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from which he calculated the height of the modulus of elasticity of brass plate to be 4,940,000 feet, or 18,000,000 lbs. for its weight to a base of 1 square inch. For wire of inferior brass he found the height to be 4,700,000 feet.

As cast brass had not been submitted to experiment, a cast bar of good brass was procured, with which the following experiment was made:

The bar was filed true and regular: its depth was 0-45 inch, and breadth 0.7 inch; the distance between the supports was 12 inches, and the scale suspended from the middle.

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it took no perceptible set.

relieved, the set was 01.

0.18 slipped between the supports, bent more than 2 inches, but did not break.

Hence 52tbs. seems to be about the limit which could not be much exceeded without permanent change of structure. It is equivalent to a strain of 6700 tbs. upon a square inch, and the corresponding extension is of its length. Absolute cohesion above 21,000 lbs. per square inch. The modulus of elasticity according to this experiment is 8,930,000 tbs. for a base of an inch square. The specific gravity of the brass is 8.37, whence we have 2,460,000 feet for the height of the modulus. Expression principally consists in representing the human body and all its parts in the action suitable to it; in exhibiting in the face the several passions proper to the figures, and marking the motions

they impress on the other external parts Expression, in painting, consists in the representation of those attitudes of the body, and variations of the countenance, which always accompany and indicate the immediate influence of the passions on the mind

Expression of colour. Every pas

sion and affection of the mind has its appropriate tint; and colouring, if properly adapted, lends its aid, with powerful effect, in the just discrimination and forcible expression of them: it heightens joy, warms love, inflames anger, deepens sadness, and adds coldness to the cheek of death itself. External thermometer (the) should be a mercurial one, well exhausted of air, and the graduated scale divided to tenths of a degree, or into quarters of a degree, or with whole divisions large enough to be divided into as many parts by the eye. Choose a locality for the instrument, where it will be well exposed to the ambient air,-apart from the reflection of sunbeams, &c., and where it may be distinctly read off without inconvenience. It should be read off as quickly as possible. For uniformity of system, it should be read off at stated periods, the same time at which the barometer, &c., are noted, and carefully watched in the interim, to see whenever any remarkable change occurs; before and after storms, during eclipses of the sun and moon, or the passage of dense clouds of vapour, &c. Extract of gamboge is the colouring matter of gamboge separated from its greenish gum and impurities by solution in alcohol and precipitation, by which means it acquires a powdery texture, rendering it miscible in oil, &c., and capable of use in glazing. It is at the same time improved in colour, and retains its original property of working well in water and gum.

Extrados, the exterior curve of an arch, measured on the top of the voussoirs, as opposed to the soffit or intrados

Eye, a name given to certain circular parts and apertures in architecture,

FAB

FABER, a name given by the Romans to any artisan or mechanic who worked in hard materials Fabrica, according to the Romans, the workshop of any mechanic Fabrilia, according to Horace, mechanics' tools

Façade, the face or front of any considerable building to a street, court, garden, or other place Face-piece, in ship-building, a piece wrought on the fore-part of the knee of the head, to assist the conversion of the main-piece, and to shorten the upper bolts of the knee of the head

Fahrenheit, a native of Dantzic, was

born in 1686: he invented the scale so called after his name: he also improved the thermometer by substituting mercury instead of spirits of wine, and formed a new scale for the instrument, founded on accurate experiments, fixing the freezing point of water at 32°, and that of boiling at 212°

Faldstool, or folding stool, a portable

seat made to fold up in the manner of a camp stool: it was made either of metal or wood, and sometimes covered with rich silk False roof, the space between the ceiling and the roof above it, whether the ceiling is of plaster or a stone vault, as at King's College chapel, Cambridge, and St. Jaques' church, Liége Fan-tracery vaulting: this was used in late Perpendicular work, in which all the ribs that rise from the springing of the vault have the same curve, and diverge equally in every direction, producing an effect like the bones of a fan: very fine examples of it exist in Henry the

but more especially to the central circle of the Ionic volute; to the circular or oval window in a pediment; to a small skylight in a roof, or the aperture at the summit of a cupola

FAR

VIIth's chapel, Westminster, St. George's chapel, Windsor, and King's College chapel, Cambridge Fanal, a pharos or lighthouse, or the lantern placed in it

Fanum, a Roman temple or fane, usu

ally consecrated to some deity Fang, in mining, a niche cut in the side of an adit, or shaft, to serve as an air course: sometimes a main of wood pipes is called a fanging Fanners, vanes or flat discs revolving round a centre, so as to produce a current of air; generally used instead of bellows for forges Farm. Vitruvius says-"The mag

nitude of the buildings must depend wholly upon the quantity of land attached to them, and upon its produce. The number of courts and their dimensions must be proportioned to the herds of cattle and the quantity of oxen employed. The kitchen should be situated in the warmest part of the court, and the stable for the oxen contiguous to it: the stalls should be made to face the hearth and the east; because when oxen are constantly exposed to light and heat, they become smooth-coated. No husbandman, however ignorant, will suffer cattle to face any other quarter of the heavens than the east. The width of the stables ought not to be less than ten nor more than fifteen feet, their length proportioned to the number of yokes, each of which should occupy an extent of seventeen feet. The scalding-rooms should adjoin the kitchen, in order that the operation of cleaning the utensils may be performed upon the spot. The courts for sheep, &c., should be

so spacious as to allow not less than four and a half nor more than six feet to each animal.

"The granaries should be above ground, and made to front either the north or the north-east, in order that the grain may not be liable to ferment; but, on the contrary, by exposure to a cold atmosphere, may be preserved a long time: all other aspects encourage the propagation of worms and insects destructive to grain. The stables should be built in the warmest part of the villa, most distant from the hearth; because when horses are stalled near fire they become rough-coated. It is likewise expedient to have stalls for oxen at a distance from the kitchen, in the open air these should be placed so as to front the east, because if they are led there to be fed in winter, when the sky is unclouded they will improve in appearance. The barns, the hay-yards, the cornchambers, and the mills, ought to be without the walls; so that the farm may be less liable to accidents from fire."

Farm, in Cornish mining, that part

of the lord's fee which is taken for liberty to work in tin mines only that are bounded, which is generally one-fifteenth of the whole Fascia, a flat architectural member in an entablature or elsewhere; a band or broad fillet. The architrave in the more elegant orders of architecture is divided into three bands, which are called fasciæ: the lower is called the first fascia, the middle one the second, and the upper one the third fascia.

Fascia, the bands of which the epistylium of the Ionic and Corinthian orders are composed. The antepagments of Ionic doorways were generally divided into three fasciæ or corsæ. Fascia were bands which the Romans were accustomed to bind round the legs. Fast and loose pulleys, two pulleys placed side by side on a shaft

which is driven from another shaft by a band: when it is required to stop the shaft, the band is transferred to the loose pulley Fastigium, the pediment of a portico; so called because it followed the form of the roof, which was made like a triangle, the sides being equally inclined to carry off the water

Fastigium, in architecture, the summit, apex, or ridge of a house or pediment

Faux, according to Vitruvius, a narrow passage which formed a communication between the two principal divisions of a Roman house, -the atrium and peristylium Fay, in ship-building, to join two pieces of timber close together Feathering, or foliation, an arrangement of small arcs or foils separated by projecting points or cusps, used as ornaments in the mouldings of arches, &c. in Gothic architecture

Feed-head, a cistern containing water

and communicating with the boiler of a steam engine by a pipe, to supply the boiler by the gravity of the water, the height being made sufficient to overcome the pressure within the boiler Feed-pipe, the pipe leading from the feed-pump, or from an elevated cistern, to the bottom of the boiler of a locomotive engine Feed-pipe cocks, those used to regulate the supply of water to the boiler of a locomotive engine, and the handle of which is placed conveniently to open and shut at pleasure Feed-pipe strainer, or strum, a perfo

rated half-spherical piece of sheet iron, after the manner of the rose end of a watering pot: it is placed over the open end of the feed-pipe in the locomotive tender tank, to protect it

Feed-pipes, the copper pipes reaching from the clack-box to the pump and from the pump to the tender, to convey water to the boiler of a locomotive engine

Feed-pump, a forcing-pump, worked by the steam engine, for supplying the boiler with water Feed-pump plunger, the solid piston, or enlarged end of the pump-rod, fitting the stuffing-box of the pump of a steam engine Felling timber, the act of cutting down a full-grown tree, which doubtlessly should be done late in the autumn, when less moisture exists in all trees, and which renders the timber less liable to dryrot

Felspar, a mineral of foliated structure

Felucca, in navigation, a little vessel used in the Mediterranean, capable of going either stem or stern foremost; also a small open boat, rowed with six oars

Femerell, a lantern, louvre, or covering placed on the roof of a kitchen, hall, &c. for the purpose of ventilation or the escape of smoke Femur, in architecture, the long flat projecting face between each channel of a triglyph; the thigh, or a covering for the thigh Fender-piles, those driven to protect

work either on land or in water Fenestella, the niche at the side of an altar containing the piscina; a vessel for holding water to wash the hands of the officiating priest; also a little window

Fenestra, a window, an entrance Fenestral: window-blinds or case

ments closed with paper or cloth, instead of glass, are so termed Fenestration, termed by the Germans Fenster-architektur, is, in contradistinction to columniation, the system of construction and mode of design marked by windows. Fenestration and columniation are so far antagonistic and irreconcileable, that fenestration either interferes with the effect aimed at by columniation with insulated columns, as in a portico or colonnade, or reduces it, as is the case with an engaged order, to something quite secondary and merely decorative.

Astylar and fenestrated ought, therefore, to be merely convertible terms; but as they are not, that of columnar-fenestrated has been invented, to denote that mode of composition which unites fenestration with the semblance, at least, of the other. Employed as a collective term, fenestration serves to express the character of a building or design with regard to the windows generally: thus it is said, the fenestration is excellent, or the contrary, ornate or meagre,-well arranged or too crowded,-which last circumstance is a very common fault, and is destructive both of grandeur and of repose.

Feretory, a bier, or coffin; a tomb or

shrine

Ferrule, a metal ring fixed on the

handle of a tool to prevent the wood from splitting

Fesse, in heraldry, a band or girdle possessing the third part of the escutcheon over the middle Festoon, an ornament of carved work,

representing a wreath or garland of flowers or leaves, or both interwoven with each other: it is thickest in the middle, and small at each extremity, a part often hanging down below the knot

Festoon, in architecture, an ornament of carved work, in the form of a wreath or garland of flowers, or leaves twisted together

Fictile, an earthen vessel or other article, moulded and baked Fictor, among the Romana, an artist, a deviser, or potter

Field, in heraldry, the whole surface of the shield

Figulus, an artist who makes figures and ornaments

Filagree, in the arts, a kind of en

richment in gold and silver File, a well-known instrument having teeth on the surface for cutting metal, ivory, wood, &c.

File, a strip or bar of steel, the sur

face of which is cut into fine points or teeth, which act by a species of cutting closely allied to abrasion.

When the file is rubbed over the material to be operated upon, it cuts or abrades little shavings or shreds, which, from their minuteness, are called file-dust, and, in so doing, the file produces minute and irregular furrows of nearly equal depth, leaving the surface that has been filed more or less smooth, according to the size of the teeth of the file, and more or less accurately shaped, according to the degree of skill used in the manipulation of the instrument. The files employed in the mechanical arts are almost endless in variety. Finial, sometimes called a pinnacle, but more truly confined to the bunch of foliage which terminates pinnacles, canopies, pediments, &c. in Gothic architecture

Finite force, a force that acts for a finite time, such as the force of gravity

Fillet, a small flat face or band, used principally between mouldings to separate them from each other in classical architecture: in the Gothic, Early English, or Decorated styles of architecture, it is also used upon larger mouldings and shafts Finlayson's Tables of the value of life assurance and annuities differ in several respects widely from either the Northampton or the Carlisle calculated Tables. In framing them for Government annuities from observations made on the mortality in tontines and amongst the holders of Government annuities, Mr. Finlayson, in his calculations, is inclined to take a favourable view of the duration of human life, and his Tables coincide very nearly with the Carlisle, except that he makes a distinction between males and females, the latter being considered rather longer lived than the former. As regards annuities, these observations may be thus illustrated: the present value of an annuity of £1 for the life of a person aged twenty-five, calculated at 4 I per cent. interest, would be, according to the

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Northampton Tables, 15 4 Carlisle do. Government, Male 16 9 Do.. . Female. 18 1 Fire-bar frame, in alocomotive engine, a frame made to fit the fire-box on which the fire-bars rest: a plan of dropping all the bars at once by a moveable frame, acted on by a lever and handle outside the fire-box, has been frequently tried, but the action of the intense heat soon puts it out of working order Fire-bars, in a locomotive engine, wedge-shaped iron bars fitted to the fire-box with the thick side uppermost, to support the fire: the ends rest on a frame: they are inclined inwards, with an air space between each, to promote combustion, and are jointed at one end, and supported by a rod at the other, so that the rod being withdrawn, the bars fall, and the fire-box is emptied

Fire-box, in a locomotive engine, the box (usually made of copper) in which the fire is placed. The outside is of iron, separated from the copper fire-box by a space of about 3 inches all round for water Fire-box door, the door opening into the fire-box, facing the locomotive tender, by which coke is supplied to the fire Fire-box partition: in large fire-boxes a division is made in the box, into which water is admitted: this division is about the height of the fire-box door, and divides the fire into two parts in a locomotive engine, thereby increasing the heating surface of the fire-box

Fire-box stays, in a locomotive engine, deep strong iron stays bolted to the top of the copper fire-box, to enable it to resist the pressure of the steam round copper or iron stays are also used to connect the outside shell to the inside box, in the proportion of about one stay to every 4 square inches of flat surface Fire-brick or Fire-bricks are used for

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