1 The Birth of Science - MSRI

96 4. Scientific Technology
termining bullet trajectories. By contrast, at the time of the catapults, the
projectile was impelled by an elastic force, which could be investigated
and modified using the scientific methods of the time. Thus, although we
do not know why there was no interest in studying trajectories (and how
can we be sure there wasn’t?), it is clear from a reading of the Hellenistic
treatises on military technology that Archimedean mechanics had important
applications to artillery. 50
That science was relevant to the military technology actually used is
proved not only by the efficiency of scientifically designed weapons, but
by the mushrooming of texts on military technology. Clearly, the knowledge
gained by scientists could not be used by builders unless mediated
by specialized texts. Despite the obviously sensitive nature of such information,
we know of several treatises, dealing in particular with the construction
of artillery weapons (belopoeica) and that of siege machines (polyorcetica);
among the authors we know about are Philo of Byzantium, Biton
and Athenaeus. 51 By Philo we have three texts: Belopoeica, Paraskeuastica
(on defense works) and Polyorcetica. 52 The descriptions contained in all
these Hellenistic treatises, and in particular in Philo’s Belopoeica, are of
great interest because they shed light on the general level of mechanical
technology in the third century. Among the technological innovations they
describe are universal joints (also called Cardan joints because they were page 134
credited to the sixteenth-century Italian scientist Gerolamo Cardano), used
for aiming, and flat-mesh conveyor belts (used in loading repeating catapults),
which have been attributed to Leonardo da Vinci. 53
Authors of military technological works based on Hellenistic mechanics
include several engineers who were active at the Pergamum court: we
have the short book that Biton dedicated in the third century B.C. to Attalus
I. 54 In imperial times Heron, too, wrote works on military technology,
two of which have survived. 55
50
See, for example, Philo of Byzantium, Belopoeica, 59 = [Marsden: TT], p. 123. We will return
in Chapter 10 to the question of whether a science of dynamics in the modern sense existed in
Hellenistic times.
51
Also called Athenaeus the Mechanic, and not to be confused with the homonymous author of
the Deipnosophistae.
52
These texts made up the three books of a single, vast treatise on “mechanics”. The Belopoeica is
included in [Marsden: TT]; the other two works, which survived only in part, were edited by H.
Diels and E. Schramm ([Philo/Diels]).
53
The manufacture of conveyor belts was one of the main difficulties in modern attempts to reconstruct
ancient repeating catapults. In 1904 E. Schramm succeeded in creating efficient weapons
using bicycle chains (which were then a recent innovation). Leonardo’s chains, similar to those
described by Philo, are illustrated in the Madrid codex (I, folios 5 and 10).
54
Biton, Construction of war engines and catapults = [Marsden: TT], pp. 66–103.
55
The already cited Belopoeica and the Cheiroballistra (in [Marsden: TT]).
Revision: 1.14 Date: 2002/10/24 04:25:47