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 ALTON — ALUMINIUM Adtoai, a city of Madison county, Illinois, U.S.A., situated in the western part of the state, on the eastern bank of Mississippi river, just above the mouth of Missouri river, and twenty-one miles above St Louis, at an altitude of 436 feet. It is built on the river bluffs, and its plan is fairly regular. It is entered by four railways. The population in 1880 was 8975, in 1890 it was 10,294, and in 1900 it was 14,210. AStOUcl, a town of Prussia, province Schleswig-Holstein, immediately W. of Hamburg, with which it is commercially identified, though administratively it is a separate town. Municipal offices, a bronze equestrian statue of the Emperor William I., and a bronze statue of Bismarck have been erected; there may also be noticed the public museum (containing ethnographical and natural history collections), and monuments of the wars of 1864 and 1870-71. Altona is the headquarters of the 9th German army corps, and possesses a school of navigation and famous fish-markets. Among its industries are the production of cottons, woollens, chemicals, chicory, hats, and varnish. Since 1888, when Altona joined the Imperial Zollverein, approximately half a million sterling has been spent upon harbour improvement works. The imports and exports resemble those of Hamburg (q.v.). In the ten years 1871-80 the port was entered on an average by 737 vessels of 67,735 tons, in 1881-90 by 608 vessels of 154,713 tons, and in 1891-98 by 839 vessels of 253,384 tons. In 1889 Ottensen (to the W. of Altona), where the poet Klopstock lies buried, was incorporated with the town. In 1885 (including Ottensen, Oevelgonne, Othmarschen, and Bahrenfeld) the population was 126,306 ; in 1895, 148,944 ; in 1900, 161,508; without the four suburbs, 113,526 (1895); 117,824 (1900). Altoona, a city of Blair county, Pennsylvania, U.S.A., situated in 40° 32' H. lat. and 78° 24' W. long., at the foot of the Allegheny plateau, not far from the centre of the state, at an altitude of 1179 feet. It is on the main line of the Pennsylvania railway. The city is divided into nine wards, is regularly laid out, and is well built, having been in great part constructed by the railway corporation as its chief manufacturing depot. Fostered by the railway, it has had a very rapid and solid growth. The population in 1880 was 19,710, in 1890 it was 30,337, and in 1900 it was 38,973 AItrincha.m, or Alteingham, a market town and railway station in the Altrincham parliamentary division of Cheshire, England, 8 miles S.W. by S. of Manchester. The more recent structures are a Baptist chapel, a Unitarian chapel, and a market hall. Area of township (an urban district), 662 acres. Population (1881), 11,250; (1891), 12,440; (1901), 16,831 ; of parliamentary division (1901), 78,796. Altwasser, an industrial village of Prussia, province Silesia, 43 miles by rail S.W. from Breslau, and 3 N. from Waldenburg. It has factories for glass, porcelain, machinery, cotton-spinning, iron-foundries, and coal-mines. Population (1885), 8672; (1895) 10,207. ASty n-tagh J or Astyn-tagh, a lofty mountain range of central Asia, running from the S.W. to the N.E., from 38° 17.-871° E. to 39° H.-910 E., forms a border range of Northern Tibet, having to the noffh-west the lower terrace of the East Turkestan plateau, about 2700 feet high on the banks of the Cherchen-daria, and to the south-east the northwestern extremity of the Tsaidam plateau, nearly 10,000 feet of altitude. In 89° 30' E. it is separated from the Tarim basin by a secondary chain, about 7200 feet high, but farther west it rises above the desert as a nearly vertical wall. The passes visited by Prjewalsky and Carey reach

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10,140 and 13,000 feet respectively, the summit attaining from 12,000 to 14,000 feet. (See Kuen-lun.) A it-Z alb rZGj a village of Prussia, province of Silesia, 5 miles by rail E. from Gleiwltz. It is in repute for its iron-works, coal-mines, manufactory of wire ropes, &c. Population (1885), 9390; (1895), 14,012 ; (1900), 19,571. Aluminium.—Although never met with in the elemental state, the metal aluminium is more widely distributed throughout the world than any similar substance. The word is derived from the Latin alumen, and is probably akin to the Greek aXs (the root of salt, halogen, etc.); but while Pliny the Elder and other Roman authors discuss its properties at some length, there is considerable doubt whether the alum they knew was not largely composed of sulphate of iron. In the 16th century A.D., Paracelsus drew the first real distinction between alum and the vitriols; in 1722 Hoffmann announced the base of alum to be an individual substance ; in 1761 Morveau suggested that this base should be called alumine, after Sel alumineux, the French name for alum; and finally about 1820 the word was changed into alumina. In 1760 the French chemist Baron unsuccessfully attempted “to reduce the base of alum” to a metal, and shortly afterwards various other investigators essayed the problem in vain. In 1808 Sir Humphry Davy, fresh from the electrolytic isolation of potassium and sodium, strove to break up the molecule of alumina by heating it with potash in a platinum crucible and submitting the mixture to a current of electricity; in 1809, with a more powerful battery, he raised iron wire to a red heat in contact with alumina, and obtained distinct evidence of the production of an iron-aluminium alloy. Naming the new metal in anticipation of its actual birth, he called it alumium; but for the sake of analogy he was soon persuaded to change the word to aluminum, in which form, alternately with aluminium, it occurs in chemical literature for some thirty years. The metal is occasionally called aluminum in America to this day ; but the European spelling is preferable, as the termination -ium harmonizes with the names of other metallic elements. In the year 1824, endeavouring to prepare it by chemical means, Oersted heated its chloride with potassium amalgam, and failed in his object simply by reason of the mercury, so that prepara. when Wohler repeated the experiment at Gottingen in tjon 1827, employing potassium alone as the reducing agent, he obtained it in the metallic state for the first time in history. Contaminated as it was with potassium and with platinum from the crucible, the metal formed a grey powder and was far from pure ; but in 1845 he improved the conditions of his process, and succeeded in producing metallic globules wherewith he examined its chief properties, and prepared several compounds hitherto unknown. Early in 1854, H. St. Claire Deville, who was attempting to make some non-existent salts of aluminium, accidentally and in ignorance of Wohler’s later results, imitated the 1845 experiment. At once observing the reduction of the chloride, he realized the importance of his discovery, and immediately began to study methods for winning the metal on a commercial scale. His attention was at first divided between two processes—the chemical method of reducing the chloride with potassium, and an electrolytic method of decomposing it with a carbon anode and a platinum cathode, which was simultaneously imagined by himself and Bunsen. Both schemes appeared well-nigh impossible : potassium cost about £17 per lb, gave a very small yield, and was dangerous to manipulate, while on the other hand, the only source of electric current then available was the primary battery, and zinc as a store of industrial energy was utterly out of the question. Deville accordingly returned to pure chemistry and invented a practicable method of preparing sodium which, having a lower atomic weight than potassium, reduced a larger proportion. He next devised a plan for manufacturing pure alumina from the natural ores, and finally elaborated a process and plant which held the field for almost thirty years. So admirably and exhaustively were his researches conducted that it required a Castner to improve on his methods. Only the discovery of dynamo-electric machines and their application to metallurgical processes rendered it possible for the brothers Cowles to remove the industry from the hands of chemists, till the time when Messrs. Heroult and Hall, by devising the electrolytic