The Power behind the Engine: In Figure the water of a small but rapid mountain stream is made to rotate a large wheel, which in turn communicates its motion through belts to a distant sawmill or grinder. In more level regions huge dams are built which hold back the water and keep it at a higher level than the wheel; from the dam the water is conveyed in pipes (flumes) to the paddle wheel which it turns. Cogwheels or belts connect the paddle wheel with the factory machinery, so that motion of the paddle wheel insures the running of the machinery.
One of the most efficient forms of water wheels is that shown in Figure, and called the Pelton wheel. Water issues in a narrow jet similar to that of the ordinary garden hose and strikes with great force against the lower part of the wheel, thereby causing rotation of the wheel. Belts transfer this motion to the machinery of factory or mill.
FIG. - A mountain stream turns the wheels of the mill.