colour, with a white streak, consisting of silica, alumina, lime, soda, magnesia, peroxide of iron, and oxide of manganese: sp. gr. 3.0.

Ermine (Fr.), in natural history, an animal about the size of a squirrel, a species of polecat, valued for its fur. -In heraldry, Ermine is represented by a white field or fur with black spots, and is supposed to denote the linings of mantles and robes.

Erotyl'ide (Gr. erotylos amatory), a family of monilicorn coleopterous insects, of which Erotylos is the type and genus.

Erpetology (Gr. erpetos a reptile), a treatise on reptiles.

Erran'tes (Lat. errans wandering), a family of Annelids, consisting of several tribes and numerous genera; they are all marine animals, and generally dwell beneath stones, or are buried in the sand.

Erratic (Lat. not fixed), in geology, Erratic blocks is a term used for those transported boulders which are so largely and so confusedly mixed up in what is termed the Diluvium. Eruption (Lat.), in pathology, an efflorescence of the skin; an acute cuta neous disease.

Erycin'ide (from Erycina, a name of Venus), in entomology, a family of beautiful lepidopterous insects, containing the genera Erycina, Polyommatus, and Thecla.

Erysipelas (Gr. eryo to draw, and pelas adjoining), in pathology, an inflammatory disease of the skin, vulgarly called Rose, from its redness. It is generally attended with vesications on the afflicted part, and with symptomatic fever. Its species are E. phlegmonodes, phlegmonous; E.ædematodes, edematose; E. gangrene, gangrenous; E. erraticum, wandering.

Erythe'ma (Gr. erythros red), in pathology, a morbid redness of the skin, generally terminating in scales, and sometimes in gangrene. The different species are E. fugax, fugacious; E. lave, sinooth; E. marginatum, marginated; E. papulatum, papulated; E. tuberculatum, tuberculated; E. nodosum, nodose; E. intertrigo, fret or erosion of the skin.

Erythroliť mine (Gr. erythros, and litmus), in chemistry, a red substance obtained from litmus. It is soluble in hot alcohol, and dissolves in alkalies with a blue colour.

red seeds; erythroceras, having red antennæ; erythropectinus, having antennæ pectinated and ferruginous in appearance; erythrogaster, having a red abdomen; erythrogrammus, marked with red rays; erythroleucus, being red and white; erythrolophus, having a red crest or tuft; erythromelas, red and black; erythronotus, having a red back; erythrophthalmus, having red eyes; erythrophyllus, having red leaves; erythropterus, having red wings; erythropygius, having a red croup; erythroramphus, having a red beak; erythrorhynchus, having a red snout; erythrosomus, having a red body; erythrospermus, having red seeds; erythrostomus, having a red mouth; erythrothorax, having a red breast. Erythroxyla'cese (Gr. erythros red), in botany, a nat. order of hypogynous Exogens, of which the Erythroxylon is the type and genus. The wood and the juice of the fruit are generally

red, whence the name.

Escalade' (Fr.), in military science, the act of scaling the walls of a fortification by the use of scaling-ladders. Escape'ment (Fr.), in horology, that part of the mechanism of a watch or clock by which the circulating motion of the wheels is converted into a vibrating motion.

Escarp (Fr.), in fortification, the side of a ditch forming the exterior of a rampart.-Escarpment, in geology, is the abrupt face of a ridge of high land.

Eschar (Gr.), in pathology, a crust or scab made by a burn or some caustic application.-Escharotic is a term applied to a caustic application. Escutch'eon (Fr.), in heraldry, a shield of a family on which arms are emblazoned.

Esophagotomy (Gr. oisophagos the throat, and temno to cut), in surgery, the operation of making an incision into the œsophagus, for the purpose of removing any foreign substance. Esophagus, or Esophagus (Gr.oiso, and phago to eat), in anatomy, the passage leading from the pharynx to the stomach, by which the food is conveyed.

Esplanade' (Fr.), in fortification, the sloping of the parapet of the counterscarp, or covert-way, towards the open country; a glacis.

taste the rules and principles of art; the science which treats of the beautiful in nature and art.

Ete'sian (Lat.), in physicology, an epithet applied to certain winds which blow at particular times of the year.Etesian winds are yearly or anniversary winds, answering to the monsoons of the East Indies.

Ethal, in chemistry, a substance formed by the saponification of spermaceti. Ether (Gr. aither), in physics, an element supposed to be much finer and rarer than air, and to occupy the heavenly space from the termination of the atmosphere. In chemistry, a highly volatile, fragrant, inflammable, and intoxicating liquid, produced by distilling equal weights of sulphuric acid and alcohol. The different ethers are the acetic, oxalic, chloric, hydriotic, hydrochloric, hydrobromic, sulphuric, methylic, muriatic, carbonic, cyanic, benzoic, and chlorobenzoic. Etherification is the process of producing ether by the union of an alcohol and an acid.-Ethereum, or Etherine, is a carburetted hydrogen.

Ethics (Lat. ethicus), the science of moral philosophy, which treats of human actions and mental affections.

Ethion'ic Acid, a bisulphate of ether. Eth'moid (Gr. like a sieve), in anatomy, one of the eight bones composing the cranium, situated in the os frontis.

Ethnography (Gr. ethnos a nation, and graphe description), the science that describes the different races of mankind, or the different nations.Ethnology is a treatise on them.

Ethule (Gr. aither and ule matter), in chemistry, the elementary carbon and hydrogen of ether. It is the hypothetical base or radicle of the ethers. With oxygen, ethule forms ether, the oxide of ethule. Alcohol is the hydrate oxide of ethule.

Etiology (Gr. aitia cause, and logos discourse), that branch of pathology which treats on the causes of disease. Eu, a Greek particle prefixed to numerous words connected with science and art, and signifying good or well; as, Euaimia, a healthy condition of the blood.-Euchylia, in physiology, a healthy condition of the chyle.

Euchlore (Gr. eu, and chloros green), in mineralogy, having a distinct green colour.

Eu'chlorine (Gr.), the oxide of chlorine. Eu'chlorite (Gr.), a mineral containing water and copper. Eu'chroite (Gr.), a mineral of a light emerald - green colour, containing copper and arsenic.

Eu'chrome (Gr.), a compound of zinc and euchloric acid.

Eu'chymy (Gr.), a good state of the humours of the body. Eu'clase (Gr. eu, and klao to break), a very rare mineral, brought in small greenish crystals from S. America. Eu'crasy, a good temperament, or healthy state.-Eupepsy, a good digestion. Euphlogia, in pathology, a healthy kind of inflammation. Eudiom'etry (Gr.), the art of ascertaining the salubrity of the air.-Eudiometer is an instrument to measure the purity of gas.

Eudyalite (Gr.), a mineral found both crystallized and massive. Eugenia (Gr.), in astronomy, the name of one of the newly-discovered planets, first observed by Goldschmidt in 1857.

Eu'kairite (Gr.), a seleniuret of silver and copper.

Eu'lebrite (Gr.), a seleniuret of zinc. Eumen'idæ (Lat. the Furies), a family of hymenopterous insects. Euno'mia (Gr.), the name of one of the newly-discovered planets, first observed in 1851.

Eu'phonon (Gr. eu, and phone sound), a musical instrument of great sweetness and power.

Euphorbia'ceæ, a nat. order of Exogens, of which Euphorbium is the type. Euphros'yne (Gr.), the name of one of the newly-discovered planets, first observed in 1854. Euplexop'tera (Gr.), in entomology, an order of insects comprehending the Earwigs.

Euroclydon (Gr. euros the east wind, and klydon a wave), a dangerous easterly wind in the Mediterranean. Euro'pa, the name of one of the newlydiscovered planets, first observed in 1858.

Eu'rythmy (Gr. eu, and rhythmos harmony), in architecture, just harmony of the parts of a building.-In medicine, regularity of the pulse. Eustachian (from Eustachius the discoverer), in anatomy, denoting a tube which runs from the inner tympanum of the ear to the nostrils, and supplies the drum of the ear with air. Eustyle (Gr.), in architecture, the position of columns in an edifice. Euterpe, in astronomy, the name of one of the newly-discovered planets. Eux'enite (Gr.), a Norwegian mineral. Evaporom'eter (Lat.), an instrument to ascertain the quantity of evaporation in a given time. Ever'ticule, Evertic'ulum (Lat. everto to turn out), in surgery, an instrument used for clearing the bladder from calculous particles.

Ev'olute (Lat. e and volutus, unrolled), a curve formed by the end of thread unwound from another curve, the radius or curvature of which is constantly increasing.

Evolution (Lat.), the act of unrolling or unfolding.-In geometry, the unfolding or opening of a curve.-In arithmetic, the extraction of roots of any power. In military tactics, movements by which the disposition of troops is changed. In algebra, evolution is the reverse of involution, as, 4 is the root of 16, and 12 the root of 144.-In physiology, the theory of generation, in which the germ is held to pre-exist in the parent, and each part to be unfolded and expanded, but not actually formed, by the act of procreation.

Exæ'resis (Gr. exaireo to remove or take out), that part of surgery which relates to the removal of morbid or superfluous parts of the body. Exan'thema, or Exan'thesis (Gr.), in pathology, an efflorescence or eruption of the skin; a rash.-Exanthemata denotes a certain class of diseases, under which are comprehended the genera Rubeola, Scarlatina, Urticaria, Purpura, Rosolea, and Erythema. Exanthematology is a treatise on eruptive fevers.

Excitomo'tary (Lat.), in physiology, causing motion in animal bodies independent of sensation or volition. Brande.

Exentera'tion (Lat. from Gr. enteros), the act of taking out the bowels.

Exergue (Fr.), in numismatics, the basis of a coin or medal, which usually gives the date, place, &c., of the coin.

Exfœta'tion (Lat. ex, and fætus), imperfect fætation in some organ exterior to the uterus.

Exin'tine, in botany, a membrane situated between the extine and the intine in the pollen of the yew, juniper, cypress, &c.

Exo, a Greek preposition of very frequent use in scientific terms to denote outside of, or outward; as, Exo-skeleton, &c.

Exogastritis (Gr. exo, and gaster the stomach), inflammation of the external membrane of the stomach.

Ex'ogen (Gr. exo out, and gennao to grow), in botany, a plant or tree which increases in diameter by the addition of new wood to the outside of the old wood. Exogens are the first class of the grand division of the vegetable kingdom. The term Dicotyledons is also applied to this class.

Exom'phalos (Gr. omphalos the navel),

hernia or rupture at or near the navel.

Exophthalmia (Lat. from Gr. ophthalmos the eye), the protrusion of the eyeball from the orbit.

Exophyllous (Gr. exo, and phyllon a leaf), in botany, naked, as the leaves of Exogens.

Exorhi'ze (Gr. exo, and rhiza a root), in botany, plants whose radicles elongate downward.

Exos'mose (Gr.ex, andosmos impulsion), in anatomy, the passage of one fluid to another through a membrane from within.

Exos'tome (Gr.exo, and stoma a mouth), in botany, a passage through the outer integument of an ovule.

Exosto'sis (Gr.), in anatomy, an unnatural protuberance or tumour of the bone.

Exotic (Gr. exotikos foreign), in botany, foreign; not produced at home; an epithet applied, in natural history and materia medica, to animals, plants, and medical agents, the product of foreign countries; a plant of foreign origin.

Expectoration (Lat. ex, and pectus the breast), the discharge of mucous or other fluids accumulated on the surface of the bronchial membrane; the matter expectorated. - Expectorant is a medicine promoting expectoration.

Experiment (Lat.), in physiology, a term applied to the venesection of animals for the purpose of making discoveries in the structure and functions of their various organs.In pathology and medical jurispru. dence, a trial made on a man or other animal with a new medical agent or alimentary substance, in order to determine its operation or properties. Experimental philosophy comprehends those branches of science the deductions in which are founded on experiment. The principal experimental science is chemistry; but there are many others, as optics, pneumatics, hydrostatics, electricity, magnetism, &c.-Experimentum crucis (experiment of the cross) is a term applied in science to any leading or decisive experiment subjected to the severest tests; or such an experiment as leads to the true knowledge of things sought after, in the same manner as the cross on the highway directs the traveller in his course.

Expo'nent (Lat.), in algebra, the index of a power, as 2 is the exponent of 82, and 4 the index of x. The exponent of the ratio or proportion between two numbers or quantities is the quotient arising when the antecedent is divided by the consequent. -Exponential calculus, in fluxions, is the method of differencing or finding the fluxions of exponential qualities. Exponential curve is a curve the nature of which is defined or expressed by an exponential equation. Exponential equation is one in which is contained an exponential quantity, as the equation a2 = b, or xx = a, a, &c. - Exponential quality is that whose power is a variable quantity, as the expression ax, or xx. -Exponential quantities are of several degrees: ax of the first order xwy of the second, and so on.

Expressed Oil, in chemistry, an oil obtained by the mechanical operation of pressing or squeezing, instead of by boiling; thus castor, olive, almond, and cocoa-nut oils are obtained by being expressed.

Expres'sivo, Espres'sivo (Ital.), in music, a term indicating that the movement or passage over which it is placed is to be performed with expression. Exten'sor (Lat. ex, and tendo to stretch out), a term applied to certain muscles, whose property is to stretch out.

Extine, in botany, the outer coat of the pollen grain.

Extract (Lat. extractum), in pharmacy, the product of the evaporation of a fluid obtained by the expression of either animal or vegetable substances. In chemistry, a peculiar substance supposed to form the active principle of the vegetable in which it occurs.Of the numerous extracts used in the pharmaceutical laboratory the following may be enumerated, in alphabetical order, as among the principal ones:-Extractum aconiti, extract of aconite; E.aloes purificatum, purified extract of aloes; E. anthemidis, extract of chamomile; E. belladonna, extract of belladonna; E. cinchona, extract of bark; E. cinchonæ resinosum, resinous extract of bark; E.colchici aceticum, acetic extract of meadow saffron; E.colchicicormi, extract of the cormus, or meadow saffron; E. colocynthidis, extract of colocynth; E. colocynthidis compositum, extractum catharticum; E. conii, extract of hemlock; E. digitalis, extract of foxglove; E. elaterii, extract of elaterium; E. gentianæ, extract of gentian; E. glycyrrhiza, extract of liquorice; E. hæmatoxyli, extract of logwood; E. hyoscyami, extract of henbane; E.jalapæ, extract of jalap; E. lactuca, extract of lettuce: E. lupuli, E. humuli, extract of hops; E. opii purificatum,

extract of opium; E. papaveris, extract of white poppy; E. pareira, extract of pareira; E. rhei, extract of rhubarb; E. ruta, extract of rue; E. sarsaparilla, extract of sarsaparilla; E. stramonii, extract of thorn-apple; E. taraxaci, extract of dandelion.

Extraction (Lat.), in surgery, an operation by which foreign or diseased parts are removed by the natural or by artificial openings, as a bone from the œsophagus, or a calculus from the bladder.-In chemistry, the art of separating a simple or compound substance from a body of which it is a component part.-Extraction of roots, in arithmetic and algebra, is an operation which consists in finding a certain root of a number or algebraic symbol; as, 7 is the root of 49, and x is the root of x2. Extra'dos (Sp. or Fr.), in architecture, the exterior curve of an arch.

Extra-u'terine, in midwifery, an epithet applied to those cases of pregnancy in which the fœtus is contained in some organ exterior to the uterus. Extravasa'tion (Lat. extra and vas, out of the vessel), in pathology, the escape of the animal fluids, especially of blood or serum, from their natural vessels, and their consequent effusion into the meshes of the adjoining tissue.

Exulcera'tion (Lat.), in surgery, the process of ulceration caused by some caustic or irritating application. Exu'viæ (Lat.), the cast skin of animals, or whatever is put off or shed and left by animals or plants. In geology, the remains of natural objects deposited during the changes of the earth's crust.-Exuviation is the casting or throwing off the skins of certain animals; the process by which the Crustacea throw off their old shells.

Eye (Sax. eag), the organ of sight or vision; the most important feature of animal organization; the globe or ball, movable in the orbit, chiefly consisting of the cornea, the sclerotica, and the retina-the external parts being the eyebrows, the eyelid, and the eyelashes. The Cornea is a small segment of a small sphere; the Sclerotica is a fibrous membrane of great firmness, which gives form and support to the eyeball; the Retina is the expansion of the optic nerve lining the choroid.-In architecture, eye is a general term, signifying the centre of a part;-the eye of a pediment is a circular window in its centre; the eye of a dome, the horizontal aperture on its summit,

usually covered with a lantern;-the eye of a volute, the circle at the centre, from the circumference of which the spiral line commences.In horticulture, eye is a term applied to the leaf-bud, from which some other individual plant may be propagated.

Eye-bolt, in nautical science or art, a

Faba'cese (Lat. faba a bean), in botany, a nat. order of herbaceous plants, of which the Faba, or common esculent bean, is the type and genus. Fabra'rum Aqua (Lat. smiths' water), a name applied to a chalybeate produced by quenching red-hot iron in water; commonly known as forge

water.

Façade (Fr.), in architecture, the elevation or front view of an edifice. Face (Fr. from Lat. facies), a term of frequent use in practical science and the arts. In zoology and anatomy, it applies to the anterior portion of the head of a mammiferous animal. The face of birds comprehends the cheek, temples, eyes, forehead, and vertex; and the face of insects is that part between the prothorax and the proboscis. - In military tactics, face means the side of a battalion when formed into a square. In fortification, the face of a bastion is formed of two sides extending from the sides of a salient angle;-face prolonged is that part of the line of defence which is between the angle of the shoulder and the curtain;-face of a place is the front, comprehended between the flanked angles of the two neighbouring bastions, composed of a curtain, two flanks, and two faces. -In gunnery, the face of a gun is the superficies of the metal at the extremity of the muzzle.-In mechanics, face is applied to the part of a cogged wheel which impels another wheel.-Face-guard is a wire-gauze mask to defend the face from accident in various chemical and manufacturing experiments.

Facet (Fr. facette a little face). The minute face of a diamond or other crystal.-In zoology, facets are the compound eyes of insects, composed of an innumerable assemblage of eyelets or lenses, called facet-eyes, each eyelet being a facet. In anatomy, small circumscribed portion of the surface of a bone, as the articular surface. In archi

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the nat projections between the flutings.

Fa'cial (Lat. facies the face), in parenology, the facial angle is an angle formed by the concurrence of two ideal lines, one perpendicular and the other horizontal. In anatomy, the facial bones are thirteen in number, exclusive of the teeth. The facial artery is a branch of the external carotid, which passes over the lower jaw, and distributes its ramifications to the face and palate. The facial nerve rises from the lower and lateral parts of the pons varolii, and quitting the cranium, enters the aquæductus Fallopii, and after supplying the muscles to the internal ear, &c., is distributed in three principal divisions of the face, termed the facial muscles. Fa'cies (Lat. the face), in anatomy, the anterior part of the skull, forming cavities of the orbits, nose, and mouth. -In zoology, the general aspect or external appearance of an animal as

it appears on a casual or first view. Facing, in architecture, that part of the work in a building seen by the spectator; more particularly that better sort of material used to mask an inferior. In carpentry, the wooden covering of the sides of windows, doors, &c., in the inside of rooms. In plaster-work, the last layer of fine plaster or stucco on walls. In the evolutions of military science, the different movements of the men to the right, left, &c.; also the name given to the lappets, cuffs, and collars of a regimental uniform. Factors, in the science of arithmetic, the multiplicand and the multiplier, or those numbers by the multiplication of which another is produced; thus 4 and 6 are the factors of 24, and in algebra a and y are the factors of ay.

Fac'ulæ (Lat. facula a little torch), in astronomy, a name applied to those spots on the surface of the sun which appear brighter than the rest; the darker spots are termed macula.

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