The name of ceiling (sec Plate CNC.) is given to the work which conceals the naked timbers of the roof of an apartment. The Normans generally left the framing timbers uncovered, and ornamented them with mould ings and sculptures ; but however much ornamented, they, in that state, always retained the name of roof. The Romans covered their roofs, and it is from the re mains of their public buildings, that the moderns, after the revival of that style, derived their manner of con structing ceilings. Ceilings are or coved, or partake of both. Flat ceilings are (bridled into large compartments, ornamented NI ith foliage or other devices. Coved ceilings have their sections either less than, or equal to semicircles. Ceilings which arefat and coved, are of modern invention ; they have their middle part flat, and that next the walls coved. Compartment ccil ings arc constructed either by raising the mouldings above d- general surface, or by sinking the pannels be low it ; or they may be partly raised and partly sunk. Amongst the ancients we find the paunch in squares, hexagons, and octagons ; triangles were rarely used.
In the porticos of ancient temples the ceilings were mostly divided into equilateral equiangular parts ; the pannels were deeply recessed, and the prominent sur faces represent the antique method of framing the beams of flours; the mouldings, on the sides of the 'minds, were like inverted steps, in one or more degrees frequently enriched, and the bottom of the pannels, in general, decorated with roses. In Roman works, the pannels are always parallel, or of equal breadth, which admits of no other variety, when squares arc introduced ; but hexagons will join w ith each other, or the interstices will form lozenges or equilateral triangles ; octagons form two varieties, viz. that of their own figure, and that of the square in their interstices. This sort of com partment is termed coffering, and the recessed parts are called coffers, which are used in vaulted or plain ceilings. The borders of the coffering is generally terminated by belts charged with foliage, and bordered with guillochis, as in the Temple of Peace at Rome. In the ceiling of the Temple of Ilalbec, coffers are disposed around the cylindrical vaults in rows, one row rising over each inter column ; and a projecting belt ornamented with a guil lochi between every row of coffers, corresponding to two semi-attached columns in the same vertical plane, which support the springing of the belt. This practice has been imitated by the moderns, in cupolas and cradle vaults ; the latter decorated by frets, guillochi, foliage, small pannels with roses, and large Li:muck with historical subjects, frequently in bold relief.
The grounds of compartment ceilings may be gilt, and the ornaments white, party coloured, or streaked with gold ; or vice versa, the ornaments may be gilt, and the grounds white pearl, straw coloured, blue, or any tint that will suit the ornaments. In some cases, the ceilings are either painted wholly, or in various com partments The mode of constructing the modern ceilings having been copied from the remains of ancient public buildings, it, in general, proved too heavy for the apartments of pri% ate dwellings. This defect was first remedied by
the delicate taste of Mr Adam, who introduced a much lighter style, more diversified, and better suited to pri vate apartments. The pannels were formed by slender mouldings, and decorations of elegant stucco ornaments, or painted deices; and the whole grounds also painted to relic% e the other decorations.
STAlus form the means of communication between the different stories. They are regulated in height and breadth so as to render the step commodious, and the length is suited to the magnitude of the edifice and the purpose to which it is to be appropriated. The average height is about six inches, the breadth 12 inches, and the length is seldom less than three feet, generally more. The space in which the steps are inclosed, is termed staircase, and is square, circular, elliptical, or triangu lar, but rarely polygonal. The steps may be constructed of marble, freestone, wood, &e.; they may be supported at both ends, or at one only ; when the latter, it is usually the broadest, though in small wooden stairs, the steps are sometimes made to project from a newel to which the narrow ends are fixed.
In the construction of stone stairs, supported at each end, the inner end of the steps may either be fixed into a solid newel, or be tailed into a wall surrounding an open one ; or where elegance is not an object, if the newel do not exceed two feet and a half, the steps may he support ed by a solid pillar, though when the newel is thicker, it will he cheaper to surround the open space with a thin wall. In stairs of a sunk story, where there is a geome trical stair above, the steps, next the newel, are gene rally supported on a dwarf wall.
Geometrical stairs have their outer ends fixed in the wall, and the under edge of every step supported by the edge of the one below it; being constructed with sally formed joints, so as to prevent them from descending in either the inclined direction of the stairs, or in a vertical direction. The upper sally of every step forms an in terior obtuse angle, called a back rebate, and the lower sally forms an exterior one ; the joint occasioned by these sallies, is called a joggle. The upper part of the joint may be level from the face of the riser to about one inch within the joint; the plane of the tread of each step is thus continued about an inch within the surface of each riser ; the lower part of the joint has a narrow surface perpendicular to the rake of the stair at the end next the newel. In stairs, constructed of most kinds of stone, the thickness of every step, at the thinnest part of the end next the newel, need not exceed two inches, for steps of four feet in length, measuring from the interior angle of every step perpendicular to the inclination. Their thick ness at the interior angle should be proportioned to their length ; allowing two inches for the thickness of the in ternal angle at four feet ; the thickness of every other stair, at the same place, will be equal in inches to half the length in feet ; thus, a step five feet lung will re quire to be two and a half inches in thickness at the in terior angle.