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Oral History Transcript — Dr. Frank Oppenheimer

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Interview with Dr. Frank Oppenheimer
By Charles Weiner
In Sausalito, California
February 9, 1973

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Frank Oppenheimer; February 9, 1973

ABSTRACT: Childhood, early schooling, early trips, to New Mexico and Europe, and influences — parents —, brother and physics teacher; impressions, contacts with scientists, and experiences at various, schools and laboratories — Johns Hopkins, Cavendish, Florence, Stanford, Berkeley, Minnesota, and Colorado political involvements and subsequent blacklisting; ranch years (1949,1959); return to scientific career; and current involvement in science museums. Scattered throughout are discussions — on brother, J. Robert, influences, development, reactions to events, and changes.

Transcript

Session I | Session II

Weiner:

I suggest we start from the beginning, or as far back as you can. I know you were born in New York City in 1912. I'd like to talk a little bit about the environment, about your family background and your home life. For example, where in New York City? Manhattan?

Oppenheimer:

Yes, 88th Street and Riverside Drive, on the Drive. With a great view of the river and the city until gradually other buildings came up around us so we didn't see the city so much anymore.

Weiner:

How long did you live in the same place?

Oppenheimer:

Until I went to college; on the 11th floor in a red brick building.

Weiner:

How many were there in the family?

Oppenheimer:

My brother and I and our parents; my mother's mother lived with us for quite a while.

Weiner:

You remember, she had been living with you.

Oppenheimer:

Yes.

Weiner:

About how old were you when she died?

Oppenheimer:

I must have been about 13 to 15, somewhere in there, I think.

Weiner:

You went to Ethical Culture School later. Were there other schools nearby, public schools?

Oppenheimer:

I went to kindergarten in a small school and then started in the Ethical Culture School in the 1st grade. Then just as I got through the 7th grade, they had the new high school at Fieldston built and I finished high school up there.

Weiner:

That's in Riverdale, isn't it?

Oppenheimer:

Yes. Just sort of at the edge of Riverdale. It's the high school that is run by the Ethical Culture Society. At first all the schools were together in the one building on W. 64th Street.

Weiner:

Before we get to school, looking back at the family background, I know your mother was a painter but I'm not sure whether that was a hobby or profession. What does one really mean when one says painter?

Oppenheimer:

She went to art school and then went to Paris for a year and a half or so and studied and painted there, came back, had a studio in New York, which I gather was a very nice studio with fishnet strung all around it and northern lights and all the right things. She taught art at Columbia or Barnard. I guess that's when my father met her. After she was married, she didn't do very much painting. Every once in a while, over the years, she would set up an easel and do a still life or a landscape. But the artistic growth of my parents was interesting, because they had very conventional sort of dark paintings for a long time, and then got interested in other things. And I think one of the first larger paintings they bought was a dark, romantic thing by a man called Panini, with all kinds of Roman columns. Then a Jonas Lee landscape. Then they gradually got interested in Impressionist painting, and collected a really very nice little collection, and got to know some of the more contemporary painters who were coming to New York, people like Max Weber and some of the art dealers like J. B. Newmann. So that there was over a period — really after the war but primarily from 1920 to 1930 — a genuine growth in their art interest. And our home was full of nice paintings as well as people who were selling and making them.

Weiner:

What was her background? Was she from Europe?

Oppenheimer:

No, she was born in the U.S. I think her grandfather had come from Germany. Her mother took her as a child to live in Germany for a while.

Weiner:

And your father?

Oppenheimer:

He was born in Hannau, Bavaria in Germany and came over when he was 18, and had somewhat distant relatives in a little company called Rothfeldt-Stern, and worked there; gradually took over the management of the business. It was a very specialized business. It imported and wholesaled the linings for men's suits. My father was always very proud of his color memory. We'd ask him to match a color, get the right color for a suit or yarn, and he'd find just the right thing. He imported quite a few lining cloths from England, alpaca linings, had contacts there and would go there; and I think did rather well during the war in that his company provided quite a few of the linings for the Army jackets.

Weiner:

This traveling he did once in a while, did it ever involve you as a child?

Oppenheimer:

Well, the traveling — I don't think he made many independent trips. Before the war, I think I probably made one or two trips with my brother, and then again a trip in 1921 and in 1924, in which he spent some time on business, but most of it on vacation.

Weiner:

Did you go on those?

Oppenheimer:

Yes, the whole family went.

Weiner:

He [Robert] stayed in Europe, '25, '26?

Oppenheimer:

No, after the 1921 trip he got very sick, and came home, and then went to Harvard and then went back to Europe after Harvard.

Weiner:

Some kind of a trench dysentery or something, wasn't that part of it?

Oppenheimer:

Well, he went to the Hartz Mountains to collect minerals. I think this was shortly after the war and there was probably a very prevalent dysentery all through the restaurants and everything. I don't think it had anything particularly to do with caves.

Weiner:

Getting back to the New York environment, as I'm picturing the apartment on Riverside Drive, it was filled with artistic things, paintings. You mentioned some of the people who came in. How about books? What kind of reading materials, what kind of general atmosphere?

Oppenheimer:

They had lots of books. I remember periods, very vaguely, in which my father especially would get hold of some history book and get fascinated by it and start telling everybody about it. I don't remember the history of what. I don't remember my mother talking about books. I think she read. It wasn't really a bookish family in any way but it was a literate family. My grandmother used to go down and listen to a regular annual lecture series with Steven Leacock, for example, because at that time when there was no radio, the very fashionable thing was to listen — they had traveling lecturers at Town Hall. Every time there was one, which may have been once a week, for all I know, she would go listen to the lecture series.

Weiner:

This was your mother's mother.

Oppenheimer:

Yes.

Weiner:

She was from Germany but spoke English?

Oppenheimer:

No, she was not from Germany. It must have been my mother's grandparents that came from there.

Weiner:

In the home what was the general atmosphere? Quiet? Noisy? Were there other kids, playmates, relatives visiting, anything like that?

Oppenheimer:

There was quite a lot of company and fairly formal dinners. I don't remember anything much that happened before 1922. But there were people. There were dinner parties. They went out. Very often they went to concerts, or to the theater. During the summer, we had a place in Bay Shore, Long Island, and there were always people coming to stay with us there or visiting, and occasionally, as on my father's 50th birthday, a great crowd of people. The family had a feeling of friendliness and warmth and gentleness, and quite a lot of conversation, I guess, about various things, but also it was reasonably formal. Both my brother and I had nurses. Everything was done in the home. In one sense, Father, I guess, had lived in the generation just after the one that discovered germs, and so germs were really a deadly enemy, and one couldn't buy apples off the street because the vendors would spit on them and contaminate them, and the barber came to the house and cut one's hair, and I had my tonsils out in my own room. Just a general distrust of the pollution of the outside world. My father would often reminisce about changes in New York, see a block and remember that there had been a pasture with goats in it not too many years earlier.

Weiner:

What about music lessons or other kinds of instruction? Did you have that?

Oppenheimer:

I had some piano lessons, I suppose. They didn't last very long. When I was about 14, I had [gone to] — one of Walter Damrosch's concerts where he would isolate the instruments that carried the melody and explain what was going on. I heard a flute and really fell in love with it. In general, with both my brother and me, if we had some enthusiasm my parents would cater to it. I know they did very much with, for example, his mineral collection. They made all kinds of things possible. I didn't read very much but I got very interested in Chaucer in high school, so they bought me a 1721 edition of Chaucer. And when I got interested in the flute, they were away in Europe right after that and brought me back a wooden flageolet. I was sick when they came back and I learned to play that, and wanted to go on to the flute and they found a flute teacher, and the flute teacher they found was George Baibire. He was really one of the greatest flutists in the country. They went and consulted with him and found out what kind of a flute to buy, and I had two or three marvelous years of lessons with him. Once I asked him to come to the house and play for my parents' anniversary, to play for them. He couldn't put on a concert because of his agent and what not, but he agreed to come and give me a lesson in the house, but the whole lesson was [a concert] — and my parents sat there very formally, and he said he felt he was playing for a little royal family.

Weiner:

How long did that go on?

Oppenheimer:

For about three years. Then I went away, but whenever I happened to be in the same town with him I'd go for a lesson. If he came to give a concert in Los Angeles or Baltimore.

Weiner:

So you kept on. What about hobbies. You mentioned your brother had minerals — his preoccupation, I gather. What about yours?

Oppenheimer:

Well, my earlier hobbies were pretty much gadgetry. I was very good at, when I was very young I think, taking apart bicycles and putting them together. I used to wander around New York City and there was a street called Centre Street, which had nothing but second-hand electric motors on it, and I'd get the electric motors. I would use the DC that we had in our apartment for welding and would often practically not be able to see for days. I didn't know enough, not to worry about the ultraviolet. So this kind of gadgetry and wiring and playing with motors and making things was a hobby. My brother kept giving me little things. He left me a microscope when he went to college. And once he saw a gadget in a store when he was in Harvard and sent it to me without knowing what it was, and it turned out to be a slide microtome, and I had a good time slicing everything and looking at it under the microscope. In fact it was quite nice, using a microscope to look at all kinds of organic and inorganic things and getting fantasies about them.

Weiner:

In an artistic sense?

Oppenheimer:

No, just in the sense of how they were made and what they were made of. I remember the first time I looked at my own sperm, and never having heard of sperm, it was really quite a marvelous discovery.

Weiner:

That's really an interesting sequence of events. How did this interest start? You don't just one day go down and buy an electric motor or piece of it. Can you think how this interest first began to manifest itself? Anything you read or talked about with your brother or others?

Oppenheimer:

I got interested in automobiles. One year I suppose, when I was 8 or 7 or something like that, I had a tutor out in the country, and he had a great big thick book on automobiles. I remember one very nice thing; I've often quoted to people, and my learning about the differential in a car. I'd often seen a car jacked up and realized that if you turned one wheel one way — one of the back wheels one way — the other one would go backward, and I knew that the differential was to help you go around corners, and it just took so long to relate these two. Then suddenly I was able to make at some point, this transformation, and realize that backwards in the rest frame was slower in the moving frame, and it was the most wonderful bit of insight for me. So I guess probably partly through the bicycles, through the automobiles, I got interested in mechanical things. I'm not sure really. Watches — watches were great, taking them apart and putting them together.

Weiner:

You had good facilities to do it?

Oppenheimer:

Yes.

Weiner:

Did you have any tools, sets of tools?

Oppenheimer:

I'm sure I did. I never liked them very much. I liked separate tools. I didn't like little combination tools.

Weiner:

How about other things like chemistry sets, did you get involved in anything like that?

Oppenheimer:

I had a chemistry set, but never did anything that I wasn't ashamed of. I never followed the little book and never did anything very systematic or understood anything very well. I don't mean ashamed of, but I never got much satisfaction out of the chemistry set.

Weiner:

Did you do any of this with your brother? There was an age difference —

Oppenheimer:

There was an eight year age difference. I didn't do very much of this — but as I got into high school, he would write me quite often. I would write him about what I was studying, and he would write me little tidbits which would egg me on.

Weiner:

You were in high school when he was in college.

Oppenheimer:

He was in Europe or teaching in Pasadena.

Weiner:

Did you get involved in any of his mineral collecting or classification?

Oppenheimer:

No, not really. I had a little sort of spinoff collection of his, but I didn't really get involved in collecting on my own.

Weiner:

Did he get involved in your tinkering with motors?

Oppenheimer:

No.

Weiner:

Did you have any friends that you did it with?

Oppenheimer:

Occasionally. Most of it was solitary. I had a black friend with whom I took the player piano apart and put it together with one night.

Weiner:

Not at home?

Oppenheimer:

Yes, it was at home.

Weiner:

Oh, you had a player piano at home.

Oppenheimer:

Yes. Yes, my father used to play the player piano, with a most effortful expression. He would put everything into it that a finger pianist would do. For himself — I don't think the whole family ever sat around but maybe I did or somebody.

Weiner:

There are very few mechanical toys of that stature in houses anymore.

Oppenheimer:

Yes, I know.

Weiner:

Unless you consider a washing machine. During this time, with the motors and so on, you were going through your high school years.

Oppenheimer:

Yes, early high school.

Weiner:

What kind of student were you as early as you can remember?

Oppenheimer:

I don't remember a damn thing about elementary school, except that almost every summer I had some sort of a subject to make up. The whole business of the vacuity of elementary school puzzles me. I remember things that happened in my life when I was that age, some of them, but I can't remember what I was taught or what I was good at, except a general feeling of not being very good at almost all of it, like arithmetic, writing, and spelling.

Weiner:

Things you made up were things you hadn't been interested in completing?

Oppenheimer:

I don't know, but in elementary school they would give conditions before you could go on to the next grade, and my recollection is that I always had at least one, maybe several conditions, which I was supposed to make up during the summer. I don't remember what I did about it.

Weiner:

Maybe that's where the tutor came in?

Oppenheimer:

The tutor was really later than that. The tutor was in 1920. I must have been eight. Yes, it could have been.

Weiner:

Do you recall anxiety about the schoolwork? Was it a big problem for you?

Oppenheimer:

No.

Weiner:

I mean a problem that you had to make up things.

Oppenheimer:

I don't think so, no. I don't remember much about it. The whole thing was a blank. I find other people for whom elementary school is the same sort of blank, and I wonder very much what it means in terms of the kind of teaching that goes on, because this was an enlightened school, probably as enlightened as they come at that time. The classes weren't too big and the teachers were dedicated.

Weiner:

Well, I can imagine not remembering anything as to content but remembering the external circumstances.

Oppenheimer:

I remember the building. I remember that the 4th grade had a narrow rectangular room. In fact, I went back there about two years ago. A lot of it was extraordinarily familiar. Everything was a little smaller than I remembered.

Weiner:

How about friends? You mentioned your hobbies, (sometimes a misleading word, hobby) — these interests of yours were pursued pretty much by yourself. Did you engage in much play, sports, athletics, community things, horsing around with other kids?

Oppenheimer:

I had friends. I can't remember any — I had one friend who lived in the apartment that I'd see quite often, a child of my parents' friend, and then in the 7th grade I knew quite a few people. We'd take the trolley car together, go to each other's houses, go out and go to shows and various things together.

Weiner:

Was the age gap too much for you and your brother to do things together?

Oppenheimer:

It was — until about the time he went to college. I don't remember exactly when. But when he got the sailboat, we spent an enormous amount of time sailing together, and I remember even earlier than that, going out of New York and taking a walk out and breaking into a fire lookout tower, and leaving 50 cents for the guy to get a new lock. We'd go hunting garnets together occasionally up at Spuyten Duyvil. Then when we went to Europe in 1921, he and I spent many days — we'd take the train from Cologne to Godesberg and wander around the Seben Gebirge together and really got to know each other pretty well. It was an interesting time, because an army, especially the French army, of occupation, was still in the Rhineland, and it just stuck with me, what a horrible thing it is to have an army of occupation. It was so awful with the natives. I was nine.

Weiner:

Interesting — you weren't either nationality —

Oppenheimer:

Even then as a nine year old, it was clear what crudeness was there.

Weiner:

Did you know any of the languages — ever speak German at home?

Oppenheimer:

I spoke it a little bit, never as well as my brother, and never spent as much time in Germany as he.

Weiner:

I meant at that time when you went over, '21, you spoke it a little bit?

Oppenheimer:

Yes.

Weiner:

Where else did you go on that trip? You told about the excursions with your brother. He was 17?

Oppenheimer:

He was 17, yes. This was the first trip we took to Europe. Then we went to Godesberg, the whole family, and then he took off for the Harz Mountains and I got sick in Godesberg and didn't do very much more, and he came back with his mineral collection and dysentery. So I guess that's all we did. We spent a little time in England, but not much. Then we went back in 1924, and spent quite a lot of time in England, and then took an airplane from London to Cologne. Then again, my brother was with us for a while, while we traveled around Germany and Munich, then left and joined us again while we were vacationing in the upper Engadine. Then again he and I wandered around a lot together. He was an enormous influence on me, I think, in all ways. When you say, what got me interested in something, apart from this mechanical thing — he had toys he gave me, gadgets really, that he gave me.

Weiner:

The older brother giving you guidance, talking with you — were you aware of his own development, concerns, interests?

Oppenheimer:

I think so. I'll show you some of the correspondence that we had while I was in high school. I know that when I graduated from high school I had some idea that instead of going to college, I would go and study with him, and he very wisely felt that wasn't a good idea.

Weiner:

That was a little early for him, to take students. It's hard to pin down a specific beginning of an interest in science. It seems to have developed as part of the natural pattern from early —

Oppenheimer:

I think so, from the mechanical and electrical interests, some of this. I'm sure that the physics course that this Mr. Klock taught had a big impact. I remember being terribly intrigued by the way vague notions were made precise. A case in point which I remember from the physics course is the notion of pressure. That pressure, which is such an intuitive thing, [is] then defined as a force per unit area; and that out of this definition, one could see all kinds of consequences. Without that you couldn't understand a hydraulic jack, but with this definition of pressure, a hydraulic jack made a lot of sense. It was very nice. And it happened with other things, with acceleration.

Weiner:

By this time was he at the Fieldston School?

Oppenheimer:

Yes, he was at the Fieldston School.

Weiner:

So when your brother had him he was also at the high school, but when it was located in Manhattan.

Oppenheimer:

That's right. And that year, the first year we moved into the new high school, probably was the same year as the physics course — my parents went away and I lived with my French teacher right next to the school. I learned a lot of French but also had a lot of time on my hands, and they were just setting up the laboratory. I remember they had a big switchboard and so on — [it] could distribute various voltages. They had batteries and a little motor generator, and [one could] plug them in and get them distributed. I made great charts, spending a lot of time planning the most efficient use of the switchboard. Also, the tutor I had, had been a medical student, and I'd gotten very fond of him. But he died of blood poisoning while I was in 6th or 7th grade or something. And so, I don't know quite how it got started, but when we went to Fieldston I had responsibility of setting up a little science library, in connection with — well, in his honor, called the Michaelis Library. It's grown and still exists at the school. I remember Mr. Klock insisting that I order, and reading a series of books called "Ostwald's Klassiker." They were really quite great.

Weiner:

In German. You could practice what you knew as well as getting a great deal of the history of science.

Oppenheimer:

Yes.

Weiner:

I'd like to know a little more about Augustus Klock who was the teacher your brother talked about as being quite influential. I know very little about him — what kind of a person, what background, how far had he gone in science?

Oppenheimer:

Not terribly far. He knew the elementary physics really well and taught it clearly and with obviously some sense of excitement, with the niceties of the subject. He also taught chemistry there, but not as inspiringly, at least I wasn't as inspired by it, although it was always very neat and things worked out well. We did have a lot of laboratory work. If one wanted to do extra things like the project with the switchboard, he encouraged one and praised one.

Weiner:

Did he find certain texts that you remember?

Oppenheimer:

I don't remember what the texts were. He did use the students in his class to tutor other students in his class. I remember doing some of that.

Weiner:

You did some of that because by this time you were doing pretty well.

Oppenheimer:

I guess so.

Weiner:

And he knew your brother — was that any influence, when you come to school with the same teacher, plus or minus?

Oppenheimer:

Yes, but I think he was probably quite disciplined about it, though, because I didn't notice any feeling of having to live up to my brother.

Weiner:

Your brother's interest at that time developed in chemistry, as a result of the minerals, I guess, and the teaching. He stressed that part of it. But yours was more the traditional physics.

Oppenheimer:

Yes. And the course was good enough so that when I went to Hopkins, I was able to talk my way out of taking the general physics course at Hopkins.

Weiner:

You were perhaps 12 when you went to Fieldston?

Oppenheimer:

The high school was just built when I was going into the 8th grade. So I entered it then, which would have been, what?

Weiner:

You'd have been 13 so it must have been —

Oppenheimer:

I must have been 14, something like that, isn't that right? No, five years I graduated probably when I was 17, so I must have been 12 or 13.

Weiner:

So it would have been, let's say, 1925.

Oppenheimer:

Yes.

Weiner:

That's what I was going to get to about the physics. Was there any attempt to talk about current or recent developments in physics, though you were just getting the introductory course? I mean, for example, quantum mechanics was developing very rapidly.

Oppenheimer:

Well, yes. I don't remember whether it was in the course or in connection with the little library, but I remember reading a lot about the Bohr atom.

Weiner:

You don't remember a particular book that would fix that.

Oppenheimer:

No, I don't remember. Another book that my brother gave me, I think he gave me or recommended, was the Galileo, the TWO NEW SCIENCES, and I remember reading that and not really understanding it. It was quite a while before I had taken physics. I'm sure I was influenced by it.

Weiner:

What about mathematics in high school? Do you recall how much you had, what courses?

Oppenheimer:

There was no calculus. There was algebra and plane geometry; I think a year of each, then a course with solid geometry and trigonometry — half a year of each. A rather good teacher, I think, so that I enjoyed the subject.

Weiner:

You had math, had chemistry, and had enough physics or did well enough in it so you could go beyond those courses. Do you think this was due to your special abilities and interest in it, or was it the level of teaching at the Ethical Culture School, which was a rather good private advanced school? I just want to see how different you might have been than the other people who came through the same physics course.

Oppenheimer:

I don't know. I never thought of myself as a good student, and yet when I went to Hopkins I did very well and it was relatively easy for me. So I think the school must have been a better than average school.

Weiner:

It seems to me, we established while you were in high school and your brother first in Harvard, 1922-25, —

Oppenheimer:

— and during that time we spent the summers pretty much together, in Bay Shore.

Weiner:

What were you getting from him or observing in him during that period, observing any changes in his interests?

Oppenheimer:

During the time he was at Harvard he was a great devotee of Percy Bridgman, and would tell me a lot about him as a man, and also the work he was doing. The high pressure work. He named his sailboat, which we used a lot, after trimethylamine, which had interesting properties. I've forgotten what intrigued him about it, so the boat's nickname was the Trimethy but its full name was Trimethylamine, and he came back bubbling over with that particular compound. He had friends who would visit him at Bay Shore, people like Paul Horgan — Francis Ferguson.

Weiner:

Francis Ferguson stayed a close friend.

Oppenheimer:

Yes, and Paul Horgan would have but he died.

Weiner:

I don't know much about Horgan.

Oppenheimer:

Paul Horgan was an author, and also a poet.

Weiner:

He was a friend from that period.

Oppenheimer:

Yes.

Weiner:

They were around.

Oppenheimer:

Yes. I saw them some. I don't remember any very enlightened conversations. I'm sure there were lots.

Weiner:

So when he came back, Bridgman was the high point, as well as Bridgman's philosophy. Were there discussions of what Bridgman was into?

Oppenheimer:

I think so, yes.

Weiner:

When he went off then to Gottingen, as I understand it, his idea was not so much theoretical physics necessarily as opposed to experimental — he saw it as all of a piece. Do you remember any discussions he had regarding the decision to go?

Oppenheimer:

No. He first went to Cambridge, and it was there that he decided that he was not an experimental physicist.

Weiner:

I guess he was at the Cavendish. We'll get back to that later. When did you decide that it wasn't your brother whom you wanted to study with but that you were going to study something in particular, and then the particular place?

Oppenheimer:

Well, I suppose because of his influence, I first thought I'd go to Harvard, and took all the College Boards for Harvard, and did all right on everything except English which I was supposed to take over again. Then I had a friend that I had known, we'd gone to New Mexico together for a couple of summers and he was going to Hopkins and, had gone down to visit it, and he told me about it. And it sounded to me better than going to Harvard, for a variety of reasons. So I decided to go there. I don't even remember applying to go there but I must have.

Weiner:

What did you have in mind to study?

Oppenheimer:

I think physics, because the first year I was there, I took calculus, and there was the sophomore course on theoretical mechanics, and a very good chemistry course. I didn't take biology till I think the second year, and it wasn't a very good course. My brother kept telling me about the wonders of biology but I didn't discover them in that course. It really was a very dull and traditional course.

Weiner:

Was it an elective? Was it normal for a physics major to take a biology course?

Oppenheimer:

I don't know what was normal at Hopkins. It was an extraordinarily nice school. You could do pretty much what you wanted. So I'm sure I took it because I wanted to. There were good courses in both the inorganic and organic chemistry course that I took, and some good history courses, and I took quite a lot of French literature, and George Boas was there in philosophy. It was a marvelous group of people — Joe and Marie Goeppert-Mayer were there. In the physics department there was Dieke, whom I saw a lot of, and Pfund, who was into all kinds of simple optical things, and Wood, who was really my hero. I remember doing something which I can't imagine a student doing now — sort of hiding in the hallway looking in, watching him work, and if Wood looked up I would move out of the way so that he wouldn't see me. He was a beautiful craftsman.

Weiner:

Did you have any courses with Wood.

Oppenheimer:

Yes, in physical optics, was one of them. They were kind of relaxed courses in which he would bring in little gadgets and stuff. I remember one thing, in one of these courses, that I feel like writing Houtermans about now, and that is that one day somebody came in and reported some experiment and we talked about some effect, I don't know, Jones effect, and he said, "I'm glad windows were invented before the modern day or you couldn't look out the window without saying, observe the 'Matthews effect'." I find this is true now. I'm out of the field for a little bit and I read the PHYSICAL REVIEW Letters. They don't ever describe what's going on, they always name what's going on by somebody, and it makes them absolutely unintelligible. The Letters are really the best place to keep up with physics except for that defect.

Weiner:

For example, the Josephson effect, the Lomb shift, the — Gunn effect?

Oppenheimer:

Yes, and in solid state it's just impossible. And it would be quite easy, it wouldn't take up much more room in the Letters to describe the effect rather than name it.

Weiner:

Part of the general thing of making everything as cryptic as possible.

Oppenheimer:

Yes. And this was one of Wood's gripes. But Herzfeld was there, and the mathematicians were Murnaghan and Wyburn, in M theory and Wintner in analysis. I think Wheeler was there as a graduate student, and I know also Ken Bainbridge, whom I met again in Cambridge, England.

Weiner:

Yes, he was. How about Gregory Breit, was he there at that time or had he already gone?

Oppenheimer:

I didn't know him anyway so I think he may have already left.

Weiner:

I think he was on the faculty, and Merle Tuve had come through there, probably gone by '25, that's right.

Oppenheimer:

I was there from '30 to '33.

Weiner:

Tuve was in Washington then. Well, let's talk a little bit more about Wood. I'm curious about him. We hear lots of anecdotes about him now, his style. How was he in the lectures? Was he good at the demonstrations he set up? Did they work?

Oppenheimer:

Yes, they always worked, and when he wanted to show the anomalous absorption of sodium vapor it was very clear. His lectures weren't always, because he would digress a great deal. I remember one time somebody had given him a toy. It was just a little vibrating magnet under a man on a string and the man would dance, sort of randomly, and we spent a lot of time in class watching that.

Weiner:

Let's talk about the laboratory facilities there. You didn't explain why you preferred it to Harvard. Was one of the reasons the laboratory setup?

Oppenheimer:

No, I don't think so. I think it was partly the staff and partly the kind of freedom to pick one's own curriculum that it had, and the spirit of the place. It had — I've forgotten what year, but not too many years before, been solely a graduate school, so that it was just the opposite of a junior college, which often is a continuation of high school. Hopkins had filtered to the undergraduate level from the top down, and it made a great deal of difference in the way they regarded what was required to get an education. And I was able to work fast there. I think I got — one needed 125 units to graduate, and I think I got 110 of them in the first two years, so —

Weiner:

Does that mean that you overloaded with courses?

Oppenheimer:

I took a lot of courses. I got credit for some courses and so on.

Weiner:

That you knew before — does that mean you had to take exams?

Oppenheimer:

I think in some cases it was an exam, in some cases just an interview.

Weiner:

How about the laboratories? They were so well known for their optics, the great spectroscopy setup, in Rowland's day.

Oppenheimer:

Yes. The third year I was there I did some pseudo-research with that, at least took some pictures and measured some spectral lines, yes.

Weiner:

Was this part of an undergraduate thesis?

Oppenheimer:

No. One did have to write an undergraduate thesis but I wrote it on some other topic. Now, this was just because I wanted to do it.

Weiner:

What was your topic?

Oppenheimer:

It was on continuity, talking about the — some of the Greek motion paradoxes and what an enormous difference it had made to enable one to think about motion by going to the limit. The thesis discussed the idea of limits in general.

Weiner:

That sounds mathematical-philosophical rather than —

Oppenheimer:

I think it was. I still have a copy of that.

Weiner:

Was there someone who was your principal advisor, someone with whom you had the major relationship on the faculty?

Oppenheimer:

The two people I saw most of were Dieke as a physicist — and we'd take lots of walks together and belonged to a Bach club together and went up to Bach festivals together — and the mathematician Wintner, who always stayed up late and didn't mind if I came by at 1 o'clock in the morning. He was a great teacher, really. I took a course on complex variables from him.

Weiner:

How about Dieke? He had been in California for a couple of years —

Oppenheimer:

And in Japan.

Weiner:

He had been in Japan — and had come from a European school, Leyden — I know that he was in close touch with European science. Did he introduce any of the new ideas in physics?

Oppenheimer:

You mean, the Dirac? It was before Dirac.

Weiner:

After one part of Dirac, but by this time, quantum mechanics which had been developed in the preceding four or five years — did anyone really teach that?

Oppenheimer:

Yes.

Weiner:

Who, Dieke?

Oppenheimer:

Dieke, in its connection with spectroscopy. He was almost wholly a spectroscopist.

Weiner:

Did anyone do it as theory, a course on the theoretical aspects of quantum mechanics?

Oppenheimer:

Let's see —

Weiner:

It wouldn't be Wood or Pfund — Dieke's a possibility — or maybe among mathematicians?

Oppenheimer:

No. Murnaghan taught essentially Whittaker and Watson.

Weiner:

That was the basic book.

Oppenheimer:

But nobody taught any sort of axiomatic quantum mechanics, we would do things like — derive a Schroedinger equation by putting together -sort of treating it more or less the way Jost does in his book. Seeing how out of a wave equation and a least action principle, one could get a Schroedinger equation.

Weiner:

Did that give you enough of it?

Oppenheimer:

No, I don't think it did, really.

Weiner:

At that stage you didn't really learn quantum mechanics.

Oppenheimer:

No. Not at all, till I got to Cal Tech.

Weiner:

Not in your undergraduate years; because of the quality of the faculty you mention, I keep forgetting — How much of your work was lab work?

Oppenheimer:

Let's see, there was a lot of optics lab. I don't think, I don't remember taking electricity lab. I didn't take the introductory course. There was a lot of chemistry lab and biology lab, and there was one other physics lab. So there was a lot of lab work but it was not all — I think chemistry probably took up more lab time than physics, or the optics lab, Pfund's course in optics was essentially a lab course entirely.

Weiner:

In chemistry you mentioned Joe and Maria Mayer. [Goeppert-Mayer] Did you have any contacts with them?

Oppenheimer:

Socially. I never had them as teachers.

Weiner:

They were not on student status there.

Oppenheimer:

No. I guess just through the faculty in physics that I knew, I saw a lot of them. I don't remember whether it was at dinners or on walks or what.

Weiner:

It was still a small group so you could have contacts with all these people.

Oppenheimer:

Yes.

Weiner:

Did you live in a dorm?

Oppenheimer:

No, I lived off the campus.

Weiner:

What about visiting lecturers or special discussion groups? Well, there were seminars, and I wasn't savvy enough to know who was important and who wasn't of the visiting lecturers who came to the seminars. But a lot of them were just graduate students and faculty giving talks. They were essentially graduate seminars but there was no difficulty for an undergraduate to sit in on them.

Weiner:

Was there general —

Oppenheimer:

— I don't think I ever gave a paper, but I sat in on — the seminars which were sort of mixed talks and/or journal clubs; they happened once a week.

Weiner:

During this period, through 1933, there are a few new things happening in physics which now we see as pretty important. I wonder if you recall any of those. For example, was Urey there when you were there? He was in Columbia at the time, went there about 1930 I guess, to Columbia —

Oppenheimer:

— might have been there the first year.

Weiner:

In the beginning of '32, there was the deuterium discovery, and then you had the neutron —

Oppenheimer:

The neutron was just at the end of my time. Let's see, that was…

Weiner:

— February of '32. Then the Cockcroft Walton disintegrations were — April, May —

Oppenheimer:

I was very aware of them but I don't remember how I got to be aware.

Weiner:

We're trying to find out how people hear about those things. Did those developments which indicated a drastic change in nuclear physics influence your interests at all? Had you by this time started to get interested in one branch more than another?

Oppenheimer:

Not then, I don't think. I think it was my brother that suggested I go to the Cavendish, but it seemed reasonable to me to go there. Probably because of the influences around me of the faculty at Hopkins and my brother, and the people who'd come to visit us, — we'd be spending the summers in the mountains then and Uhlenbeck and others would be there — I don't really remember making any decisions.

Weiner:

It just seemed the natural thing to do.

Oppenheimer:

Yes.

Weiner:

All right, to introduce something new — your summers in the mountains. The first we heard about the West was when you said you went off to New Mexico with a friend, earlier, high school days. How did that come about? Was the New Mexico thing to visit some place your friend was going to, or did you go to a family settlement there?

Oppenheimer:

Well, I guess when my brother was sick; he had wandered around the West, Colorado and New Mexico, with the English teacher from the high school, Herbert Smith, and in the course of that time had gone to the Pecos Mountains above Santa Fe. During the summer of '28, I went to a boys' camp in Colorado, and then met my brother in the fall of that year in the Pecos and we went and looked at this place. And then that winter, we arranged to get a lease on it. I went back in early summer of 1929 with my friend Roger and another friend and started setting things up. And then my brother joined me, and we went there every summer from then on, essentially, until I went away to England.

Weiner:

The summer camp experience which would have been 1928 — was it a dude ranch kind of camp? You were a camper?

Oppenheimer:

No, it was a traditional boys' camp. I'd been sent to a boys' camp in Maine for a couple of summers, as had my brother for one summer, and was thoroughly miserable with it. (off tape)

Weiner:

You mentioned you'd gone unsuccessfully to these summer camps in Maine.

Oppenheimer:

Yes, several years before. This, as far as the boys' camp goes, wasn't much more successful, but we did a lot of riding around the beautiful country in Southwestern Colorado and got in the truck and toured around the Navajo country — dug up old Indian ruins. It was a very eventful sort of thing. I enjoyed the scenery and the horses. Let's see, I think it must have been at the end of that year — that my brother and I met in the Pecos in the fall, then went up to Colorado Springs. My brother and I both learned to drive, and after taking lessons for a week we then started off to Pasadena. We had a variety of mishaps, but finally got there.

Weiner:

You mean, with the car.

Oppenheimer:

Yes. He wasn't established in Pasadena — I think he visited there and then went up to Berkeley. I'd have to look up the chronology.

Weiner:

'29 is when he took the position there. He got back from Zurich and Leyden in '29, then went to —

Oppenheimer:

Yes, but I think he'd been in America the summer of '28, late summer, went to Pasadena and talked to people —

Weiner:

Yes, he was a National Research Fellow at Harvard and Cal Tech, ‘27, ‘28.

Oppenheimer:

OK.

Weiner:

So that's when you went with him —

Oppenheimer:

— and dropped him there, then went back East.

Weiner:

With the car?

Oppenheimer:

No, left the car with him.

Weiner:

That was the beginning of the —

Oppenheimer:

— of the ranch years, yes.

Weiner:

This didn't involve the parents, just the two brothers.

Oppenheimer:

Yes. Well, they leased the place, I mean Father did.

Weiner:

But it wasn't for the family, it was for the boys. You mentioned then about people visiting. When did it start that this became a place for others to visit and became a kind of tradition? You mentioned Uhlenbeck for one.

Oppenheimer:

I suspect that the Uhlenbecks' visit occurred either the first or second summer, then they made repeated visits. Serbers spent quite a lot of time there. I remember Charlie Lauritsen coming there. When my brother moved to Berkeley, many of his friends from there came. And sometimes they would write a paper together, Bob Sapher and my brother especially.

Weiner:

Did you join in much? I'm talking now before you went to the Cavendish, the first years — do you remember any physics discussions? Did you learn anything of physics at the ranch?

Oppenheimer:

Well, my brother always told me what it was all about. But I don't think I really understood it.

Weiner:

Robert was dealing with new research, new developments, mostly theoretical.

Oppenheimer:

Yes. I must have known — I can't remember. You know, you hear these stories, and can't remember how much of it was vague, how much of it was clear, but I remember feeling uneasy on things I didn't know about.

Weiner:

This had started before the Cavendish decision. How did you go about doing it? First of all you were going on your own, no fellowship involved.

Oppenheimer:

Yes. I think my brother wrote R. H. Fowler and said that I'd show up. Then when I got there, I had to arrange to join the college and stuff like that.

Weiner:

Fowler wouldn't really admit you to the Cavendish — the idea was that he would set it up?

Oppenheimer:

I guess so. It was set up. I remember arriving in Cambridge and renting a bicycle, and staying out a little longer than I had intended, so that a cop arrested me for not having a light on my bicycle. The next day I went to the Cavendish and I happened to see Chadwick in the door, and he must have recognized me because he said, "The police are looking for you."

Weiner:

That was your introduction to the Cavendish, what a way to begin. Your brother felt that it would be good for you to follow his experiences.

Oppenheimer:

Yes. But I was quite definitely, by tradition, much more hand-oriented than he was.

Weiner:

Did you have in mind to get a degree there, or was it a question of doing some time to get experience?

Oppenheimer:

I think, to start with, it was open, whether I would enroll or not. In order to get a degree there I would have had to pass the tripos and I'm not sure I could have passed.

Weiner:

You could have been admitted as a research student.

Oppenheimer:

I was admitted as a research student but I did not discuss a degree. I didn't ever explore it. But the procedure there was quite interesting. The first thing — they suggested that I look around and talk to a lot of people, and then at the same time, they initiated me into the laboratory. And they initiated you into the laboratory, in an attic with a piece of glass apparatus in it, which had no function whatsoever, except it had a diffusion pump on one end and maybe an ion source on the other, I've forgotten exactly. The object was to get it all put together again. It was soft glass. They had only a torch with gas and air — no tank gas — and the way you got the air was, one used a foot-operated bellows to get the air. So one had to stand on one foot and work the bellows with the other and try to get the soft glass together, and the first thing that happened, of course, is, the apparatus fell apart. But one couldn't really begin anything until one had it back together again.

Weiner:

Were you working on a solitary basis?

Oppenheimer:

Yes, absolutely. I don't remember how long, a month or so. But in the meantime talking to a lot of people, and got to know and get interested in what C. D. Ellis was doing.

Weiner:

What was he doing at the moment?

Oppenheimer:

Studying the level systems of thorium and radium. It was a great puzzle about whether the gamma rays of thorium started and went to the ground state. He had a very nice magnet, a permanent magnet which you could magnetize to any field you wanted to and it would stay there, so you could take long photographic exposures of electron lines without any ripple, and get very high resolution. He also had a good photometer for measuring densities. One could put lead in front of the source, and record the photo-electric lines. One could then compare the intensity of the internally converted lines with the intensity of the photoelectric lines. From this data one could compute the internal conversion coefficient, which gave one some indication of what type of transition was involved. Then one could assign consistent quantum numbers for the levels. It was a nice sort of puzzle. Radium has an awful lot of lines, and we finally got a reasonable level system for that, but heavy elements were the wrong place to begin to understand nuclear levels. One should begin on lithium.

Weiner:

You learned that later.

Oppenheimer:

Yes.

Weiner:

Before we get into the research that you actually did with him, I’m curious about this process of looking around. First of all, was it called "the nursery" then, or was that a term that was used later? What did they call the attic?

Oppenheimer:

I don't remember what it was called.

Weiner:

I've heard the term nursery.

Oppenheimer:

It may have been.

Weiner:

You worked on the project in a solitary way.

Oppenheimer:

It wasn't a project. It was an apparatus in the abstract.

Weiner:

An exercise. You worked on it by yourself. Were there other people doing similar things at the same time? Were there a lot of new people who'd come in?

Oppenheimer:

There was nobody there. There may have been times when there were several people, but when I was there, there was nobody else.

Weiner:

Who'd check on you, who'd confer with you, look over your shoulder?

Oppenheimer:

Nobody. I think when I finally said I'd had enough or when it was all put back together again, I had to tell somebody and they must have come and looked. But I don't remember that. Or it may be that they just thought I'd spent enough time there.

Weiner:

Who took charge of you administratively? Did you check in with Chadwick?

Oppenheimer:

Yes. I think so. And talked with Rutherford, and then this business of wandering around. Everybody was very nice. Kapitsa was there at the time.

Weiner:

On individuals — I'm curious about Rutherford. How was that arranged? Was it a casual thing or a formal meeting with him to get introduced and announce your arrival?

Oppenheimer:

I think I was taken probably by Chadwick to his office.

Weiner:

What was your impression of Rutherford? You'd heard of him before.

Oppenheimer:

I'd heard of him. I don't remember my first impression. I think he was a very imposing guy. I must have been slightly terrified of him, because I remember being invited to his house shortly after, to an event at his house shortly after I'd gotten there, and arriving a week early and feeling very chagrined.

Weiner:

It would have been a tea or something.

Oppenheimer:

Yes.

Weiner:

When you knew it was the wrong day, did you leave?

Oppenheimer:

Yes, I left. But every afternoon they had tea and sticky buns to which everybody including Rutherford went, and there was a lot of crosstalk about what everybody was doing. I don't remember how often, but maybe two or three times a year, he'd come and sit in the little laboratory where I was working and start talking to me about what I was doing, providing new ideas, or talking about something he had done. And I think he did this for everybody who was there. As far as one could tell, he managed to avoid most of the paperwork and spent almost all his time going around and talking to people, in the laboratories. I was extremely impressed with that.

Weiner:

You're talking about Rutherford?

Oppenheimer:

Yes.

Weiner:

His characteristic style was to really question, make you get to the issues involved; see you really understood, rather than being preoccupied with the details of the research?

Oppenheimer:

No, I think he did both. I think he was interested in how one knew that the photometer was properly calibrated, as well as in what was happening in the nuclei.

Weiner:

What about Chadwick? Did he play any of that role as well, or was he not so much on the visible scene as far as you were concerned?

Oppenheimer:

I saw him often, but he didn't come around and talk about what I was doing as much. I remember one time at one of these teas, I asked him why they didn't do a colliding neutron beam experiment to get the answer to —I've forgotten, some cross-section, and he said, "Well, go home and calculate it." I did.

Weiner:

When you looked into what other people were doing, what would that be, just walk around and see, the way Rutherford did it, observe? Did you talk with people?

Oppenheimer:

Yes, just to observe and talk with people, and ask — I mean, Cockcroft and Walton were there. When I first came they were building or rebuilding their device. Wynn-Williams was there.

Weiner:

Well, Oliphant was working on another device different from Cockcroft's. He was working on something for Rutherford.

Oppenheimer:

I'd forgotten that. Klemperer was there doing things with artificial radio-activity, I think.

Weiner:

As a visitor you mean.

Oppenheimer:

Yes, a refugee sort of visitor.

Weiner:

What was the date of your arrival?

Oppenheimer:

It must have been something like, late September, '33.

Weiner:

The Mond Lab was already separate — it was starting up — did you get over there at all? You mentioned Kapitsa.

Oppenheimer:

Yes, I got there a little bit. Not right at first. I remember Kapitsa talking about his machine and describing in great detail how he made the values by using drilling ball bearings before they were hardened and what he was trying to do. I remember they brought over a superconducting ring that was still a magnet from Holland. Ernest Lawrence came by during that time, and just after they'd observed neutrons at Berkeley, I guess, but not understanding quite why, — they asked him about the target. Everybody was sort of tolerant — it was really quite nice, because Lawrence hadn't gotten it all worked out together, it was just fresh, and all he knew was that the best target was beeswax and resin.

Weiner:

This would have been September of '33 because he was over for the Solvay Conference which was October, unless he was on his way back.

Oppenheimer:

No, was it the conference? It seemed to me I'd been there longer.

Weiner:

It was October of '33.

Oppenheimer:

OK, then I must have gotten there a little earlier.

Weiner:

Well, we could date when he came. He would have been working up that stuff for his Solvay talk.

Oppenheimer:

Yes. One really couldn't find out exactly what was happening, except that what one observed happened, but why? It was all fairly new to me, but I remember the discussions, back and forth.

Weiner:

Was Blackett there, still there?

Oppenheimer:

Yes, Blackett was still there.

Weiner:

In a few months though he left for London, '34.

Oppenheimer:

Yes, '34 he left — was it in the summer? I think he was gone by the next fall. I think he was there most of that winter. And Occhialini was there.

Weiner:

Right. Did you come in contact with them?

Oppenheimer:

With Blackett more than Occhialini, somehow. He had a huge cloud chamber there, I remember. It didn't work too well. J. J. Thomson was still around. Rutherford closed the Cavendish Laboratory at night, which was unlike other laboratories that I had been in or knew about, and his statement — at least I never heard him make it, but his statement was that if you hadn't done enough during the day, to think about it at night, that there was no point in going back to fiddle with it anymore.

Weiner:

Did you have any occasion to want to get back in the laboratory?

Oppenheimer:

Occasionally I did, and then if you did, I mean if you had a long exposure and you had to cut it off, there was no real trouble.

Weiner:

You didn't have to climb the wall to get in — there'd be some special arrangement made. A lot of things I want to ask about the Cavendish, but let's just get to the point of your looking around at the various things. As you describe the work with Ellis, it sounds interesting. Were there other things that interested you? For example, the cloud chamber was something that in later years you used and there were other things going on, work on the follow-up of the neutron, mass of the neutron and so forth, people like Feather working on it, Dee was somewhat involved. There was C.T.R. Wilson still doing a lot of cloud chamber work, there was Aston — somewhat isolated, I gather. I just wonder, what other things were contenders? There was also the work that Cockcroft was doing, the accelerator work.

Oppenheimer:

Asking about it now, I suspect that what led me into working with Ellis was that there was something fairly clear to do, and that it was a kind of continuation of spectroscopy that I'd gotten from Hopkins.

Weiner:

That would make you useful for him, too. Once it appealed to you for those various reasons, how did you announce yourself, announce your interest in it? How did you make arrangements with him?

Oppenheimer:

There was no great thing. I think I just went to him and said, "I'd like to do it." I think he said, "Why don't you just work on the thorium thing first?" He reported the work I’d done, it must have been at the Solvay Conference the next year, I guess.

Weiner:

You have it '35.

Oppenheimer:

'34, it must have been.

Weiner:

— Solvay was every three years — it couldn't be '33, that's too early — we can look it up, I have the records of the conference. You had a paper after you left, which is essentially this work on thorium.

Oppenheimer:

Yes.

Weiner:

How long did it take you to do the work? Did you do that problem first?

Oppenheimer:

Thorium first, yes, and that didn't take too long, as I remember. It was radium that took the longest time.

Weiner:

That's the one reported at the Solvay Conference.

Oppenheimer:

Yes. Then I did some more on it after that and got it a little straighter but never published it, I don't know why. I think because I realized it didn't — nobody could do anything much with it. And it was very odd, because after it was all disentangled, I don't know how many lines there were any more, 100 or more, but they broke up into two almost separate level systems, with only one, as though there was some sort of a forbidden transition there, but it never made quite — one couldn't get the quantum numbers well enough to have them make sense.

Weiner:

I'd like to ask a little more about the equipment, the resources. Once you announced that you wanted to work with him and he assigned you to a problem, then did you go ahead and build the different —

Oppenheimer:

No, he had the magnet. As I remember, I had to do some of the building on the photometer.

Weiner:

Did you have difficulty getting resources? Did you have to scrounge? I mean, the components that you needed.

Oppenheimer:

All one needed — well, for the photometer, I think one needed some vacuum tubes and maybe a lead screw, I've forgotten, but for the spectrograph all one needed were photographic plates. It didn't require any other resources — just sources.

Weiner:

What about vacuum tubes, any problems on getting them?

Oppenheimer:

No, not that I remember. But I may have just asked him and he got them.

Weiner:

Right, you didn't know about those problems.

Oppenheimer:

But it was really fairly economic research. Except the magnet itself had been an expensive item. I remember using the shop occasionally. They had both a shop operated by machinists and a staff shop, and the staff shop had only foot treadle lathes.

Weiner:

You could go and use it — by staff you mean laboratory people?

Oppenheimer:

Yes. [Pause for lunch.]

Oppenheimer:

I remember Barcroft, the physiologist, gave several talks, one of them I remember called "Mt. Everest in Utero," in which he was interested in why a fetus could survive in an oxygen deficient environment. He had watched people play tennis in the Andes and seen how skillful but how slow they were, and talked in general about what anoxia does for — he thought that's what was going on with the fetus — that it just didn't have enough oxygen to make it very active.

Weiner:

This was a university lecture or colloquium?

Oppenheimer:

He was in Cambridge, in I've forgotten which college, but there was quite a lot of exchange of this kind at the Cavendish.

Weiner:

Which college were you in?

Oppenheimer:

I was in Claire for a year. But later I didn't like to go to dinner there so much, so I became part of something that was called the Non-Collegiate Group, which had all the rules of the collegiate group except that you didn't have to go to dinner and so forth.

Weiner:

But you still lived at the college?

Oppenheimer:

I didn't live at the college, no. I lived in a private house in Cambridge.

Weiner:

So you gave up your assignment to quarters essentially.

Oppenheimer:

Yes.

Weiner:

What about lectures, seminars, colloquia at the Cavendish itself, involving the physics people? There were several. There was a Kapitsa Club that you probably were not involved in —

Oppenheimer:

Yes, I think I was, for a while anyway. Then, there was a constant stream of people giving talks, and I can't remember. I remember listening to Gamow. Then I took a course essentially on Lorentz, electromagnetics, listened to the lectures on that. But that wasn't part of the Cavendish. That was one of the university courses.

Weiner:

Who was giving lectures, do you know? Would it have been Dirac or Fowler?

Oppenheimer:

No, it wasn't Dirac. Neither one. I can't remember. Maybe it will come back to me, I've forgotten.

Weiner:

Any other courses?

Oppenheimer:

I took one other, but I've forgotten.

Weiner:

Nothing in theory though, for example?

Oppenheimer:

Let's see. I just can't — I'm sure there were, but I can't remember. I remember listening to Gamow. I remember listening to Rosenbluth. That wasn't theory, but it was —

Weiner:

Well, Rutherford himself gave some lectures. Did you hear those?

Oppenheimer:

One, but I've forgotten what it was about. I mean, people who worked there, like Chadwick, Kapitsa, Cockcroft, gave one, and of course, when Gamow came through and Lawrence — I don't think Bohr came through while I was there.

Weiner:

Well, it was the time his son died, in the summer of '34 — that whole period would have been — '33, I don't know.

Oppenheimer:

When did his son die?

Weiner:

In the summer of '34, Bohr's son. He was due to come — oh, that's an interesting question. There was a conference at London and Cambridge, an international conference on physics, in I think October of '34, in which there were two sections. One was on nuclear physics, one was on solid state. I wonder if you recall anything about Max Born, you may have recalled him, was at the Cavendish for a while.

Oppenheimer:

Yes, I remember.

Weiner:

Millikan came to this London conference. I don't know which part was in Cambridge, which in London, but there was a series of papers.

Oppenheimer:

I don't know if I heard Millikan there. I think not. No, I don't remember that conference.

Weiner:

Do you remember anything about the Kapitsa Club itself, about some of the discussions? There was the Cambridge Philosophical Society, which might have been a more elite kind of thing for the staff. There was the Delta Square Club, wasn't there? There was a whole proliferation of them at Cambridge at the time. Let's go back then to the laboratory itself. You mentioned refugees there. Did you see any significant influx of people at this time? Was there any impression you got that you recall now, that in fact there was a group of people coming in, significantly or visible at the laboratory or around Cambridge? Born, of course, was there.

Oppenheimer:

Yes. Klemperer was one that I saw quite a lot. The British government allowed people to come in, and Klemperer was there for a couple of years or maybe three. But then I remember, he didn't get a permanent position at the Cavendish. I remember how upset he was because the government wanted to send him to India, and felt really that they were treating him in a way which was way below what he deserved, sort of taking advantage of him because they'd been so nice to him. It was, after all, still Depression times. So he was very angry and I don't think he did go to India, and I've forgotten just where he went next, but — so there wasn't any sense that the refugees were coming and necessarily enriching the place, but they were treated to some extent as people who were being done a great favor. At least I got this impression in a few cases.

Weiner:

Rutherford was president of the Academic Assistance Council which was making a national appeal, but always making it very clear that there were a limited number of positions, and therefore no refugee was going to replace a British professor, but that additional funds should be raised to provide stipends to create additional posts.

Oppenheimer:

I don't think that happened.

Weiner:

Not at the Cavendish. There were very few. But people like Peierls and Bethe, a number of people.

Oppenheimer:

Where was Bethe during those years?

Weiner:

Bethe was at two places, Bristol and Manchester. And stayed for two years, then moved on, because again there was no permanent position, competition was very rough, and the Cavendish graduates themselves were competing for the same chairs. I've written something on that whole period.

Oppenheimer:

It was really quite sticky and you can see why.

Weiner:

This is also the time of increasing consciousness among certain parts of the British scientific community of relations to government. The Science and Society movement was developing on the one hand, which involved more of a left thinking in terms of the social uses, social role of science. Some others were concerned; you might call them reformers —

Oppenheimer:

Well, Bernal was writing and talking.

Weiner:

Were there discussions that you recall?

Oppenheimer:

Yes, vaguely.

Weiner:

Was Wooster there at the time?

Oppenheimer:

I think so. I'm pretty sure he was.

Weiner:

Do you recall —?

Oppenheimer:

— no, I don't remember. We played some music together, as I remember.

Weiner:

Flute?

Oppenheimer:

Yes.

Weiner:

I never met him. Was there any kind of a political atmosphere in the laboratory or in Cambridge itself — a period when there were debates and discussions?

Oppenheimer:

I remember listening to them. I went to some political meetings, some Socialist, Communists — arguing and talking — but not talking much myself, not being part of any sort of a group. But there was a lot of talk. But it was all very vague, most of it — as far as I remember. I don't know whether I read Bernal then or whether I read him after I went to Caltech.

Weiner:

He was very productive. Some of his writing came out in the late thirties —

Oppenheimer:

I saw an awful lot of Millikan's son, Glen Millikan. We drove — when I finally went to Italy, he and I drove down together, through the back side of Europe.

Weiner:

I knew of Clark Millikan. What was the relation of Max Millikan, was he a brother?

Oppenheimer:

I guess, I'm not sure, I think so. Glen was the youngest, I think, and he was a physiologist, and he was a mountain climber and fell off a rock, '35, '36.

Weiner:

He died?

Oppenheimer:

Yes.

Weiner:

I didn't know that. This was also the period, I think, when Kapitsa went to the Soviet Union for his regular summer visit and then came back.

Oppenheimer:

That was after I left.

Weiner:

— summer visit, and then come back — a great deal of discussion about it.

Oppenheimer:

That was after I left.

Weiner:

That was '35. I guess it was.

Oppenheimer:

One story I liked about Kapitsa was, one time I was off on a vacation and I found out I didn't have any money. It was just shortly after I'd been there, but I'd seen a lot of him in the seminars and talked to him, and it was late, nobody else was around, and I asked him if he would take me over to the bank and vouch for me so I could cash a check. He said, "Sure, sure," and we went over and took care of it, and then we walked away and he said, "Who are you?"

Weiner:

But you didn't have anything to do with the people in his lab, such as Schoenberg?

Oppenheimer:

No. I didn't.

Weiner:

How about the theorists, people like Fowler and Dirac, did you have any interaction at all with them?

Oppenheimer:

No. The people I did have some with were Mott and Taylor. There was one paper on internal conversion that we did together.

Weiner:

How did that come about?

Oppenheimer:

I had some data and they had some theory. Sort of a joint thing, to which I didn't contribute terribly much.

Weiner:

You weren't working on a joint project with them, it was just that your data —

Oppenheimer:

The whole business of disentangling these level systems relied heavily on using internal conversion data, and some of the things that I'd gotten seemed not to fit, so I think I went and talked with them, and then they did some more calculations, and the paper was the result.

Weiner:

I see. This was published in '36.

Oppenheimer:

It was written while I was there.

Weiner:

Talking about your work there, did you get any feeling about the focus of the laboratory — that is, there obviously was a great deal of nuclear physics going on, but was it clearly in the minds of people a nuclear physics laboratory? Or was it considered, in effect, that there were lots of different groups working there, nuclear physics among others?

Oppenheimer:

Much may have been going on that I didn't know, but the two main things that were happening, things that were talked about most, were the cryogenics and the nuclear physics. And I don't remember much else. There may have been, I just —

Weiner:

Probably there was some ionospheric work going on, C.T.R. Wilson's work —

Oppenheimer:

Yes. That's right, there was some gas —

Weiner:

Also the radio research, too.

Oppenheimer:

Oh, I didn't know about that. There was gas discharge work. But that didn't shape any place really till after the war. All the research on plasma was really pretty bad at that time. So really, those two things really dominated the place, at least while I was there, as far as I could know.

Weiner:

This was also the time when cosmic ray phenomena — the positron, pair production work of Blackett and Occhialini — do you recall any discussions on that?

Oppenheimer:

No details, except that it was discussed a great deal, and as I remember, Rutherford was not that interested in it for some reason. But I'm not sure of that. But a lot of other people were. Chadwick was. What else?

Weiner:

Goldhaber was working with Chadwick about this time on photo-disintegration, the neutron. Do you recall that?

Oppenheimer:

Yes, pretty well, yes. I can't remember too many of the discussions, I'm sorry. But remember the work that my brother and Melba Philips did on this process a year or so later.

Weiner:

How about trips during the period? Did you travel to other places? Visit other places, other countries?

Oppenheimer:

I took vacations, but I didn't — oh, I guess I did visit the Rosenbluth laboratory, where they were doing long range alpha particle work, in Paris, but only very briefly.

Weiner:

Was he working with the Curie laboratory?

Oppenheimer:

Yes.

Weiner:

Did you meet other people there at the time, Joliot, or Irene Curie?

Oppenheimer:

I think I must have met him in Cambridge. Or at some — no, in Cambridge.

Weiner:

How did you decide you'd had enough, that you'd accomplished what you started to do? During the period you did three pieces of work and ended up with published papers — the Solvay Conference report with Ellis —

Oppenheimer:

Yes. The Mott thing and —

Weiner:

— with Mott and Taylor, and your own paper — all of them, if your bibliography is correct, ending up after you left in '36.

Oppenheimer:

Yes, they came out after I left.

Weiner:

How did you decide it was time to move on?

Oppenheimer:

Bernardini came by, and we talked about quite a few things, and he invited me to come to Florence. I don't think I knew that I would — well, I'd finished the Radium C' level system analysis, and the simple thorium level system was well in hand, I think it became a little clear to me that we weren't really learning much about nuclei from this approach. So, in a sense, I had done, I'd finished what I was doing and it was a question of either starting up something new — and I was sort of intrigued with the idea of going to Florence.

Weiner:

We were talking about Bernardini. He came on a trip?

Oppenheimer:

He visited there. [The Cavendish]

Weiner:

This would have been some time in '35 — do you recall when it was, summer or fall '35?

Oppenheimer:

It must have been the fall of '34, I would think. I went to Italy in January of '35, as I remember.

Weiner:

I see. The only thing I know is that you were there in Cambridge the dates '33-'35, but there's no way of telling when in '35 —

Oppenheimer:

Yes. I think I left very early in '35.

Weiner:

So essentially you were there about a year and a half.

Oppenheimer:

A year and a half.

Weiner:

When Bernardini offered the opportunity to go to Florence.

Oppenheimer:

— it wasn't a job, I just went.

Weiner:

You said you didn't know Occhialini very well.

Oppenheimer:

No. He was in Florence when I got there, so he must have left — I don't know when.

Weiner:

He left some time in '34. He had to return. Actually he only came to Cambridge supposedly for one year — and then in London, he went to London with Blackett. So he was back in Florence. Well, this is a completely new field of work for you.

Oppenheimer:

Yes.

Weiner:

They were focusing on cosmic rays?

Oppenheimer:

No, Bernardini, while I was there, was interested in measuring the ranges of alpha particles and protons from artificial radioactivity — using neutron sources. And what I did there with him was entirely instrumentation. We developed a set of proportional coincidence counters, between which one could put thin films and measure the range fairly accurately.

Weiner:

Did you like this? This is more instrumental, going back to your very early interests, where the focus of the work was to develop something. Did you like that better than the work you'd done in the other place?

Oppenheimer:

No, I can't say I liked one more than the other. The work in England was really a nice puzzle and took a lot of measuring. It was very nice. So I can't say I liked one more than the other. The work in Italy was interesting, because it involved counter techniques — I knew nothing about any electronics of coincidence, and I learned about that and I learned about proportional counters. I knew only a little from Klemperer about Geiger counters, and proportional counters. I suppose that's one — maybe that was one of the reasons Bernardini asked me to come there. I've forgotten.

Weiner:

Who did you find when you came to Florence? There was Bernardini.

Oppenheimer:

And there was Occhialini, and a lady physicist by the name of Boccarelli and a young man whose name was Racah —

Weiner:

— Julio Racah —

Oppenheimer:

I think that was the main — oh, no, Emil Capo da Lista, who later went to Cal Tech.

Weiner:

How long did you stay?

Oppenheimer:

From January till September.

Weiner:

How did you find the work and the life?

Oppenheimer:

Oh God, it was a wonderful time for me. Occhialini — we lived in the top of an old sort of manor, a big stone building. It must have been a great family castle at one time, and we had rooms next to each other in the attic, and I got to know Occhialini, got terribly fond of him. And we'd work, in the lab, almost everybody, till late at night, and then everybody would quit and we would wander off together to a street corner where we would part to go in different directions — and everybody would stand on the street corner and sing for half an hour before they — not me, but everybody else would sing — before they dispersed.

Weiner:

Sing? What?

Oppenheimer:

Just Italian traditional songs.

Weiner:

The people you describe?

Oppenheimer:

Occhialini, Bernardini, all of them.

Weiner:

At the end of the day.

Oppenheimer:

Yes.

Weiner:

This is without drinks?

Oppenheimer:

Without drinks, and it was entirely — if something didn't go well, everybody was — I mean Bernardini would be so gloomy, and if something started to work, people would dance around and hug each other. It was a great change from the Cavendish.

Weiner:

More of an expressive style.

Oppenheimer:

Yes, and very, very — very sensitive to the events of the day.

Weiner:

You said you didn't know Occhialini well in Britain, it would have been interesting, your evaluation of him in that other environment.

Oppenheimer:

I know.

Weiner:

And was the work primarily —

Oppenheimer:

Occhialini was building, if I remember rightly, I'm not sure, a cloud chamber. I'm not sure.

Weiner:

Yes, they had developed a very interesting automatic cloud chamber, and he was doing some work on it.

Oppenheimer:

Yes, that's right.

Weiner:

But it was pretty soon after that he left, because the situation was really —

Oppenheimer:

Yes, that's right.

Weiner:

Now, let's talk about the politics there, Fascist Italy. Were there discussions that you recall at the lab? First of all, you didn't mention Garbosso, who was the — wasn't he the boss in Florence essentially of the physics group?

Oppenheimer:

Yes, he was head of the laboratory but had very little contact with the people we were working with. I remember one story, that he came around to see what Bernardini and I were doing, and since — something happened only when two counters fired — he said, "That's a great example of resonance." And Bernardini didn't contradict him, because that was his favorite topic, was resonance. So Garbosso was just off there someplace with everybody not paying any attention to him.

Weiner:

He was also by this time, I guess, occupying a position as putatore or something, as equivalent to the mayor, governor of Florence in the Fascist regime.

Oppenheimer:

But everybody, I gather, had paid their dues to the Fascist Society. Most of the physicists did not regret paying these dues, they said that the Fascists did have lots more meetings of people where they got together and talked about issues, and they thought that these meetings couldn't do any harm and might be a good direction. They didn't feel any threat or any betrayal of themselves in paying their dues to this. I was somewhat shocked at this news. They saw, seemed to see, what Fascism meant, but felt that it couldn't really take root in any evil form in Italy. And there was a battalion of carabinieri — there was a little military headquarters just below the laboratory and the soldiers would sit around and sing, and joke, and come and go sort of as they pleased, without any overt signs of militarism. They all looked very relaxed. But the next year, Abyssinia broke out. That all changed.

Weiner:

Was Racah there? Since Racah was Jewish, was he feeling any qualms about this?

Oppenheimer:

He didn't express any. He was a very quiet sort of guy, very strange in some ways. He was making ball point counters at that time, and, in order to get them to work, you have to get the little bead on the tip of a wire very, very clean, he'd brush the dust off with a small camel's hair brush. I remember going to lunch with him once, and he looked at his soup and took a wooden spoon and flicked the little dust away — but as far as I know, he also, I can't be sure, but my impression was that he, too, paid his dues. And wasn't he drafted then?

Weiner:

I'm not sure.

Oppenheimer:

I think he was drafted then and was killed, wasn't he? I'm not sure.

Weiner:

He wasn't killed but he went to Israel. He ended up in Israel.

Oppenheimer:

Yes, well, there was one —

Weiner:

— but he did die, I'm not quite sure when.

Oppenheimer:

Yes. I think he was drafted and sent to Abyssinia.

Weiner:

A number of people were. Amaldi in Rome was.

Oppenheimer:

So things changed very radically just a year afterwards, but this sense of "we'll go along with it, it isn't polluting us" and "and it is doing some of the hoi polloi some good:" — was very prevalent at the University.

Weiner:

What about Occhialini? Later on he left because of Fascism, but in this period you didn't know of his anti-Fascism?

Oppenheimer:

I knew of his anti-Fascism, but I don't think he felt the threat of it.

Weiner:

What were the relations of the Florence group with other Italian physics groups, particularly the group in Rome? This is when the Fermi group was really in their very active period.

Oppenheimer:

Bernardini had been a student at Rome, and I think the relationships were good, but as far as I could see there was very little contact. I mean, I may not have been aware of what there was. But nobody had gotten anything done there and found out anything, so there wasn't much reason for reporting what they'd done. I do know that when I left, Bernardini was terribly anxious, I think actually it was a version of this paper he may have written up for an Italian publication, but he was very anxious that I write one up and have it published in, what was the name of the journal? It's gone now, the one in physics instrumentation.

Weiner:

Not REVIEW OF SCIENTIFIC INSTRUMENTS?

Oppenheimer:

Yes, REVIEW OF SCIENTIFIC INSTRUMENTS.

Weiner:

That still exists.

Oppenheimer:

It does? I don't think so.

Weiner:

I think you're right. I was looking up a copy the other day. I'm not sure — I guess you're right.

Oppenheimer:

The feeling I got was that it was terribly important that the work of Italian physicists be published in an American journal, and whether this was just for prestige or with some notion that they wanted to have the option maybe of being known in America in case they wanted to come here, I don't know. But he made a great point of that, I felt.

Weiner:

Now, you said the results weren't coming out. You meant in terms of experimental results that would influence somebody else's work?

Oppenheimer:

Yes.

Weiner:

Were there discussions though about current physics?

Oppenheimer:

Yes. Not great arguments that I remember about it, but sort of reporting what we read or what was happening.

Weiner:

That's the period of the neutron work being very active.

Oppenheimer:

Yes.

Weiner:

What about students there? You talked of staff essentially. You of course didn't have any responsibilities, but did you have a feeling that there were groups of students who were being brought into the —

Oppenheimer:

— there weren't very many around the lab. Bernardini taught. I don't think Occhialini was teaching at that time. But Bernardini had some classes, and it all seemed sort of remote. I mean, he'd disappear for half a day, come back —

Weiner:

But the lab was almost as if it were sort of a private research lab, you wouldn't know you were in a university, had other responsibilities —

Oppenheimer:

Yes.

Weiner:

What about the resources there compared to what you knew about in the Cavendish, in terms of the availability of materials?

Oppenheimer:

Oh, they were terribly poor, and if I had to get anything from America it took forever.

Weiner:

What about sources? You were using the counters on something, so were there sources available?

Oppenheimer:

Yes, they were. We used alpha particle sources. They were available. We also had neutron sources at that time.

Weiner:

This will show up in the article.

Oppenheimer:

I think we must have, because I had to calibrate the counters for protons.

Weiner:

During this period did you learn to speak Italian when you arrived, or had you some?

Oppenheimer:

I'd studied it a little bit before I left, and then learned it after, from the first week I was there, I gave a lecture on the level system of thorium C in Italian, but I was corrected pretty often by the audience. I kept using the word for falling from one level system to another as "tomberi" instead of "caderi" and every time I did it, I heard the chant: "cade" — "tomberi" was a corruption of the French word.

Weiner:

The audience would have been who, in this case?

Oppenheimer:

There were more people there than were working in the lab. But it was very shortly after I arrived, so I don't know who they were. Other teachers around the institute and on the staff.

Weiner:

You stayed there a good part of the year.

Oppenheimer:

Yes.

Weiner:

Did you go on anywhere else during this year?

Oppenheimer:

No. Getting there, Glen Millikan and I had done a sightseeing tour by driving down through the Balkans and Yugoslavia. But I didn't visit any other place.

Weiner:

How did the decision come to leave there, and also how did you make the decision to go on to Cal Tech before you left there? I don't know if you went directly to Cal Tech or not.

Oppenheimer:

It was a very hard decision to make for me, because I liked the people and I liked the work and I liked the place… (off tape)

Weiner:

You were talking about Florence, saying you felt you weren't learning anything.

Oppenheimer:

Yes, I wasn't studying. I was learning through the lab work — but I wasn’t taking any courses, and I really needed some, because I'd sort of rushed through college and I didn't do much coursework at the Cavendish.

Weiner:

All right, then how did you decide to go to Cal Tech? Had you considered other places as well?

Oppenheimer:

I doubt it. My brother was at Cal Tech, which made it sort of attractive, and I think it was another of these things where I don't even remember applying, but I probably did, because I had a tuition scholarship when I went there, so I must have done something.

Weiner:

You say he was at Cal Tech. He was also at Berkeley.

Oppenheimer:

Also at Berkeley, yes.

Weiner:

Did you consider Berkeley as a possibility?

Oppenheimer:

No. Not really. I went to Cal Tech, and because I had done that work with Ellis, I knew about beta ray spectroscopy, and so I knew what I wanted to do when I got there, and got permission from Charlie Lauritsen to make a beta ray spectrograph, and it fitted in. They didn't have any there. It fitted in with their program. It was very nice to be a beginning graduate student, knowing what you wanted to do, rather than just, as so many of them do now, just taking courses and finally asking somebody "What should I do?"

Weiner:

Right. You got there I assume September or October of '35. So the problem was immediately selected. Was it clear, the guy you were working with was Charlie Lauritsen, was he your advisor essentially, in charge of the experimental program?

Oppenheimer:

Right. Right.

Weiner:

There was no question of Millikan being involved in any way, was there?

Oppenheimer:

No.

Weiner:

Was your acquaintance with Glen Millikan any influence about Cal Tech?

Oppenheimer:

I doubt it.

Weiner:

I see. Let's talk for a minute about the coursework, since you wanted to do that, what did you have? Was it a plan or a random thing, that you took courses as they were available?

Oppenheimer:

There were a number of required courses, and I started out with those. I've forgotten, I could look up what I did. I took a course in electricity and magnetism with Smythe, and relativity with Tolman, mechanics with Zwicky, and then a general sort of course with Houston, and a course in group theory with I've forgotten whom. We used Weyl as a text.

Weiner:

Epstein?

Oppenheimer:

I took thermodynamics with Epstein.

Weiner:

How about your brother, did you take anything with him?

Oppenheimer:

No. I listened to his lectures.

Weiner:

I think most people did.

Oppenheimer:

— and took notes.

Weiner:

Very few people admit to actually signing up for the course, they were afraid —

Oppenheimer:

I don't know whether it was a course that one signed up for. I don't even know if it had a name.

Weiner:

But there were these nuclear — notes on nuclear physics —

Oppenheimer:

Yes, I took elaborate notes. But I don't think — I don't believe it was something that — nobody got a grade in it, as far as I remember.

Weiner:

But your other courses with Tolman, Zwicky, etc., you did.

Oppenheimer:

Yes.

Weiner:

Then there were no lab assignments, it was just working in the lab?

Oppenheimer:

Yes. I was not a teaching assistant there.

Weiner:

So that meant you could devote whatever time was free from courses to your own research.

Oppenheimer:

Yes.

Weiner:

What about resources there? Was there any problem getting what you needed in order to build things?

Oppenheimer:

No. That was good. I designed the magnet and got some cost estimates and got Charlie's OK. Built — went to the shop and built a vacuum chamber and charged it, and there was never any objection. But the x-ray spectrograph wasn't a major project.

Weiner:

This was in Kellogg.

Oppenheimer:

Yes.

Weiner:

Did you have a room, or a corner of a larger room?

Oppenheimer:

I had a room, right on the corner. Window just facing the courtyard, of the Van de Graaff lab. First thing, when I arrived at Kellogg, Charlie had just opened up a big X-ray tube that they'd developed and he said, "Come here, Frank, and smell a vacuum." In those days the way one made a vacuum was to paint everything with shellac, and then the shellac, the vapor decomposed, and it really made a foul stink.

Weiner:

It would be good to know who else was there as a contemporary of you working in a similar —

Oppenheimer:

— Delsasso was there —

Weiner:

— was he a student then?

Oppenheimer:

He was a graduate student. And Stevens and Willie Fowler and Tommy Bonner. The second or third year I guess that I was there, Tomlinson came in and worked with me, later went to Princeton. And Charlie was wonderful. Every Friday night, you know, he had everybody in Kellogg over to his house. It was very nice because one talked about the work, talked about what was being done. I don't remember too many — there were regular seminars, but an awful lot of the discussion went on at these Friday night meetings. They were irreproducible. I've never found another situation where that same kind of thing worked as well. They were half parties, half general reviews of work and physics.

Weiner:

— this was the after dinner conversation. You say, half parties, then there'd be something to drink?

Oppenheimer:

Yes. Lots to drink.

Weiner:

Hard liquor or beer?

Oppenheimer:

Both.

Weiner:

This would involve the graduate students, faculty, wives, girlfriends, as well?

Oppenheimer:

Faculty, students — not too many other faculty. It was mostly graduate students around Kellogg, and a few miscellaneous friends, that were regulars at it even though they weren't physicists, people like Stuart Harrison, a doctor.

Weiner:

He's the man who got into radiology work?

Oppenheimer:

Yes.

Weiner:

Would people bring their wives? It was a social occasion as well.

Oppenheimer:

Yes. That's right.

Weiner:

The main topic of conversation was physics very often.

Oppenheimer:

Yes. That's right. Ask Jackie about that when you see her.

Weiner:

I will. When you say the people around the lab were involved — Tolman, Zwicky, etc., wouldn't necessarily be there?

Oppenheimer:

No. Very seldom would they be there.

Weiner:

It was a youngish crowd, then.

Oppenheimer:

Yes.

Weiner:

Lauritsen would be by far the oldest person.

Oppenheimer:

That's right, yes. And Tommy (Lauritsen) was always around. I think he was still — in school or college? Maybe a mixture of both, I've forgotten.

Weiner:

Toward the end of your time there, he went over to Copenhagen, didn't he?

Oppenheimer:

After I left.

Weiner:

He came back very, very late, in terms of the war.

Oppenheimer:

Yes. He must have been in college then.

Weiner:

When your brother would come down, he would be involved as well?

Oppenheimer:

Very much.

Weiner:

Did you ever travel up to Berkeley to join him on any occasion, socially or otherwise?

Oppenheimer:

I'd go up, Jackie and I'd go up quite often and stay over a weekend or a holiday, yes.

Weiner:

You were married in 1937, was it?

Oppenheimer:

Let's see, I have to — it must have been '36.

Weiner:

I had something that said '37, on some biographical —

Oppenheimer:

I got there in the fall of '35. So I think I might have gotten married in the fall of '36.

Weiner:

We hadn't mentioned the cosmic ray people, Anderson, Neddermeyer, Neher — and Millikan himself. Did they have anything to do with this same kind of thing?

Oppenheimer:

They weren't active at Charlie's evening things. I saw quite a lot of Carl Anderson and Neddermeyer.

Weiner:

You saw them on campus.

Oppenheimer:

Yes, mostly on campus.

Weiner:

How would you characterize this period? Here you'd been in Europe for several years, you'd been at the Cavendish, in Italy, you'd had considerable experience in research, you'd published already — the papers came out while you were there. You were sort of filling in the gaps in your education. In terms of courses. Did you feel very much a student, or did you feel you were sort of launched on a real research career already? I'm trying to see whether you regard this as another transition stage, preparation stage, or in fact you're doing your life's work.

Oppenheimer:

No, I think right away when I came there, I knew what research I wanted to do and adding a facility to the lab that it needed. I felt really primarily part of the research thing. The school was just blending in with it. There wasn't this business of getting ready to be a physicist. Which is so terrible now for so many students, the whole business of really going to school from the time they're four to the time they're 26, getting ready to become something.

Weiner:

And then finding out maybe that —

Oppenheimer:

— there's nothing for them to do or that's not what they want to do —

Weiner:

That's right, or they're ill prepared for what the realities are.

Oppenheimer:

People were very jazzed up about what they were doing. Willy and Charlie were doing nice things, precision things, almost for the first time. The cyclotron, at that time anyway, couldn't make precision measurements. The Engineering Department was testing the transformers for the Boulder Dam Power Line, in the same place, Building 1, that housed the Van de Graaff generator. Across the alley they were grinding the mirror for Mt. Palomar.

Weiner:

Well, the mirror wasn't being ground there, but over on Santa Barbara Street?

Oppenheimer:

Just across from Kellogg there was the big astrophysics lab and machine shop.

Weiner:

You mentioned that Lauritsen's discussions sort of added camaraderie to the whole thing. What kind of relationship did you perceive Millikan having to what was going on in the laboratory? Was he regarded by this time as the administrator who had very little to do with any of the real science going on?

Oppenheimer:

I think so, yes. I think he had to approve, and I remember sort of vaguely Charlie talking about convincing him to provide money for his program. It seems to me quite a lot of the money came from some separate sources for Kellogg.

Weiner:

Well, there was Kellogg money itself, I guess.

Oppenheimer:

I mean for the operation of that. But Millikan at that time was sort of selling something about cosmic rays which nobody believed.

Weiner:

Yes, well, this was his big debate with Compton, for example. You say nobody — nobody in the field believed, but what about at Cal Tech, was he already somewhat isolated?

Oppenheimer:

Yes.

Weiner:

This would put people like Anderson and others in a somewhat difficult position. Because they were directly involved in the work.

Oppenheimer:

I think, at least toward the end of it, Anderson had started doing some balloon work, and the data was so confusing that I don't think he knew whether Millikan was right or wrong, and he may have felt embarrassed because Millikan was using it prematurely. I would just have to guess that I didn't know it.

Weiner:

I was just wondering if there was anything you perceived. I don't think it was a problem as far as he felt. Do you recall the impact of the discovery of what was then called the mesotron by Anderson and Neddermeyer? You must have been there at the time.

Oppenheimer:

When was that?

Weiner:

'36 and I guess '37, I'm not sure what the overlap was.

Oppenheimer:

One other thing, it's strangely timeless. I remember the enormous satisfaction one got, and constantly going over the Yukawa arguments as everybody did, but exactly when that happened, I don't remember.

Weiner:

About '37, I think. But you remember the discussions on this, about the relation of this discovery to the Yukawa theory.

Oppenheimer:

Yes. And it all seemed so neat. And let's see, you'll probably remember better than I do, when people began to realize there was something — certainly by the war, by '39, people realized that wasn't —

Weiner:

Not so soon. There were certain doubts, but the Japanese independently had some doubts during the war, and results from Italy, just after the war, raised further doubts — by about '47, there were already a couple of theories, that there were two mesons, and then Powell's work —

Oppenheimer:

Yes. I remember this happening before the war, that people had seen that the cross-sections were too low to make it the exchange particle.

Weiner:

I agree with the first part, you could see difficulties, but I don't know that they were ready to give it up.

Oppenheimer:

No, but they'd seen that it wasn't doing what it was supposed to do.

Weiner:

That there was a problem with the thing, I agree. Well, another thing about the period, the atmosphere of the thirties, in terms of the Depression hitting, must have affected people's expectations about careers, jobs and so on, shattered a lot of illusions about the world — and the specter of war, as you probably saw when you were in Italy... Was this reflected in a kind of social concern and political discussions within the Lauritsen circle? Were there good political discussions and arguments?

Oppenheimer:

Yes. I mean, Jackie and I joined the Communist Party about 1937 and so if there hadn't been political discussions, we would have started them. So there was a lot of this. Willie Fowler said that the reason he was a physicist was, he didn't want to have to worry about people, and he was really getting upset because he did have to worry about people. Charlie's heritage of Denmark certainly made him see that — rather clearly, the kind of mess things were in. He used to make great jokes about the capitalist system, how great it was because one kept making new things without ever having to pay for anything. I saw quite a lot of the Tolmans because my brother knew them and loved them very much. I played my flute with Ruth Tolman who was a great pianist.

Weiner:

Was there any division, real sharp debate which interfaced in any way with relationships? The position you and your wife had taken was presumably known by other people.

Oppenheimer:

Yes.

Weiner:

Were other people sympathetic or hostile?

Oppenheimer:

Not the people I saw. There may have been some in the background. I wasn't offered a post-doc at Cal Tech, and whether this was my physics or my politics, I don't know.

Weiner:

When you expressed yourself in a personal way, making a decision for the Communist Party, was it reflected in any other kind of political activity that therefore would project you into the consciousness of other people?

Oppenheimer:

Well, there were a number of issues. Among the prominent ones at that time was the war in Spain. I remember giving a concert with Ruth Tolman to raise money for that cause.

Weiner:

You mean a recital?

Oppenheimer:

Yes.

Weiner:

Was it in someone's home?

Oppenheimer:

No, it was in a little auditorium, a little theatre.

Weiner:

A benefit.

Oppenheimer:

Yes.

Weiner:

Did you raise much?

Oppenheimer:

I don't remember. It seemed satisfactory. We had many parties at our house. Then there were other organizations. There was the beginning of this thing with the long name, this FAECT, Federation of Architects, Engineers, Chemists and Technicians. It's cute that they left out physicists before the war.

Weiner:

This was a sort of a trade union.

Oppenheimer:

Yes. We spent quite a lot of time at meetings, political meetings, Jackie and I did. There were many issues. There were little issues like fingerprinting on license plates, and the Workers Alliance was a rather active organization. The CIO political arm, the Labor's Non-Partisan League, didn't really start up till about 1939. And we got very involved with that, which took considerable time away from research.

Weiner:

How did you get started? You mentioned in '37 you joined the Communist Party, but was there anything in your earlier experience that made you (1) political, (2) left? Was it a natural progression from something earlier, or a particular series of events?

Oppenheimer:

I don't know — I have no idea, really, how this came about. The school I went to used to have things called ethics classes — in very early grades — in which one did discuss sort of moral issues and social issues and argue back and forth with somebody who led them. Some of the kids that I knew in high school were fairly left. I remember going with some of, them to a concert in Carnegie Hall which was a sort of "down with the bosses" concert because they didn't have a conductor, and everybody clapped when they all came in on time. It was a ridiculous affair. Then, some of the people I knew, many of the people it turned out that I got to know well in Baltimore were quite left. But I, at that time, never liked to talk about politics, and used to tell people, unless I meant to do something about it, I didn't want to talk about it. But I apparently had a lot of these influences from people I liked to listen to them. As I said earlier, I remember going to a meeting in England to listen to some Communist talk about why it was a good thing — and being rather dismayed by his argument, which was that since capitalism had made such a mess, Communism would solve it. It sounded to me sort of empty. But then more issues came up when I got back to the U.S. in 1935. In 1936 Jackie and I simply saw a clipping about joining the Party in the newspaper and clipped it out and sent it in, and decided to find out more about it. Read a lot.

Weiner:

Certainly not the PASADENA STAR, would it be more likely PEOPLE'S WORLD or something?

Oppenheimer:

It may have been the PEOPLE'S WORLD. I don't think it was a Pasadena paper. It could have been. We were really quite overt about it, completely overt about it. But I'm sure, I know from other friends, that there was, at that time, plenty of resistance to the left. I remember a friend of my father's an older man, saying he wouldn't send his son to a college at which I was teaching.

Weiner:

You got that through your father?

Oppenheimer:

No, his friend visited us.

Weiner:

Did you encounter this kind of hostility from people at Cal Tech?

Oppenheimer:

Not from the people I knew there. I guess I don't know how many people around there said and felt terrible things about us because of it. But nobody was impolite about it.

Weiner:

Nothing to interfere — nothing to prevent you holding the scholarship —

Oppenheimer:

No, nothing at all. I'm sure Charlie wouldn't have let that happen. It might have come up, for all I know.

Weiner:

You mentioned issues, public issues. Did you do a study of Marxist literature?

Oppenheimer:

Yes. I read all of Marx and Engels and Lenin and labor history.

Weiner:

Was it only after?

Oppenheimer:

It was after I joined.

Weiner:

So the issues for example, the trade union issue, Spanish Civil War —

Oppenheimer:

A little later, the migrant issue. Unemployment.

Weiner:

When was the American Peace Mobilization? That was about that period — the issue about whether to get involved in the war, '39 or so.

Oppenheimer:

Yes, that happened while we were at Stanford, in which there was sort of temporary alliance with the American Firsters.

Weiner:

Isolationists, particularly at the time of the Hitler-Stalin Pact.

Oppenheimer:

Yes.

Weiner:

OK, so your life then — you got married, got involved in politics, you were doing research —

Oppenheimer:

I was playing the flute.

Weiner:

And playing the flute, sounds like a pretty good life. And you had good companionship.

Oppenheimer:

Yes. The whole business of my education, which I think was not necessarily unique, is so — I'd like to write it up in some way, because it's now almost unbelievable. I don't think many people of that age now would even believe that my experience is a possible thing in education: the contacts with faculty at school and at college, and later with colleagues, the richness of the courses, — I remember as a freshman the business of learning calculus. Just the thrill of finding out about a limit and the notion of being able to go to a limit and have things get continuous. Well, in almost all my courses, except unfortunately the biology courses, the enormous satisfaction of learning. And I had a terribly good history course, Professor Lane at Hopkins. I just wouldn't dare miss a lecture, it was so wonderful. And that whole sense of one marvel after another coming up was so foreign to what education seems to be right now.

Weiner:

It depends on the student and on the teacher, I guess. I think still some of the young people have that same sense.

Oppenheimer:

They're few and far between.

Weiner:

Well, it depends very much on the environment and the teacher as well. How did you get to the point of the Ph.D. exam at Cal Tech? Did you have to prepare certain fields that you took examinations in?

Oppenheimer:

We had to take the required courses, and write a thesis, and take an oral. The oral wasn't trivial, but I don't remember it as being grueling either. The only thing I remember is, somebody asked me a question about who discovered — it wasn't the photoelectric effect, it was something else, but it was something Millikan had discovered and I didn't know it. That's the only thing I remember being embarrassed about.

Weiner:

Was Millikan on your committee?

Oppenheimer:

I think he was, yes.

Weiner:

Do you recall the others?

Oppenheimer:

No — I think Houston was on it, and Charlie, probably Tolman, somebody else, maybe Zwicky.

Weiner:

The actual thesis research was on the positron spectrum.

Oppenheimer:

Of nitrogen, yes.

Weiner:

How did that flow from the original work you'd undertaken from the moment you came practically?

Oppenheimer:

Well, because one of the problems with the nitrogen-13 spectrum was that some people had found the gamma ray and other people hadn't, and so the business of looking for gamma rays was very close to what I'd done with Ellis.

Weiner:

But the problem that you eventually ended up with was not necessarily started with your work with Ellis?

Oppenheimer:

It was a byproduct of that. I'd done several other spectra, too, and the thing that people were interested in at that time, the difference between the Fermi and the Konopinski selection rules involved studying the shape of the high energy end of a spectra to see how it came in tangent with the axis. The shape of the tail was also relevant to the question of neutrino mass. at the high energy tail, you could — I've forgotten exactly why — one was a fourth power, the other was a square, and so it was possible to find out which was going on, trying to find the forbidden and then allowed transitions and compared. So since that came up after I started, that was one of the things. I don't think I got an answer very precisely.

Weiner:

You did it in nitrogen, and you did sodium 22.

Oppenheimer:

Yes. I'd have to look it up.

Weiner:

I haven't seen the paper, I might find it — it was only published as an abstract, I gather.

Oppenheimer:

Yes, and then I gave a talk about it at an APS meeting at Stanford.

Weiner:

All right, this takes us to the end of 1939. You say you didn't get a post-doc. Had you applied for one?

Oppenheimer:

I don't think I'd applied for one. I may have asked Charlie. Then I went to Stanford, and that was entirely my brother's doing. And it was in most ways a mistake. He'd known Felix Bloch. And Bloch was doing things I wasn't especially interested in — wanted me to get an old neutron tube going, which was a dilapidated old thing.

Weiner:

When you asked Charlie Lauritsen about staying on, did he imply it would be difficult because of politics?

Oppenheimer:

No. Because I remember that. I just said I'd like to stay here, and then somehow nothing ever came of it.

Weiner:

So the position at Stanford, you came as an assistant — this was the first time you were getting paid?

Oppenheimer:

Yes. It was very low pay, $75 a month. Which was standard.

Weiner:

Was your wife working at the time?

Oppenheimer:

No.

Weiner:

I saw her name on a paper with Willie Fowler. How did she get involved in that?

Oppenheimer:

She was the world's first scanner. She analyzed cloud chamber pictures.

Weiner:

I see. But she had no background in physics?

Oppenheimer:

No, she had no preconceived biases about pair production. The first year at Stanford we were heavily involved in politics.

Weiner:

This would have been starting about September, '39. The same issues? To be involved is to be in a party, to express yourself, but did this mean getting other people too, organizing?

Oppenheimer:

Organizing, it was working in a teachers' union, and it was writing, I think it was a weekly publication for the Labor's Non-Partisan League, a little bulletin which I did at one point, they wouldn't allow me to hold any more meetings in the Palo Alto Civic Center. I was specifically forbidden to hold any more meetings.

Weiner:

At this point you were quite publicly involved. Did this cause the people at Stanford any embarrassment?

Oppenheimer:

I think so.

Weiner:

Any way that you felt it?

Oppenheimer:

Yes, I think, there again there was a combination of the fact that I did not produce very much physics, because I was so busy with other things, plus the fact that they didn't really want me to stay. I could have stayed on as an assistant at $75 a month. I didn't want that.

Weiner:

Especially when you have to eat. How about other people at Stanford? Did you come in contact with any experimental people like Hansen?

Oppenheimer:

Yes. I was in the lab with him, would go up and talk with him about what he was doing. He was doing radar work then, and he had his wife drive up and down the street, to see if he could detect her car. Bloch wanted to use neutrons to look at the structure of matter to some extent, and Staub was building a cyclotron, which wasn't very successful then.

Weiner:

Staub?

Oppenheimer:

Yes. There was another man there by the name of Bowes who was building a high pressure ultra-violet light source.

Weiner:

How about Webster?

Oppenheimer:

Well, he was chairman of the department. I did for the first time some teaching there. I taught optics lab. I also taught one of the lab sections of the undergraduate introductory course.

Weiner:

This was all for $75 a month. But there was no specific scientific work that you did that came out of that?

Oppenheimer:

No. I didn't get any results. I never even got the apparatus going.

Weiner:

Because you didn't take the time, you mean.

Oppenheimer:

Partly because I didn't take the time, partly because there were almost no resources there, funds for doing anything. And the whole business was — a transformer accelerator — that was very badly built, leaked and got hot in the wrong places. Bloch asked me to get it working, but the right thing to have done would have been just to have started over again. There were no funds for that.

Weiner:

During this period you were still going to New Mexico for the summers?

Oppenheimer:

Yes.

Weiner:

Did the character of those summers change? Were the visitors different? Was your involvement in it different? We could talk a little about the atmosphere and what it was like, since I've heard from some of the other people how important it was for them to drop by there. It would be nice if you would talk a little more about what life was like there.

Oppenheimer:

The dominant thing there really was horseback riding. I think we probably rode about a thousand miles a summer, and we'd take some of the trips up in the mountains overnight. Some of them would be to go up in the mountains and then drop down in the desert, stay at various little towns in the desert, just go around — we rode from there up into Colorado. We rode all around the Jemez Mountains. We rode down south, to the east side of the Sandia Mountains. We really got to know the country terribly well. When visitors would come, we'd take them out on little shorter trips. My brother would do physics with people occasionally, but not too much of the time. I was often there somewhat longer than he was. We did a lot of cooking, some fixing up of the house. My brother and I both had sort of interesting horses which we liked. I don't know what else to say about it.

Weiner:

How much of the time did you have visitors? Did you have lots of times by yourself?

Oppenheimer:

We had lots of times by ourselves.

Weiner:

It wasn't a houseful of visitors all the time.

Oppenheimer:

And not terribly many at one time. Four was the maximum, usually just one or two. Some people came back there after the year — I think Charlie was back there once.

Weiner:

People like Weisskopf would stop if they were passing through?

Oppenheimer:

Yes. He didn't like to ride horses. The Serbers came on. Got to know them very well. The times when my brother would bring his troupe down to Cal Tech for the spring semester were really enchanting — really brought a whole fresh life into the place. We got to know the Serbers quite well. We had a house together one year. In Pasadena. They came down from Berkeley with my brother.

Weiner:

They shared with you.

Oppenheimer:

We moved and rented a house. All together. Willis Lamb was there, and I don't remember when he was there — I think he must have come with my brother. I think so.

Weiner:

Phil Morrison was there —?

Oppenheimer:

— Schwinger, it seems to me — Schwinger may have come — I think he did, one year, but I'm not sure.

Weiner:

Schiff, I guess.

Oppenheimer:

Yes, Schiff.

Weiner:

And one year Furry was down anyway for some time.

Oppenheimer:

Bohr visited there one year.

Weiner:

Yes, '37. Well, I just wanted to catch the summer atmosphere too.

Oppenheimer:

What we'd do, we'd start off very early in the morning, and saddle up a horse, sometimes a pack horse, and start riding. Usually have some new place that we wanted to go, often where there was no trail, and we really knew the mountains, the upper Pecos, the surface of the whole mountain range. A few places where we wanted to go often, we'd cut a trail. We built a log cabin up in the wilderness area for one of the ladies, for Catherine Page. And there were wonderful flowers all the time. The place was very lush. Sometimes in the rainy season, it rained less at night and we'd start off at night.

Weiner:

How long would you be on these trips, several days?

Oppenheimer:

It would vary from an afternoon's trip to, I think the longest one was up into Colorado, took about eight days.

Weiner:

When you say we here, was generally the nucleus yourself and your brother?

Oppenheimer:

My brother and I and my friend Roger. Then of course Jackie after we got married. The first year when we went there, in addition to Roger, I had another friend from high school.

Weiner:

Did you give up the place finally?

Oppenheimer:

No, after the war my brother bought it, and they still have it, it's still there, belongs to his son and daughter. The son Peter uses it. The daughter has been on the water mostly, has a place in the Virgin Islands. During the evenings at Perro Caliente, with our friends the Uhlenbecks — we learned a new form of tiddlywinks; we'd do that and sit in front of the fire — and talk. A lot of it was during Prohibition, but there was always drinks available, home brew. My brother had an air of great specialness, almost everything — we had wild strawberries with Cointreau. When Uhlenbeck came, we always cooked Indonesian food, Elsa Uhlenbeck cooked it.

Weiner:

How did you get the ingredients for such things?

Oppenheimer:

She brought them with her. Very often he was quite tired, and it really revived him.

Weiner:

Was it generally his physical constitution, not very strong?

Oppenheimer:

No, he was always thin, but he was pretty wiry.

Weiner:

Tired emotionally, intellectually, because of his work.

Oppenheimer:

It was a very — it was a nice combination of primitiveness — we didn't have electricity, and had a pipe stuck in the spring for water, and a house that had plenty of rats in it, and slept out on the porch. It was wet and cold a lot of the time, and we spent a lot of it in the house — but it wasn't really that uncomfortable.

Weiner:

A fascinating environment.

Oppenheimer:

It was.

Weiner:

Let me then get back to this other thread — after Stanford, you would have gone out one way or another, and then I guess it was the war that determined for you what would come next?

Oppenheimer:

Yes. What happened there was, there was a little while when I looked for any old job and didn't find anything that I really liked. I could have gotten a job in a small company but then, the business of separating isotopes came up, and I guess I'd been over to Berkeley enough and talked with Lawrence, so that orbits and magnetic fields were simple for me, I started that

Weiner:

Did he ask you specifically to come and get involved in the project?

Oppenheimer:

Yes. But it had just started. When I got there we started by dismantling the old 37 inch, and used it for adapting the chamber, and set up another exhaust. It was a fairly hectic beginning. Then after Pearl Harbor, there was an increase in pace and sense of urgency.

Weiner:

Let me ask you something about earlier. During the period when you were at Stanford, there were joint colloquia with the Stanford people and the Berkeley groups.

Oppenheimer:

Yes.

Weiner:

Berkeley people. Do you recall any of those and participating in them?

Oppenheimer:

I didn't give any of them. I remember going to an awful lot of them.

Weiner:

Some would be at Berkeley, some at Stanford.

Oppenheimer:

At least I went to most of the ones at Stanford. Occasionally at Berkeley.

Weiner:

Well, getting back to the work — this invitation to join the group from Lawrence, it was on a very specific job and assignment.

Oppenheimer:

It was in charge of a group working on the calutron in the old 3711 magnet. I had first spent a few weeks on the crew of the 60" cyclotron.

Weiner:

Well, what about the politics? Was Lawrence annoyed in any way by your obvious visible politics?

Oppenheimer:

Well, I wasn't quite as active as I was before that in the 1930's, in '39. I didn't have any politics I wanted to do so much. I think he was quite aware of it, but as long as I wasn't doing anything to embarrass the lab, he didn't care.

Weiner:

Did that mean you moved to Berkeley?

Oppenheimer:

Yes. Well, we lived in Brisbane, and then moved to Berkeley. That went very well, and I worked pretty damned hard there all through, and slept relatively little. It was very interesting, in a sense, this business of starting with a tenth of a micro ampere and ending with 100 amperes at Oak Ridge. I spent some time at Westinghouse overseeing the manufacture of the calutron source units.

Weiner:

Westinghouse, where?

Oppenheimer:

Pittsburgh. They made the positive ion sources for Oak Ridge.

Weiner:

Did you stay, except for these trips, at Berkeley for the whole period, or were you at Oak Ridge? Were you at Los Alamos?

Oppenheimer:

I was at Berkeley until we had sort of frozen the design of the ion sources, then went to Westinghouse, while they were being build, then went to Oak Ridge and helped start up the alpha tracks, train people in fixing things, redesigning things that broke, and complained to General Groves and others about people and contractor companies... people who sort of slacked up on the job —

Weiner:

Let's take a break —

Oppenheimer:

— I worked on the engineering and the trial and error kind of thing that went on with the Calutron development, and got really quite close to Lawrence, saw a lot of him. He and I took a trip to Princeton to take a look at the work Bob Wilson was doing on isotope separation. We decided that Wilson's approach wasn't going to get any place, which was probably a good decision because Bob then went to Los Alamos.

Weiner:

Yes, and took Feynman and quite a number of other people with him. What was your impression of that group, how it appeared to you? Wilson has a good style — I'm just curious how the group was working, if you observed them while they were working.

Oppenheimer:

I observed the day to day operations and the spirit of the Princeton group was wonderful — we just spent a couple of days there — and I think the thing that disturbed me about what they were doing was connected with the trouble that we also had with the Calutron. As one pushed up the current in the ion source, the plasma started to oscillate. And these oscillations prevented the space charge neutralization of the beam. And the configuration of his ion source was so restricted that he couldn't do much about it. At least that was my impression. Bob was very enthusiastic but I think also recognized this difficulty. I don't remember much detail about how the group worked — that was all I saw it. But it was good. I had the impression from talking to enough people who observed him that it was very interesting.

Oppenheimer:

Just that brief visit made me a lifelong friend of Bob. So I went then and spent a good deal of time at Oak Ridge and I got to be a pretty good expediter, so just before the test in May or June of '45, I was asked to go to Los Alamos and help Ken Bainbridge with the test.

Weiner:

Oh, so you actually did transfer then to Los Alamos. Did you get to see your brother much during this whole period?

Oppenheimer:

Not much. He'd come to Berkeley once in a while, I saw a lot of him after I got to Los Alamos. There are a couple of things I could say about Oak Ridge, I guess. There's a lot to tell, but one in particular. When Lawrence — after things had sort of gotten started, Lawrence gave the non-science people without clearance, a sort of pep talk. One of the things he said in his pep talk was that "What you're doing here is very important. A hundred years from now, they may not remember that there was a war on now, but they will remember what you were doing." I'd gotten into all this development work and expediting and I remember one time Oliphant coming to me and saying, "Frank, you've got to stop this, you've got to be a physicist again." "Don't go on —” it was very good advice.

Weiner:

He said it during the war?

Oppenheimer:

That was just at the end, spring of '45. Just before I went to Los Alamos. But months later, after VJ day, while I was working with Gerald Zacharias on the business of seeing what to do next, with the design of the Bomb it was a question of redesigning the bomb so it would go into one of the B –- I don't know, B, what was the next B, 56? Then I suddenly realized, what the hell am I doing here? And went back to Berkeley. I think people wanted me to go other places but I wouldn't because I felt some sense of loyalty to Ernest or Berkeley.

Weiner:

By other places you mean different universities, regular physics department jobs.

Oppenheimer:

Yes. Right.

Weiner:

Were they proper offers? After all, you didn't have a position really.

Oppenheimer:

I think Zach's offer at MIT was a fairly solid offer. I don't know about the others.

Weiner:

Let me ask, back to Los Alamos, did you see the tests?

Oppenheimer:

Yes.

Weiner:

Where were you?

Oppenheimer:

At the nearest station, the five mile station, outside.

Weiner:

It would be interesting to get your description of what you saw, how you felt, — how other people reacted —

Oppenheimer:

Well, you know, it was at the end of this long rainy night, and we'd gone to the tower and inspected it, over and over again, stood around waiting and wondering what to do, and finally saw that it was clearing, and not much time left before the light. There was this great worry that somebody might have been left behind, or was too close, and all kinds of tensions started building up. Then I remember the countdown — this complete ignorance of what might happen, in the sense, not that something terrible would happen, with atmosphere ignition, because we were sure that wouldn't happen. I had done a calculation to find out if the cloud might hit an inversion, and not go up but spread out. My calculation showed that it would penetrate any conceivable inversion, and that seemed to work out all right, and it has in practice, too. But my calculation involved assumptions about mixing that might have been wrong. They've always gone up, not down. So although there weren't any terribly melodramatic worries, in the sense, there were many tensions and doubts and vague fears. And then despite all the advance training, somehow you just didn't expect the kind of explosion that actually happened. The flash, nobody looked at it directly. One had one's head to the ground and one's arms up around one's head. But the light of the first flash penetrated and came up from the ground through one's lids. When one first looked up, one saw the fireball, and then almost immediately afterwards, this unearthly hovering cloud, It was very bright and very purple and very awesome, and one still had the feeling, maybe it's going to drift over the area and engulf us. And all the time that this was happening, the thunder of the blast was bouncing back and forth on the cliffs and hills. The echoing went on and on, and — but I think the most terrifying thing was this really brilliant purple cloud, black with radio-active dust, that hung there, and you had no feeling of whether it would go up or would drift towards you. The fact that it worked — one knew immediately that it would work. It was really so very surprising that it worked. I guess some people may have believed it would, but there was no real assurance that it would, and the sense of something happening at that time that you could hardly believe would have happened. It's kind of remarkable that all — when you knew how careful the implosion had to be, that all the detonators had to go, that there couldn't be any asymmetry, that it actually did work was really a surprise. I don't think I had any melodramatic thoughts about ushering in a new era, at the moment.

Weiner:

Was it a feeling of accomplishment — you tried to make it work, here it is, it works?

Oppenheimer:

I don't think so. It was just more like, you know about supernova, but if you saw one some night, it's the realization that something that's possible actually happened. Ken Bainbridge and I, we were sort of geared up for disaster and we spent several days finding escape routes through the desert and making little maps so everybody could be evacuated. I'd gone off and set off smoke bombs on the cliffs above us to see what the winds were doing. So this whole notion of fallout was very imminent. But everything — it cleared up right away. But at first that cloud was so damned ominous. And the noise.

Weiner:

Where was your brother? Were you in contact with him during this?

Oppenheimer:

I think we were lying down next to each other.

Weiner:

Did you talk with him about reactions?

Oppenheimer:

I don't remember what we said, now.

Weiner:

Well, you know the statement about —

Oppenheimer:

— that we helped each other or something.

Weiner:

— the statement that's attributed to him. I wonder if in fact that was made? You heard it?

Oppenheimer:

I didn't hear it. I believe it was made. I don't know if it came to him on the spur of the moment or not.

Weiner:

Once that statement was made, was there any kind of a resonance of feeling that this sort of unleashed, in terms of the deeper implications of this?

Oppenheimer:

The whole thing was really right there on the surface for all of us. Little odd things. The night before the test, all the frogs in that area had gathered in a little pond by the camp and copulated and squawled all night long. There is a kind of funny significance that the only living thing around there, coming together — I mean, everything was full of the import. When I say I can't remember any deep thoughts, it was just… the whole thing was so full of import.

Weiner:

How long did you stay on after that? That's what you went there to expedite, and then how long did you stay on at Los Alamos?

Oppenheimer:

I believe I left sometime in September and went to Berkeley.

Weiner:

Were you aware of the Chicago petition?

Oppenheimer:

Yes.

Weiner:

What — how did you hear of it? What kinds of discussions took place at Los Alamos? Did you hear of it there?

Oppenheimer:

I think I heard of it first at Oak Ridge. When Smythe got a little group together at Oak Ridge, sometime during the winter or spring. We talked about what people thought should be done. I think most of the people that I talked with thought it should not be dropped on a population center, but it should be dropped.— where? It shouldn't be kept secret, it should be dropped somewhere, and some place, so not just the generals but also the Japanese people would know about it, and the world would know about it.

Weiner:

Dropped in Japan somewhere?

Oppenheimer:

But in an isolated area. It wasn't — I think the greatest danger, to me, seemed the notion that we would have this thing in our hip pocket and nobody would know about it. Probably that wouldn't have worked, because it turned out there was quite a lot of espionage. But that seemed like a terrible thing for us to have, in the background of all our negotiations, a secret like that. There was great disappointment that there was less openness about it at the Potsdam Conference. My brother especially thought that if things had been done right there, it would have really opened up the possibility of arms control, but Truman, by being casual about it at Potsdam, and using it in a way that probably had to do with keeping Russia out of China, we dreamed that, because this would be a qualitatively different kind of weapon, people might behave differently, — none of that happened.

Weiner:

Was that apparent at the time, or is this in retrospect?

Oppenheimer:

I don't think one knew how irrevocable, that it was irrevocable. I think one still had hopes. And I know that when my brother discussed it with Acheson, he indicated that he still had hopes. But it was clear by then it would be much harder, than it would have been right at the time of the test.

Weiner:

You were still then, involved in the follow-up of the project, and you went back to Berkeley with that in mind?

Oppenheimer:

No. I left Los Alamos — I was through with Manhattan District, and with any secret work with it or any other project.

Weiner:

Although when you went back to Berkeley, you were still Manhattan District because Berkeley still was for a couple of years after anyway. For example, you published the linear accelerator paper — it was a Manhattan District paper, their sponsorship.

Oppenheimer:

Yes. I guess they were sponsored by the AEC as soon as it came to be.

Weiner:

It was a transition, right.

Oppenheimer:

Let's see — when I went back to Berkeley, I worked on several things. I worked on new ion sources in magnetic fields, and was invited to go to Sweden to talk about them there because they were interested, but I couldn't get a passport. And then worked with Luis (Alvarez) on the accelerator. I also did the first particle physics experiment with the 184 inch. It was a simple experiment, which was sort of nice. I looked for and observed neutron to proton exchange reactions.

Weiner:

The passport — there's two possible reasons. One is because of your past politics; the other is your special knowledge, which may have made them reluctant to let anyone who had worked on the Los Alamos project out of the country. Which was it or was it a combination?

Oppenheimer:

I think it was a combination. I wrote a letter saying that I realized they might feel themselves vulnerable if they let me go, but that there was no rational reason for not letting me go, therefore I thought it was an injustice. And I got a letter back from the lady who was head of immigration that three separate agencies of the United States deemed it unwise to give me a passport. She didn't say which ones.

Weiner:

Was that the same lady who's figured so prominently since?

Oppenheimer:

This was in the early fifties. It was Mrs. Shipley.

Weiner:

There was another very vocal lady on these things, I've forgotten her name. What were your expectations in going back to Berkeley? What was your status when you went back?

Oppenheimer:

I was research associate and I hoped to be on the UC faculty — to start teaching. And I think it was probably because of the radical thing, which this didn't happen.

Weiner:

There was a period just before the war when the regents were talking about investigations of radicals on all the California campuses. I don't think the war changed very much in terms of their attitude.

Oppenheimer:

I don't think so.

Weiner:

As witness the loyalty oath business very soon after.

Oppenheimer:

I had quite a good time with those three postwar projects.

Weiner:

Let's talk about them if you like. Something I didn't ask — that is, fission itself. Were you at Stanford when the news of fission came?

Oppenheimer:

Yes. When was that?

Weiner:

I guess December '38, but the real American understanding was January of '39.

Oppenheimer:

Yes —

Weiner:

You would have been at Cal Tech.

Oppenheimer:

Wait a minute — January of '39? Cal Tech.

Weiner:

Do you recall anything about that?

Oppenheimer:

I think actually for some reason I was in Berkeley — so I heard a remnant of talk about it in Berkeley. I was probably up there for the holidays in January '39 — yes.

Weiner:

I saw a letter of Willie Fowler, about that time, discussing fission and a lot of things, and he mentioned that you and your wife were coming down with him. I think it was before you were officially at Stanford, sometime in '39, maybe making a trip of some sort. But were there any special conversations or discussions on the implications of this? What this would mean in terms of weapons or anything else?

Oppenheimer:

It's so hard to disentangle it. I think I remember discussions about, to what extent one should initiate secrecy, even at the very beginning. That might have been a later discussion, but my impression is that there were — there was some sort of talk about that right at the start.

Weiner:

Certainly by 1940, there was talk — censorship started a little later.

Oppenheimer:

Yes, but I think there was talk of it even as soon as it happened.

Weiner:

Getting back to this postwar period, in the discussions with people at Los Alamos or elsewhere, were you conscious of any re-evaluation of postwar physics, the way it's going to be, what the relationship with government would be, what kinds of problems people would be interested in?

Oppenheimer:

Very early on, there was the kind of discussion that was centered around the military versus non-military control, the May-Johnson bill. I did a lot of talking, giving talks, around, not so much about what physics would be like, but on the need for a new attitude towards war, the need for controls, not putting atomic energy in military hands.

Weiner:

Were you in any of the groups? There were a number of them, Alice Smith has written about them, the Los Alamos group —

Oppenheimer:

Yes?

Weiner:

— well, that was one. There were local groups. But basically were you involved in that?

Oppenheimer:

I was very much involved in that. I gave a talk in the fall of 1945, which is essentially not a very political talk but it was on the Calutron development. I'll show it to you.

Weiner:

Where was it given?

Oppenheimer:

At Berkeley Democratic Club. They sponsored it. Everyone wanted to hear about it — I talked to doctors' groups — teachers' groups, the officers' club at Mare Island. I have to look up the date, when did the Acheson-Lilienthal Report come out? In spring of '46, wasn't it, fairly fast?

Weiner:

I think so. This was a period of intense activity and lobbying in Washington. You weren't involved in the national on this, were you? You weren't on any national committees? You were a member of FAS? And then responded locally —

Oppenheimer:

Yes. Whenever there was an executive board meeting where I happened to be — I was always there — but I wasn't an official member.

Weiner:

It's interesting to ask about this change in your brother's career from being a professor of physics of some good reputation to a national and international figure. Was there any significant stress that he felt about this? Did you notice any significant change? Were these things that he thought about and talked about?

Oppenheimer:

I guess the kinds of arguments that we had, discussions, had to do with his assessment that if something was going to be done, decisively, by using this weapon to introduce a new era, it had to be done essentially by officialdom, that there wasn't time to educate the general public, and his feeling that officialdom would go along with him. It didn't. But he was also right — there wasn't time to educate the general public. Maybe — I'm not so sure. There was something wrong with the way we went about using the fear tactic of educating, the current fear of radiation is so deep and national. Jadde is going to compile some statistics which she has herself [on sale at the Exploratorium of] SCIENTIFIC AMERICAN reprints. She has one on mutagenic effects of radiation and one on radiocarbon dating, and she may sell a dozen on such obscure things as reprints about spark chambers but she's only sold two or three on those two topics involving radioactivity. People have sublimated the fear of radioactivity to all manner of other fears.

Weiner:

So the issues you don't feel were ones that somehow grabbed people, somehow they didn't respond to them the way they were being raised by scientists.

Oppenheimer:

No. They did get people very scared of attack. That's all. But the issues which involved nationalism and finding alternatives for international conflict didn't come across at all. People still believe that the best way to influence what happens, if you really believe in it, is to fight for it, and I can see why, because all of literature and history and all morality has told people that. Then suddenly we say, "Well, there's no way you can fight for what you believe in anymore." It wasn't enough.

Weiner:

There were very few precedents they could refer to.

Oppenheimer:

Yes.

Weiner:

About the war experiences and your brother's role, did this in any way change his relationship with you, with friends, with students and colleagues?

Oppenheimer:

I think it did. I think that — well, again, he was a very popular hero among the young people, and his reliance on maneuvering in Washington, they felt let them down, and I think it wasn't so much they were angry with him that they were disappointed that he didn't help them, more. I think that was quite widespread. It would have been very nice if he could have been the popular leader, but there's not much evidence that he could have gone much further if he had.

Weiner:

The public leader in those struggles, for example the FAS struggles and other things.

Oppenheimer:

Yes.

Weiner:

Well, it's not clear that he believed in all the points that were being made. It's not just a question of tactics; it's a question of the program. It's not clear that he would have agreed with it all.

Oppenheimer:

Those things are so interwoven that in order to follow the course that he was following, he had to be congenial with the people he was working with, who did believe that if we didn't arm right away, Russia would walk over Europe. So the tactics and the beliefs are very interwoven.

Weiner:

How about changes you might have perceived in him, in terms of his relationship with you, for example, his personal style, personal life, psychological state?

Oppenheimer:

I think that fluctuated. I think when he was first getting involved, we were sort of estranged a little bit, but by — even well before his case-came up, we were talking the same language again.

Weiner:

How about the ranch, were you back there after the war? Did that ever blossom as it had before the war?

Oppenheimer:

No. I don't think we spent another summer together there after the war. We did go to New Mexico one year, '47 I think it was, but it was with Bob Wilson and we rented another place. I doubt if Jane would have wanted to have her family in such a primitive place, so we rented a place in the Nambe Valley.

Weiner:

This gets us back to Berkeley. How did you become involved in the — you mentioned these three projects in the postwar period. It was only a period of two years or less. And the one paper that I know coming out of it — well, the first paper, there were two. One is the drift tubes for the linear proton accelerator, Johnston and Richman, this was a design paper I gather, what the design of the tube might accomplish, and it was Manhattan District sponsorship because that's what the lab was still under. You come back after the Los Alamos experience. You'd been to Berkeley on a war project. Now you're back to Berkeley, with an official appointment as a research associate, was it?

Oppenheimer:

Yes.

Weiner:

And that meant working in the Radiation Laboratory?

Oppenheimer:

Yes.

Weiner:

No connection with the physics department as such?

Oppenheimer:

No. I think the first things I did were working on the ion sources. There should be a paper on that.

Weiner:

There's one later. Let me get the page — here it is — it's '49.

Oppenheimer:

I got intrigued with Luis' accelerator scheme [which] was really elegant; I mean the one of putting a lot of cavities together and then removing the walls.

Weiner:

Had you known about this at Los Alamos when you'd started thinking about it?

Oppenheimer:

No, I learned about it when I got back to Berkeley. I don't know whether he asked me to work for him, or Lawrence asked me to work for him, or I — it's another one of these things where I don't remember having made a decision. I guess the first thing I did was make a 10 centimeter wave length model, and that's what the paper with Richman was about. To test out the basic idea and see if the thing would oscillate as a whole, how critical the tuning would be — it turned out one could tune the cavity quite simply. They eventually had other ways of tuning it, but it turned out you could tune it very simply just by moving the end drift tube — and the first model was built that way without lowering the Q of the cavity. Then I designed an ionization chamber, and talked about it with Luis, and he suggested making a differential ionization chamber. I had it built, and I was about to leave for Minnesota, just when the 184 inch got going, and did something I really liked because it was — there was all the talk of the meson as an exchange particle, but nobody had ever seen an exchange reaction, and you could tell, by putting in some paraffin and looking at the energy spectrum of the recoil protons — it was very clear that there was a strong forward peak due to the exchange reaction.

Weiner:

You weren't involved in, other than this thing with Luis Alvarez of the linear proton accelerator, you weren't involved in the 184 inch.

Oppenheimer:

I was not involved in the design or the building of it.

Weiner:

Now, this research associateship would have started in '45 and gone through '47. When it became clear to you that it wasn't going to lead to a faculty position, which is what you wanted, then how was it that the Minnesota offer came through? Did you let it be known you were available?

Oppenheimer:

No, Buchta, the chairman of the physics department at Minnesota, came by looking for people, and talked to Ed Lofgren and to me, and I liked Lofgren very much and I was intrigued with the idea of the cosmic ray research at that altitude. The job was also to be a teaching position.

Oppenheimer:

Well, Buchta came by and said General Mills was making great big balloons that would go up to 100,000 feet with 80 pounds, and it looked like a good opportunity to do some cosmic ray work, and also elementary particle physics. And I think Tate was the person then who wrote the grant to ONR and who was officially the administrator. He didn't take part in the research.

Weiner:

You went for the cosmic ray work then?

Weiner:

Were those faculty positions for cosmic ray work created with ONR funds? Were new positions created?

Oppenheimer:

I think they were university positions, but some fairly large fraction of the salary probably came from ONR. That was a paradoxical development, the ONR, because during those years it was the only enlightened source of research funds even though it came from the military which we were all in principle skeptical of.

Weiner:

Yes, I've been getting into this. I talked years ago with Charlie Lauritsen about it, who was instrumental there, but also with people like Bob Marshak to see how it could affect Rochester, and then with Willie Fowler the other day, to talk about the effect at Cal Tech, and we dug out some of the earlier proposals, to see what ONR was doing — it was quite interesting.

Oppenheimer:

Well, the guy who was so good there was a man by the name of Urner Lidell, who for my money has gone completely to pieces in recent years, but he was just marvelous at that time — at ONR.

Weiner:

Someone should do a history; someone now is digging into the early part of it. I don't know how extensively it will go. It's more a political science study.

Oppenheimer:

It reminds me always of another story, which is not necessarily for the tape. When we were ranching, there was a soil conservation man who was sent from the federal government, to the soil conservation district. He noticed that all the ranchers there were flooding their meadows and just letting them stay soaked, and this practice gave rise to the growth of sedges, which have very little nutrition. He convinced us to drain the meadows and irrigate sensibly. We did this, and built big drain ditches, and one day he came up and we wandered around the meadow, and then looked down, in the drain ditch, and there in the bottom of the drain ditch, just sitting in constant water, was the most beautiful stand of timothy hay that you could imagine. He said, "Nature sure makes a liar out of you, doesn't she?" Well, this ONR thing —

Weiner:

Great. Well, when the offer came from Minnesota then, that's fine, but had you thought of cosmic rays before? You had been exposed certainly at the Cavendish, then the people in Florence, and very definitely got into that and you were at Cal Tech where it was a tradition, but you'd never expressed an interest — this was appealing to you?

Oppenheimer:

Well, there were so many components to it — the technical component, plus the fact that one didn't at that time have available at all any really high energy, fairly pure proton beams, so it looked like one might learn — that's why we decided to fly a cloud chamber, because one really thought one might see something about particle physics. It turned out we didn't do much nuclear physics.

Weiner:

But you discovered some heavy nuclei.

Oppenheimer:

Yes, with some photographic emulsions, they were just sort of tacked on to the first flight. All of these things were sort of fun. When the plates got developed, Phyllis Freier brought them in and I looked at them, and they were really full of things. And I found one slightly heavier track, and followed it, and just kept going and kept going. I think it was an alpha particle and it could well have been a secondary, but just seeing this, suggested that maybe all kinds of nuclei were coming in. And I told Phyllis Freier to go look for them, and she did. She came back with the big ion tracks the next day. It seems somebody else had seen these great — they looked almost like fissures in the photographic plate — and thought they were some sort of static discharge between the plates. I liked this process of discovery because when I first looked at the alpha particle, it probably had nothing to do with heavy cosmic rays. (Although it could have.) But seeing these as something just slightly heavier than the proton ionization suggested this other thing, whereas people who saw the heavy fissure first, missed the point. So much discovery happens through small steps from what is known to what is new.

Weiner:

Well, that's very interesting. Let's get you into this story. You took the position. You mentioned General Mills was building this balloon. What on earth for?

Oppenheimer:

I don't know, that was a little bit vague.

Weiner:

Was there some other application besides the cosmic ray thing?

Oppenheimer:

I think they must have thought there would be, and there may have been. I don't think the military actually did use them, but maybe they did. But very little was known about the upper atmosphere. For example, we had to make a test flight to know what temperature an aluminum sphere would get to at 100,000 feet. So I think probably there was some military or at least aeronautic interest in having a considerable payload brought up to a great height.

Weiner:

At any rate, they were committed to this. But they weren't building them for the Minnesota cosmic ray —?

Oppenheimer:

No, they were building them, and then I think were glad to have an excuse, and someone to fly them, because they didn't — I think we flew all the ones that they built first.

Weiner:

Well, who in the group had had experience in cosmic rays, or was this completely started from scratch in Minnesota?

Oppenheimer:

It was completely started from scratch. Nobody there had done any work. I'd done work with counters, and a little, quite a lot of exposure to cloud chambers at Cal Tech. Ed Lofgren was a great instrument maker. But he hadn't done any work with cosmic rays.

Weiner:

And Phyllis Freier was a graduate student. Was there a particular physics problem in mind, which you were going to look for very high energy particles?

Oppenheimer:

Yes, we built a cloud chamber with lead plates in it, so we could distinguish mesons from electrons, from the showers. The simplest thing to look for was meson production multiplicity.

Weiner:

Were you following, once you got there, the work that was coming out of Europe, for example, the Italian work, work by Conversi and Piccioni and other people, a whole tradition which had been kept alive and had flourished during the war, which is another story but fascinating. Also the work that was coming out of Bristol.

Oppenheimer:

Yes. Some of that had preceded the work we were doing. But nobody had done much with multiplicity, in the past. But then of course after our first flight, we kept flying the cloud chamber, but we got sidetracked, and thought we saw one interesting phenomenon that turned out to be trivial — spray of particles of fairly low energy which turned out just to be cosmic rays going lengthwise through the lead plates. But I gave a paper on that. That turned out to be nothing new. But at first the "spray" seemed very mysterious.

Weiner:

Which paper was that?

Oppenheimer:

That was at the Echo Lake conference in June of 1949.

Weiner:

I don't see it published.

Oppenheimer:

Yes, "Wide Angle Sprays."

Weiner:

Paper No. 16. Well, the one paper, the first paper that comes out of the Minnesota work with Phyllis Freier, Lofgren, and then the other with Bernard Peters and Bradt from Rochester —

Oppenheimer:

— yes, the Rochester group.

Weiner:

How was it that this collaboration started?

Oppenheimer:

They heard we were going to fly. They asked whether they could collaborate with us. And so they came out, with the first balloon, and they took half of the photographic plates back to Rochester, we kept others.

Weiner:

I see. You were using Ilford emulsions, weren't you?

Oppenheimer:

Yes.

Weiner:

Had you been in touch with Powell's group regarding the types of photographic plates that you used?

Oppenheimer:

I don't think so; I don't think we went through Powell. I think we did it directly from Ilford, who really knew about it.

Weiner:

By that time you could actually get them from Ilford. I see. Now, did you know Peters when he was at Berkeley?

Oppenheimer:

Yes. I'd known him.

Weiner:

There was a particularly productive period, looking at the bibliography. A number of papers came out. You were getting some very interesting results.

Oppenheimer:

Yes. We made the flights in Minnesota, and then the Navy let us ride on an aircraft carrier so we could do some work in the southern latitudes.

Weiner:

Oh, where did you go on that?

Oppenheimer:

On the south coast of Cuba. I got to know the hill people on the Sierra Maestra.

Weiner:

In one of the papers, the one on the heavy components of the primary cosmic rays, you make a judgment that the results have relevance to astrophysics because of the link of the hydrogen helium ratio which involves burning processes in the stars. Now —

Oppenheimer:

That has to do with the initial acceleration, whether — I forget just how it went — I think it was, if it was the kind of kinetic acceleration which came about from a Fermi-type collision, you know, with gaseous cloud, then the energy spectrum should be the same as protons. But if it was a betatron acceleration, then the energy spectrum would be different, because of the different charge to mass ratio.

Weiner:

The interest in the astrophysics thing, had you been in touch with people who were concerned with this? For example, at Cal Tech, this is what they were now working on, Charlie Lauritsen and —

Oppenheimer:

— people that we saw and talked about this with — I talked quite a lot with Teller of Chicago and Critchfield, who was at Minnesota. Teller was always full of ideas on this sort of thing. I don't know which of the two it came from but it might have well come from him.

Weiner:

Well, of course, you didn't do this one with Bradt and Peters but they were involved in the same kind of thing, because Marshak was concerned with star energy problems also or had been earlier.

Oppenheimer:

Yes. I don't think this had directly to do with hydrogen, with stellar energy. I think it had to do with —

Weiner:

— well, the statement made specifically at the end of the paper was that this was linked with astrophysics because of the hydrogen-helium ratio.

Oppenheimer:

Yes. OK. But it had to do with, more with the way they were linked indirectly because of the acceleration process. If the acceleration process was in one way, then if we got a different hydrogen-helium ratio than one sees in the sun, for example, it would mean that the actual composition of the universe had a different composition, whereas if the acceleration occurred through the betatron process, one could account for the different ratio just by the acceleration.

Weiner:

I see. Now, when all this work was being done, it was just the time when Powell came out with the discovery of the pion, the Powell group.

Oppenheimer:

It was a little after that.

Weiner:

Well, yes, work was '47 actually and publication, I don't know the exact date of publication but —

Oppenheimer:

That must have been in the spring of '47, about that time.

Weiner:

And your work in '48 —

Oppenheimer:

— was after that. We knew about pions.

Weiner:

Right, and what was the impact on your own work? First of all, it seems to me that a couple of things happened. One, was that Powell's group, coming up with a discovery which was really fundamental to theory at the time, emphasized the importance of cosmic ray phenomena once again for studies of very high energy particles and so forth. Secondly, it demonstrated the validity of the photographic emulsion technique as a precise tool. I just wondered whether in your budding cosmic ray group in Minnesota, these things made you focus in one direction or another or gave strength. How did it influence what you were doing?

Oppenheimer:

Well, it certainly influenced the fact that we hung some photographic emulsions on our cloud chambers.

Weiner:

Yes, right, to start with, but that was the result of seeing what had come out of Bristol. You had not done that before.

Oppenheimer:

I mean, that first flight must have been a year after, must have been in '48.

Weiner:

The publication was '48.

Oppenheimer:

The publication was very shortly after the first flight. I think we knew all about what Powell had been doing. I think my experiment at Berkeley had been after Powell's announcement of the pion. Looking at the exchange force.

Weiner:

The experiment at Berkeley?

Oppenheimer:

Well, it wasn't published. It was a laboratory report.

Weiner:

Was anyone from your group in touch with the Powell people by correspondence?

Oppenheimer:

I don't think so. No.

Weiner:

Any conferences where you came in touch with them? Did any of you go to any of those conferences where they were?

Oppenheimer:

We didn't go abroad. Did any of them come?

Weiner:

No, Powell didn't come, Occhialini didn't come.

Oppenheimer:

I couldn't go abroad.

Weiner:

They couldn't go, you couldn't go — that's great for communication.

Oppenheimer:

I don't think we had any direct communication. There were other people who were experts, who knew something about how to develop the plates. I'm just not clear. We did have instructions on how to develop the plates, how to cool them down, and whether we got those directly from Ilford or whether Phyllis had written Powell or not, I just don't remember.

Weiner:

I met her, when I gave a colloquium talk in Minnesota —

Oppenheimer:

She was my first graduate student, a real treasure.

Weiner:

By this time, or shortly after, AEC it also mentioned as being involved in the funding, so I guess they were — AEC and ONR both, for the balloon funds.

Oppenheimer:

In here?

Weiner:

In the Minnesota period.

Oppenheimer:

I'd forgotten that.

Weiner:

Well, they're mentioned on the one paper anyway.

Oppenheimer:

I wonder if they helped with the Caribbean flight? Could be.

Weiner:

How was the group oriented? Was there any kind of structure of the group? Seems to me there were lots of things to do. Was there a division of labor, someone taking a coordinating role, other people being assigned to developing plates, scanning them and so forth?

Oppenheimer:

Yes, Phyllis was in charge of developing and set up for scanning. Ed Lofgren, Ed Neg and I divided up some of the things that we had to do for the cloud chamber, to develop the cloud chamber, develop the sphere; I think this was pretty joint. I remember going to the company that built the sphere and I think Ed Lofgren looked into the things like lights and I was especially interested in the gas supply. We did take on specific tasks. I don't really know who was in charge of the group.

Weiner:

What was your faculty rank?

Oppenheimer:

Assistant professor. That's what we all were. I had some coordinating role, but in the way we worked, it was very — with only three people, we didn't need much structure.

Weiner:

Phyllis Freier was a student.

Oppenheimer:

Right.

Weiner:

Who was responsible?

Oppenheimer:

Tate was responsible for the grant.

Weiner:

Was there any theorist there who was —?

Oppenheimer:

Critchfield. We tried to interest some of the other people in the department. I've forgotten his name. But he found it [high energy physics] too messy — he was very precise.

Weiner:

At Minnesota?

Oppenheimer:

Then, some of the theoretical work was done at Rochester. I think they did the thin-down calculations — that is, the reduction ionization as the particles capture electrons as they slow up, the tracks get thinner and thinner, and I think the Rochester group calculated the thindown length as a function of Z. The problem always was to try and identify what the charge of the primary particle was. One way was to adulterate it, and I think Critchfield probably did that. The other was through this thindown.

Weiner:

That was done at Rochester. Well, if you had to review the work that was done there, what would you say were the most important results of it during the period in which you were involved? I have a series of papers here, but it's hard to say what your own estimate would be.

Oppenheimer:

The important thing was to discover that, in addition to protons, that all nuclei were components of cosmic rays. Which gave one another tool for their origin, which I guess should be obvious. I mean, it's one of those things that nobody's really ever talked about.

Weiner:

You were saying that it should have been obvious.

Oppenheimer:

Yes. So in a sense it was something that I think almost seems trivial, yet was really very exciting, to find it, and it proved a fairly useful tool, both to study acceleration mechanism, and the spallation processes. That is, if one finds isotopes in very unusual abundance, it's probably because they've been fragmented, which tells you something about the path length of travel in the galaxy. And as another tool for identifying the composition of the galaxy. It didn't lead to much new nuclear physics.

Weiner:

That's what I was getting at, it didn't go in that direction, but rather to astrophysics and cosmic rays per se, the origins — which is again closely relevant to astrophysics. Well then let me continue on this, on the teaching that you were doing at Minnesota, in addition to the research we've been discussing. What kind of teaching responsibilities did you have?

Oppenheimer:

I taught mostly lower division physics, and one graduate course. I've forgotten the text. I think I used quite a few texts. I used Compton and Allison in one part of it and Herzberg Atomic Spectra in another part of the course on atomic and nuclear physics at a graduate level. I did quite a lot of lecturing in the general physics course. I had a good time. I started up a journal club when I was there. When I first went to Minnesota, it was the first time I realized the kind of thing the FBI was doing. Before I got there, they'd been to the chairman of the department and asked if I'd arrived yet. Buchta said, "I don't even know if he's left yet," and they said, "Oh yes, he's left." Then once or twice they came around to just ask graduate students and people what was I doing at Journal Club, what kind of thing did we talk about? None of them had to do with information gathering; it was just to tell people to be leery of me.

Weiner:

Did they, students and others, tell you this was going on?

Oppenheimer:

Yes.

Weiner:

What was their response to it?

Oppenheimer:

Oh, I don't know, the people who told me about it obviously weren't made suspicious by it, but whether other people were — same kind of thing happened when we went to the ranch. We moved in there, and the FBI came around not only to talk to us but to the people in the little town and on neighboring farms, and said, "Is he doing any experiments?" They would ask people, "Does he have any radio equipment?" The people would say, "No, I haven't seen anything." They'd say, "Well, have you been in all the buildings?" Our ranch had had a granary, a barn, a chicken house, a potato cellar, a tool shed, etc. Nobody had been in all the buildings.

Weiner:

When did they do this?

Oppenheimer:

That was in 1949.

Weiner:

This was not the same ranch?

Oppenheimer:

No, this is the one we moved to after I got fired from Minnesota. And the people in Archuleta county really told the FBI to go to hell, said, "They're good neighbors." All except one woman who thought maybe we had something up in the attic, because you had to get to the ladder in the attic, and when she wanted to get something, we said was stored up there and she said, "I'll get it," and instead of asking her to go up the ladder I said, "No, I'll get it." The fact that I wouldn't let her go up that way meant to her that there was something secret up there. Only one out of the whole county that I know about.

Weiner:

How did you find that out, by the way, from her?

Oppenheimer:

She told somebody who then told us.

Weiner:

Let's talk about how this apparently pleasant and productive; normal physics work at Minnesota came to an end. What was the first inkling? You're telling me they were inklings, because of FBI inquiries and provocations, but was there any — your appointment was not a tenured appointment?

Oppenheimer:

It was not a tenured appointment, although a tenured appointment had been approved, before I left, for the next year. I was to be appointed to a tenured associate professor.

Weiner:

But it had not gone into effect yet.

Oppenheimer:

It had not gone into effect.

Weiner:

How did it come up? I don't know how the story unfolded.

Oppenheimer:

Well, during the first summer, that is the summer of 1947, my wife and John Williams' wife were staying up at a little resort during the summer and I was teaching summer school. I got up to this lake one night around 12:30, and got a call. I was asked to call back to Washington. I called the number and it was the TIMES HERALD saying they were publishing a story about how I'd been a Communist in the late '30's. The story was full of all other kinds of allegations that were false. The pre-war party membership was the only true thing in it. They asked me for a statement, and I simply said the whole thing was false, which was stupid of me to do. I should have just said nothing. They then came out with a great big spread the next day, about the fact that I'd been a Communist, which anybody could have found out, it was quite known. But then they said I visited with prominent Communists in Mexico when I took a trip after the war. Well, I visited the head of the physics department, paid my respects, and one other teacher who happened to be there. I didn't know if either one of them was a Communist or not, at that time or later. This was the kind of thing. Well, that sort of set the stage. Then the university asked me for comment, and I told them I'd have to say the same thing to them that I'd said to the paper, and they asked me to write it out. I had a lawyer write it out — which again, I should have just said "No comment." The university really put pressure on me though, time after time, saying "We can't keep you here unless you make a statement." I didn't see any point in making one statement to a public university and another statement to the public press. I could not have asked the university to keep my statement a secret, that wouldn't have worked. So they did this, I think, sort of to have me on the spot. So that when two years later I was subpoenaed to the Un-American Activities Committee, in the spring of '49, and told them that I had been a Communist, the university fired me, not because I'd been a Communist but on the grounds that I'd lied to them.

Weiner:

But there was no political issue, just a question of —

Oppenheimer:

— that they got out of it neatly.

Weiner:

How did the first newspaper story come about? Was this something that was stimulated by HUAC?

Oppenheimer:

I suspect it may have been in the beginning some sort of campaign to get my brother.

Weiner:

Did you sense at the time that it might have been? Did he sense that?

Oppenheimer:

We didn't say that to each other. Whether he sensed it or not, I don't know. It was also a time of great hysteria, so that it might have been completely just a good story.

Weiner:

In '47 —

Oppenheimer:

It was a little early for that.

Weiner:

That's when they got Shapiley [before HUACI just about that time — so it wasn't too early for them.

Oppenheimer:

There were other physicists too. I mean, Dave Bohm had been before them. So the witch hunt at that time was going on. I think I did the right thing earlier — I mean, I should have just said no comment, I suppose, but I'd just been through a long — I'd just given a talk to, I think it was the American Association of University Women, on honesty, and part of the thesis of my talk was that there was really no difference between withholding information and outright lying, so when they confronted me, I really found myself in a spot intellectually.

Weiner:

I described this as a productive, pleasant period, but apparently it started off with this kind of a cloud, which for the first time was a threat. It must have been a period of great apprehension.

Oppenheimer:

I just ignored it. I mean, I didn't ignore it when it first came out. About a week after the story came out, I got a call from a newspaper reporter. I was in my house alone at night, and when I answered, the reporter said, "Oh, are you there?" I said, "Sure," and he said, "We heard a rumor you'd been arrested." I really reacted. I locked all the doors and turned all the lights off and went to bed. But then it really didn't come up again, although I thought it might, but it didn't affect the work or the teaching or the relationships with others.

Weiner:

What was the response of the university to the firing? Was there any kind of protest on the part of the faculty?

Oppenheimer:

Some. Almost all of the graduate students. But nothing that made any difference. Buchta himself tried to do something. But there was a very concerted campaign against me by the FBI, because shortly after we moved to the ranch, people at Seattle, people at Chicago, people at Cornell all said, "The department wants you here, we've talked to the president, they would like to have you come," — and these things went on, but at the end of a month or so later, I'd get a letter saying it isn't going to work. And then the FBI would come to see us at the ranch. What we did when we were at the Un-American Activities Committee was to tell all about ourselves but refuse to answer questions about any other people we knew. But the FBI kept coming around asking us about other people and we still didn't want to talk about them, partly because we didn't know very much for sure, but partly because there was no point in getting other people who hadn't done anything wrong in trouble. And the FBI sort of intimated we'd be on the blacklist. They once specifically said, "Don't You want to get a job in a university? If you do, you have to cooperate with — It was just out and out, you know. This gradually sort of evaporated. Finally in 1959, I was invited, because I'd taught the PSSC course in Pagosa Springs high school, I was invited to help run a summer institute on it at Boulder. This temporary summer job got me up there and I got to talk with people, got a job as a research assistant with Bill Rense for a year or so. Lately I got to be an assistant and then associate professor and finally, full professor.

Weiner:

In this ten year period, how would you describe it? Did you withdraw? Was it a long withdrawal or an enforced withdrawal?

Oppenheimer:

It was enforced in some ways. There was no possibility of getting a university job. I probably could have gotten an industrial job.

Weiner:

In other words, conditions were such that no university or academic institution would take a chance on you?

Oppenheimer:

That's right. The departments and the, even the staff seemed to, but apparently [at] some level, somebody jot to them.

Weiner:

The grants…

Oppenheimer:

Yes.

Session I | Session II