The historian Diodorus Siculus attributes the invention of this device to Archimedes "when he was in Egypt." The hydraulic screw was employed to irrigate land and to empty water out of tunnels and ship bilges. It is a spiral device inserted into a wooden cylinder duly covered with pitch to waterproof. Vitruvius describes one or more persons who, before the crank handle became known, took turns at the exhausting operation of turning the cylinder with their feet.