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FDR and the bomb

Friday, September 30th, 2016

Franklin D. Roosevelt is one of the most enigmatic figures of the early American atomic bomb program. The four-term US president always features briefly in any story of the Manhattan Project: first, for his creation of the Advisory Committee on Uranium, an exploratory research effort in response to a letter urging government action that was sent by Albert Einstein in August 1939; second, for his approval of a broader expansion of that research into a “pilot” program in late 1941, just before the US entry into World War II, which resulted in more intensive investment into uranium enrichment and reactor design; and third, in mid-1942, Roosevelt approved bringing in the US Army Corps of Engineers to manage a full-scale bomb-production project. This latter action is often subsumed by the attention given the first two, but it is the production program decision that actually resulted in the US getting an atomic bomb by 1945, and is the decision that makes the United States unique among powers in the Second World War, as while several powers had research programs, only the US turned it into a production program. It was the beginning of the Manhattan Project as we tend to characterize it, the kind of program that produces weapons and not just data.

A little history trick I always tell my students: if you see Truman and FDR in the same photograph, that means Truman doesn't know about the atomic bomb. Photo source: History.com

A little history trick I always tell my students: if you see Truman and FDR in the same photograph, that means Truman doesn’t know about the atomic bomb. Photo source: History.com

So Roosevelt looms large, as he ought to. Without Roosevelt’s actions, there would have been no atomic bomb in World War II. And yet… What did FDR really think about the atomic bomb? Did he see it as a true end-the-war weapon? Did he think it was meant to be used in war (as a first-strike weapon) or did he think of it primarily as a deterrent (i.e., against the Germans)? The question isn’t just an idle one, because Roosevelt’s sudden death, on April 12, 1945, left his successor, Harry Truman, with major decisions to make about the future of the war, and Truman, in part, thought he was acting in accordance with FDR’s wishes on this matter. But, as is well known, FDR never told Truman about the atomic bomb work, and never set out his wishes on this matter — so there was a tremendous amount of assumption involved.

I get asked about FDR’s views on a fairly regular basis, and it’s one of those wonderful questions that seems simple but is really quite complex, and quickly gets you into what I think of as “epistemological territory”: How do we know what someone’s views were, in the past? How do we get inside the head of someone dead? Well, you might say, obviously we can’t completely get inside someone’s head (we can barely get inside the heads of people who are alive and in front of us, and a Freudian might argue that we barely have conscious access to our own motivations and thoughts), but we can look at what evidence there is that was written down that might reveal some of their inner thoughts.

But with FDR, this is very tricky: he didn’t write that much down. He didn’t keep a diary or journal. He didn’t send that many letters. He didn’t record phone calls, conversations, write “memos to self,” or any of the other documenting habits that are common to major political figures. He was notoriously secretive and private. He didn’t explain himself. If Truman was comparatively straightforward in his thinking and action, Roosevelt was a grand schemer, trying to out-wit and out-charm the world (sometimes successfully, sometimes not). He could be downright gnomic. At one point, Vannevar Bush (FDR’s top science advisor) asked Roosevelt whether the Secretary of the Navy ought to be included in discussions on the bomb project. He later recalled that FDR “looked at me with one of his strange smiles and said, ‘No, I guess not, not now.'” End of anecdote, no real indication as to what FDR was thinking, other than a “strange smile” that no doubt concealed much.1

What approval of a nuclear weapons program looked like under Roosevelt: "VB OK FDR." Report by Vannevar Bush of June 16, 1942, asking to expand the fission work into an all-out effort.

What approval of a nuclear weapons program looked like under Roosevelt: “VB OK FDR.” Report by Vannevar Bush of June 16, 1942, asking to expand the fission work into an all-out effort.

As this example indicates, we do sometimes have accounts, including contemporary ones, by people who met with Roosevelt and talked with him. But even these can be quite tricky, because FDR did not, again, generally explain his full thinking. So people like Bush were left with half-versions of the story, knowing what FDR said but not what he thought, and while this is, to be sure, a common-enough human experience, with FDR the gap between thought and expression was exceptionally large.

Separately, there is another, related issue that complicates our understanding: people who met with FDR would often use tales of his agreement as a form of authority. Vannevar Bush did this repeatedly, and this is no doubt a pretty standard mode of operation regarding advisors and presidents. Bush would go to FDR with an idea, convince FDR to sign off on Bush’s idea, and then claim it was FDR’s idea, because while people might feel free to disagree with Bush, they couldn’t really disagree with FDR. One of the most famous examples of this is Bush’s report on postwar American science policy, Science—The Endless Frontier, which is constructed to look like it is a reply to a letter by FDR for guidance, but was entirely engineered by Bush as a means of pushing his own agenda, with FDR being a complicit as opposed to a driving force.2

So what do we know? The number of documents that give insight into FDR’s personal thoughts about the atomic bomb — what it was, what it could be used for, what his plans were — are very slim. Some of this is a function of timing: FDR died right around when they were getting concrete estimates for when the atomic bomb would be ready to use, and had he lived until, say, May 1945, he might have been faced with more direct questions about his plans for it. (The first Target Committee meeting was on April 27, and the Interim Committee was created in early May, just to give an indication of how things rapidly started to come together right after FDR died.) So he wasn’t part of the conversations that directly led to the use of the atomic bombs on Japanese cities.

But there are a few other documents that are useful in assessing FDR’s views. It seems fairly clear that FDR’s approval of the Uranium Committee in 1939 was initially because he was interested in the deterrent quality of the bomb. Alexander Sachs, who had the meeting with Roosevelt, related that FDR had confirmed that the goal was “to see that the Nazis don’t blow us up.”3 Again, this wasn’t yet a bomb-making program, it was just a “see if bombs are worth worrying about” program, but that’s still a little insight: it shows, perhaps, that the initial, explicit attraction was not in making a new wonder-weapon, but deterring against another one.

Roosevelt, Truman, and FDR's previous VP, Henry Wallace. Truman is the only one here who doesn't know about the bomb program. Image source: Truman Library via Wikimedia Commons

Roosevelt, Truman, and FDR’s previous VP, Henry Wallace. Truman is the only one here who doesn’t know about the bomb program. Image source: Truman Library via Wikimedia Commons

Between 1939 and 1941 there are big gaps in anything that would indicate FDR’s views on the bomb. This is not surprising, because this was a period of relative lack of movement in the US fission program, which was not yet a bomb program. FDR was occasionally involved in discussions about the program, but there was no “bomb” yet to worry about one way or the other. In late 1941, FDR approved accelerating and expanding the research, at the urging of Bush, James Conant, Ernest Lawrence, and Arthur Compton, and in mid-1942 he approved of a full bomb production program, as previously noted. None of these documents indicate intent for use, however. The June 1942 report by Vannevar Bush and James Conant, whose approval by Roosevelt is indicated only by a scrawled “VB OK FDR” on its cover letter, indicates that a weapon made with 5-10 kilograms of U-235 or Pu-239 (then just called “Element 94”) would have an explosive power of “several thousand tons of TNT.” It goes into great detail on the types of plants to be constructed and the organization of the research. It predicts a “bomb” would be ready by early 1944. But at no point does it indicate what the point of such a weapon was: as a deterrent, as a first-strike weapon, as a demonstration device, etc. There is only point, towards the end, which suggests that a committee be eventually formed to consider “the military uses of the material,” but even this is primarily concerned with research and development for the plants. This is not to say that Bush, Conant, et al. did not have their views on whether it would be a weapon to use or not — but the report does not indicate any such views, and so FDR’s endorsement of it doesn’t tell us much.4

Bush met with Roosevelt many times during the war, and sometimes would write down, afterwards, what they talked about. Clearly this is FDR-as-filtered-through-Bush, but we’ll take what we can get. In late June 1943, Bush wrote to Conant with an account of a recent meeting he had with FDR on “S-1,” their code for the bomb work. In it, Bush related that FDR was curious about the progress of the work and the schedule for having a bomb. Bush told him things were going well but still tentative, and that the date of a bomb had been pushed back to early January 1945, but that this could shift in either direction. FDR also wanted to know how the Germans were doing. Bush explained that they didn’t really know, that they were trying to find ways to slow down any German work, and that they were still worried about being behind the Germans. (They would eventually come to understand they had surpassed them.) Then there is this really interesting passage which is worth quoting from the original:

He [FDR] then himself discussed what the enemy attitude of mind would be if they felt they had this coming along, and were inclined to remain on the defensive until it could eventuate. We then spoke briefly of the possible use against Japan, or the Japanese fleet, and I brought out, or I tried to, that because at this point I do not think I was really successful in getting the idea across, that our point of view or our emphasis on the program would shift if we had in mind use against Japan as compared with use against Germany.5

After which the conversation then shifted to other matters. Such a tantalizing snippet of discussion, but not as fleshed out as one might want! What did Bush and FDR understand the difference to be between the Japanese versus the Germans? Who initially brought up the possibility of use against the Japanese? What did FDR think about the German “attitude of mind”? This snippet hints at exactly the topics one might care about but doesn’t actually reveal anything about FDR’s views on them! Impressively frustrating!

Most of FDR’s interactions with Bush, Groves, and others during this period concerned diplomatic issues, specifically cooperation with the British (a rather long, drawn-out saga), and even a meeting with Niels Bohr (from which FDR mostly took away a fear that Bohr might alert the Soviets, or others, to the US work). FDR helped, for example, in helping to shut down unionization activities at the Berkeley Radiation Laboratory, and was kept abreast of efforts made to monopolize global uranium ore resources. He was not “checked out” in any respect; he was dramatically more concerned with the ins-and-outs of the fission work than, say, Truman would later be. But again, very little of this left any record about what he thought they were going to do with the bomb.6

Atomic diplomacy: Roosevelt and Churchill at Quebec, in September 1944. Source: NARA via Wikimedia Commons

Atomic diplomacy: Roosevelt and Churchill at Quebec, in September 1944. Source: NARA via Wikimedia Commons

Two of the only documents that reveal any FDR-specific thoughts about the use of the bomb were agreements he made with Winston Churchill. In August 1943, Churchill and Roosevelt met in Quebec, Canada, and hammered out the secret “Quebec Agreement.” It said, among other matters, that the US and UK would pool their efforts at both making the bomb and securing global uranium reserves, that they would never nuke each other, that they would never nuke anyone else without mutual agreement, and they would not reveal the secrets of the bombs without mutual agreement. So this at least provides a framework for using the bomb, but it is a limited one — FDR was willing to deliberately tie the US’s hands with regards to dropping of the atomic bomb to the approval of a foreign power, quite an amazing concession!7

Another meeting between Roosevelt and Churchill, in Hyde Park, New York, produced yet another fascinating agreement. The Hyde Park Aide-Mémoire of September 1944 contained the following clause:

The suggestion that the world should be informed regarding tube alloys, with a view to an international agreement regarding its control and use, is not accepted. The matter should continue to be regarded as of the utmost secrecy; but when a “bomb” is finally available, it might perhaps, after mature consideration, be used against the Japanese, who should be warned that this bombardment will be repeated until they surrender.

Here they were explicitly rejecting the appeal by Niels Bohr (which he was able to make personally to both FDR and Churchill, on separate occasions) to alert the world about the atomic bomb. But it is of interest that they were, at this point, specifically thinking about using the bomb against the Japanese (not Germany), but that they thought it would require “mature consideration” before use, and that they were putting “bomb” in scare-quotes. This is one of the few indications we have of FDR’s awareness and acceptance of the idea that the bomb might be used as a first-strike weapon, and against the Japanese in particular.

Lastly, there is one other significant FDR-specific datapoint, which I have written about at length before. In late December 1944, with Yalta looming, Roosevelt and Groves met in the Oval Office (along with Henry Stimson, the Secretary of War). In Groves’ much later recollection (so we can make of that what we will), Roosevelt asked if the atomic bomb might be ready to use against Germany very soon. Groves explained that for a variety of reasons, the most important one being that their schedule had pushed the bomb back to the summer of 1945, this would not be possible. It is an interesting piece, one that simultaneously reveals Roosevelt’s potential willingness to use the atomic bomb as a first-strike weapon, his willingness to use it against Germany specifically, and the fact that FDR was sufficiently out of the loop on planning discussions to not know that this would both be impossible and very difficult. In other words, it reveals that FDR wasn’t aware that by that point, it was expected that the bomb could only be used against Japan, and that is a rather large thing for him not to know — further evidence, perhaps, that he was not completely abreast of these kinds of discussions. At the meeting, Groves gave FDR a report that predicted a weapon ready for use in early August 1945, and specified that it was time to begin military planning, which Groves annotated as having been “approved” by the Secretary of War and the President. But there doesn’t seem to have been any specifics of targets, or even targeting philosophy, agreed upon at this point.8

What can we make of all this? Frequently I have seen people take the position that Truman himself took: assuming that Roosevelt would have used the bomb in the way that Truman did, because what else might he have been planning? I would only caution that there were more “options” on the table even for Truman than we tend to talk about, which is just another way to say that dropping two atomic bombs in rapid succession on cities is not the only way to use an atomic bomb even militarily. That is, even if one thinks it was inevitable that the bombs would be used in a military fashion (which I think is probably true), it is unclear what position FDR might have taken on the question of specific targets (e.g., the Kyoto question), the question of timing (e.g., before or after the Soviet invasion; how many days between each strike?), and diplomatic matters (e.g., would Roosevelt be more open to modifying the Potsdam Declaration terms than Truman was?). So there is room for considerable variability in the “what if Roosevelt hadn’t died when he did?” question, especially given that Roosevelt, unlike Truman, had been following the bomb work from the start, and was as a result much less reliant on his advisors’ views than Truman was (he frequently bucked Bush, for example, when it came to matters relating to the British).

Would Roosevelt have dropped the bomb on Japan, had he not died? I suspect the answer is yes. One can see, in these brief data points, a mind warming up to the idea of the atomic bomb as not just a deterrent, but a weapon, one that might be deployed as a first-strike attack. In some ways, FDR’s query to Groves about Germany is the most interesting piece: this was a step further than anyone else at the time was really making, since Germany’s defeat seemed inevitable at that point. But, again, the strict answer is, of course, that we can’t really know for sure. Perhaps if FDR had confided his inner thoughts on the bomb to more people, perhaps if he had written them down, perhaps if he had been more involved in the early targeting questions, then we would be able to say something with more confidence. Unless some new source emerges, I suspect Roosevelt’s thoughts on the bomb will always have something of an enigma to them. It is not too far-fetched to suggest that this may have always been his intention.

Notes
  1. Vannevar Bush, Pieces of the action (New York: Morrow, 1970), 134. []
  2. See Daniel J. Kevles, “The National Science Foundation and the Debate over Postwar Research Policy, 1942-1945: A Political Interpretation of Science–The Endless Frontier,” Isis 68, no. 1 (1977), 4-26. Another example of this behavior, from my own research, is when Bush wanted to seize patent rights relating to atomic research during the war — this was an idea cooked up by Bush, approved by FDR, and then presented as an idea of FDR’s, to give it more political, legal, and moral heft. See Alex Wellerstein, “Patenting the Bomb: Nuclear Weapons, Intellectual Property, and Technological Control,” Isis 99, no. 1 (2008), 57-87, esp. 65-66. []
  3. Quoted in Richard Rhodes, The Making of the Atomic Bomb (Simon and Schuster, 1986), on 314. []
  4. Vannevar Bush and James Conant, “Atomic Fission Bombs,” (17 June 1942), with attached cover letter initialed by Roosevelt, copy in Harrison-Bundy Files Relating to the Development of the Atomic Bomb, 1942-1946, microfilm publication M1108 (Washington, D.C.: National Archives and Records Administration, 1980), Folder 58: “Vannevar Bush Report – March 1942,” Roll 4, Target 4. []
  5. Vannevar Bush to James Conant, “Memorandum of Conference with the President,” (24 June 1943), copy in Bush-Conant File Relating the Development of the Atomic Bomb, 1940-1945, Records of the Office of Scientific Research and Development, RG 227, microfilm publication M1392, National Archives and Records Administration, Washington, D.C., n.d. (ca. 1990), Roll 2, Target 5, Folder 10, “S-1 British Relations Prior to the Interim Committee [Fldr.] No. 2 [1943, some 1944, 1945].” []
  6. For a very nice discussion of Roosevelt’s wartime “atomic diplomacy,” see Campbell Craig and Sergey Radchenko, The atomic bomb and the origins of the Cold War (Yale University Press, 2008), chapter 1, “Franklin Delano Roosevelt and Atomic Wartime Diplomacy,” 1-33. On the UK-US atomic alliances, see Barton Bernstein, “The uneasy alliance: Roosevelt, Churchill, and the atomic bomb, 1940-1945,” Western Political Quarterly 29, no. 2 (1976), 202-230 []
  7. And just to follow up on that: the US did, in the summer of 1945, request formal UK approval for the dropping of the atomic bomb, and for the release of the Smyth Report and other publicity. The UK readily gave assent to using the weapon against the Japanese, but they did question the wisdom of releasing the Smyth Report. They eventually consented to that as well, after stating their reservations. []
  8. Just as an aside: the meeting, by Stimson’s diary account, was only 15 minutes long, and most of it pertained to questions of diplomacy (specifically potential British violations of the Quebec Agreement with respect to French patent arrangements). Stimson’s diary entry mentions nothing about targeting question, German, Japanese, or otherwise. So either the discussion of Germany and Japan did not make much impression on him, or he did not think it prudent to write it down. See Henry Stimson diary entry for December 30, 1944, Yale University. Groves own contemporary record of the meeting also neglects to mention anything relating to targets, and instead is entirely focused on diplomatic questions. Leslie Groves, Memorandum on Meeting with President (30 December 1944), Correspondence (“Top Secret”) of the Manhattan Engineer District, 1942-1946, microfilm publication M1109 (Washington, D.C.: National Archives and Records Administration, 1980), Roll 3, Target 7, Folder 24, “Memorandums to (Gen.) L. R. Groves Covering Two Meetings with the President (Dec. 30, 1944, and Apr. 25, 1945).” []
Visions

Historical thoughts on Michael Frayn’s Copenhagen

Friday, February 26th, 2016

When I meet new, educated-but-not-academic people for the first time, and the subject of what I study for a living comes up, I almost invariably get two questions. The first is almost always some variant on the question of whether Hiroshima and Nagasaki were necessary. The second is almost always about Werner Heisenberg.

Werner Heisenberg (at right) with Niels Bohr (center) and Elisabeth Heisenberg (left), 1937. (Victor Weisskopf makes a cameo appearance on the left, in the back.) Source: Emilio Segrè Visual Archive, American Institute of Physics.

Werner Heisenberg (at right) with Niels Bohr (center) and Elisabeth Heisenberg (left), 1937. (Victor Weisskopf makes a cameo appearance on the left, in the back.) Source: Emilio Segrè Visual Archive, American Institute of Physics.

Did Heisenberg try to sabotage the German bomb project? Does the failure of the Germans to produce a bomb during World War II reflect on Heisenberg’s technical knowledge, his moral choices, or Allied sabotage? What do historians think, in the end, that Heisenberg was trying to do when he visited his mentor Niels Bohr in occupied Copenhagen in the fall of 1941?

These questions, often without saying so explicitly, tend to stem from one source these days: Michael Frayn’s Tony Award-winning play Copenhagen, first performed in 1998 but often re-performed, and having also been turned into a PBS film in 2002.

This pair of questions, as a pair of cities (Hiroshima and Copenhagen), is interesting to me as a historian. These appear to be the touchstone of American intellectuals’ knowledge of nuclear history, broadly speaking. One rooted in a controversial act of war, the other in a controversial piece of theatre. It is, perhaps, more of a testament to the theatre to get people (at least some people) thinking about history than one might typically suspect — that Americans think about Hiroshima is perhaps as it ought to be, that they think about Copenhagen is far more curious.

Michael Frayn's Copenhagen

When I was an undergraduate majoring in the history of science at UC Berkeley in the early 2000s, Copenhagen was very much in the air. It had just come to America (I saw the San Francisco production twice), and it resulted in the early release, in 2002, of several sealed letters in the Niels Bohr Archive relating to Niels Bohr and Werner Heisenberg’s 1941 meeting. My undergraduate advisor was a Heisenberg scholar, and I took several classes with her that touched very directly on the history of the American and German bomb projects. One of my last acts at Berkeley was to design the cover for an excellent volume of historical essays on the play. So the play has had a remarkably large role in my early interest in nuclear history.

Last fall I was asked to take part in a Q&A about the play at the Central Square Theatre in Cambridge with Alan Brody of MIT, where it was showing. Aside from giving me a chance to visit my old grad school stomping grounds (the first time, I think, since I started my current job), it also gave me a fresh excuse to revisit the play, about a decade after I last spent any real time thinking about it. What follows is based on what I said at the panel.

What did Heisenberg and Bohr talk about in 1941? I think the main response from historians that you are likely to get is: we’ll never know, and it probably isn’t that important in the scheme of things anyways. Which is to say, not much of an answer. All we have to go on regarding that conversation are a few later recollections from the only two people who were there — Bohr and Heisenberg — and all of those recollections have been fairly “tainted” by quite a lot of other events that came afterwards, and do not match up with each other. What I mean by “tainted” is that there became high stakes for both sides for remembering the events in different ways, and the effects of the successful Allied atomic bombs, coupled with the full revelation of the crimes of Nazi Germany, makes it hard for anyone to be anything like objective after the fact.

Niels and Margrethe Bohr, on the motorcycle of George Gamow, 1930. Source: Emilio Segrè Visual Archives, American Institute of Physics.

Niels and Margrethe Bohr, on the motorcycle of George Gamow, 1930. Source: Emilio Segrè Visual Archives, American Institute of Physics.

The Bohr letters released in 2002 are an example of this. Bohr’s letters to Heisenberg, which are very condemnatory, have been sometimes naively cited as “proof” of whatever took place. They are not. They were written after Bohr had read an account of the German bomb project (Robert Jungk’s Brighter than a Thousand Suns) which implied (in a footnote) that Heisenberg was claiming to have sabotaged the German project on moral grounds. Bohr, infuriated that Heisenberg might be saying such a thing, wrote a strongly-worded language arguing for the opposite. Historians now know — having looked at Jungk’s papers — that in fact Heisenberg’s letter to Jungk was mis-quoted by the latter, missing sentences where Heisenberg clearly backs away from such an implication. In any case, the point is simple enough: Bohr’s letters, written a decade later, were the angry assertions of someone who thought Heisenberg was trying to make a specific sort of claim, and Bohr was intent on disabusing him of the notion. One might also point out (as the play does) that in the end, Bohr was the one who did contribute towards making a weapon of mass destruction, not Heisenberg, and for Bohr to think that Heisenberg was attempting to claim a moral high-ground as a result would have been particularly galling.

It doesn’t mean there isn’t a grain of truth in Bohr’s letters. But decade-old memories conjured up in a moment of anger and misapprehension, at best, are the subjective memories of one individual, and at worst, may be unreliable even as those. And memories are, of course, tricky things, as any psychologist will tell you.

In any case, a historian would probably also argue that this doesn’t matter too much. One meeting is generally not the stuff that history is made of. Even if Heisenberg had said, in the strongest terms, that the Germans weren’t building a bomb, it would have not changed much of history — the momentum was far too great in the Allied project by the time Bohr got to it, and there are few who likely would have believed him without concrete proof.

Allied troops disassembling the German experimental research reactor at Haigerloch, as part of the Alsos mission. Source: Wikipedia.

Allied troops disassembling the German experimental research reactor at Haigerloch, as part of the Alsos mission. Source: Wikipedia.

But it might appear to give an one of those questions that people have been asking since 1945: why did the Germans fail to get an atomic bomb? But here also is where the historians might be annoying and pedantic. There are very few historians who believe that Heisenberg (or any of the Germans working on the project) were actively trying to avoid making an atomic bomb. Frayn’s play in many ways tries to “sit on the fence” on this issue, but in doing so the play ends up creating something of the “false balance” fallacy, giving equal time to a side that is not considered very plausible by most. It leaves up in the air whether Heisenberg was trying to sabotage (consciously or not), making it seem that this is as equally plausible an interpretation as any other.

This can be misleading. Some members of the German atomic program — Carl Friedrich von Weizsäcker was the main one — did try to claim, after the war, that the reason the Germans didn’t make an atomic bomb was because they didn’t want to make an atomic bomb. Heisenberg himself generally danced elliptically around this claim, never quite (to my knowledge) advocating it, but also describing his actions during the war with enough vagueness as to leave open the possibility that part of him, perhaps subconsciously, didn’t succeed because he didn’t want to. The “Heisenberg was a saboteur” thesis was given prominence in Thomas Power’s Heisenberg’s War (2000), but other than that, it is not present in the claims of pretty much any other recent history on the topic.1

The reason why is simple enough: there isn’t any proof of it. In fact, it seems to have been offered up, quite post-hoc, as an explanation while the German scientists were being interred at Farm Hall and trying to grapple with the meaning of Hiroshima. It also doesn’t really square with any of the actions of the Germans during the war: they were working quite hard. If one is to assume they did any “sabotage,” it must have been extremely subtle, so subtle as to be indistinguishable from them doing the opposite of sabotage.2

Instead, through many other books (which I have discussed in another post), we have a pretty good picture of the German atomic program, how it was decided that it would pursue reactors, not bombs, and how paltry it was in comparison to the Allied effort. As I have stated elsewhere, the interesting historical question for me is less why didn’t the Germans but rather why did the Americans? Because the American case is the anomaly, not the German case. To decide whether an atomic bomb could be made rapidly with the knowledge available in 1941 involved a non-trivial prediction of the future. The Americans ended up (for various reasons) thinking it could be done; the Germans thought it was not worth the risk and expense. The Americans, in any case, barely pulled it off. Had their schedule been off by a few months, there would have been no atomic bombs ready for use during World War II, and the Manhattan Project still holds the world record for fastest time between deciding to make a nuclear weapon and actually having one.

Heisenberg and Bohr in Copenhagen in the early 1930s. Source: Emilio Segrè Visual Archives, American Institute of Physics.

Heisenberg and Bohr in Copenhagen in the early 1930s. Source: Emilio Segrè Visual Archives, American Institute of Physics.

But I digress. If Copenhagen errs this is where it errs: it presents, on balance, a case that is remarkably sympathetic to the idea that Heisenberg et al. purposefully sabotaged the German bomb program. This is not what most historians see in the historical record. In its fallback position, the play presents the idea that the German bomb program was a failure on a very basic technical level — that nobody had run the critical mass equation correctly, that nobody had realized a few very basic ideas. And while it is true that there were some errors in the German calculations, they were not nearly so ignorant of these matters as the play would have you believe. They knew what plutonium was. They knew what atomic bombs could be. There were those within the German program (which was not one single program in any case, but several different groups) who knew that the critical mass of enriched uranium would be fairly low (German Army Ordnance thought in 1942 that between 10-100 kg of U-235 would give you a bomb, which is a spot-on estimate). Their problem was not one of basic technical errors. Heisenberg made some technical errors, but he was not the only one on the project.

There are many other, more interesting reasons to attribute the failure of the German bomb project. They lacked the fear of an Allied project that the Allies had of them. They feared over-promising with regards to a risky endeavor. During the later parts of the war, they suffered from supply setbacks due to their being targets of bombing and sabotage raids. They lacked anything like a Leslie Groves or Lavrenty Beria figure who could push the work through, against all odds and setbacks, in the limited amount of time that it might have been successful. But this is an area where I don’t want to overrepresent a historical consensus, though: practically every historian who writes on the topic of the German atomic bomb has a slightly different reason to argue why they didn’t make one. (If you read the volume of essays on Copenhagen I mentioned earlier, Copenhagen in Debate, the overwhelming feeling one gets is that practically every historian in there thinks Frayn is wrong, but they disagree greatly on exactly why the Germans didn’t get the bomb.)

So, does this mean that that I don’t like Frayn’s play? No! I actually like the play a lot. It just shouldn’t be anyone’s primary source for information about what happened during the German bomb project. But I don’t think it’s any worse in terms of confusing people than, say, many History Channel documentaries are. Popularizations of history often get things a bit wrong, sometimes a lot wrong — that doesn’t keep me up at night.

Same scene as above, different moment. Source: Emilio Segrè Visual Archives, American Institute of Physics.

Same scene as above, different moment. Source: Emilio Segrè Visual Archives, American Institute of Physics.

The moral questions the play raises, the way it encourages people to view historical record as something complex and evolving, and the way in which it emphasizes that changing the questions you ask of history can lead you to see different aspects of it (in a deliberate analogy to Bohr’s Complementarity), are all quite important and interesting things to think about. I think Frayn’s play manages to get a lot right about what history itself is, and how it is formed on the back of inscriptions and memories and uncertainties and understandings that shift over time. In my mind, those are the really important things to get out of a play.

And let’s be honest: how many people — even professional historians! — would care about the ins-and-outs of the history of the German atomic project if not for this play? It raised the awareness of historical scholarship on this question to new heights, even if much of that scholarship is arguing against some of the implications people take away from the play. But it made that scholarship seem relevant. It makes people ask me about Heisenberg. That’s a good thing, and a needed thing. I would much rather people take an interest in this subject, and maybe run the risk of having different views than the majority of historians, than the contrary, which is that they don’t know or care anything about it at all. Of course, there are limits to this sort of attitude.

Frayn’s errors are ones of subtle historical interpretation, and don’t seem (in Frayn’s case) to be motivated by any sort of overarching political or historical agenda. (Unlike the case of von Weizsäcker, for example.) I’m inclined to give them a “pass” for the sake of making interesting entertainment that gets people asking questions. The one error that Frayn’s play essentially avoids is the more common popular error about the German bomb project, which claims that there was a true “race for the bomb” in which the world very narrowly avoided the Nazis getting nuclear weapons before the Americans did. This is a much more insidious sort of erroneous history, in my mind, because it is used to paper over the moral questions on the American side of things, and commits a multitude of factual sins in the process. The question of whether Heisenberg was a saboteur or not is not on that level, even if I think the bulk of the historical profession would not agree with Frayn that it is as likely an explanation for the German failure as any other.

Notes
  1. Frayn has always claimed that he was not advocating this thesis explicitly, but in his interactions with historians since writing the play (and it underwent a few revisions), he drew it (and himself) closer to the “Heisenberg was a saboteur” thesis. Perhaps this was a defensive gesture, perhaps he really believes it, perhaps it appeals to him as a playwright (Heisenberg-as-tormented is a much more interesting figure, as far as characters go, than Heisenberg-as-clueless or Heisenberg-as-someone-with-different-priorities). []
  2. Heisenberg’s misquoted letter to Jungk, which set off the Bohr correspondence, was addressing this point — he was implying that under a dictatorship, trying to distinguish between a true-believer and someone who is just-playing-along is going to be almost impossible. However in the sentence Jungk omitted, he makes clear that he was not implying that he was a saboteur. In the edition of Brighter than a Thousand Suns that Bohr read, Jungk quoted Heisenberg as saying that, “In a dictatorship active resistance can only be practiced by people who seemingly take part in the system. When someone speaks openly against the system, he quite certainly deprives himself of any possibility of active resistance.” But Heisenberg then quickly backtracked: “I would not want this remark to be misunderstood as saying that I myself engaged in resistance to Hitler. On the contrary, I have always been ashamed in the face of the men of 20 July (some of whom were friends of mine), who at that time accomplished truly serious resistance at the cost of their lives.” Jungk did not quote the latter. See Cathryn Carson, Heisenberg in the Atomic Age: Science and the Public Sphere (New York: Cambridge University Press, 2014), 402-403. []
Redactions

When did the Allies know there wasn’t a German bomb?

Friday, November 13th, 2015

Fears of a German nuclear weapons program were the initial motivating concerns behind pushes in both the United States and the United Kingdom. Leo Szilard and Albert Einstein in the United States, and Otto Frisch and Rudolf Peierls in the United Kingdom, among others, were worried sick of the prospect of a Nazi atomic bomb. That these scientists were European émigrés of Jewish descent played no small role in their fears.

Diagram (left) and replica (right) of the Haigerloch reactor that Heisenberg and his team were trying to complete by the end of the war. Source: diagram is from Walker's German National Socialism and the Quest for Nuclear Power, 1939-1949, replica photo is from Wikipedia.

Diagram (left) and replica (right) of the  Haigerloch heavy-water moderated reactor that Heisenberg and his team were trying to complete by the end of the war. The cubes are of unenriched uranium metal. Source: The diagram is from Walker’s German National Socialism and the Quest for Nuclear Power, 1939-1949, the replica photo is from Wikipedia.

But eventually we came to find that the German atomic bomb project was stillborn. The Germans had a modest atomic power project, researching nuclear reactors, but were in no great rush for an atomic bomb. Of course, they are not necessarily unrelated projects — you can use nuclear reactors to produce plutonium. But it would require a much greater effort to do so than the Germans were engaged in. By any metric, the Germans were involved in a research program, not a production program. Their work was relatively small-scale, not a crash effort to get weaponized results.1

When did Manhattan Project officials know that the German program was not a serious threat, though? That is, when did they know that there was virtually no likelihood that the Germans would develop an atomic bomb in time for use in World War II? This is a question I get a lot, and a question that comes up in this season of Manhattan as well. It’s an important and interesting question, because it marks, in part, the transition from the Anglo-American bomb project from being an originally defensive project (making an atomic bomb as a deterrent against a German bomb) to an offensive one (making a bomb as a first-strike weapon against another non-nuclear country, Japan).

What makes this a tricky question to answer is that the word “know” is more problematic than it might at first seem. Historians of science in particular, because we are historians of knowledge, are quite aware of the ways in which “knowing” is less of a binary state than it might at first appear. That is, we are ordinarily accustomed to talk about “knowing” as if it were a simple case of yes or no — “they knew it or they didn’t.” But knowledge often is more murky than that, a gradient of possibilities. One might have suspicions, but not be sure. The amount of uncertainty can vary in all knowledge, and sometimes be deliberately encouraged or exaggerated to create a space for action or inaction. One’s knowledge can be incomplete or partially incorrect. And there are many different “levels” of knowledge — one might “know” that the Germans were working on reactors, but not know to what ends they were intending to use them.

Allied troops disassembling the German experimental research reactor at Haigerloch, as part of the Alsos mission. Source: Wikipedia.

Allied troops disassembling the German experimental research reactor at Haigerloch, as part of the Alsos mission. Source: Wikipedia.

At one end of the “knowledge” question, we can point to the success of the Alsos mission. Alsos (Greek for “Groves”) was an effort in which Allied scientific and intelligence officers moved into German sites along with the invading troops, seizing materials, facilities, and even scientists (the latter being eventually detained at Farm Hall). By November 1944, Samuel Goudsmit, the scientific leader of the Alsos mission, had concluded that the German program appeared stillborn. By the spring of 1945, of course, they had made sufficient progress into Germany to know for sure. So that is a definite back-end on when they “knew” that the Germans had no bomb.2

But what did they know before that? At what point did the Germans stop being the fear that they had once been? This is the far more interesting, trickier question.

Among the American scientists, the fears of a German bomb peaked sometime in mid-1942. This, not coincidentally, is exactly when the Americans decided to accelerate their program from the research phase into the production phase: when their work changed from thinking about whether atomic bombs were possible to actually trying to build them. As the Americans became more convinced that atomic bombs were feasible to build in the short-term, they became more worried that the Germans were actually building them, and might have started building them earlier than the Americans. Arthur Compton, Nobel Prize winning physicist and head of the University of Chicago Metallurgical Laboratory, wrote several particularly impassioned memos in the summer of 1942, urging an acceleration of atomic work largely out of fears of a German bomb:

We have recently become aware that the threat of German fission bombs is even more imminent than we supposed… If the Germans know what we know — and we dare not discount their knowledge — they should be dropping fission bombs on us in 1943, a year before our bombs are planned to be ready.”3

Compton’s fears appear genuine, and rest on the conservative assumption that the Germans were just as smart, and just as aware of the possibilities, as the Americans. (And we know that they were, in fact, aware of all of these possibilities at the exact same time — but the Germans judged the effort more difficult, and more risky, than the Americans did.) There is no other basis for Compton’s assumptions, as he had no access to intelligence information on German efforts (and, indeed, his memo calls for more work in that field). But they were also self-serving, because they encouraged more effort towards his own goal, which was to accelerate the American bomb program. Compton was not at all alone in these fears; Harold Urey, James Conant, and Ernest Lawrence were all quick to point out that the American effort had been relatively slow to start, and that the Germans had clever scientists who ought not be underestimated.

The palpable fears of Arthur Compton, June 1942.

The palpable fears of Arthur Compton, June 1942.

Up until 1942, these fears were not, arguably, unwarranted. The Germans and the Americans were in similar positions. But, in a touch of irony, at the moment the Americans decided to switch towards developing a workable bomb, the Germans instead were deciding that they no longer needed to prioritize the program. They had concluded it would be an immense effort that they could ill afford to undertake, and that it was extremely unlikely that the Americans (or anyone else) would find success in that field.

So when did the picture change with regards to US knowledge, and who was told? Over the course of 1943 and 1944, more and more intelligence was gathered that, added up, began to suggest that the Germans did not have much of a project. In late 1943, General Leslie Groves appointed a specific intelligence group to try and suss out information about the enemy’s work. One of their avenues of approach was better collaboration with the intelligence services of the United Kingdom, who had far better networks both in Germany and in neutral countries than did the Americans. They even had a spy within Germany, the Austrian chemist Paul Rosbaud, who worked at Springer-Verlag, the scientific publisher. By the end of 1943, the British had concluded that the German program was not going anywhere. They were able to account for Heisenberg’s movements all too easily, and there seemed to be no efforts to industrialize the work on the scale necessary to produce concrete results in the timescale of the war. This information was duly passed on to the Manhattan Project intelligence services.4

Did it have any effect? Not immediately. The Americans were not entirely sure whether the British assessments were accurate. As Groves put it in a memo to Field Marshall John Dill in early 1944:

We agree that the use of a TA [“Tubealloys” = atomic] weapon is unlikely. The indirect and negative evidence developed by your agencies to date is in support of this conclusion. But we also feel that as long as definite possibilities exist which question the correctness of this opinion in its entirety or in part we cannot afford to accept it as a final conclusion. Repeated reports that the enemy has sufficient raw material and the fact of the early interest of enemy scientists in the problem must be explained away before we can safely disregard the possible use of this weapon.5

Groves was being conservative about the intelligence — none of it definitely proved that the Germans weren’t working on a bomb, they just were reporting that they couldn’t see a bomb project. This is a common bind for interpreting foreign intelligence: just because you don’t see something, doesn’t mean it isn’t there (you may have missed it), but on the other hand, proving a negative can be impossible. (This problem, as I am sure the reader appreciates, still exists with regards to alleged WMD programs today.) In Groves’ mind, until there was really zero basis for doubt, they had to proceed as if the Germans were building a bomb.

1944-01-17 - Groves to Dill - R05 T08 F18

But over the course of 1944, there are many accounts which indicate that the Americans at the top of the project, at least, were fearing a German bomb less and less. When Secretary of War Henry Stimson briefed several select Congressmen on the bomb work in February 1944, he had emphasized that “we are probably in a race with the enemy.” By contrast, when he briefed some of the same Congressmen that June, Stimson told them that “in the early part of this effort  we had been in a serious race with Germany, and that we felt that at the beginning they were probably ahead of us.” Note the past tense — at this point, they were using the fears of the German bomb project to justify their earlier efforts, not their current ones. Vannevar Bush, who was at the meeting, emphasized in his notes that he told the Congressmen a bit more about “what we know and do not know about German developments,” but concluded with the thought that since the Allies began the heavy bombing of German industrial sites, the odds were that the Americans were “probably now well ahead of them.”6

Finally, in late November 1944, Samuel Goudsmit, head of the Alsos project, concluded that after inspecting documents, laboratory facilities, interviewing scientists, and doing radiological surveys of river water, that “Germany had no atom bomb and was not likely to have one in a reasonable time.” This was reported back to Groves, who appears to have not been entirely convinced until the total confiscation of German material and personnel was completed in the spring of 1945 and the end of the European phase of World War II. Even Goudsmit was unsure whether the conclusion was justified until they had confirmed it with further investigations.7

By the end of 1944, even the scientists at Los Alamos seem to have realized that Germany was no longer going to be the target. Joseph Rotblat, a Polish physicist in the British delegation to the laboratory, was the only one who left, later saying that “the whole purpose of my being in Los Alamos ceased to be” once it was clear the Allies weren’t really in a “race” with the Nazis.8

Several members of the Alsos mission, with Samuel Goudsmit, the scientific director, at far left. Source: Wikipedia.

Several members of the Alsos mission, with Samuel Goudsmit, the scientific director, at far left. Source: Wikipedia.

So, in a sense, the final confirmation — the absolute confirmation — that the Germany didn’t have an atomic bomb only came when the Germans had totally surrendered. By late 1944, however, it had become clear that their bomb project was, as Goudsmit put it, “small-time stuff.” By mid-1944, the top American civilian official (Stimson) was already minimizing the possibility of German competition. By the end of 1943, British intelligence had concluded the German program was probably not a serious one. We have here a sliding scale of “knowledge,” with gradually increasing confidence, with no clear point, except arguably the “final” one, to say that the Allies “knew” that they were not in a race with the Germans. For someone like Groves, it was convenient to point to the uncertainty of the intelligence assessments, because the possibility of a German bomb, even one very late in the war, was so unacceptable that it could be used to justify nearly anything.

How much does it matter? Well, it does complicate the moral or ethical questions about the bomb project. If you are making an atomic bomb to stop Hitler, well, who could argue with that? But if you are making a bomb to use it against a non-nuclear power, to use it as a military weapon and not a deterrent, then things start to get problematic, as several scientists working on the project emphasized. Even Vannevar Bush, who supported using the bomb on Japan, emphasized this to Roosevelt in 1943, telling the President that “our point of view or our emphasis on the program would shift if we had in mind use against Japan as compared with use against Germany.”9

The degree to which the goals of the atomic bomb program shifted — from building a deterrent to building a first-strike weapon — is something often lost in many historical descriptions of the work. It makes the early enthusiasm and later opposition of some of the scientists (such as Leo Szilard) seem like a change of heart, when in reality it was the goals of the project that had shifted. It is, in part, a narrative about the shifting of perspective from Germany to Japan. Like the Allied knowledge of the German program, it was not an abrupt shift, but a gradual one.

Notes
  1. The best source for what the Germans were actually doing is still Mark Walker, German National Socialism and the Quest for Nuclear Power, 1939-1949 (Cambridge: Cambridge University Press, 1989), and Mark Walker, Nazi Science: Myth, Truth, And The German Atomic Bomb (New York: Plenum Press, 1995). []
  2. Of course, this assumes Alsos got everything right, and it is not entirely clear that they did. There are still several interesting historical questions to be answered about the German program. As I’ve written elsewhere, I don’t think Rainer Karlsch’s work on the German atomic program is compelling in its final thesis, but many of the documents he has found do point towards the Alsos mission having some limitations in what it was able to find and recover, and towards further work to be done in fully understanding the German program. []
  3. Arthur Compton to Vannevar Bush (22 June 1944), copy in Bush-Conant File Relating the Development of the Atomic Bomb, 1940-1945, Records of the Office of Scientific Research and Development, RG 227, microfilm publication M1392, National Archives and Records Administration, Washington, D.C., n.d. (ca. 1990), Roll 7, Target 10, Folder 75, “Espionage.” Compton refers to “copper,” which was then the American code-name for plutonium, and “magnesium,” a code-name for enriched uranium. []
  4. The best overall source on US efforts to get information about the German bomb program, and the source of much of this paragraph’s information, Jeffrey Richelson, Spying on the Bomb: American Nuclear Intelligence from Nazi Germany to Iran and North Korea (New York: W.W. Norton, 2006), chapter 1. []
  5. Leslie R. Groves to John Dill (17 January 1944), copy in Correspondence (“Top Secret”) of the Manhattan Engineer District, 1942-1946, microfilm publication M1109 (Washington, D.C.: National Archives and Records Administration, 1980), Roll 5, Target 8, Folder 18, “Radiological Defense.” []
  6. Vannevar Bush to H.H. Bundy (24 February 1944), and memo by Vannevar Bush on meeting with Congressmen (10 June 1944), copies in Correspondence (“Top Secret”) of the Manhattan Engineer District, 1942-1946, microfilm publication M1109 (Washington, D.C.: National Archives and Records Administration, 1980), Roll 2, Target 8, Folder 14, “Budget and Fiscal.” []
  7. Samuel Goudsmit, Alsos (New York: H. Schuman, 1947), on 71; see also Richelson, Spying on the Bomb, chapter 1. []
  8. Joseph Rotblat, “Leaving the bomb project,” Bulletin of the Atomic Scientists (August 1985), 16-19, on 18. See also my post discussing some of the alternative/contributing factors regarding Rotblat’s leaving the project, as discussed by Andrew Brown in his book, The Keeper of the Nuclear Conscience: The Life and Work of Joseph Rotblat (New York: Oxford University Press, 2012). []
  9. Vannevar Bush, “Memorandum of Conference with the President” (June 24, 1943), copy in Bush-Conant File Relating the Development of the Atomic Bomb, 1940-1945, Records of the Office of Scientific Research and Development, RG 227, microfilm publication M1392, National Archives and Records Administration, Washington, D.C., n.d. (ca. 1990), Roll 2, Target 5, Folder 10, “S-1 British Relations Prior to the Interim Committee No. 2.” []
Meditations

When bad history meets bad journalism

Wednesday, January 7th, 2015

A lot of people have been passing around the latest news story about the supposed “Nazi nuclear bunker” that was supposedly discovered in Austria. Normally I would not comment at length about such a thing, originating from tabloids and so obviously (to my eye) devoid of serious merit. But since the passing around has even made it to more austere publications (like the Washington Post) and because a number of people have asked me informally what I thought about it, I thought I could take it as an opportunity to talk about what bad history of the bomb looks like.

The Sunday Times (UK) version of the "bunker" story.

The Sunday Times (UK) version of the “bunker” story.

Cheryl Rofer has compiled some of the basics of the story on Nuclear Diner. The basics are this: an Austrian filmmaker named Andreas Sulzer has been trying to make a film about an Austrian bunker that dates from World War II. He has been claiming there was a nuclear connection to this bunker, and gotten some headline-grabbing tabloid stories about it, since 2013. What’s the evidence for it being a nuclear site? He claims that he has an American intelligence document from 1944 that lists it as a site of possible interest. He has made vague claims about radioactivity. It is part of an existing weapons production plant (a factory that produced rocket engines). Some physicists might have been sent there. Did we mention there was a bunker?

Yeah. That’s it. This stuff is pretty obviously thin, but let’s just say: Allied intelligence about German nuclear sites in 1944 was poor and scattered and means nothing. Radiation is everywhere and can fluctuate from a variety of natural and artificial sources — only by talking about levels of radiation do we start to wonder if something unusual is occurring, and only by talking about specific radioactive isotopes can we start to really wonder if any given radiation is of interest to us or not. (This is not hard to do — there are hand-held devices that can both measure radiation intensity and determine the isotopes in about 30 seconds, these days.1) The fact that it is part of an existing plant is probably evidence against it being a super-secret nuclear installation (compartmentalization). And physicists were involved in practically every technical program during World War II, so their presence tells us nothing one way or the other.

Forbes' version of the same story from February 2014.

Forbes’ version of the same story from February 2014.

The obvious thinness of this evidence, and the obvious motivation of the filmmaker — who has been denied a permit to dig around the site — should already be a sign to any self-respecting journalist that this is not worth touching. Certainly not without talking to some other experts about it. The only person anyone seems to have called up is Rainer Karlsch, whose own work on the German nuclear program is extremely controversial (Karlsch claims the Germans detonated some kind of dirty bomb or pure-fusion bomb — also on very thin evidence). For all of his outsized claims, at least Karlsch did his homework and tries to marshall evidence for his work. I don’t think Karlsch’s evidence fits the strength of his claims, and there are real technical problems with Karlsch’s reasoning, but there is at least a serious scholarly discussion to be had there. There is not one to be had (at least, not yet) about the Sulzer claims, because there is no there there. Karlsch’s only quoted comment is that he thinks the Germans got further along with their nuclear program than most people think (to be addressed below), and doesn’t comment on the Sulzer claims at all — which makes it not really a supporting comment for Sulzer at all.2

But if you slap “Nazi” and “nuclear” onto something, it gets a lot of hits, and that’s what appears to be the motivation here both for the Sunday Times and the many other sources that have picked up the same story and run it without checking in with anybody else to see whether it is even plausible. Which is a sad state of things.

December 2013 version of the story, from the Daily Mail (UK).

December 2013 version of the story, from the Daily Mail (UK).

There is a bunker. No credible evidence has actually been offered to make one think it has a nuclear connection. That the Germans had large underground bunkers for technical projects is well-known — that they had them for their nuclear program is not, because there is no evidence of this. (They did do some reactor work in some caves towards the end of the war, but it was small scale.) Newspapers should stop passing this kind of nonsense around… especially since it is not even “news” at this point — the bunker story has been circulating for over 2 years, without any additional increase in credibility!

About two or three times a year I get contacted by people who are working on things relating to the German or Japanese wartime nuclear programs. The appeal is obvious: there is a built-in audience for this kind of thing, and there are still areas of uncertainty with regards to these programs. I have written on here in the past on a few of the questions I’ve stumbled into with regards to the German program, for example. We don’t know everything about these programs, and there are reasons to think that there is still more to learn. So I’m always willing to engage with people on these questions.

At least the Washington Post hedged the headline a bit, "says he uncovered." Still misleading, but makes the factual basis a little more clear.

At least the Washington Post hedged the headline a bit, “says he uncovered.” Still misleading, but makes the factual basis a little more clear.

Some of the stuff strikes me as improbable or a little crack-pot-ish; some of it seems plausible and interesting. I’m a firm believer in the idea that sometimes non-academic historians stumble onto interesting things and interesting questions (John Coster-Mullen is a great example of this), and I don’t discriminate unless people show themselves to be going down truly untenable paths (like that small segment of the Internet who believes that all nuclear weapons are a hoax, which is just a truly silly “theory”).3 I will hear just about anyone out, and tell them what I find plausible or implausible about their ideas. I am a skeptical person — big claims need big evidence. But I do believe there is still a lot “out there” to be found on these topics, and maybe more than a few surprises yet.

The German nuclear program seems to attract a lot of “theorizing” in particular, ranging from the “they got further in it than most people think” (which is an easy argument to make since most people don’t know much about the German program at all) to the absurd extremes of “they made an atomic bomb and the only way the Americans got one themselves was by stealing it” (conspiracy country).

The 1945 version of the same headline — New York Herald Tribune, August 8, 1945, story about the Norsk Hydro plant, which also over-emphasized the closeness of Germany's getting the bomb for dramatic effect.

The 1945 version of the same headline — New York Herald Tribune, August 8, 1945, story about the Norsk Hydro plant, which also over-emphasized the closeness of Germany’s getting the bomb for dramatic effect. Click the image to read the article.

Public understanding of the German nuclear program is indeed a confused and often incorrect thing, owing to a history of the politicization of the topic. In the very early days after the dropping of the atomic bomb on Hiroshima, the “race with the Germans” narrative was played up very heavily by the Manhattan Project public relations people, both because it made for good drama and because it seemed to justify the US interest in the topic. And, indeed, the scientists who lobbied for the atomic bomb program between 1939 and 1944 or so did believe that the Germans might be ahead of them and that they were “racing” them to make the atomic bomb. It was not until late 1944 that the Alsos program reported back that the Germans had never gotten very far with their work, and that the US had never really been “racing” with them at all. Even today, though, we still see the legacy of this, with television programs and movies over-dramatizing the closeness of the “race,” and the importance of things like the sabotage of the Norsk Hydro facility, all of which makes it look like the Germans were very close indeed.

On the other side of the coin, we also have things like the Copenhagen play, which is an excellent piece of drama (and I am indeed a fan) but has infected a new generation with the idea that the Germans made no progress at all with regards to nuclear weapons — and indeed, had never even seriously considered the matter — because Heisenberg had consciously sabotaged the whole project. Never mind that Heisenberg’s own claims were far more nuanced on this point (he was always vague on this, only implying in a round-about way that they might not have made a bomb because they didn’t really want one). The play and the press around it has led a lot of people to think that the Germans knew really nothing about nuclear weapons development, and that they had intentionally avoided making them.4

Allied troops disassembling the German experimental research reactor at Haigerloch, as part of the Alsos mission.

Allied troops disassembling the German experimental research reactor at Haigerloch, as part of the Alsos mission.

The truth, so far as we know it now, is somewhere other than these two extremes. Mark Walker’s two books (German National Socialism and the Quest for Nuclear Power, 1939-1949 and Nazi Science: Myth, Truth, And The German Atomic Bomb) are still excellent, though a bit more has come out since then. The basic gist of Walker’s work is that the German program knew a lot on paper, but never quite crystallized everything organizationally or technically to keep their program from being anything more than a side-project, focused primarily on reactor development. They never developed large-scale isotopic enrichment facilities, and they never got a reactor that went critical. Their reactor work was sophisticated given the conditions under which it was being done, but it never achieved criticality. Some members of the various teams that worked on the project had some fairly accurate understandings of how a nuclear weapon might be made, but there was also a lot of confusion circulating around (some members of the team understood it would be a fast-neutron fission reaction in enriched material, some were confused and focused on it being basically an out-of-control pile). Some were considering rather advanced designs (Karlsch has convinced me that they thought a bit about implosion, for example), but the whole thing was mostly a exploratory program.

The plausibility of any new arguments about German successes with their nuclear programs is always limited in part by what we know about the technical requirements of such an endeavor. The Manhattan Project need not be the only model of a successful nuclear program (it was in many ways unusual), but it does provide some baseline metrics for talking about nuclear programs of the 1940s. Any successful plutonium-breeding program is going to require fairly large reactors, because plutonium reprocessing extracts only grams of “product” from each ton of uranium fuel that goes into it. (Each of the three early Hanford reactors extracted only 225 grams of plutonium from every ton of uranium processed.) Any successful isotopic-enrichment program is going to require huge feed supplies of uranium (the Manhattan Project approaches consumed thousands of tons of uranium), pretty large facilities, and a lot of electricity.

When Alsos leader Sam Goudsmit was investigating the Germany nuclear work, he was struck by how little of it was kept very secret — evidence, in his mind, that they had not gotten very far with it. (S.A. Goudsmit and F.A.C. Wardenburg, "TA-Straussburg Mission," (8 December 1944), copy in the Bush-Conant file, Roll 1, Target 6, Folder 5.)

When Alsos leader Sam Goudsmit was investigating the Germany nuclear work, he was struck by how little of it was kept very secret — evidence, in his mind, that they had not gotten very far with it. (S.A. Goudsmit and F.A.C. Wardenburg, “TA-Straussburg Mission,” (8 December 1944), copy in the Bush-Conant file, Roll 1, Target 6, Folder 5.)

Separate from the technical argument is a bureaucratic one — if the Germans supposedly made such progress, why is was there no organizational evidence of it in the copious reports, papers, formal and informal statements, and so on that were discovered by the Alsos project, later researchers, and at Farm Hall? Big programs leave big traces. If one wants to claim that the German program was big, one has to show where those traces are, or come up for a plausible argument for why there are no traces.

This does not mean that one might not find more evidence in the future. It just means that any claims and evidence need to fit within the existing technical and bureaucratic narratives. For example, one could argue, “oh, but they did have a massive isotopic enrichment plant, and it was here, and here is evidence of — if one had the evidence. On the bureaucratic side, one could argue that people who we previously thought were important in the program (e.g. Gerlach) were actually out of the loop entirely. Or something along those lines.

Weekly World News, 2002: "Confederacy was Building an Atomic bomb."

Weekly World News, 2002: “Confederacy was Building an Atomic bomb.” No comment!

But you can’t just find a hole in the ground and say, “ah, here is where Hitler was making a bomb.” Aside from the implausibility of a nuclear program existing in a single underground bunker, by itself this kind of claim hasn’t done the work to be plausible. At best, if done in good faith, it is a claim along the lines of “oh, maybe this is worth looking into more.” That is fine — hey, I’d even nominally support that — but one shouldn’t be going to the newspapers about it at that stage, and the newspapers shouldn’t be passing off your claim as having more validity than half of the other implausible claims that circulate around these topics. This is premature, and the net effect is going to be misleading for the readership.

As historians, we need to be open to the idea that there are still mysteries to be solved, secrets to be unearthed, even about ground that superficially looks well-trodden. But I wish journalists would do a little better than just re-printing the overblown claims of unreliable sources, without checking with experts on their plausibility. Couching it as, “this guy made a claim” doesn’t get you off the hook, because we all know that only the initial, big-claim story is the one that will be passed around, and that almost nobody will notice when no follow-ups occur, or the mild “so no evidence turned up for this guy’s big claim” story comes out.

Journalists — You can do better!

Notes
  1. I got to see a demonstration of the lanthanum bromide detectors that U.S. Customs and Border Protection uses at Port Newark a few weeks back — they were pretty neat. Totally hand-held, hold it up to something interesting and click a button and 30 seconds later it tells you what isotope it is, color-coded by whether it is natural in origin, a medical isotope, or something with nuclear weapons relevance. []
  2. Karlsch’s work deserves to be gone over more carefully. Its lack of translation into English has probably inhibited this to some degree. Karlsch has found some interesting documents, but I am not sure they add up to what he claims they do. For example, Karlsch and and Mark Walker published an article in 2005 where they claimed they had a diagram of a Nazi atomic bomb — it is clearly not one. For one thing, it has “plutonium” (the American term for Element 94) labeled on it, which clearly dates it as a postwar creation. And for another thing, it is probably a crib from Hans Thirring’s 1946 Die Geschichte der Atombombe, which itself is explicitly based on the Smyth Report. Karlsch’s work is filled with a muddled discussion of pure-fusion concepts (which wouldn’t work), dirty bombs, atomic bombs of various sorts, “mini-nukes,” and all sorts of other indications of a less-than-complete understanding. []
  3. For those who are curious: The “all nukes are a hoax” theory seems to stem from a couple different sources. The technical argument is that fast neutron chain reactions are impossible, because the fission cross-section of U-235 is small for fast neutrons. The cross-section is indeed small for high-energy neutrons, which is why reactors use a moderator to slow the neutrons down and increase the likelihood of their capture by the small amounts of U-235 in the nuclear fuel. What is weird is that the people making this argument don’t seem to realize that this is exactly why you use 80-90% enriched material in a bomb — it is to overcome this low probability of fissioning by just putting a ridiculous number of targets in the area. It is also why there are tampers, neutron reflectors, and the like, and also why even a relatively sophisticated weapon like the Fat Man only fissioned something like 13-18% of its fissile material, and the Little Boy bomb only fissioned around 1% of its fissile material. They also have weirdly interpreted the “Hiroshima and Nagasaki are not that different from the firebombing of Tokyo” argument (to a rather absurd conclusion, that it was just a firebombing, despite the fact that firebombing and atomic bombing have really different outcomes), believe that the photographs of the mushroom clouds are all faked (despite the fact that such a level of fakery was really quite beyond the technology of the 1940s — similar to the “Apollo moon hoax,” it would have been easier to make an atomic bomb in the 1940s than to fake an atomic bomb convincingly on film, at least to the degree of documentation that we have on them from the time), and believe that every scientist in the entire world (except for the random engineer who came up with this dumb theory) is in on the secret and has reasons to propagate it indefinitely (and I am apparently in on the hoax as well, to my surprise). The one person I e-mailed with about this, just trying to see what the limits of their rationality were and what it spawned from, eventually let on that to him, one of the most convincing pieces of evidence for this theory is the number of Jews who were involved in the creation of the bomb, wink wink, nudge nudge. This probably hits at the real origin of this bad idea — just another form of mis-matched anti-Semitism grafting itself onto another source. That my last name is a Jewish-sounding one did not apparently resonate with the person e-mailing me. []
  4. On the backs-and-forths of the Heisenberg story, see esp. Mark Walker, German National Socialism and the Quest for Nuclear Power, 1939-1949 (Cambridge: Cambridge University Press, 1989), 204-221, and the essays in Matthias Dörries, Michael Frayn’s “Copenhagen” in Debate: Historical Essays and Documents on the 1941 Meeting Between Niels Bohr and Werner Heisenberg (Berkeley, CA: Office for History of Science and Technology, UC Berkeley, 2005). []
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Heisenberg’s Dresden story: A wartime atomic mystery

Friday, October 11th, 2013

One of the weirdest stories I’ve come across regarding the Nazis and the atomic bomb is the one that the German physicist Werner Heisenberg told at Farm Hall about being asked about an apparent rumor that the United States was planning to use an atomic bomb against Dresden.

The Farm Hall transcripts reports him telling it several times during his internment, and it changed slightly each time he told it. Here’s the first version:

About a year ago, I heard from Segner from the Foreign Office that the Americans had threatened to drop a uranium bomb on Dresden if we didn’t surrender soon. At the time I was asked whether I thought it possible, and, with complete conviction, I replied: “No.

In a later version, he says he replied that it was possible — perhaps a face-saving maneuver, since by the second time Heisenberg tells the story, he has now started to believe that the reports of the atomic attack against Hiroshima were accurate.

My initial inclination is to think of this as strange idle chatter amongst a group of interned German scientists. A little bit of rumor-swapping, bragging about being in-the-know and being someone worth consulting. But I don’t think Heisenberg just made it up. That’s not really his style, I don’t think, and he repeated it several times over the course of their six month stay at Farm Hall.

Physikalische Blaetter, August 1944

Recently, while looking into some other wartime leaks, I came across an interesting follow-up on this story. The leak in question is a weird one and worth sharing. In August 1944, a German science magazine, the Physikalische Blätter (Physical Newspaper/Gazette/Pages), ran a short, anonymous piece titled “Another Utopia“:1

Transocean Service transmits a report cabled to “Stockholm’s Tidnigen” from London: “In the United States scientific research for a new bomb is underway. The material is uranium, and if the forces bound in this element could be liberated, explosive forces of so far unimagined power could be created. A 5-kilogram bomb could made a hole one kilometer deep and with a radius of 40 kilometers. In a circle of 150 kilometers all buildings were be smashed.”2

That’s a pretty weird thing to just appear in a German magazine, no? To save you the effort: their math on the energy release is way off by any measure — the damage radius described is well over 100 megatons, which is around what you’d get if you combined 5 kg of uranium with 5 kg of anti-matter (a pure E=mc2 conversion), much less if it fissioned with perfect efficiency (which would “only” release 85 kilotons).3 Either they’ve carried a few decimal points incorrectly or they’re just really confused. I suspect the latter.

Was this a “legitimate” leak? That is, did it derive from disclosure of confidential information? It’s hard to tell. The fact that it pinpoints the United States as making an atomic bomb out of uranium seems accurate, but everything else seems to be sketchy and confused. It’s true that the plutonium bomb used only around 6 kg of material… but that almost seems like a coincidence given the rest of what they’re talking about here. I’m inclined to file this under “fantastic atomic energy rumors” which were common even before the discovery of fission.

Werner Heisenberg, later in life

Werner Heisenberg, later in life

Anyway. The interesting bit comes 20 years later, in 1964. Physikalische Blätter was (and is) still around, and they ran a story on their wartime leak story. Much of it is repetitive fluff, a by-the-book (for 1964) accounting of Allied and German nuclear research. But along with this, they did attempt to track down the origin of the leak — with no success. But they did decide, thoughtfully, to try and assess the impact of the leak by surveying a few of the Farm Hall physicists to see whether they were aware of the “Another Utopia” story.

Otto Hahn wrote back that he “knew nothing” of the article at the time, and added that while they knew that there were people abroad probably working on the subject of atomic bombs, and that the stopping of all publications about the subject probably indicated the work was secret, that nonetheless they didn’t suspect that the United States would actually be able to produce such weapons in time for use in the war. He then suggested that the Physikalische Blätter should get in touch with Heisenberg, since he was more plugged into such matters than Hahn.4

And they did get in touch with Heisenberg, whose first response was that he hadn’t seen the article, was surprised to hear about it, suspected it was based on “vague rumors,” but said he would love if they sent him a copy so he could evaluate it further.5 They did this, of course, and his second response was the more interesting one. He said that rumors of this sort occurred repeatedly because of articles related to atomic energy that had already been published, and he did not let such rumors occupy him much during the war. But then Heisenberg wrote (my awkward translation — original German is in the footnotes):

Perhaps I should mention here an exception. In the summer of 1944 (probably early July), an aide of Göring’s came to me with a message from a German representative in Lisbon that there was a pronounced American threat against the German government, that an atomic bomb would be dropped on Dresden in the next six weeks if the government did not immediately sue for peace. The exact conditions of where the message came from were not communicated to me. I was asked by Göring’s adjutant if I thought it was possible that the Americans had already created an atomic bomb. I was understandably made very uncomfortable by this question, because of the large responsibility connected to my answer. I said that I thought it was extremely unlikely, but not impossible, for the Americans to have such a weapon at this time, and I tried to explain that the production of the weapon would in any case require an enormous industrial effort, and that I could not imagine that the Americans had already done it.6

And so the Dresden atomic bomb rumor raises its head again, no less confounding than before! But here we have a little more information on the source: it is supposedly from an agent in Lisbon, Portugal. Which is interesting.

General Groves not amused

General Groves is not amused by spies or leaks

Because as Stan Norris communicated to me when I wrote about German espionage efforts, there was a Nazi double-agent in Lisbon who was assigned to learning about the Manhattan Project. Stan has since sent me a “note to file” that General Groves had written about a meeting he had with the Military Policy Committee on June 21, 1944, where he describes this incident and his response to it. In his notes, Groves wrote the following:

This refers to the German agents who came to this country through Portugal, and the messages that were sent back to Germany in their behalf. These people were picked up as soon as they got into the United States and the messages were framed by me. There was considerable argument by my creeps as to these messages. I overruled them and did not deny that certain work was being done. It was pinpointed at certain universities and certain people, none of whom had anything to do with the project. The amount of the work was minimized, and an attempt to convince the Germans that it was an academic effort and that nothing would come of it. The creeps wanted to say that nothing was being done and that checks at various places had indicated that all potential personnel was being used on other work — I think radar.7

Ah, so now this gets really interesting, right? Because this coincides very well with the timing of Heisenberg’s supposed query — apparently originating in Nazi agents in Portugal — regarding whether Dresden would be atomic bombed! (And no, I don’t know why he calls whomever he is talking to “creeps.”)

Obviously I don’t have the whole story here, but the geographical and chronological proximity is a rather impressive overlap, is it not? Could something have gone wrong, or gotten scrambled, in Groves’ attempt to manipulate one of the few German atomic espionage attempts? I.e., Groves had wanted to suggest that the American program was small and unimportant; somebody instead reported back that it was massive and almost ready to go. It seems not impossible, though this is admittedly scant evidence. Either way, it’s clear that Groves would have been mighty mad to find out this question was being asked of Heisenberg.

But, here’s the twist. Arguably the exaggerated outcome would have been (and in fact was!) as good an outcome as Groves’ intended minimization, if not a better one! Heisenberg looked at the six-weeks-to-an-atomic-Dresden claim and said, no way — that doesn’t make any sense. He came away from the whole thing convinced it was just ridiculous wartime nonsense. If the report he had gotten was, “do you believe that the only people working on nuclear fission are a bunch of no-names, instead of Bethe and Fermi and Oppenheimer and Wheeler and all of those other physics luminaries we know the Americans have?,” might that not have raised his suspicions even more?

Of course, that doesn’t explain where Dresden, specifically, would have come into the picture. So there’s still something missing here. And it should be noted that Lisbon was a notorious hub of espionage activity for both sides during the war — so it isn’t necessarily the same guy. So some sobriety intrudes.

Dresden after the firebombing, 1945

Dresden after the firebombing, 1945

Lastly, is it possible the Dresden threat could have been real? The Physikalische Blätter story got picked up by the Washington Post, and they got in touch with Richard G. Hewlett, the Atomic Energy Commission’s official historian. He thought Heisenberg’s story was pretty nuts: “I can’t possibly believe there was an actual threat from the U.S. Government.”8 This was, obviously, because the US was still a year away from an atomic bomb at the time, and the idea of it being some kind of legitimate, diplomatic threat seems pretty out of character. Though do remember that Roosevelt asked Groves about using the bomb against Germany in December 1944 — so maybe, somewhere, this kind of idea was kicking around inside the heads of some people who knew about the Manhattan Project work but didn’t know how close it was to completion — maybe even someone who was working some kind of diplomatic/espionage backchannel. I don’t know.

As it was, Dresden was of course catastrophically attacked. Over the course of three days in February 1945, some 1,250 Allied heavy bombers pounded the city with incendiaries and high explosives, killing well over 20,000 people and burning the heart out of a city that until that point had been spared the horrors of area bombing. Could Dresden have been kept “pristine” on the theory that it might have been a good atomic bombing target, in the same way that Hiroshima, Nagasaki, Kokura, and Niigata had been? The Physikalische Blätter speculated that maybe this was the case, though there is no evidence that supports this conclusion.9 I doubt it, personally — the selection of Dresden as a target has its own trajectory that seems independent of any possible atomic narrative, and the idea that it would have been selected as a possible atomic bomb target as early as the summer of 1944 seems rather far-fetched. It should be noted, as well, that the narrative about the atomic bomb in mid-1960s Germany was very much tinged by the Cold War context; it was a common thread of discussion in both the West and the East that the United States would be willing to throw Germany under the bus if it came to a real confrontation with the Soviets.

Still, it’s an interesting constellation of stories: the leak, Heisenberg’s query, and Groves’ attempt at misinformation. If Groves’ misinformation attempt was really did result in the query to Heisenberg, what tremendous irony would abound. Ironic that Groves’ attempt to minimize the effort would result in a exaggerated interpretation; irony that the exaggerated interpretation would lead to total dismissal by the expert.

Notes
  1. Noch eine Utopie,” Physikalische Blätter 1, No. 8 (1944), 118. I was surprised to find all of PB online and without a paywall. This particular article is appended to a longer report on “Science and War.” []
  2. “Transozean-Innendienst verbreitet eine Nachricht, die sich “Stockholms Tidningen” aus London melden läßt: “In den Vereinigten Staaten werden wissenschaftliche Versuche mit einer neuen Bombe ausgeführt. Als Material dient Uran, und wenn die gebundenen Kräfte in diesem Element frei würden, dann könnten Sprengwirkungen· von bisher nicht geahnter Kraft erzeugt werden. Eine 5-kg-Bombe könnte dann ein Loch von 1 km Tiefe und 40 km Radius hervorbringen. In einem Umkreis von 150 km würden alle festen Gebäude in Trümmer gehen.” []
  3. The rule of thumb is that the completely fissioning of a kilogram of fissile material produces about 17 kilotons of yield. []
  4. “Ich wußte gar nichts von dem Inhalt des Artikels im Augustheft 1944 der Physikalischen Blätter, und so möchte ich daraus schließen, daß er mir auch damals nicht bekannt war. Wir alle waren natürlich während des Krieges der Meinung, daß man im Ausland, vor allem in Amerika, wohl an einer Herstellung von Atombomben arbeiten wird, denn es wurden ja auch in Deutschland Vorversuche darüber gemacht mit dem Versuch der Aufstellung eines Atomreaktors. Und da nach Kriegsanfang alle Publikationen aus dem Gebiete aufhörten, schlossen wir natürlich, daß im Ausland geheime Arbeiten gemacht würden. Andererseits glaubte keiner von uns, daß während der Kriegszeit eine Atombombe fertiggestellt werden könnte. Ich erinnere mich an das Erstaunen, das wir alle hatten, als wir von der Bombe im August 1945 in englischer Gefangenschaft erfuhren. Da Prof. Heisenberg der Vorsitzende des sogen. Uran-Vereins war, also die Arbeiten zur Herstellung eines Kernreaktors geleitet hat, ist wohl Herr Heisenberg die beste Quelle, zu erfahren, ob jemand von uns die Mitteilung in den Phys. Blättern kennt.” Otto Hahn, quoted in E. Brüche, “Was wußte man 1943/44 in Deutschland von der Atombombe?Physikalische Blätter 20, No. 5 (1964), 220-225, on 222. []
  5. “Sie schreiben davon, daß in den Phys. Blättern bereits 1944 eine Notiz über die amerikanischen Versuche mit Atombomben erschienen sei. Dies ist mir völlig neu, aber zugleich interessant und unbegreiflich; denn die ersten amerikanischen Atombombenversuche haben ja bekanntlich im Frühjahr 1945 stattgefunden. Es kann sich also eigentlich nur um ziemlich vage Vermutungen gehandelt haben. Ich wäre Ihnen sehr dankbar, wenn Sie mir eine Kopie jenes Artikels in den Phys. Blättern zukommen lassen könnten; dann kann ich besser beurteilen, ob ich diesen Artikel jemals gesehen habe und wie ich darauf reagiert habe.” Werner Heisenberg, quoted in E. Brüche, “Was wußte man 1943/44 in Deutschland von der Atombombe?” Physikalische Blätter 20, No. 5 (1964), 220-225, on 222. []
  6. “An die von Ihnen erwähnte Notiz in den Phys. Blättern aus dem Jahr 1944 konnte ich mich nicht mehr erinnern, aber Gerüchte dieser Art sind – schon aufgrund des Flüggeschen Artikels in den “Naturwissenschaften” – immer wieder aufgetreten und haben mich daher nicht allzu sehr beschäftigt. Vielleicht sollte ich hier eine Ausnahme erwähnen. Im Sommer 1944 (wahrscheinlich Anfang Juli) kam einmal der Adjutant von Göring zu mir mit der Mitteilung, es sei über die deutsche Vertretung in Lissabon eine amerikanische Drohung gegen die deutsche Regierung ausgesprochen worden, es werde innerhalb der nächsten sechs Wochen eine Atombombe über Dresden abgeworfen werden, wenn die Regierung nicht in irgendeiner Art um Frieden bäte. über den genauen Inhalt der Bedingungen wurde mir nichts mitgeteilt. Ich wurde von dem Adjutanten Görings gefragt, ob ich es für möglich hielte, daß die Amerikaner bereits über eine Atombombe verfügten. Mir war diese Frage begreiflicherweise sehr unangenehm, weil mit der Antwort auf jeden Fall eine große Verantwortung verbunden war. Ich habe dann gesagt, daß ich es zwar für außerordentlich unwahrscheinlich, aber nicht für völlig unmöglich hielte, daß die Amerikaner zu diesem Zeitpunkt über eine solche Waffe verfügten, und habe versucht zu erklären, daß die Herstellung der Waffe auf jeden Fall einen enormen industriellen Aufwand erfordern müßte, von dem ich mir nicht denken könnte, daß die Amerikaner ihn schon geleistet hätten.” Ibid. An article on uranium fission by Siegfried Flügge appeared in Die Naturwissenschaften in June 1939; Heisenberg cites this as the reason for all of the speculation. Flügge himself was asked about the “Another Utopia” article as well and he responded with a diatribe about how nobody credits him for anything. []
  7. Leslie Groves, Notes on the Military Policy Committee of June 21, 1944 (undated, but prior to 1964), Leslie R. Groves Papers, National Archives and Records Administration, RG 200, Entry 7530M, Box 4, “Working Papers.” Courtesy of Robert S. Norris. []
  8. Howard Simons, “Were We Vulnerable: Swedish Report in World War II Tipped U.S. A-Bomb Hand,” Washington Post (27 December 1964), E3. Simons’ story butchers many of the facts, including getting the nationality of Physikalische Blätter wrong (which PB took issue with in its reprinting of it), and even misspells Hewlett’s name. []
  9. “Dresden – Schicksal und Warnung,” Physikalische Blätter 21, no. 4 (1965), 196. []