“Surely You’re Joking, Mr. Feynman”: Adventures of a Curious Character

Fizzled Fuses

When the war began in Europe but had not yet been declared in the United States, there was a lot of talk about getting ready and being patriotic. The newspapers had big articles on businessmen volunteering to go to Plattsburg, New York, to do military training, and so on.

I began to think I ought to make some kind of contribution, too. After I finished up at MIT, a friend of mine from the fraternity, Maurice Meyer, who was in the Army Signal Corps, took me to see a colonel at the Signal Corps offices in New York.

“I’d like to aid my country sir, and since I’m technically minded, maybe there’s a way I could help.”

“Well, you’d better just go up to Plattsburg to boot camp and go through basic training. Then we’ll be able to use you,” the colonel said.

“But isn’t there some way to use my talent more directly?”

“No; this is the way the army is organized. Go through the regular way.”

I went outside and sat in the park to think about it. I thought and thought: Maybe the best way to make a contribution is to go along with their way. But fortunately I thought a little more, and said, “To hell with it! I’ll wait awhile. Maybe something will happen where they can use me more effectively”

I went to Princeton to do graduate work, and in the spring I went once again to the Bell Labs in New York to apply for a summer job. I loved to tour the Bell Labs. Bill Shockley the guy who invented transistors, would show me around. I remember somebody’s room where they had marked a window: The George Washington Bridge was being built, and these guys in the lab were watching its progress. They had plotted the original curve when the main cable was first put up, and they could measure the small differences as the bridge was being suspended from it, as the curve turned into a parabola. It was just the kind of thing I would like to be able to think of doing. I admired those guys; I was always hoping I could work with them one day.

Some guys from the lab took me out to this seafood restaurant for lunch, and they were all pleased that they were going to have oysters. I lived by the ocean and I couldn’t look at this stuff; I couldn’t eat fish, let alone oysters.

I thought to myself, “I’ve gotta be brave. I’ve gotta eat an oyster.”

I took an oyster, and it was absolutely terrible. But I said to myself, “That doesn’t really prove you’re a man. You didn’t know how terrible it was gonna be. It was easy enough when it was uncertain.”

The others kept talking about how good the oysters were, so I had another oyster, and that was really harder than the first one.

This time, which must have been my fourth or fifth time touring the Bell Labs, they accepted me. I was very happy. In those days it was hard to find a job where you could be with other scientists.

But then there was a big excitement at Princeton. General Trichel from the army came around and spoke to us: “We’ve got to have physicists! Physicists are very important to us in the army! We need three physicists!”

You have to understand that, in those days, people hardly knew what a physicist was. Einstein was known as a mathematician, for instance—so it was rare that anybody needed physicists. I thought, “This is my opportunity to make a contribution,” and I volunteered to work for the army.

I asked the Bell Labs if they would let me work for the army that summer, and they said they had war work, too, if that was what I wanted. But I was caught up in a patriotic fever and lost a good opportunity. It would have been much smarter to work in the Bell Labs. But one gets a little silly during those times.

I went to the Frankfort Arsenal, in Philadelphia, and worked on a dinosaur: a mechanical computer for directing artillery. When airplanes flew by the gunners would watch them in a telescope, and this mechanical computer, with gears and cams and so forth, would try to predict where the plane was going to be. It was a most beautifully designed and built machine, and one of the important ideas in it was non-circular gears—gears that weren’t circular, but would mesh anyway. Because of the changing radii of the gears, one shaft would turn as a function of the other. However, this machine was at the end of the line. Very soon afterwards, electronic computers came in.

After saying all this stuff about how physicists were so important to the army the first thing they had me doing was checking gear drawings to see if the numbers were right. This went on for quite a while. Then, gradually the guy in charge of the department began to see I was useful for other things, and as the summer went on, he would spend more time discussing things with me.

One mechanical engineer at Frankfort was always trying to design things and could never get everything right. One time he designed a box full of gears, one of which was a big, eight-inch-diameter gear wheel that had six spokes. The fella says excitedly “Well, boss, how is it? How is it?”

“Just fine!” the boss replies. “All you have to do is specify a shaft passer on each of the spokes, so the gear wheel can turn!” The guy had designed a shaft that went right between the spokes!

The boss went on to tell us that there was such a thing as a shaft passer (I thought he must have been joking). It was invented by the Germans during the war to keep the British minesweepers from catching the cables that held the German mines floating under water at a certain depth. With these shaft passers, the German cables could allow the British cables to pass through as if they were going through a revolving door. So it was possible to put shaft passers on all the spokes, but the boss didn’t mean that the machinists should go to all that trouble; the guy should instead just redesign it and put the shaft somewhere else.

Every once in a while the army sent down a lieutenant to check on how things were going. Our boss told us that since we were a civilian section, the lieutenant was higher in rank than any of us. “Don’t tell the lieutenant anything,” he said. “Once he begins to think he knows what we’re doing, he’ll be giving us all kinds of orders and screwing everything up.

By that time I was designing some things, but when the lieutenant came by I pretended I didn’t know what I was doing, that I was only following orders.

“What are you doing here, Mr. Feynman?”

“Well, I draw a sequence of lines at successive angles, and then I’m supposed to measure out from the center different distances according to this table, and lay it out.

“Well, what is it?”

“I think it’s a cam.” I had actually designed the thing, but I acted as if somebody had just told me exactly what to do.

The lieutenant couldn’t get any information from anybody and we went happily along, working on this mechanical computer, without any interference.

One day the lieutenant came by and asked us a simple question: “Suppose that the observer is not at the same location as the gunner—how do you handle that?”

We got a terrible shock. We had designed the whole business using polar coordinates, using angles and the radius distance. With X and Y coordinates, it’s easy to correct for a displaced observer. It’s simply a matter of addition or subtraction. But with polar coordinates, it’s a terrible mess!

So it turned out that this lieutenant whom we were trying to keep from telling us anything ended up telling us something very important that we had forgotten in the design of this device: the possibility that the gun and the observing station are not at the same place! It was a big mess to fix it.

Near the end of the summer I was given my first real design job: a machine that would make a continuous curve out of a set of points—one point coming in every fifteen seconds—from a new invention developed in England for tracking airplanes, called “radar.” It was the first time I had ever done any mechanical designing, so I was a little bit frightened.

I went over to one of the other guys and said, “You’re a mechanical engineer; I don’t know how to do any mechanical engineering, and I just got this job

“There’s nothin’ to it,” he said. “Look, I’ll show you. There’s two rules you need to know to design these machines. First, the friction in every bearing is so-and-so much, and in every gear junction, so-and-so much. From that, you can figure out how much force you need to drive the thing. Second, when you have a gear ratio, say 2 to 1, and you are wondering whether you should make it 10 to 5 or 24 to 12 or 48 to 24, here’s how to decide: You look in the Boston Gear Catalogue, and select those gears that are in the middle of the list. The ones at the high end have so many teeth they’re hard to make. If they could make gears with even finer teeth, they’d have made the list go even higher. The gears at the low end of the list have so few teeth they break easy. So the best design uses gears from the middle of the list.”

I had a lot of fun designing that machine. By simply selecting the gears from the middle of the list and adding up the little torques with the two numbers he gave me, I could be a mechanical engineer!

The army didn’t want me to go back to Princeton to work on my degree after that summer. They kept giving me this patriotic stuff, and offered a whole project that I could run, if I would stay.

The problem was to design a machine like the other one—what they called a director—but this time I thought the problem was easier, because the gunner would be following behind in another airplane at the same altitude. The gunner would set into my machine his altitude and an estimate of his distance behind the other airplane. My machine would automatically tilt the gun up at the correct angle and set the fuse.

As director of this project, I would be making trips down to Aberdeen to get the firing tables. However, they already had some preliminary data. I noticed that for most of the higher altitudes where these airplanes would be flying, there wasn’t any data. So I called up to find out why there wasn’t any data and it turned out that the fuses they were going to use were not clock fuses, but powder-train fuses, which didn’t work at those altitudes—they fizzled out in the thin air.

I thought I only had to correct the air resistance at different altitudes. Instead, my job was to invent a machine that would make the shell explode at the right moment, when the fuse won’t burn!

I decided that was too hard for me and went back to Princeton.

Testing Bloodhounds

When I was at Los Alamos and would get a little time off, I would often go visit my wife, who was in a hospital in Albuquerque, a few hours away. One time I went to visit her and couldn’t go in right away so I went to the hospital library to read.

I read an article in Science about bloodhounds, and how they could smell so very well. The authors described the various experiments that they did—the bloodhounds could identify which items had been touched by people, and so on—and I began to think: It is very remarkable how good bloodhounds are at smelling, being able to follow trails of people, and so forth, but how good are we, actually?

When the time came that I could visit my wife, I went to see her, and I said, “We’re gonna do an experiment. Those Coke bottles over there (she had a six-pack of empty Coke bottles that she was saving to send out)—now you haven’t touched them in a couple of days, right?”

“That’s right.”

I took the six-pack over to her without touching the bottles, and said, “OK. Now I’ll go out, and you take out one of the bottles, handle it for about two minutes, and then put it back. Then I’ll come in, and try to tell which bottle it was.”

So I went out, and she took out one of the bottles and handled it for quite a while—lots of time, because I’m no bloodhound! According to the article, they could tell if you just touched it.

Then I came back, and it was absolutely obvious! I didn’t even have to smell the damn thing, because, of course, the temperature was different. And it was also obvious from the smell. As soon as you put it up near your face, you could smell it was dampish and warmer. So that experiment didn’t work because it was too obvious.

Then I looked at the bookshelf and said, “Those books you haven’t looked at for a while, right? This time, when I go out, take one book off the shelf, and just open it—that’s all—and close it again; then put it back.”

So I went out again, she took a book, opened it and closed it, and put it back. I came in—and nothing to it! It was easy. You just smell the books. It’s hard to explain, because we’re not used to saying things about it. You put each book up to your nose and sniff a few times, and you can tell. It’s very different. A book that’s been standing there a while has a dry uninteresting kind of smell. But when a hand has touched it, there’s a dampness and a smell that’s very distinct.

We did a few more experiments, and I discovered that while bloodhounds are indeed quite capable, humans are not as incapable as they think they are: it’s just that they carry their nose so high off the ground!

(I’ve noticed that my dog can correctly tell which way I’ve gone in the house, especially if I’m barefoot, by smelling my footprints. So I tried to do that: I crawled around the rug on my hands and knees, sniffing, to see if I could tell the difference between where I walked and where I didn’t, and I found it impossible. So the dog is much better than I am.)

Many years later, when I was first at Caltech, there was a party at Professor Bacher’s house, and there were a lot of people from Caltech. I don’t know how it came up, but I was telling them this story about smelling the bottles and the books. They didn’t believe a word, naturally because they always thought I was a faker. I had to demonstrate it.

We carefully took eight or nine books off the shelf without touching them directly with our hands, and then I went out. Three different people touched three different books: they picked one up, opened it, closed it, and put it back.

Then I came back, and smelled everybody’s hands, and smelled all the books—I don’t remember which I did first—and found all three books correctly; I got one person wrong.

They still didn’t believe me; they thought it was some sort of magic trick. They kept trying to figure out how I did it. There’s a famous trick of this kind, where you have a confederate in the group who gives you signals as to what it is, and they were trying to figure out who the confederate was. Since then I’ve often thought that it would be a good card trick to take a deck of cards and tell someone to pick a card and put it back, while you’re in the other room. You say, “Now I’m going to tell you which card it is, because I’m a bloodhound: I’m going to smell all these cards and tell you which card you picked.” Of course, with that kind of patter, people wouldn’t believe for a minute that that’s what you were actually doing!

People’s hands smell very different—that’s why dogs can identify people; you have to try it! All hands have a sort of moist smell, and a person who smokes has a very different smell on his hands from a person who doesn’t; ladies often have different kinds of perfumes, and so on. If somebody happened to have some coins in his pocket and happened to be handling them, you can smell that.

Los Alamos from Below [1]

When 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.

I 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.

He 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.”

So 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.

By 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.

It 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. What 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.

All 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 six-week 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.

One 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. Then 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.

So 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.

It 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.

The 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.

I 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.

It 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. But 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.

I 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.”

There 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.

When he came back to us, we were all ready to go and we were getting impatient. So they all got together and decided we’d go out there anyway even though it wasn’t ready.

We 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.

We 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.

So 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.

Well, 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. The 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.

When 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.

When 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.

The 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.

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

Well, 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.

At 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.

They 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 double-decker bunks in each room. But I didn’t want two people in the room.

The 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.

Next 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.

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

After 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.

It 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.

What 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 …

I 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 liberal-minded 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.

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

Me: “What?”

“Please come down.” I come down.

“What’s this?”

“It’s a letter from my father.”

“Well, what is it?”

There’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 …

“What’s that?”

I said, “It’s a code.”

They said, “Yeah, it’s a code, but what does it say?”

I said, “I don’t know what it says.”

They said, “Well, what’s the key to the code? How do you decipher it?”

I said, “Well, I don’t know.”

Then they said, “What’s this?”

I said, “It’s a letter from my wife—it says TJXYWZ TW1X3.”

“What’s that?”

I said, “Another code.”

“What’s the key to it?”

“I don’t know.”

They 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!”

They 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.

So 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.”

They 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.

So 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.

So, 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.

He said, “We’ll see about that!” He grabs the telephone, and everything is straightened out. No more is the letter cut.

However, 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.”

So when I went to see my wife in Albuquerque that day, she said, “Well, where’s all the stuff?”

I said, “What stuff?”

She said, “Litharge, glycerine, hot dogs, laundry.”

I said, “Wait a minute—that was a list?”

She said, “Yes.”

“That was a code,” I said. “They thought it was a code—litharge, 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. An way, 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.

Well, 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.”

So 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. So I got that through all right.

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

So 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 Pepto-Bismol 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 Pepto-Bismol … But we didn’t have to use that one.

As 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.

One 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.

You 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 seventy-one feet away from such-and-such a place, that’s this size and that size, that you can walk through.

Now, 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.

I 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.

There were other things. Like the hole in the fence, 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 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.

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 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. One 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.

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, put everything away to one side, and went back upstairs.

The 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.”

“Certainly,” he said, and he showed me the desk.

I looked at it and said, “That looks pretty good to me. Let’s see what you have in there.”

“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!

Some 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.

So 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.

He said, “Uh, 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 said.

Huh! Explode?

Then the army said, “You see! We shouldn’t have let any information get to them! Now they are all upset.”

It 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.

So a telegram goes from Oppenheimer to Segre: “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.”

Two 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.

I 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.

There 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.”

“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?”

At 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.

So 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 90-207, vat number so-and-so, and so forth.

I 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.

The 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. 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 can he 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!

When 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.

There 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.

I 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. 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.

In 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.

The 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.

They 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.

How 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.

I 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. They 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.

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–going through the stack of blueprints, downup-down-up, talking very fast, 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 is a window. It’s a square with a little cross in the middle, all over the damn place. I think it’s a window, but no, it can’t be a window, because it isn’t always at the edge. I want to ask them what it is.

You must have been in a situation like this when you didn’t ask them right away. Right away it would have been OK. But now 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?”

What am I going to do? I get an idea. Maybe it’s a valve.

I take my finger and I put it down on one of the mysterious little crosses in the middle of one of the blueprints on page three, and I say “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 he goes up and down on the blueprint, up and down, the other guy goes up and down, back and forth, back and forth, and they both look at each other. They turn around to me and they open their mouths like astonished fish and say “You’re absolutely right, sir.”

So they rolled up the blueprints and away they went and we walked out. And Mr. 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 that?”

I told him you try to find out whether it’s a valve or not.

Another kind of problem 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—hand calculators with numbers. You push them, and they multiply divide, add, and so on, but not easy like they do now. They were mechanical gadgets, failing often, and they had to be sent back to the factory to be repaired. Pretty soon you were running out of machines. A few of us started to take the covers off. (We weren’t supposed to. The rules read: “You take the covers off, we cannot be responsible …”) So we took the covers off and we got a nice series of lessons on how to fix them, and we got better and better at it as we got more and more elaborate repairs. When we got something too complicated, we sent it back to the factory but we’d do the easy ones and kept the things going. I ended up doing all the computers and there was a guy in the machine shop who took care of typewriters.

Anyway we decided that the big problem—which was to figure out exactly what happened during the bomb’s implosion, so you can figure out exactly how much energy was released and so on—required much more calculating than we were capable of. A clever fellow by the name of Stanley Frankel realized that it could possibly he done on IBM machines. The IBM company had machines for business purposes, adding machines called tabulators for listing sums, and a multiplier that you put cards in and it would take two numbers from a card and multiply them. There were also collators and sorters and so on.

So Frankel figured out a nice program. If we got enough of these machines in a room, we could 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 then—mass production with machines. We had done things like this on adding machines. Usually you go one step across, doing everything yourself. But this was different—where you go first to the adder, then to the multiplier, then to the adder, and so on. So Frankel designed this system and ordered the machines from the IBM company because we realized it was a good way of solving our problems.

We needed a man to repair the machines, to keep them going and everything. And the army was always going to send this fellow they had, but he was always delayed. Now, we always were in a hurry. Everything we did, we tried to do as quickly as possible. In this particular case, we worked out all the numerical steps that the machines were supposed to do—multiply this, and then do this, and subtract that. Then we worked out the program, but we didn’t have any machine to test it on. So we set up this room with girls in it. Each one had a Marchant: one was the multiplier, another was the adder. This one cubed—all she did was cube a number on an index card and send it to the next girl.

We went through our cycle this way until we got all the bugs out. It turned out that the speed at which we were able to do it was a hell of a lot faster than the other way where every single person did all the steps. We got speed with this system that was the predicted speed for the IBM machine. The only difference is that the IBM machines didn’t get tired and could work three shifts. But the girls got tired after a while.

Anyway we got the bugs out during this process, and finally the machines arrived, but not the repairman. These were some of the most complicated machines of the technology of those days, big things that came partially disassembled, with lots of wires and blueprints of what to do. We went down and we put them together, Stan Frankel and I and another fellow, and we had our troubles. Most of the trouble was the big shots coming in all the time and saying, “You’re going to break something!”

We put them together, and sometimes they would work, and sometimes they were put together wrong and they didn’t work. Finally I was working on some multiplier and I saw a bent part inside, but I was afraid to straighten it because it might snap off—and they were always telling us we were going to bust something irreversibly. When the repairman finally got there, he fixed the machines we hadn’t got ready and everything was going. But he had trouble with the one that I had had trouble with. After three days he was still working on that one last machine.

I went down. I said, “Oh, I noticed that was bent.”

He said, “Oh, of course. That’s all there is to it!” Bend! It was all right. So that was it.

Well, Mr. Frankel, who started this program, began to suffer from the computer disease that anybody who works with computers now knows about. It’s a very serious disease and it interferes completely with the work. The trouble with computers is you play with them. They are so wonderful. You have these switches—if it’s an even number you do this, if it’s an odd number you do that—and pretty soon you can do more and more elaborate things if you are clever enough, on one machine.

After a while the whole system broke down. Frankel wasn’t paying any attention; he wasn’t supervising anybody. The system was going very, very slowly—while he was sitting in a room figuring out how to make one tabulator automatically print arc-tangent X, and then it would start and it would print columns and then bitsi, bitsi, bitsi, and calculate the arc-tangent automatically by integrating as it went along and make a whole table in one operation.

Absolutely useless. We had tables of arc-tangents. But if you’ve ever worked with computers, you understand the disease—the delight in being able to see how much you can do. But he got the disease for the first time, the poor fellow who invented the thing.

I was asked to stop working on the stuff I was doing in my group and go down and take over the IBM group, and I tried to avoid the disease. And, although they had done only three problems in nine months, I had a very good group.

The real trouble was that no one had ever told these fellows anything. The army had selected them from all over the country for a thing called Special Engineer Detachment—clever boys from high school who had engineering ability. They sent them up to Los Alamos. They put them in barracks. And they would tell them nothing.

Then they came to work, and what they had to do was work on IBM machines—punching holes, numbers that they didn’t understand. Nobody told them what it was. The thing was going very slowly. I said that the first thing there has to be is that these technical guys know what we’re doing. Oppenheimer went and talked to the security and got special permission so I could give a nice lecture about what we were doing, and they were all excited: “We’re fighting a war! We see what it is!” They knew what the numbers meant. If the pressure came out higher, that meant there was more energy released, and so on and so on. They knew what they were doing.

Complete transformation! They began to invent ways of doing it better. They improved the scheme. They worked at night. They didn’t need supervising in the night; they didn’t need anything. They understood everything; they invented several of the programs that we used.

So my boys really came through, and all that had to be done was to tell them what it was. As a result, although it took them nine months to do three problems before, we did nine problems in three months, which is nearly ten times as fast.

But one of the secret ways we did our problems was this. The problems consisted of a bunch of cards that had to go through a cycle. First add, then multiply—and so it went through the cycle of machines in this room, slowly, as it went around and around. So we figured a way to put a different colored set of cards through a cycle too, but out of phase. We’d do two or three problems at a time.

But this got us into another problem. Near the end of the war, for instance, just before we had to make a test in Albuquerque, the question was: How much energy would be released? We had been calculating the release from various designs, but we hadn’t computed for the specific design that was ultimately used. So Bob Christy came down and said, “We would like the results for how this thing is going to work in one month”—or some very short time, like three weeks.

I said, “It’s impossible.”

He said, “Look, you’re putting out nearly two problems a month. It takes only two weeks per problem, or three weeks per problem.”

I said, “I know. It really takes much longer to do the problem, but we’re doing them in parallel. As they go through, it takes a long time and there’s no way to make it go around faster.”

He went out, and I began to think. Is there a way to make it go around faster? What if we did nothing else on the machine, so nothing else was interfering? I put a challenge to the boys on the blackboard—CAN WE DO IT? They all start yelling, “Yes, we’ll work double shifts, we’ll work overtime,” all this kind of thing. “We’ll try it. We’ll try it!”

And so the rule was: All other problems out. Only one problem and just concentrate on this one. So they started to work.

My wife, Arlene, was ill with tuberculosis—very ill indeed. It looked as if something might happen at any minute, so I arranged ahead of time with a friend of mine in the dormitory to borrow his car in an emergency so I could get to Albuquerque quickly. His name was Klaus Fuchs. He was the spy, and he used his automobile to take the atomic secrets away from Los Alamos down to Santa Fe. But nobody knew that.

The emergency arrived. I borrowed Fuchs’s car and picked up a couple of hitchhikers, in case something happened with the car on the way to Albuquerque. Sure enough, just as we were driving into Santa Fe, we got a flat tire. The two guys helped me change the tire, and just as we were leaving Santa Fe, another tire went flat. We pushed the car into a nearby gas station.

The gas station guy was repairing somebody else’s car, and it was going to take a while before he could help us. I didn’t even think to say anything, but the two hitchhikers went over to the gas station man and told him the situation. Soon we had a new tire (but no spare—tires were hard to get during the war).

About thirty miles outside Albuquerque a third tire went flat, so I left the car on the road and we hitchhiked the rest of the way. I phoned a garage to go out and get the car while I went to the hospital to see my wife.

Arlene died a few hours after I got there. A nurse came in to fill out the death certificate, and went out again. I spent a little more time with my wife. Then I looked at the clock I had given her seven years before, when she had first become sick with tuberculosis. It was something which in those days was very nice: a digital clock whose numbers would change by turning around mechanically. The clock was very delicate and often stopped for one reason or another—I had to repair it from time to time—but I kept it going for all those years. Now, it had stopped once more—at 9:22, the time on the death certificate!

I remembered the time I was in my fraternity house at MIT when the idea came into my head completely out of the blue that my grandmother was dead. Right after that there was a telephone call, just like that. It was for Pete Bernays—my grandmother wasn’t dead. So I remembered that, in case somebody told me a story that ended the other way. I figured that such things can sometimes happen by luck—after all, my grandmother was very old—although people might think they happened by some sort of supernatural phenomenon.

Arlene had kept this clock by her bedside all the time she was sick, and now it stopped the moment she died. I can understand how a person who half believes in the possibility of such things, and who hasn’t got a doubting mind—especially in a circumstance like that—doesn’t immediately try to figure out what happened, but instead explains that no one touched the clock, and there was no possibility of explanation by normal phenomena. The clock simply stopped. It would become a dramatic example of these fantastic phenomena.

I saw that the light in the room was low, and then I remembered that the nurse had picked up the clock and turned it toward the light to see the face better. That could easily have stopped it.

I went for a walk outside. Maybe I was fooling myself, but I was surprised how I didn’t feel what I thought people would expect to feel under the circumstances. I wasn’t delighted, but I didn’t feel terribly upset, perhaps because I had known for seven years that something like this was going to happen.

I didn’t know how I was going to face all my friends up at Los Alamos. I didn’t want people with long faces talking to me about it. When I got back (yet another tire went flat on the way), they asked me what happened.

“She’s dead. And how’s the program going?”

They caught on right away that I didn’t want to moon over it.

(I had obviously done something to myself psychologically: Reality was so important—I had to understand what really happened to Arlene, physiologically—that I didn’t cry until a number of months later, when I was in Oak Ridge. I was walking past a department store with dresses in the window, and I thought Arlene would like one of them. That was too much for me.)

When I went back to work on the calculation program, I found it in a mess: There were white cards, there were blue cards, there were yellow cards, and I started to say, “You’re not supposed to do more than one problem—only one problem!” They said, “Get out, get out, get out. Wait—and we’ll explain everything.”

So I waited, and what happened was this. As the cards went through, sometimes the machine made a mistake, or they put a wrong number in. What we used to have to do when that happened was to go back and do it over again. But they noticed that a mistake made at some point in one cycle only affects the nearby numbers, the next cycle affects the nearby numbers, and so on. It works its way through the pack of cards. If you have fifty cards and you make a mistake at card number thirty-nine, it affects thirty-seven, thirty-eight, and thirty-nine. The next, card thirty-six, thirty-seven, thirty-eight, thirty-nine, and forty. The next time it spreads like a disease.

So they found an error back a way, and they got an idea. They would only compute a small deck of ten cards around the error. And because ten cards could he put through the machine faster than the deck of fifty cards, they would go rapidly through with this other deck while they continued with the fifty cards with the disease spreading. But the other thing was computing faster, and they would seal it all up and correct it. Very clever.

That was the way those guys worked to get speed. There was no other way. If they had to stop to try to fix it, we’d have lost time. We couldn’t have got it. That was what they were doing.

Of course, you know what happened while they were doing that. They found an error in the blue deck. And so they had a yellow deck with a little fewer cards; it was going around faster than the blue deck. Just when they are going crazy—because after they get this straightened out, they have to fix the white deck—the boss comes walking in.

“Leave us alone,” they say. I left them alone and everything came out. We solved the problem in time and that’s the way it was.

I was an underling at the beginning. Later I became a group leader. And I met some very great men. It is one of the great experiences of my life to have met all these wonderful physicists.

There was, of course, Enrico Fermi. He came down once from Chicago, to consult a little bit, to help us if we had some problems. We had a meeting with him, and I had been doing some calculations and gotten some results. The calculations were so elaborate it was very difficult. Now, usually I was the expert at this; I could always tell you what the answer was going to look like, or when I got it I could explain why. But this thing was so complicated I couldn’t explain why it was like that.

So I told Fermi I was doing this problem, and I started to describe the results. He said, “Wait, before you tell me the result, let me think. It’s going to come out like this (he was right), and it’s going to come out like this because of so and so. And there’s a perfectly obvious explanation for this—”

He was doing what I was supposed to be good at, ten times better. That was quite a lesson to me.

Then there was John von Neumann, the great mathematician. We used to go for walks on Sunday. We’d walk in the canyons, often with Bethe and Bob Bacher. It was a great pleasure. And von Neumann gave me an interesting idea: that you don’t have to be responsible for the world that you’re in. So I have developed a very powerful sense of social irresponsibility as a result of von Neumann’s advice. It’s made me a very happy man ever since. But it was von Neumann who put the seed in that grew into my active irresponsibility!

I also met Niels Bohr. His name was Nicholas Baker in those days, and he came to Los Alamos with Jim Baker, his son, whose name is really Aage Bohr. They came from Denmark, and they were very famous physicists, as you know. Even to the big shot guys, Bohr was a great god.

We were at a meeting once, the first time he came, and everybody wanted to see the great Bohr. So there were a lot of people there, and we were discussing the problems of the bomb. I was back in a corner somewhere. He came and went, and all I could see of him was from between people’s heads.

In the morning of the day he’s due to come next time, I get a telephone call.

“Hello—Feynman?”

“Yes.”

“This is Jim Baker.” It’s his son. “My father and I would like to speak to you.”

“Me? I’m Feynman, I’m just a—”

“That’s right. Is eight o’clock OK?”

So, at eight o’clock in the morning, before anybody’s awake, I go down to the place. We go into an office in the technical area and he says, “We have been thinking how we could make the bomb more efficient and we think of the following idea.”

I say, “No, it’s not going to work. It’s not efficient… Blab, blab, blah.”

So he says, “How about so and so?”

I said, “That sounds a little bit better, but it’s got this damn fool idea in it.”

This went on for about two hours, going back and forth over lots of ideas, back and forth, arguing. The great Niels kept lighting his pipe; it always went out. And he talked in a way that was un-understandable—mumble, mumble, hard to understand. His son I could understand better.

“Well,” he said finally, lighting his pipe, “I guess we can call in the big shots now.” So then they called all the other guys and had a discussion with them.

Then the son told me what happened. The last time he was there, Bohr said to his son, “Remember the name of that little fellow in the back over there? He’s the only guy who’s not afraid of me, and will say when I’ve got a crazy idea. So next time when we want to discuss ideas, we’re not going to be able to do it with these guys who say everything is yes, yes, Dr. Bohr. Get that guy and we’ll talk with him first.”

I was always dumb in that way. I never knew who I was talking to. I was always worried about the physics. If the idea looked lousy, I said it looked lousy. If it looked good, I said it looked good. Simple proposition.

I’ve always lived that way. It’s nice, it’s pleasant—if you can do it. I’m lucky in my life that I can do this.

After we’d made the calculations, the next thing that happened, of course, was the test. I was actually at home on a short vacation at that time, after my wife died, and so I got a message that said, “The baby is expected on such and such a day.”

I flew back, and I arrived just when the buses were leaving, so I went straight out to the site and we waited out there, twenty miles away. We had a radio, and they were supposed to tell us when the thing was going to go off and so forth, but the radio wouldn’t work, so we never knew what was happening. But just a few minutes before it was supposed to go off the radio started to work, and they told us there was twenty seconds or something to go, for people who were far away like we were. Others were closer, six miles away.

They gave out dark glasses that you could watch it with. Dark glasses! Twenty miles away, you couldn’t see a damn thing through dark glasses. So I figured the only thing that could really hurt your eyes (bright light can never hurt your eyes) is ultraviolet light. I got behind a truck windshield, because the ultraviolet can’t go through glass, so that would be safe, and so I could see the damn thing.

Time comes, and this tremendous flash out there is so bright that I duck, and I see this purple splotch on the floor of the truck. I said, “That’s not it. That’s an after-image.” So I look back up, and I see this white light changing into yellow and then into orange. Clouds form and disappear again—from the compression and expansion of the shock wave.

Finally, a big ball of orange, the center that was so bright, becomes a ball of orange that starts to rise and billow a little bit and get a little black around the edges, and then you see it’s a big ball of smoke with flashes on the inside, with the heat of the fire going outwards.

All this took about one minute. It was a series from bright to dark, and I had seen it. I am about the only guy who actually looked at the damn thing—the first Trinity test. Everybody else had dark glasses, and the people at six miles couldn’t see it because they were all told to lie on the floor. I’m probably the only guy who saw it with the human eye.

Finally, after about a minute and a half, there’s suddenly a tremendous noise—BANG, and then a rumble, like thunder—and that’s what convinced me. Nobody had said a word during this whole thing. We were all just watching quietly. But this sound released everybody—released me particularly because the solidity of the sound at that distance meant that it had really worked.

The man standing next to me said, “What’s that?”

I said, “That was the Bomb.”

The man was William Laurence. He was there to write an article describing the whole situation. I had been the one who was supposed to have taken him around. Then it was found that it was too technical for him, and so later H. D. Smyth came and I showed him around. One thing we did, we went into a room and there on the end of a narrow pedestal was a small silver-plated ball. You could put your hand on it. It was warm. It was radioactive. It was plutonium. And we stood at the door of this room, talking about it. This was a new element that was made by man, that had never existed on the earth before, except for a very short period possibly at the very beginning. And here it was all isolated and radioactive and had these properties. And we had made it. And so it was tremendously valuable.

Meanwhile, you know how people do when they talk—you kind of jiggle around and so forth. He was kicking the doorstop, you see, and I said, “Yes, the doorstop certainly is appropriate for this door.” The doorstop was a ten-inch hemisphere of yellowish metal—gold, as a matter of fact.

What had happened was that we needed to do an experiment to see how many neutrons were reflected by different materials, in order to save the neutrons so we didn’t use so much material. We had tested many different materials. We had tested platinum, we had tested zinc, we had tested brass, we had tested gold. So, in making the tests with the gold, we had these pieces of gold and somebody had the clever idea of using that great ball of gold for a doorstop for the door of the room that contained the plutonium.

After the thing went off, there was tremendous excitement at Los Alamos. Everybody had parties, we all ran around. I sat on the end of a jeep and beat drums and so on. But one man, I remember, Bob Wilson, was just sitting there moping.

I said, “What are you moping about?”

He said, “It’s a terrible thing that we made.”

I said, “But you started it. You got us into it.”

You see, what happened to me—what happened to the rest of us—is we started for a good reason, then you’re working very hard to accomplish something and it’s a pleasure, it’s excitement. And you stop thinking, you know; you just stop. Bob Wilson was the only one who was still thinking about it, at that moment.

I returned to civilization shortly after that and went to Cornell to teach, and my first impression was a very strange one. I can’t understand it any more, but I felt very strongly then. I sat in a restaurant in New York, for example, and I looked out at the buildings and I began to think, you know, about how much the radius of the Hiroshima bomb damage was and so forth … How far from here was 34th Street? … All those buildings, all smashed—and so on. And I would go along and I would see people building a bridge, or they’d be making a new road, and I thought, they’re crazy, they just don’t understand, they don’t understand. Why are they making new things? It’s so useless.

But, fortunately, it’s been useless for almost forty years now, hasn’t it? So I’ve been wrong about it being useless making bridges and I’m glad those other people had the sense to go ahead.

Safecracker Meets Safecracker

I learned to pick locks from a guy named Leo Lavatelli. It turns out that picking ordinary tumbler locks—like Yale locks—is easy. You try to turn the lock by putting a screwdriver in the hole (you have to push from the side in order to leave the hole open). It doesn’t turn because there are some pins inside which have to be lifted to just the right height (by the key). Because it is not made perfectly, the lock is held more by one pin than the others. Now, if you push a little wire gadget—maybe a paper clip with a slight bump at the end—and jiggle it back and forth inside the lock, you’ll eventually push that one pin that’s doing the most holding, up to the right height. The lock gives, just a little bit, so the first pin stays up—it’s caught on the edge. Now most of the load is held by another pin, and you repeat the same random process for a few more minutes, until all the pins are pushed up.

What often happens is that the screwdriver will slip and you hear tic-tic-tic, and it makes you mad. There are little springs that push the pins back down when a key is removed, and you can hear them click when you let go of the screwdriver. (Sometimes you intentionally let go of the screwdriver to see if you’re getting anywhere—you might be pushing the wrong way, for instance.) The process is something like Sisyphus: you’re always falling back downhill.

It’s a simple process, but practice helps a lot. You learn how hard to push on things—hard enough so the pins will stay up, but not so hard that they won’t go up in the first place. What is not really appreciated by most people is that they’re perpetually locking themselves in with locks everywhere, and it’s not very hard to pick them.

When we started to work on the atomic bomb project at Los Alamos, everything was in such a hurry that it wasn’t really ready. All the secrets of the project—everything about the atomic bomb—were kept in filing cabinets which, if they had locks at all, were locked with padlocks which had maybe only three pins: they were as easy as pie to open.

To improve security the shop ouffitted every filing cabinet with a long rod that went down through the handles of the drawers and that was fastened by a padlock.

Some guy said to me, “Look at this new thing the shop put on—can you open the cabinet now?”

I looked at the back of the cabinet and saw that the drawers didn’t have a solid bottom. There was a slot with a wire rod in each one that held a slidable piece (which holds the papers up inside the drawer). I poked in from the back, slid the piece back, and began pulling the papers out through the slot. “Look!” I said. “I don’t even have to pick the lock.”

Los Alamos was a very cooperative place, and we felt it our responsibility to point out things that should be improved. I’d keep complaining that the stuff was unsafe, and although everybody thought it was safe because there were steel rods and padlocks, it didn’t mean a damn thing.

To demonstrate that the locks meant nothing, whenever I wanted somebody’s report and they weren’t around, I’d just go in their office, open the filing cabinet, and take it out. When I was finished I would give it back to the guy: “Thanks for your report.”

“Where’d you get it?”

“Out of your filing cabinet.”

“But I locked it!”

“I know you locked it. The locks are no good.”

Finally some filing cabinets came which had combination locks on them made by the Mosler Safe Company. They had three drawers. Pulling the top drawer out would release the other drawers by a catch. The top drawer was opened by turning a combination wheel to the left, right, and left for the combination, and then right to number ten, which would draw back a bolt inside. The whole filing cabinet could be locked by closing the bottom drawers first, then the top drawer, and spinning the combination wheel away from number ten, which pushed up the bolt.

These new filing cabinets were an immediate challenge, naturally. I love puzzles. One guy tries to make something to keep another guy out; there must be a way to beat it!

I had first to understand how the lock worked, so I took apart the one in my office. The way it worked is this: There are three discs on a single shaft, one behind the other; each has a notch in a different place. The idea is to line up the notches so that when you turn the wheel to ten, the little friction drive will draw the bolt down into the slot generated by the notches of the three discs.

Now, to turn the discs, there’s a pin sticking out from the back of the combination wheel, and a pin sticking up from the first disc at the same radius. Within one turn of the combination wheel, you’ve picked up the first disc.

On the back of the first disc there’s a pin at the same radius as a pin on the front of the second disc, so by the time you’ve spun the combination wheel around twice, you’ve picked up the second disc as well.

Keep turning the wheel, and a pin on the back of the second disc will catch a pin on the front of the third disc, which you now set into the proper position with the first number of the combination.

Now you have to turn the combination wheel the other way one full turn to catch the second disc from the other side, and then continue to the second number of the combination to set the second disc.

Again you reverse direction and set the first disc to its proper place. Now the notches are lined up, and by turning the wheel to ten, you open the cabinet.

Well, I struggled, and I couldn’t get anywhere. I bought a couple of safecracker books, but they were all the same. In the beginning of the book there are some stories of the fantastic achievements of the safecracker, such as the woman caught in a meat refrigerator who is freezing to death, but the safecracker, hanging upside down, opens it in two minutes. Or there are some precious furs or gold bullion under water, down in the sea, and the safecracker dives down and opens the chest.

In the second part of the book, they tell you how to crack a safe. There are all kinds of ninny-pinny, dopey things, like “It might be a good idea to try a date for the combination, because lots of people like to use dates.” Or “Think of the psychology of the owner of the safe, and what he might use for the combination.” And “The secretary is often worried that she might forget the combination of the safe, so she might write it down in one of the following places—along the edge of her desk drawer, on a list of names and addresses … and so on.

They did tell me something sensible about how to open ordinary safes, and it’s easy to understand. Ordinary safes have an extra handle, so if you push down on the handle while you’re turning the combination wheel, things being unequal (as with locks), the force of the handle trying to push the bolt down into the notches (which are not lined up) is held up more by one disc than another. When the notch on that disc comes under the bolt, there’s a tiny click that you can hear with a stethoscope, or a slight decrease in friction that you can feel (you don’t have to sandpaper your fingertips), and you know, “There’s a number!”

You don’t know whether it’s the first, second, or third number, but you can get a pretty good idea of that by finding out how many times you have to turn the wheel the other way to hear the same click again. If it’s a little less than once, it’s the first disc; if it’s a little less than twice, it’s the second disc (you have to make a correction for the thickness of the pins).

This useful trick only works on ordinary safes, which have the extra handle, so I was stymied.

I tried all kinds of subsidiary tricks with the cabinets, such as finding out how to release the latches on the lower drawers, without opening the top drawer, by taking off a screw in front and poking around with a piece of hanger wire.

I tried spinning the combination wheel very rapidly and then going to ten, thus putting a little friction on, which I hoped would stop a disc at the right point in some manner. I tried all kinds of things. I was desperate.

I also did a certain amount of systematic study. For instance, a typical combination was 69-32-21. How far off could a number be when you’re opening the safe? If the number was 69, would 68 work? Would 67 work? On the particular locks we had, the answer was yes for both, but 66 wouldn’t work. You could he off by two in either direction. That meant you only had to try one out of five numbers, so you could try zero, five, ten, fifteen, and so on. With twenty such numbers on a wheel of 100, that was 8000 possibilities instead of the 1,000,000 you would get if you had to try every single number.

Now the question was, how long would it take me to try the 8000 combinations? Suppose I’ve got the first two numbers right of a combination I’m trying to get. Say the numbers are 69-32, but I don’t know it—I’ve got them as 70-30. Now I can try the twenty possible third numbers without having to set up the first two numbers each time. Now let’s suppose I have only the first number of the combination right. After trying the twenty numbers on the third disc, I move the second wheel only a little bit, and then do another twenty numbers on the third wheel.

I practiced all the time on my own safe so I could do this process as fast as I could and not get lost in my mind as to which number I was pushing and mess up the first number. Like a guy who practices sleight of hand, I got it down to an absolute rhythm so I could try the 400 possible back numbers in less than half an hour. That meant I could open a safe in a maximum of eight hours—with an average time of four hours.

There was another guy there at Los Alamos named Staley who was also interested in locks. We talked about it from time to time, but we weren’t getting anywhere much. After I got this idea how to open a safe in an average time of four hours, I wanted to show Staley how to do it, so I went into a guy’s office over in the computing department and asked, “Do you mind if I use your safe? I’d like to show Staley something.”

Meanwhile some guys in the computing department came around and one of them said, “Hey, everybody; Feynman’s gonna show Staley how to open a safe, ha, ha, ha!” I wasn’t going to actually open the safe; I was just going to show Staley this way of quickly trying the back two numbers without losing your place and having to set up the first number again.

I began. “Let’s suppose that the first number is forty, and we’re trying fifteen for the second number. We go back and forth, ten; back five more and forth, ten; and so on. Now we’ve tried all the possible third numbers. Now we try twenty for the second number: we go back and forth, ten; back five more and forth, ten; back five more and forth, CLICK!” My jaw dropped: the first and second numbers happened to be right!

Nobody saw my expression because my back was towards them. Staley looked very surprised, but both of us caught on Very quickly as to what happened, so I pulled the top drawer out with a flourish and said, “And there you are!”

Staley said, “I see what you mean; it’s a very good scheme”—and we walked out. Everybody was amazed. It was complete luck. Now I really had a reputation for opening safes.

It took me about a year and a half to get that far (of course, I was working on the bomb, too!) but I figured that I had the safes beaten, in the sense that if there was a real difficulty—if somebody was lost, or dead, and nobody else knew the combination but the stuff in the filing cabinet was needed—I could open it. After reading what preposterous things the safecrackers claimed, I thought that was a rather respectable accomplishment.

We had no entertainment there at Los Alamos, and we had to amuse ourselves somehow, so fiddling with the Mosler lock on my filing cabinet was one of my entertainments. One day I made an interesting observation: When the lock is opened and the drawer has been pulled out and the wheel is left on ten (which is what people do when they’ve opened their filing cabinet and are taking papers out of it), the bolt is still down. Now what does that mean, the bolt is still down? It means the bolt is in the slot made by the three discs, which are still properly lined up. Ahhhh!

Now, if I turn the wheel away from ten a little bit, the bolt comes up; if I immediately go back to ten, the bolt goes back down again, because I haven’t yet disturbed the slot. If I keep going away from ten in steps of five, at some point the bolt won’t go back down when I go back to ten: the slot has just been disturbed. The number just before, which still let the bolt go down, is the last number of the combination!

I realized that I could do the same thing to find the second number: As soon as I know the last number, I can turn the wheel around the other way and again, in lumps of five, push the second disc bit by bit until the bolt doesn’t go down. The number just before would be the second number.

If I were very patient I would be able to pick up all three numbers that way, but the amount of work involved in picking up the first number of the combination by this elaborate scheme would be much more than just trying the twenty possible first numbers with the other two numbers that you already know, when the filing cabinet is closed.

I practiced and I practiced until I could get the last two numbers off an open filing cabinet, hardly looking at the dial. Then, when I’d be in some guy’s office discussing some physics problem, I’d lean against his opened filing cabinet, and just like a guy who’s jiggling keys absent-mindedly while he’s talking, I’d just wobble the dial back and forth, back and forth. Sometimes I’d put my finger on the bolt so I wouldn’t have to look to see if it’s coming up. In this way I picked off the last two numbers of various filing cabinets. When I got back to my office I would write the two numbers down on a piece of paper that I kept inside the lock of my filing cabinet. I took the lock apart each time to get the paper—I thought that was a very safe place for them.

After a while my reputation began to sail, because things like this would happen: Somebody would say, “Hey, Feynman! Christy’s out of town and we need a document from his safe—can you open it?”

If it was a safe I knew I didn’t have the last two numbers of, I would simply say, “I’m sorry, but I can’t do it now; I’ve got this work that I have to do.” Otherwise, I would say, “Yeah, but I gotta get my tools.” I didn’t need any tools, but I’d go back to my office, open my filing cabinet, and look at my little piece of paper: “Christy—35, 60.” Then I’d get a screwdriver and go over to Christy’s office and close the door behind me. Obviously not everybody is supposed to be allowed to know how to do this!

I’d be in there alone and I’d open the safe in a few minutes. All I had to do was try the first number at most twenty times, then sit around, reading a magazine or something, for fifteen or twenty minutes. There was no use trying to make it look too easy; somebody would figure out there was a trick to it! After a while I’d open the door and say, “It’s open.”

People thought I was opening the safes from scratch. Now I could maintain the idea, which began with that accident with Staley, that I could open safes cold. Nobody figured out that I was picking the last two numbers off their safes, even though—perhaps because—I was doing it all the time, like a card sharp walking around all the time with a deck of cards,

I often went to Oak Ridge to check up on the safety of the uranium plant. Everything was always in a hurry because it was wartime, and one time I had to go there on a weekend. It was Sunday, and we were in this fella’s office—a general, a head or a vice president of some company, a couple of other big muck-a-mucks, and me. We were gathered together to discuss a report that was in the fella’s safe—a secret safe—when suddenly he realized that he didn’t know the combination. His secretary was the only one who knew it, so he called her home and it turned out she had gone on a picnic up in the hills.

While all this was going on, I asked, “Do you mind if I fiddle with the safe?”

“Ha, ha, ha—not at all!” So I went over to the safe and started to fool around.

They began to discuss how they could get a car to try to find the secretary, and the guy was getting more and more embarrassed because he had all these people waiting and he was such a jackass he didn’t know how to open his own safe. Everybody was all tense and getting mad at him, when CLICK!—the safe opened.

In 10 minutes I had opened the safe that contained all the secret documents about the plant. They were astonished. The safes were apparently not very safe. It was a terrible shock: All this “eyes only” stuff, top secret, locked in this wonderful secret safe, and this guy opens it in ten minutes!

Of course I was able to open the safe because of my perpetual habit of taking the last two numbers off. While in Oak Ridge the month before, I was in the same office when the safe was open and I took the numbers off in an absentminded way—I was always practicing my obsession. Although I hadn’t written them down, I was able to vaguely remember what they were. First I tried 40-15, then 15-40, but neither of those worked. Then I tried 10-45 with all the first numbers, and it opened.

A similar thing happened on another weekend when I was visiting Oak Ridge. I had written a report that had to be OKed by a colonel, and it was in his safe. Everybody else keeps documents in filing cabinets like the ones at Los Alamos, but he was a colonel, so he had a much fancier, two-door safe with big handles that pull four ¾-inch-thick steel bolts from the frame. The great brass doors swung open and he took out my report to read.

Not having had an opportunity to see any really good safes, I said to him, “Would you mind, while you’re reading my report, if I looked at your safe?”

“Go right ahead,” he said, convinced that there was nothing I could do. I looked at the back of one of the solid brass doors, and I discovered that the combination wheel was connected to a little lock that looked exactly the same as the little unit that was on my filing cabinet at Los Alamos. Same company, same little bolt, except that when the bolt came down, the big handles on the safe could then move some rods sideways, and with a hunch of levers you could pull back all those ¾-inch steel rods. The whole lever system, it appeared, depends on the same little bolt that locks filing cabinets.

Just for the sake of professional perfection, to make sure it was the same, I took the two numbers off the same way I did with the filing cabinet safes.

Meanwhile, he was reading the report. When he’d finished he said, “All right, it’s fine.” He put the report in the safe, grabbed the big handles, and swung the great brass doors together. It sounds so good when they close, but I know it’s all psychological, because it’s nothing but the same damn lock.

I couldn’t help but needle him a little bit (I always had a thing about military guys, in such wonderful uniforms) so I said, “The way you close that safe, I get the idea that you think things are safe in there.”

“Of course.”

“The only reason you think they’re safe in there is because civilians call it a ‘safe.’” (I put the word “civilians” in there to make it sound as if he’d been had by civilians.)

He got very angry. “What do you mean—it’s not safe?”

“A good safecracker could open it in thirty minutes.”

“Can you open it in thirty minutes?”

“I said a good safecracker. It would take me about forty-five.”

“Well!” he said. “My wife is waiting at home for me with supper, but I’m gonna stay here and watch you, and you’re gonna sit down there and work on that damn thing for forty-five minutes and not open it!” He sat down in his big leather chair, put his feet up on his desk, and read.

With complete confidence I picked up a chair, carried it over to the safe and sat down in front of it. I began to turn the wheel at random, just to make some action.

After about five minutes, which is quite a long time when you’re just sitting and waiting, he lost some patience: “Well, are you making any progress?”

“With a thing like this, you either open it or you don’t.”

I figured one or two more minutes would be about time, so I began to work in earnest and two minutes later, CLINK—it opened.

The colonel’s jaw dropped and his eyes bugged out.

“Colonel,” I said, in a serious tone, “let me tell you something about these locks: When the door to the safe or the top drawer of the filing cabinet is left open, it’s very easy for someone to get the combination. That’s what I did while you were reading my report, just to demonstrate the danger. You should insist that everybody keep their filing cabinet drawers locked while they’re working, because when they’re open, they’re very, very vulnerable.”

“Yeah! I see what you mean! That’s very interesting!” We were on the same side after that.

The next time I went to Oak Ridge, all the secretaries and people who knew who I was were telling me, “Don’t come through here! Don’t come through here!”

The colonel had sent a note around to everyone in the plant which said, “During his last visit, was Mr. Feynman at any time in your office, near your office, or walking through your office?” Some people answered yes; others said no. The ones who said yes got another note: “Please change the combination of your safe.”

That was his solution: I was the danger. So they all had to change their combinations on account of me. It’s a pain in the neck to change a combination and remember the new one, so they were all mad at me and didn’t want me to come near them: they might have to change their combination once again. Of course, their filing cabinets were still left open while they were working!

A library at Los Alamos held all of the documents we had ever worked on: It was a solid, concrete room with a big, beautiful door which had a metal wheel that turns—like a safe-deposit vault. During the war I had tried to look at it closely. I knew the girl who was the librarian, and I begged her to let me play with it a little bit. I was fascinated by it: it was the biggest lock I ever saw! I discovered that I could never use my method of picking off the last two numbers to get in. In fact, while turning the knob while the door was open, I made the lock close, so it was sticking out, and they couldn’t close the door again until the girl came and opened the lock again. That was the end of my fiddling around with that lock. I didn’t have time to figure out how it worked; it was much beyond my capacity.

During the summer after the war I had some documents to write and work to finish up, so I went back to Los Alamos from Cornell, where I had taught during the year. In the middle of my work I had to refer to a document that I had written before but couldn’t remember, and it was down in the library.

I went down to get the document, and there was a soldier walking back and forth, with a gun. It was a Saturday, and after the war the library was closed on Saturdays.

Then I remembered what a good friend of mine, Frederic de Hoffman, had done. He was in the Declassification Section. After the war the army was thinking of declassifying some documents, and he had to go back and forth to the library so much—look at this document, look at that document, check this, check that—that he was going nuts! So he had a copy of every document—all the secrets to the atomic bomb—in nine filing cabinets in his office.

I went down to his office, and the lights were on. It looked as if whoever was there—perhaps his secretary—had just stepped out for a few minutes, so I waited. While I was waiting I started to fiddle around with the combination wheel on one of the filing cabinets. (By the way, I didn’t have the last two numbers for de Hoffman’s safes; they were put in after the war, after I had left.)

I started to play with one of the combination wheels and began to think about the safecracker books. I thought to myself, “I’ve never been much impressed by the tricks described in those books, so I’ve never tried them, but let’s see if we can open de Hoffman’s safe by following the book.”

First trick, the secretary: she’s afraid she’s going to forget the combination, so she writes it down somewhere. I started to look in some of the places mentioned in the book. The desk drawer was locked, but it was an ordinary lock like Leo Lavatelli taught me how to open—ping! I look along the edge: nothing.

Then I looked through the secretary’s papers. I found a sheet of paper that all the secretaries had, with the Greek letters carefully made—so they could recognize them in mathematical formulas—and named. And there, carelessly written along the top of the paper, was pi = 3.14159. Now, that’s six digits, and why does a secretary have to know the numerical value of pi? It was obvious; there was no other reason!

I went over to the filing cabinets and tried the first one: 31-41-59. It didn’t open. Then I tried 59-41-31. That didn’t work either. Then 95-14-13. Backwards, forwards, upside down, turn it this way, turn it that—nothing!

I closed the desk drawer and started to walk out the door, when I thought of the safecracker books again: Next, try the psychology method. I said to myself, “Freddy de Hoffman is just the kind of guy to use a mathematical constant for a safe combination.”

I went back to the first filing cabinet and tried 27-18-28—CLICK! It opened! (The mathematical constant second in importance to pi is the base of natural logarithms, e: 2.71828 …) There were nine filing cabinets, and I had opened the first one, but the document I wanted was in another one—they were in alphabetical order by author. I tried the second filing cabinet: 27-18-28–CLICK! It opened with the same combination. I thought, “This is wonderful! I’ve opened the secrets to the atomic bomb, but if I’m ever going to tell this story, I’ve got to make sure that all the combinations are really the same!” Some of the filing cabinets were in the next room, so I tried 27-18-28 on one of them, and it opened. Now I’d opened three safes—all the same.

I thought to myself, “Now I could write a safecracker book that would beat every one, because at the beginning I would tell how I opened safes whose contents were bigger and more valuable than what any safecracker anywhere had opened—except for a life, of course—but compared to the furs or the gold bullion, I have them all beat: I opened the safes which contained all the secrets to the atomic bomb: the schedules for the production of the plutonium, the purification procedures, how much material is needed, how the bomb works, how the neutrons are generated, what the design is, the dimensions—the entire information that was known at Los Alamos: the whole shmeer! ”

I went back to the second filing cabinet and took out the document I wanted. Then I took a red grease pencil and a piece of yellow paper that was lying around in the office and wrote, “I borrowed document no. LA4312—Feynman the safecracker.” I put the note on top of the papers in the filing cabinet and closed it.

Then I went to the first one I had opened and wrote another note: “This one was no harder to open than the other one—Wise Guy” and shut the cabinet.

Then in the other cabinet, in the other room, I wrote, “When the combinations are all the same, one is no harder to open than another—Same Guy” and I shut that one. I went back to my office and wrote my report.

That evening I went to the cafeteria and ate supper. There was Freddy de Hoffman. He said he was going over to his office to work, so just for fun I went with him.

He started to work, and soon he went into the other room to open one of the filing cabinets in there—something I hadn’t counted on—and he happened to open the filing cabinet I had put the third note in, first. He opened the drawer, and he saw this foreign object in there—this bright yellow paper with something scrawled on it in bright red crayon.

I had read in books that when somebody is afraid, his face gets sallow, but I had never seen it before. Well, it’s absolutely true. His face turned a gray, yellow green—it was really frightening to see. He picked up the paper, and his hand was shaking. “L-l-look at this!” he said, trembling.

The note said, “When the combinations are all the same, one is no harder to open than another—Same Guy.”

“What does it mean?” I said.

“All the c-c-combinations of my safes are the s-s-same!” he stammered.

“That ain’t such a good idea.”

“I-I know that n-now!” he said, completely shaken.

Another effect of the blood draining from the face must be that the brain doesn’t work right. “He signed who it was! He signed who it was!” he said.

“What?” (I hadn’t put my name on that one.)

“Yes,” he said, “it’s the same guy who’s been trying to get into Building Omega!”

All during the war, and even after, there were these perpetual rumors: “Somebody’s been trying to get into Building Omega!” You see, during the war they were doing experiments for the bomb in which they wanted to get enough material together for the chain reaction to just get started. They would drop one piece of material through another, and when it went through, the reaction would start and they’d measure how many neutrons they got. The piece would fall through so fast that nothing should build up and explode. Enough of a reaction would begin, however, so they could tell that things were really starting correctly, that the rates were right, and everything was going according to prediction—a very dangerous experiment!

Naturally, they were not doing this experiment in the middle of Los Alamos, but off several miles, in a canyon several mesas over, all isolated. This Building Omega had its own fence around it with guard towers. In the middle of the night when everything’s quiet, some rabbit comes out of the brush and smashes against the fence and makes a noise. The guard shoots. The lieutenant in charge comes around. What’s the guard going to say—that it was only a rabbit? No. “Somebody’s been trying to get into Building Omega and I scared him off!”

So de Hoffman was pale and shaking, and he didn’t realize there was a flaw in his logic: it was not clear that the same guy who’d been trying to get into Building Omega was the same guy who was standing next to him.

He asked me what to do.

“Well, see if any documents are missing.”

“It looks all right,” he said. “I don’t see any missing.”

I tried to steer him to the filing cabinet I took my document out of. “Well, uh, if all the combinations are the same, perhaps he’s taken something from another drawer.”

“Right!” he said, and he went back into his office and opened the first filing cabinet and found the second note I wrote: “This one was no harder than the other one—Wise Guy.”

By that time it didn’t make any difference whether it was “Same Guy” or “Wise Guy”: It was completely clear to him that it was the guy who was trying to get into Building Omega. So to convince him to open the filing cabinet with my first note in it was particularly difficult, and I don’t remember how I talked him into it.

He started to open it, so I began to walk down the hall, because I was a little bit afraid that when he found out who did it to him, I was going to get my throat cut!

Sure enough, he came running down the hall after me, but instead of being angry, he practically put his arms around me because he was so completely relieved that this terrible burden of the atomic secrets being stolen was only me doing mischief.

A few days later de Hoffman told me that he needed something from Kerst’s safe. Donald Kerst had gone back to Illinois and was hard to reach. “If you can open all my safes using the psychological method,” de Hoffman said (I had told him how I did it), “maybe you could open Kerst’s safe that way.”

By now the story had gotten around, so several people came to watch this fantastic process where I was going to open Kerst’s safe—cold. There was no need for me to be alone. I didn’t have the last two numbers to Kerst’s safe, and to use the psychology method I needed people around who knew Kerst.

We all went over to Kerst’s office and I checked the drawers for clues; there was nothing. Then I asked them, “What kind of a combination would Kerst use—a mathematical constant?”

“Oh, no!” de Hoffman said. “Kerst would do something very simple.”

I tried 10-20-30, 20-40-60, 60-40-20, 30-20-10. Nothing.

Then I said, “Do you think he would use a date?”

“Yeah!” they said. “He’s just the kind of guy to use a date.”

We tried various dates: 8-6-45, when the bomb went off; 86-19-45; this date; that date; when the project started. Nothing worked.

By this time most of the people had drifted off. They didn’t have the patience to watch me do this, but the only way to solve such a thing is patience!

Then I decided to try everything from around 1900 until now. That sounds like a lot, but it’s not: the first number is a month, one through twelve, and I can try that using only three numbers: ten, five, and zero. The second number is a day, from one to thirty-one, which I can try with six numbers. The third number is the year, which was only forty-seven numbers at that time, which I could try with nine numbers. So the 8000 combinations had been reduced to 162, something I could try in fifteen or twenty minutes.

Unfortunately I started with the high end of the numbers for the months, because when I finally opened it, the combination was 0-5-35.

I turned to de Hoffman. “What happened to Kerst around January 5, 1935?”

“His daughter was born in 1936,” de Hoffman said. “It must be her birthday.”

Now I had opened two safes cold. I was getting good. Now I was professional.

That same summer after the war, the guy from the property section was trying to take back some of the things the government had bought, to sell again as surplus. One of the things was a Captain’s safe. We all knew about this safe. The Captain, when he arrived during the war, decided that the filing cabinets weren’t safe enough for the secrets he was going to get, so he had to have a special safe.

The Captain’s office was on the second floor of one of the flimsy wooden buildings that we all had our offices in, and the safe he ordered was a heavy steel safe. The workmen had to put down platforms of wood and use special jacks to get it up the steps. Since there wasn’t much amusement, we all watched this big safe being moved up to his office with great effort, and we all made jokes about what kind of secrets he was going to keep in there. Some fella said we oughta put our stuff in his safe, and let him put his stuff in ours. So everyone knew about this safe.

The property section man wanted it for surplus, but first it had to be emptied, and the only people who knew the combination were the Captain, who was in Bikini, and Alvarez, who’d forgotten it. The man asked me to open it.

I went up to his old office and said to the secretary, “Why don’t you phone the Captain and ask him the combination?”

“I don’t want to bother him,” she said.

“Well, you’re gonna bother me for maybe eight hours. I won’t do it unless you make an attempt to call him.”

“OK, OK!” she said. She picked up the telephone and I went into the other room to look at the safe. There it was, that huge, steel safe, and its doors were wide open.

I went back to the secretary. “It’s open.”

“Marvelous!” she said, as she put down the phone.

“No,” I said, “it was already open.”

“Oh! I guess the property section was able to open it after all.”

I went down to the man in the property section. “I went up to the safe and it was already open.”

“Oh, yeah,” he said; “I’m sorry I didn’t tell you. I sent our regular locksmith up there to drill it, but before he drilled it he tried to open it, and he opened it.”

So! First information: Los Alamos now has a regular locksmith. Second information: This man knows how to drill safes, something I know nothing about. Third information: He can open a safe cold—in a few minutes. This is a real professional, a real source of information. This guy I have to meet.

I found out he was a locksmith they had hired after the war (when they weren’t as concerned about security) to take care of such things. It turned out that he didn’t have enough work to do opening safes, so he also repaired the Marchant calculators we had used. During the war I repaired those things all the time—so I had a way to meet him.

Now I have never been surreptitious or tricky about meeting somebody; I just go right up and introduce myself. But in this case it was so important to meet this man, and I knew that before he would tell me any of his secrets on how to open safes, I would have to prove myself.

I found out where his room was—in the basement of the theoretical physics section, where I worked—and I knew he worked in the evening, when the machines weren’t being used. So, at first I would walk past his door on my way to my office in the evening. That’s all; I’d just walk past.

A few nights later, just a “Hi.” After a while, when he saw it was the same guy walking past, he’d say “Hi,” or “Good evening.”

A few weeks of this slow process and I see he’s working on the Marchant calculators. I say nothing about them; it isn’t time yet.

We gradually say a little more: “Hi! I see you’re working pretty hard!”

“Yeah, pretty hard”—that kind of stuff.

Finally, a breakthrough: he invites me for soup. It’s going very good now. Every evening we have soup together. Now I begin to talk a little bit about the adding machines, and he tells me he has a problem. He’s been trying to put a succession of spring-loaded wheels back onto a shaft, and he doesn’t have the right tool, or something; he’s been working on it for a week. I tell him that I used to work on those machines during the war, and “I’ll tell you what: you just leave the machine out tonight, and I’ll have a look at it tomorrow.”

“OK,” he says, because he’s desperate.

The next day I looked at the damn thing and tried to load it by holding all the wheels in my hand. It kept snapping back. I thought to myself, “If he’s been trying the same thing for a week, and I’m trying it and can’t do it, it ain’t the way to do it!” I stopped and looked at it very carefully, and I noticed that each wheel had a little hole—just a little hole. Then it dawned on me: I sprung the first one; then I put a piece of wire through the little hole. Then I sprung the second one and put the wire through it. Then the next one, the next one—like putting beads on a string—and I strung the whole thing the first time I tried it, got it all in line, pulled the wire out, and everything was OK.

That night I showed him the little hole and how I did it, and from then on we talked a lot about machines; we got to be good friends. Now, in his office there were a lot of little cubbyholes that contained locks half taken apart, and pieces from safes, too. Oh, they were beautiful! But I still didn’t say a word about locks and safes.

Finally, I figured the day was coming, so I decided to put out a little bit of bait about safes: I’d tell him the only thing worth a damn that I knew about them—that you can take the last two numbers off while it’s open. “Hey!” I said, looking over at the cubbyholes. “I see you’re working on Mosler safes.”

“Yeah.”

“You know, these locks are weak. If they’re open, you can take the last two numbers off …”

“You can?” he said, finally showing some interest.

“Yeah.”

“Show me how,” he said. I showed him how to do it, and he turned to me. “What’s your name?” All this time we had never exchanged names.

“Dick Feynman,” I said.

“God! You’re Feynman!” he said in awe. “The great safecracker! I’ve heard about you; I’ve wanted to meet you for so long! I want to learn how to crack a safe from you.”

“What do you mean? You know how to open safes cold.”

“I don’t.”

“Listen, I heard about the Captain’s safe, and I’ve been working pretty hard all this time because I wanted to meet you. And you tell me you don’t know how to open a safe cold.”

“That’s right.”

“Well you must know how to drill a safe.”

“I don’t know how to do that either.”

“WHAT?” I exclaimed. “The guy in the property section said you picked up your tools and went up to drill the Captain’s safe.”

“Suppose you had a job as a locksmith,” he said, “and a guy comes down and asks you to drill a safe. What would you do?”

“Well,” I replied, “I’d make a fancy thing of putting my tools together, pick them up and take them to the safe. Then I’d put my drill up against the safe somewhere at random and I’d go vvvvvvvvvvv, so I’d save my job.”

“That’s exactly what I was going to do.”

“But you opened it! You must know how to crack safes.”

“Oh, yeah. I knew that the locks come from the factory set at 25-0-25 or 50-25-50, so I thought, ‘Who knows; maybe the guy didn’t bother to change the combination,’ and the second one worked.”

So I did learn something from him—that he cracked safes by the same miraculous methods that I did. But even funnier was that this big shot Captain had to have a super, super safe, and had people go to all that trouble to hoist the thing up into his office, and he didn’t even bother to set the combination.

I went from office to office in my building, trying those two factory combinations, and I opened about one safe in five.

Uncle Sam Doesn’t Need You!

After the war the army was scraping the bottom of the barrel to get the guys for the occupation forces in Germany. Up until then the army deferred people for some reason other than physical first (I was deferred because I was working on the bomb), but now they reversed that and gave everybody a physical first.

That summer I was working for Hans Bethe at General Electric in Schenectady, New York, and I remember that I had to go some distance—I think it was to Albany—to take the physical.

I get to the draft place, and I’m handed a lot of forms to fill out, and then I start going around to all these different booths. They check your vision at one, your hearing at another, they take your blood sample at another, and so forth.

Anyway, finally you come to booth number thirteen: psychiatrist. There you wait, sitting on one of the benches, and while I’m waiting I can see what is happening. There are three desks, with a psychiatrist behind each one, and the “culprit” sits across from the psychiatrist in his BVDs and answers various questions.

At that time there were a lot of movies about psychiatrists. For example, there was Spellbound, in which a woman who used to be a great piano player has her hands stuck in some awkward position and she can’t move them, and her family calls in a psychiatrist to try to help her, and the psychiatrist goes upstairs into a room with her, and you see the door close behind them, and downstairs the family is discussing what’s going to happen, and then she comes out of the room, hands still stuck in the horrible position, walks dramatically down the stairs over to the piano and sits down, lifts her hands over the keyboard, and suddenly—dum diddle dum diddle dum, dum, dum–she can play again. Well, I can’t stand this kind of baloney, and I had decided that psychiatrists are fakers, and I’ll have nothing to do with them. So that was the mood I was in when it was my turn to talk to the psychiatrist.

I sit down at the desk, and the psychiatrist starts looking through my papers. “Hello, Dick!” he says in a cheerful voice. “Where do you work?”

I’m thinking, “Who does he think he is, calling me by my first name?” and I say coldly, “Schenectady.”

“Who do you work for, Dick?” says the psychiatrist, smiling again.

“General Electric.”

“Do you like your work, Dick?” he says, with that same big smile on his face.

“So-so.” I just wasn’t going to have anything to do with him.

Three nice questions, and then the fourth one is completely different. “Do you think people talk about you?” he asks, in a low, serious tone.

I light up and say, “Sure! When I go home, my mother often tells me how she was telling her friends about me.” He isn’t listening to the explanation; instead, he’s writing something down on my paper.

Then again, in a low, serious tone, he says, “Do you think people stare at you?”

I’m all ready to say no, when he says, “For instance, do you think any of the boys waiting on the benches are staring at you now?”

While I had been waiting to talk to the psychiatrist, I had noticed there were about twelve guys on the benches waiting for the three psychiatrists, and they’ve got nothing else to look at, so I divide twelve by three—that makes four each—but I’m conservative, so I say, “Yeah, maybe two of them are looking at us.”

He says, “Well just turn around and look”—and he’s not even bothering to look himself!

So I turn around, and sure enough, two guys are looking. So I point to them and I say, “Yeah—there’s that guy, and that guy over there looking at us.” Of course, when I’m turned around and pointing like that, other guys start to look at us, so I say, “Now him, and those two over there—and now the whole bunch.” He still doesn’t look up to check. He’s busy writing more things on my paper.

Then he says, “Do you ever hear voices in your head?”

“Very rarely,” and I’m about to describe the two occasions on which it happened when he says, “Do you talk to yourself?”

“Yeah, sometimes when I’m shaving, or thinking; once in a while.” He’s writing down more stuff.

“I see you have a deceased wife—do you talk to her?”

This question really annoyed me, but I contained myself and said, “Sometimes, when I go up on a mountain and I’m thinking about her.”

More writing. Then he asks, “Is anyone in your family in a mental institution?”

“Yeah, I have an aunt in an insane asylum.”

“Why do you call it an insane asylum?” he says, resentfully. “Why don’t you call it a mental institution?”

“I thought it was the same thing.”

“Just what do you think insanity is?” he says, angrily.

“It’s a strange and peculiar disease in human beings,” I say honestly.

“There’s nothing any more strange or peculiar about it than appendicitis!” he retorts.

“I don’t think so. In appendicitis we understand the causes better, and something about the mechanism of it, whereas with insanity it’s much more complicated and mysterious.” I won’t go through the whole debate; the point is that I meant insanity is physiologically peculiar, and he thought I meant it was socially peculiar.

Up until this time, although I had been unfriendly to the psychiatrist, I had nevertheless been honest in everything I said. But when he asked me to put out my hands, I couldn’t resist pulling a trick a guy in the “bloodsucking line” had told me about. I figured nobody was ever going to get a chance to do this, and as long as I was halfway under water, I would do it. So I put out my hands with one palm up and the other one down.

The psychiatrist doesn’t notice. He says, “Turn them over.”

I turn them over. The one that was up goes down, and the one that was down goes up, and he still doesn’t notice, because he’s always looking very closely at one hand to see if it is shaking. So the trick had no effect.

Finally, at the end of all these questions, he becomes friendly again. He lights up and says, “I see you have a Ph.D., Dick. Where did you study?”

“MIT and Princeton. And where did you study!”

“Yale and London. And what did you study, Dick?”

“Physics. And what did you study?”

“Medicine.”

“And this is medicine?”

“Well, yes. What do you think it is? You go and sit down over there and wait a few minutes!”

So I sit on the bench again, and one of the other guys waiting sidles up to me and says, “Gee! You were in there twenty-five minutes! The other guys were in there only five minutes!”

“Yeah.”

“Hey,” he says. “You wanna know how to fool the psychiatrist? All you have to do is pick your nails, like this.”

“Then why don’t you pick your nails like that?”

“Oh,” he says, “I wanna get in the army!”

“You wanna fool the psychiatrist?” I say. “You just tell him that!”

After a while I was called over to a different desk to see another psychiatrist. While the first psychiatrist had been rather young and innocent-looking, this one was gray-haired and distinguished-looking—obviously the superior psychiatrist. I figure all of this is now going to get straightened out, but no matter what happens, I’m not going to become friendly.

The new psychiatrist looks at my papers, puts a big smile on his face, and says, “Hello, Dick. I see you worked at Los Alamos during the war.”

“Yeah.”

“There used to be a boys’ school there, didn’t there?”

“That’s right.”

“Were there a lot of buildings in the school?”

“Only a few.”

Three questions—same technique—and the next question is completely different. “You said you hear voices in your head. Describe that, please.”

“It happens very rarely, when I’ve been paying attention to a person with a foreign accent. As I’m falling asleep I can hear his voice very clearly. The first time it happened was while I was a student at MIT. I could hear old Professor Vallarta say, ‘Dee-a dee-a electric field-a.’ And the other time was in Chicago during the war, when Professor Teller was explaining to me how the bomb worked. Since I’m interested in all kinds of phenomena, I wondered how I could hear these voices with accents so precisely, when I couldn’t imitate them that well … Doesn’t everybody have something like that happen once in a while?”

The psychiatrist put his hand over his face, and I could see through his fingers a little smile (he wouldn’t answer the question).

Then the psychiatrist checked into something else. “You said that you talk to your deceased wife. What do you say to her?”

I got angry. I figure it’s none of his damn business, and I say, “I tell her I love her, if it’s all right with you!”

After some more bitter exchanges he says, “Do you believe in the supernormal?”

I say, “I don’t know what the ‘supernormal’ is.”

“What? You, a Ph.D. in physics, don’t know what the supernormal is?”

“That’s right.”

“It’s what Sir Oliver Lodge and his school believe in.”

That’s not much of a clue, but I knew it. “You mean the supernatural.”

“You can call it that if you want.”

“All right, I will.”

“Do you believe in mental telepathy?”

“No. Do you?”

“Well, I’m keeping an open mind.”

“What? You, a psychiatrist, keeping an open mind? Ha!” It went on like this for quite a while.

Then at some point near the end he says, “How much do you value life?”

“Sixty-four.”

“Why did you say ‘sixty-four’?”

“How are you supposed to measure the value of life?”

“No! I mean, why did you say ‘sixty-four,’ and not ‘seventy-three,’ for instance?”

“If I had said ‘seventy-three,’ you would have asked me the same question!”

The psychiatrist finished with three friendly questions, just as the other psychiatrist had done, handed me my papers, and I went off to the next booth.

While I’m waiting in the line, I look at the paper which has the summary of all the tests I’ve taken so far. And just for the hell of it I show my paper to the guy next to me, and I ask him in a rather stupid-sounding voice, “Hey! What did you get in ‘Psychiatric’? Oh! You got an ‘N.’ I got an ‘N’ in everything else, but I got a ‘D’ in ‘Psychiatric.’ What does that mean?” I knew what it meant: “N” is normal, “D” is deficient.

The guy pats me on the shoulder and says, “Buddy, it’s perfectly all right. It doesn’t mean anything. Don’t worry about it!” Then he walks way over to the other corner of the room, frightened: It’s a lunatic!

I started looking at the papers the psychiatrists had written, and it looked pretty serious! The first guy wrote:

Thinks people talk about him.

Thinks people stare at him.

Auditory hypnogogic hallucinations.

Talks to self.

Talks to deceased wife.

Maternal aunt in mental institution.

Very peculiar stare. (I knew what that was—that was when I said, “And this is medicine?”)

The second psychiatrist was obviously more important, because his scribble was harder to read. His notes said things like “auditory hypnogogic hallucinations confirmed.” (“Hypnogogic” means you get them while you’re falling asleep.)

He wrote a lot of other technical-sounding notes, and I looked them over, and they looked pretty bad. I figured I’d have to get all of this straightened out with the army somehow.

At the end of the whole physical examination there’s an army officer who decides whether you’re in or you’re out. For instance, if there’s something the matter with your hearing, he has to decide if it’s serious enough to keep you out of the army. And because the army was scraping the bottom of the barrel for new recruits, this officer wasn’t going to take anything from anybody. He was tough as nails. For instance, the fellow ahead of me had two bones sticking out from the back of his neck—some kind of displaced vertebra, or something—and this army officer had to get up from his desk and feel them—he had to make sure they were real!

I figure this is the place I’ll get this whole misunderstanding straightened out. When it’s my turn, I hand my papers to the officer, and I’m ready to explain everything, but the officer doesn’t look up. He sees the “D” next to “Psychiatric,” immediately reaches for the rejection stamp, doesn’t ask me any questions, doesn’t say anything; he just stamps my papers “REJECTED,” and hands me my 4-F paper, still looking at his desk.

So I went out and got on the bus for Schenectady, and while I was riding on the bus I thought about the crazy thing that had happened, and I started to laugh—out loud—and I said to myself, “My God! If they saw me now, they would be sure!”

When I finally got back to Schenectady I went in to see Hans Bethe. He was sitting behind his desk, and he said to me in a joking voice, “Well, Dick, did you pass?”

I made a long face and shook my head slowly. “No.”

Then he suddenly felt terrible, thinking that they had discovered some serious medical problem with me, so he said in a concerned voice, “What’s the matter, Dick?”

I touched my finger to my forehead.

He said, “No!”

“Yes!”

He cried, “No-o-o-o-o-o-o!!!” and he laughed so hard that the roof of the General Electric Company nearly came off.

I told the story to many other people, and everybody laughed, with a few exceptions.

When I got back to New York, my father, mother, and sister called for me at the airport, and on the way home in the car I told them all the story. At the end of it my mother said, “Well, what should we do, Mel?”

My father said, “Don’t be ridiculous, Lucille. It’s absurd!”

So that was that, but my sister told me later that when we got home and they were alone, my father said, “Now, Lucille, you shouldn’t have said anything in front of him. Now what should we do?”

By that time my mother had sobered up, and she said, “Don’t be ridiculous, Mel!”

One other person was bothered by the story. It was at a Physical Society meeting dinner, and Professor Slater, my old professor at MIT, said, “Hey, Feynman! Tell us that story about the draft I heard.”

I told the whole story to all these physicists—I didn’t know any of them except Slater—and they were all laughing throughout, but at the end one guy said, “Well, maybe the psychiatrist had something in mind.”

I said resolutely, “And what profession are you, sir?” Of course, that was a dumb question, because we were all physicists at a professional meeting. But I was surprised that a physicist would say something like that.

He said, “Well, uh, I’m really not supposed to be here, but I came as the guest of my brother, who’s a physicist. I’m a psychiatrist.” I smoked him right out!

After a while I began to worry. Here’s a guy who’s been deferred all during the war because he’s working on the bomb, and the draft board gets letters saying he’s important, and now he gets a “D” in “Psychiatric”—it turns out he’s a nut! Obviously he isn’t a nut; he’s just trying to make us believe he’s a nut—we’ll get him!

The situation didn’t look good to me, so I had to find a way out. After a few days, I figured out a solution. I wrote a letter to the draft board that went something like this:

Result: “Deferred. 4F Medical Reasons.”