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[NOTE. -- Further explanations, illustrations, &c., of many of the terms herein will be obtained in the Encyclopædia by reference to the Index; and many publications on the subjects described will be found in the List prefixed hereto.]

A. ABACISCUS. A word sometimes used as synonymous with abacus, but more correctly

applied to a square compartment enclosing a part or the entire pattern or design of a

Mosaic pavement. Abacus. (Gr. Alat, a slab.) The upper member of the capital of a column, and serving

as a crowning both to the capital and to the whole column. It is otherwise defined by some as a square table, list, or plinth in the upper part of the capitals of columns, especially of those of the Corinthian order, serving instead of a drip or corona to the capital, and supporting the nether face of the architrave, and the whole trabeation. In tho Tuscan, Doric, and ancient Ionic orders, it is a flat square member, well enough resembling the original title ; whence it is called by the French tailloir, that is, a trencher, and by the Italians credenza. In the richer orders it parts with its original form, the four sides or faces of it being arched or cut inwards, and ornamented in the middle of each face with a rose or other flower, a fish's tail, &c.; and in the Corinthian and Composite orders it is composed of an ovolo, a fillet, and a cavetto. The word is used by

Scamozzi tu signify a concave moulding in the capital of the Tuscan pedestal. ABATON. (Gr. Aßatov, an inaccessible place). A building at Rhodes, mentioned by

Vitruvius, lib. ii., entrance to which was forbidden to all persons, because it contained & trophy and two bronze statutes erected by Artemisia in memory of her triumph in sur

prising the city. ABATTOIR. (Fr. Abattre, to knock down.) A building appropriated to the slaughtering

of cattle. All private slaughtering-houses, in large towns at least, should be abolished, and public ones, under proper supervision, established, as lately effected at Edinburgh,

Manchester, and a few other towns. ABBEY. (Fr. Abbaïe.) Properly the building adjoining to or near a convent or monas

tery, for the residence of the head of the house (abbot or abbess). It is often used for tho church attached to the establishment, as also for the buildings composing the whole establishment. In such e-tablishments the church was usually grand, and splendidly decorated. They had a refectory, which was a large hall in which the monks or nuns had their meals; a guest hall, for the reception and entertainment of visitors ; a parlour or locutory, where the brothers or sisters met for conversation ; a dormitory, an almonry, wherefrom the alms of the abbey were distributed; a library and museum ; a prison for the refractory, and cells for penance. The sanctuary was rather a precinct than a building, in which offenders were, under conditions, safe from the operation of the law. Granges, or farm buildings, and abbatial residences. Schools were usually attached for the education of youth, with separate accommodations for the scholars; a singing school. A common room, with a fire in it, for the brothers or sisters to warm themselves, no other fire being allowed, except in the apartments of the higher officers. A mint for coining, and a room called an exchequer. The abbey was always provided with a churchyard, a garden, and a bakehouse. The sacristy contained the garments of the priests, and the vessels, &c. ; vestiaria or wardrobes being assigned for the monks. Many of the ordinary duties of these persons were performed in the cloisters where they delivered their lectures.


ABREUVOIR. (Fr.) In masonry, the joint between two stones, or the interstice to be filled

up with mortar or cement, when either are to be used. Absciss, or ABSCISSA. A geometrical term, denoting a segment cut off from a straight

line by an ordinate to a curve. ABsis. See APSIS. ABSORPTION. The penetration of a gas or liquid into any substance; or the taking up of

moisture by capillary attraction. A principle seriously affecting the durability of all building materials. The rapidity of absorption is not a criterion as t'» durability, but the comparative durability of stones of the same kind may be tested by the smallness of the weight of water which a given weight of stone is capable of absorbing. The actual absorption of water by bricks of various qualities has thus been stated :-Malm place brick, 62 ounces of water; white Surrey, 58 oz. ; white seconds, 52 oz. ; red facings, 51 oz.; pickings, 50 oz. ; stocks, 27 oz. ; Workman's waterproofed, 2 oz. The following table of the absorbent powers of certain stones, when saturated under the exhausted receiver of an air-pump is given in the Report of the Commissioners on Building Stones, 1839:

[blocks in formation]

The granites, though closely granulated, take up much more than the grauwacke, but less than the sandstones ; while the grauwacke resists the water four times that of

granite, and thirty-six times that of Yorkshire sandstones. ABSTRACT. A term in general use among artificers, surveyors, &c. to signify the collect

ing together and arranging under a few distinct heads the various small quantities of different articles which have been employed in any work, and the affixing of a price to determinate portions of each, as per square, per foot, per pound, &c. for the purpose of

more expeditiously and conveniently ascertaining the amount. ABUSE. A term applied to those practices in architecture which, arising from a desire

of innovation, and often authorised by custom, tend to unfix the most established principles, and to corrupt the best forms, by the vicious way in which they are used. Palladio has given a chapter on them in his work. He reduces them to four principal ones: the first whereof is the introduction of brackets or modillions for supporting a weight; the socond, the practice of breaking pediments so as to leave the centre part open ; third, the great projection of cornices; and, fourth, the practice of rusticating columns. Had Palladio lived to a later day, he might have greatly increased his list of abuses, as l'errault has done in the following list :--the first is that of allowing columns and pilasters to penetrate one another, or be conjoined at the angles of a building. The second that of coupling columns, which Perrault himself in the Louvre has made almost excusable; the third, that of enlarging the metopæ in the Doric order, for the purpose of accommodating them to the intercolumniations; the fourth, that of leaving out the inferior part of the tailloir in the modern Ionic capital; the fifth, that of running up an order through two or three stories, instead of decorating each story with its own or ler; the sixth, that of joining, contrary to the practice of the ancients, the plinth of the column to the cornice of the pedestal, by means of an inverted cavetto; the seventh, the use of architrare cornices ; the eighth, that of breaking the entablature

of an order over a column, &c., &c. ABU IMENT. The solid part of a pier from which an arch immediately springs. Abut

ments are artificial or natural : the former are usually formed of masonry or brickwork, and the latter are the rock or other solid materials on the banks of the river, in the case of a bridge, which receive the foot of the arch. It is obvious that they should be of

sufficient solidity and strength to resist the thrust of the arch. A BUTTALS. The buttings or boundings of land. ACANTHUS. (Akavdos, a spine.) A spiny herbaceous plant found in various parts of the

Levant. Its leaf is said by Vitruvius to have been the model on which the Grecian

architects formed the leaves of the Corinthian capital. ACER. A genus of trees comprehending the maple and sycamore, the wood of which is not

of much value. That of the acer campestre furnishes the cabinet makers with what

they call bird's-eye maple. ACCESS. See PASSAGE ; also Adir. ACCIDENTAL Point. In perspective, the point in which a straight line drawn from the

ese parallel to another straight line cuts the perspective plane. It is the point wherein the representations of all straight lines parallel to the original straight line concur

when produced. Its name is adopted to distinguish it from the principal point or point

of view. Acoustics. (Gr. Arouw, to hear.) The doctrine or theory of sounds, as applicable to

buildings. See THEATREs, book iii., chap. v., and Currches in the same book. The subject is one presenting great difficulty: The statements of various professors, and a comparison of buildings themselves, have been collected in a work by Mr. T. R. Smith. It was stated by Professor Lewis, at a lecture given in 1864-65, that in consulting one of the most eminent Scottish philosophers respecting the plan for a church, the reply was, that in his opinion the principle adopted would most probably answer ; but he added that he had studied acoustics probably as much as any man, and the conclusion he arrived at was that in applying theory to actual practice he knew nothing

about it, and he believed nobody else knew more. ACROPOLIS. (Gr. Arepos and nonis, city.) The upper town or citadel of a Grecian city,

usually the site of the original settlement, and chosen by the colonists for its natural


Fig. 1361. The Acropolis at Athens. strength. The most celebrated were those at Athens, Corinth, and Ithome; the two latter were called the horns of the Peloponnesus, as though their possession could

secure the submission of the whole peninsula. ACROTERIA. (Gr. Akpwrnprov, the extremity of anything.) The pedestals, often without

base or cornice, placed on the centre and sides of pediments for the reception of figures. Vitruvius says that the lateral acroteria ought to be half the height of the tympanum, and the apex acroterium should be an eighth part more. No regular proportion, however, is observable in Grecian buildings.

The word acroterium is applied to the ridge of a building; it has also been used to signify the statues on the pedestals; but it is only to these latter that it is strictly applicable. The word has, moreover, been given to the small pieces of wall in balustrades, between the pedestal and the balusters, and again to the pinnacles or other

ornaments which stand in ranges on the horizontal copings or parapets of buildings. Acute ANGLE. A term used in geometry to denote an angle less than 90°, that is, less

than a right angle. ACUTE-ANGLED TRIANGLE. A triangle having all its angles acute. Every triangle has at

least two acute angles. ADHESION. (Lat. Adhæreo.) A term in physics denoting the force with which different

bodies remain attached to each other when brought into contact. It must not be confounded with cohesion, which is the force that unites the particles of a homogeneous body with each other. The following is an account of some experiments recorded in the Technical Repository for 1824 :— The insertion of a nail is accomplished by destroying the cohesion of the wood, its extraction by overcoming the force of adhesion and friction. We will consider it here solely as a case of adhesion. Fine sprigs, of which 4560 weighed one pound, M of an inch long, forced four-tenths of an inch into dry Christiania deals at right angles to the fibre, required a force of 22 lbs. to extract them. The same description of nail having 3200 in the pound, ju of an inch long, and forced 100 of an inch into the same kind of wood, required 37 lbs. to extract it. Threepenny brads, 618 to the pound weight, one and a quarter inch long, forcod half an inch into the wood, required a force of 58 lbs. to draw them out. Fivepenny nails, 139 to the pound weight, two inches long, and forced one inch and a half into the wood, required a force of 320 lbs. to extract them. Sixpenny nails, 73 to the pound, two inches and a half long, and forced one inch into the wood, required 187 lbs. to extract them. The same kind of najl forced one inch and a half into the wood required 327 lbs. to draw it

out; and one forced two inches into the wood required 530 lbs. to extract it. In this last experiment the nail was forced into the wood by a hammer of cast-iron weighing 6:275 lbs. falling from a height of twelve inches, four blows of which were necessary to force the nail an inch and a half into the wood. It required a pressure of 400 lbs. to force the nail to the same depth. A sixpenny nail driven one inch into dry elm across the grain or fibres required 327 lbs. to draw it out by direct force; driven ondwise into dry elm, or parallel with the grain, it required only 257 lbs. to extract it. The same sort of nail driven into dry Christiania deal was extracted by a force equal to 257 lbs., and by one of 87 lbs. from a depth of an inch. The adhesion, therefore, of a nail driven into elm across the grain, or at right angles to the fibres of the wood, is greater than when it is driven with the grain, or parallel with the fibres, in the proportion of 100 to 78, or 4 to 3. And under the same circumstances. in dry Christiania deal, as 100 to 46, or nearly 2 to 1. The comparative adhesion of nails in elm and deal is between 2 and 3 to 1. To extract a sixpenny nail driven one inch into green sycamore required 312 lbs. ; from dry oak, 507 lbs.; and from dry beech, 667 lbs. A common screw of one-fifth of an inch had an adhesion about three times as great as that of a sixpenny nail. A common sixpenny nail driven two inches in dry oak would require more than half a ton

to extract it by pressure.' Adit (Lat. Adeo), or Aditus. The approach or entrance to a building, &c. Among

the ancients the aditus theatri, or adits of a theatre, were doorways opening on to the stairs, by which persons entered the theatre from the outer portico, and thence descended

into the seats. Upon the same principle were the adits of a circus. ADJACENT Angle, in geometry, is an angle immediately contiguous to another, so that one

side is common to both angles. This expression is more particularly applied to denote that the two angles have not only one side in common, but likewise that the other two

sides form one straight line. Avytum. (Gr. Adutov, a recess.) The secret dark chamber in a temple to which none

but the priests had access, and from which the oracles were delivered. Seneca, in his tragedy of Thyestes says

“Hinc orantibus Responsa dantur certa, dum ingenti sono

Laxantur adyto fata." Among the Egyptians the secos was the same thing, and is described by Strabo. The only well-preserved ancient adytum that has come to our knowledge is in the little temple at Pompeii; it is raised some steps above the level of the temple itself, and is

without light. ADZE or ADDICE. An edged tool used to chip surfaces in a horizontal direction, the

axe being employed to chop materials in vertical positions. The blade, which is of iron, forms a small portion of a cylindric surface, in both its sides, and has a wooden handle fixed into a socket at one of its extremities, in a radial direction, while the other extremity, parallel to the axis of the cylinder, and therefore at right angles to the handle is edged with steel, and ground sharp from the concave side. The adze is chiefly employed for taking off thin chips from timber or boards, and for paring away irregularities at which the axe cannot come. It is also usid in most joinings of carpentry, particularly when notched one upon another, scarfir gs, thicknesses of flooring boards

opposite to the joists, &c. AERIAL PERSPECTIVE. The relative apparent recession of objects from the foreground

owing to the quantity of air interposed between them and the spectator. It accompanies the recession of the perspective lines. Æsthetics. (Gr. AloOntikos, having the power of perception by means of the senses.) It

is in the fine arts that science which derives the first principles from the effect which certain combinations have on the mind as connected with nature and right reason. Seo

pp. 795 and 922. Ærtaiol. (Gr. Aetos, an eagle.) The name given by the Greek architects to the slabs

forming the face of the tympanum of a pediment. This word occurs in the Athenian inscription now in the British Museum, brought to England by Dr. Chandler, and relating to the survey of some temple at Athens. Æroma, or Æros. (Gr. Aetos.) A name given by the Greek architects to the tympanum

of a pediment. It seems derived from the custom of decorating the apex or ridge of the roof with figures of eagles, and that the name thence first given to the ridge was after

wails transferred to the pediment itself. Air Drains, or Dry AREAS. Cavities between the external walls of a building protected

by a wall towards the earth, which is thus prevented from lying against the said walls and creating damp. They may be made with the walls battering against the ground, and covered over with paving stones, or with their walls nearly perpendicular, and arched on the top. This covering should be above the ground, and sloped to throw off the wet. The bottoms should be pared, and the areas should be well ventilated.

Air HOLES. Holes made for admitting air to ventilate apartments : also for introducing

it among the timbers of floors and roofs for the prevention or destruction of the dry rot. AIR TRAP. A trap formed so as to prevent foul air from rising from sewers or drains

into the atmosphere. There are various sorts, all depending upon a certain amount of

water in them. Aisle, or AILE. (Lat. Ala.) A term chiefly used by the English architect to signify

the side subdivisions in a church, usually separated from the nare or centre division by pillars or columns. Among different nations, as applied to architecture, it bears different significations. Strabo states that among the Egyptians the ale of the temple were the two walls that enclosed tho two sides of the pronaos, and of the same height as the temple itself. The walls, lie observes, from above ground, were a little further apart than the foundations of the temple, but as they rose, were built with an inclination to each other. The passage, however, is not clearly to be understood.

In Gothic, as well as in many modern, churches, the breadth of the church is divided into three or five parts, by two or by four rows of pillars running parallel to the sides ; and as one or other is the case, the church is said to be a threeaisled or five-aisled fabric. The middle aisle is called the nare or chief aisle, and the penthouse, which joins to each side of the main structure containing the aisles, is called a wing. St. Mary's, Taunton ; Chichester Cathedra); St. Helen's, Abingdon ; and Elgin Cathedral, perhaps comprise all the fire-aisled churches in Great Britain, except a building at the west end of the cathedral at Durham. On the Continent there are many such buildings, among which is the cathedral at Milan. It is somewhat remarkable that in Westminster Abbey and in Redcliff Church at Bristol the aisles are continued on each side of the transept, and in Salisbury Cathedral on one side only, a circumstance not met with in any other churches in this

country. AJUTAGE. (Fr.) Part of the apparatus of an artificial fountain, being a sort of jet d'eau,

or kind of tube fitted to the mouth or aperture of a vessel, through which the water is

to be played, and by it determined into the form to be given to it. ALABASTER. A white semi-transparent variety of gypsum or sulphate of lime, a mineral

of common occurrence, and used for ornamental purposes, as screen work, and for sculpture. It was much used formerly for monuments in churches and the like, and has been

re-introduced of late years for similar purposes. ALBARIUM Opus. (Lat.) In ancient Roman architecture a term imagined by some to

hare been nothing more than a species of whitewash applied to walls, but, as we think, incorrectly. In the passage of the tenth chapter of the fifth book of Vitruvius, where he recommends the use of the albarium opus for the ceilings of baths, he allows tectorium opus as a substitute; so perhaps it was a species of stucco. Its employment at the baths of Agrippa, seems to prove it to have been superior to the other, and it is by no

means improbable that it was susceptible of a high polish. ALCOVE. A wide and deep recess in a room. That part of a sleeping chamber wherein

the bed is placed. The use of alcoves, though not by that name, is ancient. They were frequently designed in the form of a niche; such, for instance, as those that Winkelman notices at Harian's villa at Tivoli, of which sort are some at Pompeii. They were often formed by enclosures or balustrades, of various heights, and by means of draperies the alcove was separated from the large chamber of which it was a part. Some idea may be formed of it from many of the ancient bassi relievi, especially from the celebrated one known by the name of the Nozze Aldobrandini. In modern works this part of a room differs according to the rank and taste of the proprietor. In England it is rarely introduced, but in France and Italy it often forms a beautiful feature

in the sleeping apartments of palaces and large houses. ALDER. (Ang. Sax. Ellarn.) A tree belonging to the order Betulaceæ. It is used for

piling and any similar work under water. ALBATORIUM. In ancient Roman architecture, a room in which games at dice were

played. ALIPTERION. In ancient Roman architecture, a room used by the bathers for anointing

themselves, ALKORANES. In Eastern architecture, high slender towers attached to mosques, and

surrounded with balconies, in which the priests recite aloud at stated times prayers from the Koran, and announce the hours of devotion to worshippers. They much embellish the mosques, and are often very fantastical in form. They are also called

Minarets. ALLEY. (Fr. Allée.) An aisle, or any part of a church left open for access to another

part. In towns, a passage narrower than a lane. An enclosed walk in a garden. ALMERY or AUM BRYE. A recess or cupboard for holding the sacred vessels, &c., used in

the mase. An example, dating circa 1200, is seen in Lincoln Cathedral.

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