higher placed pipe. The valve would close, locking the water into the higher pipe, and then propelling it in a jet stream. Archimedes' screw The Greek writer Athenaeus of Naucratis described how King Hieron II commissioned Archimedes to design a huge ship, Syracusia, which could be used for luxury travel, carrying supplies, and as a naval warship. Syracusia is said to have been the largest ship built in classical antiquity. According to Athenaeus, she was capable of carrying 600 people and included garden decorations, a gymnasium and a temple dedicated to the goddess Aphrodite among her facilities. Since a ship of this size would leak a considerable amount of water through the hull, the Archimedes' screw was purportedly developed in order to remove the bilge water. Archimedes' machine was a device with a revolving screw-shaped blade inside a cylinder. It was turned by hand, and could also be used to transfer water from a body of water into irrigation canals. The Archimedes' screw is still in use today for pumping liquids and granulated solids such as coal and grain. The Archimedes' screw described in Roman times by Vitruvius may have been an improvement on a screw pump that was used to irrigate the Hanging Gardens of Babylon, but this is disputed due to a lack of actual evidence. References Pumps