RAYLEIGH, relf, JOHN WILLIAM STRUTT, third Baron (1842—) . A distinguished physi cist. He was educated at Trinity College. Cam bridge, graduated in 1865. as senior wrangler in the mathematical tripos, and became a fellow of the college in 1860. He succeeded to the title of baron in 1S73. He was professor of experimental physics in the University of Cam bridge during 1870-84, and professor of nat ural philosophy in the Royal Institution of London since 1887. He has been a fellow of the Royal Society since 1873. vice-president of the British Association (section A) since 1882, member of numerous other scientific so cieties, including the United States National Academy of Sciences, and a correspondent of the Institute of France. Since 1S96 he has been the scientific adviser to Trinity House, the British Lighthouse Board. In 1894 he discovered, in con junction with Professor Ramsay, a new element, present in the atmosphere, which he has since prepared in quantity and has named argon. For
this discovery he received from Columbia College, on recommendation of the National Academy of Sciences, the Barnard medal 'for meritorius ser vice to science.' Lord Rayleigh ranks as one of the greatest living physicists. His experi mental work has been largely in the field of electrical standards and in physical optics; but he has carried on important researches in nearly every branch of physics, especially in acoustics, where his investigations are of the greatest value. His work is characterized by extreme care and accuracy, and the use of the most simple appara tus, often home-made. He is the author of many valuable papers in the Philosophical Magazine, Philosophical Transactions, the Theory of Sound (2 vols., and 1894), and has edited J. Clerk-Alaxwell's Heat. His collected papers have been published in four volumes (London, 1899 1903).