1 The Birth of Science - MSRI

68 3. Other Hellenistic Scientific Theories
in pneumatics ( ), 78 and a more applied one, the Commentaries
(), 79 where a great many machines were described.
Strato of Lampsacus, too, probably made significant contributions to the page 103
birth of pneumatics, but these are harder to document.
Unfortunately no work of Strato or Ctesibius has survived. Apart from
some indirect references, 80 our knowledge of this ancient science is based
essentially on the Pneumatica of Philo of Byzantium, who continued Ctesibius’
investigations, and on the homonymous and much later work by
Heron (first century A.D.). The supposedly Philonian Pneumatica is represented
by an Arabic text in 65 chapters, describing as many devices, and
by several Latin manuscripts. 81 The latter match the first 21 chapters of the
Arabic text, albeit with notable omissions; it is reasonable to assume that
this material was written by Philo, though certainly our texts are very corrupt.
By contrast, the chapters we have only in Arabic are highly uneven
in terms of technical sophistication and of the purpose of the machines
described. Clearly they are in fact a compilation based on heterogeneous
sources; 82 while many of the devices described are essentially amusements
(as in the homonymous work by Heron), the last part of the work is devoted
to water-wheels and water-lifting machines — applications of great
economic importance which, as we shall see, had appeared already in the
early Hellenistic period. 83
The word pneuma () has had in Greek a wide range of meanings,
which changed significantly through the centuries and between cultural
environments. The early meanings were air, breath, breathing, spirit, etc.
In Stoic thinking, pneuma is also a continuous medium that underlies exchanges
between the various parts of organisms 83a and of the universe. 83b
But Heron, at the beginning of his Pneumatica, states that pneuma is just
78
This work is cited by Philo of Byzantium in Belopoeica, 77, 12 = [Marsden: TT], p. 152. The
word here can mean either “theorems” or, more likely, “demonstrations”, in the sense
of demonstrative experiments.
79
Compare Vitruvius, De architectura, X, vii, 4.
80
For Ctesibius we have particularly important testimonia in Vitruvius and Athenaeus, besides
those in the works by Philo and Heron about to be discussed.
81
See [Philo/Prager] for an English translation of the Arabic and Latin texts; Prager’s introduction
is probably the most interesting modern article on ancient pneumatics. The standard reference
on the subject is [Drachmann: KPH].
82
Prager attributes to Philo only chapters 37–39, besides the ones surviving in Latin as well
([Philo/Prager], p. 66).
83
See Section 4.6.
83a
In animals, according to several authors, the transmission of information from sensory organs
to the central unit and from there to the muscles is mediated by pneuma running through the
nerves ([SVF], II, 826, 834, 838, 841, 856, 860–866, 870, 873, 879, 897, 898).
83b
Pneuma — in this function overlapping with the aether of some authors — is the medium for
interactions between the various parts of the universe, thanks to its tension () and its characteristic
tensional motion ( ©); in particular it allows the transmission of light ([SVF], I,
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