Page:Encyclopædia Britannica, Ninth Edition, v. 17.djvu/529

I C N I C 487 contains a portrait of him at the age of eighty and several well-earned tributes to the worth of his busy and fruitful life. He died November 26, 1826. NICHOLSON, WILLIAM (1753-1815), a writer on natural philosophy, was born in London in 1753, and after leaving school made two voyages as midshipman in the East India service. He subsequently entered an attorney s office, but, having become acquainted, in 1775, with Wedgwood, he resided for some years at Amsterdam as agent for the sale of pottery. On his return to England he was induced by Holcroft to devote himself to the com position of light literature for periodicals, assisting that writer also with some of his plays and novels. Such work was little in accordance, however, with his scientific tastes, and he employed himself on the preparation of An Intro duction to Natural Philosophy, which was published in 1781, and was at once successful. A translation of Voltaire s Elements of the Neivtonian Philosophy soon followed, and he now entirely devoted himself to scientific pursuits and philosophical journalism. In 1784 he was appointed secretary to the general chamber of manu facturers of Great Britain, and he was also connected with the society for the encouragement of naval architecture, established in 1791. Besides his literary labours, he bestowed much attention upon the construction of various machines for comb-cutting, file-making, cylinder printing, &c. ; he also invented an aerometer. In 1800 he com menced in London a course of public lectures on natural philosophy and chemistry, and about this period he made the discovery of the decomposition of water by the agency of galvanism, which was said to be the foundation of Sir Humphrey Davy s discoveries in the decomposition of the alkalins. In 1797 the Journal of Natural Philosophy, Chemistry, and the Arts, generally known as Nicholson s Journal, the earliest work of the kind in Great Britain, was begun; it was carried on till 1814. During the later years of his life Nicholson s attention was chiefly directed to engineering works at Portsmouth, at Gosport, and in Southwark ; these with his other employments placed him in an affluent position, which, however, from domestic and other causes, he was unable to maintain. He died in poverty in 1815. A memoir was written by his son long after his death, but it never was published. Besides considerable contributions to the Philosophical Transactions, Nicholson wrote translations of Four- croy s Chemistry (1787) and Chaptal s Ckentittry (1788), First Prin ciples of Chemistry (1788), and a Chemical Dictionary; he also edited the British Encyclopaedia, or Dictionary of Arts and Sciences, 6 vols. 8vo, London, 1809. NICHOLSON, WILLIAM (1784-1844), portrait-painter, was born at Newcastle-on-Tyne in 1784. Having settled in Edinburgh, he became, along with Thomas Hamilton the architect, one of the founders and most vigorous pro moters of the Scottish Academy, of which in 1826 he was appointed the first secretary, a position which he held for about seven years. He is known by his life-sized portraits in oils, and still more favourably by his very delicate and faithful likenesses in water-colours. In 1818 he published a series of etchings entitled Portraits of Distinguished Living Characters of Scotland. They are executed in an effective and painter-like fashion, mainly from the artist s own water-colours, and include portraits of Sir Walter Scott, Lord Jeffrey, Robert Burns, and Professor Wilson. Nicholson died at Edinburgh on August 16, 1844. NICIAS was the leader of the aristocratic party at Athens and one of the foremost figures in Athenian history during the Peloponnesian War. Although he opposed the democratic tendencies which gave the tone to Attic politics at this time, his high character for piety and honesty, combined with his wealth and influence, gained the con fidence of the people, and raised him to the highest offices in their gift. His abilities were not equal to the duties he was called on to perform, and in the severe trial of the Sicilian expedition his conduct showed such timidity in critical situations, such wavering in the general plans of warfare, such obstinacy in details where piety or supersti tion were concerned, that the disastrous end of the siege of Syracuse must be mainly laid to his charge. It is unnecessary here to write his life, a task which would be almost equivalent to writing the history of Athens for a number of years. See GREECE, vol. xi. p. 102. NICKEL, a chemical term, designating a metallic element which was discovered by Cronsted in 1751. In 1754 he succeeded in isolating it (in an impure state), and found it to be a "halbmetall" (semi-metal). After wards finding it to be present largely in " kupfer-nickel," * he borrowed from that mineral the name for his new element. Nickel (Ni) is one of the less abundant of elements. It is contained in the sun s atmosphere and in all meteoric iron. Of nickel minerals the following are of metallurgic importance : nickel-blende, NS ; arsenical nickel glance, Ni(As . S) 2 ; niccolo-cobaltic pyrites, (Ni, Co, Fe) 3 S 4 ; garnierite, 5(Ni, Mg)0 . 4SiO 2 + f H 2 O. Almost invari ably part of the nickel is replaced by cobalt, and not unfrequently part of the arsenic by antimony, or occasion ally bismuth. Nickel ores are in general complex mixtures of one or more of these minerals, with sometimes very large proportions of copper, iron, and other foreign metallic ores and gangue. The metallurgy of nickel accordingly is a complex subject which cannot be fully treated here. As an example of a sulphureous ore may be quoted that niccolo- cupreous pyrites which is being worked at Dillenburg in Nassau. The process employed is closely analogous to the old process of copper-smelting as explained in METALLURGY (vol. xvi. p. 61). The fully refined mat ("Concentrations-Stein ") consists of 35 per cent, of nickel, 43 of copper, 2 of iron, and 20 of sulphur. The article METALLURGY (ut sup.), under arsenides, describes a process which, when applied to arseniferous cobalt and nickel ores, yields the cobalt as smalt, the nickel as part of a "speis" (an alloy of arsenides). The same process serves occasionally for (so to say) collecting small proportions of nickel diffused throughout oxidized ores, the arsenic requisite being introduced in the form of native arsenide of iron. If an arseniferous ore contains copper, the process sometimes is modified by addition of iron pyrites or some other sulphureous material, and so conducted that, in addition to a nickelous speis, a cupreous mat is produced. The speis and mat do not mix, but form separate layers, the mat, as the lighter of the two, going to the top. All sulphureous, arsenical, or poor oxidized nickel ores are being wrought by methods analogous to the above, in so far at least as they all aim, in the first instance, at the production of a speis or mat from which the metal has to be extracted by subsequent operations. Direct methods are being used only in conjunction with one kind of ore, namely, that rich oxidized nickel ore which was discovered in New Caledonia about 1875, and has since been imported into Europe in large and yearly increasing quantities. It occurs in veins within serpentine, and consists of garnierite mixed with more or less of oxide of iron, chrome-iron ore, and a little black oxide of cobalt. It is valuable chiefly through its absolute freedom from arsenic and sulphides. Most of the ore goes to France, where it is worked chiefly by two firms. Christofle at St Denis treats the ore with hydrochloric acid, and from the solution recovers the metal by methods analogous to those customarily employed in^con- nexion with speis and mats. Gamier, at the Septemes Works near Marseilles, makes straight for the metal. The powdered ore, after mechanical purification (by such methods as are explained in METALLURGY, vol. xvi. p. 59), is mixed with charcoal and fluor-spar (or other flux) and worked into a paste with coal-tar, which is then shaped into bricks or walnut-sized stones. The ore thus prepared is then manipulated pretty much in the same way as an iron ore is for the production of pig-iron. The furnaces used are about 13 feet high, and worked with cold wind. Gamier in this manner produces three kinds of metal : (1) an almost pure carbide of nickel, which needs only be decarbonized to be converted into pure metal ; (2) an alloy of the carbides of nickel and iron ; and (3), from mixtures of nickel and iron ore, a nickeliferous pig-iron which, 1 Said to be originally a term of contempt "goblin copper," mean ing a tricky ore, which promises copper but does not yield it.