Robert Adams (handgun designer)

Robert Adams (1 December 1809 – 13 September 1870) was a 19th-century British gunsmith who patented the first successful semi-double-action revolver in 1851. His revolvers were used during the Crimean War, the Indian Mutiny, the American Civil War, and the Anglo-Zulu War.

Source: Wikipedia — Robert Adams (handgun designer) (CC BY-SA 4.0)