Van-Wyck Lefferts Mill
The following is from http://www.huntingtonhistoricalsociety.org/tide_mill.htm
The Van-Wyck Lefferts Tide Mill, which harnessed the tides for power, was the height of technology when it was built , by the Van Wyck family in 1795. Water powered mills need falling water and Long Island has few streams. But, as explained on the tour, the many bays and coves, with 8 foot tides, were an unfailing source of power. High tide filled the mill pond through the tide gate, and then, at low tide the trapped water was let out to turn the water wheel. The Lefferts mill is unique in that of the scores of tide mills on Long Islands north shore, it is the only one left with its building intact, on its original dam and with its original massive wooden gears. It is a Long Island treasure.