Louis Gathmann was an engineer and inventor who held numerous patents in many different fields. Initially, Gathmann created equipment for screening and sifting wheat and flour and held a number of patents for these devices. In the 1880s, Gathmann built three astronomical observatories in the Chicago area and was working on a new type of telescope lens. His Chicago home also included a domed observatory tower. Gathmann received a patent in the 1890s based on his research in weather modification. Gathmann later became interested in ordnance development and in 1901 invented the Gathmann Gunn, an 18 inch gun to be mounted on ships that was designed to send large charges of high explosives at water level. The gun was tested at the Government Proving Ground at Sandy Hook but was rejected by the U.S. military. In 1916, Gathmann invented a new type of battleship armor based on the use of air chambers and shock absorbers. Gathmann also had an interest in aviation and proposed an idea for a type of helicopter that he called an "Aero Locomotive" in the early 1900s. It is unclear if a patent was ever sought or issued for this invention. In 1904, Gathmann earned a patent in Great Britain for a propeller for flying machines. Gathmann died in June 1917.