harmony of the stars. Taking that one of
these triangles whose side is nearest to the scaena, let the front of
the scaena be determined by the line where that side cuts off a segment
of the circle (A-B), and draw, through the centre, a parallel line (C-D)
set off from that position, to separate the platform of the stage from
the space of the orchestra.

2. The platform has to be made deeper than that of the Greeks, because
all our artists perform on the stage, while the orchestra contains the
places reserved for the seats of senators. The height of this platform
must be not more than five feet, in order that those who sit in the
orchestra may be able to see the performances of all the actors. The
sections (cunei) for spectators in the theatre should be so divided,
that the angles of the triangles which run about the circumference of
the circle may give the direction for the flights of steps between the
sections, as far as up to the first curved cross-aisle. Above this, the
upper sections are to be laid out, midway between (the lower sections),
with alternating passage-ways.

3. The angles at the bottom, which give the directions for the flights
of steps, will be seven in number (C, E, F, G, H, I, D); the other five
angles will determine the arrangement of the scene: thus, the angle in
the middle ought to have the "royal door" (K) opposite to it; the angles
to the right and left (L, M) will designate the position of the doors
for guest chambers; and the two outermost angles (A, B) will point to
the passages in the wings. The steps for the spectators' places, where
the seats are arranged, should be not less than a foot and a palm in
height, nor more than a foot and six fingers; their depth should be
fixed at not more than two and a half feet, nor less than two feet.

[Illustration: THE ROMAN THEATRE ACCORDING TO VITRUVIUS]

4. The roof of the colonnade to be built at the top of the rows of
seats, should lie level with the top of the "scaena," for the reason
that the voice will then rise with equal power until it reaches the
highest rows of seats and the roof. If the roof is not so high, in
proportion as it is lower, it will check the voice at the point which
the sound first reaches.

5. Take one sixth of the diameter of the orchestra between the lowest
steps, and let the lower seats at the ends on both sides be cut away to
a height of that dimension so as to leave entrances (O, P). At the point
where this cutting aw