construction: Early concrete structures: …is a portion of the Baths of Diocletian (c. 298–306) with a span of 26 metres (85 feet); it was converted into the church of Santa Maria degli Angeli by Michelangelo in the 16th century. The other is the Basilica of Constantine (307–312 ce), also with a span of 26…

Palace of Diocletian, ancient Roman palace built between 295 and 305 ce at Split (Spalato), Croatia, by the emperor Diocletian as his place of retirement (he renounced the imperial crown in 305 and then lived at Split until his death in 316). The palace constitutes the main part of a UNESCO World

clay mineral: General features: …called trioctahedral, and the latter dioctahedral. If all the anion groups are hydroxyl ions in the compositions of octahedral sheets, the resulting sheets may be expressed by M2+(OH)2 and M3+(OH)3, respectively. Such sheets, called hydroxide sheets, occur singly, alternating with silicate layers in some clay minerals. Brucite, Mg(OH)2, and gibbsite,…

John Milton: Early life and education: Paul’s Milton befriended Charles Diodati, a fellow student who would become his confidant through young adulthood. During his early years, Milton may have heard sermons by the poet John Donne, dean of St. Paul’s Cathedral, which was within view of his school. Educated in Latin and Greek there,…

Giovanni Diodati was a Swiss Calvinist pastor known for his translation of the Bible into Italian. Born of a refugee Protestant family from Lucca, Diodati became a pastor at Geneva in 1608 and professor of theology in 1609. A leader of the Reformers, he was an eloquent, bold, and fearless preacher

diode, an electrical component that allows the flow of current in only one direction. In circuit diagrams, a diode is represented by a triangle with a line across one vertex. The most common type of diode uses a p-n junction. In this type of diode, one material (n) in which electrons are charge

electricity: Electroluminescence: …in a reverse-biased semiconductor p–n junction diode—i.e., a p–n junction diode in which the applied potential is in the direction of small current flow. Electrons in the intense field at the depleted junction easily acquire enough energy to excite atoms. Little of this energy finally emerges as light, though the…

tactics: Combined infantry and cavalry: …Alexander and his successors (diodochoi) operated on a much greater scale than did most of their predecessors. The most important diodochoi were quite capable of concentrating 80,000 to 100,000 men at a single spot, as did both Ptolemy IV and his Seleucid opponent Antiochus III at Raphia in 217…

porcupine fish: …the world, especially the species Diodon hystrix. They are related to the puffers and, like them, can inflate their bodies when provoked.

porcupine fish, any of the spiny, shallow-water fishes of the family Diodontidae, found in seas around the world, especially the species Diodon hystrix. They are related to the puffers and, like them, can inflate their bodies when provoked. Porcupine fishes are short and broad-bodied, with large

patristic literature: The school of Antioch: …century, in the person of Diodore of Tarsus (c. 330–c. 390), that the school of Antioch began to reach the height of its fame. Diodore courageously defended Christ’s divinity against Julian the Apostate, the Roman emperor who attempted to revive paganism, and in his lifetime was regarded as a pillar…

Diodorus Cronus was a philosopher of the Megarian school, remembered for his innovations in logic. His surname Cronus, of uncertain meaning, was applied both to him and to his teacher, the philosopher Apollonius of Cyrene. Through Apollonius he is linked with Eubulides of Miletus, a 4th-century

Diodorus Siculus was a Greek historian, the author of a universal history, Bibliothēkē (“Library”; known in Latin as Bibliotheca historica), that ranged from the age of mythology to 60 bc. Diodorus lived in the time of Julius Caesar and Augustus, and his own statements make it clear that he

Diodotus I was the satrap (governor) of the Seleucid province of Bactria, who, with his son of the same name, founded the Greek kingdom of Bactria. At first subject to the Seleucid king Antiochus I and later to Antiochus II, Diodotus rebelled in about 250 and took the title of king. Little is known

Diodotus II was the king of Bactria, the son and successor of Diodotus I. Although his father’s freedom from Seleucid control is uncertain, Diodotus II unquestionably ruled as an independent king and issued coinage in his own name. He further proclaimed the independence of the kingdom of Bactria by

plant reproductive system: Angiosperms: poplars, and mulberries, which are dioecious. In common parlance (and unfortunately in some botanical textbooks), staminate flowers and plants that bear them are often designated “male,” and pistillate flowers and the plants that bear them are called “female.” This may be traced back at least as far as to the…

Fanny Lewald: Diogena (1847) is a parody of Gräfin Faustine, a sentimental novel by Lewald’s rival, Ida, Countess von Hahn-Hahn. In the historical novel Prinz Louis Ferdinand, 3 vol. (1849), Rahel Varnhagen von Ense, an early 19th-century Berlin literary hostess, is the central figure.

Diogenes was the archetype of the Cynics, a Greek philosophical sect that stressed stoic self-sufficiency and the rejection of luxury. He is credited by some with originating the Cynic way of life, but he himself acknowledges an indebtedness to Antisthenes, by whose numerous writings he was

Diogenes Laërtius was a Greek author noted for his history of Greek philosophy, the most important existing secondary source of knowledge in the field. One of its traditional titles, Peri biōn dogmatōn kai apophthegmatōn tōn en philosophia eudokimēsantōn (“Lives, Teachings, and Sayings of Famous

Diogenes Of Apollonia was a Greek philosopher remembered for his cosmology and for his efforts to synthesize ancient views and new discoveries. It is uncertain whether Diogenes’ birthplace, from which his name is derived, was the Apollonia of Crete or that of Phrygia (in modern Turkey). He lived

Diogenes of Babylon was a Greek Stoic philosopher remembered chiefly for his visit to Rome in 156–155 bce, which served to arouse interest in the Stoic creed among the Romans. Diogenes was born at Seleucia on the Tigris, a centre of Hellenistic culture in Mesopotamia. He studied in Athens under

Epicureanism: The Epicurean school: …the 2nd century ce belongs Diogenes of Oenoanda, who carved Epicurus’s works on a portico wall. In the same century should perhaps be mentioned Diogenianus, fragments of whose polemic against the Stoic Chrysippus are found in the church historian Eusebius of Caesarea. Also Epicurean, between the 4th and 5th centuries,…

Monument of Lysicrates, only extant example of the ancient Greek architectural structure known as the choragic monument. For architects in the 18th century, the Monument of Lysicrates, located in Athens, was a common inspiration for decorative

Epicureanism: The Epicurean school: …century should perhaps be mentioned Diogenianus, fragments of whose polemic against the Stoic Chrysippus are found in the church historian Eusebius of Caesarea. Also Epicurean, between the 4th and 5th centuries, was the epigrammatist Palladas.

achondrite: …groups: acapulcoites, angrites, aubrites, chassignites, diogenites, eucrites, howardites, lodranites, nakhlites, shergottites, and ureilites. The howardites, eucrites, and diogenites (HEDs) are from the large asteroid Vesta. The shergottites, nakhlites, and chassignites almost certainly came from Mars. In addition, a

Letter to Diognetus, early Christian apologetic work probably dating from the 2nd or 3rd century ce. An insightful piece of patristic literature, it is often included with the works of the Apostolic Fathers (Greek Christian writers of the late 1st and early 2nd centuries) or associated with the

American Idol: …of a fourth judge, songwriter Kara DioGuardi. Judges were also given the power to directly influence the final rounds of competition with the “judges’ save rule,” which allowed the panel to override the votes of the viewing public once per season to give a deserving contestant a second chance. In…

The Gambia: Ethnic groups: The Diola (Jola) are the people longest resident in the country; they are now located mostly in western Gambia. The largest group is the Malinke, comprising about one-third of the population. The Wolof, who are the dominant group in Senegal, also predominate in Banjul. The Fulani…

hydrocarbon: Nomenclature of alkenes and alkynes: …double bonds are classified as dienes, those with three as trienes, and so forth. Dienes are named by replacing the -ane suffix of the corresponding alkane by -adiene and identifying the positions of the double bonds by numerical locants. Dienes are classified as cumulated, conjugated, or isolated according to whether…

ancient Greek civilization: The decline of the aristocracy: …famous engineering feat, the so-called diolkos (“portage way”). The diolkos, which was excavated in the 1950s, was a line of grooved paving-stones across which goods could be dragged for transshipment (probably not the merchant ships themselves, though there is some evidence that warships, which were lighter, were so moved in…

Diomede Islands, two small islands in the Bering Strait, lying about 2.5 miles (4 km) apart and separated by the U.S.–Russian boundary, which coincides with the International Date Line. The larger island, Big Diomede (Russian: Ostrov Ratmanova [Ratmanov Island]), has an area of 4 square miles (10

procellariiform: Distribution: …two Midway species and the short-tailed albatross (Diomedea albatrus) nest well north of the equatorial doldrums. The latter was brought close to extinction by plume hunters and by a volcanic eruption at its nesting island of Torishima. There were enough immature birds at sea at the time to allow a…

albatross: The Amsterdam albatross (D. amsterdamensis) has a wingspread of 280–340 cm (9–11 feet). Once thought to be a subspecies of the wandering albatross, it was shown by DNA analysis in 2011 to have diverged from the wandering albatross more than 265,000 years ago. The species exists…

albatross: The royal albatross (D. epomophora), with a wingspread to about 315 cm (about 10 feet), is largely white with black outer wing surfaces. It breeds on islands near New Zealand and near the southern tip of South America.

albatross: The wandering albatross (D. exulans) has the largest wingspread among living birds—to more than 340 cm (11 feet). The adult is essentially like the royal albatross. It nests on islands near the Antarctic Circle and on some islands in the South Atlantic, and in the nonbreeding…

albatross: The laysan albatross (Phoebastria immutabilis), with a wingspread to about 200 cm, has a white body and dark upper wing surfaces. Its distribution is about the same as the black-footed albatross.

procellariiform: Distribution: One species, the waved albatross (D. irrorata), is unique in that it breeds only in the Galapagos Islands at the Equator, where probably not more than 3,000 pairs nest on Hood Island.

albatross: The black-footed albatross (Diomedea nigripes), one of three North Pacific species, has a wingspread to about 200 cm (6.5 feet) and is largely sooty brown in colour. It nests on tropical Pacific islands and wanders widely throughout the North Pacific.

albatross, (family Diomedeidae), any of more than a dozen species of large seabirds that collectively make up the family Diomedeidae (order Procellariiformes). Because of their tameness on land, many albatrosses are known by the common names mollymawk (from the Dutch for “foolish gull”) and gooney.

Diomedes, in Greek legend, the son of Tydeus, the Aetolian hero who was one of the Seven Against Thebes. Diomedes was the commander of 80 Argive ships and one of the most respected leaders in the Trojan War. His famous exploits include the wounding of Aphrodite, the slaughter of Rhesus and his

Fenestella: >Diomedes.

Dion was the brother-in-law of Dionysius I, tyrant of Syracuse, in Sicily; Dion was master of Syracuse intermittently between 357 and 354. When Dionysius II, who was weak and inexperienced, succeeded his father in 367, Dion assumed control and persuaded Plato, whose friendship he had acquired, to

Dion and the Belmonts, American rock-and-roll singing group popular in the late 1950s whose lead singer was a successful soloist in the 1960s. The original members were Dion DiMucci (b. July 18, 1939, New York City, New York, U.S.), Angelo D’Aleo (b. February 3, 1940, New York City, New York), Fred

Dio Cassius was a Roman administrator and historian, the author of Romaika, a history of Rome, written in Greek, that is a most important authority for the last years of the republic and the early empire. The son of Cassius Apronianus, governor of Dalmatia and Cilicia under Marcus Aurelius, and

Céline Dion is a French Canadian pop singer, known for her vocal prowess and her passionate showmanship, who achieved international superstardom in the 1990s. Working primarily in the pop ballad tradition, she recorded numerous hit albums in both French and English and was the recipient of several

Céline Dion is a French Canadian pop singer, known for her vocal prowess and her passionate showmanship, who achieved international superstardom in the 1990s. Working primarily in the pop ballad tradition, she recorded numerous hit albums in both French and English and was the recipient of several

Stéphane Dion is a Canadian politician who was the leader of the Liberal Party (2007–08). Dion was the son of one of the cofounders of Laval University’s political science department. He grew up during a period known as “the Quiet Revolution,” when Quebec’s francophone majority was agitating for

Venus flytrap, (Dionaea muscipula), perennial carnivorous plant of the sundew family (Droseraceae), notable for its unusual habit of catching and digesting insects and other small animals. The only member of its genus, the plant is native to a small region of North and South Carolina, where it is

Dione, fourth nearest of the major regular moons of Saturn. It was discovered by the Italian-born French astronomer Gian Domenico Cassini in 1684 and named for a daughter of the Titan Oceanus in Greek mythology. Dione has a diameter of 1,120 km (696 miles) and revolves around Saturn in a prograde,

Dione, in Greek mythology, a consort and, at Dodona in Epirus, a cult partner of Zeus, the king of the gods. Since the partner and wife of Zeus was normally the goddess Hera, it has been conjectured that Dione is an older figure than Hera. Dione was variously described. In the Iliad she is

Dionisy was one of the foremost painters of the medieval principality of Muscovy, who determined the style of the last great era of old Russian art. Though he was celebrated during his lifetime as Muscovy’s leading artist, little is known about his life. Given the many contradictory accounts in

Dionne quintuplets, the five daughters—Émilie, Yvonne, Cécile, Marie, and Annette—born prematurely on May 28, 1934, near Callander, Ontario, Canada, to Oliva and Elzire Dionne. The parents had 14 children, 9 by single births. The quintuplets became international celebrities during their early

Bacchanalia, in Greco-Roman religion, any of the several festivals of Bacchus (Dionysus), the wine god. They probably originated as rites of fertility gods. The most famous of the Greek Dionysia were in Attica and included the Little, or Rustic, Dionysia, characterized by simple, old-fashioned

Bacchanalia, in Greco-Roman religion, any of the several festivals of Bacchus (Dionysus), the wine god. They probably originated as rites of fertility gods. The most famous of the Greek Dionysia were in Attica and included the Little, or Rustic, Dionysia, characterized by simple, old-fashioned

Nonnus: His chief work is the Dionysiaca, a hexameter poem in 48 books; its main subject, submerged in a chaos of by-episodes, is the expedition of the god Dionysus to India. Nonnus’ fertile inventiveness and felicitous descriptive fantasy, which are well served by a unique command of the language and his…

Dionysian, characteristic of the god Dionysus or the cult of worship of Dionysus; specifically, of a sensuous, frenzied, or orgiastic character. The philosopher Friedrich Nietzsche used the terms Dionysian and Apollonian to analyze and explain the character of Greek tragedy in his book The Birth of

Dionysian period, in the Julian calendar, a period of 532 years covering a complete cycle of New Moons (19 years between occurrences on the same date) and of dominical letters—i.e., correspondences between days of the week and of the month, which recur every 28 years in the same order. The product

irrationalism: …is usually assessed as rationalistic—a Dionysian (i.e., instinctive) strain can be discerned in the works of the poet Pindar, in the dramatists, and even in such philosophers as Pythagoras and Empedocles and in Plato. In early modern philosophy—even during the ascendancy of Cartesian rationalism—Blaise Pascal turned from reason to an…

canon law: Development of canon law in the West: …I a completed Dionysiana, the Dionysiana-Hadriana, which was accepted at a national synod in Aachen in 802 but was never adopted as an official national code. About 800 the Hadriana and the Hispana were developed into a systematic whole, the Dacheriana (canonical collection named for its 17th-century publisher, French scholar…

Dionysius of Halicarnassus was a Greek historian and teacher of rhetoric whose history of Rome is, with Livy’s, the most valuable source from early Roman history. This work, called Rhōmaïke archaiologia (Roman Antiquities), treats Rome from its origins to the First Punic War. Though clearly written

Jacob Bar Salibi was the great spokesman of the Jacobite (miaphysite) church in the 12th century. A native of Melitene (now Malatya, Turkey), Bar Salibi was made bishop of Marash in 1154 and, a year later, of Mabbog as well. In 1166 he was transferred to the metropolitan see of Amid (Diyarbakır),

Dionysius Exiguus was a celebrated 6th-century canonist who is considered the inventor of the Christian calendar, the use of which spread through the employment of his new Easter tables. The 6th-century historian Cassiodorus calls him a monk, but tradition refers to him as an abbot. He arrived in

Dionysius I was the tyrant of Syracuse from 405 who, by his conquests in Sicily and southern Italy, made Syracuse the most powerful Greek city west of mainland Greece. Although he saved Greek Sicily from conquest by Carthage, his brutal military despotism harmed the cause of Hellenism. After

Dionysius II, ruler of Syracuse, in Sicily, 367–357 and 346–344 bc. Dionysius was the son and successor of Dionysius I, but he lacked the vigour to maintain the military autocracy he had inherited. Upon his accession in 367 he made peace with Carthage on the same unfavourable terms established

Greece: The role of the Orthodox church: …half of the 17th century Dionysius IV Mouselimis was elected patriarch at least five times. It was this kind of behaviour that prompted an 18th-century Armenian chronicler to taunt the Greeks that they changed their patriarch more frequently than they changed their shirt.

Longinus is sometimes assigned as the author of On the Sublime (Greek Peri Hypsous), one of the great seminal works of literary criticism. The earliest surviving manuscript, from the 10th century, first printed in 1554, ascribes it to Dionysius Longinus. Later it was noticed that the index to the

St. Dionysius of Alexandria ; feast day November 17) was the bishop of Alexandria, then the most important Eastern see, and a chief opponent of Sabellianism. A Christian convert, Dionysius studied in Alexandria at the catechetical school headed by Origen, whom in 231/232 he was elected to succeed.

Dionysius of Halicarnassus was a Greek historian and teacher of rhetoric whose history of Rome is, with Livy’s, the most valuable source from early Roman history. This work, called Rhōmaïke archaiologia (Roman Antiquities), treats Rome from its origins to the First Punic War. Though clearly written

Hadrian: Artistic achievements of Hadrian: Of two eminent orators, Dionysius of Miletus and Favorinus of Arelate (in Gaul), Hadrian openly favoured and advanced the former; he then tried to overthrow him. Favorinus was living in exile toward the end of Hadrian’s reign. The emperor’s tastes dominated the world.

Dionysius Telmaharensis was a patriarch of the Syrian Jacobite church and author of an important source document on Eastern Christianity between the reigns of the Byzantine emperors Mauricius (582–602) and Theophilus (829–842). After some years as a monk in Syria, Dionysius was chosen patriarch and

Dionysius Telmaharensis was a patriarch of the Syrian Jacobite church and author of an important source document on Eastern Christianity between the reigns of the Byzantine emperors Mauricius (582–602) and Theophilus (829–842). After some years as a monk in Syria, Dionysius was chosen patriarch and

Dionysius The Areopagite was a biblical figure, converted by St. Paul at Athens (Acts 17:34), who acquired a notable posthumous reputation primarily through confusion with later Christians similarly named. In the 2nd century he was held to have been the first bishop of Athens, and in the 9th

Dionysius the Carthusian was a theologian and mystic, one of the important contributors to, and propagators of, the influential school of Rhenish spirituality originating in the 14th century. Educated at the University of Cologne, Dionysius entered the Carthusian order at the charterhouse of

Dionysius I was the tyrant of Syracuse from 405 who, by his conquests in Sicily and southern Italy, made Syracuse the most powerful Greek city west of mainland Greece. Although he saved Greek Sicily from conquest by Carthage, his brutal military despotism harmed the cause of Hellenism. After

St. Dionysius of Alexandria ; feast day November 17) was the bishop of Alexandria, then the most important Eastern see, and a chief opponent of Sabellianism. A Christian convert, Dionysius studied in Alexandria at the catechetical school headed by Origen, whom in 231/232 he was elected to succeed.

Pseudo-Dionysius the Areopagite was probably a Syrian monk who, known only by his pseudonym, wrote a series of Greek treatises and letters for the purpose of uniting Neoplatonic philosophy with Christian theology and mystical experience. These writings established a definite Neoplatonic trend in a

Dionysius II, ruler of Syracuse, in Sicily, 367–357 and 346–344 bc. Dionysius was the son and successor of Dionysius I, but he lacked the vigour to maintain the military autocracy he had inherited. Upon his accession in 367 he made peace with Carthage on the same unfavourable terms established

education: Secondary education: …a slim grammatical treatise by Dionysius Thrax. The program then consisted of the seven liberal arts: the three literary arts of grammar, rhetoric, and dialectic and the four mathematical disciplines noted above. (These were, respectively, the trivium and the quadrivium of medieval education, though the latter term did not appear…

St. Denis ; feast day: Western church, October 9; Eastern church, October 3) was allegedly the first bishop of Paris, a martyr and a patron saint of France. St. Denis is also venerated as one of the 14 Holy Helpers, an assemblage of saints who were especially popular in the Middle Ages for their

St. Dionysius ; feast day December 6) was the pope from 259/260 to December 26, 268. While a presbyter during the pontificate of Pope Stephen I (254–257), he took part in the controversy on rebaptism of converts and received an appeal from St. Dionysius the Great, bishop of Alexandria, to avoid a

Dionysus, in Greco-Roman religion, a nature god of fruitfulness and vegetation, especially known as a god of wine and ecstasy. The occurrence of his name on a Linear B tablet (13th century bce) shows that he was already worshipped in the Mycenaean period, although it is not known where his cult

Theatre of Dionysus, prototype of Greek theatres, situated on the south side of the Acropolis in Athens, in which all extant classical Greek plays were first presented. Development on the site began with the creation of the orchestra, a circular floor of earth 60 feet in diameter with an altar at

Pericles: …of Tarsus, and his wife, Dionyza.

Dioon, genus of 10 species of cycads in the family Zamiaceae, native to Mexico and Central America. The spiny-leaved slow-growing giant dioon (Dioon spinulosum) may attain a height of 15 metres (about 50 feet). It is a popular houseplant and is grown outdoors as an ornamental in warmer climates.

Dioon: The spiny-leaved slow-growing giant dioon (Dioon spinulosum) may attain a height of 15 metres (about 50 feet). It is a popular houseplant and is grown outdoors as an ornamental in warmer climates. Starch like that of arrowroot is obtained from the seeds of the chestnut dioon (D. edule).

Alioune Diop was a Senegalese politician, publisher, and founder of the newspaper Présence Africaine. French-educated and a Roman Catholic, Diop served as Senegalese representative in the French Senate from 1946 to 1948 and came into contact with leading French and Francophone African

Birago Diop was a Senegalese poet and recorder of traditional folktales and legends of the Wolof people. Diop received his education in Dakar and Saint-Louis, Senegal, and then studied veterinary medicine at the University of Toulouse until 1933. This was followed by a series of tours as government

Afrocentrism: History: … in 1966; the Senegalese scientist Cheikh Anta Diop, who wrote about the cultural unity of Africa, the African nature of Egyptian civilization, and the “theft” of African civilization by Europeans; and the African American historian Carter G. Woodson, who emphasized the teaching of African history as a way of counteracting…

David Diop was one of the most talented of the younger French West African poets of the 1950s, whose tragic death in an airplane crash cut short a promising career. Diop’s works in Coups de pilon (1956; “Pounding”), his only surviving collection, are angry poems of protest against European cultural

Issa Rae is an American writer, actress, and producer best known for her Web series The Misadventures of Awkward Black Girl (2011–13) and her HBO television series Insecure (2016–21), both of which explore the experience of being a young Black woman in America. Jo-Issa Rae Diop is one of five

Diophantine equation, equation involving only sums, products, and powers in which all the constants are integers and the only solutions of interest are integers. For example, 3x + 7y = 1 or x2 − y2 = z3, where x, y, and z are integers. Named in honour of the 3rd-century Greek mathematician

Diophantus was a Greek mathematician, famous for his work in algebra. What little is known of Diophantus’s life is circumstantial. From the appellation “of Alexandria” it seems that he worked in the main scientific centre of the ancient Greek world; and because he is not mentioned before the 4th

Diophantus was a Greek mathematician, famous for his work in algebra. What little is known of Diophantus’s life is circumstantial. From the appellation “of Alexandria” it seems that he worked in the main scientific centre of the ancient Greek world; and because he is not mentioned before the 4th

stalk-eyed fly, (family Diopsidae), any member of a family of unusual-looking flies (order Diptera) that have their eyes mounted on long stalks near the antennae. This arrangement, although advantageous to vision, is an aerodynamic handicap. The adults of the one species in North America

diopside, common silicate mineral in the pyroxene family that occurs in metamorphosed siliceous limestones and dolomites and in skarns (contact-metamorphic rocks rich in iron); it is also found in small amounts in many chondrite meteorites. Clear specimens of good green colour are sometimes cut as

pyroxene: Chemical composition: …greater than that of the diopside-hedenbergite join, the part of this system below this join is known as the pyroxene quadrilateral. Ferrous iron and magnesium substitute freely since they have similar ionic sizes and identical charges. Complete substitution exists between enstatite (Mg2Si2O6) and ferrosilite (Fe2Si2O6), and complete solid solution of…

diopter, in optics, unit of magnifying power of a lens or lens system. Because the power of a lens is proportional to unity (one) divided by the focal length (see lens), the power of a lens in diopters is numerically equal to 1 m divided by the focal length in metres. The algebraic sign of the

Heron of Alexandria: …contains a description of the diopter, a surveying instrument used for the same purposes as the modern theodolite. The treatise also contains applications of the diopter to measuring celestial distances and describes a method for finding the distance between Alexandria and Rome from the difference between local times at which…

Heron of Alexandria: …to these works is the Dioptra, a book on land surveying; it contains a description of the diopter, a surveying instrument used for the same purposes as the modern theodolite. The treatise also contains applications of the diopter to measuring celestial distances and describes a method for finding the distance…

Heron of Alexandria: …contains a description of the diopter, a surveying instrument used for the same purposes as the modern theodolite. The treatise also contains applications of the diopter to measuring celestial distances and describes a method for finding the distance between Alexandria and Rome from the difference between local times at which…