1911 Encyclopædia Britannica/Rayleigh, John William Strutt, 3rd Baron

RAYLEIGH, JOHN WILLIAM STRUTT, 3rd baron (1842-), English physicist, was born in Essex on the 12th of November 1842, being the son of the 2nd baron. Going to Trinity College, Cambridge, he graduated as senior wrangler in 1865, and obtained the first Smith's prize of the year, the second being gained by Professor Alfred Marshall. He married in 1871 a sister of Mr A. J. Balfour, and succeeded to the title in 1873. From 1879 to 1884 he was Cavendish professor of experimental physics in the university of Cambridge, in succession to Clerk Maxwell; and in 1887 he accepted the post of professor of natural philosophy at the Royal Institution of Great Britain, which he resigned in 1905. His early mathematical and physical papers, written under the name of J. W. Strutt, made him known over Europe; and his powers rapidly matured until, at the death of Clerk Maxwell, he stood at the head of British physicists, Sir George Stokes and Lord Kelvin alone excepted. The special feature of his work is its extreme accuracy and definiteness; he combines the highest mathematical acumen with refinement of experimental skill, so that the idea of ranking him as higher in one department than another does not arise. His experimental investigations are carried out with plain and usually home-made apparatus, the accessories being crude and rough, but the essentials thoughtfully designed so as to compass in the simplest and most perfect manner the special end in view. A great part of his theoretical work consists in resurveying things supposed superficially to be already known, and elaborating their theory into precision and completeness. In this way he has gone over a great portion of the field of physics, and in many cases has either said the last word for the time being, or else started new and fruitful developments. Possessing an immense range of knowledge, he has filled up lacunae in nearly every part of physics, by experiment, by calculation, and by clear accurate thought. The following branches have especially felt his influence:—chemical physics, capillarity and viscosity, theory of gases, flow of liquids, photography, optics, colour vision, wave theory, electric and magnetic problems, electrical measurements, elasticity, sound and hydrodynamics. The numerous scientific memoirs in which his original work is set forth were collected under his own editorship in four large volumes, the last of which was published in 1903. His most extensive single work is a book on Sound, which, in the second edition, has become a treatise on vibrations in general. His familiarity with the methods of mathematical analysis and a certain refinement of taste in their application have resulted in great beauty of form. His papers are often difficult to read, but never diffuse or tedious; his mathematical treatment is never needlessly abstruse, for when his analysis is complicated it is only so because the subject-matter is complicated. Of discoveries superficially sensational there are few or none to record, and the weight of his work is for the most part to be appreciated only by professed physicists. One remarkable discovery, however, of general interest, was the outcome of a long series of delicate weighings and minute experimental care in the determination of the relative density of nitrogen gas—undertaken in order to determine the atomic weight of nitrogen—namely, the discovery of argon, the first of a series of new substances, chemically inert, which occur, some only in excessively minute quantities, as constituents of the earth's atmosphere. Lord Rayleigh had an interest in abnormal psychological investigations, and became a member and vicepresident of the Society for Psychical Research. He was one of the original members of the Order of Merit, instituted in connexion with the coronation of King Edward VII. In 1904 he was awarded a Nobel prize, and at the end of 1905 he became president of the Royal Society, of which he had been elected a fellow in 1873, and had acted as secretary from 1885 to 1896. He remained president till 1908, in which year he was chosen to succeed the 8th duke of Devonshire as chancellor of Cambridge University.