ZION CITY 500 2ISKA OF TBOCNOW 200 to 300 feet above the valleys at its base. It was separated from Akra on the N. and Moriah on the N. W. by the Valley Tyropoeon; and had the valley of Gibbon on the W., that of Hinnom on the S., and that of the Kidron on the S. E. It was a fortified town of the Jebusites till subdued by David, and thence forward was called the "City of David." A mosque near its S. brow now covers the "tomb of David" so called, most jealously guarded by the Moham- medans. This mount, together with Moriah and Ophel, was inclosed by the first wall, and fortified by citadels. On it were erected the magnificent palaces of Solomon, and long afterward those of Herod. At the present day a consider- able portion of it lies outside of the modem wall on the S. "Zion," and "the daughter of Zion," are sometimes used in Scripture to denote the whole city, including especially Moriah and the Temple; and sometimes figuratively for the seat of the true Church on earth and in heaven. ZION CITY, a city of Illinois, in Lake CO. It is on the Chicago and North- western railroad. It was founded by Charles Alexander Dowie. The industries of Zion City include the manufacture of lace goods, electrical supplies, office sup- plies, candy, baking supplies, etc. Pop. (1910) 4,789; (1920) 5,580. ZIONISM, a name given to the plan for the acquisition of Palestine, with a view to establishing the Jews in the Holy Land. This ambition was to an extent realized following the World War, when Palestine became a protectorate of Great Britain, which officially assented to the establishment of a Jewish state. See Palestine. ZIPHIUS, a genus of whales belonging to the family of the Rhynchoceti, or beaked whales. Ziphius occurs in the Mediterranean Sea and South Atlantic. The snout is pointed, there is a single blow-hole, and a small dorsal fin is de- veloped. There are no teeth in the upper jaw, but the lower jaw is provided with from one to two pairs. Z. Sowerbiensis is a familiar species. The average length is 16 feet. ZIRCON (Zr02, Si02), a mineral, sili- cate of zirconium,, originally found in Ceylon, and forming one of the gems, being met with either colorless or col- ored — red, brownish-green, etc. Hya- cinth and jargon are varieties. ZIRCONIA (ZrO=), the oxide of zir- con, a hard white solid, "sticks" of which are sometimes used in the oxyhydrogen flame instead of lime. ZIRCONIA LIGHT, an intensely brilliant light differing from the Drum- mond light mainly in the employment of cones of the oxide of zirconium instead of the less durable cylinders of lime. In 1867 Tessie du Motay introduced this light into Paris, and it was there em- ployed for several years to illuminate squares and public buildings and gar- dens. The cones were formed of burnt zirconia kneaded into a paste withaque- ous boracic acid, and hardened in iron molds at a red heat, and a mixture of oxygen and a highly carburetted gas was burnt to raise the cones to incandescence. The light was also once used as an illu- minant in public places of Brussels and Vienna, and in the United States in light- houses and public works. ZIRCONIXJM, Zr=89:6; a somewhat rare metal, intermediate in many of its properties to aluminum and silicum. Its oxide, zirconia, was first prepared by Klaproth in 1789 from the mineral zir- con, which is essentially a silicate of zir- conium, and is found crystallized in square prismatic or octahedric crystals. ZIRKNITZ, or CZIRKNICZ (tsirk' nits), a lake of Austria; in Camiola, 30 miles E. N. E. of Trieste; about 5 miles long and between 2 and 3 broad, without surface outlet. It is remarkable for the occasional disappearance of its waters for weeks and even months, during which its bottom is often covered with luxuriant herbage. Its bed is composed of limestone, and full of deep fissures and caverns through which the waters disappear, returning when the rain sets in. ZISKA OF TROCNOW, JOHN, a Hussite leader; born of noble parents, in Trocnow, Bohemia, about 1360. He spent his youth as a page at the court of King Wenceslaus; in 1410 joined the troops that marched from Bohemia and Hungary to help the Teutonic knights against the Poles and Lithuanians; and took part in the battle of Tannenberg, July 15. After this he fought in the campaigns of the Hungarians against the Turks, and on the side of the English against the French, especially distin- guishing himself at Agmcourt (1415). On his return to Bohemia, he attached himself to the extreme party of the Hus- sites, who under his leadership quickly became trained soldiers, and learned to fortify their camps by "Wagenburgen," i. e., wagons so placed as to form defen- sive squares. In 1421 he founded a for- tress on Mount Tabor, on July 14 of that year he defeated the German crusading army on the mountain ever since called Ziskaberg, and in January, 1422, he de-
