ENTASIS.—A slightly convex curvature given in execution to the outline of the shaft of a column, just sufficient to counteract and correct the appearance, or fancied appearance, of curvature in a contrary direction (_i. e._ concavely), which might else take place and cause the middle of the shaft to appear thinner than it really is. Entasis is therefore nothing _positive_: it is not intended to show itself, for were it to do so,—were there to be any visible swelling,—it would be a deformity; yet such deformity has been studiously adopted by many Modern Architects, merely, it would seem, for the sake of making evident that at all events they took pains to guard against an imaginary defect. The subject of entasis has been made one of those _nugæ difficiles_ which those who can do nothing else make great parade with. To such, then, be left all such sublimated transcendental niceties. If a column only 30 or 40 feet high would appear thinner in the middle than it really is, unless there made somewhat thicker than it would be were its profile a straight line, the same appearance would take place in any other lofty object, and in a greater degree in proportion to actual height; so that a tower of great loftiness, both positively and proportionally, _ought_—unless entasis were given it, to look thinner in the middle than at top and bottom. If such appearance really does take place, it is one perfectly in accordance with the laws of vision, therefore no more than a natural and perfectly proper one. In all such cases the judgment corrects the eye, and prevents mistakes. It would, in fact, require a very great stretch of imagination to fancy what we know to be straight, and of the same breadth throughout, is not so: if we can fancy that, we can also fancy that the further end of a building is not so high as the nearer one, and that instead of being horizontal, the cornices slope downwards. So much for the fuss made about entasis, including that about the hypothetical curvature in the horizontal lines of the Parthenon, where curvature was administered, if administered at all, in an exceedingly homœopathic ratio. EPISTYLIUM.—The architrave or horizontal course resting immediately upon the columns. Hence we should denote as _Epistylar Arcuation_ that system in which columns support arches instead of horizontal architraves and entablatures. See p. 75.