th; but if it
is to be oblong, add together its length and breadth and, having got the
total, let half of it be devoted to the height up to the coffered
ceiling.

2. Further, the inside walls should be girdled, at a point halfway up
their height, with coronae made of woodwork or of stucco. Without these,
the voice of men engaged in discussion there will be carried up to the
height above, and so be unintelligible to their listeners. But when the
walls are girdled with coronae, the voice from below, being detained
before rising and becoming lost in the air, will be intelligible to the
ear.

CHAPTER III

THE THEATRE: ITS SITE, FOUNDATIONS AND ACOUSTICS

1. After the forum has been arranged, next, for the purpose of seeing
plays or festivals of the immortal gods, a site as healthy as possible
should be selected for the theatre, in accordance with what has been
written in the first book, on the principles of healthfulness in the
sites of cities. For when plays are given, the spectators, with their
wives and children, sit through them spell-bound, and their bodies,
motionless from enjoyment, have the pores open, into which blowing winds
find their way. If these winds come from marshy districts or from other
unwholesome quarters, they will introduce noxious exhalations into the
system. Hence, such faults will be avoided if the site of the theatre is
somewhat carefully selected.

2. We must also beware that it has not a southern exposure. When the sun
shines full upon the rounded part of it, the air, being shut up in the
curved enclosure and unable to circulate, stays there and becomes
heated; and getting glowing hot it burns up, dries out, and impairs the
fluids of the human body. For these reasons, sites which are unwholesome
in such respects are to be avoided, and healthy sites selected.

3. The foundation walls will be an easier matter if they are on a
hillside; but if they have to be laid on a plain or in a marshy place,
solidity must be assured and substructures built in accordance with what
has been written in the third book, on the foundations of temples. Above
the foundation walls, the ascending rows of seats, from the
substructures up, should be built of stone and marble materials.

4. The curved cross-aisles should be constructed in proportionate
relation, it is thought, to the height of the theatre, but not higher
than the footway of the passage is broad. If they are loftier, they will
throw back th