The late-classical/Helenistic city of Priene on the Anatolian west coast of present day Turkey had a main drainage canal with an unusual masonry outlet structure that allowed self-cleaning of the drainage outlet. This outlet structure contained a doubly curvilinear, contracting rectangular cross-section flow passageway that allowed drainage water to flow through the perimeter wall of the city. Hydraulic analysis by Ortloff and Crouch (1998) showed that the internal shape of the structure causes the flow to create multiple circulatory mixing flows that agitated and entrained debris in the outflow stream, self-cleaning the outlet and preventing clogging. Once again we see that the Greeks possessed a high level of awareness about the hygienic conditions needed for health. Priene must have been well planned because of the placement of the underground water supply network supplied from a system of reservoirs. In addition there was an elaborate channel drainage system to convey stormwater and waste out of the city.
Archimedes (287-212 B. C.), who has been considered by many as the greatest mathematician during antiquity, was the founder of hydrostatics and introduced the principle of buoyancy. He lived in Syracusa, located on Sicily. The foundation of hydraulics after Archimedes led to the invention of several hydraulic devices with applications ranging from the lifting of water to musical instruments. Archimedes’s helix or water screw (see Fig. 1.11) is the first device characterized as a pump by modern standards. The invention of the water screw is linked to the study of the spiral, on which Archimedes wrote the treatise, On Spirals in 225 B. C. The water screw consists of a cylinder with a continuous screw that extends the length of the cylinder forming a spiral chamber. To operate the device the lower end is placed in the water and the screw is turned with the handle (Fig. 1.10a) raising the water to the higher elevation. The hydrostatic principles that Archimedes developed have proven to be the most enduring achievements of Greek mechanics.
The force pump, a water lifting device, was invented by Ctesibius of Alexandria (ca. 285-222 B. C.), who also invented other instruments like the water clock (clepsydra) and the hydraulis which is a water organ. Vitruvius, the Roman author of De Architectura, was the only ancient author to attribute the invention of the force pump to Ctesibius of Alexandria by calling the device - Ctesibica machina (x,7,1) and by
Fig. 1.11 Illustrations of the Archimedes Screw (a) Chambers Encyclopedia, J. B. Lippincott Company, Philadelphia, 1875
The comment in (x,7,4) nec tamen haec sola ratio Ctesibii fertur exquisita (and this is not the only choice device of Ctesibius current) (Oleson, 1984). The force pump is described in a later chapter on Romans in a section of Roman hydraulic devices. The principal of the siphon has been attributed to him. Further discussion of the force pump is given in Chapter 7.
World History
