Prior to the advent of the grain elevator, grain was usually handled in bags rather than in bulk (large quantities of loose grain). The elevator was invented by a merchant named Joseph Dart and an engineer named Robert Dunbar during 1842–43, in Buffalo, New York. Using the steam-powered flour mills of Oliver Evans as their model, they invented the marine leg, which scooped loose grain out of the hulls of ships and elevated it to the top of a marine tower.