US Patent No. 2,103, granted May 22, 1841 to David Philips of Georgetown, Mercer County, Pennsylvania, for a "Railroad Cotton-Gin." The specification describes a cotton gin mounted on a car that travels around a circular raised track about fifty feet in diameter, driven by horse or steam power. A belt from the car's drum wheel turns the saw cylinder. It also describes the covered building, with a roof used for drying cotton and trap doors for moving it. One page carries the perspective drawing, and two pages carry the text and claim.