Gatling gun
The city was also the wartime home of Richard Jordan Gatling, a physician and entrepreneur, who invented the Gatling gun. Tested in Indianapolis and patented in November 1862, the hand-cranked, rapid-fire gun was a predecessor to the modern machine gun. The U.S. Navy adopted the Gatling gun during the war, where it was used on federal gunboats, but the U.S. Army did not formally adopt it for use until 1866.