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the Catholic and Lutheran Churches, that Christ is corporeally, or at least spiritually, present in the elements consecrated and administered in Holy Communion.

Real Quantity. One involving in its combination no impossible operations.

Real Wages. See Nominal Wages.

Reamer. Steel tool for enlarging a hole that has been made. Taper reamers have this as their primary function, and are much used in riveted work, where the hole is made intentionally too small, so that the metal fatigued by punching may be reamed away (see PUNCH). Also where holes in a riveted seam do not come opposite, but are ''half-blind," a taper reamer enlarges both holes till the rivet will pass through. The reamer also appears as a cylindrical bar into which flutes have been milled, so that the tool, when introduced into an untrue hole, will cut it cylindrical, straight, and of exact diameter to gauge. Standard tapers for assembling work are also produced by the use of similar reamers of exact taper and size.

Reaper. Machine used for harvesting grain. It delivers the grain in loose bundles or gavels at the side of the machine.

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It was the forerunner of the binder, which has now superseded it, except on small farms in the rougher portions of the country, where but little grain is raised.

Reason. In its most general sense, conscious intelligence, which is able to adapt means to a given end; also loosely used in many other senses, but most particularly to designate that logical faculty by which the mind arrives at a judgment by any process of inference from previous judgments. In a simple process of reasoning the main steps are assimilation and association; e.g., I see the flame of a candle, and believe that if I place my finger in the flame it will be burned. If I perform this process with conscious reflection, the steps are these: I first recognize and identify, i.e., assimilate, the presentation of the flame; I next associate it with previous experiences of other similar flames accompanied by painful sensations of heat under certain circumstances, and from these premises draw the conclusion that the flame in question will produce a similar sensation under similar conditions; viz., a sufficiently close approximation of the flame and finger. The process is even in its simple form a complex one, involving recollection and discrimination, but the chief factors are assimilation and association.

Reaumur, Rene Antoine Ferchauj,t De, 1683-1757. French physicist, pensioned 1722; discoverer of methods of making steel and opaque glass; inventor of the thermometer named from him, of which zero is the freezing point of water ami 80° is the boiling point of alcohol. Hist, des Insectes. 6 vols., 1734-42.

Reaumur'* Poreelain. Opaque glass, devitrifled by sudden heating and cooling, invented by R. 1739. It is tougher and less fragile than ordinary glass.

Rebecca Riots. Series of outbreaks in England 1843-44. due to the indignation of the people at the great increase of toll-gates on the public highways. Men in female attire tore <lown the toll-bars by night. Their motto was from Gen. xxiv. 60.

Rebeknll. In Genesis, daughter of Bethuel. greatniece of Abraham, wife of Isaac, and mother of Jacob and Esau.

Rebellion. Rising, not permanently successful, against a government; as that of the Parliament against Charles I., 1642, the results of which were overthrown 1660 by the reeetablishment of the Stuarts. Lasting success, as in England 1688-89, and in America 1775-83. converts rebellion into revolution.

Rebolledo. Bernardino, Count De, 1597-1676. Spanish poet and official, Envoy to Denmark and Sweden. He versified Job and the Psalms.

Rebut). Puzzle in which words or phrases are represented by pictures of objects, the names of which are simHar in sound to the syllables or words intended. The picture-writing of the Aztecs was of this character, they not having advanced to the alphabetic stage.

Reeauiler, Jeanne Francoise Juije Adelaide (bernard), Mme., 1777-1849. French beauty of high character, head of a famous salon; exiled 1811-14; friend of Mme. de Stael and Chateaubriand.

Reeaption. Remedy, which the common law allows one to enforce, of retaking, without legal process, goods, wife, child, or servant wrongfully taken and withheld. Statutes and modern judicial decisions have limited its exercise.

Reeapture. In International Law, taking of a captured vessel by one of the same state or of an ally. It entitles the recaptor to salvage.

Receipt. Taking possession of a thing, or written acknowledgment of such taking. It is not a contract, and may be explained b3- parol evidence.

Receiver. Court appointee whose duty is to take and hold the property of another, in the interest of all parties interested therein. The power of appointment is generally defined bv modern statutes: the exercise of the power in each case is largely a matter of judicial discretion. Receiver's certificates are non-negotiable instruments for the payment of money, issued by receivers under the order of a court.

Receiver, Telephone. Instrument employed on telephone lines to receive the electric currents and deliver their energy to the air in the form of sound waves. A convenient form is that invented by Bell, consisting of a straight steel magnet upon one pole of which is a bobbin of fine insulated copper wire. In front of and very near to this pole is a thin

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circular iron diaphragm, capable of vibrating to and fro, following the fluctuations in the strength of the magnet caused by the varying current which passes round the bobbin. Thus sound waves are started in the air by the vibrations of the plate.

Air-pump.—Bell-slass in connection with an air-pump from which the air may be exhausted. Its lower edge is ground flat, and it rests on a flat metal or ground glass plate. See Air


Receptacle. In Botany, end of the peduncle. See Torus.

Rcchabltes. 1. Tribe or family of Midianite origin, at Jerusalem ab. 600 B.C.: they lived in tents and used no wine. Jer. xxxv. 2-19. 2. Order of total abstainers in England and the U. S.

Recife. See Pernambuco.

Reciprocal Of A Quantity. Unity divided by the quantity. It is indicated either in fractional form or by placing a minus sign before its exponent.

Reciprocal Equation. One in which the substitution of the reciprocal of the variable for the variable will not alter

the equation. If a be a root, then will - be also a root.

Reciprocally Proportional. Quality of variables

1 when their product is constant.

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Reciprocal Rectangles. Those equivalent and Dot equal; so called since altitudes are proportional to reciprocals of bases.

Reciprocity. Treaty relation between states, by which each is bound to accord to the other certain privileges, chiefly commercial, in return for like benefits.

Reciprocity, Principle Of. Idea assumed to unite the interests of the individual with the good of society, his good actions gaining hini esteem and advantages, and benefiting society by leading others to imitate his example.

Reciprocity Treaty. Between U. S. and Canada; concluded June 5 and ratified Sept. 9, 1854; abrogated 1806, on notice given by U. S. 1865.

Recitative. Kind of music used in opera, oratorio, and cantata, between plain speech and melody, and connecting the set or more highly organized forms of the work. In its simplest form it foregoes the raised rhythms used in artificially constructed pieces, and depends chiefly on variety of pitch: its most useful purpose is to hasten the action. When accompanied simply by an occasional chord on double bass and violoncello or pianoforte, it is called recitativo seeco or dry recitative; when treated more melodiously and accompanied by the orchestra, it is recitativo stromentato or accompanied recitative. It came in with the invention of the opera.

Recke, Ernst Von Der, b. 1848. Danish dramatist, poet, and critic.

Recklinghausen, Friedrich Daniel Von. b. 1833. Prof. Wurzburg 1866, and Strassburg 1872; writer on pathology.

Rcclinate, or Inflexed. Method of vernation where the upper part of a leaf is bent on the lower, as in the Tuliptree.

ReelIik, Jean Jacques Elisee, b. 1830. French geographer and communist, banished 1871-79. T)ie Earth, 1887, tr. 1871; Geographic Universelle, 19 vols., 1874-94.

Rectus, Paul, b. 1847. French surgeon. Clinics, 1887.

Recluse. 1. Monk or nun occupying a sealed cell, ab. 1000-1300. 2. Nun of Port Royal. 17th century. 3. Any one living in retirement.

Recognition. Feeling of familiarity accompanying the presentation of an object which has already affected consciousness. It implies reproduction and comparison. When one recognizes a familiar face, the present object of consciousness, viz., the face itself, is compared with an image which is the result of previous experiences of the same face, and is itself recognized: this comparison results in the recognition, which is clear and complete according as the image is clear and complete. The object of recognition may be either a material object or an image. The recognition of an image depends upon the completeness of the reproduction of the circumstances and associations attendant upon the original perception.

Recognizance. Common law obligation entered into before a court of record or authorized magistrate, by which the obligor acknowledges or recognizes his liability; now regulated by statute.

Recollection. See Memory.

Reeollet. Branch of the Franciscan order, established 1592 in France; also of Augustinians, founded 1530, and others. The name marks a return to the original rule.

Reconciliation. Removal of estrangement between God and man, through the mediation or atonement of Christ.

Reconnaissance. Rough preliminary survey of a country to select an approximate location for a road or canal. Levels are taken by the barometer, angles measured by the prismatic compass, and distances determined by the pedometer or odometer.

Record, Robert. M.D.. 1510-1558. Physician to Edward VI. and Mary; introducer of the sign of equality in algebra; author of an arithmetic. Grounde of Arte*, 1540. and an algebra. Whetstone of Wit, 1557.

Recorder. 1. Class of judicial officers, having original criminal jurisdiction within a locality. 2. Officer, charged with making and keeping official written memorials and tran-! scripts of transactions.

Recording Acts. Modern statutes providing for the public record of conveyances of property, and prescribing the legal effect of such records.

Recoupcment. Legal defense which cuts down plain

tiff's claim, but does not entitle defendant to an affirmative judgment.

Recovery, Common. Obsolete method of conveying land by a lictitious suit.

Recruit. Person who voluntarily enlists in the army. See Enlistment.

Rectangle. Parallelogram having right angles only.

Rectification. Determination of the length of any curve or arc in terms of the rectilinear unit. Some familiar curves may be rectified geometrically, but the processes of the calculus are generally required.

Rectifying. Second and subsequent distillations of a volatile liquid, to free it from impurities which may have been carried over in the first distillation; particularly applied to alcohol.

Rectilinear, or Rectilineal. Composed of or bounded by straight lines.

Rectipctality. Tendency of vegetable organs to grow in straight lines when all external directive influences are removed.

Rector. In English Ch. and P. E. Ch.. incumbent of a parish; also in Scottish Episcopal Ch. since 1890; sometimes head of a ch., school, or other establishment. See Vicar.

Rectriees. Long tail-feathers of birds.

Rectum, Diseases Of. Those affecting the last division of the intestines. Inflammation of the part is known as proctitis; it may be the seat of malignant growths. See PROLAPSUS Ani and Hemorrhoids.

Recurring Equation. One in which the coefficients of terms equidistant from the extremes are the same, having the signs of the corresponding terms either all like or all unlike: e.g., x5—3x44-8x8-f-8x8—3x4-l=-0. A recurring equation of odd degree has -f-l or —1 as a root, as the corresponding terms have unlike or like signs; one of even degree, having all like signs, can be transformed to an equation of one-half the degree: one of even degree, having unlike signs and the middle term missing, has both -)-l and —1 as roots.

Recurring Sines. One each of whose terms after a certain number is related to a number of preceding terms through a sequence of multipliers which remains unchanged throughout the series. This sequence of multipliers is called the scale of relation, and the number of terms in the scale determines the order of the series. A geometrical progression is a recurring series of the first order, the constant ratio being the scale. A recurring series of the second order will have a scale of two terms and two terms given as a basis for the series. The scale of a recurring series of the nth order can be determined if 2n terms be known.

Recurvirostridw. See Limicol^.

Recusants. Those who fail to attend services of an Established Ch. Statutes of Elizabeth were in force against Protestant Dissenters till 1688, and against R. Catholics till 1791.

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after a desperate struggle. The English lost 71 officers and 2,450 in all; the French, 1.648 killed, including 5 generals and 140 officers, 4,500 wounded, and 1,400 missing. The Russians abandoned the s. part of Sevastopol the following night.

Redan. See Field Works.

Red Bud. See Judas Tree.

Red Cedar. See Cedar.

Red Cedar. River ab. 120 m. in length, rising in a series of small lakes in Wis., flowing s.w. and emptying into the Chippewa.

Red Chalk. See Hematite.

Red Copper Ore. See Cuprite.

Red Cross. Societies organized to succor the wounded and dying in time of war. At a conference in Geneva, Oct. 1863, a treaty was drawn up which, after some modifications in the convention of Aug. 1864, was signed before adjournment by representatives of 12 governments, a number now more than trebled. All hospitals, ambulances, materials, etc., under the Red Cross are treated as neutral. The American association (Clara Barton, pres.) aims also to relieve sufferers from fires, cyclones, famine, and other far-reaching calamities. The symbol of the various relief societies is a red cross on a white ground.

Red Deer. See Stag.

Reddle. See Hematite.

Redemption. Work of Christ for his people; variously interpreted in different ages and schools of theology; nearly equivalent to salvation, which is sometimes of more personal application. See Atonement.

Redemption!*!*, or Trinitarians. French order, confirmed by the Pope 1199, for the ransom of Christian slaves in the Barbary States.

Redemptoriats. Severe monastic order founded by Liguori in Italy 1732, confirmed 1749. It has manv houses in the U. S.

Redeadale. Valley of Northumberland, near the Scottish frontier, famous in border legends. The battles of Otterburn and Redeswire, 1575, were fought in the vicinity.

Redfleld, Isaac Fletcher, LL.D., 1804-1876. Judge Vt. Supreme Court 1835, Chief-justice 1852-60; prof. Dartmouth 1857-61. Law of Railways, 1857; Law of Wills, 1864-70; Law of Carriers, 1869.

Redfleld, Justus Starr, 1810-1888. American publisher.

Redfleld, William C, 1789-1857. American meteorologist, prominent also in connection with steamboats, railroads, and street railways.

Red Fire. Used in pyrotechnics; usually consisting of an intimate mixture of dry strontium nitrate, sulphur, potassium chlorate, and lampblack.

Redgrave, Richard, 1804-1888. English landscape and genre painter, R.A. 1851, Inspector-gen. of art schools 1857-80. Manual of Colors, 1863; Century of Painters, 1866; Reminiscences, 1891.

Red Hand, In Heraldry. Sinister hand granted to baronets in England and Ireland 1611, and now to those of the United Kingdom.

Red Hematite. Fe,Ot. One of the commonest of iron ores, in which the red color of the mineral or of its powder is a prominent character. See Hematite.

Red-hot Shot. Spherical shot heated to a red heat and fired from smooth-bore muzzle-loading cannon, to set vessels, wooden buildings, etc., on tire. Many of the masonry forts constructed in U. S. before the Civil war were provided with hot-shot furnaces: the use of rifled guns anil elongated projectiles have made hot shot an obsolete projectile.

Redia. See Distomum.

Rcdtf Pasha, b. 1827. Turkish officer, prominent in the war with Russia 1877; since in exile.

Reding, Aloys Yon, 1755-1818. Swiss patriot, who defeated the French at Morgarten 1798, opposed the Helvetic confederation, and was Landamman of Canton Schwyz 1803 and 1809.

Red Ink. See Ink.

Red Jacket, or Saooyewatha, 1751-1830. Seneca chief, distinguished for his eloquence and for his services to the U. S.

Red Lead. See Minium.

Red-Eetter Dajr8. In the Anglican Calendar, the days of the greater feasts were printed in red letters, and the lesser in black, whence the Black-Letter Saints' Days.

Red Eiquor. Solution of aluminium acetate in water: usually prepared by the action of solutions of acetate of lime and alum upon each other, when sulphate of lime is precipitated; used iu dyeing.

Redoubt. Important earthen field work, completely inclosing a position to be defended: generally of four or five faces, with sufficient interior space to lodge the temporary par


Taking a Turkish Redoubt at Loftcba, Bulgaria.

rison. When it is commanded by the defenses in rear its gorge is often stockaded, to prevent its being used b}' the enemy in the event of its capture. See FIELD WORKS.

Redpath, James. 1833-1891. Scottish-American journal ist and author; active against slavery; founder of lecture bureaus in Boston. John Brown, I860."

Red-Polled. See Cattle.

Red Precipitate. See Mercuric Oxide.

Red Prussian- of Potash. See Potassium Ferri


Red River. Branch of the Mississippi. It heads in the Staked Plains of Texas, flows generally e. between Texas and Indian Territory, then s.e. across a corner of Ark., and through La. to its mouth. Length 1,550 m., drainage area ab. 90.000 sq. m., average flow 57,000 cu. ft. per second.

Red River Expedition. Planned by Gen. Halleck: conducted by Gen. Banks, who started March 25, was defeated at Sabine Cross-Roads by Kirby Smith April 8, and began his retreat; defeated the Confederates at Pleasant Hill April 9. and reached Alexandria April 22.

Red River of the North. Heads in Lake Elbow on the boundary between Minn, and Dakota, flows n. into Canada.

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Red root. 1. Gyrotheca tinctoria. Woolly herb of the natural family Hcemodvracece. growing in swampy places in thee. U.S. 2. Certain shrubs of the genus Ceanothus, natural family Rhamnaceai, natives of N. America.

Redrulllile. Cu,S. Variety of the mineral chalcocite, occurring in well-formed crystals at Redruth in Cornwall.

Red Sea. Long narrow arm of the Indian Ocean, between Asia and Africa, separating Arabia from Egypt, the Soudan and Abyssinia. It connects with the Indian Ocean by the Strait of Babel Mandeb and the Gulf of Aden. Length 1,450 m., maximum breadth 230 m.

Red Seaweeds. See Alo.-k and Seaweeds.

Red Silver Ore. Common name for the minerals PyrarGYRITE and PROUSTITE (q.v.). The former is known as the dark red, the proustite as the light red ore.

Red Snow. Protocoeeus nivalis. Minute red plant of the sub-kingdom Protophyta, occurring abundantly in arctic and alpine regions, and superstitiously regarded as blood.

Red Sulphur Springs. Watering place in W. Va.. 38 m. s.w. of White Sulphur Springs. The water contains phosphorus and a gelatinous sulphur compound which is its distinctive feature.

Red Sunset. Peculiar rich and long-enduringsunset phenomena, observed, as also a red sunrise, throughout the n. temperate zone 1883, and enduring for three years, but slowly diminishing in intensity. Similar phenomena, but less extensively distributed, were observed 1831 and other years.

Red Top. Agrostis vulgaris. Pasture grass of n. hemisphere; in its habits somewhat similar to blue grass, but taller anil liner. It is especially adapted to moist and wet soils, and makes a fine hay of excellent quality.

Red Top, False. Poa serotina. Tall meadow grass of the n. hemisphere, known also as Fowl Meadow-Grass.

Redueed Length Of An Electric Conductor. Length of a column of mercury of one square millimeter cross section which offers the same resistance as the conductor.

Reduced Thickness Of A Dielectric. Thickness of a layer of air that would have the same inductive capacity as

the dielectric. It is equal to -j—, in which t is the thickness of

the dielectric and k its specific inductive capacity.

Reducing Agent. Substance which will readily abstract oxygen from other substances; e.g., hydrogen and carbon.

Reductio ad Absurdum. Process of reasoning by which a proposition is proved by proving the falsity of its contradictory opposite.

Reduction. Process occurring when a chemical compound containing oxygen gives up a portion or all of its oxygen to some other compound or element. When compounds containing other elements give up these, reduction is also said to have taken place; e.g., when FeCl, becomes FeCl,.

Reduction, In Mathematics. 1. Process of changing form without changing value or relations. 2. Process of reaching a result in general terms applicable to all cases under the form which is discussed.

Reduction Factor. See Galvanometer.

Reduplication. In Botany, regular doubling of flowers.

Reduplication. Repetition of part of the root of a verb in order to express change of tense; common in Greek and Latin, and even in Gothic; best shown in English by the preterit did from the present do.

Redwald. King of East Angles 597; Bretwalda.

Redwitz-Schmolz, Oscar, Freiherr Von, 1823-1891. Bavarian poet and novelist. Amaranth, 1849; Odilo, 1878; Hymen, 1887.

Red-Wood. Sequoia sempervirens. Very large tree of the natural family Coniferce, native of the Pacilic coast of the U. S.; extensively lumbered.

Redwood, Abraham, 1709-1788. Founder of the Redwood Library at Newport, R. I., 1747-50.

Reed. Phragmites phragmites. Large grass, growing in swamps in the n. temperate zone.

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Organ Recti. a. Bagpipe Reed. 6, Bassoon Reed.

called a free reed; e.g., that of a harmonium or concertina. If it is larger than the orifice and strikes against the edges at each oscillation, it is called a beating reed; e.g., that of the clarionet or bassoon. See Organ Pipe.

Reed, Andrew, D.D.. 1787-1862. Cong, pastor in London 1811-61. Some of his hymns, 1817-25-42, are widely used. — His wife, Eliza (holmes), 1794-1867, was also a hymnist.

Reed, David Boswell, M.D., 1805-1864. Scottish chemist and writer, interested especially in ventilation; in the U. S. from 1856.

Reed, Sir Edward James, b. 1830. English designer of ironclads; chief constructor of the navy ab.1860-70; M.P. 1874-92; knighted 1878. Japan. 1880.

Reed, Henry, LLD., 1808-1854. Grandson of Joseph; prof. Univ. Pa. from 1831. His Lectures on English Literature. 1855. and on the British Poets, 1857, were edited by his brother. William Bradford, 1806-1876, prof. Univ. Pa. 1850, Minister to China 1857-60, and biographer of Joseph Reed, 1847.—Henry's son, Henry, 1846-1896, was Judge of Common Pleas In Phila. from 1886. Statute of Frauds, 3 vols., 1884.

Reed, Joseph, 1741-1785. Sec. and aid to Washington 1775-78; active in several battles; Brig.-gen. 1777; delegate to Congress 1778; Pres. Pa. Executive Council 1778-81, and practically Governor. When offered a bribe of £10,000, he replied: "I am not worth purchasing, but, such as I am, the king is not rich enough to do it."

Reed, Thomas Brackktt, b. 1839. Attorney-gen. of Me. 1870-72; M.C. since 1877, and Speaker of the House 1889-91 and 1895-97; Republican leader.

Reed Rird. See Bobolink.

Rceder, Andrew Horatio, 1807-1864. First Gov. of Kansas 1854-55. He denounced the fraudulent Legislature, and by the Freesoilers was elected to Congress and the U. S. Senate, but not admitted.—His son, Frank, b. 1845, is prominent in Pa. Republican politics.

Reed Instruments. Generic name of a class of instruments, the tones of which are produced by a reed. They were known among the Chinese, but most are of modern invention. See Organ, Harmonium, and Melodeon.

Reed-IWace. See Cat-tail.

Reef. See Coral.—In Australia, auriferous quartz vein.

Reel. Scottish dance, varied in the Va. form.

Re-entrant Angle. Interior angle of a polvgon greater than 180°.

Re-entrant Polygon. One having one or more re-entrant angles.

Rees, or Arickarees. Indian tribe of Pawnee origin, which lived on the upper Missouri, whither they had migrated; unfriendly to the whites. They now number ab.1,000, on a reservation with the Mandans. See Pawnees.



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English local magistrate of former times.

Tr. Barclay's


Reeve, Clara, 1725-1803. English novelist. Argents, 1772; Old English Baron, 1777-78.

Reeve, HENRY, D.C.L.. 1813-1895. Registrar of Privy Council 1837-87; ed. Edinburgh fteview 1855; historical writer.

Reeve, Tapping. LL.D.. 1744-1823. Founder and head of the first law school in the U. S., at Litchfield, Conn., 17841820. Law of Baron and Femme, 1816; Law of Descents, 1825.

Reeves, JOHN, 1752-1829. Chief-justice of Newfoundland 1791-92 History of the Law of Shipping, 1792; History of English Law, 5 vols., 1784-1829.

Reeve*, John Sims, b. 1822. English singer, highly popular as a tenor 1847-91.

Reeving. Passing a rope through a hole or channel of a block made to receive it.

Re-exchange. Loss resulting from the dishonor of a bill of exchange in a different country from that where it is drawn or indorsed.

Refeelory. Dining hall or fratery, of a convent or college. The arrangements were similar to those of the ordinary


Refectory, Convent of St Catherine, Mt. Sinai.

domestic halls. It was usually provided with a pulpit, from which one of the inmates read to the others during meal time.

Referendum. Submission by the legislature of a proposed law to popular vote.

Rcflcctlng-Anemometer. Aime's apparatus, invented 1846, for observing the direction and velocity of motion of the clouds, i.e., of the upper winds. This and similar apparatus are now styled Nephoscope (q.v.).

Reflecting Power. Property of a surface by which it reflects regularly a greater or less proportion of the radiant energy incident upon it. Its value is the ratio of the energy reflected to the whole amount incident. This quantity is always inversely proportional to the absorbing power of the medium beyond the surface. The reflecting power increases with the angle of incidence. That for water at a perpendicular incidence, according to Bousruet. is ab. 0.018; for an incidence of 89.5° it is 0.721. Again the differences in the reflecting: powers of different substances are much more marked at small than at great incidences. Thus water and mercury reflect about the same proportion of the incident light at 89.5°, while at a perpendicular incidence mercury has a far higher reflecting power.

Reflecting Telescope. The image is formed by means of a concave mirror; the eye-piece may be placed in the focus of the mirror in front, or a reflector may be employed to throw the image back through an orifice in the mirror to the eye


Total Reflection.

piece placed behind it. Four different forms have been employed, the Newtonian, Gregorian, Herschelian, and CasseOranian (q.v.).

Reflection. Abrupt change in the direction of propagation of a wave front in an elastic medium when it is incident upon a surface. The laws of reflection are: (1) The Angle Of Reflection

(q.v.) is equal to the

Angle Of Incidence (q.v.): (2) the incident ray, the reflected ray, and the normal are all in the same plane. In the case of radiant energy these two laws apply to specular or regular reflection, such as takes place from polished surfaces. The phenomenon of total reflection takes place when a ray of radiant energy is incident upon the surface of a medium optically less devise, and at an alible greater than the critical tingle for that particular wave length.

Reflex Action.

Muscular or other activity caused immediate!y by a sensory impulse without the necessary intervention of consciousness; e.g., if the sole of the foot be tickled, the foot will be withdrawn; or if a foreign body approach the cornea of the eye, the eyelid winks. The necessary elements are a sensory impulse carried along a sensory tract, a reflex nervous center, and a motor tract and organ. The great center for reflex action is the spinal cord. Certain parts of the brain however have reflex functions. The most marked feature of reflex actions is their purposeful character, the kind of activity being determined largely by the kind of sensory impulse. This c haracteristic is a strong support for the theory that reflexes were originally voluntary movements of a purposeful kind, which became habitual and involuntary, and are now inherited. The character of the reflex movement is also influenced by the intensity of the stimulus, a slight stimulus calling out one movement, and a strong stimulus at the same spot calling out a response quite different. Further, the movement varies according to the part of the body stimulated; e.g., a cinder in the eye may cause active winking, while the same body on the mucous membrane of the larynx will bring about violent reflex coughing, directed toward the expulsion of the irritating substance. Reflex actions may be partly or wholly arrested by act of will or by another sensory impulse. The time required for a reflex act varies with the act and with the stimulus, the greater part of the whole time being taken up in the central change by which the sensory is transformed into a motor impulse. The nature of this central function is unknown. Certain of these reflexes are absent in diseased conditions, others are not present in health. Consequently, a study of the reflexes assists in determining the presence of some diseases.

Reflex Sentiment*. Those feelings and desires which arise from our recognition of other men's feelings toward ourselves, as our desire of esteem, the love of fame, or of glory.

Reformat ion. Movement, first conspicuous under Luther

1517, by which a great part of western Christendom was rent away from ecclesiastical obedience to Rome. It was most effective in Germany, Switzerland, Holland, the Scandinavian countries, Scotland, and England. In Spain and Italy it was stamped out; in France it occasioned the Huguenot wars; in Bohemia, where it had been anticipated by a century, its fruits were destroyed, as in parts of Germany, by the Thirty Years' War.

Reformatories. See Prison and Prison Discipline.

Reformed Church In The United States. Organized 1747: called German Reformed till 1867. It has ab. 950 ministers and 225,000 communicants.

Reformed Church Of America. Organized in New Amsterdam 1628; called Reformed Protestant Dutch till 18S7; especially stronsj near the Hudson. Ministers ab. 620, communicants above 100,000.

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