Characters in Rutherford's life
James Chadwick
(1891-1974)
Having mistakenly enrolled to study physics at Manchester University, James Chadwick chose to pursue this path after attending Professor Rutherford's first lectures. He became one of the great names in nuclear physics, discovering the neutron in 1932 and winning the Nobel Prize for Physics in 1935.
James Chadwick in 1912
James Chadwick's working periods with Ernest Rutherford:
1909-1913 : Manchester
1919-1937 : Cambridge
James Chadwick was born into a very simple family: his father was a cotton spinner and his mother a domestic servant.
Intelligent, serious and hard-working, he managed to obtain scholarships that allowed him to pursue a full education, until he was able to enter university in 1908.
Highly gifted in mathematics, he wanted to continue his studies at Manchester's Victoria University. So he went for the entrance interviews, which were held in Whitworth Hall, the university's landmark building for graduations, state dinners and all sorts of other ceremonies.
For the occasion, the huge hall was divided in two. James Chadwick sat on a bench opposite a recruiter, who began to ask him questions. The young man answered as best he could, but soon realised from the content of the questions that the recruiter was, without any doubt, a physics teacher. He understood that the room was divided in two: maths on one side, physics on the other. And he had sat on the wrong side.
Too shy to point out his misunderstanding, he continued the interview to the end... and was admitted to begin studying physics.
Chadwick tells the rest better than anyone. I will therefore quote his own words, published by the Royal Society in 1972.
That year, Mark Oliphant, who had worked with Rutherford from 1927 to 1937 at the Cavendish Laboratory in Cambridge, wrote a 17-page article entitled Some Personal Recollections of Rutherford, the Man. The text includes a few lines in the hand of James Chadwick, who recalls the circumstances that led him to work with Rutherford:
« I entered the University of Manchester in October, 1908, when I was not quite 17. I had intended to read mathematics, in which I had shown some ability at school, but by some mischance, I found myself enrolled to Study Honours Physics. Rutherford, was of course, a man beyond contact with First Year. Fortunately, it so happened that one of the staff who should have lectured to us on Electricity and Magnetism in our second year, took up a post in London, and Rutherford deputized for about a month while a new lecturer was appointed. This was more than 60 years ago, but I still remember the enthralling and stimulating experience of listening to Rutherford. He left it to us to read the books and the formal presentation of Electricity and Magnetism, but he filled in the background. From the purely teaching point of View he was perhaps not remarkable; but it was the first time in my course that I realized what physics was about.
In our third year we were given the alternatives of (1) some elementary research, or (2) continuing a formal course on Electrical Engineering from its physical aspect. I chose (1) and was given a simple task by Rutherford himself. I was terrified of him I think that he began with rather a poor opinion of me. But, as I lost my awe of him, his opinion began to improve. »
Manchester university, staff and research students, 1912 - Source : Alexander Turnbull Library, Wellington, New Zealand
Rutherford's team in Manchester in 1913.
Chadwick is in the second row, third from the right.
In the same row, the first on the right end is Harry Moseley and the fifth is Ernest Marsden.
The young woman in the front row is Margaret White.
Hans Geiger does not appear on the photo, as he has already left for Berlin at this time
Source : Manchester University
In 1913, Chadwick won a scholarship to the 1851 exhibition, as did Rutherford in 1895. This scholarship enabled him to continue his studies abroad. The young man chose to join Hans Geiger in Berlin. The German researcher had been Rutherford's assistant in Manchester since 1907 and had played a central role in several of Rutherford's discoveries and inventions.
Unfortunately, in 1914, after the outbreak of war, James Chadwick was interned, like all British citizens present on German soil.
He spent the next four years in the Ruhleben camp. Fortunately, through Geiger, he was able to obtain some equipment and carry out some experiments.
After his release, James Chadwick was able to return to England. He recounts his gradual return to the life of a researcher in the document already mentioned above (Some Personal Recollections of Rutherford, the Man) :
" On my return to England in December 1918, I naturally visited Rutherford as soon as I had recovered sufficiently. I found him engaged upon the artificial disintegration o f nitrogen and other work. He told me about the nitrogen results and showed me the apparatus. He was full o f good spirits.
As I had nothing in view, and was not fit to take up a regular position, even if I had been able to find one, Rutherford offered me a temporary job as part-time demonstrator in the elementary laboratories. This helped me greatly, providing a little money, which I needed, and time to recover.
A few weeks after his election to the Cavendish Chair, in April 1919, Rutherford suggested that I should go to Cambridge with him, to help in the transfer in the research work on radio-activity, etc.. . .
I was offered the Wolleston Studentship in Physics by Gonville and Caius College, of £120 a year, and entered as a Research Student in October 1919. "
Annual photograph of Cavendish staff and research students, 1920
In 1923, Chadwick became Assistant Director of Research at the Cavendish Laboratory. In this role, he selected student researchers and reviewed their papers before publication.
At the same time, he continued his own research. He was exploring a path imagined by Rutherford when, in 1919, he announced the discovery of the proton, the first particle to be identified as a constituent of the atomic nucleus.
In 1932, Chadwick's work led him to the discovery of the second particle present in the nucleus, the neutron, the existence of which Rutherford had already assumed in 1919.
This result earned James Chadwick the Nobel Prize in Physics three years later, at the same time as Irène and Frédéric Joliot-Curie were awarded the Nobel Prize in Chemistry.
Participants at the 1932 Bunsen Conference in Munster (from left to right) :
Seated: James Chadwick, Hans Geiger, Ernest Rutherford, Stefan Meyer
Standing: George von Hevesy, Mme Geiger, Lise Meitner, Otto Hahn
Source : Wikipedia
James Chadwick, Irène Joliot-Curie, Frédéric Joliot at the Nobel ceremony in 1935
Source : "The Nobel Prize" official website
In October of the same year, James Chadwick took over as director of the physics laboratory at the University of Liverpool.
To be continued...
Sources :
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The Neutron and the Bomb: A Biography of Sir James Chadwick, Andrew Brown, 2019
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Some personal recollections of Rutherford, the man, Marcus Oliphant 1972
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Nobel prize winners in physics, 1901-1950, page 331, Niels H. de V. Heathcote, 1953
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James Chadwick: The Brit chief who worked on the nuclear bomb, Rumeana Jahangir, BBC News, 2023
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