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Interview of Mark Oliphant by Charles Weiner on 1971 November 3, Niels Bohr Library & Archives, American Institute of Physics, College Park, MD USA, www.aip.org/history-programs/niels-bohr-library/oral-histories/4805
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Reminiscences of studies at University of Cambridge and of the 1851 Exhibition Science Scholarship from 1927. Recollections of Ernest Rutherford, work with him on measurement of the energies of the product particles after Cockcroft-Walton, and on transformation effects on deuterium brought by Gilbert N. Lewis from University of California at Berkeley. Working conditions at Cavendish Laboratory; criticism of Rutherford by Advisory Council of the DSIR (Department of Scientific and Industrial research); change in focus at Cavendish after Rutherford's death. Trip to Berkeley in 1938 to study design of 60-inch cyclotron as model for Birmingham cyclotron. Also prominently mentioned are: Francis William Aston, James Chadwick, John Cockcroft, Kerr Grant; Nuffield (Automobile manufacturer), University of Adelaide, University of Birmingham, and University of California at Berkeley.
As I indicated, the thing that interests me at first is the development of your own career up until the time you came to Cambridge. I would like to know briefly about your family background, how you became interested in science, and then from there I have a few questions about your prior education.
Yes. Well, my father was a civil servant in South Australia, and my mother had been a school teacher before she was married. These two folk were both very interested in literature, in what are called arts nowadays. So the whole influence on me in my early years was in reading classics and one thing and another. When I was reaching the stage of going to the university, I intended to become a Church of England parson. But I was weaned against that, I think, by the fact that not many parsons that I met seemed to come up to my ideals. I was very much, you see, what in America today is called a "do-gooder" at that stage of my existence. So I decided then that I’d do medicine. But when I started to do this, I found very rapidly that I wasn’t interested enough in people as individuals, and I didn’t like handling people, having anything much to do with people physically. So in the end, largely through the influence of a professor of physiology named Brailsford Robertson, who got me to help him with some trivial little research, I got much more interested in the scientific side. I decided to take chemistry, found that that was based very strongly on physics, and so turned over to physics. That’s the way I got into physics.
How far had you gone in your premedical training?
Only a year. So I’m one of those people who in his younger days was unable to make up his mind about what he wanted to be, and therefore I suppose I’ve never done anything very much. But what interested me and made me really determined to come abroad was that Rutherford had been on a visit to New Zealand, in 1925, I think it was, and on his way through by ship, he stopped off in Adelaide and gave a lecture at the university, which very much interested me, about the work that was going on in the Cavendish Laboratory at that time. So I made up my mind I would, if possible, come to Cambridge and work with him.
Did you talk with him at all on that visit?
No. He was, you know, "Up there somewhere." I was amongst those who never got anywhere near him except to hear him. Then I got the opportunity to do a little bit of work with a man named Burden there [in Adelaide] who was a lecturer in physics, a don, and did some work there with him on the surface of mercury, on the properties of the surface of mercury, adsorption of gases and so on. I subsequently published it, and as a result of this got an 1851 Scholarship to come abroad, and that was it. I came to Cambridge. Rutherford was kind enough to accept me. I telegraphed him and he telegraphed back to say held keep a place for me, and I came here.
Let me interrupt at this point to ask whether in the physics program in Adelaide there was any orientation toward the Cavendish?
No, none whatever. But I can tell you one thing that happened to me. The professor of physics was a man named Kerr Grant. He was a quite extraordinary man; although held never done anything very much in his own life in physics, he was quite an inspiring teacher. And I remember one of the things that he talked about to us, when we were getting on to be advanced students, was about the constitution of matter, the constitution of nuclei and so on, and the possibility of transmutation of atoms. And he spoke about work which held read about concerning claims made in Japan by a chemist who thought that held made gold out of lead or what not, but subsequently discovered that the gold that he discovered in minute quantities came from the frames of his glasses which he was in the habit of handling. But this made me a bit interested in this problem, and I thought about it a bit and decided that perhaps there was a chance that if one could bung electrons into uranium, one could stimulate the formation of uranium X. So I set up a device in which the anti-cathode of an X-ray tube, which I made, was a water cooled copper target with an indentation in it in which I put the uranium, which had been carefully purified from the radioactive products of its decay, and bombarded it with electrons for a long time, at about I suppose 100,000 volts. That was all I could get from an old induction coil, a large induction coil, and at first I thought that I was getting a positive result. The radioactivity as measured with an ionization chamber definitely increased. But I found it was just due to the fact that the target under the heat of course tended to fuse and crack so that there was a bigger surface area. But this made me interested in nuclear things and in nuclear transformation problems.
Did you have the freedom and time to do this experimental work at the university?
No, I had to do it on my own time. I was employed in the physics department as a sort of a “dog's body."
Which means what?
I got the opportunity to do this because the professor of physics, Kerr Grant, whom I mentioned — whose offsider I was, you see — went away for a year's sabbatical leave, and Burden encouraged me very much to do what I wanted to do, so I did this work on surfaces with him because of his past success and because I knew I’d get something out of it. This other was just a shot in the blue.
At what stage did you get a degree in Adelaide?
I got a degree, an ordinary degree in physics and chemistry, in 1921, when I was 20 years.
When did you enter the university?
I entered the university three years earlier.
The degree in 1921 was equivalent to what degree in Cambridge? Was it exactly the same system?
Yes, it was a very similar system. Then I went on to take an honors degree which I got a year later.
Yes. Then from '22 till 127 I was doing this job as I said in the University of Adelaide.
Would there have been a possibility for higher degrees within the university?
At that time, no, nothing except the doctorate, of course I mean DSc — at that time there was no PhD. But I don't know, I suppose I didn't have very strong ambitions in those days. It wasn't until Rutherford came along that I discovered how exciting these things could be.
Was it the practice to channel people who wanted to go on to a PhD into other universities in the Commonwealth educational setup?
To some extent, yes. But it depended very much on oneself. The only thing the university did for me was to give me one of the free passages, steamship passages. There were two of them available each year to the University of Adelaide, given by the shipping combine. I got one of these and came round the Cape with the Blue Funnel Line — took seven weeks in those days. But it was nice.
Who made the arrangements to go to Cambridge? You mentioned the exchange of telegrams.
That was all that happened.
Did you do that; apply as an individual, on your own?
Yes. I wrote them — having got the agreement of Rutherford, of course it was necessary to get into a college, and I wrote off to Trinity College and was accepted by Trinity.
No one in Adelaide had first written a letter of recommendation?
Just having been awarded the 1851 was enough.
And your application for the award of that was done strictly at Adelaide?
Yes, that's right, through the university, of course. You had to do it through a university. It went through Burden, you see, who was so kind to me at that time.
I don't know the procedures for the 1851, but is there any point at which you had to specify what your interests would be?
Yes, you're asked what you would like to do.
What did you say?
I said I wanted to work in the Cavendish.
Did you specify a subject?
No, because I didn't know enough about it.
I see. But you already had begun to focus on nuclear problems as you described it.
Well, I did that piece of work, but that was all I did. And when the professor came back again from sabbatical leave, of course I didn't have any time, and we moved into a new laboratory which involved me in a lot of work moving the equipment and so on across to the new lab. I was engaged on that for a year or two. And the professor had one or two ideas of what he wanted to do. He was very keen to make diamonds, and he had an idea that diamonds might be made by the solution of carbon at very high pressures and temperatures in mineral oils which existed in the earth. So I had to see whether I could get any evidence of this, by heating carbon filaments, out of old carbon filament lamps, you know, in oil, and blowing the whole thing up to a couple of hundred atmospheres with an old compressor we had for making liquid air, and seeing what happened.
This was something that didn’t interest you personally, an assignment.
I was helping a laboratory assistant named Eimer, an electrical engineer, but it didn’t interest me personally. It was just an assignment. I did it as best I could. Of course nothing came of it.
One further question about Adelaide — in your physics studies, did you get any theoretical work?
Oh yes. Theory in those days, you see, was in a very elementary state as compared with today, but we did very thoroughly Sommerfeld's book on atoms and spectral lines, which of course involved a good deal of the earlier quantum theory. Professor Grant was very alert to what was happening. I was never a first class mathematician, but I was very well introduced to theoretical physics.
It probably was too early to get the results of the new quantum theory which was developed in '24, '25, '26.
So the closest you had to it was Sommerfeld’s book.
Through Sommerfeld, and there was a German book, I’ve forgotten who the author was, which was an introduction to quantum theory, too, and which was available in those days.
And as far as journal articles — what kind of time delay was there in getting the major journals?
Well, about a month, a little more than a month. But one of the things that I later on was rather proud of was that we had a little colloquium in physics, where we took turns, the few of us there who were interested in further study in physics, to give a paper about something that was happening; and I found in a French journal a very interesting paper by de Broglie, which intrigued me because I’d been rather interested in optics. He developed, you remember, his first approach to wave mechanics through optics. I gave a talk on this at the colloquium. And it wasn’t until I got to Cambridge that I really realized that by accident I’d hit on rather an important paper.
You selected it because it interested you, not recognizing its significance.
I had no idea that it was something very important. It seemed to me to be an interesting idea, that’s all.
Good taste. The other participants in the colloquium were students and faculty as well?
Only honor students, which meant three or four students in a car.
Did any of the professors participate?
You see, there was only one professor there, and then there were about four or five members of the faculty other than that, and then a “dog’s body” like myself. I was labeled the professor’s assistant or something of that sort. I never knew what my job was. I knew that I collected a modest income for helping round the place.
What would have been your expectations had you remained there?
I suspect the best I could have hoped for would have been a lectureship or a readership.
Most of the professors would have PhDs from Cambridge or some university?
No. Professor Grant only had an MSc from I think the University of Queensland, and he had been abroad and had studied for a year in Germany, so that he had rather fluent German. This was very helpful to us because he was able to translate the German periodicals and so on, rather more freely than we could. We used to sit down with him, you know, and held read these things.
My interest in this is in the general problem of physics in far out places and how it relates to the world system of physics.
Yes. But at that time, you see, unless a young man got away from Australia, he didn’t have much hope of doing anything of interest. Life was very like it is in some of the small colleges in the States. It was pretty well a routine teaching job.
Getting back now to Cambridge, you said the first thing was to get acceptance from Rutherford. That means acceptance as a research student at the Cavendish?
Yes, that’s right.
That was for the fall term?
I'd be interested to know what happened after that seven week trip, what your first encounter with Cambridge was like?
Coming from a new and fresh country, the thing that struck me about England was how incredibly grubby and dirty everything seemed to be. I had no appreciation at that time of the old for its own sake. When I came up from London and went in to see Rutherford, he had an office off a little passage that ran through the older part of the laboratory, which had no floor covering on it at all, just bare scrubbed wooden floors, and rather grubby looking walls on the sides that hadn't been painted obviously since the place was put up. I went to the room next door to his office, where he had an assistant. I think officially he was the lecture assistant but he also served as Rutherford's sort of secretary. Rutherford had no woman secretary or anything. Hales was his name — he called himself “Hiles” — or it might have been Hayles, I'm not sure about that, but he called himself "Hiles.” He was a man who hated smoking and always made a fuss if anybody smoked in his room, despite the fact that Rutherford smoked like a volcano. There was somebody else in with Rutherford, but in the end I went in. While I was waiting there in the passage, I was joined by a young man from Dublin named Walton, who was also taking up his work in the Cavendish at that time. Finally I got in to see Rutherford, and nobody could have been nicer. But the thing that impressed me was this incredibly cluttered room with papers all over the place. The windows looked as if they'd never been cleaned since donkey's years. They were covered with grime and dirt. It was a watery sun like the sun today that scarcely penetrated into the room. And Rutherford was sitting behind one of those old-fashioned roll top desks, which was also cluttered everywhere with papers. It was rather hard to find anywhere to sit down, as a matter of fact. But he received me most kindly, and talked to me about what I wanted to do, seem rather pleased that I had a few ideas as to what I wanted to do, and he let me go ahead and do them. But the important thing from my point of view was that I had a young wife with me, and Rutherford was interested in this and asked us round to tea that Sunday afternoon. We went along, and we found there a large group of people. Kapitza was there with his new wife, and Aston, and various other folk. We were received by Lady Rutherford at Newnham Cottage, which is on the so-called "Backs" of Cambridge. She was a strange contrast to Rutherford. She was dumpy and abrupt in her manner. And Rutherford received us. By the way, Rutherford had an extraordinary habit — for a man with such a booming voice and such an outgoing personality, he shook hands like a wet fish. There was no muscle in his handshake at all. It was a very limp one indeed. But the Rutherford’s were very interested in us, for some reason, and we rapidly got to know them very well personally. They took us away with them on holidays to a country cottage, first of all in Wales and then to one they built in Wiltshire, so that we got to know them extraordinarily well as persons. And this made my stay in Cambridge — I stayed here ten years, till his death — very pleasant indeed.
How do you account for the fact that you hit it off so well, that he took such a liking to you?
I haven't got the faintest idea. They had only one child, Eileen, a girl, who married Ralph Fowler, a theoretician. I think she was a bit of a disappointment to them in some ways. And perhaps he liked us because we seemed like the sort of children he might have had, or something of that sort, or she did. But we soon learned what a warm-hearted woman she was. Though I never, in the whole of the time I knew them (and of course I knew Lady Rutherford till she died years after his death), saw them show in public any overt signs of affection.
To one another.
To one another. When he went off in the morning or to London or anywhere, he never kissed her or anything of that sort. It was on the whole, just like two people living in the same house and sharing the same things. But she was wonderfully good to him. She nursed him with infinite care if he got sick, got a cold or anything. It was she who, when his study became just too cluttered up for words, arranged all his papers and letters. It's due to her that so much of his correspondence and so on, has been preserved, entirely due to her. She was a rather remarkable woman in that way. Very interested in her garden, where she got us to help her very often, doing things I didn't particularly like to.
Well, it's better than making diamonds. (laughter)
Rutherford, for a man who was so entirely engrossed in his work when he was in the laboratory, and who obviously thought of nothing else during term time, when vacation came, got away and just relaxed completely and utterly. He put everything behind him.
Was he able to do that even in the course of a single day? To find moments of relaxation each day?
No. He always had his work, during the years that I knew him — he was what, when I first knew him? '57, '56, — even at that time, he did no more than have a doze after lunch in his chair. He always went home to lunch, which is an indication once again that home was an important place to him, even though there was this rather strange relationship between them.
He was a man of regular hours as well.
Very regular hours and he always established a very regular pattern of what he was doing, even when he was away.
That's a complete story in itself, I think, of the personal psychological portrait of Rutherford. Let me get back to your personal story here. After your first meeting with him and after the relationship of friendship began, what was your assignment when you told him of your problems that you were interested in?
I worked on some problems concerning positive ions for a while.
Did he say you would be working with so and so?
No. I started off on my own, but very soon afterwards I was assigned a research student to work with me. I suppose because I'd had some experience in research. Philip Moon, who's now professor of physics in Birmingham, was the first such man. Then I had a number of others.
How did you check into the laboratory? In what way?
Oh, I was assigned a corner in a room, in a large room upstairs, not very far from Rutherford's office, where there were four or at times more people. In one corner near where I worked there were two, Millington and White. In the opposite corner, there worked J. K. Roberts on — what do they call it, I’ve forgotten what the technical term is for the exchange of heat between a gas and a surface. There's a term that's used for the fact that it's not unity, which the gas molecules don't come to the temperature of the surface. But J. K. Roberts worked on this and for the first time showed that if you had a very clean gas, sayan inert gas which is very clean and a very clean surface of tungsten, that this accommodation coefficient — that's it — could become extremely small. The molecules or atoms could bounce off without any appreciable exchange of heat with the surface at all. This interested me at the time. I was working on the production of secondary electrons and the scattering of ions from so I’d surfaces at energies up to a few hundred volts. And across diagonally from me in the same large room, there worked Bullard, whom you must know, and Massey.
Massey was from Australia, too.
That's right, yes.
So this was the geographical surroundings. Was there any person to whom you would be responsible?
To James Chadwick. Rutherford of course, ultimately, but through Chadwick. I can tell you how I got to appreciate Chadwick. I was brash enough to go and ask for what I wanted in the way of equipment and so on and it was very meager in those days. One had to put up with what one could get. I was a pretty good glass blower in my own right, and this was a great help. But the vacuum pump that I was given, to back the mercury glass diffusion pump which I made for myself, was one of those things you turn a handle on — a Fleuss pump, I think it was called. And since I was admitting gas to my apparatus to make my positive ions, pumping with my hand was a bit of a chore. So rather soon after I'd got going, and I was getting some results and so on, I remember Chadwick coming around one day and sitting on the corner of the bench talking to me about what I was doing, and finally saying to me, "Well, is there anything you want?" And I said, "Yes, I'd like a motor driven vacuum pump, a High-vac pump, if there is one available." Chadwick in those days used to pull his glasses down and look over the top of them like this, you see. He pulled them down and looked at me and said, "So you want a High-vac pump, do you?" I said, "Yes, Dr. Chadwick." He said, "Well, you just can't have one." (laughter) At the interview but not on the occasion!) Then he went on to explain, there wasn't any money to buy one with. But I was a bit put out by this. I went along to lunch, and was away from the lab a little longer than usual. When I came back, there on the corner of my desk there was sitting a High-vac pump. So I learnt in my very earliest days that Chadwick's bark was much worse than his bite. And I got on very well with him.
So you'd go to him for special instruments. What about discussing your work, the results and the problems you'd run into? Was that more with the other people who were working?
No. There was nobody working on related problems. I used to go and talk to Aston sometimes, who was interested in similar problems. But he was so senior and was much more interested in telling me what he was doing and the problems he was having in the electrostatic deflection that he used in his new mass spectrograph. The deflecting plates were plated with gold, but he still got double layers forming and patchy electric charges on the surface, which spoiled the accuracy of the mass spectra that he was getting. I got on very well with Aston, but amongst most people in the laboratory he had a reputation for being rather short-tempered. One thing, he had never had anybody to work with him. When Ken Bainbridge (who was over here for the Rutherford celebration, and by the way is still here, I think), came over to spend a year in the lab because he was working on mass spectroscopy and thought that he'd like to get some experience with Aston — he found it very difficult going indeed. Anyway, Aston was one of the people I could talk to. But it was mostly Rutherford himself and Chadwick. Both of them were very patient with me and very kind in their criticisms and talk. And this was quite a productive period, although the work was not of any great importance. I got quite a lot of work done and I got my PhD after two years.
This is listed as between the '29 and '30 academic years. When was it, spring of 1930?
I can't remember. It was two years. I took it in the minimum period that was allowed. I put in my thesis and got my degree.
Among the others who got it that year were Allibone, Lea, C. F. Powell, and E. J. Williams. Those are names that I recognize. I think there were others as well.
Oh, there were probably others as well.
There were about four or five others, I think, a rather large group for that time.
Now, those individuals, for example, were not the people you mentioned as having had anything to do with in terms of your research.
No. Powell had already left the Cavendish. He came back to take his PhD degree. He was in Bristol, and although I got to know him, I never discussed my work with him. Who else? Allibone. Of course, Allibone I knew very well and still do. I’ve always kept up with him. He was working at the time on this business of accelerating electrons to high voltages, using a Tesla coil as his source of voltage, and pear-shaped glass bulbs with steel electrodes in them. It was he really, who introduced into the laboratory the oil diffusion pump of Burch, because Allibone came from Metropolitan Vickers, and Burch was of course at that time working at Metropolitan Vickers, and Allibone used the oil diffusion pumps on his equipment and taught us how to use the things. This made a very great difference to a lot of work at the Cavendish, the introduction of the oil diffusion pump early in the game. Who else was there?
Williams, E. J. Williams.
E. J. Williams, of course, was working with an expansion chamber and although I took an interest in what was going on in that field — Feather was working in that field and Terroux and Nimmo, they were all working in that field — I never did any work in that field myself. E. J. Williams was a very able man. It's a great pity he died so young.
He did some very interesting theoretical work.
Oh yes, he did. He was a very able man. And of course, he got the positive electron and probably the meson before anybody else, but at that time he never got any encouragement in his interpretation.
He was an unsung character.
Yes. Although he was a very forceful character, E. J. Williams — the way he spoke. His words came out, you know, in bursts from him. He was very Welsh in his manner, very incisive indeed.
I notice his letters show up in the Bohr correspondence and other places, dealing with very interesting ideas, on the top level. Getting back to the earlier time of your arrival, did you go through any orientation program?
No. You see, the people who'd had no experience of laboratory techniques and so on, were given what we called a kindergarten course by Chadwick up in the 10ft of the laboratory. He gave them the most difficult jobs he could think of, like making a tilted electrometer work, the sort of things that really made them pull their socks up and learn a little bit about not only how the damn thing worked, but how to make adjustments in the right sort of way. And he gave them other odd jobs up there. Afterwards, they were allotted a job.
You went straight into it and worked alone throughout this period, up to the point of the PhD?
How do you mean?
You worked on your own problem. You didn't work as part of a group.
No, except if I was assigned these folk to work with me. First of all Moon, then Chaudhri, an Indian.
Yes, you mentioned them. Now, they worked with you. What was your role with relation to them? Were you supervising them?
No, no. Rutherford supervised everybody in the Cavendish, in theory. It was a strange arrangement. You are very glad, you see, if you're doing work, to have somebody allotted to help you, and people who were getting on and had some experience and were obviously able to guide younger people were allotted research students. Indeed, the system at that time — and I think it was a very good one, personally I think it was a better system than has grown up since — was very much an apprenticeship. You were apprenticed, if you were young and inexperienced, to somebody whose job it was to teach you how to do physics. And this I think was very much more effective than any courses could possibly be. Of course, we worked long hours and we worked very solidly in those days. The laboratory was open till 6 o'clock in the evening. If you wanted, by special dispensation you could work later than that, but Rutherford maintained that the evenings were a time for thinking and writing.
Did the people working with you then choose related problems for their own?
No, they just worked with me on what I was doing.
Chaudhri went on to get a degree, didn't he?
And his dissertation, would it have been on some aspect of that problem?
So you could take something of it out —
Oh yes. This was part of one's job. One had to see that they had part of it which was theirs.
The point I'd like to jump to, because we don't have as much time as we really need for this, is the next period, from 1930 or late '29, whenever it was exactly that you got your PhD —
1929 it was, but exactly when, I don't know.
Until 1935, when you take up a position of assistant director of research. My first question is on your status, what position did you have?
I had a variety of positions. First of all, I got a senior 1851 Scholarship which carried me on beyond the two years, and then I got a research fellowship from the Royal Society called the Messel Research Fellowship, and that carried me on until I was appointed to a lectureship and fellowship at St. John's College.
When was that?
I would say early 1935.
The Royal Society Fellowship was through Rutherford? Was it his proposal? How did it work?
Well, he suggested that I put in for it, yes. I don't know what opposition there was, if there was anybody else or whether I was alone in applying for it. It just came in due course.
So your title then was Royal Society Fellow, Messel Fellow?
You had no specific function in the laboratory, no responsibility other than to pursue research. And some of the research was in conjunction with Rutherford?
Yes. Immediately after Cockcroft and Walton made their first observation, Rutherford called me in and asked me whether I would work with him in this particular field, which he was very anxious to exploit to the full in the laboratory. And of course I was rather flattered to do so, and was very glad. At that time I was trying to separate the isotopes of potassium in order to find which of them was radioactive, and my experience in the previous work with ions and this work on potassium was such that I was very ready, as it were equipped, to go straight into this other game. I built up a piece of equipment in the room that lies between that in which Rayleigh first measured the ohm and where Rutherford and Chadwick had done most of their work on transformation by alpha particles, and the room where G. I. Taylor was working on his hydrodynamic and aerodynamic problems. Of course the equipment was built up once again out of all the odd pieces one could find round the place, bits and pieces of an old X-ray unit and so on. We built it specifically not for high voltage, as Cockcroft and Walton had done, but exploiting the fact that one could observe transformations with the light elements at relatively low energies. So we went for a maximum of 200,000 volts, and we usually worked much below that.
How was that decision reached? Does that come from your thinking?
Yes. In looking at what Cockcroft and Walton were doing and the problems that they were up against — Rutherford was very anxious to measure the energies of the product particles as accurately as possible because he was very interested in the exact mass-energy relationships of the masses of the particles, and wanted to see some sort of coherent picture that tied up with their work on alpha particle transformations. And so this was done. It was decided that the higher you went in energy with the bombarding particles, the more uncertain was your energy of the emitted particle, because of course the energy of motion is added to the energy of the transformation. And since you have more penetration into the target by the faster particle, and a greater distance for the product particle to come through the target material, the uncertainty in the energy became quite large, compared with what one ought to be able to measure. Of course, the only measure we had of the energy was the absorbability of the particles. We used mica and air, and also made definite identification of the particles, not only from their ionization but by measuring their velocity in crossed electric and magnetic fields. A man named Crowe whom you may have heard of, who was Rutherford's technical assistant, came and worked with me on this, getting all this going. He was a wonderful technical man on this sort of thing. Wonderful help to me. He taught me how to split mica so that one could get definite absorbing powers in the mica, and we built up equipment so that we could measure these energies with great accuracy and very quickly. We had a sort of vernier arrangement of absorbers that could be rotated very rapidly in front of the detector, which of course when we first set out, was a scintillation screen, but we very rapidly changed over to an ionization chamber and counter that was made up by Wynn-Williams for us.
It was built especially for you?
By Wynn-Williams, yes. It was of course a very elementary thing, but it worked incredibly well. He had taken up the work of Greinacher, who'd first proposed this. Rutherford of course had had experience of such techniques in the very early days when he was counting alpha particles with Geiger in order to determine how many came out. So it was very rapidly rather refined in the laboratory. He introduced the idea of the differential chamber, which of course was quite a great advance in getting accurate results.
Did Rutherford participate in the tuning up stage?
No, not at all. He left us completely alone in the design of the equipment and in the carrying out of the experiments. All that he did was to discuss the experiments. He even left me alone to decide what experiments to do next and so on. We started out of course by re-measuring the lithium results and getting some rather accurate figures for that, and then went on to boron, and found that this was complicated by the fact that 3 alpha particles were emitted in the disintegration of boron-1l by protons. This fascinated Rutherford, who did an awful lot of arithmetic. He had the very valid idea that probably that happened was that one got, first of all, a carbon in a very highly excited state formed by the absorption of the proton; then the thing broke up into an alpha particle plus a bery1lium-8, which was in an excited state; and that subsequently broke up. He tried to get evidence for this and did an enormous amount of arithmetic on our experimental results. Of course, we just got a continuous spectrum of alpha particle energies, and in the end he was not able to make anything of this. He spent an awful lot of time over it, did an awful lot of arithmetic on it, but it was abortive.
But there were some very positive results and it seemed to be a very productive period.
Oh yes, it was, very. Then G. N. Lewis visited the laboratory from Berkeley, and brought with him and gave to Rutherford about one-fifth of a cubic centimeter of heavy water. It was in three tiny little bits of glass tubing, sealed up in them. These were viewed with great awe of course because it was the first time weld seen this material. Of course G. N. Lewis was the man who first concentrated it, and it was very good of him to give this stuff to Rutherford. In the end I used one of these ampules to obtain some deuterium by reacting the water with potassium metal, because we thought then weld have heavy potassium hydroxide which might be useful in some other way. We didn’t want to lose the deuterium. We bombarded everything that we could think of, especially light elements, with the deuterium; because we had such a very small quantity of it I mixed it with a rather large volume of helium. From my experience with ions and discharges, I knew that having such a high ionization potential, excited helium atoms would be quenched by the deuterium and produce ions of deuterium, so that from that mixture of say one part of deuterium and ten parts of helium, one could get practically the same deuterium beams one could get from pure deuterium. Then I had to make arrangements of course for recovering the gas after it had been through the equipment. And it was recovered in charcoal, cooled with liquid air. But before that all the other muck that came from oil pumps and so on, was frozen out by liquid nitrogen boiling under reduced pressure so as to get the temperature down as low as we could, and indeed we circulated this stuff for a long time in the equipment. But we rapidly observed that everything that we bombarded, no matter what it was, gave us a long range group of protons and a short range group of what we decided were tritons, hydrogen of mass 3. This was all right, but we then of course worked out the reaction that was giving us this thing, and assumed that because everything gave us the same sort of answer, what was happening was that the beam was sticking a bit to the target and subsequently it was being bombarded by the deuterium. So then I took some of this heavy potassium hydroxide and plastered it onto the target and of course got enormously enhanced results. So we went on from there to unravel the deuterium reactions. That was a very exciting period, getting that worked out. It1s hard to put oneself back into a situation where what seems so obvious today was such a mystery to us. You see, one of the great difficulties was that from these reactions we got long range protons. We got medium range tritons. We got neutrons in large numbers. In the end I managed to split a bit of mica so that it only had a stopping power equivalent to about one and a half millimeters of air (which had brilliant interference fringes, colors) and made a window out of this with Crowe's aid, and immediately observed a short range group of what appeared to be alpha particles. Well, there we had alpha particles, tritons, and protons, and they were there in exactly the same amount, as far as we could measure. Now, since they came in the same amount, it seemed that they must have originated in the same reaction. And we worried and worried about this. Rutherford did an awful lot of arithmetic on it, never got anywhere of course. Then one night, after weld had an especially long day fiddling around with these things, I went home to think about it and so did Rutherford. I went to bed in the end, but Rutherford didn't, and at 3 o'clock in the morning he rang me up. He apologized for ringing me up at that time and getting me out of bed and he said, "Uh, uh," as he always did before he spoke, "Oliphant, I think I know what those short-range particles are, how they originate. I think I know what they are.” I said, "Well, what are they, Professor?" He said, "I think they're helium of mass 3." I said, "But how on earth can you deduce that? How on earth can we get a proton, a triton, and helium with mass 3, not to speak of the neutrons, out of the union of two particles of mass 2?" He said, "Reason, reasons, Oliphant? — I feel it in my water.” (laughter) (During interview, not at the time.) Well, next day of course we set to work, and he was right, as he always was on that sort of thing. And we tied the thing up pretty thoroughly.
How soon after was it published?
Oh, it was only a matter of days before it appeared in NATURE.
It appeared in NATURE in days? How does one publish that rapidly?
You have no idea what pull Rutherford had in those days. After we had an agreed version of a note to NATURE, and it went off to NATURE, it was certainly not more than a week before it appeared.
Did you preserve any of the laboratory notebooks on that experiment, that series of experiments?
Yes, I’ve got them at home, but they’re not terribly interesting.
They might be interesting just in tracing the time lag, for one thing.
Yes. But it was certainly less than a week. It was the most rapid bit of work I’ve ever seen go through in my life. The morning after weld tied the thing up, which was the next day; I called in at Newnham Cottage with a version of a letter to NATURE. Rutherford scrawled allover it with his pencil. He had this habit, you know, of having in his waistcoat picket three or four bits of pencil, not more than an inch and a half or so long, with very blunt points, which he used to drag out. He held them very awkwardly between his thumb and his forefinger, and he wrote very slowly with them, and he scrawled all over this typescript. He didn’t come in till about 10 o’clock. I took it into the lab, got it typed, all ready for him. He came in, and he made one or two further alterations, and then it went straight off to NATURE that day and appeared in the following week's number.
Did he have a policy on publications which meant that everything would go through him?
Everything in the laboratory went either through him or through Chadwick. Chadwick was the man who did most of the vetting of papers. Chadwick read the papers, and he was an incredibly good critic of writing of papers. If you read that paper of Chadwick's on some notes on the search for a neutron, do you know that? It was published in Ithaca.
Yes, it was a very brief paper, but very concise.
Yes. Well, now, that was his style.
You were talking of the 1962 Ithaca paper of Chadwick's as an illustration of his style.
Yes, and he tried to make us see that that was the way to write a paper. One had to be terse. Rutherford hated verbosity in papers, too. He wanted one to be as short as possible. He hated it also in a thesis. He said once to me that any man ought to be able to write everything that he knows, that has developed in the course of his PhD work, in 80 to 90 pages, and he said that he didn't think it was possible to justify more than that. But Chadwick was equally in favor of conciseness in writing, and we used to hand our papers in to him. He would read them and then they would be communicated by Rutherford to some suitable journal.
Would there be any expectation on the part of Rutherford or Chadwick of a certain productivity, in terms of numbers of papers?
No, this never seemed to be on the minds of either of them. What they demanded was hard work, damned hard work in the laboratory. There was one chap, a Canadian, in the lab — I remember at tea one day, — we used to have afternoon tea in the lab — Rutherford was there and this chap came in. Rutherford said, "Hello, so and so, how are you getting along?" This fellow said a few words and Rutherford said, "You know, I don't believe you’re in the laboratory and working hard because your hat's hanging behind your door.” (laughter) This fellow liked the ladies a lot and he was apt to be very late in the morning and so on. This was the sort of way that Rutherford gave him a gentle hint. And it was impossible to be lazy in the lab with either of those people about.
Did they expect results? Working hard is one thing, but —
— no, they didn't expect results. I mean, they didn't expect necessarily that any particular bit of research would lead to results that were interesting or publishable. They hoped it would of course.
In your case you worked with a number of people on a series of papers between '33 and '34, all on the same line.
That's right. There were various people joined us in this work. There was Kempton; there was Paul Harteck, and Miss Maasdorp.
I don't know of her name.
Maasdorp — she was from Rhodesia.
Was she a research student as well?
And Harteck. Then Shire was on one paper.
When we thought we understood the reactions, the transformations of lithium, and the allocation to the two isotopes of lithium, Rutherford was still very anxious to tie everything up. He wanted there to be no doubt about these things. So he wondered, since I'd been trying beforehand to separate the isotopes of potassium, whether it would be possible to make a sufficient separation of the isotopes of lithium to be able to nail down our interpretations. And I got Shire assigned to me as a research student, and we talked about various ways of doing it. Shire was very alert at that time, very alert indeed, and he suggested that the quickest way to get a reasonable quantity of material collected in a short time was to do a velocity analysis rather than a mass analysis — that is to say, to pass a rather large cross-section beam of lithium ions through crossed electric and magnetic fields. And he did this, and it worked out very well indeed. We immediately checked on the reactions. Everything came out very nicely. Rutherford was very pleased with this, very pleased with Shire that he'd done it so quickly and so well.
Crowther was one of the people on that paper too, wasn't he — Shire and Crowther worked with you on separation and transmutation of the isotopes of lithium.
And an earlier one, both in 1934.
He was also assigned? Or borrowed?
Yes, he was assigned. He was a research student.
This implies that Rutherford had in mind, at least for the questions that he was personally interested in, a research program. In other words, a series of experiments.
No, no, no. The program grew as the experiments went along. One followed one's nose. He didn't think that one could plan these sorts of things very much in advance, because one never knew what one was going to get. And one never knew what results were going to be interesting and what results were going to be just either uninteresting or obvious. And of course the things that interested him most were the things that weren't obvious.
Well, it's interesting how he got involved in this line of work that you're describing now, which was the result of something internal, the Cockcroft — Walton work. Were there also any external developments that stimulated him — in other words, something that was developed quite independently of anything going on at the Cavendish? Which he then...
No, there wasn't anything going on, you know. He still wanted some of these reactions to be seen in the expansion chamber. This was the ultimate judgment. So he got Dee to join in this work, and Dee built up another accelerating tube and so on that ,could be used with Cockcroft and Walton's high voltage equipment alternatively, when they weren't using it, and he got beautiful pictures. But before he could publish — I've forgotten the name of the journal now — some very nice pictures of the lithium reaction were published from Germany. But there was nothing from outside. We never believed the results that were being obtained in Berkeley by Lawrence and company. Lawrence, you remember, promulgated the idea that the deuteron broke up in collisions. He and Rutherford had a bit of an argument at the meeting in Brussels; the Solvay Conference. But Rutherford liked him very much. Rutherford called him "that brash young man. He said, "You know, I was just like that myself when I was young." But it was very interesting trying to persuade the Berkeley people — you might have seen some of the correspondence — that it was much simpler than they thought.
Well, Tuve played a very important role in that, I think, because the dispute seemed to be between Lawrence and Cockcroft, and then Tuve began to play an independent role.
The man I think who really turned the tide with Lawrence was Lauritsen, down in Cal tech at that time. Lauritsen had this tandem arrangement of transformers for getting a high voltage, and it was he, I think, who persuaded Lawrence in the end. You see, what Lawrence did was to ask Tuve to repeat these experiments and see what he got. But I wouldn't say that Tuve played an important role, because his results didn't come until after Lauritsen had really persuaded —
— yes, I think they supported Lauritsen. The chronology of that —
Well, the only way to get the chronology right is to look at the correspondence.
Yes, I have all the pieces of it, I haven't studied it yet. I have the pieces of it from Cockcroft's side, and I talked with Tuve. I have it from Lauritsen's side — I talked with Lauritsen as a matter of fact a number of years ago. So what you’re saying here is that the pressure of results from outside wasn't too significant at this stage, because the only large scale work going on was at Berkeley. Does this explain somewhat Rutherford's attitude toward the cyclotron? Throughout this period he shows no real interest in it.
No. You see, first of all, he felt that the important thing to do was to establish what was happening to the light elements, and establish it accurately and tie the thing up in a bundle so that there was no doubt about it at all. He thought that the cyclotron with its high energy would get you into even greater difficulties than were experienced by Cockcroft and Walton in interpretation — and indeed it did. The cyclotron turned out to be not a very good instrument at all for direct observation of the energies involved in transformations. Where the cyclotron came into its own was in the making of radioactive materials, and in the study of those transformations which resulted in the production of radioactive materials. And there, of course, it was on its own. In Berkeley they very rapidly exploited that side of the thing, and with some wise chaps there like Ed McMillan and so on, who were wiser in their approach to the subject than Ernest Lawrence was.
Yet one could visualize these other uses of the cyclotron as a very interesting physics instrument, and there was no feeling on the part of Rutherford, on long-range planning?
Rutherford disliked complicated equipment. Held done all his early work, all the work of significance, with the simplest sort of apparatus. He disliked having any responsibility also for the spending of large sums of money. He felt this was a great responsibility that he wasn't prepared to take. He found it even difficult at times to justify the expenditure of money, say, on Cockcroft's transformer, which was 500 pounds at that time. It would cost a lot more nowadays.
The money did come from a university grant and from DSIR?
And you're saying that this was uncomfortable for him.
Yes. He didn't like the responsibility. One of the things that he hated was to have to report, to be responsible for the expenditure of money, in terms of reports on how it had been used and so on. He liked just to make his own decisions, quiet decisions as to what the money was spent on, and be answerable to nobody. It was a twofold aspect of Rutherford's character. First of all, I think he was essentially a very modest man. He just didn't feel that he could justify expenditure of large sums of money. But secondly, I think also he felt, and here I think with some justification, that too much technology around you could confuse the issues of what one was looking for. Of course, this was before the days when one recognized the fact that one had to have two sorts of people — the physicist technologist to make accelerators and make them work and so on, and the user. This hadn't occurred to him. But if you read a paper like his — what was the name of the address?
There was one to the Royal Society in the early thirties.
No, not Royal Society. This was a paper given to some organization.
British Association? [Pause to look at papers.]
No. In the Norman Lockyer Lecture for 1936, he discussed the whole question of the relationship. Really he was talking about something that's now become very fashionable, the relation between science and society, and between science and technological advance. So he wasn't blind to these things, but he disliked himself being tangled up in them. In the end he gave way of course and he allowed Cockcroft to build a cyclotron.
Had he been under pressure for a period of time prior to that?
A little, for a short period of time.
Chadwick had left Cambridge of course, because he realized that one had to go into the field of big machines, and it was largely because Rutherford was not interested in this that Chadwick went to Liverpool, where he had the opportunity to do something.
Yes, he explained that to me. But as soon as he left, Rutherford began to get involved through Cockcroft in the cyclotron.
Through Cockcroft, yes, that's right.
Do you have any recollection of how that finally came to be, after this attitude of Rutherford's, which you explained?
Well, then some money became available. This was the point; you see, first of all, the bequest or rather the gift by Austin. He gave a large sum of money to the laboratory, and Rutherford — here again it shows his modesty — believed that if one was going to build a new part of the Cavendish, it shouldn't be designed as he wanted, he was getting towards the end of his time. He felt that he shouldn't compromise the situation for his successor. So he turned the design of the new wing of the Cavendish over more or less to Cockcroft and Dee and a few others, because they were younger and more involved in the future. And I think it was partly because at that stage Cockcroft pushed the cyclotron that it actually came into being.
Did you know anything of the origin of the Austin gift? I've seen a letter published in the UNIVERSITY REPORTER where he said in a general way that science benefits industry and so forth, but do you know anything that led up to it?
No, I don't.
I know that Baldwin played a role in it, but I was curious what role Rutherford played, because this was the first time a large gift…
There had been an appeal, you see, and you’ve seen the brochure that Eddington wrote.
I'm not sure I have.
Haven't you? You should get hold of it. It's in the Cavendish. Eddington wrote a brochure which was sent out to a large number of people, and I imagine that that was the way that Austin heard about it — an appeal for money for the Cavendish.
I must look at that. So the cyclotron came about because of the availability of means to expand the entire Laboratory.
And because, of course, Cockcroft was willing to take full responsibility for it.
Well, it's interesting that it's within six months of Chadwick's leaving that the cyclotron developments get under way at Cambridge.
Yes. I think that Rutherford was not unaffected by Chadwick's leaving. He was upset by it, I know, although he understood Chadwick's reasons for going. Rutherford was very strange in that sort of way. The people whom he was close to, he didn't like them leaving. He didn't like it when I left. I was very upset about this because it was the year he died. The dean of the [Birmingham] faculty of science came across to Cambridge and saw Rutherford — a man named Moss who was a professor of mining engineering — and Rutherford sent him to talk to me. I thought this was significant, that Rutherford was thinking perhaps that I ought to consider such a job. So I went across to Birmingham and had a look around, and although there was very little in the way of facilities there, I was rather attracted by the promises that were made to me and by the people that I would have as colleagues. So I went and told Rutherford that I was interested, thought I would go, and he was terribly angry with me. It was the first time I’d ever been on the receiving end of his anger. Of course within a few moments he was most contrite, as he always was. He always apologized for being angry. It was one of the lovable characteristics of him. I left his room and went to my room feeling dreadful. A few minutes later he came to the door and said, "Uh, uh" — by that time he was calling me by my Christian name — "Can you come up and have a talk?" So I went back to his office. He apologized very contritely for having been so ill-tempered, and we began to talk about how he could help me get going in Birmingham and so on. But I think he did feel it when people who were close to him left. I'm quite sure he felt Chadwick's going, and I understood the reasons. So this I think was partly an influence on him. But I think the main influence was the availability of money and the fact that Cockcroft was prepared to take full responsibility, that he, Rutherford, would not be responsible.
In fact the next stage of the story has Cockcroft in very close association with other people working on cyclotron projects elsewhere, almost a cooperative venture.
It was. It was done in that sort of way. Unfortunately, both his cyclotron, and the one that was built at the same time for Chadwick in Liverpool, made just about every mistake it was possible to make in cyclotron design. It was unfortunate in many ways. I think they should have taken much more notice of Lawrence and much less notice of other people and in particular much less notice of Metropolitan Vickers. You see, what they did was to have far too small a magnetic gap, for instance, in order to be economical in steel, so that it was a very difficult job to get any decent voltage on across the dees. This was one of the things that Lawrence emphasized, that you must spend money on your magnet — if you wanted to get a decent cyclotron, have a good big gap.
In each case they had a Berkeley-trained man working with them. Didn't Chadwick have Kinsey?
Yes, but Kinsey had never worked on the cyclotron in Berkeley. Kinsey worked on a linear accelerator which had been thought of by Lawrence and Sloan. It was Lawrence and Sloan's linear accelerator that he worked on, for the acceleration of mercury ions. Kinsey never worked on the cyclotron.
I assumed, since he was fresh from Berkeley and came to Liverpool to work on the cyclotron, that he'd had experience with it. But Chadwick had available to him —
Of course, the design was fixed by the time Kinsey turned up.
Walk was working on the thing also.
Walk. He died in an accident.
Yes, that's right.
But Hurst was at the Cavendish to work with Cockcroft, and held worked on the cyclotron.
Yes, held worked on the cyclotron, but he hadn’t done any cyclotron design.
But then — let me probe this — Cooksey was making available every shred of paper.
I know he was. But not sufficient notice was taken of some of these fundamental facts. This was no fault of anybody's. All I mean is that in the end they didn’t turn out to have a first class cyclotron. It was always in the second rank of cyclotrons that were built in the world. At about the same time, I think it was Joliot, wasn't he building a cyclotron at that time?
Yes, and Paxton was there from Berkeley to help.
Yes. He did a much better job, in terms of the design parameters that he allowed himself.
It wasn’t a question with the Cambridge cyclotron of the magnet being wanted for multiple uses? For other kinds of experimentation in addition to cyclotron work?
I don't think that was it. I don't know. Somebody may have written in a paper, arguing for the obtaining of the cyclotron, that the magnet would be useful for, say, cosmic ray work or focusing of particles or something, but you know the way one shoves these things — I'm quite sure it was done without any serious thought. I think the feeling was that if the cyclotron proved to be a flop, the magnet would be useful for these other purposes, more than that it would have multiple uses, because it was never used for anything else.
One of the arguments that was used in other places for cyclotrons was its possible application in medical-biological research, through the production of artificial radioactive isotopes. To your knowledge was that used in the Cavendish?
I don't think so.
The only instance I know of was a medical cyclotron being planned in London, that was toward 1938, 1939.
Oh, that was much later really.
When did you get started on the cyclotron project?
In Birmingham? I went to Berkeley in 1938 and got the full designs for the 50-inch cyclotron from the Crocker Laboratory. I made a lot of modifications, including such things as air cooling on the magnet, instead of the oil cooling that they had, and a different design for the vacuum box and the dee stems. But these were trivial things in terms of principle. They were important technologically but not in terms of principle.
On that trip — you apparently left about December 10 and came back sometime in January — this is on the basis of the letters I've seen — you visited Berkeley, Caltech, Rochester, Columbia — anywhere else?
You probably know more than I do.
I'm curious about this time period, because this is the time, right after Rutherford's death and the succession of Bragg to Rutherford's position.
I'm curious as to the general picture of nuclear physics then and what your opinion of it was, while you were exposed to these thriving activities in the U.S.
My history, which I've said something about, made me extremely interested in the medical applications of the cyclotron. I've always taken an interest in John Lawrence, Ernest Lawrence's brother. He's a great friend of mine, and because of mutual interest in these things, we cooked up quite a ton of stuff together when I was building the cyclotron in Birmingham. Then of course it all got stopped by the war. We used the cyclotron to try and separate the isotopes of uranium. So it wasn't until after the war that it was completed as a cyclotron.
Let me ask about that trip. Was the purpose of the trip to get information on cyclotrons?
Then that means that you had taken a decision earlier. I’d like to know somewhat the outline of the stages of why you took the decision, how then you had to get support for it, where the support came from?
No, it went the other way, you see. I knew that whatever I was going to do in Birmingham, I had to have money. I got in touch with various people, and finally got a sum of money out of a motor car manufacturer, Nuffield, which was only 60,000 pounds, but in those days that was quite a sum of money. And I decided then, after I found how much I was able to squeeze out of Nuffield and did some sums on the cost of steel, copper and one thing and another, that I could build a cyclotron of such and such a size.
Was the gift specifically for a cyclotron?
No. The gift was just to establish me in work there following up what I’d been doing in Cambridge. I was going to work in that field, you see, but if I hadn’t been able to get enough money for a decent-sized cyclotron, I’d made up my mind I was going in for a Van de Graaff generator.
Did you use any arguments regarding possible applications of this?
Oh yes. As I say, I’ve always been keen on the medical side, and I did use that. There’s a flourishing medical school in Birmingham where I hoped to get a good deal of cooperation. In addition to that, there was a Czechoslovakian radiologist who was a victim of Nazi oppression who came and joined me in Birmingham, specifically to develop the medical side of that cyclotron.
What’s his name?
You know, I’ve got a terrible memory for names — Lowbeer. He stayed with me until the war broke out, and then when the war broke out of course we couldn’t give any time to this sort of thing. So he went off to San Francisco and became a radiologist in the hospital there, where he did very good work. He worked with Stone, who developed a lot of the medical applications of these things. Lowbeer died, unfortunately. But he was going to do this. So there was a very definite involvement in the medical side in planning the whole thing.
When was that planning stage? What date?
So within six months of your arrival there —
Yes. I got this money out of Nuffield, and the university fiddled with it for a bit. The pro-chancellor, as he was called — I’ve forgotten his name, he was the head of the Cadbury Chocolate place — after I got the money and Nuffield wrote to the university, this fellow wrote to the university saying, "Look, instead of giving it for Professor Oliphant’s use as he said in his gift, wouldn’t he give it to the university for general purposes?” Because the university had a lot of things that it wanted to spend money on, you see. This so infuriated the faculty of science, to whom this was reported at once, that they raised a terrific row and the man had to leave the university, had to get out. It was a very unfortunate development. This put a little grit in the works just for a few weeks in the beginning. But as soon as the gift was firm and the university had the money, I went along to the then vice-chancellor and asked him whether he would give me permission to spend some of the money on a trip to the United States, and he was agreeable.
That trip then was December of 1938. How far had your plans progressed by the time you left for the US?
By the time I’d left for the United States, I'd made up my mind that it was going to be a cyclotron. I did the necessary sums and decided that it could be a cyclotron of about 60 inches in diameter, and this of course meant that the Crocker cyclotron [in Berkeley], which was being built at that time, was a thing that I should study most deeply.
That was the biggest in the world at the time, wasn’t it?
That's right, yes.
And your 60-inch plan would have been bigger than anything else in Britain.
Yes. It was a bit more than 60, about 62 inches as it worked out in the end, but that was just an accident. We worked very hard on the design of that when I got back, and of course in those days one had very little in the way of technical assistance for anything. One had to do these jobs oneself from the drawing board on, the sort of thing I’d never had any experience with. But they were very good to me at Berkeley. They just handed over to me, you know, everything — plans, drawings, the sort of reports that had been written in favor of the 60-inch choice and so on — so that I was in a position to go ahead pretty well. Having seen what people like Dunning and so on were doing at Columbia, and what was going on in these other centers that I visited — you know, by comparing notes and finding in the end that undoubtedly Berkeley knew more about cyclotron design than anybody else, I was able to go ahead without too much difficulty. But after the war when the cyclotron was completed, of course we made [changes] once again, as a result of subsequent experience with the Crocker cyclotron in particular. I kept very closely in touch with that during the war, because that was being used for making materials which were important in the [Manhattan] project. Since I was living next door to it in the laboratory with Lawrence, it was possible for me to find out what all the snags were, what difficulties had been experienced, so that when we did complete the cyclotron I was able to take note of this.
On the visit to Berkeley, you commented in a letter to Cockcroft that you felt the center of nuclear physics had shifted to the U.S. I gather there were two major reasons. One was that you were so impressed with what you saw, in terms of facilities and work, and the other is the change of focus of the Cavendish.
This is right, yes. It was a great disappointment to many of us that the Cavendish threw up the sponge. See, people who had joined the Cavendish specifically to work in nuclear physics, like Frisch, you see, were left really rather high and dry. If it had been anybody but Frisch, who's such a kindly sort of person, I think there would have been a hell of a row. In fact, Bragg and Mott got their own way. It practically disappeared from the Cavendish.
What you're saying is that if a director who was in nuclear physics or was concerned with it had been appointed, the Cavendish would have continued?
Yes, I think so. I think a great mistake was made that Chadwick wasn't appointed. Chadwick was the obvious man.
Why do you think that didn't happen? I know it's difficult to speculate.
Don't know. I think the committee, you know, what are they called —
Yes, it's not called the selection committee here; it's called by some other much more high sounding name.
The Board or something like that?
No, the Syndicate, that's it. It had a lot of people on it, you see, who were concerned with other branches of physics, and to be quite frank, who were jealous of the Cavendish and what Rutherford had built, its standing as a laboratory in nuclear physics. I think that the nuclear physics there was to some extent deliberately swept under the mat.
I have a list of the people who were on the board at the time, it was published. I don't know if it was exactly that group who would be responsible for the selection but Fowler and Darwin were on it.
Oh yes — that's right, I know, but you see, Darwin was the sort of man who would believe one thing — I don't know whether you ever knew him?
Darwin was a very nice fellow and a very able man, but Darwin was a rich man who never had to work for his living. He held jobs at various times but simply for the interest of the job. And Darwin's interests would switch overnight, from one part of physics to another, you know. You could never rely on him to have any continuity of interest. I think it was a sad business. But still, it's no good crying over spilt milk. It was done.
How could a new director, even without a personal interest in nuclear physics, have continued the work? I'm not quite sure why it died out — was it a question of lack of resources, or resources being diverted to other subjects?
Resources diverted to other subjects, and other subjects that didn't command the same sort of money. You see, after the war it was possible here, just as in the United States, to get almost anything one wanted for nuclear physics. And if there had been a successor like Chadwick to Rutherford, or Blackett, either one of those, he could have got virtually whatever he wanted for the Cavendish.
That period was only a year and a half or so before the war, actually, from the time the successor was appointed to the beginning of the war — by that time the Austin wing, the Austin Laboratory was not even completed.
It was completed after war began. It's very amusing, at the opening of the Austin wing — I came across from Birmingham for it — it was opened by Sir John Anderson, then Lord President of the Council, who was a man who had been an applied scientist in his youth, supposed to know something about these things. And in his words of opening the laboratory, he referred to "this great science which had been developed in the Cavendish Laboratory of Nuclear Physics, now, I understand, called Electronics.” (laughter)
That's fantastic. Did it go into the published account of his talk, do you know?
Oh, if so, I imagine it was corrected. But I’m quite sure the decision was made and nothing could alter it.
And you felt then perhaps somewhat even more justified in what you were doing at Birmingham by building up a separate center which had nuclear physics as its focus.
Yes, especially as Peierls agreed to come as head of the theoretical physics group.
Talking about the focus of a laboratory, I’ve seen references (and Chadwick told me this too) to the criticism that Rutherford was subjected to on occasion, perhaps by Royal Society colleagues, on the emphasis of the Cavendish on nuclear physics at a time, I gather in the late 1920s, when it wasn't as productive or exciting as it became later. Do you know anything of this?
Oh yes, Rutherford often talked to me about it. I’ve got quite a bit about it here. [Looking at papers.]
I’d like to be filled in on this because I think it’s very significant, to see what the basis of the criticism was and what his response to it was.
Well, I can just tell you. I’ve got it down here. It’s very short, shall I just read this?
Yes, of course.
"For seven years, until his death, Rutherford was chairman of the Advisory Council of the Department of Scientific and Industrial Research. I often met him at the railway station in Cambridge after a trip to London and drove him to Newnham Cottage, sometimes in the evening following a meeting of that Council. He always had something to say about the work of the day. On one occasion, if I remember rightly, in 1931, he was very quiet when he got into the car, and when I asked whether the day had gone well, he said that he was worried because members of Council had again attacked him for not relating the work of the Cavendish more closely to the industrial needs of the nation. Moreover, he had been accused of producing research workers who were of little or no use when faced with real I problems. On a later such occasion, in about 1935, when he thought that any misgivings should have been laid to rest through Chadwick's discovery of the neutron and Cockcroft and Walton's demonstration of transformations produced by artificially accelerated particles, he said, “They've been at me again, implying that I am misusing gifted young men in the Cavendish to transform them into scientists chasing useless knowledge.” Rutherford's spirits soon recovered, He realized, more than most, the importance of the application of scientific knowledge if Britain was to prosper, but he remained convinced that one of the best training grounds for physicists was the sort of fundamental science pursued in the Cavendish. His faith was demonstrated dramatically after his death, when the needs of war found almost all the men whom he had trained leading such practical developments as radar, atomic energy and operational research. There it is in a nutshell.
Precisely. Let me ask about that. You're saying here that the criticism was on the grounds of exclusive devotion to fundamental research, and it wasn't so much criticism of nuclear research as a specific field within fundamental research. In other words, I had the impression —
No. I don't think he would have been criticized if he'd been working in so I’d state physics or something even though it was fundamental so I’d state stuff. It was because this stuff seemed to everybody to be so utterly useless.
Did he feel a sense of responsibility for the field of nuclear physics in general? I get the impression that he felt that the laboratory had been a pioneer in the field and had set very high standards, and he was very much concerned when he saw work elsewhere not meeting those standards. Was it any of his feeling of responsibility that it was necessary to maintain nuclear physics in the Cavendish in order to keep it going?
No, no, not at all. No, Rutherford wasn't that sort of man. Rutherford never worried about what other people were doing. What he worried about was what he and his boys, as he always called them, in the laboratory should be doing. And he felt that no branch of physics was so interesting as the actual constitution of matter, the unraveling of the constitution of matter. And he used to say, “Well, you know, such things as determining the crystal structure of a new crystal — they can be left for boys who can't think of anything else to do.” This was what he used to say, that measurement as such, without some specific reason for doing so, never appealed to him at all. He used sometimes to say held never done an experiment with better accuracy than 20 percent in his life —which was quite untrue. But it was this sort of feeling that he had. He also dinned it into the people who were working in the laboratory, you see, that they had to have a feeling of what he called "order of magnitude," He used to ask research students whom he was examining for a PhD degree, for instance, what was the resistance of a bit of wire. They'd say, "What sort of wire, sir?" "Any old bit of wire," held say. Well, what he wanted to know was whether a man said, a tenth or a hundredth of an ohm, or whether he said something absurd one way or the other. And he would ask, "What’s the inductance of a wedding ring?" or some absurd thing like that, where he wanted to get the idea that the person knew something about the relationship between dimensions and these quantities. He said, "If you can get this dinned into a man he never makes absurd mistakes." He never came out with absurd answers, because his feeling would relate one thing to another in a natural way and he would never be satisfied with an absurd relationship.
What you’re saying implies that he was very much concerned with the training function, the teaching function.
Oh, very much so. With teaching being, in the sense that I mentioned earlier, through apprenticeship.
Yes, but did he feel that it was the function of the Cavendish to play an important teaching role in experimental physics on an international basis?
Oh yes. He had this feeling very strongly. And you know, the work of the lab wasn't confined entirely to radioactivity, by any means. A lot of other things went on. When I first went there I worked with positive ions. Aston was working; J. J. Thomson was still at work in the laboratory.
Appleton was working.
Appleton and Ratcliffe and so on, and there was a chap named Watson I remember came down from Edinburgh, who'd been working on the J-phenomenon, you know, this non-existent phenomenon. He was very anxious to do an experiment to show whether there is any effect of an electromagnetic field on light, on electromagnetic waves. Rutherford told him he was wasting his time, but nevertheless encouraged him to do it, which is the sort of man he was. If a man wanted to do something, Rutherford always said that there was nobody who could choose what a man was going to do like the man himself. He was so happy in his own choice of field of work, so immersed in it, that he felt that other people should have the same opportunity to choose their line of work. He said, "Nobody else can ever choose it for you.”
Did he feel a special responsibility toward the Commonwealth in terms of taking in a large number of research students from New Zealand, Australia, and Canada?
Well, both he and Chadwick had this feeling, and Chadwick has remarked to me that when he came to Cambridge with Rutherford, and they were talking over the way the lab should be run, he suggested to Rutherford that it might be a good idea to have a definite intake of six or seven people from the Dominions each year, to reserve places for them. He said Rutherford was extremely happy that held thought of it, because it was very much in Rutherford's own mind. He felt this very strongly. I’m sure it's the only way I ever got in.
I did a study of the PhD's produced in Cambridge from 1925 to 1940, and more than 50 percent were from the Dominions, with the greatest number being Canada, New Zealand and Australia. If you like I can send you those breakdowns.
Yes, it would be interesting.
I want to find out how much time you have left.
I have none left. I’ve got to walk around to Chadwick's — I said I’d be there about a quarter to 1. Let's say twelve got 10 minutes.
Oh, then I can cover a few points. One was the nature of your specific duties as the assistant director of research from October, 1935 to the time you left in 1936.
Here again I can tell you a story. Rutherford called me in when Chadwick left, and held made this decision. Charlie Ellis of course was also an assistant director of research at the same time. Rutherford called me in and he talked to me for about a quarter of an hour or so, about the problem of choosing subjects of research, specific lines of research for research students which were likely to be productive in two or three years, and give the man a chance to get a PhD degree. Then he suddenly said, "But you know, there's something much more important than that.” I said, "What’s that, Professor?" He said, "Knowing when to stop.” And he went on to talk to me about the number of dead horses that were being flogged in various parts of the world, including the Cavendish itself where one or two obstinate people he felt were working on things that didn't justify further effort. This has stuck in my mind ever since. And I realize that this is an extremely important thing, not only for a laboratory like the Cavendish but for institutions, national standards laboratories and all these sorts of things. When I got to visit these places, one of the things I noticed is how right Rutherford was, how many people in these places are working on things that don't really justify further efforts. It's still worse in the laboratories associated with the Navy, the Army, the Air Force, where you find men doing work which is really like 1940 work, and the only reason is because they've been doing it all their lives.
There's an interesting talk that Corbino in Italy gave in 1929, addressing himself to that same question — it's going to be translated and published, and I'll try to get a copy for you, because he talked about the need to switch fields and subjects. But this was your orientation as assistant director of research. How did that affect your regular routine?
Well, I had to spend more time in talking to other people about their work and seeing to their needs, trying to provide the equipment they wanted and one thing and another. Of course, I got caught up also first of all, in the million-volt unit from Philips and then the two million volt unit.
You visited Philips in 1934-35 for an observation, in connection with that?
That's right, yes.
So you were in charge then of bringing in and supervising some of the new installations?
Yes. It was wholly my job, the Philips, the first one, and then the second one of course, Dee was in on that and took over from me.
The first one was completed before you left in '37?
Oh yes, we'd got a lot of work with it before I left, a lot of work with it.
How did you find your research time affected by these new responsibilities?
It was cut down a bit, but not all that amount. I found that I learned more from other people than I'd learned previously from other people. This was one of the compensating features.
This was pretty much the story till you went to Birmingham.
You would presumably have continued in that position, had you not been invited to apply at Birmingham.
I wasn't invited to apply, I was invited to accept: If they'd done that I'm sure I would never have gone. I wouldn't have applied, I'm quite sure of that. Quite sure that it was just the fact that the job was offered to me that made me go at all. I was just too devoted to the Cavendish and Rutherford to have considered any move — under any other circumstances — no matter where it was.
Well, we have very little time left, but let me ask — on the U.S. trip in December 1938 and January 1939, had the fission discussion broken at that time, while you were there?
I don’t think it had become —
It depends when you left in January, 1939, because it was in January 1939 that the discussions were held.
No, I can remember talking to people about it, you know, this thing, but I don't think it had produced any great result in peoples general thinking at that time. Because you see, it wasn’t really until Frisch and Meitner showed that the energy was so big, and then Joliot showed that neutrons were emitted, that it became obvious to everybody that this chain reaction was on the doorstep.
I mean even before that, just the announcement of fission, Bohr’s appearance in the U.S. and the word coming out — were you there at that time? Do you remember any repercussions at that time?
I don't remember any. What I remember is coming back and coming across to the Cavendish. They had set up a fission experiment to show that the energies were what they were and so on, and Frisch, who had joined me in Birmingham, doing a very simple experiment, as Frisch's experiments always were, to demonstrate fission, with just a little bit of uranium perched on the grid of a vacuum tube. Of course, the ionization was big enough to show up even on an ordinary tube.
That was when Frisch and Peierls and the memorandum, and everything got rolling.
Well, not until a while after that.
 J. Chadwick, "Some Personal Notes on the Search for the Neutron," in International Congress of the History of Science, 10th, Ithaca, N.Y., 1962 (Paris: 1964)
 Department of Scientific and Industrial Research
 Quoted from Oliphant, RUTHERFORD: RECOLLECTIONS OF THE CAMBRIDGE DAYS (Amsterdam: Elsevier, 1972), pp. 145-146