dominis arises from the pubes, and is inserted into the three inferior true ribs. The Rectus femoris arises by two heads from the ilium and acetabulum, and is inserted into the patella. Recurrent (Lat.), in anatomy, an epithet applied to a branch of the posterior tibial artery, and of the inferior laryngeal nerves. In crystallography, a recurrent crystal is one whose faces, being counted in annular ranges from one extremity to the other, furnish two different numbers which succeed each other several times, as 4, 8, 4, 8, 4.-In algebra, a recurring series is one in which the coefficients of the successive powers of x are formed from a certain number of the preceding coefficients.In arithmetic, recurring decimals apply to figures which are continually repeated in the same order. Recurviros'ter (Lat. recurvo to bend back, and rostrum the bill), a bird whose beak bends upwards.

Recurvirostri'ne (Lat.), in ornithology, a sub-family of Wading birds, of the order Grallæ.

Red (Sax. reod) is one of the primary colours, the rays of which it is formed being the least refrangible in the solar beam.-In geology and mineralogy, red antimony is a mineral of a cherry-red colour and foliated fracture. It consists of I atom of oxide of antimony, and 2 atoms of the sesquisulphide of antimony: sp. gr. 409; H = 1-1.5.-Red sandstone is a term used as expressing rocks of certain geological periods, viz., that preceding the carboniferous or mountain limestone, and that succeeding the magnesian limestone. These groups of rocks are termed the old and the new red sandstones. - Red-lead, red oxide of lead, the minium of commerce; it. is employed as a pigment, and also in the manufacture of glass. -Red copper, a mineral of various shades of red, consisting of oxide of copper.-Red ochre, a soft earthy variety of hematite; a peroxide of iron. Red precipitate, the peroxide of mercury, obtained by the decomposition of nitrate of mercury by heat.-Red vitriol, the disulphate of cobalt, a mineral of a vitreous lustre. - Red zinc, manganesian oxide of zinc, a translucent mineral occurring in foliated grains, and composed of oxide of zinc and sesquioxide of manganese: sp. gr. 5.43; H=4.-Red manganese, in mineralogy, a rose-red or brownish mineral, consisting chiefly of carbonate of manganese.-Red silver

ore, a mineral of a black colour, consisting of sulphur, antimony, and silver.-Red coral, the Corallium rubrum, a branch Zoophyte. Redan (Fr.), in fortification, a kind of rampart placed in advance of the principal works to defend the least protected parts.

Red Gum, in pathology, a disease incident to children newly born. Red-gum Tree, in botany, a lofty evergreen timber tree of New Holland, which produces a gum resin useful for medical purposes. Reduction (Lat.), in arithmetic, the proceeding of changing the quantity of one denomination into an equivalent quantity in another denomination. In algebra, reduction of equations is the clearing them of all superfluous quantities, and bringing them to their lowest terms.-In practical geometry and drawing, the reduction of a figure, design, or draft is the making a copy of it either larger or smaller than the original, still preserving the form and proportion. In metallurgy, the process of converting a metallic oxide into metal by expelling its oxygen. In surgery, the restoration to its place of a dislocated bone or other part.

Reed Organ, in music, an organ in which the keys open valves, that allow the wind from the bellows, worked by the feet of the performer, to act on the reeds. Reef Lines, in nautology, small ropes used to reef the courses, by passing them spirally through the holes of the reef and over the head of the sail alternately from the yards to the slings. Reflecting Dial, a kind of dial which shows the hour by means of a mirror so placed as to throw the sun's rays to a part of a ceiling on which the hour lines are drawn. Reflecting goniometer, an instrument for measuring the angles of crystals by means of rays of light reflected from their surface.

Reflecting Telescope, a telescope in which the rays from the object to be viewed are first received on a speculum, or reflecting surface, thence passing to another speculum, and so to the eye.

Reflection (Lat.), in physics, the resilition of a rapidly-moving body, as light, from the surface of another body, by which its progress is arrested at an angle equal to that of its incidence. The angle of reflection is the angle at which a ray of light leaves a reflecting surface.

Reflex (Lat. re, and flecto to bend), in physiology, a term applied to a class of actions in which an impression is carried by a nerve to a nervous centre. In painting, the illumination of one body by light reflected from another.

Refraction (Lat.), in optical science, the deviation of a ray of light from its previous course in entering a medium of a different density.Astronomical refraction is the apparent angular elevation of the celestial bodies above their true places, caused by the refraction of the rays of light in their passage through the earth's atmosphere.-Angle of refraction, the angle made by a ray of light and a perpendicular to the surface of the medium through which it is passing.-Double refraction is the separation of a ray of light into two distinct parts by passing through certain media, as Iceland spar. Nearly all crystals exhibit double refraction.

Regel, or Rigel, in astronomy, a star of the first magnitude in the constellation Orion.

Regard'ant (Fr.), in heraldry, an epithet applied to any animal whose face is turned toward the tail in an attitude of vigilance.

Reg'imen (Lat. a rule), in physiology, the regulated use of aliments, and of everything essential to life, in health and disease.

Reg'ister Pyrom'eter, an instrument for measuring high temperatures by the lineal expansion of bars of metal.

Reglet (Fr.), in architecture, a flat narrow moulding, used chiefly to separate the parts or members of compartments or panels from each other. Reg'ular (Lat. regularis), an epithet of frequent use in science. In geometry, a regular figure is one in which all the sides and angles are respectively equal. A regular body, or regular solid, is a body which has all its sides, angles, and planes respectively, similar and equal, of which bodies there are only the five folowing: the tetrahedron, contained under four equilateral triangles; the hexahedron, or cube, contained under six squares; the octahedron, under eight triangles; the dodecahedron, under twelve pentagons; and the icoscahedron, contained under twenty triangles. Regular curves, in geometry, are such as the perimeters of conic sections, which are always curved after the same geometrical manner.

Reg'ulus (Lat.), in astronomy, a star of the first magnitude in the constel

lation Leo. -In metallurgy, the name of a metal in a refined metallic state, or that in which it is separate from all extraneous matter: now principally applied to the regulus of antimony and arsenic. Relief Valve, in pneumatics, a valve in an air-pump to prevent the momentary condensation of air in the receiver when the piston descends. Reliq'uise (Lat.), in geology, fossil remains of substances found in dif

ferent parts of the globe.

Rem'olinite, a mineral composed of oxide of copper, chloride of copper,

and water.

Ren'uent (Lat.), in anatomy, an epithet applied to two muscles which serve to throw the head back. Renverse (Fr. renverser to reverse), in heraldry, applied to anything set with the head downwards, as a chevron with the point downwards. Reom'eter (Gr.), in electricity, an instrument for ascertaining the presence and measuring the force of electrical currents; a galvanometer. Re'otrope (Gr.), in electricity, a term applied to instruments of various construction for reversing the direction of an electric current.

Repeater (Lat. repeto to seek again), in arithmetic, a decimal in which the same figure continually recurs. Repeating Circle, an astronomical instrument by which the errors of graduation may be diminished in any degree, by repeating the observation, reading it off successively on different parts of the graduated limb, and taking the mean of the values thus found.

Rep'etend (Lat.), in arithmetic, that part of a circulating decimal which is continually repeated. Reptil'ia (Lat. reptilis creeping), in zoology, an order embracing the Chelonia, or Tortoises; the Sauria, or Lizards; the Ophidia, or Serpents; and the Batrachia, or the Toads and Frogs.

Rer'edos (Fr.), in architecture, a screen or division wall placed behind an altar, rood-loft, &c., in old churches. Reseda'ceæ (Lat. resedo to appease), a nat. order of herbaceous Exogens, of which Reseda, or Mignonette, is the type.

Resid'uum (Lat.), in chemistry, the residue, or what is left, in any chemical process.

Resin (Fr. résine, from rheo to flow), a vegetable principle exuding from certain trees, inflammable, hard when cool, and viscid when heated. There are many varieties of resin-their general characters being fusibility and inflammability, solubility in alcohol, and insolubility in water.Highgate resin is a mineral discovered during an attempt to pass a tunnel through Highgate Hill: sp. gr. 1'046; H=2.5.-Resinous electricity is that kind of electricity which a tube of resin exhibits by friction on a rubber of wool, otherwise called negative electricity.

Res'inone, a product somewhat resembling alcohol, which differs from oil of turpentine in containing an additional atom of water.

Resolution (Lat. re, and solvo to loosen), in chemistry, the process of separating the component parts of bodies. In pathology, the subsidence of inflammation without abscess, ulceration, mortification, &c. -In algebra, resolution of equations is the finding of the values which the unknown quantity or quantities must have, so as to fulfil the conditions expressed in the proposed equation. In geometry, the orderly enumeration of the things to be done to obtain what is required in a problem. -In mechanics, the resolution of forces is the act of finding the quantity of two or more forces or motions, which, taken together, shall produce a given resultant.

Resolve (Lat.), in algebra, to resolve an equation is to find the values which the unknown quantity or quantities must have, in order to fulfil the conditions of the problem.

Resol'vend (Lat.), in arithmetic, a number which arises from increasing the remainder after subtraction, in extracting the square or cube root.

Resolvent (Lat.), that which causes solution. In pathology, a substance employed to allay inflammation, and prevent suppuration.

Rest, in music, a pause or interval of time, during which there is an intermission of the voice or sound. -In physics, the continuance of a body in the same place when acted on by equal and opposing forces.

Restia'ceæ (Lat. restis a cord), a nat. order of plants, of which Restio is the type. They are used as cords at the Cape of Good Hope.

Resultant (Lat. resulto to leap back), in dynamics, the force which results from the composition of two or more forces acting upon a body.

Rete (Lat. a net), a term frequently applied in anatomy and natural history to cellular membranes, nerves, vessels, and other parts which have a retiform appearance. In anatomy, rete mirabile, a network of bloodvessels at the base of the brain of

quadrupeds;-Rete mucosum, the soft and apparently fibrous matter or layer situated between the cuticle and the cutis; it is the seat of the colour of the skin, which in the negro is black.

Reten'tion (Lat.), in pathology, the power of retaining, or that state of contraction of the elastic or muscular parts of the body by which they hold their proper contents, and prevent evacuation.

Retia'res (Lat. rete), in entomology, those spiders which spin a web or net to entrap their prey. Reticula'ta (Lat. reticulum a little net), the name of a section of Lithophytes. -In architecture, reticulated work is a species of masonry formed of small square bricks or stones placed lozenge-wise.

Reticulum (Lat.), in comparative anatomy, the second cavity of the complex stomach of the ruminant quadrupeds, so called from the reticulate or honeycomb-like disposition of the sub-hexagonal cells which occupy its inner surface.

Retina (Lat. from rete a net), the netlike expansion of the optic nerve; the seat of vision.

Retinaculum (Lat. a band), in botany, the viscid matter by which the pollen masses in Orchids adhere to a prolongation of the anther.

Retin'alite (Gr. retine resin, and lithos a stone), a translucent mineral of a brownish-yellow colour, consisting of silica, magnesia, soda, peroxide of iron, alumina, and water: sp. gr. 2'493; Η = 3.75.

Retinas'phalt (Gr. retine andasphaltos), a mineral of a pale brownish-yellow colour; composition-resin, asphalt, and earthy substances: sp. gr. I'I1'2; H = 1'0-2.0.

Retinite (Gr. retine), a resinous substance found in some kinds of coal. Retinitis (Lat. retina), in pathology, inflammation of the retina of the

eye.

Ret'irade (Fr. retirer to retire), in fortification, a kind of retrenchment in the body of the bastion or other work.

Retort (Lat. re, and torqueo to twist), in chemistry, a globular vessel with a long neck employed in distillation. Retro- (Lat.), a preposition used in compound words, signifying back or backward.

Re'troflex (Lat. retro, and flecto to bend), in botany, bent backwards. Re'trofract (Lat.), in botany, hanging back and down, as if broken. Retrograde (Lat. retro, and gradior to step), in astronomy, apparently moving in the direction contrary to the order of the signs of the zodiac in which the sun appears to move.

Retrogres'sion (Lat.), in astronomy, the change of position undergone by the moon's nodes, in a direction contrary to the motion of the sun.

Retromin'gent (Lat. retro, and mingo to urinate), discharging the urine backwards; an animal staling backwards.

Return (Fr. retourner), in architecture, the continuation of a moulding, projection, &c., in the opposite direction. In fortification, the returns of a trench are its several windings and lines.

Retuse (Lat. re, and tundo to bruise), in geometry, having a broad and slightly depressed apex.

Reus'site (from M. Reuss, the German mineralogist), in mineralogy, a substance containing sulphates of soda and magnesia.

Reveille (Fr. awake), in military affairs, the beat of drum about daybreak to arouse the soldiers.

Reverberatory (Lat. re, and verbero to beat back), in chemistry and metallurgy, applied to a furnace in which a crucible or other object is heated by flame or hot air reverberated or beaten back from the roof.

Revet'ment (Fr.), in fortification, a strong wall built round the lower part of the rampart.

Reve'tus, in fortification, works constructed with stone or brick. Revolution (Lat. revolvo to turn about), in physics, the circular motion of a body on its axis; the motion_of any body round a fixed point. In geometry, the motion of any figure round a fixed line as an axis; thus a rightangled triangle, revolving round one of its legs as an axis, generates a

cone.

Rhabdol'ogy. (See Rabdology.) Rhamna'ceæ (Gr. rhamnos a branch), a nat. order of exogenous plants, of which the Rhamnus, or Buckthorn, is the type. Rhamphastidæ. (See Ramphastidæ.) Rhapon'ticine, in chemistry, a substance obtained from the Rheum rhaponti

cum.

Rhat'any, in pharmacy, the root of the Krameria triandria, imported from Peru, used as an astringent.

Rheine (Lat. rheum rhubarb), an inodorous, bitterish substance of a yellow colour, obtained by gently heating powdered rhubarb with 8 parts of nitric acid.

Rhenite, a translucent, vitreous mineral found at Rheinbreitbach, near Bonn, on the Rhine, consisting of

phosphoric acid, oxide of copper, and water: sp. gr. 42-43; Η = 5.0. Rheometry (Gr. rheo to flow, and metron a measure), in mathematics, the differential and integral calculus. -Rheometer is an instrument by which the force of an electric, magnetic, or galvanic current is measured.

Rheostat (Gr. rheos a current, and istemi to stand), in galvanism, an apparatus for enabling a galvanic needle to be kept at the same point during an experiment.

Rhe'otome (Gr. rheos, and temno to cut), in electricity, an instrument for periodically interrupting an electric current.

Rhe'otrope (Gr. rheo, and trepo to turn), in electricity, an instrument for reversing the direction of a voltaic current.

Rheumatism (Gr. rheuma a watery humour), in pathology, pain and inflammation about the joints and surrounding muscles ;-Articular rheumatism, occurring in the joints and muscles of the extremities;-Lumbago, in the loins;-Sciatica, in the hip-joint;-Spurious pleurisy occurs in the muscles of the diaphragm. Rheumic, in chemistry, an epithet denoting an acid obtained from rhubarb stalks.

Rhexis (Gr. a bursting), in pathology, the rupture of a vein, or the spontaneous bursting of a purulent collection.

Rhinantha'cese (Gr. rhin a snout, and anthos a flower), a nat. order of herbaceous plants, of which Rhinanthus, or Yellow-rattle, is the type. Rhinocarcino'ma (Gr. rhin, and karkinoma cancer), in pathology, cancer of the nose.

Rhinoplasty (Gr. rhin, and plasso to form), in pathology, the operation for forming a new nose.

Rhinopoti'næ, a sub-family of flat fishes; fam. Raidæ. Rhipip'tera (Gr. rhips a fan, and pteron a wing), in entomology, an order of insects having only two wings folded like a fan.

Rhizanths (Gr. rhiza a root, and anthos a flower), in botany, a class of plants occupying a position between the flowering and the non-flowering species. Rhizocarpous (Gr. rhiza, and karpos fruit), an epithet applied to plants whose branches perish every year, but whose roots last many years. Rhizopods (Gr. rhiza, and podes feet), in natural history, a class of simple organic beings, consisting of minute gelatinous masses, often provided