Attics.—Among the Athenians, it was a rule to con ceal the roofs of their buildings, for which purpose they crowned their cornices with low square pillars, of a form nearly approaching that of a pedestal, which have obtain ed the appellation of attics, from the country in which they were first, or chiefly employed, though no remains arc now to be discovered among the ruins of the ancient city of Athens.
Roman attics are to be seen in the remains of the tri umphal arches, and in the piazza of Nerva. In the arch of Constantine, the columns are surmounted with pedestals, as high as the base of the attic, upon which are placed insulated statues. At Thessalonica, there is an attic over a Corinthian colonnade, with breaks form ing dwarf pilasters over the columns, as in the arch of Constantine. The attic which is carried round the two courts of the great temple of Balbec, is also broken into dwarf pilasters over the columns and pilasters of the or der; which dwarf pilasters are surmounted with block ing courses, wherein statues are supposed to have stood.
In all these remains, the attics are disproprtional ; some of them being nearly one half of the height of the order. The moderns make their height equal to that of the entablature ; and the proportion of that of the mem bers may be regulated as in the case of pedestals.
Aricheg.—These decorations consist of recesses in a wall, either for the purpose of embellishment, or for re ceiving statues or other ornaments. They may be form ed with spherical heads, and cylindrical backs, or entire ly with hemispherical backs, or with spheroidal backs, having the transverse or conjugate axis of the ellipses as may best comport with the character of the object to be placed therein. Those with spheroidal backs may have their horizontal sections in circles of different diameters, and consequently, their sections through the vertical axis, 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 arc difficult of execution, and more pleasing to the eye than those with circular horizontal sections. Among the works of the Romans, niches have either a circular or rectangular plan; the heads of those of the circular kind are generally spherical. In the middle of
the attic of Nerva, at Rome, a niche is seen a rec tangular elevation, and a cylindrical back at I head. Those upon elliptic plans were not much used by the an cients; though in Wood's " Ruins of Palmyra," there are two niches with elliptical heads, within the entrance portico of the Temple of the Sun ; but the author has given no plan of them. Most frequently, those upon rectangular plans, have horizontal heads, though a few are to be met with that have cylindrical heads : those upon circular and rectangular plans, arc, for the sake of variety, most commonly placed alternately.
The plans of niches with cylindrical backs, should be semicircular, when the thickness of the 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 form of groupcs introduced, yet seldom ex ceeding twice and a half their width, nor being less than twice. Those for busts only, should have nearly the same proportion in respect to each other. In some cases their height may rather exceed the measure of their breadth : they may be of any of the forms used by the ancients, or of those mentioned at the beginning of this article.
In point of decorations, niches admit of all such as are applicable to windows; and whether their heads be ho rizontal, cylindrical, or spherical, the enclosure may be rectangular. In antique remains, we frequently meet with tabernacles as ornaments, disposed with alternate and arched pediments; the character of the architecture should be similar to that placed in the same range with them.
Niches are sometimes disposed between columns and pilasters, and sometimes ranged alternately, in the same level with windows : in either case they may be orna mented in plain, as the space will admit, but in the lat ter, they should be of the same dimensions with the aper ture of the windows. When the intervals between the columns or pilasters happen to be very narrow, niches had better be omitted, than have a disproportionate figure, or be of a diminutive size.