'Interior of the Well House, Carisbrooke Castle, Isle of Wight', c 1850s.
© Science Museum / Science & Society Picture Library
Lithograph. After the water supply to Carisbrooke Castle failed in 1136, a new well was dug, to a depth of over 160 feet. A well house was built, with a large treadmill to raise buckets of water from the bottom of the well. Originally the treadmill was operated by prisoners, but they were later repaced by donkeys, as seen in this illustration.