Ger'minal Membrane, in physiology, the membrane formed of cells, which immediately surrounds the ovum or egg after segmentation.

Gesneria'ceæ (from Gesner, of Zurich), in botany, a nat. order of corollifloral Exogens, consisting of herbs shrubs, of which Gesneria is the type and genus.

or

Geysers (Icel. roaring), certain fountains in Iceland, doubtless of volcanic origin, which spout forth boiling water. The jet of the great geyser is said to have been observed to rise 550 feet. One of the small geysers was observed by Mr. Henderson, in 1815, to project a stone to the height of 300 feet.

Giant's Causeway, in geology, a remarkable basaltic formation in the northern coast of the county of Antrim.

Gibbon, in zoology, the long-armed ape, and a general name given to all the species of the Hylobates. The largest of the group is black, and an inhabitant of Sumatra.

Gibbous (Lat. gibbosus), in astronomy, an epithet applied to the enlightened portion of the moon when more than half full, when the dark part appears falcated, or horned, and the light part convex.-In botany, the term is applied to leaves, petals, &c., when irregularly swelled on one side, or both, as the corolla of the Foxglove. -In natural history, gibbosus forms a prefix to the various compounds signifying bunch-like; as, gibbiflorus, having gibbous flowers; gibbipennis, having the elytra swelled out, oval, and globular gibbirostris, having a beak or snout of a protuberant shape; gibbifolius, having the leaves of a boss-like form.

Gibbsite, a white-greenish mineral found in Massachusetts, which occurs in stalactitial masses, and consists of alumina, water, silica, and peroxide of iron: sp. gr. 2.4.

Gie'seckite (from Sir C. Giesecke, its discoverer), a brownish crystallized mineral found in Greenland, consisting of silica, alumina, magnesia, protoxide of iron, protoxide of manganese, potash, and volatile matter: sp. gr. 2.83.

Gilbertite (from Davies Gilbert), a laminated whitish mineral, composed of plates lying irregularly on each other; constituents, silica, alumina, lime, magnesia, protoxide of iron, and water: sp. gr. 2'64

Gilliesia'ceæ (from Dr. Gillies), a nat. order of liliaceous plants, of which Gilliesia is the genus.

Gills (Swed. gel), the apertures for

breathing in fishes, consisting of car. tilaginous or bony arches attached to the bones of the head. The water has admission by the opening of the gills, and acts upon the blood as it circulates in the fibrils.

Gimbals, or Gimbols (Lat. gemellus a pair), in navigation, brass rings used in suspending the mariner's compass, by means of which the card is kept in a horizontal position, notwithstanding the motion of the vessel.

Gim'bleting, in navigation, a term denoting the turning of an anchor round by the stock, so that the motion resembles the turning of a gimblet. Gin (Fr.), in mechanical science, a term applied to different machines for raising heavy weights, driving piles, cleaning cotton, &c. Ginning is the operation by which the seeds of cotton are separated from the filaments by means of the apparatus called a cotton gin.

Girth, the circumference of a body. In measuring a tree, the term is used as the fourth part of the circumference, on account of the use made of it. The square of the fourth part is considered, in this case, as equal to the area of the section of the tree; which square, therefore, multiplied by the length of the tree, gives the solid

contents.

Gismondine (in honour of the mineralogist Gismondi), a mineral occurring at Capo de Bove, near Rome, in white translucent crystals, consisting of silica, alumina, lime, magnesia, oxide of iron, and oxide of manganese: sp. gr. 2.16.

Giusto (Ital.), in music, a term signifying that the movement before which it is written is to be performed in a steady, equal, and just time.Busby.

Gla'cier, pl. Gla'ciers (Fr. from Lat. glacies ice), in physicology, a term applied to a vast accumulation of ice and snow, found in the valleys and slopes of lofty mountains; the Alpine glaciers occupying a space of 1,484 square miles, and the vertical thickness ranging from 100 to 600 feet.Glacialist, an adherent to the glacial theory of geologists.

Glacis (Fr.), in fortification, a sloping bank of earth, extending from the parapet of a counterscarp to the level country.

Gland (Lat. glans, glandis an acorn), in anatomy, an organ of the body in which secretion is carried on, and which consists of a congeries of bloodvessels, nerves, and absorbents. Glands are divided into three principal classes:-1. The absorbent glands, which form a part of the absorbent system; -2. The sernent glands, whose office is to separate the various secretory and excretory fluids of the blood; 3. Vascular glands, consisting of a congeries of arteries and veins, but without any opening internally. Glans penis is the vascular body which forms the apex of the penis. In botany, a gland is any superficial callosity.--Lenticular glands are brown oval spots observed on the bark of many plants, especially willows, indicating points from which the roots will appear, if the branch be placed in circumstances favourable for their production.

Glanders, in farriery, a distemper of the glands in horses, in which corrupt matter runs from the nose.

Glass (Sax. glaes), in the arts, a transparent, impermeable, brittle substance, formed by fusing sand with fixed alkalies; that which is made of glass.-Glass-house is a manufactory in which silex or flint dust and fixed alkalies are subjected in furnaces to such an amount of heat as to render them fluid, which, when cold, constitute glass. Glasses, spectacles. Glau'berite, a crystallized mineral which occurs in rock salt, consisting of sulphate of soda and sulphate of lime: sp. gr. 2.80; Η = 2.5.

Glauber Salt (from John Glauber, a German chemist), in chemistry, a native sulphate of soda, a substance which occurs as a mineral body in a state of efflorescence, the primary form of the crystal being an oblique prism. It is found in the salt mines of Germany, Switzerland, and France:

sp. gr. 1'47.

Glau'colite (Gr. blue stone), in mineralogy, a silicate of alumina and lime of a greenish-blue colour, consisting of silica, alumina, lime, potash, soda, and magnesia: sp. gr. 2.7-3.2.

Glauco'ma (Gr.), in pathology, a disease of the eyes, giving a bluish-green colour to the vitreous humour.

Glau'conite (Gr. glaukos sea-green), in geology, an argillaceous marl, sometimes containing a mixture of greensand.

Glaucop'inæ (Gr. blue-eyed), in ornithology, a sub-family of the Corvidæ (the Wattle Crows), of which the Glaucopis is the type.

Glaucus (Gr. sea-green), a genus of nudibranchiate Mollusca, which constitutes the type of a family, the Glaucidæ, which are marine, gelatinous, and elongated.

Glazing, in painting, a term applied to transparent or semi-transparent co

lours passed thinly over other colours to modify their effect. Gleichenia'ceæ, in botany, a tribe of Ferns, of which the Gleichenia is the type; order Polypodiaceæ. Glenoid (Gr. glene a hollow, and eidos resemblance), in anatomy, the name of a bone or part having a shallow cavity, as the socket of the shoulder joint.

Gliding, in music, a term applied by flute-players to the action of sliding the finger from off the hole it has been employed in stopping, by which the ear is imperceptibly led to the succeeding note.-Busby.

Globe (Lat. globus), a spherical solid body; the terraqueous ball; the earth, or world; an artificial sphere made of metal, plaster, paper, &c., on the surface of which a map of the earth, or of the celestial constellations, is delineated, the one being called the terrestrial, the other the celestial globe. Globular projection is a kind of map in which the eye is supposed to be distant from the globe, represented in whole or in part by onehalf of the chord of an arc of o0°. -In navigation, globular sailing is the sailing from one place to another over the arc of a great circle, or the shortest distance between two places.

Globule (Lat. globulus a little globe), a small particle of matter of a spherical form. In physiology, the small microscopic particles of blood which float in a transparent serum. Glob'uline, in botany, a green globule lying among the cells of cellular tissue, first pointed out by Turpin, a French phytotomist. The term is also applied to an albuminous compound existing with hæmatosine in the globules of the blood.

Glossan'thrax (Gr. glossa the tongue, and anthrax a carbuncle), a form of anthrax, or blain, to which horses and cattle are subject, characterized by the development of malignant carbuncle in the mouth, and especially on the tongue.

Glossi'tis (Gr.), in pathology, inflammation of the tongue. Glos'socele (Gr.), protrusion of the tongue.

Glosso-epiglottic (Gr. glossa and epiglottis), an epithet applied to the muscles which pass from the tongue to the epiglottis.

Glossog'raphy, Glossology (Gr.), in anatomy, a description of, or discourse on, the tongue. Gloťtalite, a whitish vitreous mineral, discovered in the trap formation near Port Glasgow, consisting of silica,

lime, alumina, peroxide of iron, and water: sp. gr. 2.18.

Glucic Acid, an acid obtained from the solution of grape sugar saturated with baryta and lime.

Gluci'na, or Glucine (Gr.glykys sweet), a white earth or powder found in the beryl and emerald.

Glucin'ium, Gluci'num, or Glycium, the metallic base of glucina. Glue (Lat. gluten), a cement made by boiling some animal substance to a jelly.

Glu'males, in botany, an extensive class of endogenous plants, given by Lindley to his Glumal alliance. It comprises the_orders Graminaceæ, Cyperaceæ, Desvauxiaceæ, Restiaceæ, and Eriocaulaceæ.

Glume (Lat. gluma), in botany, one of the bracts of grasses; the calyx and corolla of corn and grasses; the husk or chaff of grain.

Gluten (Lat.), a viscid elastic substance found in wheat and other grains. Gluteus (Gr. gloutos the buttocks), in anatomy, the name of certain large muscles on which we sit; hence we have the term gluteal applied to the posterior iliac artery, to the lymphatics, which have the same distribution as that artery, and to a nerve distributed to the gluteal muscles. Glycerine (Gr.), a sweet substance extracted from fatty materials. Glyph (Gr. glypho to carve), in architecture, a vertically-sunken channel; a channel in a Doric frieze.

Glyph'ograph (Gr. glypho, and graphe writing), an engraved plate formed in relief by the electrotype process. -Glyphographer is an engraver or worker in glyphography.

Glyphog'raphy, or Galvan'oglyphy (Gr. glypho), in the arts, a process for producing engravings in relief at a much less cost than wood engravings, and with all the convenience of printing with letter-press. A drawing is etched on a zinc plate coated with varnish, as in the ordinary process of etching. Several coats of ink are spread over the plate by a small composition roller, which are only deposited on those parts where the varnish has not been cut through by the graver. When the incisions are thus rendered deep enough, the plate is placed in connection with a galvanic battery, and another plate is formed from the deposition of sulphate of copper, or blue vitriol, in which the hollows of the engraving are produced in reliet. -Suppt. to Craig's Dicty.

Glyptics (Gr.), the art of engraving figures on precious stones.

Clyptography (Gr. glypho, and graphe description), a description of the art of engraving upon gems. Glyptothe'ca (Gr. glypho, and theke a deposit), a building or room for the preservation of works of sculpture. Gmel'inite, a reddish-white mineral (the Hydrolite), consisting of soda, silica, alumina, lime, and water: sp. gr. 2.1.

Gnathi'tis (Gr.), inflammation of the lower jaw or cheek. Gneiss (Germ.), in geology, a stratified primary rock, composed of the same materials as granite; a species of granite of lamellar or slaty texture. Gneta'ceæ, in botany, a nat. order of Gymnogens (Joint Firs), consisting of small trees or shrubs. Gnomiometrical (Gr. gnomon an index, and metron a measure), in optics, measuring the angles of crystals, strata, &c., by reflection. Gnomon (Gr. an index), the hand, style, or pin of a dial; an apparatus for ascertaining astronomical altitudes. Gnomon of a globe, the index of the hour circle.

Gnomon'ics (Gr.), the art of constructing dials to show the hour of the day by the shadow of a gnomon.-Gnomonology is a treatise on dialling Go'bidæ (Lat.), a family of malacopterygious fishes, of which the Gobius, or Gudgeon, is the type. Gobiana is a sub-family or division of the Gobies. Godfrey's Cordial, in pharmacy, a kind of soothing syrup, composed of sassafras, caraway, coriander, and anise seeds infused in water, with tincture of opium and treacle added. Godroon (Fr.), in architecture, an inverted fluting, bending, or cabling, used in various ornaments and members.

Go'ethite, a German mineral of a brownish colour. Its constituents are peroxide of iron, oxide of manganese, and water.

Goggles (Welsh gogeln), in surgery, optical instruments for curing squinting. They are short conical tubes, with a thin plate of ivory fixed in tubes near their anterior extremities. Through the centre of each of these plates is a small circular hole for the transmission of the rays of light.-Goggles are also blinds for horses that are apt to take fright.

Goître (Fr.), a tumour on the throat; the bronchocele.

Gold (Sax.), a precious metal, of a bright yellow colour and of the sp. gr.

193; it is the most valuable and the most ductile of all the metals, and is used by all civilized nations as a standard of value. It occurs in regular veins in primary rocks; but the greatest quantity is obtained from alluvial soils, and in beds and sands of rivers. It is so malleable that it may be beaten into a leaf 280,000th of an inch in thickness, and so ductile that a single grain may be drawn into 500 feet of wire. Gold unites with most other metals, and with sulphur, ammonia, &c. It fuses at 2016°. Its equivalent is 1992; symbol, Au.-Standard gold is an alloy of 11 parts of pure gold and I of copper; its sp. gr. is 17.157. 1 lb. troy produces 46.71 sovereigns.Gold amalgam is a yellowish-white mineral, a mixture of gold and quicksilver; chiefly found in California.Gold-beating is a process by which the gold is brought to a state of extremely thin leaves, much used in the arts, and in various kinds of gilding. - Goldbeaters' skin is an extremely fine membrane between which goldbeaters lay the leaves of their metal while they beat it.Gold fields are the auriferous deposits and diggings in Australia, Ca-lifornia, and other localities.-Gold foil is thin sheets of gold, used by dentists and others. Gold size, a glue of a golden colour, a thin tenacious varnish used by gilders.

Golden, made or consisting of gold; a term applied to anything of acknowledged value; as, Golden number, in chronology, is the number reckoned from 1 to 19, showing what year in the lunar cycle any given year is.Golden rule, in arithmetic, the rule of three, so called from its great utility in arithmetical science. Golden pheasant is one of the most magnificent birds seen in our aviaries. It is the Phasianus picus of Linnæus. Goniom'etry (Gr. gonia an angle, and metron a measure), in mechanical science, the art or method o. measuring angles.-Goniometer is an instrument used in measuring them, particularly those formed by the facets of mineral crystals. It consists of a brass circle graduated on the edge, and furnished with a vernier, by which the divisions may be read to a minute.

Gon'ocele (Gr. gone semen, and kele hernia), in pathology, a tumefaction of the spermatic cord.

Gonorrhea (Gr.gone, and rheo to flow), in pathology, a morbid running of venereal taint.

Gorge (Fr.), in fortification, the entrance

of a bastion, or other outwork, consisting of the distance or space between the extremities of the two faces, as between the faces of a halfmoon, redoubt, or bastion. In architecture, a cavetto or concave moulding, the narrowest part of the Tuscan and Doric capitals, between the astragal, above the shaft of the pillar, and the annulets.

Gorget (Fr. gorgette), in surgery, an instrument used in the operation of lithotomy.

Gossan, in mining, a term applied to the oxide of iron and quartz, an ochreous mineral substance, which frequently occurs in mineral lodes at shallow depths.

Gossypium (Gr. from Arab. goz a soft substance), in botany, a most important genus of plants (the Cotton tree), from the capsules of which is produced the down used in the manufacture of cotton yarns and cloths. Gothic Architecture, a style in which pointed arches of greater height than breadth, and a profusion of ornaments, in imitation of leaves and flowers, are the principal characteristics. It began to flourish during the middle ages, and is still continued in our ecclesiastical architecture. Goulard, in pharmacy, an extract of sugar of lead, used for inflammations.

Gov'ernor, in mechanical science, a contrivance for inaintaining uniform

velocity with varying resistance. Gowan, in geology decomposed granite.

Gowt, or Go' yut, in engineering, a sluice used in embankments for letting out

water.

Grace Note, in music, any note added as an ornamental flourish.

Graddo (It.), in music, a word applied to the notes moving by conjoint intervals.

Gradient (Lat. gradus a step, descent), the proportionate ascent or descent of the several planes on a railroad; thus, an inclined plane 2 miles in length, with a total fall of 18 feet, is described as having a gradient of 9 feet per mile.

Graduate (Ital. graduare to step for. ward), in literature and the arts, one who has received a degree in a college or university, or from some professional incorporated society. -Graduation, regular progression; act of graduating.

Gradua'tor (Lat. gradus), in physics, a contrivance for accelerating spontaneous evaporation; also an instrument for dividing any right line or curve into equal portions.

Graduction, in astronomy, the division of circular arcs into degrees, minutes, &c.

Grafting (Fr. greffe), in the science of horticulture, the art or process of inserting the scion of one tree into the stock of another, so as to make it produce fruit of the same kind and quality as that of the tree from which the graft was taken.

Graining, in painting, the art of imitating the grain and colours of woods and marbles by means of either oil or water colours.

Grains of Paradise, the seeds of a species of Amomum, spice, or pepper. Grakles, in ornithology a name applied to the sub-family Lamprotortinæ; ram. Corvidæ.

Grallato'res, or Grallæ (Lat. grallæ stilts), in ornithology, the fourth order of birds, the Waders. The families of this order are the Ardeada, or Herons; the Charadriada, or Plovers; the Scolopacida, or Sandpipers and Snipes; the Rallide, or Rails; and the Tantalide, or Ibices. It comprises all such species as live both on the land and the sea, and to which the one element is as essential as the other.

Gramin'ese (Lat. gramen grass), in botany, an order of Endogens (the Grasses), consisting of evergreen herbs, with narrow and undivided leaves.

Graminiv'orous (Lat. gramen, and voro to devour), an epithet applied to those animals which subsist entirely on vegetable food, while those which live on flesh alone are called carnivorous. In natural history, the following words occur, as designating species: Graminous, grass-like; graminicolus, growing among dry stubble, or in corn-fields; graminifolius, having grass-like leaves; graminiform, resembling

grass.

Grammar (Gr. gramma, a letter), the art of speaking and writing a language correctly; the science which has for its object the laws regulating human language; the elementary parts of learning, or of any science. Grammar is divided into four parts, Orthography, Etymology, Syntax, and Prosody.

Gram'matite, in mineralogy, a variety of hornblende, found in the primary rocks.

Gramme (Fr.), a French weight equal to 15 444 grains.

Grampus, a fierce and voracious Cetacean, the Delphinus orca, which sometimes attains the length of 25 feet.

Gran'atite (Lat. granum a grain), a precious stone, a reddish-brown mineral, occurring in primary rocks in many parts of Scotland and America, consisting of alumina, silica, oxide of iron, oxide of manganese, and lime. Gran Gusto (Ital.), in painting, a term expressive of something very extraordinary in a picture, and calculated to surprise. In music, an expression applied to any high-wrought composition. With grandis (grand), the following compounds occur in natural history to designate species:Grandiflorus, large-flowered; grandifolius, large-leaved; grandidentatus, furnished with large teeth. Granite (Fr. from Lat. granum a grain), in mineralogy, a hard and durable rock or stone; a crystalline aggregate of quartz, felspar, and mica. Granite is a plutonic rock that seems to have been consolidated from a state of fusion at a considerable depth beneath the surface of the earth, and to have been denuded and raised to the surface during the lapse of time, so as now to form the summits of lofty mountains. Granite is said to be porphyritic when large crystals of felspar are disseminated through the mass; sienitic, when hornblende supplies the place of mica; chloritic, when chlorite supplies the place of mica, &c.-Granitic aggregate is a granular compound, consisting of two or more simple minerals, among which only one of the essential ingredients of granite is present. Among the granitic aggregates may be enumerated combinations of quartz and hornblende, - quartz and actinolite, - felspar and schorl,-mica and hornblende, -quartz, hornblende, and garnet, -quartz, hornblende, and epidote, &c.-Granitine is an aggregate of three mineral constituents, one or more differing from those which compose granite.-Graphic granite is a variety of granite composed of felspar and quartz, ranged as to produce an imperfect laminar structure. When a section of graphic granite is made at right angles to the alternations of the constituent minerals, broken lines, resembling Hebrew characters, present themselves; hence its derivation. Graniv'oræ (Lat. grain-eaters), an order of Insessorial birds which feed on grains.

SO

ar

Gran'ular Limestone, in mineralogy, a variety of limestone, consisting of small grains or minute crystals. It is of different colours; and the white variety is used as statuary marble.