Lord Rayleigh

John William Strutt was born on November 12, 1842, at Langford Grove near Maldon, Essex, England, the eldest son of John James Strutt, 2nd Baron Rayleigh.⁠[1][2][3][4]

His mother, Clara Elizabeth La Touche Vicars, was the eldest daughter of Captain Richard Vicars, R.E.; the Crimean War hero Hedley Shafto Johnstone Vicars was her brother.⁠[1][2]

His father was born about 1797 in Harley Street, London, and his mother about 1825 in Port Louis, Mauritius; his younger siblings were Clara (born about 1845), Richard (about 1848), Charles (about 1850) and Edward (about 1855). The family had mostly been landowners with interests in the countryside and little previous interest in science; Robert Boyle was a distant relation.⁠[3]

He was frail as a child and youth, and illness repeatedly interrupted his schooling. He went to Eton College at ten but was too ill to finish the first year, spending most of his time there in the school sanatorium; he then spent three years at a private school in Wimbledon, entered Harrow School in 1855 and left after less than a year.⁠[1][2][5][6]

From the autumn of 1857 he studied for four years with the Rev. George Townsend Warner at Torquay, who prepared him for university; it was a boarding school, and there he began to show signs of mathematical ability. His frail health kept him from an ordinary public-school education, and his early education was mainly at private schools. MacTutor’s biography judges that, apart from these first signs of mathematical ability, he showed little sign of being anything other than an average child of average ability.⁠[2][1][6][3][7][8]

His first attempt at a scholarship to Trinity College, University of CambridgeUniversity of CambridgeThe University of Cambridge is a university in Cambridge, England, United Kingdom. It gives 1209 as its founding date, is made up of Schools, Faculties, Departments and autonomous Colleges, and is a member of the Russell Group.Open the full entry, failed; in October 1861 he entered Trinity College as a fellow commoner to read mathematics.⁠[2][3][8][1]

He prepared for the Mathematical Tripos under E. J. Routh of Peterhouse, took a course in chemical analysis with G. D. Liveing and attended the lectures of Sir George Gabriel Stokes, then Lucasian professor of mathematics. Stokes’s lectures included experiments, his only exposure to experimental science as a student, although Stokes does not appear to have directly encouraged him towards a scientific career. MacTutor’s biography regards the grounding in mathematical techniques he received from Routh as an important factor in his later work.⁠[2][3][9]

In 1864, about four months before the Tripos, he was awarded the Sheepshanks exhibition in astronomy.⁠[2][7][3]

In January 1865 he came first in the Mathematical Tripos as Senior Wrangler, and that year he also won the first Smith’s Prize and took his BA; the American Institute of Physics’ record dates the Smith’s Prize to 1864.⁠[2][1][3][10]

In 1866 he was elected a fellow of Trinity College, a position he held until 1871, though he did no college teaching. He took his MA in 1868.⁠[1][7][10]

On January 12, 1866, he was elected a Fellow of the Royal Astronomical Society.⁠[7]

For someone who would succeed to a title as the third Baron Rayleigh, a scientific career was not really acceptable, and various members of his family felt that way, but he was determined to devote his life to science and not to let his social obligations stand in his way.⁠[3]

After graduating he went, instead of making the customary tour of Europe, to the United StatesUnited StatesThe United States is a federal country in North America made up of 50 states, the District of Columbia as the seat of government, and territories such as Puerto Rico and Guam; its capital is Washington, D.C. The Continental Congress adopted the Declaration of Independence on July 4, 1776. The 2020 census (April 1, 2020) counted a resident population of 331,449,281, and the 435 seats of the House of Representatives are apportioned among the states on the basis of the census.Open the full entry, which was then recovering from the Civil War. On his return in 1868 he bought scientific apparatus and began independent research at the family seat, Terling Place, and that year he presented results on galvanometers at the British Association meeting in Norwich, his first research results to be presented.⁠[3][9][6][2]

He preferred very simple apparatus and made much of it himself; he was determined not to be content with the life of a country gentleman, and members of his family and his friends considered him somewhat of a freak.⁠[9]

His first paper, published in 1869, used analogies to give a lucid account of aspects of James Clerk Maxwell’s electromagnetic theory, making it somewhat more comprehensible; it was inspired by Maxwell’s 1865 paper on electromagnetic theory. He was also studying Hermann von Helmholtz’s 1860 results on the acoustic resonator.⁠[6][3][5]

In 1871 he published a paper in the London, Edinburgh and Dublin Philosophical Magazine proposing that the blue colour of the sky results from the scattering of sunlight by small particles in the atmosphere, the intensity of the scattered light varying inversely as the fourth power of the wavelength, so that shorter wavelengths are scattered more strongly; he based it on the elastic-solid theory of light rather than on Maxwell’s electromagnetic theory. MacTutor’s biography calls this the first correct explanation of why the sky is blue; BritannicaEncyclopædia BritannicaEncyclopædia Britannica is a general English-language encyclopedia first published in Edinburgh, Scotland, in 1768; the name also refers to its publisher, Chicago-based Encyclopædia Britannica, Inc. (which presents itself as The Britannica Group). The print edition ended in 2012, and the company’s main businesses since then have been the online encyclopedia Britannica.com, digital education products for schools and libraries, and Merriam-Webster dictionaries.Open the full entry’s article calls it perhaps his most significant early work and describes the resulting Rayleigh scattering law as classic in the study of all kinds of wave propagation.⁠[11][6][9][2][3]

That year he also published a long paper on the theory of resonance, based on Helmholtz’s work on the sensations of tone, which it extended in important ways.⁠[2][9]

That year he married Evelyn Georgiana Mary Balfour (died 1934), resigning his Trinity fellowship to do so. She was the daughter of James Maitland Balfour of Whittingehame, East Lothian, and his wife Blanche, a daughter of the 2nd Marquis of Salisbury; her brother Arthur James Balfour, a friend from his undergraduate days at Cambridge, later became prime minister and Earl of Balfour.⁠[2][1][3][5]

The Nobel Prize biography dates his severe attack of rheumatic fever to 1872 and the Oxford Dictionary of National Biography to the year after his marriage; Britannica’s article places it shortly after his marriage in 1871 and states that for a time it threatened his life.⁠[1][2][6]

To recover, he and his wife spent the winter in Egypt, travelling on the Nile by houseboat, and on this journey he began to write The Theory of Sound. MacTutor’s biography dates the Nile voyage from late 1872 into early 1873 and his return to England to the spring of 1873; the Nobel Prize biography states that he spent the winter in Egypt and Greece, and the Royal Institution’s profile that he spent time in Greece and Egypt for medical reasons.⁠[6][3][1][5][9][2]

On his father’s death in June 1873 he succeeded as 3rd Baron Rayleigh and took up residence at the family seat, Terling Place, Witham, Essex; his estates amounted to 7,000 acres.⁠[2][1][3][9]

The same year he was elected a Fellow of the Royal Society.⁠[2][1][3][10]

He built a laboratory next to the manor house. The Linda Hall Library’s article states that he had a wing added with a fully equipped laboratory, the Royal Astronomical Society’s obituary that the laboratory was notably plain in its equipment, and MacTutor’s biography that it produced important results with inexpensive apparatus.⁠[6][11][7][3]

The 1870s were a time of economic problems for farming in England, so that his income was far less than it might have been, and the depression obliged him to spend much of his time managing the estate. He experimented with artificial fertilizers on his land and was among the first to use nitrate of soda.⁠[3][2][1]

From 1876 he left the entire management of his land to his younger brother, Edward Strutt.⁠[1][2]

MacTutor’s biography and the American Institute of Physics’ record give his presidency of the London Mathematical Society as 1876–1878, the Society’s own obituary as 1876–1877. His long and close connection with the Society dated from 1871, much of his early and most characteristic work on sound first appeared in its Proceedings, and at a time of financial stress he made a generous contribution to its funds.⁠[3][10][8]

The first volume of the two-volume The Theory of Sound appeared in 1877 and the second in 1878. The work examines vibrations and the resonance of elastic solids and gases, the second volume concentrating on the propagation of sound in material media. It was for many years the standard textbook and was kept up to date through revisions. Britannica’s article calls it “the foremost monument of acoustical literature,” the Dictionary of Scientific Biography “still a vade mecum in every acoustical research laboratory,” and the London Mathematical Society’s obituary “a classical achievement.”⁠[6][1][9][2][8]

The Oxford Dictionary of National Biography states that had James Clerk Maxwell refused the Cavendish chair of experimental physics in 1871, Rayleigh would have been its first holder. After Maxwell’s death in 1879, William Thomson (later Lord Kelvin), not wishing to leave Glasgow, declined the post; in response to a pressing invitation Rayleigh accepted it, not without some reluctance, in December 1879, becoming Cavendish Professor of Experimental Physics and head of the Cavendish Laboratory, the second holder of the chair. The Royal Astronomical Society’s obituary gives his Cambridge professorship as 1880–1884.⁠[2][9][1][6][8][7]

The University immediately offered him the chair, as he was universally agreed to be the only successor to Maxwell. His estate depended on its dairy herds, and the London chain of dairy shops and milk rounds of “Lord Rayleigh’s Dairies,” which cut out the middleman, was a well-known and profitable business, but its profits were falling in 1879. Dennis Moralee’s history of the Cavendish Laboratory suggests that but for the agricultural depression he might not have accepted the chair at all; MacTutor’s biography, the Oxford Dictionary of National Biography and the Dictionary of Scientific Biography likewise state that the depression, by reducing his estate income and making the salary welcome, played a part in his acceptance, though MacTutor’s biography stresses that he was not there just for the money.⁠[12][3][2][9]

Finding the laboratory badly under-equipped, he asked for a fund of £1,500: the Duke gave £500, Rayleigh himself £500, and the rest was soon raised. He enlarged the workshops and, with R. T. Glazebrook and W. N. Shaw, jointly appointed after Garnett left, set up an organised practical course in which set experiments were allotted to students in rotation, with a demonstrator to help, a system that Moralee credits with having completely revolutionised practical instruction. Glazebrook and Shaw’s Practical Physics, for which Rayleigh had done preparatory work, was for many years the standard textbook of practical physics. The division of the Natural Sciences Tripos into two parts allowed separate advanced and elementary classes.⁠[12]

In 1880 sixteen students attended his lectures, eighteen took Heat and fourteen Advanced Electricity; practical classes ran for two hours on three days a week, and the numbers soon grew, so that some demonstrations had to be repeated. Much of the heavy work of organising the enlarged laboratory fell to him. He developed laboratory courses in heat, electricity and magnetism, properties of matter, optics and acoustics, and under his supervision practical instruction in experimental physics at Cambridge grew from a class of five or six students to an advanced school of some seventy experimental physicists. He published fifty papers during his five years at the Cavendish. MacTutor’s biography quotes Heathcote’s judgment that the task of organising the laboratory as a centre of instruction and research fell to him and that he accomplished it “with outstanding success.”⁠[12][3][1]

His most important work at the Cavendish was the redetermination of the absolute values of electrical quantities. The British Association for the Advancement of Science had set up a committee on electrical units in 1863, and Maxwell had begun the task for the Association; as the apparatus of the earlier experiments by Maxwell and Chrystal was not accurate enough, Rayleigh had new apparatus built and, with Glazebrook and Shaw, redetermined the ohm, the ampere and the volt, completing the work in 1884. These experiments helped to establish the standards of resistance, current and electromotive force, and the results were published by the Royal Society in what Britannica’s article calls a classical series of papers. Much of the work was done at Terling, where his wife’s sister Eleanor Sidgwick (née Balfour), who also collaborated with him in his capillarity studies, was an important collaborator and the Cambridge instrument maker George Gordon was employed to help him.⁠[12][2][9][3][1][6]

In 1882 he received the Royal Medal of the Royal Society and was president of Section A at the British Association meeting in Southampton.⁠[3][10][9]

At Cambridge he advised J. J. ThomsonJ. J. ThomsonJ. J. Thomson (Sir Joseph John Thomson, 1856–1940) was a British physicist who became Cavendish Professor of Experimental Physics at the University of Cambridge in 1884, discovered the electron, which he called the corpuscle, through his cathode-ray experiments of 1897, and received the whole of the 1906 Nobel Prize in Physics for his theoretical and experimental investigations on the conduction of electricity by gases; he later discovered the isotopes of neon with F. W. Aston and was Master of Trinity College from 1918 until his death.Open the full entry, Arthur Schuster and Jagadis Chandra Bose. The Dictionary of Scientific Biography judges that, though “not a brilliant lecturer,” he was an effective instructor who put laboratory instruction in elementary physics on a firm basis, a revolutionary accomplishment in England; the Linda Hall Library’s article calls him only an average teacher.⁠[10][9][11]

In 1884 he was president of the British Association for the Advancement of Science, whose meeting that year was held in Montreal, the first outside the United Kingdom; it was his second trip to the North American continent. In his presidential address he explained his results on the reduction to an absolute standard of measurements of electromotive force, current, resistance and other quantities.⁠[2][9][3]

Not wishing to extend his tenure at Cambridge, he resigned the Cavendish chair at the end of 1884 and returned to research at Terling; nearly all his later research was done in his private laboratory at Terling Place, where his famous discoveries, including the noble gases, were made.⁠[2][1][3][6][11][12]

In 1885, a few months after leaving Cambridge, he succeeded Stokes as Secretary of the Royal Society, serving until 1896; the eleven-year administrative post left him considerable freedom for research. While Secretary he found in the Society’s archives, and publicized, J. J. Waterston’s neglected memoir of 1846, which had anticipated some important features of the kinetic theory of gases.⁠[2][1][6][3][9]

That year he published “On waves propagated along the plane surface of an elastic solid” in the Proceedings of the London Mathematical Society, introducing the waves now named Rayleigh waves and suggesting that such surface waves might play a part in earthquakes. In 1879 he had written a paper on travelling waves, a theory that has since developed into the theory of solitons. MacTutor’s biography quotes Ash and Paige (1985), who note that Rayleigh regarded the 1885 paper as a fairly minor mathematical development whose value lay mainly in seismology, and that the subject was later rediscovered in electronic signal processing and grew explosively over the following two decades.⁠[3]

From 1887 to 1905 he succeeded John Tyndall as Professor of Natural Philosophy at the Royal Institution in London, a post that required residence in London for only a short time each year. From 1896 he and James Dewar were directors of the Royal Institution’s Davy-Faraday Research Laboratory (DFRL), a post he held until 1919, and from 1905 to 1919 he was its Honorary Professor.⁠[1][9][5][13]

In 1887 he suggested a method of reproducing colours by photography that Gabriel Lippmann later adopted in principle. From that year he was interested in astronomical aberration and its bearing on the theory of a luminiferous ether, favouring Fresnel’s assumption of a stationary ether despite the presumably null result of Albert A. Michelson’s famous 1881 experiment.⁠[3][9]

His Nobel Lecture opens with the sentence “The subject of the densities of gases has engaged a large part of my attention for over 20 years.” In an address to the British Association in 1882 he had suggested that the densities of gases needed redetermination, partly out of interest in Prout’s law: Regnault’s value for the density of oxygen, 15.96 times that of hydrogen, was close to the whole number 16, and the difference seemed not to be outside the limits of experimental error. From 1882 to 1888, beginning in Cambridge, he made precision measurements of gas densities, testing Prout’s hypothesis that atomic weights are multiples of that of hydrogen.⁠[14][2][6]

In 1892 he found that nitrogen taken from the air was slightly denser than nitrogen prepared from compounds such as ammonia. At first the two kinds differed by about one part in a thousand, entirely beyond the experimental errors; when he used oxygen instead of air in the ammonia method, the nitrogen from ammonia came out about one two-hundredth, or about 0.5 percent, lighter than that from the air. His weighings were so accurate that any possible error could be only one-fiftieth of that difference. A sample kept for eight months showed no change in density. That year he published a note in Nature asking for explanations.⁠[14][2][9][11][15]

He ruled out contamination and the imperfect removal of oxygen as explanations, and by the beginning of 1894 he was convinced that the air contained an undiscovered constituent. Using a technique introduced by Henry Cavendish about a century earlier, he passed electric sparks through atmospheric nitrogen with added oxygen to oxidize it and collected the residue that would not oxidize; Sir William Ramsay proposed another method of isolation, absorbing the nitrogen with heated magnesium. The two worked at first independently and joined forces at the beginning of August 1894; Ramsay, who isolated the gas by chemical means, had begun his work after Rayleigh published the density discrepancy. The Linda Hall Library’s article states that it is not known whether Ramsay took up the problem with Rayleigh’s permission.⁠[2][11][9][10][14][6]

On August 13, 1894, he presented the first preliminary results at the British Association meeting in Oxford. Samples sent to William Crookes and Arthur Schuster for spectroscopic analysis gave further evidence of a new element. On December 6, 1894, James Dewar suggested to the Chemical Society that the substance was a triatomic form of nitrogen, and letters criticizing the two men’s work appeared in The Times. They withheld the details partly because they wanted the Smithsonian InstitutionSmithsonian InstitutionThe Smithsonian Institution is a museum, education and research institution created by the U.S. Congress in 1846 with the bequest of the English scientist James Smithson. Based in Washington, D.C., it runs museums such as the National Air and Space Museum and the National Museum of Natural History, as well as the National Zoo.Open the full entry’s Hodgkins prize for discoveries associated with the atmosphere, which they later received. The announcement was made on January 31, 1895, at a meeting of the Royal Society held at University College LondonUniversity College LondonUniversity College London (UCL) is a university in London, England, United Kingdom. Founded in 1826, it is a member of the Russell Group.Open the full entry, to which the councils of the Chemical and the Physical Society were invited, chaired by Lord Kelvin, who in his presidential address less than a week earlier had called the discovery the greatest scientific event of the year. About 800 people were present when Ramsay read the paper; at the end of the meeting Rayleigh remarked, “I am not without experience of experimental difficulties.” Their joint paper appeared in volume 186 of the Philosophical Transactions of the Royal Society.⁠[2][11]

The gas made up about one percent of the atmosphere by volume and had a density about one and a half times that of nitrogen; because it would not enter into chemical combination it was named argon, from the Greek word for inactive. Its ratio of specific heats was 1.67, the highest possible value, showing that almost all the energy of its molecules is energy of translation.⁠[14][15][6][3]

Sources date the discovery differently: the Nobel Prize facts page and the Royal Institution’s profile state that he and Ramsay discovered and isolated argon in 1894, and the Linda Hall Library’s article that their two quests succeeded almost simultaneously in August 1894, while Britannica’s article and MacTutor’s biography give 1895. The Royal Astronomical Society’s obituary states that Ramsay collaborated in the later stages of the work. Ramsay shared the priority of the discovery with him. During the three years of the argon research, 1892–1895, he also published some twelve other papers, on the interference and scattering of light, the telephone and the audibility of sound.⁠[4][5][11][6][3][7][9]

Argon was the first of the noble or inert gases to be found; because it would not fit into Mendeleev’s periodic table some colleagues were reluctant to accept it as a new element, until Ramsay’s discovery of helium a few months later showed that a new column was needed. In his Nobel Lecture he described how Ramsay first obtained helium from the mineral clevite and how Ramsay and Travers later found minute quantities of helium and further new gases in the original argon mixture; the presentation speech likewise links the discovery of argon to Ramsay’s subsequent discovery of helium and the other noble gases.⁠[11][14][15]

He later wrote the article on argon for the 10th edition (1902) of the Encyclopædia Britannica. The London Mathematical Society’s obituary calls his articles on light in the Encyclopaedia Britannica “by far the best textbook on the subject which has ever appeared.”⁠[6][1][8]

In the 1890s he became interested in the problem of the complete radiation law. In 1900 he put forward the law of black-body radiation later named the Rayleigh–Jeans law, after him and James Jeans, a few months before Max Planck’s famous paper. The formula worked well for long wavelengths but failed for short-wave (ultraviolet) radiation, a problem that became known as the ultraviolet catastrophe and that Planck explained that year by proposing that energy is quantized and not infinitely divisible.⁠[2][9][11]

In 1901 he tried to detect double refraction in a material medium produced by its motion through a supposedly stationary ether; the negative result added to the evidence that no physical phenomenon can distinguish between the motions of two inertial systems, so that none can be identified as absolutely at rest.⁠[9]

At the coronation of Edward VII in 1902 he received the Order of Merit, as one of its original members; on receiving it he said that the only merit of which he was conscious was that of “having pleased myself by my studies.” That year he also gave the Bakerian Lecture of the Royal Society.⁠[3][2][1][9][7][10]

He received the whole of the 1904 Nobel Prize in Physics “for his investigations of the densities of the most important gases and for his discovery of argon in connection with these studies.” At the time of the award his affiliation was the Royal Institution of Great Britain in London.⁠[4]

He had been nominated to the Nobel committee by Lord Kelvin, and in the same year he nominated Kelvin.⁠[2]

At the award ceremony on December 10, 1904, J. E. Cederblom, President of the Royal Swedish Academy of Sciences, gave the presentation speech, describing how Rayleigh and Ramsay had together carried out the long and difficult experiments that proved the gas to be present in the air and established its chief physical and chemical properties, and presenting the discovery of argon as one link in a long series of fundamental contributions to physical science. On December 12 he delivered his Nobel Lecture, “The Density of Gases in the Air and the Discovery of Argon.”⁠[15][16]

In the lecture he also described later work on gases: his test for free hydrogen in the air indicated only about one-seventh of the 2/10,000 announced by Gautier; at low pressures Boyle’s law was fully verified, even for oxygen, for which C. Baur had found anomalies near 0.7 mm pressure; and by the comparison of densities the atomic weight of nitrogen came out at 14.01, against the 14.05 found by Stas.⁠[14]

The same year Ramsay received the Nobel Prize in Chemistry for his work on argon and the other inert elements.⁠[6][9][2]

He gave the prize money, about $38,500, to the University of Cambridge for the Cavendish Laboratory and the University Library; MacTutor’s biography states that it paid for an extension to the Cavendish laboratories.⁠[9][2][3]

In 1905 he was elected President of the Royal Society, serving until 1908, and in the same year he became a Privy Counsellor.⁠[6][1][2][9][3]

In one of his presidential addresses to the Royal Society, speaking of processes on the sun and of Hale’s discovery of the Zeeman effect in sunspots, he remarked that “we may do well to cultivate a humbler frame of mind than that indulged in by some of our colleagues.”⁠[7]

In 1908 he became Chancellor of the University of Cambridge, an office he held until his death; Arthur James Balfour succeeded him in 1919.⁠[6][2][10][9][17]

He died at Terling Place, Essex, on June 30, 1919, after an illness of a few weeks; the Nobel Prize biography gives the place of death as Witham, Essex.⁠[6][2][3][9][7][1][4]

He was still working on scientific papers until five days before his death and left three completed papers unpublished; in the last fifteen years of his life he produced ninety papers, remaining professionally active to the end. The Dictionary of Scientific Biography notes that he outlived his closest rivals, Helmholtz, Gibbs, Kelvin and Poincaré, by a measurable span of years. His last pocket-book lists everyday “Difficulties”: why winds are high in winter, why damp cold is so disagreeable, sunstroke and heatstroke, snow blindness, and the ironing of clothes to make them flat.⁠[6][9][2]

His eldest son, Robert John Strutt, succeeded to the barony. Probate of his estate, valued at £172,972 16s. 11d., was granted on February 25, 1920.⁠[2]

On November 30, 1921, J. J. Thomson, then Master of Trinity College, Cambridge, unveiled his memorial in the Chapel of St Andrew in Westminster Abbey, a white marble tablet with a portrait relief by the sculptor Francis Derwent Wood.⁠[18]

The inscription as transcribed by Westminster Abbey reads “John William Strutt: O M: PC: 3rd Baron Rayleigh 1842-1919,” “Chancellor of the University of Cambridge 1906-1919,” “President of the Royal Society 1905-1908.” and “An unerring leader in the advancement of natural knowledge,” giving his chancellorship as 1906–1919. The Oxford Dictionary of National Biography also quotes the last line.⁠[18][2]

The Nobel Prize biography, the Oxford Dictionary of National Biography and Westminster Abbey’s page state that he and his wife had three sons; the Royal Astronomical Society’s obituary states that he had four sons, of whom two were living when it was written.⁠[1][2][18][7]

His eldest son, Robert John Strutt (1875–1947), later 4th Baron Rayleigh, also became a physicist, was professor of physics at the Imperial College of Science and Technology (now Imperial College LondonImperial College LondonImperial College London is a university in London, England, United Kingdom. Formed under a royal charter in 1907, it focuses on science, technology and medicine and is a member of the Russell Group.Open the full entry) in London and from 1945 was President of the Royal Institution. His biography of his father, Life of John William Strutt, Third Baron Rayleigh O.M., F.R.S., appeared in 1924, and an enlarged edition in 1968.⁠[10][1][2][18][9][13]

He was a devout and practising Christian and among the first members of the Synthetic Society, founded in 1896.⁠[2]

In politics he held strong Conservative and Unionist opinions and was connected with the political scene through his wife’s family; he seconded the address in the House of Lords in 1875, and as a member of the House of Lords he intervened in debate only on rare occasions.⁠[2][1][3]

In the early 1870s, stimulated by William Crookes’s investigations, he became interested in psychical research; he later recalled experiments in hypnotic suggestion he had taken part in at Cambridge in the 1860s, which convinced him that unwilling minds could be influenced by suggestion. In 1882 he, Eleanor Sidgwick and her husband Henry Sidgwick were all founding members of the Society for Psychical Research; he served on its council and as a vice-president in the 1880s and 1890s. He investigated Home and other mediums, finding the results mostly disappointing, though “some of the incidents [were] difficult to explain.” In 1919 he was the Society’s president, and his presidential address, one of his last public appearances, announced no definite conclusions.⁠[2][10][3]

The Nobel Prize biography credits him with a fine sense of literary style, every paper he wrote, even on the most abstruse subject, being a model of clearness and simplicity of diction. His recreations were travel, tennis, photography and music. From boyhood he was expert in the photographic processes in use before silver-gelatine plates, which give a very fine grain; he already had a strong interest in photography as a Cambridge student, enjoyed photography and its scientific uses more than any other experimental technique, and published work on photography.⁠[1][7][2][18]

The Dictionary of Scientific Biography describes him as dividing his time between laboratory work and theoretical study, often pursuing several projects at once; he read widely, often finding his problems in the literature, and had a gift for spotting weak points in other people’s results and building his own contributions on them.⁠[9]

MacTutor’s biography and the Dictionary of Scientific Biography both describe him as modest, and MacTutor’s biography also as generous. The Royal Astronomical Society’s obituary describes his life’s work as “almost unremitting labour” and notes that his private circumstances left him free for scientific pursuits. The London Mathematical Society’s obituary notes that he preferred the simplest devices in both experiment and mathematics, treating mathematics mainly as an aid to physical understanding, though there was always “enormous mathematical power in reserve,” and that he had an intense admiration for Stokes, whose obituary notice he wrote for the Royal Society.⁠[3][9][7][8]

The Oxford Dictionary of National Biography records an anecdote that Edward VII once greeted him at a social gathering with “Well, Lord Rayleigh, discovering something I suppose?”⁠[2]

His early research was mainly mathematical, on optics and vibrating systems, and later extended to sound, wave theory, colour vision, electrodynamics, electromagnetism, the scattering of light, the flow of liquids, hydrodynamics, gas density, viscosity, capillarity, elasticity and photography. His Scientific Papers were issued in six volumes during 1889–1920.⁠[1]

The Nobel Prize biography states that his collected works contain 446 papers and MacTutor’s biography that his publication list has 446 items; the Dictionary of Scientific Biography counts 430 scientific articles and one book.⁠[1][3][9]

His mathematical work included papers on Bessel functions, on the relation between Laplace and Bessel functions and on Legendre functions, and he wrote on unusual subjects: insects and the colour of flowers (1874), the irregular flight of a tennis ball (1877), the soaring of birds (1883), the sailing flight of the albatross (1889) and the problem of the whispering gallery (1910). At Terling he tried to make cheap diffraction gratings by photographic means, at first with poor results, and this led him to study the resolving power of optical instruments: he proved that the resolving power of a plane transparent grating equals the product of the order of the spectrum and the total number of lines, and does not depend on how close the lines are. The Dictionary of Scientific Biography judges that he seems to have been the first to publish formally a clear definition of the resolving power of an optical device. MacTutor’s biography quotes Rott, who notes that he made explicit use of hydrodynamic similarity in the theory of aerodynamic drag and in the treatment of Aeolian tones, ideas that had a great impact on the later development of similarity theory.⁠[3][2][9]

He anticipated the French physicist Charles Soret in the invention of the optical zone plate. In 1899, addressing the anomalously high attenuation of sound observed in air, he proposed a relaxation mechanism involving the exchange of energy between the translational and internal states of molecules, a suggestion that later led to the establishment of the field of molecular acoustics. He also wrote a paper on sound waves of finite amplitude that extended the work of Rankine and Hugoniot on shock waves, and after 1905 his important contributions to acoustics concerned the binaural effect in human hearing.⁠[9]

The Dictionary of Scientific Biography states that he contributed nothing to Albert EinsteinAlbert EinsteinAlbert Einstein (1879–1955) was a German-born physicist who formulated the special theory of relativity in 1905 and the general theory in 1915 and received the 1921 Nobel Prize in Physics for his discovery of the law of the photoelectric effect. From 1933 until his death he was a professor at the Institute for Advanced Study in Princeton, New Jersey, United States.Open the full entry’s theory of relativity as such, could never develop much enthusiasm for Max Planck’s quantum theory and its subsequent development, and found Niels Bohr’s atomic theory “too radical and revolutionary for his liking.” The Oxford Dictionary of National Biography states that his convictions lay with classical physics and that he never attacked the quantum hypothesis or the relativistic view, though he showed no enthusiasm for the new non-classical framework. William B. Ashworth, Jr., of the Linda Hall Library writes that he could not accept the 1887 result of Michelson and Edward Morley, which showed that the luminiferous ether could not be detected, nor Einstein’s special relativity or Bohr’s 1913 proposal that the energy levels of the hydrogen atom are quantized, and that he never accepted quantum theory.⁠[9][2][11]

He applied Hill’s highly original methods in the lunar theory to the optics of stratified media and developed approximate methods that gave practical solutions to problems intractable in rigorous form, an early example being his treatment of the Helmholtz resonator as a system of one degree of freedom. In optics he first used the elastic-aether theory, later judged it “too wide for the facts” and worked in terms of the electromagnetic theory, concluding that scattering by the air molecules themselves would account for the blue of the sky; he simplified the theory of gratings and elucidated a question about Huygens’ principle that had long perplexed serious students of the subject.⁠[8]

In hydrodynamics he explained why Scott Russell’s solitary wave must be one of elevation only (Boussinesq sharing the credit) and returned repeatedly to Stokes’s problem of deep-water waves, improving the approximations; the influence of capillarity on water waves had been considered by Kelvin in 1871, and Rayleigh’s paper on it appeared in volume 9 of the London Mathematical Society’s Proceedings. Reynolds had identified the group velocity of water waves with the rate of transmission of energy, and Rayleigh gave a general proof for any type of wave; building on Kirchhoff’s work he developed a theory of the resistance experienced by a plane lamina moving through a stream, and in connection with Reynolds’s critical velocity he studied flow between planes and in a pipe, showing that the motion is stable provided the velocity profile is free from inflexions.⁠[8]

His optical work bearing on astronomy included “The Diffraction of Object Glasses,” published in 1872 in volume 33 of the Monthly Notices of the Royal Astronomical Society, which proposed blocking out the centre rather than the edge of an object glass for solar observation and was the only paper he presented to that Society. He made very successful photographic contact copies of the early glass gratings of Nobert and Rutherfurd, some giving brighter spectra than the originals, but Rowland’s far superior speculum gratings did not lend themselves to photographic reproduction, so the method saw little practical use. In 1879 he defined resolving power as the ratio of the whole wavelength to the smallest difference that could just be detected and showed that the resolving power of prisms depends solely on the aggregate length of glass traversed at their thick ends, its value being the product of this thickness and the dispersive power. In 1873 he drew attention to the broadening of spectral lines by the Doppler effect of moving molecules and was the first to show quantitatively the limit this imposes on interference; Lippich had raised the idea earlier, and Fabry and Buisson later used it to determine the effective temperature of the great nebula in Orion. He also wrote on stellar scintillation and on the rationale of the grinding and polishing processes of the optician.⁠[7]

From 1892 to 1901 he was Lord Lieutenant of Essex. He was also a Justice of the Peace.⁠[1][1][10]

From 1896 he was scientific adviser to Trinity House: the Nobel Prize biography and the American Institute of Physics’ record give his tenure as lasting until 1919, the Oxford Dictionary of National Biography and the Royal Institution’s profile give 1896–1911, and the Dictionary of Scientific Biography gives fifteen years. Trinity House maintained the fog warnings and lighthouses around the English coast, and in this post he was involved in the design of foghorns; Michael Faraday had held the same role from 1836 to 1865.⁠[1][10][2][5][9]

He chaired the War Office’s Explosives Committee, presiding over this government committee for six years, and was chief gas examiner for the London gas supply.⁠[2][9][1]

He was vice-chairman of the Treasury committee that recommended forming a national laboratory and played a major role in founding the National Physical Laboratory; when it was set up at Teddington, Middlesex, in 1900 he became president of its first executive committee, over which he presided until shortly before his death. From 1909 he chaired the government’s advisory committee on aeronautics.⁠[2][9][3][5][6]

In 1899 he received the Copley Medal of the Royal Society. The Oxford Dictionary of National Biography states that from about 1895 he became deeply interested in physical optics, work that won him the Rumford Medal; the American Institute of Physics’ record dates the Rumford Medal to 1914.⁠[3][10][2][1]

The London Mathematical Society’s obituary and the text of MacTutor’s biography date his De Morgan Medal to 1890, the chronology of the American Institute of Physics’ record to 1894 (its institutions list gives 1890). He received the Matteucci Medal of the Italian Society of Sciences (Accademia nazionale delle scienze dette dei XL) in 1894, became a member of the Royal Swedish Academy of Sciences in 1897, received the Albert Medal of the Royal Society of Arts in 1905 and the Franklin Institute’s Elliott Cresson Medal in 1913.⁠[8][3][10][10]

The Oxford Dictionary of National Biography and the Dictionary of Scientific Biography state that he received thirteen honorary degrees and honours or memberships from more than fifty learned societies; MacTutor’s biography gives, besides the Nobel Prize, thirteen honorary degrees, five government awards and honorary membership of five learned societies around the world. The Nobel Prize biography mentions honorary degrees in science and law.⁠[2][9][3][1]

His obituary notice in the Proceedings of the Royal Society, volume 98A (1921), was written by Sir Arthur Schuster. His notebooks, calculations and original manuscripts were acquired by the United States Air Force Cambridge Research Laboratories in Bedford, MassachusettsMassachusettsMassachusetts (officially the Commonwealth of Massachusetts) is a state in the New England region of the northeastern United States; its capital and largest city is Boston. One of the original 13 states, it ratified the U.S. Constitution on February 6, 1788, the sixth state to do so. Its population in the 2020 census (April 1, 2020) was 7,029,917.Open the full entry, where they are housed as the Rayleigh Archives; the John Rylands University Library, the Niels Bohr Library & Archives, the Library of CongressLibrary of CongressThe Library of Congress is the library of the United States Congress. Founded in 1800 and housed on Capitol Hill in Washington, D.C., it answers reference requests from Congress, the public and other federal agencies.Open the full entry, the Royal Society and the Royal Institution also hold related archival material. Besides his son’s biography, R. Bruce Lindsay published Lord Rayleigh, the Man and His Works in 1970.⁠[9][8][10]

In the presentation speech Cederblom praised the argon work for “a delicacy and precision that is very rarely met with” in physical research and said that Rayleigh’s investigations “will ensure him a prominent position in its history for all time to come.”⁠[15]

Britannica’s article states that the discovery of argon is generally considered his greatest single contribution to science and calls him, in his later years, “the foremost leader in British physics.”⁠[6]

R. B. Lindsay, author of the Dictionary of Scientific Biography article, writes that he “may justly be considered the last great polymath of physical science,” while noting that, unlike Maxwell, Planck, Bohr and Einstein, he was not boldly imaginative.⁠[9]

H. L., author of the London Mathematical Society’s obituary, writes that in the massive solidity of his work and the serene breadth of his judgment he “stands nearest perhaps to Stokes,” that he maintained to the full the tradition of the great dynamical school, that his genius was “in the highest degree illuminating,” and that his was a mind of the kind “we like to think of as peculiarly British.”⁠[8]

Ashworth of the Linda Hall Library writes that many late Victorian scientists regarded him as the heir of Maxwell and the equal of Lord Kelvin at Glasgow and Helmholtz in Germany; he adds that had Rayleigh died in 1900, without a Nobel Prize, his reputation would still rank with those of Maxwell and Kelvin, and that had he been born some thirty years later he would probably have been at the forefront of the new physics.⁠[11]

Dennis Moralee’s history of the Cavendish Laboratory suggests that of the eight Cavendish professors so far he is perhaps the least known, and his tenure the most difficult to write about; it describes his work as completely classical and him as one of the greatest classical physicists.⁠[12]

University of Cambridge: Official website: https://www.cam.ac.uk/ (opens in a new window).⁠[19]

Royal Institution: Official website: https://www.rigb.org/ (opens in a new window).⁠[20]