Chapter IX: Part 9

In Anglo-Saxon and early English poetic literature, and especially in the religious part of it, an element of didacticism is not to be overlooked. But it would be difficult to say that anything of importance was written in verse with the sole purpose of imparting information, until we reach the 16th century. Some of the later medieval allegories are didactic or nothing. The first poem, however, which we can in any reasonable way compare with the classic works of which we have been speaking is the _Hundreth Pointes of Good Husbandrie_, published in 1557 by Thomas Tusser; these humble Georgics aimed at a practical description of the whole art of English farming. Throughout the early part of the 17th century, when our national poetry was in its most vivid and brilliant condition, the last thing a poet thought of doing was the setting down of scientific facts in rhyme. We come across, however, one or two writers who were as didactic as the age would permit them to be, Samuel Daniel with his philosophy, Fulke Greville, Lord Brooke with his "treatises" of war and monarchy. After the Restoration, as the lyrical element rapidly died out of English poetry, there was more and more room left for educational rhetoric in verse. The poems about prosody, founded upon Horace, and signed by John Sheffield, 3rd earl of Mulgrave (1648-1721), and Lord Roscommon, were among the earliest purely didactic verse-studies in English. John Philips deserves a certain pre-eminence, as his poem called Cyder, in 1706, set the fashion which lasted all down the 18th century, of writing precisely in verse about definite branches of industry or employment. None of the greater poets of the age of Anne quite succumbed to the practice, but there is a very distinct flavour of the purely didactic about a great deal of the verse of Pope and Gay. In such productions as Gilbert West's (1703-1756) _Education_, Dyer's _Fleece_, and Somerville's _Chase_, we see technical information put forward as the central aim of the poet. Instead of a passionate pleasure, or at least an uplifted enthusiasm, being the poet's object, he frankly admits that, first and foremost, he has some facts about wool or dogs or schoolmasters which he wishes to bring home to his readers, and that, secondly, he consents to use verse, as brilliantly as he can, for the purpose of gilding the pill and attracting an unwilling attention. As we descend the 18th century, these works become more and more numerous, and more dry, especially when opposed by the descriptive and rural poets of the school of Thomson, the poet of _The Seasons_. But Thomson himself wrote a huge poem of _Liberty_ (1732), for which we have no name if we must not call it didactic. Even Gray began, though he failed to finish, a work of this class, on _The Alliance of Education and Government_. These poems were discredited by the publication of _The Sugar-Cane_ (1764), a long verse-treatise about the cultivation of sugar by negroes in the West Indies, by James Grainger (1721-1766), but, though liable to ridicule, such versified treatises continued to appear. Whether so great a writer as Cowper is to be counted among the didactic poets is a question on which readers of _The Task_ may be divided; this poem belongs rather to the class of descriptive poetry, but a strong didactic tendency is visible in parts of it. Perhaps the latest frankly educational poem which enjoyed a great popularity was _The Course of Time_ by Robert Pollok (1798-1827), in which a system of Calvinistic divinity is laid down with severity and in the pomp of blank verse. This kind of literature had already been exposed, and discouraged, by the teaching of Wordsworth, who had insisted on the imperative necessity of charging all poetry with imagination and passion. Oddly enough, _The Excursion_ of Wordsworth himself is perhaps the most didactic poem of the 19th century, but it must be acknowledged that his influence, in this direction, was saner than his practice. Since the days of Coleridge and Shelley it has been almost impossible to conceive a poet of any value composing in verse a work written with the purpose of inculcating useful information.

The history of didactic poetry in France repeats, in great measure, but in drearier language, that of England. Boileau, like Pope, but with a more definite purpose as a teacher, offered instruction in his _Art poetique_ and in his _Epistles_. But his doctrine was always literary, not purely educational. At the beginning of the 18th century, the younger Racine (1692-1763) wrote sermons in verse, and at the close of it the Abbe Delille (1738-1813) tried to imitate Virgil in poems about horticulture. Between these two there lies a vast mass of verse written for the indulgence of intellect rather than at the dictates of the heart; wherever this aims at increasing knowledge, it at once becomes basely and flatly didactic. There is nothing in French literature of the transitional class that deserves mention beside _The Task_ or _The Excursion_.

During the century which preceded the Romantic revival of poetry in Germany, didactic verse was cultivated in that country on the lines of imitation of the French, but with a greater dryness and on a lower level of utility. Modern German literature began with Martin Opitz (1597-1639) and the Silesian School, who were in their essence rhetorical and educational, and who gave their tone to German verse. Albrecht von Haller (1708-1777) brought a very considerable intellectual force to bear on his huge poems, _The Origin of Evil_, which was theological, and _The Alps_ (1729), botanical and topographical. Johann Peter Uz (1720-1796) wrote a _Theodicee_, which was very popular, and not without dignity. Johann Jacob Dusch (1725-1787) undertook to put _The Sciences_ into the eight books of a great didactic poem. Tiedge (1752-1840) was the last of the school; in a once-famous _Urania_, he sang of God and Immortality and Liberty. These German pieces were the most unswervingly didactic that any modern European literature has produced. There was hardly the pretence of introducing into them descriptions of natural beauty, as the English poets did, or of grace and wit like the French. The German poets simply poured into a lumbering mould of verse as much solid information and direct instruction as the form would hold.

Didactic poetry has, in modern times, been antipathetic to the spirit of the Latin peoples, and neither Italian nor Spanish literature has produced a really notable work in this class. An examination of the poems, ancient and modern, which have been mentioned above, will show that from primitive times there have been two classes of poetic work to which the epithet didactic has been given. It is desirable to distinguish these a little more exactly. One is the pure instrument of teaching, the poetry which desires to impart all that it knows about the growing of cabbages or the prevention of disasters at sea, the revolution of the planets or the blessings of inoculation. This is didactic poetry proper, and this, it is almost certain, became irrevocably obsolete at the close of the 18th century. No future Virgil will give the world a second _Georgics_. But there is another species which it is very improbable that criticism has entirely dislodged; that is the poetry which combines, with philosophical instruction, an impetus of imaginative movement, and a certain definite cultivation of fire and beauty. In hands so noble as those of Lucretius and Goethe this species of didactic poetry has enriched the world with durable masterpieces, and, although the circle of readers which will endure scientific disquisition in the bonds of verse grows narrower and narrower, it is probable that the great poet who is also a great thinker will now and again insist on being heard. In Sully-Prudhomme France has possessed an eminent writer whose methods are directly instructive, and both _La Justice_ (1878) and _Le Bonheur_ (1888) are typically didactic poems. Perhaps future historians may name these as the latest of their class. (E. G.)

DIDEROT, DENIS (1713-1784), French man of letters and encyclopaedist, was born at Langres on the 5th of October 1713. He was educated by the Jesuits, like most of those who afterwards became the bitterest enemies of Catholicism; and, when his education was at an end, he vexed his brave and worthy father's heart by turning away from respectable callings, like law or medicine, and throwing himself into the vagabond life of a bookseller's hack in Paris. An imprudent marriage (1743) did not better his position. His wife, Anne Toinette Champion, was a devout Catholic, but her piety did not restrain a narrow and fretful temper, and Diderot's domestic life was irregular and unhappy. He sought consolation for chagrins at home in attachments abroad, first with a Madame Puisieux, a fifth-rate female scribbler, and then with Sophie Voland, to whom he was constant for the rest of her life. His letters to her are among the most graphic of all the pictures that we have of the daily life of the philosophic circle in Paris. An interesting contrast may be made between the Bohemianism of the famous English literary set who supped at the Turk's Head with the Tory Johnson and the Conservative Burke for their oracles, and the Bohemianism of the French set who about the same time dined once a week at the baron D'Holbach's, to listen to the wild sallies and the inspiring declamations of Diderot. For Diderot was not a great writer; he stands out as a fertile, suggestive and daring thinker, and a prodigious and most eloquent talker.

Diderot's earliest writings were of as little importance as Goldsmith's _Enquiry into the State of Polite Learning_ or Burke's _Abridgement of English History_. He earned 100 crowns by translating Stanyan's _History of Greece_ (1743); with two colleagues he produced a translation of James's _Dictionary of Medicine_ (1746-1748) and about the same date he published a free rendering of Shaftesbury's _Inquiry Concerning Virtue and Merit_ (1745), with some original notes of his own. With strange and characteristic versatility, he turned from ethical speculation to the composition of a volume of stories, the _Bijoux indiscrets_ (1748), gross without liveliness, and impure without wit. In later years he repented of this shameless work, just as Boccaccio is said in the day of his grey hairs to have thought of the sprightliness of the _Decameron_ with strong remorse. From tales Diderot went back to the more congenial region of philosophy. Between the morning of Good Friday and the evening of Easter Monday he wrote the _Pensees philosophiques_ (1746), and he presently added to this a short complementary essay on the sufficiency of natural religion. The gist of these performances is to press the ordinary rationalistic objections to a supernatural revelation; but though Diderot did not at this time pass out into the wilderness beyond natural religion, yet there are signs that he accepted that less as a positive doctrine, resting on grounds of its own, than as a convenient point of attack against Christianity. In 1747 he wrote the _Promenade du sceptique_, a rather poor allegory--pointing first to the extravagances of Catholicism; second, to the vanity of the pleasures of that world which is the rival of the church; and third, to the desperate and unfathomable uncertainty of the philosophy which professes to be so high above both church and world.

Diderot's next piece was what first introduced him to the world as an original thinker, his famous _Lettre sur les aveugles_ (1749). The immediate object of this short but pithy writing was to show the dependence of men's ideas on their five senses. It considers the case of the intellect deprived of the aid of one of the senses; and in a second piece, published afterwards, Diderot considered the case of a similar deprivation in the deaf and dumb. The _Lettre sur les sourds et muets_, however, is substantially a digressive examination of some points in aesthetics. The philosophic significance of the two essays is in the advance they make towards the principle of Relativity. But what interested the militant philosophers of that day was an episodic application of the principle of relativity to the master-conception of God. What makes the _Lettre sur les aveugles_ interesting is its presentation, in a distinct though undigested form, of the modern theory of variability, and of survival by superior adaptation. It is worth noticing, too, as an illustration of the comprehensive freedom with which Diderot felt his way round any subject that he approached, that in this theoretic essay he suggests the possibility of teaching the blind to read through the sense of touch. If the _Lettre sur les aveugles_ introduced Diderot into the worshipful company of the philosophers, it also introduced him to the penalties of philosophy. His speculation was too hardy for the authorities, and he was thrown into the prison of Vincennes. Here he remained for three months; then he was released, to enter upon the gigantic undertaking of his life.

The bookseller Lebreton had applied to him with a project for the publication of a translation into French of Ephraim Chambers's _Cyclopaedia_, undertaken in the first instance by an Englishman, John Mills, and a German, Gottfried Sellius (for particulars see ENCYCLOPAEDIA). Diderot accepted the proposal, but in his busy and pregnant intelligence the scheme became transformed. Instead of a mere reproduction of Chambers, he persuaded the bookseller to enter upon a new work, which should collect under one roof all the active writers, all the new ideas, all the new knowledge, that were then moving the cultivated class to its depths, but still were comparatively ineffectual by reason of their dispersion. His enthusiasm infected the publishers; they collected a sufficient capital for a vaster enterprise than they had at first planned; D'Alembert was persuaded to become Diderot's colleague; the requisite permission was procured from the government; in 1750 an elaborate prospectus announced the project to a delighted public; and in 1751 the first volume was given to the world. The last of the letterpress was issued in 1765, but it was 1772 before the subscribers received the final volumes of the plates. These twenty years were to Diderot years not merely of incessant drudgery, but of harassing persecution, of sufferings from the cabals of enemies, and of injury from the desertion of friends. The ecclesiastical party detested the _Encyclopaedia_, in which they saw a rising stronghold for their philosophic enemies. By 1757 they could endure the sight no longer. The subscribers had grown from 2000 to 4000, and this was a right measure of the growth of the work in popular influence and power. To any one who turns over the pages of these redoubtable volumes now, it seems surprising that their doctrines should have stirred such portentous alarm. There is no atheism, no overt attack on any of the cardinal mysteries of the faith, no direct denunciation even of the notorious abuses of the church. Yet we feel that the atmosphere of the book may well have been displeasing to authorities who had not yet learnt to encounter the modern spirit on equal terms. The _Encyclopaedia_ takes for granted the justice of religious tolerance and speculative freedom. It asserts in distinct tones the democratic doctrine that it is the common people in a nation whose lot ought to be the main concern of the nation's government. From beginning to end it is one unbroken process of exaltation of scientific knowledge on the one hand, and pacific industry on the other. All these things were odious to the old governing classes of France; their spirit was absolutist, ecclesiastical and military. Perhaps the most alarming thought of all was the current belief that the _Encyclopaedia_ was the work of an organized band of conspirators against society, and that a pestilent doctrine was now made truly formidable by the confederation of its preachers into an open league. When the seventh volume appeared, it contained an article on "Geneva," written by D'Alembert. The writer contrived a panegyric on the pastors of Geneva, of which every word was a stinging reproach to the abbes and prelates of Versailles. At the same moment Helvetius's book, _L'Esprit_, appeared, and gave a still more profound and, let us add, a more reasonable shock to the ecclesiastical party. Authority could brook no more, and in 1759 the _Encyclopaedia_ was formally suppressed.

The decree, however, did not arrest the continuance of the work. The connivance of the authorities at the breach of their own official orders was common in those times of distracted government. The work went on, but with its difficulties increased by the necessity of being clandestine. And a worse thing than troublesome interference by the police now befell Diderot. D'Alembert, wearied of shifts and indignities, withdrew from the enterprise. Other powerful colleagues, Turgot among them, declined to contribute further to a book which had acquired an evil fame. Diderot was left to bring the task to an end as he best could. For seven years he laboured like a slave at the oar. He wrote several hundred articles, some of them very slight, but many of them most laborious, comprehensive and ample. He wore out his eyesight in correcting proofs, and he wearied his soul in bringing the manuscript of less competent contributors into decent shape. He spent his days in the workshops, mastering the processes of manufactures, and his nights in reproducing on paper what he had learnt during the day. And he was incessantly harassed all the time by alarms of a descent from the police. At the last moment, when his immense work was just drawing to an end, he encountered one last and crowning mortification: he discovered that the bookseller, fearing the displeasure of the government, had struck out from the proof sheets, after they had left Diderot's hands, all passages that he chose to think too hardy. The monument to which Diderot had given the labour of twenty long and oppressive years was irreparably mutilated and defaced. It is calculated that the average annual salary received by Diderot for his share in the _Encyclopaedia_ was about L120 sterling. "And then to think," said Voltaire, "that an army contractor makes L800 in a day!"

Although the _Encyclopaedia_ was Diderot's monumental work, he is the author of a shower of dispersed pieces that sowed nearly every field of intellectual interest with new and fruitful ideas. We find no masterpiece, but only thoughts for masterpieces; no creation, but a criticism with the quality to inspire and direct creation. He wrote plays--_Le Fils naturel_ (1757) and _Le Pere de famille_ (1758)--and they are very insipid performances in the sentimental vein. But he accompanied them by essays on dramatic poetry, including especially the _Paradoxe sur le comedien_, in which he announced the principles of a new drama,--the serious, domestic, bourgeois drama of real life, in opposition to the stilted conventions of the classic French stage. It was Diderot's lessons and example that gave a decisive bias to the dramatic taste of Lessing, whose plays, and his _Hamburgische Dramaturgie_ (1768), mark so important an epoch in the history of the modern theatre. In the pictorial art, Diderot's criticisms are no less rich, fertile and wide in their ideas. His article on "Beauty" in the _Encyclopaedia_ shows that he had mastered and passed beyond the metaphysical theories on the subject, and the _Essai sur la peinture_ was justly described by Goethe, who thought it worth translating, as "a magnificent work, which speaks even more helpfully to the poet than to the painter, though to the painter too it is as a blazing torch." Diderot's most intimate friend was Grimm, one of the conspicuous figures of the philosophic body. Grimm wrote news-letters to various high personages in Germany, reporting what was going on in the world of art and literature in Paris, then without a rival as the capital of the intellectual activity of Europe. Diderot helped his friend at one time and another between 1759 and 1779, by writing for him an account of the annual exhibitions of paintings. These _Salons_ are among the most readable of all pieces of art criticism. They have a freshness, a reality, a life, which take their readers into a different world from the dry and conceited pedantries of the ordinary virtuoso. As has been said by Sainte-Beuve, they initiated the French into a new sentiment, and introduced people to the mystery and purport of colour by ideas. "Before Diderot," Madame Necker said, "I had never seen anything in pictures except dull and lifeless colours; it was his imagination that gave them relief and life, and it is almost a new sense for which I am indebted to his genius."

Greuze was Diderot's favourite among contemporary artists, and it is easy to see why. Greuze's most characteristic pictures were the rendering in colour of the same sentiment of domestic virtue and the pathos of common life, which Diderot attempted with inferior success to represent upon the stage. For Diderot was above all things interested in the life of men,--not the abstract life of the race, but the incidents of individual character, the fortunes of a particular family, the relations of real and concrete motives in this or that special case. He delighted with the enthusiasm of a born casuist in curious puzzles of right and wrong, and in devising a conflict between the generalities of ethics and the conditions of an ingeniously contrived practical dilemma. Mostly his interest expressed itself in didactic and sympathetic form; in two, however, of the most remarkable of all his pieces, it is not sympathetic, but ironical. _Jacques le fataliste_ (written in 1773, but not published until 1796) is in manner an imitation of _Tristram Shandy_ and _The Sentimental Journey_. Few modern readers will find in it any true diversion. In spite of some excellent criticisms dispersed here and there, and in spite of one or two stories that are not without a certain effective realism, it must as a whole be pronounced savourless, forced, and as leaving unmoved those springs of laughter and of tears which are the common fountain of humour. _Le Neveu de Rameau_ is a far superior performance. If there were any inevitable compulsion to name a masterpiece for Diderot, one must select this singular "farce-tragedy." Its intention has been matter of dispute; whether it was designed to be merely a satire on contemporary manners, or a reduction of the theory of self-interest to an absurdity, or the application of an ironical clincher to the ethics of ordinary convention, or a mere setting for a discussion about music, or a vigorous dramatic sketch of a parasite and a human original. There is no dispute as to its curious literary flavour, its mixed qualities of pungency, bitterness, pity and, in places, unflinching shamelessness. Goethe's translation (1805) was the first introduction of _Le Neveu de Rameau_ to the European public. After executing it, he gave back the original French manuscript to Schiller, from whom he had it. No authentic French copy of it appeared until the writer had been nearly forty years in his grave (1823).

It would take several pages merely to contain the list of Diderot's miscellaneous pieces, from an infinitely graceful trifle like the _Regrets sur ma vieille robe de chambre_ up to _Le Reve de D'Alembert_, where he plunges into the depths of the controversy as to the ultimate constitution of matter and the meaning of life. It is a mistake to set down Diderot for a coherent and systematic materialist. We ought to look upon him "as a philosopher in whom all the contradictions of the time struggle with one another" (Rosenkranz). That is to say, he is critical and not dogmatic. There is no unity in Diderot, as there was in Voltaire or in Rousseau. Just as in cases of conduct he loves to make new ethical assumptions and argue them out as a professional sophist might have done, so in the speculative problems as to the organization of matter, the origin of life, the compatibility between physiological machinery and free will, he takes a certain standpoint, and follows it out more or less digressively to its consequences. He seizes a hypothesis and works it to its end, and this made him the inspirer in others of materialist doctrines which they held more definitely than he did. Just as Diderot could not attain to the concentration, the positiveness, the finality of aim needed for a masterpiece of literature, so he could not attain to those qualities in the way of dogma and system. Yet he drew at last to the conclusions of materialism, and contributed many of its most declamatory pages to the _Systeme de la nature_ of his friend D'Holbach,--the very Bible of atheism, as some one styled it. All that he saw, if we reduce his opinions to formulae, was motion in space: "attraction and repulsion, the only truth." If matter produces life by spontaneous generation, and if man has no alternative but to obey the compulsion of nature, what remains for God to do?

In proportion as these conclusions deepened in him, the more did Diderot turn for the hope of the race to virtue; in other words, to such a regulation of conduct and motive as shall make us tender, pitiful, simple, contented. Hence his one great literary passion, his enthusiasm for Richardson, the English novelist. Hence, also, his deepening aversion for the political system of France, which makes the realization of a natural and contented domestic life so hard. Diderot had almost as much to say against society as even Rousseau himself. The difference between them was that Rousseau was a fervent theist. The atheism of the Holbachians, as he called Diderot's group, was intolerable to him; and this feeling, aided by certain private perversities of humour, led to a breach of what had once been an intimate friendship between Rousseau and Diderot (1757). Diderot was still alive when Rousseau's _Confessions_ appeared, and he was so exasperated by Rousseau's stories about Grimm, then and always Diderot's intimate, that in 1782 he transformed a life of Seneca, that he had written four years earlier, into an _Essai sur les regnes de Claude et de Neron_ (1778-1782), which is much less an account of Seneca than a vindication of Diderot and Grimm, and is one of the most rambling and inept productions in literature. As for the merits of the old quarrel between Rousseau and Diderot, we may agree with the latter, that too many sensible people would be in the wrong if Jean Jacques was in the right.

Varied and incessant as was Diderot's mental activity, it was not of a kind to bring him riches. He secured none of the posts that were occasionally given to needy men of letters; he could not even obtain that bare official recognition of merit which was implied by being chosen a member of the Academy. The time came for him to provide a dower for his daughter, and he saw no other alternative than to sell his library. When the empress Catherine of Russia heard of his straits, she commissioned an agent in Paris to buy the library at a price equal to about L1000 of English money, and then handsomely requested the philosopher to retain the books in Paris until she required them, and to constitute himself her librarian, with a yearly salary. In 1773 Diderot started on an expedition to thank his imperial benefactress in person, and he passed some months at St Petersburg. The empress received him cordially. The strange pair passed their afternoons in disputes on a thousand points of high philosophy, and they debated with a vivacity and freedom not usual in courts. "_Fi, donc,_" said Catherine one day, when Diderot hinted that he argued with her at a disadvantage, "_is there any difference among men?_" Diderot returned home in 1774. Ten years remained to him, and he spent them in the industrious acquisition of new knowledge, in the composition of a host of fragmentary pieces, some of them mentioned above, and in luminous declamations with his friends. All accounts agree that Diderot was seen at his best in conversation. "He who only knows Diderot in his writings," says Marmontel, "does not know him at all. When he grew animated in talk, and allowed his thoughts to flow in all their abundance, then he became truly ravishing. In his writings he had not the art of ensemble; the first operation which orders and places everything was too slow and too painful to him." Diderot himself was conscious of the want of literary merit in his pieces. In truth he set no high value on what he had done. It is doubtful whether he was ever alive to the waste that circumstance and temperament together made of an intelligence from which, if it had been free to work systematically, the world of thought had so much to hope. He was one of those simple, disinterested and intellectually sterling workers to whom their own personality is as nothing in presence of the vast subjects that engage the thoughts of their lives. He wrote what he found to write, and left the piece, as Carlyle has said, "on the waste of accident, with an ostrich-like indifference." When he heard one day that a collected edition of his works was in the press at Amsterdam, he greeted the news with "peals of laughter," so well did he know the haste and the little heed with which those works had been dashed off.

Diderot died on the 30th of July 1784, six years after Voltaire and Rousseau, one year after his old colleague D'Alembert, and five years before D'Holbach, his host and intimate for a lifetime. Notwithstanding Diderot's peals of laughter at the thought, an elaborate and exhaustive collection of his writings in twenty stout volumes, edited by MM. Assezat and Tourneux, was completed in 1875-1877.

AUTHORITIES.--Studies on Diderot by Scherer (1880); by E. Faguet
(1890); by Sainte-Beuve in the _Causeries du lundi_; by F. Brunetiere
in the _Etudes critiques_, 2nd series, may be consulted. In English,
Diderot has been the subject of a biography by John Morley [Viscount
Morley of Blackburn] (1878). See also Karl Rosenkranz, _Diderots Leben
und Werke_ (1866). For a discussion of the authenticity of the
posthumous works of Diderot see R. Dominic in the _Revue des deux
mondes_ (October 15, 1902). (J. Mo.)

DIDIUS SALVIUS JULIANUS, MARCUS, Roman emperor for two months (March 28-June 2) during the year A.D. 193. He was the grandson of the famous jurist Salvius Julianus (under Hadrian and the Antonines), and the son of a distinguished general, who might have ascended the throne after the death of Antoninus Pius, had not his loyalty to the ruling house prevented him. Didius filled several civil and military offices with distinguished success, but subsequently abandoned himself to dissipation. On the death of Pertinax, the praetorian guards offered the throne to the highest bidder. Flavius Sulpicianus, the father-in-law of Pertinax and praefect of the city, had already made an offer; Didius, urged on by the members of his family, his freedmen and parasites, hurried to the praetorian camp to contend for the prize. He and Sulpicianus bid against each other, and finally the throne was knocked down to Didius. The senate and nobles professed their loyalty; but the people made no attempt to conceal their indignation at this insult to the state, and the armies of Britain, Syria and Illyricum broke out into open revolt. Septimius Severus, the commander of the Pannonian legions, was declared emperor and hastened by forced marches to Italy. Didius, abandoned by the praetorians, was condemned and executed by order of the senate, which at once acknowledged Severus.

AUTHORITIES.--Dio Cassius lxxiii. 11-17, who was actually in Rome at
the time; Aelius Spartianus, _Didius Julianus_; Julius Capitolinus,
_Pertinax_; Herodian ii.; Aurelius Victor, _De Caesaribus_, 19;
Zosimus i. 7; Gibbon, _Decline and Fall_, chap. 5.

DIDO, or ELISSA, the reputed founder of Carthage (q.v.), in Africa, daughter of the Tyrian king Metten (Mutto, Methres, Belus), wife of Acerbas (more correctly Sicharbas; Sychaeus in Virgil), a priest of Hercules. Her husband having been slain by her brother Pygmalion, Dido fled to Cyprus, and thence to the coast of Africa, where she purchased from a local chieftain Iarbas a piece of land on which she built Carthage. The city soon began to prosper and Iarbas sought Dido's hand in marriage, threatening her with war in case of refusal. To escape from him, Dido constructed a funeral pile, on which she stabbed herself before the people (Justin xviii. 4-7). Virgil, in defiance of the usually accepted chronology, makes Dido a contemporary of Aeneas, with whom she fell in love after his landing in Africa, and attributes her suicide to her abandonment by him at the command of Jupiter (_Aeneid_, iv.). Dido was worshipped at Carthage as a divinity under the name of Caelestis, the Roman counterpart of Tanit, the tutelary goddess of Carthage. According to Timaeus, the oldest authority for the story, her name was Theiosso, in Phoenician Helissa, and she was called Dido from her wanderings, Dido being the Phoenician equivalent of [Greek: planetis] (_Etymologicum Magnum_, s.v.); some modern scholars, however, translate the name by "beloved." Timaeus makes no mention of Aeneas, who seems to have been introduced by Naevius in his _Bellum Poenicum_, followed by Ennius in his _Annales_.

For the variations of the legend in earlier and later Latin authors,
see O. Rossbach in Pauly-Wissowa's _Realencyclopadie_, v. pt. 1
(1905); O. Meltzer's _Geschichte der Karthager_, i. (1879), and his
article in Roscher's _Lexikon der Mythologie_.

DIDON, HENRI (1840-1900), French Dominican, was born at Trouvet, Isere, on the 17th of March 1840. He joined the Dominicans, under the influence of Lacordaire, in 1858, and completed his theological studies at the Minerva convent at Rome. The influence of Lacordaire was shown in the zeal displayed by Didon in favour of a reconciliation between philosophy and science. In 1871 his fame had so much grown that he was chosen to deliver the funeral oration over the murdered archbishop of Paris, Monseigneur G. Darboy. He also delivered some discourses at the church of St Jean de Beauvais in Paris on the relations between science and religion; but his utterances, especially on the question of divorce, were deemed suspicious by his superiors, and his intimacy with Claude Bernard the physiologist was disapproved. He was interdicted from preaching and sent into retirement at the convent of Corbara in Corsica. After eighteen months he emerged, and travelled in Germany, publishing an interesting work upon that country, entitled _Les Allemands_ (English translation by R. Ledos de Beaufort, London, 1884). On his return to France in 1890 he produced his best known work, _Jesus-Christ_ (2 vols., Paris), for which he had qualified himself by travel in the Holy Land. In the same year he became director of the College Albert-le-Grand at Arcueil, and founded three auxiliary institutions, Ecole Lacordaire, Ecole Laplace and Ecole St Dominique. He wrote, in addition, several works on educational questions, and augmented his fame as an eloquent preacher by discourses preached during Lent and Advent. He died at Toulouse on the 13th of March 1900.

See the biographies by J. de Romano (1891), and A. de Coulanges
(Paris, 1900); and especially the work of Stanislas Reynaud, entitled
_Le Pere Didon, sa vie et son oeuvre_ (Paris, 1904).

DIDOT, the name of a family of learned French printers and publishers. FRANCOIS DIDOT (1689-1757), founder of the family, was born at Paris. He began business as a bookseller and printer in 1713, and among his undertakings was a collection of the travels of his friend the Abbe Prevost, in twenty volumes (1747). It was remarkable for its typographical perfection, and was adorned with many engravings and maps. FRANCOIS AMBROISE DIDOT (1730-1804), son of Francois, made important improvements in type-founding, and was the first to attempt printing on vellum paper. Among the works which he published was the famous collection of French classics prepared by order of Louis XVI. for the education of the Dauphin, and the folio edition of _L'Art de verifier les dates_. PIERRE FRANCOIS DIDOT (1732-1795), his brother, devoted much attention to the art of type-founding and to paper-making. Among the works which issued from his press was an edition in folio of the _Imitatio Christi_ (1788). HENRI DIDOT (1765-1852), son of Pierre Francois, is celebrated for his "microscopic" editions of various standard works, for which he engraved the type when nearly seventy years of age. He was also the engraver of the _assignats_ issued by the Constituent and Legislative Assemblies and the Convention. DIDOT SAINT-LEGER, second son of Pierre Francois, was the inventor of the paper-making machine known in England as the Didot machine. PIERRE DIDOT (1760-1853), eldest son of Francois Ambroise, is celebrated as the publisher of the beautiful "Louvre" editions of Virgil, Horace and Racine. The Racine, in three volumes folio, was pronounced in 1801 to be "the most perfect typographical production of all ages." FIRMIN DIDOT (1764-1836), his brother, second son of Francois Ambroise, sustained the reputation of the family both as printer and type-founder. He revived (if he did not invent--a distinction which in order of time belongs to William Ged) the process of stereotyping, and coined its name, and he first used the process in his edition of Callet's _Tables of Logarithms_ (1795), in which he secured an accuracy till then unattainable. He published stereotyped editions of French, English and Italian classics at a very low price. He was the author of two tragedies--_La Reine de Portugal_ and _La Mort d'Annibal_; and he wrote metrical translations from Virgil, Tyrtaeus and Theocritus. AMBROISE FIRMIN DIDOT (1790-1876) was his eldest son. After receiving a classical education, he spent three years in Greece and in the East; and on the retirement of his father in 1827 he undertook, in conjunction with his brother Hyacinthe, the direction of the publishing business. Their greatest undertaking was a new edition of the _Thesaurus Graecae linguae_ of Henri Estienne, under the editorial care of the brothers Dindorf and M. Hase (9 vols., 1855-1859). Among the numerous important works published by the brothers, the 200 volumes forming the _Bibliotheque des auteurs grecs_, _Bibliotheque latine_, and _Bibliotheque francaise_ deserve special mention. Ambroise Firmin Didot was the first to propose (1823) a subscription in favour of the Greeks, then in insurrection against Turkish tyranny. Besides a translation of Thucydides (1833), he wrote the articles "Estienne" in the _Nouvelle Biographie generale_, and "Typographie" in the _Ency. mod._, as well as _Observations sur l'orthographie francaise_ (1867), &c. In 1875 he published a very learned and elaborate monograph on Aldus Manutius. His collection of MSS., the richest in France, was said to have been worth, at the time of his death, not less than 2,000,000 francs.

DIDRON, ADOLPHE NAPOLEON (1806-1867), French archaeologist, was born at Hautvillers, in the department of Marne, on the 13th of March 1806. At first a student of law, he began in 1830, by the advice of Victor Hugo, a study of the Christian archaeology of the middle ages. After visiting and examining the principal churches, first of Normandy, then of central and southern France, he was on his return appointed by Guizot secretary to the Historical Committee of Arts and Monuments (1835); and in the following years he delivered several courses of lectures on Christian iconography at the Bibliotheque Royale. In 1839 he visited Greece for the purpose of examining the art of the Eastern Church, both in its buildings and its manuscripts. In 1844 he originated the _Annales archeologiques_, a periodical devoted to his favourite subject, which he edited until his death. In 1845 he established at Paris a special archaeological library, and at the same time a manufactory of painted glass. In the same year he was admitted to the Legion of Honour. His most important work is the _Iconographie chretienne_, of which, however, the first portion only, _Histoire de Dieu_ (1843), was published. It was translated into English by E. J. Millington. Among his other works may be mentioned the _Manuel d'iconographie chretienne grecque et latine_ (1845), the _Iconographie des chapiteaux du palais ducal de Venise_ (1857), and the _Manuel des objets de bronze et d'orfevrerie_ (1859). He died on the 13th of November 1867.

DIDYMI, or DIDYMA (mod. _Hieronta_), an ancient sanctuary of Apollo in Asia Minor situated in the territory of Miletus, from which it was distant about 10 m. S. and on the promontory Poseideion. It was sometimes called _Branchidae_ from the name of its priestly caste which claimed descent from Branchus, a youth beloved by Apollo. As the seat of a famous oracle, the original temple attracted offerings from Pharaoh Necho (in whose army there was a contingent of Milesian mercenaries), and the Lydian Croesus, and was plundered by Darius of Persia. Xerxes finally sacked and burnt it (481 B.C.) and exiled the Branchidae to the far north-east of his empire. This exile was believed to be voluntary, the priests having betrayed their treasures to the Persian; and on this belief Alexander the Great acted 150 years later, when, finding the descendants of the Branchidae established in a city beyond the Oxus, he ordered them to be exterminated for the sin of their fathers (328). The celebrated cult-statue of Apollo by Canachus, familiar to us from reproductions on Milesian coins, was also carried to Persia, there to remain till restored by Seleucus I. in 295, and the oracle ceased to speak for a century and a half. The Milesians were not able to undertake the rebuilding till about 332 B.C., when the oracle revived at the bidding of Alexander. The work proved too costly, and despite a special effort made by the Asian province nearly 400 years later, at the bidding of the emperor Caligula, the structure was never quite finished: but even as it was, Strabo ranked the Didymeum the greatest of Greek temples and Pliny placed it among the four most splendid and second only to the Artemisium at Ephesus. In point of fact it was a little smaller than the Samian Heraeum and the temple of Cybele at Sardis, and almost exactly the same size as the Artemisium. The area covered by the platform measures roughly 360 X 160 ft.

When Cyriac of Ancona visited the spot in 1446, it seems that the temple was still standing in great part, although the _cella_ had been converted into a fortress by the Byzantines: but when the next European visitor, the Englishman Dr Pickering, arrived in 1673, it had collapsed. It is conjectured that the cause was the great earthquake of 1493. The Society of Dilettanti sent two expeditions to explore the ruins, the first in 1764 under Richard Chandler, the second in 1812 under Sir Wm. Gell; and the French "Rothschild Expedition" of 1873 under MM. O. Rayet and A. Thomas sent a certain amount of architectural sculpture to the Louvre. But no excavation was attempted till MM. E. Pontremoli and B. Haussoullier were sent out by the French Schools of Rome and Athens in 1895. They cleared the western facade and the _prodomos_, and discovered inscriptions giving information about other parts which they left still buried. Finally the site was purchased by, and the French rights were ceded to, Dr Th. Wiegand, the German explorer of Miletus, who in 1905 began a thorough clearance of what is incomparably the finest temple ruin in Asia Minor.

The temple was a decastyle peripteral structure of the Ionic order, standing on seven steps and possessing double rows of outer columns 60 ft. high, twenty-one in each row on the flanks. It is remarkable not only for its great size, but (_inter alia_) for (1) the rich ornament of its column bases, which show great variety of design; (2) its various developments of the Ionic capital, e.g. heads of gods, probably of Pergamene art, spring from the "eyes" of the volutes with bulls' heads between them; (3) the massive building two storeys high at least, which served below for _prodomos_, and above for a dispensary of oracles ([Greek: chresmographia] mentioned in the inscriptions) and a treasury; two flights of stairs called "labyrinths" in the inscriptions, led up to these chambers; (4) the pylon and staircase at the west; (5) the frieze of Medusa heads and foliage. Two outer columns are still erect on the north-east flank, carrying their entablature, and one of the inner order stands on the south-west. The fact that the temple was never finished is evident from the state in which some bases still remain at the west. There were probably no pedimental sculptures. A sacred way led from the temple to the sea at Panormus, which was flanked with rows of archaic statues, ten of which were excavated and sent to the British Museum in 1858 by C. T. Newton. Fragments of architectural monuments, which once adorned this road, have also been found. Modern Hieronta is a large and growing Greek village, the only settlement within a radius of several miles. Its harbour is Kovella, distant about 2-1/2 m., and on the N. of the promontory.

See Dilettanti Society, _Ionian Antiquities_, ii. (1821); C. T.
Newton, _Hist. of Discoveries_, &c. (1862) and _Travels in the
Levant_, ii. (1865); O. Rayet and A. Thomas, _Milet et le Golfe
Latmique_ (1877); E. Pontremoli and B. Haussoullier, _Didymes_ (1904).
(D. G. H.)

DIDYMIUM (from the Gr. [Greek: didymos], twin), the name given to the supposed element isolated by C. G. Mosander from cerite (1839-1841). In 1879, however, Lecoq de Boisbaudran showed that Mosander's "didymium" contained samarium; while the residual "didymium," after removal of samarium, was split by Auer v. Welsbach (_Monats. f. Chemie_, 1885, 6, 477) into two components (known respectively as neodymium and praseodymium) by repeated fractional crystallization of the double nitrate of ammonium and didymium in nitric acid. _Neodymium_ (Nd) forms the chief portion of the old "didymium." Its salts are reddish violet in colour, and give a characteristic absorption spectrum. It forms oxides of composition Nd2O3 and Nd2O5, the latter being obtained by ignition of the nitrate (B. Brauner). The atomic weight of neodymium is 143.6 (B. Brauner, _Proc. Chem. Soc._, 1897-1898, p. 70). _Praseodymium_ (Pr) forms oxides of composition Pr2O3, Pr2O5, xH2O (B. Brauner), and Pr4O7. The peroxide, Pr4O7, forms a dark brown powder, and is obtained by ignition of the oxalate or nitrate. The sesquioxide, Pr2O3, is obtained as a greenish white mass by the reduction of the peroxide. The salts of praseodymium are green in colour, and give a characteristic spark spectrum. The atomic weight of praseodymium is 140.5.

DIDYMUS (?309-?394), surnamed "the Blind," ecclesiastical writer of Alexandria, was born about the year 309. Although he became blind at the age of four, before he had learned to read; he succeeded in mastering the whole circle of the sciences then known; and on entering the service of the Church he was placed at the head of the Catechetical school in Alexandria, where he lived and worked till almost the close of the century. Among his pupils were Jerome and Rufinus. He was a loyal follower of Origen, though stoutly opposed to Arian and Macedonian teaching. Such of his writings as survive show a remarkable knowledge of scripture, and have distinct value as theological literature. Among them are the _De Trinitate_, _De Spiritu Sancto_ (Jerome's Latin translation), _Adversus Manichaeos_, and notes and expositions of various books, especially the Psalms and the Catholic Epistles.

See Migne, _Patrol. Graec._ xxxix.; O. Bardenhewer, _Patrologie_, pp.
290-293 (Freiburg, 1894).

DIDYMUS CHALCENTERUS (c. 63 B.C.-A.D. 10), Greek scholar and grammarian, flourished in the time of Cicero and Augustus. His surname (Gr. [Greek: Chalkenteros], brazen-bowelled) came from his indefatigable industry; he was said to have written so many books (more than 3500) that he was unable to recollect their names ([Greek: bibliolathas]). He lived and taught in Alexandria and Rome, where he became the friend of Varro. He is chiefly important as having introduced Alexandrian learning to the Romans. He was a follower of the school of Aristarchus, upon whose recension of Homer he wrote a treatise, fragments of which have been preserved in the Venetian Scholia. He also wrote commentaries on many other Greek poets and prose authors. In his work on the lyric poets he treated of the various classes of poetry and their chief representatives, and his lists of words and phrases (used in tragedy and comedy and by orators and historians), of words of doubtful meaning, and of corrupt expressions, furnished the later grammarians with valuable material. His activity extended to all kinds of subjects: grammar (orthography, inflexions), proverbs, wonderful stories, the law-tablets ([Greek: axones]) of Solon, stones, and different kinds of wood. His polemic against Cicero's _De republica_ (Ammianus Marcellinus xxii. 16) provoked a reply from Suetonius. In spite of his stupendous industry, Didymus was little more than a compiler, of little critical judgment and doubtful accuracy, but he deserves recognition for having incorporated in his numerous writings the works of earlier critics and commentators.

See M. W. Schmidt, _De Didymo Chalcentero_ (1853) and _Didymi
Chalcenteri fragmenta_ (1854); also F. Susemihl, _Geschichte der
griech. Literatur in der Alexandrinerzeit_, ii. (1891); J. E. Sandys,
_History of Classical Scholarship_, i. (1906).

DIE, a town of south-eastern France, capital of an arrondissement in the department of Drome, 43 m. E.S.E. of Valence on the Paris-Lyon railway. Pop. (1906) 3090. The town is situated in a plain enclosed by mountains on the right bank of the Drome below its confluence with the Meyrosse, which supplies power to some of the industries. The most interesting structures of Die are the old cathedral, with a porch of the 11th century supported on granite columns from an ancient temple of Cybele; and the Porte St Marcel, a Roman gateway flanked by massive towers. The Roman remains also include the ruins of aqueducts and altars. Die is the seat of a sub-prefect, and of a tribunal of first instance. The manufactures are silk, furniture, cloth, lime and cement, and there are flour and saw mills. Trade is in timber, especially walnut, and in white wine known as _clairette de Die_. The mulberry is largely grown for the rearing of silkworms. Under the Romans, Die (_Dea Augusta Vocontiorum_) was an important colony. It was formerly the seat of a bishopric, united to that of Valence from 1276 to 1687 and suppressed in 1790. Previous to the revocation of the edict of Nantes in 1685 it had a Calvinistic university.

DIE (Fr. _de_, from Lat. _datum_, given), a word used in various senses, for a small cube of ivory, &c. (see DICE), for the engraved stamps used in coining money, &c., and various mechanical appliances in engineering. In architecture a "die" is the term used for the square base of a column, and it is applied also to the vertical face of a pedestal or podium.

The fabrics known as "dice" take their name from the rectangular form of the figure. The original figures would probably be perfectly square, but to-day the same principle of weaving is applied, and the name dice is given to all figures of rectangular form. The different effects in the adjacent squares or rectangles are due to precisely the same reasons as those explained in connexion with the ground and the figure of damasks. The same weaves are used in both damasks and dices, but simpler weaves are generally employed for the commoner classes of the latter. The effect is, in every case, obtained by what are technically called warp and weft float weaves. The illustration B shows the two double damask weaves arranged to form a dice pattern, while A shows a similar pattern made from two four-thread twill weaves. C and D represent respectively the disposition of the threads in A and B with the first pick, and the solid marks represent the floats of warp. The four squares, which are almost as pronounced in the cloth as those of a chess-board, may be made of any size by repeating each weave for the amount of surface required. It is only in the finest cloths that the double damask weaves B are used for dice patterns, the single damask weaves and the twill weaves being employed to a greater extent. This class of pattern is largely employed for the production of table-cloths of lower and medium qualities. The term damask is also often applied to cloths of this character, and especially so when the figure is formed by rectangles of different sizes.