1*Adapted from a talk given in the First Annual Santa Barbara Lectures on Science and Society at the University of California at Santa Barbara in 1975. "Los Alamos from Below" was one of nine lectures in a series published as Reminiscences of Los Alamos, 1943­1945, edited by L. Badash et al., pp. 105­132. Copyright © 1980 by D. Reidel Publishing Company, Dordrecht, Holland.

2When I say "Los Alamos from below," I mean that. Although in my field at the present time I'm a slightly famous man, at that time I was not anybody famous at all. I didn't even have a degree when I started to work with the Manhattan Project. Many of the other people who tell you about Los Alamos ­­ people in higher echelons ­­ worried about some big decisions. I worried about no big decisions. I was always flittering about underneath.

3I was working in my room at Princeton one day when Bob Wilson came in and said that he had been funded to do a job that was a secret, and he wasn't supposed to tell anybody, but he was going to tell me because he knew that as soon as I knew what he was going to do, I'd see that I had to go along with it. So he told me about the problem of separating different isotopes of uranium to ultimately make a bomb. He had a process for separating the isotopes of uranium (different from the one which was ultimately used) that he wanted to try to develop. He told me about it, and he said, "There's a meeting. . ." I said I didn't want to do it.

4He said, "All right, there's a meeting at three o'clock. I'll see you there." I said, "It's all right that you told me the secret because I'm not going to tell anybody, but I'm not going to do it."

5So I went back to work on my thesis ­­ for about three minutes. Then I began to pace the floor and think about this thing. The Germans had Hitler and the possibility of developing an atomic bomb was obvious, and the possibility that they would develop it before we did was very much of a fright. So I decided to go to the meeting at three o'clock.

6By four o'clock I already had a desk in a room and was trying to calculate whether this particular method was limited by the total amount of current that you get in an ion beam, and so on. I won't go into the details. But I had a desk, and I had paper, and I was working as hard as I could and as fast as I could, so the fellas who were building the apparatus could do the experiment right there.

7It was like those moving pictures where you see a piece of equipment go bruuuuup, bruuuuup, bruuuuup. Every time I'd look up, the thing was getting bigger.

8What was happening, of course, was that all the boys had decided to work on this and to stop their research in science. All science stopped during the war except the little bit that was done at Los Alamos. And that was not much science; it was mostly engineering. .

9All the equipment from different research projects was being put together to make the new apparatus to do the experiment ­­ to try to separate the isotopes of uranium. I stopped my own work for the same reason, though I did take a six­week vacation after a while and finished writing my thesis. And I did get my degree just before I got to Los Alamos ­­ so I wasn't quite as far down the scale as I led you to believe.

10One of the first interesting experiences I had in this project at Princeton was meeting great men. I had never met very many great men before. But there was an evaluation committee that had to try to help us along, and help us ultimately decide which way we were going to separate the uranium. This committee had men like Compton and Tolman and Smyth and Urey and Rabi and Oppenheimer on it. I would sit in because I understood the theory of how our process of separating isotopes worked, and so they'd ask me questions and talk about it. In these discussions one man would make a point.

11Then Compton, for example, would explain a different point of view. He would say it should be this way, and he was perfectly right. Another guy would say, well, maybe, but there's this other possibility we have to consider against it.

12So everybody is disagreeing, all around the table. I am surprised and disturbed that Compton doesn't repeat and emphasize his point. Finally, at the end, Tolman, who's the chairman, would say, "Well, having heard all these arguments, I guess it's true that Compton's argument is the best of all, and now we have to go ahead." It was such a shock to me to see that a committee of men could present a whole lot of ideas, each one thinking of a new facet, while remembering what the other fella said, so that, at the end, the decision is made as to which idea was the best ­­ summing it all up ­­ without having to say it three times. These were very great men indeed.

13It was ultimately decided that this project was not to be the one they were going to use to separate uranium. We were told then that we were going to stop, because in Los Alamos, New Mexico, they would be starting the project that would actually make the bomb. We would all go out there to make it. There would be experiments that we would have to do, and theoretical work to do. I was in the theoretical work. All the rest of the fellas were in experimental work.

14The question was ­­ What to do now? Los Alamos wasn't ready yet. Bob Wilson tried to make use of this time by, among other things, sending me to Chicago to find out all that we could find out about the bomb and the problems. Then, in our laboratories, we could start to build equipment, counters of various kinds, and so on, that would be useful when we got to Los Alamos. So no time was wasted.

15I was sent to Chicago with the instructions to go to each group, tell them I was going to work with them, and have them tell me about a problem in enough detail that I could actually sit down and start to work on it. As soon as I got that far, I was to go to another guy and ask for another problem. That way I would understand the details of everything.

16It was a very good idea, but my conscience bothered me a little bit because they would all work so hard to explain things to me, and I'd go away without helping them.

17But I was very lucky. When one of the guys was explaining a problem, I said, "Why don't you do it by differentiating under the integral sign?" In half an hour he had it solved, and they'd been working on it for three months. So, I did something, using my "different box of tools." Then I came back from Chicago, and I described the situation ­­ how much energy was released, what the bomb was going to be like, and so forth.

18I remember a friend of mine who worked with me, Paul Olum, a mathematician, came up to me afterwards and said, "When they make a moving picture about this, they'll have the guy coming back from Chicago to make his report to the Princeton men about the bomb. He'll be wearing a suit and carrying a briefcase and so on ­­ and here you're in dirty shirtsleeves and just telling us all about it, in spite of its being such a serious and dramatic thing."

19There still seemed to be a delay, and Wilson went to Los Alamos to find out what was holding things up. When he got there, he found that the construction company was working very hard and had finished the theater, and a few other buildings that they understood, but they hadn't gotten instructions clear on how to build a laboratory ­­ how many pipes for gas, how much for water. So Wilson simply stood around and decided, then and there, how much water, how much gas, and so on, and told them to start building the laboratories.

20When he came back to us, we were all ready to go and we were getting impatient.

21So they all got together and decided we'd go out there anyway, even though it wasn't ready.

22We were recruited, by the way, by Oppenheimer and other people, and he was very patient. He paid attention to everybody's problems. He worried about my wife, who had TB, and whether there would be a hospital out there, and everything. It was the first time I met him in such a personal way; he was a wonderful man.

23We were told to be very careful ­­ not to buy our train ticket in Princeton, for example, because Princeton was a very small station, and if everybody bought train tickets to Albuquerque, New Mexico, in Princeton, there would be some suspicions that something was up. And so everybody bought their tickets somewhere else, except me, because I figured if everybody bought their tickets somewhere else. . .

24So when I went to the train station and said, "I want to go to Albuquerque, New Mexico," the man says, "Oh, so all this stuff is for you!" We had been shipping out crates full of counters for weeks and expecting that they didn't notice the address was Albuquerque. So at least I explained why it was that we were shipping all those crates; I was going out to Albuquerque.

25Well, when we arrived, the houses and dormitories and things like that were not ready. In fact, even the laboratories weren't quite ready. We were pushing them by coming down ahead of time. So they just went crazy and rented ranch houses all around the neighborhood. We stayed at first in a ranch house and would drive in in the morning.

26The first morning I drove in was tremendously impressive. The beauty of the scenery, for a person from the East who didn't travel much, was sensational. There are the great cliffs that you've probably seen in pictures. You'd come up from below and be very surprised to see this high mesa. The most impressive thing to me was that, as I was going up, I said that maybe there had been Indians living here, and the guy who was driving stopped the car and walked around the corner and pointed out some Indian caves that you could inspect. It was very exciting.

27When I got to the site the first time, I saw there was a technical area that was supposed to have a fence around it ultimately, but it was still open. Then there was supposed to be a town, and then a big fence further out, around the town. But they were still building, and my friend Paul Olum, who was my assistant, was standing at the gate with a clipboard, checking the trucks coming in and out and telling them which way to go to deliver the materials in different places.

28When I went into the laboratory, I would meet men I had heard of by seeing their papers in the Physical Review and so on. I had never met them before. "This is John Williams," they'd say. Then a guy stands up from a desk that is covered with blueprints, his sleeves all rolled up, and he's calling out the windows, ordering trucks and things going in different directions with building material. In other words, the experimental physicists had nothing to do until their buildings and apparatus were ready, so they just built the buildings ­­ or assisted in building the buildings.

29The theoretical physicists, on the other hand, could start working right away, so it was decided that they wouldn't live in the ranch houses, but would live up at the site. We started working immediately. There were no blackboards except for one on wheels, and we'd roll it around and Robert Serber would explain to us all the things that they'd thought of in Berkeley about the atomic bomb, and nuclear physics, and all these things. I didn't know very much about it; I had been doing other kinds of things. So I had to do an awful lot of work.

30Every day I would study and read, study and read. It was a very hectic time. But I had some luck. All the big shots except for Hans Bethe happened to be away at the time, and what Bethe needed was someone to talk to, to push his ideas against. Well, he comes in to this little squirt in an office and starts to argue, explaining his idea. I say, "No, no, you're crazy. It'll go like this." And he says, "Just a moment," and explains how he's not crazy, I'm crazy. And we keep on going like this. You see, when I hear about physics, I just think about physics, and I don't know who I'm talking to, so I say dopey things like "no, no, you're wrong," or "you're crazy." But it turned out that's exactly what he needed.

31I got a notch up on account of that, and I ended up as a group leader under Bethe with four guys under me.

32Well, when I was first there, as I said, the dormitories weren't ready. But the theoretical physicists had to stay up there anyway. The first place they put us was in an old school building ­­ a boys' school that had been there previously. I lived in a thing called the Mechanics' Lodge. We were all jammed in there in bunk beds, and it wasn't organized very well because Bob Christy and his wife had to go to the bathroom through our bedroom. So that was very uncomfortable.

33At last the dormitory was built. I went down to the place where rooms were assigned, and they said, you can pick your room now. You know what I did? I looked to see where the girls' dormitory was, and then I picked a room that looked right across ­­ though later I discovered a big tree was growing right in front of the window of that room.

34They told me there would be two people in a room, but that would only be temporary. Every two rooms would share a bathroom, and there would be double­decker bunks in each room. But I didn't want two people in the room.

35The night I got there, nobody else was there, and I decided to try to keep my room to myself. My wife was sick with TB in Albuquerque, but I had some boxes of stuff of hers. So I took out a little nightgown, opened the top bed, and threw the nightgown carelessly on it. I took out some slippers, and I threw some powder on the floor in the bathroom. I just made it look like somebody else was there. So, what happened? Well, it's supposed to be a men's dormitory, see? So I came home that night, and my pajamas are folded nicely, and put under the pillow at the bottom, and my slippers put nicely at the bottom of the bed. The lady's nightgown is nicely folded under the pillow, the bed is all fixed up and made, and the slippers are put down nicely. The powder is cleaned from the bathroom and nobody is sleeping in the upper bed.

36Next night, the same thing. When I wake up, I rumple up the top bed, I throw the nightgown on it sloppily and scatter the powder in the bathroom and so on. I went on like this for four nights until everybody was settled and there was no more danger that they would put a second person in the room. Each night, everything was set out very neatly, even though it was a men's dormitory.

37I didn't know it then, but this little ruse got me involved in politics. There were all kinds of factions there, of course ­­ the housewives' faction, the mechanics' faction, the technical peoples' faction, and so on. Well, the bachelors and bachelor girls who lived in the dormitory felt they had to have a faction too, because a new rule had been promulgated: No Women in the Men's Dorm. Well, this is absolutely ridiculous! After all, we are grown people! What kind of nonsense is this? We had to have political action.

38So we debated this stuff, and I was elected to represent the dormitory people in the town council.

39After I'd been in it for about a year and a half, I was talking to Hans Bethe about something. He was on the big governing council all this time, and I told him about this trick with my wife's nightgown and bedroom slippers. He started to laugh. "So that's how you got on the town council," he said.

40It turned out that what happened was this. The woman who cleans the rooms in the dormitory opens this door, and all of a sudden there is trouble: somebody is sleeping with one of the guys! She reports to the chief charwoman, the chief charwoman reports to the lieutenant, the lieutenant reports to the major. It goes all the way up through the generals to the governing board.

41What are they going to do? They're going to think about it, that's what! But, in the meantime, what instructions go down through the captains, down through the majors, through the lieutenants, through the chars' chief, through the charwoman? "Just put things back the way they are, clean 'em up, and see what happens." Next day, same report. For four days, they worried up there about what they were going to do. Finally they promulgated a rule: No Women in the Men's Dormitory! And that caused such a stink down below that they had to elect somebody to represent the. . .

42I would like to tell you something about the censorship that we had there. They decided to do something utterly illegal and censor the mail of people inside the United States ­­ which they have no right to do. So it had to be set up very delicately as a voluntary thing. We would all volunteer not to seal the envelopes of the letters we sent out, and it would be all right for them to open letters coming in to us; that was voluntarily accepted by us. We would leave our letters open; and they would seal them if they were OK. If they weren't OK in their opinion, they would send the letter back to us with a note that there was a violation of such and such a paragraph of our "understanding." So, very delicately amongst all these liberal­minded scientific guys, we finally got the censorship set up, with many rules. We were allowed to comment on the character of the administration if we wanted to, so we could write our senator and tell him we didn't like the way things were run, and things like that. They said they would notify us if there were any difficulties.

43So it was all set up, and here comes the first day for censorship: Telephone!

44Briiing!

45Me: "What?"

46"Please come down."

47I come down.

48"What's this?"

49"It's a letter from my father."

50"Well, what is it?"

51There's lined paper, and there's these lines going out with dots ­­ four dots under, one dot above, two dots under, one dot above, dot under dot. . .

52"What's that?"

53I said, "It's a code."

54They said, "Yeah, it's a code, but what does it say?" I said, "I don't know what it says."

55They said, "Well, what's the key to the code? How do you decipher it?" I said, "Well, I don't know."

56Then they said, "What's this?"

57I said, "It's a letter from my wife ­­ it says TJXYWZ TW1X3." "What's that?"

58I said, "Another code."

59"What's the key to it?"

60"I don't know."

61They said, "You're receiving codes, and you don't know the key?" I said, "Precisely. I have a game. I challenge them to send me a code that I can't decipher, see? So they're making up codes at the other end, and they're sending them in, and they're not going to tell me what the key is." Now one of the rules of the censorship was that they aren't going to disturb anything that you would ordinarily send in the mail. So they said, "Well, you're going to have to tell them please to send the key in with the code." I said, "I don't want to see the key!"

62They said, "Well, all right, we'll take the key out." So we had that arrangement. OK? All right. Next day I get a letter from my wife that says, "It's very difficult writing because I feel that the _____ is looking over my shoulder." And where the word was there is a splotch made with ink eradicator.

63So I went down to the bureau, and I said, "You're not supposed to touch the incoming mail if you don't like it. You can look at it, but you're not supposed to take anything out."

64They said, "Don't be ridiculous. Do you think that's the way censors work ­­ with ink eradicator? They cut things out with scissors." I said OK. So I wrote a letter back to my wife and said, "Did you use ink eradicator in your letter?" She writes back, "No, I didn't use ink eradicator in my letter, it must have been the _____" ­­ and there's a hole cut out of the paper.

65So I went back to the major who was supposed to be in charge of all this and complained. You know, this took a little time, but I felt I was sort of the representative to get the thing straightened out. The major tried to explain to me that these people who were the censors had been taught how to do it, but they didn't understand this new way that we had to be so delicate about.

66So, anyway, he said, "What's the matter, don't you think I have good will?" I said, "Yes, you have perfectly good will but I don't think you have power." Because, you see, he had already been on the job three or four days.

67He said, "We'll see about that!" He grabs the telephone, and everything is straightened out. No more is the letter cut.

68However, there were a number of other difficulties. For example, one day I got a letter from my wife and a note from the censor that said, "There was a code enclosed without the key, and so we removed it."

69So when I went to see my wife in Albuquerque that day, she said, "Well, where's all the stuff?"

70I said, "What stuff?"

71She said, "Litharge, glycerine, hot dogs, laundry." I said, "Wait a minute ­­ that was a list?" She said, "Yes."

72"That was a code," I said. "They thought it was a code­litharge, glycerine, etc." (She wanted litharge and glycerine to make a cement to fix an onyx box.) All this went on in the first few weeks before we got everything straightened out.

73Anyway, one day I'm piddling around with the computing machine, and I notice something very peculiar. If you take 1 divided by 243 you get .004115226337. . . It's quite cute: It goes a little cockeyed after 559 when you're carrying but it soon straightens itself out and repeats itself nicely. I thought it was kind of amusing.

74Well, I put that in the mail, and it comes back to me. It doesn't go through, and there's a little note: "Look at Paragraph 17B." I look at Paragraph 17B. It says, "Letters are to be written only in English, Russian, Spanish, Portuguese, Latin, German, and so forth. Permission to use any other language must be obtained in writing." And then it said, "No codes."

75So I wrote back to the censor a little note included in my letter which said that I feel that of course this cannot be a code, because if you actually do divide 1 by 243, you do, in fact, get all that, and therefore there's no more information in the number .004115226337. . . than there is in the number 243 ­­ which is hardly any information at all. And so forth. I therefore asked for permission to use Arabic numerals in my letters.

76So I got that through all right.

77There was always some kind of difficulty with the letters going back and forth.

78For example, my wife kept mentioning the fact that she felt uncomfortable writing with the feeling that the censor is looking over her shoulder. Now, as a rule, we aren't supposed to mention censorship. We aren't, but how can they tell her? So they keep sending me a note: "Your wife mentioned censorship." Certainly, my wife mentioned censorship. So finally they sent me a note that said, "Please inform your wife not to mention censorship in her letters." So I start my letter: "I have been instructed to inform you not to mention censorship in your letters." Phoom, phoooom, it comes right back! So I write, "I have been instructed to inform my wife not to mention censorship. How in the heck am I going to do it? Furthermore, why do I have to instruct her not to mention censorship? You keeping something from me?" It is very interesting that the censor himself has to tell me to tell my wife not to tell me that she's. . . But they had an answer. They said, yes, that they are worried about mail being intercepted on the way from Albuquerque, and that someone might find out that there was censorship if they looked in the mail, and would she please act much more normal.

79So I went down the next time to Albuquerque, and I talked to her and I said, "Now, look, let's not mention censorship." But we had had so much trouble that we at last worked out a code, something illegal. If I would put a dot at the end of my signature, it meant I had had trouble again, and she would move on to the next of the moves that she had concocted. She would sit there all day long, because she was ill, and she would think of things to do. The last thing she did was to send me an advertisement which she found perfectly legitimately. It said, "Send your boyfriend a letter on a jigsaw puzzle. We sell you the blank, you write the letter on it, take it all apart, put it in a little sack, and mail it." I received that one with a note saying, "We do not have time to play games. Please instruct your wife to confine herself to ordinary letters." Well, we were ready with the one more dot, but they straightened out just in time and we didn't have to use it. The thing we had ready for the next one was that the letter would start, "I hope you remembered to open this letter carefully because I have included the Pepto­Bismol powder for your stomach as we arranged." It would be a letter full of powder. In the office we expected they would open it quickly, the powder would go all over the floor, and they would get all upset because you are not supposed to upset anything. They'd have to gather up all this Pepto­Bismol. . . But we didn't have to use that one.

80As a result of all these experiences with the censor, I knew exactly what could get through and what could not get through. Nobody else knew as well as I. And so I made a little money out of all of this by making bets.

81One day I discovered that the workmen who lived further out and wanted to come in were too lazy to go around through the gate, and so they had cut themselves a hole in the fence. So I went out the gate, went over to the hole and came in, went out again, and so on, until the sergeant at the gate began to wonder what was happening. How come this guy is always going out and never coming in? And, of course, his natural reaction was to call the lieutenant and try to put me in jail for doing this. I explained that there was a hole.

82You see, I was always trying to straighten people out. And so I made a bet with somebody that I could tell about the hole in the fence in a letter, and mail it out. And sure enough, I did. And the way I did it was I said, You should see the way they administer this place (that's what we were allowed to say). There's a hole in the fence seventy­one feet away from such­and­such a place, that's this size and that size, that you can walk through.

83Now, what can they do? They can't say to me that there is no such hole. I mean, what are they going to do? It's their own hard luck that there's such a hole. They should fix the hole. So I got that one through.

84I also got through a letter that told about how one of the boys who worked in one of my groups, John Kemeny, had been wakened up in the middle of the night and grilled with lights in front of him by some idiots in the army there because they found out something about his father, who was supposed to be a communist or something. Kemeny is a famous man now.

85There were other things. Like the hole in the fence, I was always trying to point these things out in a non­direct manner. And one of the things I wanted to point out was this ­­ that at the very beginning we had terribly important secrets; we'd worked out lots of stuff about bombs and uranium and how it worked, and so on; and all this stuff was in documents that were in wooden filing cabinets that had little, ordinary, common padlocks on them. Of course, there were various things made by the shop, like a rod that would go down and then a padlock to hold it, but it was always just a padlock. Furthermore, you could get the stuff out without even opening the padlock. You just tilt the cabinet over backwards. The bottom drawer has a little rod that's supposed to hold the papers together, and there's a long wide hole in the wood underneath. You can pull the papers out from below.

86So I used to pick the locks all the time and point out that it was very easy to do.

87And every time we had a meeting of everybody together, I would get up and say that we have important secrets and we shouldn't keep them in such things; we need better locks.

88One day Teller got up at the meeting, and he said to me, "I don't keep my most important secrets in my filing cabinet; I keep them in my desk drawer. Isn't that better?" I said, "I don't know. I haven't seen your desk drawer." He was sitting near the front of the meeting, and I'm sitting further back. So the meeting continues, and I sneak out and go down to see his desk drawer.

89I don't even have to pick the lock on the desk drawer. It turns out that if you put your hand in the back, underneath, you can pull out the paper like those toilet paper dispensers. You pull out one, it pulls another, it pulls another... I emptied the whole damn drawer, put everything away to one side, and went back upstairs.

90The meeting was just ending, and everybody was coming out, and I joined the crew and ran to catch up with Teller, and I said, "Oh, by the way, let me see your desk drawer."

91"Certainly," he said, and he showed me the desk.

92I looked at it and said, "That looks pretty good to me. Let's see what you have in there."

93"I'll be very glad to show it to you," he said, putting in the key and opening the drawer. "If," he said, "you hadn't already seen it yourself." The trouble with playing a trick on a highly intelligent man like Mr. Teller is that the time it takes him to figure out from the moment that he sees there is something wrong till he understands exactly what happened is too damn small to give you any pleasure!

94Some of the special problems I had at Los Alamos were rather interesting. One thing had to do with the safety of the plant at Oak Ridge, Tennessee. Los Alamos was going to make the bomb, but at Oak Ridge they were trying to separate the isotopes of uranium ­­ uranium 238 and uranium 235, the explosive one. They were just beginning to get infinitesimal amounts from an experimental thing of 235, and at the same time they were practicing the chemistry. There was going to be a big plant, they were going to have vats of the stuff, and then they were going to take the purified stuff and repurify and get it ready for the next stage. (You have to purify it in several stages.) So they were practicing on the one hand, and they were just getting a little bit of U235 from one of the pieces of apparatus experimentally on the other hand. And they were trying to learn how to assay it, to determine how much uranium 235 there is in it. Though we would send them instructions, they never got it right.

95So finally Emil Segre said that the only possible way to get it right was for him to go down there and see what they were doing. The army people said, "No, it is our policy to keep all the information of Los Alamos at one place." The people in Oak Ridge didn't know anything about what it was to be used for; they just knew what they were trying to do. I mean the higher people knew they were separating uranium, but they didn't know how powerful the bomb was, or exactly how it worked or anything. The people underneath didn't know at all what they were doing. And the army wanted to keep it that way. There was no information going back and forth. But Segre insisted they'd never get the assays right, and the whole thing would go up in smoke. So he finally went down to see what they were doing, and as he was walking through he saw them wheeling a tank carboy of water, green water ­­ which is uranium nitrate solution.

96He said, "Uh, you're going to handle it like that when it's purified too? Is that what you're going to do?"

97They said, "Sure ­­ why not?"

98"Won't it explode?" he said.

99Huh! Explode?

100Then the army said, "You see! We shouldn't have let any information get to them!

101Now they are all upset. "

102It turned out that the army had realized how much stuff we needed to make a bomb ­­ twenty kilograms or whatever it was ­­ and they realized that this much material, purified, would never be in the plant, so there was no danger. But they did not know that the neutrons were enormously more effective when they are slowed down in water. In water it takes less than a tenth ­­ no, a hundredth ­­ as much material to make a reaction that makes radioactivity. It kills people around and so on. It was very dangerous, and they had not paid any attention to the safety at all.

103So a telegram goes from Oppenheimer to Segre: "Go through the entire plant.

104Notice where all the concentrations are supposed to be, with the process as they designed it. We will calculate in the meantime how much material can come together before there's an explosion. "

105Two groups started working on it. Christy's group worked on water solutions and my group worked on dry powder in boxes. We calculated about how much material they could accumulate safely. And Christy was going to go down and tell them all at Oak Ridge what the situation was, because this whole thing is broken down and we have to go down and tell them now. So I happily gave all my numbers to Christy and said, you have all the stuff, so go. Christy got pneumonia; I had to go.

106I had never traveled on an airplane before. They strapped the secrets in a little thing on my back! The airplane in those days was like a bus, except the stations were further apart. You stopped off every once in a while to wait.

107There was a guy standing there next to me swinging a chain, saying something like, "It must be terribly difficult to fly without a priority on airplanes these days." I couldn't resist. I said, "Well, I don't know. I have a priority." A little bit later he tried again. "There are some generals coming. They are going to put off some of us number threes."

108"It's all right," I said. "I'm a number two." He probably wrote to his congressman ­­ if he wasn't a congressman himself ­­ saying, "What are they doing sending these little kids around with number two priorities in the middle of the war?"

109At any rate, I arrived at Oak Ridge. The first thing I did was have them take me to the plant, and I said nothing. I just looked at everything. I found out that the situation was even worse than Segre reported, because he noticed certain boxes in big lots in a room, but he didn't notice a lot of boxes in another room on the other side of the same wall ­­ and things like that. Now, if you have too much stuff together, it goes up, you see.

110So I went through the entire plant. I have a very bad memory, but when I work intensively I have a good short­term memory, and so I could remember all kinds of crazy things like building 90­207, vat number so­and­so, and so forth.

111I went to my room that night, and went through the whole thing, explained where all the dangers were, and what you would have to do to fix this. It's rather easy. You put cadmium in solutions to absorb the neutrons in the water, and you separate the boxes so they are not too dense, according to certain rules.

112The next day there was going to be a big meeting. I forgot to say that before I left Los Alamos Oppenheimer said to me, "Now, the following people are technically able down there at Oak Ridge: Mr. Julian Webb, Mr. So­and­so, and so on. I want you to make sure that these people are at the meeting, that you tell them how the thing can be made safe, so that they really understand." I said, "What if they're not at the meeting? What am I supposed to do?" He said, "Then you should say: Los Alamos cannot accept the responsibility for the safety of the Oak Ridge plant unless. . .!" I said, "You mean me, little Richard, is going to go in there and say ­­?" He said, "Yes, little Richard, you go and do that." I really grew up fast!

113When I arrived, sure enough, the big shots in the company and the technical people that I wanted were there, and the generals and everyone who was interested in this very serious problem. That was good because the plant would have blown up if nobody had paid attention to this problem.

114There was a Lieutenant Zumwalt who took care of me. He told me that the colonel said I shouldn't tell them how the neutrons work and all the details because we want to keep things separate, so just tell them what to do to keep it safe.

115I said, "In my opinion it is impossible for them to obey a bunch of rules unless they understand how it works. It's my opinion that it's only going to work if I tell them, and Los Alamos cannot accept the responsibility for the safety of the Oak Ridge plant unless they are fully informed as to how it works!" It was great. The lieutenant takes me to the colonel and repeats my remark. The colonel says, "Just five minutes," and then he goes to the window and he stops and thinks. That's what they're very good at ­­ making decisions. I thought it was very remarkable how a problem of whether or not information as to how the bomb works should be in the Oak Ridge plant had to be decided and could be decided in five minutes.

116So I have a great deal of respect for these military guys, because I never can decide anything very important in any length of time at all.

117In five minutes he said, "All right, Mr. Feynman, go ahead." I sat down and I told them all about neutrons, how they worked, da da, ta ta ta, there are too many neutrons together, you've got to keep the material apart, cadmium absorbs, and slow neutrons are more effective than fast neutrons, and yak yak ­­ all of which was elementary stuff at Los Alamos, but they had never heard of any of it, so I appeared to be a tremendous genius to them.

118The result was that they decided to set up little groups to make their own calculations to learn how to do it. They started to redesign plants, and the designers of the plants were there, the construction designers, and engineers, and chemical engineers for the new plant that was going to handle the separated material.

119They told me to come back in a few months, so I came back when the engineers had finished the design of the plant. Now it was for me to look at the plant.

120How do you look at a plant that isn't built yet? I don't know. Lieutenant Zumwalt, who was always coming around with me because I had to have an escort everywhere, takes me into this room where there are these two engineers and a loooooong table covered with a stack of blueprints representing the various floors of the proposed plant.

121I took mechanical drawing when I was in school, but I am not good at reading blueprints. So they unroll the stack of blueprints and start to explain it to me, thinking I am a genius. Now, one of the things they had to avoid in the plant was accumulation.

122They had problems like when there's an evaporator working, which is trying to accumulate the stuff, if the valve gets stuck or something like that and too much stuff accumulates, it'll explode. So they explained to me that this plant is designed so that if any one valve gets stuck nothing will happen. It needs at least two valves everywhere.