Archimedean, << `ahr` kuh MEE dee uhn, >> screw, is a device for raising water. It consists of a screw or an arrangement of blades sealed to the inside of a cylinder. The lower end is placed in the water. The upper end has a crank that turns the cylinder. The threads of the screw or the blades slowly raise the water until it flows out the upper end. This device was used in the Nile Valley for draining and irrigating land and is still used for some tasks. Some scholars believe it was invented by the ancient Greek mathematician Archimedes.
