The Archimedes screw.

The "Screw of Archimedes" is a device to lift water from a vessel or irrigation canal to a higher place. It consist of a cylinder in which a helical screw rotates. The animation shows how the water rises inside the cylinder as the screw rotates.

Animation: © Chris Rorres, reproduced by permission.

Archimedes' screw has been in use in Egyptian agriculture ever since Archimedes invented it in Alexandria. The photo below shows an Egyptian peasant farmer using it to pump irrigation water into a canal.

Modern applications of Archimedes screws include the pumping of water from mine shafts and other mining applications. The photo below shows a number of modern Archimedes screws at a factory ready for delivery to the customer.

Photos: check the copyright status.

Medieval illustrations often show Archimedes screws in plans for the perpetuum mobile.