The Nobel Prize in Physics 1927
Arthur H. Compton, C.T.R. Wilson
Charles Thomson Rees Wilson
Born: 14 February 1869, Glencorse, Scotland
Died: 15 November 1959, Carlops, Scotland
Affiliation at the time of the award: University of Cambridge, Cambridge, United Kingdom
Prize motivation: "for his method of making the paths of electrically charged particles visible by condensation of vapour"
Charles Thomson Rees Wilson was
born on the 14th of February, 1869, in the parish of Glencorse,
near Edinburgh. His father, John Wilson, was a farmer, and his
ancestors had been farmers in the South of Scotland for
generations. His mother was Annie Clerk Harper.
At the age of four he lost his father, and his mother moved with the family to Manchester, where he was at first educated at a private school, and later at Owen's College - now the University of Manchester. Here, intending to become a physician, Wilson took up mainly biology. Having been granted an entrance scholarship in 1888 he went on to Cambridge (Sidney Sussex College), where he took his degree in 1892. It was here that he became interested in the physical sciences, especially physics and chemistry. (It was also possible that Wilson's decision to abandon medicine was influenced by Balfour Stewart, who was professor of physics at Owen's College at that time - about a dozen years earlier, J. J. Thomson, who also went to Cambridge, had passed through the same College.)
When standing on the summit of Ben Nevis, the highest of the Scottish mountains, in the late summer of 1894, Wilson was struck by the beauty of coronas and "glories" (coloured rings surrounding shadows cast on mist and cloud), and he decided to imitate these natural phenomena in the laboratory (early 1895). His sharp observation and keen intellect, however, led him to suspect (after a few months' work at the Cavendish Laboratory) that the few drops reappearing again and again each time he expanded a volume of moist, dust-free air, might be the result of condensation on nuclei - possibly the ions causing the "residual" conductivity of the atmosphere-produced continuously. Wilson's hypothesis was supported after exposure (early 1896) of his primitive cloud chamber to the newly discovered (end of 1895) X-rays. The immense increase of the "rain-like" condensation fitted excellently with the observation made by Thomson and McClelland immediately after Röntgen's discovery, that air was made conductive by the passage of X-rays. When, during the summer of that year, it was firmly established by Thomson and Rutherford that the conductivity was indeed due to ionization of the gas, there was no longer any doubt that ions in gases could be detected and, photographically, recorded and thus studied at leisure. Wilson's appointment as Clerk Maxwell Student, at the end of that year, enabled him to devote all his time for the next three years to research, and for a year subsequent to this he was employed by the Meteorological Council in research on atmospheric electricity. The greater part of his work on the behaviour of ions as condensation nuclei was thus carried out in the years 1895-1900, whilst after this his other occupations - mainly tutorial - prevented him from dealing sufficiently with the development of the cloud chamber. Early in 1911, however, he was the first person to see and photograph the tracks of individual alpha- and beta-particles and electrons. (The latter were described by him as "little wisps and threads of clouds".) The event aroused great interest as the paths of the alpha-particles were just as W. H. Bragg had drawn them in a publication some years earlier. But it was not until 1923 that the cloud chamber was brought to perfection and led to his two, beautifully illustrated, classic papers on the tracks of electrons. Wilson's technique was promptly followed with startling success in all parts of the world - in Cambridge, by Blackett (who in 1948 received the Nobel Prize on account of his further development of the cloud chamber and his discoveries made therewith) and Kapitsa; in Paris, by Irène Curie and Auger; in Berlin, by Bothe, Meitner, and Philipp; in Leningrad, by Skobelzyn; in Tokio, by Kikuchi.
Some of the most important achievements using the Wilson chamber were: the demonstration of the existence of Compton recoil electrons, thus establishing beyond any doubt the reality of the Compton effect (Compton shared the Nobel Prize with Wilson in 1927); the discovery of the positron by Anderson (who was awarded the Nobel Prize for 1936 for this feat); the visual demonstration of the processes of "pair creation" and "annihilation" of electrons and positrons by Blackett and Occhialini; and that of the transmutation of atomic nuclei carried out by Cockcroft and Walton. Thus, Rutherford's remark that the cloud chamber was "the most original and wonderful instrument in scientific history" has been fully justified.
In 1900, Wilson was made Fellow of Sidney Sussex College, and University Lecturer and Demonstrator. From then until 1918 he was in charge of the advanced teaching of practical physics at the Cavendish Laboratory, and also gave lectures on light. As well as his experimental work at the Cavendish Laboratory, he also made observations (1900-1901) on atmospheric electricity (mainly in the surroundings of Peebles in Scotland). In 1913, he was appointed Observer in Meteorological Physics at the Solar Physics Observatory, and most of his research both on the tracks of ionizing particles and on thunderstorm electricity was carried out there. In 1918, he was appointed Reader in Electrical Meteorology, and in 1925, Jacksonian Professor of Natural Philosophy. He was elected a Fellow of the Royal Society in 1900, and this Society also honoured him with the Hughes Medal (1911), a Royal Medal (1922), and the Copley Medal (1935). The Cambridge Philosophical Society awarded him the Hopkins Prize (1920), and the Royal Society of Edinburgh the Gunning Prize (1921), while the Franklin Institute presented him the Howard Potts Medal (1925).
After his retirement Wilson moved to Edinburgh, and later, at the age of 80, to the village of Carlops, close to his birthplace at the farmhouse of Crosshouse, at Glencorse. Life after this, however, was not an empty one: C.T.R. as his friends and colleagues called him, maintained social contacts, making a weekly journey by bus to the city to lunch with them. Scientifically, too, he was active to the end, finishing his long-promised manuscript on the theory of thundercloud electricity (Proc. Roy. Soc. London, August (1956)).
Among the few who enjoyed his personal guidance may be mentioned:
Wormell (in the general field of atmospheric electricity), C. F. Powell (Nobel Prize winner 1950, for his development of the photographic method of studying nuclear processes and the discoveries made therewith on mesons), P. I. Dee and J. G. Wilson.
In 1908, Professor Wilson married Jessie Fraser, daughter of Rev. G. H. Dick of Glasgow; there were two sons and two daughters.
He died on the 15th of November, 1959, in the midst of his family.
From Nobel Lectures, Physics 1922-1941, Elsevier Publishing Company, Amsterdam, 1965
This autobiography/biography was written at the time of the award and first published in the book series Les Prix Nobel. It was later edited and republished in Nobel Lectures. To cite this document, always state the source as shown above.
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