Of all the kinds of intercolumniation, the custyle was in the most general re quest among the ancients; and though in modern architecture both the custvle and diastyle are employed, yet the former of these is still preferred in most cases ; as to the pycnostyle interval, it is frequently rejected for want of room, and the arxo style, for want of giving sufficient support to the entablature.
The moderns seldom employ more than one row of columns, either in external or internal colonades; for the back range destroys the perspective regularity of the front range : the visual rays, coming from both ranges, produce nothing but confu sion in the eye of the spectator. This confusion, in a certain degree, also attends pilasters placed behind a row of insulated columns; but in this the relief is strong er, owing to the rotundity of the column, and the flat surfaces of the pilasters. When buildings are executed on a small scale, as is frequently the case of temples, and of other inventions used for the orna ments of gardens, it will be found neces sary to make the intercolumniations, or at least the central one, broader than usual, in proportion to the diameter of the columns; for, when the columns are placed nearer each other than three feet, the space becomes too narrow to admit persons of a corpulent habit Pilasters and Ant,e. Pilasters are rec tangular prismatic projections, advancing from the naked part of a wall, with bases and capitals like columns, and with an entablature supported by the columns ; hence they differ from columns in their horizontal sections being rectangles, whereas those of columns are circles, or the segments of circles, equal to, or great er, than semicircles.
It is probable that pilasters are of a Roman inventon, since there are but few instances in Grecian buildings where they are repeated at equal or regular intervals, and these only in the latter ages of Greece, as in the monument of Philopapus, (un less in that of Thrasyllus); hut of their application in Roman works there are numberless instances : Vitruvius calls them parastatx. The Greeks used a kind of square pillars only upon the ends of their walls, which they called antx, which antx projected sometimes to a consider able distance from the wall of the princi pal front, and formed the pronaos or vestibulum. The breadth of the antx on
the flanks of the temples was always con siderably less than on the front : these anti had sometimes columns between them, and when this was the case, the return within the pronaos was of equal breadth to the front. The capitals of the antx never correspond with those of co lumns, though there are always some characteristic marks, by which the order may be distinguished.
Pilasters, or parastatx, when ranged with columns under the same entablature, or placed behind a row of columns, have their bases and capitals like those of the columns, with the corresponding parts at the same heights, and when placed upon the angles of buildings, the breadth of the returns is the same as that of the front. The trunks of pilasters have frequently the same diminution as the shafts of the columns, such as in the arches of Septi mius Severtis and Constantine, and in the frontispiece of Nero, and the temple of Mars the Avenger, at Rome ; in this case, the top of the trunks of the pilasters is equal to the breadth of the soffit of the architrave, and the upright face of the architrave resting on the capital, in the same perpendicular as the top of the pi laster. When the pilasters are undimi nished, and of the same breadth as the columns at the bottom, the face of the architrave resting on the capital retreats within the top of the trunk, as in the Pan theon of Agrippa.
Pilasters are either plain or fluted. IR ancient edifices this was not always regu lated by the columns, but perhaps de pended on the taste of the architects, or destination of the edifice. The columns are plane on the portico of the Pantheon, while the pilasters are fluted; and the contrary, on the portico of Septimius Se v6.us. When pilasters are fluted, the angles or quoins are frequently beaded, such as those of the pantheon, in order to strengthen the angles, and the flutes are generally of' a semicircular section. The faces of pilasters are sometimes sunk within a margin, and the pannels charged with foliage, arabesque or grotesque. or naments, or instruments of music and war, or sometimes these compounded, ac cording to the destined purpose of the place iu which they are employed.