The Making of the Atomic Bomb

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• His interest in radioactivity may have been aroused by his father, a chemistry p whole source

  His interest in radioactivity may have been aroused by his father, a chemistry professor; “probably the most important problem before

• Bohr insisted that we would never succeed in producing nuclear energy and he als whole source

  Bohr insisted that we would never succeed in producing nuclear energy and he also insisted that secrecy must never be

• As Fermi’s team had discovered in Rome in 1934, hydrogen was more efficient than whole source

  As Fermi’s team had discovered in Rome in 1934, hydrogen was more efficient than any other element at slowing down

• “He was impressed and he was concerned whole source

  “He was impressed and he was concerned.”1167 Both Teller and Wigner, Szilard wrote in a background memorandum in 1941, “shared

• Einstein had met Queen Elizabeth in 1929 on a trip to Antwerp to visit his uncle whole source

  Einstein had met Queen Elizabeth in 1929 on a trip to Antwerp to visit his uncle; thereafter the physicist and

• He contributed economics text to Franklin Roosevelt’s campaign speeches in 1932; whole source

  He contributed economics text to Franklin Roosevelt’s campaign speeches in 1932; beginning in 1933 he worked for three years for

• “Our social system is such,” he told a Senate committee in 1945, “that any publi whole source

  “Our social system is such,” he told a Senate committee in 1945, “that any public figure [is] punch-drunk with printer’s

• on September 1, 1939, and precipitated the Second World War whole source

  on September 1, 1939, and precipitated the Second World War.

• Revulsion against the bombing of cities had grown in the United States since at whole source

  Revulsion against the bombing of cities had grown in the United States since at least the Japanese bombing of Shanghai

• The War Office would take over the Kaiser Wilhelm Institute of Physics, finished whole source

  The War Office would take over the Kaiser Wilhelm Institute of Physics, finished in 1937 and beautifully equipped.

• In a 1978 memoir von Weizsäcker remembers discussing the possibility of a bomb w whole source

  In a 1978 memoir von Weizsäcker remembers discussing the possibility of a bomb with Otto Hahn in the spring of

• Sachs had intentionally listed the peaceful potentials of fission first and seco whole source

  Sachs had intentionally listed the peaceful potentials of fission first and second among its prospects.1218 To emphasize the “ambivalence” o…

• The Bureau of Standards, established by Act of Congress in 1901, is the nation’s whole source

  The Bureau of Standards, established by Act of Congress in 1901, is the nation’s physics laboratory, charged with applying science

• I’d never had such a pleasant life, ever—this concentrated five hours work every whole source

  I’d never had such a pleasant life, ever—this concentrated five hours work every night.”1246 Through the spring of 1939, in

• Most of the region had whole source

  It had seen the light of day before, most notably in an August 5, 1939, letter from Member of Parliament

• He would be naturalized as a British citizen in February 1940, but until then he whole source

  He would be naturalized as a British citizen in February 1940, but until then he was technically an enemy alien.

• * * * Werner Heisenberg sent his considered conclusions to the German War Offic whole source

  * * * Werner Heisenberg sent his considered conclusions to the German War Office on December 6, 1939, while Fermi

• Auer delivers first ton of uranium oxide to War Office whole source

  Auer, the thorium specialists, purveyors of gas mantles and radioactive toothpaste, delivered the first ton of pure uranium oxide processed

• Soviet physicists report spontaneous fission of uranium whole source

  Two associates of Soviet physicist Igor Kurchatov reported to the Physical Review in June 1940 that they had observed rare

• Japan begins military atomic bomb studies whole source

  Japanese studies toward an atomic bomb began first within the military.1285 The director of the Aviation Technology Research Institute of

• “We are aware that a catastrophe might come any day,” he wrote in the midst of P whole source

  “We are aware that a catastrophe might come any day,” he wrote in the midst of Poland’s agony.1287 Catastrophe for

• I had assumed that once we had demonstrated that in the fission of uranium neutr whole source

  I had assumed that once we had demonstrated that in the fission of uranium neutrons are emitted, there would be

• It emphasized the secret German uranium research at the Kaiser Wilhelm Institute whole source

  It emphasized the secret German uranium research at the Kaiser Wilhelm Institutes, about which they had learned from the physical

• Using their numbers, Edward Teller in one of the many calculations he made durin whole source

  Using their numbers, Edward Teller in one of the many calculations he made during this period arrived at a critical

• “In the spring of 1940 it was announced that President Roosevelt would speak to whole source

  “In the spring of 1940 it was announced that President Roosevelt would speak to a Pan American Scientific Congress in

• I did not intend to go whole source

  I did not intend to go.”1320 The other event of that crucial day, May 10, 1940, reversed his intention: the

• As a young man, with a doctorate in engineering behind him jointly from MIT and whole source

  As a young man, with a doctorate in engineering behind him jointly from MIT and Harvard earned in one intense

• As a result of the German bombing of Warsaw in the autumn of 1939, an act German whole source

  As a result of the German bombing of Warsaw in the autumn of 1939, an act Germany represented as tactical

• By mid-November 13,700 tons of high explosives had fallen and 12,600 tons of inc whole source

  By mid-November 13,700 tons of high explosives had fallen and 12,600 tons of incendiary canisters, an average of 201 tons

• Only twenty-seven Londoners lost their lives to bombs in 1942 whole source

  Only twenty-seven Londoners lost their lives to bombs in 1942.

• Auer orders sixty tons of uranium oxide from Belgium whole source

  In June 1940, about the time Simon was hammering out his kitchen strainer, Auer ordered sixty tons of refined uranium

• Their interpreter, sent along from Heidelberg, turned out to be Wolfgang Gentner whole source

  Their interpreter, sent along from Heidelberg, turned out to be Wolfgang Gentner, the former Radium Institute student who had confirmed

• Nothing in the record indicates the overestimate was deliberate, but it is worth whole source

  Nothing in the record indicates the overestimate was deliberate, but it is worth noting that Walther Bothe, a protege of

• Soon after the news of the discovery of fission reached Berkeley in late January whole source

  Soon after the news of the discovery of fission reached Berkeley in late January 1939 he had devised an elegantly

• “Segré was very familiar with the chemistry of [rhenium], since he and his co-wo whole source

  “Segré was very familiar with the chemistry of [rhenium], since he and his co-workers [studying rhenium] had discovered [a similar

• “As time went on and the fission process became better understood, I found it in whole source

  “As time went on and the fission process became better understood, I found it increasingly difficult to believe that one

• Tizard Mission brings British secrets to America whole source

  Churchill had sent over Henry Tizard in the late summer of 1940 with a delegation of experts and a black-enameled

• He convinced McMillan: “I left Berkeley in November 1940 to take part in the dev whole source

  He convinced McMillan: “I left Berkeley in November 1940 to take part in the development of radar for national defense.”1384

• An attache was duly dispatched to Berkeley to scold Ernest Lawrence, the 1939 No whole source

  An attache was duly dispatched to Berkeley to scold Ernest Lawrence, the 1939 Nobel laureate in physics, for giving away

• Not until 1942 would they officially propose a name for the new element that fis whole source

  Not until 1942 would they officially propose a name for the new element that fissioned like U235 but could be

• Consistent with Martin Klaproth’s inspiration in 1789 to link his discovery of a whole source

  Consistent with Martin Klaproth’s inspiration in 1789 to link his discovery of a new element with the recent discovery of

• 12 A Communication from Britain James Bryant Conant traveled to London in the whole source

  12 A Communication from Britain James Bryant Conant traveled to London in the winter of 1941 to open a liaison

• “He thought you would be an old man with a white beard, exuding learning and aca whole source

  “He thought you would be an old man with a white beard, exuding learning and academic formality,” Brendon Bracken, Churchill’s

• In his autobiography, written late in life, he justified his participation: I d whole source

  In his autobiography, written late in life, he justified his participation: I did not see in 1917, and do not

• In 1940 Lawrence had recruited a Harvard experimentalist named Kenneth Bainbridg whole source

  In 1940 Lawrence had recruited a Harvard experimentalist named Kenneth Bainbridge, by trade a nuclear physicist—Bainbridge built the Harvard…

• Mackenzie King elected Canadian Liberal leader whole source

  In 1919, the first year of the program, he was appointed a National Research Council fellow and used the appointment

• If X rays—light—were only a motion of waves, then their wavelengths would not ha whole source

  If X rays—light—were only a motion of waves, then their wavelengths would not have changed; Compton had in fact demonstrated

• Jewett had delivered the report to Bush with a cover letter calling it “authorit whole source

  Jewett had delivered the report to Bush with a cover letter calling it “authoritative and impressive,” but privately he cautioned

• In that summer of 1941, with recollections of what I had seen and heard in Engla whole source

  In that summer of 1941, with recollections of what I had seen and heard in England fresh in my mind,

• “In the summer of 1941,” John Dunning’s associate Eugene Booth remembers, “Brigg whole source

  “In the summer of 1941,” John Dunning’s associate Eugene Booth remembers, “Briggs visited us in the basement of Pupin at

• When Hitler made his temporary pact with Stalin in 1939 it included an exchange whole source

  When Hitler made his temporary pact with Stalin in 1939 it included an exchange of prisoners, and Houtermans was handed

• The Minister of Posts, imagining himself handing Hitler the decisive secret weap whole source

  The Minister of Posts, imagining himself handing Hitler the decisive secret weapon of the war, had funded the building of

• After the summer of 1941 the German bomb program depended entirely on uranium an whole source

  After the summer of 1941 the German bomb program depended entirely on uranium and Vemork heavy water.

• In May 1941 he lectured on “Super-explosive U235,” reviewing existing knowledge whole source

  In May 1941 he lectured on “Super-explosive U235,” reviewing existing knowledge.1468, 1469 He was aware that an explosive chain reaction

• Of course, I got completely disgusted with the White Army long before it was all whole source

  Of course, I got completely disgusted with the White Army long before it was all over.” Kistiakowsky escaped to Germany

• In a memorandum Bush wrote to Conant the same day he makes it clear that the MAU whole source

  In a memorandum Bush wrote to Conant the same day he makes it clear that the MAUD Report was the

• They had chosen gaseous diffusion at dinner one evening in 1940 on their way hom whole source

  They had chosen gaseous diffusion at dinner one evening in 1940 on their way home from a trip to Schenectady

• Dunning and Urey appraise gaseous diffusion whole source

  If a chain reaction became possible with normal uranium, a smaller and probably cheaper power plant could be made with

• “It was from September 1941,” he remarks in consequence, “that we saw an open ro whole source

  “It was from September 1941,” he remarks in consequence, “that we saw an open road ahead of us, leading to

• His son Aage, a Nobel laureate in his turn and his father’s successor as directo whole source

  His son Aage, a Nobel laureate in his turn and his father’s successor as director of the Copenhagen institute, summarizes

• Bush delivers third NAS report to Roosevelt whole source

  Bush personally delivered the third National Academy of Sciences report to the President on November 27, 1941.

• The American reaction to militant Japanese expansion into Manchuria and China—as whole source

  The American reaction to militant Japanese expansion into Manchuria and China—as many as 200,000 men, women and children were brutally

• 13 The New World Enrico Fermi’s team at Columbia University had been hard at w whole source

  13 The New World Enrico Fermi’s team at Columbia University had been hard at work through 1941 while the government

• Szilard joins Columbia under NDRC contract whole source

  Szilard had finally gone on the Columbia payroll on November 1, 1940, when the $40,000 National Defense Research Committee contract

• (S-l for Section One of the Office of Scientific Research and Development: Conan whole source

  (S-l for Section One of the Office of Scientific Research and Development: Conant would administer S-l, but the National Defense

• Zhukov counterattacks German army outside Moscow whole source

  December 6, 1941, the day of the bomb program expansion, marked another tidal event: Soviet forces under General Georgi Zhukov

• “The first time large funds were available in Germany,” Heisenberg recalled at t whole source

  “The first time large funds were available in Germany,” Heisenberg recalled at the end of the war, “was in the

• “In the course of one of these meetings, at the end of April 1942, [Fromm] remar whole source

  “In the course of one of these meetings, at the end of April 1942, [Fromm] remarked that our only chance

• “On May 6, 1942, I discussed this situation with Hitler and proposed that Göring whole source

  “On May 6, 1942, I discussed this situation with Hitler and proposed that Göring be placed at the head of

• Assuming they know about [plutonium], they could run a heavy water pile for two whole source

  Assuming they know about [plutonium], they could run a heavy water pile for two months at 100,000 kw and produce

• On the other hand, we don’t plan to have bombs in production until the first par whole source

  On the other hand, we don’t plan to have bombs in production until the first part of 1944.1600 Compton encouraged

• “In 1939,” he had already written Vannevar Bush passionately in late May, before whole source

  “In 1939,” he had already written Vannevar Bush passionately in late May, before the cooling-system and contractor debates, “the Government

• * * * In the summer of 1942 Robert Oppenheimer gathered together at Berkeley a whole source

  * * * In the summer of 1942 Robert Oppenheimer gathered together at Berkeley a small group of theoretical physicists

• Hans Bethe explains energy production in stars whole source

  His most outstanding contribution, for which he would receive the 1967 Nobel Prize in Physics, was to elucidate the production

• On the recommendation of Theodor von Kármán, whom he consulted at Caltech, he an whole source

  On the recommendation of Theodor von Kármán, whom he consulted at Caltech, he and Edward Teller in 1940 extended and

• He thought such an operation might find a home in Cincinnati or with the plutoni whole source

  He thought such an operation might find a home in Cincinnati or with the plutonium production piles in Tennessee.1634 *

• It predicted enough fissionable material for a test in eighteen months—by March whole source

  It predicted enough fissionable material for a test in eighteen months—by March 1944.

• The ultimate potential possibilities are now considered to be very much greater whole source

  The ultimate potential possibilities are now considered to be very much greater than at the time of the [last] report.”1637

• “On the day I learned that I was to direct the project which ultimately produced whole source

  “On the day I learned that I was to direct the project which ultimately produced the atomic bomb,” Albany-born Leslie

• He had graduated from the University of Washington in 1914, studied engineering whole source

  He had graduated from the University of Washington in 1914, studied engineering intensely for two years at MIT and gone

• Rich Congo pitchblende shipped to the United States whole source

  Nichols told him about a recent and fortuitous discovery: some 1,250 tons of extraordinarily rich pitchblende—it was 65 percent uranium

• * * * Enrico Fermi began planning a full-scale chain-reacting pile in May 1942 whole source

  * * * Enrico Fermi began planning a full-scale chain-reacting pile in May 1942 when one of the exponential piles

• And added what he took to be a clinching argument: “If we were successful in tim whole source

  And added what he took to be a clinching argument: “If we were successful in time, we would shorten the

• Discovery of delayed neutrons in fission whole source

  The “most significant fact assuring us that the chain reaction could be controlled,” says Compton, was one of the Richard

• 14 Physics and Desert Country Robert Oppenheimer was thirty-eight years old in whole source

  14 Physics and Desert Country Robert Oppenheimer was thirty-eight years old in 1942.

• Edward Teller first met Oppenheimer in 1937 whole source

  Edward Teller first met Oppenheimer in 1937.

• Oppenheimer’s mother died after a long battle with leukemia in late 1931; that w whole source

  Oppenheimer’s mother died after a long battle with leukemia in late 1931; that was when he announced himself to Herbert

• He asked Rabi only to participate in an inaugural physics conference at Los Alam whole source

  He asked Rabi only to participate in an inaugural physics conference at Los Alamos in April 1943 and to help

• I think you just cannot get to that level unless you are somewhat introverted whole source

  I think you just cannot get to that level unless you are somewhat introverted.” (Luis Alvarez, the 1968 physics Nobel

• The necessity of “scientific autonomy” was one crucial reason they cited for res whole source

  The necessity of “scientific autonomy” was one crucial reason they cited for resisting militarization, Oppenheimer wrote Conant at the begin…

• Norwegian commandos parachute for Vemork sabotage whole source

  This time six men, Norwegians native to the region and trained as Special Forces, parachuted onto a frozen lake thirty

• * * * In Japan both the Army Air Force and the Imperial Navy had moved separate whole source

  * * * In Japan both the Army Air Force and the Imperial Navy had moved separately since 1941 to

• In the spring of 1942 the Navy committed itself to developing nuclear power for whole source

  In the spring of 1942 the Navy committed itself to developing nuclear power for propulsion: The study of nuclear physics

• Japanese colloquium deems atomic bomb impractical whole source

  The Japanese physics colloquium in Tokyo had decided in March 1943 that an atomic bomb was possible but not practically

• There was “relatively little nuclear physics” at Los Alamos, Bethe says, mostly whole source

  There was “relatively little nuclear physics” at Los Alamos, Bethe says, mostly cross-section calculations.1802 They thought they were assem…

• “If there were any ground-breaking ceremonies at Los Alamos like champagne or cu whole source

  “If there were any ground-breaking ceremonies at Los Alamos like champagne or cutting ribbons,” John Manley comments, “I was unaware

• Edward Condon, whose father had been a builder of railroads in the West, who had whole source

  Edward Condon, whose father had been a builder of railroads in the West, who had worked as a newspaper reporter

• In July 1940, in the desperate time after the debacle of Dunkirk and at the begi whole source

  In July 1940, in the desperate time after the debacle of Dunkirk and at the beginning of the Battle of

• We must be able to overwhelm them by this means, without which I do not see a wa whole source

  We must be able to overwhelm them by this means, without which I do not see a way through.”1816, 1817

• It was an enchantingly beautiful summer night whole source

  It was an enchantingly beautiful summer night.”1825 Pathfinders started dropping yellow markers and bombs at fifty-five minutes past midnigh…

• I had never seen a fire like that before and was never to see its like again whole source

  I had never seen a fire like that before and was never to see its like again.1827 The summer heat

• Hamburg firestorm kills 45,000 in one night whole source

  The smallest children lay like fried eels on the pavement.1831 Bomber Command killed at least 45,000 Germans that night, the

• “In this experiment,” says the Los Alamos technical history, “the neutron number whole source

  “In this experiment,” says the Los Alamos technical history, “the neutron number was measured from an almost invisible speck of

• “I wonder why whole source

  “I wonder why?”) Too much peace and quiet at a guest ranch threatened to exhaust him further and on July

• “Deke” Parsons, a 1922 Annapolis graduate then responsible under Bush for field- whole source

  “Deke” Parsons, a 1922 Annapolis graduate then responsible under Bush for field-testing the proximity fuse.1 Parsons had also worked on

• whole source

  .1852, 1853 For security reasons, these were called by the Air Force representatives the ‘Thin Man’ and the ‘Fat Man,’

• Modification of the first B-29 officially began November 29, 1943 whole source

  Modification of the first B-29 officially began November 29, 1943.” * * * A captain of the Danish Army who

• But it was also mentioned that there were special problems in which his co-opera whole source

  But it was also mentioned that there were special problems in which his co-operation would be of considerable help.”1855 Bohr

• He emphasizes Bohr’s developing understanding then with a potent simile: “It cam whole source

  He emphasizes Bohr’s developing understanding then with a potent simile: “It came to him as a revelation, very much as

• By running it continuously for a month his crews produced a partially separated whole source

  By running it continuously for a month his crews produced a partially separated 100-microgram sample of U235.1877 That was several

• Berkeley could promise only 5 grams of enriched uranium per day per racetrack, b whole source

  Berkeley could promise only 5 grams of enriched uranium per day per racetrack, but Groves thought 2,000 tanks well beyond

• By August, twenty thousand construction workers swarmed over the area whole source

  By August, twenty thousand construction workers swarmed over the area.1880, 1881 An experimental Alpha unit saw successful operation.

• The Army had contracted with Tennessee Eastman, a manufacturing subsidiary of Ea whole source

  The Army had contracted with Tennessee Eastman, a manufacturing subsidiary of Eastman Kodak, to operate the electromagnetic separation plant…

• “The first lay in the design,” writes Groves, “which placed the heavy current-ca whole source

  “The first lay in the design,” writes Groves, “which placed the heavy current-carrying silver bands too close together.1886 The other

• * * * Gaseous-diffusion research had progressed at Columbia University since Jo whole source

  * * * Gaseous-diffusion research had progressed at Columbia University since John Dunning and Eugene Booth had first demonstrated measurable

• Urey saw the point and withdrew; “from that time forward,” write his colleague b whole source

  Urey saw the point and withdrew; “from that time forward,” write his colleague biographers, “his energies were directed to the

• If because of some unknown and unanticipated factor a reactor were to explode an whole source

  If because of some unknown and unanticipated factor a reactor were to explode and throw great quantities of highly radioactive

• When they had burned long enough—100 days—to transmute about 1 atom in every 4,0 whole source

  When they had burned long enough—100 days—to transmute about 1 atom in every 4,000 into plutonium the irradiated slugs could

• And to deny it to others, even to the British until Winston Churchill turned Fra whole source

  And to deny it to others, even to the British until Winston Churchill turned Franklin Roosevelt’s head at the conference

• * * * Work toward an atomic bomb had begun in the USSR in 1939 whole source

  * * * Work toward an atomic bomb had begun in the USSR in 1939.

• Equipment, instruments and books were packed up, and valuable records shipped ea whole source

  Equipment, instruments and books were packed up, and valuable records shipped east for safety.”1908 The invasion rearranged research priorit…

• Compton sent Szilard’s request to Lyman Briggs, whose responsibilities within th whole source

  Compton sent Szilard’s request to Lyman Briggs, whose responsibilities within the OSRD included patent matters; Briggs thought the Army ough…

• which were made before government support for this research was forthcoming whole source

  which were made before government support for this research was forthcoming.”1922 The patent could be registered in his name alone

• The matter is thus one of real importance to our Government whole source

  The matter is thus one of real importance to our Government.”1924 Before Washington could respond Szilard had to fight off

• He knew fifteen people, he told Bush, “who at one time or another felt so strong whole source

  He knew fifteen people, he told Bush, “who at one time or another felt so strongly about [compartmentalization] that they

• This was not done in the past [in the Manhattan Project] and it is not being don whole source

  This was not done in the past [in the Manhattan Project] and it is not being done at present.”1938 He

• Perhaps influenced by the enthusiasm he found at Los Alamos for weapons-making, whole source

  Perhaps influenced by the enthusiasm he found at Los Alamos for weapons-making, he proposed at the time of the April

• Sir John Anderson, Chancellor of the Exchequer, a scientist and the member of Ch whole source

  Sir John Anderson, Chancellor of the Exchequer, a scientist and the member of Churchill’s cabinet responsible for the Tube Alloys

• Bohr escapes to Scotland with Heisenberg's reactor drawing whole source

  When Niels Bohr escaped from Stockholm to Scotland on October 6, 1943, he carried with him Werner Heisenberg’s drawing of

• Word came by way of clandestine shortwave radio from the Rjukan area on February whole source

  Word came by way of clandestine shortwave radio from the Rjukan area on February 9, 1944, that the heavy water

• Kurt Diebner of German Army Ordnance counted the full effect on German fission r whole source

  Kurt Diebner of German Army Ordnance counted the full effect on German fission research of the Vemork bombing and the

• it will be seen that it was the elimination of German heavy-water production in whole source

  it will be seen that it was the elimination of German heavy-water production in Norway that was the main factor

• Halsey would write in a memoir, “the South Pacific was only a stepchild whole source

  Halsey would write in a memoir, “the South Pacific was only a stepchild.”1962 But Americans also found it difficult at

• Unconditional surrender becomes official Allied policy whole source

  We had so much trouble getting those two French generals together that I thought to myself that this was as

• A succession of trains delivered them into a fantastic landscape—Frisch and anot whole source

  A succession of trains delivered them into a fantastic landscape—Frisch and another man in December, the larger group early in

• Bethe and Teller prepared the consequent report, “Explosion of an inhomogeneous whole source

  Bethe and Teller prepared the consequent report, “Explosion of an inhomogeneous uranium-heavy water pile.”1984, 1985 It found that such an

• But his real function, I think for almost all of us, was not the technical one whole source

  But his real function, I think for almost all of us, was not the technical one.”1987 Here two texts of

• He responded candidly with loyalty to his British counterpart, Bohr adds: “F als whole source

  He responded candidly with loyalty to his British counterpart, Bohr adds: “F also informed B that as soon as the

• Frankfurter implies this understanding: “I wrote out such a formula for Bohr to whole source

  Frankfurter implies this understanding: “I wrote out such a formula for Bohr to take to London—a communication to Sir John

• At the end of March 1944, Bohr seemingly had a mandate from the President of the whole source

  At the end of March 1944, Bohr seemingly had a mandate from the President of the United States to talk

• It is a sad story whole source

  It is a sad story.”2017 Bohr wrote Churchill on May 22; the letter was circumspect but political after all and

• The scientists who are brought into confidence can only offer the statesmen all whole source

  The scientists who are brought into confidence can only offer the statesmen all such information about technical matters as may

• During the talk the President had expressed the wish to see B, and as a prelimin whole source

  During the talk the President had expressed the wish to see B, and as a preliminary step F advised B

• Notice that Bohr does not propose a world government of centralized authority bu whole source

  Notice that Bohr does not propose a world government of centralized authority but a consortium: “An open world where each

• of what concessions the various powers are prepared to make as their contributio whole source

  of what concessions the various powers are prepared to make as their contribution to an adequate control arrangement, [will it]

• Bohr worried through the hot night and composed another apology the next day: “I whole source

  Bohr worried through the hot night and composed another apology the next day: “I have had serious anxieties,” he confided,

• whole source

  .2051 He resented even more that he was removed [by lack of administrative contact] from Oppenheimer.” The theoretical complexity of

• “When Los Alamos was established in the spring of 1943,” he writes and the techn whole source

  “When Los Alamos was established in the spring of 1943,” he writes and the technical history of the laboratory confirms,

• You have to have a gun emplacement, and a gun, and a sand butt, which is nothing whole source

  You have to have a gun emplacement, and a gun, and a sand butt, which is nothing but a huge

• “Both because of the theoretical problems still to be solved and because of the whole source

  “Both because of the theoretical problems still to be solved and because of the possibility that the Super would have

• “The hydrodynamical problem was simply stated,” Ulam comments, “but very difficu whole source

  “The hydrodynamical problem was simply stated,” Ulam comments, “but very difficult to calculate—not only in detail, but even in order

• The IBM equipment arrived early in April 1944 and the Theoretical Division immed whole source

  The IBM equipment arrived early in April 1944 and the Theoretical Division immediately put it to good use running brute-force

• At the present time the method to which an over-riding priority must be assigned whole source

  At the present time the method to which an over-riding priority must be assigned is the method of implosion.”2081 That

• “The Laboratory had at this time strong reserves of techniques, of trained manpo whole source

  “The Laboratory had at this time strong reserves of techniques, of trained manpower, and of morale,” says the technical history.2083

• He was extremely suspicious of me whole source

  He was extremely suspicious of me.2084 Parsons had his hands full in any case designing the uranium gun, Little Boy,

• I remember that I met the man at the old Warner Theater here in Washington, up i whole source

  I remember that I met the man at the old Warner Theater here in Washington, up in the balcony—real cloak

• This vital information the BuOrd man carried to Los Alamos and passed along to E whole source

  This vital information the BuOrd man carried to Los Alamos and passed along to Edward Teller.2094 Teller in turn briefed

• suddenly told me that we had [made] a terrible scientific blunder,” Groves testi whole source

  suddenly told me that we had [made] a terrible scientific blunder,” Groves testified after the war.2095 “I think he was

• Largest atomic pile yet assembled is completed whole source

  But after a couple of seconds he relaxed, realizing that under no circumstances could natural uranium and natural wood in

• Groves was enthusiastic enough at year’s end to report to George Marshall that h whole source

  Groves was enthusiastic enough at year’s end to report to George Marshall that he expected to have eighteen 5-kilogram plutonium

• 17 The Evils of This Time The bombs James Bryant Conant speculated about early whole source

  17 The Evils of This Time The bombs James Bryant Conant speculated about early in 1945 were crude designs of

• During the summer of 1944, Conant says, on an earlier inspection trip to Los Ala whole source

  During the summer of 1944, Conant says, on an earlier inspection trip to Los Alamos, he and Bush had found

• Robert Oppenheimer also committed himself at that time to exploring the thermonu whole source

  Robert Oppenheimer also committed himself at that time to exploring the thermonuclear—after the war was won—in a letter to Richard

• Such understanding justified the work at Los Alamos if anything did, and the wor whole source

  Such understanding justified the work at Los Alamos if anything did, and the work in turn healed the split between

• As early as June 1945 whole source

  Early in 1945 it adapted its techniques to partial spheres and eventually to spheres surrounded by HE lens systems with

• Not until mid-December 1944 did a lens test look promising; the eighteen 5-kilog whole source

  Not until mid-December 1944 did a lens test look promising; the eighteen 5-kilogram bombs Groves told George Marshall he hoped

• In February 1945 Kistiakowsky chose an explosive called Composition B to serve a whole source

  In February 1945 Kistiakowsky chose an explosive called Composition B to serve as the fast-burning component of Fat Man’s lenses

• After the Imperial Navy had bowed out of atomic energy research Yoshio Nishina h whole source

  After the Imperial Navy had bowed out of atomic energy research Yoshio Nishina had continued patriotically to pursue it even

• Otto Frisch had tried gaseous thermal diffusion (differing from Philip Abelson’s whole source

  Otto Frisch had tried gaseous thermal diffusion (differing from Philip Abelson’s liquid thermal diffusion) at Birmingham early in 1941 and

• Nishina did not meet again with Nobuuji until seven months later, in February 19 whole source

  Nishina did not meet again with Nobuuji until seven months later, in February 1944, when he reported difficulty producing uranium

• More recently he had been test-piloting the B-29, which in 1944 was just beginni whole source

  More recently he had been test-piloting the B-29, which in 1944 was just beginning to come on line, working with

• He flew to Second Air Force headquarters in Colorado Springs at the beginning of whole source

  He flew to Second Air Force headquarters in Colorado Springs at the beginning of September 1944 to report to commanding

• As early as September 1939 they proposed its use from bases in the Philippines, whole source

  As early as September 1939 they proposed its use from bases in the Philippines, Siberia or the Aleutians in the

• He won his wings in 1929 and never looked back: mess officer, navigation officer whole source

  He won his wings in 1929 and never looked back: mess officer, navigation officer, General Headquarters navigator, B-10’s, B-17’s.

• In England in 1943 and 1944 he worked night and day to improve precision bombing whole source

  In England in 1943 and 1944 he worked night and day to improve precision bombing.

• It was the end of 1944 and he was feeling the pressure of accumulating Manhattan whole source

  It was the end of 1944 and he was feeling the pressure of accumulating Manhattan Project delays: “General Groves indicated

• They flew toward a city that an Associated Press correspondent who knew it well whole source

  They flew toward a city that an Associated Press correspondent who knew it well had described in 1943 in a

• Firebombing of Tokyo whole source

  Tokyo on the night of March 9-10, 1945

• Nagoya firebombing whole source

  firebombed Nagoya on March 11

• Osaka firebombing whole source

  firebombed Osaka by radar on March 13

• They thought they were assembled to engineer a “practical military weapon. whole source

  os, Bethe says, mostly cross-section calculations.1802 They thought they were assembled to engineer a “practical military weapon.” That was…

• it overestimated the difficulty of isotope separation and underestimated U. whole source

  essentially technological. Like Bohr’s assessment in 1939, it overestimated the difficulty of isotope separation and underestimated U.S. ind…

• that an atomic bomb was possible but not practically attainable by any of the belligerents in time t whole source

  physics colloquium in Tokyo had decided in March 1943 that an atomic bomb was possible but not practically attainable by any of the belliger…

• He was an exceptional theoretician; he and Oppenheimer had boarded together at Göttingen; Condon tho whole source

  ’s party to satirize Los Alamos’ Panglossian mood.1815 He was an exceptional theoretician; he and Oppenheimer had boarded together at Göttin…

• 1817 The slide from precision bombing attacks on industry to general attacks on cities followed les whole source

  means, without which I do not see a way through.”1816, 1817 The slide from precision bombing attacks on industry to general attacks on citie…

• that “the targets chosen were in congested industrial areas and were carefully picked so that bombs whole source

  oirs of this transitional period in the summer of 1941 that “the targets chosen were in congested industrial areas and were carefully picked…

• Pathfinders started dropping yellow markers and bombs at fifty-five minutes past midnight on July 28 whole source

  . It was an enchantingly beautiful summer night.”1825 Pathfinders started dropping yellow markers and bombs at fifty-five minutes past midni…

• The summer heat and low humidity, the mix of high-explosive and incendiary bombs that made kindling whole source

  e that before and was never to see its like again.1827 The summer heat and low humidity, the mix of high-explosive and incendiary bombs that…

• Bomber Command killed at least 45,000 Germans that night, the majority of them old people, women and whole source

  lest children lay like fried eels on the pavement.1831 Bomber Command killed at least 45,000 Germans that night, the majority of them old pe…

• of Alessandro Volta, the Como-born Italian physicist who invented the electric battery and after who whole source

  congress commemorated the centennial of the death in 1827 of Alessandro Volta, the Como-born Italian physicist who invented the electric bat…

• The experiment thus established what had not yet been confirmed despite the expensive rush of buildi whole source

  found to be somewhat greater even than for U235.”1836 The experiment thus established what had not yet been confirmed despite the expensive…

• Compartmentalization put Los Alamos off limits. whole source

  ved to the adobe-style La Fonda Hotel in Santa Fe.1837 Compartmentalization put Los Alamos off limits. The Seaborgs were ready to return to…

• Oppenheimer interviewed the man for the job in Washington and agreed. whole source

  ral says, “I was sure he was the man for the job.”1841 Oppenheimer interviewed the man for the job in Washington and agreed. Parsons was mar…

• 1 Spontaneous fission, a relatively rare nuclear event, differs from fission caused by neutron bomba whole source

  rom fission research in August 1940 to develop it.1842 1 Spontaneous fission, a relatively rare nuclear event, differs from fission caused b…

• discovery and before Rutherford’s announcement to Geiger at Christmastime 1910 that he had worked ou whole source

  place sometime prior to July 1910—after Marsden’s 1909 discovery and before Rutherford’s announcement to Geiger at Christmastime 1910 that h…

• Bohr understood that Chadwick might be hinting about work on nuclear fission. whole source

  h his co-operation would be of considerable help.”1855 Bohr understood that Chadwick might be hinting about work on nuclear fission. The Dan…

• died that day of Szilard’s filing, July 4, 1934, in Savoy. whole source

  ska Curie, born in Warsaw, Poland, on November 7, 1867, died that day of Szilard’s filing, July 4, 1934, in Savoy. Einstein’s was the best e…

• as a series of unusual spectral lines twenty-three years before it was discovered mixed into uranium whole source

  ium was discovered in the chromosphere of the sun in 1868 as a series of unusual spectral lines twenty-three years before it was discovered…

• Einstein explains the photoelectric effect whole source

  la. Someone else did: Albert Einstein. In a paper in 1905 that eventually won for him the Nobel Prize, Einstein connected Planck’s idea of l…

• and the abolition of the feudal clan system transformed Hiroshima fief into Hiroshima Prefecture and whole source

  ended hand. The restoration of the Meiji emperor in 1868 and the abolition of the feudal clan system transformed Hiroshima fief into Hiroshi…

• “Hiroshima was a city of considerable military importance. whole source

  rld War, an American study noted in the autumn of 1945, “Hiroshima was a city of considerable military importance. It contained the 2nd Army…

• Robert Oppenheimer pitches his summary closer to the shock of surprise a refugee released from the s whole source

  an my father had expected,” Aage Bohr understates.1873 Robert Oppenheimer pitches his summary closer to the shock of surprise a refugee rele…

• That was several hundred million times less than the 100 kilograms Robert Oppenheimer had originally whole source

  partially separated 100-microgram sample of U235.1877 That was several hundred million times less than the 100 kilograms Robert Oppenheimer…

• Five grams per day per racetrack with only five racetracks would mean 1,200 days per 30-kilogram bom whole source

  ntially higher production rates would be assured.”1878 Five grams per day per racetrack with only five racetracks would mean 1,200 days per…

• electromagnetic separation still looked so much more promising to James Bryant Conant than either th whole source

  its laboratory predecessors had hardly done. Yet in 1942 electromagnetic separation still looked so much more promising to James Bryant Cona…

• by lobbing a hail of small bombs into his open carriage in broad daylight on a main street of St. whole source

  he People’s Will”—murdered Alexander on March 13, 1881, by lobbing a hail of small bombs into his open carriage in broad daylight on a main…

• discovery of “electric waves”—radio, we call the phenomenon now—had impressed Rutherford wonderfully whole source

  n 1893 stayed on to earn a B.Sc. Heinrich Hertz’s 1887 discovery of “electric waves”—radio, we call the phenomenon now—had impressed Rutherf…

• who called themselves physicists and the larger, associated network of chemists. whole source

  t one thousand men and women throughout the world in 1895 who called themselves physicists and the larger, associated network of chemists.11…

• It had not been solved when Groves committed the Manhattan Project to a $100 million gaseous-diffusi whole source

  ow feel confident that the problem can be solved.”1890 It had not been solved when Groves committed the Manhattan Project to a $100 million…

• Harold Urey could note in a progress report that “three methods for the separation of the uranium is whole source

  235 separation in November 1941. By the spring of 1942 Harold Urey could note in a progress report that “three methods for the separation of…

• * * * Twelve days after Enrico Fermi proved the chain reaction in Chicago on December 2, 1942, Grov whole source

  e control of atomic energy, not its applications.”1892 * * * Twelve days after Enrico Fermi proved the chain reaction in Chicago on December…

• Better to site plutonium production somewhere far away. whole source

  agnetic and gaseous-diffusion plants “inoperable.”1893 Better to site plutonium production somewhere far away. The production piles needed p…

• Groves could hardly build Hanford until he knew more about the plant that would go there. whole source

  ings and gave the Hanford Engineer Works its name.1895 Groves could hardly build Hanford until he knew more about the plant that would go th…

• Rontgen discovers X-rays whole source

  work had abruptly offered itself. On November 8, 1895, one month after Rutherford arrived at Cambridge, the German physicist Wilhelm Röntgen…

• Thomson identifies the electron whole source

  th cathode rays, experiments that would culminate in 1897 in his identification of what he called the “negative corpuscle”—the electron, the…

• Thomson demonstrated that the beam of glowing matter in a cathode-ray tube was not made up of light whole source

  s the television tube of today. In the spring of 1897 Thomson demonstrated that the beam of glowing matter in a cathode-ray tube was not mad…

• when Rutherford first turned his attention to the phenomenon Henri Becquerel found and which Marie C whole source

  , had their backbreaking work.136 * * * Between 1898, when Rutherford first turned his attention to the phenomenon Henri Becquerel found and…

• Rutherford discovers thorium radioactive emanation whole source

  of its kind in the world, I cannot complain.” In 1900 Rutherford reported the discovery of a radioactive gas emanating from the radioactive…

• Rutherford and Soddy calculate radioactive decay energy whole source

  and thorium ores; now he knew why. An important 1903 paper written with Soddy, “Radioactive change,” offered the first informed calculations…

• by bombarding elements with cathode rays. whole source

  physicist Philipp Lenard had demonstrated as much in 1903 by bombarding elements with cathode rays.168 Lenard dramatized his findings with a…

• before going to the Technische Hochschule in Berlin in 1904 and on to work with Fritz Haber and then whole source

  on to Göttingen in 1906; de Hevesy tried Budapest in 1903 before going to the Technische Hochschule in Berlin in 1904 and on to work with Fr…

• Nobel laureate Philipp Lenard, seeing relativity hailed and Einstein come to fame, retreated into a whole source

  sts for the Preservation of Pure Scholarship. The 1905 Nobel laureate Philipp Lenard, seeing relativity hailed and Einstein come to fame, re…

• the secondings increasing in number after 1917; Max Planck, who was not given to exaggeration, wrote whole source

  ed for the Nobel Prize in all but two years since 1910, the secondings increasing in number after 1917; Max Planck, who was not given to exa…

• Meitner had met Albert Einstein for the first time at a scientific conference in Salzburg. whole source

  maller energy releases. When she was thirty-one, in 1909, Meitner had met Albert Einstein for the first time at a scientific conference in S…

• Rutherford announced the arrival: “Bohr, a Dane, has pulled out of Cambridge and turned up here to g whole source

  ester. Writing to an American friend on March 18, 1912, Rutherford announced the arrival: “Bohr, a Dane, has pulled out of Cambridge and tur…

• meeting of the British Association, the separation of neon into two isotopes by laborious diffusion whole source

  in Cambridge. It was he who had announced, at the 1913 meeting of the British Association, the separation of neon into two isotopes by labor…

• when he separated two isotopes of neon by diffusing a mixed sample several thousand times over and o whole source

  r gases. Francis Aston had applied this principle in 1913 when he separated two isotopes of neon by diffusing a mixed sample several thousan…

• an act Germany represented as tactical because the Polish city was heavily fortified, the British Ai whole source

  of the German bombing of Warsaw in the autumn of 1939, an act Germany represented as tactical because the Polish city was heavily fortified,…

• Franz Simon, now officially working for the MAUD Committee, produced a report nearly as crucial to t whole source

  ir lives to bombs in 1942. At Oxford in December 1940, Franz Simon, now officially working for the MAUD Committee, produced a report nearly…

• Weizmann found a circular on his desk from the British War Office “inviting every scientist in posse whole source

  eturning to Manchester from France in late August 1914, Weizmann found a circular on his desk from the British War Office “inviting every sc…

• had questioned a witness at an appropriations hearing, “What is a physicist? whole source

  tended into the laboratory as well. A congressman in 1914 had questioned a witness at an appropriations hearing, “What is a physicist? I was…

• the United States counted about 2,500 physicists, three times as many as in 1919. whole source

  ation Board or the new Guggenheim fellowships. By 1932 the United States counted about 2,500 physicists, three times as many as in 1919. The…

• Wells' The World Set Free predicts atomic war whole source

  1. English novelist H. G. Wells. His 1914 novel, The World Set Free, predicted atomic bombs, atomic war and world government. 2. As a young…

• Enrico Fermi, Werner Heisenberg and Wolfgang Pauli (l. whole source

  14. Niels Bohr in the 1920s. 15. At Como, Italy, in 1927, Enrico Fermi, Werner Heisenberg and Wolfgang Pauli (l. to r.) heard Bohr define co…

• opened the atomic nucleus to detailed examination. whole source

  tégé James Chadwick. The discovery of the neutron in 1932 opened the atomic nucleus to detailed examination. Chadwick’s colleagues hailed hi…

• General relativity explains Mercury's orbit anomaly whole source

  rior” that left him giddy. Thus also, in November 1915, Einstein’s extreme reaction when he realized that the general theory of relativity h…

• in an artillery bombardment against the British at Ypres. whole source

  he Germans first used it on the night of July 17, 1917, in an artillery bombardment against the British at Ypres. The attack came as a compl…

• began the first effective and sustained campaign of strategic civilian bombardment. whole source

  allipoli. But the Gothas that attacked Folkestone in 1917 began the first effective and sustained campaign of strategic civilian bombardment…

• they had developed a ten-pound incendiary bomb of almost pure magnesium, the Elektron, that burned a whole source

  oalescing than any amount of explosives alone. By 1918 they had developed a ten-pound incendiary bomb of almost pure magnesium, the Elektron…

• Bela Kun establishes Hungarian Soviet Republic whole source

  my comrades had disappeared.”17 In the summer of 1919, when Lenin’s Hungarian protégé Bela Kun and his Communist and Social Democratic follo…

• that Szilard, despite his Eötvös Prize, “felt that his skill in mathematical operations could not co whole source

  iend of his studying in Berlin noticed as late as 1922 that Szilard, despite his Eötvös Prize, “felt that his skill in mathematical operatio…

• in Berlin, where he was a Privatdozent at the University of Berlin and a confidant and partner in pr whole source

  rticulate intelligence with the purest brass. In 1928, in Berlin, where he was a Privatdozent at the University of Berlin and a confidant an…

• Fermi could write a friend that he had reached the point of teaching his Pisa teachers: “In the phys whole source

  dicted he would become an important scientist. By 1920 Fermi could write a friend that he had reached the point of teaching his Pisa teacher…

• when Fermi won a postdoctoral fellowship to travel to Göttingen to study under Max Born. whole source

  ption to his rapid progress came in the winter of 1923, when Fermi won a postdoctoral fellowship to travel to Göttingen to study under Max B…

• he had not accomplished any nuclear physics of note except within the well-equipped laboratory of hi whole source

  o invitation to the Solvay Conference. By October 1933 he had not accomplished any nuclear physics of note except within the well-equipped l…

• Oppenheimer went off to Cambridge to attack the center where he could. whole source

  th Paul Horgan and old friends from the summer of 1921, Oppenheimer went off to Cambridge to attack the center where he could. J. J. Thomson…

• the director of the university physics institute, an exceptional physicist and a Senator of the King whole source

  volatile man, forty-six when Fermi sought him out in 1921, the director of the university physics institute, an exceptional physicist and a…

• when he was twenty-five years old, Fermi was chosen under the Italian system of concorsos, national whole source

  as easier to go along with them than against. In 1926, when he was twenty-five years old, Fermi was chosen under the Italian system of conco…

• Szilard waited until the end of December, heard nothing and advanced further into the field. whole source

  tters; Briggs thought the Army ought to handle it.1921 Szilard waited until the end of December, heard nothing and advanced further into the…

• The patent could be registered in his name alone or jointly with Fermi; he would be willing “to assi whole source

  rnment support for this research was forthcoming.”1922 The patent could be registered in his name alone or jointly with Fermi; he would be w…

• Before Washington could respond Szilard had to fight off a harassing attack from the flank. whole source

  is thus one of real importance to our Government.”1924 Before Washington could respond Szilard had to fight off a harassing attack from the…

• Bohr explains atomic basis of the periodic table whole source

  haracterized his scientific work as well.”432 In 1922, the year his Nobel Prize made him a Danish national hero, Bohr accomplished a second…

• that element 72 when discovered would not be a rare earth, as chemists expected and as elements 57 t whole source

  ming the miracle, Bohr predicted in the autumn of 1922 that element 72 when discovered would not be a rare earth, as chemists expected and a…

• Assassination of Walther Rathenau whole source

  pokesman for Jewish causes. In Berlin on June 24, 1922, right-wing extremists gunned down Walther Rathenau, the Weimar Republic’s first Fore…

• what Einstein had postulated in 1905 in his theory of the photoelectric effect: that light was wave whole source

  ot have changed; Compton had in fact demonstrated in 1923 what Einstein had postulated in 1905 in his theory of the photoelectric effect: th…

• In 1940 Lawrence had recruited a Harvard experimentalist named Kenneth Bainbridg whole source

  roblem. Confinement lasted less than a month. In 1940 Lawrence had recruited a Harvard experimentalist named Kenneth Bainbridge, by trade a…

• it met again in Cambridge to hear from other Uranium Committee members and from Bainbridge. whole source

  s’ associates in Washington. A week later, May 5, 1941, it met again in Cambridge to hear from other Uranium Committee members and from Bain…

• and 1934 he applied to the German patent office individually or jointly with his partner Albert Eins whole source

  sidelines, then and later, was invention. Between 1924 and 1934 he applied to the German patent office individually or jointly with his part…

• Schrodinger publishes wave theory of matter whole source

  waves but of particles. Turning the tables, early in 1926 an articulate, cultured Viennese theoretical physicist named Erwin Schrödinger pub…

• in a paper on atomic structure, he was a little less confident. whole source

  “We are living in the heroic age of physics!” By 1927, in a paper on atomic structure, he was a little less confident.575 “We are not yet ab…

• a German physicist, Walther Bothe, “a real physicist’s physicist” to Emilio Segrè, and Bothe’s stude whole source

  isotope its characteristic half-life.580 Around 1928 a German physicist, Walther Bothe, “a real physicist’s physicist” to Emilio Segrè, and…

• the two men had wondered if nuclear transformations of the sort Rutherford was producing at the Cave whole source

  On a walking tour near Göttingen in the summer of 1927 the two men had wondered if nuclear transformations of the sort Rutherford was produc…

• After the summer of 1941 the German bomb program depended entirely on uranium an whole source

  sotope separation in Germany. After the summer of 1941 the German bomb program depended entirely on uranium and Vemork heavy water. * * * Th…

• four months before Oppenheimer arrived. whole source

  The essential vision came to him in the spring of 1929, four months before Oppenheimer arrived. “In his early bachelor days at Berkeley,” wr…

• from another holiday at the Sangre de Cristos ranch with Frank—the ranch was named Perro Caliente no whole source

  in a battered gray Chrysler in the late summer of 1929 from another holiday at the Sangre de Cristos ranch with Frank—the ranch was named Pe…

• on a trip to Antwerp to visit his uncle; thereafter the physicist and the sovereign maintained a reg whole source

  ueen of Belgium. Einstein had met Queen Elizabeth in 1929 on a trip to Antwerp to visit his uncle; thereafter the physicist and the sovereig…

• to organize a group of acquaintances, most of them young physicists, to begin the work of banding to whole source

  urst of optimism—or opportunism—energized Szilard in 1930 to organize a group of acquaintances, most of them young physicists, to begin the…

• Chadwick announces discovery of the neutron whole source

  w approaches to world salvation. On February 27, 1932, in a letter to the British journal Nature, physicist James Chadwick of the Cavendish…

• was the sole certain component of the atomic nucleus, had no electric charge, which meant it could p whole source

  mass as the positively charged proton that until 1932 was the sole certain component of the atomic nucleus, had no electric charge, which me…

• and named for the Greek god of the underworld, a god of the earth’s fertility but also the god of th whole source

  the ninth planet outward from the sun, discovered in 1930 and named for the Greek god of the underworld, a god of the earth’s fertility but…

• Not until 1942 would they officially propose a name for the new element that fis whole source

  Not until 1942 would they officially propose a name for the new element that fissioned like U235 but could be chemically separated from uran…

• had purified a volume of the element almost ten times more intense than any other existing source. whole source

  emical techniques for separating polonium, and by 1931 had purified a volume of the element almost ten times more intense than any other exi…

• beyond recapitulation to discovery: he found, says Chadwick, “that the radiation from beryllium whic whole source

  progressed in the meantime, by the late spring of 1931, beyond recapitulation to discovery: he found, says Chadwick, “that the radiation fro…

• Joliot-Curies report protons from beryllium radiation whole source

  ught seriously about the neutron. On January 18, 1932, the Joliot-Curies reported to the Academy of Sciences their discovery that paraffin w…

• “the prehistory of nuclear physics, and from 1932 on the history of nuclear physics. whole source

  nce remarked that he considered everything before 1932 “the prehistory of nuclear physics, and from 1932 on the history of nuclear physics.”…

• Einstein renounces German citizenship whole source

  to Paris by diplomatic pouch. At the end of March 1933 the most original physicist of the twentieth century once again renounced his German…

• was George Gamow’s ticket of escape from a Soviet Union rapidly becoming inhospitable to theoretical whole source

  lvay Conference, held in Brussels in late October 1933, was George Gamow’s ticket of escape from a Soviet Union rapidly becoming inhospitabl…

• Joliot-Curies win Nobel Prize in Chemistry whole source

  mal accumulation of silicon. Joliot explained why in 1935, when he and his wife accepted the Nobel Prize in Chemistry for their discovery: “…

• while Beveridge and Szilard were still laying plans. whole source

  lready begun paying out its first grant on May 1, 1933, while Beveridge and Szilard were still laying plans. It was an ICI grant that Szilar…

• in the midst of other projects, Amaldi set to work looking for alpha-emitting reactions in uranium i whole source

  to sort everything out. In January and February 1935, in the midst of other projects, Amaldi set to work looking for alpha-emitting reaction…

• alpha, beta and gamma radiation were the only reaction products anyone knew. whole source

  might also screen out other reaction products. In 1935, alpha, beta and gamma radiation were the only reaction products anyone knew. “The ex…

• in the wake of Fermi’s June Nature article “Possible production of elements of atomic number higher whole source

  is now quite attractive.”864 * * * In September 1934, in the wake of Fermi’s June Nature article “Possible production of elements of atomic…

• makes the assumption explicit: “It is reasonable to assume that the atomic number of the active elem whole source

  nd Segrè had delivered to Rutherford in midsummer 1934 makes the assumption explicit: “It is reasonable to assume that the atomic number of…

• paper had to close with many issues not cleared up,” writes the American theoretical physicist John whole source

  d exchanges that Fermi’s work had revealed. “This 1937 paper had to close with many issues not cleared up,” writes the American theoretical…

• Meitner and Hahn renew uranium neutron work whole source

  m. After the war she did physics separately until 1934, when, challenged by Fermi’s work, she “persuaded Otto Hahn to renew our direct colla…

• a young German chemist named Fritz Strassmann, worked to sort out all the substances into which the whole source

  plexities of uranium. She and Hahn, and beginning in 1935 a young German chemist named Fritz Strassmann, worked to sort out all the substanc…

• the Austrian physicist had earned wide respect by hard and careful work. whole source

  his wish I have been granted.”873 Sixty years old in 1938, the Austrian physicist had earned wide respect by hard and careful work. When Wol…

• he had arranged for Brasch and his colleagues in Berlin to break up beryllium with hard X rays; the whole source

  king at St. Bart’s with Chalmers in the summer of 1934 he had arranged for Brasch and his colleagues in Berlin to break up beryllium with ha…

• hydrogen was more efficient than any other element at slowing down neutrons, and slow neutrons avoid whole source

  moderator. As Fermi’s team had discovered in Rome in 1934, hydrogen was more efficient than any other element at slowing down neutrons, and…

• to discuss “the question whether or not the liberation of nuclear energy . whole source

  Port Salut, Szilard turned in the early summer of 1935 to discuss “the question whether or not the liberation of nuclear energy . . . can be…

• he intervened on Szilard’s behalf with the Admiralty, Churchill’s old bailiwick, writing the head of whole source

  ction by the Army in 1915. The following February 1936, he intervened on Szilard’s behalf with the Admiralty, Churchill’s old bailiwick, wri…

• Dempster detects the isotope uranium-235 whole source

  hrough his mass spectrograph at the Cavendish. In 1935, using a more powerful instrument, physicist Arthur Jeffrey Dempster of the Universit…

• Szilard had consistently agreed verbally to that restriction and just as consistently refused as a m whole source

  lating to the project to any unauthorized person.”1935 Szilard had consistently agreed verbally to that restriction and just as consistently…

• But he was willing to meet with Szilard if that was what the physicist wanted. whole source

  opriate sphere of activity in this whole project.”1937 But he was willing to meet with Szilard if that was what the physicist wanted. In Feb…

• But Leo Szilard at least was not yet done with protest. whole source

  es in Eckhart Hall. At present the lights are out.1940 But Leo Szilard at least was not yet done with protest. * * * Enrico Fermi took the i…

• development that physicists throughout the world pursued in all innocence of any intention of findin whole source

  o. Given the development of nuclear physics up to 1938, development that physicists throughout the world pursued in all innocence of any int…

• her article was gathering dust on back shelves, but Bohr had promulgated the liquid-drop model of th whole source

  sics was avant garde, her chemistry was sound. By 1938 her article was gathering dust on back shelves, but Bohr had promulgated the liquid-d…

• and 1939 he noticed and tracked the discovery of nuclear fission. whole source

  elated to his field; in the course of his reading in 1938 and 1939 he noticed and tracked the discovery of nuclear fission.1286 In April 194…

• that they had observed rare spontaneous fissioning in uranium. whole source

  Kurchatov reported to the Physical Review in June 1940 that they had observed rare spontaneous fissioning in uranium. “The complete lack of…

• and early 1940, the nuclear arms race began. whole source

  n might also conceive—and keep secret. That early in 1939 and early 1940, the nuclear arms race began. Responsible men who properly and unde…

• while Fermi and Szilard waited for the $6,000 the Briggs Uranium Committee had allocated to them for whole source

  nclusions to the German War Office on December 6, 1939, while Fermi and Szilard waited for the $6,000 the Briggs Uranium Committee had alloc…

• it was already clear to two intelligent observers that nuclear weapons would be weapons of mass dest whole source

  th a similar weapon. Thus in the first months of 1940 it was already clear to two intelligent observers that nuclear weapons would be weapon…

• when the news of fission arrived; like Philip Abelson, he was excited by the discovery and chagrined whole source

  He had been practicing it at Berkeley in January 1939 when the news of fission arrived; like Philip Abelson, he was excited by the discovery…

• to announce the news of fission, had moved to the Naval Research Laboratory in 1941 to work on urani whole source

  Alvarez had run from his barber chair in January 1939 to announce the news of fission, had moved to the Naval Research Laboratory in 1941 to…

• was inventing a relatively cheap way to make uranium hexafluoride. whole source

  or K-25. Abelson’s first technical contribution, in 1941, was inventing a relatively cheap way to make uranium hexafluoride. He processed th…

• report, submitted jointly with his NRL colleague Ross Gunn, indicated that uranium could be enriched whole source

  ube started the flow again. Abelson’s January 4, 1943, report, submitted jointly with his NRL colleague Ross Gunn, indicated that uranium co…

• Bohr announces the discovery of fission whole source

  ad been a student at George Washington University in 1939 and had attended the conference there on January 25 at which Niels Bohr announced…

• was 54 percent, an extraordinary density of killing; by contrast, the death rate for the March 9 fir whole source

  0,000. The death rate for deaths up to the end of 1945 was 54 percent, an extraordinary density of killing; by contrast, the death rate for…

• Liebow used a British invention, the Standardized Casualty Rate, to compute that Little Boy produced whole source

  rmy Institute of Pathology in Washington in early 1946 Liebow used a British invention, the Standardized Casualty Rate, to compute that Litt…

• which is difficult to reconcile with Fermi’s proposal to Dunning of a confirming experiment on Jan. whole source

  ermi: but remembers doing so as early as Jan. 17, 1939, which is difficult to reconcile with Fermi’s proposal to Dunning of a confirming exp…

• is the only Sunday between LS’s July 9 letter to Fermi and his post-meeting July 19 letter to AE. whole source

  by Wigner’s secretary on Monday morning; July 16, 1939, is the only Sunday between LS’s July 9 letter to Fermi and his post-meeting July 19…

• Auer orders sixty tons of uranium oxide from Belgium whole source

  y laying in industrial stocks of uranium. In June 1940, about the time Simon was hammering out his kitchen strainer, Auer ordered sixty tons…

• following a conference with his colleagues, he stressed their consensus that isotope separation woul whole source

  When Harteck reported to the War Office in March 1941, following a conference with his colleagues, he stressed their consensus that isotope…

• Imperial Army authorizes Japanese atomic bomb research whole source

  an measuring cross sections in December. In April 1941 the official order came through: the Imperial Army Air Force authorized research towa…

• to begin sorting out its chemistry—although he was a physicist by graduate training, he had earned h whole source

  are-earth fission product. He found time in April 1940 to begin sorting out its chemistry—although he was a physicist by graduate training,…

• the same day Louis Turner sent Szilard his transuranic theories: anticipation and discovery can cut whole source

  ve element 93,” to the Physical Review on May 27, 1940, the same day Louis Turner sent Szilard his transuranic theories: anticipation and di…

• while visiting Berkeley to deliver a lecture, Enrico Fermi attended a seminar one of Oppenheimer’s p whole source

  peared amateurish and snobbish.” Out of curiosity in 1940, while visiting Berkeley to deliver a lecture, Enrico Fermi attended a seminar one…

• that the United States must also be pursuing a program when the names of prominent physicists, chemi whole source

  ready in Nazi Germany. Soviet physicists realized in 1940 that the United States must also be pursuing a program when the names of prominent…

• he heard from George Flerov, one of the two young physicists in his Moscow laboratory who had discov whole source

  nses against naval mines. In Kazan at the end of 1941 he heard from George Flerov, one of the two young physicists in his Moscow laboratory…

• when the element in useful concentrations was thought to be rare, the general, acting on behalf of t whole source

  of millions of tons Groves may not have known. In 1943, when the element in useful concentrations was thought to be rare, the general, actin…

• some 1,200 tons in all, the only source of untraced bomb material available to them during the war w whole source

  Germans had confiscated when they invaded Belgium in 1940, some 1,200 tons in all, the only source of untraced bomb material available to th…

• to install the process equipment into the first completed separation building by remote control, pre whole source

  one hundred of whom arrived at Hanford in October 1944, to install the process equipment into the first completed separation building by rem…

• Germany seizes 1,200 tons of Belgian uranium ore whole source

  George Marshall that closed the German book: In 1940 the German Army in Belgium confiscated and removed to Germany about 1200 tons of uraniu…

• Oak Ridge had produced enough U235 to allow a nearcritical assembly of pure metal without hydride di whole source

  By April 1945 Oak Ridge had produced enough U235 to allow a nearcritical assembly of pure metal without hydride dilution. The little bars ar…

• “this was the first I had heard about even the remote possibility of a bomb. whole source

  division of the NDRC adds that, as late as March 1941, “this was the first I had heard about even the remote possibility of a bomb.” Nor did…

• to determine the man-made element’s various cross sections. whole source

  aborg had continued working through the spring of 1941 to determine the man-made element’s various cross sections. On Sunday, May 18, having…

• In that summer of 1941, with recollections of what I had seen and heard in Engla whole source

  orthy of serious consideration. In that summer of 1941, with recollections of what I had seen and heard in England fresh in my mind, I was i…

• Zhukov counterattacks German army outside Moscow whole source

  t level, was a doubles squash court. December 6, 1941, the day of the bomb program expansion, marked another tidal event: Soviet forces unde…

• to promote atomic bomb research. whole source

  and the Imperial Navy had moved separately since 1941 to promote atomic bomb research.1779 The Riken, Yoshio Nishina’s prestigious Tokyo lab…

• In the spring of 1942 the Navy committed itself to developing nuclear power for whole source

  gnetic and centrifuge processes. In the spring of 1942 the Navy committed itself to developing nuclear power for propulsion: The study of nu…

• when the Navy committee began to report discouragement, he met privately with a young cosmic-ray phy whole source

  onclusions of his own, however, and at the end of 1942, when the Navy committee began to report discouragement, he met privately with a youn…

• and proved it inadequate for separating uranium isotopes, but Nishina had no knowledge of that secre whole source

  n’s liquid thermal diffusion) at Birmingham early in 1941 and proved it inadequate for separating uranium isotopes, but Nishina had no knowl…

• when he reported difficulty producing uranium hexafluoride. whole source

  ith Nobuuji until seven months later, in February 1944, when he reported difficulty producing uranium hexafluoride. His team had managed to…

• But the majority of the whole source

  ttee selected the most promising design on May 1, 1945, but only a full-scale test culminating in a chain reaction could prove definitively…

• [Fromm] remarked that our only chance of winning the war lay in developing a weapon with totally new whole source

  rse of one of these meetings, at the end of April 1942, [Fromm] remarked that our only chance of winning the war lay in developing a weapon…

• Oppenheimer convenes the Berkeley luminaries whole source

  the tiny pinkish speck. * * * In the summer of 1942 Robert Oppenheimer gathered together at Berkeley a small group of theoretical physicists…

• the Cornell physicist had established himself as a theoretician of the first rank. whole source

  t of luminaries Oppenheimer wanted to attract. By 1942 the Cornell physicist had established himself as a theoretician of the first rank. Hi…

• JRO Papers, Box 71: “In connection with these reactions it occurred to me that our Lithium Deuterite whole source

  um deuteride: cf. Teller to Oppenheimer, Sept. 5, 1942, JRO Papers, Box 71: “In connection with these reactions it occurred to me that our L…

• to see if they could find any new reason to believe a pile might serve as a weapon. whole source

  nvened a conference of experts on the last day of 1943 to see if they could find any new reason to believe a pile might serve as a weapon. “…

• and then pressure was put on me by Oppenheimer and General Groves and particularly Conant, which rea whole source

  oing to Los Alamos as a consultant in the Fall of 1943, and then pressure was put on me by Oppenheimer and General Groves and particularly C…

• drawing on several fine collections of classical records, including Oppenheimer’s; the few New Mexic whole source

  broadcasting to Hill residents on Christmas Eve, 1943, drawing on several fine collections of classical records, including Oppenheimer’s; th…

• Oppenheimer traveled via Key Railway from Berkeley to San Francisco on the evening of June 14, 1943, whole source

  ’s peepshow version of that meeting: On June 14, 1943, Oppenheimer traveled via Key Railway from Berkeley to San Francisco on the evening of…

• for a full-scale test of an implosion weapon. whole source

  ad to resist in himself. Planning began in March 1944 for a full-scale test of an implosion weapon. Sometime between March and October Oppen…

• In England in 1943 and 1944 he worked night and day to improve precision bombing whole source

  eadquarters navigator, B-10’s, B-17’s. In England in 1943 and 1944 he worked night and day to improve precision bombing. He won quick promot…

• It was the end of 1944 and he was feeling the pressure of accumulating Manhattan whole source

  et practice for Tibbets’ crews. It was the end of 1944 and he was feeling the pressure of accumulating Manhattan Project delays: “General Gr…

• batches of plutonium nitrate containing gram quantities of plutonium had begun arriving at Los Alamo whole source

  tions began the following month. By the summer of 1944 batches of plutonium nitrate containing gram quantities of plutonium had begun arrivi…

• when she, Enrico Fermi and Crawford Greenewalt climbed giddily to the top of a twelve-story tower to whole source

  lls of a day at Hanford, Washington, in September 1944 when she, Enrico Fermi and Crawford Greenewalt climbed giddily to the top of a twelve…

• Conant says, on an earlier inspection trip to Los Alamos, he and Bush had found leisure and privacy whole source

  interested in improvements. During the summer of 1944, Conant says, on an earlier inspection trip to Los Alamos, he and Bush had found leisu…

• was just beginning to come on line, working with the physics department of the University of New Mex whole source

  ecently he had been test-piloting the B-29, which in 1944 was just beginning to come on line, working with the physics department of the Uni…

• with his assumptions at the beginning of the new year to draw up a problematic balance sheet: while whole source

  . Conant also contrasted his assumptions of June 1944 with his assumptions at the beginning of the new year to draw up a problematic balance…

• Oak Ridge ships bomb-grade U235 to Los Alamos whole source

  ”2243 Perhaps he was simply being prudent. Early in 1945 Oak Ridge began shipping bomb-grade U235 to Los Alamos. Between shipments Groves to…

• reduced Trinity’s priority, says Bainbridge, “almost to zero . whole source

  demands of the implosion crisis in the autumn of 1944 reduced Trinity’s priority, says Bainbridge, “almost to zero . . . until the end of Fe…

• he was greatly worried about the use and consequences of the atomic bomb. whole source

  partially to men and to nations. In the spring of 1945 he was greatly worried about the use and consequences of the atomic bomb. The other m…

• Truman orders the atomic bomb used and picks targets whole source

  isers was one level of discourse in the spring of 1945 on the uses of the atomic bomb. Another was joined two days after Stimson and Groves…

• as Curtis LeMay’s bombers shuttled back and forth burning cities, Colonel Elmer E. whole source

  19 Tongues of Fire At the end of March 1945, as Curtis LeMay’s bombers shuttled back and forth burning cities, Colonel Elmer E. Kirkpatrick,…

• that Groves and Oppenheimer at Trinity were preparing their first report of the tower shot’s success whole source

  ravaged Berlin at about the same time on July 16, 1945, that Groves and Oppenheimer at Trinity were preparing their first report of the towe…

• account of his career, Speaking Frankly, narrates an entire chapter about Potsdam without once menti whole source

  o why should Mr. Stimson be there?” Byrnes in his 1947 account of his career, Speaking Frankly, narrates an entire chapter about Potsdam wit…

• on one of the targets: Hiroshima, Kokura, Niigata and Nagasaki. whole source

  r will permit visual bombing after about 3 August 1945 on one of the targets: Hiroshima, Kokura, Niigata and Nagasaki. . . . 2. Additional b…

• Szilard petitions against using the atomic bomb whole source

  Teller revived a variant rationale in early July 1945, in replying to Szilard about a petition Szilard was then circulating among Manhattan…

• and 140,000 altogether across the next five years, a death rate like Hiroshima’s of 54 percent. whole source

  e Boy. But 70,000 died in Nagasaki by the end of 1945 and 140,000 altogether across the next five years, a death rate like Hiroshima’s of 54…

• President Harry Truman welcomed the bomb as a substitute for Soviet entry into the Pacific war. whole source

  mas Power. 98. At the Potsdam Conference in July 1945 President Harry Truman welcomed the bomb as a substitute for Soviet entry into the Pac…

• quoted in Weart and Szilard (1978), p. whole source

  s] . . . is pessimistic”: New York Post, Nov. 24, 1945, quoted in Weart and Szilard (1978), p. 3n. 399. “a society . . . achievement”: Smith…

• Szilard Papers: “Only a man with [Szilard’s] brass would have pushed through to the President. whole source

  m: cf. transcript of Groves interview of March 8, 1946, Szilard Papers: “Only a man with [Szilard’s] brass would have pushed through to the…

• memoir he recalled several: We feared that, if the Japanese were told that the bomb would be used o whole source

  icant responses to the question are Byrnes’. In a 1947 memoir he recalled several: We feared that, if the Japanese were told that the bomb w…

• He was concerned particularly about German heavy-water production because British scientists believe whole source

  h at the Cosmos Club in Washington in August 1943.1948 He was concerned particularly about German heavy-water production because British sci…

• Bohr reported a more specific commitment from the President: he “left with Professor Bohr the impres whole source

  lasted an hour and a half. To Robert Oppenheimer in 1948 Bohr reported a more specific commitment from the President: he “left with Professo…

• Oppenheimer recalled an odd group delusion: Very shortly before the test of the first atomic bomb, whole source

  vities of life.” In a letter to Eleanor Roosevelt in 1950 Oppenheimer recalled an odd group delusion: Very shortly before the test of the fi…

• Hanford operators trained and deployed whole source

  he required his operators, one hundred of whom arrived at Hanford in October 1944, to install the process equipment

• Hanford begins plutonium separation whole source

  B-pile slugs traveled by rail into the 221-T separation plant beginning on December 26, 1944

• Hanford plutonium yields reach 90 percent whole source

  reached 90 per cent early in February 1945

• ALSOS mission enters liberated Paris whole source

  The ALSOS Mission then entered the City of Paris 0855 hrs., 25 August 1944. The party proceeded to within the city in the rear of the first…

• ALSOS finds Germany has no atomic bomb program whole source

  The conclusions were unmistakable. The evidence at hand proved definitely that Germany had no atom bomb and was not likely to have one in an…

• Stimson bars Kyoto from atomic bomb targets whole source

  So Kyoto at least, the Rome of Japan, founded in 793, famous for silk and cloisonné, a center of the Buddhist and Shinto religions with hund…

• Joint Chiefs order Operation Olympic invasion of Kyushu whole source

  The Joint Chiefs of Staff direct the invasion of Kyushu (operation OLYMPIC) target date 1 November 1945

• Interim Committee meets with the Scientific Panel whole source

  The Interim Committee was to meet in full dress with its Scientific Panel on Thursday, May 31, and on Friday, June 1, with its industrial ad…

• Enola Gay loaded with the Little Boy bomb whole source

  The colonel began by saying that whatever any of us, including himself, had done before was small potatoes compared to what we were going to…

• Enola Gay takes off for Hiroshima whole source

  He eased the brakes at 0245, the four fuel-injected Wright Cyclone engines pounding

• Atomic bombing of Hiroshima whole source

  At the same instant birds ignited in midair. Mosquitoes and flies, squirrels, family pets crackled and were gone. The fireball flashed an en…

• General LeMay confirms Hiroshima bombing mission for August 6 whole source

  General LeMay officially confirmed that the mission would take place on August 6

• Truman authorizes atomic bombing of Japan whole source

  Fat Man dropped from the B-29, fell through the hole and exploded 1,650 feet above the steep slopes of the city at 11:02 A.M., August 9, 194…

• Bock's Car departs Tinian for Nagasaki whole source

  The night of our takeoff was one of tropical rain squalls, and flashes of lightning stabbed into the darkness with disconcerting regularity