Tidal-powered
Saw Mill
Periwinkles Restaurant in Essex, Massachusetts, stands on a site previously occupied by a tidal-powered saw mill, and across Main Street was a grist mill. At that time the bridge was a wooden drawbridge, and next to it was a dam and lock, which powered the two mills. When the tide came in the water would be impounded by the dam. After the tide receded the impounded water would be allowed to rush back into the river, providing power for the mills.