1 The Birth of Science - MSRI

4.9 Heron’s Role 113
the pre-Heronian texts that we possess, 125 is implicit in Archimedes’ postulate
and was the basis for the Hellenistic syphons built centuries before
Heron. 126 Other examples could be added. SL: make sure page range
in footnote is nontrivial
Heron’s personal contributions concern at best some of the applications
he describes, not the underlying technology. Thus we should inquire how
far back the technology goes. We list here a few relevant facts.
Heron’s use of mechanical technology and fluid technology is based on
mechanics, hydrostatics and pneumatics, scientific theories that all date
from the third century B.C. The same century witnessed the invention
of foundational pieces of technology such as precision screws, gears and
valves, and an extraordinary technological development attested, inter
alia, by the already discussed testimonia on shipbuilding and war engines.
The link between Heron and his sources has been carefully analyzed in
the case of the treatises on artillery by Marsden, 127 who concludes that “in
spite of his own [Heron’s] date, the technical content of his work belongs
in the third century B.C.” 128 Marsden cites as evidence, in particular, that
details of weapons described by Heron (following Ctesibius’ work) had
already been critiqued by Philo of Byzantium, 129 and that Heron starts his page 155
Belopoeica by stressing the importance of artillery in safeguarding cities: a
comment obviously lifted from sources that predated the establishment of
the Pax Romana.
The building of automata also goes back to the third century B.C., more
precisely to the first half. According to Vitruvius (who cites as his source
the Commentarii of Ctesibius), the clocks built by Ctesibius could activate
automata at preset times. 130 Callixenus, writing about a famous parade organized
by Ptolemy II Philadelphus, mentions a statue of Nysa that would
stand up by itself from a sitting position, pour libations of milk and sit
down again. 131 Heron, in his book on the automatic theater (see page 111),
mentions several times a work of Philo of Byzantium on the same subject,
criticizing details and boasting that he could improve on Philo in some
particulars, such as the number of simultaneous movements of each au-
125
This absence has led to statements such as “the first attempt to explain their action [i.e., of
syphons] was that of Hero” ([Forbes: HES], p. 669), when it’s clear that we can draw no such
conclusion e silentio.
126
See pages 104–104.
127
In [Marsden: HD]; see also [Marsden: TT], pp. 1–2.
128
[Marsden: HD], p. 3.
129
This fact was once thought to imply that Heron preceded Philo (see [Heath: HGM], vol. II,
p. 302, for example). The fallacy of this logic hinges, as it does in many analogous cases, on the
falsehood of a premise implicitly taken as obvious: that the interval between the two scientists was
one of technological progress and not regression.
130
Vitruvius, De architectura, IX, viii, 4–5.
131 Athenaeus, Deipnosophistae, V, 198f.
Revision: 1.14 Date: 2002/10/24 04:25:47