Granula'tion (Lat.), in pathology, firm, rounded, or ovoid, glistening, semitransparent tumours, resembling in figure and volume a millet-seed or pea. In chemistry, an operation by which metallic substances are reduced into small grains for the purpose of facilitating their combination with other substances.

Granu'liform, in mineralogy, having an irregular granular structure. Gran'ulite (Lat. granum, and Gr. lithos a stone), in mineralogy, a rock consisting of felspar and quartz.

Graphic Microscope, an instrument for the purpose of depicting, on the principle of reflection, the objects represented by the microscope.

Graphic Tellurium, or Graphic Gold, a mineral of a steel-grey colour, approaching to tin-white. Its constituents are tellurium, gold, and silver. Graphiology, (Gr. grapho to write, and logos a discourse), a treatise on written characters.

Graphite (Gr. grapho), a form of mineral carbon; the substance of which pencils are made.

Graph'olite (Gr.), a species of slate proper for writing on.

Graphom'eter (Gr.), a surveying instrument; a graduated semicircle. Its use is to observe any angle, the vertex of which is at the centre of the instrument in any plane, and to find how many degrees it contains.

Grap'tolite (Gr. graptos painted, and lithos a stone), a genus of fossil Zoophytes or Protozoa.

Graptol'ithus (Gr.), a stone havingt the appearance of drawings, maps, ruins, &c. Grass. (See Graminea.)

Gravel, in medicine, a disease occasioned by the concretion of calculi in the kidneys and bladder.-In mineralogy, small stones, generally deposited on the beds of rivers or the seashore, from the consolidation of which, in former periods, the conglomerates of the various formations take place. Gravim'eter (Lat. gravitas gravity, and metor to measure), an instrument for ascertaining the specific gravity of bodies.

Gravita'tion (Lat.), the act of tending to the centre; the mutual tendency which all bodies in nature have to approach each other. (See Gravity.) Gravity. Specific gravity is the weight of the matter of any body, compared with the weight of an equal bulk of pure water, taken as a standard. Thus, if a body when immersed in fluid loses just as much of its weight as is equal to the weight of a given volume of the fluid, and the weight lost in water be made the divisor of

the weight in air, the quotient gives the specific gravity. The instrument used is called the hydrostatic balance. One cubic foot of rain-water weighs exactly 1,000 Ozs. avoirdupois; hence the relative weight of other bodies is easily referred to this standard; and hence gold, when hammered, weighs 19.362, which is its specific gravity. Centre of gravity is that point at which all the weight of a mass might be collected without disturbing the equilibrium of any system of which the mass forms a part. When a body is suspended by a string, and allowed to find its position of rest, the centre of gravity is in the line of the string. Graystone. (See Greystone.) Graywacke (Germ. grey stone), in mineralogy, a term applied to some of the lowest secondary strata; a kind of arenaceous rock.

Grazioso (Ital.), in music, with elegance and grace.

Great Sixth, in music, a term applied to the chord of the fifth and sixth, when the fifth is perfect, and the sixth major. Busby.

Greek Fire, an artificial fire which burnt under water, and was formerly used in war, especially between the Christians and the Saracens. It was either poured from the ramparts in large boilers, or launched in red-hot balls of stone and iron, or darted in arrows and javelins twisted round with flax and tow saturated with it; sometimes it was blown through long tubes of copper placed on the prow of a galley or fireship. The old French writer Joinville says:-"It sometimes came flying through the air like a winged long-tailed dragon, about the thickness of a hogshead, with a report of thunder, and the velocity of lightning, dispelling the darkness of the night by its deadly illumination."

Green, a term which forms a prefix to many important words connected with science and art.-Green earth is a variety of chloritic earth which occurs in the vesicular cavities of some amygdaloids: it constitutes the mountain green of painters. -Brunswick green is made by saturating cold water with muriated ammonia, and adding three times as much copper clippings as ammonia. The muriate of ammonia is decomposed by the copper, which is itself corroded and converted into a green oxide. Green vitriol, the sulphate of iron, consisting of I atom of the protoxide of iron, and I atom of sulphuric acid. The crystals contain 7 atoms of water.-Sheele's green is an arseniate of copper. Mineral green is a subcarbonate of copper. Green'obite, a mineral of a deep rosered colour, consisting of silica, oxide of titanium, lime, and protoxide of manganese: sp. gr. 3'44.

Green'ockite (in honour of Lord Greenock), a hard, crystallized mineral, a native sulphate of cadmium, consisting of sulphur 22.56, and cadmium 77 30: sp. gr. 484.

Greensand, in geology, arenaceous beds of the tertiary formation of the cretaceous system, so termed from its abounding with small grains of chlorite.

Greenstone, in mineralogy, a variety of trap; an igneous rock in which felspar is combined with augite or hornblende. It sometimes occurs of great extent and thickness.

Gregorian Chant is choral music according to eight church modes arranged by Pope Gregory I.

Grego'rian Telescope, a reflecting telescope invented by Professor Gregory, of St. Andrew's.

Grenade, in military science, a hollow globe or ball of iron filled with gunpowder for explosion. Gren'atite, a mineral; the Staurolite. Gressu'ra (Lat. gradior to proceed), in anatomy, the perinæum, which proceeds from the anus to the pudendum. Greystone, in geology, a term applied to certain volcanic rocks, composed of felspar, augite, or iron and hornblende.

Groin (Goth. grein), in architecture, the line formed by the intersection of two arches which cross each other at any angle. Groined ceiling is a ceiling formed by three or more curved surfaces, so that every two may make a groin, all the groins terminating at one extremity in a common point.In engineering, groin is a wooden breakwater to retain sand or mud thrown up by the tide.

Grossulaceae (Lat.), in botany, a nat. order of exogenous plants, of which the Grossularia, or Gooseberry, is the type; it consists of only one genus, Ribes.

Grossula'ria (Lat.), in mineralogy, a green garnet. In botany, a species of gooseberry. Grossularite, a species of green-coloured garnet, consisting of silica, alumina, lime, oxide of iron, and oxide of manganese: sp. gr.

the first layer of colour on which the figures or other objects are painted. -In sculpture, it is the surface from which, in relievo, the figures rise.In architecture, it is used to denote the face of the scenery or country round a building. - Ground plan, the plan of the story of a house level with the surface of the ground, or a few steps above it. - Ground plates are the outermost pieces of timber which lie near the ground.

Gryphæ'a (Lat. gryps a griffin), in fossilology, a genus of shells of the Oyster family.

Gryphite, in conchology, a fossil bivalve shell.

Grypho'sis (Gr. grypos incurved), in physiology, a growing inwards of the nails.

Guérite (Fr.), in fortification, a small tower for holding a sentinel. Guilloche (Fr.), in architecture, an or nament in the form of two or more bands twisting over each other, so as to repeat the same figure, in a continued series, by the spiral returning of the bands.

Guinea, an English denomination of money, of the value of 21S., first coined of gold brought from Guinea; now disused; but the word is of frequent occurrence in botany and zoology. Guinea-corn, a vegetable growing on the coast of Africa. Guinea-deer, a small quadruped.-Guinea-fowl, a fowl from the coast of Guinea.-Guinea-grass, a valuable plant or grass.-Guineahen, a domestic African fowl.Guinea-pepper, the seeds of Amomum, from Africa. Guinea-pig, a small Brazilian animal.-Guineawheat, the plant Zea mays.-Guineaworm, the Filaria Medinensis of Gmelin-a worm which proves a considerable pest in warm countries, by insinuating itself under the skin. Guitar (Span.), a stringed musical instrument much used in Spain and Italy.

Gules (Fr.), in heraldry, red, represented in engravings by straight perpendicular lines.

Gum (Lat.), a concrete vegetable substance, soluble in water, which exudes from certain trees, and hardens on the surface. There is a great variety of gums, which are of vast utility in the different branches of art and science. The principal of them are here enumerated in alphabetical order:-Gum ammoniacum, the produce of the Persian tree Dorema ammoniacum;-Gum animé, the resinous produce of the West Indian tree Hymenaa courbaril;-Gumara

bic, the concrete juice which exudes from several species of Acacia;Gum copal, the resinous produce of the Mexican tree Elaphrium excelsum;-Gum cistus, a secretion of several species of plants of the genus Cistus;-Gum elastic (see Caoutchouc);-Gum-elemi tree, a tall tree, full of resinous fragrant juice;Gum galbanum, the produce of the Syrian plant Galbanum officinale ;Gum juniper, a concreted resin which exudes in white tears from the Juniperus communis;-Gum lac, the resinous produce of the East Indian tree Butea frondosa; also the resinous produce of an insect which deposits its eggs on the branches of a tree called bihar;-Gum of starch, the soluble substance of fecula;Gum resin, the concrete juice of certain plants, partly soluble in water and partly in alcohol, consisting of aloes, asafœtida, bdellium, galbanum, gamboge, guaiac, myrrh, olibanum, opoponax, sacacolla, scammony, and styrax;-Gum senegal, the produce of the tree Acacia Senegal;-Gum tragacanth, the produce of the plant Astragalus tragacantha; -Gum tree is the popular name of the Black Gum, of the genus Nyssa, one of the largest trees of the Southern States of America;-Gumwater is a distillation from gum, especially from gum arabic.

Gumma (Lat.), in pathology, a soft tumour resembling gum.

Gun (Welsh gwn), in military science, a general term for all species of firearms, as muskets, rifles, carbines, ordnances, &c., the principal of which are the Muzzle-loading and Breechloading guns, the latter comprehending the Needle Gun (which see). -Gunpowder is a mixture of 5 parts of nitre, I of sulphur, and 5 of charcoal, finely powdered and very accurately blended.-Gun-cotton is a preparation of cotton by steeping it in nitric or nitro-sulphuric acid, and afterwards washing it, by which it acquires the explosive properties of gunpowder.-Gun-barrel, the metallic tube of a gun.-Gun-boat, a boat for carrying cannon. Gun-lock, the lock of a gun.-Gun-metal, an alloy of copper and tin.

Gunter's Chain, in surveying, a chain for measuring land, so called from Gunter, the inventor; its length is 66 feet, and it is divided into 100 links, of 792 inches each.-Gunter's line is a logarithmic line engraved on scales, sectors, &c.-Gunter's quadrant is an astronomical instrument for finding the hour of the day,

&c.-Gunter's scale is a scale having various lines and angles engraved on it, and used for resolving questions in navigation.

Gustoso (Ital. tastefully), in music, a term signifying that the movement before which it is written is to be performed in a finished style.

Gutta, pl. Gutte (Lat. a drop), a term applied to medical prescriptions, written gt. or pl. gtt.; as, gutta anodyna, the anodyne drop, a solution of acetate of morphia; gutta myra, the black or Lancashire drop.-In pathology, gutta opaca is cataract;Gutta serena, amaurosis; -Gutta rosacea, rosy drop. In architecture, Gutte are small ornaments resembling drops, used in the Doric entablature on the under side of the mutules of the cornice, and beneath the tænia of the architrave under the triglyphs.

Guttifer (Lat. gutta), a plant yielding gum or resin. Guttifera'ceæ (Lat. gutta, and fero to bear), a nat. order of exogenous plants which yield resinous juices. Guttural (Lat. guttur the throat), in music, an epithet given to that tone and style of intonation which the Italians call "singing in the throat." Gymnasium (Gr. gymnos naked), formerly, a place for athletic exercises; at present, any place of exercise.Gymnastics is the science of performing gymnastic exercises; the gymnastic art.

Gymnodon'tes (Gr. gymnos, and odontes teeth), in ichthyology, the name of a family of malacopterygious fishes, of the order Plectognathes. Gymno'tus (Gr. gymnos, and notos the back), a genus of apodal fishes, with eel-shaped bodies, of which the Electricus has the remarkable property of communicating an electric shock to the person touching it; fam. Sternarchidæ.

Gynan'dria (Gr. gyne a female, and andres men), a class of plants (the twentieth class of Linnæus) which have their stamens and pistils consolidated into a single body.

Gypsum (Gr. gypsos), native sulphate of lime, commonly known as plaster of Paris, extensively used in the plastic arts. It occurs in the new red sandstone of England and Germany, and in the tertiary rocks of the neighbourhood of Paris, &c. It consists of I atom of sulphuric acid, I of lime, and 2 of water: sp. gr.

around an axis or a point of suspension (Brande). Centre of gyration is a point at any such distance from the axis, that the moment of inertia would not be altered

Haarkies (Germ.), in mineralogy, a native sulphuret of nickel; capillary pyrites in very delicate acicular crystals.

Habitat (Lat. habito to inhabit), in zoology and physiology, the natural locality or abode of an animal or plant.

Hackberry, in botany, the popular name of the Celtis occidentalis, an ornamental tree of N. America, the wood of which is hard and closegrained.

Hack'ia, in botany, a hard and valuable kind of wood, growing in Demerara, and known as Lignum vita.

Hæma-, Hæmo-, (Gr. haima blood), in physiology, a prefix to many compound words connected with or signifying blood; as, as, Hamadynamometer, an instrument for measuring the force of the flow of blood in the arterial vessels; -Hamapophysis, a term applied to the parts projecting from a vertebra; -Hæmastatics, that department of physiology which treats of the laws that regulate the movements of the blood in the vessels of the animal system;-Hematemesis, the vomiting of blood from the stomach; -Hamatine, or Hæmatosine, the colouring matter of the blood;-Hematocele, an effusion of blood into the scrotum;Hæmatocrya, a term applied to coldblooded vertebrated animals;-Hamatoid, of the nature or appearance of blood;-Hamatosis, hæmorrhage or flux of blood; - Hamatotherma, warm-blooded vertebrated animals; -Hamoptysis, disease of spitting blood;-Hemostatic, arresting the flow of blood.

Hæmal (Gr.), in anatomy, relating to blood; an epithet applied to the arch proceeding from a vertebra which encloses and protects the organs of circulation.

Hæ'matite (Gr. haima), in mineralogy, native oxide of iron. Hæmatology (Gr.), a treatise on the nature and properties of blood. Hæmatom'phalum (Gr. haima, and omphalos the navel), in pathology, hernia of the navel, with a bloody serum contained in the sac, or exhibiting on its surface many varicose veins.

if the whole mass were collected at that point.

Gyroscope (Gr. gyros, and skopeo to view), an instrument to illustrate the principles of circular motion.

Hæmatosco'pia (Gr. blood-inspection), an examination of the qualities of the blood when drawn from a vein. Hæmatox'yline (Gr.), the colouring matter of the wood of the Hematoxylon Campeachianum, or logwood, a well-known dye-stuff.

Hæmaturia (Gr. haima, and ourion urine), in pathology, the voiding of bloody urine.

Hæmodora'ceæ (Gr. haima blood, from its red-coloured roots), a nat. order of plants, allied to the Narcissus tribe, of which Hæmodorum is the genus.

Hæmoptysis (Gr. haima, and ptyo to spit), in pathology, the spitting or coughing up of blood, produced sometimes by an over-fulness of blood in vessels of the lungs, or by rupture in consequence of ulceration. Haidin'gerite, in mineralogy, an arseniate of lime, white and transparent, with a vitreous lustre: sp. gr. 2.84. Hair, in botany, long expansions of the cuticle, intended to protect the surface of a plant.-Hair-grass is the common name of the grass Aira, of which there are numerous species.Hair-salt, in mineralogy, is the native sulphate of magnesia. Half-moon, in fortification, an outwork composed of two faces forming a salient angle, whose gorge is in the form of a crescent or half-moon. Half-pike, in military and naval matters, a defensive weapon, so called from its being shorter than the ordinary pike.

Haliotidæ (Gr. als the sea, and otis of the ear), a family of the gasteropodous Mollusca, of which the Haliotis, or Ear-shell, is the type. Hal'itus (Lat. a breathing), the odour or vapours which escape from blood. Halloylite, a mineral with a waxy lustre, whose constituents are silica, alumina, and water.

Halo, a luminous circle sometimes appearing round the heavenly bodies, but more especially the sun and moon. Hal'ogens (Gr. als salt, and gennao to produce), substances which, by combination with a metal, produce saline compounds, such as chlorine and

iodine.

Haloid (Gr. like salt), in chemistry, an

epithet applied to a class of chemical combinations composed of two elementary compounds, one or both of which are analogous in composition to sea-salt.

Halora'geæ (Gr. als the sea, and rax a berry), an order of exogenous plants, the Hippurids.

Hal'teres (Gr.), in entomology, two organs in the Diptera consisting of cylindrical filaments, terminating in a club extremity, one arising from each side of the thorax, in the situation of which the second pair of wings in the Diptera originate.

Hamamelid'eæ, in botany, a nat. order of umbelliferous Exogens, of which the Hamamelis, or Witch-hazel, is the type.

Hand (Sax.), in anatomy, the organ of prehension in man and the mammalia; it consists of-1. the carpus, or wrist, which is composed of eight bones, viz. the scaphoid, or boatshaped; the semilunar, or halfmoon; the cuneiform, or wedge-like; the pisiform, or pea-like; the trapesium, or four-sided; the trapezoid, like the former; the os magnum, or large bone; the unciform, or hooklike.-2. The metacarpus, or the four bones constituting the palm and back of the hand.-3. The digiti, or fingers, consisting of twelve bones, arranged in three phalanges, or rows.-4. The pollex, or thumb, consisting of three bones.

Harbour, in the art or science of glassblowing, a technical name for a large chest, to hold the mixed ingredients previous to their being put in the pot for fusion.

Hardness, a term of frequent use to express the qualities of particular minerals; and this can be done almost with scientific exactitude. Mineralogists have formed a scale which affords an approximation in estimating the hardness of minerals; and according to this, the degree of hardness is expressed in numbers, from the softness of Talc (1), to the hardness of Diamond (10); thus:1, Talc, white or greenish; 2, rocksalt, pure and cleavable; and gypsum, uncrystallized and semitranslucent; 3, calcareous spar, cleavable; 4, fluorspar, which cleaves perfectly; 5, apatite, the asparagus stone from Salzburg; 6, adularia; 7, rock-crystal, limpid and transparent; 8, topaz; opaz; 9, corundum, with smooth fractured faces; 10, diamond. Any mineral which neither scratches nor is scratched by any one of the substances above named is stated to possess the degree of hardness ex

pressed by the number opposite that mineral. Thus, supposing a body neither to scratch nor to be scratched by fluor-spar, its hardness is represented by 4; but if it should scratch fluor-spar, and not apatite, then its hardness is stated to be from 4 to 5. Har'maline, a peculiar substance discovered in the seeds of the plant Peganum harmula. It may be used as a yellow dye, and by oxidation be made to yield a magnificent red dyestuff. Formula, C24H13N2O. Harmo'nia, in astronomy, the name of one of the newly-discovered planets, first observed in 1856. In anatomy, a form of articulation in which the surfaces of bones are merely placed in opposition to each other, so as not to allow motion.

Harmon'icon, a peculiar form of musical glasses invented by Dr. Franklin, whence the notes are obtained by striking with a cork on pieces of glass, which differ in size, and are loosely suspended, so as to admit of vibrating sounds.

Harmon'ics, the doctrine or science of musical sounds.-Harmonic proportion is a series of quantities in which any three adjoining terms being taken, the difference between the first and second is to the difference between the second and third as the first is to the third.-Harmonic triad is the chord of a note, consisting of a third and perfect fifth.

Harmon'iphon (Gr.), a musical instrument played with keys like a piano

forte.

Harmonom'eter (Gr.), an instrument for measuring the harmonic relations of sounds.

Harmony, in music, the just adaptation of parts to each other, according to musical sounds; melody.

Har'motone (Gr. harmos a joint, and temno to divide), a white mineral, the Staurolite, or Cross-stone, the crystals of which intersect each other. The constituents are silica, alumina, lime, protoxide of iron, and water: sp. gr. 2.40; Η = 4.25. Harpal'ide (Gr. harpaleos greedy), in entomology, an extensive family of coleopterous insects, of which the Harpalus is the type. Hartall, orpiment, an oxide of arsenic, used as a yellow paint. Hartshorn, in pharmacy, the horn of the common stag, which obtains a place in the pharmacopeia because it contains less earthy matter and more gelatine than other bones;Spirit of hartshorn, a volatile spirit, obtained by the distillation of the horn of the hart (see Amn.onia);