.......   . Vannevar Bush .... ....... Chadwick, Groves, and his advisor Tolman

... Among the issues at hand in A-bomb research was "how much uranium would be needed to create an explosion of neutrons to be hurled into atomic nuclei in order to create a sustainable chain reaction of neutrons expelled from impacted nuclei which would then impact other nuclei, expelling other neutrons, etc.?" (Who more appropriate a man to tackle such questions than "Jimmy Neutron" himself?) Chadwick was disturbed about the lack of experimental data about this issue. The relevant research could be performed using his cyclotron; Chadwick was the only Allied scientist to be able to do so, as all other cyclotrons outside of the neutral U.S. would be in lands under Axis occupation by July 1940. All knowledgeable officials were concerned that the Allies would be naked if Heisenberg etc. could build a bomb for Hitler, but as Chadwick's initial assessments worked their way up the U.K.'s bureaucratic chain, one official wrote "that we may all sleep comfortably in our beds, but ... Chadwick ...may do some further work on the subject."   Actually, Chadwick was sticking to his habit of refraining from speculating absent solid experimental evidence, which brought some embarrassment in April 1940 when the Frisch-Peierls Memorandum made arguments which, Chadwick confessed, had occurred to him but had been too speculative for him to feel right about presenting to the authorities; these arguments showed the distinct possibility that the amount of U235 needed to bring on a chain reaction could be, not a ton as had been suspected, but perhaps a kilogram.   Chadwick's endorsement of this theory clinched the view within the uranium committee of the Aircraft Production Ministry, that the prospect of German physicists reaching similar one conclusions required that testing the Frisch-Peierls theory receive priority consideration by U.K. intellectual and governmental institutions.
.... All committee members felt that one person must be put in control of uranium researchers all across Britain, with Chadwick, dean of physics researchers in Britain since Rutherford's death in1937, the clear choice;  on 20 June 1940, days after Hitler took Paris, Chadwick received this nomination from Sir Goerge Thomson, the chairman of what was henceforth called the MAUD Committee.
.... Largely on the basis of Chadwick's work, Thomson, wrote the first draft of the committee report, which was assessed at a Committee meeting on 2 July 1941. Chadwick led those concerned that this draft did not have separate sections about civil vs. military applications of atomic energy;  many were concerned that the report must be clear as to just how important the military application would be, and the committee decided to have Chadwick rewrite the report, which he submitted on 16 July after working 20 hour days for two weeks, 2-16 July.
.... This draft was shortly brought to War Cabinet's Scientific Advisory Committee, before which Chadwick testified in mid-September; as put by the Official history, "Chadwick, known by his fellow scientists to be cautious in stretching forward to conclusions, was able to assure them that the evidence was overwhelming."
.... The Thomson draft of MAUD would reach American hands almost immediately, with marginal effect; the chairman of the U.S. uranium committee, regarding the report as being over his head, would stash this copy in his safe. The British found the lack of a U.S. response to such a crucial document puzzling, so one of Chadwick's subordinates, Oliphant, went to the U.S. in late August, where he learned of the "safe" whereabouts of the Report copy;  vociferous complaining to Chadwick's friend Lawrence finally brought FDR's science advisor, Vannevar Bush, into action.   Bush sent two members of the uranium committee to Britain to consult with Chadwick and his colleagues; their version of these encounters, as described in the Smyth Report (the post-war U.S. Govt. report on the Bomb project) is worth quoting at length:

... the principal importance of this visit and other interchanges during the summer of 1941 lay not in accurate scientific data but in the general scientific impressions. The British, particularly J. Chadwick, were convinced that a U-235 chain reaction could be achieved ... They feared that if the Germans got atomic bombs before the Allies did, the war might be over in a few weeks. The sense of urgency which Pegram and Urey brought back with them was of great importance;

.... (Historians, e.g. F. Szasz, chide the Smythe Report for understating the British contribution.) The British official history is equally emphatic:

"Chadwick ... told Pegram and Urey ... 'I wish I could tell you that the bomb is not going to work, but I am 90 percent certain that it will.'" "Chadwick assured them, as he had ... the Scientific Advisory Committee, that the evidence that a bomb could be made was overwhelming. This assertion, coming as it did from Chadwick, carried great weight with the Americans, as with the Scientific Advisory Committee."

.... Actually, even before his MAUD report had reached the U.S., the Americans had wanted him to travel to the U.S., once they had accepted his positive report, on Hans von Halban's heavy water experiments at Cambridge, enough to start such experiments themselves. As the British official history puts it, in Spring 1941, U.S. officials "urged that Chadwick, with his great prestige, should go to America. 'Send Chadwick' was the call from Washington - a call that was to be repeated to great effect in 1943". H.M. Government preferred to retain Chadwick to keep alive its own bomb program, a decision later regretted; by the time Chadwick arrived in the U.S, in 1943, America's need for his expertise and stature had become less desperate. At the time of MAUD, however, "British science had won admiration in the Washington of 1941," according to Bundy; "The technical difference between the Einstein letter and the Maud report is great ... but the difference between the witnesses of 1939 and 1941 may be even greater ... FDR had politely thanked Einstein ... what he had now was ... a clear proposal for action."
.... In early October, Bush, received the final (Chadwick) version of MAUD; days later, on 9 October, Bush "rolled the dice," by bringing MAUD to the attention of FDR, whose response was "concise yet sweeping," authorizing Bush to proceed in all ways short of spending large sums, and revealing that he intended to fund the Bomb Project by means which would not compromise Project secrecy. As the expenditure authorization was all but inevitable, this date is regarded by historians as the real birthdate of the Manhattan Project. (Pegram and Urey would not return from Britain until December, and FDR would give the final "go" on 19 January 1942)

.... A 1941 poem by Australian professor Geoffrey Sawer, paraphrasing Emma Lazarus' inscription on the pedestal of the Statue of Liberty, celebrated British and others' achievements as follows:

................... Give me your battle lore,
................... Send Oliphant with radar, Whittle's planes,
................... Forey with penicillin; send Niels Bohr,
................... Penney and Chadwick; all of Freedom's brains
................... Will scarce suffice to guard my golden door.

.... In the McCarthy era, all four physicists named in this poem were denied visas into the U.S.

............ Epitaphs, Evolution of his Reputation, and "Fame" in our time
.... In 1991, the centenary of Chadwick's birth, a Chair of Experimental Physics at the University of Liverpool became the James Chadwick Chair of Experimental Physics. This university also named its physics facilities "Chadwick Laboratories" in 1959, and has the Chadwick Building (for the Department of Computer Science, the Chadwick Lecture Theatre, and the Chadwick Coffee Bar).
.... In 1995, at the time when his Nobel set became available, it was astonishing to learn that there existed not a single (full-length) biography of such an important Laureate; no doubt his first biographer, Dr. Andrew Brown, (1997) was correct to attribute this phenomenon to the fact that "Chadwick never sought the limelight and was always exceedingly modest .…" By 1997, over a dozen books had been written about the "Trial of the Century," as the O.J. Simpson circus was regularly called by a host of fools in the U.S. mass media.
.... Alas, after Dr. Brown’s contribution, people have started to catch on to the Chadwick story, from a human-interest as well from the substantive standpoint of his historical significance; (which historians will surely continue to conclude dwarfs that of the “Trial of the Century”) for instance, see the substantial section “Chadwick’s interesting career” on the Paris web page “Getting ready to make a bomb.” Those who agree with the media echo-chamber’s mantra about the “Trial of the Century” may as well continue on their merry way; those who try to see life as more than a series of driftings from fad to fad could do worse than to study a man who was famous only in the original sense of the term, ie. One who deserved fame.

"A physicist, a scientistdiplomat, and a good, wise, and humane man" - Lorna Arnold, official historian of British Atomic Energy Authority

  Putting out fires from Nazi bombing of Liverpool, WWII                Geiger Counter

.... Few stories, esp. in the history of science, combine such high stakes with such dramatic appeal. In what were up to that point the Experiments of the Century, Chadwick would research this Bomb issue in spring 1941 using his cyclotron, while his city, Liverpool, and indeed his Physics Department, were being hammered by the Luftwaffe; in one week 3,000 became casualties and more than 70,000 became homeless. The cyclotron was in the basement, and managed to avoid being hit. Occasionally he would step outside after a German bomb raid to check the city with a Geiger Counter for radioactivity, in case Hitler had already learned how to weaponize uranium. Important though his work was, resources in a Britain under siege were so scarce that he had to fight with the Ministry bureaucracy to get enough funds to be able to afford fuel to travel to even a town near Liverpool, in order to confer with personnel producing weaponizable uranium. He and his wife would move from Upstairs to sleep Downstairs, for safety's sake; the raids were so frequent that the Chadwicks stopped going to the bomb shelter, lest they get to do nothing else but go back and forth. Such conditions would make those encountered by physicists at Los Alamos seem to be blissful by comparison. Every night, the windows, and the cardboard which replaced them, would be blown out. (Their twin daughters had been sent to safety in Nova Scotia in July 1940.) .
.... Of the other scientists involved in the U.K. Bomb project, the most experienced were not British citizens, so none could be given access to the big picture; thus Chadwick alone, in spring, 1941, became the first person with the burden of knowing, as he vividly recalled decades later, (in a passage often quoted in the literature about the Bomb, as moving a passage as any in the annals of science) that the human condition had reached a turning point:

"I remember the spring of 1941 to this day. I realized then that a nuclear bomb was not only possible - it was inevitable. Sooner or later these ideas could not be peculiar to us. Everybody would think about them before long, and some country would put them to action. And I had nobody to talk to. You see, the chief people in the laboratory were Frisch and Rotblat. However high my opinion of them was, they were not citizens of this country, and the others were quite young boys. And there was nobody to talk to about it. I had many sleepless nights. But I did realize how very, very serious it could be. And I had then to start taking sleeping pills. It was the only remedy, I've never stopped since then. It's 28 years, and I don't think I've missed a single night in all those 28 years."

.... His reputation in the U.S. for cautious judgement was such that, when, in October 1941, his "MAUD Report" on the Bomb's feasibility reached President Roosevelt, the report persuaded FDR to authorize the Manhattan Project even before Pearl Harbor was attacked; before FDR received this Report, Oppenheimer would later admit, the U.S. Bomb effort had floundered, despite Einstein's famous 1939 letter to FDR (see Special Section "Alerting FDR to Bomb's Feasibility," below). Suffice for now to say that the trust which Allied statesmen were putting in Chadwick and other physicists, to accurately assess the prospects of building a Bomb, was not matched by Hitler's (lack of) trust in his physicists, so that Churchill and FDR would authorize the unprecedentedly massive expenditures on and deployments toward such an undertaking, whereas Hitler would not.
.... After the U.S. economy geared up for war, the gap between U.S. and U.K. resources was such that the U.S. was the clear senior partner, particularly since, as Mc George Bundy puts it, "the British at the political level were slow in understanding the difficulties in their own program in the year that followed the great intellectual achievement of the MAUD Report." Thus the U.S. effort became dominant, and the Manhattan Project was launched and placed under the direction of U.S. General Leslie Groves. Chadwick was viewed by H.M. Secret Service to be the physicist most likely to be able to persuade Niels Bohr to flee Nazi-occupied Denmark, so a message from Chadwick was smuggled to Bohr, who was thus persuaded to escape to Britain in the fall of 1943, thereafter coming to the U.S. to work with Chadwick, who was first sent to the U.S. in September 1943 as head of the U.K. Mission of scientists contributing to the Bomb Project, and as technical advisor to the U.K. members of the Combined Policy Committee which directed the Project. (He would return to Britain to meet Bohr, just escaped from Denmark, in late September, and then return to the U.S. in November.) As the leading figure in the MAUD saga, sending Chadwick made sense, but he had zero experience in international diplomacy strictly-defined, much less preparation for dealing with such a formidable person as Groves in such a crucial context as the Manhattan Project, the largest international scientific undertaking ever. His challenge was all the greater because of the decline in Anglo-U.S. relations after Britain had spurned the 1941 post-MAUD U.S. proposal for a joint Bomb Project; he would prove to be almost totally responsible for a startling improvement in this situation.

 
FDR and Churchill in Quebec

 

 

 

 

 

 

 

 

 

Baker House, Los Alamos, cabin of the Chadwicks

.... Chadwick and wife set up residence in Los Alamos in January 1944, in a large log cabin, (one of the few with bathtubs) chosen for them by Groves; the daughters arrived from Canada in early summer. Generally, Chadwick spent most of his time in Washington, D.C., and other places where U.S. facilities and meetings were located, including in Chicago and New York. He had authority over all non-American physicists in the Project, (except Bohr) all of whom were desperately needed, because, as Groves put it, the small number of qualified experimental physicists in the U.S. meant that "we could not afford not to use everyone possible." It was Chadwick's job to persuade them to endure Groves' "dictatorial" rush to build a bomb at all costs, with none of the leaks of project secrets so feared by Groves; Chadwick's stature as a Nobel laureate was indispensable for this task. His expertise and apolitical bent won Groves' confidence, and Groves concluded that Chadwick's reports from Los Alamos would be more reliable than those presented by leftists like Oppenheimer; his loyalty not in question, Chadwick could persuade Groves to modify his tight-security policy somewhat, particularly as to Groves' desire to isolate physicists from engineers. Only Groves, his American scientific advisor, (not a Nobel laureate) and Chadwick would be privy to an overall perspective of the project, and thus of its various facilities across the U.S. Furthermore, as Groves later put it, "if Dr. Chadwick had been in charge of the British mission at that time [of Red spy Klaus Fuchs' joining the mission]...I am sure that no such deception [by Fuchs] would have been attempted." Such was Groves' trust in Chadwick that Sir James would thereafter be by far Groves' closest friend among the scientists; to Groves, Chadwick was "wholly straightforward and honest...a true gentleman." This confidence in Chadwick would result in his sway coming to pertain to, not just the foreigners, but almost the entire project; one student of the matter (in a review of Brown's biography of Chadwick) calls him "Groves' viceroy among the scientists." Chadwick's and Groves' friendship would be lifetime.
.... To his scientific expertise he had to add diplomatic finesse, as when he managed to persuade his own government and French physicists of the error of their disputing Groves' veto of these physicists' wish to visit their homeland after the Liberation; the big secret did not leak to Hitler, and Chadwick got to see "his neutron" in action in the successful bomb test at Los Alamos. As described by William Lawrence, New York Times ace reporter, "Never before in history had any man lived to see his own discovery materialize itself with such telling effect on the destiny of man ..." Churchill, in his 6 August 1945 statement issued just after Hiroshima was devastated, would assess U.S.- British collaboration as follows:
.
The smoothness with which the arrangements for cooperation which were made in 1943 have been carried into effect ... reflects great credit on all concerned - on the members of the Combined Policy Committee which we set up; on the enthusiasm with which our scientists and technicians gave of their best - particularly Sir James Chadwick who gave up his work at Liverpool to serve as technical advisor to the United Kingdom members of the Policy Committee and spared no effort ...

    U.S. writer Stephane Groeff's 1967 book Manhattan Project (sponsored by Reader's Digest) would assert that "the contribution of the British mission was inestimable."
.
..................................................... Post-WWII
.... Chadwick flew to Britain in November 1945 to be knighted by King George VI, then returned to the U.S., representing the U.K. at the U.N. as both science advisor, and alternate representative, to the Atomic Energy Commission until summer 1946, when he tired of nuclear diplomacy and returned to Liverpool, only to return to the U.N. for two months early in 1947, before leaving the U.S. for good (see section below on visa rejection). He would continue to be a driving influence upon Britain's move to build a nuclear arsenal, succeeding in persuading the U.S. to honor its wartime agreement with the U.K. to share weaponizable uranium. He was named chairman of the new Royal Society Advisory Committee on the Nuclear Research Centre in January 1952. In 1948, he returned to Cambridge as Master of Gonville and Caius College, but later wearied of the politics there, leaving in 1958; it was during his Mastership at that Crick (with Watson) discovered the DNA double helix. He was offered the post of Vice-Chancellor of Cambridge, but declined for health reasons. Until his retirement in 1962, he continued to earn his reputation for being indefatigable by being immersed in the politics and diplomacy of nuclear weapons, serving as chair of the Nuclear Physics Sub-Committee of the U.K. Atomic Energy Advisory Committee, and as a member of the U.K. Advisory Committee on Atomic Energy.
.... Chadwick preferred obscurity to glory, and refrained from public statements on the politics of the bomb; he held that such debates were for the public, not scientists, to dominate. However, after retiring, he did participate in interesting ways: in 1961 Pope John XXIII named him to join fifty-five others as a member of the Pontifical Academy of Science; this did not prevent Chadwick from joining 80 other Nobel Laureates' 1965 petition to the Vatican against the Pope's opposition to birth control.
.... Chadwick can be said to have been the first, and greatest, scientist-diplomat Before Chadwick, science and statecraft were almost completely separate realms; after Chadwick's mission to the U.S., scientists would regularly be attached to diplomatic delegations in all conferences (esp. summit meetings) of real international importance. That his role has been so obscured is clearly due to the fact that his personal style was so opposite to the styles of Einstein and Oppenheimer, who enjoying the limelight; Chadwick's reputation with his colleagues for integrity, modesty, shyness and stiffness, was paralleled by a distant attitude toward the media, an attitude which almost certainly helped endear him to Gen. Groves.

.................. Significance of the Discovery of the Neutron in 1932, not later
.... This discovery, while immediately seen to be important, has been particularly underrated from the standpoint of the significance of its timing, since subsequent history may have been quite different had the neutron been discovered even a year later than it was. The eventual invention of an A-bomb was inevitable, but its timing mattered greatly. Had the post-1932 breakthroughs in nuclear physics, such as the creation of the first chain reaction, been likewise delayed even a year, the A-bomb might have been ready for use, not in August 1945, but in August 1946, too late to have been used against Japan, which would probably have been conquered by then. As put by Kai Bird and Gar Alperovitz, in their assessment of physics' progress from 1905 (Einstein) through 1932 (Chadwick) to1938 (Fermi),
.
It is rarely acknowledged that had this line of development not been moving at this particular rate we would never have gotten to ...the 1941 MAUD Committee report, and then to the Manhattan Project - to the point ... where large sums of money ... could have produced an atomic bomb by August 1945.
.
.... The significance of this wartime first-use of the Bomb was described by Chadwick thusly: .
It is ... fortunate that this weapon was developed during the war, firstly, because its development in time of peace would have occurred more or less concurrently in different countries and competition would thereby have been inevitable, and secondly, because the sufferings and havoc of the present war have branded into our minds the merciless nature of war and have made us long for peace as never before.

.... Without the memory of the horror of Hiroshima to deter war between the Soviets and the West, such a war probably would almost certainly have occurred, one way or the other, possibly with atomic weapons; the still-secret nature of this super-weapon (each superpower hiding Bomb-possession from the other until deciding to surprise the other with a devastating strike) would have had profound impact upon the strategic situation, with potentially fateful results. In the likely event that the U.S. finished building a Bomb before the Soviets, the U.S., in the event of war with the Soviets, would have faced a decision over Bomb-use even more momentous than that which Truman actually faced over Bomb-use against Japan, since he may or may not have been as confident of the lack of a Soviet retaliatory capacity as he actually was of the lack of a Japanese retaliatory capacity. At least the Soviets would have been less likely to miscalculate, had they produced a Bomb before the U.S. had revealed possession of such a device, in that their atomic capacity came (and would have come) partly from U.S. secrets delivered by pro-Soviet scientists working in the Manhattan Project almost from its inception; Soviet knowledge that the U.S. had a retaliatory capacity would likely have deterred the Soviets from striking first. In any case, such a war would have made the world a very different place than it is now.

 

........................................ Alerting FDR to Bomb's Feasibility

....................................................................................................... Contents of dossier on

........................................ Sir James Chadwick and his 1935 Nobel Prize in Physics

......................................................................................... for his discovery of the neutron in 1932

......... Chadwick's Significance Summarized...
by Dr. Burton Feldman, author of The Nobel Prize: a History of Genius, Controversey, and Prestige ( Arcade, 2000), in a letter to J. Schramek, 10 June 2001

.... known in Britain as the Bomb's Creator; chief researcher in Britain's pioneering studies of nuclear energy (conducted under the trying circumstances of the WWII German bombing of his lab); author of the historic (1941) MAUD Report, which persuaded FDR to launch the Manhattan Project (contrary to the popular belief that FDR was persuaded by the famous 1939 Einstein letter; see Bundy, McGeorge, Danger and Survival, on the significance of the MAUD Report, and on "Chadwick's masterful conduct of the ensuing British effort").

important, since beta rays are those important things, electrons. It also showed the way to better spectroscopy of what was going on in the nucleus-and the nuclear age was coming up quick, after Chadwick discovered the neutron. He is also credited with first stating that the strong force existed. After that comes a lot of work which eventually led to today's quarks. (The best account is Pais, Inward Bound, 158, where he calls Chadwick's 1914 work a "turning point"in modern physics; and Pais, Subtle is the Lord, 326-7 on Chadwick.)
.... So Chadwick holds up very well against anyone's Prize except those everyone looks up to: Einstein, Bohr, Rutherford, and few of that sort....

.............. from Wang, Zuoue & Badash, Lawrence,
. "James Chadwick," in Dictionary of World Biography: the 20th Century, ed. by Frank MacGill (Fitzroy Dearborn, 1999)

    The discovery of the neutron was a turning point in the history of science…scientists' research programs changed and scientists' conception of nature changed; Chadwick, furthermore, was one of the early organizers of scientific activities at a time when it became a large-scale enterprise….He recognized early the change from "little science" to "Big science" and tried to direct this change for what he saw as the benefit to both science and society.

1935 Nobel Prize in Physics

Nobel Prize diploma interior

One of the Founders of Atomic Physics

for the

... was one of the 100 most important milestones of the 20th Century,
(which produced "more discovery than in the rest of history combined") , .             and which paved the way for invention of the Bomb,
. and so was one of the most important scientific achievements of all time.

..................................................................... 1891-1974
"like the neutron he discovered, Chadwick moved unnoticed - but with awesome power"
. . and lived an exemplary life.

Gen. Groves' " Viceroy among the Scientists" in the . A-bomb Project,
... (which is one of the . legendary stories of modern times) and thus making him

Discovery of the Neutron , " a turning  point in the history of   ..............     .science,"  which, according to Time Magazine *

*13 April 1998

Nobel Prize
medal reverse

other Chadwick
& Nobel objects

Awards of Outstanding International Importance

Nobel Prize

medal obverse

.... As for Chadwick's Nobel Prize: He really is one of the great figures of modern physics but not as well- known as he should be. Probably for several reasons. He's an experimenter, and the theorists still get all the glory (as I said in the book) -even more than someone like Rutherford. Chadwick was of course one of Rutherford's "boys", and this did not help Chadwick's renown. Rutherford sort of swallows up everyone around him through the force of his personality. It was certainly outgoing and booming and the like-- and Chadwick, by all accounts I've seen, was the complete opposite. He was extremely reserved, personally even a locked-up man. This has no bearing on how great a physicist he was, only how good copy he was for the media (no reflection on the Globe).
.... He certainly deserved the Prize after he discovered the neutron. But that was frosting on the cake. You may know all this, but if not: Before that, he made at least 2 brilliant experimental advances. In 1914 he proved that the beta -spectrum was "continuous."   Up to then they thought it wasn't a set of lines but a number of discrete or noncontinuous lines. It seems they were using photographic plates which blurred. Chadwick used detection counters instead. Quite

Nobel Prize diploma exterior

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Products (site contents)

Winner of the

The first great Scientist-Diplomat; leader in the transition from "little science" to "Big science"

Awards of Outstanding International Importance to Statesmen and Heroines

.... Chadwick's aloof, professorial, but unpretentious and humane manner gained him the respect, . and generally the affection, of those working under him, thus helping him become

" ... the great physicist had proved himself to be a great diplomat and statesman, carrying many burdens ... each of these burdens would have seemed a full-time load. In this his main asset, besides his great energy, was the confidence in his integrity and good sense which he inspired in all who came into contact with him."
........................................... -- Sir Rudolf Peierls, co-author of the crucial Frisch-Peierls Memorandum,
............................................. and Chadwick's deputy (as supervisor of British physicists at Los Alamos)

.Chadwick studio
  portrait

Diploma translation & historical comments

"... Chadwick holds up very well against anyone's Prize except those everyone looks up to: Einstein, Bohr, Rutherford, and few of that sort...." -- Dr. Burton Feldman, author of the comprehensive critical history, The Nobel Prize: a History of Genius, Controversey, and Prestige

Sir James Chadwick

"He put his duty, whether to his country, university, or college, before everything." - wife Aileen

.... Chadwick (1891-1974) was born in Bollington, 18 miles from Manchester, England; son of a cotton spinner, and thus raised on meager means. Being the best science and math student in town, he won scholarships to the University of Manchester. He intended to study math, but entered physics line by mistake in 1908, and ended up with a Master of Science, 1912. Thereupon he received a Research Student Fellowship, which led him to Berlin. There he worked with Geiger, whose famous Geiger counter Chadwick employed, within a few months of arriving, for his first important contribution to physics, one concerning the beta radiation spectrum. This discovery resulted in his most significant encounter with Einstein, in 1914, at the Reichsanstalt near Berlin.
..... Chadwick had been working in Hans Geiger's laboratory to determine the status of beta-particle emissions. Before Chadwick had turned twenty-three years old, he would publish a paper on how he was able to determine that there was a continuous beta spectrum (but "up to a certain limit") rather than a set of discrete lines, as had been heretofore accepted, due to work by Meitner and Hahn; this discovery, would have given him a place in physics history had he done nothing thereafter. Other physicists would miss its significance, but not Einstein. That Spring, he visited the lab to hear Chadwick explain in German his findings, at which time Einstein responded "I can explain either of these things, but I can't explain them both at the same time," referring to the spectrum vs. the "certain limit." This discovery has been called a "turning point" in modern physics (see Burton Feldman letter below).

.... Months later, after Britain declared war on Germany, Chadwick was interned as an enemy alien in racehorse stables west of Berlin; throughout this ordeal he suffered from malnutrition, leaving him in poor health for much of the rest of his life. The Germans did allow him to continue his research, and he employed, among other things, German radioactive toothpaste! Besides, he did thus escape the fate of many in his generation, who had to endure the horrors of trench warfare; he would feel some guilt for gaining this bit of luck, such as it was.
.... Liberated after the 1918 armistice, he was swiftly hired by Rutherford at the Cavendish Laboratory, Cambridge. There Chadwick succeeded in proving the correctness of Rutherford's theory, that an element's atomic number is equal to the charge of its nucleus, ie. that protons exist. He received his Ph.D. in 1921, and that year brought his second major contribution, when he and E.S. Bieler determined that some "strong force" holds the nucleus together, a force distinct from the electromagnetism which had been up until then presumed to be achieving this holding effect; the search since WWII for a "theory of everything" tries to account for the relationship between this force, "the weak force," gravity, and electromagnetism. This achievement is considered one of the few dozen milestones in the history of quantum physics. (Again, see Feldman letter)
.... In 1923 Chadwick was named Cavendish's (first ever) Assistant Director of Physics Research, becoming the de facto Director as Rutherford aged. In 1925 he married Aileen Stewart-Brown, daughter of a prominent stockbroker on the Liverpool exchange; in 1927 were born twin daughters, with Chadwick earning a reputation as a committed father, balanced with his growing responsibilities to science and society. After searching eight years, and, in 1932, "working day and night for three legendary weeks," (as put by the official historian of the British Atomic Energy Authority) he discovered the neutron in 1932, and, largely for this achievement, would always be known as the ideal experimentalist; this discovery is generally considered to be one of the 100 most significant events in the history of science, and made Page One of the New York Times. Madame Curie's daughter might have preceded Chadwick in this, but she incorrectly interpreted her results. (see Special Section "Significance of a Discovery of Neutron in 1932, later" below.) He was renowned, with all at Cambridge who assisted him, for being meticulous in sharing credit for this achievement. He obtained a patent for this discovery, but would allow governments and universities use the neutron for free, but his estate gets a penny for every 1020> neutrons used by commercial reactors to create fission. As it was, this discovery is understood to have transformed physics, since subsequently, protons and neutrons came to be seen as being held together by a newly understood force, the Strong Force.
.... His Nobel Prize was presented only three years after the discovery which it honored; only a handful of physics Nobels were ever awarded so soon after the feats for which the Prizes were earned. The family's trip to Stockholm for the ceremony, as one might expect, put all members "in a state of high excitement." In 1935 Chadwick left Cambridge for the University of Liverpool, where he used his Nobel Prize money toward buying a cyclotron. This machine, invented at Berkeley, U.S.A. by his friend, Ernest Lawrence, could accelerate sub-atomic particles much faster than was heretofore possible; Chadwick hoped that this device, ready in July 1939, might facilitate efficient reduction of tumors. Neutron therapy against cancer was always close to his heart, a fact verified to us at Outstanding Awards by his daughter Judith in a March 2000 letter. He already was, as of February 1938, one of a six-man Liverpool Cancer Commission.

 

Credit for Manhattan Project's Success:  Einstein, Oppenheimer, Chadwick

                                          Lyman Briggs with Einstein

... After the start of WWII, he was asked, by the Secretary of the U. K. Department of Scientific and Industrial Research, to explore the possibility of building an A-bomb; Chadwick thus became chief scientific advisor to the group of British officials weighing the option of investing much of Britain's limited resources in development of a Bomb. He would work on Bomb-related matters for the rest of the war, initially under unheard-of conditions by contemporary scientific standards.
.... While Einstein deserves to be seen as the great-grandfather of the Bomb, (owing to e=mc2) Chadwick should be seen as the grandfather or (according to "How the Bomb's creator learned to love the United States," a British review of Dr. Andrew Brown's major biography of Chadwick, The Neutron and the Bomb) the father; Oppenheimer, known in the U.S. as the father of the Bomb, would have remained unknown but for Chadwick's MAUD Report , before which, Oppenheimer later conceded, the U.S. program was a series of desultory committees (which could not make a case to FDR sufficient to persuade him to authorize the massive expenditure required to bring the Manhattan Project to fruition). As pointed out by the "Manhattan Project" page of the web site of the American Museum of Natural History in New York's Einstein exhibit, Einstein was excluded from the Project due to security concerns arising from his Leftist views, so his famous1939 letter to FDR would be the extent of his contribution to the Project; probably Einstein's love for interacting with the media also increased the security risks of his possible inclusion. (His Nobel Prize and other important objects are being exhibited in conjunction with the Hebrew University of Jerusalem.) Actually, even this Einstein contribution is overrated; this 1939 letter led only to the formation of a Uranium Committee chaired by a bureaucrat, Lyman Briggs, whose knowledge of physics would be quite inadequate. Moreover, the venerable McGeorge Bundy agrees with ace American physicist Arthur Compton that "things would have gone faster if Einstein had never written ..." to FDR; this view owes to the fact that the U.S. uranium committee, set up by FDR after Einstein's letter, valued security over scientific progress, and thus excluded foreign-born physicists, including Einstein, and led native-born physicists to presume that all that could be done was being done.
. All in all, British contributions to the Manhattan Project are not given their due in the U.S., as far as British writers are concerned; this much is conceded by Ferenc Szasz of the U. of New Mexico, who, in British Scientists and the Manhattan Project, argues that the significance of this contribution was matched only by the significance of 1): U.S. money, 2) Oppenheimer's ability to inspire, and 3) Project commander Gen. Leslie Groves' drive. The only U.S. statesman to give the British their due was Bundy, particularly in his chapters on "How the Americans Went First" and "The Americans and Their Wartime Allies" in his book Danger and Survival: Choices about the Bomb in the First Fifty Years, which makes fascinating reading; these chapters would be worth reproducing in full here were this web page not devoted so specifically to Chadwick, who Bundy called "preeminent among British nuclear physicists" in WWII. The only major aspect of Chadwick's reputation not referred to by Bundy was Chadwick's ability to set an example as a team player who avoided fame.

   
            Chadwick's Contributions to Manhattan Project's Success

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