born in Glasgow. After working under Robert Bunsen, he returned to Glasgow before taking up professorships at Bristol (1880–87) and London (1887–1912). In the early 1890s he worked with Lord Rayleigh on the gases in air and in 1894 they discovered argon. In 1898, with Morris Travers (1872–1961), he discovered neon, krypton, and xenon. Six years later he discovered the last of the noble gases, radon. He was awarded the Nobel Prize for chemistry in 1904, the year in which Rayleigh received the physics prize.