book reviews Gifted discoverer of the neutron

The Neutron and the Bomb: A already deeply engaged in the problems gen­ Nobel prize in 1935. By now the Cavendish Biography of Sir James Chadwick erated by the discovery of nuclear fission, and was leading the world in nuclear physics, with by Andrew Brown the first half of the book is concerned with his an almost exclusively experimental approach Oxford University Press: 1997. Pp. 366. rise to a dominant position in nuclear physics that had been established by Rutherford but £29.50, $55 from a very humble start. Little would be was very much to Chadwick's taste. Their known of his early life if he had not talked experiments were economical in conception freely in 1964 to Charles Weiner, who must and their papers were notable for clear exposi­ James Chadwick (1891-1974) was taciturn have charmed him into uncharacteristic gar­ tion and, as far as possible, avoidance ofmath­ and little given to those merry quips, out­ rulity, even to speaking of the boyhood home ematical arguments - merits for which the breaks of rage or peccadilloes that can enliven on which he was usually silent. A scholarship author of this book must have been thankful. a biography. The tale of so sterling a character, took him to the University of Manchester, Chadwick's researches can be described with­ even when told as well as in this book, may be a where he would have read mathematics but out technical complication and still give a fair little short on light moments, but any reader for the mistake of going to the physics lecturer picture ofwhat was achieved. interested in the evolution of physics from an for an interview and having his original inten­ Despite Chadwick's preference for work­ academic passion to a leading role on the tion subverted. Thus, in due course, he came ing alone with simple bench-top apparatus, world stage will find it a fascinating story and a under Ernest Rutherford's influence, which Ernest Lawrence's invention of the cyclotron, worthy tribute to a great scientist. lasted until the great man's death in 19 38. and the consequent birth in America of a new Chadwick was nearly 48 when war broke Chadwick graduated and started research style of nuclear physics with unprecedentedly out in 1939, at the height ofhis career and fully in Manchester. He won a scholarship from the massive and expensive equipment, persuaded engaged in the construction of a cyclotron at Royal Commission for the Exhibition of 1851, him that Britain must follow suit or fall the University of Liverpool, which was to be only to learn that the commissioners insisted behind. Rutherford would have none of it, the most ambitious European venture in he hold it elsewhere. So in 1913 he went to and his forthright rejection of Chadwick's nuclear physics. Britain was then the leader in Berlin for a year with Rutherford's old associ­ proposals made a break almost inevitable. the first steps towards a nuclear bomb to ate Hans Geiger; and in Germany he stayed, Chadwick went off to the chair at Liverpool counter the assumed parallel effort in Ger­ interned at Ruhleben as an enemy alien after and set about realizing his ambitions in a seri­ many. The later decision by the United States war broke out, until November 1918. Life was ously run-down department. In the four years to join the race, with far greater resources, hard, and his subsequent prolonged periods before the outbreak of war he had achieved provided much scope for jealousy on both of ill-health may have started there. But the much, and the cyclotron was just about work­ sides, arousing real fear that only US citizens prisoners were resourceful, and organized ing, but he had pressing calls on his time and would be allowed to take part. It was Chad­ educational courses and even small-scale never published any original work with it, wick's mission to avert narrow-minded deci­ researches with the help of friends among the leaving everything to his junior staff. sions that would have damaged both nations. German scientists. One of the group, a Wool­ In fact, his career in academic research It brought out in him a skill at diplomacy that wich cadet named Charles Ellis who had been was over. By the end of the war, when he few would have predicted, and in three years caught on holiday, learnt about physics from returned to Liverpool, he was exhausted and of unremitting toil tested, almost to the limit, Chadwick and on release went to Cambridge out oftouch with thefinickydetailsofuniver­ his none-too-robust frame. He travelled to as a student, eventually joining Chadwick as a sity life under straitened conditions. Perhaps Los Alamos, New Mexico, in the middle ofthe member of Rutherford's Cavendish Labora­ it was the hopes of rediscovering his lost war to work on the Manhattan Project. tory staff. Utopia that persuaded him to accept the mas­ General Leslie Groves, in overall charge of In 1918 Rutherford was still at Manchester tership ofGonville and Caius College in 1948; American nuclear bomb development, was a and Chadwick returned to him there, but but whatever the initial pleasures of a return very different sort of man - large, blunt and accompanied him in his move to Cambridge to Cambridge, they were transient. Disagree­ autocratic, and utterly confident in his own the following year. From then until 1935 he ments with the younger, and sometimes judgement: qualities indispensable for suc­ was Rutherford's right-hand man, calmly effi- intolerant, fellows became more than he cess in the huge project. He quickly appreci­ cient in the administrative tasks that only could bear, and at the end of 1958 he resigned. ated Chadwick's intellectual strength irritated the professor, and at the same In those ten years he had not renewed contact and personal integrity, as he time taking a lead in the nuclear with the Cavendish, and his departure from had also recognized J. Robert research that was the principal Cambridge was hardly noticed outside the Oppenheimer's high qualities, activity of the Cavendish as well college that had failed to appreciate his great both men with characters as seeing to the needs of the gifts or to match his old-fashioned standards foreign to his own. Chadwick ever-growing population of of civility. and Groves found they could research students. Andrew Brown is a radiation oncologist talk freely together, and their From the early 1920s, Ruther­ and presumably not a stranger to nuclear friendship helped to overcome ford had hoped to find evidence physics. He has made a few slips in matters of the American desire to go it for a close association of the detail which experts will correct without trou­ alone, which was by no means proton and electron which ble and which are without consequence in the irrational in view of the genuine would act as a neutral compo- argument. He has made good use of what fear that security would be nent of nuclear structure, and in seem to be all the available archives except for a jeopardized by European 1932 Chadwick made the actual few still classified as secret. There is already a involvement. discovery of the neutron substantial collection ofbiographies of mod­ It was, of course, no which won him the ern physicists, and this book is a fine addition accident that Chadwick to their number D was chosen to represent Chadwick: great scientist Sir Brian Pippard is at the Cavendish Laboratory, British interests. He was - and a diplomat. Madingley Road, Cambridge CB3 OHE, UK.

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