CLAY.

In ordinary language, any earth which possesses sufficient ductility to admit of being kneaded with water. Common clays may be divided into three classes, viz. unctuous, meagre, and calcareous. Of these the first is chiefly used in pottery, and the second and third are employed in the manufacture of bricks and tiles.

CLAYING. The operation of spreading two or three coats of clay for the purpose of keeping water in a vessel. This operation is also called puddling.

CLEAM. A term used in some places with the same signification as to stick or to glue. CLEAR. The nett distance between two bodies, where no other intervenes, or between their nearest surfaces.

CLEAR STORY OF CLERE STORY. The upper vertical divisions of the nave, choir, and transepts of a church. It is clear above the roof of the aisles, whence it may have taken its naine, but some have derived the name from the clair or light admitted through its tier of windows. Nearly all the cathedrals and large churches have clear stories, or tiers of arcades, and also of windows over the aisles and triforia. There is no triforium in the priory church of Bath, but a series of large and lofty windows constitute the clear story. The choir at Bristol Cathedral has neither triforium nor clear story. CLEATS. Small wooden projections in tackle to fasten the ropes to.

CLEAVING. The act of forcibly separating one part of a piece of wood or other matter from another in the direction of the fibres, either by pressure or by percussion with some wedge-formed instrument.

CLEFTS. The open cracks or fissures which appear in wood which has been wrought too green. The carpenter usually fills up these cracks with a mixture of gum and sawdust, but the neatest way is to soak both sides well with the fat of beef broth, and then dip pieces of sponge into the broth and fill up the cracks with them; they swell out so as to fill the whole crack, and so neatly as to be scarcely distinguishable, CLEOMENES. See ARCHITECTs, list of, 21.

CLEOPATRA'S NEEDLES. A name given to two obelisks on the east of the palace at Alexandria. They are of Thebaic stone and covered with hieroglyphics. One has been thrown down, broken, and lies buried in the sand. The other stands on a pedestal. They were each of a single stone, about sixty feet high and seven feet square. CLEPSYDRA. (Gr. from KAETT, to conceal, and 'Towp, water). A water clock, or vessel for measuring time by the running out of a certain quantity of water, or sometimes of sand, through an orifice of a determinate magnitude. Clepsydras were first used in Egypt under the Ptolemies; they seem to have been common in Rome, though they were chiefly employed in winter. In the summer season sundials were used.

CLINCHING. The act of binding and driving backward with a hammer the pointed end of a nail after its penetration through a piece of wood.

CLINKERS. Bricks impregnated with nitre and more thoroughly burnt by being nearer the fire in the kiln. See p. 504.

CLOACE. The name given to the common sewers of ancient Rome for carrying off into the Tiber the filth of the city. The chief of these, called the Cloaca Maxima, was built by the first Tarquin of huge blocks of stone joined together without cement. It consisted of three rows of arches one above another, which at length conjoin and unite together. It began in the Forum Romanum, was 300 paces long, and entered the Tiber between the temple of Vesta and the Pons Senatorius. There were as many principal sewers as there were hills in the city.

CLOAK-PINS AND RAIL. A piece of wood attached to a wall, furnished with projecting pegs on which to hang hats, great-coats, &c. The pegs are called cloakpins, and the board into which they are fixed, and which is fastened to the wall, is called the rail. CLOISTER, (Lat. Claustrum.) The square space attached to a regular monastery or large church with a peristyle or ambulatory round, usually with a covered range of building over. The cloister is perhaps, ex vi termini, the central square shut in or closed by the surrounding buildings. Cloisters are usually square on the plan, having a plain wall on one side, a series of windows between the piers or columns on the opposite side, and arched over with a vaulted or ribbed ceiling. It mostly forms part of the passage of communication from the church to the chapter house, refectory, and other parts of the establishment. In England all the cathedrals, and most of the collegiate churches and abbeys, were provided with cloisters. On the Continent they are commonly appended to large monasteries, and are often decorated with tombs and paintings in fresco.

A common appendage to a cloister was a lavatory, or stone trough for water, at which the monks washed their hands previous to entering the refectory. CLOSER. The last stone in the horizontal length of a wall, which is of less dimensions than the rest to close the row. Closers in brickwork, or pieces of bricks (or bats), less or greater than half a brick, that are used to close in the end of a course of brickwork. In English as well as Flemish bond, the length of a brick being but nine inches, and its width four inches and a half, in order that the vertical joints may be broken at the end of the first stretcher, a quarter brick (or bat) must be interposed to preserve the con

tinuity of the bond, this is called a queen-closer. A similar preservation of the bond may be obtained by inserting a three-quarter bat at the angle in the stretching course; this is called a king-closer. In both cases an horizontal lap of two inches and a half is left for the next header. See Book II. Chap. III. Sect. 2.

CLOSE STRING. In dog-legged stairs, a staircase without an open newel.

CLOSE OF CLOOS. See ARCHITECTS, list of, 153.

CLOSET. A small apartment frequently made to communicate with a bed-chamber, and used as a dressing room. Sometimes a closet is made for the reception of stores, and is then called a store closet.

CLOUGH OF CLOYSE. The same as paddle, shuttle, sluice, or penstock. A contrivance for retaining or letting out the water of a canal, pond, &c.

CLOUGH ARCHES or PADDLE-HOLES. Crooked arches by which the water is conveyed from the upper pond into the chamber of the lock of a canal on drawing up the clough. CLOUT NAILS. See NAILS.

CLUSTERED. The combination of several members of an order penetrating each other. CLUSTERED COLUMNS. Several slender pillars or columns attached to each other so as to form one. In Roman architecture the term is used to denote two or four columns which appear to intersect each other, at the angle of a building or apartment, to answer

to each return.

COARSE STUFF. In plastering, a mixture of lime and hair used in the first coat and floating of plastering. In floating more hair is used than in the first coat.

Солт. A thickness or covering of plaster or other work done at one time.

COBARRUBIAS. See ARCHITECTS, list of, 210.

COB-WALLS. Such as are formed of mud mixed with straw, not uncommon in some districts of England, but the best are to be found in Somersetshire,

COCCEIUS. See ARCHITECTS, list of, 38.

COCKING or COGGING. See CAULKING.

COCKLE STAIRS. A term sometimes used to denote a winding staircase.

CENACULUM. (Lat.) In ancient Roman architecture, an eating or supper room.

In the

carly period of their history, when the houses rarely consisted of more than two stories, it denoted generally the upper story. The word also signified lodgings to let out for hire, and also the upper stories of the circi, which were divided into small shops or

rooms.

CONATIO.

An apartment in the lower part of the Roman houses, or in a garden, to sup or eat in. From Suetonius it would appear that it denoted a banqueting and summer house. In the Laurentine Villa a large cœnatio is described by the younger Pliny, and it seems, from the description, that it was placed in the upper part of a lofty

tower.

COFFER. (Sax. Corne.) A sunk panel in vaults and domes, and also in the soffite or under side of the Corinthian and Composite cornices, and usually decorated in the centre with a flower. But the application of the term is general to any sunk panel in a ceiling or soffite.

COFFER DAM. A case of piling, water-tight, fixed in the bed of a river, for the purpose of excluding the water while any work, such as a wharf, wall, or the pier of a bridge, is carried up. A coffer dam is variously formed, either by a single enclosure or by a double one, with clay, chalk, bricks, or other materials between, so as effectually to exclude the water. The coffer dam is also made with piles only driven close together, and sometimes notched or dove-tailed into one another. If the water be not very deep, piles may be driven at a distance of five or six feet from each other, and grooved in the sides with boards let down between them in the grooves. For building in coffer dams, a good natural bottom of gravel or clay is requisite, for though the sides be made sufficiently water-tight, if the bed of the river be loose, the water will ooze up through it in too great quantities to permit the operations to be carried on. It is almost unnecessary to inculcate the necessity of the sides being very strong and well-braced on the inside to resist the pressure of the water.

COGGING. See CAULKING.

COIN. (Fr.) The same as quoin. The angle formed by two surfaces of a stone or brick building, whether external or internal, as the corner formed by two walls, or of an arch and wall, the corner made by the two adjacent sides of a room, &c.

COLE.

See ARCHITECTS, list of, 175.

COLISEUM. The name given to the amphitheatre built (a. d. 72) by Vespasian. See body of the work, p. 94.

COLLAR OF COLARINO. (It.) A ring or cincture; it is another name for the astragal of a column. It is sometimes called the neck, gorgerin, or hypotrachelium.

COLLAR BEAM. A beam used in the construction of a roof above the lower ends of the rafters or base of the roof. The tie beam is always in a state of extension, but the collar beam may be either in a state of compression or extension as the principal rafters are

with or without tie beams. In trussed roofs, collar beams are framed into queen posts; in common roofs, into the rafters themselves.

In general, trusses have no more than one collar beam; yet, in very large roofs, they may have two or three collar beams besides the tie beam. The collar beam supports or trusses up the sides of the rafters, so as to keep them from sagging without any other support, but then the tie beam would be supported only at its extremities. In common purlin roofing, the purlins are laid in the acute angles between the rafters and the upper edges of the collar beams. See p. 546.

COLLEGE. An establishment properly so termed for the education of youth in the higher branches of study. See Book III. Chap. III. Sect. 8.

COLONELLI. (It.) The Italian name for the posts employed in any truss framing. COLONNADE. (It. Colonnata.) A range of columns. If the columns are four in number, it is called tetrastyle; if six in number, hexastyle; when there are eight, octastyle; when ten, decastyle; and so on, according to the Greek numerals. When a colonnade is in front of a building it is called a portico, when surrounding a building a peristyle, and when double or more polystyle. The colonnade is moreover designated according to the nature of the intercolumniations introduced as follows: pycrostyle, when the space between the columns is one diameter and a half of the column; systyle, when it is of two diameters; eustyle, when of two diameters and a quarter; diastyle, when three, and aræostyle when four.

COLUMBARIUM. (Lat.) A pigeon-house. The plural of the word (columbaria) was applied to designate the apertures formed in walls for the reception of cinerary urns in the ancient Roman cemeteries.

COLUMELLE. A name sometimes used for balusters. COLUMN. (Lat. Columna.) Generally any body which supports another in a vertical direction. For an account of the columns used in the five orders, see Book III. Chap. I. Sects. 2, 3, 4, 5, 6, and 7. There are various species of columns, as twisted, spiral, and rusticated. Cabled or rudented columns are such as have their flutings filled with cables or astragals to about one third of the height. Carolitic columns have their shafts foliated. Columns were occasionally used as monuments, as the Trajan and Antonine columns at Rome, and the Monument in London. By the side of the Halle au Blè at Paris there is a gnomonic column for showing the time, erected by Catharine di Medicis. The Columna Bellica at Rome was near the temple of Janus, and at it the consul proclaimed war by throwing a javelin towards the enemies' country. The chronological column was rather historical, bearing an inscription to record an event. The cruciferal column is one bearing a cross; the funereal one, an urn; the zoophoric, an animal; and the itinerary one pointed out the various roads diverging from its site. There was among the Romans what was called a lacteal column, which stood in the vegetable market, and contained on its pedestal a receptacle for infants abandoned by their parents. (Juvenal, Sat. vi.) On the legal column were engraved the laws; the boundary or limitative column marked the boundary of a province; the manubial column was for the reception of trophies or spoils; and the rostral column, decorated with prows of ships, was for the purpose of recording a naval engagement. The triumphal column was erected in commemoration of a triumph, and the sepulchral one was erected on a tomb. The milliarium aureum, or milliary column of the Romans, was originally a column of white marble, erected by Augustus in the Forum, near the temple of Saturn. From it the distances from the city were measured. It is a short column with a Tuscan capital, having a ball of bronze (formerly gilt for its finish) at top, and is still preserved in the Capitol. COMBINATION OF THE PARTS OF BUILDINGS. See Book III. Chap. III. Sect. 1., and Book III. Chap. II. Sects. 4. and 6.

COMITIUM. (Lat.) A building which stood in the Roman Forum, wherein assemblies of the people were held. It occupied the whole space between the Palatine Hill, the Capitol, and the Via Sacra.

COMMISSURE. (Lat.) The joint between two stones, or the application of the surface of one stone to the surface of another.

COMMON CENTRING. Such as is constructed without trusses, but having a tie beam at its ends. Also that employed in straight vaults.

COMMON JOists. Those in single naked flooring to which the boards are fixed. They are also called boarding joists, and should not exceed one foot apart. COMMON RAFTERS.

Those in a roof to which the boarding or lathing is attached. COMMON ROOFING. That which consists of common rafters only, which bridge over the purlins in a strongly framed roof.

COMMUNICATION DOORS. Those which, when open, throw two apartments into one.

COMPARTED. (Fr. Compartir, to divide.) That which is divided into several parts is said to be comparted.

COMPARTITION. The distribution of the ground plot of an edifice into the various passages and apartments.

COMPARTMENT. A subdivisional part, for ornament, of a larger division. To this alone is the term properly applicable. COMPARTMEMT CEILING. One divided into panels, which are usually surrounded by

mouldings.

Beam

COMPARTMENT TILES. An arrangement of varnished red and white tiles on a roof. COMPASS SAW. One for dividing boards into curved pieces; it is very narrow and without a back. COMPASSES. (Fr. Compas.) A mathematical instrument for drawing circles and measuring distances between two points. Common compasses have two legs, moveable on a joint. Triangular compasses have two legs similar to common compasses, and a third leg fixed to the bulb by a projection, with a joint so as to be moveable in every direction. compasses, which see, are used for describing large circles. Proportional compasses have two pair of points moveable on a shifting centre which slides in a groove, and thereby regulates the proportion that the opening at one end bears to that of the other. They are useful in enlarging or diminishing drawings. COMPLEMENT. The number of degrees which any angle wants of a right angle. complement of a parallelogram is two lesser parallelograms, made by drawing two right lines parallel to the sides of the quarter through a given point in the diagonal. COMPLUVIUM. (Lat.) An area in the centre of the ancient Roman houses, so constructed that it might receive the waters from the roofs. It is also used to denote the gutter or eave of a roof.

COMPO. A name often given to Parker's cement.

COMPOSITE ARCH. The same as the pointed or lancet arch.

The

COMPOSITE NUMBERS. Such as can be divided by some other number greater than unity; whereas prime numbers admit of no such divisor.

COMPOSITE ORDER. See Book III. Chap. I. Sect. 7., and Book I. Chap. II. Sect. 13. COMPOSITION, ARCHITECTURAL. For general principles, see Book III. Chap. II. Sect. 1. COMPOSITION OF FORCES. The combination or union of several forces for determining the See p. 381. See p. 280. 856.

result of the whole.

COMPOUND INTEREST.

COMPRESSIBILITY. The quality of bodies which permits of their being reduced to smaller dimensions. All bodies, in consequence of the porosity of matter, are compressible, but liquids resist compression with immense force.

CONCAMERATA SUDATIO. An apartment in the ancient gymnasium, between the laconicum or stove, and the warm bath. To this room the racers and wrestlers retired to wipe off the sweat from their bodies.

CONCAMERATE: (Lat.) To arch over.

CONCAVITY. (Lat. Concavus, hollow.) Of a curve line is the side between the two points of the curve next its chord or diameter. The concavity of a solid is such a curved surface, that if any two points in it be taken, the straight line between them is in a void space, or will coincide in only one direction with the surface.

CONCENTRIC. (Lat.) Having a common centre, as are the radii of a circle. CONCHOID OF NICOMEDES. A name given to a curve invented by that mathematician for solving the two famous problems of antiquity - the duplication of the cube, and the trisection of an angle. It continually approaches a straight line without meeting it, though ever so far produced.

CONCRETE. (Lat. Concrescere.) To coalesce in one mass. A mass composed of stone chippings or ballast, cemented together through the medium of sand and lime, and usually employed in making foundations where the soil is of itself too light or boggy, or otherwise insufficient for the reception of the walls. See Book II. Chap. II.

Sect. 11.

CONDUIT. (Fr.) A long narrow walled passage underground, for secret communication between different apartments. It is a term also used to denote a canal or pipe for the conveyance of water, and is also applied to the structure to which it is conveyed for delivery to the public.

CONE. (Gr. Kavos.) A solid body, having a circle for its base, and terminating in a point called its vertex; so that a straight line drawn from any point in the circumference of the base to the vertex will coincide with the convex surface. If the axis or straight line drawn from the centre of the base to the vertex be perpendicular to the base, it is termed a right cone; if not, it is an oblique cone.

CONFESSIONAL. (Lat.) In Catholic churches the small cell wherein the priest sits to hear the confession of, and give absolution to, the penitent. It is usually constructed of wood and in three divisions, the central one whereof has a seat for the convenience of the priest.

CONFIGURATION.

The exterior form or superficies of any body.

CONGE'. (Fr.) The same as APOPHYGE, which see.

CONIC SECTIONS.

The figures formed by the intersections of a plane with a cone. They

are five in number: a triangle, a circle, an ellipse, a parabola, and an hyperbola; the three last, however, are those to which the term is usually applied. See Book II. Chap. I. Sect. 5.

CONICAL ROOF. One whose exterior surface is shaped like a cone.

CONISTERIUM. (Gr. Koviσrηpiov.) In ancient architecture, a room in the gymnasium and palæstra, wherein the wrestlers, having been anointed with oil, were sprinkled over with dust, that they might lay firmer hold on their antagonists.

CONJUGATE DIAMETERS. The diameters in an ellipsis or hyperbola parallel to tangents at each other's extremities.

CONOID. (Gr. Kovocions.) Partaking of the figure of a cone.

A figure generated by the revolution of a conic section round one of its axes. There are three kinds of conoids, the elliptical, the hyperbolical, and the parabolical, which are sometimes otherwise denominated by the terms ellipsoid or spheroid, hyperboloid, and paraboloid.

CONSERVATORY.

A building for preserving curious and rare exotic plants. It is made with beds of the finest composts, into which the trees and plants on being removed from the greenhouse, and taken from the tubs and pots, are regularly planted.

With respect to its construction, it is very similar to the greenhouse, but it must be more spacious, loftier, and finished in a superior style. The sides, ends, and roofs should be of glass, for the free admission of light, and for protection of the plants. It should be, moreover, seated on a dry spot, so as to receive during the day as much of the sun's heat as possible. It is to be provided with flues or boiling water pipes, to raise the temperature when necessary; there must also be contrivances for introducing fresh air when required. In summer time the glass roofs are taken off and the plants exposed to the open air; but these are restored always, if taken off, on the slightest indication of frost. The chief point in which conservatories differ from greenhouses is, that in the latter, the plants and trees stand in pots placed upon stages, whereas, in the former, they are planted in beds of earth surrounded with borders. See GREENHOUSE. CONSOLE. The same as ANCONES, which see.

CONSTRUCTION. Literally, the building up from the architect's designs; but amongst architects it is more particularly used to denote the art of distributing the different forces and strains of the parts and materials of a building in so scientific a manner as to avoid failure and insure durability. The second book of this work is devoted to the subjects involved in the science of construction. CONSTRUCTIVE CARPENTRY, or PRACTICAL CARPENTRY. See Book II. Chap. III. Sect. 4. CONTACT. (Lat. Contactus.) In geometry the touching any figure by a line or plane which may be produced either way without cutting it.

CONTENT. (Lat. Contentus.) The area or superficial quantity contained in any figure. CONTEXTURE. (Lat. Contextus.) The inter-disposition, with respect to each other, of the different parts of a body.

CONTIGNATIO. In Roman carpentry the same as that which we term naked flooring. CONTINUED. A term used to express anything uninterrupted. Thus, an attic is said to be continued when not broken by pilasters; a pedestal is continued when, with its mouldings and dado or die, it is not broken under the columns; so of a socle, &c. CONTOUR. (It. Contorno.) The external lines which bound and terminate a figure. CONTRACT. An agreement attached to a specification for the performance of certain works. CONTUCCIO. See ARCHITECTS, list of, 190.

CONVENT. (Lat. Conventus.) A building for the reception of a society of religious

persons.

CONVENTUAL CHURCH. One attached or belonging to a convent.

CONVERGENT LINES. Such as, if produced, will meet.

CONVEX. (Lat. Convexus.) A form which swells or rounds itself externally. A convex rectilinear surface is a curved surface, in which a point being taken, a right line passing through it can only be drawn in one direction.

COPING. (Dutch, Cop, the head.) The highest and covering course of masonry or brickwork in a wall. Coping equally thick throughout is called parallel coping, and ought to be used only on inclined surfaces, as on a gable, for example, or in situations sheltered from the rain, as on the top of a level wall, which it is intended to cover by a roof. Coping thinner on one edge than on the other serves to throw off the water on one side of the wall, and is called feather-edged coping. Coping thicker in the middle than at the edges is called saddle-backed coping. This, of course, delivers each way the water that falls upon it. It is commonly used on the walls of a sunk area, on dwarf walls carrying an iron railing, and in the best constructed fence walls. In Gothic architecture, coping is either inclined upon the faces or plumb; in the former case the sides of the vertical section are those of an equilateral triangle with an horizontal base. It is sometimes in

one inclined plane, terminated at top by an astragal, and at others in two inclined planes parallel to each other, whereof the upper is terminated at top by an astragal, and projects