790 Z I T Z N A but also with basic oxides. For instance, if it be fused up with an excess of carbonate of soda, 2 of C0 2 are expelled by every Zr0 2 , with formation of ortho-zirconate (analogous to ortho-silicate) of soda, ZrO 2 .2Na 2 O. On treating the fuse with water we obtain the salt Na 2 0.8ZrO 2 + 12H 2 0, which crystallizes in hexagonal plates. Zirconic chloride, ZrCl 4 , is prepared, by igniting a mixture of zirconia and charcoal in a current of chlorine, as a white sublimate. It has the exact vapour-density corresponding to the formula. It dissolves in water with evolution of heat ; on evaporation a basic salt, 2ZrOCl 2 + 9H. ; 0, separates out in star-shaped aggregates of needles. Metallic zirconium is obtainable, by heating the double fluoride of zirconium and potassium with metallic potassium, as an iron-grey powder. Troost produced crystallized zirconium by fusing the double fluoride with aluminium in a graphite crucible at the temperature of melting iron, and extracting the aluminium from the fuse with hydro chloric acid. The crystals look like antimony and are brittle ; their specific gravity is 4 15. The powdery metal burns readily in air ; the crystalline metal requires to be heated in an oxyhydrogen flame if it is to catch fire. Mineral acids generally attack the crystallized metal very little even in the heat ; aqua regia, however, dissolves it readily, and so does hydrofluoric acid. The spark spec trum of zirconium is characterized by five lines, whose wave-lengths are as follows : 6127 in the red, and 4815, 4771, 4738, 4709, and 4686 in the blue. The atomic weight is not known exactly ; according to Marignac and Deville, it lies near 90, if O = 16. ZITTAU, the centre of the Saxon linen trade and the most populous town in the district of Bautzen, in the king dom of Saxony, is situated on the left bank of the Mandau, near its confluence Avith the Neisse, 25 miles south-east of Bautzen and 48 east-south-east of Dresden. The town is built in a regular and modern style. The town-house date.s from 1844, and contains a public library of 30,000 volumes. The church of St John was rebuilt in 1834-37; and the church of St Peter and St Paul, with its elegant tower, belonged to an old Franciscan monastery. The latter was restored in 1882 and part of it fitted up as an historical museum. There are five other churches in the town. Zittau is well equipped with schools, including a gymnasium (founded in 1586) and a commercial school, both accommodated in the Johanneum, and several techni cal institutions. The leading branch of industry is linen and damask weaving ; but woollen stuffs, trimmings, tfec., are also produced in the factories of the town, and in the surrounding weaving villages, 37 of which, with 70,000 inhabitants, are included in the municipal jurisdiction. The town, which is one of the best endowed in Saxony, also owns valuable forests on the mountains of Upper Lusatia. There are various steam-mills, iron-foundries, brick-fields, and potteries near the town, and extensive deposits of lignite, employing over 1000 hands. Zittau is situated near the border of Bohemia, with which it carries on some trade. In 1885 the population was 23,215, of whom less than one-fifth were Roman Catholics; in 1834 the population was 8508. Zittau is of Wemlish origin (Chytawa is its Wendish name), and was made a town by Ottocar II. of Bohemia. It was one of the six towns of the Lusatian league (1346), at which period it be longed to Bohemia. It suffered severely in the Hussite wars and in the Thirty Years War, and was bombarded and burnt by the Austrians in 1757 during the Seven Years War. The musical composer Marsclmer (1795-1861) was born at Zittau. ZIZKA, or ZISKA, JOHN (c. 1360-1424), leader of the HUSSITES (q.v.) from 1419, Avas born at Trocznow in the neighbourhood of Budweis in Bohemia about the year 1360. He was of noble descent, and was brought up from an early age at Prague at the court of King Wenceslaus. In 1410 he fought as a volunteer, on the losing side, in the great battle of Grunwakl, near Tannenberg in Prussia, in which the knights of the Teutonic Order were com pletely routed by the Lithuanians and Poles. He after wards took part in the Hungarian wars against the Turks, and is also said to have fought on the English side in the battle of Agincourt. In the discontents which followed the martyrdom of Huss and Jerome in Bohemia he sided with the liberal party, and ultimately, on the outbreak of hostilities, became its leader. He soon organized a for midable body of infantry, and from his newly fortified stronghold of Tabor as a centre achieved various successes, of which the most signal was the victory over the imperial troops at Deutschbrod (8th January 1422). At an early period of the war, at the siege of Raby in 1421, Zizka, who from boyhood had been blind of an eye, completely lost his sight ; but his strength of will enabled him almost wholly to overcome this formidable disadvantage, and his extraordinary presence of mind, fertility of resource, and keenness of mental vision, coupled with a zeal that was wholly sincere, though not always free from fanaticism, continued to mark him out as the leader in the cause he had espoused until his death, which was caused by an infectious disorder while he was besieging Przibislaw (llth October 1424). See Millauer, Di2)lomatisch-historische Aufsdtze ubcr JoJiann Ziska (1824). Zizka s life has been made the subject of an epic by the German poet Meissner (1846 ; 10th edition 1867), and has also been related in prose by George Sand. ZLATOUST, in the Russian government of Ufa, is one of the chief towns and iron-works of the Urals. It is situ ated on the Ai, a tributary of the Ufa, in a picturesque valley of the middle Urals, at a height of 1200 feet above sea-level. The 270 miles which stretch between Zlatoust and Ufa in the west will soon be covered by rail, while a branch line is projected to connect it with Ekaterinburg in the north. The town is well built, mostly of wood, has a first-class meteorological and magnetic observatory, and is the seat of the mining administration for the Zlatoust district, which includes, besides several iron-works, the rich gold-washings of the basin of the Mias. Its merchants carry on a brisk trade in agricultural produce and cattle, as well as in manufactured wares, imported for the use of the mining villages of the neighbourhood. The Ai and several ponds supply the crown iron -works with motive power, and in 1884 the iron furnaces of Zlatoust yielded 90,800 cwts. of pig-iron, which were used almost entirely for the manufacture of swords, bayonets, and artillery munition. The population of Zlatoust in 1884 was 19,000. ZNAIM, or ZNAYM (Czech Znojmo), an interesting old town of Moravia, is picturesquely situated on the left bank of the Thaya, 45 miles north-north-west of Vienna. The town proper is adjoined by four suburbs, and it contains three fine open squares, while the site of the old fortifications is occupied by a pleasant promenade. The Rjiuberthurm is a relic of the old castle of the margraves of Moravia ; the round castle-chapel, known as the heathen temple (Heiden-Tempel), in the Romanesque style of the 12th century, was at one time considered the most ancient building in Moravia. The Gothic church of St Nicholas was built about 1348 by the emperor Charles IV. ; the town-house, with an elegant Gothic tower, 250 feet high, dates from about 1446. The ancient and once powerful Prsemonstratensian abbey of Bruck, to the east of the town, is now occupied as barracks. The town is well equipped with technical and other schools, and carries on manufactures of earthenware, leather, chocolate, vinegar, and other articles. Large quantities of cucumbers, grain, and wine are produced in the fertile environs. In 1880 the population, chiefly of German origin, was 12,254.
The present town of Znaim was founded in 1226 by Ottocar I. of