John William Strutt, 3rd Baron Rayleigh (1842-1919), English physicist and Nobel Laureate. Strutt was born in Essex and attended Harrow School and Trinity College, Cambridge. His father died in 1873, and Strutt was created 3rd Baron Rayleigh. In 1894, with Ramsay, he isolated argon gas from air, an achievement for which he was awarded the 1904 Nobel Prize in Physics. Strutt discovered the phenomenon called Rayleigh scattering which accounts for the blue colour of the sky. A man of ecclectic studies, he also showed how seabirds travelled by dynamic soaring, proposed the Duplex Theory of human sound location and experimented with nitrogen gas made active by an electrical discharge. From 1905 to 1908 he served as President of the Royal Society. This oil painting by Mable Messer hangs at the Royal Institution in London.