Dionysius, surnamed THRAX ('the Thracian'), a native of Alexandria, who taught at Rhodes and at Rome about 100 B.C. His Techne Grammatike is the foundation of all subsequent European works on grammar. The best edition is that of Uhlig (Leip. 1884). ionysius OF ALEXANDRIA, | There are editions by Reiske (1774-76), Schwartz often surnamed 'the Great,' was (1877), and Jacoby (2 vols. 1885-88). the greatest pupil of Origen, succeeded Heraclas as head of the Catechists' school in 232, became Bishop of Alexandria in 247, was banished during the persecutions of Decius (250) and Valerian (257), and died in 264. He distinguished himself by his wisdom and moderation in the great church controversies of his time, on the Novatian schism, on the baptism of heretics, on Chiliasm, and on the heresies of the Sabellians and Paul of Samosata. He was distinguished also as an exegete; the Apocalypse he refused to assign to the Apostle John on grounds which show that he possessed the critical faculty as well as an independent mind. Of his numerous writings only a few fragments remain; these were collected by Routh in vols. i. and iv. of his Reliquiæ Sacræ (Oxford, 1814), and in vol. x. of Mai's Auctores Classici (Rome, 1838). See Dittrich, Dionysius der Grosse (1867), and Morize, Denis d'Alexandrie (1881). 50 B.C. Dionysius OF HALICARNASSUS, a learned critic, historian, and rhetorician, was born about He came to Rome about 29 B.C., and lived there on terms of intimacy with many distinguished contemporaries till his death, 7 B.C. His most valuable work is unquestionably his Greek Archaologia, a history of Rome down to 264 B.C., a mine of information about the constitution, religion, history, laws, and private life of the Romans. Of the twenty books of which it originally consisted, we possess only the first nine in a complete form, the tenth and eleventh nearly so, coming down but to 441 B.C.; of the rest, only a few fragments are extant. He was a greater rhetorician and critic than historian, and his extant works on oratory, on the criticism in detail of the great Greek orators, on the characteristics of poets and historians from the time of Homer to Euripides, and upon Thucydides and Dinarchus, possess great interest and value. Dionysius THE AREOPAGITE (i.e. member of the Areopagus, q.v.), one of the few Athenians who, according to Acts, xvii. 34, were converted by the preaching of the Apostle Paul. A later tradition makes him the first Bishop of Athens, and a martyr of the church. The celebrated Greek writings which bear his name, and, connecting Neoplatonism with Christianity, laid the foundation for the mystical theology of the church, were not written by him, but attributed to him after a fashion not uncommon in antiquity. They are first mentioned in 533, when they were appealed to by the Monophysite sect of the Severians against the authority of the Council of Chalcedon. From the 6th century they were generally accepted as genuine, and exercised a very great influence on the development of theology. They include writings On the Heavenly Hierarchy, On the Ecclesiastical Hier archy, On Divine Names, On Mystical Theology, and a series of ten Epistles. In the Western Church they are first referred to in one of the Homilies of Gregory the Great. In the 9th century Erigena, at Charles the Bald's command, prepared an annotated Latin translation; and he and many of the scholastic theologians who followed him drew much of their inspiration from this source. The date assigned to the pseudo-Dionysian writings is fixed by Kanakis as early as 120, by Frothingham as late as 520. Harnack holds that it has not yet been decided at what period between 350 and 500 they were written, and adheres provisionally to the second half of the 4th century, with a final recension about the year 500. This great unknown thinker was probably an Alexandrian. His fundamental thought is the a molute transeescence of God, which he attemp Dionysius the Elder, tyrant of Syracuse, was terrible rock-hewn dungeon called Lastumia. In 36% be renewed the war with the Carthaginians, who'n he wished to drive out of Sicily altogether, bat died suddenly next year, not without a sus pleion that his physician had hastened nature to make favour with his son. Dionysins was a most vigorous but unscrupulous ruler. His last years were tormented with an excessive dread of treachery. succeeded his father in 367 B.C., and celebrated his Dionysius the Younger, son of the preceding, accession by a splendid festival, which lasted ninety days. His political education had been designedly neglected by his father, and in conse"quence he grew up an indolent, pleasure-loving, and dissolute prince. Dion (q.v.), who was at once his father's son-in-law and brother-in-law, sought to improve him by the instructions of Plato, but his torian, who disgracefully encouraged the excesses endeavours were frustrated by Philistns, the his of the youth. Dion was banished, but afterwards returning to Sicily, expelled Dionysius from Syracuse in 356. The latter fled to Locri, the birthplace of his mother, Doris, where he was hospitably received. He repaid the kindness of the Locrians by making himself master of their city, which he ruled despotically for several years. In 346 the internal dissensions of Syracuse enabled him to return thither, and here he ruled for three years until Timoleon came from Corinth to free Sicily. Dionysius soon had to surrender, and was allowed to spend the rest of his life at Corinth, where he haunted low company, spent his means, and had to keep a school for bread. Dionysius Exiguus (or the Little'), so named either from his small stature, or by his own monkish humility, was a Scythian by birth, and became abbot of a monastery at Rome, where he He was one of the most learned men died in 556. of his time, translated various theological writings from Greek into Latin, and is especially noted for his fixing of the Christian era (see CHRONOLOGY), and his collection of canons. See CANON LAW. Dionysus. The worship of Dionysus, who was originally the god of vegetation, and not till after the time of Homer the god of wine, was borrowed by the Greeks from the Thracians. When adopted as a Greek god he was naturally made the son of Zeus, the sky from which falls the rain that makes the vegetation grow. His mother, Semele, was destroyed before his birth through her own folly in begging the sky-god to visit her in all his majesty of thunder and lightning. As the remainder of the period of gestation was accomplished in the thigh of Zeus, the paternity of Dionysus was made doubly sure by the myth, and Dionysus was called the twice born.' The spread of the worship of the god is mirrored in myths which represent him as bestowing blessings on those who accepted him, and madness on those who, like Lycurgus and Pentheus, resisted him. The peculiar characteristic of the cult is that it is orgiastic. Of the orgies as they were actually celebrated we may form an idea from the way in which at the present day in France (on the jour des brandons) the peasants carry torches, and utter loud cries, for the purpose of insuring fertility in vineyard and orchard; and in South Germany they dance and leap and make every kind of noise in order to rouse the corn,' 'to wake the spring' the madder the dance and the cries, the more effectual the invocation. In mythology the orgies' are imagined as being performed by Manades, Bacchantes, and others, who in their ecstasies rend animals to pieces, as they rush with their torches by night over the land. Part of the cult of Dionysus consisted in eating oxen and goats, which were regarded as the incar DIOÖN nation of the generative power of which Dionysus was the god. Mythology makes Dionysus himself, under the name of Zagreus, to have been devoured by the Titans; his heart alone was saved, and he was born again as the son of Semele. The orgiastic worship of Dionysus explains the fact that wine when it became known was regarded as the gift of Dionysus (see BACCHUS).-The Dionysia were festivals held in his honour throughout Greece. In Attica alone there were four Dionysia at different seasons of the year-the most important, the Lenca, celebrated with a procession and scenic contests in tragedy and comedy, out of which grew all the glories of the Greek drama. Dioön. See CYCADS. Diophantus, one of the last of the great Greek mathematicians, lived at Alexandria, most probably in the second half of the 3d century of our era. He died at the age of eighty-four. The titles of three of his works are Arithmetics, Polygonal Numbers, and Porisms. Of the first, which consisted of thirteen books, only six remain; of the second we possess merely a fragment; and the third has been entirely lost. The Arithmetics is the earliest extant treatise on algebra, but it would be rash to say that Diophantus was the inventor of algebra, though to what extent he was indebted to his predecessors cannot now be decided. The first book of the Arithmetics is occupied with problems leading to determinate equations of the first degree, the rest of the books with problems leading to indeterminate equations of the second degree, the sixth book in particular being devoted to the finding of right-angled triangles where some linear or quadratic function of the sides is to be a square or a cube. The treatise on Polygonal Numbers is not analytical but synthetical-i.e. in the manner of Euclid's arithmetical books-and in it numbers are represented by lines. The Porisms were probably a collection of propositions on the properties of certain numbers. The first translation of Diophantus was into Latin by Xylander (Wilhelm Holzmann) in 1575. The only edition of the Greek text is that by Bachet, published along with a Latin translation in 1621, and reprinted with the addition of Fermat's notes and many misprints in 1670. A translation into German by Otto Schulz appeared in 1822. See T. L. Heath's Diophantos of Ålexandria (1885). DIOPHANTINE ANALYSIS, so called from Diophantus, is that part of algebra which treats of the finding of particular rational values for general expressions under a surd form. A simple example of a diophantine problem is to find a right-angled triangle whose three sides are expressible by xr + yn = rational numbers, or in other words, to divide a square number into two squares (Diophantus, Arithmetics, ii. 9). A diophantine theorem less simple is the statement of Fermat, which even yet has only been partially proved, that the equation z" is impossible for every integral value of n greater than 2. The diophantine analysis is really a part of what is now called the theory of numbers, and its development is to be sought in the writings of those mathematicians, from Fermat and Euler downwards, who have cultivated this subject. Much information regarding it will be found in the second part of Euler's Algebra. Dioptrics is that branch of geometrical optics which treats of the transmission of rays of light from one medium into another differing in kind. It consists of the results of the application of geometry to ascertain in particular cases the action of what are called the laws of refraction. OPTICS. Diorama. See PANORAMA. See Dioscorea'ceæ, an order of Monocotyledons, of which the genus Dioscorea (see YAM) is the type. There are about 150 species, temperate or tropical, all twining shrubs, with large rootstocks or tubers. Tamus (Testudinaria) elephantipes, a South African species, sometimes called Elephants' Foot, and Hottentots' Bread, has a large fleshy rhizome, with a rough cracked bark, which is used as food by the Hottentots in times of scarcity. Its congener, T. communis (Black Bryony), is the only British representative of the order. Diosco'ridés, PEDACIUS, or PEDANIUS, a Greek physician, was a native of Anazarba, in Cilicia, and, probably in the 2d century of our era, accompanied the Roman armies as physician through many countries. He has left a great work on materia medica, in five books, in which he treats of all the then known medicinal substances and their properties, real or reputed. His authority in botany and materia medica was long undisputed, and is still maintained in the East. The best editions of Dioscorides, including some smaller works bearing his name, are by Saracenus (1598) and Sprengel (2 vols. 1829-30). Dioscuri. See CASTOR AND POLLUX. Diospyros. See DATE PLUM, and EBONY. Dip, in Geology, is the inclination of strata downwards into the earth. The amount or angle of dip is the degree of deviation from a level line, or the plane of the horizon. See HORIZON. Diphtheria (Gr. diphthera, a pellicle') was described in 1826 by M. Bretonneau of Tours as a form of very fatal sore throat, occurring chiefly in children, and apt to be confounded with Croup (q. v.), with malignant sore throat (Angina Maligna), as it is found in connection with Scarlet Fever (q. v.), and Tonsilitis (see TONSILS.) Diphtheria is distinct from these diseases, not only in the symptoms, but in the character and position of the morbid changes on the mucous membrane. It begins by ache, and more or less fever; soon the throat feels malaise, feeling of chilliness, loss of appetite, headhot and painful, whilst the neck is stiff and tender. If seen early, the throat is red and swollen, but a false membrane of yellowish or grayish colour quickly appears in spreading patches on an inflamed and ulcerated base in the pharynx or back of the throat, and often extends down the œsophagus or gullet, one side usually being more affected than the other. There may be enlargement of the glands at the angle of the jaw, and albuminuria generally occurs at some stage of the disease. After Diphtheritic membrane may be got on any mucous surface, or even on a wound; if it extends into the larynx, it gives rise to cough and often accompanied by a low and very dangerous difficulty in breathing. The throat affection is form of fever, with great and rapid loss of the patient's strength, which is still further reduced by disease is fatal by paralysis of the heart, or by the inability to take food; in other cases, the suffocation, due to invasion of the larynx, when tracheotomy may require to be resorted to. the acute disease is over, the recovery may be delayed by paralytic symptoms of various kinds; or loss of appetite. simply by extreme debility, with exhaustion and the peculiar tendency of tacking itself on to other Diphtheria is contagious, and has diseases, especially scarlet fever, when it assumes a climates seem to favour its development, while the very fatal gangrenous form. Damp and temperate contagium may remain dormant for long periods. Outbreaks have been directly traced to impure drainage and bad water. One attack affords only slight protection against recurrence. The treat ment aims at keeping up the strength of the patient by means of concentrated beef tea, milk, egg-flip, and alcohol. Iron in large doses is most valuable, and sometimes quinine. Locally, solvents, such as lactic acid or lime-water, are applied to the throat by a brush; antiseptics are also useful, the best being Condy's fluid, carbolic acid, and borax. Caustics ought not to be used; cauterisation, formerly in use, being cruel, dangerous, and useless; and the best authorities do not sanction the excision of the diphtheritic membrane. The paralysis may require to be treated with electricity. See GERM THEORY OF DISEASE. Diphthong (Gr., having a double sound') means two vowel-sounds following one another so closely as to form but one syllable, as in out. In this combination the sound is really composed of an a as heard in father, and an u as heard in put. Many double vowels in English are not real diphthongs, there being only one sound heard. The only real diphthongs being i, as in high; i in aye; oi in boil; ow in how; and ew in mew. The spelling of the English language has little or no relation to the pronunciation in this matter. In many syllables written with two vowels, only one sound is heard, as in bread. The single vowel-letters, again, often have a diphthongal sound; thus the long sound of i as in high, is really composed of the sound of a, as heard in father, and that of e in me; and tune is pronounced as if written teun. Such words as bread, field, which are now monophthongs, were doubtless at one time real diphthongs, and are still so pronounced in many parts of England. On the other hand, the ae in such words as aerated is not a diphthong, and to write arated is of course wrong. Diploma (Gr., a paper folded double,' from diploo, I double,' or 'fold '). This term originated in the ancient custom of writing solemn documents on two tablets of wax, which were doubled, or laid one upon the other (see DIPTYCH), or on writing material which was folded. The Roman emperors were in the habit of giving diplomas to public servants, and to couriers, to enable them to procure the use of the public servants and horses; hence diploma came to signify a royal charter or prince's letters-patent. The term is now mostly applied to instruments given by universities and other learned societies, in proof of the holder having attained a certain degree; to the licenses held by physicians and surgeons; and to certificates of merit awarded at exhibitions. Diplomacy is the art of conducting the intercourse and adjusting the mutual relations of nations. The term owes its origin to the ancient use of public documents, known as diplomas, from their being written on two leaves or double tablets. From the point of view of the philosophy of law, diplomacy arises out of the necessary interdepend ence of states. This interdependence being recognised, the rights and duties of political intercourse flow from the rights and duties of recognition; and it is, consequently, from the general doctrines of the recognition of state-existence that the special principles of legation are to be deduced. Recognition implies separate existence, not potential only, but actual, and therefore only states having such separate existence are entitled to express their will through separate diplomatic agents. It is on this ground that the right of legation is denied to colonies, however important or distant from the parent state. A limitation in the rights and duties of legation also arises in the case of semi-barbarous nations, whose municipal law and the judgments of whose courts are not recognised by civilised states. Diplomacy has arisen out of the development of the European powers, and, as a uniform system, it is even now confined chiefly to these powers. Its practical rules are embodied partly in those international customs and usages which constitute what may be called common, and partly in those treaties which may be regarded as statute international law. war. The frequent necessity for rapid decision in this department of politics has compelled even those nations who most jealously guard their constitutional rights to intrust at least provisional power of action to individual rulers. Thus in Britain the sovereign, independently of parliament, has technically the power to make peace and declare The practical guidance of the relations of Britain with foreign states is committed to the Secretary of State for Foreign Affairs and his department. The power, however, of sending ambassadors to, and receiving ambassadors from foreign nations remains an unalienable privilege of the It was doubted whether an exception had not been made in the case of Rome, by the statutes passed against papal encroachments; but such doubts were removed by 11 and 12 Vict. chap. 108, which authorises the sovereign to enter into diplomatic relations, provided that no person in holy orders in the Church of Rome, or Jesuit, or member of any other religious order, community, or society of that church, bound by monastic or religious vows, shall be received as ambassador in London. crown. The existing diplomatic hierarchy, as fixed by the annex to the Treaty of Vienna in 1815, falls into three ranks. (1) Ambassadors, legates, or nuncios, who alone have the representative character; (2) Envoys extraordinary, or ministers plenipotentiary, accredited to sovereigns; (3) Chargés d'Affaires, who are entitled to transact business only with the Minister for Foreign Affairs. Every diplomatic agent must be furnished with a letter of credence stating the general object of his mission, and requesting that full faith and credit be given to what he shall say on behalf of his court. From the moment that a public minister enters the territory of the state to which he is sent, until he leaves the country, he is entitled to an entire exemption from the local jurisdiction, both civil and criminal. An English ambassador, with his family and suite, whilst abroad in the public service, is held to be domiciled in England; his house is on English ground, and he carries the municipal laws of his own state along with him. Debts incurred in his public capacity must be sued for in England, and, in the event of his transgressing the laws of the foreign nation to which he is accredited, he can be dealt with only diplomatically -i.e. England must be called upon to punish him. An ambassador, as representing a sovereign power, ranks in the court to which he is accredited immediately after the princes of the blood-royal. The international law of Europe has attributed to certain states what are called royal honours, which entitle the states by whom they are possessed to precedence over all others who do not enjoy the same rank, along with the exclusive right of sending to other states diplomatic agents of the first rank. Such royal honours are enjoyed by the empires and kingdoms of Europe, and amongst Catholic states by the pope; and the same right extends to the United States of America. Where the rank of different states is equal or undetermined, different expedients have been resorted to for the purpose of avoiding a contest, and at the same time securing the respective rights and pretensions of the parties. This subject was left by the Congress of Vienna on the ancient footing of custom. The most important of these expedients is what is called the alternat, by which the rank and place of the various powers are changed from time to time, either in a certain regular order, or in one determined by lot. Thus, |