John Deere (inventor)

John Deere's polished steel plow, 1837 The tough, sticky soil of the Illinois prairie clung to cast-iron plows, so breaking new ground meant constant stops to scrape the blade clean. In 1837 Deere, a blacksmith in Grand Detour, made the first commercially successful steel plow, with a polished share that let the soil slide off instead of building up. The numbers show how fast farmers took to it: 75 to 100 plows a year by 1841, and more than 10,000 sold by 1855. Each one opened prairie that had resisted the plow, which is why this entry sits beside the medieval heavy plow rather than duplicating it: one unlocked Europe's wet clays, the other the American grasslands.