.Perlestale. A pedestal is a part of some buildings, with a base, surmounted with a rectangular prismatic solid, called the die, and this die again crowned with n cornice, for supporting a colonade, or pilastrade, or sometimes for supporting the upper part of a building as a ba.se ment. In the buildings of the Greeks pedestals never obtained : the columns of their temples generally stootl on the up. permost of three steps ; indeed, there is no existing example with any other num ber than three, except the' temple of Theseus at Athens, which had only two, and Was supposed to fhave been erected to an inferior deity : whatever innovations took place were after Greece lost its in dependence. The Romans, in many of their temples and other edifices, raised the floors so very high, that they were under the necessity of discontinuing the front stairs, which otherwise wonld have been found inconvenient, in occupying too much ground arca Ind the edifice ; and of adopting a pedestal, or podium, as a basement ; which was raised as high as the stair, and projected to the front of the steps which profiled on the sides of the pedestal.
It is remarkable, thatVitnivius, in treat ing of the Doric, Corinthian, and Tuscan orders, never mentions a pedestal: and in treating of the Ionic, he only speaks of it a.s -a necessary part of the construction, and lick as part of the order: several modern 'writers are also of this opinion.
It must be confessed, wherever pedes tals are introduced, the grandeur of the order is diminished, as all the parts are proportionably less; however, there are some situations, in which they are indis ponsably necessary, as in the interior of churches, where, if they were omitted, the beauty of the columns would be en tirely lost, as so great a portion of them would be concealed by- the pews. The proportions ofpedestals in the ancient Ro man buildings are very variable ; modern authors, however, have thought proper to bring them to a standard ratio, which Vignola makes one-third of the height of the column; but as this prcrportion ap peared to make them too high, Sir Wil liam Chambersreduced it tothree-tenths; these ratios, however, might vary as par ticular circumstances might require. The parts of pedestals may be thus propor tioned: divide the height into nine equal parts, give one to the cornice, two to the base, and six to the die. The plan of the die is the same as that of the plinth of the column : the projection of the cornice may be equal to its height : the base may be divided into three parts, giving two to the plinth, and one to the mouldings, which in most cases may project equal to their height These proportions are com mon to all pedestals. It is sometimes customary to adorn the dies of pedestals with sunk pannels, surrounded with moulding's : the pannels are frequently charged with bas reliefs or inscriptions. Projecting tablets should. never be ad mitted, as they are not only clumsy, but confuse the contour, The dies of the pe destals of the arches of Septimius Severus and Constantine have straight-headed niches, with statues. Pedestals should never be insulated, though the columns which stand upon them u-ere insulated.
ill the theatres and amphitheatres of the ancients,Pedestals were used in all the superior orders, while the inferior order stood upon steps. They were employed for the purpose of forming a parapet for the spectators to lean over, and for rais ing the base of the superior order so high, as to be seen upon a near approach to the building. In these situations the pedes tals were made no higher than to prevent accidents. When pedestals are continued with breaks under the columns, or pilas ters in ancient buildings, the breaks were called stylobatz ; and the recess between every two stylobatz, the podium, which had the seine parts disposed at the same levels as the stylobatz.
Arcades. An arcade is an aperture in a wall with an arched head; which term is also sometimes applied in the plural number to a range of apertures with arched heads. When an aperture is so large that it cannot be lintelled, it then becomes necessary to arch it over. Ar cades are not so magnificent as colonades, but they are stronger, more solid, and less expensive. In arcades the utmost care should be taken of the piers, that they he sufficiently strong to resist the pressure of the arches, particularly those at the extremes. The Romans employed them in their triumphal arches, and many other buildings. Arcades may be used with propriety in the gates of cities, of palaces, of gardens, and of parks ; they are much employed in the piazzas or squares of Italian cities; and, in general, are of great use, in affording both shade and shelter in hot and rainy climates; but, on the contrary, they are a great nuisance to the inhabitants, R. they darken their apartments, and serve to harbour idle and noisy vagabonds. Lofty arcades may be employed with great propriety in the courts of palaces, and noblemen's houses. There are various ways of decorating the piers of arcades, as with rustics, columns, pilasters, caryatides, petsians, or terms surmounted with appropriate entabla tures; and sometimes the piers are even so broad, as to admit of niches. The arch is either surrounded with rustic work, or with an archivolt; sometimes interrupted at the summit with a key-stone, in the form of a console, or marsh, or some other appropriate sculptured ornament. The archivolt rises sometimes from a plat band, or impost, placed on the top of the piers; and at other times from an enta blature, supported by columns on each side of the arch. In some instances the arches of arcades are supported entirely by single or coupled columns, without the entablature ; as in the temple of Faunus at Rome. This form is far from being agreeable to the eye ; it wants sta bility, as the columns would be incapable of resisting the lateral pressure of the arches, were they not placed within an other walled enclosure, er in a circular colonade. In large arches the key-stones should never be omitted, and should be carried to the soffit of the architrave, where they will be useful in supporting the middle of the entablature, which otherwise would have too great a bear ing.