pisae City (pop., 2001 prelim.: 85,379), central Italy. Located on the Arno River, Pisa probably began as an Etruscan town. It became a Roman colony c. 180 bc. A Christian bish¬ opric by ad 313, it flourished during the Middle Ages as the principal urban centre of Tuscany. Pisa’s participation in the Crusades made it a rival of Genoa and Venice. It became part of the Kingdom of Italy in 1860. The city was the scene of heavy fighting during World War II. It is now an important railway junction. Its cathedral, the Leaning Tower of Pisa, and other attractions, make it a tourist destination. It is the site of the Univer¬ sity of Pisa (founded 1343) and the birthplace of Galileo.

Pisano \pi-'sa-no, pi-'za-n6\, Andrea or Andrea da Pontedera

(b. c. 1270-90, Pontedera, near Pisa—d. c. 1348/49, Orvieto, Papal States) Italian sculptor and architect. He created the earliest of three bronze doors for the Baptistery of the cathedral of Florence (1330-36). On Giotto’s death in 1337, Andrea succeeded him as chief architect of the cathedral’s bell tower, to which he added two stories adorned with panel reliefs. In 1347 he was appointed superintending architect of the cathedral of Orvi¬ eto. One of the most important Italian sculptors of the 14th century, he is known for his restrained style and skillful arrangement of figures.

Pisano, Giovanni (b. c. 1250, Pisa—d. after 1314, Siena?) Italian sculptor and architect. His early work is similar to that of Nicola Pisano, his father and teacher. About 1285 he began work on the facade of Sie¬ na’s cathedral, whose lavish and ordered design and ornamentation became the model for future Gothic facade decoration in central Italy. His other great achievement, the Pistoia pulpit (c. 1298-1301), is character¬ ized by extreme agitation, its figures, animals, drapery, and landscape being wrenched into physically impossible configurations. His pulpit for the Pisa cathedral (1302-10) is much more Classical, perhaps to accord with Giotto’s monumental style, then in the ascendancy. Though regarded as Italy’s only true Gothic sculptor, he never lost sight of the heritage of Classical Rome.

Pisano, Nicola (b. c. 1220, Apulia?—d. 1278/84, Pisa?) Italian sculp¬ tor. His work, along with that of his son, Giovanni Pisano, created a new sculptural style for the late 13th and 14th centuries in Italy. His greatest work, the pulpit in the Baptistery of Pisa Cathedral (1260), is extraordi¬ nary in its assertion of a new style, distinct from all its predecessors though indebted to them. The work draws on many motifs, including Roman reliefs, early Christian fres¬ coes and mosaics, and French Gothic architecture and sculpture, but assimilates them, creating a unified whole that gave a new sense of direc¬ tion to Tuscan art.

Pisces \'pl-,sez\ (Latin: “Fishes”) In astronomy, the constellation lying between Aries and Aquarius; in astrology, the twelfth sign of the zodiac, governing approximately the period February 19-March 20. Its symbol is two fish tied together. These are a reference to the Greek myth of Aph¬ rodite and Eros, who jumped into a river to escape the monster Typhon and were changed into fish. In another version of the myth, two fish carried them to safety.

Pishpek See Bishkek

Pisidia \pi-'si-de-o\ Ancient region, southern Anatolia. Most of it was composed of the Taurus Mountains, which provided refuge for a lawless population that resisted successive conquerors. It was incorporated into the Roman province of Galatia in the early 1st century ad and became

part of Lycia and Pamphylia under the emperor Vespasian in ad 74. Dio¬ cletian included Pisidia in the diocese of Asia c. 297. During Byzantine times it continued to be a region of revolt. By 1204 the Byzantine Empire had lost control of the region to Turkish invaders.

pistachio \p3-'sta-she-,o\ Any of nine species of aromatic trees and shrubs, some ornamental, that make up the genus Pistacia of the sumac (or cashew) family, native to Eurasia, with one species in southwestern North America and another in the Canary Islands. Commercial pistachio nuts are seeds from the fruit of P. vera. They have a pleasing, mild, res¬ inous flavour and are used extensively as food and for yellowish green colouring in confections. The tree bears leaves with thick, wide, leathery, featherlike leaflets and small fruit in clusters.

pistil Female reproductive part of a flower. Centrally located, the pistil typically has a swollen base called the ovary, which contains the poten¬ tial seeds (ovules). The stalk (style) arises from the ovary and has a pollen- receptive tip, the stigma, which is variously shaped and often sticky. There may be a single pistil, as in the lily, or several to many pistils, as in the buttercup. Each pistil is constructed of one to many rolled leaflike struc¬ tures, or carpels. Differences in the composition and form of the pistil are useful in classifying flowering plants. See also stamen.

pistol Small firearm designed to be operated with one hand. The name may derive from the city of Pistoia, Italy, where handguns were made as early as the 15th century. It was originally a cavalry weapon. However, because the firepower of pistols must be kept low in order to reduce them to manageable weight, and because only skilled soldiers can shoot them accurately beyond 10 yards, they have never been satisfactory military weapons. In legal use, pistols are most frequently carried by police and other security personnel and serve mainly as a defensive weapon of last resort. Their compact size, low cost, and ease of operation make them a common weapon in violent crime, so that pistols are a common object of laws regulating the ownership of firearms. The two classes of pistol are revolvers and automatics. Automatics have a mechanism, actuated by the energy of recoil, that feeds cartridges from a magazine in the grip. See illustration on opposite page.

piston and cylinder In mechanical engineering, a sliding cylinder with a closed head (the piston) that moves up and down (or back and forth) in a slightly larger cylindrical chamber (the cylinder) by or against pressure of a fluid, as in an engine or pump. The cylinder of a steam engine is closed by plates at both ends, with provision for the piston rod, which is rigidly attached to the piston, to pass through one of the end cover plates. The cylinder of an internal-combustion engine is closed at one end by a plate called the head and open at the other end to permit free oscil¬ lation of the connecting rod, which joins the piston to the crankshaft.

Adoration of the Magi (detail) by Nicola Pisano, c. 1259-60; part of the marble pulpit in the Baptistery at Pisa.

AUNARI/ART RESOURCE, NEW YORK

Pissarro \po-'sar-o\, (Jacob-Abraham-) Camille (b. July 10, 1830, St. Thomas, Danish West Indies—d. Nov. 13, 1903, Paris,

France) West Indian-born French painter. The son of a prosperous Jew¬ ish merchant, he moved to Paris in 1855. His earliest canvases are broadly painted figure paintings and landscapes; these show the careful observation of nature that was to remain a characteristic of his art. In 1871 he took a house in Pontoise, in the countryside outside Paris. These surroundings formed the theme of his art for some 30 years. Pissarro’s leading motifs during the 1870s and 1880s were houses, factories, trees, haystacks, fields, labouring peasants, and river scenes. In these works, forms do not dissolve but remain firm, and colours are strong; during the latter part of the 1870s his comma-like brushstrokes frequently recorded the sparkling scintillation

of light. These works were admired by the Impressionist artists; Pissarro was the only Impressionist painter who participated in all eight of the group’s exhibitions. Despite acute eye trouble, his later years were his most prolific.

Self-portrait by Camille Pissarro, oil on canvas, 1903; in the Tate Gallery, Lon¬ don.

pit bull terrier ► Pitt I 1505

pit bull terrier or Staffordshire terrier Dog breed developed in 19th-century Britain for fighting other dogs in pits. It was created by crossing the bulldog (which at the time was longer-legged and more agile) with a terrier, possibly the fox terrier. Once known by such names as bull- and-terrier and half-and-half, the pit bull is a stocky, muscular, unusually strong dog with powerful jaws, standing 17-19 in. (43^48 cm) tall and weighing 30-50 lb (14-23 kg). Its stiff, short coat may be any colour, solid or variegated. See also bull terrier.

pit viper Any species of viper (subfamily Crotalinae) that has, in addi¬ tion to two movable fangs, a heat-sensitive pit organ between each eye and nostril which together help it accurately aim its strike at its warm¬ blooded prey. Pit vipers are found from deserts to rain forests, primarily in the New World. They may be terrestrial, arboreal, or aquatic. Some species lay eggs; others produce live young. See also bushmaster, copper¬ head, FER-DE-LANCE, MOCCASIN, RATTLESNAKE.

Pitcairn Island Island (pop., 2003 est.: 47) and British overseas ter¬ ritory, south-central Pacific Ocean. It is the only inhabited island of the Pitcairn island group, which also includes Henderson, Ducie, and Oeno islands. It has an area of about 2 sq mi (5 sq km). Discovered in 1767 by the British, it was uninhabited until 1790, when it was settled by muti¬ neers from HMS Bounty, led by Fletcher Christian. Pitcairn was annexed by Britain in 1838. The inhabitants were removed to Norfolk Island in 1856 because of overpopulation. Some returned to Pitcairn, and it is their descendants who make up the present population, subsisting on fishing and farming. In 1970 the British High Commissioner in New Zealand was appointed Pitcairn’s governor.

pitch In music, position of a single sound in the complete range of sound; this quality varies with the number of vibrations per second (hertz, Hz) of the sounding body and is perceived as highness or lowness. A higher pitch has a higher number of vibrations. In Western music, standard pitches have long been used to facilitate tuning. A confusing variety of pitches prevailed until the 19th century, when the continual rise in pitch made some international agreement a matter of practical necessity. In 1939 the A above middle C was standardized as 440 Hz. See also inter¬ val; TUNING AND TEMPERAMENT.

pitchblende Amorphous, dense, black, pitchy form of the crystalline uranium oxide mineral uraninite; it is one of the primary mineral ores of uranium. Pitchblende is found in granular masses and has a greasy lustre. Three chemical elements were first discovered in pitchblende: uranium, polonium, and radium. Deposits, frequently in association with uraninite or with secondary uranium minerals, are known in the Czech Republic, Britain, the Northwest Territories and Saskatchewan in Canada, and Ari¬ zona, Colorado, Montana, New Mexico, and Utah in the U.S.

Pitcher, Molly (b. c. 1753—d. Jan. 22, 1832, Carlisle, Pa., U.S.) U.S. patriot. Little is known of her early life, though she is thought to have been Irish. In the American Revolution she accompanied her husband, William Hays, a gunner, at the Battle of Monmouth (1778), where she carried pitchers of water to wounded American soldiers, earning the nickname “Molly Pitcher.” According to legend, after her husband collapsed from

the heat, she took his place at the cannon and served heroically through the battle. In 1822 she was recognized for her heroism with a state pension. Some historians attribute the act of replacing her husband at the cannon to Margaret Corbin (1751-1800) in the attack on Fort Washington in 1776.

pitcher plant Any carnivorous plant with pitcher-, trumpet-, or urn¬ shaped leaves. Several families include pitcher plants: Nepenthaceae (Old World pitcher plants), Cephal- otaceae, Asclepiadaceae (milkweed family), and especially Sarraceni- aceae (New World pitcher plants, particularly those in the eastern North American genus Sarracenia).

Pitcher plants inhabit bogs, swamps, wet or sandy meadows, or savannas where the soils are water-saturated, acidic, and deficient in nitrates or phosphates. Their unusual tubular leaves have a series of nectar- secreting glands that extend from the lip down into the interior and attract insects. Once in the plant, the prey tumbles down into a liquid pool and drowns, after which an enzyme secreted within the leaf digests it, releasing nitrates and other nutrients, which supplement the meager nutrient supply of bogs. Most pitcher plants produce pitcher-shaped, insect-catching leaves in the spring and tubeless leaves in the fall. Their flowers are showy and have an agreeable scent.

pitot tube \'pe-,to\ Instrument for measuring the velocity (speed) of a flowing fluid. Invented by Henri Pitot (1695-1771), it consists of a tube with a short, right-angled bend, which is placed vertically in a moving fluid with the mouth of the bent part directed upstream; the pressure, mea¬ sured with an attached device, depends on the fluid flow and can be used to calculate the velocity. Pitot tubes are used to measure airspeed in wind tunnels and aboard aircraft in flight; they are also used to measure the flow of liquids (see flow meter).

Pitt, William, the Elder later 1st earl of Chatham (b. Nov. 15, 1708, London, Eng.—d. May 11,1778, Hayes, Kent) British statesman and orator, twice virtual prime minister (1756-61, 1766-68). He entered Par¬ liament in 1735 and provoked controversy with his maiden speech, which criticized the ministry of Robert Walpole. With the outbreak of the Seven Years' War, he was named secretary of state and became virtual prime min¬ ister. His leadership brought many British victories that greatly extended the British Empire. His wide popular appeal led to the nickname “the Great Commoner,” though he was disliked by many in government for his high¬ handedness. He resigned in 1761 when the cabinet refused to declare war on Spain. He became a champion of liberty and spoke in favour of Ameri¬ can colonial resistance to the Stamp Act. He formed another government in 1766, in which he served as lord privy seal, but he resigned in 1768 because of ill health. Widely mourned on his death in 1778, he was buried in West¬ minster Abbey.

Pitt, William, the Younger (b.

May 28, 1759, Hayes, Kent,

Eng.—d. Jan. 23, 1806, London)

British statesman and prime minister (1783-1801, 1804-06). The son of William Pitt, he entered Parliament in 1781 and served as chancellor of the Exchequer (1782-83). He was appointed prime minister in 1783 and undertook reforms that reduced the large national debt incurred by the American Revolution, reduced tar¬ iffs, placed the East India Co. under government control, and restructured the government in India. Forced into conflict with France by the French Revolutionary Wars, he formed a series of coalitions with European states against France (1793, 1798,

1805). Pitt responded to demands by radicals for parliamentary reform

Yellow pitcher plant (Sarracenia flava).

JEFF LEPORE/PHOTO RESEACHERS

William Pitt the Younger, detail of an oil painting by John Hoppner; in the National Portrait Gallery, London.

COURTESY OF THE NATIONAL PORTRAIT GALLERY, LONDON

1506 I pittosporum ► Pizarro

with repressive measures. In 1800 he secured the Act of Union with Ire¬ land but resigned in 1801 when his proposal for Catholic emancipation was denied. His second term as premier (1804-06) was marked by the collapse of the Third Coalition after the Battles of Ulm and Austerlitz, the news of which weakened his already fragile health.

pittosporum \p3-'tas-p3-r3m\ Any of various evergreen shrubs or trees, mainly from Australia and New Zealand, that make up the genus Pittosporum (family Pittosporaceae), commonly known as Australian lau¬ rel. They are planted especially as ornamentals in warm regions. The most popular and hardiest species, called tobira, or house-blooming mock orange ( P. tobira), is native to China and Japan; it is a popular fragrant hedge plant in warm climates and a handsome indoor plant elsewhere.

Pittsburgh City (pop., 2000: 334,563), southwestern Pennsylvania, U.S. It is situated at the confluence of the Allegheny and Monongahela rivers where they form the Ohio River. In 1758 the French Fort Duquesne was captured there by the British, and the site was renamed Pitt. It was incorporated as a borough in 1794 and as a city in 1816. In the 19th cen¬ tury it developed rapidly as a steel-manufacturing centre. The American Federation of Labor began there in 1881 (see AFL-CIO). The second- largest city in the state, it is the centre of an urban industrial complex that includes several neighbouring cities. There are more than 150 industrial research laboratories in the area. It is home to the University of Pittsburgh, Carnegie Mellon University, and other educational institutions.

Pittsburgh Platform Manifesto of Reform Judaism, drawn up in 1885 by a conference of rabbis chaired by Isaac Mayer Wise in Pittsburgh, Pa. It declared that Judaism taught the highest conception of God, but it rec¬ ognized the efforts of other religions to grasp the truth. The Bible was understood as the primary instrument of moral and religious instruction even though it reflected the primitive ideas of the time of its composition. It rejected the Mosaic and rabbinic laws regulating diet and dress, accept¬ ing only those laws that elevate the spirit. The Pittsburgh Platform looked forward to the messianic kingdom and accepted the immortality of the soul but not resurrection of the body. It advocated social justice and uni¬ versal moral reform and maintained that Judaism was an evolving reli¬ gion. It remained the official philosophy of the U.S. Reform movement until 1937, when the Columbus Platform moved Reform Judaism back to a more traditional position.

pituitary \p9-'tu-3-,ter-e\ gland or hypophysis \hI-'paf-3-s9s\ Endocrine gland lying on the underside of the brain. It plays a major part in regulating the endocrine system. Its anterior lobe secretes most of the pituitary hormones, which stimulate growth (see growth hormone); egg and sperm development; milk secretion; release of other hormones by the thyroid gland, adrenal glands, and reproductive system; and pigment pro¬ duction. The posterior lobe stores and releases hormones from the hypo¬ thalamus that control pituitary function, uterine contraction and milk release, and blood pressure and fluid balance.

Pius \'pi-9s\ II orig. Enea Silvio Piccolomini (b. Oct. 18, 1405, Cor- signano, Republic of Siena—d. Aug. 14/15. 1464, Ancona, Papal States) Pope (1458-64). An Italian diplomat who became bishop of Trieste (1447) and Siena (1449), he mediated between the German princes and the papacy, arranged the coronation of Frederick III as Holy Roman emperor (1452), and made peace with Aragon and Naples. As pope he tried to unite Europe in a Crusade against the Turks, but he was unable to win the sup¬ port of the Christian princes. Pius was also a noted humanist and a pro¬ lific writer on the events of his day.

Pius V, Saint orig. Antonio or Michele Ghislieri (b. Jan. 17, 1504, Bosco, duchy of Milan—d. May 1, 1572, Rome, Papal States; can¬ onized May 22, 1712; feast day April 30) Pope (1566-72). He joined the Dominican order at age 14 and was ordained in 1528. A relentless pur¬ suer of heretics, he was named commissary general of the Inquisition in 1551. By 1556 he was a cardinal, and in 1566 he was elected pope. He zealously carried out church reforms and succeeded in keeping Protes¬ tantism out of Italy. In 1570 he excommunicated Elizabeth I, thus worsen¬ ing the position of Catholics in England. He organized the campaign that led to the victory of the Spanish, Venetian, and papal fleets over the Turks in the Battle of Lepanto in 1571.

Pius IX orig. Giovanni Maria Mastai-Ferretti (b. May 13, 1792, Senigallia, Papal States—d. Feb. 7, 1878, Rome; beatified Sept. 3, 2000; feast day February 7) Pope (1846-78). He became an archbishop in 1827, a cardinal in 1840, and pope on the death of Gregory XVI (1831-46). He

set out to make liberal reforms, but the revolutionary fervour of 1848 frightened him into extreme conser¬ vatism. He proclaimed the dogma of the Immaculate Conception (1854) and convened the First Vatican Council (1869-70), which promulgated the doctrine of papal infallibility. After los¬ ing temporal power to Victor Emman¬ uel II upon Italian unification, he regarded himself as a “prisoner in the Vatican” and refused any contact with the Italian government. Pius’s pontificate was the longest in history.

He was beatified in 2000 by Pope John Paul II (1978-2005).

Pius X, Saint orig. Giuseppe Melchiorre Sarto (b. June 2,

1835, Riese, Venetia, Austrian Empire—d. Aug. 20, 1914, Rome,

Italy; canonized May 29, 1954; feast day August 21) Pope (1903-14). Born in the Italian region of Venetia, he became bishop of Mantua in 1884 and patriarch of Venice in 1893. He was elected pope in 1903 and soon became known both for his piety and for his staunch religious and politi¬ cal conservatism. Pius suppressed the Catholic intellectual movement known as Modernism and opposed the political movement for social reform known as Christian Democracy. He worked to organize the laity for collaboration in the church’s apostolic work, and he reformed the Catho¬ lic liturgy. His decision to systematize canon law led to the publication of the new code in 1917, which became effective in 1918.

Pius XII orig. Eugenio Maria Giuseppe Giovanni Pacelli (b.

March 2, 1876, Rome, Italy—d. Oct.

9, 1958, Castel Gandolfo) Pope (1939-58). Before succeeding Pius XI in 1939, he served in the papal diplomatic service and as secretary of state to the Holy See. He was active in humanitarian work with prisoners and refugees during World War II but has been criticized by some for not having done more to prevent or battle the Holocaust. In the postwar era he was a defender of persecuted Catholics in communist countries. Known for his austere conservatism, he in 1950 defined the dogma of the bodily Assumption of the Virgin.

Pius, Sextus Pompeius Mag¬ nus See Sextus Pompeius Magnus Pius

pixel in full picture element Smallest resolved unit of a video image that has specific luminescence and colour. Its proportions are determined by the number of lines making up the scanning raster (the pattern of dots that form the image) and the resolution along each line. In the most com¬ mon form of computer graphics, the thousands of tiny pixels that make up an individual image are projected onto a display screen as illuminated dots that from a distance appear as a continuous image. An electron beam creates the grid of pixels by tracing each horizontal line from left to right, one pixel at a time, from the top line to the bottom line. A pixel may also be the smallest element of a light-sensitive device, such as cameras that use charge-coupled devices (see CCD).

Pizarro, Francisco (b. c. 1475, Trujillo, Extremadura, Castile—d. June 26, 1541, Lima) Conquistador who seized the Inca empire for Spain. In 1510 he enrolled in an expedition of exploration in the New World, and three years later he joined Vasco Nunez de Balboa on the expedition that discovered the Pacific. He made two voyages of discovery down the Colombian coast (1524-25, 1526-28) and continued his explorations southward, naming the new territory Peru. In 1531 he set sail for Peru with his 4 brothers, 180 men, and 37 horses. He soon encountered emissaries of the Inca emperor, Atahuallpa, and arranged a meeting. There his men slaughtered the emperor’s unarmed retainers and took him hostage. After

Pius IX.

FELICI

Pius XII, photograph by Yousuf Karsh.

Pizarro ► planarian I 1507

accepting a rich ransom for Atahuallpa’s release, Pizarro had him garroted. He spent the rest of his life consolidating Spain’s hold on Peru. He founded Lima (1535), where he was killed by fellow Spaniards he had betrayed.

Pizarro, Gonzalo (b. 1502?, Trujillo, Spain—d. April 10, 1548, Cuzco, Peru) Spanish explorer and conqueror. With his half brother Fran¬ cisco Pizarro, he took part in the conquest of Peru (1531-33), for which he received extensive land grants and was made governor of Quito (1539). In 1541—42 he led a disastrous expedition into the unexplored region east of Quito that cost the lives of almost 200 Spaniards and 4,000 Indians. He returned to find that Spain had restricted the conquerors’ privileges; the conquistadores revolted against the viceroy, and Pizarro led the anti¬ royalist forces to victory at the Battle of Anaquito (1546), but they were defeated in 1548, and he was executed.

pizza Food of Neapolitan origin. It consists of a flattened disk of bread dough, typically topped with olive oil, tomatoes, and mozzarella cheese, baked quickly, and served hot. Pizza is eaten throughout Italy, with regional variations in toppings. Pizza came to the U.S. with Italian immi¬ grants; the first U.S. pizzeria opened in 1905, and pizza became one of the nation’s favourite foods after World War II. It is now popular world¬ wide.

PKK See Kurdistan Workers Party PKU See PHENYLKETONURIA

PL Kyodan \'pe- , el- , ky6-dan\ in full Perfect Liberty Kyodan Reli¬ gious group founded in Japan by Miki Tokuchika in 1946 as a revival of his father’s group, Hito-no-michi. Unaffiliated with any of the major reli¬ gious traditions of Japan, it teaches that the goal of human life is joyful self-expression. Misfortune and suffering come from forgetting God, but the believer may pray that his troubles be transferred to the patriarch, who is strengthened for vicarious suffering by the group’s collective prayers. Today PL Kyodan claims more than 2.5 million adherents worldwide. The sect’s headquarters are at Habikino, near Osaka.

placenta \pb-'sen-t3\ Organ in most mammals that develops in the uterus along with a fetus to mediate metabolic exchange. The umbilical cord attaches it to the fetus at the navel. Nutrients and oxygen in the mother’s blood pass across the placenta to the fetus, and metabolic wastes and car¬ bon dioxide from the fetus cross in the other direction; the two blood sup¬ plies do not mix. Other substances (e.g., alcohol or drugs) in the mother’s blood can also cross the placenta, with effects including congenital disor¬ ders and drug addiction in the newborn (see fetal alcohol syndrome); some microorganisms can cross it to infect the fetus, but so do the mother’s antibodies. The placenta, weighing a pound or more at the end of preg¬ nancy, is expelled at parturition. Some animals eat it as a source of nutri¬ ents; in some species this stimulates lactation.

placer deposit Natural concentration of heavy minerals caused by the effect of gravity on moving particles. When heavy, stable minerals are freed from their matrix by weathering processes, they are slowly washed downslope into streams that quickly winnow the lighter matrix. Thus the heavy minerals become concentrated in stream, beach, and lag (residual) gravels and constitute workable ore deposits. Minerals that form placer deposits include gold, platinum, cassiterite, magnetite, chromite, ilmenite, rutile, native copper, zircon, monazite, and various gemstones.