Before the advent of the grain elevator, grain was usually handled in bags rather than in bulk (large quantities of loose grain). Dart's Elevator was a major innovation. It was invented by Joseph Dart, a merchant, and Robert Dunbar, an engineer, in 1842 and 1843, 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.