DEFILADING

of Voltaire, Montesquieu, D'Alembert, and other great men of letters of her day. In 1753 she became blind, and in the following year she invited Mademoiselle de l'Espinasse to live with her and help her to preside over her salon. The arrange- | ment lasted for ten years, when a quarrel broke out through Madame du Deffand's jealousy, and Mademoiselle de l'Espinasse departed, taking away with her D'Alembert and others of the elder lady's former admirers. From 1766 Madame du Deffand carried on an interesting correspondence with Horace Walpole, who held her in the highest estimation, and pressed the use of his purse on her when she fell into pecuniary troubles. To say nothing of her extraordinary parts,' Walpole wrote, 'she is certainly the most generous friendly being upon earth.' As a matter of fact, however, she was as selfish and spiteful as she was witty and shrewd. She died at Paris, September 24, 1780. See Correspondance de Madame du Deffand (new ed. 5 vols. 1865-67); her Letters to Horace Walpole and Voltaire (4 vols. Lond. 1810); and Asse, Malle. de Lespinasse et la Marquise du Deffand (1877).

Defilading, in Fortification (q.v.), consists in determining the direction and height of the rampart, so that the interior of the work may not be commanded by the fire of the enemy. To prevent the lines being enfiladed, their prolongations must avoid all places where hostile batteries could be posted, and the parapets must be of sufficient height to protect the interior from frontal fire.

Definite Proportions, Laws OF, in Chemistry. See ATOMIC THEORY.

Definition, the process by which we determine the common qualities of the objects belonging to any given class, so as to distinguish effectively that class from other classes. Regarding the class as a species, we give the proximate genus and the difference; genus here denoting the distinctive qualities belonging to all of the genus, while the difference marks out the part of the genus in question. A good definition should state the essential attributes of the species defined, without containing the name itself, and should be exactly equal in denotation with it.

Deflagration is the term applied to the rapid combustion of ignited charcoal when a nitrate (such as nitrate of potash) or a chlorate (such as chlorate of potash) is thrown thereon. As chlorates do not occur naturally, it follows that deflagration with a natural salt indicates a nitrate; and if the deflagration be accompanied by a violet flame, it is characteristic of nitrate of potash (ordinary nitre or saltpetre); and if by a strong yellow flame, it is indicative of nitrate of soda (cubical nitre).

Deflection, in Navigation, the departure of a ship from her true course; in Optics, a deviation of the rays of light toward the surface of an opaque body.

Defluxion (Lat. defluxio), a discharge from a mucous membrane, especially of the air-passages, as in catarrh.

Defoe, DANIEL, immortal as the author of Robinson Crusoe, was born most likely in 1661, in the parish of St Giles, Cripplegate, London. His family belonged originally to Northamptonshire, and his father, James Foe, became a butcher in St Giles's, and was living so late as 1705. It was Daniel who first changed his name to De Foe, or Defoe, about 1703, for unknown reasons. He had a good education at a dissenting academy, but soon abandoned his early idea of becoming a dissenting minister, and engaged in business, apparently as a hose-factor, about the year 1685. Little is known of his early life, but it seems he was out with Mon

mouth, and it is certain that he volunteered into King William's army in 1688, travelled both in France and Spain, and became bankrupt about 1692; his debts, or at least great part of them, he paid up later with a scrupulousness most honourable to him. He next became accountant to the glass-duty commissioners, and secretary to a Tilbury pantile factory. His Essay upon Projects appeared about 1698, and towards the close of William III.'s reign he became noted as an able and busy pamphleteer in support of the king's policy. His vigorous poem, The True-born Englishman, a Satyr (1701), was an attempt to apologise for the king's being a Dutchman by proving the English themselves to be a most composite race. His restless pen was active throughout the bitter struggle under Anne between the High-Church party and the dissenters, and his famous treatise, The Shortest Way with the Dissenters (1703), made him a martyr in the cause. Ostensibly written by a 'high-flyer,' it advocated the extirpation of dissenters with a masterly irony (pace Mr Saintsbury), which at first deceived and then infuriated his opponents, as, in his own words in The Present State of Parties (1712), it 'cut the throat of the whole party.' The House of Commons ordered the book to be burned, and a reward of £50 was offered for his apprehension, from which fortunately we have an exact description of his appearance as a middle-sized, spare man, about forty years old, of a brown complexion, and dark brown-coloured hair, but wears a wig; a hooked nose, a sharp chin, gray eyes, and a large mole near his mouth.' Tried at the Old Bailey in July, he was sentenced to pay a fine of 200 marks, to stand thrice in the pillory, and to be imprisoned during the queen's pleasure. Accordingly, the 'unabashed Defoe' stood in the pillory the last three days of July 1703, in the midst of a sympathetic mob that protected him from insult, and even drank his health. On the same day he suffered appeared his masculine Hymn to the Pillory, which concluded with a noble defiance to the government, expressed in some of his finest lines. During his imprisonment in Newgate he continued an incessant literary activity upon 'occasional conformity' and other points at issue in the great controversy, published a 'true collection' of his writings, and started his Review (19th February 1704-11th June 1713), at first a weekly, after eight numbers a bi-weekly, and after the eighth number of the second volume a tri-weekly newspaper, 'purged from the errors and partiality of newspapers and petty statesmen of all sides.' Defoe's largest, if not his most important work, and indeed forms one of the greatest monuments of literary industry ever reared by a single hand, embracing as it does in more than five thousand printed pages essays on almost every branch of nine years, in which also, according to Mr Lee, he human knowledge, and these written during but published no fewer than eighty distinct works, themselves containing as many as 4727 pages. Its 'Scandal Club,' which discussed minor matters of manners, was distinctly the forerunner of the more famous Tatlers and Spectators.

This was

In August 1704 Defoe was released from prison at the instigation of Harley, who, moreover, procured for him pecuniary relief and employment, thus earning for himself the journalist's unceasing gratitude. After a short stay at Bury St Edmunds, he returned to London, maintaining at both places his activity in his Review, and in such admirable pamphlets as Giving Alms no Charity, and Employing the Poor a Griev ance to the Nation, a masterly denunciation of indiscriminate charity and national workshops-a kind of socialistic scheme propounded by Sir Humphrey Mackworth. Next year (1705) appeared The

DEFORCEMENT

See the Lives by George Chalmers (1786), Walter Wilson (1830), William Chadwick (1859), and William Lee (1869); the studies by Scott, Lamb, Hazlitt, Forster, Leslie Stephen, and Professor Minto. The best approximations to complete editions of Defoe's works have been those of Scott and Hazlitt.

Deforcement, in English law, includes abatement, intrusion, disseisin, or any other wrong whereby he that has the right to a freehold is kept out of possession. 'Deforciant' was formerly the technical name of the defendant in the fictitious proceeding called a Fine. In Scotland, the term deforcement is most commonly used to denote forcible obstruction of the officers of the law this is one of the cases in which the Court of Session has a criminal jurisdiction.

Deformities are variations in the form of the body as a whole, or in one or more of its parts, constituting a departure from the normal conditions of structure, and usually implying a corresponding divergence from natural and healthy functions. They may be divided into three groups, with reference to their origin-the hereditary, the congenital, and the acquired. The first group is characterised by a marked tendency to recurrence in the line of direct descent from generation to generation, as in those cases where the presence of extra fingers or toes has become characteristic of many members of one family (for a full record of an interesting case in point, see Carpenter's Human Physiology). Such hereditary tendencies to modification of form along certain lines of descent constitute local examples of the Natural Law of Variation,' which plays an important part in the Darwinian theory of the origin of species. According to this theory, modifications which are of value in the exigencies of the struggle for existence will become perpetuated, and supersede earlier and less favourable conditions of conformation; while modifications that do not possess such value, after repetition through one or two generations, disappear again, and these, since they are useless as well as aberrant conditions, are properly included within the group of hereditary deformities. In the second group, that of congenital deformities, occur those much more frequent abnormalities that result from disturbing influences acting on the otherwise normal embryo previous to its birth. These anomalies occur chiefly as deformities by defective development, and deformities by perverted development. Arrested development may be general, affecting the whole body, when a dwarf is produced; local, affecting individual organs or parts, producing a great variety of obvious local deformities, in disproportion or malformation of special regions of the body. If the local arrest of development is absolute, the defect caused by it is so great as to constitute a Monstrosity (q.v.), where whole organs may be absent, as the brain (anencephalia), the skull (acrania), the lower jaw (agnathia), all the limbs (amelus), or one or more of them (monobrachius, monopus). Perverted development is seen in cases where parts normally separate become fused together, as in the siren-monster,' in which both lower limbs are welded into one tapering extremity. The causes producing these congenital monstrosities and the lesser and more common deformities of the same class are very varied and often very obscure. Modern writers have, however, made them a subject of special study under the name Teratology (teras, monster," logos, 'science'), and have devised experimental conditions which illustrate the subject. Thus, in the case of the embryo chick, Panum found that deformities could be produced by varying the temperature of the hatching apparatus, and varnishing the egg shells; while Dareste discovered that a like result occurs if the eggs be placed vertically instead

or

of lying on their sides; and Gerlach, by varnishing the whole surface of the egg with the exception of a Y-shaped streak on one side, succeeded in producing a double-bodied chicken.

In the human subject the cause of the deformity may depend on purely mechanical conditions, as when the navel-string of the embryo becomes twisted round a limb and causes its gradual separation and destruction (so-called 'intra-uterine amputation'). In many cases, however, the cause is much more recondite, and appears to depend upon a variety of circumstances affecting the maternal organisation. In an increasing proportion of cases which are carefully investigated, it appears that maternal impressions, the result of shock or unpleasant experiences, may have a considerable influence in producing deformities in the offspring. This has for long been a popular theory, and it is one that recent scientific observation is tending to confirm, but only in a comparatively limited proportion of cases; and it must be admitted that the majority of cases cannot be explained on any theory of causation as yet suggested. The chief varieties of malformation, coming under the heading of congenital deformities, are the following: (1) As regards the number of parts. In the Siren, two lower extremities are fused into one mass, but dissection shows that all the constituent bones of the limbs may be present, though much distorted, in the combined structure. In the Cyclops, the eyes are similarly fused into one irregular structure occupying the centre of the face. (2) As regards the size of parts. This may involve the whole body, as in dwarfs, of whom there have been some remarkable peripatetic specimens: the Corsican fairy was only 2 feet 7 inches high; Mademoiselle Crachami, the smallest lady who ever lived, died at ten years of age, only 20 inches in height. This kind of deformity is not necessarily hereditary; the father of Borowlaski, who was only 39 inches when thirty years old, had six children alternately short and tall; and dwarf women have brought forth infants as long, when extended, as their mothers. One limb only may be diminutive. Of course, deformities the opposite of these exist, such as giants, or instances of premature or excessive local growth. O'Byrne, the Irish giant, measured 8 feet 4 inches when he died at the age of twenty-two. Such individuals are generally subject to premature decay. One finger or one toe often grows to such abnormal dimensions as to necessitate its removal (local hypertrophy). (3) As regards the shape and continuity of parts. Distortion may occur from partial paralysis or irregular muscular action at an early stage of development, giving rise to Club-foot (q.v.), club-hand, &c.; or natural fissures or apertures which should close in the course of development may remain open, as in harelip, cleft palate, and spina bifida.

Acquired deformities arise in various ways as the result of injury or disease at any period after birth. Among injuries, burns, scalds, fractures, and dislocations are the most fertile causes of permanent deformity; and among diseases, rickets, and other diseases of bone, leprosy, and rheumatic affections are common causes. Another group of these affections, known as 'trade' deformities, are directly traceable to the special work done by the person suffering from them.

Defregger, FRANZ, painter, was born at Stronach, near Lienz, 30th April 1835. He studied under Piloty at Munich, and himself became a professor in the Munich Academy, the late King Louis conferring on him the Bavarian order of the Crown in 1883. The subjects of his pictures are almost all drawn from the everyday life or the history of his native Tyrol.

a

Degeneration, a biological term used to describe those not unfrequent cases where an entire organism falls below the structural level of its young stages, or where an organ in the same way loses its fullness of function, and becomes more or less atrophied, abortive, and simplified. Thus many parasitic worms, crustaceans, &c. are emphatically simpler than their free-swimming larvae, and the sessile adult Ascidian shows only traces of the vertebrate characters. which are plain enough in the active young. Thus, too, a crustacean which starts with a well-developed eye, may exhibit the gradual loss of this on assuming a dark habitat. The term is best confined to cases where а level of structure exhibited during early life is more or less lost in the adult. Degeneration must be distinguished (a) from occasional abortion, (b) from Reversion (q.v.) to an ancestral type, and (c) from the occurrence of rudimentary and undeveloped organs where character possessed by ancestral types remains more or less undeveloped, or shows itself only in embryonic life. Degeneration may be due to the environment, or to cessation of function, or to some more subtle constitutional cause. Absence of food, heat, light, &c. may mean the absence of the necessary stimulus for the growth and maintenance of the organs, or superfluity of food may cause one system to preponderate over others. Nor can it be doubted that cessation of function checks the foodsupply to a given organ, and in other ways helps to bring about its degeneration. But on the other hand, some less obvious cause-the fatigue of early life, a constitutional sluggishness, &c. may share in conditioning degeneration, as in the case of the majority of the Tunicata. Weismann and others, however, would explain degeneration by what they call the non-operation of natural selection. On this view, organs are not only developed but maintained by natural selection, and if it happen that an organ is no longer an advantage in this struggle for existence (e.g. eyes in dark caves), then natural selection no longer maintains that organ, and it disappears in the course of generations. Weismann applies this ultra-Darwinian conception especially to cases which might be called non-development rather than actual degeneration-e.g. to the slightly developed wings of the Apteryx. Most cases of degeneration properly so called appear hardly to require his subtle explanation, but find a sufficient one in the nature of the environment, in the effects of stopped function, and in the constitution of the organism. See Ray Lankester, Degeneration (Nature series, 1880); and Weismann, Ueber den Rückschritt in der Natur (Freiburg, 1887). See also, for instances, ASCIDIANS, CAVE-ANIMALS, CRUSTACEA, INSECTS, PARASITISM; also ENVIRONMENT, EVOLUTION, &c.

De Gérando, JOSEPH MARIE, BARON, author and philanthropist, was born 29th February 1772, at Lyons, France. His family was originally from Italy. In 1797 he went to Paris, but soon fled to Germany, where he entered the army of Massena as a common soldier. While with his regiment, De Gérando wrote a treatise, which was crowned by the Academy, and which was afterwards enlarged and published under the title of Des Signes et de l'Art de Penser (1800). In 1802 appeared his De la Génération des Connaissances Humaines, a precursor of his Histoire de Philosophie (1803), long reputed the best French work on the subject. It procured him, in the following year, admission into the Academy. He was appointed secretary-general to the Ministry of the Interior by Napoleon. But De Gérando is even better known by his philanthropic writings. His excellent work, Le Visiteur du Pauvre (1820), obtained the Montyon prize, as did also his Du Perfectionnement Moral (1824).

DEGREE

De Gérando was elevated to the peerage in 1837, and died 12th November 1842, vice-president of the Council of State.

Deggendorf, a town of Lower Bavaria, on the Danube, which is here crossed by two bridges, 39 miles NW. of Passau by rail, with manufac tures of paper, linen, woollens, stoneware, and matches. Its church of the Holy Sepulchre is often Pop. 6446. visited by more than 30,000 pilgrims annually.

Degraded, in Heraldry, means placed upon steps or degrees.

Degree, the 360th part of the circumference of a circle; see CIRCLE, GRADUATION. A degree of latitude is the length along a Meridian (q.v.), such that the difference of latitude between its north and south ends is one degree-i.e. from the two positions the altitude of the same star is seen to differ by one degree (see LATITUDE). Another definition is that two points on the earth's surface differ in latitude by one degree, when the verticals at these points make angles with the plane of the equator, differing by one degree. Were the earth perfectly spherical in shape, this distance along a meridian would be exactly equal to of the whole meridian, and would be the same at all parts of the earth's surface. But owing to its oblately spheroidal shape it increases from the equator, where the curvature is greater, to the poles, where it is less curved. From geodetical measurements made, it is found that at the equator the length of a degree of latitude is 362746-4 feet while at the poles it is 366479.8 feet. The differences between the length of the degree of latitude in different latitudes, thus ascertained by actual measurement, is one of the proofs that the figure of the earth is not that of a sphere but that of an oblate ellipsoid.

;

A degree of longitude is the length between two meridians that make an angle of one degree at the poles, measured by the arc of a circle parallel to the equator passing between them. It is clear that this space is greatest at the equator, and vanishes at the poles; and it can be shown that it varies with the cosine of the angle of latitude. The annexed table shows the lengths of a degree of longitude for places at every degree of latitude from 0° to 90°. It is computed on the supposition that the earth is a sphere.

DEGREES

Degrees, UNIVERSITY. In its original signification a degree was simply a certificate that the person who held it was qualified to take part in the public teaching of a university. In the fully developed medieval university there were the four faculties of arts, law, medicine, and theology; and in each of these faculties there were special degrees of its own. These degrees were the bacalaureate, the licentiate, and the doctorate, though, strictly speaking, the first was not a degree, since it did not confer the right of public teaching. For the attainment of each degree certain subjects were prescribed for examination, as also a fixed term of study in connection with some university. Both the subjects and the periods of study varied with the progress of learning; but the different universities always sought to preserve a common standard. In Paris, at the close of the 15th century, the terms of study requisite to qualify for teaching in the different faculties were the following: in arts, four years; in law, seven; in medicine, eight; and in theology, fourteen. In modern times a degree in arts is simply a certificate of a certain measure of acquaintance with the subject to which it refers; but in the case of the higher faculties, that is, of law, medicine, and theology, the degree also implies a license to exercise the functions of the professions that depend on these faculties. It was formerly an indispensable condition to obtain a degree that the knowledge it represented should have been acquired at one or other of the legally constituted universities; but of late years certain universities, such as that of London, have been founded, which grant degrees to persons who pass examinations on prescribed subjects without the necessity of university attendance. A still further departure from the original import of the term is seen in what are known as honorary degrees.' Such degrees are conferred by universities on persons who have distinguished themselves in spheres of life which have no direct connection with the studies for which they exist. Thus, eminent soldiers, artists, and even merchants, have received the degree of Doctor of Laws. Not a few scholastic bodies are even understood to grant degrees on purchase, or on other such easy conditions that the original significance of the degree is completely lost. In the middle ages the right to confer degrees was granted by the pope, who was the recognised head of all the universities; and at the present day he claims the privilege of directly conferring degrees on whom he pleases. In Protestant countries the right can be granted only by the state. By an act of the reign of Henry VIII., the Archbishop of Canterbury received the right of conferring degrees; but these, known as 'Lambeth degrees,' never carried with them the same privileges as those of Oxford and Cambridge. In the medieval universities, music made part of the curriculum of the faculty of arts, and doctors and bachelors of music are still created by some universities. The German doctorate in philosophy corresponds in some respects to the M.A. degree elsewhere. The degrees of doctor and bachelor of science are of comparatively recent institution. For the usual abbreviations for degrees, see ABBREVIATIONS. See also UNIVERSITY, DOCTOR; and for the Chinese system of degrees, see CHINA, p. 190.-For degrees of relationship,

see CONSANGUINITY.

De Gubernatis. See GUBERNATIS.

Dehiscence (Lat., 'gaping'), a technical term applied to the mode of opening of certain ripe fruits, those which do not open being termed indehiscent. See FRUIT.

Dehra, the capital of the Dehra Dún district in the North-western Provinces of India, is pleasantly

situated in a mountain-valley, 2300 feet above sealevel, and 100 miles NE. of Meerut. Pop. (1881) 18,959.

The

and sister of Meleager. She became the wife of Deianeira, daughter of Eneus and Ethea, Hercules, but unwittingly caused his death by sending him the mantle of the centaur Nessus, which was said to have the property of preserving love, but was really steeped in fatal poison. poison entering his frame, the hero suffered such in Mount Eta, and cast himself into the flames, agony that he ordered a funeral pyre to be erected whereupon Deianeira hanged herself from grief. formula taken from several apostolical expressions Dei Gratia (Lat., by the grace of God') is a

first formally used by the bishops at the Council in the New Testament. It is believed to have been of Ephesus, 431 A.D. Afterwards, it came to be appended by archbishops, bishops, abbots, monks, and even chaplains, to their titles, in letters, and other documents, as a humble expression of dependence on the Most High. After the middle of the 13th century, the higher clergy wrote Dei et Apostolica sedis gratiâ, by the favour of God and the apostolic see. In the British Islands, this style was generally dropped about the time of the Refor mation, but it was occasionally given to the Archbishops of Canterbury and York, even after the beginning of the 17th century. Many temporal princes, earls, and barons made use of the formula Dei Gratiâ; William II. and Edward III. of England employed it; and before the 15th century, no idea of independence or of divine right seems to have been attached to it. But in 1442 King Charles VII. of France forbade its use by the Comte d'Armagnac, and in 1449 obliged the Duke of Burgundy to declare that he used it without prejudice to the rights of the French crown. These instances show that it had now begun to be regarded as belonging exclusively to sovereigns who owed no allegiance to any other earthly potentate or power. In this way, what was originally a pious expression of humility came to be looked upon as an assertion of the doctrine of the divine right' of kings. Deinotherium. See DINOTHERIUM. Deipnosophists. See ATHENÆUS.

from the Tees to the Humber, and westwards to Deira, an ancient Anglian kingdom, extending the borders of Cumbria. With its northern neighbour, Bernicia, it was afterwards merged in the kingdom of Northumbria, but later both were earldoms under the West Saxon kings.

Deir el-kamar ('convent of the moon'), a town of Syria, formerly the capital of the Druses, 13 miles SSE. of Beyrout. It is situated on the edge of a deep and picturesque glen of Mount Lebanon, on the opposite side of which stands the palace Bteddîn, the summer residence of the Christian governor of Lebanon. Pop. 8000, mostly Maronites.

Deism properly means belief in a God, as opposed to atheism; but the term used to ex-press this sense is Theism (q.v.). On the other hand, Deism is generally understood to imply the denial of a revelation; and a Deist is one who holds the existence and providence of God, but grounds his belief on reason and evidence, rejecting the testimony of a revelation. The name is often used vaguely by way of reproach.

The term Deists, or Freethinkers, is usually employed to designate a series of writers who appeared in England in the 17th and 18th centuries, and sought to establish Natural Religion upon the basis of reason and free inquiry, in opposition to all positive religions, and without reference to supernatural revelation. They were critical, if not hostile, in their attitude towards Scripture, and