Page:Collier's New Encyclopedia v. 10.djvu/579

LEFT ZINC 499 ZION soluble in water and alcohol. Sulphate of zinc, or white vitriol, is manufactured on a large scale by roasting native sul- phide of zinc (blende), extracting the mass with water, and evaporating to the crystallizing point. It is generally sent into commerce in white fused masses. Generally speaking, it contains six atoms of water of crystallization; but com- pounds containing less have been formed. It crystallizes ordinarily in four-sided prisms. It is used in medicine as an emetic, and very largely by calico print- ers. It is soluble in 2V2, parts of water, but insoluble in alcohol. Several basic sulphates are said to exist. It combines directly with ammonia, forming a defi- nite compound. It also forms double sul- phates with those of potassa, ammonia, magnesia, and protoxide of iron. Car- bonate of zinc, or calamine, occurs in nature in large amorphous masses, and occasionally in crystals of the same form as those of carbonate of lime. It is the chief ore of zinc, and is employed in its impure state in medicine as an exsiccant, and in healing cerates. The anhydrous carbonate may be prepared in the labora- tory by placing a tube containing carbon- ate of soda in a strong tube containing sulphate of zinc, sealing the outer tube hermetically, heating it to 320° F., and inverting it so that the solution may mix; crystalline grains of the anhydrous carbonate are gradually deposited. No neutral carbonate of zinc can be obtained from its salts by double decomposition. Chloride of zinc is prepared by dissolv- ing granulated zinc in hydrochloric acid, and evaporating, when it is obtained in a semi-solid hydrated mass, known as butter of zinc. If this be further heated, it fuses, becomes anhydrous and solid. It is deliquescent, fuses easily, and may be distilled. It is remarkably soluble in water, and its strong affinity for that substance renders it of great use as a desiccating agent in organic research. In solution it forms Burnett's disinfect- ing fluid. It is a powerful escharotic when applied to the skin, and is used in surgery for that purpose. It fuses above 700° F., but does not decompose unless more strongly heated; hence a bath of it is sometimes used for maintaining ob- jects at a high temperature. Its solution absorbs ammoniacal gas with avidity. It forms double salts with the chlorides of the alkaline metals. Its solution is also much used in soldering zinc, iron, and copper. Its solution is also much used for preserving objects for dissec- tion, as it does not corrode the instru- ments in the same way as corrosive sub- limate. Several oxychlorides are said to exist. Sulphide of zinc, or blende, is found native contaminated with a large number of the other metals. It may be prepared by the direct combination of its elements. The hydrated sulphide is ob- tained as a white precipitate, by adding an alkaline sulphide to a solution of some zinc salt. There are several oxy- sulphides of zinc. The trisilicate of zinc, or electric calamine, is found native in several parts of the world. Heat de- velops electricity in it; hence its name. Valerianate of zinc is used in medicine in combating nervous disorders. The production of spelter in the United States in the calendar year 1900 was 123,886 short tons, the largest on record. Illinois, Indiana, Kansas, and Missouri were the chief producing States. For the first time the United States be- came the exporter of both metal and ore in that year. The production of primary zinc in the United States in 1919 was 452,272 short tons, valued at $66,032,000. Okla- homa ranked first in the production of zinc, with 121,988 tons; Illinois was second, and Kansas third. In 1919 the United States produced practically all the zinc smelted. Zinc imports in that year amounted to 48,649 tons of ore, 17,009 tons of zinc content, with a total value of $529,660. The exports of zinc in 1919 were valued at $50,530,132. ZINGIBERACE.ffi. gingerworts ; an order of endogens, the typical one of the alliance Amomales. Aromatic herbs, with a creeping, often jointed rhizome. Stem simple, formed of the cohering bases of the leaves ; leaves simple sheath- ing, with a single mid-rib, Ixova. which very numerous parallel veins diverge at an acute angle and proceed to the mar- gin; flowers generally in pairs, and lying among spathaceous bracts; calyx supe- rior, short, tubular, three-lobed; coroUa, tubular, irregular, with six segments in two whorls, the inner, morphologically viewed, being transformed sterile sta- mens, untransformed stamens three, two of them abortive; filament of the former not petaloid; anther, two-celled; style filiform; stigma, dilated, hollow; ovary, more or less perfectly three-celled, with the placenta in the axis; fruit, usually a capsule, three, or sometimes one celled; seeds, many. Closely akin to Maran- tacese, with which they were formerly combined, but differ in their two-celled anther, and in the possession of a vi- tellus round the embryo. Natives of the East Indies and some other tropical countries. Genera, 29; species. 247. ZION. or SION, the highest and most S. mount of Jerusalem ; rising about 2,500 feet above the Mediterranean, and from