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Zebu (Bos indicut).

in India have been bred for specific purposes, resulting in several races, useful for milk, draught, riding, etc. White bulls when branded with the image of Siva are held especially sacred by the Hindus: they are free from labor and restraint, and are not molested even when they commit depredations.

Zebulun. Tenth son of the patriarch Jacob, and ancestor of one of the twelve tribes of Israel.

Zeeharfali. Jewish prophet, author of 38th O. T. book, ab. 520 B.C., written to encourage the despondent Jews after the return from Babylon. Chapters ix.-xiv. are perhaps much older.

Zcdekiah. Last king of Judah 598-588 B.C.; son of Josiah. Rebelling against Nebuchadnezzar of Babvlon, his suzerain, he saw Jerusalem taken, the temple burneJ, his sons slain, and was then blinded and carried to Babylon, there to die in prison. Jer. xxxiv. 2-5.

Zedlitz, Joseph Christian Von, 1790-1862. Austrian poet and dramatist.

Zedoary. Name given to the roots of several species of Zingiber and Curcuma, native of China and Bengal, resembling ginger in its qualities, but now entirely replaced by the latter.

Zeeland. See Zealand.

Zcishcrscr, David, 1721-1808. Moravian missionary among the Indians of Pa. and Ohio; abundant in labors and sufferings. Delaware Dictionary, 1887; Onondaga Grammar, 1888; Diary, 1888.

Zelaya, Jose Santos, b. ab.1845. Pres. of Nicaragua 1893.

Zell, Bernhard, 1715-1779. German traveler in Mexico and Cal. His Reisen, 1771-72, indicated the existence of gold in Cal.

Zell, Matthaus, 1477-1548. Reformer at Strasburg.

Zeller, Eduard, b.1814. Prof, of Theology at Berne 1847 and Marburg 1849, of Philosophv at Heidelberg 1802 and Berlin 1873-94. Philosophy of the Greeks. 1844-52 and later, tr. in 6 vols. 1868-83; Hist. Apostles, 1854, tr. 1875-76; Strauss. 1874.

Zeller, Jules Sylvain, b. 1820. Prof. Paris 1858; historical writer: especially on Italy and Germany.

Zeller, Karl Friedrich, 1758-1832. German musician, teacher of Mendelssohn; conductor Singakademie in Berlin; founder Royal Institute for church music 1809.

Zenana. Harem or women's apartments in India.

Zend. Old Persian dialect, sometimes called Old Bactrian, in which was written the sacred book of Zoroaster, the Avesta (q.v.). It comprised three books of verse, hymns, prayers, and laws.

Zendejas, Miouel Geronimo, 1724-1816. Mexican painter, self-taught.

Zenea. Joan Clemente, 1834-1871. Cuban lyric poet and patriot; executed.

Zenith. Point where the plumb-line produced upward pierces the celestial sphere.

Zenitb Distance. That of a star from the zenith, measured on a great circle.

Zenith Telescope. Instrument much used for determination of latitude. It consists of a telescope having an altitude and azimuth mounting, provided with a delicate level and mi crometer, by means of which the difference of zenith distance

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Combination Transit and Zenith Telescope.

of two stars may be measured. These stars are so selected that one culminates n. of the zenith, the other s. at approximately equal zenith distances. The measurements so made with the declinations of the stars furnish data for determining the latitude.

Zenker, Jonathan Karl, 1799-1837. Prof. Jena 1828. Die Pflanzen und ihr wissenschaftlich.es Studium iiberhaupt, 1830: Merkantilische Waarenkunae, 1831-35.

Zeno, 5th cent. B.C. Philosopher of Elea, s. Italy; pupil of Parmenides; famous for his denial of the existence of motion and for the paradoxical illustrations of Achilles and the Tortoise, and of the flying arrow, to prove his position.

Zeno, ab.850-260 B.C. Philosopher of Cyprus, founder of the Stoic school or "Porch" at Athens ab. 312 B.C.

Zeno, d.491. Byzantine Emperor 474; Isaurian; son-in-law of Leo I.

Zeno, Apostolo, 1668-1750. Italian dramatist, poet, and critic. Plays, 10 vols., 1744; Epistole, 6 vols., 1785.

Zeno, Nicolo. ab.l340-ab. 1391. Venetian seaman, said to have visited Greenland, Newfoundland, and coasted as far s.as Virginia.

Zcnobia. Wife of Odenathus, King of Palmyra. Queen of the East 266; defeated and made prisoner by Aurelian 272; led in his triumph 274.

Zenon dc Rouvroy, Charles Albert, 1098-1759. French writer on the American colonies.

Zenteno, Carlos De Tapia, 1698-ab.l770. Prof. Mexico: writer on Aztec language.

Zenteno, Jose Iqnacto, 1785-1847. Chilian general and minister of war, active against Spain.

Zeolite. Group of minerals, including a number of species,

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Ziggerat. Artificial hill intended for sacred uses in old Babylonia; usually constructed with seven platforms, but sometimes with two. There is no evidence that the different stories were painted in different colors, as has been asserted, or that the use was necessarily astronomical. It may be regarded simply as an attempt to reproduce a mountain. The Tower of Babel was unquestionably a ziggerat.

Zig-Zag. Molding peculiar to Norman style of architecture, of considerable variety.

Zigzag Riveting. Riveted joints where the rivets in parallel rows are placed alternating with each other, thus making a tight joint. See Chain Riveting.

Zigzagf*. Approaches constructed from the parallels in siege operations to reach the covered way of the besieged position. Their general direction is along the capitals of the bastion or polygonal work to be attacked. Each branch is directed obliquely to the front, so as to pass to the front of any position which the enemy can occupy to enfilade them. They are constructed by the flying, full, or double-sap, under the direction of the engineer officers charged with the conduct of the siege. See Siege.

Ziller, Tuiskon, 1817-1882. Prof. Leipzig 1864; writer on pedagogy and ethics.

Zillertlial. Tyrolese valley, n. of that of the Inn; 400 Protestants were expelled from it 1837.

Zilpall. Handmaid of Leah and inferior wife of Jacob; ancestress of the tribes of Issachar and Zebulun.

Zimb. Venomous dipterous insect found in Abyssinia, resembling and related to the Tsetse (q.v.).

Zimbabwe, or Zimbabwe. Remarkable ruins in British S. Africa, to the s.e. of Fort Victoria, in 20" 16' 30" S., and 31° 7' 30" E., at an altitude of 3,340 ft. The ruins evidently formed a garrison for the gold-producing race in remote antiquity, of whose work many traces have been found.

ZlmUces, John, 925-976. Byzantine Emperor 969-976. His abundant coins show the head or figure and titles of Christ, instead of his own.

Zimmerman. Johann Georg Von, 1728-1795. Swiss physician and author of vast repute in his day. His Solitude, 1755, was widely read.

Zfll. N.e. part of the wilderness in which the Israelites wandered in coming out of Egypt.

Zine. Zn. Element. At.wt. 65.3, valence II.; mentioned first by Basil Valentine, and Paracelsus, 15th century. White metal with a bluish-gray tint, malleable between 100° and 150° C, but crystalline and somewhat brittle below 100°, and brittle as glass above 200° C. Sp.gr., cast 6.9, rolled or hammered 7.2 to 7.3; nipt. 424° C.; bpt. ab. 1,000° C; sp.ht. 0.0956(0 to 100° C). Heated to bright redness, it takes fire in the air and burns with a greenish-blue light to white flakes of oxide (Philosopher's wool). When exposed to moist air it becomes coated with a basic carbonate. It is soluble in the common acids and in sodium and potassium hydroxides.

Zine, Metallurgy Of. The principal zinc ores are as follows: Zincblende or sphalerite, a zinc sulphide, ZnS, containing 67 per cent of zinc when pure, but carrying up to 18 per cent of iron and to 3 of cadmium. It is found in many countries, and very abundantly in Mo. Zincspar or smithsonite is a carbonate, ZnCO,, carrying 52 per cent of zinc. Calamine is a hydrous silicate, 2ZnO.SiOj,HjO, occurring in white, knuckle-like bunches of crystals. Similar-looking smithsonite is often erroneously called calamine. Willemite is anhydrous silicate, 2ZnO.SiOs. Zincite is red oxide, ZnO, its color being due to iron and manganese. Franklinite is a black mineral like magnetic iron ore, and consists of oxides of zinc, iron and manganese. The latter three minerals are found abundantly only in n. N. J. These minerals all have value as orss of zinc; they occur in many forms and under many diverse geological conditions. There are also other minerals, less common, in which zinc is an essential constituent.

The principle on which the smelting of zinc ores is based is the reduction of the oxide ore by carbon in a closed retort, and condensing the zinc vapors driven off. If the ore is a sulphide ore, it must first he roasted to oxide as a preliminary to reduction. This volatilization of the zinc is practically inevitable, because, under atmospheric pressure, zinc boils at a temperature less than is required for the reduction of its oxide. The temperature of reduction is a bright reddish yellow, ab.l,150° C, while zinc boils at ab.l,000° C.

When a mixture of oxidized zinc ore with granulated carbon is heated, it is probably not the carbon which directly abstracts oxygen from the ore, since such action could take phice only at the few points of contact of carbon and ore; hut the small amount of air always present forms with the carbon carbonic oxide, which reduces the ore over all its surface, forming car

bonic acid gas. The latter is reduced back by carbon tocarbonic oxide, and thus the cycle continues.

The roasting of sulphide ore (black-jack ore) to oxide requires considerable care. The finely-divided ore is heated slowly to bright redness in a roasting furnace, with excess of air admitted, being continually turned over. At a low heat, the sulphide forms largely sulphate, ZnS04, which at a higher heat splits up into ZnO and SO,, the former being then suitable for reduction.

The original form of apparatus for reducing zinc ores is no longer in use. It was called the English process, and consisted of crucibles in which the charge was heated, with tightly fitting covers, and a pipe passing through a hole in the bottom and reaching above the charge and below the crucible into a clear space below the fire; the lower part of the tube serving as a condenser for the zinc vapors driven off the charge, whose only outlet was through the pipe. The melted metal condensed in the tube trickled down into pots set beneath. The capacity of the crucibles was so small, and the consumption of fuel so great, that the process could not compete with the muffle and retort furnaces.

In Belgium, cylindrical or oval retorts are used, placed ab. 100 in a furnace, as shown in Fig. 1, where a is the charge in

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Fig 1 —Retorts, R ceivers, and Prolongs.

the retort; b the condenser, in the hollow of which the liquid zinc accumulates; c the prolong in which zinc vapor is still further caught as a blue powder. Only ab. 20 to 30 lbs. of ore is treated at once in a muffle, the operation requiring 10 to 12 hours. Usually only three-quarters to four-fifths of the metal in the ore is extracted, the cost of working being ab. two and a half cents per lb. of zinc. The price paid for the ore averages one cent per lb. of zinc contained. With the older furnaces, fired by coal, the fuel consumed was a considerable item of expense; the modern furnaces are longer and fired by gas, thus effecting considerable economy in fuel, its well as causing a less rapid destruction of the muffles.

In Silesia the muffles are several times as large, and are called retorts. In Fig. 2 is shown the retort A, the condenser a, and

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their situation in the furnace. Each furnace contains ab. 24 of these retorts, each taking 60 lbs. of calcined ore, with carbon, skimmings of metal, etc. The operation takes ab. 24 hours; gas firing is used in all the recently-constructed furnaces.

The zinc made in these furnaces is usually pure enough to go at once to the market. If a greater degree of purity is needed, the metal may be re-distilled, but a cheaper method is to melt it in a large pot and allow it to cool quietly and slowly. Lead sinks to the bottom and accumulates, while iron combined with some zinc falls to the bottom as a sandy residue; the purer zinc is ladled from the surface.

In Europe, Silesia and Belgium have long been large producers of zinc, and zinc ores are abundant in Italy and in Spain.

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by heating potassium fluozirconate with aluminium, as amorphous black powder or in crystalline metallic leaflets, occurs in nature chiefly as zircon, ZrSiO,.

Zirconium Bromide. ZrBr,. White, crystalline powder, decomposed by water; made like the chloride.

Zirconium Chloride. ZrCI,. White substance, fuming in the air; decomposed by water; made by treating a heated mixture of the oxide and carbon with chlorine.

Zirconium Fluoride. ZrFl4. Colorless, translucent crystals, made by heating a mixture of fluorspar and zircon in hydrochloric acid gas.

Zirconium Hydroxide. Zr(OH),. White, amorphous powder, precipitated from acid solutions of zirconium by ammonium hydroxide; decomposed by heat, yielding zirconium oxide.

Zirconium Oxide. ZrCy Zirconia. Amorphous powder, or quadratic prisms, obtained by igniting the metal or heating the hydroxide.

Zirconium Silicate. See Zircon.

Zirconium Sulphate. Zr(S04),. White mass, soluble in water, decomposing on heating; made by treating the hydroxide with sulphuric acid.

Zirknitz, Lake Of. In Carniola. Austria. In August, the water sometimes disappears long enough to raise a crop of hay on the bottom, being connected underground with the river Laibaoh. and the caves of Adelsberg. Length 6 m., breadth 3 m., depth 15-50 ft., alt. 1805 ft.

Z Iron. Bar whose cross-section resembles the letter Z, really like this [_; rolled of wrought-iron and steel, and used for making posts and compression members in bridges.

Zi*kn, John. 1360-1424. Bohemian officer, distinguished at Tannenberg 1410. and Agincourt 1415: leader of the Hussites from 1419; one-eyed, ami blind from 1421; victor in 13 battles and 100 skirmishes; only once defeated. At Deutsch-brod, Jan. 18,1422, he routed the Emperor Sigistuund, who had violated his safe-conduct and given Huss to the flames.

Zither. Musical instrument, extremely popular in the Tyrol and other mountainous sections of Germany and Austria. It consists of a flat sound-box strung- with from 36 to 42 strings, all but live of which are of gut or silk. The five areof metal, and

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Zither.

are extended over a finger-board fretted chromatically. Upon this board the tones are formed by the fingers of the left hand; the melody is plucked by means of a ring or plectrum fastened to the thumb of the right hand, while the harmony is supplied by the fingers, as in the case of a harp.

Zilluu. Town in s.e. Saxony, on a lignite deposit of 20 sq. in. It has manufactures of linen and cotton goods, dye and bleaching works, iron-smelting and glass works; also mineral springs. It was burned in the Austrian bombardment 1757. Pop., 1890, 25.400.

Ziltcl, Carl Alfred Von. b.1839. Prof. Munich 1866; author of an extensive handbook of Paleontology.

Zlittim. Town of Moravia: scene of a French victory July 11, 1809. An armistice was concluded the next day. Pop., 1890, 14,515.

Zoan, or Tanis. Former capital of Egypt under the Hyksos kings and in 19th dynasty; in the Delta; often mentioned in O. T.; destroyed 174. Its remains were explored by Petrie 1888-84.

Zoautharla (hexactinia). Division of Anthozoa, including coral polyps or polyp-stocks with tentacles in concentric circles and witli the mesenteric septa in multiples of six. This group includes the most common corals. The anatomy of the soft parts is similar to that in the Sea-Amsn&ne {Actinia).

There are three groups: Sclerobasica (Antipatliaria), Malacodermata (Actinaria), and Scleroderma!a (Madreporaria).

Zoanlhlda*. Family of Zoantharia, Malaeodermata. or Polyps, closely related to those that secrete coral, but free, having no hard, rock-like support; further characterized by including compound individuals, each consisting of many polyps united by a common coenosarc. The walls of these polyps are often strengthened by a crust containing grains of sand or spicules.

Zoar, or Bela. One of the Cities of the Plain, s.e. of Dead Sea; spared at Lot's prayer. Gen. xix. 20-23.

Zohah. Ancient kingdom of Syria, at war with Israel. Zockler, Otto, D.D., b.1838. Prof. Greifswald 1866; commentator. Cross of Christ, 1875. tr. 1877.

Zodiac. Zone of the celestial sphere, 16° in breadth, 8* each side of the ecliptic. It is divided into twelve signs of 30° each, beginning with the vernal equinox, as follows: Aries V Libra at

Taurus y Scorpio V\

Gemini LT Sagittarius /

Cancer 25 Capricorn us V?

Leo St Aquarius CS

Virgo "J> Pisces %

Originally these signs corresponded to the constellations having the same names, but by the action of precession the sign Aries now corresponds to the constellation Pisces nearly, and similarly with the others. Similarly designated signs are found among the ancient Egyptians. Arabs, Hindus, and Chinese, as also among the Aztecs and other primitive American tribes. See TROPICS.

Zodiacal Light. Faint beam of light extending aloDg the ecliptic on both sides of the sun; best seen in the evening

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Vernal Equinox.
The Zodiacal Light.

during Feb., March and April; supposed to be caused by the reflection of the sun's rays by meteoric matter in the vicinity of the sun.

Zoca. Earliest larval stage of the Lobster and Crab. (The nauplius and other early stages represented by free larvae in lower Crustacea are in Lobsters and Crabs passed through within the egg-shell.) It has a cephalotborax provided with three long spines, and a six-jointed abdomen without appendages. The only locomotor appendages present are those that represent the first two pairs of maxilipedes of the adult.

Zoecilim. 1. Chamber or cell in which the polypide of a Polyzoon is contained. 2. Equivalent of zooid.

Zocsu. Johann Georo. 1755-1809. Danish numismatist, antiquarian, and Orientalist, resident at Rome; cataloguer of Coptic MSS.

Zoepffcl, Richard Otto. D.D., 1843-1891. Prof. Strasburg 1872; ed., with H. J. Holtzmann, Lexikon fur Tlieologie. 1882-91.

Zoctrope. Optical toy in which a succession of figures in different attitudes are made to appear like a single one in motion. Two forms exist. In one the figures are arranged

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