|Interviewer: Robin Hughes
Recorded: January 21, 1992
This is a transcript of the complete original interview conducted for the Australian Biography project. Each transcript page covers one videotape (approximately 35 minutes). There is also QuickTime video of the full interview available. To play the video, click on the icon in the right hand column. In addition, each question in the transcript is linked to the video. Clicking on a question will play the video from that point. (Help with this feature.) Optionally, you can download the video file for offline viewing (approx. 10MB).
The interview has been left it in its original state so that you can get a sense of how the conversation developed. The repetition of some questions, or a question followed by another question, is often due to the end of a particular tape or some other interruption, and has been indicated at the appropriate place in the text. There has been minimal tidying up of the text so that the flavour of the encounter has been kept.
In the course of your work, leading up to and through the war years, you'd developed this great excited interest in what was happening in the atom and the way in which you might be able to discover more about that. Did it never, during that time, occur to you where it might all be leading?
Ah - I'm not quite sure that I understand what you mean. You see my work in nuclear physics began in the 1930s, long before war broke out, and it wasn't during the war that I developed this interest. It was only the fact that during the war we thought for the first time of the possibility [of] nuclear weapons. And that was the change, a rather horrifying thought, but still one that we had to think about because we knew that the Hitler regime was attempting to develop nuclear weapons, because the fission process made the chain process practicable, and the Germans who from Secret Service information we knew were working hard on the project. So that's the only reason that we took it seriously.
Well perhaps I could go back a step and ask the question slightly differently. During the '30s when you were working on - at the Cavendish and you were excited about what was happening, could you describe what it was that intrigued you, that engaged you?
Well here one was discovering something about the most minute thing that we could think of in the universe. If one takes an ordinary atom, of course you can't see it. There's no way of seeing it - you've got to examine it by indirect method using x-rays and so on, and the sort of light that it emits to give you information about its structure and so on. It's - but that only gives you information about the outside of the atom, the electrons around the atom which produce the light that is emitted when an atom is excited in some way, like in a fluorescent lamp for instance, but we were interested in the inside of the atom. Now Rutherford had discovered that the atom was like a solar system that had a little central sun, or nucleus as we called it, in the year 1911, when he was working in Manchester, and it was the structure of this tiny little thing, so small that it's one over ten with twenty-four noughts after it in centimetres in diameter; so that you can see how incredibly small it is. And the only way in which you could examine it was in indirect method, that's to say by a sort of hitting it and seeing what happened. And the chances of hitting it, because it was so small and minute, so you had to fire tens of millions of bullets as it were at it, in order to make a collision with it. It was described by somebody once in these words that might interest you: supposing you were in a small boat, you were rowing across the sea, and you had nothing but oh, the oars that were in the boat and yourself, and you came across a small island, and this island had around it a high wall, and this high wall was smooth and it was too high for you to look over, and you had no equipment that allowed you to climb it in any way. How could you discover whether the island was inhabited and what sort of inhabitants there were on the island without ever seeing them? The answer, of course, is what you'd do would ... you'd pick up some stones off the seashore, and you'd throw them over the wall. If there are intelligent beings there, sooner or later they'd be provoked into throwing them back again, and from the velocity, the energy with which they came, and you could determine something about the strength of the people who lived on the island, and from the direction in which they came. Supposing they were thrown directly back in the direction that they'd arrived, you'd know that you had reasonably intelligently people on the island, and so you can elaborate this into getting a pretty good picture of the inhabitants on the island without ever having seen them. That's what we do with the nucleus of the atom. We fire visitors as it were into the interior of this atom, which is - takes the - you've got to as I said fire tens of millions of them, in the chance of one sometimes hitting and penetrating inside the nucleus and then look at what happens, what sort of particles come out, what are results of the disintegration, the breakdown of the nucleus, or what used to be called the splitting of the atom.
So in order to understand it, you had to attack it.
That's right. It's the only way to - and during these processes of understanding it, it was found that one was creating all the time new sorts of atoms that were unknown on earth. Things like sodium for instance, which is the material in common salt - sodium chloride: sodium is a metal, a soft metal, and it - rather interesting metal, but it is just a normal material, has no oh, just chemical properties, normal properties. It's very ubiquitous, it occurs in the sea you see as the main component of the salts in the sea and so on. But when you hit it with one of these particles, sometimes you knock a bit out of it and the remaining part is radioactive just like radium. So that one can create radioactive species of all the atoms in the universe by hitting them with the right bullets and knocking bits out of them that leave a strange atom that's not a normal constituent of the universe, so it goes back to being a normal constituent by throwing out a bit of itself, until it's the right sort of shape and size to fit.
So in a way you were not only discovering things, but you were creating things, you were playing God in a way weren't you?
That's right. That's right to a large extent.
So was that what you really enjoyed about it?
Oh yes, it was this finding new things, and I talked last time about our discovery of hydrogen of mass 3 and helium of mass 3 in that way, and hydrogen is a stable substance, or pretty stable, it lasts for - it's not a permanent constituent of the - but it's got a pretty long life. The helium on ... is perfectly stable, and the hydrogen changes into helium of mass 3 over a period of time. That's a stable sort of species, that we found does occur in nature to a very, very small extent. It can be detected on the sun for instance, from the light that it gives out.
So you were excited by this, you had a sense of power because you were able to ...
No, no, no. There's no sense of power whatever. This is - this is an ill-conceived idea. One had a feeling that - that one was understanding. That one was coming to have knowledge of how matter was built up, of how the - and then beginning to have ideas about how it all began, how creation took place, and how these atoms, under conditions of very high temperature and pressure, could change into one another. One could build up heavier atoms from the original hydrogen-only atmosphere. It's this concept, this idea that one begins to understand and have some sort of knowledge that it is exciting, not a question of command or of any sort of power that one possessed.
So that's never really been a factor in what you're doing.
No, no, no. In the year 1916, Rutherford, giving a lecture in London in the middle of the First World War, said that - he pointed out to his audience, rather, that there were big energies associated with this radioactive processes that he was investigating. The properties of re-uranium and its products,and that these had to be measured unlike chemical processes which measured in one or less electron volt of energy we ... that is a unit we use in science for measuring the energies of these particles. These particles that are produced from radium had energies of six to ten million electron volts, and he said in the course of this lecture that some of his colleagues thought that it'd be a good idea to find a way of producing radioactivity of this sort artificially so that one would then have enormous sources of power. And he ended up by saying, 'I hope it never happens in my lifetime or some bloody fool might blow the world to bits'. He was just as aware even then in 1916 of what the energy that was locked up inside the nucleus as - although people have accused him of being not in favour of nuclear power and nuclear energy, the reason he always expressed disquiet about it was that he was fearful of the consequences.
So that when war broke out, when did you first become aware of the value that nuclear energy would have in the war effort?
Well I explained that last time I think in some detail, that we knew that the Germans were on to it, that how they - a very famous physicist, Heisenberg was in charge of the work. A man who was fully capable of thinking through the whole process. Heisenberg is the author of the so-called 'uncertainty principal' which is talked about so much, has been written about and so on. So he was an adversary of the first class, and so one couldn't neglect the fact that Hitler might get nuclear weapons, and that was the reason that in Britain we started to do work, and I told the story last time, of the way in which it took place in my laboratory.
I was thinking that one of the first things you were asked to do when war broke out was to go away, and you've told us about how you went away and worked on radar, and then ... But I was wondering from within your own knowledge and your own understanding, when war broke out did you immediately think - before it was brought more directly to your attention - did you immediately think this nuclear capability will play a part in this war, or did it take ...
(interrupting) No it - we did set up a committee of people who were interested in it. A committee that went by various names finally it was called the MAUDE Committee and then the Tube Alloys Committee, in order to disguise what it was thinking about. And it considered all the evidence in favour of the possibility of a chain reaction that would produce a large explosion, and it all seemed at the beginning so distant, until the series of incidents that I remarked upon last time with Peierls and Frisch producing this seminal paper, which woke us up to the fact that it was a real possibility.
Given that you were in a situation where you were unsure of what the outcome would be, and remembering that Rutherford had made this comment about it long ago, did that occur to you then, when you started working and thinking about it that it may be leading beyond where you were all wanting it to go?
Yes, yes, very much so, and very many of the people who were associated with it were very worried about it, including Chadwick whose picture here - I found it this morning ah ... [interruption - "Could we start that again?"]
I may come at a question from a different angle, to get a sort of slightly different perspective...
Yeah, you are sort of asking the same question over again as it were.
Yes. Had I had a chance to tell you what I was going to do today, you might have felt more comfortable with that. The thought was that we would look more thematically at things, and so looking at your attitude to nuclear power, and how it related to the bomb and so on was something I was coming at a slightly different way you know. I was getting into it from a slightly different angle from just the chronological one.
Well nuclear power was an off-shoot of the search for the nuclear weapon, it was quite ... discovered quite separately from the nuclear weapon, and the first reactor was built by Fermi on a tennis court in Chicago in 1942 I think. No.
So if we could go back, I will ask that question again. I was just ... I was going to explain before we started to roll, that today, we may approach some of the things slightly differently and out of their chronological context, to get a more abstract picture of your attitudes ...
(under Robyn) I'll do my best. I'll do my best.
(continuing) ... and the thoughts that were going through your mind. Right, and so therefore although it may be covering the same ground we want it fresh as if you hadn't said it before. So I'll I'll ask that question again. Given that Rutherford had, back in ... many years before, expressed a fear that someone may use this understanding to blow the world up, when you started looking with the MAUDE Committee and so on at the possibility of the use of this as part of weaponry, did that thought occur to you, were you worried about where they'd go?
Oh yes, right from the beginning, one had no doubts whatever of the horror of the situation, that here we had the possibility of mass extinction of people who were the work of man's hands in cities and so on. Whole city being blown to pieces with one bomb instead of with thousands of bombs of a normal kind. It was something that was really quite horrifying, and it was at the back of the minds of most of us who worked on it. Not of all of us. There were some people who just revelled in the purely in the science and in the objective, and didn't worry at all about the ultimate result, and ... but Niels Bohr was the man who really sort of led us in our worries during the war about the ultimate result of, if we were successful in the production of nuclear weapons.
And do you remember when it was that you found out what was going to happen or how it was ultimately used with the dropping of the bombs, and how did you feel? Could you describe that time?
Well you see, the difficulty is that one didn't know. When it became clear that a bomb was almost certainly a practical possibility, when we'd separated the isotopes of uranium and had stocks of plutonium, it was quite clear to us that the thing was going to be successful. One could ... the theory, there was no doubt about it at all in our minds. And at that stage, the fears that we had - what I might call the Bohr group had - became so great that Bohr sought an interview with President Roosevelt, and President Roosevelt was good enough to give him one and a half hours of his time to talk about, it and expressed considerable interest in this point of view, that this bomb, if it could be produced, should be used for peace and not for war. It should be - if it was exploded at all - should be exploded as a demonstration of what could happen to a country by, say, blowing the top off Fujiyama or something, and making it clear that the Japanese - the Germans had been defeated by that time by other means - what would happen if they weren't good boys. So ah ...
And why wasn't that course followed?
Well Roosevelt, asked Bohr for more information and then Bohr wrote a long screed about it, which I helped him to write because his English wasn't all that good, him being a Dane, and his wife said his Danish wasn't much better. So that it was a business in getting, to get a script that would, whilst concise and at the same time would be understood by the President. This interested Roosevelt, still more, and he asked for further information. There were some questions that arose from the first letter that was sent to him by Bohr, that he didn't quite understand and he asked for enlightenment. And Bohr prepared a second script which I also helped him with to some extent. He'd bring me bits of it and read them over to me and I'd criticise the English or the expression and so on, and then he sent that off to Roosevelt. But unfortunately before he read it Roosevelt died, and Truman took over, and Truman had no scruples whatsoever. So just through fate as it were, it looked as though Roosevelt was going to use it as a weapon for - he was interested at any rate in the concept of using it as a weapon for peace, rather than war. But of course, once the test in the desert took place in New Mexico and it was clear that all our fears were justified, it then was no longer the concern of the scientists, it became - it went straight into the hands of the military and the politicians. Scientists had nothing more to do with it.
And so you had actually left the project at the time of the dropping of the bombs on Japan.
Yes I went back to England, at that stage when it became obvious that everything was going to work out alright. In order to be able to translate the information that came from America to Sir John Anderson, who was the - as I said was the Lord President of the Council and was responsible for all these technical things under the Churchill Government, and so I was there in order to explain exactly what was happening when the bomb was used.
And how did you feel at that time, what was your initial reaction?
Well there was a feeling of utter frustration in that the message hadn't got across. That it had been used, and used against civilian cities, and that all the moral scruples had been thrown aside, by a so-called Christian nation, not by the Japanese or by infidels of any kind, but by a Christian nation or nations, because England was behind America in all this. And a feeling at the same time that well - perhaps we were wrong, perhaps this ends the war and saves lives, so at the moment there was that sort of mixture of feelings that one had. But added to that the hope that means would be found to control this weapon so it was never used again.
Your own feelings of doubt about it had, even before the bomb was dropped, aroused a certain amount of interest in you from authorities who were concerned about the quality of dissent that always ran through your work and your attitudes. And you'd already had an incident hadn't you that perhaps began to alert you that others would be interested in your political views in relation to the bomb.
In ah ... (under Robyn) in what way?
(over Mark) In America. You had a call from the CIA didn't you during the period that you were working on the bomb?
No, no, no, I never had any ...
... calls of that sort, but I had a lot of conversations with the FBI people, and also had arguments with them because a great friend of mine who was working on the project - a man named Martin Cayman who sent me a book which is on the table across there - only - I only received it yesterday, he's in Australia at the moment, in the Barossa Valley. And Martin Cayman was a very distinguished chemist, who was also a beautiful viola player, and we had contacts over music, and we had ... we became friends. I used to go and - he had played in a quartet with our friends, who were - one of whom was the first violinist in the San Francisco Orchestra and a Russian. And so ... there were suspicions about Martin Cayman [INTERRUPTION] and Martin Cayman in the end was dismissed from the project, and I protested very strongly against this, and I was in contact with the, particularly with Colonel Nichols who was the man in charge of security on the project, but I never got to first base, I ... I was listened to with - but there was no - no comment of any kind.
After the war was over, and you had this concern about trying to see to it that the nuclear power wasn't used in this, for mass destruction in that way again, what did you do about this? How did you put this into action?
Well I gave a lot of talks up and down Australia - in England and then when I came out to Australia, up and down Australia on the dangers of nuclear war and the necessity for world-wide control of this terrible weapon of mass destruction, which the numbers of which grew and grew, until they were so great that if they were all exploded in an exchange between say United States and Russia would have virtually made this earth a sterile earth because of the radioactivity that was released - spread all over the place, quite apart from the destruction that was caused of life and property and everything else. So I kept up my talk against nuclear weapons, then in 1951 I wanted to go to a conference in Chicago on the production of higher anti-particles for investigation of the nucleus and its properties, high energy physics as we called it, and my American visa I never got. The American Embassy here refused to say that it had been refused. But they always maintained it was late in coming. Hah! That it - of course by the time it came I - it was too late to go to the conference. But I'd kept on my correspondence with the American Ambassador and asked whether he couldn't in all conscience find out for me why I was refused. And he said that - the message I got back again was that through the first - the Deputy to the Consul - to the Ambassador was that - this was during the McCarthy era in the United States when everybody was under suspicion as it were - that I wasn't accused of communist sympathies or communist connections, but what I was accused of was of firing, of providing bullets for the Russians to use in argument against the United States.
This wasn't the first indication you had that your activities, your anti-nuclear weapon thoughts and beliefs had brought you into some sort of scrutiny by the authorities.
Oh, I knew that my relationship with Martin Cayman who'd been dismissed from the project must have made them a bit suspicious of me in some ways, and I knew that they were keeping an eye on me because on one occasion for instance when I visited some work that was going on in the in Canada. When I got to Ottowa, the railway station is down below if you remember and you go up a flight of steps to the foyer of the railway station. I went up the flight of steps, there at the flight - top of the flight of steps there was one of the FBI chaps from the place where my office was in Tennessee.
Sounds like a movie.
Obviously waiting for me. (laughs)
And so you.
I spoke to him, said hello. (laughs)
So you knew they were keeping an eye on you.
Oh yes. But I think everybody was under - who'd been associated with the - was working on the project. I was pretty closely supervised, and for instance the FBI had officers on the ground floor of the building, where my office was, and on the first floor my office, and every telephone conversation that was made by anybody in the building was recorded by the FBI down below. Every conversation, so that one had to be very wary in one's - even in talking to relatives or friends on the telephone. But one of the most difficult times was due to an Australian. A man named W. S. Robinson. A very famous Australian who was the Head of South Broken Hill, and the Chairman of the Zinc Corporation - later became Conzinc Rio Tinto and of course ran all the Broken Hill, South Broken Hill activities, and he was adviser to Mr Churchill on the procurement of metals during the war. He helped them to find metals that were difficult to get for production of munitions of various kinds. Well, I picked up the telephone, or at least [the] secretary came and told me I was wanted on the telephone, and I picked it up and a voice said to me, 'Hello Mark', and I said, 'Hello, but who's that speaking?' 'This is W. S. speaking'. He always called himself W. S., W. S. Robinson, and I'd got to know him very well in England , because his main - main office was in in London in, almost opposite the Palace, at ah ahh ... of I've forgotten the name of where ...
(Interrupting ) Anyway he was having this conversation with you in America.
Yes. And I said, 'What can I do for you W. S.?' you see. He said, 'Well I - look I want to talk to you about uranium'. Now uranium of course was a secret word which wasn't mentioned in public by anybody, and I was horrified you see and I said, 'Wait a minute W. S. Wait a minute W. S.', and he said, 'It's alright Mark. It's alright Mark. I know all about it. Winston's told me all about it'. I said, 'Well I'm sorry but I really can't answer any questions at all'. But it was a delicate moment I can assure you.'
Especially knowing who was listening.
When you went back to England after the war, were you conscious in settling yourself back into the English scene of any kind of particular scrutiny or concern that was going on there about your political attitudes.
No, no, no, no, I don't think there was anything of that kind at all. They ah ...
So you were invited onto all the committees and you were ...
Oh yeah, for a while but then it became secret and I didn't want to be involved in any secret work, apart from the fact that, you know, obviously people were a bit suspicious of me in some ways, that I might, because of my antagonism to the nuclear weapons, I might be indiscreet.
[end of tape]