Chapter 9


"Bagge in Berlin and Clusius and Dickel in Munich developed isotope
eparation methods but achieved little practical success. They never obtained
enough U235 to make the proper measurements and certainly too little for a bomb."

David Cassidy

"Introduction," Hitler's Uranium Club 1

The transcripts of the German scientists interred at Farm Hall seem like a microcosm of Nazi German culture itself, simultaneously charming and paranoid, moralizing and utterly amoral, suffused with brilliant subtlety and ham-fisted bluntness. In view of the thesis that has been examined throughout the previous pages, the Farm Hall transcripts also reveal an equal schizophrenic on the part of commentators ever since their declassification in the early 1990s by the British government.

Consider for example the following remark by Jeremy Bernstein with regard to Samuel Goudsmit's "ALSOS" mission to Germany at the end of the was,

"As the mission progressed, and the Alsos team learned more and more about the paucity of the German program, the concern focused on not letting the Russians get at the Germans and so glean 'any major bomb secrets.'"2

If the German bomb program was in a state characterized as "paucity," and if there were fundamental "problems" in Heisenberg's understanding of nuclear fission and bomb physics - as there indeed were - then why the concern at all? But then early on in the transcripts an exchange between Heisenberg, Diebner, and Korsching occurs, in which the three German scientists discuss the possibility that they may have been viewed by the Allies and Soviets at Potsdam as war booty.

1 David Cassidy, "Introduction," in Jeremy Bernstein, ed., Hitler's Uranium Club: The Secret Recordings at Farm Hall, Second Edition, (new York: Copernicus, 2001), p. xxix.

2 Bernstein, op. cit, p. 47.

Barnstein then comments,

"presumably Heisenberg is worried here about being taken to task in German for failing to build a bomb. The notion that these ten German scientists would be discussed at the Potsdam Conference borders on the ludicrous."3

If so ludicrous, then why inter them for months, secretly record their conversations and transcribe them, and then keep them classified until the early 1990s? Clearly it would seem that something more is going on at Farm Hall that either eludes commentators, or that they are simply ignoring. The conversations proceeds among the ten scientists, with one concern (prior to the announcement of the a-bombing of Hiroshima) being how to continue with their "work", totally oblivious to the fact that others had indeed carried on their "work" to brilliant conclusion.4

The schizophrenia grows whenever the subject of isotope separation comes up in conversation. In the epigraph that began this chapter, reference is made to the Clusius tube "thermal diffusion" method perfected by Clusius and Dickel:

"Bagge in Berlin and Clusius and Dickel in Munich developed isotope separation methods but achieved little practical success. They never obtained enough U235 to make the proper measurements and certainly too little for a bomb."5

However, in the transcripts themselves, Heisenberg remarks that one reason he and his fellow scientists were interred was that the Allies did not "want us to pass on our knowledge to other people."6 However it is the editorial comment of this remark that really intrigues; the Germans, notes Bernstein, would have had little knowledge "that would have been of any use to the Allies," but a great deal of expertise that they would have wanted to keep from the hands of other powers such as France and Russia. Then follows another remark concerning Harteck's "ultra-centrifuge" technology, which "would have been an extraordinarily useful thing for any country to possess."7

3 Bernstein, op. cit, p. 81, n. 16.

4 Ibid., pp. 82-84.

5 Ibid., Cassidy, "Introduction," p. xxix.

6 Ibid., p. 91, the conversation is between Heisenberg, Von Weizsacker, Wirtz, Harteck and Diebner on July 18, 1945.

7 Ibid., p. 91, n. 7.

Indeed, this was a technology that even the US and UK had not brought to such an advanced state of perfection.

And then, on July 26, 1945, a remark is made by Otto Hahn that only increases the mystery:

"I read an article in the Picture Post about the uranium bomb; it said that the newspapers had mentioned that such a bomb was being made in Germany. Now you can understand that we are being 'detained' because we are such men."8

The editorial comment only increases the problem:

"This was before the bomb was used on Japan, when its existence was kept in strict secrecy!"9

Had Hahn unwittingly let the cat out of the box? It is an odd thing for a scientist of Hahn's stature to say, especially since, as we have seen, there were a wealth of "indications" of the size of the German project that appeared in short articles in the Allied press both during and after the war.

Then on July 21, 1945, the handsome and cynical Horst Korsching, discussing the prospects for making a living with Diebner and Bagge, offers a curious observation:

BAGGE: For the sake of the money, I should like to work on the uranium engine; on the other hand, I should like to work on cosmic rays. I feel like Diebner about this.

KORSCHING: Would you both like to construct a uranium engine?

DIEBNER: This is the chance to earn a living.

KORSCHING: Every layman can see that these ideas are exceedingly important. Hence there won't be any money in it. You only make money on ideas which have escaped the general public. If you invent something like artificial rubies for the watch making industry, you will make more money than with the uranium engine.10

8 Bernstein, op. cit., p. 94.
9 Ibid., n. 19.
10 Ibid., p. 99.

Artificial rubies? Of course, such things were used in watch making before the invention of quartz movement. But in 1945, the idea was fantastic. Of course, by the time of the declassification of these transcripts, the world's first laser, which did in fact use an artificial ruby as the main component of the lasing optical cavity, was history, having been invented in 1961. But in July of 1945 the idea was more than a little ahead of its time. Is this another possible, though slight, indication that something else was going on inside Nazi Germany?

Later in the conversation, Korsching expresses his desire to return to Hechingen to collect his telescope, lenses and prisms, an indication that he was perhaps involved in optical as well as nuclear research. But then, another curious statement from Korsching:

Of course it would be an idea to go to the Argentine with two people and say: "Here we are, we know how to do this and that; we have a good method for the separation of isotopes, we do not need to produce heavy water." Somehow in this fashion we have to do it. It would not come to anything if you collaborated with Heisenberg on a uranium engine. They did not even bring along the small fry to this place, that is how outsiders judge the work.11

If the thesis presented thus far is true, and there was a very secretive SS bomb project and if the Heisenberg represented a false front "sham" project being deliberately shut out of the loop by the SS and maintained for Allied consumption, then indeed there may be other motivations for the internment of the German scientists than are commonly supposed. If, for example, General Patton's Third Army troops did indeed find and discover components and scientists from the SS project, then it would have been crucial to ascertain whether or not the "big fish" - to paraphrase Korsching's rather self-important view of the scientists at Farm Hall - had had any knowledge of these SS projects.

Then, in the transcripts of conversations from August 1-6, 1945, Dr. Kurt Diebner briefly mentions a fact that carries great significance in the light of what we have discovered of the German atom bomb project and the SS Sonderkommando underground factories in the Harz Mountains in Thuringia. Diebner mentions very briefly that his supply of radium was obtained "from the Harz."12

11 Bernstein, op. cit., p. 100.
12 Ibid.,p. 111.

Bernstein's comment at this juncture is of a brevity huge with omissions: "A mountain range in central Germany." Bernstein does not have anything more to say about the subject. Is he ignorant of the claims being uncovered by contemporary German researchers? Or does the omission of mention stem from some other motivation?

In any case, the tenor and mood of the scientists quickly changes when they learn of the atom bomb dropped on Hiroshima. The first reactions, recorded by the British microphones, occurs between Hahn and Wirtz:

HAHN: They can only have done that if they have uranium isotope separation.

WIRTZ: They have it too.14

A discussion quickly ensues between all the German scientists, and again it is Diebner who makes a short statement pregnant with significance: "We always thought we would need two years for one bomb."15 Moreover, Bernstein at this point betrays a hesitation and uncertainty unusual in his otherwise straightforward commentaries and annotations whose aim is clearly to maintain the Allied Legend:

"I am not sure whom Diebner includes in his 'we' here or on what his estimate is based. But his use of the word 'bomb' is unchallenged by the others."16

14 Bernstein, op. cit., p. 115, emphasis added.
15 Ibid., p. 117.
16 Ibid., p. 118.

Who indeed were the people that Diebner referred to when he said "we"? Bernstein appears not to know, but given that Diebner has earlier referred to his supply of radium "in the Harz", we may rationally speculate that Diebner was referring obliquely, and no doubt intentionally so, to his colleagues in the SS run program.

Then follows a short, but astonishing, exchange between Hahn, Weizsacker, Harteck, Wirtz, and Diebner:

HAHN: I think it's absolutely impossible to produce one ton of uranium 235 by separating isotopes. 17

WEIZSACKER: What do you do with these centrifuges?

HARTECK: You can never get pure "235" with the centrifuge. But I don't believe that it can be done with the centrifuge.

WIRTZ: No certainly not.

HAHN: Yes, but they could do it with mass spectrographs. Ewald has some patent.18

DIEBNER: There is also a photochemical process. 19

17 This comment, in the light of what has already been learned about the size of the German enrichment program, can mean only one of two things: (1) Hahn is deliberately lying here, to deflect his on possible involvement in the program; or (2) he is telling the truth, and knows nothing about it. Of the two, the latter is the much more likely.

18 Again, Hahn has pointed the way clearly to Baron Manfred Von Ardenne's cyclotron modifications. Thus, the German scientists knew how to do it, and as is therefore extremely likely, the SS also knew which was the best method. Hence, the extraordinary power consumption at Auschwitz points, as does the most efficient method itself, to Von Ardenne's method as the method most likely used there and elsewhere to separate isotope.

19 Bernstein, op. cit., p. 118.

Now let us put all this in context, for this little exchange is an indication that a possible "farce" is being played out at Farm Hall, not only by the interred German scientists, but also possibly by the declassification of the transcripts themselves. What do I mean by this? Note that the transcripts are declassified by the British after the German reunification in 1989, an oblique admission, perhaps, that there was no more purpose in maintaining whatever secrets they still held, since there would now be other sources available to tell the story that had been long suppressed: that the Nazis had been either perilously close to, or had actually acquired the atom bomb before the Allies.

First, note in the above exchange that Otto Hahn, whose remarks began this chapter, has now changed his mind. His earlier remarks mention isotope separation as the means to a bomb. Now, he has reversed himself, and all on the same day. But then comes Weizsacker's remark: What else would one used centrifuges for?20

This is countered by remarks from the inventor himself, Paul Harteck, who maintained one cannot obtain "pure 235" via that process. Wirtz then chimes in with agreement, and then Hahn, ever the radio-chemist, reverses himself again, within a matter of minutes, by coming to the obvious conclusion from a scientific and engineering standpoint: the best way to obtain "pure" U235 was via mass spectrography.

But then comes the bombshell. Diebner, who clearly has some connection to Kammler's SS "think tank" special projects empire in the Harz mountains, alludes to an unknown "photochemical" process for isotope separation and enrichment. Even Bernstein admits that whatever Diebner meant by this remark is "unclear"21 In all likelihood, it is unclear, because it remains classified, somewhere, by someone. And that should give us pause, for it means that the Kammlerstab may have found a method of isotope separation and enrichment that remains otherwise unknown to this day!

Shortly after this revealing little exchange, Wirtz then offers another solution: "I would bet," he says, "that it is separation by diffusion with recycling."22

20 As we shall discover, there may well have been another use to which this, or a modified, technology had been put by the SS.

21 Bernstein, op. cit, p. 117, n. 24.

22 Ibid., p. 118.

Wirtz is clearly proposing that separation was a multi-staged process, with the result of one pass through the separation process then being used as feedstock for another pass for enrichment to greater purity, and the process being repeated until the desired grade of purity - weapons grade - was obtained. The diffusion process mentioned in this context is vague, for there were at least two methods known to the Germans, the Allies, and the Japanese under the name of "diffusion".

One method, cited by Bernstein as the explanation of Wirtz's remarks, is the manufacture of uranium gas, and forcing it under pressure through sinterized metal. Sinterization simply means that a metal contains billions of micro-pores or holes of specific and tiny size, through which the atoms of different isotopes diffuse at slightly different rates of speed.

"The original estimate was that 5,00 of these barriers would be needed for nearly complete separation, as opposed to 22,000 centrifuges."21

The other process was thermal diffusion that was already examined more closely in chapter 7.

The thermal diffusion method is mentioned briefly in the published Farm Hall transcripts during the conversations of the German scientists on the day of the Hiroshima bombing by Weizsacker.24 Bernstein notes of this method that it was being tried by Korsching, and that it consisted of a "glass tube and heating coil to separate isotopes. It never worked well for uranium."25 But what Bernstein has described is the original Clusius-Dickel tube for thermal diffusion, a process that was not efficient, as Bernstein correctly indicates. However, a different method of Clusius tubes was described by Wilcox in reference to the Japanese program:

What the Nishina group finally did settle on was a process called thermal diffusion. This had been one of the first isotope separation processes devised. Bu until it was perfected by two German scientists, Klaus Clusius and Gerhard Dickel, in 1938, it had not been practical. Stated simply, thermal diffusion relied on the fact that light gas moves toward heat. Clusius and Dickel constructed a simple device consisting chiefly of two metal tubes placed one inside the other. The inner tube was heated; the outer tube was cooled.

When the apparatus was turned on, the lighter U-235 moved to the heat wall; the U-238, to the cold wall. Convex currents created by this movement sent the U-235 upward; the U-238 downward. The result was something like a heated house in winter; hot air rising, cold air staying at the bottom. At a certain point the U-235 at the top could be collected, and new gas pumped in. It was a simple and rapid way to get relatively large concentrations of U-235.26

23 Bernstein, op. cit., p. 119, n. 28.
24 Ibid., p. 199.
25 Ibid., p. 83, n. 27.
26 Robert K. Wilcox, Japan's Secret War, p. 95, emphasis added.

And with repeated passes through a series of such vessels, purity would be increased. In any case, there is some discrepancy in the method as described by Bernstein, and that by Wilcox. Perhaps the latter described a modification made to the original method, with extremes of heat and cold being applied.

Harteck, Wirtz, and Heisenberg then continue the subject to isotope separation and enrichment a little further on:

HARTECK: They have managed it with mass spectrographs on a large scale or else they have been successful with a photochemical process.

WIRTZ: Well I would say photochemistry or diffusion, ordinary diffusion. They irradiate it with a particular wavelength (all talking together).

At this juncture, Bernstein again observes that "it is not clear" what this photochemical process is.27 In any case, whatever the process was, Wirtz's mention of it and of irradiation with a particular "wavelength" appears to have provoked a burst of conversation from the other scientists. Were they intentionally trying to drown him out and mask his statements so as not to be recorded? We will never know. But in any case, the conversation continues:

HARTECK: Or using mass spectrographs in enormous quantities. It is perhaps possible for a mass spectrograph to make 1 milligram in one day - say of "235." They could make quite a cheap mass spectrograph, which, in very large quantities, might cost a hundred dollars. You could do it with 100,000 mass spectrographs.

Again, Bernstein's comment is suggestive: "This is essentially what the Allies did."28

27 Bernstein, op. cit., p. 120, n. 37.

28 Ibid., p. 120, n. 38.

But it is also, as we have seen, very probably what the Germans did at the "Buna plant" at Auschwitz and later, in the large underground factories run by Kammler's SS Sonderkommando. The Farm Hall scientists, as to be expected, seemed totally oblivious to this program, but have worked out the basic facts for themselves.

HEISENBERG: Yes, of course, if you do it like that, and they seem to have worked on that scale, 180,000 people were working on it.

HARTECK: Which is 100 times more than we had.29

It may have been 100 times more than Harteck or any of the high profile scientists interred at Farm Hall had at their disposal, but it was certainly not a number beyond the SS, with its hundreds of thousands of concentration camp slave laborers. Hahn later reinforces the pathetic plight of the "Heisenberg group" by adding "Of course, we were unable to work on that scale."30 Such facts and methods would doubtless have been known to the Kammlerstab, and doubtless he would have pursued them with his customary "focus."

Harteck then corroborated this view in a statement regarding the Clusius process, and his numbers reveal the dangerous potential for isotope separation and enrichment that lay within Nazi Germany's capabilities if worked on a similarly large scale as the Manhattan Project:

If it is a fact that an explosive can be produced either by means of the mass spectrograph - we would never have done it as we could never have employed 56,000 workmen. For instance, when we considered the Clusius-Linde business combined with our exchange cycle we would have needed to employ 50 workmen continuously in order to produce two tons a year. If we wanted to make ten tons we would have had to employ 250 men. We couldn't do that.31

29 Ibid., p. 120

30 Ibid., p. 121.

31 Ibid.

For Harteck and the other Farm Hall scientists, the problem was not means or methods, it was simply a labor shortage, a shortage the SS was not experiencing. Later, Harteck is even more specific:

Considering the figures involved I think it must have been mass spectrographs. If they had had some other good method they wouldn't have needed to spend so much. One wouldn't have needed so many men.

Korsching responds, and a small debate ensues, in which a sensitive topic is barely touched upon by Harteck, and Bernstein's editorial comment becomes either an exercise in ignorance, or deliberate omission:

KORSCHING: It was never done with spectrographs.

HEISENBERG: I must say I think your theory is right and that is spectrographs.

WIRTZ: I am prepared to bet that it isn't.

HEISENBERG: What would one want 60,000 men for?

KORSCHING: You try and vaporize one ton of uranium.

HARTECK: You only need ten men for that. I was amazed at what saw at I.G. 32

32 Bernstein, op. cit, p. 122, emphasis added.

Bernstein's only comment here is to note the obvious, that "I.G." means "I.G. Farben," nothing else is said. Either Bernstein is unaware of the Farben "Buna plant" and its mysterious properties of consuming more electricity than Berlin and producing no Buna, or he has intentionally omitted any further clarification of Harteck's remark. The Allied Legend, in so far as Bernstein is concerned, is intact.

For his part however, Harteck is either clearly implying that he saw some large scale effort underway by I.G. Farben, employed tens of thousands of workers, or his remarks might also be construed to indicate that the Germans had discovered a method to make the process less labor intensive. In any case, I know of no other Farben facility in Germany at the time that was known to be working on enrichment.

The only facility with the requisite "enrichment facility" signature is the one at Auschwitz, and this means that Harteck may have seen not only a project as large as that at Oak Ridge, Tennessee, but one that was either more efficient - as we know Von Ardenne's mass spectrographs to be - than its American counterpart, as well as one less reliant on skilled labor, for the labor at Auschwitz, was "inexhaustible", and unfortunately, suspendable.

In any case, if all this is so, then it is a strong indicator that Harteck's and possibly some or all of the other interred scientists' remarks in the Farm Hall transcripts are careful stage-acting, a script that reveals just enough engineering savvy to indicate that the scientists knew at least the broad outlines of how an atom bomb could be achieved without a nuclear reactor (or "uranium engine" as they called it), and yet interlarded with just enough ignorance on specifics to indicate either that they were not involved at the highest levels, or that they were deliberately dissembling.

In Harteck's case, at least, we must opt for deliberate dissembling to a certain degree, for what he saw - if he was not completely involved with it - was a vast enrichment program proceeding on the emaciated backs of concentration camp laborers.

As if this were not enough, Weizsacker later corroborates the broad outlines of the top secret SS program we have outlined previously:

WEIZSACKER: If you had wanted to make a bomb we would probably have concentrated more of the separation of isotopes and less on heavy water.... If we had started this business soon enough we could have got somewhere. If they were able to complete it in the summer of 1945, we might have had the luck to complete it in the winter 1944-45.33

33 Bernstein, op. cit., p. 123.

Note that he not only corroborates the broad time frame we have already found for the alleged German atom bomb test at Rugen, but more importantly, his statement comes after Harteck's clear allusion to the existence of just such a program in Nazi Germany.

A little later, the British military intelligence summary of the conversation that ensues interjects the following cryptic summary of comments made by Walter Gerlach, without any further commentary:

"Gerlach goes on to explain that the Nazi party seemed to think that they were working on a bomb and relates how the Party people in Munich were going round from house to house on the 27th or 28th of April last telling everyone that the atomic bomb would be used the following day."34

Bernstein's editorial note reflects his confusion, and confirms that he is in all likelihood not familiar with the allegations of the tests at Rugen and Ohrdruf: "It is not clear who has supposed to be using this weapon and against whom."35

In any case, so far from contradicting the possibility of a secret enrichment and bomb program, however, in the main the Farm Hall scientists seem to corroborate it.

Finally, Harteck again must have stunned his British captors with a remark made near the end of the transcript for August 6, 1945:

HARTECK: The multiplication factor with "235" is 2.8, and when one collides with the other how long is the path until it happens? 4 centimeters, Rx is the radius. Then you have to multiply that by the mean free path and divide it by the square root of the multiplication factor. That should be 3.2. Rx is about 14 centimeters, the weight is200 kilograms; then it explodes.36

Even Bernstein cannot ignore this, and his comment indicates the there is a "possible something" lurking behind Harteck's figures:

This apparently off-hand calculation of the critical mass by Harteck which does lead to a sensible answer, unlike Heisenberg's shows some evidence that he had done this problem before. It is difficult to believe that he would have known, for example, that the critical radius involved the inverse square root of the multiplication factor if he had not thought about it. How Harteck got the number 2.8 for the multiplication factor is unclear.

During the war the Los Alamos people, who certainly knew a lot more than he did, used 2.2. Only after the war was the number increase to 2.52 as the measurements became better. Perhaps it was Harteck who supplied the German Army Ordnance report of January 1942 with its numbers in the scientists' attempts to interest the Army in continuing support of bomb research.37

34 Ibid., p. 126.
35 Ibid., n. 85.
36 Ibid., p. 133.
37 Ibid., n. 121.

Perhaps Harteck had "run the numbers" before. But there is another possibility.

Perhaps, on his visit to "I.G." that he alluded to earlier, someone had shown Harteck the numbers. In this regard it is perhaps significant that of all the Farm Hall scientists, his comments most consistently point to the acknowledgment of a feasible method that, with large enough scale, could lead to sufficient quantities of fissile weapons grade uranium. And it is significant too that the transcripts reveal a variety of methods known and available to the Germans that, used in sufficient numbers and with a sufficient labor pool, could have done exactly that.

Harteck's comments point in the consistent and general direction of Manfred Von Ardenne, Fritz Houtermans, and the rubberless "Buna facility" of I.G. Farben at Auschwitz. Like the Farben directors themselves in the dock at Nuremberg, Harteck is perhaps, in his own subtle way, trying to set the record straight. These facts and associated speculations also perhaps explain why, after so many years, the Farm Hall transcripts were finally declassified, for they do not, in the final analysis, serve the Allied Legend well.

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