Archimedes' screw a crank mechanism in his "Bellifortis" (1405). This mechanism quickly replaced the ancient practice of working the pipe by treading. The Archimedes screw consists of a screw (a helical surface surrounding a central cylindrical shaft) inside a hollow pipe. The screw is usually turned by windmill, manual labor, cattle, or by modern means, such as a motor. As the shaft turns the bottom end scoops up a volume of water. This water is then pushed up the tube by the rotating helicoid until it pours out from the top of the tube. The contact surface between the screw and the
Acorn Archimedes computers or IBM compatible PCs eclipsed the Archimedes in their multimedia capabilities, which led to an erosion of the Archimedes market share. The Tesco Computers for Schools scheme later changed partnership from Acorn to RM plc and many other computer-related suppliers, which also led to the decrease of the Archimedes' educational market share. Acorn Archimedes The Acorn Archimedes is a family of personal computers designed by Acorn Computers Ltd in Cambridge (England) and sold in the late-1980s to mid-1990s, Acorn's first general-purpose home computer based on its own ARM architecture. The first Archimedes was launched in 1987. ARM's RISC design,