The empty shell of a windmill at the Annaberg sugar plantation on St. John in the US Virgin Islands.
If there was a steady breeze, sugar cane was brought to the windmill. Revolving sails–which have long since disappeared from this windmill–turned a central shaft, rotating the rollers and crushing the sugar cane stalks. Juice ran down the rollers into the gutter and flowed downhill to the factory for processing. 300-500 gallons of juice could be produced in an hour.