room itself. Skirting is either scribed close to the floor or let into it by a groove; in the former case a fillet is put at the back of the skirting to keep it firm.

SKIRTS. Several superficies in a plane, which would cover a body when turned up or down without overlapping.

SKREEN. See SCREEN.

SKYLIGHT. A frame consisting of one or more inclined planes of glass, placed in a roof to light passages or rooms below.

SLAB. An outside plank or board sawed from the sides of a timber tree, and frequently of very unequal thickness. The word is also used to express a thin piece of marble, consisting of right angles and plane surfaces. See CHIMNEY.

SLATE. See Book II. Chap. II. Sect. 8.

SLATERS' WORK. See Book III. Chap. II. Sect. 6.

SLEEPERS. Horizontal timbers disposed in a building next to the ground transversely under walls, ground joists, or the boarding of a floor. When used on piles they are laid upon them, and planked over to support the superincumbent walls. Underground joists either lie upon the solid earth, or are supported at various parts by prop stones. When in the former position, having no rows of timber below, these ground joists are themselves called sleepers. Old writers on practical architecture call those rafters lying in the valley of a roof, sleepers; but in this sense the word is now obsolete. SLIDING RULE. One constructed with logarithmic lines, so that by means of another scale sliding on it, various arithmetical operations are performed merely by inspection. SLIT DEAL. See BOARD.

SLUICE. A stop against water for the drainage or supply with water of a place. It is hung with hinges from the top edge when used merely as a stop against the water of a river; but when made for supply as well, it moves vertically in the groove of its frame by means of a winch, and is then called a penstock.

SMITHERY and IRONMONGERY. See Book II. Chap. III. Sect. 10.

SMOOTHING PLANE. See p. 364.

SNACKET. A provincial term for the hasp of a casement.

SNIPE'S BILL PLANE. One with a sharp arris for getting out the quirks of mouldings. SOANE. See ARCHITECTS, list of, 316.

SOCKET CHISEL. A strong tool used by carpenters for mortising, and worked with a mallet. SOCLE OF ZOCLE. A square member of less height than its horizontal dimension, serving to raise pedestals or to support vases or other ornaments. The socle is sometimes continued round a building, and is then called a continued socle. It has neither base nor

cornice.

A

SOFFITA, SOFFIT, or SOFITE. (Ital.) A ceiling; the lower surface of a vault or arch. term denoting the under horizontal face of the architrave between columns; the under surface of the corona of a cornice.

SOILS. A provincial term, chiefly, however, used in the north, signifying the principal rafters of a roof.

SOLDER. A metallic composition used in joining together or soldering metals. SOLID. (Lat.) In geometry, a body which has length, breadth, and thickness; that is, it is terminated or contained under one or more plane surfaces, as a surface is under one or more lines. Regular solids are such as are terminated by equal and similar planes, so that the apex of their solid angles may be inscribed in a sphere.

SOLID ANGLES. An angle formed by three or more angles in a point, and whereof the sum of all the plane angles is less than three hundred and sixty degrees, otherwise they would constitute the plane of a circle and not of a solid.

SOLID SHOOT. See WATER SHOOT.

SOLIVE. The French term for a joist, rafter, or piece of wood, either slit or sawed, with which builders lay their ceilings. The term is rarely used in the English language. SOMMERING. See SUMMERING.

SORTANT ANGLE. The same as SALIENT ANGLE, which see.

SOSTRATUS. See ARCHITECTS, list of, 25.

SOUFFLOT. See ARCHITECTS, list of, 299.

SOUND-BOARD. The same as a canopy or type over a pulpit, to reverberate the voice of the speaker.

SOUND-BOARDING. In floors, consists of short boards placed transversely between the joists, and supported by fillets fixed to the sides of the latter for holding pugging, which is any substance that will prevent the transmission of sound from one story to another. The narrower the sound-boards the better. The fillets on which they rest may be about three-quarters of an inch thick and about an inch wide, nailed to the joists at intervals of a foot. See BOARDING FOR PUGGING.

SOUSE (Fr.) or SOURCE. A support or under-prop.

SPAN. An imaginary line across the opening of an arch or roof, by which its extent is

SPAN ROOF. One consisting of two inclined sides, in contradistinction to shed or leanto roofing. It may be with simple rafters, with or without a collar beam, or when of increased span it may be trussed, the term only applying to the external part. SPANDREL. The irregular triangular space between the outer curve or extrados of an arch, a horizontal line from its apex, and a perpendicular line from its springing. SPANDREL BRACKETING. A cradling of brackets fixed between one or more curves, each in a vertical plane, and in the circumference of a circle whose plane is horizontal. SPANISH ARCHITECTURE. See Book I. Chap. II. Sect. 19.

SPAR-PIECE. A name given in some places to the collar beam of a roof. SPARS. The common rafters of a roof for the support of the tiling or slating. SPECIFICATION. A description at length of the materials and workmanship to be used and employed in the erection of any building. See Book II. Chap. III. Sect. 13. SPECIFIC GRAVITY. A gravity or weight of every solid or fluid compared with the weight of the same magnitude of rain water, which is chosen as the standard of comparison, on account of its being subject to less variation in different circumstances of time, place, &c., than any other solid or fluid. By a fortunate coincidence, at least to the English philosopher, it happens that a cubic foot of rain water weighs 1000 ounces avoirdupois; consequently, assuming this as the specific gravity of rain water, and comparing all other bodies with this, the same numbers that express the specific gravity of bodies will at the same time express the weight of a cubic foot of each in avoirdupois ounces, which affords great facility to numerical computations. Hence are readily deduced the following laws

of the specific gravity of bodies:

1. In bodies of equal magnitudes the specific gravities are directly as the weights or as their densities. 2. In bodies of the same specific gravities the weights will be as the magnitudes. 3. In bodies of equal weights the specific gravities are inversely as the magnitudes. 4. The weights of different bodies are to each other in the compound ratio of their magnitudes and specific gravities.

Thus it is obvious, that if of the magnitude, weight, and specific gravity of a body any two be given, the third may be found; and we may thus arrive at the magnitude of bodies which are too irregular to admit of the common rules of mensuration; or, by knowing the specific gravity and magnitude, we may find the weight of bodies which are too ponderous to be submitted to the action of the balance or steel yard; or, lastly, the magnitude and weight being given, we may ascertain their specific gravities.

TABLE OF SPECIFIC GRAVITIES

(Extracted from Davies, Lavoisier, Young, and other authentic sources).

Water at 60° is assumed 1000 specific gravity.

Mineral Productions.

Note.

556

529

SPECUS. (Lat.) In ancient architecture, the canal into which the water flowed in aqueducts raised above the surface of the ground, and constructed of hewn stones or bricks. It was covered with a vault to preserve the water from the sun, and from being mixed with rain water. The specus was sometimes covered with flat stones, laid horizontally, as in the Aqua Martia, part of the Aqua Claudia, and the aqueduct of Segovia. Sometimes the same arcade carried several of these canals one above the other.

SPHÆRISTERIUM. A building for the exercise of the ball; a tennis court. The ancients generally placed sphæristeria among the apartments of their baths and gymnasia. They were also placed in large villas, as in those of Pliny the younger. SPHERE. (Gr. Σpaipa.) A solid, whose surface is at every point equally distant from a certain point within the solid, which point is called the centre of the sphere. Every sphere is equal to two-thirds of its circumscribing cylinder, that is, it is equal to a cylinder whose ends are circles, equal to a great circle of the sphere, and whose height is equal to the diameter of the same.

SPHERICAL BRACKETING. That so formed that the surface of the plastering which it is to receive forms a spherical surface.

SPHEROID. See CONOID.
SPHEROIDAL BRACKETING.

SPINA. See CIRCUS.

That formed to receive the plastering of a spheroid.

SPINTHARUS. See ARCHITECTS, list of, 9.

SPIRAL. A curve which makes one or more revolutions round a fixed point, and does not return to itself.

SPIRE. (Gr. Zaupa, a twisting.) In ancient architecture, the base of a column, and sometimes the astragal or torus; but among the moderns it designates a steeple diminishing as it ascends, either pyramidally or conically.

SPLAYED. A term applied to whatever has one side making an oblique angle with the other thus, the heading joists of a boarded floor are frequently splayed in their thickness; as are also the jambs or sides of a window. In the latter case, the practice is for the better lighting of a room. The word fluing is sometimes applied to an aperture, in the same sense as splayed. SPRING BEVEL OF A RAIL.

The angle made by the top of the plank, with a vertical plane touching the ends of the railpiece, which terminates the concave side. SPRINGED. In boarding a roof, the setting the boards together with bevel joints, for the purpose of keeping out the rain.

SPRINGER. The impost or place where the vertical support to an arch terminates, and the curve of the arch begins; the term is sometimes used for the rib of a groined roof. Springing CoursSE. The horizontal course of stones, from which an arch springs or rises; or that row of stones upon which the first arch stones are laid. SQUARE. (Lat. Quadra.) A figure of four equal sides, and as many equal angles; also, an area of such form surrounded by houses, and ornamented in the centre with a lawn, shrubs, trees, &c. In joinery, a work is said to be square framed, or framed square, when the framing has all the angles of its styles, rails, and mountings square without being moulded. The word is also applied to an instrument for setting out angles square. See CARPENTER'S SQUARE.

SQUARE SHOOT. A wooden trough for discharging water from a building.

SQUARE STAFF. A piece of wood placed at the external angle of a projection in a room to secure the angle, which if of plaster would be liable to be broken, and at the same time to allow a good finish for the papering.

SQUARING A HANDRAIL. The method of cutting a plank to the form of a rail for a staircase, so that all the vertical sections may be right angles.

SQUARING A PIECE OF STUFF. The act of trying it by the square, to make the angles right angles.
STABLE. (Lat.) A building for the accommodation of horses.
STACK OF CHIMNEYS. See CHIMNEY.

STADIUM. (Gr.) In ancient architecture, an open space wherein the athleti or wrestlers
exercised running, and in which they contested the prizes. It signifies also the place
itself where the public games were celebrated, often formed a part of the gymnasia. The
word also denotes a measure of length among the Grecians, of 125 paces.
STAFF-BEAD. See ANGLE-BEAD.

STAGE. A floor or story. In a theatre, the floor on which the performers act. The stage of a buttress is, in ecclesiastical architecture, the part between one splayed projection and

the next.

STAIR. (Sax, Stægen, to step.) A stone, or piece of other material, by which a person raises himself one step. A series of steps or stairs for ascending from the lower to the upper part of a building, when enclosed by a wall, is called a staircase. STAIRCASE. That part or subdivision in a building containing the stairs, which enable persons to ascend or descend from one floor to another. See Book III. Chap. I. Sect. 23, for its construction.

SPALK. (Sax.) An ornament in the Corinthian capital, which is sometimes fluted, and resembles the stalk of a plant; from it spring the volutes and helices.

STALL. (Sax.) A place or division in a stable wherein one horse is placed for feeding and sleeping. According to their number in a stable it is called a one-stall, two-stall, &c. stable. This word is also used to denote an elevated seat in the choir or chancel of a church appropriated to an ecclesiastic, such as the prebendal stall of a cathedral.

STANCHION. (Fr. Estançon.) A prop or support. The upright mullions or bars of a window or open screen. Also a PUNCHION, which see.

STANDARDS. The upright pieces in a plate rack, or above a dresser, to support the shelves thereover.

When the edges of standards are cut into mouldings across the fibres of the wood they are called cut standards.

STAPLE. A small piece of iron pointed at each end, and bent round, so that the two ends may be parallel to each other, and of equal lengths, to be driven into wood or into a wall, thus forming a loop for fastening a hasp or bolt.

STARLINGS OF STERLINGS, Sometimes called STILTS. An assemblage of piles driven round the piers of a bridge to give it support.

STATICS. See MECHANICS.

STATUARY MARBLE. See Book II. Chap. II. Sect. 3.

STAVES. Small upright cylinders, sometimes called rounds, for forming a rack to contain the hay in stables for the supply of it to the horses.

STAY. A piece performing the office of a brace, to prevent the swerving of the piece to which it is applied. The term is general, and applies to all materials.

STEEL. (Sax. Stal.) Iron united with carbon, which is accomplished in two ways, by fu. sion and by cementation; the former is used to convert iron into steel immediately from the ore, or from crude or cast-iron; the last-named process is effected by exposing iron, covered with charcoal, to a strong continued heat. The process for converting iron into steel was known to the ancients.

STEENING. The brickwork laid dry used for forming the cylindrical shaft of a well or cesspool, whose office is to prevent the irruption of the surrounding soil.

STEEPLE. (Sax. Stepel.) A lofty erection attached to a church, chiefly intended to contain its bells. The word is a general term, and applies to every appendage of this nature, whether tower or spire, or a combination of the two.

STEPS. The same as STAIR, which see.

STEREOBATA. See PEDESTAL.
STEREOGRAPHIC PROJECTION.

That projection of the sphere wherein the eye is supposed

to be placed on the surface. STEREOGRAPHY. (Gr. Erepeos, solid, and rpapw, I describe.) That branch of solid geometry which demonstrates the properties and shows the construction of all regularly defined solids; it explains the methods for constructing the surfaces on planes, so as to form the entire body itself, or to cover its surface; or, when the solid is bounded by plane surfaces, the inclination of the planes. STEREOTOMY.

forms.

The science of cutting solids to suit certain conditions required for their

STILE. (Sax.) The vertical part of a piece of framing into which, in joinery, the ends of the rails are fixed by mortises and tenons; the tenon has the name, where, in other material than wood, any imitation of framing appears.

STILTS. See STARLINGS.

STOA. (Gr.) In Grecian architecture, a term corresponding with the Latin porticus, and the Italian portico.

STOCK. The part of a tool for boring wood with a crank whose end rests against the breast of the workman, while with one hand he holds the boring end steady, and with the other turns the crank; the steel borers are called bits, and the whole instrument is called a stock and bit.

STONE. (Sax.) A natural indurated substance found beneath and on the surface of the earth in almost every part of the world, and which for its strength and durability has been universally employed for building purposes. See Book II. Chap. II. Sect. 1. STOOTHINGS. A provincial term which signifies the battening of walls.

STOP-COCK.
A cock used in plumbery to turn off the supply to a reservoir,
STORY. (Lat. or Sax. Stop.) One of the vertical divisions of a building; a series of apart-

ments on the same level.

STORY POSTS. Upright timbers disposed in the story of a building for supporting the superincumbent part of the exterior wall through the medium of a beam over them; they are chiefly used in sheds and workshops, and should have either a solid wall below or stand upon a strong wooden sill upon inverted arches, or upon large stones, with their ends let into sockets.

STORY ROD.

One used in setting up a staircase, equal in length to the height of the story,