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BARKER—BARLAAM AND JOSAPHAT

passing nitrogen over heated barium amalgam. It is decomposed by water with evolution of hydrogen, and on heating in a current of carbonic oxide forms barium cyanide (L. Maquenne). Barium amide, Ba(NH2)2, is obtained from potassammonium and barium bromide.

Barium nitrate, Ba(NO3)2, is prepared by dissolving either the carbonate or sulphide in dilute nitric acid, or by mixing hot saturated solutions of barium chloride and sodium nitrate. It crystallizes in octahedra, having a specific gravity of 3.2, and melts at 597° C. (T. Carnelley). It is decomposed by heat, and is largely used in pyrotechny for the preparation of green fire. Barium carbonate, BaCO3, occurs rather widely distributed as witherite (q.v.), and may be prepared by the addition of barium chloride to a hot solution of ammonium carbonate, when it is precipitated as a dense white powder of specific gravity 4.3; almost insoluble in water.

Barium and its salts can be readily detected by the yellowish-green colour they give when moistened with hydrochloric acid and heated in the Bunsenflame, or by observation of their spectra, when two characteristic green lines are seen. In solution, barium salts may be detected by the immediate precipitate they give on the addition of calcium sulphate (this serves to distinguish barium salts from calcium salts), and by the yellow precipitate of barium chromate formed on the addition of potassium chromate. Barium is estimated quantitatively by conversion into the sulphate. The atomic weight of the element has been determined by C. Marignac by the conversion of barium chloride into barium sulphate, and also by a determination of the amount of silver required to precipitate exactly a known weight of the chloride; the mean value obtained being 136.84; T. W. Richards (Zeit. anorg. Chem., 1893, 6, p. 89), by determining the equivalent of barium chloride and bromide to silver, obtained the value 137.44. For the relation of barium to radium, see Radioactivity.


Barker, Edmund Henry (1788–1839), English classical scholar, was born at Hollym in Yorkshire. He entered Trinity College, Cambridge, as a scholar in 1807, but left the university without a degree, being prevented by religious scruples from taking the oath then required. He had previously obtained (in 1809) the Browne medal for Greek and Latin epigrams. After acting as amanuensis to the famous Samuel Parr, the vicar of Hatton in Warwickshire, he married and settled down at Thetford in Norfolk, where he lived for about twenty-five years. He was in the habit of adding the initials O.T.N. (of Thetford, Norfolk) to the title-page of his published works. In later life he became involved in a law-suit in connexion with a will, and thus exhausted his means. In 1837–1838 he was a prisoner for debt in the king's bench and in the Fleet. He died in London on the 21st of March 1839. Barker was a prolific writer on classical and other subjects. In addition to contributing to the Classical Journal, he edited portions of several classical authors for the use of schools. He was one of the first commentators to write notes in English instead of Latin. In a volume of letters he disputed the claims of Sir Philip Francis to the authorship of the Letters of Junius; his Parriana (1828) is a vast and ill-digested compilation of literary anecdotes and criticisms. He also saw through the press the English edition of Lemprière's Classical Dictionary (revised by Anthon) and of Webster's English Dictionary. It is as a lexicographer, however, that Barker is chiefly known. While at Hatton, he conceived the design of a new edition of Stephanus's Thesaurus Graecae Linguae. The work was undertaken by A. J. Valpy, and, although not expressly stated, it was understood that Barker was the responsible editor. When a few parts had appeared, it was severely criticized in the Quarterly Review (xxii., 1820) by Blomfield; the result was the curtailment of the original plan of the work and the omission of Barker's name in connexion with it. It was completed in twelve volumes (1816–1828). The strictures of the Quarterly were answered by Barker in his Aristarchus Anti-Blomfieldianus, which, although unconvincing, was in turn answered by Bishop Monk. He also published notes on the Etymologicum Gudianum, and collaborated with Professor Dunbar of Edinburgh in a Greek and English Lexicon (1831). The editio princeps (1820) of the treatise attributed to Arcadius, Περὶ τόνων, was published by him from a Paris MS. Continental scholars entertained a more favourable opinion of him than those of his own country. He expressed contempt for the minute verbal criticism of the Porsonian school, in which he was himself deficient.

An account of his life will be found in the Gentleman's Magazine for May 1839; see also Notes and Queries (6th series, xii. p. 443), where a full list of his works is given.

Barker's Mill, a mechanical contrivance invented by a Dr Barker about the end of the 17th century. It consisted of a hollow vertical cylinder, provided with a number of horizontal arms fitted with lateral apertures; the contrivance is mounted so as to rotate about the vertical axis. By allowing water to enter the vertical tube, a rotation, due to the discharge through the lateral orifices, is set up.

Barking, a market-town in the Romford parliamentary division of Essex, England, on the river Roding near its junction with the Thames, 8 m. E. of Fenchurch Street station and Liverpool Street station, London, by the London, Tilbury & Southend and Great Eastern railways. Pop. of urban district of Barking town (1891) 14,301; (1901) 21,547. The church of St Margaret is Norman with perpendicular additions, and contains many monuments of interest. Barking was celebrated for its nunnery, one of the oldest and richest in England, founded about 670 by Erkenwald, bishop of London, and restored in 970 by King Edgar, about a hundred years after its destruction by the Danes. The abbess was a baroness ex officio, and the revenue at the dissolution of the monasteries was £1084. There remains a perpendicular turreted gateway. There is also an ancient market-house, used as a town-hall. Victoria Gardens form a public pleasure-ground, and there are recreation grounds. The Gaslight and Coke Company's works at Beckton are in the parish, and also extensive rubber works. At the mouth of the Roding (Barking Creek) are great sewage works, receiving the Northern Outfall sewer from London. There are also chemical works, and some shipping trade, principally in timber and fish. Barking is a suffragan bishopric in the diocese of St Albans.

Barkly East, a town of Cape province, South Africa, capital of a district of the same name, and 80 m. by rail E.S.E. of Aliwal North. The town lies north of the Drakensberg on the Kraai tributary of the Orange river at an elevation of 5831 ft. The district has an area of 1564 sq. m. and a population (1904) of 8490, of whom 50% are whites. The chief occupation followed is sheep-farming, the pasturage being excellent. Like Barkly West, the town and district are named after Sir Henry Barkly, governor of Cape Colony, 1870–1877.

Barkly West, a town of Cape province, South Africa, 21 m. N.W. of Kimberley, capital of a district and of an electoral division of the same name in Griqualand West. It is built on the right bank of the Vaal, here spanned by a bridge. Pop. (1904) 1037. Originally called Klipdrift, the town was the first founded by the diggers after the discovery in 1867 of diamonds along the valley of the Vaal, and it had for some years a large floating population. On the discovery of the “dry diggings” at Kimberley, the majority of the diggers removed thither. Barkly West remains, however, the centre of the alluvial diamonds industry. The diamonds of this district are noted for their purity and lustre, and are generally associated with other crystals—garnets, agates, quartz and chalcedonies.

Barkly West electoral division includes the whole of Griqualand West save the Kimberley division. It is divided into the fiscal districts of Barkly West, Hay and Herbert, with a total pop. (1904) of 48,388, of whom 12,170 are whites (see Griqualand).

Barlaam and Josaphat, one of the most popular and widely disseminated of medieval religious romances, which owes its importance and interest to the fact that it is a Christianized version of the story of Gautama Siddharta, the Buddha, with which it agrees not only in broad outline but in essential details.

The Christian story first appears in Greek among the works of John (q.v.) of Damascus, who flourished in the early part of the 8th century, and who, before he adopted the monastic life, had