A three-page dictionary entry on cotton gins from Knight's New Mechanical Dictionary. It describes the four main kinds (roller, comb, saw, needle) and details the Macarthy double roller gin, the Dobson and Barlow knife-roller gin, the Brown Saw Gin, the Eclipse Hulling Gin, the Eagle, Clement, Gullett "Magnolia" and Scattergood needle gins. It gives operating speeds, output figures for various cotton types, and illustrations of three machines.