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In footnotes or endnotes please cite AIP interviews like this:
Interview of Wendell Furry by Charles Weiner on 1971 August 9,
Niels Bohr Library & Archives, American Institute of Physics,
College Park, MD USA,
For multiple citations, "AIP" is the preferred abbreviation for the location.
Some of the topics discussed include: his youth and education; working on his Ph.D. at University of Illinois; summer symposia at University of Michigan; his work in the early stages of his career; collaborating on a paper with Oppenheimer; accepting position at Harvard in 1934.. Others prominently mentioned: Wolfgang Pauli, Arnold Sommerfeld, Ivar Waller, Hendrik Kramers, Werner Heisenberg; George Uhlenbeck, Frank Carlson, Walter Heitler, Victor Weisskipf, and Niels Bohr.
This is Charles Weiner, asking some questions and commenting, in a discussion with Professor Wendell H. Furry, in Copenhagen — I think that’s important to clarify — at the Bohr Institute in Copenhagen. The first thing I want to do is backtrack. I know that you were born in a farming area in Indiana. You went to school in Illinois.
Yes. Well, I went to school in Indiana until I was ready for graduate school, and the University of Illinois had at that time probably a better reputation than the University of Indiana, although perhaps this should never be quoted, in physics, and also my Professor at De Pauw was a PhD from Illinois. So he was sending his various students off to the state universities in the general region, and he had me apply to two or three of them for a teaching assistantship which was to be my means of existence, and Illinois gave me one. So I went.
Who was the professor?
Professor O.H. Smith, who won the Orsted Medal in 1950, I believe. He was the source of a good many graduate students. When he left one institution and went to another, the number of physics graduate students coming from the institution he’d left dropped way off, and the number coming from the one he went to usually went up. He got to De Pauw. I’m not sure whether the group I went through with was the first one that had their complete, all their work with him, or whether it was the second, at De Pauw. So I got to Illinois.
May I backtrack, before you got that far. As an undergraduate, you worked in physics, but how early on had you decided that physics would be your interest?
Well, there was a lot of propaganda about chemistry when I was a boy, and I ran across some of it when I was in high school, decided I’d be a chemist. And I was rescued from this fate by a series of accidents. I found that I was expected to –- I found they had some requirements for chemistry courses mentioned –- oh yes, high school chemistry, of course, was stated in the catalog at De Pauw. It was required for the main chemistry course, the one that was obviously desirable. You could make only some sort of minor baby course if you hadn’t had high school chemistry. I found afterwards that this was one of those things which catalogs contain which the department is only too eager, in the face of a promising student, to violate. But I didn’t know it at the time, so I shied off, contented myself with taking mathematics and German the first year as my two main studies, and during my freshman year I heard some of the boys talking and one of them expressed his opinion very emphatically that physics was the thing to major it, and so I thought, “Well, I’ll string along and take a year of physics, see how I like it.” So I think the year I signed up for physics was quite probably O. M. Smith’s first year there. He was a very charming man, and I’ve been in physics ever since. I eventually took in college the home economics course in chemistry, which is available two hours a week, which taught me a few things, and gave me all the chemistry experience I ever want to have.
Had you had any science experience at all in high school?
High school physics. It was quite widely taught in Indiana at the time. It was usually the only major science taught. Many of the small high schools did not have chemistry, so physics and physical geography, which obviously was just out of a book and nowhere near a serious course, were my high school science courses.
You entered college then in 1924.
Yes, in 1924, to ‘28.
When did it become clear to you that you wanted to go on to serious graduate school work in physics?
Well, I made myself a mathematics major, when I was asked to name a major at the end of my freshman year, some time like that, just to mark time. I changed to physics major some time like the beginning of my junior year, and either the end of that year or the beginning of the senior year, I’ve forgotten which, I told Professor Smith that I was very interested in going on and hoped he could get me a way to do it.
What about your family? Was there anything in the family background that contributed to this interest? For example, I don’t know the occupation of your parents.
Well, my father was a minister –- he retired a little bit before I started high school, on account of ill health, retired into even more drastic poverty than was the lot of country Methodist ministers who were active. There was nothing particularly scientific in my family background, except one brother did go to an engineering school and became a rather successful engineer. He went to Roosevelt Technic in Terre Haute, which is a minor school, of which not too many have heard. It’s still there. He was my older brother, 14 years older than I, and while he never became a high class engineer of the kind which Harvard talks about as lowering the degree of empiricism and that sort of thing, he was successful at working for various industrial companies around the region. My father managed to accumulate as modest number of books, which was fortunate because our high school library didn’t amount to much and there was no public library in the town. So I read this and that, including the encyclopedia, an old minor encyclopedia which I never saw another copy of, except the one my father owned. This and that, I picked up some knowledge of mathematics.
I also read my older siblings’ high school books and a little bit my brother’s college books voraciously. The solidest thing you got on science in any event was of course the physics textbook by Milliken and Gale, and so -– I had that background. But a man by the name of Edward E. Slosson wrote books on creative chemistry and that sort of thing which were sent around as propaganda by some company interested in chemistry. I don’t know whether it was the Chemical Rubber Co. which later published the handbooks or whether it was something else. Sets of those books, sets of books glorifying chemistry were sent out to various high schools at that time, and so I devoured the ones that were sent to Farmersberg High School, and this was part of the –- But this was all leaning towards chemistry, which is what had the glamour at the time. It was only in college that I got into physics.
You emerged from De Pauw as a physics major. Were there many others with the same interests?
There were about six in the graduating class –- well, probably about seven. Two of them were girls who did not go to graduate school. I think practically all the rest went to graduate school somewhere or other. Probably the best, the one who became best known of my classmates was Charles Whitmer, who afterwards occupied, and I guess still does occupy, a fairly advanced position in the NSF. Whitmer went to Iowa. I went to Illinois. Someone else went to Minnesota. Minnesota, incidentally, was regarded as one of the most desirable schools of all, that and Wisconsin, in those days.
That was because of Tate at Minnesota at the time?
Wisconsin had Metenhall, Bright —
I don’t think they got Bright till a little bit later.
Bright in ‘33 or so, yes. Well, how did Professor Smith arrange that you could apply and get support for graduate work at Illinois?
I suppose he did it the way any professor did. He probably told them that he had certain students that would be interested in applying, and I think, you know, he sort of rationed the applications, to give them a chance. Michigan had an excellent recommendation –- had an excellent reputation at that time too, and so I applied to Illinois and Michigan and I don’t know whether there was a third one or not. I don’t remember whether Professor Smith told me to write to them and ask for the application blanks. He probably did. He also of course got in touch with them, recommendations, that sort of thing. Michigan, I remember, answered very promptly -– the same thing Harvard would have answered, I suppose, the same thing that Harvard would have answered until a very few years ago, namely, that they didn’t make a practice of giving such assistantships to their first year students. Well, that ruled me out, since I couldn’t afford to go without one, so I was very happy when Illinois offered me one.
The source of funds at Illinois was the regular department budget?
The regular budget, I suppose. These were half time jobs, paid just slightly less than half the rate the full time people got. They were rather trivial in size, in fact. My salary was $700. The full time man got $1600. Of course, those were 1928 dollars. If they’d been 1971 dollars it would have been impossible. That included all tuition and fees, everything like that, plus of course office space in the lab and that sort of thing.
What were your responsibilities at Illinois?
To teach a couple of lab sections and a conference section or two –- the engineering physics course, like most institutions of size, and in fact a good many that weren’t of great size, they had one for the engineering and science students and then another course for non-scientific people. I got assigned to the one for scientific people. And of course, in the course of doing that for a couple of years, I obviously had a few students who have since become famous. They took physics under me although I was just a sprout at the time myself. One man that I encountered later, I said, “Oh, you had physics with me,” and he said, “Yeah, what about that B?” Obviously he’d expected to get straight A.
Who was that?
That was a man named Newson, who became pretty well known in the chemistry department at Chicago, and –- Julian Knipp, long time chairman at Tufts, also. He was the son of a professor at Illinois. He was in my section in elementary physics. And every now and then I encounter another one.
What courses did you take as a graduate student?
Well, this was affected my first year partly by the lack of confidence that Illinois showed in the preparation of its graduate students, which may in some cases have been justified, and partly by the simple fact that the older graduate students, most of them were teaching assistants -– teaching fellow is a Harvardism which was not used. Most of the graduate students were teaching assistants, and the older ones had first choice, of course, on the hours. They could tailor their hours to take the courses they hadn’t picked up yet that they wanted to take. The courses were run in a very simple way. Of course at that time, although Illinois had a student body of 10,000, the physics department had only five or six professors of any real standing in it, who taught courses for graduate students, and at the time I entered, it was the last year of Professor Carman’s headship of the department. Wheeler Loomis came to be head at the beginning of my second year in 1929. At the time I first went there, the only courses practically in theoretical physics being taught were taught by Jacob Kuntz. A man who had come from Switzerland not long after I was born and had had a slightly checkered career in the United States, during a year or so I believe he worked as a Pinkerton detective, but he’d been a physicist in Switzerland. He got himself a job and had been at Illinois quite a few years. Well, he gave each year -– incidentally, Kuntz was a character, and he did not like quantum mechanics.
He had some of Einstein’s prejudices against it, developed very strongly at that time, developed on his own. He had in fact written his major work in 1907, the year I was born, and published it in Switzerland or Germany somewhere, on “Physics on a Mechanical Foundation,” basing everything on Lagrangian and so on. Well, they do it now, except they’re quantis. Everything was based on some kind of a mechanical picture of the world. So he was very much out of sympathy with the developments in quantum theory, which of course were a lot newer then than they are now. Well, the only real solid theoretical physics was one five hour a week course given every year by him, and this would be one of four different subjects, you see, spaced along. He had one on dynamics and one on electrodynamics, and one on –- let’s see now, thermodynamics, which I never did have, and one on –- was it hydrodynamics or something else? Anyway, the thermodynamics course of Kuntz was the plum to take, my first year, but naturally all the older teaching fellows who hadn’t had it yet wanted to take it. So I took sections at that hour.
I probably might have been regarded as not prepared for it yet, anyway. But the work I took in my first year was to some extent listening to talk about, lectures about the electrical discharges through gases and the beginning developments in atomic and molecular physics, given a little bit more seriously and from the point of view of people who had actually done more of it than I’d had. Also I took a mathematics course on differential equations which repeated a good deal of what I already knew, although there was some new in it. So it wasn’t really until my second year that I got into the solid courses. Then I got into Kuntz’s electrodynamics, and I also got into a course of complex variables, which was a five hour mathematics course, very solid, but would be regarded very childish now. Let’s see -– there was some idea of breaking people into laboratory work fairly early. Oh yes, I remember now, I did an experimental Master’s thesis. I was pretty well engaged in that by my second year, and it was a flop, actually, but they gave me the degree anyway.
Yes. This involved blowing glass and making a vacuum system. Almost everybody’s research involved that in those days. Well, I had some of the most amazing experiences with my glass blowing and my vacuum system, but I don’t guess this is the time to tell those in detail. On one occasion, I managed an explosion which threw all the mercury out of my McCloud gauge to all the corners of the room, demolished practically every bit of glassware I’d so painfully constructed.
Were you working as sort of an apprentice on these things, or were you supposed to teach yourself the techniques?
Well, I think they had informal sections now and then in Professor Lipp’s office, in which he would teach us to do some of the glass blowing tricks. After we learned a little bit, we were supposed to perfect the thing by hard application ourselves. There was one part of my apparatus which was supposed to be too difficult for me to make. That was sealing a filament into a tube. And for that, I had to get the – had to get it done by a glass blower in the chemistry department. The physics department didn’t have any glass blowers. This man was very temperamental and probably also very busy. It was impossible to get him to do things for long periods. After my apparatus had gotten broken a time or two, or something had failed about his work and it had leaked or something, and he was asked for the second or third time to make this filament seal for me, he put it off so long that I was in despair.
But one day, in switching off and on the light in one of the rooms in the laboratory, I suddenly thought to myself –- what in the hell, this guy, he stalls along and won’t make this seal for me, and it exists in millions in these bulbs. And then a great light dawned on me. I got a bulb, broke off the neck of it, attached my kind of filament to the filament leads, and succeeded in sealing the neck of that bulb onto my tube. Thus I made my own filament seal by using one of the mass produced ones. That was my one stroke of intelligence, I suppose you could say, in any of the experimental work that I did for that thesis. The rest of it was pretty God damned silly.
Was it primarily designed to familiarize you with instruments and with building your own apparatus? Or was it a specific experiment?
That was the general idea. If you were going to do an experimental PhD thesis, you of course would need a great many of those skills. Obviously, there was one glass blower in the university who was in another department, so it was really up to the individual to do most of his own, in those days.
Had you thought of doing an experimental PhD thesis?
I didn’t know what I was going to do, but by the time I got through with that Master’s degree, I was very sure that I was going to do a theoretical PhD.
There had been theoretical PhDs at the university?
Yes, Kuntz had given them. Actually my degree though was under Bartlett, whom Loomis brought there, and I’m not sure but I think Loomis didn’t bring Bartlett until 1930. And Bartlett started teaching quantum mechanics, and he wasn’t a good teacher at that time. He must have improved a great deal. I had some of the worst instruction I believe exists at that time. The man under whom I had my complex variable course I believe could be called the world’s worst teacher, bar none, and I early devises that epithet for him. Very few of the class learned anything. Only the most serious and determined people learned it on their own by reading books and so on. What he said was an obstacle to us rather than any help. Of course, at this time it was possible to be a second year graduate student without having heard anything at all about rigor in mathematics. This man tried to teach it, but in such a way that none of it penetrated at all. I got through the course having learned a good many of the practical things about how to use complex variables — mostly on my own, as I say a still with no impression whatever of mathematical rigor, except that it was something that a very bad teacher tried to teach.
This man had failed so completely to teach anybody anything, by the end of the first term, that he tried to cover up the fact that he had not been able to teach anything to the bulk of the class by simply giving the whole class A’s for the term. Unanimous A’s. I don’t remember whether he did that for the second term too or not, but probably. Bartlett wasn’t a very good teacher in those days either, and of course quantum mechanics was a difficult subject which is not thoroughly understood by very many people at the time. I can remember often –- won’t say whenever, but frequently, when a member of the class would get him to try to explain why something was done the way he was doing it, he would reply, “Well, this is what one does.” So I did my thesis work with Bartlett. It involved large amounts of straight numerical calculation, on Heitler-London calculations of molecular energy levels. I made my claims to the Marchand calculating machine, which for many years was my love. I still like it much better than any of the other desk calculators. It’s more rational.
What was Bartlett’s interest at the time? His own research?
Largely these molecular energies. I didn’t become acquainted with anything else he was doing. He was writing papers on the subject. What happened was this. I served for two years as a teaching fellow. Maybe you want to cut off the graduate work?
No, it’s very rich, part of the background.
I was a teaching fellow in this course that I’ve described for the first two years, but –- and Bartlett was being brought in, my third year, and in the meantime Loomis, who had his ear to the ground, heard from one of the people up in the spectroscopy lab that I had been observed coming up there, although I knew nothing about spectroscopy, and sitting at a desk and working with a little Marchand that they had. This was one of the really early Marchands. It was not driven electrically. You reached behind and twisted a little handle, counter clockwise, for some reason, in order to drive the thing forward. You twisted it the opposite direction if you wanted to subtract or divide. And it was all hand powered. I’d been observed coming up there and figuring with that thing. Well, I was fascinated with the gadget, and I had long been interested in trying to compute things. Back when I was in high school I calculated pi to 17 places or so and wished I could get it to more. I was fiddling with this thing, presumable trying to calculate pi to another place or two.
Someone told him I seemed to be interested in that, and Loomis got his eye on me as someone who might help Bartlett, because Bartlett was interested very much in doing these numerical calculations connected with his work on valence structure and so on. So I was introduced to Bartlett the beginning of my third year, and I think that was his first year there, to be his assistant, a research assistant instead of teaching assistant, and to help him with his calculations. So he had the practice of laying out his calculations with a minimum use of paper, columns of tiny figures, and carrying out a computation, recording all the main steps that had been done on the Marchand. The Marchand did have a modest possibility of accumulating something, but it had nothing that’s nowadays called storage, so you had to write that down, a great many steps. I followed his style. I wrote tiny writing with little columns of figures, crowded on sheets of paper, hundreds, probably thousands to each sheet. And thus I earned my keep the third year instead of being a teaching assistant. Naturally, I got started doing some of these calculations on my own for a thesis, and so I continued that to my fourth year. My fourth year, I was given the fellowship of the department.
This paid only $500 but it didn’t require any work, except on your own thesis. The department of physics at Illinois at that time had three such free scholarships or fellowships –- one for a first year man of $300, one for a second year man of $400, and one for a terminal man of $500. Those were the –- of course they all carried free tuition and fees besides. That was the extent of fellowship aid available in the United States’s fifth largest university at the time in physics. So I had the $500 fellowship my last year, during which year I was able to get married because my wife somehow or other got a sympathetic female member of the school board to appreciate that she wanted very much to get married and that somebody else wanted her even more to get married, and that it would be impossible unless she would be allowed to be made an exception to the rule that no one could teach who was married. In those days no female could teach who was married. So she managed to break through this barrier at that time, which was remarkable, and we got married in the middle of my last year.
It was a sort of Depression-induced -–
That was 1931-32.
— the regulation on teaching?
The regulation I think had probably existed before, but it was backed up more heavily with the Depression mentality, that after all a married woman out to have a husband who could support her and God damn it, the girls need these jobs. But I think it had existed before.
I know other states, Ohio had the same regulation.
Well, anyhow, that was the general background of how I worked at Illinois. I had no notion of which particular part of physics I wanted to do when I went there. I was very interested in the confident way other people talked about exactly what they wanted to do. I hadn’t really known what I wanted to do when I went to college, and had found out while I was there, so I assumed I was going to find out what I would do while I was in graduate school. And after I left graduate school I assumed I was going to find out what I was going to do from there on, because I didn’t really expect to keep on filling those pages with tiny figures.
Well, let me ask a few questions about the required courses for the PhD degree. Were there certain required courses? Was there a certain routing on the oral or written examinations which you had?
I don’t remember exactly what you -– I don’t remember whether we had any chart drawn up at that time, such as many departments have, listing what you’d take. You had an advisor, and you pretty well found out that he was in fact your dictator, almost. I mean, you wanted to do what was right, didn’t you? You wanted to go ahead in the department? I think it was more or less that way. I don’t remember who was my advisor at first, but after Loomis came there he was my advisor, and I think that he was probably advisor for nearly all the students in the department.
But not necessarily your thesis advisor, Bartlett was.
No, no, no, I mean the advisor as to what to take in preparing, program advisor. There were just these basic courses it was obvious everyone would need -– Kuntz’s courses, course in quantum mechanics by Bartlett, and a few courses in math, it was evident that everyone would want or need, so you sort of got put into as many of those as there was time for. I never did have Kuntz’s thermodynamics, or whatever else his fourth course was. I had only his electrodynamics and his dynamics, taken in backward order of what you might have expected, dynamics taken second, just the way they happened to come along. The requirements were mainly based -– I mean, the main base was passing the courses you got put into and of course making A’s in a suitable large fraction of them, the only place where the requirements for the degree pinched on a person was that there was an oral preliminary examination, and this was an exam at which two or three members of the department and probably some brought in from say mathematics sat around and asked anything they wanted to.
No prescribed fields?
No, it was just asking you the sorts of things that person who wanted to go ahead and do a PhD thesis in physics presumably ought to know. Naturally, if they stumbled onto something that you simply had never studied -– probably they conferred a little bit beforehand and know what courses you’d had and what it would be reasonable to ask, and if they did ask something that you just never had heard of, you could simply state that. I know a lovely story about when this happened in an exam. McKilbert was present –- not at Illinois -– I won’t tell it now. So I knew amazingly little, but I made a pretty good appearance at my exam, and I had picked up some other things that had been told around, so it was a very satisfactory exam, and I began to be regarded as one of the very satisfactory oncoming boys, and Loomis was eager to push me for a National Research Fellowship.
Before we get on that, one other question about Loomis –- I’ve looked at his department reports of those years. Fortunately they’re preserved in the archives at Illinois. And the thing that impressed me most was the deliberate efforst he made to build up the department. He brought in apparently a lot of outside speakers.
Do you recall any of those? He had a lot of lecturers from the US and abroad.
Yes, I remember going to a good many of those – and understanding practically nothing that was said. They would appear at the physics department colloquium in the late afternoon ordinarily, and I was utterly baffled by a large part of what was said. For one thing, the foreign ones often spoke English very imperfectly, and to my raw Indiana ear it was impossible to sort out their accent and get what they were actually up to. I remember one of them kept referring to the “specificates” all the time, and I heard the whole talk and never dreamt of what the “specificates” were, and it wasn’t until some years later that it dawned on me that what that man had been referring to was the specific heats, as the evidence for various things he was saying. Well, one at least laid eyes on these luminaries and was kept humble by not understanding what they said. Another thing Loomis did, for me in particular, was to get me to the 1931 Michigan symposiums, summer symposium. This was one of the early ones. I don’t think it was the very first one.
1927, it started.
Yes, they’d had them for a while, but in 1931, that is the year before my fourth and final year at Illinois –- I mean, after all, when you work half time for the first three it takes a little longer –- although three years was, as you know, the standard. This business of having everybody take five or six years was not the thing in those days. Anybody who could arrange support somehow so that he could work fulltime, and there were very few such, but if you could, the idea was, you got through in three years, no question about it; if you weren’t a flop and if you didn’t have to do too much outside work to earn your way you got it in three years. And even if you did do half time work, unless you got married too soon and supported a wife, which some of the older men were doing, they would take full time work and have only a little bit of time left to spend on their thesis, and so they’d live on the $1600 for maybe another three or four years. But four years was about average, for a man who started with a half time job, and maybe took one of the small fellowships for one of the years.
Anyway, this was 1931. Loomis arranged that I would go to Michigan, and he though that surely if he wrote a letter to Professor Randall about how I was one of his most promising people coming on for the PhD and so on, that the department at Michigan would waive the requirement that anybody who didn’t already have a PhD had to pay summer school tuition to attend this symposium. Well, this of course was the honorable and proper way to do it. It resulted in my being turned down flat and having to pay the tuition. Other people who didn’t have their degrees yet simply said nothing about it, some of them, and simply walked in and out of the symposium rooms and got the benefits, but I was sent under proper auspices with all the documents, and the documents weren’t accepted. So that ate up $38 of the $100 that Loomis had arranged to support me with for the summer, leaving me, let’s say, $62 for an eight weeks session. Obviously this had to eat up a little bit of whatever few dollars I had left over from previous years of endeavor. After all, I was in training to live on $200 less the following winter so –- I presume I had some savings.
What was the program that summer at Michigan?
The guest speakers were Pauli, Sommerfeld, Kramers, and I’m not sure –- Oppenheimer was there for a certain amount of time. I don’t know whether he was a regular guest lecturer throughout the time or not. Anyway, in order to justify this $100 grant, I was supposed to write out notes on the lectures by Pauli and Sommerfeld, and bring them back and submit them to Loomis. I submitted them to Loomis, and he wrote out a voucher saying that I’d spent 133 1/3 hours working for the department at 75 cents an hour, and got me my $100, but I don’t suppose he ever did anything with the notes except put them away somewhere and leave them until they got thrown out.
Maybe they’re preserved along with the list –-
— I doubt it. I spoke with him about it in later years and he said, “Well, we never did anything with those, they got thrown out,” or something, — I would have liked to have them myself. They’d be very interesting to look at as a specimen of how I took notes on things that I certainly didn’t understand very well. It was the first time I heard about the WKB method, it was the first time I heard about how to calculate distribution functions with the grand canonical ensemble and that sort of thing. I didn’t understand a word, by Sommerfeld –- it didn’t dawn on me at all. It wasn’t until the following year that I took any course in statistical mechanics. Yes, it was my fourth year at Illinois that I took statistical mechanics under H. M. Mott-Smith, not to be confused with Ellen Mott-Smith, quite a bright guy anyway, taught me a number of tricks on the side, which are useless but very interesting.
About the summer school -– a few months or perhaps a month after that, Pauli was at the NAPS meeting I thin in Pasadena, where he made his first mention of the neutrino.
Pauli was already mentioning the neutrino that summer in private, in evening meetings. He did not lecture on it in his regular symposium lectures. Pauli had something on his mind about a neutron of course, he called it a neutron at the time. It was already gossip around the symposium. Heisenberg also visited, for a very few days, in that symposium. And to indicate the sense of status or lack of status that I had, my roommate, who was from some small college –- whether he was going to the symposium or doing something else there, I don’t remember –- anyway he was very interested in physics. Whether he was going to the symposium as I was –- he probably was, at least a part of it. He somehow or other wangled the idea that he and a friend could serve the refreshments, at the evening meeting where they had Heisenberg present, and he took me along so that I could be there as a refreshment server and get to see the great man. Now, you see, I don’t doubt that if I had just sort of snuggled up and kept my ear to the ground and known about these things and so on, I could have simply walked into the meeting as if I had a right to and everything would have been well. But this is a symptom, I guess, of the fact that I really felt like a good deal of an outside.
Was this a separate meeting apart from the regular summer session?
Well, it was an evening meeting to discuss things. They often had these. I attended several of them.
Was it special?
I got the feeling about this Heisenberg one that it was pretty special. Anyhow that’s how I got to it. But I did go to some of the others. On the other hand, Kramers’ lectures, which I thanked my stars I wasn’t expected to report on, I went to those –- I mean, I went to all the lectures I could, showing an appetite which was not really kept up over the years. But Kramers’ lectures had me baffled. This was at the time that he was really getting well developed his particular way of dealing with angular momentum, which is a sort of spinor method but not call spinor method. It’s based on algebra, psi and eta, in which these are really the bases for spinors, except that’s not the way Kramers talked about it. This had me greatly puzzled, and eventually I noticed that he would every now and then say, “But this is something I talked about more fully last week in one of the evening meetings.” Now, Kramers had been having these evening meetings right along for people who were really interested in this stuff and wanted to hear more, but I hadn’t heard about them until I just picked up the fact through going to lectures. At that time I concluded that, well, I’m so far behind now, there’s no use my taking on any more, so I didn’t try to go to them.
Were there many people in your category, predoctoral physics students?
I don’t know what the mix was. I’m sure, I’m morally certain that there were other pre-docs there who had simply mixed in quietly and had not paid any tuition. I’m sure one or two of them told me about it, “Why were you silly enough to take that letter in to Randall? You should have just started coming.” But I don’t remember who they were or anything about it. But it was very interesting.
Were there informal discussions? My impression of it from what Smith has written about it and Randall has written and told us about it was that there were formal lectures but much of the learning took place in the informal tennis games or swimming or parties or discussions at the pool or something.
Well, I was never involved very much in too much of those informal activities. I really felt like a very small potato. I was one of the smallest potatoes in sight. Also, a great many of these things –- well, you know –- they were arranged sort of informally and socially. They’d the people they knew, who were visible. Well, I wasn’t highly visible and wasn’t really trying to be. I received wonderful hospitality a few years later, in 1933-34-35, say, when I went to Michigan -– well, not 1933, but 1934 –- 1935, ‘36, ‘37, I’d better say. That was about the period. Various things kept me away up to about 1935. I received wonderful hospitality then, as a somewhat older and little more known individual.
You had more confidence too by that time.
The big shots of the thing were very friendly to me, very hospitable, and –- well, when they took one of the group pictures, for instance, Goudsmit grabbed me and placed me right between him and Heisenberg in the front row!
That must have been a good feeling.
That first year, I felt very small. But I got some impression of the people’s personalities certainly, and a little bit of a vague glimpse as to what theoretical physicists –- which I inspired to be one — did. I still didn’t quite understand quite what they did, but I had a little bit more inkling of it. One of the things I remember was my first contact with Uhlenbeck’s remarkable way of explaining things. Uhlenbeck was not, I believe, one of the regular lecturers then. But I was terribly puzzled by some of the things Sommerfeld had said, and particularly about the Einstein condensation in Bose gases, and in mentioning this to somebody who was a graduate student at Michigan or knew more about the place, that I had just not understood what Sommerfeld was up to at all, — Sommerfeld I’m sure had not made it plain by anyone’s standards –- except his own –- somebody said, “Well, let’s go and ask Uhlenbeck about it.” So a few of us went to Uhlenbeck’s office, and he started lecturing in his inimitable way, and explained the whole thing to us and a great deal more abut the Einstein Bose statistics, doing some tricks which I remembered from then on about macrostates and so on.
But one of the strange things was that Uhlenbeck told us that there wasn’t any such thing as an Einstein condensation, that Sommerfeld was all confused about that and Einstein had been wrong, — his calculations were wrong. This is as I remember it. Now, if you ask Uhlenbeck, he may deny the whole story, but that’s what I remember, and of course it was Uhlenbeck who was wrong. There was something obscure and perhaps a little bit unrigorous in Einstein’s method of calculating, but Einstein was as usual not wrong of course. There is an Einstein condensation. Uhlenbeck at that time, as I remember it, expressed complete disbelief in the existence of such a thing and told us that Sommerfeld had simply been wrong about it and so had Einstein. Anyway I became a great admirer of Uhlenbeck’s great clarity in putting things to someone, and proceeded undoubtedly to believe devoutly for a few years that there was no Einstein condensation. Afterwards I found out there certainly was.
Was there any particular theme of the summer session, or was it split up according to the interests of the various lecturers? Even if it was split up, was there any particular issue that everyone seemed to feel was most interesting or the important problem?
A great deal of the informal discussion –- after all, as I’ve indicated, there were all sorts of informal groups meeting, and some of them I didn’t even know about. Probably some of them I never did know about, and I only knew about Kramers, probably every night in the week had one, and I only knew about those that me on one or two nights of the week, you see. Of one that I attended regularly –- one of the informal evening sessions — the great thing was the Tarrant-Gray experiments. These were completely not understood, as you know, at that time. There was a big excess scattering of thorium C double prime gamma rays 4.7 X units, was it, or 4.7 was the wave length and 2.6 MED was the energy, and there was a big excess scattering of these things, and the heaviest elements, lead being the heaviest cheap one they could use. You know, there was all sort of talk in Gamow’s first edition and so on about –- it was a nuclear effect –- it was just about coming out then, about this being a nuclear effect. And there was also this strange doctrine that when you looked at the scattered radiation, you found lines in it at half a million volts and at one million volts.
Now, it was Oppenheimer at Berkeley, along in my second year with him then 1933-34, that Oppenheimer came up with the explanation of not only -– well, he came up piecemeal with the explanation. First he and Plessett, in the spring of 1932, had had the idea that the excess scattering was after all pair production –- the velocities of these gamma rays were pair production. Then it was perfectly obvious that the half million volt line was the ionization radiation. The million volt line was more of a puzzle, because at first there might be one quantum radiation, but nobody could calculate that it was anywhere near –- It was during the following year that Oppenheimer tumbled to the fact that the people were simply wrong about its being a line.
There was a good deal around a million volts, but they just liked lines because lines were impressive so they just made the other into a line, but it really wasn’t a line, and that what it was, was, you had all these electrons kicked ahead, and then these electrons themselves were making bremstrahlung. So this was bremstrahlung of the knocked-out electrons, you see, and it had energies in the neighborhood of a million volts, and the experimenters had simply made a line out of it, they had such a beautiful line at half million volts. After all, experimenters like to make lines. If they didn’t, some of our best spectroscopy wouldn’t have gotten done, because it’s all looking, where the untutored eye would not see a line, and saying “Look at that beautiful line.” Well, that was the thing that was being talked about so much in one of the sessions. We had repeated talks about these experiments.
Did anyone for example deal specifically in lectures with the kind of thing that Gamow would have been concerned with, nuclear models, attempts to understand the problem of electrons in the nucleus let’s say –-
I don’t remember that at that time, but I now realize that I must have got there, back there some for part of the session, probably not all of them because California began very early and I was going to California in August, but I must have gotten there for some of the sessions in ‘32, and that was the year that Heisenberg came and lectured about his new model, because the neutron was now a real particle, not Pauli’s neutron but Chadwick’s, and Heisenberg lectured about his exchange force ideas and so on. So I was there for a while in ‘32, but it didn’t make the impact on me. Except when you bring this matter up, I didn’t remember that I’d been there at all in ‘32. It’s the ‘31 one, the virgin experience, that really made the big impression on me.
In ‘32, I found a letter here from Goudsmit to Worf? Describing Heisenberg’s lectures in ‘32, saying that he didn’t think that Heisenberg’s ideas had solved the problems, which they didn’t.
Well, of course they hadn’t, but they formed the starting place for a lot of others.
I was wondering about the year before, where in fact –- if there were problems and other people were discussion them as some kind of crisis that had to be resolved, or since there was nothing much happening in that area, if they just talked about other things which seemed to be more interesting or more fruitful.
I can’t remember any puzzle being talked about except the Tarrant-Gray one. But as I say, I certainly wasn’t getting to all the meetings. They did sort of channel each series of meetings around a particular topic.
You mentioned the notes on Pauli’s lectures. What was the general theme of his lectures?
The main thing I remember his talking about –- he undoubtedly had some others, but the topic that impressed me, probably one of the first ones he took up, was the model of alpha decay, penetration of the barrier, and that was my first introduction to the W. K. B. method, and that Pauli said that he would now use the Wentzel-Kramers-Brillouin method, and I had never heard of it before, and he said it in a rather slurred way with the emphasis on the German third, and the Frenchman’s name really slurred, and I got it down as “Wentzel-Kramers-Rigmer” method. Of course, I’ve been concerned about that in so many ways, and eventually became an expert on it in a small way myself. I don’t remember just what I heard about it. Probably my memory of hearing Uhlenbeck explaining some of the things about the dates from many years later. How much of it I grasped in the summer of 1931, I don’t really know. But I got it down anyway and I think somebody corrected my “Rigmer.”
Made in more rigorous. You’ve summarized the meeting – did it give you a taste for what theoretical physics was about? (off tape) Do you have time to go on another hour?
Yes, I think I would.
We just completed the 1931 summer school, where I was summarizing what you said about exposing you to a broad range of concerns of theoretical physicists, seeing what their methods were, being involved in conversations where ideas were being worked out. Now, when you went back, you still had a final year. That was the year you were on a $500 scholarship so you had full time for your dissertation.
You said earlier, at the end of that time -– I’m not quite sure when during that year -– Loomis advanced you for an NRC Fellowship.
Yes. This had to be done, as I remember it, some time in January or February. One had to get the various forms and get some people to write recommendations and so on, and so I got the forms, and I remember I was filling them out, of course in pen and ink. My handwriting was painfully accurate but no thing of beauty, and I got very crowded at the ends of some of the lines and made rather as botch of it. I said to Loomis, “I’ll really have to get clean forms, do this over,” and he said, “What do you think this is, a handwriting contest? We’ll send it to them the way it is.” He got some rather distinguished people I think to recommend me. In fact, thinking back, I suspect that he probably had loaded my preliminary committee maybe with people that he hoped I’d make a good impression on, so he could use this as ammunition on his recommendations. I don’t know. That would certainly be a technique to use.
Who were the people?
I’m not sure. I remember that Roger Adams played some role in this. Now, I don’t remember whether he was on the selection committee and Loomis got to him privately, or whether he was simply someone that Loomis got to write a recommendation, and if he did he must have sort of stacked some sort of a contact beforehand in which Adams would have some basis of it, at least say, “I’ve seen him.” I don’t remember any other name outside the department. Naturally my thesis director would have to write a good recommendation. So then the application was in the works, and in the spring of 1932, I took a long sleepless car ride, along with some of the other people from Illinois, and got to the Washington meeting, which was a big experience for me. It was the first time I’d ever been East at all. At the Washington meeting various things happened. I’d already been to Chicago meetings and that sort of thing before, so I knew something about the Physical Society meetings. I was very impressed with the atmosphere of the Washington meeting.
You may not be old enough to remember, but you surely have heard that before World War II these meetings were a thing of charm, held at the National Bureau of Standards buildings on the outskirts, a lot of time spent on the lawn hashing things over and so on. This was very interesting, and it was interesting some of the people you met, and I was interested in seeing some of the younger people who are now on or have recently been on National Research Fellowships. Clarence Zener in particular was there and I remember meeting him. I knew his name because he was one of the authors of a paper on atomic wave functions which formed the basis of some of the work I’d been doing with Bartlett. Also, people talked to us –- I was at lunch with a group including Professor Kemble of Harvard, and at that time I was actually being also pushed, in case the other thing didn’t jell, for possibly an instructorship at Harvard.
At least, I don’t know whether there was anything to it at that early stage, but at least there was an interest in having someone from Harvard see me. Perhaps I might indicate the reputation that I sometimes had, among the people around Illinois, humble as I usually thought myself to be, it nevertheless is a fact as I remember it that one of the professors who was there, Professor Paton of Illinois, said to me before this luncheon with Kemble, “Now, please don’t go in there, Wendell, and start telling Kemble a lot of different things where he’s wrong, and explaining everything to him, and being too high and mighty. Remember, he’s an important person and we’d like you to make a good impression.” He made some little speech to me like that. I can’t really believe that in my rather downtrodden position at the time, I was capable of that sort of action, but maybe I was. At any rate that’s the sort of thing he said to me. Also it was at this meeting that I got the definite information that I did have the fellowship, so I didn’t have to worry about it.
There was no question, there was some little interest in the possibility that maybe I might or might not, might perhaps skip the fellowship and they might push me for a job at Harvard then. But I certainly never took that seriously. If I had this fellowship I was going to go. Then there was a bit of question as to where to go. That of course had to be indicated, and I’d indicated two possibilities. I had been told by both Loomis and Bartlett that the two outstanding possibilities were, to work with either Oppenheimer on the West Coast or Breit on the East Coast, and so I’d put both those possibilities in my application. I had never seen Breit. I don’t believe I’d ever met Breit at that time, unless he maybe was briefly at one of the –- either the ‘31 or the ‘32 symposium. I had seen Oppenheimer a little bit at the ‘31 symposium, I believe it was, and had not understood him. I had seen the famous scene which the author of that book doesn’t really report completely accurately –- the scene where Pauli kept interrupting Oppenheimer. He was trying to explain something at the blackboard, and Kramers finally said, “Shut up, Pauli, and let us hear what Oppenheimer has to say. You can explain how wrong it is afterwards,” or something like that. Now, I’m not sure whether he put that last in or not, but of course everyone knew that Pauli would explain how wrong it was afterwards, whether Kramers mentioned it or not. I have the feeling reading that -– of course, it’s always possible that this author picked up other people’s stories. This must have been mentioned by lots of people.
No, he didn’t complete the story like that –- this happens to be right in this section.
Well, an example of my greenness at this 1931 symposium is that Pauli started showing up with a broken arm, and it was mentioned that well, he had slipped on a wet dock while swimming and broken his arm, and it was years afterwards that someone told me that that was just a cover story, that Pauli had actually fallen down stairs while drunk at a party and broken his arm. So I was completely kidded, one time or the other.
Fermi wasn’t at this meeting, was he?
No, Fermi was so much later.
He was at an early one, 1930, but then I guess it was later.
I think 1935 or ‘36, Fermi was there.
I remember a picture, Fermi with a big patch over his eye —
— that was ‘37 —
— which was a sporting accident, in that case, a tennis ball hit him —
— no, I don’t think I remember seeing Fermi with a patch over his eye.
Let me get back to the application. You indicated, Oppenheimer or Breit, based on the recommendation of Bartlett and Loomis. Had you or they contacted either of those two gentlemen?
I suppose probably so, yes, I mean, that was the custom I believe, in asking for a fellowship, that you would say “So and so has indicated a willingness to take me.” I’m pretty sure that I did it. Well, after I had the fellowship, the question came up, which, and I asked Bartlett what he thought, and he said, “Well, I don’t think I’d miss the California climate if I were you,” so I decided to go to California. Certainly a more attractive place to live.
Didn’t you have to indicate as problem?
Well, the problem I indicated was: collision problems in nuclear physics. And while in the years that followed I sometimes messed, in fact I very often messed with collision problems, I messed very little with nuclear physics. But this was sort of a half-baked notion as to what would be interesting in the future, and of course they were both interesting in the future, and one was related to the other to a certain extent. I had very little notion of what a problem would be, and what any specific problem would be, and I said so frankly. I said I hoped the person I worked with could steer me onto fruitful things, but I mentioned a paper by Taylor that had appeared in the Royal Society in which he found this remarkable knock-on effect, in I think it was helium-helium collisions, maybe it was helium-hydrogen collisions, in which a remarkable number of the particles were projected forward rather more isotropically. And suggested that it was as if the alpha particle acted like a flat disk when it was in motion. Of course, I was stupid enough to be willing to swallow that as a possible model, but Loomis pointed out to me that it was in conflict with relativity, and Taylor had of course accounted for it by a simple potential well thing, showed that if you added a very crude model nuclear field onto the Kudon field, you could get such an effect.
With a camera?
No, this was –- no, GI I don’t believe ever did it. This was one of the examples I remember I mentioned, showing how nuclear things could have some relation to collision processes.
How about the work of Mott? Had you been familiar with any of the things that he did?
I don’t remember how much I was familiar with it at the time and how much later. One missed a great deal of things, possibly –- partially understanding them. At that time, you may remember, there was a big excitement which went on after I was in California with the work of Rupp. Various people had not found any polarization effects, and the theory in fact I don’t believe predicted much polarization effect in double electron scattering and so on. Later the effect was I believe found by going to higher energies and using heavier materials and so on, one could find some polarization effect. On the other hand, Rupp had large effects –- I think it was in this particular problem –- Rupp had large effects in some electron scattering problem, and it came out some how or other in California –- it was found out that Rupp had simply been faking his results. This was a case of complete cheating on reporting research results. One of the few cases ever known, I guess, when it was done so completely. I knew almost nothing. You can scarcely believe how ignorant I was about all sorts of things that ought to be involved in what I was doing. I knew essentially nothing about group theory at that time.
You were in good company.
Although it was the basis of a good deal of the work on molecular structure, which was supposed to have been my subject. When I read a paper where group theory was used, I just sort of hoped I could understand some of the sentences that weren’t about group theory, and waded on through. It was while I was a National Research Fellow that I read Wigner’s book. I spent a large part of my time as a National Research Fellow not really doing research, although I did quite a lot of that, but I also spent a good deal of time simply learning some of the things that I had been completely ignorant of, or learning better some of the things that I had only a smattering of. I read very heavily in Wigner’s group theory, and also I practically wore out a copy of the first volume of Courant-Hilbert during that period.
On the application, for a minute –- I’m curious about the tie-in with nuclear processes, because there’s nothing in your work at Illinois that would indicate that.
Oh no. I mean, this was a complete change. I was quitting those molecules –- quitting them for good. I had, of course, just as a member of examining committees and so on, I’ve used a little of that background ever since, been involved –- you know, any background you have you call on, on occasion. Mine is certainly very ancient when it comes to molecular energies. But I certainly quit any active work on that the day I left Illinois.
I’m curious about the interest in nuclear problems, even though not a direct interest. There were certain events, just about that period of your submitting your application –- I wonder if they had any influence in focusing your attention. For example, the neutron was announced in February, ‘32.
Yes, that was probably just about the time that the application had to be in. I don’t remember whether I mentioned the neutron or not, as I don’t remember whether it was even out yet at the time that I put the application in. The one thing I remember putting in as an illustration of the fact that I had read a paper and had a thought was this thing of Taylor’s about the helium collisions.
Do you remember any discussions at the April, 1932, Physical Society meeting on the neutron or similar results that Cockcroft and Walton were just getting at that time? Was there anything on that that impressed you? I could check the program to see if there were papers on that.
I think being in Washington, seeing all these people and so on, made the biggest impression on me. They must have talked about that. Somehow or other, that particular Washington meeting doesn’t have any scientific residue much on that. I got loose I remember one day when I should have been at the meetings and wandered around Washington, got into the Senate, say Huey Long in action. I was perhaps in a bit of a holiday mood. I got there, I got to see very interesting people, I got to see some recent or present National Research Fellows, of whom I hoped to be one of that select breed, in the flesh, and I got to see some of the sights of the city and as I say even visited Congress one day. I guess all this excitement wiped out any specific memories, but they must have been talking about the neutron.
Yes, I can check the program; I was just curious.
I have much clearer memories, for instance, of being at the meeting in 1939 and hearing Szilard and others talk at lunch privately about what this might mean about the possibility of explosions and so on. This comes through. But what I heard about physics in 1932 –- I remember what Paton said to me before that lunch with Kemble. I remember some of the personal things.
That was more important. Well, I want to get back to this Szilard business later, but getting back to the point at which I interrupted you, you said you had to choose between Oppenheimer and Breit and the advice you were given was, try the California climate. So I gather it was a simple decision.
Yes, California –- I mean, I think it was a wise decision, for me. I had no experience of urban life and so on, and I think California was a lot more hospitable place for me at that time that New York City would have been. Of course, it was exactly at this time that John Wheeler made the opposite decision and went to Breit, and then afterwards went to Copenhagen. So I can’t say it was impossible for somebody else to do better by going the other way. But I think probably it was the right decision for me.
According to what Raymond Burge has written in his history of the department at Berkeley, you were expected out there about August 15th –- at some points he’s very precise.
Yes. August 15th was the announced date that it was open and I got there probably a couple of days before.
He didn’t say when you arrived but when you were expected –- this is quoted from his report, I guess his annual report.
There was probably an exchange of letters. I was probably informed that that was the beginning of the term, and I probably indicated I’d come then, and I must also have had to inform the people in Washington, the National Research Council, that that was when I wanted the term of my fellowship to begin, you see. I do remember that when I got out there, I was supposed to receive payment on this fellowship in advance, and I ordinarily did receive it promptly in advance this month, but there was no money for me when I got there, and I had to borrow a modest sum from Oppenheimer to tide me over until it came. That was an interesting experience again also when I shifted from NRC to Harvard, and Harvard in those days began September 1st and paid in advance, and I had been paid in advance on July 15th for my last month of the fellowship. On this occasion I borrowed from my brother. Well, I can well remember that Oppenheimer invited my wife and me to lunch at the Faculty Club, as soon as he knew we were in Berkeley, and I don’t remember whether we actually had lunch on the balcony of the Faculty Club, I mean on the porch, or whether we only talked on the porch, but it was there on the porch or whatever it is of the old Faculty Club in Berkeley that Oppenheimer said, “Here comes Lawrence, and he just got particles out of his big magnet.” As I mention in my book, I didn’t know what the big magnet was. Of course I had to find out very soon. I guess that was only a rather a short time after Livingston and Lawrence had managed to get anything of that sort to go. And then Lawrence got hold of this big old junk magnet, essentially, and built a bigger model, and was just getting it to work.
How did you get settled there? This was quite different from having specific duties as you had as a graduate student.
Well, after all, I had of course been taking a course, even in my last year, this course in statistical mechanics with Mott-Smith, but it wasn’t too big a change in that respect. Everybody sat in on Oppenheimer’s lectures as a matter of course, in his course in theoretical physics. I don’t think they were as smooth as people of later years remember them. There was a good deal I didn’t understand, and a good deal he presented in a slightly –- in a much more highbrow way than was presented for example in the lectures that are reproduced now, of somewhat later years. But I was sitting in on those, along with Dodowski, Carlson and Phillips, his recent PhDs, who were all still there because there weren’t any jobs. On the other hand, I was expected of course to spend most of my time on trying to get started on some sort of research. There were also a good many meetings. I mean, the number of special meetings and colloquia and seminars that they had there in California would now seem small –- many of the institutions are carrying on a lot of work –- but at that time the number was still small enough so that it was more or less expected that you’d go to practically all of them, and this seemed to me to be far too much of a burden. I mean, I rarely understood anything that was said at these rather specialized meetings, and I found them interrupting my own efforts rather inconveniently. I think I finally got up the courage to skip some of them.
These were the formal ones with guest lecturers.
Well, not necessarily guest lecturers. They might be some local person. It was the sort of thing they’d have every week, some talk or other.
I think little cards would be put up on the bulletin board, announcing.
Then of course they had what we called the department meeting at Berkeley, called colloquium at some places, which was a colloquium on more general subjects. I don’t want to imply that I ever wanted to skip that. But there would be various special seminars and so on, taking up some more hours in the week, and it was these that I more or less wished there weren’t so many of.
What about the Journal as it then existed?
That met I think on Monday nights, and that was very interesting. And it was at that, some time along in the middle of the winter, that we heard that Anderson had found these strange particles, which were the positrons. And of course, we had to make reports ourselves on various papers. I remember being assigned a paper by some second-rate German, whose name I won’t try to remember accurately because I might get it wrong and insult some respectable person -– but I was asked to read, and I found it almost impossible to make any sense out of it at all. But what I did manage to do, in my stumbling and rather terrified report, was to bring out one of the points on which I hadn’t been able to make any sense, whereupon Oppenheimer simply exploded – “Well, obviously the guy is talking complete nonsense, if he said what you just now reported. You don’t have to try to make any sense out of it. He’s just a dope, so let’s drop this subject and go on to something else.” Which was a great relief to me.
You were his second NRC student.
Yes, Hugh Wolfe was his first, I believe. I don’t think he’d had any other before that.
But his graduate students were now also post-docs.
They were post-docs without stipend, that’s the sad part of it. There were very few post-doctorals with stipend in those days. The NRC gave, I don’t know, six or eight fellowships, each year to new people, perhaps and renewals for a second year –- very rarely anything beyond that. Then the practice of various institutions of financing post-docs and so on just didn’t exist. So it was a very different from what it is now. I was in a very exceptional position to have this source of support.
You came there to work with Oppenheimer. What did that mean, in terms of the nature of the relationships?
Well, it meant that he would take an interest in me. He was generous in his interest in people there. It meant of course that he had to find out during the early part of the period how dismally ignorant I was about some things, about a good many things, that he had to assign me something to do –- you know, something I could at least study up on. And I remember what it was. It was a paper by Waller on scattering. And I think it was a paper in which Waller derived the Klein-Nishina formula. Maybe not. I think it was probably the Klein-Nishina formula derived –- but I may be wrong on this, because Bethe and Heider published a derivation –- no, I guess theirs was electron scattering. I mean, not Beth and Heider, Bethe and Kermi published theirs on electron scattering, the quantum electronomical methods. I think Waller’s was on the Klein Nishina, on scattering in general with that as one of the examples.
The interesting thing about this is that methods of work were not as highly developed as they might have been, in various ways, among lots of people in those days, and actually, I found Waller’s paper very difficult. I was plodding along through it, trying to make something out of at least one page a day. Oppenheimer eventually made sarcastic remarks that I was proceeding “adiabatically” through this paper, that being one of the favorite words in those days for something that went very slow. I realized afterwards, years afterwards, that one of the things that I didn’t understand in that paper was essentially Waller’s way of doing something very close, at least, to the famous trace technique of calculating spin sums and so on. Which was first very clearly explained in Bethe and Heidler’s paper on the pair production, but which is commonly attributed, I think, to – no, I guess not. Is it Casimer? Somebody — Well, the germ of it, enough of it so that somebody who was really keen, as I wasn’t, should have been able to catch onto it, was in Waller’s paper, and the interesting thing was that Oppenheimer and Carlson were just finishing off the publication of some work which I believe part of it had been Carlson’s thesis on collisions with high energy electrons and magnetic neutrinos — you know, Pauli’s neutrino and Pauli’s neutron — I guess it was called magnetic neutrons.
This was still before the neutrino. Pauli’s neutron, he thought, well maybe it doesn’t have any charge but maybe it has a little magnetic moment. And so these light particles with the tiny magnetic moment — Well, in this paper, they sweat through the calculation of all the separate terms and all the matrix elements, by using the actual values as they were written out in Fermi’s “Reviews of Modern Physics” paper at the time, the actual component values for components for the direct wave function in each spin state. This was all done out, the actual algebra in their paper, and it was just this sort of thing that the trace technique was to render unnecessary, you see. So it was a bit ironical, it seemed to me later, that the paper that Oppenheimer urged me to, for God’s sake get through with that quicker and let’s do something else, I afterwards realized had contained enough of the idea of that so that if one picked it up and really worked on it, one could have got the technique ready and really used it — as Bohr had effectively used it. I mean, he hadn’t made it very clear what he was doing, but he had effectively used that sort of technique in his calculations.
We all went on, out there, during the rest of my time, doing these calculations rather crudely. I did invent a way to short of shorthand it to some slight extent, which Carlson referred to humorously as “using complex vectors in Furry’s face,” but it was still very difficult. Hugh Wolfe had had a way of trying to shorthand these things, while still not accomplishing very much real economy. But this trace technique was a fantastic economy, and it burst on me with revelation when I saw it after I’d been at Harvard a few months, when Bethe and Heidler’s paper came out. So later on, around 1947-48, when the newer generation got to talking about the pedestrian methods, referring to the old methods, I used to tell some of the boys that I remember when we crawled on our belly, without even walking on our feet, to do these things.
What was the relation with Oppenheimer in this sense? Did he assign that paper to you?
Yes, he told me that I might as well read this paper of Waller’s and see what I could learn out of it, and unfortunately I didn’t learn enough, you see. I didn’t learn the thing that was really sort of waiting there for somebody to get hold of and use better. Now, just why that never came to be associated with Waller’s name, why he never taught a group of people to use it well enough so that it would come out, I don’t know. It was — first got out, first really got into general circulation and got generally understood through Bethe and Heidler’s paper about 2 ½ years later.
when you were working on, not necessarily that paper, a paper that Oppenheimer had suggested you read, would then the idea be to go back and tell him what you’d learned?
No, I can’t remember –- he just said, “Have you got through reading that paper yet?” He may have asked me once or twice what I found out about it. Then he said, “Well, you might try some calculations.” So he thought of a calculation for me to do, and I can’t remember exactly what it was, but it was of course interaction of radiation with an atom and probably also giving off an electron, but there was some strange arrangement here whereby one was trying to get an effect, and the final conclusion of our thoughts on the matter was that the effect didn’t exist. If didn’t exist because while you could find large matrix elements for it, if you wrote all the matrix elements out for it, they always cancelled. And this is one of the cancellation effects, one which I don’t think anybody ever did write a paper on. There was another cancellation effect later on, on the Spurries(?) theorem, but this wasn’t that. But this indicated then that there wasn’t really any phenomenon here. That happened after I worked on that for a number of weeks.
Then he eventually suggested that Carlson and I might collaborate on working on the collision of electrons with the emission of radiation, and this was an extremely difficult problem, especially when you didn’t have the more powerful techniques that were not generally known until a couple of years later, and which we had no real inkling of at the time, although I ought to have got it out of Waller. We worked up a lot of formulas. We found out some very interesting things about it, but we never got it to the point where we could calculate. The equations were just too heavy. We did get up to a point where -– which was about where Moller got to, a year or two later, in a paper that he published on it in the Royal Society. He published a paper in which the calculation wasn’t finished but he’d just gotten it to a fairly neat point in the formulation. We had got about the same point, but had felt that we ought to go ahead and get the answer, and had never been able to go ahead and get the answer. As I guess nobody ever did with that particular problem We later used a bobtailed version of this to calculate the pair production by electrons, in collision with nuclei, which we published as a sequel to Oppenheimer and Plesset’s paper on pair production. But we never got the original calculation finished. Well, I could tell you these anecdotes, about the way things were done, anecdotes which I’ve told to a good many people but have never gotten in the archives, I believe.
I would like to hear that, and I’d like you to talk about the circumstances, the day to day life, and I think these anecdotes would tend to carry the same information, too.
The way it worked, the way this happened was this. People got to talking in the beginning of 1933 about the observations of the positron in Pasadena. Incidentally, that was one of Oppenheimer’s little foibles. Positron is, from a linguistic point of view, a terrible word, because it starts with a Latin syllable and ends up with a Greek syllable, and Oppenheimer resisted if for quite a while and insisted on calling them “positives” instead of “positrons,” but of course Anderson’s view prevailed, as could be expected. So the papers Oppenheimer and I wrote the following year about the general theory of it, it was called “Theory of Electron Positives,” followed by some further remarks in which, in a letter to the editor, in which the word positron was used in concession to the wave of the future. Anyway, it was his custom to go down in the spring of the year to Pasadena, and spend I don’t know, three or four months at CIT, AND he didn’t encourage his students to follow him immediately. He perhaps sensed that we needed a little relaxation from his pace. I don’t know just what it was, but he suggested that I should come down you know maybe six weeks after he had gone down or something, so Frank Carlson and Betty and I got in a car which I had bought for $175 –- or Betty and I had bought jointly, because we certainly both discussed it very carefully, this major venture –- we went down in a 1929 Chevrolet that we’d bought for $175 with Frank as our passenger to Pasadena, and took in a day or so of Yosemite on the way, the only time I ever saw Yosemite, as it turned out, and then we got down there and Frank and I were assigned a room where we could go ahead with our calculations, which we were struggling with, on this radiated collision of electrons business. But then Oppenheimer got the notion, “Why don’t you apply some of the same general principles and ideas you’ve been using onto a problem which really is almost comes from transformation, namely, the pair production by electrons striking.” So we did, and we got it down to where we were ready to make the calculation, to make the final integrations.
Then we ran across the difficulties that one was going to run into, with these integrations. So we consulted Oppenheimer and he showed us what he and Plesset had done, and the situation is this. You either have a gamma –- well, the simplest case is that of a gamma ray strikes –- is coming near a nucleus, so to speak, and it turns into an electron pair, but the electron and positron have proper mass, and to pay for their proper mass, together with their kinetic energy, costs just a little more than the energy from the gamma ray would have for the same momentum. What happens is that these two particles have a little bit less momentum than the gamma ray, and that’s taken up by the nucleus. Now, this is absolutely necessary in order to satisfy the conservation laws. What happens in practice is that a lot more momentum than that is given to the nucleus, but it’s given to it transversely. But this longitudinal bit is absolutely essential to get the thing to happen energetically. But it’s terribly small at high energies, and becomes smaller and smaller at high energies. Now, to include this longitudinal bit in the calculations made the integrals very difficult. On the other hand, if you left it out, tiny thought the quantity was, this was a falsehood of sufficient size to make the integrals all diverge. On the other hand, Oppenheimer had other thoughts. It was believed at that time that matter, including heavy matter, including lead, was extremely transparent, remarkably transparent to cosmic ray electrons. It was in fact hard to see how they had even the Klein-Nishina loses, let along any large extra losses. And it was very evident without doing the calculations that if you kept the thing just as it stood, that there complicated integrals, you could estimate them and they were bound to give huge values at high energies.
The experiments seemed to contradict it. So Oppenheimer formed the view, which was then a matter of discussion back and forth between him and Nordheim and others for years to come –- well, two or three years at least, it seemed a long time then, it wouldn’t now -– as to possible breakdown of the general theory. Now, Bohr and other people were involved in these arguments. Bohr had doctrines using Lorentz transformation to show eventually that it couldn’t happen except at these enormous energies. But this was in Oppenheimer’s mind. And so he didn’t believe this integral, if you kept this tiny term, and integrated out it would give a huge effect. So he said, “Just leave that out, that will make the integration easy.” But of course what you then end up with is an integral of the form, integral roughly, integral DXDY, over the absolute value of the difference of X and Y, integrated over a certain area of the XY plane, which definitely included a good-sized chunk of the line X = Y. He said, “Of course we know this. By leaving that thing out, we know we’ve made it infinite, of course. But we know that the theory must have to break down. It couldn’t be that large. It couldn’t be as large as it would be if we hadn’t neglected the term, hadn’t made it infinite. So here’s what we do. We’ll simply replace X-Y with X+Y and that will give us a good estimate.” That was just what he and Plesset had done, and so it’s just what we did, and the interesting thing is, both these calculations were published just as Letters to the Editor in the PHYSICAL REVIEW. It was stylish in those days to say things that people couldn’t possibly understand and put them in the Letters to the Editor so you could be sufficiently brief. And they were published with the = sign between the letters sigma, the cross section, and this formula that had been obtained with this amazing procedure, of which not one word was breathed in the Letter. This was all private, just between ourselves. Some months later I said to Oppenheimer, “It really was a little bit bad to use the equals sign in there,” and he said, “Oh, I didn’t want to put one of these things in there with the wiggles. Everybody figures, if you put that in, you’ve just counted up the powers of E, and just indicated, figured how many times the fine structure count matters, but just sort of counting up on your fingers.” He said, “We’ve done lots more than that.” “Yes, but,” I said, “the equals sign isn’t really the right thing to put, when you have made these changes.” He said, “Of course not. What we needed was, not the sign that would lead people to suspect that we hadn’t really calculated anything but had done a –- just done a simple little dimensional argument, sort of a matrix on the counting. What we needed was a sign that would mean, we made a serious calculation and this isn’t what we got.” At any rate, that was how that was done, and the PHYSICAL REVIEW still contains it, and it resulted in a constant cross-section of high energies for the gamma rays, and a logarithmically increasing cross-section for the electron collisions. But the correct calculations, as done later by other people, by Bethe and Heidler, by the exact same methods but without any neglects or any fudging, and by other people with the problem Carlson and I worked at -– that’s a little bit too hard to solve completely by that method, I don’t think anybody ever did succeed –- it was done by the Weiszacker-Williams calculations –- it gives double. If you do it right, so to speak, the gamma rays –- well, if you do it right, period, as the theory tells you to do it, the gamma rays get logarithmically increasing, and the others give square of the logarithm –- until screening cuts it off. The screening cuts it off only at large energies. Of course, the secret was, the experimental effects that were keeping Oppenheimer from believing these cross-sections were the apparent radiopenetration of electrons. The explanation of the experiments was that most of the cosmic rays at seal level weren’t electrons at all, they were murons. That’s what was going through the lead plates so regularly.
1933, that’s pretty early.
That wasn’t suspected, because if you did believe –- and one reason for not suspecting that was that if you did believe that the elections had this high interaction, why, it simply was incredible not only because you did see things going through but also because you didn’t see lots of showers coming out. The showers, you didn’t see the sort of showers you’d expect, that is building up nice and smoothly in numbers of particles and looking as if they’d been produced at various distances back in the lead and so on. The showers looked as if they came often from explosive events. And of course some do, some nuclear showers, but these electron showers, that was an illusion. On that fluctuation calculations were needed, which I more or less pioneered a few years later. Essentially the trick is here that although the fluctuations are enormous and even a thin piece of lead, where the average number of secondary particles produced may be only two or three, there’s an amazingly good chance that 15 or 20 might just pop out. Enormous compared to what you’d just get from the Poisson law. Also, when they do, it will be because the first few that got produced in here was particularly fruitful later on, so that most of them did get produced right down to the bottom millimeter of it. I mean, this sort of thing came out later. So various things – the presence of new mesons, the failure to understand how important fluctuations would be, were keeping one from realizing what was going on before one’s eyes, and this led to these calculations. Now, this never was of course made clear to the general scientific community, just what the hell had gone in in these notes by Oppenheimer and Plesset, and by Carlson and Furry.
Did anyone pick them up at the time and challenge?
Oh well, of course later on people got answers that didn’t agree with them. Well, it just looked as if we’d been wrong. Of course we had been, but we were wrong at a very sophisticated level. But this problem then, about, does the theory break down at high energies? –- this went on. This went on through 1936 or so. And Oppenheimer kept maintaining it would and Nordheim kept believing it wouldn’t, and Bohr provided arguments based on Lorenz transformation, which indicated that there just couldn’t be enough high energies really involved, high frequencies really involved, to count, to produce the effects of Oppenheimer. You could go to Lorenz transformation, when frequencies were low, see, to to alliance reference range where the frequencies were low. Oppenheimer got around that by saying, “Well, even if there aren’t enough of these very high frequencies really present in this special frame with Bohr to produce much effect, even though they’re not responsible for the effect, still their presence may somehow poison the phenomenon, so that the lower frequencies can’t do all they otherwise would do.” He was straining harder and harder. And of course, he himself was the first one probably to tumble to the fact –- my impression of this may be colored with the fact that it’s the first I ever heard of it was a letter he wrote to me in which he expressed the idea –- certainly it hadn’t been in the literature until quite a long time after I got that letter from him –- he alluded to the fact that autonomous particles (of course this is dead wrong, because they’re pions) – but still, that something of the weight, about the weight of Yugaga’s(?) particles were really making up most of the cosmic rays. And that was right, and Oppenheimer was, so far as I am able to see, probably the first man to see it.
When was this?
It was some time around 1936, and it was directly based on that then that in the next year, around 1937, I published a paper on the fluctuations, which was a crude thing, done with very strong approximate guesswork methods, but which had the main idea in it that the fluctuations are large. They are not plus-omo sort of thing, which is the sort of thing that Bethe and Heidler had done. And of course they shouldn’t be plus-ohm? –- because if one pair has been produced, or one…, that increases the chance for further events. See, things are coupled. The plus-ohm is assuming independence in all the events. This is definitely a chain reaction. The events are coupled, and so the fluctuations must always be much larger than they are with plus-ohm. Well, some of these things gradually got worked out.
You pursued that on your own when you left. This was the kind of an issue that you could do independently, and it didn’t require close collaboration on.
Yes. Well, our second year, my second year there, and let’s see, I’m not sure whether Frank Carlson was still there the second year, because he went to Princeton at some point there. See, Princeton at that time, not Princeton itself but the Institute for Advanced Study, developed something along about that time which would help to relieve the distress of unemployment among physicists. I mean, this unemployment was striking somewhat the way the unemployment does now. It didn’t hit only the young and green, it also hit the more experienced people — if they happened to, say, finish up their fellowships that they’d been good enough to win, but no job opened, well, wham. So, the Institute for Advanced Study developed this system of giving very small stipends to a good many younger people, just in order to I mean, it was awfully good for the Institute to have them there, and it was a life saver for the young people. Oppenheimer got Frank in on one of those for a while, and Phillips went on one of them too, and other people were there. Clarence Zener, whom I had admired so much, who was several years ahead of me, landed there for a while on one of them, and it was he I think who coined the expression for his stipend, “my monthly insult.” So I’m not sure whether Frank was there much of that second year. But I think he was there at least the first half of it. It was during that second year that Oppenheimer picked up this notion of writing a general paper on the subject, of the general theory of pair production. This paper is long since obsolete. It was naive and defective in certain respects, and aroused great doubts immediately among some of the real experts like Wigner and so on. But still it represented the first major effort to reformulate this thing, the sort of thing which has finally eventuated in present electrodynamics. Oppenheimer chose me as his co-author in that, for the reason that I had kept asking him questions, instead of contenting myself with saying “how fine” whenever he announced anything or made any argument — fast argument that was much too quick to follow, and wrote a formula on the blackboard and said “This is it” — the custom was to stand around and say, “Excellent, fine, how illuminating.” Which was in a way a reflection to the way Oppenheimer reacted to our approach, you see. This guy has a slightly garbled version of this. I’m giving you a fuller account.
You mean Micklemoor.
Yes, Micklemoor has the comment that the Glen Camp finally comforted me for showing up, and he was one other guy who would admit that he didn’t understand what was going on. Well, there’s some truth in that. The situation was that this wasn’t all just hypocrisy, this was to some extent a feeling that they owed it to Oppenheimer, because whenever one of us would make an effort, he would always be so complimentary. I can remember trying to repair a talk to be given at some meeting, perhaps at the Berkeley department meeting or perhaps some other group, and having a rough time of it, and knowing damn well as I finished my talk, knowing damn well all the way through it, that I was doing a lousy job — that it was confused and poorly delivered and just really a rotten talk — and having Oppenheimer just come up afterwards and say, “That was a splendid talk, Wendell,” and so on, and “we’re so glad that you presented it to us.” Well, he did this to all of us. He praised all of our efforts even when we weren’t so hot. And so to some extent, this was a reflection. When he would express himself somewhat obscurely, and very quickly, with flashes of insight which we couldn’t follow, and then everybody would say, “This is fine, and this made it all very clear,” and I would say, “What about —?” and ask a question. Well, he revealed to me that fall that impatient as he had often been at my questions, he valued my asking them, and so he wanted me to collaborate with him in working this thing out.
Because the questions forced him to think through things?
Yes, I mean, the questions would sometimes make him think again. There’s a famous story the professor used to tell… (off tape)
When you collaborated with him on that paper, was it a question of writing it together, or of —
It was a question largely of spending many hours talking about it at the blackboard in the lab, and probably even more hours pacing the streets of Berkeley, arguing about it. During a great deal of this, I didn’t understand what he was saying, but every now and then I would try to express what I thought might be my reaction to what I thought he had said, and sometimes he would find this valuable, and we kept on this way. There are also of course some matters of detailed calculation in the paper, a good many of which I made, thus feeling I was able to contribute something. There’s also, of course, occasional bits of calculation that somebody else made and supplied. Melba Philips made one calculation, I remember, which is quoted in the paper, for which she is thanked in the acknowledgements. So that was a really heavy bit of collaboration, in which I always felt that I wasn’t able to react anywhere nearly as quickly as he did, and often not to understand what he was up to at all. And then of course he came back from an Eastern meeting and told me some of the objections that other people had had to it, and that made it seem more confused than ever, and the objections were to some extent right. I mean, we had brushed aside questions of Lorentz gauge variance which do become very difficult in this theory. I mean, after all, we never got fully straightened out in another ten or fifteen years.
This sequence of papers seems to be all of one piece that you were working on the same type of problem. This was more or less continuous –- you’d get something and pick up another thing on the same line.
Well, I wouldn’t say that. What I was doing with Carlson was straight calculation, you see, except when it was made crooked from suggestions on how to finish the last integration, but it was largely a matter of getting a mass of algebra done, based on a physical idea. Whereas this paper with Oppenheimer was much more a matter of probing around about the basic ideas of the subject — something which we did very crudely and which has lapsed into a deserved oblivion, but it was the first of a long succession of efforts which finally have given out a good theory.
What I mean is that they weren’t so far afield, though the styles of work were different.
Oh, the styles of the work were entirely different. It was all about positrons, that was the —
Who else were you in touch with at the time who was working on the same thing by this I mean, whose papers you read with interest, with whom you might have some private correspondence or personal encounters?
Well, there was Plesset, and Plesset went to Copenhagen the next year. He had originally been from Yale, and he was in Pasadena the year I was at Berkeley. Then he came to Copenhagen, or at least came to Europe and spent some time in Copenhagen, and he wrote me letters telling about what was doing on over here, and it was from him that I first learned that Zelter had actually been able to get the integrations all through. This is interesting, because although I had this information straight from the scene of action that Zelter had succeeded in completing the calculation, it was Bethe and Heitler who published them. So Zelter must have been somewhat self-effacing man or else a very lazy one about writing up manuscripts.
Where was he at the time?
I don’t know just where Zelter was. You know, Copenhagen at that time was the nerve center for communication, as it perhaps still is to some extent, for people working on this sort of thing all over Europe. So I don’t know exactly where Zelter was sitting when he was supposed to have got this finished, according to Plesset, Heitler had been working on this sort of thing before. I hadn’t met Heitler then. I didn’t meet him until quite a number of years later, after the war, I think. Heitler had been working on collisions, on radiated collisions of electrons of nuclei, and this of course is just interchange of positive and negative electrons, that’s all you need to make this into pair production. And of positive and negative energy quanta, too. He’d been working on it for years. His papers were coming out at least as early as my first bit of time in California, and he and Bethe finally got this thing out some time early in 1935 or something like that. Oppenheimer never had too much sympathy for Heitler’s work, because Heitler was sticking very closely to the formalisms, and Oppenheimer felt so sure that you had to depart from the formalisms at some point, because of this cosmic ray evidence.
He didn’t believe the interactions of energy could be as large actually as the theory said. Then there was an interesting little event that happened I think probably during the second time that we were in Pasadena. I don’t think it happened as early — that was some communication with Weisskopf. Weisskopf did a job at that time on the self-energy of the electron, as affected by positrons, and made a mistake in it. He got the wrong sign in the terms of the nominator, and failed to notice that what positron theory did was to remove an apparent very sharp resonance which had been present in the theory of the single direct(?) electron, and thus cut the self-energy way down, cut it down from a very strong divergence to only a logarithmic divergence. Weisskopf missed this, and in talking over his paper, Oppenheimer and Carlson and I were going over it, and we saw very clearly that he had missed it, and that if you did it right, the divergence would be — you would have the exciting result that the divergence was cut down to only a logarithmic one. Then of course the question came, what should we do about this? Well, our noble decision was to write a little note to Weisskopf. I in fact wrote the note, saying that Carlson and Oppenheimer and I had found this out. Weisskopf happily published a little correction in which he thanked Herr Furry for having pointed out this mistake.
He was probably at Gottingen at the time?
I don’t remember what his address was. It was in ? No, Weisskopf has always been a warm friend of mine ever since, as he should be. I mean, this was one of those questions where, do you needle the guy or do you help him? We decided not to snatch for a bit of glory ourselves by bursting out with this, but instead to tell the guy who’d done it first, “Look, here’s your mistake, you’d get a more exciting result if you’d do it right.” I don’t remember too much else about communications back and forth. The number of people working on the thing was much smaller than it is on many of these exciting subjects nowadays. Let’s see, there was some work done in Europe, I’ve forgotten who did it, in which they used the early calculations done by Salter and by Bethe and Heitler on this, for a check on the experiment. Well, the people in Pasadena had experimental results too which they were very eager to have something to compare them with. We didn’t know the actual formula. This was not included in anything that came across the Atlantic. I mean, Plesset said, “Salter has got it done but he didn’t tell me what the answer was.” I tried very hard and I never was able, none of us were ever able at that time, to do the integrations which these Europeans had done. It’s a real tour de force of calculus to get it through. I’d done some tours de force in my time but I never got this one done.
What I’d done was a tour de force of approximate work. I started out with the thing that was to be integrated. I could not do it exactly, it can be done exactly, because people have done it exactly, but I couldn’t, and I made two small changes in it, one which was sure to make the end result bigger, and the other sure to make the result smaller, and both of which enabled me to advance the staff. Then I came on to the next place, where I simply couldn’t integrate. I did the same thing, made two different small changes, one that was sure to make it larger, the other sure to make it smaller, and each of which enabled me to get it through. And after doing this about three times, I had it. And the two formulas were still pretty close together. So this is what was used in Pasadena at that time, for comparisons. If you look at one of the early experimental papers on quantitative results about pair production in Pasadena, you’ll find the comment that there’s a paper in press by — something like, there’s a paper in press by Bethe and Heitler on this that we did not know their formula so we used a formula provided by Oppenheimer and Furry, something like that.
It’s interesting to me —
— so one does a lot of work sometimes which does not show up in any publication. This is true of many other occasions. Of course, a lot of it is lousy work, but some of it is even fairly good.
That’s why historians like to read notebooks and letters. An interesting thing about this is that Oppenheimer’s theoretical work and yours and the others associated with you was based more on experimental results not at Berkeley but at Cal Tech.
Yes, this was definitely at Cal Tech.
Although you only spent a small fraction of your time there, the majority of your time was concerned with the issues that were touched on experimentally down there.
Yes, that’s true. I can’t remember that anyone at Berkeley during this period did anything that excited us, about this particular subject, which was the sort of thing that our effort was going into.
There were things going on at Berkeley in the early accelerator work, some of the disintegration experiments, which apparently didn’t excite you, because it didn’t relate directly —
Oh, it was exciting to hear about, but I never happened to get started working on it. It was very interesting to hear G. N. Lewis come in, for instance, and talk about his work in separating deuterium and so on, and you see, he was the one who found out that you could really do it easily, that instead of doing some fancy distillation or diffusion job, you could do it with electrolysis and have it much cheaper, and he provided of course the stuff that they used in the cyclotron. Oh, it was very interesting to hear about what went on with the cyclotron and all sorts of other things that were being done there by people. There was a guy named Sloane who built a big X-ray gadget with a very remarkable system in which the generation of high voltage took place in a transformer inside the tube, in which the tube is an enormous tank. This of course had some interesting results, if you want me to diverge a little bit from my own work. This big Sloane X-ray gadget had the interesting result that it brought out that people didn’t still understand how to protect themselves against X-rays when you change the circumstances, because they had lead shields all around to protect them, but it turned out later that some of them had a good deal of radiation damage from the radiation that went past them, behind their lead shields, bounced off the wall of the building behind, then came back. I mean, the stuff was so powerful that just scattered radiation, which is ordinarily negligible was strong enough to be dangerous. Oh, there’s all sorts of interesting things going on there. I mean, this was the period when Lawrence was really bubbling.
Was Oppenheimer brought in?
All of this was nuclear physics, the nature of nuclear physics, of nuclear forces and nuclear structure was still extremely vague. This was in fact the way I fell out of contact with what Oppenheimer was doing after I left. He did shift his attention more to nuclear physics, and I was somehow or other never able to make the shift. I always found nuclear physics distasteful. I had gotten myself a fellowship, by writing an application on nuclear physics, but when a few years later it turned out that this was the field that at least Oppenheimer certainly was moving in and a lot of people expected me to move in, I just never really got into it. I spent my life finding some very important things distasteful. I also found solid state physics distasteful.
Is it a question the types of problems that you were confronted with? In a positive sense?
I don’t think I had the ideal psychology for a physicist, by any means. I like neat problems with settled rules too well. But a physicist shouldn’t do that, you see. They have the story often told about Pauli, that someone had a problem he was anxious to get Pauli’s help on, so he found it a very difficult problem, so he explained it to Pauli at some length. Pauli eventually said something like this, “As I understand it, you know precisely what calculations you have to make and what all the procedures are, you just don’t seem to be able quite to carry it out — is that it?” The man said, “Yes, that’s it.” Pauli said, “Well, I couldn’t possibly take interest in a situation like that. The only interesting thing is when you don’t know what you have to do.” You see, that’s the idea — for a physicist, he should be interested in the situation where a large part of the job is just to define the problem. I myself have always not been a very satisfactory physicist in this sense. I like well-defined problems, and nuclear physics was a very messy subject for a long time, and frankly I suspect it still is.
Yes, I think there’s agreement on that. How did you see Oppenheimer switching into nuclear physics before you left, or later, after?
Afterwards, I would say. Of course, you see, this taste — I mean, you’re not free to follow your taste. God knows there could scarcely be a more awful mess than that positron theory was, but I got myself involved in it. But when you can see in advance that the theory is a mess, my inclination is to stay away.
Let me ask a question about the general situation. Maybe we can keep up for ten minutes more…
The general situation in the department at Berkeley interests me, because as we were just saying, Lawrence was developing his very exciting program and at the same time Oppenheimer was certainly coming into his own with a group of outstanding colleagues and students and so forth. Did you detect any differences in terms of their relative positions in the department? Was there any problem in the overall direction of the department, when priorities had to be made one way or another?
Well, I wasn’t in a position to know anything about that. I wasn’t a member of the department faculty. So I really don’t know anything about what went on of that nature.
How about Oppenheimer himself? Did he seem to take an interest, not directly in his own theoretical work, but an interest in the developments that Lawrence was getting into? You told me he was the one that introduced you to Lawrence.
Yes. Well, I don’t know. If he was working much on that at the time, he was using some of his large supply of energy at the same time that he was putting out all that the rest of us could stand on these matters which, as you say, were more related to experimental work going on at Pasadena. I have a strong suspicion that this is exactly what was happening, that he was keeping us up to our ears in effort and the same time was supplying a lot of advice and counsel on various questions to the people working with Lawrence. That would be — he’d certainly be capable of that.
Lawrence’s letters seem to bear it out, he keeps thanking Oppenheimer for advice, in the same way that Gamow was advising Cockcroft.
Yes, that probably was so. But you see, none of us ever noticed that Oppenheimer wasn’t giving full time to us. He was certainly taking up our full time.
His publications were certainly all in your area. They weren’t in the other area. Maybe there are some exceptions. Plesset was at Cal Tech for a part of the time. Was he an NRC fellow?
Yes, he was an NRC fellow, but I can’t remember anyone else who was at Cal Tech then in the theoretical work.
What I’m truing to get at here is, did Oppenheimer pick up people along the way, or was his work at Cal Tech sort of as a guest lecturer and a link with the experimental work? He really had no students at Cal Tech, no post-doctorals?
I can’t really understand why Plesset was there, because Plesset seemed to be much more along Oppenheimer’s line and I would have supposed he would have spent the time more or less in the same place as Oppenheimer, except when advised to take a vacation, as I was, by not following down at once. I don’t know quite how it happened that Plesset was spending his time in Pasadena, because so far as I know he didn’t get going on anything until Oppenheimer went down there and then they got to doing this on the pairs.
The closest tie experimentally would be with Anderson a perhaps with Larson. Or even —
Yes, he was very close with Loritzan(?).
Let me ask another question. Do you recall Bohr’s visit in 1933? visit at Cal Tech, stayed a while, then Berkeley did you have any contact?
Yes, I can remember seeing Bohr down there and hearing him give talks about some of the problems. It was along about that time that he had had this argument with Einstein, in which the box had the shutter that was opened and let out a proton and you weighed the box and so on. He had found the answer to that one. I remember him giving a talk on it, in which he explained it, and he and Rosenfelt had either finished or were well along with their great paper the measurability, and I believe he gave some lectures on that. I have a suspicion though that lectures on that were prepared and given by somebody else around, because I think I got more out of them than I would have if Professor Bohr had given them, because as you know, one often didn’t hear what he said. I seem to have a picture of somebody’s lecturing quite audibly on this but I don’t know what it was.
That’s interesting. So you were at Cal Tech at the time Bohr was there.
Yes, I was right there at the time he visited in 1933.
That was his first meeting with Oppenheimer, as a matter of fact.
It was? I wasn’t really aware of it.
It turned out that it was the high spot of his trip, as he reported it later.
Yes, America wasn’t studded with theoretical physics in those days.
He wasn’t referring so much to that, but I guess to the environment, Milliken’s approach a so forth, the publicity associated with his visit which he didn’t like very much.
Oh, he didn’t like the reactions.
He was put too much into positions which were uncomfortable.
Well, his character — I suppose, two people of more unlike style about public relations than Bohr and Milliken —!
Yes, that really characterizes it. Did you see him at Berkeley as well?
I can’t remember seeing Bohr at Berkeley. I don’t remember seeing Bohr except in Pasadena during that period.
Were there occasions on that trip when he was involved in discussions with you and Oppenheimer and some of the others, or was it strictly on this more formal level?
I don’t think we ever had any real close discussions with Bohr about anything. At least I didn’t. Oppenheimer may have spent considerable time with him. My impressions are a little bit vague. I know Bohr gave a number of lectures that I attended and so on. I don’t think his visit was very long or involved very much actual close work with people.
It was intended to be longer than it worked out. He had this big talk to give in Chicago. You didn’t go to that APS meeting in Chicago, did you? It was at the time of the Century of Progress Exposition, ‘33.
I don’t believe I went.
Cockcroft was there.
I can remember being at one of those meetings at Chicago in the summer, and they probably didn’t have very many, in Chicago in the summer. The usual time in Chicago was November. So I suspect that was it. I can remember being there and going to the Century of Progress with my wife and a few friends and relatives, and I can also remember very definitely seeing Oppenheimer at about the same time, and so that must have been at that meeting. But I don’t remember anything about the meeting. The thing I remember about Oppenheimer in particular is his fantastic way of circumventing a certain traffic situation that arose. I mean, he had his own ways of cutting through traffic. That’s right — not necessarily based on the greatest happiness of the greatest number, or an extreme concern for the rights of all the other drivers! So I must have been involved somehow in attending part of that meeting at Chicago, but it just doesn’t come through to me now about it.
One of the things I’d like to talk about, for which we won’t have time now — I’d like to talk more about some of the other summer schools at Michigan. I’d like to talk more about your own work, Furry theorem for example, the transition to Harvard, how it came about finally, this apparently deferred trip to Harvard.
Well, that came about very simply. I mean, the question was, whether anybody would get a job, and I got a telegram from Harvard offering me a job, while Oppenheimer was away at an Eastern meeting, I guess the New York meeting in 1934, and I telegraphed back right away that I would take the job. Oppenheimer came back and was a little bit miffed with me for having been so fast about it. He said, “You might have gotten a little bit more if you had played coy.” But I didn’t feel at all inclined to play coy. Job — can I have it? Let’s make it as definite as possible, as quick as possible — that was my attitude.
Who was the person you had contact with on the job? Who offered it?
I don’t remember exactly, but it was presumably sent to me by the department chairman, Saunders. That would be the natural thing. I can remember asking Paton, it probably was, at that Washington meeting in 1932, just who Campbell was at Harvard, whether he was the head, and Paton said, “No, he’s not head, but he’s important all right, and don’t you forget it.” I didn’t notice — I didn’t know the Harvard system in those days at all.
Let me just put on the records, as a reminder, so we can pick up some time this transition to Harvard and your reaction to the situation there, will give you a sort of fourth environment to compare — Illinois, Michigan as far as the summer schools went, Cal Tech, Berkeley, as much as you knew Cal Tech which wasn’t very much, and then Harvard itself. I’d like to talk about the situation there. And then the kinds of things that we mentioned quite casually before, documenting the 1937 Washington Conference on Theoretical Physics since we have some documentation, we might be able to use that as a takeoff point to reconstruct some of the circumstances. And then, as we have time, to take it on up to the later years. So if you’re agreeable, without setting a time at the moment, we could stop now.
To fill up the rest of the tape, I’ll explain that Professor Furry was in Copenhagen at the Bohr Institute on a one semester sabbatical of which he spent I think about three months here. We became acquainted and I determined that it was a good opportunity for an interview. The biographical information I had was from the microfilm of the Sources for History of Quantum Physics, which listed biographical information in a sketchy form for some of the people I’m interested in, although he was not interviewed. At a later date I will continue the interview, perhaps in Cambridge. It’s interesting that up until three years ago he was chairman of the physics department at Harvard. That’s all.