GREEK PLAYS IN GENERAL, 225 at equal distances. Let any side, mh, of an included triangle be taken to represent the direction of the scena, and parallel to this draw the line ag through the centre of the circle. The line 7nh pro- duced to on one side and to n on the other so as to make it double the diameter, or four times the radius of the circle, gives the front of the scene ; and the line ag marks the limits of the pulpitum on the side of the orchestra. The five angles, which fall within the scene, indicate the positions of the five doors opening on the stage ; and the other seven angles define the directions of the steps leading to the seats of the spectators. From this it appears that the orchestra in a Roman theatre formed a semicircle, of which the furthest point was one radius from the front of the stage, and one radius and a half from the front of the scene ; the scene was four radii in length, and the stage half a radius in breadth. The Greek theatre was arranged according to the following scheme^. Taking a circle agg, inscribe in it three squares nkfc, mieh, Igdy, so that the angles touching the circumference maj be equidistant from one another. As before, let any side, nlc, of an included square be taken to represent the boundary of the prosce- nium on the side of the spectators ; then a tangent j?r, drawn paral- lel to this side, will represent the front of the scene. Let o be the centre of the circle, and q the centre of the orchestra thus defined ; through q draw ah parallel to nk ; and from a and h, with the radius of the original circle, draw the arcs st, uv, cutting the pro- n.T.G. Fig. B. ^ Vitruvius, V. 8. 15
