ELEVATION may be defined to be the _upright plan_ of a building, or any part of a building, showing its exact form and dimensions as they actually exist; whereas in perspective the forms are shown not as they exist, or are in themselves, but merely as they appear to the eye, according to the station of the spectator. Elevations are of two kinds, viz. _geometrical_ and _perspective_. In the former, the whole is projected upon the same _plane_, the remote parts are shown of their full size, and distance can be expressed only by shadow thrown upon the second plane by parts in the nearest one; whereas Perspective elevation partakes of parallel perspective, and the parts beyond the first plane are shown diminished by distance, and also come into view, although they may be behind others on the first plane by which they would be concealed in a geometrical representation. For instance, supposing a portico to have a second row of columns in the same axes as those in front, that circumstance would not be at all apparent in a geometrical elevation, but could be understood only by means of the plan, the inner columns being concealed by those before them; but in a perspective elevation they would show themselves, as would also the ceiling and floor. ENTABLATURE.—The horizontal portion of an Order; the _trabeation_ or system of beams supported by the columns. There may, however, be entablature without columns,—where the latter are suppressed, as on the flanks of an _apteral_ temple; or omitted entirely, as in _astylar_ building. For the entablatures of the respective Orders, see pages 18, 41, 60.