Drawing of a windmill, 1816.
© Science Museum / Science & Society Picture Library
One of a series of pen and ink drawings and diagrams of a windmill at Margate, Kent, belonging to a Mr Pilcher. This picture shows a section through the mill head or top-cap of windmill. The top cap revolves automatically, assisted by the fantail, ensuring that the main sails always face into the wind and make the best use of the available energy