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Louis Hempelmann’s Interview – Part 3

Louis Hempelmann was J. Robert Oppenheimer’s physician and close friend. In this interview, he discusses the hierarchy at Los Alamos, what it was like to work with Kitty Oppenheimer, and Kitty and Robert’s relationship. He recalls his interactions with Oppie, Enrico and Laura Fermi, and Edward Teller, and the parties that Oppenheimer and others used to throw at Los Alamos. Hempelmann remembers driving to Trinity Site with George Kistiakowsky and the high explosives—on Friday the 13th.

Date of Interview:
August 10, 1983
Location of the Interview:


Martin Sherwin: What was the set-up at Los Alamos, in terms of your relationship to the director [J. Robert Oppenheimer] and how you operated?

Louis Hempelmann:  I was working directly under him. I started out with my wife as a half-time secretary, and the technician I brought with me from St. Louis, and Kitty worked for me.

Sherwin: What did Kitty do for you?

Hempelmann: Did blood counts.

Sherwin: Was she a good technician?

Hempelmann: Oh, yeah. She was awful bossy. She went to Robert one time, not in my presence. She said she didn’t think the blood counts meant anything. She could not see why we did it. Robert told me that and I said, “Well, if you want to stop doing blood counts, then you are going to have to get yourself some other boy, because that is the policy that the Manhattan Project had.” I said, “She is probably right. But we have got to keep on doing them, and if you want to stop, you had better get yourself somebody else.”

She was sort of bossy to the technicians. Then she stopped after about a year or so.

Sherwin: Voluntarily?

Hempelmann: Yeah.

Sherwin: Did she work for anyone at that point on?

Hempelmann: No. This may have been the time that she was pregnant with Toni.

At the same time, Laura Fermi was working for me too, so we had quite a famous group, of wives there, anyway. Oh God, she is the nicest person in the world.

Sherwin: Yeah, I have not met her. I have read some of her books. I should talk to her.

Hempelmann: She was so gentle. I don’t know what you can get from her, though, about the Oppenheimers. I do not think they were particularly close.

Sherwin: No, there was a tension between Fermi and Oppenheimer. I would like to get her to try and describe it, but if you think she might or might not—

Hempelmann: Yeah.

Sherwin: They were, as physicists, the exact opposite in terms of how they dealt with physics and their personalities.

Hempelmann: I do not know enough physics to judge, but I gather that Oppie was a very brilliant guy and a brilliant critic, but he was not the most imaginative person in the world.

That is the sense that I got. Whereas Fermi was imaginative. He could work in the laboratory, he was a brilliant theoretician, and a marvelous physicist. But Oppie was the teacher and the critic, as I understand it.

Sherwin: Physicists described their style as: Fermi was very straightforward, to the point, the simplest possible terms. Anyone who was capable of understanding the kind of physics he was talking about would understand what Fermi was driving at immediately. Whereas Oppenheimer—there is a story that Fermi was the opposite.  

Fermi tells the story—I think this was passed on to me by someone. Fermi went to a seminar at the Institute [for Advanced Study]. He came out and told a story to his colleagues and he said, “I must be getting terribly old. I was at this seminar, and I did not understand one word for a whole hour. It was all Oppenheimer’s students’ explainers. He says, “The only thing I understood was the last sentence when Oppenheimer said, ‘And this is Fermi’s theory of whatever.’

That was Fermi’s rather sort of cutting way, I think, of telling the story to a friend of his about how everything was glamorized and complicated. Fermi did not like that way of dealing with things.

Hempelmann: Most of the important people had these houses that had belonged to the schoolmasters.

Sherwin: Bathtub Row.

Hempelmann: Bathtub Row. But not Fermi, because he did not come until—

Sherwin: Later.

Hempelmann: A little bit later, and so they used to have an apartment fairly near us. When Laura was working for me, I used to walk home. We used to walk home together, we would get to my house first, and then she would go on to her house.

She did tell me one time that for years she had been using a double-boiler, and she would not close the thing until after the water started to boil. Enrico saw her doing that one time. He said, “Oh no, you close it first.”

I said, “Well it must be wonderful to be married to a knowledgeable physicist like that who can help you do so many things.”

She said, “Well, when he was applying for oil in Chicago, he put the decimal point in the wrong place, and they nearly froze to death.” So he was not always perfect either.

Sherwin: That is right, in practical terms, I guess.

During this period when Kitty was working for you, I would like to try to connect up her personality with some of the ways it manifested itself in the job. Everybody agrees that she was a very bright person, and that she was a strong personality and competitive. Of course, these were the early years of their marriage too, and all of this coming at the same time—her husband was essentially taken away from her, I suppose, by the job and the tension. She was stuck on her own during the Los Alamos period. Now, is that right?

Hempelmann: No, I do not think so. They were terribly close, and he would come home in the evenings whenever he could. Of course, sometimes he had to go back, or something like that. But I do not think she was alone.

Sherwin: How about his having all the important things to do and being the center of attention, and her being very much on the periphery?

Hempelmann: I think she was proud of him, and she got a lot of the glory. But I think she was [inaudible]  in the center of things.

Sherwin: Do you think that this situation of being married to suddenly a great man—is something that I have to grapple with and is a clue to pursuing the situation? For example, she married him in 1940, after a very intense and brief romance. He was a physicist at Berkeley, brilliant, charming, and everything else, but there you are.

Hempelmann: I used to see him out there, even before I knew him. They had a Cadillac. They had a name for it, but he would park right under my laboratory window at the Crocker Laboratory. He would drive up with this cute young girl. She was very attractive in her earlier days and towards the end, she lost her looks, really. She was skinny as a rail, just like he was; she was a tiny little thing. They would drive up and they would give to each other a fond kiss, and then they would go their separate ways. Robert always had that porkpie hat on.

Sherwin: This was even before Los Alamos?

Hempelmann: Yeah. Then I saw him in a meeting one time without his hat. It was the first time I had ever seen him without a hat. I did not recognize him, because he used to wear his hair very long and very curly, just like Frank. I think Frank still does. I have not seen him.
By the time Robert came to Los Alamos, I almost did not recognize him again, because by this time, he had his hair very closely clipped.

He [Oppenheimer] was very thoughtful and considerate of his friends, and I think I can understand how that [Haakon] Chevalier thing came about, because he did not want—he wanted to be loyal to his friend, and he did not want to mention anything about it. He did voluntarily, but I think he was just protecting a friend.

There was a test of the implosion method, which I suppose was in the winter, end of the fall of 1944, and the winter and spring of ’45. What it was, they would have some metal shell, something like the implosion bomb that was used. They would have these—what are they called? The type of explosives, some sort of [inaudible] charges—

 Sherwin: Lenses, right.

Hempelmann: Lenses, yeah. They would put a very highly radioactive material in the center of this thing, and then they would implode it. They would have counters on the outside that would see how evenly this thing collapsed, you see.

Sherwin: This was [Charles] Critchfield’s group? [Rubby] Sherr and Critchfield?

Hempelmann: No, it was—

Sherwin: [George] Kistiakowsky?

Hempelmann: Luis Alvarez.

Sherwin: Alvarez.

Hempelmann: We used to get this shipment of radioactive lanthanum from Oak Ridge, several thousand curies, which is a hell of a lot of radioactivity. Then this was decayed radiolanthanum, which had a very penetrating gamma ray. They would milk off the lanthanum, and then blow this thing up in the area. If we did that now, we would get into all sorts of trouble.

Anyway, the first shipment was coming out of Oak Ridge by truck, and it was coming by the canyon.

Sherwin: A lead box?

Hempelmann: Yeah. I was supposed to meet it. I called up Robert and asked him if he could give me a ride there. He said no, he could not because had this meeting with all the big shots from Washington. Why did not I go down there by myself, which was in a near-by canyon?

I went down to the stables and I got my horse. I was just starting off, and there was no telephone down there. [Inaudible] Here was Robert. He said he got word that this shipment was not going to come in until after dark and not to go down there, but to take an easy ride. He had gotten out of that meeting and dashed down there just to keep me from maybe getting—

Sherwin: Stranded.

Hempelmann: —in a difficult position. He was very thoughtful about things like that, especially to his friends.

Sherwin: That was also very characteristic, I gather, of his whole directorship, and one of the reasons he was so well liked by the whole spectrum of people.

Hempelmann: Yeah.

Sherwin: Was he extraordinarily efficient?

Hempelmann: Oh, I think so, yeah. He was a clean-desk man.

Sherwin: Oh, really? Well, I guess that figures along with everything else. I had not known before you mentioned to me that he was essentially a sight reader.

Hempelmann: Peter had told me he had developed it. I did not know that.

Sherwin: Yeah. He was certainly a speed writer. He could sit down and write a memorandum about a meeting that read like poetry, and do it first draft.

Hempelmann: Yeah.

Sherwin: It was really terrific. Did he ever talk to you about his difficulties with [Edward] Teller?

Hempelmann: Well, no. I remember though during one of these high-energy physics meetings—

Sherwin: At Los Alamos?

Hempelmann: No, at here. They were both here. They had not met, and they met in the cafeteria lines. I did not see this, but he told me about it. They were getting closer, and everyone was just on edge waiting to see what would happen. When they got to a point where they could not ignore each other, he just said to him, “Hello, Edward, how are you?” That just relieved the tension. I do not know what they thought might happen.

Sherwin: This was shortly after—do you recall?

Hempelmann: I do not know if it was the first time that they met after the trials or not. But I would not be surprised.

Sherwin: It was a high-energy conference here?

Hempelmann: Yeah, a high-energy conference.

Sherwin: Not at the hospital, but at the University of Rochester in the physics department?

Hempelmann: Yeah. Many of these things I think I can give you clues, but I think other people could tell the stories better. I was not there.

Sherwin: Yeah. Do you know who else was there at the conference? Can you date it, you know, ’55, ’57,’59?

Hempelmann: No.

Sherwin: Okay. I just want to drag out whatever clue I can.

Hempelmann: Bob Marshak was the chairman of the physics department. He organized the meetings. 

As I say, I should not be talking about physics or anything like that.

Sherwin: It is not the physics so much as Teller and that whole relationship. In terms of Teller’s behavior at Los Alamos, do you recall any specific instances or other meetings?

Hempelmann: I did not have much contact with him.

Sherwin: I know what I wanted to ask you. I was told that at Los Alamos, on the day of [President Franklin] Roosevelt’s death, April 12, 1945, it was Robert who announced it in whatever the big assembly hall is.

Hempelmann: Oh, yeah.

Sherwin: He gave a very moving and short speech. Do you remember anything about that?

Hempelmann: No. At that particular time, I was out at Trinity. We were holding some preliminary tests with 200 tons of TNT, or something like that.

Sherwin: I see.

Hempelmann: So on the day of Roosevelt’s death, I remember being down there.

Sherwin: Who were you down there with? Kistiakowsky, I suppose?

Hempelmann: No.

Sherwin: Critchfield?

Hempelmann: You know Kistiakowsky?

Sherwin: Not very well, but I know him.

Hempelmann: He could give you some good stories.

Sherwin: Oh, yes.

Hempelmann: I was up at Los Alamos the week of the ninth or tenth of July. We were having a lot of trouble with the plutonium workers, because we were getting so much plutonium [inaudible] so heavily exposed.

Sherwin: You were having trouble with the?

Hempelmann: With their exposures.

Sherwin: The people who were handling the plutonium?

Hempelmann: Yeah. I was staying up there. I got this call from Robert telling me to get the hell down to Trinity, that the day was approaching.

I had my choice—by that time, so many of the cars, Army cars were gone, that I had the choice of riding down in an open jeep with Norris Bradbury, or going down with Kistiakowsky with the high explosives. I thought the latter would be more comfortable, so I went with George. He is a great showman, you know. We left at 12:01 AM on the morning of Friday the 13th.

Sherwin: He wanted to go on the 13th?

Hempelmann: Yes.

Sherwin: That is what, about 300 miles?

Hempelmann: About 250, I think.

Sherwin: 250 miles. How did they pick the Trinity site, do you recall?

Hempelmann: They had looked at a lot of sites out—I think you can tell in that City of Fire [by James Kunetka]. I think Jim goes into that.

Sherwin: I have read it.

Hempelmann: I think [Kenneth] Bainbridge was in charge of it. He surveyed a lot of [inaudible], one out in California.

Sherwin: Back to Kitty for a moment and her situation at Los Alamos.

Can you recall any parties at the Oppenheimer house, for example? What kind of hostess Kitty was?

Hempelmann: Oh, she was wonderful. I can tell you, the first big party they had was on his fortieth birthday, which I think was April 1943. You know when he was born?

Sherwin: Yes, 1904 or ’05.

Hempelmann: No, the day? It was April.

Sherwin: No, I do not know.

Hempelmann: April or May. People were arriving there, and many of the wives were not there. [Isidor I.] Rabi was there, and Cyril Smith, who was the head of metallurgy and I think essentially was responsible for the plutonium bomb. Oh, [Hans] Bethe, and my friend Jim Nolan and his wife. It was the gayest party, and the alcohol history hits you harder.

Sherwin: At 8,000 feet.

Hempelmann: Everybody, even the most sober people like Rabi, were feeling no pain at all. Everyone was dancing, and we all had a marvelous time. I think we all got tighter than we thought. Had we drunk the same amount at a lower level, it would not have affected us at all, but I think that is what gave us such a good time. Oppie danced in the same way, in this old worldly manner, holding his arms way out; classic.

Sherwin: Classic foxtrot or waltz kind of thing?

Hempelmann: Yeah.

Sherwin: Now, you said it was his fortith birthday. If I recall correctly, he was born 1904, but maybe it was 1903, because this must have been in 1943.=?

Hempelmann: 1943. Maybe it was his thirty-ninth.

Sherwin: Okay. Would it have been the same week that meeting that took place?

Hempelmann: I think it was probably shortly thereafter, because Rabi was there for that meeting.

Sherwin: That is right. That is what I was asking. Rabi never stayed for—

Hempelmann: He would stay for a month.

Sherwin: Oh, he came for periods of a month or so?

Hempelmann: Yeah.

Sherwin: Okay. Were there other occasions of particular note in this light vein?

Hempelmann: Oh, sure. There were so many of them that I do not remember. We would work six days a week, and then on Saturday night there was usually a big blast, a dormitory dance or something like that, or somebody would give a good party.

We and the Nolans gave a party one time at the local PX. The theme of it was, “Come as your suppressed desire.” Oppie came with an ordinary suit on with a napkin over his arm. He wanted to be a waiter, you see. All the doctors came in their pajamas as gold bricks. Lindsey Helmholtz’s wife, whose name I think was Alice, she came dressed in her city clothes with a hat on and gloves and a suitcase. That was her expressed desire; she wanted to get the hell out of there as fast as she could. That was a very gay party.

Sherwin: Who did you dress up as?

Hempelmann: Oh, I am sort of embarrassed. I came dressed up in my own pajamas and robe, with a big sign, “I am Rita Hayworth.”

Sherwin: And your wife?

Hempelmann: I have forgotten what she did.

Sherwin: Do you remember Rabi? Was he there?

Hempelmann: No.

Sherwin: Bethe, how about Bethe?

Hempelmann: I do not remember him.

Sherwin: Okay. Teller?

Hempelmann: One of the English contingent, who shall be nameless, had never been to an American cocktail party. This was not a cocktail party. We served cocktails, and then we had dinner. I do not know how many people were there, maybe seventy-five.

He was not used to the American cocktails, and he passed out and was taken home on a door, you see. He tells the story on himself. He says he had been warned about the American cocktails, and he was known to not have a very good head for liquor. He was embarrassed that it happened, but now he talks about it very freely.

Sherwin: Well, who is it, if he talks about it freely?

Hempelmann: Oh, I would rather not say.

Sherwin: Okay.

Hempelmann: Ask the people there who remembers the English.

Sherwin: The English contingent; now I spoke to [Rudolf] Peierls. He was the head of the English group, wasn’t he?

Hempelmann: Yeah. We did not know him terribly well. I mean, we did not see him socially.

Sherwin: About how many people would show up to a party like this? Like you said, Teller was not there, and that is essentially—were you not friendly with Teller at the time?

Hempelmann: I do not remember. I do not think I had much to do with him.

Oh, Rabi, at that first party I was talking about, at that birthday party, he got out his comb, and then got some toilet paper, and then he was playing the comb for everybody that gathered around. He insisted that if you played the comb, you had to use toilet paper because that was the only one that gave a good tone.

Sherwin: How did he use the toilet paper? He wrapped it around the comb, or something?

Hempelmann: Yeah. Have you not ever seen that done?

Sherwin: No. I am a spoon man myself.

Hempelmann: Oh, you are?

Sherwin: Strictly spoon.

Hempelmann: Do you remember that book, Day of Trinity?

Sherwin: Oh, yes, the Time correspondent [Lansing Lamont].

Hempelmann: The Time reporter, yeah.

Sherwin: His name has slipped my mind.

Hempelmann: He came here and talked to me. I did not know what to do, so I called Robert. At that time, he was very down on time. I said to him, “What will I say?”

He said, “Well, if he is from Time, do not say anything.”

So I told him stories, but I told him to keep my name out. The things were written, but he attributed it to a staff member or something like that.

Sherwin: Yeah.

Hempelmann: Incidentally, although Oppie was opposed to having the thing written by a man from Time and although he said there were many inaccuracies, he said he thought that the fellow did capture the flavor of the moment.

Sherwin: Of that July 16, 1945. Yes, it was an exciting book. I have not only read the book, but he left all his notes and his papers, or at least the transcripts, at the Truman Library.

Hempelmann: Oh, really?

Sherwin: I have gone through them. Yeah, he had a lot of good material and a good sense of—

Hempelmann: He was a relative of one of the early trustees of the University here.

Sherwin: Oh, of Rochester?

Hempelmann: Yeah. A fellow named Minor, who gave them money for our medical library.

Sherwin: I think I have heard of—how do I know Minor? Maybe he was involved in other things. [Inaudible] These stories of the parties are quite interesting.

Hempelmann: Part of the thing is that, as I say, I do not talk about this too my medical colleagues. What it sounds like, and I think they feel, is that I’m making myself seem important. Out there at the time, this was all just in a day’s work.

Sherwin: Yes, of course.

Hempelmann: I probably knew more physicists when I left there then medical people.

Sherwin: Did you keep in touch with many of physicists besides Oppenheimer?

Hempelmann: I did for a period of about ten years with these meetings. Most of them would come out to these high-energy physics meetings. I have seen John Lawrence a couple of times. Cyril Smith, who was the chief metallurgist. He went to MIT. He is retired now, but he came to Rochester. His wife is a historian.

Sherwin: Alice Kimball Smith.

Hempelmann: Yeah, and Cyril is very scholarly and interested in art. He came here to give a talk to the physics department on something like art and the solid state, or something like that. The fellow who arranged for him to come is our next-door neighbor. We have been friends since—well, he was the fellow who operated the St. Louis cyclotron. He is a physicist named is Larry Fulbright. I have known him since 1940 or ’41, I guess.

He had Cyril to dinner, and my wife and me. We had a wonderful time. Then I went to his lecture thinking maybe I could get something out of it. The only thing—well, like Fermi—I only understood one sentence. He started out by saying, “To be a subspecialist, you have to have a specialty.” After that, I was completely lost. 

But he is such a nice man, and we had a marvelous evening. There is some sort of a camaraderie that we had, the people who were out there.

Sherwin: Yeah. Well, when you work six days a week together on this project, and party on Saturday night—

Hempelmann: Oh, then I was on the Board of Trustees of Universities the Associated Universities Incorporated. It runs Brookhaven and the radio-astronomy lab. We used to meet three or four times a year. I would see Rabi there. The physicists, many of them would rotate through, so I saw them there, and of course some at Brookhaven [inaudible] came out there.

Sherwin: Were you at Rochester when this story broke in the Rochester—what is the newspaper in Rochester? The Gazette?

Hempelmann: D&C Times.

Sherwin: Democrat—

Hempelmann: Times-Union and Democrat and Chronicle.

Sherwin: About Oppenheimer’s testimony with respect to Bernard Peters?

Hempelmann: I was here, but I do not remember that. Hannah was the wife’s name.

Sherwin: Hannah Peters, yes.

Hempelmann: She was in the laboratory right next to that place we kept your—

Sherwin: Tape recorder.

Hempelmann: Tape recorder, yes. What that was all about, I do not recall.

Sherwin: Okay.

Hempelmann: His being a communist and Oppie said something, I forgot what it was.

Sherwin: Yeah, it was a very bad thing. But you do not remember anything about it?

Hempelmann: Also, I never did meet him, Peters.

Sherwin: He was a student of Oppenheimer’s during the 1930s.

Hempelmann: Was he?

Sherwin: Yeah. That’s how he knew that Hannah was a doctor. They were very close, actually, for a while.

Hempelmann: I steered clear; I think she was in the next laboratory or something, though I did not want to get involved.

Sherwin: Did they stay around here? They left shortly after that.

Hempelmann: Oh, I came in 1950, and they must have been around for two or three years.

Sherwin: Okay, you don’t remember because I think it was before you came. I did not realize you came that late. Yeah, I think this happened in ’49.

Hempelmann: Maybe that is it then. I steered clear of it because of knowing the wife. 

Copyright 2005 Martin J. Sherwin. This transcript may not be quoted, reproduced, or redistributed in whole or in part by any means except with the written permission of Martin J. Sherwin. Rights granted to Atomic Heritage Foundation.