Graham's wind engine.
Over 200 models of inventions, including some for farm machinery, are shown in an exhibit at the Hagley Museum in Wilmington, Delaware, through April of 1980.
The models are representative of thousands that were submitted to the U.S. Patent Office before 1880. After that, models were not required. Drawings and specifications are shown with the 'Little Machines.'
A hot-air engine is one of the models shown. It was patented by Hiram Kolburn, of Waterloo, Iowa in 1865. John Ericcson's success with his 'Caloric' hot-air engine in the 1850s set off many others, differing in details.
Another model is that of a wind engine, from a fellow Iowan, Peter D. Graham, of Corunna. The pitch of the vanes and thus the speed of the propeller shaft can be adjusted at the base of the windmill tower.
William Holds worth, of Traverse City, Michigan, won a patent for a steam locomotive with driving wheels gripping a single rail. Antone Stauffacher, of Juda, Wisconsin, made a cultivator with a ratchet adjustment as the patented feature.
The models also include home appliances, mill and factory machines, and weaponry. There are three invented by women. The exhibit includes pictures and information about the patent office. The models are from the collection of E. Tunicliff Fox, which he donated to the museum.