John William Strutt, 3rd Baron Rayleigh, was an eminent physicist. Among his many appointments and honours he was joint winner of the 1904 Nobel Prize for his discovery of Argon with William Ramsay. Rayleigh’s first major work was on James Clerk Maxwell's theory of electro-magnetism and in 1879 he succeeded Maxwell as Cavendish Professor at the University of Cambridge. Rayleigh was appointed as Professor at the Royal Institution (Ri) in 1887 and in 1896 became joint Director of the new Davy Faraday Research Laboratory with James Dewar. Although his association with the Ri continued until his death, Rayleigh spent much of his time at his country house, Terling Place, working in his private laboratory. It is this laboratory which is depicted in the painting.