TRUSSING PIECES. Those timbers in a roof that are in a state of compression.
TRY. (Verb.) To plane a piece of stuff by the rule and square only.

TUBE (Lat.) A substance perforated longitudinally; generally quite through its length. TUCK POINTING. In old brickwork, after it has been well washed and the mortar raked out, the joints are filled with new mortar; the face of the work is then coloured yellow or red, as desired. Lines to mark the joints are made by putting on a ridge of lime putty with the point of the trowel over the new mortar, and cutting it straight and to the required width by means of a straight edge and knife. TUDOR STYLE. A name given to the late portion of the Perpendicular Gothic, from the line of sovereigns in England who reigned during its prevalence. The arch is of a four-pointed obtuse shape.

TUFA. A mass of volcanic earth, consolidated. Tufo is a mass of agglomerated sand without volcanic character. Tufaceous, mixed with tufo.

TUMBLED IN. The same as trimmed in. See TRIMMED.

TUMULUS. A barrow or artificial earth mound. Among the Celtic works the former was sepulchral, and the latter perhaps erected for beacons or for a memorial purpose. TUNNEL. (Fr.) A subterranean channel for carrying a stream of water under a road, hill, etc., or through which a road or railway is run.

TUN OF WATER. See WATER, Weight of.

TURNING PIECE. A board with a circular face for turning a thin brick arch upon. TURPENTINE. Turpentine is obtained by exudation and hardening of the juice flowing from incisions into pine trees. To obtain the oil of turpentine, the juice is distilled in an apparatus like the common still, and water is introduced with the turpentine. TURRET. (Lat. Turris.) A small tower often crowning the angle of a wall, etc. TUSCAN ORDER. The first of the five orders used in Roman and Italian architecture. See fig. 1454.

TUSK. A bevel shoulder made above a tenon, and let into a girder to give strength to the

tenon.

TYMPANUM. (Gr.) The naked face of a pediment (see PEDIMENT) included between the level and raking mouldings. See ETIAIOI and ETOMA. The word also signifies the die of a pedestal, and the panel of a door.

TYPE. (Gr. TUTOS.) A word expressing by general acceptation, and consequently applicable to, many of the varieties involved in the terms model, matrix, impression, &c. It is, in architecture, that primitive model, whatever it may have been. that has been the foundation of every style, and which has guided, or is supposed to have guided, the forms and details of each. What it was in each style is still only conjecture. TYPE. The canopy over a pulpit, also called a sound board.

U

UNDERCROFT. A vault under a church or chapel. See CRYPT, CROFT, and SHROWDS. UNDERPINNING. Bringing a wall up to the ground sill. The term is also used to denote the temporary support of a wall, whose lower part or foundations are defective, and the bringing up new solid work whereon it is in future to rest. See GOUFING. UNDERPITCH GROIN. See WELCH GROIN.

UNGULA. The portion of a cylinder or cone comprised by part of the curved surface, the segment of a circle, which is part of the base, and another plane.

UNIVERSITY. An assemblage of colleges under the supervision of a senate, etc.

UPHERS. Fir poles, from four to seven inches in diameter, and from twenty to forty feet in length. They are often hewn on the sides, but not entirely, to reduce them square. They are chiefly used for scaffolding and ladders, and are also employed in slight and common roofs, for which they are split.

UPRIGHT. The elevation of a building; a term rarely used.

URILLA. See HELIX.

URN. (Lat.) A vase of a circular form, destined among the ancients to receive and preserve the ashes of the dead. With the vase, it often forms a decoration to the pedestal of a balustrade on a terrace, top of a wall, etc.

V

VAGINA. (Lat.) The lower part of a terminal in which a statue is apparently inserted. VALLEY. (Lat.) The internal meeting of the two inclined sides of a roof. The rafter which supports the valley is called the valley rafter or valley piece, and the board fixed upon it for the leaden gutter to rest upon is called the valley board. The old writers called the valley rafters sleepers.

VALVE. (Lat.) Anything which opens on hinges or pivots as a door.

VANE. A plate of metal shaped like a banner fixed on the summit of a tower or steeple, to show the direction of the wind.

VANISHING LINE. In perspective, the intersection of the parallel of any original plane and the picture is called the vanishing line of such plane. The vanishing point is that to which all parallel lines in the same plane tend in the representation. VAPORARIUM. (Lat.) The same as CALDARIUM.

VARIATION OF CURVATURE. The change in a curve by which it becomes quicker or flatter in its different parts. Thus, the curvature of the quarter of an ellipsis terminated by the two axes is continually quicker from the extremity of the greater axis to that of the lesser. There is no variation of curvature in the circle.

VARNISH. A glossy coat on painting or the surface of any matter. It consists of different resins in a state of solution, whereof the most common are mastic, sandarac, lac, benzoin, copal, amber, and asphaltum. The menstrua are either expressed, or essential oils, or alcohol.

VASE. (Lat. Vas.) A term applied to a vessel of various forms, and chiefly used as an ornament. It is also used to denote the bell, or naked form, to which the foliage and volutes of the Corinthian and Composite capitals are applied. The vases of a theatre in ancient architecture were bell-shaped vessels placed under the seats to produce reverberation of the sound. See ECHEA.

VAULT. (It. Volto.) An arched roof over an apartment, concave towards the void, whose section may be that of any curve in the same direction. Thus a cylindric vault has its surface part of a cylinder. A full-centred vault is formed by a semi-cylinder. When a vault is greater in height than half its span, it is said to be surmounted; when less, surbased. A rampant vault springs from planes not parallel to the horizon. The double vault occurs in the case of one being above another. A conic vault is formed of part of the surface of a cone, as a spherical vault consists of part of the surface of a sphere. The plane of an annular vault is contained between two concentric circles. A vault is said to be simple when formed by the surface of some regular solid round one axis, and compound when formed of more than one surface of the same solid or of two different solids. A cylindro-cylindric vault is formed of the surfaces of two unequal cylinders; and a groined vault is a compound one rising to the same height in its surfaces as that of two equal cylinders, or a cylinder with a cylindroid. The reins of a vault are the sides or walls that sustain the arch. See FAN VAULTING.

The following table gives the clear breadths and heights in English feet, of the most remarkable vaulted avenues, as given by Mr. Garbett in his "Principles of Design in Architecture":

Thus St. Peter's has the same external height as Amiens but gives twice the breadth; yet both are considered well proportioned avenues in their respective styles. VAULTED CEILING. A ceiling built of stone, bricks, or blocks of wood, supporting itself on the principle of the arch.

VAULTING SHAFT. A pillar, sometimes rising from the floor, or only from the capital of a pier, or even only from a corbel, from the top of which spring the vaulting ribs of the groining.

VELARIUM. (Lat.) The great awning, which by means of tackle was hoisted over the Roman theatre and amphitheatre to protect the spectators from the rain or the sun's rays. VELLAR CUPola, A term used by Alberti to denote a dome or spherical surface terminated by four or more walls, frequently used over large staircases and salons, and other lofty apartments.

VENEER. A very thin leaf of wood of a superior quality, for covering furniture, etc., made of an inferior wood. Wafers of wood thirty-two inches wide were made about 1824. VENETIAN DOOR. A door having side lights on each side of its frame. VENETIAN STYLE. That style of modern Italian architecture formed by the architects of the Venetian states in the fifteenth to the early part of the seventeenth centuries. VENETIAN WINDOW. One formed with three apertures separated by slender piers from each other, whereof the centre one is much larger than those on the sides. VENT. The flue or funnel of a chimney; also any conduit for carrying off that which is offensive.

VENTIDUCT. A passage or pipe for the introduction of fresh air to an apartment. VENTILATION. The continual change of air to an apartment, or portion of an edifice, &c. The architect has to provide means for letting off or taking away the foul air, generally by apertures at the upper part of the room, etc., to which the hot air will ascend, as well as to provide for the admission of fresh air in sufficient quantities to take its place or to force it out without any appreciable current.

VERANDAH. An open gallery having a roof supported by light pillars, and placed over the windows of the principal rooms of a house to shelter them from the rays of the sun, and under which persons can promenade for fresh air. It is sometimes enclosed with glass screens to form a conservatory.

VERGE BOARDS. See BARGE BOARDS.

VERMICULATED WORK. (Lat.) A term applied to rustic-work which is so wrought as to have the appearance of having been eaten into by worms.

VERTEX. (Lat. the top.)

A term generally applied to the termination of anything finishing in a point, as the vertex of a cone, etc.

VERTICAL ANGLES. The opposite ones made by two straight lines cutting each other.
VERTICAL PLANE. One whose surface is perpendicular to the horizon.

VESICA PISCIS. (Lat. a fish's bladder.) A form which may be produced in the endeavour to gain two lines at right angles with each other. Arcs of circles inclosing two equilateral triangles drawn on the same base line will also produce it. It was a monogram, which has been supposed to be connected with the plan and form of churches erected during the medieval period. Many medieval seals of ecclesiastical and other communities were designed on the same form, and have been imitated of late for those of some archæological societies. See SYMBOLISM.

VESTIBULE. (Lat. Vestibulum.) An apartment which serves as the medium of communication to another room or series of rcoms. In the Roman houses it appears to have been the place before the entrance where the clients of the master of the house, or those wishing to pay their court to him, waited before introduction. It was not considered as forming a part of the house. The entrance from the vestibulum led immediately into the atrium, or into the cavædium.

VESTRY. (Lat. Vestiarium.) An apartment in, or attached to, a church for the preservation of the sacred vestments and utensils. A sacristy; see DIACONICUM. VIBRATION. A motion or combination of motions. The theory of the vibrations of the particles of an elastic fluid is the key to what is known of the phenomena of sound and light: and it is supposed that the causes of the sensible phenomena of heat, electricity, and magnetism will be found in the vibrations of matter of some kind. It is stated that iron kept constantly in a state of vibration oxidates less rapidly than that which is at rest, as exemplified in railway rails. It is recorded that the greatest vibration on the timber temporary bridge over the river Thames at Blackfriars was produced by empty four-wheel cabs. The vibration on the top platform, though it appeared considerable, was in fact only a quarter of an inch.

VICE or VIS. (Fr.) An old term applied to a spiral or winding staircase. In mechanics, a machine serving to hold fast anything worked upon, whether the purpose be filing, bending, riveting, etc.

VILLA. A country-house for the residence of an opulent person. Among the Romans there were three descriptions of villa, each having its particular destination, namely, the Villa urbana, which was the residence of the proprietor, and contained all the conveniences of a mansion in the city. The Villa rustica, which contained not only all that was essential to rural economy, such as barns, stables, etc., but comprised lodging apartments for all those who ministered in the operations of the farming establishment. The Villa fructuaria was appropriated to the preservation of the different productions of the estate, and contained the granaries, magazines for the oil, cellars for the wine, etc.

VILLAGE HOSPITAL. A class of building lately recommended to be formed in small localities for the purpose of preventing the spread of fevers, &c., by at once placing the sick under proper treatment.

VIMANA. The name for the temple of the Hindoos, in front of which is the mantapa or porch, and again the gopura or pyramidal entrance gateway.

VINERY. A house for the cultivation of vines. See CONSERVATORY.

VISORIUM. (Lat.) See AMPHITHEATRE.

VISUAL POINT. In perspective a point in the horizontal line in which the visual rays unite. VISUAL RAY. A line of light supposed to come from a point of the object to the eye. VITRUVIAN SCROLL. See SCROLL.

VITRIFICATION. The hardening of argillaceous stones by heat. See BRICK; TERRA COTTA. Vivo. (Ital.) The shaft of a column.

VOLUTE. A spiral scroll which forms the principal feature of the capital of the Ionic order in Greek and Roman architecture. The capital of the Corinthian order has one smaller in size (HELIX), which is enlarged in that of the Composite order. Several methods have been put forward of describing the spiral lines of the Ionic volute. The returns or sides are called pulvinata or pillows. Balteus is the outer fillet on the side of the volute. VOMITORIUM. (Lat.) See AMPHITHEATRE.

VOUSSOIR. (Fr.) Á wedge-like stone or other matter forming one of the pieces of an arch. See ARCH. The centre voussoir is called a keystone.

VULCANISED INDIA RUBBER. A material perhaps only brought into requisition by the architect for the purpose of excluding draughts from doors and the entry of dust into closets or cases. As a tube, with or without a spiral wire in it, it is greatly used for movable gas-lights.

W

WAGGON-HEADED CEILING. The same as cylindrical ceiling. See VAULT.

WAINSCOT. (Dutch, Wayschot.) A term usually applied to the oak or deal lining of walls in panels. The wood originally used for this purpose was a foreign oak, and called wainscot, hence the name of the material became attached to the work itself.

WALL. A body of material for the enclosure of a building and the support of its various parts. External wall" shall apply to every outer wall or vertical enclosure of any building, not being a party wall (Metropolitan Building Act, 1855.) "Cross wall" shall apply to every wall used or built in order to be used as a separation of one part of any building from another part of the same building, such building being wholly in one occupation. (Idem.) See Party wall.

WALINGS. See SHORING.

WALLS OF THE ANCIENTS. See MASONRY.

WALLS, CASED. Those faced up anew round a building, in order to cover an inferior material, or old work gone to decay.

WALNUT. A forest tree used in cabinet work.

WASHER. A flat piece of iron, or other metal, pierced with a hole for the passage of a screw, between whose nut and the timber it is placed, to prevent compression on a small surface of the timber. Also the perforated metal plate of a sink or drain, which can be removed for letting off the waste water, and thus more easily cleansing it.

WASTING. Splitting off the surplus stone from a block, with a point or a pick, reducing it to nearly a plane surface. In Scotland it is called clouring.

WATER. See WEIGHT.

WATER JOINT. A joint between two stones in the paving of a terrace, where each side of the joint for about an inch is made level and then rounded off into a sinking of the stones, to prevent water lodging in the joint, especially if occasionally covered with it, as a river landing-place.

WATER JOINT HINGE. A hinge made into a sort of loop at the turning part, whereby it is less likely to stiffen by rusting, as it is generally used in out-door work. WATER SHOOT. See SQUARE SHOOT.

WATER SUPPLY. See PLUMBERY. See AQUEDUCT.

WATER TABLE. An inclined plane where a wall sets off to a larger projection, for the purpose of throwing off any water that may fall upon that plane, and is principally used to buttresses and other similar parts of medieval buildings: but in all styles it is an efficient way of attaining the above desirable object. Where a stone entablature occurs, the top is often covered with lead to prevent water soaking through. WAVES. In many engineering works, the weight of the stone to be employed is of the utmost importance, especially for low buildings occasionally under water, where there is a rapid current, or where they are subject to the influence of powerful waves. Such circumstances will require a heavier stone to be used than may at first have been considered necessary, because all bodies immersed are reduced in weight by so much as is equal to that of the bulk of water which they displace. The force of the waves at Skerryvore lighthouse was found to be 4,335 lbs. per square foot; that at Bell Rock

lighthouse was 3,013 lbs. The highest force observed was 6,000 lbs. For weight of water, see Weight.

WEATHER BOARDING. Boards nailed with a lap on each other, to prevent the penetration of the rain and snow. The boards for this purpose are generally made thinner on one edge than on the other, especially in good permanent work. The feather-edged board is, therefore, used in such cases, the thick edge of the upper board being laid on the thin edge of that below, lapping about an inch or an inch and a half, and the nails being driven through the lap.

WEATHER MOULDING. A moulded string course.

The projecting moulding of an arch, having a weathered or sloped surface at top, serving to throw off the rain, and to protect the other mouldings. See HOOD MOULD.

WEATHER TILING and SLATING. The covering an upright wall with tiles, or with slates. WEDGE. (Dan. Wegge.) An instrument used for splitting wood or other substances; it is usually classed among the mechanical powers.

WEIGHT. (SAX. Wiht.) In mechanics, a quantity determined by the balance; a mass by which other bodies are examined. It denotes anything to be raised, sustained, or moved by a machine as distinguished from the power, or that by which the machine is put in motion.

WEIGHT, in commerce. A body of given dimensions, used as a standard of comparison for all others. By an act of parliament passed in June, 1824, all weights were to remain as they then were, that act only declaring that the imperial standard pound troy shall be the unit or only standard measure of weight from which all other weights shall be derived and computed; that this troy pound is equal to the weight of 22.815 cubic inches of distilled water weighed in air at the temperature of 62° of Fahrenheit's thermometer, the barometer being at 30 inches, and that there being 5760 such grains in a troy pound, there will be 7,000 grains in a pound avoirdupois. TROY WEIGHT.

The avoirdupois pound: pound troy:: 175: 144, or::11 : 9 nearly; and an avoirdu. pois pound is equal to 1 lb. 2 oz. 11 dwts. 16 grains troy. A troy ounce = 1 oz. 1.55 dr. avoirdupois.

The following is a table of weights according to the French system.

The following table exhibits the proportion of weights in the principal places of Europe to 100 lbs. English avoirdupois.