It is generally believed that turbines evolved from water wheels, that they are much more efficient and subsequently replaced them as hydraulic power converters. A closer look at the statistics however reveals a slightly different picture. In the 1850’s, an estimated 25-30,000 water wheels were operated in England alone, McGuigan (1978). In Germany 33,500 water wheels with power outputs ranging from 0.75 to 75 kW were licensed as late as 1925, Müller (1939). The water wheels were almost exclusively employed as mechanical power sources driving grist-, powder-, and mineral mills as well as textile and other machinery, mostly in small businesses. With the advent of the electric motor as a cheap power source however in the 1940’s and 50’s the water wheels disappeared virtually completely.
