Treadmills for punishment

Treadmills for punishment were introduced in 1818 by an English engineer named Sir William Cubitt, who was the son of a miller. Noting idle prisoners at Bury St Edmunds gaol, he proposed using their muscle power to both cure their idleness and produce useful work.

Cubitt's treadmills for punishment usually rotated around a horizontal axis, requiring the user to step upwards, like walking up an endless staircase. Those punished walked around the outside of the wheel holding a horizontal handrail for stability.

Punishment treadmills remained in use until the second half of the 19th century; they were typically twenty-foot long paddle wheels with twenty-four steps around a six-foot cylinder. Several prisoners stood side-by-side on a wheel, and had to work six or more hours a day, effectively climbing 5,000 to 14,000 vertical feet (1.5 to 4 km). While the purpose was mainly punitive, the most infamous mill at Brixton Prison was installed in 1821 and used to grind grain to supplement an existing windmill which Cubitt had previously installed nearby. It gained notoriety for the cruelty with which it was used, which then became a popular satirical metaphor for early-19th century prisons.

The machines could also be used to pump water or power ventilators in mines.