"Rest your mill-turning hand... the nymphs [now carry out] the chores your hands performed."
Antipater of Thessalonica, epigrammatist
The earliest reference to watermills is found in the writings of Antipater of Thessalonica, describing their use for the grinding of grain in the first century B.C.E. These ancient Greek devices consisted of a millstone mounted on a vertical axis and rotated against a stationary stone bed by a horizontal paddle wheel spinning in a fast-flowing stream. This type of watermill has also been discovered throughout Ireland, Scandinavia, and China.
The Romans were the first to devise a more efficient and versatile machine with a horizontal axis, which may have been inspired by ancient Eastern waterwheels, originally used for lifting water. The medieval Islamic nations embraced the watermill from the seventh century, building mills in bridges and on the sides of moored ships, or channeling water from dams to supply them. They were used to make pulp for paper, saw-wood, grind cereal, and crush sugar cane and mineral ores.
The nineteenth century brought a surge in the need for industrial power in northern Europe and North America, and new cast-iron waterwheels fed the demand. These were eventually replaced by steam engines, fueled by coal brought on the canals.
In northern England, 1880, water was used for the first time to generate electricity through a new type of turbine initially conceived in 1826 by Benoit Fourneyron. More plants followed, and in the 1920s 40 percent of electricity in the United States came from hydropower. Other countries, including Norway and Brazil, now meet almost all their electricity needs by harnessing the energy of flowing water.
