In the late 1870’s, inventive Andrew Oliver studied the drawings of Archimedes (287-212 B.C.E) and built wind-driven screw pumps based on the ancient designs. Wooden blades rotated in the wind, turning the screw shaft visible under the clear panel. The turning screw hoisted salt water up and into a waiting trough, where it was sent to the next salt pond for more evaporation and crystallization. A pond of salt water took five years to produce enough salt to harvest. The Archimedes screw pumps stood 14 feet high and could raise 2,000 gallons of water per minute.