Forma'tion (Lat.), in geology, any assemblage of rocks, alluvial deposits, or sedimentary strata referred to a common origin or period (Lyell). The term properly signifies a series of rocks, usually passing gradually into each other, and the whole being considered as belonging to a certain period of geological time. A geological formation may consist of rocks entirely dissimilar, as the coal, shale, ironstone, and sandstone of the coal formation; or the chalk, flints, and sands of the chalk formation. Formic Acid (Lat. formica an ant), in chemistry, an acid derived from ants -a sour liquid which they eject when irritated. It may be obtained artificially by distilling, in a large retort, a mixture of 2 parts of tartaric acid, 3 of peroxide of manganese, and 3 of sulphuric acid, diluted with 5 of water.-Formiate is a salt formed by the union of formic acid with a base. Formica'tion (Lat.), in pathology, a certain creeping sensation affecting the skin, like the crawling of ants. Formic'ida (Lat. formica an ant), in entomology, an extensive family of hymenopterous insects, of which the Formica is the type and genus.-Five species are enumerated as belonging to Britain, viz., the hill ant, F. rufa; the jet ant, F. fuliginosa; the red ant, F. rubra; the common yellow ant, F. flava; and the small black ant, F. fusca.

Formobenzo'ic Acid, in chemistry, an acid forming a white granular powder, prepared by dissolving bitter oil of almonds in water, adding hydrochloric acid, and evaporating in a gentle heat.

Formula (Lat.), a term of frequent application in the different sciences.-În chemistry, a concise mode of exhibiting by symbols the results of chemical changes (Brande); thus, the formula of common salt (chloride of sodium), is Na+ Ch, or NaCl.-In medicine, a prescription; the mode of preparing medicines (Hoblyn).--In mathematics, a theorem, or general rule or expression for solving certain particular cases of some problem; as,

ax-x2 is the formula or generic value of the ordinate to a circle whose diameter is d and absciss x (Craig). -Formule, in chemistry, is a hypothetical radicle, the formula of which is C2H; i.e. 2 atoms of carbon and I of hydrogen.

Fornix (Lat. an arch), in conchology, the excavated part of a shell beneath the umbo. In anatomy, a part of the corpus callosum of the brain, which,

when viewed in a particular direction, has something like the appearance of a Gothic arch. Forsterite, a mineral which forms small brilliant crystals, found at Vesuvius; so called in honour of Mr. Forster. Fort, or Fortress (Lat. fortis strong), in military science, a small fortified place, environed on all sides with a moat, rampart, and parapet.-A royal fort is a fortification having at least twenty-six fathoms for the line of defence.-Fortalice is the name of a small fortress, formerly reckoned in Scottish law as inter regalia. Forte (Ital.), in music, a direction to sing or play with force or tone. Fortifica'tion (Lat.), the science of military architecture; the art of constructing such works of defence as may best enable the besieged to withstand the attacks of an assailing force.

Fortu'na (Lat.), in astronomy, the name of one of the newly-discovered planets, first observed by Hind in 1852. Its mean distance from the sun is 233,810,000 miles, and the time of its periodical revolution three years and three hundred days.

Forzan'do (Ital.), in music, a word used to indicate that notes are to be boldly struck and continued.

Foss, Fossa, Fosse (Lat.), in fortification, a ditch or moat full of water. -In anatomy, an osseous cavity with perforation. In the human skeleton there are various fossæ; as, Fossa hyaloidea, the cup-like excavation of the vitreous humour in which the crystalline lens is embedded;-F. lacrymalis, a depression in the frontal bone for the reception of the lachrymal gland;-F. navicularis, the dilatation towards the extremity of the spongy portion of the urethra;-F. ovalis, the oval depression presented by the septum of the right auricle, &c.-Fosse-way, one of the great Roman roads through England, which extended from the coast of Lincolnshire to that of Devonshire. Fossil (Lat. fossilis, from fodio to dig), a substance dug out of the earth, as petrified plants, shells, bones, &c.; organic remains of animals and plants found in the different geological strata of the earth's crust.-Fossilization is the process of conversion into a fossil, or petrifaction.-Fossilology is the science of fossils, or a treatise on them.

Fosso'res (Lat. fossor a digger), in entomology, a group of insects which excavate cells for their eggs in wood or earth; the second family of Hymenoptera, which are armed

with a sting, and furnished with wings. Fougade, or Fougasse (Fr.), in fortification, a little well-like mine filled with combustibles to blow up a fort. Fount, Fountain (Lat. fons), the head or source of a river; an artificial spring.-Glass fountain is a pneumatic instrument, consisting of a glass vessel and a tube within it, for the purpose of showing the elasticity of the air. Fourchette (Fr.), in ornithology, the bone formed by the junction of the clavicles; commonly called the merry-thought. Fourneau (Fr.), in military engineering, the chamber of a mine in which the powder is lodged.

Fourth, in music, an interval enumerated among the discords. The minor

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lesser fourth consists of five semitones; but the fourth sharp, or greater, consists of six semitones.In anatomy, fourth pair of nerves is a term applied to the nervi pathetici.

Fovil'la (Lat. foveo to nourish), in botany, a fine substance emitted from the pollen of flowers.

Fowler's Solution, in chemistry, a solution of the arseniate of potassa, coloured and flavoured by the compound spirit of lavender. Fraches (Fr.), in glass-blowing, a name applied to the flat iron pans into which the glass vessels, already formed, are put into the lower oven over the working furnace. Fraction (Lat.), in arithmetic and algebra, a broken number which consists of a part or parts of any number considered as a unity. The parts of a unit or whole are expressed by two numbers with a line between them, as,; and, in decimal fractions, by a period placed before it, as '5, 8: the upper figure of a vulgar fraction is called its numerator, and the under its denominator. Fracture (Lat. fractura), in mineralogy, the uneven or irregular surface which a mineral exhibits when broken. When the surface is perfectly smooth, it is termed cleavage: fractures are earthy, granular, splintery, conchoidal, &c.-In surgery, fracture is a break in a bone, when crushed or broken by some external violence; a simple fracture is where a bone is broken only in one part; a compound fracture is when two bones contiguous to each other are broken; a complicated fracture is one attended with a train of symptoms, as a wound or ulcer.

Frænum, Fræ'nulum (I at. a bridle), in

anatomy, a membrane or string by which one organ is connected with another; as, Frænum epiglottides, the ligament which connects the epiglottis with the root of the tongue and os hyoides;-F. linguæ, a fold of the mucous membrane of the mouth which binds down the tongue;-F. preputii, a fold of integument connecting the prepuce with the glans penis.

Fraise (Fr.), in fortification, a range of horizontal stakes for the purposes of defence, consisting of pointed stakes six or seven feet long, driven horizontally or inclined into the intrenchments of a camp, half-moon, &c. Framboe'sia (Fr. framboise, a raspberry), in pathology, a contagious disease (the Yaws), which is epidemic in certain parts of Africa and the West India Islands.

Francoa'ces (from Dr. Franco, of Valentia), in botany, a nat. order of hypogynous Exogens, of which the Francoa, a plant of Chili, is the genus and type.

Frankenia cea (from Frankenius, professor of botany at Upsal), a nat. order of hypogynous Exogens, of which the Frankenia, or Sea-heath, is the type.

Frank'incense, a gum resin, used as a

perfume, which exudes from a species of fir; supposed to be the olibanum of commerce.

Frank'linite (from the celebrated Beni. Franklin), a mineral found in grains or granulated masses, associated with the red oxide of zinc and other minerals. It consists of peroxide of iron, oxide of zinc, and red oxide of manganese: sp. gr. 4'87.-Thomson. Frax'inin (Lat. fraxinus an ash), in chemistry, a neutral principle obtained from the ash tree, which has neither an acid nor alkaline reaction.

Freestone, a species of free-working sandstone or oolite, commonly used in building.

Freezing (Sax. frysan), in physics, the mutation of a fluid body into a solid state by the abstraction of heat.Freezing point is that point or degree of cold at which certain fluids begin to freeze, as indicated by Fahrenheit's thermometer, which is 32° above zero for water, and 40° below zero for quicksilver.-Freezing mixture is a preparation for congealing water or other fluids. Thus an equal mixture of snow or pounded ice and salt sinks the thermometer to 30°; equal parts of nitrate of ammonia and water make it sink to 46°; and muriate of lime 3 parts, and snow or

ice 2 parts, sink it to 80°, or, from the freezing point to 48° below zero. Freezing mixtures are also made by the rapid solution of salts, without the use of snow or ice.

Fresco (Ital. shadiness), in the arts, a method of painting on fresh plaster by which the colours sink in and become durable.

Fret, or Fretto (Swed. frata), in music, that stop of a musical instrument which causes or regulates the vibrations of the strings. In architecture, a kind of knot of two small fillets interlaced;-Fret-work, that kind of work which is adorned with frets, and sometimes used to fill up and enrich flat empty spaces, but principally in roofs fretted over with plaster-work.-In heraldry, a bearing composed of six bars crossed and variously interlaced.

Friction (Lat.), in therapeutics, the art of rubbing any part of the surface of the body with the hand or brush, or with oil or ointment.-In mechanics, the act of rubbing the surface of one body against that of another ;-Friction rollers are small cylinders fixed between the axis on which a pulley turns, and the pulley itself, the hollow axis of the latter being made larger in order to receive them ;-Friction balls, a mechanical contrivance for moving heavy weights round a centre, as in cutting a block of marble. Frieze (Fr.), in architecture, a large flat member, which separates the architrave from the cornice.-In the Doric order, the frieze is always ornamented with triglyphs and sculptures. In the Corinthian and Composite orders the frieze is variously decorated, according to the taste or skill of the architect. Fringil'lida (Lat.), in ornithology, a family of the Conirostres (the Finches), of which the Fringilla, or Chaffinch, is the type. This family includes the Linnets, Sparrows, Bullfinches, Goldfinches, Buntings, Larks, &c.;-Fringilline, is a sub-family of the Fringillidæ, comprehending the Ground-finches; - Fringillaceous, pertaining to the Finches." Frond (Lat. frons a leaf), in botany, a green, leafy branch; the leaf of a fern or palm. The herbaceous parts of flowerless plants are called fronds. -In surgery, a bandage chiefly employed in wounds and diseases of the nose and chin, or in fracture of the jaw. Frondescence is the precise month and season of the year when each species unfolds its leaves.Frondiparous, in botany, is an epithet applied to the fruits which

produce leaves from their upper part.

Frons (Lat.), in zoology, the region of the cranium between the orbits and the vertex.

Frontal (Lat.), in anatomy, a term applied to parts connected with the anterior region or frontal part of the head; as, arteria frontalis (frontal artery), an artery which forms a branch of the ophthalmia; bosses frontales, two eminences, one situated on each side of the external surface of the frontal bone; cresta frontalis, a crest situated at the interior extremity of the frontal groove; musculus frontalis, muscle in the anterior hollow of the occipito-frontalis; os frontalis, the bone situated at the anterior part of the cranium; sutura frontalis, the suture which divides the os frontalis in the foetus.-Craig.

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Frost (Sax.), in physics, the temperature of air which occasions the congelation of water, when the thermometer sinks to or below 32° Fahrenheit. (See Freezing.)

Fructes'cence (Lat. fructus fruit), the precise time when the fruit of a plant arrives at maturity.-Fructification is the act of fructifying, which consists of the following parts, viz.: the calyx, corolla, stamen, pistil, pericarp, seed, and receptacle.

Fruit (Lat. fructus), in botany, a term properly applied to the ovarium of a fruit plant when it has attained maturity; generally speaking, fruit is whatever the earth produces for the nourishment of animals; the product of a tree or plant in which the seeds are contained, or which is taken for food.

Frustum (Lat.), in geometry, the part of a solid body next to the base, left by cutting off the top by a plane parallel to the base.-The frustum of a cone is the part cut off from a cone, which does not contain the vertex ;-Frustum of a pyramid, that part which remains after the top is cut off by a line parallel to the base; -Frustum of a globe or sphere is any part of it which is cut off by a plane.

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Fuca'cea (Lat. fucus paint), in botany, a nat. order of Alga (the Seawracks), of which Fucus is the genus. They are generally inhabitants of the ocean.-Fucea are a sub-order of the Fucaceæ, in which the frond polysiphonous, and often bladdery. -Fucoid, resembling sea-weed. Fuga'ta (Ital.), in music, compositions written in the style of fugues. Fugue (Ital. flying), in music, a com

position in which the different parts follow and repeat each other. Fulcrum (Lat. a prop), in botany, the support of a plant; a stipula.-In mechanics, the support or prop on which a lever rests.

Fulgora (Lat. fulgor brightness), in entomology, a genus of Moth Cicadas (the Lantern-fly), which emit light in the dark; fam. Flatidæ. Fulgurite (Lat. fulgor), in meteorology, a tube of vitrified sand, supposed to be formed by a stroke of lightning on a sandy plain, &c.; a term used to designate any mineral with marks of fusion, supposed to be from the action of lightning, as implied by the word.

Fuliguli'ne (Lat. fuligo blackness), in ornithology, a sub-family of the Anatidæ (the Sea-ducks), distinguished from the River-ducks by the broadness of the hinder toe.

Fuller's Earth, in mineralogy, a species of marl, having the property of absorbing grease.

Fulmin'ic Acid, in chemistry, an acid produced by the action of nitric acid on alcohol in the presence of a salt of silver or mercury, and forming a kind of very explosive salts. Fumar'amide, a snow-white powder formed by the action of aqua ammoniæ on fumarate of oxide of ethule.

Fumaria'ceae (Lat. fumus smoke), in botany, a nat. order of thalamifloral Exogens (the Fumeworts of Lindley), consisting of herbaceous plants, of which the Fumaria is the type and genus. Fu'marolles (Fr. from Lat. fumus smoke), in volcanic districts, those crevices in the earth from which steam and boiling fluids are emitted. Fungi (Lat. fungus a mushroom), in botany, an extensive nat. order of cellular and flowerless plants propagated in brown spores. That part in which the reproductive organs are placed is called the hymenium; the hollow base from which the stipe or stem arises is called the volva, or wrapper; the upper part is the cap, or pileus, the inferior radiating surface of which is called the gills, or lamina.

Fungic'ole (Lat. fungus, and colo to inhabit), in entomology, a family of coleopterous insects.

Fungus (Lat.), in surgical pathology, a spongy excrescence or soft cancer, being an unnatural and morbid growth. -Fungoid, like a fungus.-Fungous, consisting of or representing mush

rooms.

Fu'nicle (Lat. funiculus a little rope),

in botany, a stalk which attaches the seed to the placenta.

Funis (Lat. a rope), in anatomy, the umbilical cord, or navel string. Furfur (Lat. bran), in pathology, disease of the skin, in which the cuticle falls off in small scales like bran or meal.

Furibon'do (Ital.), in music, a word applied to movements intended to be performed with energy.

Furio'so (Ital.), in music, with great energy.

Furniture (Fr.), in typography, the materials for keeping the pages bound together, and regulating the proper margin. - In architecture, brass-work of locks, knobs of doors, window shutters, &c.

Furun'cle (Lat.), in pathology, an inflammatory tumour, commonly called a boil.

Fusarole' (Ital.), in architecture, a moulding placed under the echinus in the Doric, Ionic, and Composite capitals.

Fuse, in mining and blasting, a short metal tube charged with an explosive composition, and having a slow match attached, for firing a blastcharge or bomb-shell.-In military science, a tube fixed in the bore of a shell for exploding.

Fusees (Fr.), in horology, a cylinder, or part of a watch round which the

chain winds.-In gunnery, that part of a bomb or grenade which makes it take fire.

Fusel Oil (Germ. fusel), in chemistry, a deleterious component of alcohol, used in the manufacture of fruit essences. Fuselol is an oil of potato spirit, which is colourless, and possesses a strong and nauseous odour.

Fusi'ne (Lat. fusus a spindle), in malacology, a sub-family of Mollusca (the Spindle-shells), of which Fusus is the type and genus; fam. Turbinellida.

Fusing Point, in metallurgy, the degree of heat at which liquefaction takes place.

Fusion (Lat.), in metallurgy, the degree of heat at which a solid substance melts. Of the common metals the degrees of heat are-tin, 442°; bismuth, 497°; lead, 612°; zinc, 773; silver, 1173°; copper, 1996°; gold, 2016; cast-iron, 2786°.

Fustic, a wood of the tree Morus

tinctoria, used in dyeing yellow; chiefly brought from the West Indies. Futtocks, in navigation, the timbers of a ship between the floor timbers and the top ones. - Futtock shrouds, small shrouds.

Ga'bio, in mineralogy, the aggregate of saussurite and diallage.

Ga'bion (Fr.), in fortification, a large wicker basket filled with earth, to shelter the men from the enemy's fire.-Gabionnade is a bulwark of

gabions.

Ga'bionite, in mineralogy, a foliated scapolite, of a greyish-green colour, found in Norway, consisting of alumina, magnesia, potash and soda, protoxide of iron and manganese, and water: sp. gr. 30. Gad'ida (Lat. gadus), in ichthyology, a family of malacopterygious fishes (the Čod-fishes), of which the Gadus is the type and genus. Gadol'inite (from M. Gadolin, the discoverer), a rare hard mineral, of an iron-black colour, composed of yttria, glucina, protoxide of cerium, protoxide of iron, and silica; sp. gr. 4'2. Gahnite, in mineralogy, a greenish hard metal.

Gaiement (Fr. gaie lively), in music, a word denoting that the movement to which it is prefixed is to be performed in a lively, cheerful style. Galac'tia, or Galactirrhoe'a (Gr.galaktos, from gala milk, and rheo to flow), a morbid overflowing of milk. Galactic Circle, in astronomy, the circle at right angles to the diameter, forming the galactic pole.-The Galactic Poles are the opposite points of the celestial sphere, round which the stars are most scattered. Galac'tine (Gr. of milk), in chemistry, a milky and waxy substance. Galac'tite (Gr.), in mineralogy, a whitish fossil substance.

Galactoden'dron (Gr.), in botany, the Milk tree, or Cow tree. Galac'togogues (Gr.), medicines which promote the secretion and flow of

milk from the breast. Galactometer (Gr. gala milk, and metron

a measure), an instrument to ascertain the quality of milk; a lactometer. Galactopo'sia (Gr.), the method by which diseases are attempted to be cured by milk. From galaktos, of milk, we have Galactopyra, milk fever ;-Galactosis, secretion of milk;-Galacturia, discharge of a milk-like fluid by the urinary passages. Galaxy (Gr. galaxias), in astronomy, the milky way; a luminous tract or zone, seen in the evening encompassing the heavens.

Gale'na (Lat.), in mineralogy, a native sulphuret of lead.

Gall (Sax. gealla), in physiology and

animal economy, the bile, which is a bitter, yellowish-green fluid secreted in the liver.-Gall-stone is a calcareous concretion, or calculus, formed in the gall-bladder.-Gallbladder is a small membranous sac, which receives the bile from the liver. -Gall-ducts, in anatomy, the ducts or canals which convey the bile from the liver-Gall-nuts are powerfully astringent, and used in dyeing and ink-making.

Gallate (from gall), in chemistry, a neutral salt formed from the union of gallic acid with a base.

Gallery (Fr.), in fortification, a covered walk across a ditch in a besieged town, made of strong planks, and covered with earth.-In architecture, a long, narrow room, the width of which is at least three times less than its length, by which proportion it is distinguished from a saloon.-In mining, a narrow passage or branch of a mine carried on underground to a work designed to be blown

up.

Gallic (from gall), derived from galls, or oak-apples.-Gallic acid is an acid obtained in fine white needles from gall-nuts moistened, bruised, and exposed for four or five weeks to a temperature of about 80°. Gallic'ole (Lat. galla a gall-nut, and colo to inhabit), in entomology, a family of hymenopterous insects, whose larvæ inhabit gall-nuts.

Gallina'ceæ, or Galli'ne (Lat. gallus a

cock), in ornithology, an order of birds, of which the domestic Cock (Gallus) is the type, including Fowls, Pheasants, Grouse, &c.

Gallinsec'ta, a family of hemipterous insects-Gall-insects.

Gal'loper, in gunnery, a carriage that bears a gun of a pound-and-a-half ball.

Gallotan'nic Acid (Lat. galla gall, and tannin astringent), the pure tannin of nut-galls, employed for chemical