The windmill installed at Chrisholm is a Model 602 produced by the Aeromotor Company of Chicago, Illinois, a model made between 1888 and 1933, and this example was manufactured sometime between 1916 and 1919. It was previously owned and maintained by Earl Alsdorf and family, then loaned to Chrisholm and erected at this location by the Butler County Antique Machinery Club in the early 2000's. After sustaining extensive damage in 2008 from a windstorm caused by the remnants of Hurricane Ike, it was purchased in 2011 by Friends of Chrisholm, rebuilt, and later donated to MetroParks. Today it can be used to pump water for the animals at the Chrisholm Historic Farmstead. Windmills have been used since the 14th century to make difficult or repetitive tasks easier, first milling grain into flour and later also pumping water or powering wood saws. Their use declined in the 19th century as steam power, the internal combustion engine, and electricity were introduced, though windmills such as the Aeromotor remained common in the early 20th century where rural electricity was unavailable. Modern wind turbines generate electricity without causing air pollution. In pumping water, the blades catch the wind and turn the rotor, whose wheel and hub assembly drive gears that convert rotary motion into an up-and-down motion. That motion moves a sucker rod, or pump rod, inside a well pipe, operating a cylinder with a sealed plunger so that each upstroke pulls water into the cylinder and, with a check valve preventing backflow on the downstroke, the next upstroke forces the water up the pipe.