Gates. A gate is an aperture in a wall, which serves for the passage of horse men and carriages. They are employed as inlets to cities, fortresses, parks, gar dens, palaces, and all places to which there is a frequent resort of carriages. In gates which are closed at the top, the apertures being always wide, are general ly made with arched heads : the usual proportion of the arcade is that which has its height double to its breadth, or a tri fle more.
The usual ornaments of gates are rus tics of several kinds, such as columns, pi lasters,_ 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, reckon. ing from the bottom of the plinth to the top of the cornice.
The rustics may either be plain, frost ed, or vermiculated. The smallest width that can be given to the aperture of a gate is nine feet, which is but just sufficient for (lie 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 composi tion of g-ates should be characteristic of the place to which they are to opcn. Gates of cities and fortresses should have the appearance of strangth and majesty ; their parts should be large, few in num ber, and of bold relief. The same ought likewise to be observed in the gates of parks, public walks, or gardens; these suc seed better when composed of rustic work and of the massive orders, than when they are enriched with nice ornaments or delicate profiles. However, triuniphal arches, entrances to palaces,•to'mnifi cent 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 plane or adorned : those of palaces should likewise be so, or else be left open all the day.
Niches. A niche is a recess in s 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 al most always spherical. In the middle of
the attic of the piazza of Nerva, Rome there is a niche, with a rectangular eleva tion, 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 ex hibited, with elliptic heads within the en trance portico of the temple of the Sun ; but no plan is sliewn. Niches upon rec tangular plans have most frequently horizontal heads : there are a few to be found with cylindrical he ads : those upon circular and rectangulai plans are, for the most part, placed alternately., for the sake of variety. The plans of niches with cv lindrical backs should be semicirculir, tylten the thickness of walls will admit of it ; andthe depth of those upon rectangu • lar plans should be the half of their breadth, or a.s 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 g-roups introduced ; seldom exceeding twice and a half of their width, nor les than twice. Niches for busts should have nearly the same proportion with regard to one ano ther; their heights, in some cases, may be something more than their breadth. Zorn e niches may be formed with cy lindrical backs and spherical heads ; some of them may be entirely formed with hemispherical backs ; others of spheroi dal backs, with the transverse or conju gate axis of the elipsis vertical, as may be most suitable to the character of the thing to be enshrined : those with sphe roidal backs may have their horizontal sections all circles of different diameters, and, consequently, their sections through the vertical axes all equal semi-ellipse% similar to each other ; or all their horizon tal 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 v.-ith such *sections are difficult to execute, and not so agreeable to the eye 3-9 those with cir cular horizontal sections. Niches for busts may be of any of these last forms, or of any other form used by the an cients.