Mills
Mills: Harvesting Water & Wind Power Water Mills The ancient Egyptians, Greeks and Romans knew that the force of current in a river could be turned into mechanical energy by the use of a water wheel. Egyptians used a wheel of paddles, set in a river, to pump water up from the river for irrigation. Between the 3rd and 1st centuries BCE, Hellenistic engineers discovered that water wheels could be used to pump water out of mine shafts. The Romans used water power for pumping, and occasionally for grinding grains into flour. By the 3rd century CE, they had developed turbines (water screws with angled blades, built into water-tunnels to force the current through them at faster speeds). However, the use of water power in the Roman Empire was surprisingly limited. The cost of building and maintaining water mills exceeded the cost of slave labor to accomplish the same tasks, and slaves were not restricted to locations with fast-moving water. Consequently, water power only came to t...