looking upon this ensample of their valour
and encouraged by the glory of it, might be ready to defend their
independence. So from that time on, many have put up statues of Persians
supporting entablatures and their ornaments, and thus from that motive
have greatly enriched the diversity of their works. There are other
stories of the same kind which architects ought to know.

7. As for philosophy, it makes an architect high-minded and not
self-assuming, but rather renders him courteous, just, and honest
without avariciousness. This is very important, for no work can be
rightly done without honesty and incorruptibility. Let him not be
grasping nor have his mind preoccupied with the idea of receiving
perquisites, but let him with dignity keep up his position by cherishing
a good reputation. These are among the precepts of philosophy.
Furthermore philosophy treats of physics (in Greek [Greek: physiologia])
where a more careful knowledge is required because the problems which
come under this head are numerous and of very different kinds; as, for
example, in the case of the conducting of water. For at points of intake
and at curves, and at places where it is raised to a level, currents of
air naturally form in one way or another; and nobody who has not learned
the fundamental principles of physics from philosophy will be able to
provide against the damage which they do. So the reader of Ctesibius or
Archimedes and the other writers of treatises of the same class will not
be able to appreciate them unless he has been trained in these subjects
by the philosophers.

8. Music, also, the architect ought to understand so that he may have
knowledge of the canonical and mathematical theory, and besides be able
to tune ballistae, catapultae, and scorpiones to the proper key. For to
the right and left in the beams are the holes in the frames through
which the strings of twisted sinew are stretched by means of windlasses
and bars, and these strings must not be clamped and made fast until they
give the same correct note to the ear of the skilled workman. For the
arms thrust through those stretched strings must, on being let go,
strike their blow together at the same moment; but if they are not in
unison, they will prevent the course of projectiles from being straight.

[Illustration: PERSIANS

(From the edition of Vitruvius by Fra Giocondo, Venice, 1511)]

9. In theatres, likewise, there are the bronze vessels (in Greek [Greek:
ech