Sir Hiram Maxim and Hiram Percy Maxim
Sir Hiram Maxim (shown) was an American-born British inventor with several patents to his name for inventions like a mousetrap, curling irons, and steam pumps. He's best known however for his contributions to the firearm industry. Maxim was the inventor of the Maxim Gun, the first portable, fully-automatic machine gun. He credited his idea to an 1882 trip to Vienna, where he met an American who advised him the best way to really get rich was to “invent something that will enable these Europeans to cut each others' throats with greater facility.”
Inspired by a childhood injury caused by gun recoil, Maxim fell on the idea of harnessing recoil energy to prepare a gun for its next shot. Versions of the Maxim Gun were a staple of British firearms and were used extensively in World War I. Ironically, Maxim's work with guns rendered him completely deaf in his later years.
Maxim's son, Hiram Percy Maxim, would follow in his father's footsteps and is credited with inventing and selling the first commercially-successful firearms silencer, the Maxim Silencer, in 1902. The younger Maxim was also an avid automobile enthusiast, reportedly having attempted to build his own internal combustion engine at one time. While he was never able to build a completely successful engine, Hiram Percy Maxim was able to leverage the techniques used to create his silencer to develop automobile mufflers.
(Image source: Public Domain)