Well, there was also some other things. I was always trying to straighten them out, like point out the holes in the fence and so forth, but I was always trying to point these things out in a non-direct 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 uranium, how it worked, and all this stuff was in documents that were in filing cabinets that were made out of wood that had on them little ordinary, common padlocks. Various things made by the shop were on the cabinets, 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, without even opening the padlock, out of these wooden cabinets; you just tilt it over backwards and the bottom drawer, you know, has a little rod that’s supposed to hold it. And there’s a hole in the wood underneath; you can pull the papers out from below. So I used to pick the locks all the time and point out that it was very easy to do. And every time we had a meeting of the whole group, everybody together, I would get up and I’d say that we have important secrets and we shouldn’t keep them in such things. These were such poor locks. We need better locks. And so one day Teller got up at the meeting, and said to me, “Well, 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.” Well, he’s sitting near the front of the meeting and I’m sitting further back. So the meeting continues and I sneak out of the meeting and I go down to see his desk drawer. OK? I 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, took everything out, and put it away to one side and then went up on the higher floor and came back. The meeting is just ending and everybody is just coming out and I join the crew like this, you see, walking along with it, and run up to catch up with Teller, and say, “Oh, by the way, let me see your desk drawer.” So he says, “Certainly,” so we walk into his office and he shows me the desk and I look at it and say that looks pretty good to me. I said “Let’s see what you have in there.” “I’d be very glad to show it to you,” he says, putting in the key and opening the drawer, “if you hadn’t already seen it yourself.” The trouble with playing a trick on a highly intelligent man like Mr. Teller is 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!
Well, I had a lot of other fun with the safes but it has nothing to do with Los Alamos, so I won’t discuss it further. I want to tell about some of the problems, special problems, that I had that are rather interesting. One thing had to do with the safety of the plant at Oak Ridge. 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 236, 235, the latter one, which was the explosive one, all right? So, they were just beginning to get infinitesimal amounts from an experimental thing, of 235, and at the same time they were practicing. There was a big plant, they were going to have vats of the stuff, chemicals, and 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 the chemistry on the one hand and they were just getting a little bit 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, and we would send them instructions and they never got it right. So finally Segrè* said that the only possible way to get it right was that he’d have to go down there to see what they’re doing, to understand why the assay was wrong. The Army people said no, it is our policy to keep all the information of Los Alamos at one place, and that the people in Oak Ridge should not know anything about what it was 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. And 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 Segrè finally insisted on it, that it was important. They’d never get the assays right, the whole thing would go up in smoke. So Segrè 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; the green water is uranium nitrate. He says, “You’re going to handle it like that when it’s purified too? Is that what you’re going to do?” They said, “Sure, why not?” “Won’t it explode?” he says. “Huh?! Explode!??” And so the Army said, “You see, we shouldn’t have let any information go across!” Well, it turned out that the Army had realized how much stuff we needed to make a bomb, 20 kilograms or whatever it was, and they realized that that much material would never, 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. And so in water it takes less than a tenth, no a hundredth, very much less material to make a reaction which makes radioactivity. It doesn’t make a big explosion, but it makes radioactivity, it kills people all around and so on. So, it was very dangerous and they had not paid any attention to the safety at all.
So a telegram goes from Oppenheimer to Segrè: Go through the entire plant, notice 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. And so two groups started working on it. Christie’s group worked on water solutions and I worked on dry powder in boxes, my group. And we calculated about how much material. And Christie was going to go down and tell them all at Oak Ridge what the situation was. And so I happily gave all my numbers to Christie, and said, you have all the stuff, and go. Christie got pneumonia; I had to go. I never traveled on an airplane before; I traveled on an airplane. They strapped the secrets, with a little thing with a belt, on my back! The airplane in those days was like a bus. You stop off every once in a while except the stations were further apart. You stop off to wait. There’s a guy standing there next to me with a keychain, swinging it, 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 some generals come aboard and they are going to put out some of us number 3s. It’s all right, I’m a number 2. That passenger probably wrote to his congressman, if he wasn’t a congressman himself, saying, what are they doing sending these little kids around with number priorities in the middle of the war? At any rate, I arrived there. 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 Segrè reported because he was confused at the first time through. He noticed certain boxes in big lots but he didn’t notice other boxes in another room in a big lot, but it was the same room on the other side. And things like that. So if you have too much stuff together it goes up, you see. So I went through the entire plant and, I have a very bad memory but when I work intensively, I have a good short-term memory and so I could remember all kinds of crazy things like building ninety-two-oh-seven, vat number so and so, and so forth. I went home that night and I went through the whole thing explaining where all the dangers were, 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, you separate the boxes so they are not too dense, too much uranium together and so on, according to certain rules. And so I used all the examples, worked out all the examples and how the process of freezing worked. I felt that you couldn’t make the plant safe unless you knew how it worked. So the next day there was going to be a big meeting.
Oh, I forgot to say, before I left, Oppenheimer said to me, �
�Now,” he said, “when you go, the following people are technically able down there at Oak Ridge: Mr. Julian Webb, Mr. So and so, and so on. I want you to make sure that these people are at the meeting, that you tell them how the thing, you know, the safety, that they really understand–they’re in charge.” 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’s, going to go in there and say. . . .?” He says, “Yes, little Richard, you go and do that.” I really grew up fast! So when I arrived, sure enough, I arrived there and the meeting was the next day and all these people from the company, the big shots in the company and the technical people that I wanted were there, and the generals and so forth, that were interested in the problems, organizing everything. It was a big meeting about this very serious problem of safety, because the plant would never work. It would have blown up, I swear it would have, if nobody had paid attention. So there was a lieutenant who took care of me. He told me that the colonel said that I shouldn’t tell them how the neutrons work and all the details because we want to keep the things separate. Just tell them what to do to keep it safe. I said, in my opinion, it is impossible for them to understand or to obey a bunch of rules if they don’t understand, unless they understand how it works. So 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. So he goes to the colonel. “Give me just five minutes,” the colonel says. He goes to the window and he stops and thinks and that’s what they’re very good at. They are 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. So 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.
So, in five minutes, he says, all right, Mr. Feynman, go ahead. So 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 got to keep the material apart, cadmium absorbs, and slow neutrons are more effective than fast neutrons, and yak yak–all stuff which was elementary primer stuff at Los Alamos, but they had never heard of any of it, so I turned out to be a tremendous genius to them. I was a god coming down from the sky! There was all these phenomena that were not understood and never heard of before, I knew all about it, I could give them facts and numbers and everything else. So, from being rather primitive back there at Los Alamos, I was a super genius at the other end. Well, the result was that they decided, they made little groups, to make their own calculations to learn how to do it. They started to redesign plants. The designers of the plants were there, the construction designers, engineers, chemical engineers for the new plant that was going to handle the separated material were there. And other people were there. And I went away again. They told me to come back in a few months; they were going to redesign their plant for the separation.
So I came back in a few months, a month or so, and Stone and Webster Company, the engineers, had finished the design of the plant and now it was for me to look at the plant. OK? How do you look at a plant that ain’t built yet? I don’t know. So I go into this room with these fellows. There was always a Lieutenant Zumwalt that was always coming around with me, taking care of me, you know; I had to have an escort everywhere. So he goes with me, he takes me into this room and there are these two engineers and a loooooooong table, great big long table, tremendous table, covered with a blueprint that’s as big as a table; not one blueprint, but a stack of blueprints. I took mechanical drawing when I was in school, but I wasn’t too good at reading blueprints. So they start to explain it to me because they thought I was a genius. And they start out, “Mr. Feynman, we would like you to understand, the plant is so designed, you see one of the things we had to avoid was accumulation.” Problems like–there’s an evaporator working which is trying to accumulate the stuff; if the valve gets stuck or something like that and they accumulate too much stuff, it’ll explode. So they explained to me that this plant is designed so that no one valve, if any one valve gets stuck nothing will happen. It needs at least two valves everywhere. So then they explain how it works. The carbon tetrachloride comes in here, the uranium nitrate from here comes in here, it goes up and down, it goes up through the floor, comes up through the pipes, coming up from the second floor, bluuuuurp, from the blueprints, down, up, down, up, very fast talking explaining the very, very complicated chemical plant. I’m completely dazed, worse, I don’t know what the symbols on the blueprint mean! There is some kind of a thing that at first I think it’s a window. It’s a square with a little cross in the middle, all over the damn place. Lines with this damn square, lines with the damn square. I think it’s a window; no, it can’t be a window, ’cause it ain’t always at the edge. I want to ask them what it is. You must have been in a situation like this–you didn’t ask them right away, right away it would have been OK. But they’ve been talking a little bit too long. You hesitated too long. If you ask them now they’ll say, what are you wasting my time all this time for? I don’t know what to do; I think to myself, often in my life I have been lucky. You are not going to believe this story, but I swear it’s absolutely true; it’s such sensational luck. I thought what am I going to do, what am I going to do????? I got an idea. Maybe it’s a valve? So, in order to find out whether it’s a valve or not I take my finger and I put it down in the middle of one of the blueprints on page number 3 down in the end and I said, “What happens if this valve gets stuck?” figuring they’re going to say, “That’s not a valve, sir, that’s a window.” So one looks at the other and says, “Well, if that valve gets stuck,” and they go up and down on the blueprint, up and down, the other guy up and down, back and forth, back and forth, and they both look at each other and they turn around to me and they open their mouths–“You’re absolutely right, sir.” So they roll up the blueprints and away they went and we walked out. And Lt. Zumwalt, who had been following me all the way through, said, “You’re a genius. I got the idea you were a genius when you went through the plant once and you could tell them about evaporator C-21 in building 90-207 the next morning,” he says, “but what you have just done is so fantastic, I want to know how, how do you do something like that?” I told him, you try to find out whether it’s a valve or not.
Well, another kind of problem that I worked on was this. We had to do lots of calculations and we did them on Marchant calculating machines. By the way, just to give you an idea of what Los Alamos was like, we had these Marchant computers. I don’t know if you know what they look like, hand calculators with numbers and you push them, and they multiply, divide, add, and so on. Not like they do easy now, but hard; they were mechanical gadgets. And they had to be sent back to the factory to be repaired. We didn’t have a special man to do it, which was the standard way, and so they would always be sent to the factory. Pretty soon you were running out of machines. So I and a few other fellows started to take the covers off. We weren’t supposed to–the rules “You take the covers off, we cannot be responsible . . .” So we took the covers off and we had a nice series of lessons. Like the first one we took the cover off, there was a shaft with a hole in it and a spring which was hanging this way, and obviously the spring went in the hole–so that was easy. So anyway, we got like a series of lessons, by God, on how to fix them and we got better and better and we made more and more elaborate repairs. When we got something too complicated we sent it out, back to the factory, but we’d do the easy ones and kept the things going. I also did some typewriters. I ended up doing all the computers; the other fellows quit on me. I did a few typewriters. There was a guy in the machine shop who was better than I was and he took care of typewriters; I took care of adding machines. However, we deci
ded that the big problem was to figure out exactly what happened during the bomb’s explosion when you push the stuff in by an explosion and then it goes out again. Exactly what happens, so you can figure out exactly how much energy was released and so on, required much more calculating than we were capable of. And a rather clever fellow by the name of Stanley Frankle realized that it could possibly be done on IBM machines. The IBM company had machines for business purposes, adding machines that are called tabulators for listing sums and a multiplier, just a machine, a big box, you put cards in and it would take two numbers from a card and multiply it and print it on a card. And then there were collators and sorters and so on. So he decided, he’d figured out a nice program. If we got enough of these machines in a room, we would take the cards and put them through a cycle; everybody who does numerical calculations now knows exactly what I’m talking about, but this was kind of a new thing: mass production with machines.
The Pleasure of Finding Things Out Page 8