cine bird, related to the wrens: it seeks its food on the bottom of swift brooks. Species of this genus occur in both hemispheres.

Oval. 1. Re-entrant curve having two foci, the distances from which to any point in the curve have a constant relation. The noteworthy ovals are the Cartesian and Cassian, each having several peculiar specific forms. 2. Figure formed by intersecting arcs of circles.

Ovalo AND Cavetto. Molding whose outline is the quadrant of a circle: when convex it is an ovalo, when concave a cavetto.

Ovampo. Bantu people of w. Africa, in the German territory, s. of the Cuanene.

Ovando, NICOLAS DE, 1460-1518. Governor of Hispaniola 1502-9. He refused shelter to Columbus in a storm, and nearly exterminated the natives.

Ovariotomy. Operation to remove an ovary. It is indicated when it is diseased (i.e. ovarian tumor) or when there is a reflex neurotic condition due to a hyper-sensitive condition without evidence of organic change in the organ. Ephraim M.Dowell, of Ky., first removed an ovarian tumor 1809. The removal of the ovaries and Fallopian tubes is now a frequent operation and is generally successful.

Ovary. Lowest portion of the pistil of flowers, containing the ovules.-Organ in animals which produces the eggs, or ova. In a woman there are two, 1 in. long, & in. wide, and in. thick, on either side of the uterus, to which they are connected by the Fallopian tubes, through which the ova pass to the uterus. At the time of menstruation the ova pass into the ovary by the rupture of the Graafian follicle in the cortical coating of the ovary, in which they mature. This coating is estimated to contain 30,000 ova. The ovaries are analogous to the testes of the male, and the ova are impregnated in the uterus. They are endowed with a generous nerve supply, and are frequently the cause of obscure nervous affections.

Ovate. Leaves or other organs which resemble in outline the longitudinal section of an egg, being broadest below the middle and not more than twice longer than wide, as in the Apple leaf.

Ovation. The Romans honored a victorious general either with the TRIUMPH (q. v.), or by the Ovation, wherein the general entered the city on foot, clad in a magisterial robe and wearing a myrtle crown. A sacrifice closed the ceremonies.

Oven. Chambers in which objects are baked by artificial heat. The early Egyptian oven was a crock sunk in the ground and heated by a fire built inside. The old type of baker's oven was a brick chamber, domed. Fire was made inside, and when the oven was sufficiently heated the ashes were raked out and the dough put in with a long wooden spade. Now most ovens are heated by fires built in a firespace, by superheated steam in pipes, or by gas. Loaves found in a Pompeiian bakery indicate that the name of the meal was stamped on bread.

Overbeck, FRIEDRICH, 1789-1869. German religious painter, important historically but weak as an artist, although dis

1

Overberg, BERNHARD, 1754-1826. German R.C. theolog Overburden. In Mining, superficial waste rock that to be removed in open workings.

English aut

Overbury, SIR THOMAS, 1581-1613. knighted 1608; imprisoned in the Tower, and poisoned th Characters, 1614.

Overhand. Operations in which the miner stands un the rock he is excavating.

Overland Route. 1. From Europe to Asia, via Egy before opening of Suez Canal, as opposed to the voyage arou Africa. 2. To California by the plains, prior to constructi of Pacific R.R., as against the voyage around Cape Horn.

members of a formation extend beyond the beds below, of t Overlap. In Geology, when the newer or more rect same series, the former are said to overlap the latter.

Overproduction. Excess of production in certain lin or production the ready distribution of which is prevented some imperfection in the organization of exchange. Overreaching. Said of a horse when he throws his hit foot against the heels or sole of the forefoot. Long hoofs large toe-calks on the fore feet will cause the trouble.

Overshot Water Wheel. Water wheel or motor i which a wheel of large diameter is mounted on a horizont axis, and the water is laid on without head at a point just b low the upper end of the vertical diameter in the direction i which the wheel is to turn. The water acts therefore by it weight alone to turn the wheel, since it comes to it withou shock. The buckets on the periphery of the wheel shoul

Overshot Water Wheel.

nearly fill with water, and should be of such a shape as not to be emptied too soon on the lower part of the arc. The length of the wheel varies with the amount of power required and water available; the diameter depends on the height of the fal of water. This type of wheel is cumbrous and costly, and slow moving. It has been largely replaced by the turbine wheels Its efficiency is from 70 to 90 per cent. One at Laxey, Eng land, is 72 ft. in diameter and furnishes ab. 150 H.P.

Overskou, THOMAS, 1798-1873. Author of Danish comedies and historian of the Danish Theater, 7 vols., 1854-76. Overstone, SAMUEL JONES LOYD, LORD, 1796-1883. M. P 1819, Baron 1850; writer on Bank of England.

Overt Act. Attempt to commit a crime. Overtones. So-called partial tones which accompany the fundamental tone in the complex sensation known as a clang. They are caused by the partial vibrations of the body whose complete vibration gives the fundamental tone. The number and variety of the overtones give the distinguishing quality or timbre to tones, voices, or musical instruments They include the harmonic overtones or harmonics, and may include certain tones which are inharmonic.

Overture. Opening musical piece of a drama, especially a lyric drama or opera. Originally it was vocal, and the first in strumental introductions were written in the vocal style. In its perfection it adopted the sonata form, and this was maintained in the overtures whose themes were borrowed from the operas which they introduced. The best of the overtures of Beethoven, Wagner and others seek to convey the emotional contents of the dramas with which they are associated.

Oxygenated Water. See HYDROGEN DIOXIDE. Oxyhemoglobin. HEMOGLOBIN (q.v.) containing a definite quantity of oxygen in loose combination, giving it a bright red color. It is found normally in the red blood-corpuscle and more abundantly in the arterial blood. The change of color, after the blood has gone through the capillaries and entered the veins, is due to some of the oxyhemoglobin giving up its oxygen in the tissue for the various bio-chemical processes and becoming hemoglobin, which again changes to oxyhemoglobin in the lungs. It requires an amount of oxygen equivalent to 1.76 c.c. at 0° C. and bar. 760 mm. to change one gm. of hemoglobin to oxyhemoglobin, and this proportion is constant. See CIRCULATION OF THE BLOOD, BLOOD, and RESPIRATION.

Oxyhydrogen Blowpipe. Apparatus for producing intense heat. The oxygen and hydrogen are led from two different sources to a jet consisting of a tube for the delivery of the oxygen, with a larger tube around it, the hydrogen being brought in through the annular space. Sometimes the gases are mixed in the body of the blowpipe. Invented by Dr. R. Hare in 1801. See DRUMMOND LIGHT. Oxyrhyncha (MAJACEA). See CRABS. Oxystomata. See CRABS.

Oxytricha. Genus of Hypotricha. It has cilia and bristles on the under side, by which it can walk over the surface of submerged objects, as plant stems.

Oxyuris. Pin-worm infesting the rectum of children. The females are larger than the males. See ASCARIDE.

Oyer. Hearing an instrument read on which an action was brought.-OYER AND TERMINER. Court of original jurisdiction over important crimes.

Oyster. See OSTREIDÆ.

Oyster-Catcher (HEMATO PUSPALLIATUS). Shore bird (see LIMICOLE) having short bright-colored legs, toes three-webbed at the base, a bill 3 in. long, and body 18 in. The upper parts are blackish, white beneath. It feeds on crustacea, not on oysters.

Oyster Culture. Artificial rearing of oysters for the market dates from the Roman period or even earlier, but only in America has it assumed vast proportions; 28,263,847 bushels, worth $16,152,257, being marketed in 1892, four

Dredging for Oysters.

sevenths from Maryland and Virginia. The natural bed where the oyster matures of itself is a bottom containing shells or gravel to which the young can attach themselves, and is so situated as to receive the washings of rivers at every low tide, bringing food (principally diatoms) into the sea, for the oysters.

These beds are public, and any one can take oysters from them: the consequence is that they are fast being destroyed. At present the oysters taken from them are too small for market, being less than a year old. They are seed, which the oysterplanter procures and places upon designated areas to fatten for market. Large market oysters are four or five years old, and have been in the planter's care three or four years. The discovery by Brooks of the bisexuality of our oysters, makes it possible to breed them as we do fishes. See PISCICULTURE. The attempt to raise oysters from the eggs dates from the experiments of Coste in France 1858, although earlier experiments were known. As the French oyster, Ostrea edulis, is hermaphroditic and viviparous, it is possible to get a catch of spat on submerged sticks, tiles, or shells, only by planting this cultch near spawning oysters. A similar method of catching oyster spat is practiced on a large scale in the waters of Long Island Sound, oyster shells being planted as cultch. This method is resorted to as fast as the natural seed beds are depleted. It has been successfully introduced into Virginia waters. The American oyster, O. virginiana, is dioecious and oviparous; the germs of both sexes being spawned into the water to shift for themselves, great loss of possible seed results, so that experiments have been made to utilize this spawn by more artificial methods (especially by Claire-culture). The experiments have been successful, but oystermen have not yet applied these methods on a commercial scale.

Oyster-Plant. See SALSIFY.

Oyster-Shell Bark-Louse (MYTILASPIS POMORUM). Insect parasite of apple and other fruit trees, introduced into America from Europe. It lives under an oyster-shaped scale, in. long, of same color as the bark. Eggs hatch in spring, when a wash of strong soapsuds or kerosene spray may be employed as a remedy.

Ozanam, ANTOINE FRÉDÉRIC, 1813-1853. French historical writer and critic; prof. Sorbonne 1841. Dante, 1839; Civilization in 5th Century, 1845, tr. 1868; German Studies, 1847-49.

Ozark Hills. Area of broken country, rising in places to ridges and hills of considerable height, in s. Mo., w. Ark., and s. Indian Territory; most important in Ark., where they consist mainly of abrupt e. and w. ridges of quartzite, 1,000 to 3,000 ft. high.

Ozena. Form of nasal catarrh accompanied by an offensive discharge. The disease is disagreeable to possess and difficult to cure. It is the form largely dwelt upon in the circulars and advertisements of the venders of nostrums for catarrh.

Ozerof, VLADISLAS ALEXANDROVICH, 1770-1816. Russian tragic dramatist. Edipus and Athene, 1804; Fingal, 1805; Dimitri Donskoi, 1807; Polyxena, 1809.

Ozokerite. Mineral wax; natural paraffin; substance consisting of carbon and hydrogen, and resembling wax or spermaceti in appearance, being nearly white when pure, but usually darkened by foreign matter. It was found in Moldavia 1833, in a bed of coal. Boryslaw, in Galicia, has been since 1859 the chief source of supply. Large deposits exist in Utah. It is widely used in the arts as a substitute for bee's-wax and in the manufacture of electrical insulators and candles.

Ozone. Allotropic form of oxygen, the molecule of which has the formula O.; discovered by Schönbein 1840; blue gas of characteristic odor, occurring in minute quantities in the atmosphere, especially during electrical storms; made by passing a series of electric sparks through an atmosphere of oxygen; much more active than oxygen; strongly irritating to the throat membranes. At 270° C. it is converted into oxygen. It condenses to a blue liquid at -106° C.

Ozone Tests. Chemically prepared paper which, upon being exposed to the air, is changed in its tint if any ozone is present. Thallium hydroxide is turned brown, and faintly acid litmus paper with potassium iodide is turned blue.

Ozonometry. Art of measuring the quantity of ozone in the atmosphere.

Paca, WILLIAM, 1740-1799. Delegate to Congress 1774-79; | signer of the Declaration of Independence; judge of Md. courts 1778-82; Gov. of Md. 1782-86; U. S. District Judge from 1789.

Pacchionian Bodies. Little bodies formed in connection with the middle membrane covering the brain (Arachnoid), which frequently contain chalky concretions that produce little depressions on the under side of the skull by their pressure.

Pace. See GAITS.

Pacheco y Osorio, RODRIGO, MARQUIS OF CERRALVO, d. ab.1650. Viceroy of Mexico 1624-35.

Pachomius, ab. 292-348. Egyptian monk, founder of the first monastery, on Tabenna in the Nile, ab. 340, and of the first nunnery. Before his time each monk was solitary. 7,000 of both sexes were under his care.

Pachuca. Mining town of Mexico, 56 m. n.e. of Mexico. Here Medina in 1557 discovered and used the patio process for the extraction of silver. The silver mines here were worked before the Spanish conquest. Pop., 1889, 32,800.

Pachydermata. See DIPLARTHRA.
Pachyglossa. See CRASSILINGUIA.

Pachymeres, GIORGIOS, 1242-ab.1310. Byzantine histo

rian.

Pacificator, THE. Name given to PAUL FERRY (q.v.). Pacific Ocean. Largest body of water on the globe, stretching from America to Asia and the E. India islands, a distance of 12,000 m., and from Bering Strait to the Antarctic Continent. Its area is ab. 67,500,000 sq. m., its mean depth ab. 2,500 fathoms, and maximum depth 5,000 fathoms. It contains vast numbers of small islands, some of which are volcanic in origin, others the work of coral polyps. It was first seen by Balboa at Darien 1513, and named by Magalhaes, who first sailed it 1520.

Pacific Railways. See RAILWAYS.

Pacini, GIOVANNI, 1796-1867. Italian composer of ab. 90 operas, popular only at home.

Pacinotti, ANTONIO, b. 1841. Italian electrician. The inventor 1860 of a dynamo-electric machine similar to that used later by Gramme.

Pacioli, LUCAS, d. 1510. Italian Franciscan, author of the earliest printed book on arithmetic and algebra. Summa Arithmetica Geometria proporzioni e proporzionalita, 1494.

Pacinian Corpuscles. Oval bodies about two mm. long in which a nerve fiber terminates. They are found in greatest abundance in those parts of the body where the sense of touch is most developed.

Packard, ALPHEUS SPRING, M.D., b. 1839. Prof. of Zoölogy and Geology in Brown Univ. 1878; most eminent as an entomologist; prolific writer.-His father, ALPHEUS SPRING, D.D., 1798-1884, was prof. Bowdoin Coll. from 1824, and its historian 1882.

Packer, ASA, 1806-1879. Builder and pres. Lehigh Valley Railroad; M.C. from Pa. 1853-57; founder of Lehigh Univ., to which he gave or bequeathed $2,500,000.

Packer, WILLIAM FISHER, 1807-1870. Gov. of Pa. 1858-61. Packing. In Mechanics, materials used to prevent leakage where a moving piece has different pressures on the two ends of its surfaces of contact. For packing of pistons and plungers see those titles. For rods and valve-stems some form of fibrous material made from cotton is usual, either by itself or in conjunction with rubber, which gives elasticity. This is pressed in upon the rod by conical surfaces (see STUFFING BOX), with just pressure enough to give it a fluid tight contact with the moving rod, and yet without excessive friction. Metallic packings are also much used, and, when well taken care of, work satisfactorily. They are usually alloys of the type of Babbitt metal, and get pressure from springs and conical contacts. Cotton lamp-wick, canvas and rubber, paper and asbestos fiber, are bases of numerous packings.

anthracite regions synonymously with the English term chock or nogs.

Pact. In Roman Law, agreement: if so made as to b legally obligatory, it was a contract; otherwise it was nude o naked. In English Law, a nude pact is an agreement withou a legal consideration.

Pactolus. Brook of Lydia, w. Asia Minor. Croesus wa supposed to have been enriched by the gold-dust which it bor down from Mt. Tmolus.

Pacuvius, MARCUS, ab. 220-130 B.C. Roman dramatist whose works were mostly adaptations from the Greek. Frag ments remain.

Paddock, ALGERNON SIDNEY, b. 1830. U. S. Senator from Nebraska 1875-81 and 1887-93.

Paddock, BENJAMIN HENRY, D.D., 1828-1893. P.E. Bp. o Mass. from 1873, and historian of the diocese 1885.-His brother JOHN ADAMS, D.D., 1825-1894, was P.E. Bp. of Olympia, Wash. from 1880.

Padella. Shallow vessel of metal or earthenware used in illuminations.

over.

Paderborn. Old town of Westphalia, 50 m. s.w. of Han It has a fine cathedral dating from 1163, and had a R. C university 1614-1819. The coinage of its bishops was extensiv ab.1600-1789. Pop., 1890, 17,986.

Paderewski, IGNACE JAN, b. 1860. Polish piano-fort virtuoso and composer; known in Europe since 1887. He mad concert tours in America in 1891-92, 1893, and 1895-96.

Padilla, JUAN DE, d. 1521. Gov. of Saragossa; leader o a revolt against governmental oppression; hero of Spanish legends and plays, with his wife, MARIA, d. 1531.

Padishah. Title of Turkish and Persian sovereigns. Padua. Ancient city of n. Italy, on the Brenta, 22 m. w of Venice; birthplace of Livy; subject to Rome from 215 B.C. twice sacked by Goths and Huns in 5th century; held by Venic 1405-1797, and then by Austria. Its university, founded 1221 has ab. 70 teachers, 1,400 students, and a library of 160,000 vols The city has many old and fine buildings: its palace was com pleted 1219. Pop., 1892, 79,500.

Paducah. Capital of McCracken co., Ky., on the Ohi and Tennessee rivers; scene of battle, March 25, 1864, between Union troops with gunboats and 6,000 Confederates under Gen Forrest. Pop., 1890, 13,076.

Pæan. Joyful or triumphant song, originally a hymn t Apollo.

Pædobaptists. Those who practice infant baptism; i.e. the vast majority of Christians. 1117