7In the theatres of the Greeks the design is not made on the same principles as those above mentioned. First, as to the general outline of the plan: whereas, in the Latin theatre, the points of four triangles touch the circumference, in the theatres of the Greeks the angles of three squares are substituted, and the side of that square which is nearest to the place of the scene, at the points where it touches the circumference of the circle, is the boundary of the proscenium. A line drawn parallel to this at the extremity of the circle, will give the front of the scene. Through the centre of the orchestra, opposite to the proscenium, another parallel line is drawn touching the circumference on the right and left, then one foot of the compasses being fixed on the right hand point, with a radius equal to the distance from the left point, describe a circle on the right hand side of the proscenium, and placing the foot of the compasses on the left hand point, with the distance of the right hand interval, describe another circle on the left side of the proscenium.
7In the theatres of the Greeks, these same rules of construction are not to be followed in all respects. First, in the circle at the bottom where the Roman has four triangles, the Greek has three squares with their angles touching the line of circumference. The square whose side is nearest to the “scaena,” and cuts off a segment of the circle, determines by this line the limits of the “proscaenium” (A, B). Parallel to this line and tangent to the outer circumference of the segment, a line is drawn which fixes the front of the “scaena” (C-D). Through the centre of the orchestra and parallel to the direction of the “proscaenium,” a line is laid off, and centres are marked where it cuts the circumference to the right and left (E, F) at the ends of the half-circle. Then, with the compasses fixed at the right, an arc is described from the horizontal distance at the left to the left hand side of the “proscaenium” (F, G); again with the centre at the left end, an arc is described from the horizontal distance at the right to the right hand side of the “proscaenium” (E, H).