by Kostas Gavroglu
© Oxford University Press 2004 All rights reserved
Strutt, John William, third Baron Rayleigh (1842-1919), experimental and mathematical physicist, was born at Langford Grove, Maldon, Essex, on 12 November 1842, the eldest son of John James Strutt, second Baron Rayleigh (d. 1873), and his wife, Clara Elizabeth La Touche, eldest daughter of Captain Richard Vicars RE and sister of the Crimean War hero Hedley Shafto Johnstone Vicars.
Education and marriage
Strutt started his education at Eton at the age of ten, but ill health prevented him from completing even the first year, having spent most of his time in the school sanatorium. After three years at a private school at Wimbledon he went to Harrow School in 1855, but stayed for less than a year. In the autumn of 1857 he was put under the care of the Revd George Townsend Warner, who took pupils at Torquay--a place which proved more congenial for his health and where he stayed for four years. His first attempt to enter Trinity College, Cambridge, on a scholarship was unsuccessful. In October 1861 he entered the college as a fellow commoner. He started his preparation for the mathematical tripos under Dr E. J. Routh of Peterhouse. He took a course in chemical analysis with G. D. Liveing and attended the lectures of Sir George Gabriel Stokes, Lucasian professor of mathematics. Strutt had been very much interested in photography and four months before the tripos examination he had been awarded the Sheepshanks exhibition in astronomy. In January 1865 he became senior wrangler. Strutt impressed the examiners with the lucidity of his answers in the examination. In 1865 he received the first Smith's prize, and he was elected a fellow of Trinity College in the next year. Right after his graduation Strutt--unlike many graduates who chose to visit European universities--went to the United States. After his return he purchased his first equipment and started his experimental investigations at the family seat, Terling Place, Witham, Essex. This was the origin of a unique laboratory where Strutt for the rest of his life carried out ingenious experiments with very simple equipment.
In 1871 Strutt resigned his fellowship to marry Evelyn Georgiana Mary (d. 1934), the daughter of James Maitland Balfour of Whittingehame, East Lothian, and the sister of an undergraduate friend, Arthur James Balfour, later earl of Balfour and prime minister. The year after his marriage Strutt had a severe attack of rheumatic fever and following his doctors' recommendations he spent a winter in Egypt. Shortly after his return his father died, in June 1873, and he succeeded as third Baron Rayleigh at Terling Place. In the same year he was elected a fellow of the Royal Society. The prevailing economic depression in agriculture forced Strutt to devote a considerable part of his time to the management of his estate. He was especially interested in experimenting with artificial fertilizers, and was among the first to use nitrate of soda. After 1876 he left the entire management of the land to his younger brother, Edward Strutt.
Psychical research
Rayleigh's involvement with psychical research started in the early 1870s. William Crookes's investigations had stimulated him to develop an interest in such phenomena. His sister-in-law Eleanor Balfour, who collaborated with him in his capillarity studies and who later assisted him in his researches at the Cavendish, and her husband, Professor Henry Sidgwick, were actively engaged with the study of psychical phenomena. In 1882 they were all among the founding members of the Society for Psychical Research. Rayleigh was a council member and vice-president throughout the 1880s and 1890s, and, in fact, one of his last public appearances was to deliver the presidential address of the society in 1919. He declared that he had 'no definite conclusions to announce' (Strutt, 380) and that nothing had occurred to shake him from 'forty five years of hesitation' (Strutt, 391). Despite his long involvement with the society he never became a convinced follower. Religious considerations should be also taken into account in assessing Rayleigh's involvement in psychical research for so many years. He was a devout and practising Christian and on more than one occasion he had stressed that it was absurd to adopt definite claims of faith over science or vice versa. Rayleigh was also among the first members of the Synthetic Society, founded in 1896, whose members sought a 'new synthesis of religious positions and convictions' (Oppenheim, 127). He held strong Conservative and Unionist opinions. The prospect of a political career did not attract him. He seconded the address in the House of Lords in 1875, and on rare occasions intervened in debate.
Acoustics and optics, 1871-1879
Nearly three-quarters of Rayleigh's papers dealt with problems in acoustics and optics. His long paper on the theory of resonance published in 1871 was based on similar work on the sensations of tone done by Helmholtz, and the extensions Rayleigh suggested were the beginnings of his eventually becoming the leading authority on sound. In the same year Rayleigh proposed a solution of one of the most intriguing problems in optics: why the colour of the sky is blue. Rayleigh used the elastic solid theory of light and not Maxwell's recently introduced theory, and proved that the scattering of light by small particles was a function of the inverse fourth power of the wavelength of the incident light. His early work in optics was not confined to theoretical considerations alone. In the laboratory at Terling he attempted to manufacture diffraction gratings by photographic means. These experiments, whose practical results were initially quite poor, led to the study of the resolving power of gratings. One of the important results of these researches was the proof that the resolving power of a plane transparent grating is equal to the product of the order of the spectrum and the total number of lines in the grating. This work was continued with a series of fundamental researches on the optical properties of the spectroscope, an instrument that in the late 1870s was becoming increasingly important in the study of the solar spectrum as well as of the spectra of the chemical elements. In 1872, during his winter in Egypt, Strutt started his Theory of Sound (1877) which for many years was the standard textbook.
Cavendish professor, 1879-1884
Rayleigh was to have been the first Cavendish professor of experimental physics at Cambridge in 1871 if James Clerk Maxwell had refused the chair. When Maxwell died in 1879 Sir William Thomson (later Lord Kelvin), at that time professor of natural philosophy at the University of Glasgow, was proposed to be the person to succeed him. Thomson did not want to leave Glasgow and the post was offered to Rayleigh, who accepted in December. Though he preferred to continue his researches at Terling the strains from the continuing agricultural depression played their role in his accepting the post. Rayleigh lectured on such varied subjects as colour vision, scattering, sound, electricity, magnetization, and the density of gases. He systematized laboratory instruction in elementary physics and this, in the coming years, became the basis for physics education in many other institutions of higher education. Above all, Rayleigh's stay at Cambridge was marked by the intricate research programme he initiated with the help of his assistants Richard Glazebrook and William Napier Shaw. This was the redetermination of the absolute units of the ohm, the ampere, and the volt. The British Association for the Advancement of Science (BAAS) had set up a committee for the determination of electrical units in 1863 and work to this effect had already been performed by Maxwell. The accuracy of the measurements, however, was doubted, and Rayleigh developed much more precise equipment than Maxwell's and organized the work, which demanded remarkable patience and painstaking care for its completion. Eleanor Sidgwick was an important collaborator at Terling, where much of the work was done. The investigation was completed in 1884 and the results stood the test of time remarkably well. The undertaking of such work had been encouraged by similar endeavours in France and Germany, and recognized the needs of industry. It was during Rayleigh's presidency of the BAAS in 1884 that the association held its annual meeting for the first time outside the United Kingdom, in Montreal. Rayleigh did not wish to extend his tenure at Cambridge and he resigned at the end of 1884. Terling Place remained his scientific headquarters for the rest of his life. George Gordon, an instrument maker at Cambridge, was employed to help him there. Rayleigh stayed at Terling even during his relatively demanding commitments in London.
Natural philosopher, 1887-1905
As well as his involvement with the BAAS Rayleigh served as the professor of natural philosophy at the Royal Institution of Great Britain from 1887 to 1905 and as the secretary of the Royal Society from 1885 to 1896 after the resignation of G. G. Stokes. Neither post required continuous residence in London. At the Royal Institution he was called on to deliver a number of lectures on topics of his own research interests or on topics of a more general interest. During his tenure at the Royal Society he discovered and publicized the memoir in which J. J. Waterston in 1846 had anticipated some of the important features of the kinetic theory of gases.
During the 1880s and up to the mid-1890s Rayleigh published papers on optical and acoustical radiation, electromagnetism, general mechanical theorems, vibrations of elastic media, capillarity, thermodynamics, filtration of waves in periodic structures, interference and scattering of light, the telephone and its technical problems, and on the measurement of the minimum audible intensity of sound. Rayleigh, in his work on scattering by small objects, obtained approximations for isolated scatterers, periodic structures, gratings, rough surfaces, and random media. He contributed on more or less every class of scattering problems. He generalized the reciprocal idea introduced by Helmholtz which was eventually used for the calibration of transducers. He was also the first to work out the coupling of circuits.
Argon
Few discoveries have been as dramatic as the discovery of argon in the atmosphere by Lord Rayleigh and William Ramsay, professor of chemistry at University College, London. The discovery of argon involved a bitter public dispute concerning the legitimacy of a chemical element whose most important characteristic was its inertness, and which forced the chemists to reassess the very notion of a chemical element.
Rayleigh's measurements for the exact determination of the densities of gases had started in 1882 in Cambridge and were continued until 1888. It was a programme aimed to test Prout's hypothesis by finding the atomic weights of gases and observing the extent to which they were multiples of the atomic weight of hydrogen. By 1892 Rayleigh had found a curious discrepancy. In a letter to Nature he noted the difference in density between physical nitrogen--derived by absorbing oxygen, carbon dioxide, and moisture from atmospheric air--and chemical nitrogen--derived from ammonia. It had been found that physical nitrogen was heavier than chemical nitrogen by about a thousandth. Further improvements showed that chemical nitrogen was about 0.5 per cent lighter than physical nitrogen. The first alternative Rayleigh entertained was that atmospheric nitrogen was too heavy because of the imperfect removal of oxygen from the atmospheric air, or chemical nitrogen was too light because when it was removed from ammonia it was contaminated with gases which were lighter than nitrogen. Further experiments by Rayleigh excluded both possibilities, and by the beginning of 1894 Rayleigh was convinced that the atmosphere contained a new, and hitherto unknown, constituent.
To isolate this substance Rayleigh used sparking and the addition of oxygen to oxidize nitrogen. Ramsay proposed another method of isolation and made use of heated magnesium which absorbed the nitrogen. Rayleigh and Ramsay were working independently until they joined forces at the beginning of August 1894. Rayleigh presented the first preliminary results during the meeting of the BAAS at Oxford on 13 August 1894. They continued their exhaustive experiments and the tiny samples they sent to William Crookes and Arthur Schuster for spectroscopic analysis provided additional evidence which confirmed the new element.
On 6 December 1894 James Dewar, in a talk at the Chemical Society, claimed that the assumed new substance was a triatomic form of nitrogen. Letters were written to The Times criticizing Rayleigh's and Ramsay's work, especially their unwillingness to make public the details of their investigations. Rayleigh and Ramsay kept the details private until they were absolutely certain about the new element because they wished to receive (which they did) the Smithsonian Hodgkins prize for discoveries associated with the atmosphere. The final announcement was made at a meeting of the Royal Society at University College, London, on 31 January 1895, less than a week after Lord Kelvin in his presidential address to the Royal Society had referred to the discovery of the new constituent as the greatest scientific event of the year. Lord Kelvin chaired the meeting to which the councils of both the Chemical and the Physical Society were invited. There were 800 people present when Ramsay read the paper. Rayleigh's comment at the end was quite characteristic: 'I am not without experience of experimental difficulties, but certainly I have never encountered them in anything like so severe and aggravating a form as in this investigation' (Rucker, 337).
The discovery of argon brought the 1904 Nobel prize for physics to Rayleigh, and the prize for chemistry to William Ramsay. Rayleigh had been proposed to the Nobel committee by Lord Kelvin in the same year that Rayleigh had proposed Kelvin for the prize.
Late research and public service
In the 1890s Rayleigh became interested in the problem of the complete radiation law, which was closely related to the distribution of energy in the spectrum of black body radiation. Though aware of the problems that electromagnetic theory, thermodynamics, and statistical mechanics were facing at the end of the nineteenth century, his convictions lay with classical physics and on its ability eventually to deal with such deadlocks. Rayleigh never attacked the quantum hypothesis or the relativistic view, but neither did he ever express any enthusiasm or show any sign of adopting the newly emerging non-classical framework. Surely his derivation of what came later to be called the Rayleigh-Jeans radiation law (published in 1900, a few months before Planck's famous paper on the distribution law) provided ample ground for entertaining such hopes, since the statistical principle of equipartition of energy among resonators appeared to work so well for long wavelengths as to raise hopes that a future solution about the short wavelengths would come from the same core of ideas. About 1895 Rayleigh became deeply interested in physical optics, work which won him the Rumford medal.
From 1896 to 1911 Rayleigh was the chief scientific adviser to Trinity House, which maintained the fog warnings and lighthouses around the English coast, and he was involved in the design of foghorns. He was also the chairman of the explosives committee of the War Office, and chief gas examiner of the London gas supply. Through his brother-in-law Balfour, Rayleigh had considerable influence. This was decisive against fierce resistance when he was vice-chairman of the Treasury committee which reported in favour of the formation of the National Laboratory, and then was appointed president of its first executive committee in 1900. Rayleigh was one of the first members of the new Order of Merit when it was established in 1902. After receiving the Nobel prize in 1904 he donated its cash award to Cambridge University to improve the Cavendish Laboratory and the university library. From 1905 to 1908 he served as president of the Royal Society. He also became a privy councillor in 1905. From 1908 to 1919 he served as chancellor of Cambridge University. In 1909 he was appointed president of the special government advisory committee on aeronautics, an appointment which led to his devoting much time to problems of aviation. He was the recipient of thirteen honorary degrees and held honorary memberships in, or received special awards from, over fifty learned societies. Edward VII is said to have accosted him at a social gathering with: 'Well, Lord Rayleigh, discovering something I suppose?' (Fulford, 21).
Rayleigh died at Terling Place on 30 June 1919. 'An unerring leader in the advancement of natural knowledge' is the inscription on his memorial in Westminster Abbey. Of his three sons the eldest, Robert John Strutt, became a professor of physics at Imperial College, London, and succeeded to the barony.
The last notes Rayleigh jotted at the end of his pocket book are very characteristic of his lifelong interests with everyday problems: 'Difficulties: Why are winds high in winter?; Why is damp cold so disagreeable?; Sun stroke and heat stroke; Snow blindness; Ironing of clothes to make them flat'.
KOSTAS GAVROGLU
Sources
R. T. A. Glazebrook, History of the Cavendish Laboratory, 1871-1910 (1910)
J. N. Howard, 'John William Strutt, third Baron Rayleigh', Applied Optics, 3 (1964), 1091-1101
J. N. Howard, 'The optics papers of John W. Strutt, third Baron Rayleigh', Applied Optics, 3 (1964)
J. N. Howard, ed., The Rayleigh Archives dedication, United States Air Force Research Laboratories Special Reports, 63 (1967)
R. B. Lindsay, Men of physics: Lord Rayleigh: the man and his work (1970)
J. Oppenheim, The other world: spiritualism and psychical research in England, 1850-1914 (1985)
C. R. Strutt, The Strutt family of Terling, 1650-1873 (1939)
R. J. Strutt, Life of John William Strutt, third Baron Rayleigh, enl. edn (1968)
R. Fulford, 'The king', Edwardian England, 1901-1914, ed. S. Nowell-Smith (1964)
A. Rucker, Nature, 51 (1894-5), 337
DNB
DSB
Lord Rayleigh [J. W. Strutt], Scientific papers, 6 vols. [1964]
d. cert.
Archives
Air Force Research Laboratories, Cambridge, Massachusetts, corresp. and papers
JRL, notes on offprints
NRA, priv. coll., corresp. and papers
Royal Institution of Great Britain, London, notebook and letters | BL, letters to Macmillans, Add. MS 55220
CUL, letters to Lord Kelvin
CUL, letters to Sir George Stokes
CUL, letters to Sir Joseph Thomson
ICL, college archives, letters to Silvanus Thompson
King's AC Cam., letters to Oscar Browning
MHS Oxf., corresp. with Frederick Jervis Smith
NA Scot., corresp. with Arthur Balfour
Royal Institution of Great Britain, London, Dewar MSS
Trinity Cam., corresp. with Sir Joseph John Thomson
UCL, letters to Sir Oliver Lodge
UCL, letters to Sir William Ramsay
Likenesses
P. Burne-Jones, oils, 1888, Trinity Cam.
F. Hollyer, photograph, c.1888, V&A [see illus.]
H. von Herkomer, oils, 1911?, Examination School, Cambridge
G. Reid, oils, exh. RA 1911, RS
W. Rothenstein, crayon and pencil drawing, 1916, NPG
W. Stoneman, photograph, 1917, NPG
F. T. D. [F. T. Dalton], caricature, chromolithograph, NPG; repro. in VF (21 Dec 1899)
E. Glazebrook, photograph, NPG
photographs, repro. in Lord Rayleigh [J. W. Strutt], Collected papers (1964)
Wealth at death
£172,972 16s. 11d.: probate, 25 Feb 1920, CGPLA Eng. & Wales
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