t
covered a space from right to left of not less than one hundred feet.
One hundred men controlled it, though it had a weight of four thousand
talents, which is four hundred and eighty thousand pounds.

CHAPTER XVI

MEASURES OF DEFENCE

1. With regard to scorpiones, catapults, and ballistae, likewise with
regard to tortoises and towers, I have set forth, as seemed to me
especially appropriate, both by whom they were invented and in what
manner they should be constructed. But I have not considered it as
necessary to describe ladders, cranes, and other things, the principles
of which are simpler, for the soldiers usually construct these by
themselves, nor can these very machines be useful in all places nor in
the same way, since fortifications differ from each other, and so also
the bravery of nations. For siege works against bold and venturesome men
should be constructed on one plan, on another against cautious men, and
on still another against the cowardly.

2. And so, if any one pays attention to these directions, and by
selection adapts their various principles to a single structure, he will
not be in need of further aids, but will be able, without hesitation, to
design such machines as the circumstances or the situations demand. With
regard to works of defence, it is not necessary to write, since the
enemy do not construct their defences in conformity with our books, but
their contrivances are frequently foiled, on the spur of the moment, by
some shrewd, hastily conceived plan, without the aid of machines, as is
said to have been the experience of the Rhodians.

3. For Diognetus was a Rhodian architect, to whom, as an honour, was
granted out of the public treasury a fixed annual payment commensurate
with the dignity of his art. At this time an architect from Aradus,
Callias by name, coming to Rhodes, gave a public lecture, and showed a
model of a wall, over which he set a machine on a revolving crane with
which he seized an helepolis as it approached the fortifications, and
brought it inside the wall. The Rhodians, when they had seen this model,
filled with admiration, took from Diognetus the yearly grant and
transferred this honour to Callias.

4. Meanwhile, king Demetrius, who because of his stubborn courage was
called Poliorcetes, making war on Rhodes, brought with him a famous
Athenian architect named Epimachus. He constructed at enormous expense,
with the utmost care and exertion, an helepolis one