are closed at the top, the apertures being always wide, are generally made with arched heads: the usual proportion of the arcade is that which has its height double to its breadth, or a trifle more.

The usual ornaments of gates are rustics of several kinds, such as columns, pilasters, entablatures, pediments, attics, blocking courses, imposts, archivolts, consoles, masks, niches, &c. In gates which are not closed at the top, the breadth of the piers may be from two-fifths to a quarter of their height, reckoning from the bottom of the plinth to the top of the cornice.

The rustics may either be plain, frosted, or vermiculated. The smallest width that can be given to the aperture of a gate is nine feet, which is but just sufficient for the free passage of coaches; but if waggons and loaded carts are to pass, it must not be less than ten or eleven feet, and if the gate is for the entrance of a city, it should not be of a less width than eighteen or twenty feet. The composition of gates should be characteristic of the place to which they are to open. Gates of cities and, fortresses should have the appearance of strength and majesty: their parts should be large, few in number, and of bold relief. The same ought likewise to be observed in the gates of parks, public walks, or gardens; these succeed better when composed of rustic work, and of the mas sive orders, than when they are enriched with nice ornaments or délicate profiles. However, triumphal arches, entrances to palaces, to magnificent villas, town or country houses, might with propriety be composed of the more delicate orders, and be adorned in the highest degree.

The gates of parks and gardens are commonly shut with iron folding grates, either plain or adorned: those of palaces should likewise be so, or else be left open all the day.

Niches. A niche is a recess in a wall, for the purpose of enshrining a statue or some other ornament, or as an ornament to the wall itself. Among the works of the Romans, niches have either that of a circular or rectangular plan: the heads of those which have circular plans are almost always spherical. In the middle of the attic of the piazza of Nerva, at Rome, there is a niche, with a rectangular elevation, and a cylindrical back and head: those upon elliptic plans were not much used by the ancients. In Wood's Ruins of Palmyra, there are, however, two exhibited with elliptic heads,

within the entrance portico of the temple of the Sun; but no plan is shewn. Niches, upon rectangular plans, have most frequently horizontal heads: there are a few to be found with cylindrical heads: those upon circular and rectangular plans are, for the most part, placed alternately, for the sake of variety. The plans of niches with cylindrical backs should be semicircular, when the thickness of walls will admit of it; and the depth of those upon rectangular plans should be the half of their breadth, or as deep as may be necessary, for the statues they are to contain: their heights depend upon the character of the statues, or on the general forms of groups introduced; seldom exceeding twice and a half of their width, nor less than twice. Niches for busts should have nearly the same proportion with regard to one another; their heights, in some cases, may be something more than their breadth. Some niches may be formed with cylindrical backs and spherical heads : some of them may be entirely formed with hemispherical backs; others of spheroidal backs, with the transverse or conjugate axis of the ellipsis vertical, as may be most suitable to the character of the thing to be enshrined: those with spheroidal backs may have their horizontal sections all circles of different diameters, and, consequently, their sections through the vertical axes, all equal semi-ellipses, similar to each other; or all their horizontal sections may be similar ellipses, and the sections through the vertical axis of the niche will be dissimilar ellipses of equal heights, at least for one half of the niche; but spheroidal niches with such sections are difficult to execute, and not so agreeable to the eye as those with circular horizontal sections. Niches for busts may be of any of these last forms, or of any other form used by the ancients.

Niches are susceptible of the same decorations as windows; and whether their heads be horizontal, cylindrical, or spherical, the inclosure may be rectangular. In the ruined edifices of antiquity, tabernacles are a very frequent ornament, and these often disposed with triangular and arched pediments alternately: the character of the architecture should be the same as that which is to be placed in the same range with them. Niches are sometimes disposed between columns and pilasters, and sometimes ranged alternately in the same levels with windows: in either case they should be ornamented or plain, as the space will admit,

If the intervals between the columns or pilasters be very narrow, the niches will be much better omitted, than to make them either diminutive, or of a disproportionate figure. When they are ranged with windows, their dimensions should be the same as the aperture of the windows. Niches being intended as repositories for statues, vases, or other works of sculpture, must be contrived to set off the things they are to contain to the best advantage, and therefore no ornaments whatever should be introduced; the body and head of the niche being as plain as possible: every kind of ornament, whether mouldings or sculpture, tends to confuse the outline.

Statues. Besides decorations of mouldings, columns, and pilasters, architecture is indebted to sculpture for a great part of its magnificence; and as the human body is justly esteemed the most perfect original, it has been customary, in every period, to enrich different parts of buildings with representations thereof. Thus the ancients adorned their temples, basilicos, baths, theatres, and other public structures, with statues of their deities, philosophers, heroes, orators, and legislators; and the moderns still preserve the same custom, placing in their churches, palaces, houses, squares, gardens, and public walks, the busts and statues of illustrious personages; or bas reliefs and groups, composed of various figures, representing memorable occurrences, collected from the histories, fables, or traditions of particular times. Sometimes the statues or groups are detached, and raised on pedestals, and placed contiguous to the walls of buildings, by flights of steps or stairs, at the angles of terraces, in the middle of rooms, or of courts, and public squares, but most frequently they are placed in niches. The size of the statue depends upon the dimensious of the niche: it should neither be so large as to seem crammed into it, nor so small as to be lost in it. The distance between the outline of the statue and the sides of the niche, should never be less than one-third of a head, nor more than the half, whether the niche be square or arched; and when it is a square, the distance from the top of the head to the soffit of the niche should not exceed the distance left on the sides. The statues are generally raised on a plinth, the height of which may be from one-third to one-half of the head; and sometimes, where the niches are very large, in proportion to the architecture they accompany, as may

be the case where an order comprehends but one story. The statues may be raised on small pedestals to a proper height, and by this means, the figure will not only have a better proportion to the niche, but also to the order, to which it would otherwise appear too trifling. Statues are not only placed in niches, but they are also placed on the tops of walls, and before the dwarf pilasters of attics, as in the arch of Constantine, and the Corinthian colonade at Thessalonica.

If there are two rows of niches in the same building, care must be taken to keep the statues of their proper attitudes. The character of the statue should always correspond to the architecture with which it is surrounded. Thus, if the order be Doric, Jupiter, Hercules, Pluto, Neptune, Mars, Esculapius, or any male figures, representing beings of a robust and grave nature, may be introduced. If Ionic, then Apollo, Bacchus, Ceres, Minerva, Mercury and if Corinthian, Venus and the Graces, Flora, or others of a delicate kind and slender make, may very properly have place.

Proportions of rooms. The proportions of rooms depend much on their use and dimensions; but with regard to the beauty, all figures from the square to a sesquilateral, may be employed: some have even extended the length of the plan to double its breadth, but this disparity of dimensions renders it impossible to proportion the height to both length and breadth, though galleries are frequently three, four, or even five squares in length; but as the eye only takes in a portion of this length, the comparison is merely made in respect of the breadth. The height of rooms depends upon the dimension of their plans and the form of the ceilings. In rooms with flat ceilings, if their plan be a square, their height may be from two-thirds to five-sixths of the side; and if an oblong, it may be equal to the width. In coved rooms, if the plan be a square, the height may be equal to the side; if oblong, it may be equal to the breadth only: or with a fifth, a quarter, or a third of the difference of the length and breadth. In galleries, the height may be from one and a third, to one and threefifths of the breadth. These are the gene ral relative dimensions of rooms, but good proportions are not always attainable, particularly in houses of great magnitude: sincé the same common height is that of all the rooms, whatever be the difference of their

plans with regard to their size; however, to keep the best possible proportions, the principal rooms may have flat ceilings, and the middle-sized ones may be reduced by coving the ceilings with a flat in the middle; or by groins, or domes, as may answer their heights but if the loftiest of these coved figures leaves still too great a height, recourse must be had to mezzanines; which are not only necessary for this purpose, but may always be employed with advantage, as they afford servants lodgings, baths, powdering-rooms, wardrobes, and other conveniences. All rooms of inferior classes may have mezzanines or intersoles.

In buildings where beauty and magnificence are preferred to economy, the halls, and galleries may be raised, making them occupy two stories. Saloons are frequently raised three stories, or the whole height of the building, and have galleries around their interior at the height of the floors, for communicating with the various parts of the building.

When rooms are adorned with an entire order, the entablature may occupy in height from one-sixth, to one-seventh of that of the room; if the entablature be without columns, it may have from one-seventh to one-eighth. If a cornice, frize, and astragal are executed, its height may be equal to a tenth; and if only a cornice, its height may be from a twentieth to a thirtieth part of that of the room. In general, all interior proportions and decorations must be less, and more delicate than those of the exterior. Architraves in most cases, should not be above one-seventh of the width.

Ceilings. The figures of ceilings are either flat or coved: coved ceilings either have a concavity around the margins, and are flat in the middle, or have a vaulted surface. (See VAULTS). Ceilings that are coved and flat, may occupy from one-fifth, to a fourth part of the height of the room: the principal sections of vaulted ceilings may be of various segments, equal to, or less than semicircles, as may be most suitable to the height of the room. Flat ceilings are adorned with large compartments, or foliages, and other ornaments, or with both. Compartment ceilings are either formed by raising mouldings on the surface, or by depressing the pannels within a moulded inclosure, which may be partly raised upon, and partly recessed within the framing, or entirely recessed: the figures of the pannels may either be polygonal, circular, or elliptical. The ceilings of the porticos and

of the interior of ancient temples are comparted, and the pannels deeply recessed; the prominent parts between them representing the ancient manner of framing the beams of wood which composed the floors; the mouldings on the sides of the pannels are sunk, by one, two, or several degrees, like inverted steps, and the bottoms of pannels are most frequently decorated with roses; the figures of these compartments áre mostly equilateral, and equiangular. Triangles were seldom used, but we find squares, hexagons, and octagons in great abundance. The framing around the pannels in Roman antiquity is constantly parallel, or of equal breadth, therefore when squares are introduced, there is no other variety; but hexagons will join in contiguity with one another, or form the interstices into lozenges, or equilateral triangles. Octagons naturally form two varieties, viz. that of their own figure, and squares in the interstices: this kind of compartment is called coffering, and the recessed parts coffers, which are used not only in plain ceilings, but also in cylindrical vaults. The borders of the coffering are generally terminated with belts, charged most frequently with foliage; and sometimes again the foliage is bordered with guillochis, as in the temple of Peace at Rome. In the ceiling of the entire temple at Balbec, coffers are disposed around the cylindrical vault, in one row rising over each intercolumn; and between every row of coffers is a projecting belt, ornamented with a guillochi, corresponding with two semi-attached columns in the same vertical plane, one column supporting each springing of the belt. The moderns also follow the same practice in their cupolas and cradle vaults, ornamenting them with coffers and belts: the belts are ornamented with frets guillochis, or foliages; small pannels are ornamented with roses, and large ones with foliage, or historical subjects, in a variety of different man

ners.

The grounds may be gilt and the ornaments white, partly coloured, or streaked with gold; or the ornaments may be gilt and the grounds white, pearl, straw-colour, light-blue, or any tint that may agree best with the ornaments. Some ceilings are painted either wholly, or in various compartments only: when a ceiling is painted in representation of a sky, it ought either to be upon a plane or spheric surface. A ceiling coved and flat, with the plane painted to represent the sky, is extremely

improper, as the cove represents the half of an arch upon every side of the room; it will seem as if falling, from the want of an apparent support in the middle, unless the ceiling rise from a circular plan. Ceilings coved and flat are much employed in modern apartments: they seem to be a kind of medium between the horizontal, and the various arched forms practised by the ancients they do not require so much height as the latter, but they are neither so graceful nor so grand. Vaulted ceilings are more expensive than plane ones, but they are also susceptible of a greater variety of embellishments.

Chimnies. A chimney is an opening through a wall upwards, beginning at one side of a room, and ending at the top of a wall: its use is to warm the room, and give passage to the smoke. That part of the opening which faces the room is the place where the fire is put, and consequently is called the fire-place: the tube or hollow proceeding from the fire-place upwards, for giving vent to smoke, is called the funnel, or flue: the stone or marble laid level with the floor immediately before the fire-place is called the hearth or slab; and the one under the fire-place the back or inside hearth. The projecting parts of the walls on each side of the fire-place, forming also parts of the surface of the room, and standing at the extremities of the hearth, are called jambs: the head of the fire-place in the surface of a room, resting upon the jambs, is called the mantle: the mantle, and that part of the chimney resting upon it, forming a part of the side of the room, and also the whole side of the flue to the top, is called the breast; the side of the flue opposite to the breast is called the back; and the sides of the fire-place contained between the jambs and the back are called covings. When there are two or more chimnies in the same wall, the flues of which approach very near to each other, the thin division which separates one flue from another is either called a partition or a with; that part of the opening or horizontal section opposite to the mantle of a fire-place is called the throat; and that turret above the roof of a house, containing one or more flues, is called the shaft.

In stone walls the most common dimensions of the sections of flues are from 12 to 13 inches square, for fire-places about 3 feet wide in front; and those in brick walls 14 inches by 9 inches. The area of the section of the flue should always be propor

tioned to the area of the fire usually put in the fire-place, that is, nearly equal to the area of the horizontal section of the fire itself, excepting at the throat. The throat should be immediately over the fire, and its horizontal dimension in the thickness of the wall should not exceed 44, or 5 inches at most. The fuel grate, or stove, should be brought as near to the throat as conveniency may require. The coving should be placed bevelling nearer together at the back than at the jambs, making an exterior angle with the front of the jambs, and an interior angle with the back, of 135 degrees each. The back and covings forming the sides of the fire-place should be of white materials, such as white stone, or brick covered with plaster, which are most conveniently put up after the house is built. Most metals are unfavourable for this purpose. The top of the throat should be quite level, forming an abrupt plane. Some of the principles in the construction of chimnies are very well ascertained, others are not easily discovered till tried. The more the air that goes into the flue is rarefied, with the more force it will ascend, and the higher the flue the greater also will this force be; therefore the fire should have as little vacancy on either side as possible, and the flue, when convenient, should be carried as high as possible, and not have too wide an aperture at the top. The situation of doors in a room, the grate being placed too low, and other things, often occasion smoke; but whatever be the cause of it, if once discovered, the evil may easily be remedied. Circular flues are more favourable for venting than those whose sections are rectangular.

Vaults. A vault is an interior roof over an apartment, rising in a concave direction from the walls which support it, either meeting the vertex in a point or line, as when the section of the arch is Gothic; or one continued arch from the one abutment to the other, as when the section is a semicircle, or a segment less than a semicircle.

The vertical sections of the intradoes of vaults may be formed by an infinite variety of curves; but the most elegant forms are either circular or elliptic, which forms of sections have been generally adopted by the ancients of remote antiquity, by our ancestors throughout the middle ages, and by European nations at the present day. We shall therefore confine ourselves to those vaults which have their extradoes of circular and elliptic sections.

A cylindrical vault is a plain vault, the

figure of the extrados of which is a portion of a cylindric surface, terminating on the top of the walls which support it in a horizontal plane, parallel to the axis of the cylinder. This is also called a cradle vault.

A cylindroidal vault is a plain vault, the figure of the extrados of which springs from a horizontal plane; its section perpendicular to those lines is every where a semi-ellipsis, equal and similar throughout, and its base is that of either axis; or it is sometimes a segment of an ellipsis, less than a semi-ellipsis, having an ordinate parallel to the axis for its base.

A dome may be defined to be a vault rising from a circular, elliptical, or polygonal plan or base, such that all horizontal sections of the intrados are similar figures, having their centres in the same vertical line or axis, and such that the plans of any two sections may have the sides of similar inscribed figures parallel to each other, or that the figures of these plans may be concentric. If the dome is a portion of a sphere, that is, if its base be a circle, and its vertical section through the centre of its base the segment of a circle, then it is also called a cnpola.

When the portion of a sphere, or cupola, springs from a wall on a polygonal plan, and the vertical axis of the sphere passes through the middle of the plan, then the spandrels, or triangular spheric portions, comprehended between the springing lines and a horizontal plane passing through the different summits of the walls, are called pendentives.

When two or more plain vaults penetrate or intersect each other, the figure of the intrados formed by the several branches is called a groin, or cross vault.

When two opposite equal branches meet other two opposite equal branches in two intersecting vertical planes, passing through the diagonal lines, joining the four exterior angles of the plane, the groin may be called an equal pitched quadrilateral groin.

If two opposite branches of an equal pitched groin have cylindrical intradoes, and their plan of less breadth than that of the other two branches, the groin may be called cylindro-cylindroidal, or cylindroidocylindric groin, according as the cylindric branches or the other two are of the greatest breadth.

When a groin consisting of four branches is made by two equal portions of cylindric surfaces, with the axis of the one cutting

that of the other, it is called an equal-pitched cylindric groin.

When two opposite branches of a cylindric groin are of less breadth than the other two, it may be called un unequal pitched cylindric groin. This is called by workmen a Welsh groin.

When the branches of a cylindric groin are of equal breadth in the plan, the groin may be called an equilateral cylindric groin.

It is not easy to give a geometrical definition that will extend to all properties of vaulting, called by writers of the first eminence, groins. The first given is almost universal. It applies not only to plain vaults intersecting each other, but also to those that are annular, or in the form of semi-cylindric rings, intersected by cylindric or cylindroidal plain vaults, the axis of which tends to that of the annulus. It does not, however, comprehend that species used in King Henry VII.'s chapel, Westminster, and King's College chapel, Cambridge.

This species of groins, instead of the horizontal sections of the curved surfaces presenting exterior right angles, as is generally the case, present convex arches of circles. There is yet one property that is common to every species of groins, that is, the several branches intersect and form arches upon each inclosing wall, and the perpendicular surface of the wall upon each side is continued till it is intercepted by the entrados of the arches; consequently the upright of each wall is equal in height to the summit of the arches. Hence the difference between groins and domes. A groin is a branched vault, and each branch terminates against the enclosing walls; whereas a dome is a vault without branches, and the curves spring from the wall, or walls, from all points around its bottom circumference, whether the walls stand upon a polygona!, circular, or elliptic plan.

The Greeks, it would appear, had few or no arches or vaults much prior to the reign of Augustus, from which time they sometimes employed plain vaults with cylindrical intradoes; we also find that they used quadrilateral, equal-pitched groined vaults, with cylindrical or cylindroidal intradoes, or mixed of both, over the passages of the theatres and gymnasia.

The Romans, as would appear also, did not employ vaults more carly than the Greeks. The Pantheon, one of the earliest remaining structures with arches, was probably built by Agrippa, the son-in-law of