reaper, early farm machine drawn by draft animals or tractor and used to harvest grain. Its historical predecessors were the sickle and the cradle scythe, which are still used in some parts of the world. The earliest known reaper using animal power was described by Pliny the Elder as used in Gaul. It was pushed by an ox and consisted of a box on two wheels with a comb projecting from the front of the box. The heads of the grain were torn off by the comb and fell into the box. Modern attempts to make reaping machines began in England, where the first patent was issued (1799). The first reaper to win general acceptance was made by American inventor Cyrus McCormick in 1831. The grain cut by this reaper fell on a platform, from which it was raked by a person walking beside the machine. A number of improved reapers were developed later. The combine, which threshes the grain as it is reaped, has virtually replaced the reaper, although a self-raking type is still in limited use. The mower, used for cutting hay, was developed from the reaper in the 19th cent.
See C. McCormick, The Century of the Reaper (1931, repr. 1971).