C.H. McCormick. Portrait of Cyrus Hall McCormick (1809-1884), American inventor of the reaping machine for harvesting grain, which revolutionised nineteenth-century agriculture. Continuing experiments begun by his father, McCormick produced his first working model in 1831 at the age of 22. He patented his invention in 1834, made his first sale in 1840 and moved to Chicago in 1847 to begin large-scale production. The six million harvesters he manufactured opened the prairie lands to intensive agriculture, a major factor in America's prosperity. The modern combine harvester was developed from the reaper.