Structure of a HexapodStructure of a HexapodA, Head:a, antennæ;b, compound eyes;c, occiput;d, ocelli;e, palpi.B, Thorax:f, pronotum;f1, prothoracic legs;g, mesonotum;g1, mesonotal leg;h, metathorax;h1, metathoracic leg;i, mesothoracic, andj, metathoracic, wings;k, coxa of leg;l, trochanter;m, femur;n, tibia;o, tarsus;p, ungues.C, Abdomen:q, body segments;r, genitalia.
A, Head:a, antennæ;b, compound eyes;c, occiput;d, ocelli;e, palpi.B, Thorax:f, pronotum;f1, prothoracic legs;g, mesonotum;g1, mesonotal leg;h, metathorax;h1, metathoracic leg;i, mesothoracic, andj, metathoracic, wings;k, coxa of leg;l, trochanter;m, femur;n, tibia;o, tarsus;p, ungues.C, Abdomen:q, body segments;r, genitalia.
Entomology
Entomoph´aga('insect eaters'), a term applied to (1) a group of hymenopterous insects whose larvæ feed upon living insects; (2) a tribe of marsupials, as the opossums, bandicoots, &c., which are insectivorous, though not exclusively so; (3) a section of the edentates, as the ant-eater and pangolin.
Entomophthorineæ, a curious family of Fungi, group Zygomycetes, all parasites on insects. The best known isEmpusa Muscæ, which attacks the common house-fly. After thoroughly permeating and finally killing the infected fly, the fungus sends numerous hyphæ to the surface, from the ends of which conidia are shot forth by an 'explosive' process, to spread the infection if they alight on living flies. In autumn, flies killed by this parasite may often be found adhering to window-panes, surrounded by a halo of ejected conidia. It has been proposed to utilize this fungus in combating the fly nuisance.
EntomostracaEntomostracaSpiny-tailed water-flea (Daphnia) on left; Cyclops on right. Both enlarged.
Spiny-tailed water-flea (Daphnia) on left; Cyclops on right. Both enlarged.
Entomos´traca, a sub-class of crustacea, including forms which are mostly small, and comprising four orders: (1) Branchiopoda, brine-shrimps and water-fleas; (2) Copepoda, including the freshwater Cyclops, and numerous marinespecies contributing to the floating surface population (plankton); (3) Cirripedia, barnacles; (4) Ostracoda, types such as Cypris enclosed in a bivalve shell.
EntozoaEntozoa magnified1,Cœnūrus cerebrālis(producing the staggers in sheep).a, Heads (shown on the surface) separately.2,Cysticercus cellulosæ(causing the measles in pigs).b, Head.
1,Cœnūrus cerebrālis(producing the staggers in sheep).a, Heads (shown on the surface) separately.
2,Cysticercus cellulosæ(causing the measles in pigs).b, Head.
Entozo´a, a general name for the various parasitic worms that infest the bodies of other animals. Some are found in the intestines, others in the liver, brain, muscles, and other tissues. They pass through different stages in their development, and at each stage may occupy a different organ (or tissue), and usually a different animal. Thus the cystic or bladder-worm, whose presence in the brain of sheep causes staggers, is the immature form of a tapeworm of the dog, &c. The number of species is being reduced as the relations of the different forms are studied. They belong to the two phyla Platyhelminthes (flat-worms) and Nemathelminthes (thread-worms, &c.). The former embraces flukes (Trematoda) and tapeworms (Cestoda); while the latter includes thread-worms and round-worms (Nematoda), and spiny-headed worms (Acanthocephala).
Entrenchments.The employment of entrenchments, or earthworks, in connection with military operations dates from the earliest times. Entrenched camps, made by the Romans, are still to be seen in many parts of the country. The primary object, in early designs, was to offer a material obstacle to the assaulting enemy; the defenders manned a high parapet overlooking a formidable ditch, and a hand-to-hand conflict decided the issue. The development of fire-arms, and especially of artillery, depreciated the value of entrenchments as affording material obstacles, but gave them a gradually increasing value as a means of protecting the defenders from missiles. The provision of cover, that is to say, concealment from view or protection from fire, ultimately became the dominant factor in the design of earthworks. Obstacles were still necessary, but they had to be provided by other means. Successive improvements in firearms altered the nature of the cover which it was necessary and practicable to provide. A bullet-proof parapet has always been an essential feature, but whereas a few inches of earth sufficed to stop a musket-ball, the modern rifle-bullet will penetrate a thickness of nearly four feet. The introduction, during last century, of shrapnel shell, the bullets from which descend at a steep angle, was followed by the adoption of overhead cover as a standard feature in trench design. This persisted for several years, until the great increase in the power of high-explosive shell made it impossible to construct any form of roof which would withstand bombardment, even by the lighter artillery accompanying an army in the field, and still permit of the defenders using their rifles from below it. Modern fire-positions are made open, i.e. without overhead cover.
All past wars have proved that victory can only be won as the result of offensive action. Nevertheless, in any campaign it will not be possible to attack at all times and in all places. The provision of the strongest possible force at the vital point necessitates a defensive attitude on other parts of the front. Although entrenchments presuppose a defensive attitude locally, they play an important part in offensive operations. The ultimate aim is that, by a skilful use of entrenchments, a commander may be able to reduce to a minimum the strength of his force in actual combat with the enemy, and thus to retain at his disposal a reserve of troops for offensive action.
Entrenchments may be either hasty or deliberate. Hasty entrenchments are those made on the actual field of battle: by the attackers, to secure the ground won prior to another bound forward; by the defenders, to hold up the attack pending fresh dispositions of troops in rear. The amount of digging that can be done is necessarily small; existing cover must be utilized to the utmost. This mayconsistof ditches, hedges, sunken roads, railway embankments and cuttings, buildings, woods, shell-holes, &c. All of these are readily convertible into strong defences. The test of battle has proved, over and over again, that troops well trained in adapting natural cover to defence are very difficult to dislodge, once they have dug themselves in. Deliberate entrenchments are employed in the gradual building up of a trench system when once the opportunity of manœuvre has ceased to exist; or in the preparation of a defensive position somewhat remote from the scene of active operations.
The following are the salient features in the design of modern entrenchments: (1) A parapet 18 inches high, and upwards of 5 feet thick, in front of every fire-trench. (2) Longitudinal division of every trench, either by projecting buttresses of earth or by bends, so that no straight portion exceeds 10 yards in length. The effect of this is to give protection againstflanking or enfilade rifle-fire, and to localize the burst of shell. (3) A parapet on the rear side (parados), to shield the defenders from the back-blast of shell which burst beyond the trench. (4) Wide trenches (6 feet at the top), to minimize the risk of men getting buried during bombardment. (5) Accommodation, in dug-outs and other refuges, for a proportion of the troops.
Arms of precision have, during the past twenty years, compelled careful attention to the concealment of entrenchments. Although systems of trenches cannot now be hidden from the eye of the aeroplane-camera, yet the enemy can be kept in doubt, by correct design and careful siting of trenches, as to the strength in which the various portions of a position are held. It is for this reason that the deep fire-trench, with a low parapet in front, has been universally adopted, despite the obvious objection that minor undulations restrict the field of fire because the rifle is brought nearer to the ground. Earthworks on a sky-line, or those seen by the enemy against a distant background, violate the first principles of siting.
Modern entrenchments are arranged in depth. The 'lines' of Wellington's time have given place to a broad belt of mutually supporting defences, organized in three zones. These merge imperceptibly into one another, and each zone extends upwards of a mile from front to rear. The foremost fringe of the outpost zone is in contact with the enemy; it is the high-water mark on which the troops advancing during the last action have come to a standstill and dug themselves in. Very lightly manned, as befits an area where heavy shelling is rife, this zone, nevertheless, plays an important rôle. It harbours the forward artillery observation posts, which control and direct the fire of the guns in rear. It furnishes a 'jumping-off' place for attacks. It takes the first shock of a hostile attack, and, although not strong enough to repulse a serious offensive, contributes to the enemy's ultimate defeat by depriving his onslaught of momentum. The battle zone is more elaborately organized, and capable of being very heavily manned. Within this area the defence intend to bring to a standstill the most determined offensive. It lies sufficiently far back from the fringe of the outpost zone to be reasonably immune from destructive bombardment. Lying still farther back is the third zone, which serves for the accommodation of reserves of troops, and is also prepared for defence, as a last resort, in case the enemy should penetrate the battle zone.
Entrepôt(a˙n˙-tr-pō; Fr.), a port where foreign merchandise which cannot enter the interior of a country is deposited in magazines under the surveillance of the custom-house officers till it is re-exported; also, any place where goods are sent to be distributed wherever customers are found.
Entre Rios(en´tre rē´os; 'between rivers'), a province of the Argentine Republic, lying between the Uruguay and the Paraná; area estimated at 29,240 sq. miles; pop. 425,370. The province is largely pastoral. Capital, Paraná, with a pop. of 25,000
Entro´pionis the inversion or turning in of the eyelid. It may be congenital, or arise as the result of some inflammatory process or burn of the conjunctiva. Entropion affecting the lower lid appears also as the result of extreme photophobia (intolerance to light).
Entropy, a term introduced into physics by Clausius as the name of one of the two important thermodynamical properties of a substance which depend on its 'state'. Suppose we have 1 lb. of water at atmospheric pressure and 212° F., say, and suppose we apply heat to the water and change it into 1 lb. of steam at 212° F. The temperature does not change during this process, while the heat which must be added is the latent heat of the steam, namely, about 960 British Thermal Units. The increase of entropy from the first state to the second state is got by dividing the heat given to the substance, namely, 960 B.Th.U., by the absolute temperature at which that heat was given to the substance, namely, 461 + 212 = 673 degrees absolute, i.e. the increase of entropy is960/673= 1.43 units. If the temperature changes with the addition of heat, as it would usually do, we have to imagine the heat to be supplied in small quantities, and to take the average temperature of the body at which these tiny quantities of heat are supplied. The quotient heat ÷ temperature is taken for each small quantity of heat, and the results are added together. The summation is defined as the increase in entropy between the initial and the final states.
In mathematical language the increase in entropy between state A and state B is given by (φB-φA) =Definite Integral, whereφstands for the entropy, Q for the heat received by the body, and T for the absolute temperature at which the heat is received. The importance of the entropy function, namely, the integralIndefinite Integral, in thermodynamics is due to the fact that it is, like the internal energy of the substance, a function of the state of the substance only, and consequently in any temperature cyclic change in which the final state of the substance is the same as its initial state A, the total change, either of its internal energy or of its entropy,is zero. The fact that the total change in the internal energy of the substance is zero is practically equivalent to theFirst Law of Thermodynamics, while the fact that the total change of the entropy of the substance is zero is equivalent to theSecond Law of Thermodynamics.—Bibliography: J. H. Poynting and J. J. Thomson,Textbook of Physics(vol. 3):Heat.
En´velopes, the paper covers that enclose letters or notes. They became common shortly after the introduction of the penny postage system; were at first made chiefly by hand, but are now not only shaped, but folded and gummed, by machinery.
Enver Pasha, Turkish soldier and politician, born at Constantinople in 1879. He entered the Turkish army in 1896, and in 1905 took part in the Young Turk movement at Salonica. He joined the revolutionaries in 1908, was for a short time military attaché in Berlin, but in 1909 returned to Salonica, and assisted in the deposition of Sultan Abdul Hamid. He then took part in the Tripoli War and the second Balkan War, and recaptured Adrianople from the Bulgarians in July, 1913. After being Minister of War, Enver subsequently became one of the leaders of the Committee of Union and Progress. A staunch pro-German, he was to a great extent responsible for Turkey's entry into the European War as an ally of Germany. After the armistice of 1918, Enver Pasha fled to the Caucasus, and was active in inciting his countrymen to resist the terms of the Peace Treaty of 1920.
Environment, in biology, the surroundings of an organism, including non-living factors, such as climate and weather; and also other organisms. Plants and animals are more or less adapted to their surroundings, a good example being the mutual adaptations of flowers and insects, but there has been much controversy as to the way in which such adaptations have come about. Among all but unicellular organisms any individual consists of (1) a general body (soma), by which the life of the individual is maintained, and (2) germ cells, capable of becoming fresh individuals, and thus providing for the continuance of the species. According to a school of thought founded by some of the pre-Darwinian evolutionists, notably Buffon, Lamarck, and Treviranus, modifications of the soma (acquired characters) of an individual, brought about by the action of the environment (e.g. thickening of parts of the skin as the result of constant pressure), or by use and disuse (e.g. increased size of muscles; diminished wings of poultry), can be inherited, leading to increasing alteration capable of ending in the production of new species. Most living biologists, however, hold with Weismann that onlygerminal variations, i.e. variations in the substances of the germ-cells, are heritable. Much further research is necessary before it is possible to pronounce with certainty on many of the complex details involved in these theories. As to the part played by the environment, cases are known where this acts directly on the germ-cells, so as to influence their variation. But these are among some of the lower animals, in which the eggs develop outside the body of the parent, and we know hardly anything about the action of the environment on germs that develop internally. It has been suggested that modifications of the soma undoubtedly brought about by the influence of the surroundings may react upon the germ-cells and cause these to vary, but of this no proof has so far been forthcoming. Even if we admit that modifications of the soma are not inherited, they may nevertheless play a part in evolution by aiding the development of germinal variations that take the same direction. The whole subject is one of more than academic interest, especially in regard to the further evolution of human beings. Comparatively rapid advance, either in desirable or undesirable directions, would be possible if modifications acquired by the soma of an individual were capable of being inherited. So far as we know at present, acquired improvements in physique and mentality of individuals are not inherited by their offspring, which seems rather disappointing, but, on the other hand, undesirable modifications, including those due to disease, appear to be in the same case, and there is little reason to think that the children of parents possessing undesirable acquired characters are unduly handicapped from the very start. We must, of course, exclude cases of antenatal infection by the microbes of certain infectious or contagious diseases to which one or both parents have fallen victims, and also those of direct poisoning of germ-cells as the result of alcoholism.
En´voy, a person deputed by a Government to negotiate a treaty,or transact other business, with a foreign Government. We usually apply the word to a public minister sent for one particular purpose; hence anenvoyis distinguished from anambassador, and is of inferior rank.
Enzymes.SeeFermentation,Physiological Chemistry.
Eocene System in EnglandMap of Eocene System in England
E´ocene, in geology, a term applied to the lower division of the Tertiary strata, from Gr. ēōs, dawn, andkainos, recent, because remains of existing organic species first occur here. The Eocene beds are arranged in two groups, termed the Lower and Upper Eocene; the strata formerly called Upper Eocene being now known as Oligocene. They consist of marls, limestones, clays, and sandstones, and are found in the Isle of Wight and in the south-east of England and north-west of France, in Central Europe, WesternAsia, Northern Africa, and the Atlantic coast of North America.
Éon de Beaumont.SeeD'Éon de Beaumont.
E´os, among the ancient Greeks the goddess of the dawn. SeeAurora.
Eötvös(eut´veush), Baron Joseph, a Hungarian statesman and author, born 1813, died 1871. He completed his studies at the University of Pesth in 1831. He had already, before leaving the university, produced three dramas—The Critics,The Wedding, andRevenge—the last a tragedy, all of which were well received. He became a friend of Kossuth, and distinguished himself as a journalist and orator of the popular party. In 1848, after the revolution of 15th March, he was appointed Minister of Public Instruction, resigned the same year, but was again appointed Minister of Public Instruction in 1867, and filled this office until his death. Among his works are the novels:The Carthusian,The Village Notary(translated into English), andHungary in 1514—giving vivid pictures of Hungarian life in modern and more remote epochs.
Eozo´ic Rocks, the name given to the pre-Cambrian rocks, from their containing the first or earliest traces of life in the stratified systems.
Eozo´on, a supposed gigantic fossil foraminifer found in the limestone of the pre-Cambrian rocks of Canada, whence the nameEozoön canadense. The structure, however, which is recognized also in Bavaria and in County Galway, has proved to be due to a zonal development of serpentine during metamorphism of the ancient limestones concerned. A similar structure occurs in limestone associated with the volcanic focus of Vesuvius.
Ep´acris, a genus of gamopetalous Dicotyledons, the typical genus of the nat. ord. Epacridaceæ, distinguished by having a coloured calyx with many bracts, a tubular corolla with smooth limb, stamens affixed to the corolla, and a five-valved many-seeded capsule. The species are shrubby plants, with axillary, white, red, or purple flowers, generally in leafy spikes. Among those cultivated in Britain we may mentionE. grandiflōra, which has flowers nearly an inch in length, of a brilliant reddish purple at the base and pure white at the apex. The order Epacridaceæ consists of plants allied to the heaths, chiefly natives of Australia. The fruit of some species is eaten under the name of Australian cranberry, and they are cultivated in greenhouses for their flowers.
Ep´act(Gr.epaktos, added), in chronology, the excess of the solar month above the lunar synodical month, and of the solar year above the lunar year of twelve synodical months. The epacts then areannualandmenstrualormonthly. Suppose the new moon to be on the 1st of January: the month of January containing 31 days, and the lunar month only 29 days, 12 hours, 44 minutes, 3 seconds; the difference, 1 day, 11 hours, 15 minutes, 57 seconds, is themenstrual epact. Theannual epactis nearly 11 days; the solar year being 365 days, and the lunar year 354. The epacts were once of some importance in ecclesiastical chronology, being used for finding when Easter would fall.
Epaminon´das, an ancient Greek statesman and general, who, for a short time, raised his country, Thebes, to the summit of power and prosperity. He was born about 418B.C., and killed at the battle of Mantinea, 362B.C.He took the leading part in the struggle during which Spartan supremacy in Greece was destroyed, and the supremacy of Thebes temporarily secured. Four times he successfully invaded the Peloponnesus at the head of the Thebans, but after hisdeath Thebes soon sank to her former secondary condition. Throughout life Epaminondas was distinguished for the friendship subsisting between him and Pelopidas, with whom he served in the Spartan campaign, 385B.C.His character is one of the finest recorded in Greek history. and his virtues have been praised by both Xenophon and Plutarch.
Eparch(ep´ärk), in Greece, the governor or prefect of a provincial division called aneparchy, a subdivision of a nomarchy or province of the kingdom. In Russia, an eparchy is the diocese or arch-diocese of a bishop or archbishop of the Greek Church.
Epaulement(e-pa¨l´ment: Fr.épaule, shoulder), in fortification, a term for the mass of earth or other material which protects the guns in a battery in front and on either flank.
Ep´aulet, or Ep´aulette(Fr.épaulette, dim. ofépaule, the shoulder), an ornamental shoulder-piece belonging to a military or other dress. Epaulettes were worn in the British army till 1855, and in the United States as late as 1872, and are still worn in the navy by all officers of and above the rank of lieutenant, and by some civil officers.
Épée(ė-pā), Charles Michel, Abbé de l', French philanthropist, born in 1712, died 1789. He had chosen the clerical profession, but had to leave the Church on account of Jansenist opinions. The great object of his life was the instruction of the deaf and dumb, upon whom he spent his whole income, besides what was contributed by benevolent patrons. In 1770 he founded at his own expense an institution for the deaf and dumb. He left several works on his method of instruction, one of these beingInstitution des sourds et muets(1774).
Épéhy, a town of France, department of Somme, about 13 milesS.E.of Cambrai. It was the scene of fierce fighting during the European War, and was captured by the British in Sept., 1918.
Epeira(e-pī´ra), a genus of spiders, comprising the largest and best-known British species.E. diadēma, the common garden spider, is a handsomely marked species, which constructs a beautifully symmetrical wheel-shaped web.
Eperies(ep´er-yāsh), a town of Czecho-Slovakia, formerly in Hungary, on the Tarcza, the seat of a Greek Catholic bishop. Pop. 16,323.
Épernay(ep-er-nā; ancientSparnacum, and the RomanAquæ Perennes), a town of North-Eastern France, department of Marne, on the Marne, the central depot of the wine trade of Champagne. The vast wine-cellars of the town form a labyrinth of galleries cut in the tufa or calcareous soil of the district. Épernay was occupied for a short time by the Germans at the beginning of the European War, and was one of the enemy's objectives in the second battle of the Marne (July, 1918). Pop. 21,811.
E´phah, orBath, a Hebrew measure of capacity, containing, according to one estimate or calculation, 8.6696 gallons; according to another, only 4.4286 gallons.
Ephedra, the principal genus of the Gnetales family of Gymnosperms. The species are shrubby switch-plants, natives of the warm temperate zone, found especially on sandy soil. The ripe seeding cones have fleshy scales, and those ofE. distachyaare eaten in South Russia.
Ephem´era, the typical genus of the neuropterous insects constituting the family Ephemeridæ, so named from the extreme shortness of their lives in the perfect state. They are known asmay-fliesorday-flies, and are characterized by the slenderness of their bodies; the delicacy of their wings, which are erect and unequal, the anterior being much the larger; the rudimentary condition of the mouth; and the termination of the abdomen in three filiform appendages. In the state of larvæ and pupæ they are aquatic and exist for years. When ready for their final change, they creep out of the water, generally towards sunset of a fine summer evening, beginning to be seen generally in May. They shed their whole skin shortly after leaving the water, propagate their species, and die, taking no food in the perfect state. The may-fly is well known to anglers, who imitate it for bait.
Ephe´sians, The Epistle to the, a canonical epistle addressed by the Apostle Paul to the Church which he had founded at Ephesus. It was written during his first captivity at Rome, immediately after he had written theEpistle to the Colossians(A.D.62); and was sent by the hands of Tychicus, who also bore the message to the Church at Colossæ.
Eph´esus, an ancient Greek city of Lydia, in Asia Minor, one of the twelve Ionian cities, on the south side of the Caystrus, near its mouth. It was at one time the grand emporium of Western Asia, having a convenient and spacious harbour. The Apostle Paul visited Ephesus and established a Christian Church there, to which he dedicated one of his Epistles. It was famous for its temple of Artemis (Diana), calledArtemision, the largest and most perfect model of Ionic architecture, and reckoned one of the seven wonders of the world. The first great temple, begun about 650B.C.and finished after 120 years, was burnt by the notorious Herostratus in order to perpetuate his name, 356B.C.(the night of Alexander the Great's birth). A second and more magnificent was then erected, which was burned by the Goths inA.D.262. Some interesting remains have been discovered by excavation since 1896. Several Church councils were held here, especially the ThirdEcumenical Council of 431, at which Nestorius was condemned. The site of the city is now desolate; near it is a poor village, Aiasoluk.
Eph´od,a species of vestment worn by the Jewish high-priest over the second tunic. It consisted of two main pieces, one covering the back, the other the breast and upper part of the body, fastened together on the shoulders by two onyx stones set in gold, on each of which were engraved the names of six tribes according to their order. A girdle or band, of one piece with the ephod, fastened it to the body. Just above the girdle, in the middle of the ephod, and joined to it by little gold chains, rested the square breastplate with the Urim and Thummim. The ephod was originally intended to be worn by the high-priest exclusively, but a similar vestment of an inferior material seems to have been in common use in later times among the ordinary priests.
Eph´ors,orEph´ori(Gr.ephoroi, overseers), magistrates common to many Dorian communities of ancient Greece, of whom the most celebrated were the Ephori of Sparta. They were five in number, were elected annually, and both the judicial authority and the executive power were almost entirely in their hands. Their power became an intolerable burden, especially to the kings, and in 225B.C.Cleomenes III murdered the whole college and abolished the office.
E´phraem Syrus, that is, 'Ephraim the Syrian', writer of the Syrian Church, born at Nisibis, in Mesopotamia, aboutA.D.306, died at Edessa in 373 or 378. He wrote several commentaries on Scripture, numerous homilies, and other works (as well as hymns), which have come down to us partly in Syriac, partly in Greek, Latin, and Armenian translations. They were edited by Assemani at Rome between 1732 and 1746, and by Overbeck at Oxford in 1865.
E´phraim, the younger son of Joseph, and the founder of one of the twelve tribes of Israel. When the Israelites left Egypt, the Ephraimites numbered 40,500, and their possessions in the very centre of Palestine included most of what was afterwards called Samaria. Ephraim is also a town mentioned inJohn, xi, 54, and to which Jesus retired after His raising of Lazarus, when the Jewish authorities manifested their hostility against Him.
Ep´ic, a poem of the narrative kind, dealing with a series of events or actions of permanent interest. Some authorities restrict the term to narrative poems written in a lofty style and describing the exploits of heroes. Others widen the definition so as to include not only long narrative poems of romantic or supernatural adventure, but also those of an historical, legendary, mock-heroic, or humorous character. Epic poetry is distinguished from drama in so far as the author frequently speaks in his own person as narrator; and from lyrical poetry by making the predominant feature the narration of action rather than the expression of emotion. Among the more famous epics of the world's literature may be noted: Homer'sIliadandOdyssey, Virgil'sÆneid, the GermanNibelungenlied, the Anglo-Saxon poem ofBeowulf, the FrenchSong of Roland, Dante'sDivina Commedia, Tasso'sGerusalemme Liberata, Ariosto'sOrlando Furioso, Milton'sParadise Lost, Spenser'sFaerie Queene, Camoens'Lusiads(Portuguese), and Firdusi'sShah Namah(Persian). Hesiod'sTheogony, theElder Edda, the FinnishKalevala, and the IndianMahâbhâratamay be described as collections of epic legends. The historical epic has an excellent representative in Barbour'sBruce; and specimens of the mock-heroic and humorous epic are found inThe Battle of the Frogs and Mice,Reynard the Fox, Butler'sHudibras, and Pope'sRape of the Lock.—Bibliography: Chassang and Marcou,Les Chefs-d'œuvre épiques de tous les peuples; W. M. Dixon,English Epic and Heroic Poetry; A. Lang,Homer and the Epic.
Epicharmus(ep-i-kär´mus), a Sicilian comic poet and philosopher of the Pythagorean school, born in the Island of Cos about 540B.C., died 450B.C.He removed to Syracuse, where at the court of Hieron he spent the remainder of his life. He is credited with the invention of written comedy, and Plato called him "a master of the comic type".
Epicte´tus, a Greek Stoic philosopher, born at Hierapolis, in Phrygia, aboutA.D.60. He lived long at Rome, where, in his youth, he was a slave. Though nominally a Stoic, he was not interested in Stoicism as an intellectual system; he adopted its terminology and its moral doctrines, but in his discourses he appeared rather as a moral and religious teacher than as a philosopher. His doctrines approach more nearly to Christianity than those of any of the earlier Stoics, and although there is no trace in what is recorded of them of his having been directly acquainted with Christianity, it is at least probable that the ideas diffused by Christian teachers may have indirectly influenced them. The excellence of his system was universally acknowledged. When Domitian banished the philosophers from Rome (A.D.94), Epictetus retired to Epirus, where he is supposed to have died. His disciple Arrian collected his opinions, which are preserved in two treatises called theDiscourses of Epictetus, and theManual or Enchiridion.
Epicu´rus, a Greek philosopher, founder of the Epicurean school, was born in the Island of Samos 342B.C., died at Athens 270B.C.He settled at Athens 306B.C., and purchased a gardenin a favourable situation, where he established a philosophical school. Here he spent the remainder of his life, living in a simple manner and taking no part in public affairs. His pupils were numerous and enthusiastically devoted to him. His theory of the universe was based on the atomic theory of Democritus. The fundamental principle of his ethical system was that pleasure and pain are the chief good and evil, the attainment of the one and the avoidance of the other of which are to be regarded as the end of philosophy. The term 'Epicurean' has come to signify one who is indulging his sensual appetites without measure, but this is really due to a misapprehension of the meaning of the word pleasure as used by the philosopher. Epicurus himself was not an 'Epicurean' in this sense, for he endeavoured to give a moral tendency to this doctrine. He exalted the pure and noble enjoyments derived from virtue, to which he attributed an imperishable existence, as incalculably superior to the passing pleasures which disturb the peace of mind, the highest good, and are therefore detrimental to happiness. Peace of mind, based on meditation, he considered as the origin of all good. It is, however, easy to see that his use of the word 'pleasure' was calculated to produce the mischievous results with which Epicureanism has been charged. The philosophy of Epicurus has, therefore, been violently opposed and frequently misrepresented; but while it is not open to the charges of gross sensualism which have been brought against it, it cannot be considered as much better than a refinement of sensualism. In ancient times his philosophy appears to have been more popular in Greece than in Rome, although his disciples were numerous in both, and the Latin poem of Lucretius,De Rerum Natura, is a poetical exposition of his doctrines. Epicureanism was resuscitated in France by Pierre Gassendi, and its principles have been professed by De la Rochefoucauld, Rousseau, and Voltaire. Epicurus was a very voluminous writer, but few of his writings are extant, what we possess comprising only some fragments of aTreatise on Nature, two letters, and detached passages. Lucretius, Cicero, Pliny, and Diogenes Laertius are our chief authorities for his doctrines.—Bibliography: Lange,History of Materialism; W. Wallace,Epicureanism; Guyau,La Morale d'Epicure; Taylor,Epicurus; W. Pater,Marius the Epicurean.
Ep´icycle, a conception of the ancient astronomy used to explain the irregular, and at times retrograde, motions of the planets. Corresponding to each planet there was supposed to be a circle called adeferent, which had the earth as its centre. Round this circle a point was imagined to revolve with uniform motion. That point formed the centre of a second and smaller circle, called an epicycle, and the actual planet was supposed to revolve with uniform motion round the circumference of the epicycle.
Epicy´cloid, in geometry, a curve generated by a point on the circumference of a circle which rolls on the convex side of another fixed curve. The curve generated by rolling on the concave side is called a 'hypocycloid'. If the point is not on the circumference, the generated curves are called 'trochoids'.
Epicycloidal WheelEpicycloidal Wheel
Epicycloi´dal Wheel, a wheel or ring fixed to a framework, toothed on its inner side, and having in gear with it another toothed wheel of half the diameter of the first, fitted so as to revolve about the centre of the latter. It is used for converting circular into alternate motion, or alternate into circular. While the revolution of the smaller wheel is taking place, any point whatever on its circumference will describe a straight line, or will pass and repass through a diameter of the circle, once during each revolution. In practice, a piston-rod or other reciprocating part may be attached to any point on the circumference of the smaller wheel.
Epidau´rus, a town and seaport of ancient Greece, situated in Argolis, in the Peloponnesus, particularly celebrated for its magnificent temple of Æsculapius, which stood on an eminence not far from the town. It had also temples of Artemis, Dionysus, Aphrodite, and Hera, and a splendid theatre still in fair preservation. The site is now occupied by the villageEpidavro, where a congress met in 1822 and promulgated the 'Constitution of Epidaurus'.
Epidem´ic, orEpidemic Disease(Gr.epi, upon, anddēmos, people), signifies a disease which attacks a people, suddenly spreading from one to the other in all directions, prevailing a certain time and then dying away. It usually travels from place to place in the direction of the most-frequented lines of communication. The reason is that such diseases are commonly due to some infective material capable of beingconveyed from one individual to another, and of being transported from place to place. In Britain smallpox and cholera are occasionally epidemic, whilst scarlet fever, measles, chickenpox, diphtheria, typhoid fever, &c., are almost invariably so. Certain diseases which appear to be more mental than physical sometimes occur so numerously as to assume an epidemic form, such as St. Vitus's dance, convulsionary diseases, or suicidal mania.
Epiden´drum(Gr.epi, upon, anddendron, a tree), a large genus of tropical American orchids, most of the species of which are epiphytic, growing on trees. The flowers are very handsome, and a large number of the species are in cultivation.
Epider´mis, in anatomy, the cuticle or scarf-skin of the body; a thin membrane covering the true skin of animals, consisting of two layers, an inner or mucous layer, called therete mucosum, composed of active cells containing granules of colouring matter, and an outer or horny layer, consisting of flattened scale-like cells, dry, inactive, and effete, which are constantly being shed in the form of dust. Both layers are destitute of blood-vessels or nerves.
EpidermisSurface View of Epidermisst, Stomata.
st, Stomata.
Epidermis, in botany, the superficial layer of cells covering leaves and young stems. Its principal function is to restrict transpiration, for which purpose its outer wall is more or less cutinized, i.e. chemically modified so as to be very impervious to water and gases, especially the outermost part thereof, the so-calledcuticle. Naturally both cuticle and epidermis as a whole are most strongly developed in drought-adapted plants or xerophytes (q.v.); and conversely the epidermis of submerged plants is not cutinized, nor is the superficial layer of ordinary roots. The epidermis frequently bears hairs of various kinds. Stems which undergo secondary growth in thickness soon cast off their epidermis, its rôle being assumed by cork or bark. The water- and gas-proof covering provided by the epidermis is not continuous, but is interrupted by numerous minute pores orstomata, capable of opening and closing, through which accordingly a regulated interchange of gases takes place.
Ep´idote, a mineral of a green or grey colour, vitreous lustre, and partial transparency, a member of the garnet family. The primary form of the crystals is a right rhomboidal prism. The crystals occur in Norway, Siberia, Tyrol, and the United States.
Epigæa(-jē´a), a genus of Ericaceous shrubs.E. repens, the trailing arbutus, is the May-flower of North America.
Epiglottisis a cartilaginous plate behind the tongue, which covers the glottis like a lid during the act of swallowing, and thus prevents foreign bodies from entering the larynx. In its ordinary position during respiration it is pointed upwards, but in the act of swallowing it is pressed downwards and backwards by the drawing up of the windpipe beneath the base of the tongue, and thus closes the entrance to the air-passages. SeeLarynx.
Ep´igram(Gr.epi, upon,graphein, to write), in a restricted sense, a short poem or piece in verse, which has only one subject, and finishes by a witty or ingenious turn of thought; in a general sense, a pointed or witty and antithetical saying. The term was originally given by the Greeks to a poetical inscription placed upon a tomb or public monument, and was afterwards extended to every little piece of verse expressing with precision a delicate or ingenious thought, as the pieces in theGreek Anthology. In Roman classical poetry the term was somewhat indiscriminately used, but the epigrams of Martial contain a great number with the modern epigrammatic character. Epigrams flourished in modern times after the Revival of Learning period, and all the Elizabethan versifiers tried their hand at them. Pope was a great master of the epigram, and the art was practised by Clément Marot, Boileau, Voltaire, Schiller, Goethe, Byron, and Moore, and more recently by Sir William Watson.—Cf. Dodd,Epigrammatists of Mediæval and Modern Times.
Epigraphy, a term used both for the study of inscriptions as a whole, and for the science which deals with their classification and decipherment. The attention of the epigraphist is given to inscriptions upon stone, brick, metal, and other comparatively permanent material, as compared with writings upon parchment, papyrus, or paper; but he excludes inscriptions upon coins, which are in the department of the numismatist. The science of epigraphy is of immense importance for a knowledge of the past, the subjectincluding inscriptions so far apart in point of time as Egyptian records of the days of Mena (4700B.C.), and the Greek hexameters that commemorate the death in Westmorland of a young Syrian soldier in the army of Septimius Severus. Of still more recent date are the Runic inscriptions discovered in Greenland, which seem to place beyond a doubt the fact of Icelandic explorers having reached that country in the eleventh or twelfth century. The most important inscriptions are Egyptian, Cuneiform (Babylonian and Assyrian), Semitic, Greek, Latin, Indian, and Runic. The inscribed writings include epitaphs on the dead, records of important events, dedications of public buildings, with such comparatively private matters as receipts, contracts, and other business transactions. While inscriptions form a valuable source of knowledge, they cannot be accepted as invariably reliable. Reasons might in some cases exist for making a false or misleading record, as in the case of a eulogistic tombstone, while mistakes in spelling and other details may be due to a careless workman. The literature which deals with the science of epigraphy is very large.