The Manhattan Project

Carl D. Anderson's Interview

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Carl D. Anderson was a physicist who won a Nobel Prize for the discovery of the positron. He studied and taught at the California Institute of Technology (Caltech), where he took a class with a young professor named J. Robert Oppenheimer. In this interview, he discusses his impressions of Oppenheimer, including Oppenheimer’s early struggles as a teacher. Anderson describes the research that was going on at Caltech during the 1930s, including the groundwork that went into his Nobel-winning discovery. He also details why he turned down a role on the Manhattan Project, and the work he did on rockets during World War II instead.
Manhattan Project Location(s): 
Date of Interview: 
March 31, 1983
Location of the Interview: 

Martin Sherwin: This is an interview with Professor Carl Anderson at his home in Pasadena, California, March 31, 1983. This is Martin Sherwin. You first met him [J. Robert Oppenheimer]—­

Carl Anderson: In the summer of 1926, I was an undergraduate, and Caltech had a travel prize. And for a junior student, ‘26 was the first year they had enough money to send two people. So another fellow and I went. The plan was to spend six months anywhere: Asia, Africa. We chose Europe. No project, no duties. We were briefed on what to see: the architecture and galleries and so on.

There was an American Students Week that we learned about when we were on our way to Holland. We read in the local newspapers that there was an American Students Week at the University of Leiden. It was on our way, so we went there. There were not very many students there, something like eight or ten. But Oppie was there. He was already in Europe, I think, and decided to go to Leiden. And [Hendrik] Lorentz spent a great deal of his time there with the students. So it was a great thing to sit down and listen to him talk. I was a junior.

Sherwin: A junior at Caltech [California Institute of Technology]?

Anderson: At Caltech.

Sherwin: Physics major?

Anderson: Physics major. I started out in electrical engineering, but I learned there was such a thing as physics at Caltech, so I switched.  

Sherwin: So you got to talk to Oppenheimer?

Anderson: Not very much. We met on a boat – it must be a sea or a big lake – near Leiden on a sailboat. It was a very windy day and the boat was tipping thirty degrees or so. But I did not really get to know him then, just met him. And there were programs arranged for the students. I did not really talk to him or get acquainted.

Sherwin: That was the first time. And then after that?

Anderson: Well, he spent one term at Caltech when I was a graduate student and two terms, or about two-thirds of the year, at [the University of California], Berkeley. He would come down with an entourage of students who followed him from Caltech to Berkeley or wherever he went. I do remember signing up for a quantum mechanics course that he was scheduled to teach. So I attended that on the first day. There must have been about forty people in the room. It was some faculty and graduate students, and, I think, graduate students from other departments, chemists. It was a crowded room.

I learned later that that first day he was reviewing the Hamiltonian form of classical mechanics, but I did not know it then. I did not understand at all what he was talking about. He turned out, in later years, to be one of the most eloquent speakers I think you could find among scientists. But in these days, I would say he was a very poor teacher: he faced the blackboard, and talked in a very low intensity. You could hardly hear what he was saying. He paced back and forth, and would write some squiggles on the board wherever he happened to be, so the board was just a random collection of unintelligible things.

I realized that I was not getting anything out of the course. I had not had the preparation, for one thing. So I saw him in his office and told him that I was not prepared for that and would have to drop it. He pleaded with me not to drop it, and finally admitted that I was the last student in the course. The other people had already dropped out. And he wanted an official course at Caltech, so he assured me that everything would be all right at the end of the term. So I stayed registered.

I did not attend all the classes, but I would once in a while. There were still the forty people. The room was crowded all through the term. And at the end of the term he asked me—I am sure he knew—what was the highest grade and the lowest grade at Caltech. For a moment I thought of inverting the order, but did not, and I got an ‘A’ in the course.

Sherwin: Now do you know for a fact that everybody had dropped the course and you were the only one?

Anderson: Well that is what he told me, and I do not know how many people were registered for it. There were many people who were not students and were just visiting.

Sherwin: And they stayed with it.

Anderson: They stayed with it, yes.

Sherwin: Now this was the first time he came to Caltech.

Anderson: Well, I am not sure. This was I guess around ‘28 or ‘29.

Sherwin: It must be ’29, and that would be the first time.

Anderson: Because I got my degree in 1930. It must have been ‘29.

Sherwin: So it was the first time. That is a very interesting story. When you went to approach him, was that after a week of classes?

Anderson: Well, it might have been longer than that. I guess I was slower than the other people in doing this. I would guess something like a week or maybe ten days.

Sherwin: Did you have any idea in that period of time, anything that he was talking about?

Anderson: No.

Sherwin: Did anybody? Did you talk to someone and say—

Anderson: Well, apparently some people did because they stayed on. Though I do not remember checking up on it, or asking other people whether they were learning anything or not. I assumed they were, or they would not have stayed there.

Then another incident, which was about the same time, or it might have been a year or so later: Oppie was going to give a series of evening lectures. Not a course—a seminar, but not officially taken for credit. On the Dirac theory. This probably was about 1930. He was to talk for two hours in the evening, maybe three times a week or so, in the chemistry seminar room. So I went there. I cannot remember who was there. I do not think there were more than twelve people or so. But Richard Tolman, you know him, of course—

Sherwin: Yes, I know who he was.

Anderson: —was there. Oppie talked for two hours and I did not know what he was talking about. Richard Tolman, who was a professor of chemistry and physics at Caltech, was a quite good theoretical physicist. He has even written books on statistical mechanics and relativity, so he was certainly a well-established and brilliant guy. He got up at the end of the two hours and said, “Robert” – he always called Oppie “Robert” – “I didn’t understand a damn thing you said tonight except—.” And then Tolman went up to the blackboard and wrote down an equation.

Oppie said, “That’s wrong.” There was never a second meeting of this evening course of lectures.

Sherwin: That was it. Well, he still, in spite of being so incomprehensible, kept coming back, and continued to make an impression in some way. What was it?

Anderson: Well, his students, of course, worshipped him, and they were mostly people from Berkeley, because that is where he spent most of his time. There is no question that he was extremely successful in training a large number of theoretical physicists. Many of them became first-rate people. But these were the very early days. I think he changed, because in later years, as I said, he was one of the most eloquent lecturers you could hope to find.

See, I thought of something and I forgot it now.

Sherwin: How long did you stay at Caltech after you got your degree?

Anderson: Forever.

Sherwin: You just stayed right on—

Anderson: Yeah.

Sherwin: —as assistant professor. You knew him throughout the 1930s then.

Anderson: Yes.

Sherwin: I see. Well, can you continue to recall incidents? What were you working on at the time?

Anderson: As a graduate student?

Sherwin: What was your dissertation on, and then what did you do immediate post-dissertation?

Anderson: As a graduate student [Robert] Millikan assigned me the job of taking over what another fellow had been doing for his thesis work: using a cloud chamber for studying the space distribution of x-ray photoelectrons. So that is what I did for my thesis.

Sherwin: Did [Willie] Fowler do something like that?

Anderson: He was working with Charlie Lauritsen, who had the million-volt x-ray tube.

Sherwin: Yeah.

Anderson: After [John] Cockcroft and [Ernest] Walton [succeeded in disintegrating atomic nuclei], [H. Richard] Dick Crane, who was there as a research fellow, put a hydrogen ion generator in the thing and one afternoon, they had a million volts AC. So they missed out on an important discovery by only accelerating electrons instead of positive protons.

Fowler got his degree working with Charlie Lauritsen, and then stayed on as a member of the Kellogg Group, it was called, because the Kellogg Corn Flakes people built them a building and provided funds for them. Provided they used the x-ray tube to treat cancer patients a small percentage of the time. There were terminal, inoperable cancer patients that came at four o’clock or something like that. Ambulances were coming and going. Then Willie took over, and the last several years has been running Kellogg Radiation Lab, mostly doing experiments that have to do with the synthesis of elements in the stars, which is one of the things that Willie has been interested in very much.

Sherwin: When you mention cloud chambers—

Anderson: Well, we did some work for them, after the Cockcroft-Walton experiments, when they were making radioactive things. At first I [did], and then later Seth Neddermeyer came as my first graduate student. They would make it in their tube, and would run with a sample from the Kellogg building up to the Aeronautics third floor and take pictures of radioactive carbon, nitrogen. Then Willie built a cloud chamber.

Sherwin: I knew there was a cloud chamber.

Anderson: When he built that, I do not know. Maybe ‘33 or ‘34.

Sherwin: Where is Neddermeyer now?

Anderson: After the war—he was at Los Alamos during most of the war—he went to the University of Washington and is now [professor] emeritus there.

Sherwin: I see. University of Washington in Seattle?

Anderson: Yeah. He said he wanted to be on the Pacific coast, but he later said that he did not consider Seattle as part of the Pacific coast.

Sherwin: Too late. Were you closely associated with Oppenheimer during the ‘30s or later years?

Anderson: You mean socially? The answer is no. I think I was at his house, after he had a house in Pasadena, perhaps a couple of times. But I was a bachelor and I had to support my mother, and I was not in a position to get involved in social affairs much. Supporting a semi-invalid mother on a graduate student stipend—she was a genius to see that this could actually happen. I was not a close friend of Oppie’s at any time.

Sherwin: By the end of the 1930s, did you ever work with him?

Anderson: In the early 1930s. See, the positron came along in 1932, and I talked with Oppie.

Sherwin: You discovered it, didn’t you.

Anderson: Yes. But I was not looking for it. I talked with Oppie when there was enough evidence, so that there was no doubt about the existence of them, and I did not know how to figure out where the darn things came from. I knew about the Dirac theory, and the infinite sea of negative energy states, and the [electron] holes. It is so simple. Any freshman could draw an energy level diagram of the electrons in the atom, and then the negative things and the photoelectric effect. You pick out an electron from an atom. If you have enough gamma ray energy, you can do the same thing.

I never thought of that, even though it was, in hindsight, so simple and obvious, and neither did Oppie. He never came up with the idea of [electron-positron] pair production. I first learned about that in reading [Patrick] Blackett and [Giuseppe] Occhialini’s paper about six months after I published the first note on the—

Sherwin: Positron.

Anderson: On the positron. Of course, Dirac was present at [the University of] Cambridge at that time. I do not think they mention him in their paper, but I have always wondered if he contributed in any way to this idea. But Oppie did not, and this astounds me to this day.

Sherwin: You showed him all the data and everything.

Anderson: Oh everything, yeah. He was welcome to see the good cases and bum cases and everything we had. I just got—a few days ago—an excerpt from an interview that somebody at Berkeley had with Oppie in 1963. Do you know of—?

Sherwin: [Thomas] Kuhn? At the Institute for Advanced Study?

Anderson: Yeah. 

Sherwin: Yeah.

Anderson: There Oppie talks about his thinking in the days of the positron.

Sherwin: Do you think it is inaccurate? I read it.

Anderson: No, I think it is accurate. It says there that he did not think it was a good experiment, and it also says that I was not looking for positive electrons, even though the Dirac theory had been around and had so many successes. It is strange to me that Oppie did not come up with the idea of pair production until six months later, when Blackett and Occhialini published it. Maybe he thought about it, but I never heard anything.

Sherwin: Could you briefly tell the story of the experiment and the discovery of the positron?

Anderson: You want me to tell the story? Well, let me see. I will go back to before I got my Ph.D. degree. This is in the literature; I have written what I am going to say now.

Sherwin: Oh, you have? In that case, can you give me the reference?

Anderson: “Fermilab [Fermi National Accelerator Laboratory] Historical Conference on Early Days of Particle Physics,” or something like that [misspoke: International Symposium on the History of Particle Physics at Fermilab]. Were you there?

Sherwin: No.

Anderson: It was held, I think, in late 1980 [misspoke: May]. I am not sure. 

Sherwin: Yeah.

Anderson: I wrote a paper, and had planned to go but my health would not permit it. But Herbert Anderson read the paper.

 Also, there is an article that was in Physics Today written by these two gals, [Lillian] Hoddeson and [Laurie] Brown who ran the conference—for historians, not physicists—at the Fermilab.

Sherwin: I see.

Anderson: They wrote an article in Physics Today based on the papers that were read at that. So I will not repeat that. I had an experiment in mind that I wanted to do, namely, use the cloud chamber and the magnetic field to look at “thorium C double prime” [also known as thallium-208] radiation. [Chung-Yao] Chao, when I was working with the x-rays, was doing that using electroscopes, and found an excess absorption—which was pair production, it turned out later—and an excess scattering, which was annihilation radiation. It is written up, so I will not say it.

Sherwin: It is very interesting that Oppenheimer did not catch that. Were there any other instances where you were thinking together on a subject and he was either helpful or not particularly helpful?

Anderson: I certainly did not help Oppie in any discussions, and I cannot remember of any where he helped me. I had always had trouble understanding Oppie. It seemed almost mystical, what he was saying, and the resolution was very poor. It was like electron “clouds,’ and not particles. I could never get to the point, really.

Sherwin: Is that true in physics and in other issues too?

Anderson: We had a meeting one day. We both got telegrams from [Arthur] Compton in early ’42. Compton asked me to head the bomb project, and asked Oppie to join the thing as my assistant. I have those telegrams if you want to see them.

Sherwin: Sure.

Anderson: I guess we got our telegrams on the same day, and I remember we sat on the concrete benches in the sophomore lab. I do not know how we happened to be there discussing these telegrams. Oppie was very definite in saying that, so far as he was concerned, it was purely academic, because he knew he could not get the clearance to work on a project like that.

Sherwin: That is interesting.

Anderson: I guess that is about all. I could not do it. I did go to Chicago and saw Compton. I was, I guess, an assistant professor. Anyhow, my salary was about $5,000 a year. The rule was that you could get a 20% increase, I think it was, in salary if you went away to work on a war project. That meant my salary if I went to Chicago—which is where I was supposed to go at that time. This is long before there was Los Alamos, or [it was] even thought of.

For economical reasons, it was completely impossible for me to do this, because I had my mother to support and she could not move to Chicago. So in the very beginning, I knew I could not do it. I did not have to face the other, bigger question about doing it.

I probably would have turned it down even if it were financially possible, because I would have felt I did not have a necessary administrative skills to undertake what I knew would be a big thing. It seemed promising from the cross-sections and things that were known at that time. I still think I would have turned it down, on the basis of not being the right person for that job. I do not know when Oppie took it. Do you know?

Sherwin: Well I have to see those telegrams, but it was some time in ‘41 or ’42. He was involved peripherally with some of this work, some calculations for [Ernest] Lawrence and that sort of thing. Sometime during 1942, late in the summer, [General Leslie] Groves got onto him, I think.

Anderson: When did Groves come into the picture?

Sherwin: Groves comes in in the fall of ’42, I think.

Anderson: This was in early ‘42. I did go back to Chicago. I guess I said that. Saw what Fermi was doing, in building the first Pile, that I think started, actually worked, in December of ‘42.

Sherwin: Yeah. I guess that Groves finally decided that the people who were initially the preferred choices could not do it, and after meeting Oppenheimer Groves was very impressed and simply insisted that he be cleared, in spite of the fact that under the rules and regulations—

Anderson: Yeah.

Sherwin: —he could not be cleared. You did not know anything about Oppenheimer’s political activities, did you?

Anderson: Well, not in a direct way. There were groups of people who would get together—and Oppie was one of them—and have meetings. I was invited to join these groups and never did, except on one occasion. And this is very vague, and it may have nothing to do with Oppenheimer. But there was a meeting. Somebody was to give a speech in a hall in Pasadena one evening, and I went there. I cannot remember who I went with, but I do remember that there were police lined up, all along the sides in the back of this hall. I cannot remember who was the speaker or what the topic was, but it was apparently a communist group of some kind.

Sherwin: Frank Oppenheimer was a graduate student here and he was a member of the Communist Party.

Anderson: He was a so-called “card carrying member.” 

Sherwin: Who did he work with when he was here?

Anderson: Was he ever at Caltech?

Sherwin: Yeah.

Anderson: As a student?

Sherwin: Yep.

Anderson: I did not know that.

Sherwin: Yep, he was here from about ‘36 to ’39, ’40, something like that. Then he went up to Stanford for a year or two, and then was involved during most of the war with Lawrence’s lab [at Berkeley].

Anderson: I got to know Frank Oppenheimer. I do not know what years. He worked with [Edward] Ney in Minnesota.

Sherwin: After the war, yes.

Anderson: On the heavy particle primary rays.

Sherwin: Yes.

Anderson: Yeah. That is the first time I really got acquainted with—

Sherwin: Was it there, out in Minnesota?

Anderson: No, it was at a meeting of the [American] Physical Society somewhere and they reported their work there. I did not know he was at Caltech. That is strange.

Sherwin: I guess by the end of the ‘30s the place was getting a little bit bigger.

Anderson: Well, you still knew the physicists who were around. Of course during the war, I was busy. I worked very hard on the rocket project that Charlie Lauritsen started, and that was a big project. Actually, Caltech made over a million rounds that were used in action, although that was illegal, since the contract was research and development.

Sherwin: What kind? Rounds of what?

Anderson: They were solid propellant artillery rockets, not long-range things. One of the best applications was barrage rockets. You could put a few thousand of them on a PT boat. As they came approaching the beach, all they had before was 50-caliber machine guns, and now they had these 3.5-inch rockets with a cannon shell, ordinary cannon shell, on the head.

Sherwin: The rocket would carry a much further distance.

Anderson: Well, they would just flood the beach with thousands of these barrage rockets. I was in charge of adapting other kinds of rockets, bigger ones, to airplanes. So that is what I did during the war, and worked hard, and actually went over to the beachhead and saw them in action. I have complete proof of one rocket getting two German tanks.

Sherwin: After the war, when Oppenheimer came back here for a bit, did you know him? He was here about six months, I guess.

Anderson: Not close socially, no.

Sherwin: Then he went to the Institute [for Advanced Study] and I suppose that was—

Anderson: That was shortly after the war.

Sherwin: Yes, he only stayed here about six months.

Anderson: Yeah.

Sherwin: He went to the Institute in ‘47.

Anderson: I was not, at that time, in his social group.

Sherwin: I would be grateful if you could show me those telegrams.

Anderson: And he [Compton] also sent me a copy of the one he sent to Oppie. Here is one, May 20. Those are the three.

Sherwin: You made copies.

Anderson: I have never mentioned this to anybody. Now that Oppie is dead and time has passed, I do not mind.  They are negative things. It is nothing I did. I turned them down.

Sherwin: Well, I think it is an interesting part of the history of the whole thing, and you had very good reason for doing it. And the story you told me in connection with Oppenheimer thinking it was academic is an important piece of history.

Anderson: He was very clear on that point. Because Oppie, as far as I know, did a tremendously good job on the whole thing.

Sherwin: I would be interested too in any possible views that you had in terms of Oppenheimer’s scientific work.

Anderson: Well, I have always had, even in the very early days, tremendous respect and admiration for him. I thought, even when I took his class so unsuccessfully, he was an extremely erudite person. Probably knew more physics than anyone else in the world, and then his success in his “school,” you might say, at Berkeley of training a whole slew of top-notch theoretical physicists. That was a great contribution there.

Sherwin: Yes.

Anderson: As well as his direct personal research. I think he had a very major influence on the country and the world, therefore, in training all these people and making a big contribution to theoretical physics in the country. Or world; it is an international thing, obviously.

Sherwin: Yeah. It is interesting that he missed the positron—

Anderson: The interpretation, yes.

Sherwin: Do you happen to recall the circumstances, the day when you showed him this? Was it some afternoon, he came into your office, or did you go over to his office?

Anderson: It was on several occasions, not any one. There was this one picture that clinched it, but before that, there was evidence of something. When the apparatus was first turned on, I found—Neddermeyer was not with me in those days—about an equal number of positive and negative particles.

99% of the cases you could not learn anything about the mass. That is the first thing you think: what is the mass? But there were many cases in which the curvature was high enough—that is, the velocity and the energy and the momentum was low enough—so that you would have expected a darker, more heavily ionizing track. But you could not be sure; light varied in different positions of the chamber. But that evidence kept building up. I would talk to Millikan, who started me on this job and was very much interested in it, and would have arguments. I would say, “They have to be electrons going up that have been scattered.”

He would say, “You are crazy, everybody knows cosmic rays come down, they don’t go up.” So there was a feeling that these were not protons, which was pretty strong. And then I decided to put that lead plate in there, and hope to find one of low enough energy. And one did come along that was very clear-cut, and that was an upward-going one, incidentally. That clinched it. But I do not remember too much about my conversations with Oppie, except the ones I mentioned before, the fact that he did not come up with the idea of pair production.

Sherwin: Yeah.

Anderson: Which I think he should have, and I think I should have, or any freshman should have. But it is one of those things.

Sherwin: What were his best interpretations?

Anderson: He never had an interpretation of it. He did not believe in the Dirac theory, and he says that, essentially—

Sherwin: Yes.

Anderson: —in that interview. And that of course would keep him from—

Sherwin: Thinking about it.

Anderson: —thinking about it in the proper way.

Sherwin: Yeah.

Anderson: He never had any interpretation. I tried to figure out some way they came from the nucleus, because they had a positive charge, even though I knew electrons could not exist in the nucleus because of the indeterminacy principle.

Sherwin: What did Millikan think of Oppenheimer? Did you ever talk to him about—

Anderson: No I never did. So far as I know, the fact that Oppie was present at Caltech, I am sure he had Millikan’s full support. I do not know at all whether Oppie was on salary. He was a wealthy person. Knowing Millikan, if he could get Oppie without paying him a salary, he would do it. As far as I know, Millikan thought Oppie was an unusual person, apparently.

I do know that [James R.] Page, who was Chairman of the Board of Trustees, said that he was going to try very hard to get Oppie as Division Chairman of Physics, Math, and Electrical Engineering. But he also said he did not expect that he would be successful.

Sherwin: I see. When was this?                                                  

Anderson: That was right after the war.

Sherwin: After the war, I see.

Anderson: Right after the war. Millikan had that job as well. He was never, by name, president of Caltech. He was “Chairman of the Executive Council.”

Sherwin: I see. So Lee DuBridge was the first president.

Anderson: First president.

Sherwin: I see.

Anderson: But Millikan had more power and exercised more power than—

Sherwin: Anybody.

Anderson: —a president normally would. I mean, after all, he made the place.

Sherwin: What was it like here in the early days? Where were you born?

Anderson: New York City, and the family moved out to Los Angeles when I was seven years old. I went to high school later, L.A. Poly High [now John H. Francis Polytechnic High School], and there were four of us who wanted to go to Caltech.

Sherwin: At that time was it Caltech yet or was it—

Anderson: It was Caltech. This was ‘23, and Millikan, I think, came full time in ’21. He was part time from ‘16 to ‘21. The four of us asked for advice from our teachers, and they all strongly advised us against going there. They said, “It is too hard to get in, you probably won’t get in. If you do, you will work so hard, you will wear yourself out and won’t be worth anything.” Except our physics teacher: he said he thought it might be all right. Anyhow, the four of us went over, and we all got in, we all stayed for graduate work, and got our Ph.D.’s on the same day.

Sherwin: Who are the other three?

Anderson: A fellow by the name of Lewis Gazin. When I was on my travel prize, he was a physicist. We were very close friends through high school. He turned geologist and has been at the National Museum all his life, paleontologist.

Sherwin: I see.

Anderson: The other one was a chemist, Bernard Moore, who last I know went to Venezuela on some oil business. The fourth one was Thomas Gautier, who was an electrical engineer. Those were the four of us.

Sherwin: What was Caltech like in those days?

Anderson: Very much smaller. There were very few buildings. I do not know if you know the buildings. Throop Hall disappeared; that was the first building. I do not know the early history, except Throop Hall was built about 1910-11.

One thing that was very nice was that [Arthur] Noyes was head of the Chemistry Division. He was a bachelor, and he used to ask students to go on weekend camping trips with him, and I went. He also had a house in Balboa [Peninsula, in Newport Beach, CA]. That property later became the Caltech Marine Station. Quite a piece of property, that in the 1930s, I guess, anybody could have bought for a couple hundred an acre. And now it is two hundred dollars a square foot or something like that.

It was great to spend these weekends with Noyes. We would go up to Painted Canyon, which is across the [Coachella] Valley from Palm Springs, on the east edge of the valley, and actually camp out for two or three days. To get acquainted with a guy like Noyes is very worthwhile.

There were many similarities: the general way the undergraduate students were handled, the way the classes were divided up and arranged, twenty to a section. About the same, except now there are somewhat, but not very many more, undergraduate students.

Sherwin: It is about 800, or something like that.

Anderson: It was 623.

Sherwin: Extraordinarily small. Just amazing.

Anderson: Tuition was $200 a year. What is it now? It was $66.66 a term. There are three terms. I paid tuition the first term, but I did not have to pay any [more]. I got scholarships.

Yeah. I remember [Richard] Feynman telling about when he found that going to class was not compulsory at MIT. He said then he really started to get an education.

Sherwin: Right. There are people like that—

Anderson: But he is such a remarkable guy. He is quite different from Oppie. When you ask Feynman a question, you get a very sharp answer. It is probably my fault but—

Sherwin: What you said—

Anderson: —with Oppie a mysticism seemed to come in.

Sherwin: Yes.

Anderson: I did not learn anything. Have other people said that?

Sherwin: Yes: very abstract, always gave you the most complex answer possible. [Enrico] Fermi did not like him at all.

Anderson: No. Fermi was just the opposite.

Sherwin: He was like Feynman.

Anderson: Yeah.

Sherwin: Right to the point.

Anderson: I would guess he is probably the best teacher in the world, because everything he said was simple and you could understand it. Well, it is like his books and writings.

Sherwin: There is a story that Fermi tells, that is somewhat like the story you told about the first day in class. He says he went to an Oppenheimer seminar. And he said he did not understand a word until the last sentence, which was something to the effect that Oppenheimer explained, “—and this was Fermi’s theory of something.” [Laughter]

Anderson: That is a good one. Well, Fermi also has a lot of good stories.

One thing I wanted to tell you: Millikan asked many prominent European physicists to come to Caltech in the early days in the late ‘20s and early ‘30s, when you could not come by air overnight.

Sherwin: Yeah.

Anderson: He got many people to come over. I remember [Paul] Ehrenfest, who would give lectures on relativity, ether wind. And you could just feel it blowing across the seats. I mean he was such a colorful—

Well, he was sitting in the front row, and Oppie was giving a seminar. This was in the early days, again, before Oppie became so eloquent. I do not know if it happened all of a sudden or how. Ehrenfest had a loud voice and he said in a loud voice, “Dr. Oppenheimer, is this a secret?” I cannot imitate Ehrenfest’s accent.

Sherwin: Oppenheimer was speaking too low.

Anderson: Yeah. He faced the blackboard, and he was writing something you could not see, and Ehrenfest could not hear him in the front row.

Sherwin: Yes. Did he continue to harass him at all?

Anderson: Well, this is so long ago, and I just happened to remember that “is this a secret” remark. I suppose Oppie talked louder. I remember Harry Bateman. I took a class from him once, and he wrote microscopically on the blackboard, so even in the front row you could not [see]. Then someone asked him, “Please write larger.” So then he wrote a great big letter, about a foot high, and in four feet he was down to the little microscopic writing again. So maybe Oppie spoke loud for two or three words, I do not remember.