††††During the Middle Ages another type of windmill appeared: the tower mill. It consisted of a stone tower with a conical roof into which was set the wind shaft carrying the sails. In this type of mill, the roof alone was turned to face the wind. Usually there was a fantail device that turned the sails towards the wind automatically.
The wind-pump, originally looking like a tower windmill, was first developed in Holland for drainage purposes. In the United States, a light type of wind-pump, with wooden or steel sails supported on a tall steel girder tower was introduced for use on farms. These wind-pumps had a tail vane to turn them into the wind. They were later introduced into Australia and Europe. Wind-pumps of this type are still used today to raise water from wells for domestic and farm use and to drain farmland. Another development of the windmill is the wind turbine which is used to generate electricity.
