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at the crossing or intersection of the nave and transepts of a Gothic church.

Roof. In Mining, rock overlying a seam of coal or any nearly horizontal ore deposit; corresponding to the hangingwall of veins or the more highly inclined deposits.

It oof*. The largest roof ever constructed was that over the Manufactures and Liberal Arts building at the World's Columbian Exposition of 1893 in Chicago. Its total width was 787 ft., supported by three trusses, and its length 1,687 ft., the total area being 3<H acres. The central court was covered with arches 210 ft. high and 368 ft. in span, and the entire floor area, including galleries, nearly 40 acres. The train shed of the Pa. R.R. at Philadelphia has a roof 304 ft. span and 598 ft. long, while that at Jersey City is 256 ft. span and 653 ft. long.

Roof Truss. Truss, containing tensile and compressive members, for supporting the roof covering of a building. See Roofs.'

Rookc, Sir George, R.N.. 1650-1709. Rear-admiral 1689; knighted and pensioned for a battle with the French off Cape La Hogue 1692; prominent in war with Spain 1702 and the taking of Gibraltar 1704; engaged in a severe but indecisive battle«with a French fleet off Malaga Aug. 1704; retired 1705.

Room. Portion of a coal mine in which the actual work of getting the coal is carried on; a breast or stall.

Roon, Albrecht Theodor Emil. Graf Von, 18031879. Prussian Minister of War 1859-72 and of Marine 1861-71; reorganizer of the army; Count 1871, Field-marshal 1873.

Roosevelt, Robert Barnwell, b. 1829. N. Y. Fishery Commissioner 1867; M.C. 1871-73; Minister to the Netherlands 1888-89: author of Game Fishes, 1860; Game Birds, 1866; Florida, 1868.—His nephew, Theodore, b. 1859, U. S. Civil Service Commissioner 1889, Asst. Sec. Navy 1897, has pub. Hunting Trips, 1883; War of 1812, 1885; Life of Benton, 1887; Ranch Life, 1888; Winning of the West, 4 vols., 1889-95; Hist. New York City, 1891; Tlie Wilderness Hunter, 1893.

Root. Descending axis of a plant. It is the organ which is most efficient in the absorption of water. It is generally entirely subterranean, but portions, or all of it, may be aerial. See Secondary Roots, Aerial Roots, Epiphytes and ParaSites.

Root. In Philolosry, essential and primitive part of a word; monosyllabic, uninflected. without modifications of any sort, expressing the general idea at the basis of the word. It is the germ or nucleus of all later formations.

Root Of An Equation. Value which, substituted for the unknown quantity, satisfies the equation.

Root Of A Quantity. One of its equal factors. The index of the root shows how many such factors enter into the

quantity. A root is indicated by the radical sign «/. Having

the index of the root to the left and slightly above, as

-^a, indicates the cube root of a; or by a fractional exponent

having the index as the denominator, as a.^, indicates the cube root of a. Roots are real or imaginary. Even roots of a negative quantity are imaginary: as two or any even number of negative factors give a positive product, there is no real factor, which, repeated an even number of times, will give a negative quantity. Any quantity has as many roots, real or imaginary, as the order of the root.

Root, George Frederick. Mus.Doc, 1820-1895. American composer of many popular songs.

Root, Jesse, 1736-1822. Delegate to Congress 1778-83; ■Chief-justice of Conn. 1796-1807. Reports, 1789-1802.

Root, Oren, D.D., L.H.D., b. 1838. Prof. Univ. Mo. 186671; pres. Pritchett Coll. 1871-80; Prof, of Mathematics. Hamilton Coll.. 1881.—His brother, Elihu, b. 1845, was U. S. Dist.atty. in New York 1883-85.

Root and Rranch Men. Opponents of Episcopacy in House of Commons 1641.

Root-Cap. Tip of an advancing subterranean root, composed of empty cells, pushed ahead by the formation of new ones immediately behind.

Root-Hairs. Cellular prolongations from the epidermis of roots. They form a very large portion of the absorbing surface.

Rootlets. Small roots, especially when the roots are numerous and all small.

Root Parasites. Plants which grow upon and derive their nourishment from the roots of other plants. Such are species of Thesium, the Rafflesias, and the broom rape or strangle weed, Orobanche minor, which develops upon the roots of many plants, especially that of clover in its second year.

Rootstock. See Rhizome.

Ropes. Ropes are made of manilla, of hemp, and of iron or steel with a hemp center. A hemp rope 1 in. in diameter has an ultimate strength of ab. 15,000 lbs., while one of wrought iron has 125,000 lbs. (see Wire Rope). Yams are spun righthanded. Several yarns, formed into a strand or "ready," make it lefthanded. Three strands laid up righthanded are called plain-laid or hawser-laid rope: four strands around a central core or heart of ab. i size of the strands are called shroud-laid; cable-laid is a left-handed rope of nine strands, each three being laid up in a group. Hemp makes the best ropes. To find strength of hemp rope in pounds, multiply the square of circumference in inches by 1371.4; or the breaking weight in tons — square of half the circumference, circumference measure.

Ropes, John Codman. b. 1836. tary history.

Roqne, St., d. 1327. Patron of plague patients.

Roquefort. Village of s.e. France, 44 m. n. by w. of

Beziers; noted for its white cheeses.

Roqueplan, Joseph Etienne Camille, 1802-1855. French genre and landscape painter.

Roratma. Isolated mountain in British Guiana on the Venezuelan frontier, rising on an immense parallelogram, 1,3001,600 ft. high, with walls cut to the summit. Altitude 8,600 ft.

Rorke's Drift. In S. Africa, on the Tugela; defended by 80 British soldiers against 4,000 Zulus Jan. 22-23, 1879.

Rorquals. Whales with short, broad baleen plates, including Humpbacks, Finbacks, the California Gray Whale (30 to 70 ft. long), and the Sulphur Bottom or Razorback, the largest of living animals, ranging in length from 60 to 100 ft.

Rosa, Carl, 1842-1889. German violinist and manager, producer of English operas. See Parepa-rosa.

Rosa, Pietro, ab. 1815-1891. Italian archaeologist and Senator, who did much for the study of Roman antiquities.

Rosa, Salvator, 1615-1673. Most romantic and inspired painter of the School of Naples; best in battle scenes and land

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Strangle Weed. Ropes are known by their

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broad rounded petals on very short e'awe; also tiowers similar to roses. Rosantline. See Fuchsine.

Rosa of Lima (isabel Flores), 1586-1617. Peruvian nun, canonized 1671.

Rosarlo. City of the Argentine Republic, on the w. bank of the Parana: founded 1725. It has a large trade in grain, cattle, wool and hides, which it exports direct to Europe. Its growth and importance are of the last half century. Pop. ab. 75,000.

Rosary. 1. String of beads on which prayers are counted; used by Christians, Mohammedans, Buddhists, and Brahmins. The Mohammedan rosary has 100 beads; that universally employed by the Buddhists, as well as the Brahminical rosary used in Vishnu and Krishna worship, have 108. The rosary is clearly an inheritance from primitive conditions, and its original significance was cosmical, the beads referring to the various divisions of the terrestrial and celestial circuits. In R.C. Ch., the string usually has 5 beads for Paters and 50 for Aves, to keep tally of prayers repeated: it was probably brought to Europe from the East by Crusaders. 2. Set of R.C. prayers, each including 5 Paters, 5 Glorias, 50 Aves, and 5 Meditations. This is the lesser rosary, 3 of which constitute the greater.

Rosas, Juan Manuel De. 1793-1877. Dictator of Buenos Ayres 1835-52, ruling by fear and blood; invader of Uruguay 1839 and later; attacked by England and France 1845: overthrown by a coalition with Brazil; in England from 1852; denounced by Argentine Congress 1861 as a murderer and robber.

Rosazurlne B. Cj.H.oN.O.S.Na,. Sodium salt of the compound, formed by the action of the diazo compound of tolidine on a methyl-/i-naphtholsiilphonir acid. It dyes cotton red without mordant, and is a brown powder. Other similar rosazurines are known.

Rosbeke. Village of Flanders, where Philip van Artevelde with 20.000 Flemings was defeated and slain by the French Nov. 27, 1382.

Roscelin, or RUCELINUS, ab.1050-ab.1122. French priest. Canon of Compiegne, condemned at Soissons 1092 for tritheism; teacher of Abelard, with whom he had a violent controversy; supposed founder of Nominalism.

Rosclier, Wilhelm Georo Friedrich, Ph.D., 1817-1894. Prof. Gottingen 1843. and Leipzig from 1848; prolific writer on political economy, of the historical school. System der Volkswirthschaft, 1854-88; Qeschichte der Nationaliikonomie in Deutschland, 1874.

Rosclus, QuiNTUS, d. 62 B.C. Greatest of Roman actors; most eminent in comedy.

Roscoe, William, 1753-1831. Ensrlish biographer of Lorenzo di Medici 1796, and Leo X. 1805. Poems. 1857.—His grandson. Sir Henry Enfield. LL.D.. D.C.L., F.R.S., b. 1833, Prof, of Chemistry at Owens Coll., Manchester. 1858-86, M.P. 1885, was knighted 1884. Spectrum Analysis, 1868; Elementary Chemistry, 1870.

Roscoclite. Rare mineral, resembling small scales of brown or greenish-brown mica, and containing an unusually large percentage of vanadium. It has been found in smail quantity associated with gold in California.

Roscommon, Wentworth Dillon, Earl Of, ab.16331684. Irish poet. Essay on Translated Verse, 1660; tr. Horace's Art of Poetry, 1684.

Rose. Showy-flowered, prickly shrubs of the genus Rosa,

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Their characteristics are shrubby growth, prickly stems, terminal flowers and leaves alternate. In color they are white, pink, yellow or red.

Rose, Ernestine Louise Lasmond (potowski). 1810-1892. Polish-American reformer, active for Woman's rights.

Rose, Gustav, 1798-1873. German mineralogist, widely known for his researches on the relations between crystalline form and physical properties. His Mineral System, 1852, is based on crystallographic and chemical principles. Elemente der Krystallographie, 1833. The science of Petrography originated with him. and he was the first to teach the method of studying rocks by means of their microscopic sections.—His brother, Heinrich, 1795-1864, prof. Berlin from 1822, was eminent as an analytical chemist. Handbuch, 1829.

Rose, Huoh James, 1795-1838. Prof. Durham 1833; pres. King's Coll., London, 1836; ed. Encyc. Metropolitana. 1836; active in the Tractarian movement, though a Cambridge man.

Rose, Sir John. b. 1820. Canadian official, in England since 1869; knighted 1870.

Rose, Thomas Ellwood. b. 1830. Col. U. S. Vols. 1863; organizer of a famous escape from Libby prison, Richmond, Feb. 1864.

Rose-Acacia. Robinia hispida. Bristly-stemmed shrub of the natural family Leguminosai, bearing showy, rose-colored flowers, native of the s. Alleganies; much planted for ornament; called also Bristly Locust.

Roseala. Bright, usually dark-red rash accompanied with little or no fever. It occurs usually in children and is sometimes mistaken for scarlet fever or measles. The absence of the throat symptoms distinguish it from the former and of the cold in the head from the latter. The eruption lasts for a fendays, is never severe, and hardly needs any treatment.

Rose Apple. Eugenia jambos. Small tree of the Myrtle family, native of the E. Indies, and cultivated in tropical countries for its ornamental flowers and fruit.

Rose-Bay. See Rhododendron and Oleander.

Rose Bengal. C^h.cijlojk,. Potassium salt of tetraiododichlorfluorescein, made by the action of iodine on dichlorfluorescein; brown powder, easily soluble in water. It dyes wool red in an acid bath.

Roscbcry, Archibald Philip Primrose, LL.D.. Earl Of, b. 1847. Fifth EarJ 1868; Foreign Sec. 1886 and 1892; Premier 1894.

Rosebug, or Rose-chafer. Beetle, f in. long, yellowish brown. It feeds on leaves, fruit, and flowers, preferring the rose. They appear on grapes about the time Concords are in bloom, and may be checked by spraying with water at 130° F., or whaleoil soap; or they can be collected by knocking off into sheets and killing with kerosene.

Rosccrans, William Starke, U.S.A., b. 1819. Prof, at West Point 1843

47; Brig.-gen. 1861. Major- _ ,. , , „ ,

IT O V„l. 1HAO £T« Rosebug, or Rose-chafer (Cetonia aurata), gen. U. 8. Vols. 186^. He larva and cocoou.

commanded the army of

the Mississippi 1862, winning the battles of Iuka and Corinth, and that of the Cumberland, defeating Bragg at Murfreesboro Jan. 2, 1863. but beaten at Chickamauga Sept. 19-20. In 1864 he drove Price from Mo. He resigned from the armv 1867; was Minister to Mexico 1868-«9: M.C. from Cal. 1881-85,"and Register U. S. Treasury 1885-93.

Rose Call. Gall produced on roses by an insect. See Gallicola.

Roscgger, Petri Kettenfeier, b. 1843. Austrian novelist and poet, dealing with humble life in Styria.

Roselne. Usually rosaniline acetate; sometimes FuchSine (q.v.).

Roselius, Christian, 1803-1873. Head of La bar; Prof. Civil Law in Univ. La. from 1850.

Roselli, Cosimo. 1439-1507. Florentine painter. He has frescoes in the Sistine Chapel at Rome.

Roscllini, Ippolito. 1800-1843. Prof. Pisa 1824; in Egypt with Champollion 1827-28. Monuments of Egypt and Aubia, 12 vols., 1832-44.

Roselly de Lorgues, b. 1805. French author. ChrM before the Age. 1835; The Cross, 1844; Columbus, 1856-85.

Rosemary. Rosmarinus officinalis. Shrub of the Mint family, native of s. Europe; cultivated for its essential oil. used in perfumery; anciently used as a love charm, and regarded as an emblem of remembrance.

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Rosen, Friedrich August, Ph.D., 1805-1837. Prof Univ. London 1829. Radices Sanscritce, 1827; ed. Veritas, 1836-38.

Rosendale Cement. Natural hydraulic cement, manufactured out of limestone from the Rosendale quarries near Rondout. N. Y.; also often any natural hydraulic cement. It is quicker setting but not as strong as the artificial Portland cement. See Cement and Cement Tests.

Roienkranz, Johann Karl Friedrich. Ph.D., 1805-1879. Prof. Halle 1831, and Konigsberg from 1833; historian of poetry and philosophy. Hegel, 1844-70; Pedagogics, 1848, tr. 1886.

Roscnmuller, Johann Georg, 1736-1815. Prof. Erlangen 1773. Giessen 1783, Leipzig 1785; voluminous theologian. Scholia in N.T.. 10 vols., 1777-90.—His son. Ernst Friedrich Karl, 1768-1835, Prof. Leipzig 1796, pub. Scholia in V.T., 16 vols., 1788-1817, and Analecta Arabica, 1824-27.

RosenmUllcr's Organ. See Epo-ophoron.

Rose-Noble. English gold coin, minted ab. 1340-1420: value ab. $1.65.

Rosenthal, Isidor, b. 1836. Prof. Erlangen 1867; writer on physiology and biology.

Rosenthal, Moritz. b. 1833. Prof. Vienna 1875; writer on the nerves.

Rose of Jericho. See Resurrection Plant and Althaea.

Rose of Sharon. Hibiscus syriacus. Ornamental malvaceous plant. The one mentioned in the Bible was probably a kind of narcissus. See Resurrection Plant.

Roseroot. Sednm roseum. Fleshy herb of the natural family Crassidacea. growing in rocky places in the colder and Alpine regions of the n. hemisphere.

Roses, War Of The. 1455-85, between princes of the houses of York and Lancaster, each claiming the throne by descent from Edward III. The York rose was white; that of Lancaster red.

Rose's Metal. Easily fusible alloy consisting of lead 1, tin 1, and bismuth 2. It expands up to 44° C, then contracts up to 69° C when it has less volume than at 0° C, and then expands up to its mpt. 94° C.

Rose Quartz. Pink or pale red variety of quartz, transparent, and crystalline in structure. The color is supposed to be due to the presence of manganese. The mineral is commonly too easily cracked to be of use as an ornament.

Rosetta. Town of Egypt, near the Nile's mouth; taken by the French 1798; by the British and Turks April 19. 1801. The R. stone, discovered here 1799, received much attention, and was important in the study of hieroglyphics. It contains a tritingual inscription (hieroglyphic, demotic, and Greek) by means of which, aided also by a bitingual inscription on an obelisk, Champollion in 1822 obtained clews leading to the decipherment of the hieroglyphic writings. It is now in the British Museum.

Rosette. 1. Ambulacra] areas of the dorsal surface of echinoids. 2. In Sponges, spicule consisting of several equal axes, each of which is terminated by trichites.

Rosette. In Botany, tuft of leaves arranged something like the petals of a doubled rose.

Rosetti, Constantin, 1816-1885. Roumanian poet, journalist, deputy, official, and senator.

Rose Water. Product obtained when rose petals and water are distilled. Sometimes oil of roses is used instead of petals.

Rose Window, or Wheel Window. In Gothic Architecture, a circular opening decorated with tracery, sometimes composed of circles and segments of circles, and sometimes arranged with reference to base radiating from the center like the spokes of a wheel.

Rosewood. Timber of numerous trees of tropical regions. The best is considered to be obtained from species of Dalbergia, natural family Leguminosoz, natives of tropical America.

Rosherville Gardens. Pleasure resort near Gravesend, Eng., formed by Mr. Rosher in old chalk-quarries.

Rosicrucians. Mystification, describing the disciples of the Rosy Cross as a wonderful society of semi-magicians and healers;"set afloat probably by J. V. Andrea 1614. The pamphlet, Fama Fraternitatis, made a great sensation and led to much controversy. This and other works, 1615-16. professed to describe a society founded 200 years before by Christian Rosenkreutz, who had acquired the wisdom of the East by travel in Arabia and Egvpt. Besides its medical secrets, it possessed the art of making gold.

Rosin. See Colophonium.

Rosin Riblc. Name given to the Douay Bible, from Jeremiah viii. 22. See DOUAY VERSION.

Rosini, Giovanni. 1776-1855. Italian critic, poet, and writer of historical romances.

Rosin Plant. Coarse yellow-flowered herbs of the genus Silphium. of the Composite family, with an abundant resinous juice, natives of N. America.

Rosmini, Antonio, 1797-1855. Tyrolese priest, founder of an Institute of Brethren of Charity, 1830, for clerical education; philosophic writer of high grade, much calumniated and greatly honored. Origin of Ideas, 4 vols., 1830, tr. 1883-84; Philosophic System, 1845, tr. 1882; Psychology, 1846-48, tr. 1884-88; Theosophy, 5 vols., 1859-74.

Rosny, Leon De, b. 1837. Prof. Paris 1868; writer on Chinese and Japanese philology and antiquities. Rosolan. See Mauve.

Rosolic Acid. CJ0H,,O,. Methylaurine. The pure acid can be made from rosaniline by diazotizing it. Commercially, it is not to be distinguished from AURINE (q.v.), in which it is present. It is used as an indicator in volumetric analysis. See CORALLIN.

Ross, Alexander. 1699-1784. Scottish poet. Helenore, 1768.

Ross, Alexander Milton, b. 1832. Canadian naturalist.

Ross, Edmund Gibson, b. 1826. U. S. Senator from Kansas 1866-71; Gov. of New Mexico 1885.

Ross, George, 1730-1779. Delegate to Congress from Pa. 1774-77; signer of the Declaration of Independence.

Ross, James. 1762-1847. Pa. Federalist, prominent in suppressing the whisky rebellion of 1794; U. S. Senator 1794-1803.

Ross, Sir John. R.N., 1777-1856. Scottish Arctic explorer 1818 and 1829-33; knighted 1834; Rear-admiral 1851, after an expedition in search of Sir John Franklin Voyage of Discov

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ery, 1819; Navigation by Steam, 1828; Narrative, 1835.—His nephew, Sir James Clark. R.N., F.R.S., 1800-1862, bore part in several Arctic voyages, discovered the north magnetic pole 1831. conducted a magnetic survey of the British isles 1835-38, explored the Antarctic seas 1839-43, was knighted 1844, and went in search of Franklin 1848. Narrative, 1847.

Ross, John, ab.1790-1866. Cherokee chief, leader in opposing the removal of his tribe from Ga. 1835.

Ross, Sir John, b. 1829. English general, prominent in the Afghan war 1878-80; knighted 1880; Lieut.-gen. 1886; commanding in Canada 1888.

Ross, Ludwig, 1806-1859. Prof. Halle 1845; student of Greek archaeology.

Ross, Robert, 1770-1814. British officer, who won an action at Bladensburg, Md., Aug. 24, 1814, burned Washington, and was killed near Baltimore.

Ross, Sir William Charles, R.A., 1794-1860. English painter, chiefly of miniatures, knighted 1842.

Rossall College. Public school founded 1844 on the coast of Lancashire, 2j m. s.w. of Fleetwood, Eng. It has ab. 30 professors and ab. 400 students.

Rossbach. Village of Prussian Saxony. 22 m. w. by s. of Leipzig; scene of a rout of French and Austrians, Nov. 5, 1757, by Frederic II.

Rossbrunn. Village of Bavaria, scene of a Prussian victory July 26. 1866.

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Rosse, William Parsons, 3d Earl Of, 1800-1867. M.P. 1821; Earl 1841; Peer for Ireland 1845; pres. Royal Society 1848-54; noted for his scientific researches, especially in Optics and Astronomy. In 1842 he constructed his great reflecting telescope of 6 ft. aperture, which is mounted at his observatory, Parsonstown, Ireland.

Ro§gel, Elizabeth Paul Edouard De, 1765-1829. French Rear-admiral 1822; editor of several books of voyages and discoveries.

Rosselll, Cosmo. See Roselli.

Rosselllni, Bernardo, 1409-1464. Florentine sculptor and architect, restorer of man}' churches.

Rosser, Thomas Lafayette, b. 1836. Brig.-gen. C.S.A. 1863; Major-gen. 1864; prominent as a cavalry commander in Va.; chief engineer Canadian Pacific R.R. 1881-82.

Rossettl, Christina, 1830-1894. English poet, eminent for delicacy of style and depth of feeling; daughter of Gabriele. Goblin Market, 1862; Prince's Progress, 1866; Singsong, 1872; A Pageant, 1881. In prose. Stories, 1870; Speaking Likenesses, 1874; Letter and Spirit, 1883. Her poems, collected l!-90, are mainly lyrical and often devotional.

Rossettl, Gabriel Charles Dante, called Dante Gabriel. 1828-1882. Son of Gabriele; English poet and painter; one of the founders of the preraphaelite school; a mystic and transcendentalist, whose pictures have a markedly individual stamp and character, but are not wholly free from affectation and self-consciousness. Asa poet he ranks best. The Blessed Damozel is his most noted lyric. Letters, 1896.

Rossettl, Gabriele, 1783-1854. Italian poet and patriot, proscribed 1821; prof. King's Coll., London, 1827. Dante, 1826; Anti-papal Spirit, 1832.—His oldest child, Maria Francesca, 1827-1876, pub. A Shadow of Dante.—His second son, William Michael, b. 1829, tr. Dante's Hell, 1865, ed. Shelley, 1869, and other poets, and pub. Fine Art, 1867, and Life of Keats, 1887.

RoNfti. Ernesto, 1829-1896. Italian actor, noted in Shakespearian parts: in the U. S. 1881.

Rossi, Francesco De, 1510-1563. Italian painter.

Rossi, Giovanni, 1754-1827. Italian writer of fables, comedies, and art studies.

Rossi, Giovanni Battista, 1822-1894. Italian archaeologist, noted for researches in the Catacombs. Inscriptions, 1861•s8; Stibterranean Christian Rome, 1864-77.

Rossi, Pelleqrino, 1787-1848. Prof, at Bologna 1812, Geneva 1815, and Paris 1833; French envoy to Rome 1845. Penal Law, 1830; Constitutional Law, 1836; Political Economy, 1840.

Rossini, Gioacchino Antonio, 1792-1868. Italian operatic composer, in whose works the characteristics of the national style reached their climax. He produced his first opera 1810 and his last 1829. After the last date he lived chiefly in Paris, composing only a few trifles and the famous Stabat Mater,

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Host, REINHOLD, 1822-1896. German-English Orientalist. Rostellate. Diminutive of rostrate.

Rostcllum. Conical projection, armed with hooks, on the head of Cestodes, as in the Tapeworm.—In Orchidology, projection from the column of the flower which bears the pollen-masses.

Roster. 1. Army list. 2. List of classes and studies in a college or school.

Rostock. City and river-port of Mecklenburg-Schwerin, on the Warnow, 9 m. from the Baltic; old Hanse town. Its small coinage is abundant ab.1600-1865. Its university, founded 1418, rebuilt 1867, has 40 instructors, ab. 420 students, and a library of 140,000 vols. Pop., 1890, 44,388.

Rostofr. 1. Town of s. Russia, on the Don, near its mouth; founded 1761; important for commerce and manufactures. Pop. ab. 70.000. 2. Town of central Russia, 129 m. n.n.e. of Moscow; noted for its annual fair. Pop. ab. 17,000.

Rostopcliin, Fedor Vasiliwich, Count. 1763-1826. Russian general, Gov. of Moscow 1812. He denied the burning of the city, except his own house. Works, 1853.

Rostra. Name of the pulpit or orator's seat in the Roman Forum, which was decorated with the prows of vessels takeD from the enemy.

Rostrate. In Botany and Zoology, organ extended into a slender prolongation or beak.

Rostrum. 1. Beak or sucking organ of certain insects. 2. Anterior prolongation of the carapace of Lobsters. Rosulate. In Botany, organs arranged in a rosette. Rosy Cross. See Rosicrucians. Rot. See Sheep Rot.

Rotalidea. Order of perforate Foraminifera, with calcareous shells spirally coiled in such a way that all the turns are discovered upon one side and only the last turn upon the under side, where the terminal aperture is situated.

Rotary Engine. Steam engine in which it is sought to produce continuous rotation of the driving-shaft by the action of steam upon pistons borne at the end of a revolving crank in the cylinder. The steam enters at one point, acts upon the

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Rotary hJiglne.

pistons by means of its pressure, and escapes at the opposite side, being obliged by the presence of an abutment (see Rotary Pump) to press so as to turn the shaft always in one direction, and to be prevented from passing from inlet to exhaust without doing work. The advantages of the rotary type of engine are direct application of the power on the shaft, compactness and portability, easy reversibility even from a distance, with no dead centers: all parts are inclosed within the casing, and not affected by weather or by missiles in quarry and similar work. The disadvantages are unequal wear of packing of pistons and consequent leakage, due to the different paths described by different points; excessive clearance and wasterroom in the cylinder; the difficulty in attaining expansive working of the steam, and hence their extravagant use of steam; the difficulty in securing piston-area for large sizes, or, if area is obtained, adequate piston-speed. Expansive working of steam has been secured by compounding several engines on

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