THE

NEW · GRESHAM

ENCYCLOPEDIA

VOLUME · IV · PART · 1

The GRESHAM · PUBLISHING
COMPANY · Limited

66 CHANDOS STREET · STRAND
LONDON W.C.2.
1922

LIST OF PLATES

VOLUME IV PART 1

DEPOSITION to EBERSWALDE

PLATES

CONTRIBUTORS TO VOLUME IV

Adolphe Abrahams, O.B.E., B.A., M.D., late Major, R.A.M.C.

George E. Allan, D.Sc., Lecturer in Electricity, University of Glasgow.

C. O. Bannister, F.I.C., Assoc. R.S.N., Professor of Metallurgy, University of Liverpool.

F. F. P. Bisacre, O.B.E., M.A., B.Sc., A.M.Inst.C.E.

R. N. Rudmose Brown, D.Sc.

A. Y. Catto, O.B.E., Lieutenant, R.N.

Grenville A. J. Cole, F.R.S., Professor of Geology, Royal College of Science, Ireland.

W. G. Constable, M.A., Fellow of St. John's College, Cambridge.

Arthur O. Cooke, Author of A Book of Dovecotes.

J. R. Ainsworth Davis, M.A., F.C.P., former Principal of The Royal Agricultural College, Cirencester.

John Dougall, M.A., D.Sc., F.R.S.E., Gold Medallist of the Royal Society of Edinburgh.

Montagu Drummond, M.A., Director of Research, Scottish Station for Research in Plant Breeding.

S. L. Etherton, B.Sc.

Rev. William Fulton, D.D., B.Sc., Professor of Systematic Theology, University of Aberdeen.

R. N. Haygarth, B.A., B.Sc., Queens' College, Cambridge.

W. A. Hislop, M.B., late Captain, R.A.M.C.

D. J. Mackellor, B.Sc., Lecturer in Electrical Engineering, Royal Technical College, Glasgow.

Donald A. Mackenzie, Folklorist; Author of Egyptian Myth and Legend, &c.

Magnus Maclean, M.A., D.Sc., M.Inst.E.E., M.Inst.C.E., Editor of Modern Electrical Engineering, &c.

F. A. Mumby, Editor of The Great World War.

D. G. Ogilvy, LL.B.

R. F. Patterson, M.A., formerly Foundation Scholar of St. John's College, Cambridge, and Charles Oldham (University) Shakespeare Scholar.

Angelo S. Rappoport, Ph.D., B. ès L.

James Ritchie, M.A., M.D., Professor of Bacteriology, University of Edinburgh.

John J. Ross, M.A., F.R.A.S.

G. Elliot Smith, M.A., M.D., F.R.S., Professor of Anatomy, University of London.

C. S. Stocks, D.S.O., Major, Indian Army; Instructor in Military Organization, Royal Military College, Sandhurst.

M. M. J. Sutherland, D.Sc., F.I.C.

Alan C. Thomson, D.S.O., A.M.Inst.C.E., late Lieutenant-Colonel, R.E.

G. E. Toulmin, B.A., King's College, Cambridge.

Thomas Woodhouse, Head of the Weaving and Designing Department, Dundee Technical College and School of Art.

KEY TO PRONUNCIATION

The method of marking pronunciations here employed is either (1) by marking the syllable on which the accent falls, or (2) by a simple system of transliteration, to which the following is the Key:—

VOWELS

ā, as in fate, or in bare.

ä, as in alms, Fr. âme, Ger. Bahn = á of Indian names.

a˙, the same sound short or medium, as in Fr. bal, Ger. Mann.

a, as in fat.

a¨, as in fall.

a, obscure, as in rural, similar to u in but, ė in her: common in Indian names.

ē, as in me = i in machine.

e, as in met.

ė, as in her.

ī, as in pine, or as ei in Ger. mein.

i, as in pin, also used for the short sound corresponding to ē, as in French and Italian words.

eu, a long sound as in Fr. jeûne = Ger. long ö, as in Söhne, Göthe (Goethe).

eu, corresponding sound short or medium, as in Fr. peu = Ger. ö short.

ō, as in note, moan.

o, as in not, soft—that is, short or medium.

ö, as in move, two.

ū as in tube.

u, as in tub: similar to ė and also to a.

u¨, as in bull.

ü, as in Sc. abune = Fr. û as in dû, Ger. ü long as in grün, Bühne.

u˙, the corresponding short or medium sound, as in Fr. but, Ger. Müller.

oi, as in oil.

ou, as in pound; or as au in Ger. Haus.

CONSONANTS

Of the consonants, b, d, f, h, j, k, l, m, n, ng, p, sh, t, v, z, always have their common English sounds, when used to transliterate foreign words. The letter c is not used by itself in re-writing for pronunciation, s or k being used instead. The only consonantal symbols, therefore, that require explanation are the following:—

ch is always as in rich.

d, nearly as th in this = Sp. d in Madrid, &c.

g is always hard, as in go.

h represents the guttural in Scotch loch, Ger. nach, also other similar gutturals.

n˙, Fr. nasal n as in bon.

r represents both English r, and r in foreign words, which is generally much more strongly trilled.

s, always as in so.

th, as th in thin.

th, as th in this.

w always consonantal, as in we.

x = ks, which are used instead.

y always consonantal, as in yea (Fr. ligne would be re-written lēny).

zh, as s in pleasure = Fr. j.

THE NEW
GRESHAM ENCYCLOPEDIA

VOLUME IV

Deposition of a Clergyman, the degradation of a clergyman from office, divesting him (in churches which do not, like the Church of Rome, hold the indelible nature of orders) of all clerical character.

Dépôt (dā'po or dep'ō), a French word in general use as a term for a place where goods are received and stored; hence, in military matters, a magazine where arms and ammunition are kept. The term is now usually applied to a military station situated in the centre of the recruiting district of a regiment, where recruits for this regiment are received and where they undergo preliminary training before joining their unit. In America it is the common term for a railway station.

Deprivation, the removing of a clergyman from his benefice on account of heresy or misconduct. It entails, of course, loss of all emoluments, but not the loss of clerical character.

De Profundis, in the liturgy of the Roman Catholic Church, one of the seven penitential psalms, the 130th of the Psalms of David, which in the Vulgate begins with these words, signifying 'Out of the depths'. It is sung when the bodies of the dead are committed to the grave.

Deptford (det'ford), a parliamentary and municipal borough, England, in the counties of Kent and Surrey, on the right bank of the Thames, now forming part of London. It has some manufactures of pottery, chemicals, and soap. The old naval dockyard was shut up in 1869, but the royal victualling yard is still the largest establishment of its kind. Deptford sends one member to Parliament. Pop. 109,496.

Deputies, Chamber of, the lower of the two legislative chambers in France and in Italy, elected by popular suffrage, and corresponding in some respects to the House of Commons in Britain.

De Quincey, Thomas, English author, was the son of a Manchester merchant, and born at Greenhay, near Manchester, on 15th Aug., 1785, died at Edinburgh, 8th Dec., 1859. In 1793 his father died, leaving the family a fortune of £30,000. After attending some time the Bath and Manchester grammar schools, where he showed precocious ability, especially in classical studies, he importuned his guardian to send him to Oxford University, and on being refused he ran away from school, ultimately arriving in London in an absolutely destitute condition. His sufferings at this time he has described in his Confessions of an English Opium Eater. At length, in 1803, he matriculated at Oxford, and it was in the second year of his course here that he began to take opium in order to alleviate severe neuralgic pains. On leaving college he settled at Grasmere, Westmoreland, in the vicinity of Wordsworth and Southey, and devoted himself to literary work. Here or in London he remained till 1828, reading voraciously, and writing for the London Magazine, Knight's Quarterly Magazine, and Blackwood's Magazine. From 1828 to 1840 he lived in Edinburgh, then removed with his family to Lasswade, which continued to be his head-quarters. His writings, nearly all contributions to magazines, are distinguished by power of expression, subtle thought, and an encyclopædic abundance of curious information. His work belongs to that class of literature which he himself called "the literature of power", as distinguished from "the literature of knowledge". He was eccentric in his habits, incapable of managing money matters, but amiable and polite.—Bibliography: A. H. Japp, Thomas De Quincey: his Life and Writings; H. S. Salt, De Quincey; J. Hogg, De Quincey and His Friends; Sir L. Stephen, Hours in a Library; Arvede Barine, Poètes et Névrosés.

Dera Ghazi Khan, a district and town in the Punjab, Hindustan. The former, which is in Derajat division, has an area of 5606 sq. miles, and a population of 445,000. The town has a population of 18,466, half Hindus and half Mohammedans. It has extensive manufactures of silk, cotton, and coarse cutlery.

Dera Ismail Khan, a town in Hindustan, in the North-West Frontier Province, several miles to the west of the Indus, which is here crossed by boat-bridges, or boats, connecting the town with the Indus Valley railway. Dera Ismail Khan is a staple place for cotton goods, has a cantonment, and carries on a trade with Afghanistan. It is well laid out, has several schools and a large bazaar. Pop. 35,131.

Derajat (-jät´), a commissionership of Hindustan, in the west of the Punjab, occupying part of the valley of the Indus. It is well watered and fertile, and contains numerous towns and villages. Pop. 1,800,000, mostly Mohammedans.

Derbend´, or Derbent´, a fortified town in Daghestan, Transcaucasia, on the west shore of the Caspian, an ancient place formerly belonging to Persia. The manufactures consist of woollen stuffs, copper- and iron-ware, and rose-water; and there is some trade in saffron, largely grown in the vicinity. Pop. 32,718.

Derby, Edward Geoffrey Smith Stanley, fourteenth Earl of, an English statesman, born at Knowsley Park, Lancashire, 29th March, 1799, died there, 23rd Oct., 1869. In 1820 he was returned to the House of Commons as member for Stockbridge. At first inclining to the Whig party, he joined Canning's ministry in 1827, and in 1830 became Chief Secretary for Ireland in Lord Grey's Government, greatly distinguishing himself by his speeches in favour of the Reform Bill in 1831-2. The opposition led by O'Connell in the House of Commons was powerful and violent, but Stanley, while supporting a Bill for the reform of the Irish Church and the reduction of ecclesiastical taxation, was successful in totally defeating the agitation for the repeal of the Union. He warmly advocated the abolition of slavery, and passed the Act for this purpose in 1833; but in the following year a difference of opinion with his party as to the diversion of the surplus revenue of the Irish Church led him to join the Tories. In 1841 he became Colonial Secretary under Sir Robert Peel, but resigned on Peel's motion for repeal of the corn laws. In 1851 and 1858 he formed ministries which held office only for a short period; and again in 1860, when his administration signalized itself by the reform of the government in India, the conduct of the Abyssinian War, and the passing of a Bill for electoral reform (1867). Early in 1868, owing to failing health, he resigned office, recommending Disraeli as his successor. Lord Derby joined to great ability as a statesman, and brilliant oratorical powers, a high degree of scholarly culture and literary ability. Among other works he published a successful translation of Homer's Iliad in 1864.—Cf. T. E. Kebbel, English Statesmen Since the Peace of 1815: Derby.

Derby, Edward George Villiers Stanley, seventeenth Earl of, British politician, born in April, 1865. He served for some years in the Grenadier Guards, and entered the House of Commons in 1892. In 1895 he became a Lord of the Treasury, in 1900 Financial Secretary to the War Office, and in 1903 Postmaster-General. He succeeded to the earldom in 1908. Lord Derby became quite famous as the originator of the Derby Scheme, when he was Director-General of Recruiting in 1915. Under-Secretary for War in 1916, he succeeded Lloyd George as Secretary when the latter became Premier. In 1918 he was appointed British Ambassador in Paris, but resigned his position in Sept., 1920, and left Paris in Nov., greatly to the regret of the French people, to whom he had proved a staunch friend.

Derby, a municipal, parliamentary, and county borough in England, capital of Derbyshire, on the Derwent, here crossed by a graceful bridge of three arches, 115 miles N.N.W. of London. It is pleasantly situated in a wide and fertile valley open to the south, and is well and regularly built in the modern quarter. It has some fine public buildings, amongst which are the churches of All Saints, St. Alkmund, and St. Werburgh, the county hall, school of arts, and infirmary. There is also a very handsome free library and museum. The manufactures include silk, cotton, hosiery, lace, articles in Derbyshire spar, iron castings, and porcelain; and the principal engineering works of the Midland Railway are here. Derby is one of the oldest towns in the kingdom, and is supposed to owe its origin to a Roman station, Derventio. Under the Danes it took the name of Deoraby. Richardson, the novelist, and Herbert Spencer were natives. It returns two members to Parliament. Pop. 123,930 (1919).—The county of Derby, in the centre of the kingdom, is about 55 miles long and from 15 to 30 miles broad; area, 650,369 acres, five-sixths being arable or in permanent pasture. It exhibits much varied and romantic scenery, the southern and eastern parts having a fertile soil, while the north-western portion is bleak, with a rocky and irregular surface. Here is the loftiest range of the English Midlands, the mountains of the Peak. The Peak itself is 2000 feet high. The principal rivers are the Derwent, the Trent, the Wye, the Erwash, the Dove, and the Rother. Oats and turnips are important crops, and dairy-husbandry is carried on to a large extent. Coal is abundant in various parts of the county, iron-ore is also plentiful, and lead, gypsum, zinc, fluor-spar, and other minerals are obtained. The manufactures are very considerable, especially of silk, cotton, and lace, machinery, and agricultural implements. The county is divided into

eight parliamentary divisions, each with one member. Pop. 683,423.—Cf. J. C. Cox, Derbyshire.

Derby-day, the great annual London holiday, on which is run the horse-race for the stakes instituted by Lord Derby in 1780. It always takes place on a Wednesday, being the second day of the grand race-meeting which falls in the week after Trinity Sunday. The race is run on Epsom Downs, an extensive Surrey course 15 miles from London. The course is 1½ miles, and the time usually about 2 minutes, 42 seconds. The entry money of each subscriber is fifty guineas, and the stakes are run for by three-year-old colts and fillies entered when yearlings. In the first year of the Derby there were only thirty-six entries, but they are now very numerous, and the value of the winner's prize is at least £5000. The race is the most popular of British sporting events. The Ascot races are patronized by royalty; the world of fashion is to be found at Goodwood; but Derby-day draws to Epsom a vast crowd of every class. During the European War the race was suspended, but a substitute Derby was run at Newmarket from 1915 to 1918. In 1919 the Derby was again run at Epsom, and was won by Lord Glanely's Grand Parade. In 1920 it was won by Loder's Spion Kop, and in 1921 by Joel's Humorist.

Derby Scheme, a scheme produced by Lord Derby in 1915 with a view to making a final effort on behalf of voluntary recruiting. The National Register (q.v.), taken in August, 1915, of all persons between the ages of fifteen and sixty-five, had shown that over five million men of military age had not 'joined up'. As the number of recruits each week fell short of the number required by Lord Kitchener, Lord Derby, appointed Director of Recruiting, produced a scheme in which men were divided into 46 groups. Groups 1 to 23 were for single men, and groups 24 to 46 for married men. Thus a married man of eighteen was in group 24, whilst a single man of forty-one was in group 23. The scheme ensured that single men would be called up first, whilst men who had 'attested' could appeal to a tribunal and claim temporary or permanent exemption. Two and a half millions offered themselves in consequence of the Derby Scheme, and two millions were accepted.

Dereham (dēr´am), East, a town in England, nearly in the centre of the county of Norfolk, with manufactures of agricultural implements, iron-foundries, and a brisk trade. The poet Cowper was buried in the church there, and George Borrow was born there in 1803. Pop. 5524.

Der´elict, a vessel or anything relinquished or abandoned at sea, but most commonly applied to a ship abandoned by the crew and left floating about.

Derg, Lough: (1) a lake, Ireland, county of Donegal, about 3 miles long by 2½ miles broad at the broadest part, and studded with islets, one of which, called Station Island, is a great resort of Roman Catholic pilgrims; (2) an expansion of the River Shannon between County Tipperary and Counties Clare and Galway, about 24 miles long and averaging 2 miles in breadth.

Derham, William, English philosopher and divine, born in 1657, died 1735. He was long rector of Upminster in Essex. In 1696 he published his Artificial Clockmaker. His best-known works are entitled Physico-Theology, Astro-Theology, and Christo-Theology.

Derma, or Dermis, is the true skin lying under the epidermis (cuticle), which is known in contrast as the scarf-skin.

Dermes´tes, a genus of beetles, one species of which (D. lardarius) is known by the name of bacon-beetle, and is often found in ill-kept ham or pork shops.

Dermot Mac Murragh, the last Irish King of Leinster, attained the throne in 1140. Having carried off the wife of O'Ruare, Prince of Leitrim, he was attacked by the latter, and after a contest of some years driven out of Ireland (1167). He then did homage to the English king, and with the help of Richard, Earl of Pembroke, recovered his kingdom, but died in the same year (1170), and was succeeded by Pembroke, who had married his daughter.

Dernburg, Bernhard, German financier and administrator, born in Darmstadt in 1865. His father was an editor of the Berliner Tageblatt. At the age of nineteen he came to New York to study banking methods, stayed there for several years, and on his return to Germany became director of a financial company. In 1906 he succeeded Prince von Hohenlohe Langenburg as Colonial Secretary. During his administration the condition of German colonies, and especially of German East Africa, was greatly improved. From 1914 to 1915 he was a zealous organizer of German propaganda in the United States, but was subsequently compelled to leave the country.

Déroulède, Paul, French poet, politician, and agitator, born in Paris in 1846, died there in 1914. Called to the Bar in 1870, he served in the Franco-Prussian War, and afterwards carried on an active and passionate agitation for a war of revenge against Germany. He founded the Ligue des Patriotes, which was suppressed by the Government in 1889, was an ardent supporter of General Boulanger, and one of the leaders of the reactionary forces during the Dreyfus case. He sat in the Chamber of Deputies from 1893 to 1895 and from 1898 to 1899. In 1900 he plotted against the Republic, and sought to bring about a nationalist coup d'état with a view to overthrowing the parliamentary constitution. Found

guilty, he was sentenced to ten years' exile, but was allowed to return in 1905, under the law of amnesty. His works include: Chants de Soldat (1872); Nouveaux Chants de Soldat (1875); Chants du paysan (1894); Poésies Militaires (1896); La Moäbite, a religious drama (1880), forbidden by the Censor; and L'Helman, a patriotic play (1877).

Derrick, a simple kind of crane, chiefly used on board ship, consisting of a stout pole swung from a mast, and carrying hoisting-tackle at its upper end. The name is derived from that of a celebrated hangman.

Derringer, a small pocket pistol with a short barrel and a large calibre (usually .41), very effective at short range. It is named after its inventor, a gun-smith in the United States of America, and would seem to have been first used in about 1850. It is a single-shot weapon, and so has largely been superseded by revolvers and automatic pistols.

Der´vish, or Dervise (Pers., 'seeking doors' or beggar, and equivalent to the Ar. fakir), a Mohammedan devotee, distinguished by austerity of life and the observance of strict forms. There are many different orders of dervishes, the underlying idea of most of them being the revival and increase of the Moslem faith. Some live in monasteries, others lead an itinerant life, others devote themselves to menial or arduous occupations. They are respected by the common people, and the mendicants among them carry a wooden bowl into which the pious cast alms. One of their forms of devotion is dancing or whirling about, another is shouting or howling, uttering the name Allah, accompanied by violent motions of the body, till they work themselves into a frenzy and sometimes fall down foaming at the mouth. They are credited with miraculous powers, and are consulted for the interpretation of dreams and the cure of diseases. See Mohammedanism.—Bibliography: E. W. Lane, Modern Egyptians; J. P. Brown, The Dervishes, or Oriental Spiritualism; S. M. Zwemer, Arabia, the Cradle of Islam.

Der´went, the name of four rivers in England, in Derbyshire, Yorkshire, Durham, and Cumberland respectively, the last draining Derwentwater Lake. Also a river in Tasmania.

Derwentwater, James Radcliffe, third and last Earl of, one of the leaders in the rebellion of 1715, born in London 28th June, 1689. The standard of revolt having been raised in Scotland, Lord Derwentwater commenced the movement in England on 6th Oct., 1715, but was forced, along with the other Jacobite nobles, to surrender at discretion on 13th of Nov. He was executed on Tower Hill 24th Feb., 1716, his estates being confiscated, and in 1735 granted to Greenwich Hospital.

Der´wentwater, or Keswick Lake, a beautiful lake in Cumberland, England, in the vale of Keswick. It is about 3 miles in length and 1½ miles in breadth, and stretches from Skiddaw on the north to the hills of Borrowdale. Near the south-east corner is the celebrated cascade of Lodore. Its waters are carried to the sea by the Derwent.

Derzhavin (der-zhä´vin), Gabriel Romanovitsh, a Russian lyric poet, born in 1743, died in 1816. He entered the army as a private soldier, distinguished himself highly, and was eventually transferred to the Civil Service, in which he obtained the highest offices. In 1803 he retired from public life and devoted himself entirely to poetry. One of his most beautiful poems is Oda Bog, or The Address to the Deity.

Desaguadero (des-a˙-gwa˙-dā´rō), a river of Bolivia, in a valley of the same name, issuing from Lake Titicaca, and carrying its waters into Lake Aullagas. Also a river in the Argentine Confederation flowing into Lake Bevedero Grande, and separating the provinces of San Juan and Mendoza. Desaguadero signifies in Spanish 'a channel of outlet'.

Desaix de Veygoux (dė-sā dė vā-gö), Louis Charles Antoine, a distinguished French general, born in 1768 at St. Hilaire d'Ayat, in Auvergne, died 1800. He was of noble family, and entered the army as a sub-lieutenant. He distinguished himself greatly in 1794 under Pichegru, and two years later with the army of the Rhine under Moreau. In 1797 he accompanied Bonaparte to Egypt, and was very successful in reducing Upper Egypt. After the Treaty of El Arish he followed Bonaparte to Italy, took command of the corps of reserve, and, arriving on the field of Marengo at a critical moment, decided the victory by a brilliant charge, 14th June, 1800. He himself fell, mortally wounded by a musket bullet.

Desault (dė-sö), Pierre Joseph, one of the most celebrated surgeons of France, was born in 1744, and died in 1795. After some experience in the military hospital at Béfort, he went to Paris in 1764, studied under Petit, and two years afterwards became a lecturer on his own account. His reputation soon increased, and he became principal surgeon in the Hospital de la Charité, and in 1788 was put at the head of the great Hôtel Dieu in Paris. Here he founded a surgical school, in which many of the most eminent surgeons of Europe were educated. A digest of his surgical works was published by Bichat in 1798 (Œuvres chirurgicales de Desault).

Des´cant, in music, an addition of a part or parts to a subject or melody, a branch of musical composition which preceded the more modern counterpoint and harmony, coming into existence at the end of the eleventh or beginning of the twelfth century.

Descartes (dā-kärt), René, a great French philosopher and mathematician, with whom the modern or new philosophy is often considered as commencing. He was born 31st March, 1596, at La Haye, in Touraine, died 11th Feb., 1650. Educated at the Jesuit College of La Flèche, where he showed great talent, he entered the military profession and served in Holland and in Bavaria. In 1621 he left the army, and after a variety of travels finally settled in Holland, and devoted himself to philosophical inquiries. Descartes, seeing the errors and inconsistencies in which other philosophers had involved themselves, determined to build up a system anew for himself, divesting himself first of all of the beliefs he had acquired by education or otherwise, and resolving to accept as true only what could stand the test of reason. Proceeding in this way, he found (Meditationes de Prima Philosophia) that there was one thing that he could not doubt or divest himself of the belief of, and that was the existence of himself as a thinking being, and this ultimate certainty he expressed in the celebrated phrase "Cogito, ergo sum" (I think, therefore I am). Here, then, he believed he had found the test of truth. Starting from this point Descartes found the same kind of certainty in such propositions as these: that the thinking being or soul differs from the body (whose existence consists in space and extension) by its simplicity and immateriality and by the freedom that pertains to it; that every perception of the soul is not distinct; that it is so far an imperfect finite being; that this imperfection of its own leads it to the idea of an absolutely perfect being; and from this last idea he deduces all further knowledge of truth. Descartes has been rightly called the father of modern philosophy, for in him the modern spirit came into existence. In an age of unrest and ferment his work was that of a great systematizer. He also contributed greatly to the advancement of mathematics and physics, the method of co-ordinates, which has revolutionized geometry, and is of fundamental importance in modern mathematical physics, being due to him. His system of the universe attracted great attention in his time. One of his fundamental doctrines was that the universe is full of matter, there being no such thing as empty space. On this basis he developed the hypothesis of celestial vortices, immense currents of ethereal matter, by which he accounted for the motion of the planets (Principia Philosophiæ, 1644). His works effected a great revolution in the principles and methods of philosophy. In 1647 the French court granted him a pension of 3000 livres, and two years later, on the invitation of Christina of Sweden, he went to Stockholm, where he died.—Bibliography: Sir J. P. Mahaffy, Descartes; A. Fouillée, Descartes; E. Boutroux, L'Imagination et les mathématiques selon Descartes; N. Smith, Studies in Cartesian Philosophy; E. S. Haldane, Descartes: his Life and Times.

Descent´, in law, is the transmission of the right and title to lands to the heir, on the decease of the proprietor, by the mere operation of law. The rule determining to whom an estate belongs, on the decease of the proprietor, is that of consanguinity, or relationship by blood, though with some exceptions, as in the case of the portion, or the use of a portion, of a man's property given by the laws of Britain to his widow. The rules of descent, designating what relations shall inherit, and their respective shares, will be determined by the genius and policy of the Government and institutions. Hence the practice of entailments in the feudal system. And wherever the Government is founded in family privileges, or very intimately connected with them, as is the case in all Governments where the hereditarily aristocratical part of the community has a great preponderance, the sustaining of families will very probably be a characteristic feature in the code of laws. Thus, in Britain, all the lands of the father, unless otherwise directed by will, go to the eldest son. (In England, however, this privilege may shortly be abolished, or the succession to real estate assimilated to the succession to personal estate.) In the United States of America this distinction in favour of the eldest son has been abolished, and the laws there are founded upon the principle of equal distribution both of real and personal estate among heirs of the nearest surviving degree. Kindred in blood are divided into three general classes, viz. 1, descendants; 2, ancestors; 3, collateral relatives, that is, those who have descended from the same common ancestor. The civil law computes the degrees by counting the generations up to the common ancestor, as father, grandfather, great-grandfather; or mother, grandmother, great-grandmother; and from him or her down to the collateral relative, as brother, cousin, &c., making the degree of relationship the sum of these two series of generations. Every person has two sets of ancestors, the paternal and maternal, and therefore two sets of collateral relatives. There is also a distinction of collateral kindred, into those of the whole blood and those of the half blood.—Cf. Pollock and Maitland, History of English Law.

Deschanel, Paul Eugène Louis, French statesman and tenth President of the French Republic, born at Brussels on 13th Feb., 1856, where his father was in exile for opposition to Napoleon III. Educated at the Collège Sainte Barbe and the Lycée Condorcet, Paris, he was private secretary first to De Marcère, the Home Secretary, in 1876, and then to the Premier,

Jules Simon, in 1877. Sub-prefect at Dreux, Brest, and Meaux, he was elected to the Chamber of Deputies in Oct., 1885, for Nogent le Rotrou. In the Chamber of Deputies he soon displayed his power of eloquence, and eventually became the leader of the Progressive Republicans and exponent of the separation of Church and State. His authority, which he owed not only to his eloquence but also to his great tact and correct and dignified conduct during debates, gradually increased in the Chamber of Deputies, and even his political enemies admired his courage and his superiority of intellect. He was consequently elected Vice-President of the Chamber in 1896 and in 1897, and succeeded Henri Brisson as President of the Chamber in 1898, retaining his office till 1902, when M. Léon Bourgeois became President of the Chamber. Re-elected President of the Chamber in 1912, and withdrawing his candidature to the presidency of the Republic in favour of Poincaré in 1913, Deschanel retained his post until 1920, when he was elected President of the Republic by 734 votes. In the meantime, however, his health had given way, and on 23rd May, 1920, he fell out of a moving train, an accident resulting in a prolonged illness. A prompt recovery was at first expected, but this hope soon proved vain. Unable to attend to the duties of his office, he resigned on 16th Sept., and was succeeded by Alexandre Millerand. He was elected to the Académie Française on 18th May, 1899, and his works include: La Question du Tonkin (1883), La Politique Française en Océanie (1884), Orateurs et Hommes d'État (1888), Figures des Femmes (1889), Figures Littéraires (1889), La Question Sociale (1898), Quatre ans de Présidence (1902), Politique Intérieure et étrangère (1906), Paroles Françaises (1911), La France Victorieuse (1919), and Gambetta (1920).

Deseada (de-se-ä´da˙), or Désirade, one of the Leeward Islands, belonging to the French, in the Caribbean Sea, about 10 miles long and hardly 5 miles broad. The soil is in some places black and good, in others sandy and unproductive. Pop. about 1500.

Deser´tion. In the military sense this implies the act of an officer or soldier who, either with the intention of not returning at all or of returning when by reason of his absence it has become impossible for him to perform a given duty, absents himself from His Majesty's service. The essence of the offence is intention, and this must be proved to the satisfaction of the court martial by which the offender is tried. The distance travelled is no criterion, and a man arrested while leaving the barracks in disguise may be tried for attempted desertion. In this connection it should be noted that an attempt to desert, or an attempt to procure another person to desert, is also an offence, and is punishable under Section 12 of the Army Act equally with the completed act. As far back as the middle of the fifteenth century the crime of desertion by a soldier was made a felony triable by the ordinary law of the land, and with certain interludes death remained the maximum penalty for desertion for some 200 years. The present existing Army Act recognizes two degrees of desertion, i.e. that committed on active service or when under orders for active service, and that committed under other circumstances. Under the former heading the maximum punishment is death; under the latter, imprisonment or penal servitude, according to the number of times the offence has been committed. A soldier convicted of desertion forfeits the whole of his service prior to conviction.

Desertion, in law, the term applied to the act by which a man abandons his wife or a wife her husband. Such desertion without due cause is, in England, ground for a judicial separation. Property a wife may have acquired since desertion is protected against her husband, and he may be forced to provide for her maintenance. By Scottish law, where either the husband or wife has deserted and remained separate without due cause for four years, divorce may be obtained.

Deshoulières (dā-söl-yār), Antoinette du Ligier de Lagarde, a French woman of much literary reputation in the seventeenth century, born 1638, died 1694. She was the centre of attraction in the best circles of the period, and was elected a member of several learned societies. She wrote in the Mercure Galant under the name of Amaryllis, and Boileau has described her in his tenth Satire. Among her works are odes, eclogues, idyls, and a tragedy (Genseric).

Desiccation, a process of dispelling moisture by the use of air, heat, or chemical agents such as chloride of calcium, quicklime, oil of vitriol, and fused carbonate of potash.—Desiccation cracks, in geology, are the fissures caused in clayey beds by the sun's heat, and seen in various rock strata.

Design, thought, arrangement, or grouping, imagination or invention in works of art. A design is a composition or invention, pictorial, architectural, or decorative. It may be simply an imperfect sketch, as a record of a first thought; or it may be a fully matured work, as a cartoon in preparation for fresco painting, or a drawing to illustrate a book.

Desmidia´ceæ, or Desmidie´æ, a family of microscopic, fresh-water Green Algæ, group Conjugatæ. They are green gelatinous plants composed of variously formed cells having a bilateral symmetry, which are either free, or in linear series, or collected into bundles or into

star-like groups, and embedded in a common gelatinous coat. Desmidiaceæ differ from Diatomaceæ in their green colour and absence of silica.

Desmo´dium, a large genus of leguminous plants, sub-ord. Papilionaceæ, natives of tropical and sub-tropical countries. D. gyrans is the telegraph plant, so called from the curious movements performed by the two small lateral leaflets of each leaf, which, at high temperatures, wave up and down like the arms of a semaphore.

Des Moines (dė moin), a city of the United States, capital of the state of Iowa and of Polk County, on the Des Moines River, about 350 miles west of Chicago. Among its chief buildings are the new State house, the State arsenal, university, and opera-houses. There are coal-mines in the vicinity, and the manufactures and other industries are varied and rapidly increasing. Pop. 104,052 (1917).

Des Moines, the largest river in the state of Iowa, rises in the S.W. of Minnesota, and flows in a south-easterly direction till it falls into the Mississippi about 4 miles below Keokuk, after a course of 300 miles.

Desmoncus, a genus of tropical American climbing palms, scrambling by means of stout hooks which are modified leaflets.

Desmoulins (dā-mö-lan), Benoît Camille, born in 1760, was conspicuous during the first period of the French Revolution. He was amongst the most notable of the pamphleteers and orators who urged the multitude forward in the path of revolution. He, along with others, prepared the plan for the taking of the Bastille (July, 1789), was one of the founders of the club of Cordeliers, and the promoter of the assembly in the Champ de Mars. In 1789 he began his career as a journalist by the issue of a weekly publication (Les Révolutions de France et de Brabant). In 1793 he gave his vote for the death of the king. Having become closely connected with Danton and the party of opposition to Robespierre, and inveighing against the reign of blood and terror, he was arrested on the order of the latter on 30th March, 1794, tried on the 2nd April, and executed on the 5th. He met his fate in an agony of despair.—Cf. F. A. Aulard, Les Orateurs de la Législative et de la Convention.

Desna, a river in the Ukraine, which rises in the government of, and about 50 miles east of the town of Smolensk, flows through the governments of Orel and Tshernigov till it joins the Dnieper near Kiev. It is 500 miles in length and navigable nearly throughout.

De Soto, Hernando, a Spanish explorer and discoverer of the Mississippi, born about 1496, died in 1542. He accompanied expeditions to the New World under Davila and Pizarro, and played a distinguished part in the conquest of Peru. In 1536 he led an expedition to Florida, whence after many difficulties he penetrated to the Mississippi, where he was attacked with fever and died.—The name De Soto has been given to a county in the N.W. of Mississippi, and to several places in the United States.

Des´pot (Gr. despotēs), originally a master, a lord; at a later period it became an honorary title which the Greek emperors gave to their sons and sons-in-law when governors of provinces. At present despot means an absolute ruler, and in a narrower sense a tyrannous one.

Dessalines (dā-sa˙-lēn), Jean Jacques, Emperor of Hayti, born in Africa about 1760. He was a slave in 1791, when the insurrection of the blacks occurred in that island, but was set free along with the other slaves in St. Domingo in 1794. His talents for war, his courage, and unscrupulous conduct raised him to command in the insurrections of the coloured people, and after the deportation of Toussaint-L'Ouverture, and the subsequent evacuation of the island by the French, Dessalines was appointed Governor-General for life with absolute power; and the year following (1804) was declared Emperor with the title of Jacques I. But his rule was savage and oppressive, and both the troops and the people, sick of his atrocities, entered into a conspiracy against him, and on 17th Oct., 1806, he was slain by one of his soldiers.

Dessau (des´ou), a town in Germany, capital of the former Duchy of Anhalt, in a beautiful valley on the left bank of the Mulde, mostly well built, with fine squares and many handsome buildings. The manufactures consist of woollens, woollen yarn, carpets, machinery, and tobacco. The former ducal palace has a picture-gallery and interesting relics and antiquities. Pop. 56,606.

De Stendhal. See Beyle, Marie-Henri.

Dester´ro, now Florianopolis, a seaport of Brazil, capital of the state of Santa-Catharina. The harbour, next to Rio de Janeiro, is the best in Brazil. Pop. 9000.

Destructors, Refuse, the apparatus or plant used in the cremation of house and factory refuse. Formerly refuse from large towns and populous areas was either disposed of for manurial purposes or spread over waste land, where its presence speedily became a nuisance. The consequent danger to the public health, coupled with the increasing difficulty and cost of its disposal, led to attempts being made to deal with it by more sanitary methods. The first attempts to cremate it in a closed furnace on a large scale, made in London in 1870, were not successful, primarily owing to the unscientific design of the furnace. In 1877, however, there was built in Manchester the forerunner of the

modern destructor, to the designs of the late Mr. Alfred Fryer. This consisted of two simple cells, the primary feature of the design being 'the charging of the refuse into the back of the furnace, and drawing out the resulting clinker from the front'. With certain modifications, this design is in general use at the present time. The basic principles underlying their scientific design may be summed up in the following points: (a) Charging at regular intervals, the refuse being dumped into a hopper, and fed into the back of the furnace as a charge, means being taken to prevent undue escape of gases. The moisture having evaporated, the material may then be raked forward onto the fire-bars, where combustion takes place. (b) To avoid nuisance, the resulting gases must be inodorous, which requires a temperature of about 2000°F. This is obtained by passing the products of combustion over the hottest portion of the fire, prior to their passage into the main flue. (c) Removal of the fine dust and particles in suspension in the flue gases by means of spiral chambers at the base of chimney. (d) Provision of forced draught. A well-designed plant should show little, if any, suspended matter in the gases on emission from the chimney. Formerly no use was made of the heat generated, but modern installations now invariably have steam-raising plant incorporated in the design. This power is commonly used to generate electricity. Some portion may be utilized in crushing and screening the clinker, which is frequently used in making slab-paving, or ground fine and used as a substitute for sand in mortar. The following data may be found of service: (a) 60 per cent of the average refuse is combustible. (b) The calorific value may be taken as being one-seventh that of good steam-coal. (c) 100 electrical units may be obtained from each ton of refuse consumed. (d) With forced draught, as much as 100 lb. of refuse has been burnt per square foot of grate area per hour. (e) 250 tons of refuse per annum per 1000 of population may be estimated for.—Bibliography: W. H. Maxwell, Removal and Disposal of Town Refuse; Kempe, Engineer's Year Book.

Destutt de Tracy, Antoine Louis Claude, French philosophical writer, born in 1754 of a family of Scottish extraction, died in 1836. As a philosopher he belonged to the Sensationalist school, and considered all our knowledge to be derived originally from sensation. He has been called the logician and metaphysician of the school of Condillac. Among his chief works are: Idéologie (1801), Logique (1805), and Traité de la Volonté (1815).

Deter´minant, a mathematical expression which appears in the solution of a system of equations of the first degree.

The solution of the equations

a₁x + b₁y = c₁,

a₂x + b₂y = c₂,

is given by

x(a₁b₂ - a₂b₁) = c₁b₂ - c₂b₁,

y(a₁b₂ - a₂b₁) = a₁c₂ - a₂c₁.

Here x and y have the same coefficient a₁b₂ - a₂b₁. This is called a determinant of the second order, and is written

|a₁, b₁|

|a₂, b₂|.

We may now write

Similarly with three equations,

a₁x + b₁y + c₁z = d₁,

a₂x + b₂y + c₂z = d₂,

a₃x + b₃y + c₃z = d₃,

we find

x{a₁(b₂c₃ - b₃c₂) + a₂(b₃c₁ - b₁c₃) + a₃(b₁c₂ - b₂c₁)}

= d₁(b₂c₃ - b₃c₂) + d₂(b₃c₁ - b₁c₃) + d₃(b₁c₂ - b₂c₁)

The coefficient of x, and the right-hand member, are here determinants of the third order, and the result is written

When the coefficient of x is expanded fully, it consists of six terms, half of them positive and half negative, each term being the product of three letters, one from each row and one from each column. Thus in every term, such as the leading term a₁b₂c₃, the three letters a, b, c, and the three suffixes 1, 2, 3, all occur once and once only. With regard to the signs, we note that if the letters a, b, c are always kept in this order, an interchange of two suffixes changes the sign. Thus, e.g. we may start from + a₁b₂c₃, interchange the suffixes 2 and 3, and thus find - a₁b₃c₂. Again, if in the latter term - a₁b₃c₂ we interchange the suffixes 1 and 3, we find + a₃b₁c₂. It is easy to verify that after any number of interchanges of this kind a particular term will always come up with the same sign.

Thus the interchange of two rows (and similarly of two columns) changes the sign of the determinant. It follows that if two rows (or two columns) are identical, the determinant is zero. It is now easy to define functions of n² letters, arranged in a square array of n rows

and n columns, with similar properties to those observed above in the case of determinants of the third order. Determinants are very extensively used in higher algebra, co-ordinate geometry, and other branches of mathematics. See also Elimination.—Bibliography: C. Smith, Algebra; T. Muir, Theory of Determinants.

Determinants, in biology, the name applied by Weismann to hypothetical particles contained in the nuclei of germ-cells, which determine the existence and nature of the various parts of the body of the embryo. The theory of determinants is part of an elaborate attempt to explain the facts of heredity on a mechanical basis. Although it may serve as a working hypothesis, it is regarded with disfavour by many experts, and may be regarded as an elaboration of the 'provisional theory of pangenesis' advanced by Darwin.

Deter´minism, a term employed by recent writers, especially since J. Stuart Mill, to denote a philosophical theory which holds that the will is not free, but is invincibly determined either—according to the older form of the theory—by a motive furnished by Providence, or—according to the modern form—by the aggregation of inherited qualities and tendencies. Biological determinism maintains that each of our voluntary acts finds its sufficient and complete cause in the physiological conditions of the organism. Psychological determinism ascribes efficiency to the psychical antecedents. Opposed to determinism is the doctrine of indeterminism or indifferentism. See Free-will.

Det´inue, in law, the form of action whereby a plaintiff seeks to recover a chattel personal unlawfully detained.

Det´mold, a town, Germany, capital of Lippe-Detmold, on the left bank of the Werra, 50 miles south-west of Hanover, with a new and an old palace (or castle), good public library, and museum. In the vicinity a colossal statue has been erected to the Hermann or Arminius who overthrew the Roman general Varus and his legions in a battle which was fought near this place. The Senner race of horses is bred near Detmold. Pop. 14,295.

Det´onating Powders, certain chemical compounds which, on being exposed to heat or suddenly struck, explode with a loud report, owing to one or more of the constituent parts suddenly assuming the gaseous state. The chloride and iodide of nitrogen are very powerful detonating substances. Mercuric fulminate or fulminating mercury (C₂HgN₂O₂) explodes violently when forcibly struck or when heated to 180°F. It is used for making percussion caps, and in detonators for exploding guncotton and nitroglycerin preparations. Silver fulminate (C₂Ag₂N₂O₂) explodes even more violently.

Detonating Tube, a species of eudiometer, being a stout glass tube used in chemical analysis for detonating gaseous bodies. It is generally graduated into centesimal parts, and perforated by two opposed wires for the purpose of passing an electric spark through the gases which are introduced into it, and which are confined within it over mercury and water.

Detroit (de-troit´; Fr. détroit, a strait or channel), a flourishing port and city of the United States, the largest town in Michigan, situated on the Detroit River, connecting Lakes Erie and St. Clair. The site rises gradually from the river, and the city is generally well built. Among the chief edifices are the city hall, the house of correction, post office, and opera-house. Detroit has increased very rapidly, a fact which is due to its admirable position for trade, and to its connections with a region into which a constant tide of emigration is flowing. Among the industrial establishments are saw-mills, flour-mills, building-yards for ships and boats, foundries, tanneries, blast-furnaces, pork-packing establishments, tobacco and cigar manufactories, and locomotive works. The harbour is one of the finest in the United States, and has a depth of water sufficient for the largest vessels. Detroit owes its origin to the French, who visited the site in 1648 and erected the Fort Pontchartrain in 1701. Pop. 688,028 (1919).

Detroit River, or Strait of St. Clair, a river or strait of North America which runs from Lake St. Clair to Lake Erie. It is 28 miles long, and of sufficient depth for the navigation of large vessels. It is about ¾ mile wide opposite Detroit and enlarges as it descends.

Dettingen (det´ing-en), the name of several places in Germany, amongst which is a village of Bavaria, on the right bank of the Main, famous for the victory gained by the English and Austrians under George II of England over the French in 1743.

Deuca´lion, in Greek mythology, the son of Prometheus and father of Hellen, ancestor of the Hellenes. According to tradition he saved himself and his wife, Pyrrha, from a deluge which Zeus had sent upon the earth, by building a ship which rested upon Mount Parnassus. To repair the loss of mankind they were directed by an oracle to throw stones behind them; the stones thrown by Deucalion became men, those thrown by Pyrrha women.

Deus ex Machinâ (mak´i-na; Lat., 'a god out of the machine'), a phrase used to designate the resorting to supernatural causes to explain phenomena that one is not able to account for by natural means. The phrase is taken from the practice on the classical stage of introducing a god from above by means of some mechanical contrivance in order to effect a speedy dénouement of the plot.

Deuteronomy (Gr. deuteronomion, the second law), the name of the fifth book of the Pentateuch (q.v.). Until the seventeenth century it was believed to have been written by Moses, but now it is generally held to be a compilation, the bulk of it having been written in the reign of Manasseh, or according to other scholars in the reign of Josiah. At any rate the book was discovered or rediscovered while Josiah was king (2 Kings, xxii). It represents the latest phase in the development of the teaching of Moses. Its chief aim is to combat idolatry, and to concentrate the religious life of the country at Jerusalem. It has a lofty moral tone. Of one passage (vi, 4 and 5) Christ said: "On these two commandments hang all the law and the prophets" (Matt. xxii, 40), and all His answers to the Tempter in the Wilderness are taken from the book of Deuteronomy.

Deutz (doits), a town in Prussia, on the right bank of the River Rhine, opposite the city of Cologne, with which it communicates by a bridge. It is strongly fortified as part of the defences of Cologne, in which it is now incorporated. There are some manufactories of porcelain and glass, also an iron-foundry and machine-works. Pop. 17,060.

Deut´zia, a genus of plants, nat. ord. Saxifragaceæ, containing seven or eight species, all of which are interesting from the beauty of their flowers, some of them favourite garden and greenhouse plants. They are small shrubs indigenous to China and Japan, and Northern India.

De Valera, Eamon, Irish Republican, born at New York in 1883, his father being a Spaniard, and his mother an Irishwoman. Educated at the Royal University of Ireland, he early became known for his revolutionary activities. In 1917 he was elected president of the Gaelic League and was arrested as an agitator. Elected to Parliament in 1918, while he was in prison, he refused to take his seat. He was elected 'President' of the so-called 'Irish Republic' soon afterwards, and in Feb., 1919, escaped from prison and reached New York, where he started an active propaganda and began to raise funds for the Irish cause. He returned to Ireland in 1921.

Dev´enter, an old town in Holland, province of Overijssel, 8 miles north from Zutphen, at the confluence of the Schipbeek and Ijssel. Its industries embrace carpets, cast-iron goods, printed cottons, hosiery, and a kind of cake called Deventer Koek. It has a large export trade in butter. Pop. 32,483 (1918).

Dev´eron, a river of Scotland belonging to Aberdeenshire and Banffshire, 60 miles long. It flows into the Moray Firth at Banff.

Deviation of the Compass, the deflection of a ship's compass needle from the magnetic meridian, caused by adjacent iron. Hard iron is very retentive of a magnetic state, and is specially liable to become magnetized during a hammering process, as in the building of the ship. Soft iron easily receives or loses magnetism, and its magnetic state varies with every shifting of the ship's head. The effect of the former can be counteracted by magnets suitably placed near the compass, that of the latter by spheres of soft iron. The ship is swung, and the compass errors found in the various positions. The effects of the several contributing causes can then be separated, and the nature of the correctors necessary inferred with considerable accuracy. When these have been provided, the small residual errors for different positions of the ship are determined, and a table is constructed from which the navigator may read the slight correction to apply to the indication of his compass in steering any desired course.

Device´, a name common to all figures, ciphers, characters, rebuses, and mottoes which are adopted by a person or a family by way of badge or distinctive emblem, often a representation of some natural body, with a motto or sentence applied in a figurative sense.

Devil (Gr., diabolos, a slanderer or accuser), in theology, the name given to a fallen angel, who is the instigator of evil, and the ruler of darkness. Most of the old religions of the East acknowledge a host of devils. The doctrine of Zoroaster, who adopted an evil principle called Ahriman, opposed to the good principle and served by several orders of inferior spirits, spread the belief in such spirits among the people. The Greek mythology did not distinguish with the same precision between good and bad spirits. With the Mohammedans Eblis, or the devil, was an archangel whom God employed to destroy a pre-Adamite race of jinns, or genii, and who was so filled with pride at his victory that he refused to obey God. The Satan of the New Testament is also a rebel against God. He uses his intellect to entangle men in sin and to obtain power over them. But he is not an independent self-existent principle like the evil principle of Zoroaster, but a creature subject to omnipotent control. The doctrine of Scripture on this subject soon became blended with numerous fictions of human imagination, with the various superstitions of different countries, and the mythology of the pagans. The excited imaginations of hermits in their lonely retreats, sunk as they were in ignorance and unable to account for natural appearances, frequently led them to suppose Satan visibly present; and innumerable stories were told of his appearance, and his attributes—the horns, the tail, the cloven foot,—distinctly described. Theology has always treated the devil from a psychological or ethical

standpoint. From the New Testament we hardly learn more regarding the devil than that he has a distinct personality; that he is a spirit or angel who in some way fell; that he is devoid of truth and of all moral goodness, always warring against the soul of man and leading him towards evil; that he has demons, spirits, or angels under him who work his will, and enter into or 'possess' men; but of his or their origin, original state, or fall, we really learn nothing.—Bibliography: Mayer, Historia Diaboli; Lecanu, Histoire de Satan, sa chute, son culte, ses manifestations, ses œuvres; Carus, History of the Devil.

Devil-fish, the popular name of various fishes, one of them being the angler. Among others the name is given to several large species of ray (especially Ceratoptera Vampyrus which attains the breadth of 20 feet) occasionally captured on the Atlantic and Pacific coasts of America, and much dreaded by divers, whom they are said to devour after enveloping them in their vast wings. During gales of wind or owing to strong currents these immense fish are driven into shoal water, and, being unable to extricate themselves, fall an easy prey to the fishermen, who obtain considerable quantities of oil from their livers. The name is also applied to the larger eight-armed cephalopod molluscs belonging to Octopus and allied genera. A combat with one of these is described in Victor Hugo's Toilers of the Sea.

Devil's Bit, the common name of a British species of scabious (Scabiōsa succīsa), nat. ord. Dipsaceæ. It has heads of blue flowers nearly globular, and a fleshy root, which is, as it were, cut or bitten off abruptly. It flowers from June to October, and is common in meadows and pastures.

Devil's Bridge, a name for several bridges in wild situations; one being in Cardiganshire, spanning a gorge of the Mynach; another in Switzerland, over which the St. Gothard Railway crosses the Reuss.

Devil's Parliament, the name given to a Parliament convened by Henry VI, which met at Coventry in 1459 and unjustly accused the Duke of York of high treason.

Devil's Punch-bowl, a small lake of Ireland, near the Lakes of Killarney, between 2000 and 3000 feet above the sea, supposed to be the crater of an ancient volcano. The name is also given to Highcomb Bottom, a glen in Surrey.

Devil's Wall, in the south of Germany, a structure which was originally a Roman rampart, intended to protect the Roman settlements on the left bank of the Danube and on the right bank of the Rhine against the inroads of the Teutonic and other tribes. Remains of it are found from the Danube, in Bavaria, to Bonn, on the Rhine.

Devil-worship, the worship paid to the devil, an evil spirit, a malignant deity, or the personified evil principle in nature, by many of the primitive tribes of Asia, Africa, and America, under the assumption that the good deity does not trouble himself about the world; or that the powers of evil are as mighty as the powers of good, and have in consequence to be bribed and reconciled. There is a sect called devil-worshippers inhabiting Armenia and the valley of the Tigris, who pay respect to the devil, to Christ, and to Allah or the supreme being, and also worship the sun.

Devise, in law, usually the disposition of real estate by will, but also sometimes applied to any gift by will, whether of real or personal estate.

Devitrification. Glass which has been kept for a considerable time at a temperature just below its fusion-point gradually becomes opaque or crystalline in appearance; this phenomenon is spoken of as devitrification. Poor glass, badly prepared window-glass, and glass which has been subjected to strain tend to devitrify on exposure to air, some of the ingredients separating in a crystalline form.

Devi´zes, a town in England, county of Wilts, giving name to a parliamentary division, finely situated on a commanding eminence, 82 miles west by south of London. The name is derived from the Lat. divisæ (terræ, divided lands), because the ancient castle of Devizes was built at the meeting-place of three different manors. Agricultural engines and implements are made, and malting is carried on. Pop. 6740.

Devon, or Devonshire, a maritime county in the s.w. of England, its northern coast being on the Bristol Channel and its southern on the English Channel; area, 1,671,364 acres, the county being the third largest of England. Its principal rivers are the Torridge and the Taw, flowing north into the Bristol Channel; and the Exe, Axe, Teign, Dart, and Tamar, flowing into the English Channel. From Exeter to the confines of Cornwall extends the wide and barren tract called Dartmoor; but the vale of Exeter, comprising from 120,000 to 130,000 acres, and the south extremity of the county called South Hams, limited by a line drawn from Torbay to Plymouth Sound, are amongst the most fertile districts of England. Tin, lead, iron, copper, manganese, granite, and the clay used by potters and pipe-makers are the chief mineral products. The geological formation of the Old Red Sandstone is so largely developed that the term Devonian has to some extent become its synonym. Agriculture is in a somewhat backward state, owing, probably, to the general preference given to dairy husbandry, for which the extent and richness of its grass-lands make the county most

suitable. Wheat, barley, beans, pease, and potatoes are the principal crops. About three-fourths of the county is under crops or in pasture. There is a large trade in butter, cheese, and live-stock, and the 'clotted' cream and cider of Devonshire are well known as specialities of the county. There are seven parliamentary divisions, each with one member. Pop. 699,703.—Bibliography: Victoria County History, Devonshire; F. J. Snell, Devonshire, Historical, Descriptive, and Biographical.

Devo´nian System, in geology, a name originally given to rocks in Devonshire and Cornwall, intermediate between the Silurian and Carboniferous strata, and consisting of sandstones, calcareous slates and limestones, &c. They are divided into lower, middle, and upper series, the middle most abounding in fossils, including corals, crinoids, brachiopods, and molluscs. Devonian rocks occupy a large area in Central Europe, as well as in the United States, Eastern Canada, and Nova Scotia. The terrestrial and lacustrine equivalents are known as the Old Red Sandstone.

Dev´onport, formerly a county borough and port of England, county of Devon, contiguous to Plymouth. It is the seat of one of the royal dockyards, and an important naval and military station. A bastioned wall and fosse defend the town on the north-east and south sides, while the sea entrance is protected by heavy batteries on Mount Wise. Connected with the dockyards and fortifications are the gun wharf, foundries, machine-works, rope-walks, store-houses, and naval and military barracks. It has no special trade beyond that connected with the dockyards and Government works. Formerly a parliamentary borough, returning two members to Parliament, Devonport now gives its name to a parliamentary division of Plymouth, with which it is amalgamated since Nov., 1914. Pop. 84,370.

Devonshire, Spencer Compton Cavendish, eighth Duke of, long known as Marquess of Hartington, born in 1833, died 1908. He was the eldest surviving son of the seventh Duke of Devonshire, whom he succeeded in the dukedom in 1891. He was educated at Trinity College, Cambridge, where he graduated as M.A. in 1854. He was attached in 1856 to Earl Granville's Russian mission, and in 1857 was elected as a Liberal one of the members for North Lancashire. In 1863 he was for a short time a Lord of the Admiralty, and he then became Under-Secretary for War, being raised to Cabinet rank as War Secretary in 1866. In 1868 he lost his seat for North Lancashire, but became Postmaster-General under Gladstone, and was returned for the Radnor boroughs. In 1871 he was appointed Chief Secretary for Ireland. He went out with the Gladstone ministry in 1874, and on Gladstone's retirement he became the leader of the Liberal party. On the fall of the Conservative Government in 1880 he was elected for North-East Lancashire, and became Secretary for India under Gladstone, being transferred to the War Office in 1882. In the general election of 1885 he was returned for the Rossendale division of Lancashire. He strenuously opposed Gladstone's Home Rule Scheme of 1886, and became the leader of the Liberal Unionists, but long declined to take office in the Cabinet. In 1895, however, he became Lord President of the Council, and from 1900 to 1902 he was President of the newly-instituted Board of Education. In 1903 he withdrew from co-operating with Mr. Balfour as Premier, mainly because he disliked the fiscal changes proposed by Chamberlain. He then accepted the position of head of the Free-Trade Unionists.

Dew is the name given to the minute drops of water which at certain times appear by night upon grass, flowers, foliage, and other surfaces which readily radiate heat. The first attempts at a scientific explanation of dew were made early in the nineteenth century, when Dr. Wells propounded his theory on the subject. According to this, the origin is to be found in the moisture previously contained in a vaporous state in the atmosphere. During the day the earth both absorbs and emits heat, but by night its supply of warmth is cut off, while it continues, under favouring circumstances, to lose heat by radiation into surrounding space. For any given state of the atmosphere, in respect of the amount of aqueous vapour it contains in a specified volume, there is a certain temperature at which it can hold just that amount and no more in suspension. If it be cooled to that temperature, it begins to deposit its moisture in the liquid form, and if the cooling proceeds further, more and more is deposited. This particular temperature is the dew-point appropriate to the given state of humidity of the air. If the dew-point is below 32°F., the vapour will, when the dew-point is reached, pass directly into the solid form and be deposited as hoar-frost. While there is a certain amount of truth in the foregoing theory, it does not contain the whole facts of the case. Dr. John Aitken, of Falkirk, Stirlingshire, established by experiments that in most cases probably the dew found on plants does not come mainly from the atmosphere. To some extent it exudes from the plants themselves. They derive moisture from the soil, and in the process of supplying their tissues it passes to their outer surfaces, whence in the daytime it is evaporated into the air. By night the fall of temperature checks evaporation of this moisture, and when it reaches their surfaces, it may remain there in the form of dew-drops. Also, moisture

is condensed out of the atmosphere upon the cooler plant surfaces, but even this has more often been yielded not long before to the atmosphere through the medium of the plant tissues, so that upon the whole the plants play a much more important part in the process than had been supposed. Dew is most copiously produced when there is a large difference between the day and night temperatures. Hence it is favoured by the absence of clouds, which would throw back much of the heat radiated from the earth. Other favouring circumstances are a still condition of the atmosphere, good radiating surfaces, and an abundant supply of moisture in the soil.

Dewar (dū´a˙r), Sir James, scientist, born at Kincardine-on-Forth, 1842, educated at Dollar Academy, Edinburgh University—where he was assistant to Lord Playfair when professor of chemistry—and Ghent. In 1873 he was elected Jacksonian professor of experimental philosophy at Cambridge, an office which he still holds, and in 1879 a professorial fellow of St. Peter's College. In the latter year he also became Fullerian professor of chemistry at the Royal Institution, London. He is a fellow of the Royal Society, has been awarded several medals and prizes for his scientific researches, including the Rumford medal in 1894 for his investigations into the properties of matter at its lowest temperatures, this branch of science, with which the liquefaction of air and gases is connected, being peculiarly his own. He was the first to reduce hydrogen gas to the liquid and solid form. Together with Sir F. Abel, he was the discoverer of cordite. He is an honorary graduate of several universities, a late president of the Chemical Society and vice-president of the Royal Society, and was president of the British Association in 1902. He has contributed numerous papers to the proceedings of the learned societies of Great Britain, and was knighted in 1904. His collected papers on spectroscopy appeared in 1915.

Dewar Flask, a flask devised by Dewar for the examination of liquefied gases. It consists of an inner vessel surrounded by a vacuum, which much reduces loss or gain of heat by the liquid. The principle now finds practical application in the 'Thermos Flask'.

Dewás, a native state of Central India consisting of two combined states with two chiefs. Total pop. 250,000. Dewás, the chief town, has a pop. of 5200.

Dewberry (Rubus cœsius), a European plant belonging to the ord. of the Rosaceæ, and to the same genus as the bramble, from which it is distinguished by its smaller berries, with fewer grains, and by the bloom, resembling dew, with which they are covered, and from which the plant derives its name. It is common in some parts of England. The Canadian dewberry (R. procumbens) yields a much superior fruit.

De Wet, Christian Rudolf, Boer general, born 1854 in the Orange Free State. His father removing into the Transvaal, he fought as a field-cornet at Majuba. As member of the Volksraad (1889-97) he helped to draw the two Dutch republics together, and in the South African War commanded first in Natal, and then in the west under Cronje, whose rescue at Paardeberg he attempted, but unsuccessfully. After March, 1900, he distinguished himself by his attacks on the British lines of communication, and by his skill in evading capture. He became commander-in-chief of the Free State forces, and was the only undefeated Boer general at the end of the war, after which he, with Louis Botha and Delarey, came to Europe to collect funds for his countrymen. A member of the Legislative Assembly and Minister of Agriculture, Orange Free State, from 1907 to 1914, he joined the rebellion at the outbreak of the European War. Captured at Waterburg on 1st Dec., he was sentenced to a fine of £2000 and six years' imprisonment, but was soon released. He published The Three Years' War in 1902.

Dewey, George, American naval officer, born at Montpellier, Vermont, 26th Dec., 1837, died 16th Jan., 1917. He began active service in the Mediterranean squadron, and in 1862, under Farragut, he was present at the passage of Forts Jackson and St. Philip. Lieutenant-commander in 1865, commander in 1872, he was in command of the Asiatic squadron in 1898, when he destroyed the Spanish fleet at Manila on 1st May. He was made Admiral of the Navy and was thanked by Congress. From 1900 till his death he was President of the General Board of the Navy.

Dewey, John, American philosopher and psychologist, born at Burlington, Vermont, 20th Oct., 1859. Educated at the University of Vermont, he received his Ph.D. degree from Johns Hopkins University. Professor of philosophy at the Universities of Minnesota, Michigan, and Chicago, where he was also director of the School of Education, he became professor of philosophy at Columbia University in 1904. He is one of the two (William James being the other) American leaders of pragmatism, a philosophical conception according to which questions that have no bearing on experience and on life have no significance whatever, and are meaningless. (See Pragmatism.) His works include: Outlines of a Critical Theory of Ethics (1881), Study of Ethics (1894), My Pedagogical Creed (1897), The School and Society (1900), Studies in Logical Theory (1903), How we Think (1909), Interest and Effort in Education (1913), Democracy and Education (1916), Letters from China and Japan (1920).

De Wint, Peter, English landscape painter in water-colours, born 1784, died 1849. He studied in the schools of the Royal Academy, where he occasionally exhibited; but most of his pictures were shown in the exhibitions of the Water-colour Society. English scenery was his favourite subject. He occasionally painted in oil with marked success. Several of his pictures are in the National Gallery and the Victoria and Albert Museum.

De Witt, Jan, Grand-Pensionary of Holland, celebrated as a statesman and for his tragical end, was the son of Jacob de Witt, burgomaster of Dort, and was born in 1625. He became the leader of the political party opposed to the Prince of Orange, and in 1652, two years after the death of William II, was made Grand-Pensionary. In 1665 the war with England was renewed, and conducted by De Witt with great ability till its termination in 1665. In 1672 Louis XIV invaded the Spanish Netherlands and involved Holland in war. De Witt's popularity, already on the decline, suffered still further in the troubles thus occasioned, and he felt it necessary to resign his office of Grand-Pensionary. At this time his brother Cornelius, who had been tried and put to torture for conspiring against the life of the young Prince of Orange, lay in prison. Jan de Witt went to visit him, when a tumult suddenly arose amongst the people, and both brothers were murdered, 20th Aug., 1672. De Witt was a man of high character, simple and modest in all his relations.—Cf. Motley, History of the United Netherlands.

Dew-point, the temperature at which the air is saturated with the water-vapour which it contains. If the temperature of the air falls to the dew-point, dew is deposited. The dew-point is determined by means of an instrument called a hygrometer. When the air is 'dry', the dew-point is low, and evaporation proceeds rapidly, whilst a 'moist' atmosphere is one whose temperature is near the dew-point, and in which evaporation takes place slowly.

Dewsbury, a town, England, in the West Riding of Yorkshire, and 30 miles south-west of the town of York, chiefly engaged in the manufacture of heavy woollen cloths, including blankets, carpets, rugs, flannels, and baizes. In 1862 it was made a municipal borough; in 1867 a parliamentary borough, returning one member. Pop. of municipal borough, 53,351.

A, Dexter chief point.

Dexter, a term meaning on the right-hand side, chiefly used in heraldry. The dexter chief point is a point in the right-hand upper corner of the shield, being in the dexter extremity of the chief.

Dex´trine, or British Gum, (C₆H₁₀O₅)x, a generic name applied to soluble gummy substances intermediate between starch and glucose. They are prepared from starch by the aid of dilute mineral acids or of enzymes, and are usually named according to the colour they give with iodine, e.g. erythro-dextrine, &c. When heated with dilute acids, they are transformed into glucose. They are white, odourless substances, and are good substitutes for gum-arabic. Dextrine is used in calico printing for thickening colours; for the preparation of gums, and for stiffening cloth.

Dextro-compounds, bodies which cause the plane of a ray of polarized light to rotate to the right. Dextrine itself, dextro-glucose, naturally occurring tartaric acid, malic acid, cinchonine, and many other bodies have this property; while others, which have the opposite effect, of causing the plane to rotate to the left, are called lævo-compounds.

Dey, an honorary title formerly bestowed by the Turks on elderly men, and assumed by the rulers (under the Turkish Sultan) of Algiers, Tripoli, and Tunis.

Dhalak (dha˙-la˙k´), an archipelago of the Red Sea, belonging to the Italian territory of Eritrea. It consists of nearly 100 islets, mostly uninhabited, clustering round the Island of Dhalak-el-Kebir, which is about 35 miles long by 30 miles broad. This island possesses a pearl-fishery.

Dhar (dhär), a small native state in Central India, with an area of about 1740 sq. miles. The soil is fertile, and yields wheat, rice, and opium. Pop. 169,474.—The capital is of the same name, is surrounded by a mud wall, and has some striking buildings. Pop. 19,000.

Dhárangaon, a town of Hindustan, in Khandesh district, Bombay. Pop. 15,000.

Dharmsála, a hill station with military cantonments, in Kangra district, Punjab, India. Pop. 6170.

Dharwar, the chief town of Dharwar district, in the Bombay Presidency, Hindustan, a straggling place with some trade. There is a fort well planned and strongly situated, but now falling into ruins, and military cantonments at 2 miles' distance. Pop. 32,000.—The Dharwar district has an area of 4535 sq. miles; pop. 1,051,314.

Dhawala´giri, or Dhaulágiri, one of the highest peaks of the Himalayas, in Nepál; height, 26,828 feet.

Dhole (dōl), the Cingalese name for the wild dog of India (Cyon dukhunensis). It is distinguished from the genus Canis or dog proper by its having one molar fewer in either side of the lower jaw. It is of a fox-red or rufous-fawn colour, in size between a wolf and a jackal, and hunts always in packs.

Dholera (dhō-lā´ra), a town of Hindustan,

Bombay Presidency, on a stream entering the Gulf of Cambay, an important cotton-mart. Pop. 10,190.

Dholka, a town of Hindustan, Bombay Presidency, probably one of the oldest towns in Gujarat. Pop. 16,700.

Dholpur, native state of Central India, Rájputána; area, 1155 sq. miles; pop. 263,188.—The capital is also called Dholpur. Pop. 9750.

Dhow (dou), an Arab sea-going vessel, ranging from a comparatively small size up to 200 tons burden, with one mast and a large triangular (lateen) sail. It is used for merchandise and is often employed in carrying slaves from the east coast of Africa to Arabia.

Dhúliá, a town of Hindustan, Khandesh district, Bombay Presidency. Pop. 22,000.

Diabase, originally an equivalent of diorite; then used for chloritic igneous rocks of the Intermediate series of various grain; and now usually for a type of dolerite in which the felspar is embedded in augite.

Diabe´tes is a disease characterized by great thirst, a voracious appetite, and the passage of large quantities of saccharine urine, while there is usually marked emaciation and debility. As a rule the skin is dry and the patient does not perspire. Skin irritations (pruritus) of an intense type occur frequently and cause much discomfort. Constipation is the rule, but the digestion usually remains good, and enormous quantities of food are taken without causing disturbance.

Acute and chronic forms are recognized, but there is no essential difference, except that in the former the patients are younger, the course more rapid, and the emaciation more marked. Beyond the large quantity, the outstanding feature of the urine is the presence of sugar, varying from 2 per cent in mild cases to 10 per cent in severe cases.

The disease is due to disturbance in the carbohydrate metabolism, with the result that these carbohydrates are not properly assimilated, but passed as sugar in the urine. Much research has been undertaken to find what organ or organs of the body cause this defect in metabolism, and recent work in connection with the pancreas has established a definite relationship between cells in that organ and the disease.

In treatment the main consideration is to reduce the carbohydrates in the dietary, and many diets have been produced for this purpose.

Diabetic patients may take:—liquids: clear soups, lemonade, coffee, tea, cocoa (without sugar), soda-water, and such like waters or milk (in moderation); animal foods: fish of all sorts, fresh meat, poultry, game, eggs, butter, cream-cheese; vegetables: lettuce, tomatoes, spinach, radishes, asparagus, water-cress, cucumbers, chicory, mustard; fruits: lemons, oranges, and in moderation currants, plums, cherries, pears, apples (tart), melons, raspberries, strawberries, nuts: bread: gluten bread, almond or coco-nut biscuits. A substitute for bread is one of the greatest difficulties, as many gluten foods are very unpalatable.

Further, it is important to observe strict personal hygiene and to take moderate exercise, lead a regular, quiet life in an equable climate, and above all to avoid worries of any sort. In acute cases the disease may run a very rapid course, coma frequently supervening a few days before death, but chronic cases may live for ten to twenty years.

Diabetic Sugar. Sugar is present in normal urine in very small amount—so small that it cannot be detected by the ordinary tests. In diabetes the percentage of sugar in the urine may rise, in mild cases, to 1½ to 2 per cent, and in severe cases it may reach to 10 per cent.

Diablerets (dē-a˙b-lė-rā), Les, a mountain group of the Bernese Alps, Switzerland, between the cantons Vaud and Valais. The highest peak has a height of 10,620 feet.

Diachylon (dī-ak´i-lon), a substance prepared by heating together oxide of lead or litharge, olive-oil, and water, until the combination is complete, and replacing the water as it evaporates. It is used for curing ulcers, and is the basis of many plasters.

Di´adem (Gr. diadein, to bind round), an ancient ornament of royalty. It was originally a head-band or fillet made of silk, linen, or wool, worn round the temples and forehead, the ends being tied behind and let fall on the neck, as seen in old representations of the diadem of the Indian Bacchus. In later times it was usually set with pearls and other precious stones. The term is also used as equivalent to crown or coronet.

Diæ´resis, a separation of one syllable into two, also the mark (¨) by which this separation is distinguished, as in aërial.

Diagno´sis, in medicine, the recognition of diseases by their distinctive signs or symptoms; the discovery of the true nature and seat of a disease.

Diag´onal Scale, a scale which consists of a set of parallel lines drawn on a ruler, with lines crossing them at right angles and at equal distances. One of these equal divisions, namely, that at the extremity of the ruler, is subdivided into a number of equal parts, and lines are drawn through the points of division obliquely across the parallels. With the help of the compasses such a scale facilitates the laying down of lines of any required length to the 200th part of an inch. The length 1·67 inches, for example, is given by EF in the figure. Similarly AB = ·91 inch, CD = ·84 inch.

Diag´oras, ancient Greek poet and philosopher, born in Melos, an island of the Cyclades, and flourished about 425 B.C. He spent a great part of his life in Athens. Like his teacher, Democritus, he attacked the prevailing polytheism, and sought to substitute the active powers of nature for the divinities of the Greeks. On this account he had to leave Athens.

Di´agram (Gr. diagraphein, to describe), a figure or geometrical delineation applied to the illustration or solution of geometrical problems, or any illustrative figure in which outlines are chiefly presented, and the details more or less omitted.

Dial, or Sun-dial, an instrument for showing the hour of the day from the shadow thrown by a stile or gnomon upon a graduated surface while the sun is shining. This instrument was known from the earliest times amongst Egyptians, Chaldeans, and Hebrews. From those Eastern nations it came to the Greeks. It was introduced into Rome during the first Punic War. Dials are of various construction, horizontal, inclined, or upright, the principle in every case being to show the sun's distance from the meridian by means of the shadow cast by the stile or gnomon. The stile is made parallel with the earth's axis, and may be considered as coinciding with the axis of the sun's apparent diurnal motion. Consequently, as the sun moves westwards the shadow of the stile moves round opposite to it, in the same direction, falling successively on lines drawn to represent the hours of the day. The dial, of course, gives true solar or apparent time, which, except on four days of the year, is somewhat different from mean time. Dials are now rather articles of curiosity or ornament than of use.—Bibliography: Leybourn, The Art of Dialling; Dawbarn, The Sun-dial.

Di´alect, the language of a part of a country, or a distant colony, deviating either in its grammar, vocabulary, or pronunciation, from the language of that part of the common country whose idiom has been adopted as the literary language, and the medium of intercourse between well-educated people. Although the use of provincial dialects becomes inconvenient after a language has acquired a fixed literary standard, the study of such dialects is always valuable to the philologist for the light they throw on the history of the language. The diffusion of education and of printed books has much relaxed the hold which the provincial dialects of various countries once had on the people, and in general it may be said that the educated classes of any country now speak each of them a uniform language.

Dialec´tics (Gr. dialektice, from dialektos, discourse, dialogue), a philosophic term originally signifying investigation by dialogue. It was first

used by Plato to designate the Socratic method. Afterwards it came to denote the art of inference or argument, and in this sense was synonymous with logic. The term is used in Kant's philosophy to mean the logic of appearance, or that logic which treats of inevitable tendencies towards error and illusion in the very nature of reason.

Di´allage, an altered form of the mineral augite, with a lamellar structure, and a submetallic lustre on its planes of separation. Schillerstein, or schiller spar is a similar product of the allied but rhombic mineral hypersthene. It forms diallage rock, and enters into serpentine rock.

Dialling, the art, of making sundials; also the art and practice of mine-surveying, in which the theodolite and magnetic needle are employed.

Di´alogue, a conversation or discourse between two or more persons. The word is used more particularly for a formal conversation in theatrical performances, and for a written conversation or composition, in which two or more persons carry on a discourse. This form was much in favour amongst the ancient philosophers as a medium for expressing their thoughts on subjects. The Dialogues of Plato are the finest example. Many of the great French and Italian writers have used this form. In the seventeenth century Fontenelle and Fénelon both wrote Dialogues des Morts, a title borrowed from Lucian. Landor's Imaginary Conversations (1821-8) is the best production of this kind in English.

Dial´ysis, the process by means of which a crystalline substance may be separated from a colloidal body. Certain substances are capable of passing through parchment, others are not, e.g. a solution containing sugar and silicic acid may be separated by placing the solution in a parchment-paper tube suspended in water; the silicic acid remains in the parchment tube, and the sugar passes through into the surrounding water. The solution is said to be dialyzed.

Diamagnet´ic, a term applied to substances which, when under the influence of magnetism and freely suspended, take a position at right angles to the lines of magnetic force. From the experiments of Faraday it appears that all matter is subject to the magnetic force as universally as it is to the gravitating force, arranging itself into three divisions, the ferromagnetic, paramagnetic, and diamagnetic. Among the former are iron, nickel, cobalt, magnetic oxide of iron, and Heusler's alloy. The more feebly magnetic bodies are classed as paramagnetics, and those which behave as described above are called diamagnetic substances. Among the latter are bismuth, antimony, cadmium, copper, gold, lead, mercury, silver, tin, zinc, and most solid, liquid, and gaseous substances. A diamagnetic body is one which is not so magnetic as the medium in which it is suspended. The action of bismuth, the strongest diamagnetic substance, is weak when compared with the magnetic action of iron.

Diamanti´na, a town, Brazil, in the diamond-mining district in the state of Minas Geraes, the inhabitants of which are almost all engaged in the gold and diamond trade. Pop. about 14,000.

Diam´eter (Gr. dia, through, and metron, measure), the straight line drawn through the centre of a circle and terminated by the circumference. It thus divides the circle into two equal parts, and is the greatest chord. The length of the diameter is to the length of the circumference of the circle as 1 to 3.14159265..., the latter number being an interminable decimal. The name is also given to any chord of a conic which passes through its centre.

Di´amond, the hardest and one of the most valuable of gems, and the purest form in which the element carbon is found. (See Carbon.) It crystallizes in forms belonging to the regular or cubic system, the most common being the regular octahedron and rhombic dodecahedron (twelve faces). The finest diamonds are colourless, perfectly clear, and pellucid. Such are said to be of the finest water. But diamonds are often blue, pink, green, or yellow, and such are highly prized if of a decided and equal tint throughout. The hardness of the diamond is such that nothing will scratch it, nor can it be cut but by itself. The value of a diamond is much enhanced by cutting facets upon it inclined at certain angles to each other so as to produce the greatest possible play of colour and lustre. What is called the brilliant cut best brings out the beauty of the stone. Its upper or principal face is octagonal, surrounded by many facets. But this form of cutting requires an originally well-shaped stone. For other diamonds the rose cut is used. In this form six triangles are cut on the top so that their apices meet in a point called the summit. Round this are disposed other facets. Stones which are too thin to cut as rose-diamonds are cut as table-diamonds, which have a very slight play of colour. In the cut, fig. 1 is the diamond in its rough state; fig. 2 is the vertical, and fig. 3 the lateral appearance of a brilliant; fig. 4 the

vertical, and fig. 5 the lateral appearance of a rose-cut diamond; in fig. 6 the flat portion a in a cut stone is called the table; the part a b b, which projects from the setting, is the front, the part b b c, sunk in the setting, is the back or culasse, while the line b b is the girdle. The art of cutting and polishing the diamond was unknown in Europe till the fifteenth century, and the stone itself was not nearly so highly valued in the Middle Ages as the ruby. Diamonds are valuable for many purposes. Their powder is the best for the lapidary, and they are used for jewelling watches, and in the cutting of window- and plate-glass. When used as a glazier's tool the diamond must be uncut. Inferior kinds of diamonds are also extensively used by engineers in rock-boring, and by copperplate engravers as etching-points. Diamonds are obtained from deposits of various kinds, mostly alluvial (sands, clays, &c.), being separated by washing. They have been found in India, Borneo, and other parts of the East; sometimes in N. America and Australia; Brazil has produced large numbers; but the chief diamond-field of to-day is in Cape Province, the centre being Kimberley. Diamonds were discovered here in 1867, and since then the output has amounted to over £183,000,000 in value. The diamonds are no longer obtained by mere surface workings, but the excavations have been carried down to a depth of 2000 feet. 'River diggings' are also carried on on the banks of some of the rivers. Some of the S. African diamonds are very large. One of them, the Cullinan diamond, discovered in 1905, is a monster of 3025 carats, of very good colour, being by far the largest diamond known. A celebrated diamond is the Koh-i-noor (Mountain of Light), an Indian stone belonging to the British crown. Its history extends over five or six centuries. It weighed at one time 280 carats, but by cutting has been reduced to about 106 carats. The Orlov diamond, which belonged to the Emperor of Russia, weighed 194 carats; the Pitt diamond, among the French crown jewels, weighs 136½ carats.—Bibliography: A. Jeffries, A Treatise on Diamonds and Pearls; H. Emanuel, Diamonds and Precious Stones; E. W. Streeter, Precious Stones and Gems; idem, The Great Diamonds of the World; G. F. H. Smith, Gem-Stones; P. A. Wagner, The Diamond Fields of Southern Africa.

Diamond-beetle, Entimus imperialis, a handsome South American insect belonging to the family Curculionidæ or weevils. It is spangled with golden-green on a black background.

Diamond Harbour, a port on the left bank of the Hugli River, about 38 miles by the railway from Calcutta, formerly much used as an anchorage for ships waiting for the tide.

Diamond Lore. In Hellenic, Arabian, Chinese, and other literature the diamond is connected with the eagle and snakes. Diamonds, according to ancient belief, lie in deep valleys infested by snakes, or entirely surrounded by straight, high cliffs. Pieces of flesh are thrown down and eagles seize them. The birds are followed to their nests, where the diamonds that adhered to the flesh are found. Mixed with this legend is the older one regarding the 'eagle stone', which assists parturition. It was believed a woman was easily delivered if the 'eagle stone' were placed on her abdomen. The Chinese legend was imported with the diamond from Fu-lin (Syria). Indian diamond lore is mixed with pearl lore. According to the Buddha birth stories, diamonds are found in the sea. The ancients asserted that the diamond could not be injured by iron, fire, or smoke. Before it could be broken it had to be steeped in ram's blood. The alchemists used lead as a substitute for ram's blood. In Chinese lore diamonds are rulers of gold and have their origin in gold. A similar belief prevailed in mediæval Europe, adamantine gold being credited with the same virtues as the diamond. Both gold and the diamond were sacred. The diamond is a mediæval symbol of Christ; in the Far East it is connected with Buddha. The association of the diamond with snakes gave origin to the belief that it was poisonous, the saliva of the snakes clinging to it. Diamond dust is regarded in India as a deadly poison. Like the sacred pearl, the diamond has been credited with nocturnal luminosity. Certain varieties of diamonds when heated, rubbed, or exposed in bright sunshine emit slight rays of light for a short time in darkness. The belief in 'night shining gems', however, had origin in pearl lore, the pearl having been connected with the moon ('the pearl of heaven'). Coral, rhinoceros-horn, fern seed, the mandrake, &c., were likewise connected with the moon-goddess and credited with nocturnal luminosity.

Diamond Necklace, an affair of some note in French history immediately preceding the Revolution. See Marie Antoinette; La Motte; and Rohan, Louis.

Dian´a, in Roman mythology, an ancient Italian goddess, in later times identified with the Greek Artĕmis, with whom she had various attributes in common, being the virgin goddess of the moon, and of the chase, and having as attributes the crescent moon, bow, arrows, and quiver. The name is a feminine form of Janus. She seems to have been originally the patron divinity of the Sabines and Latins. She was worshipped especially by women, as presiding over births, no man being allowed to enter her temple.