Background
Source: Wikipedia
William Greener (1806–1869) was an English inventor and gunmaker. He developed a self-expanding bullet in 1835, an electric lamp in 1846 (patent specification 11076 of that year) some 33 years before Thomas Edison's patent in 1879. William Greener also invented the percussion system for firing cannon, made improvements to the miner's safety lamp and won a prize for designing a mechanical device by which four gates at railway/road level crossings could be opened or closed simultaneously.
