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569
MANGAN—MANGANESE

Persian Gulf. There is a small shipbuilding industry. The town has a large Roman Catholic population, with a European bishop, several churches, a convent and a college. It is the headquarters of the Basel Lutheran mission, which possesses one of the most active printing presses in southern India, and has also successfully introduced the industries of weaving and the manufacture of tiles. Two colleges (Government and St Aloysius) are situated here. Mangalore was gallantly defended by Colonel John Campbell of the 42nd regiment from May 6, 1783, to January 30, 1784, with a garrison of 1850 men, of whom 412 were English, against Tippoo Sultan’s whole army.


MANGAN, JAMES CLARENCE (1803–1849), Irish poet, was born in Dublin on the 1st of May 1803. His baptismal name was James, the “Clarence” being his own addition. His father, a grocer, who boasted of the terror with which he inspired his children, had ruined himself by imprudent speculation and extravagant hospitality. The burden of supporting the family fell on James, who entered a scrivener’s office, at the age of fifteen, and drudged as a copying clerk for ten years. He was employed for some time in the library of Trinity College, and in 1833 he found a place in the Irish Ordnance Survey. He suffered a disappointment in love, and continued ill health drove him to the use of opium. He was habitually the victim of hallucinations which at times threatened his reason. For Charles Maturin, the eccentric author of Melmoth, he cherished a deep admiration, the results of which are evident in his prose stories. He belonged to the Comet Club, a group of youthful enthusiasts who carried on war in their paper, the Comet, against the levying of tithes on behalf of the Protestant clergy. Contributions to the Dublin Penny Journal followed; and to the Dublin University Magazine he sent translations from the German poets. The mystical tendency of German poetry had a special appeal for him. He chose poems that were attuned to his own melancholy temperament, and did much that was excellent in this field. He also wrote versions of old Irish poems, though his knowledge of the language, at any rate at the beginning of his career, was but slight. Some of his best-known Irish poems, however, O’Hussey’s Ode to the Maguire, for instance, follow the originals very closely. Besides these were “translations” from Arabic, Turkish and Persian. How much of these languages he knew is uncertain, but he had read widely in Oriental subjects, and some of the poems are exquisite though the original authors whom he cites are frequently mythical. He took a mischievous pleasure in mystifying his readers, and in practising extraordinary metres. For the Nation he wrote from the beginning (1842) of its career, and much of his best work appeared in it. He afterwards contributed to the United Irishman. On the 20th of June 1849 he died at Meath Hospital, Dublin, of cholera. It was alleged at the time that starvation was the real cause. This statement was untrue, but there is no doubt that his wretched poverty made him ill able to withstand disease.

Mangan holds a high place among Irish poets, but his fame was deferred by the inequality and mass of his work, much of which lay buried in inaccessible newspaper files under his many pseudonyms, “Vacuus,” “Terrae Filius,” “Clarence,” &c. Of his genius, morbid though it sometimes is, as in his tragic autobiographical ballad of The Nameless One, there can be no question. He expressed with rare sincerity the tragedy of Irish hopes and aspirations, and he furnished abundant proof of his versatility in his excellent nonsense verses, which are in strange contrast with the general trend of his work.

An autobiography which appeared in the Irish Monthly (1882) does not reproduce the real facts of his career with any fidelity. For some time after his death there was no adequate edition of his works, but German Anthology (1845), and The Poets and Poetry of Munster (1849) had appeared during his lifetime. In 1850 Hercules Ellis included thirty of his ballads in his Romances and Ballads of Ireland. Other selections appeared subsequently, notably one (1897), by Miss L. I. Guiney. The Poems of James Clarence Mangan (1903), and the Prose Writings (1904), were both edited by D. J. O’Donoghue, who wrote in 1897 a complete account of the Life and Writings of the poet.


MANGANESE [symbol Mn; atomic weight, 54.93 (O = 16)], a metallic chemical element. Its dioxide (pyrolusite) has been known from very early times, and was at first mistaken for a magnetic oxide of iron. In 1740 J. H. Pott showed that it did not contain iron and that it yielded a definite series of salts, whilst in 1774 C. Scheele proved that it was the oxide of a distinctive metal. Manganese is found widely distributed in nature, being generally found to a greater or less extent associated with the carbonates and silicates of iron, calcium and magnesium, and also as the minerals braunite, hausmannite, psilomelane, manganite, manganese spar and hauerite. It has also been recognized in the atmosphere of the sun (A. Cornu, Comptes rendus, 1878, 86, pp. 315, 530), in sea water, and in many mineral waters.

The metal was isolated by J. G. Gahn in 1774, and in 1807 J. F. John (Gehlen’s Jour. chem. phys., 1807, 3, p. 452) obtained an impure metal by reducing the carbonate at a high temperature with charcoal, mixed with a small quantity of oil. R. Bunsen prepared the metal by electrolysing manganese chloride in a porous cell surrounded by a carbon crucible containing hydrochloric acid. Various reduction methods have been employed for the isolation of the metal. C. Brunner (Pogg. Ann., 1857, 101, p. 264) reduced the fluoride by metallic sodium, and E. Glatzel (Ber., 1889, 22, p. 2857) the chloride by magnesium, H. Moissan (Ann. Chim. Phys., 1896 (7) 9, p. 286) reduced the oxide with carbon in the electric furnace; and H. Goldschmidt has prepared the metal from the oxide by means of his “thermite” process (see Chromium). W. H. Green and W. H. Wahl [German patent 70773 (1893)] prepare a 97% manganese from pyrolusite by heating it with 30% sulphuric acid, the product being then converted into manganous oxide by heating in a current of reducing gas at a dull red heat, cooled in a reducing atmosphere, and finally reduced by heating with granulated aluminium in a magnesia crucible with lime and fluorspar as a flux. A purer metal is obtained by reducing manganese amalgam by hydrogen (O. Prelinger, Monats., 1894, 14, p. 353).

Prelinger’s manganese has a specific gravity of 7.42, and the variety obtained by distilling pure manganese amalgam in vacuo is pyrophoric (A. Guntz, Bull. Soc. [3], 7, 275), and burns when heated in a current of sulphur dioxide. The pure metal readily evolves hydrogen when acted upon by sulphuric and hydrochloric acids, and is readily attacked by dilute nitric acid. It precipitates many metals from solutions of their salts. It is employed commercially in the manufacture of special steels. (See Iron and Steel.)

Compounds

Manganese forms several oxides, the most important of which are manganous oxide, MnO, trimanganese tetroxide, Mn3O4, manganese sesquioxide, Mn2O3, manganese dioxide, MnO2, manganese trioxide, MnO3, and manganese heptoxide, Mn3O7.

Manganous oxide, MnO, is obtained by heating a mixture of anhydrous manganese chloride and sodium carbonate with a small quantity of ammonium chloride (J. v. Liebig and F. Wöhler, Pogg. Ann., 1830, 21, p. 584); or by reducing the higher oxides with hydrogen or carbon monoxide. It is a dark coloured powder of specific gravity 5.09. Manganous hydroxide, Mn(OH)2, is obtained as a white precipitate on adding a solution of a caustic alkali to a manganous salt. For the preparation of the crystalline variety identical with the mineral pyrochroite (see A. de Schulten, Comptes rendus, 1887, 105, p. 1265). It rapidly oxidizes on exposure to air and turns brown, going ultimately to the sesquioxide. Trimanganese tetroxide, Mn3O4, is produced more or less pure when the other oxides are heated. It may be obtained crystalline by heating manganese sulphate and potassium sulphate to a bright red heat (H. Debray, Comptes rendus, 1861, 52, p. 985). It is a reddish-brown powder, which when heated with hydrochloric acid yields chlorine. Manganese sesquioxide, Mn2O3, found native as the mineral braunite, may be obtained by igniting the other oxides in a mixture of nitrogen and oxygen, containing not more than 26% of the latter gas (W. Dittmar, Jour. Chem. Soc., 1864, 17, p. 294). The hydrated form, found native as the mineral manganite, is produced by the spontaneous oxidation of manganous hydroxide. In the hydrated condition it is a dark brown powder which readily loses water at above 100° C., it dissolves in hot nitric acid, giving manganous nitrate and manganese dioxide: 2MnO(OH) + 2HNO3 = Mn(NO3)2 + MnO2 + 2H2O. Manganese dioxide, or pyrolusite (q.v.), MnO2, the most important oxide, may be prepared by heating crystallized manganous nitrate until red fumes are given off, decanting the clear liquid, and heating to 150° to 160° C. for 40 to 60 hours (A. Gorgen, Bull. Soc., 1890 [3], 4, p. 16),