Egon Orowan

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ORAL HISTORIES
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Interviewed by
S. T. Keith
Interview date
Location
Belmont, Massachusetts
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Interview of Egon Orowan by S. T. Keith on 1981 October 4, Niels Bohr Library & Archives, American Institute of Physics, College Park, MD USA, www.aip.org/history-programs/niels-bohr-library/oral-histories/31787

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Abstract

Topics discussed include: his early education, Walter Elsasser, his work with metal crystals, Richard Becker, his work with krypton and lamps, theory of dislocations, his time at Cambridge University, recrystallization, and x-ray crystallography.

Transcript

Keith:

Dr. Orowan, I know you were born in Hungary, in Budapest. Are there any particular memories of your childhood that stand opt, that you can remember distinctly, which may be influenced your future career?

Orowan:

Well, the one thing that influenced it is that when I was 12, I was playing football and I was goalkeeper, with big grownups, and one of the balls hit my hand eccentrically and broke my wrist. That was on the day before the end of the school year, so when we went to vacation, to the countryside, I could not play games, and my father gave me his camera and supplied me with material for that, which was very exciting because I didn't know anything about it. So when we returned I remember I had no time to take off my overcoat; I had to rush to the encyclopedia and look up what the different chemicals were. A few days or weeks later, I had a little chemical laboratory, so that was chemistry then. I still have a book of Ostwald from that time. And after that came physics and so on.

Keith:

What kinds of experiments would you be doing with your chemistry set?

Orowan:

Oh, the same old things, precipitating this and that, interesting colors, not very exciting or not very intellectual things.

Keith:

Yes, but it's science for youth.

Orowan:

Yes. If somebody asked me later, I mean, fairly recently, which was the most useful subject in the secondary schools, so I had to reply, which was the truth, that the most useful thing in the secondary school were the so called cholera vacations, during the First World War, because then I had three or four weeks at home without having to worry about things.

Keith:

So you don’t think you really got much out of school?

Orowan:

Perhaps. Very very difficult to track the indirect processes. But I think that the most beneficial thing I experienced was that 1 broke my wrist.

Keith:

Did you actually do any science in secondary school?

Orowan:

Yes. We had chemistry when I was 15, and physics at 17 and 18.

Keith:

What kinds of subjects would you be doing in physics at that time?

Orowan:

Physics, as a whole.

Keith:

Yes. Would it include any of what were there the new ideas of atomic physics?

Orowan:

No, it did not, but we had an official club in which once every week. Students, I mean pupils, submitted poems or recited and so on. My father subscribed to the periodical of the Federation of German Engineers, and there I found an article by Sommerfeld, from 1916, on the new Bohr Theory, and that became the first lecture I gave in that club.

Keith:

How old would you have been then, about 16, 17?

Orowan:

15 or 16. I remember at 14 we were entitled to listen but not to submit.

Keith:

Were there any actual experiments you were able to do at school, or was it all the traditional demonstrations by the teacher?

Orowan:

No, no. Just demonstrations.

Keith:

Could you tell me a little about your father? If believe your father was an engineer?

Orowan:

Yes.

Keith:

So he must have had some influence on you. You've already said that you had these various things around the house?

Orowan:

Yes. It would be difficult to trace the points of influence, but he had of course books, and I was in close contact. Every second Sunday, he took me to the factory and to see the two engine rooms, which was a great treat.

Keith:

What was the factory he worked in? What kind of factory was it?

Orowan:

That factory produced sulfuric acid, nitric acid, hydrochloric acid, and phosphates, fertilizers, and a few more chemicals.

Keith:

So your father was a chemical engineer?

Orowan:

No, he was a mechanical engineer. He designed, for instance, even the buildings for the big chambers. At that time, sulfuric acid was made not by the catalytic process, but by the chamber process, and those were placed in huge wooden buildings. He liked very much to design these buildings of wood, very big ones.

Keith:

Did he have any particular ideas about how he would have liked your career to develop?

Orowan:

How he would like it?

Keith:

Did he actually tell you what kind of job he would have liked you to have had?

Orowan:

Very naturally, mechanical engineer. And I didn't quite like it. So I started with chemistry. One year.

Keith:

This was at the University of Vienna?

Orowan:

Vienna. And then the next year was astronomy, and something else, and then he became energetic. One of his good friends from school was then dean of the department of mechanical engineering in Charlottenburg and it was very difficult for foreigners to get in, but if he squeezed me in —

Keith:

Yes. So why did you shift between these subjects at Vienna? Why did you change from chemistry to astronomy?

Orowan:

From chemistry because the first year in chemistry was qualitative analysis and mostly things I knew well from the time when I was 13 and 14. So it was dull.

Keith:

Why astronomy, then?

Orowan:

It’s very different from chemistry.

Keith:

Yes? So you went to Vienna in 1920. You left there in 1922 after two years.

Orowan:

Yes.

Keith:

What actually made you decide to go to Vienna to start with? Was there any particular reason?

Orowan:

Well, you know, it was difficult to get into a foreign university, unless you were either from Afghanistan or from Egypt or from any other state that placed big orders with the Germans. But in Vienna, my father studied in Vienna, and so he knew the friends or brothers of friends who were professors there and could help me.

Keith:

Did your parents finance you at university?

Orowan:

Yes.

Keith:

So when you went to Berlin, was that in 1922?

Orowan:

1923, because in Berlin, even to begin the study of engineering you had to have at least six months of workshop practice. I couldn't get a place in any of the German factories because I was not from Afghanistan or Egypt, so I had to go home and I did my six months of apprenticeship in the Hungarian state local waterworks, where my father had his first job in life. So that was six months, and after that I went to Berlin.

Keith:

Did you enjoy this experience in the engineering works?

Orowan:

I would have enjoyed it very much if it hadn't been cold.

Keith:

What about the work itself; did you enjoy the work you were doing?

Orowan:

Oh, of course. It is not very exciting, but it is very interesting nevertheless.

Keith:

It seems to me; by this time in your career you were building up a fairly liberal education, in so many subjects. Do you think that influenced you for the rest of your life, for the rest of your career? I mean, time and time again since then, you've moved into different areas.

Orowan:

That is very difficult to say. I would say that what I am doing now, for instance, comes from my first year in a.... Berlin, because I lived in a furnished apartment, together with a friend of mine who had plenty of money, and he immediately bought Spengler's book, you know, THE DECLINE OF THE WEST, which I immediately tried to read. And for a number of years, I did not know whether Spengler was silly or I was silly. Well, here really, the deciding point came around '46. The junior fellow at Caius College, who preceded me, was anything but a junior man. He was not far from retiring age. He was R. A. Fisher, the geneticist and mathematician, and it turned out that he had the same hobby at I had. And he enlightened me, which the outstanding man in this field was not Spengler and not Toynbee, but Ian Cardoon(?) and so, about 18 years ago, I started to put it together. Then I realized that without economics, it just didn't work. Then I realized that, to put in the sections on economics needed at that point would have made it very awkward, so I started to write the necessary preliminaries of economics separately. Then I realized that economics, in the present sense of the word, does not exist at all, which, however, did not mean that it was not necessary to do anything about it. And this is what I am still doing. I hope to finish it now, soon enough.

Keith:

Yes. So it's your main thesis, within this book you're doing at present?

Orowan:

That I think will be the most urgent thing I have been doing, because it is a very unfortunate thing that, whereas the cause of the present troubles in the world was very clear to cleverer men 50 years ago, the first man who wrote exactly about it was Einstein. But strangely, it has never penetrated into economics.

Keith:

So what are the major ideas behind this thing?

Orowan:

Behind this?

Keith:

Behind your ideas at present?

Orowan:

Well, it is mainly what was the cause of the breakdown in 1929. At that time, or two or three years later, every intelligent person knew it was very simply that machines were doing the work that men were doing earlier, and they didn't solve the problem of what to do with the displaced workers. And, of course, that this was the cause of the collapse in '29 was known as I said to Einstein in '34, “My mother told me in '32.” But it was strictly taboo in economies, because if their productivity could exist, then economics could not exist, because the purpose of classical old fashioned economics was to increase the wealth of nations. And if the wealth of nations was disastrously high, then economics, in the old sense of the word, had nothing to do. So the economics of Smith, Ricardo, Marx, Keynes, all aimed at something that was long ago over-shot.

Keith:

Yes. So you're saying essentially, that modern economics has no room for technology.

Orowan:

No. On the contrary, a right, a correct economics has to adapt itself to technology. That means, the trouble is that if there are cakes in the pantry, the little boy, if he can go in, he may eat it all up, upset his stomach. The responsibility for that is not the cake's, but the lack of supervision or control, and it is exactly the same today. It is not the technology that is responsible, but the lack of understanding of what happens, that technology can produce immensely more than the society can consume without suffering a stroke or a heart attack.

Keith:

Yes. So it's across the board production.

Orowan:

Yes. Today's economics starts from the wrong premises. And then argues, very ingeniously that as you know, the computer people express it by saying that "Garbage In, Garbage Out".

Keith:

Yes. Maybe we can talk about this more later. I think we should go back to earlier. This famous meeting with Becker that you talk about in the Soviet Centennial Conference meeting — 1928 — so what did you do in between then, your period in the engineering works in Hungary, and before you?

Orowan:

I studied in Charlottenburg first mechanical engineering, then electrical engineering, and the last year was to be to design a transformer and a generator. Then I soon realized that either I can design a computer to compute and transformers and chose the best, or I shall never graduate. So, to have a little amusement, I spent a day of the week in the advanced physical laboratory, where I reproduced the Millikan experiment and similar things. There was no complication, because the professor, who was Kohlbaum, was a very good hunter, but he never came into the lab. So at the beginning and end of every semester, I had to take my sheet to the laboratory servant and he put the rubber stamp, the signature of Kohlbaum on it. But then Kohlbaum died, and next time, I went to the lab steward, he told me there is no more rubber stamp. I had to go to the deputy of Kohlbaum, who was professor of theoretical physics, and he was Becker. He was sitting in the office of Kohlbaum and asked me why I was taking the laboratory, since I was an electrical engineer. I explained it to him.

Keith:

What were the reasons you gave him for doing the experiments?

Orowan:

Oh [???] — and so I left, and fate wanted that the office was a very large room. Becker was a very shy person, and if the office had been smaller, I would have left and that would have been it, but just when I arrived at the door, he struggled through to the decision, and called me back, and asked me if I would be interested in checking experimentally a little theory, he said, which he published not long before.

Keith:

That he published in 1925.

Orowan:

Yes.

Keith:

Why do you think Becker asked you to do this? Do you have any ideas at all? Pure chance?

Orowan:

Well, I happened to be there.

Keith:

Before we talk further about Richard Becker had you made many friends during that period in Berlin? I believe you were friends with Walter Elsasser.

Orowan:

Oh yes. He's now in Baltimore, you know, and we have remained very good friends ever since.

Keith:

What were the particular circumstances that led to your becoming friends?

Orowan:

Oh, a chain of accidents. The last accident was so crazy. It is not a chain, in a chain of becoming friends, but another friend of mine asks me, why Elsasser’s role in the discovery of electron diffraction was so subdued? So I wanted to ask, to reply to that, and I went to the library, and looked up how it happened, and I must say, I would never have believed it if anybody had told me. The story was simply this. A man called Davison, with a collaborator called [?] observed those patches on the film, which were electron diffractions with nickel, published them, in the PHYSICAL REVIEW, I think, and of course had no idea of what they meant. And then Elsasser who was then an undergraduate in Gottingen published a note in the Naturewissenschaften pointing out, not only that they were likely to be electron diffraction, but he calculated the positions from the Planck relationship and the lattice of the metal, and they came out pretty well. And then, one year later I think, Davison and Germer published a paper in which they now produced the diffraction deliberately, and on the second page of the paper, they remarked that Elsasser expressed the opinion that these earlier things could be electron diffraction. Unfortunately they had to point out that this was wrong because — now, the funny thing was that the “because” was that Davison completely forgot the curves in his own paper of two or three years earlier, and what was even more curious, Elsassser has always been a very nervous man, and apparently he was so embarrassed by this statement that he was wrong, that he did not look up the earlier Davison paper, and he did not read the Davison-Germer paper. In fact, when I told him about this two or three years ago, he was very embarrassed, and he asked me not to write any remark about it. And what we even more remarkable is that — I don't know how many persons were members of the Nobel Committee which awarded the prize, but from reading those four papers, it was very obvious, not one of the Nobel Committee members had read them, because if they had looked at them, immediately they would have discovered how it came.

Keith:

So that's how you first came across Elsasser?

Orowan:

No, no, I met Elsasser I think 50 years ago or 40 years ago, but this was my last interesting experience in connection with him. It was so very interesting, because I would not have believed really that an award like that would be adjudicated without one person in the committee having read four papers.

Keith:

Yes. Do you recall any other particular friendships that you made in that period at Berlin?

Orowan:

They were largely outside my field. My narrower field.

Keith:

What were your other interests in that period besides your academic work? I mean, were you a sportsman of any kind?

Orowan:

No. Of course, we all listened to concerts and went to — there were two operas in Berlin — and it was really a unique place. We were all concerned somehow that it would not last long because it was too good.

Keith:

Yes. You lived in this period in a boarding house with other students?

Orowan:

No. There were no boarding houses there. You took a furnished room, which was difficult to imagine, but one of my friends — as a matter of fact, the one who bought the book of Spengler's — after that I lived in the apartment of a bank clerk, who had an apartment of 22 rooms, in a very modern, very fashionable district of Berlin.

Keith:

Yes. So you enjoyed that period socially.

Orowan:

Yes, socially, I would have to remember more clearly, but I enjoyed it immensely, as a period that lasted a very short time, and we knew that it would not last long and that it would never return.

Keith:

Would you say that you were a hard working student in those days?

Orowan:

No.

Keith:

You neglected some of your studies?

Orowan:

No, I would say that, since evidently I felt I did not have the power for strenuous work, somehow subconsciously I specialized in being lazy, and doing things for which laziness is needed.

Keith:

This presumably would have irritated your father a great deal.

Orowan:

No. My father was an exceptionally good, nice man. Of course, when I wrote him that Becker suggested that I should do that work and switch over to physics, he was extremely sorry, because he was convinced that you could never make a living out of physics.

Keith:

Can you tell me anything about Becker, before the time you actually met him? I know he was a student of Sommerfeld’s.

Orowan:

Yes. He told why. He was actually studying entomology, but — in Munich — he noticed one day that he was getting lazy, and so he had to do something against that. He took the catalogue of lectures, and looked up the earliest one, which was then at 7 AM, and that was a lecture by Sommerfeld. So he took that lecture of Sommerfeld as a medicine against getting lazy, and stuck there. His doctor's thesis was still within entomology. And after that, he became an employee of an explosives works in Cologne, or near Cologne. Then he went to the Ostraud — the Ostrand Incandescent Bulb Co. And then he was invited to the chair of theoretical physics at the Technical University, when Kregar Menzel retired. Now, I don't think you know Kregar Menzel's name. He was a close relative of the famous painter Menzel and because of that, he was there at the social occasions when everybody in Berlin who counted was there, and that impressed him so much that he became easily frightened, shy and retiring, and his life work was essentially the edition of the lectures of Helmholtz, whose pupil he was. So he was succeeded by Becker.

Keith:

Do you know the date when Becker first took up the professorship?

Orowan:

It wouldn't have been more than two or three years before I met him, two or three years before 1928.

Keith:

So he would have actually produced that paper in 1925, before he became professor of physics?

Orowan:

Yes. I think he produced it when he was with [???]. Actually, when I was his assistant, my first consulting job in my life was for Ostrand. In fact it was to calculate the loss of light by absorption in those gas discharge lamps, the sodium discharge lamps which are now used on streets.

Keith:

When was that? When did you have that consultancy?

Orowan:

'29, I think. Oh, that was not a job, it was just an assignment, one assignment.

Keith:

Do you know how Becker became interested in plastic deformation?

Orowan:

I think one can find that in his first or second paper.

Keith:

This paper he produced in 1925, what were the essential ideas within that paper?

Orowan:

The essential idea is this: at that time, they had, in the plasticity of metals, there were two great problems. In Germany, the problem was why metals and materials are so weak.

Keith:

— compared to the predicted strength.

Orowan:

Compared with the theoretical strength. And in London, I mean Carpenter, the problem was, why they are so strong? Because G. I. Taylor started from the assumption that, if there was no strain hardening their strength, I mean, the yield stress would be zero. So his problem was, to explain why metals and higher crystals were so weak, and what he suggested in plasticity was that the weakness was a consequence of thermal stress situations which were superposed to the applied stress, and produced yielding at a much lower stress. So what he wanted me to do is, to measure the yield stress of some metal crystals at very low temperatures, the temperature of liquid air or liquid nitrogen. Of course I spent a lot of time building that apparatus, and a week or two before, I could do my experiment, Schmidt and Meissner and Polanyi did it, and found that the thermal fluctuation hypothesis could not stand, because their crystals were practically as soft at the temperature of liquid helium as they were at room temperature.

Keith:

That was Becker's reaction to that result?

Orowan:

He was very disappointed. He was so disappointed that he spent a little time in kind of a sanatorium in Switzerland to recover from the disappointment.

Keith:

Yes, so it would be a kind of rest home.

Orowan:

And then came Hitler. And I stayed about half a year beyond that, and then I went home. And at home, I wrote down the experiments and the conclusions, sent them to Becker, and Becker was very very happy. In his reply, he said that I really did a miracle cure. Then, as you have read in that, it must have been three or four weeks after the appearance of my paper on dislocations that Taylor wrote me, that his paper on the same subject would appear soon in the [???] and that is how, I’m sure that that was in ’34. But I’m sure that just as I was writing about dislocations in ’29, that Taylor did the same in ’29. I’m sure he did.

Keith:

So he was following very much the same thought processes.

Orowan:

But from an entirely different point.

Keith:

— yes, but going towards a similar solution.

Orowan:

Yes. You know, his problem was to explain asterism. He explained, he tried to explain it by the stress field around dislocations. Then a few years later, it turned out that partly Berkeley, it was a very disappointing thing, in crystals with one set of glide planes, the main part of the asterism was due to a trivial bending, but in cubic crystals, it was not so, and in cubic crystals, I think it is not really quite put in order till recently.

Keith:

What kind of reading material would Becker point you to when you first started working for him? Griffith’s work presumably?

Orowan:

Yes, of course. Griffith was the starting point of I think, certainly one of the main starting points of Polanyi, Schmitt, Becker. Whatever was done in this field in Germany, that arose under the impression of Griffith.

Keith:

Whereabouts were Polanyi and Schmitt working?

Orowan:

In the Kaiser Wilhelm Institut fur MetalKunde, in Dahlgren which was a suburb of Berlin.

Keith:

Did you know at that time Walter Boas?

Orowan:

Yes, Boas was my predecessor as Becker's student.

Keith:

Boas presumably must have been Becker's first PH D student.

Orowan:

Yes. I think he was the first and I was the second.

Keith:

What was Becker like as a supervisor? Did he give you close supervision, or did he just give you the problem and leave you to get on with it?

Orowan:

Well, he told me that Schmitt and Polanyi worked with zinc and cadmium crystals and tin, so he asked them how to do it, and he told me, I think I got funds —

Keith:

— Yes.

Orowan:

And after that, Becker did really the most beneficial thing that can be imagined. He just never came to me and never — I went to him socially — and of course, I learned a lot from him. I listened to his class.

Keith:

What was the class he gave?

Orowan:

Theoretical physics. But he really did the best I can imagine with me.

Keith:

Yes. What's your opinion of him as a scientist, as a physicist?

Orowan:

He was extremely reasonable. I think there were very few people who understood thermodynamics as profoundly as he did. And he was a very nice person.

Keith:

Yes, very shy, as you said before.

Orowan:

Very shy, yes. Very tall and fat.

Keith:

Was he interested in magnetism in those days, or did that come later?

Orowan:

That came while I was doing the work, suddenly. Once I visited him. It was just before Christmas, on a sunny day, and when I arrived at their house, Becker was in front of the house, walking. And he greeted me by saying, "Just imagine what a Nice Christmas present I've got!" That was the idea of the relationship between magnetostriction and ferromagnetism. And then, of course, some weeks later or one or two months later, it turned out that the same idea was, came to, what was the name of the Russian? The young Russian?

Keith:

Frankl?

Orowan:

No. A very well-known name. At least it was well known.

Keith:

Oh, Akulov.

Orowan:

Akulov, yes. Actually Becker invited Akulov to give a lecture in Berlin, and Akulov was very young and very cheeky.

Keith:

How young would he have been then, twenties?

Orowan:

I think probably. Probably less than 30.

Keith:

They both published about exactly the same time, about 1934. Were there many other students of Becker's while you were there, or were you his own assistant at that time?

Orowan:

Yes. In fact, I became his assistant a few weeks after we first met. Not because I was so unusual, but because I had a class with his former assistant. And he had to have somebody to correct the home assignments.

Keith:

So, you were given the donkey work.

Orowan:

No, that was the usual work for the assistant.

Keith:

Did you see Becker at all after you left Germany?

Orowan:

Oh yes. Last time, he visited Boston, and I received him at the airport.

Keith:

That must have been the early fifties, '53?

Orowan:

Yes. His family had a very tragic fate. His son disappeared during the war in Russia. One of his sons-in-law was killed in a mountaineering accident. One of his daughters I think died early. I think Becker was 70 when he died.

Keith:

Yes. I've seen that. I remember his Festschrift that appeared just after the war, I think his 60th birthday.

Orowan:

By the way, I must have here — do you read German?

Keith:

No, but my friends read German and will help me.

Orowan:

There are probably a few words about this.

Keith:

Did Becker do much work after around 1940? Most of his work that I've seen comes before that period.

Orowan:

Yes, I think he did less after the magnetism period.

Keith:

So I think the last major thing I've seen is his book, in fact, the 1939 book on ferromagnetism.

Orowan:

Yes.

Keith:

So really would you say that his main two contributions scientifically would be his work on plastic deformation, and particularly the work on magnetism?

Orowan:

I think that, although it was not as spectacular, what he did and wrote on thermodynamics — he was so outstanding — that I would include it.

Keith:

Yes, you'd include that. When one looks at that really quite short period in his career, the thirties, there were many of his students and assistants who produced major work themselves.

Orowan:

Yes. Well, of course, a man like him has a very intense stimulating effect, which is very difficult to trace, but nevertheless it is very important.

Keith:

And, of course, Becker was Born's successor at Gottingen. You must have taken that with quite mixed feelings, one would have thought.

Orowan:

Well, it was not a nice time. He behaved as nicely as possible. It was evident, well, evident to most people there what was happening, and I don't know whether Becker regretted it or not. I think that his happiest time was in Berlin.

Keith:

Yes. Did he ever consider leaving Germany, do you know?

Orowan:

Did he? No, I'm sure not. No, he had a family.

Keith:

He was very much part of the German scientific scene.

Orowan:

Well, of course he was very unhappy about what was happening in Germany. But since he was not directly exposed, and it would have been very difficult to set up a new existence abroad — it always had, it had to have a very special reason. For instance, the first brain drain case, immediately after the war, from Britain to the United States was a direct consequence of the fact that in Britain, there were practically no retirement pensions. And so that colleague of mine came to Brooklyn because here he could work as a consultant. And I think there were others. Let me see, perhaps, I would say — I think partly including me, came to MIT because at that time, I had only 15 years before retirement, and I had no fortune, so I had to take care of the future.

Keith:

Yes. Going back to Richard Becker, are there any particular memories that stand out in your mind which reflect on his personality?

Orowan:

On Becker?

Keith:

Yes.

Orowan:

He was very, very nice and a very, very attractive man. He really was a very fine mind, so that from what he published rarely, you rarely know the full impression of his size, and capacities.

Keith:

Do you think he's under-rated as a physicist, when one looks back on the history of that period, do you think he's under-rated as a physicist, because people think of that period and think of people like Heisenberg and Pauli, and Becker's name rarely comes to the surface.

Orowan:

Yes. These things of course depend very much on accidents. And I think that Becker left Munich and went into industry probably because in Munich there was no suitable opening for him. And I think that may have decided everything. I did not — of course, later on, I was rather far from what he did. I think he died before my main publication on a subject that he was interested in would have appeared, because that was about 1970, '71, and he was not alive then. That I regretted very much indeed, because I felt he would have been amused to see it.

Keith:

Yes. Were you always on friendly terms with Becker? Did you never argue at allover issues with him, plastic deformation?

Orowan:

No. No. In fact, I listened to his lectures. The very first lecture of his I listened to was his theory of Griffith, and that was a colloquium. Of course, everything then went around Griffith, and I would have been very glad to meet him.

Keith:

Did you ever meet Griffith?

Orowan:

Yes, once, twice, but I was aware only of one. When I did meet him, that was in a committee of which we were members, and he appeared at one committee meeting, and so I met him that, on that one occasion, and I think it must have been after the war, between '45 and '50. It was before I met him in that committee meeting, that I mentioned to Taylor how sorry I was that I went to a conference in London in 1934, I hoped mainly to meet Griffith, and I didn't. Taylor opened his eyes a bit large and said, "But you were sitting next to him for a whole day!"

Keith:

Who did you actually meet at that conference that you can remember?

Orowan:

Oh, there were many, many there. I remember, of course there was Darwin there and Bragg, the two Braggs, and Slater, whom I can never forget because he had a very smart movie camera on him. And in fact, many, everybody was there.

Keith:

Was this the first major conference you'd been to?

Orowan:

Yes.

Keith:

Did you find it quite impressive?

Orowan:

I found it very pleasant and interesting.

Keith:

What I find interesting about that conference is, that particular session — because it was split into two, wasn’t it, the conference — but the session where the plastic deformation work was discussed was actually called about the solid state. Was that the term that was used very often then?

Orowan:

Yes. At that time solid state meant the mechanics of solid state. And then today of course it means electronics of solid state.

Keith:

Had it been the traditional concept for mechanical properties before the thirties? I mean does it have a long history as a label?

Orowan:

Now, should we disregard elasticity?

Keith:

Yes. I think I'm mainly talking about plastic deformation, deformation studies.

Orowan:

You know that dislocations were introduced in elasticity. And for a long time, I could not really understand how on earth it could have a mathematical solution which was used by —

Keith:

Boltzer, the Italian Volta that was used by Taylor.

Orowan:

By Taylor, used this solution that was found in this doctor's thesis by a man who was a professor, what was his name? He was professor in Berlin at the Technical University, and I have never met him; I had never even seen him.

Keith:

Oh, Pendall?

Orowan:

No. I don't think he did anything later. But I was always amazed, how on earth he could find that solution of the dislocation field, and it was only much later that I learned that the difficulty of the Italians was to get rid of the dislocations, because they thought it a singularity, so they had to add terms in order to get rid of the dislocations in elasticity. And all that, the mathematician did, whom I have in mind, was to omit that. You omit the term that was introduced to get rid of the dislocation of the singularity which was a dislocation. You can find it all in [???]’s book. That is really a very splendid book.

Keith:

Yes, I remember, in the introduction, the historical introduction.

Orowan:

Yes.

Keith:

Because I seem to remember from that account that gave in that same centennial meeting, that he'd gone to Lut(?) to find the solution for it. And quoted Balfour(?).

Orowan:

Yes, but the dislocation theory…

Keith:

This original Italian work, would elasticity at that time I would be considered very much a part of mathematics.

Orowan:

Yes.

Keith:

So it was very pure, very theoretical.

Orowan:

In non-elastic problems, I think it was Prandtl who first introduced it. I think it was to explain the crystallization, or the process of dislocation – He wrote in the Encyclopede der Mathemathesche Wissenschaften in part contributed by, as a contribution of Prandtl, where he promised there to give a complete treatment in a later publication which appeared, I don’t know, 15 years later.

Keith:

1928.

Orowan:

But it was not complete.

Keith:

Yes. But there were many other people, of course, in that period that you've quoted yourself in your — centennial paper who were thinking very much along similar lines around that period of 1928. You talk about —

Orowan:

Yes, now, who was that German who did that in '33 or '32, but he did not have in mind plastic deformation, but only recrystallization? Who was that?

Keith:

Was it Delinger?

Orowan:

Yes.

Keith:

And he was just considering recrystallization? Wasn't there a Japanese? Was it Yamaguchi?

Orowan:

That was later. Yamaguchi, I don’t have now what he did. All I remember is that his paper showed unusual ingenuity, and was it he or was it another Japanese who then disappeared from sight, as Griffiths did, and I think that he — it was not Yamaguchi — was prominent in the design of warships.

Keith:

No, I don't know.

Orowan:

It was not perhaps, some one of them, I remember.

Keith:

What do you mean by Griffith disappearing from sight?

Orowan:

Well, Griffith soon after his famous paper, I mean soon after 1934, which was his second paper, he switched over to problems of the jet engine.

Keith:

Well, of course much of his work wasn't published. Including that one paper on dislocation from the thirties, of course, which Taylor showed you during the war.

Orowan:

Yes.

Keith:

I have a copy of that paper. It’s home. I wrote off to the Royal Aircraft Establishment and they sent me it.

Orowan:

By that time, of course, I was not only really connected with this field. Above all I was more interested in geophysics. And alternating with these problems I just mentioned to you.

Keith:

That was your opinion of Taylor when you met him? I mean, this was the first time you met him, at the conference?

Orowan:

Yes. Of course you know that he was extremely nice and an extremely outstanding man.

Keith:

Yes. Again, Taylor, like a number of other people, the majority of his career wasn't in mechanical deformation studies. He only got into it through that chance meeting at the Royal Society in the twenties. I just find it unusual that he just should pick up on mechanical deformation, work in the period and then drop it.

Orowan:

— yes, asked for advice by Carpenter… so when he gave a paper on deformation, it was I think, by the three of these – Carpenter, Taylor and [???]?

Keith:

Yes. Did you ever meet Miss Elam in your period in Cambridge when she was in the engineering department?

Orowan:

Yes.

Keith:

Do you have any memories of her?

Orowan:

She was extremely nice, and she supplied us with eggs – during the war.

Keith:

She had a farm house, did she?

Orowan:

I think she had something like that.

Keith:

I think she was working on the welding of ships, steels, during the war.

Orowan:

[noise on tape makes it hard to hear and continues to end of interview] Yes. That was of course perhaps my main work in the war, in — and strangely enough, after the war, in the first doctor’s thesis here at MIT, or shortly after that, it turned out that it was all wrong, that we saw that even the [???] was completely beside the point, because it was not. I don’t know, are you interested in that?

Keith:

I've got the reprint. The one that you mention with your first, that's right, yes.

Orowan:

That was quite a shock. [???] finished it very very nicely and with great care, and the point fell exactly on the curve. Then he left for a year in Holland. Then a little later, two or three days later, I went into his laboratory, and looked at the specimen, and it turned out that it was all entirely different.

Keith:

How was it different?

Orowan:

Well, it, the brittleness of steel as a matter of fact has nothing to do, or only indirectly to do, with the stress (concentration?) at [???]. See, if it were, then in the other metals, these cracks would be brittle. But it is not. So it turned out that the brittleness in steels is an effect of the very rapid dependence of the yield stress on the rate of deformation. Exactly what they thought in 1890. But at that time, it could not be explained, how it all hung together.

Keith:

Yes. We can go back to the chronology we were going through. So you left Germany in 1933.

Orowan:

Yes.

Keith:

And you went back home for employment of some kind, you went back to Hungary for a period. In fact you worked in industry for a year?

Orowan:

Oh, it was a little more than a year.

Keith:

What was your job that you were given?

Orowan:

There was an electrical firm, the bulbs, of which were called tungsten. That was the first firm to market tungsten filament lamps. At that time, one of the men there called Brody — he was later killed by the Nazis — suggested filling the lamps with krypton. So first they bought krypton from Germany, and then they built a factory for krypton. I was in charge of that factory, and partly of the coal mine next door, because the energy consumption was so large that they bought a coal mine to feed the factory, from the local, from the [???] section as they called it, from the coal mine.

Keith:

Did you enjoy that period?

Orowan:

I would say it was extremely interesting. It was really about the most complex equipment in these fields. It was done by Linde, and the place was very charming. Altogether I visited Budapest at the end of July and the beginning of August, and there, I was offered a little paperweight that belonged to [???]. It was a souvenir. These were segments of the turbine blades from the power plant of the mine. The mine was threatened with drowning during spring floods for several years, but nobody could track down the source of the biggest, largest turbine. There was a plate on it, but we knew that the plant, the firm on the plate couldn’t have made it. So one day I walked to Budapest, opposite the university, along the street, with the antiquarian, and in one of the shopping doors, I saw an ancient paperback on turbines. So I went there and bought it for something like ten cents, and the turbine treated there was in fact that old turbine at our power plant. So it took only a few days to trace its origins, and of the firm that inherited that old factory. It was in Munich, and it was the main manufacturer later for Hitler. So the turbine department was practically unemployed by this reason. I went and they supplied the [???] blades including this for the big turbine, and they did it so fast that the turbine could start up, and would give the full power, which was about five times the power it gave before that, two or three days before the spring floods. They were so bad that year that the whole mine, with about a thousand workers, would have been drowned, without this turbine.

Keith:

If you enjoyed this period in industry so much, how come you never went back into industry later?

Orowan:

Oh, that was very simple. In 1937, it was clear that the war was coming, and so when I think Peierls invited me to Birmingham, there was absolutely no doubt in my mind, although the salary I got in Birmingham, I think it was 200 pounds, and one couldn't really live on that, but if a firm in Budapest gave me an additional 200 pounds, for which all I had to do was not to invent anything connected with the liquefaction and separation of gases, so, that gave me a living.

Keith:

Where had Peierls come across your name before?

Orowan:

We met in Germany, in Berlin.

Keith:

When?

Orowan:

This had to be in '30, '31.

Keith:

Yes. So he'd remembered you from then, or did you stay in contact?

Orowan:

No. He knew my publications, I think. Peierls of course is an extreme case of a man who is X to the 9th power times more gifted than one could conclude from his publications. They are very impressive, but very few.

Keith:

Yes. I mean, he's helped so many other people, I mean the number of people you meet who will point to Peierls.

Orowan:

After the death of Wolfgang Pauli, Peierls was the man to whom everybody went for advice.

Keith:

Yes. And it seemed as if Peierls was the man who was always willing to talk to people, as though he always enjoyed talking about different problems.

Orowan:

That might have played a role in the rarity of his original publications, which was really quite an unusual thing. He is really quite an outstanding mind.

Keith:

Yes, particularly in the mathematical sense.

Orowan:

Not only that.

Keith:

Yes. Did you think of going anywhere else in that period? One or two people went for instance to the Soviet Union for a year or two during the thirties.

Orowan:

Oh, you mean when I was in Budapest? Well Ioffe invited me to Leningrad, and I said I should be glad to, but that was the beginning of the Stalin terror, and he could not get the permission to stay. Then he suggested that I should go to Sverdlovsk, but again nothing could be done. Well, I didn’t mind it, because a very good friend of mine went to Akov for a time, and we agreed that he would write me, how things were. If he wrote me that they were very good, then they were very bad. So soon I got a postcard how he enjoyed it, and everything was very good there.

Keith:

So you came to England. When, at that time, Nark Holifan would have been head of physics?

Orowan:

Yes.

Keith:

Did you have any particular ideas about what you wanted to work on in Birmingham?

Orowan:

Well, I did not. I was there only two years, and I don't think I could do much in the way of building up equipment, so what I did there was, to publish a paper on the theory of fatigue, which appeared in the —

Keith:

Was there any particular stimulus for that paper? Any particular problem posed that you took on?

Orowan:

Well, how fatigue came about. And I think that it is still largely so, although details were at that time unknown. That was a time when nobody really believed that there would be a war. It’s amazing. And of course, not only Chamberlain and his colleagues. I think I could best describe it by saying that Chamberlain in a very important sense of the word was illiterate — not stupid, he was illiterate in that he could not read German, and therefore he could not read German newspapers. Just as his colleagues in the government, and most other people, could not. And so the only person that I know of in England who was really well informed was Churchill, because his friend was Lindemann, that is Cherwell, and since Simon worked in Oxford in Lindemann’s department, Simon was the most authoritative source.

Keith:

Yes, and Simon was very important was he not behind the refugee influx into Britain, the organization.

Orowan:

Yes, but only Simon was of importance, because he was the only person connected with it in close contact with Cherwell.

Keith:

Did you make any other contacts in Birmingham, people that you talked about problems with, aside from Peierls? Did you have any contacts with the metallurgy department?

Orowan:

Yes, personally, but not much professionally.

Keith:

Yes. Was Cottrell there at that time also?

Orowan:

No. He came later. When he was there, and then he visited me, I think once or twice in Cambridge.

Keith:

Did you keep in touch with what was happening as regards developments in the theory of dislocations then? I'm particularly thinking of the pre-war work of the two Bergers brothers.

Orowan:

Well, I knew that pretty well, but that was an old story.

Keith:

And there was this question you took up while you were in Birmingham about what became known as the "Peierls-Navarro" force in the postwar period. That was one of your interests before the war?

Orowan:

Yes.

Keith:

How did that particular question come into your head?

Orowan:

Really, it was very obvious that the stress required for new dislocations would not be [???]?

Keith:

As Taylor originally said.

Orowan:

Yes. And so the question was how to photograph(?). And so I suggested [???] function, and well, the rest is history. (his voice fades out here)

Keith:

It's been written.

Orowan:

By Peierls. You've got that.

Keith:

I have that.

Orowan:

There was that big volume.

Keith:

I have the account, you mentioned, in your centennial paper, that Peierls delivered a paper on the crystal complex, ‘39. Do you remember much else about that particular crystal conference? Did you meet Mott there? And Navarro?

Orowan:

Yes, but not for the first time, I think.

Keith:

Did you discuss, had you discussed informally the dislocations with him before?

Orowan:

No. You see, they came to this field when my interest was diminishing.

Keith:

Yes. What were the circumstances then which led to your move to Cambridge?

Orowan:

Well, it was simply that Rutherford died, and Berg came, and Berg wanted somebody in solid state, and I was in Birmingham and he invited me.

Keith:

Were you then invited to build up a group at Cambridge?

Orowan:

Yes. Actually, I left Cambridge because that group became too big. And I couldn't get an assistant. At the end, it consisted of 11 researchers, a secretary and a mechanic, and so I just couldn't, at the end I just couldn't do anything. It was overwhelming, being with them, and administration. And I had to decide where to go. The possibilities were Canberra and MIT, or Princeton, I think, and Oliphant invited me very kindly to Canberra, but I was not sure how long it would take there to build up the university. So finally, I had to give a paper in '49 at a meeting of the AIME in San Francisco, and on the way back I gave a number of lectures here at MIT, and then soon after that, I was invited to MIT. I suggested that first we should do it as a visiting professorship, and this is what we did, between February and June, '50.

Keith:

Then you started at Cambridge; it must have been about the time when the war broke up.

Orowan:

Yes.

Keith:

Has your work at Cambridge directed very much towards war work at that time.

Orowan:

Well, the very first impression I had was in Birmingham. My laboratory was the Oliphant’s laboratory, because he was full of administration and he couldn’t do work so the entrance was the room of his secretary, to the left was his office, and to the right was my laboratory. One morning, I entered the room of his secretary. There was a large empty table, and on the table there was a paper bag about this big, and very dirty. So I asked the Secretary Miss Hice, “What is this dirty bag?” and she said “It’s uranium oxide. Haven’t you read that in NATURE?” So that was the beginning. It was about four pounds or three pounds of uranium which Oliphant immediately bought. And my neighbor in Birmingham, in the basement, was Randall and Boot. At that time, the whole department spent weekends, I think in Bournemouth, working on radar, and it was then that Randall and Boot discovered the cavity magnetron. You remember the story of that? It was published one or two years earlier by a Russian.

Keith:

Was it? No, I didn't know that story.

Orowan:

Oh yes. Not in the original primitive form, but in the advanced form, with the [???] trapping, but he couldn't produce resonance. And so he published it. But nobody read it. So it didn't matter.

Keith:

Was the Soviet literature very isolated at that time? I mean, was there lots of work that was performed in the Soviet Union which simply didn't get diffused into scientific circles in the West?

Orowan:

Frankly, I don't know how much work there was in the Soviet Union. From what I have seen in the meantime — for instance, this summer — they have very desperate difficulty in that they cannot find and choose good people, because the decisive point there is ideological. Now that I was in Hungary this summer, my impression was that it was really not a question of Socialism or Communism. Very often very good people could not get admission to a university because their parents were engineers or doctors or merchants. On the other hand, the sons of workers and peasants enjoyed great preference. And therefore, what one sees really explains what one hears about the economy there. I stayed a week in a hotel, quite modern, beautifully done, but in the bathroom there was no mat in the tub, and the hand with the soap bowl was at the head. These things really occur almost every day. On the very last day, I wanted to cash a traveler’s check in a large bank branch where there were about two dozen persons working. There were two long queues, and two persons were dealing with those, the exchange of traveler’s checks, but there was not one person to whom the idea came that those two dozen who were doing very secondary things, that one or two of them could help. So it really has nothing to do, I think it has very little to do with Socialism or Communism. It really is a bureaucracy of the kind that was initiated in the 18th century and then particularly by Adam Smith, started with the remark that there is probably no talent born with anybody, talent is acquired.

Keith:

Going back to the work you started doing. You mentioned the war work that started at Birmingham. Were you involved in that work when you went to Cambridge? Did that continue the work on the Tuballoys Committee?

Orowan:

No. No. Only so far as I had several empty rooms, which they then occupied, and they were my neighbors. And of course I derived a lot of good things from them. Initially they really were a very exclusive group and no Briton was permitted to join them. So only when, after December, ’41, Kowarski and Halban demonstrated the possibility of a chain reaction, then the work became sufficiently respected so that they permitted the first British young man to join the Tuballoy when they regarded as a great triumph.

Keith:

So what work were you involved in during the war years?

Orowan:

My work on strength, and mainly the work on metal fracture.

Keith:

This was particularly in the context of sheet steel?

Orowan:

Sheet steel.

Keith:

And that was in relation to the practical issues in ships, or very general?

Orowan:

That was quite general. And, as I said, it finally turned out that it was all in the wrong direction. But the practical problem was solved, I think it was solved mainly, by people at Corvel’s(?) who noticed that the brittleness could be remedied by adding more manganese. And then, they eliminated the crude defects of design in the ships.

Keith:

I remember from looking at some government reports during the war, there was a lot of criticism about the quality of the engineering particularly as regards to tanks, the quality of the steels that we used during the war.

Orowan:

What tanks?

Keith:

The British tanks.

Orowan:

Oh, I see. Yes.

Keith:

You weren’t involved at all with that particular issue?

Orowan:

Well, immediately after Dunkirk, because it was said that we cannot produce fast enough armor, so I applied for a patent for a type of armor that would be more effective and did not need steel or only very little. It turned out that a professor in Oxford did the same thing at the same time, but the Minister of Supply — I think Bragg for a while did it. It was the kind of armor they are using now in the most recent tanks. You know, it is — the armor, the steel armor is penetrated because of plastic deformation at a very high pressure. And if you use a ceramic insert, like carborundum, that is what I had in mind, then you can achieve much greater resistance with this non-metallic brittle type of armor, which is set in a matric of whatever kind of steel you like. So then after a while they said that we didn't need it now, and in due course we can produce the steel armor. That is what usually happens. What I found funnier was, in 1938, when I suggested what is called today the smart bomb, which is a bomb with a TV head, a wire guided one. And so I applied for a patent and sent it to the Ministry of Supply, and told them that for three weeks I shall be in Honfleur in France and that will be my address, and they replied that, I think they thought it was not practicable, that it was not needed, and they sent it with letterhead on the envelope of the Ministry of Supply to the Hotel Charblon(?) where I was staying. It arrived about 10 or 12 days later. It was nicely opened so evidently it went to Paris in the meantime and now the Germans did use the wire guided — during the war. So I don’t know, was than an initiative of von Braun, or did it go through channels of Minister of Supply and so on?

Keith:

The expansion in your electrophysics group, was that mainly a postwar thing? Did they expand very quickly after the war?

Orowan:

I think mostly after the war.

Keith:

How did you see your group going when the war ended then? What kind of problems did you want to attack?

Orowan:

Well, the [???] there were Kahn, Honeycomb, all on recrystallization of aluminum, and then one doctor’s thesis was on the plasticity of ice, because at that time, there was a glacier physics group, and so we went in fact once to Switzerland just to look at glaciers inside. So we really didn’t go in a certain direction, but in several directions that seemed of interest.

Keith:

Yes. Do you think Kahn's work was the most outstanding of the students you had in that period?

Orowan:

I think his and Honeycomb's. They did, they worked on exactly the same problems, and in fact they competed very sharply with one another.

Keith:

Were their approaches different? I know Kahn's work but I don't know really what Honeycomb did.

Orowan:

More or less the same.

Keith:

So they were both making crystals, staining them, and then X-ray crystallography.

Orowan:

Yes.

Keith:

Can you tell me how you came to be interested in that particular problem of recrystallization?

Orowan:

Yes, I can. I had an acquaintance, with an Austrian refugee, who was working somewhere in the west of London. He died during the war. He gave me several reprints, and in one of these reprints I found X-ray reflection spots split up in a very curious way.

Keith:

Yes. These were the asterisms?

Orowan:

Well, not quite, but they were what I called then polygonization that is, bent crystals, which after heating splits up into a polygon-like arrangement, which then gives, instead of the asterism, a row of points. That was the beginning of it.

Keith:

So you actually named it polygonization yourself? The word comes from you?

Orowan:

Yes. That was the beginning of the work of Honeycomb and Kahn.

Keith:

You must have been very pleased when they actually produced eventual proof of it.

Orowan:

Yes. It was nice, very interesting.

Keith:

I find it intriguing the way that Kahn's explanation, in terms of dislocations, actually came from Cottrell. I mean, did you not think of applying dislocations, to this particular problem?

Orowan:

Not really, because it was simple without dislocations.

Keith:

You think Kahn didn't need to apply dislocations to it.

Orowan:

Of course it can be done by putting the problem in terms of dislocations. But it seemed to me, much simpler.

Keith:

Yes. You'd thought of it yourself. You'd thought of doing it that way yourself, had you, and dismissed it? Of using dislocations to explain it?

Orowan:

No. I think I didn't think that it was necessary or urgent, or very essential.

Keith:

Did you stay much in contact with what was happening, the expansion of dislocation work in the postwar period?

Orowan:

No, because after I arrived here, first of all, the center was [???], the contractor(?). Then came the main point of continental drift, and parallel with that went this problem of the theory of history, and economics. That it existed or it didn’t.

Keith:

Yes. How did you become interested in the continental drift problems?

Orowan:

Oh, that is a difficult question. How? That was very long. Oh yes, now I know. Have you heard the name Beno Guttenberg?

Keith:

No.

Orowan:

He was, I think, the best geophysicist of the decade. He retired ten or fifteen years ago. He was professor of geophysics in Pasadena. They had a conference on rock mechanics, rock strength and so on, and he invited me to give a lecture. After that he invited me for a visiting professorship to give a series of lectures on the mechanics of geology at Cal Tech.

Keith:

What dates are we talking about?

Orowan:

‘56 was the lecture I gave, and '58, in fact, was the time that I spent in Pasadena, and then two or three months at La Jolla, at the Scripps Institute. And then, again, that was pushed into the background, particularly because it looked so difficult to find somebody who could appreciate the points of view. May I see if I have something that I could show you. This is the preprint of what I tried to find. I have reprints of it; I don’t know where they are.

Keith:

What were your main contributions in this field since you started on your interest in the mid-fifties?

Orowan:

They are quite a few there. It would take time to collect them. But the main point is that, you know the system of the entire middle Atlantic ridge disc (much noise on tape, did he say mid-ocean rift?) The most significant object on the earth, because, see, this is the mid-Atlantic Ridge — it goes this way, to stay always exactly in the middle between the opposite continents. If there is a jump, then the ridge jumps into the central position, and this is seems cannot be explained at all on the ground of mantle convection. It requires more subtle explanation. Frankly, I can’t, I have no reprint of this, and I sent it to the Royal Society a few years ago, and the man who reviewed it somehow, I think, did not quite get what was involved, and it is still there. I have two such papers which are still in the Royal Society office. The first one is in the [???] and that refers to the theory that the [???] would be due to dislocation locking. I somehow got, from a letter I received from Cottrell, I had the impression that it would have to be tested very sensitively, so I postponed the publication many years ago. The fact is that it cannot be due to locking. The necessary experiments are, well, they were all not published, but are in that manuscript. They are representative of a group of experimental effects — they are really the most spectacular I know in this field. So this is what interested me very much, together in with that thing which I am doing now.

Keith:

Did you do this work very much on your own of did you have students?

Orowan:

No. I did not. I don’t think a student would have done that.

Keith:

No, it's almost a personal project.

Orowan:

Well, this couldn't have taken… (terrific noise on tape blots out voice) …besides, usually if you give something to a student, it is for calculating. And here, we are of course extremely far from any solid background for calculation.

Keith:

Yes. It occurred to me, from a slightly earlier period. I wanted to talk to you about — was there not a series of seminars held during the war of people interested in dislocations, brought together, people from Cambridge and Bristol?

Orowan:

Yes, there was. Cambridge, Bristol and Birmingham. And we met a number of times, in these places.

Keith:

On whose initiative were they set up, do you know?

Orowan:

I don't remember.

Keith:

How many of them did you actually attend yourself?

Orowan:

I attended all of them.

Keith:

How many would there have been altogether?

Orowan:

Colloquia — not many.

Keith:

How big would they be? How many people attended them?

Orowan:

20 or 25 or 30.

Keith:

Yes. I mean, I assume there would have been Mott and Burrow and Bristol.

Orowan:

Yes, that's right.

Keith:

And who else would have been at Bristol at that time?

Orowan:

I'm not sure about that.

Keith:

I don't think Frank went to Bristol till 1945. And Cambridge, presumably Bragg would have come, would he, Bragg?

Orowan:

Yes. Now, there is one reason why I know that he did not attend every lecture, because there was a colloquium in Cambridge, and at that colloquium, I gave a short talk about the possibility of dislocation locking by [???] atoms, as a cause of the phenomenon, and added to it, why it is unlikely to work. And while I was giving that, Bragg was in his office and Cottrell was with him. Cottrell did not listen to that and Bragg did not.

Keith:

So why was Cottrell not sympathetic to this? I mean, did it go directly against his own theoretical viewpoint?

Orowan:

At that time he did not have that viewpoint yet. And he didn't get it from me, because he was at that time when I gave the lecture, he was with Bragg.

Keith:

Can you remember other people who attended that particular seminar series apart from the people we've mentioned?

Orowan:

I could remember Nye from Cambridge. I think he was probably my third doctoral student. The first was Bascoll. He's in engineering in Cambridge. And then there was the one who was only nominally my student, because he was quite independent and much beyond that. He was Hill. Rodney Hill. I think I had not arranged for Hill to come to Cambridge.

Keith:

So you supervised John Nye, did you, on the triple? The project?

Orowan:

Oh, the project itself was started by Bragg. Bragg had had the idea, after we experimented with floating balls and so on, then Bragg had the idea of using soap bubbles.

Keith:

What kind of balls did you experiment with?

Orowan:

I don’t know, with celluloid or what. But of course they all had friction and therefore didn't work. And then one day he had the idea of soap bubbles, and when I appeared in the lab in the morning, our mechanic already was making the equipment. The only difficulty was that he couldn’t produce soap bubbles of the same size.

Keith:

Yes.

Orowan:

But then I made, instead of this kind of nozzle — I bent it like that, and it produced soap bubbles of the same size, but this was Bragg's idea. Nye was then my doctoral student, and his doctor's thesis consisted of two parts. The first, what he did with me on rock salt and the second was Bragg's problem.

Keith:

Yes. Did you have much contact with people on the X-ray crystallography side, which would have been Taylor's group?

Orowan:

Well, I did when I came there. Those were Bradley and Lixon. I don't know, have you heard about Bradley?

Keith:

Yes, I heard he left very suddenly.

Orowan:

Yes, but where is he now? He went to Jessup's in Sheffield.

Keith:

Well, he became ill, and I'm not sure, I thought he was dead. I could be wrong.

Orowan:

You can switch it off for a moment.