1 The Birth of Science - MSRI

106 4. Scientific Technology
In the sakiyeh (which was then called simply — the machine
par excellence) the lifting is done by a tympanum or a bucket chain. The
tympanum or the wheel that carries the buckets is solidly attached to a
smaller coaxial wheel, which stays dry; this second wheel has cogs suitably
meshed with those of a third, horizontal, wheel, which is pushed page 146
around its axis by an animal. A sakiyeh is first documented in a second
century B.C. tomb fresco in Alexandria, where it is shown pushed by
two oxen. 92 The use of animal energy to lift water must have been very
widespread (as it still is today). 93
Another machine for lifting water introduced in Hellenistic times was
the water-screw or Archimedean screw (). This well known tool
is characterized by a miraculous simplicity. The water flow it delivers is
continuous; no vestige is left of the age-old use of buckets. The water is
lifted directly, inside a tilted tube, by a helicoidal surface that fits snugly
within the tube and rotates with it.
Both sakiyeh and water-screw appear as products of the new scientific
technology. Indeed, they rely on the two new elements of mechanical
technology mentioned earlier, the gear and the screw, and moreover
they are the fruit of “technological design”. Thus, the helicoidal surface
of the water-screw does not seem related either to earlier instruments
or to natural objects having similar functions; at the same time, it is a
natural object of investigation in the context of Hellenistic geometry. 94
This by itself would be enough to suggest that its origin is connected to
scientific thought. But in fact we need not make conjectures: the invention
of the water-screw is attributed to Archimedes by concurrent testimonia
of Diodorus Siculus 95 and Athenaeus. 96 Its timing is further confirmed
by the utter absence of material, documentary or pictorial evidence
for earlier use. 97 Yet the tendency to cast as legendary all that has
92
See [Oleson: GRWL], pp. 184–185 or [Oleson: WL], p. 270.
93
Philo of Byzantium, presenting an air-operated device of his invention for lifting water, declares
it to be much better than the methods based on animal traction. See Philo of Byzantium,
Pneumatica, v, 84 (ed. Prager).
94
We have already mentioned on page 87 Apollonius of Perga’s On the cylindrical helix, which,
though of a later date, is significant in this context.
95
Diodorus Siculus, reporting what is in all probability information from Agatharchides (second
century B.C.), discusses the use of the water-screw to irrigate the Nile delta and attributes its invention
to Archimedes (Bibliotheca historica, I, xxxiv, 2). Diodorus returns to the water-screw in V,
xxxvii, 3–4 (a passage thought to be based on Posidonius), mentioning its use in draining Spanish
mines, and promises to discuss “in detail” () all of Archimedes’ inventions in the books
devoted to his time (these books have been lost).
96
According to Moschio’s book on the Syracusia (as quoted in Athenaeus, Deipnosophistae, V,
208f), that ship’s bilge water “was pumped out by a single man with the water-screw, an invention
of Archimedes”.
97
See [Oleson: WL], pp. 242–251.
Revision: 1.14 Date: 2002/10/24 04:25:47