1 The Birth of Science - MSRI

4.3 Military Technology 93
[The Rhodians] placed all their ballistae and catapults upon the wall.
When night had fallen, at about the second watch, they suddenly began
to strike the helepolis with an unremitting shower of the fire
missiles, and by using other missiles of all kinds, they shot down
any who rushed to the spot. . . . The night was moonless; and the
fire missiles shone bright as they hurtled violently through the air;
but the catapults and ballistae, since their missiles were invisible,
destroyed many who were not able to see the impending stroke. It
also happened that some of the iron plates of the helepolis were dislodged,
and where the place was laid bare the fire missiles rained
upon the exposed wood of the structure. Therefore Demetrius . . . finally
assembled by a trumpet signal the men who were assigned to
move the apparatus and by their efforts dragged the machine beyond
range. Then when day had dawned he ordered the camp followers
to collect the missiles that had been hurled by the Rhodians
. . . they counted more than eight hundred fire missiles and not less
than fifteen hundred catapult bolts. 34
Mobile siege towers along the lines of the helepolis later grew to have
up to twenty floors. 35 The machines designed at the time of the siege of
Rhodes included ones capable of grabbing and lifting enemy matériel,
just like the “Archimedean” machines used in Syracuse to lift the ships
93 years later. 36
War machines such as siege towers and ramrods already had a long history
by the time that concerns us: the Assyrians were experts in their construction,
and that know-how was inherited by the Persians, who transmitted
it to the Greek world. According to Diodorus Siculus, the oldest
type of “catapult” — essentially a modified bow operated with the whole
body — was built in 399 B.C. by Dionysius I of Syracuse, 37 but it may go
back even further. 38
In Hellenistic times military technology, and particularly artillery, went
through a phase of rapid progress, starting with the invention of the tor- page 131
sion catapult, a weapon that, unlike the bent-spring variety (which could
evolve purely empirically from the bow), was based on a new principle:
torsion elasticity. 39 The first exemplars, which cast bolts, seem to go back
34
Diodorus Siculus, Bibliotheca historica, XX, xcvi, 3 – xcvii, 2 (Geer translation).
35
Vitruvius, De architectura, X, xiii, 5.
36
For designing such a machine Callias got the post of public engineer in Rhodes (Vitruvius, De
architectura, X, xvi, 3).
37
Diodorus Siculus, Bibliotheca historica, XIV, xlii, 1–2; XIV, l, 4.
38
Compare [Marsden: HD], pp. 48–64; [Milner], pp. 209–210.
39
The main work on the history of Hellenistic artillery is [Marsden: HD]. The surviving Hellenistic
treatises on the subject are collected and translated in [Marsden: TT].
Revision: 1.14 Date: 2002/10/24 04:25:47