'Los Alamos from Below' -- recollections by Feynman

[AdamSmith]

Lacking an explicit Nerd forum , herewith...

Los Alamos From Below: Reminiscences 1943-1945, by Richard Feynman

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.

So I want you to just imagine this young graduate student that hasn't got his degree yet but is working on his thesis, and I'll start by saying how I got into the project, and then what happened to me.

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 fellows 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 the process of what we were doing, 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 would be perfectly right. Another guy would say, well, maybe, but there's this other possibility we have to consider against it.

I'm jumping! Compton should say it again! So everybody is disagreeing, all around the table. 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 fellow 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. So that was a shock. 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 fellows 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 that way?" In half an hour he had it solved, and they'd been working on it for three months. So, I did something! 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.

I had a lot of interesting experiences with Bethe. The first day when he came in, we had a calculator, or glorified adding machine, a Marchant that you work by hand. And so he said, “Let's see." The formula he'd been working out, he says, “involves the pressure squared; the pressure is 48; so the square of 48 is --

I reach for the machine.

He says, “It's about 2300.” So I plug it out just to find out.

He says, “You want to know exactly? It's 2304." And it came out 2304.

So I said, “How do you do that?"

He says, “Don't you know how to take squares of numbers near 50? If it's near 50, say 3 below (47), then the answer is 3 below 25 - like 47 squared is 2200, and how much is left over is the square of what's residual. For instance, it's 3 less and the square of that is 9, so you get 2209 from 47 squared."

So he knew all his arithmetic, and he was very good at it, and that was a challenge to me. I kept practicing. We used to have a little contest. Every time we'd have to calculate anything we'd race to the answer, he and I, and I would lose. After several years I began to get in there once in a while, maybe one out of four. You have to notice the numbers, you see - and each of us would notice a different way. We had lots of fun.

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 Christie and his wife had to go to the bathroom through our bedroom. So that was very uncomfortable.

The next place we moved to was called the Big House, which had a balcony all the way around the outside on the second floor, where all the beds were lined up next to each other, along the wall. Downstairs there was a big chart that told you what your bed number was and which bathroom to change your clothes in. Under my name it said "Bathroom C"' but no bed number! By this time I was getting annoyed.

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. Now my wife was sick with TB in Santa Fe, 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. OK? 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 says.

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! Shaking, she doesn't know what to do. 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? 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 then up, and see what happens." OK? Next day, same report. For four days, they worried up there about what they're 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 don't like the way things are 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, “ Yah, 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 TWIX3."

"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 do, 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 each other straightened out. Anyway, one day I'm piddling around with the computing machine, and I notice something very peculiar. If you take 1 divided by 273 you get .004115226337... It's quite cute, and then it goes a little cockeyed when you're carrying; confusion occurs for only about three numbers, and then you can see how the 10 10 13 is really equivalent to 114 again, or 115 again, and it keeps on going, and repeats itself nicely after a couple of cycles. 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 273 you do, in fact, get all that, and therefore there's no more information in the number .004115226337... than there is in the number 273 - 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. OK?

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 begins to wonder what's 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 71 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.

Well, 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, “Well, I don't keep my most important secrets in my filing cabinet; I keep them in my desk drawer. Isn't that better?"

I said, “I don't know. I haven't seen your desk drawer.”

Well, he 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. OK?

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

After I was able to open the filing cabinets by picking the locks, they got filing cabinets that had safe combinations. Now, one of my diseases, one of my things in life, is that anything that is secret I try to undo. And so the locks to those filing cabinets represented a challenge to me. How the hell to open them? So I worked and worked on them. There are all kinds of stories about how you can feel the numbers and listen to things and so on. That's true; I understand it very well -- for old-fashioned safes. But these had a new design so that nothing would be pushing against the wheels while you were trying them, and none of the old methods would work.

I read books by locksmiths, which always say in the beginning how they opened the locks when the safe is under water and the woman in it is drowning or something, and the great locksmith opened the safe. And then in the back they tell you how they do it, and they don't tell you anything sensible. It doesn't sound like they could really open safes that way - like guess the combination on the basis of the psychology of the person who owns it! So I always figured they were keeping the method a secret, and like a kind of disease, I kept working on these things until I found out a few things.

First, I found out how big a range you need to open the combination, how close you have to be. And then I invented a system by which you could try all the necessary combinations - 8,000, as it turned out, because you could be within two of every number. And then I worked out a scheme by which I could try numbers without altering a number that I had already set, by correctly moving the wheels, so that I could try all the combinations in eight hours. And then finally I discovered (this took me about two years of researching) that it's easy to take the last two numbers of the combination off the safe if the safe is open. If the drawer was pulled out, you could turn the number and see the bolt go up and play around and find out what number it comes back at, and stuff like that. With a little trickery, you can get the combination off.

So I used to practice it like a cardsharp practices cards, you know - all the time. Quicker and quicker and more and more unobtrusively I would come in and talk to some guy. I'd sort of lean against his filing cabinet, and you wouldn't even notice I'm doing anything. I'm not doing anything - just playing with the dial, that's all, just playing with the dial. But all the time I was taking the two numbers off! And then I would go back to my office and write the two numbers down, the last two numbers of the three. Now, if you have the last two numbers, it takes just a minute to try for the first number; there's only 20 possibilities, and it's open. OK? It takes about three minutes to open a safe if you know the last two numbers.

So I got an excellent reputation for safe-cracking. They would say to me, “Mr. Schmultz is out of town, and we need a document from his safe. Can you open it?"

I'd say, “Yes, I can open it, but I have to go get my tools.”

I didn't need any tools, but I'd go to my office and look up the number of his safe. I had the last two numbers for everybody's safe in my office. I'd put a screwdriver in my back pocket to account for the tool I claimed I needed. I'd go back to the room and close the door. The attitude is that this business about how you open safes is not something that everybody should know because it makes everything very unsafe. So I'd close the door and then sit down and read a magazine or do something. I'd average about 20 minutes of doing nothing, and then I'd open it. Well, I really opened it right away to see that everything was all right, and then I'd sit there for 20 minutes to give myself a good reputation that it wasn't too easy, that there was no trick to it. And then I'd come out, sweating a bit, and say, “It's open. There you are."

Once, however, I did open a safe purely by accident, and that helped to reinforce my reputation. It was a sensation, but it was pure luck.

I went back to Los Alamos after the war was over to finish some papers, and there I did some safe opening that - well, I could write a safecracker book better than any previous safecracker book. It would start by explaining how I opened the safe - absolutely cold, without knowing the combination - which contained more secret things than any safe that's ever been opened. I opened the safe that contained the secret of the atomic bomb - all the secrets, the formulas, the rates at which neutrons are liberated from uranium, how much uranium you need to make a bomb, how much was being made and available, all the theories, all the calculations, the WHOLE DAMN THING!

This is the way it was done.

I was trying to write a report. I needed some material but it was a Saturday. I thought everybody worked. I thought it was like Los Alamos used to be. So I went down to get some documents from the library. The library at Los Alamos had all these documents in a great vault with a lock and dial of a kind I didn't know anything about. Filing cabinets I understood, but I was an expert only on filing cabinets. Not only that, but there were guards walking back and forth in front with guns. I couldn't get that vault open. OK?

But then I thought, wait! Old Freddy DeHoffman is in charge of deciding which documents now can be de-classified. He had to run down to the library and back so often, he got tired of it. And he got a brilliant idea. He would get a copy made of every document in the Los Alamos library. And he'd stick them in his files. He had nine filing cabinets, one right next to the other in two rooms, full of all the documents of Los Alamos.

I went up to his office. The office door was open. It looked like he was coming back any minute; the light was lit. So I waited. And, as always when I'm waiting, I diddled the knobs. I tried 10-20-30 - didn't work. I tried 20-40-60 - didn't work. I tried everything, because I'm waiting, with nothing to do.

Then I began to think. You know, I have never been able to figure out how to open safes cleverly, so maybe those locksmith people don't either. Maybe all the stuff they tell me about psychology is right. I'm going to open this one by psychology.

The first thing the book says is: "The secretary is very often nervous that she will forget the combination.” She's been told the combination, but she might forget, and the boss might forget. She has to know. So she nervously writes it somewhere. Where? List of places where a secretary might write combinations, OK? It starts right out with the most clever thing: You open the drawer, and on the wood along the outside of the drawer is written carelessly a number, as if it is an invoice number. That's the combination number. So. It's on the side of the desk, OK? I remembered that; it's in the book.

The desk drawer was locked, but I picked the lock easily. I pulled out the drawer, looked along the wood. Nothing. All right, all right. There were a lot of papers in the drawer. I fished around among the papers, and finally I found it, a nice little piece of paper which has the Greek alphabet - alpha, beta, gamma, delta, and so forth - carefully printed.

The secretaries have to know how to make those letters and what to call them when they're talking about them, right? So they each had a copy of the thing. But - carelessly scrawled across the top is, pi is equal to 3.14159. Well, why does she need the numerical value of pi? She's not computing anything. So I walked up to the safe. 31-41-59 - doesn't open. 13-14-95 doesn't open. 95-14-13 - doesn't open. For 20 minutes I turned pi upside down. Nothing happened.

So I started walking out of the office, and I remembered in the book about the psychology, and I said, “You know, it's true. Psychologically, DeHoffman is just the kind of a guy to use a mathematical constant for his safe combination. And the other important mathematical constant is e.” So I walk back to the safe. 27-18-28 - click, clock, it opens.

I checked, by the way, that all the rest of the filing cabinets had the same combination.

Well, I want to tell about some of the special problems I had at Los Alamos that were rather interesting. One thing had to do with the safety of the plant at Oak Ridge. Los Alamos was going to make the bomb, but at Oak Ridge they were trying to separate the isotopes of uranium - uranium 238 and uranium 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 practising 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 - and though we would send them instructions, they never got it right.

So finally 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 says, “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 says.

Huh! Explode?

And so the Army said, “You see! We shouldn't have let any information get to them! Now they are all upset.”

Well, it turned out that the Army had realized how much stuff we needed to make a bomb -- 20 kilograms or whatever it was - and they realized that 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. And so 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. So, 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. Christie'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 Christie 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 Christie, and said, you have all the stuff, so go. Christie got pneumonia; I had to go.

I never traveled on an airplane before. I traveled on an airplane. 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. ”It looks like this. There are some generals coming. They are going to put off some of us number 3's.”

"It's all right, “ I said, “I'm a number 2."

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 2 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 short-term 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 home that night, and I 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 be made safe, so that they really understand.”

I said, “What if they're not at the meeting? What am I supposed to do?"

He said, “Then you should say: Los Alamos cannot accept the responsibility for the safety of the Oak Ridge plant unless ___!"

I said, “You mean me, little Richard, is going to go in there and say -? "

He said, “Yes, little Richard, you go and do that."

I really grew up fast!

So 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. And that was good because the plant would have blown up if nobody had paid attention to this problem.

Well, there was a Lieutenant Zumwalt who took care of me, and 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. So it's my opinion that it's only going to work if I tell them, and Los Alamos cannot accept the responsibility for the safety of the Oak Ridge plant unless they are fully informed as to how it works!"

It was great. 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 or not had to be decided and could be decided in five minutes. So I have a great deal of respect for these military guys, because I never can decide anything very important in any length of time at all.

So in five minutes he said, “All right, Mr. Feynman, go ahead."

So I sat down and I told them all about neutrons, how they worked, da da, ta ta ta, there are too many neutrons together, you'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 turned out to be a tremendous genius to them.

I was a god coming down from the sky! Here were all these phenomena that were not understood and never heard of before - but I knew all about it; I could give them facts and numbers and everything else. So, from being rather primitive back there at Los Alamos, I became a super-genius at the other end.

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 re-design 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. OK?

How do you look at a plant that ain't built yet? I don't know. Well, 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 cover, a stack of large, long 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 start to explain it to me, because they think I am a genius. Now, one of the things they had to avoid in the plant was accumulation. So 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, down-up-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?"

I don't know what to do. (You are not going to believe this story, but I swear it's absolutely true - it's such sensational luck.) I thought, what am I going to do? I got an idea. Maybe it's a valve? So, in order to find out whether it's a valve or not, I take my finger and I put it down on one of the mysterious little crosses in the middle of one of the blueprints on page number 3, 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 up and down, back and forth, back and forth, and they both look at each other and they tchk, tchk, tchk, and 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.

Well, 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. So 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 explosion, so you can figure out exactly how much energy was released and so on - required much more calculating than we were capable of. A rather clever fellow by the name of Stanley Frankel realized that it could possibly be 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. But she was the multiplier, and she was the adder, and this one cubed, and we had index cards, and all she did was cube this number and send it to the next one.

We went through our cycle this way until we got all the bugs out. Well, 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. So 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.

And so 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 arctangent 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.

And so 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 - and so forth.

So my boys really came through, and all that had to be done was to tell them what it was, that's all. 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 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 Christie 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."

So 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 there was nothing else 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 died in Albuquerque, and I had to go down. I borrowed Fuchs' car. He was a friend of mine in the dormitory. He had an automobile. He was using the automobile to take the secrets away, you know, down to Santa Fe. He was the spy. I didn't know that. I borrowed his car to go to Albuquerque. The damn thing got three flat tires on the way. I came back from there, and I went into the room, because I was supposed to be supervising everything, but I couldn't do it for three days.

It was in this mess. There's white cards, there's blue cards, there's yellow cards, and I start 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 50 cards and you make a mistake at card number 39, it affects 37, 38, and 39. The next, card 36, 37, 38, 39, and 40. 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 10 cards around the error. And because 10 cards could be put through the machine faster than the deck of 50 cards, they would go rapidly through with this other deck while they continued with the 50 cards with the disease spreading. But the other thing was computing faster, and they would seal it all up and correct it. OK? Very clever.

That was the way those guys worked, really hard, very clever, 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. So I left them alone and everything came out. We solved the problem in time and that's the way it was.

I would like to tell a little about some of the people I met. I was an underling at the beginning. I became a group leader. But 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, 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. So that was quite a lesson to me.

Then there was Von Neumann, the great mathematician. We used to go for walks on Sunday. We'd walk in the canyons, and we'd often walk with Bethe, and Von Neumann, and 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, from the corner.

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

"Hello - Feynman?"

"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. OK."

So, at 8 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. Blah, blah, 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."

So forth, back and forth. I was always dumb about one thing. 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. Just as I was lucky with that blueprint, I'm lucky in my life that I can do this.

So, 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 says 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, he 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."

The next thing that happened, of course, was the ' I 'test, after we'd made the calculations. 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 just arrived when the buses were leaving, so I went straight out to the site and we waited out there, 20 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 20 seconds or something to go, for people who were far away like we were. Others were closer, 6 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. OK.

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 ain't it. That's an after-image.” So I look back up, and I see this white light changing into yellow and then into orange. The clouds form and then they disappear again; the compression and the expansion forms and makes clouds disappear. Then 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 of the fire going out, the heat.

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 Mr. 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's kicking the doorstop, you see, and I said, “Yes, the doorstop certainly is appropriate for this door.” The doorstop was a 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. So 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 anymore, 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 St? ... 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 about 30 years now, isn't it? So I've been wrong for 30 years about it being useless making bridges and I'm glad that those other people had the sense to go ahead.

"Los Alamos From Below'' has been adapted from a talk given by Richard P. Feynman, Richard Chace Tolman Professor of Theoretical Physics at Caltech, in the First Annual Santa Barbara Lectures on Science and Society, given at the University of California at Santa Barbara in 1975. This was one of nine lectures presented in a series of "Reminiscences of Los Alamos, 1943-1945." The lectures are now being edited for publication by Dr. Lawrence Badash of the Department of History, UCSB.

http://calteches.library.caltech.edu/34/3/FeynmanLosAlamos.htm

[RA1]

I am the Canal Street Fairy, will I do?

Best regards,

RA1

[MsGuy]

Fascinating essay.

But don't you think it would be better to tell your readers a little something about Richard Feynman?

[lookin]

a little something about Richard Feynman?

Feynman has been called the "Great Explainer". He gained a reputation for taking great care when giving explanations to his students and for making it a moral duty to make the topic accessible. His guiding principle was that, if a topic could not be explained in a freshman lecture, it was not yet fully understood.

Thank you!

Apparently, he gave a series of lectures at my alma mater intended to make physics accessible to all. Sadly, I think it was the semester I flunked out since physics had not been measurably accessible to me.

[AdamSmith]

But don't you think it would be better to tell your readers a little something about Richard Feynman?

Surely you're joking!

https://books.google.com/books?id=7papZR4oVssC&printsec=frontcover&dq=surely+you%27re+joking+mr+feynman&hl=en&sa=X&ei=TR8FVaHvGISWgwTwtIGYCg&ved=0CCcQ6AEwAA

[AdamSmith]

Long oral-history interview of Feynman on his core contributions to physics. Warning -- not quite the light bagatelle of the original post above, but riveting of its kind:

http://www.aip.org/history/ohilist/5020_3.html

[AdamSmith]

So those oral-history transcripts from Feynman are a lot more fun than I had expected. At random:

...I’m still at Cornell, definitely, right. Good. That’s all right. Well, I went to Princeton, to the Institute of Advanced Study, and there were these smart people there, and they came to the lecture, and I explained it, explained the ideas. And I always had the impression at the Institute — Well, I gave the lectures, and it was very successful. All the questions were very practical. And very sensible. And I was rather terrified of the Institute before that, because it was well known that all these guys at the Institute would talk a good game, you see. Like somebody would say, “Well, isn’t that just the same as Smorglepop’s theory?” I’ll give you another example of it in a minute. At any rate, I gave the lectures, and there were nothing but practical questions like, “If you were trying to do this problem, how would you set it up? Did you mean by this a minus sign there?” “Yes” You know. All perfectly OK, and I gave nice lectures. I gave all the lectures I wanted to and explained everything and went back home to Cornell. I said: “Hey, Hans, the Institute has changed! Something has happened. These guys are very different. They didn’t ask anything but sensible questions. They didn’t say, ‘Isn’t that the same as Porkyschnorp in 1621?’ or something like that.” “Oh,” he said, “I know the reason. I went just a few weeks before you did and gave some lectures on nuclear physics. I started to give the lectures and I hadn’t opened my mouth and said two, three, four words, when this stuff started. Somebody jumps up and asks a question. He says, ‘Isn’t that the same as what Wegischnorp said in 1960, and so on, in a paper in the Weische Physica Acta?’ Somebody else, before I can answer, gets up (typical Princeton Institute) and says, ‘No, you see, what Bethe is going to say is ‘this, that and the other thing,’ and what the fellow says in the Weische Physica Acta is ‘this, slightly different.’ And somebody else says, ‘No, it isn’t exactly so different, because Bethe —’” He says to me, “So when the third fellow gets up to argue, I slam the table” — you know, when Bethe gets mad he can look formidable -– “I slam the table and I said, ‘Gentlemen, if you knew what I was going to say, why did you invite me to speak? Now, I want to make an uninterrupted speech, unless you have a specific, detailed, and sensible question.’” Then he gave his lecture. When I followed, they were still smarting under the spanking that they had gotten from Hans, you see. So they were asking only sensible questions. I was afraid that they would just try to tear me limb from limb — you know, saying “This is just Schwinger stuff. You can do it this way. Why don’t you do it that way? Why don’t you do it this way?” And then quoting some other guys, and making it very esoteric and difficult and fancy. They have a kind of one-upmanship which practical people can see through, but which a poor fellow is fooled by. I wouldn’t have been fooled by it, but I would have been terribly annoyed by it, because they wouldn’t have been learning from me. They wouldn’t have been paying attention if they’d started that game. They close their minds to find out if it isn’t the same as something they already know. Therefore, they don’t have to learn it. So at any rate, that was my opinion of the Institute, but I had, I must admit, no trouble whatever, and they were a very, very good audience. They listened and asked only sensible questions.

http://www.aip.org/history/ohilist/5020_3.html

[AdamSmith]

... we got this space-time view, this view of action integrals and action in distance, and pads in space and time instead of fields, and so on, that we were thinking about. Then Wheeler called me up one day and he said I answered the phone in my dormitory - Feynman, I know why all the electrons have the same charge and mass, all different electrons. I said, Why? He said, Theyre all the same electron. So I asked him what he meant by that brilliant idea. He said, You know, we always make the world lines go one way, but suppose the world line of an electron is one enormous knot, going back and forth in space-time, just one line, going back and forth. Then when we cut it in the place of present time, wed have a large number of intersections, which would represent electrons. I said, Oh. Yeah. Very nice. He said, It turns out that the back section, where its going the other way, the proper times running the wrong way, corresponds to a negative charge. You see why? Then he explained why. I could see it from our action principle: you change the sign of BS and change the sign of the charge. So that was I said, Yeah, but where are all the positrons? Well, maybe theyre hidden in the protons somewhere or something, the back sections. I said, Ok. Its a nice idea. But what I liked about the idea was that the positrons were electrons going backwards in time, and that world lines could be inverted. This idea I kept in my mind, although I didnt go so much for the fact that all electrons are the same electron. He always liked to prove it to the most dramatic point. I just took the backwards-moving electrons as very likely candidates for the positrons. Because here we had a theory that we could represent both electrons and positrons in classical physics in a very simple way, by reversing, by letting the world lines go backwards and forwards in time. So it was pretty good. He had a lot of good ideas, Wheeler.

Weiner:

Yeah. He seemed to be able to deal with the ones that you brought in too.

Feynman:

Yes. Well, what he did, you see, things like Id like to remark that the moment he mentioned advanced waves that is, against causality and all this other stuff is against cause, the causes would precede the effect no, the causes would follow the effects instead of preceding them, and so on I didnt ever say, But thats impossible! or anything like that. I was not ever upset by any of the obvious troubles, as against some principle of causality or something. This was from the training we had in physics from Einstein and Bohr and so on. See, the history of physics was that a crazy idea like relativity, which is so evidently nutty like when one man thinks two things are simultaneous, some other guy riding by doesnt say so or, that you cant measure simultaneously position and momentum, or something It had been discovering that you must always think carefully about the real experimental situation before you cavalierly say such a thing is impossible, you dont like it. So I never objected to any of these crazy ideas, on those grounds. I never said, for instance, How can it go backwards? How would it know when its going to meet an electron? I knew that that was something we would have to study that that wasnt obviously cockeyed. The fact that there were protons and not positrons were an obvious trouble, but I let him get away with it, so someday well discover how the protons go, wind up in this knot, too. But never mind. His brilliance, the wildness of his ideas, apparently impossible ideas, did fall on fertile soil, because I never objected to what other people would immediately have objected to, you know. All the books would say we cant use advanced waves because this would mean effects would precede causes. But things like that never bothered me. I dont give a darn. I never thought in terms of cause and effect necessarily, anything.

http://www.aip.org/history/ohilist/5020_3.html

[AdamSmith]

Feynman:

I don’t know maybe an afternoon. And Bohr came up and apologized. His son had told him that he didn’t understand it, that I really was consonant with the principles of quantum mechanics. But I said, “It’s not necessary to apologize,” — you know, something like that. After that, I don’t know what I did. I didn’t do any more, but just decided to publish it. There is one little thing, though, that’s interesting, that also added to the complications. When I got up to talk, I started out by saying, “I can do everything but I can’t do the closed loops, the self-energy of the electron, I mean the vacuum polarization.” Schwinger got up and said, “I can do everything, including the vacuum polarization.” And he worked something out, and he got a term which looked like vacuum polarization. He had to subtract, and it left the vacuum polarization. It later came out that he had not done the vacuum polarization, but he had left it out — he didn’t even notice the term — and he had another term that he’d been doing, and was doing it wrong. And it looked like a vacuum polarization correction, the error, which you could get rid of by saying he had vacuum polarization. He got rid of it. Well, I was doing it more right, and didn’t have any vacuum polarization term at all, and knew it was missing, and said it was missing — whereas, he thought he had it and included it and got it right. But neither of us knew how to do it. But we didn’t know it. He said he did. And I said I didn’t do it. So one of the criticisms they gave was, “Why should we bother with this, you haven’t done the vacuum polarization yet. And the other thing is all done.” So you see, that was another, a small thing. I’m just saying it wasn’t something that bothered me. It didn’t bother me. I’m just telling the difficulties that people have in paying attention to me. They thought I hadn’t as much as he had — actually, I happened to have more but I didn’t know it — and so on. I could describe the specific terms, but one time a few weeks later, when I was visiting MIT, Schwinger called me up and said, “According to what I understood from what we were discussing, the terms which you have included give no vacuum polarization term, and that you have this extra thing. Well, now I found this extra thing. But now what bothers me is that the terms which I thought I had, which were the same as yours — I have a correction, it looks like a charge correction from those terms, and you said you had none. How did you handle them?” So I had to discuss terms on the telephone. We could do it. And I explained to him which terms would cancel what, and he hadn’t noticed those. “Oh,” he said, “I forgot to put those in.” So he put them in, corrected the thing, and got the same result. So, you see, we understood each other. We corrected each other. You know, we each fixed the other up, by pointing things out to each other at the time. So we were cooperating very well. But it was hard for us to know exactly what we were doing, and we would sometimes misrepresent the situation a little bit.

Weiner:

You could even talk about this on the phone?

Feynman:

Even on the phone we could identify the terms, I remember, because we understood what we were doing. We could visualize. I would say, “The term I’m talking about is canceled by a term which comes from a photon which is first emitted before interaction with the nuclear potential, is first emitted and then absorbed before the interaction with the nuclear potential.” And he’d say, “But that’s just a mass correction.” I’d say, “No, because of the fact, the mass correction is when there’s a free particle, and because of the fact that a potential is going to act soon, there’s a slight correction near the end point of the integral.” “Oh, yeah!” You know? So it would go something like that. We could talk on the telephone to each other. We understood each other very well.

http://www.aip.org/history/ohilist/5020_3.html

[AdamSmith]

[At Los Alamos] Anyhow, we did start to work and things improved a little. We got chairs and desks and filing cabinets and this and that, rather rapidly, and blackboards and so on. But in the first few weeks — there were many men I had heard of, you know, like Teller, Weisskopf — I don’t know how many I had ever met, exactly, but if I met them all I met them only from a distance or quickly, like Bethe was there. I’d only met him a little bit before, you know — not really met him, seen him — and there were all these great minds and great names that I knew of. They were great people. When I got up there, in the second or third week (I can’t remember exactly) there was a kind of accident, that all of the important men had to leave. Weisskopf had to go back to check something, he was selling his house or something. Teller was out because of something. Everybody was away except Bethe, who was the head of the theoretical division, and Bethe apparently needed somebody to talk to when he had an idea to make it was Ok. He wandered around. He went into my office. We’d never met before, but he couldn’t find anybody, and be started to explain his idea. I’m kind of dopey — just like it happens in the lecture that I gave where I was nervous but the moment I started to talk physics, I’m only thinking physics —

Weiner:

You mean that lecture in the first colloquium at Princeton?

Feynman:

Right. The same thing always happens to me when I’m thinking physics. I’m 100 percent involved. So he started to talk a little bit, and when he would tell me something, I’d start thinking, and I’d say, “No, that’s crazy, you see —” Without thinking, who am I talking to? or anything. “Crazy” and he’d say “Why?” and I would explain — he’d say, “No, you see, you’re wrong,” and he’d explain back, and of course I was wrong. This went on again and again, and I kept saying these things and he’d point out I was wrong and so on. Finally he went out of the office. Then I kind of woke up, you know. I said, “My God, what am I doing? I’ve told him he was wrong a million times and I was wrong every time?” But apparently that’s just what he wanted. He wanted someone who, he felt, was checking, really checking the thing. And none of these guys are really worried if you tell them they’re crazy. They argue only on the physics, not on the human. So apparently he was very happy with this, and he kept coming into my office. Then when the other guys come back, we had a good relationship, Bethe and I. He would still discuss things with me a lot. So I kind of was lucky in that respect, you know. We discussed many things of this kind. At the beginning I was always wrong. After a while, once in a while I would catch him out, but usually not. People used to say that to hear the two of us talking was to watch a battleship and a mosquito boat, because he would plow through the subject slowing, uniformly, correctly and so on, not deflected in the one direction or the other, working something out, while I would jump to conclusion –- “No, no, wait a minute, that’s wrong, let it go like this,” and so on. Once in a while I’d bump into something that he heading for, but usually he was going all right, you know. It was amusing. Anyway, I wanted to mention that relationship, which was quite close, and we always discussed many things together.

http://www.aip.org/history/ohilist/5020_2.html

[AdamSmith]

I was very good at doing integrals, and, for a reason that I don’t know, especially good at doing numerical calculations. I knew how to organize arithmetic so that you did a minimum amount of work to get the answer, and apparently that talent is not very widespread. I didn’t know that until I got there. Because, on the way home from lunch often, I would walk through the computing division, the computing department. See, the theorists in different groups would give problems to the computing department. I would walk through the computing department and look over the shoulder of a girl and say, “That’s wrong, that number.” Things like that, you see. Or I’d go through and say, “What are you doing?” and they’d explain. I’d say, “That’s not the way to do that problem,” and I’d go to the guy who gave it and explain to him a way of doing it five times faster. You’d think a guy like this would be annoying, but no, everybody liked it. Anyway you could improve was all right, it didn’t make any difference. There were no personal difficulties, you see. If I’d say “It’s wrong” it was to help, and everybody knew it. It was no problem. So I used to be able to do this, go around the computing department. One of the (for me) most amusing things was, a man was trying to work out an integral differential equation, complicated thing — the third root of something is a complicated integral, with a kernel and everything, an integral equation with derivatives, and he was integrating this three times, because the third derivative by Simpson’s rule — but he had to first calculate this integral kernel, many integrals — a long and elaborate thing. I looked at the kernel and I noticed that that operation was the one-half derivative. You remember I told you that I’d worked out that from before? I’m just telling you the connection. I looked — one-half derivative — so I figured, his equation is a non-linear 3 1/2 order differential equation; it said, “the 3 1/2 derivative of U is U squared,” that’s all there was to it. So I figured: Now, look, there’s numerical ways of doing one integration, Simpson’s rule — of doing a double integral, doing triple integral, see. Is there a way? Or at least there was of single integral and maybe double, you could invent them. What about inventing a numerical method of doing half an integral? So I cooked up a numerical scheme for doing half an integral in one step. Then to do three integrals, the three integrals which he did by Simpson’s rule in succession, I made up a new numerical rule to do three integrals in succession and extrapolate to the next point, and it turns out by some freakish accident that the numerical method is one order higher or two orders higher than it ought to be. You see, in any numerical method you are doing some polynomial to approximate the curve. Then the error is the first degree of polynomial that’s higher than the number of points that you’ve taken. You can’t fit. Well, there’s an error that comes when there’s one higher order derivative. It has a coefficient, such as Simpson’s rule, the 4th derivative times 1 over 180 times the integral to the 4th or something. Well, the thing that would correspond to 1 over 180 for this problem was zero. It was accident that with this particular method, the coefficient of the error was zero, and it was much more accurate. So that was cute, that three times integration extrapolated can be done so accurately, and that was not known before. And the numerical way of doing the half integral was very amusing. I got a terrific kick out of that, and ended up inventing a numerical method to do the problem, a special problem, but this is the kind of thing that’s not generalizable. But it was so much more efficient that in spite of the work I did to find the method, develop it, explain it and do it, I got way ahead of the guys that were doing it slowly. And they just stopped, because they had this other scheme.

Weiner:

Do you consider this as play, really?

Feynman:

Yes, a great deal of it is play, you see. I mean, I look for problems and I do things. I know, but play that was contributing, you see, and not fiddling around. I never fiddled around there. I played a lot, but I always played in a way that was directed. I could always explain the play as not useless, you see. There was a tremendous amount of play. That’s really what it was — so many problems — I’d look for them, because I liked all these crazy things. Yes, very much like play. But always with a purpose in the end.

http://www.aip.org/history/ohilist/5020_2.html

[AdamSmith]

They began to be able to produce a little bit of separated isotopes from the plant in Tennessee, sort of on an experimental basis. And they had made surveys, I mean tests, of the proportions, of the degree of separation. They had calibrated the degree of separation at Tennessee. Then they would send us the samples, and Segre and the others who received them would measure the proportions, and it didn’t agree. We were just getting tiny little samples to do experiments with that they had separated in their attempts to test their equipment before they put 200 of them together, you see. That was the stage. The plants were getting ready, but sort of pilot experiments were being done with the equipment, you see. And it didn’t check. They had many things back and forth that didn’t check. Finally Segre and company said, “We can’t straighten this out unless we go down there and find out what they’re doing to make the test. They’re doing something wrong, and we can’t do it by mail,” and so on. This was very much against the rules. See, the Army’s rules, or Mr. Groves’ or something was one department like Tennessee does not have to know what’s going on at Los Alamos or anything about the bomb. They just separate the uranium. And the other side, we’ll tell them anything they need to know, the other side, Los Alamos, doesn’t have to know how the plant works, what it looks like or anything. It was the secrecy. It sounded like a good idea. But there was this problem of communication. So finally it was broken down. Oppenheimer or somebody helped to break down this so that they would be able to go to Tennessee to talk to those guys, rather than the other way, because the secrecy was much more important. So they went, Segre and two or three other guys, went, and as they were walking through the plant, they see a little bit of what the plant is like. And the guys are practicing already. They haven’t got the thing separated yet, but they’re practicing with the chemical process and so on, where it was partly built, and they’re partly going through the motions of the operations. And they see great barrels of bluish-green water being carried on dollies and so on, boxes, and cardboard boxes with salts of various kinds stored in a room — and while they see it they say, “What’s that stuff? Is that uranium?” “Yeah.” “Well, when your plant gets operating, you’re going to separate it, you’re not going to handle it like that, are you, partly separate it…” They said, “Sure, why not.” “Won’t it explode?” they said innocently. And this caused a terrible excitement, you see. Well, to make the story shorter, they didn’t know, in Tennessee. They had been told that there was no danger whatsoever. Segre saw these bottles of water with this stuff in it — realized, of course, as we all do, that when you put it in water, because it slowed down the neutrons and made them much more effective, you’d need very much less stuff, and so on. He realized that there was a danger. And he didn’t think that they didn’t know that there was a danger, you see. The Army’s first reaction was: “It just shows you we shouldn’t let these guys in.” But their second reaction was to wake up. The point was, they had been told that it wouldn’t explode because presumably, my guess is, that they had been told how much stuff we needed for a bomb, which would be worked dry and very efficiently to get as much energy out as possible, not to get the reaction to go at all, and so on — not just to get the reaction to go. The Army, then, hearing that number, simply said, “It’s so big they’re never going to get all that in one barrel, there’s no danger.” But the fact is that with water solutions and other chemical solutions, you could accumulate stuff to explode. So there was a great moment of excitement just prior to the plant beginning to operate, when it was discovered that a new thing had to be worried about, the safety. Ok? I just set the situation up. Well, Segre was then authorized by Oppenheimer to go through the entire plant and make a list of all possible accumulation points where there might be danger. So he and his cohorts (I don’t remember who they were) made this thing and sent back to Los Alamos. See, it was an emergency problem for us, and we were set. I remember getting this thing and looking it through. Then we had a division of labor. Christy and his group calculated water solution, what the critical limits are, in the various circumstances, like in a plant — you know, what would happen if you mixed, how to do it, if you put cadmium in how much you would stop it. In some cases there was carbon tetrachloride. Well, the chlorine will absorb the neutrons and that’s OK. And all these questions of liquids. I was to calculate, in my group, the dry solids, the boxes full of salts, you see, against the brick walls — what were their limitations. You can get a lot more in a dry solid than in a liquid, and it was much harder to calculate, but anyway, that’s what we did, and we did it as fast as we could. But unlike calculating for the bomb, we took safety limits. It’s easier to calculate something that’s safe, than exactly what it is, you know. I mean, I can’t say 657 so and so’s going to explode. I can say, I know it isn’t going to explode with 302. You know? It’s much easier. You don’t have to be so accurate. So anyhow we got this all prepared. An emergency business — all work at Los Alamos, a lot of work in theoreticals, was stopped for a couple of weeks or so while we did this as fast as we could. We had to do it fast because the plant was getting ready to go, and they were not allowed to go until this thing was looked into, you see, so it was a very great and interesting emergency, very exciting. So Christy is going to go tell them about the thing, and I give my stuff to Christy, all my numbers, explain everything to him, and breathe a sigh of relief. Then he got pneumonia –- Christy — and was in the hospital, and I was going to have to go. So Christy gave me all his information about water and gave me my stuff back about solids, and said, “Good day.” Then I was sent across country to tell them about this thing. Oppenheimer said to me — before I left he called me up and said, “Now, about the safety thing, I want you to make sure that the following men are in the meeting when you first tell them the problem, because they’re the men there that know physics enough to understand. You tell them, the situation, what to do — but don’t directly tell the Army. Make sure that it’s not you telling the Army and the Army is going to be responsible, because they don’t know enough. I mean, they’re nice, but you’ve got to get somebody there who knows physics.” They gave me names, Webb and a few others, and so on, to do it. So I said: “Well, suppose they arrange a meeting and these fellows aren’t there?” “Well, you ask for them,” says Oppenheimer. “But suppose that they say no for some reason, secrecy or something?” He said, “Then you say, ‘Los Alamos cannot then accept the responsibility for the safety of the Oak Ridge Plant.’” I said, “You mean me, little Richard Feynman, is going to say that?” He said, “Yes, little Richard Feynman, you’re going to say that.” Growing up, yeah. So I got on the airplane to go across. I went by air. I’d never traveled by air before. (Just giving you the level, you know, the way it looks to the human end of it.) It was very exciting. You see, in that day we had to have priorities to fly. Then at one place, we’d fly, and we had to land — in those days you had to land in many places, like a bus trip, you know, as you went across. I think it was in Kansas City somewhere that we got off the airplane for a while, and then a lot of big important looking cats, some generals, important looking businessmen — and some guy’s standing there, swinging his gold watch round on a string, and he’s talking. I look like a kid, you know. And he says to me, “It must be extremely hard to fly without priorities in these days.” So I said, “Well, I don’t know. I have a priority.” So he’s still swinging. I mean, he was such an important what do you call it — the way he treated me, you know. He keeps swinging away, you know, he says, “Well, you know, some of us Number 4s are going to get bumped. I hear there are some generals getting on here.” Then I kind of leaned — I said, “That’s all right. I have a Number 3.” He probably wrote to his Congressman, “What are they doing? They give a priority to some kid.” Anyway, with all this information, I got to Oak Ridge. (I tell this just because it is very interesting to me.) I go to Oak Ridge, and the first thing, they asked me a lot of questions. “I’m not saying anything. I want to go through the plant. I want to see with my own eyes what I got on the report from Segre,” and so on. “Ok.” And I went through this plant. I discovered it was worse than they thought. There were a few things, like they would describe a room that had boxes of something; then they would describe another room that had barrels of something and another room that had bottles of something. Well, they had confusion going through the plant, because they were following the process. And it was the same room that they would go in several times. The boxes are on one side, the barrels on another. I am convinced that if they had simply started to separate the uranium, they would have had an accident. I don’t mean an explosion, but they would have had a nuclear reaction in some accumulation somewhere, relatively fast, and it would have made neutrons and radioactivity all over the plant, and there would have been a terrible calamity. I’m convinced of it, from the circumstances. Anyway, I went through the plant. I kept my trap shut. I didn’t go and say, “Oh, ah!” — nothing. I recorded everything in my mind, and that evening, I spent the whole night — I was practically awake the entire night — preparing for a meeting the next morning in which I would tell them the situation. I went through everything. I worked very hard on it. I have a fairly good short term memory, but not a good long term memory. When I work very hard on something I can remember it, and in all this stuff I remember the building numbers and the equipment numbers, you see, the tank No. 16 and building 9206 — because that’s the way they would tell it to me. “Now we’ll go into building 9206,” “This is tank so and so” — all this junk, this useless stuff, I would remember. I remembered it — for one day, is all — but when I was making my calculations and figuring and analyzing and so on, I thought in terms of this tank and that number and so forth. So I was very impressive the next day, when I could tell them that in tank no. 74 in building 9206 requires this, and can be repaired, and so on. It worked out very nicely. I made a big effect. While I did it, I prepared a kind of a speech in which I’d explain how the uranium underwent fission, how the neutrons came out, about slow neutrons and fast neutrons, what the effect of water was, why cadmium would slow the reactions, and so on — in order that they could understand how to be safe. I don’t believe — I didn’t believe it was possible to make the plant safe, under the circumstances, because it was a complete — It’s like you build something when nobody even knows there is such a thing as fire, and it evidently could have burnt up because there’s a flame standing there and there’s a piece of silk hanging over it, you see. You have to understand something about it to make it really stick. Well, the higher-ups had to understand — not just a series of arbitrary rules concocted by an expert from Los Alamos, but an understanding, for real safety. So the next day I came to go to the meeting. I had a lieutenant. They gave me a lieutenant to take me around all the time, Zumwalt or something, his name was. At the beginning of the meeting, Colonel Nichols said to me, through Zumwalt — he said to me that the Colonel said that he doesn’t want them to know anything about — it’s not necessary to tell them anything about the way nuclear reactions go, or something; just tell them what’s safe. So I reported. I said to the Colonel: “I do not feel that’s the way to do it, that it would be safe that way. It is necessary to give this information in order to make the plant safe, in my opinion.” I was ready, of course, for the next operation: “WE AT LOS ALAMOS CANNOT ACCEPT THE RESPONSIBILITY FOR THE SAFETY OF OAK RIDGE” — but I didn’t have to make that. Now, I was very impressed with these guys, colonels and generals. Very hard decision. The meeting is starting in five minutes. He goes to the window and looks out. They had never had this kind of exchange of information before. He asked for my opinion and I explained it. I explained why I had the opinion. He explained that it was dangerous that they should know this information. I explained that it was also dangerous if the plant didn’t work. You know? Not a long argument. I misrepresent it. It was three minutes. He goes to the window and looks out the window. He comes back. He says, “All right.” He makes the decision. I don’t know how they do it. Anyway, then the meeting started. I went through the meeting. I told them that the plant would explode. Why? I explained about neutrons, how everything worked, how it would explode, how it had to be redesigned, but it wasn’t very difficult. In the water solutions they could put a cadmium salt, if it doesn’t disturb the chemistry, and in this part of the chemistry it probably wouldn’t. That is a special problem. In that case we could surround it by a cadmium sheet. In this stuff we put boron solution, because cadmium would have an effect. “In Building 9216, in Tank 74, we can do it by doing this,” you see. “In such and such circumstances in the store room, we just have to get a bigger store room, and pack the boxes separated from one another, definitely, by building wooden platforms and so on, the way you put the boxes, so they can’t be stacked next to one another so you get too much in one place” — etc. So I told them the trouble, I told them the solutions. I told them, “some places I haven’t worked out the solutions,” and so on. It was a very exciting moment for me. This was the first time when I was telling anybody anything really, you know. It was a very important thing. So I was in a great and important position at that moment. After that I had to return to Tennessee from time to time, every month or so, to give advice, you see, to kind of confirm. Like, they had started some man to calculating himself. I had given him rules and formulas, so he could figure his own things out, and he wanted his hand held. I mean, they wanted his hand held, to make sure that he was doing it right, and this and that, so I had to go back and check. In addition, the company was building a new plant. It wasn’t ready yet. They were designing a plant for handling enriched material (a future plant) and with this stuff, the problem was even more serious. They had to separate things, and they had all these matters to take into account in design. So one time I returned — next time I returned to Tennessee, this company was ready with their new plans. They wanted me to check their plans, if they were safe. And one of the things we had to worry about was if valves jammed or something, like, say, an evaporator is evaporating the liquid from some uranium, so it keeps accumulating uranium, or if a valve gets stuck somewhere and stuff begins to pile up — you had to worry about all that. So they showed me these plans. They took me into a room, a room with a very long table — it must have been 15, 18 feet long and 5 or 6 feet wide — stacked with blueprints. The designers, the blueprint men, you know, the company men — they brought me into this room and they said, “Here’s the design. Now, we have designed this thing so that if any valve gets stuck — not one valve getting stuck alone would allow any accumulation. We always have a safety way,” and all this, it had been carefully worked out and so forth. Well, I had taken engineering drawing at MIT. I didn’t remember it too well. And here are these blueprints. Well, they got started fast, because I was so impressive the time before, and they thought I knew everything, you know: I knew all about neutrons, so I knew everything. Although lots of people knew about neutrons, for them, I was like a god. So they thought I knew everything, they started right in explaining about the plant — and here’s millions of lines on these things,” and so here, the plant goes down, and carbon tetrachloride goes up on the second floor,” and then they flipped a lot of paper up and they climbed down into the sheets of the blueprints –- “Here’s the second floor.” They go up and down. I’m trying to follow as fast as I can, and I notice — most of thing I understand, more of less — but all over the paper there’s a rectangle with a cross across it on the diagonal, and I don’t know what that is. So I’m thinking to ask, you know. Did you ever —? You must have gotten into this situation: you think to ask, and then you hesitate — maybe I can figure it out — and then the later it gets, the more they’ve told you, the more embarrassed you are to ask after they’ve told you all this stuff and it shows you weren’t understanding anything — you know? So I got in deeper and deeper. I got in more and more in trouble with this. I couldn’t ask. So finally I got an idea. I thought, “maybe it’s a valve” — I was guessing. (This is absolutely true — I’m just telling you, this is absolutely true, incredible but true.) I put my hand on one of those crosses to find out if it’s a valve, and I say, “What happens if this valve gets stuck?” — you see? To see if it’s a valve. And they would say to me, “That’s not a valve, Sir, that’s a pyaaa…” — you know? No. It’s a valve. It was a valve! I say, “What happens if this valve gets stuck?” So they say, “Well, then it backs up over here,” and they go through blueprints, up to the second floor, down to the first floor, and these two guys are going up and down, they’re talking, talking, talking, very fast to each other, I don’t know what’s going on, all mixed up — They finally turn to me. “You’re absolutely right, Sir,” they say. Absolute luck! I always have luck like that. I’ve always got crazy luck. “Absolutely right.” Zumwalt, this lieutenant who’d taken me around everywhere, as a kind of, you knew, security guard or something — he just sat there with his mouth hanging loose, you know. After we came out, he said, “Feynman, I know you. I’ve been to see you a lot. But that performance is physically impossible! How did you do that? It’s impossible!” I said, “I did it by luck.” Anyway, that was part of this thing. So I got involved in general safety problem for anywhere else. I had ultimately to go to the plant at Hanford about safety. Wheeler was there and I talked to him about the safety and checked his calculations on safety and so on, but there was no particular thing. I became a kind of a safety expert from Los Alamos on these other plants, although it wasn’t so much, especially at Hanford, that I was from the outside, but to make sure, and then leave. With a like Wheeler it was OK. And the men that I had taught in Tennessee were OK. So gradually there was less of this. Then, with regard to certain safety problems at our own Los Alamos place — because I became kind of an expert on this matter and would give advice — but I didn’t get involved, and didn’t want to get involved, with the safety of the experiments whose purpose it was to make a reaction. It was a different kind of safety. See, safety when the purpose is only to handle materials is a safe matter. Because my whole mental attitude was to be on the low side, you know. It’s a wholly different problem as to how to design experiments. So I did not have anything to do with the safety of the experiments whose purpose it was to get near critical, but only handling in the metallurgy division, handling in the chemistry department, what the trucks should look like, what the safes should look like and the shelves of boron in between the blocks and so on, so that the stuff wouldn’t explode in storing. That kind of stuff. I did do that. (I’m just telling you all the different things.)

http://www.aip.org/history/ohilist/5020_2.html

[AdamSmith]

Weiner:

Have you ever had any difficulty with referees, in terms of papers?

Feynman:

No.

Weiner:

So usually you send it in and it’s accepted as such.

Feynman:

Ever since the first paper, which is the Review of Modern Physics paper on path integrals, in which there was a small objection which I mentioned, there’s never been anything. I mean, I send it in and it gets published, just the way it is.

Weiner:

Who would be the likely referee on your papers on quantum electrodynamics, for example? There wasn’t a very large group that they could turn to.

Feynman:

I don’t know how that works. I myself don’t referee any papers.

Weiner:

What was your attitude on that?

Feynman:

Well, I started to try to look at the papers of other people but, you see, I have a funny thing. To me there’s an infinite amount of work involved. I would have to first understand how he’s thinking about it — not just understand the problem, but what he’s thinking about it. Then I’d have to go and see, is it Ok? Hm. Or what is it? I mean, it’s too much work, darn it. It’s like almost research: checking the ideas, seeing if it really works, and so on. It’s like research, and I can’t do somebody else’s research. I’m not built that way. I can’t think his way. I can’t follow and try to go through all these steps. If I want to worry about the problem, I read the paper to get the problem, and then maybe work it out some other way. But it’s too much work. Now, to read and just check steps — I can’t do it. And then, if a paper comes out that’s bad, that’s not very good, I’d feel very uncomfortable to say that there’s something the matter with it, or that it’s not OK, because maybe I’m not understanding. Maybe it is OK; maybe somebody else will see that it’s all right. I think it’s a lot of nonsense. Finally, I think most of the papers are a lot of nonsense and not worth publishing. And so, altogether it’s a miserable business, and I just say I won’t review any papers in order to simplify it because if I start reviewing some and not others, then it sounds like a criticism. There are a number of other things — I have resisted the outside world on this and a number of other things. For example, I never give commentary on whether a man is loyal or not loyal. You know this kind of investigation. And I got everybody off my back on that by just saying I won’t do it. And I never review papers. And one thing I would like not to have to do, but I can’t avoid, is writing recommendations for students. But after all, sometimes nobody else knows them, and they’re trying to get a job. So I have to do that. But I find it very distasteful. I don’t like to judge other people, or their work, at all. I don’t. I don’t want to judge somebody else’s work.

http://www.aip.org/history/ohilist/5020_4.html

[AdamSmith]

Yes. Right. I don’t know about everybody, but what I think is most impressive is, like when I read about Dirac, for example. I also get a similar feeling about Maxwell. When, say, Dirac got the equation he knows something about nature that nobody else knows. And it is a miracle that it’s possible, by doing experiments over here, to predict what’s going to happen over there. It is not as much a miracle to predict something if you know the laws about it. In other words, it’s enough of a miracle that there are laws at all, but what’s really a miracle is to be able to find the law. It’s another kind of miracle. You see, knowing a law to figure out that such and such is going to do something, and then have nature do it — OK, that’s pretty good. But to look at other aspects and to guess, and to know that there’s a pattern under there, and to tell nature that in this experiment she’s going to do that — no by deduction, strictly speaking, from what’s known but by guessing from what’s known — it seems a wonderful thing to me. And I always wanted to do that. Now, my work in electrodynamics was really using other people’s formulas. My electrodynamics is not unequivalent to the electrodynamics of Pauli, Dirac, and so on, in 1929, with some technical improvements and methods of analysis and so on. It’s fundamentally the same thing. Also, even the diagrams and so on only help people make calculations, and therefore makes predictions, but with a basic theory which is essentially not my own. The work with helium I got a great deal of pleasure out of also, but it still wasn’t exactly that same category, because in the work on helium I had the Schrodinger equation which I thought was going to give the helium. The puzzle here is, how can that equation ever lead to that phenomenon? But that’s still not exactly the same. But here, for a moment, that night, a couple of nights, I have a knowledge of a law and I can make predictions analogous to, but nowhere near as important or as vital and marvelous as, the Dirac equation or Maxwell equation. It’s just a small piece, but at least I have the moment when I’ve a new law, and could predict nature for a while. You remember I said that I was uncomfortable and told my sister I was unable to do work anymore; I’m worn out. And she said, “At least write it up,” and so on and so on. So I was uncomfortable that I wasn’t doing anything. And I suddenly got this thing. And then I finally said: “Well, I’ve done physics now. I’ve finally done some physics now, and I don’t care if I never do anything more.” I don’t mean I didn’t want to do anything more, but I wasn’t going to feel any more that I’ll be uncomfortable and unfulfilled, in the sense that it was an aim that I’d never fulfilled. I felt now that I’d fulfilled my original dream of one day discovering a law which was unknown. It turned out that that law had been guessed by Marshak, and perhaps by Salam and I don’t know who all, earlier than I perhaps. But it doesn’t make any difference. That doesn’t bother me. Maybe it’s bothering Marshak because all the glory comes to Gell-Mann and myself, and that may not be fair for all I know, because I don’t know the situation. I don’t read what the others are writing and doing. And I think it’s possible, although that would have to be studied by an historian, that those other guys got the bad end in this case, and the names that are associated with this thing are not in accordance with priorities. I don’t know. I haven’t the slightest idea. I was told this after I discovered it. So I don’t know, but it’s possible. But that doesn’t have anything to do with it. It’s not the name and the priority. It could have been that they discovered it. As long as I didn’t know they discovered it, for that moment I knew something and I had found a law, and I could make predictions about nature, which is the aim that I had. And the fact that somebody else was already making the predictions, unbeknownst to me, in no way takes the pleasure away, in any way. So that was really a great moment. I would like more moments like that, but I don’t have to ask the gods for everything.

http://www.aip.org/history/ohilist/5020_4.html

[AdamSmith]

NYTimes

: ... The generation coming up behind him, with the advantage of hindsight, still found nothing predictable in the paths of his thinking. If anything he seemed perversely and dangerously bent on disregarding standard methods. "I think if he had not been so quick people would have treated him as a brilliant quasi crank, because he did spend a substantial amount of time going down what later turned out to be dead ends," said Sidney Coleman, a theorist who first knew Feynman at Caltech in the 50's.

"There are lots of people who are too original for their own good, and had Feynman not been as smart as he was, I think he would have been too original for his own good," Coleman continued. "There was always an element of showboating in his character. He was like the guy that climbs Mont Blanc barefoot just to show that it can be done."

Feynman continued to refuse to read the current literature, and he chided graduate students who would begin their work on a problem in the normal way, by checking what had already been done. That way, he told them, they would give up chances to find something original.

"I suspect that Einstein had some of the same character," Coleman said. "I'm sure Dick thought of that as a virtue, as noble. I don't think it's so. I think it's kidding yourself. Those other guys are not all a collection of yo-yos. Sometimes it would be better to take the recent machinery they have built and not try to rebuild it, like reinventing the wheel. Dick could get away with a lot because he was so goddamn smart. He really could climb Mont Blanc barefoot."

Coleman chose not to study with Feynman directly. Watching Feynman work, he said, was like going to the Chinese opera. "When he was doing work he was doing it in a way that was just -- absolutely out of the grasp of understanding. You didn't know where it was going, where it had gone so far, where to push it, what was the next step. With Dick the next step would somehow come out of -- divine revelation."

The characterization below is one of my favorites. We all stand in awe of the magicians!

"There are two kinds of geniuses, the 'ordinary' and the 'magicians,' " wrote the mathematician Mark Kac. "An ordinary genius is a fellow that you and I would be just as good as, if we were only many times better. There is no mystery as to how his mind works. Once we understand what they have done, we feel certain that we, too, could have done it. It is different with the magicians. They are, to use mathematical jargon, in the orthogonal complement of where we are and the working of their minds is for all intents and purposes incomprehensible. Even after we understand what they have done, the process by which they have done it is completely dark. Richard Feynman is a magician of the highest caliber."

http://infoproc.blogspot.com/2013/11/feynman-and-secret-of-magic.html

[RA1]

I definitely stand in awe of "magicians".

Thanks.

Best regards,

RA1

[AdamSmith]

Freeman Dyson recalls:

As soon as I arrived at Cornell, I became aware of Dick as the liveliest personality in our department I had a room in a student dormitory and sometimes around two oclock in the morning I would wake up to the sound of a strange rhythm pulsating over the silent campus. That was Dick playing his bongo drums.

Dick was also a profoundly original scientist. He refused to take anybodys word for anything. This meant that he was forced to rediscover or reinvent for himself almost the whole of physics. It took him five years of concentrated work to reinvent quantum mechanics. He said that he couldnt understand the official version of quantum mechanics that was taught in textbooks, and so he had to begin afresh from the beginning. That was a heroic enterprise. He worked harder during those years than anybody else I ever knew. At the end he had a version of quantum mechanics that he could understand. The calculation that I did for Hans [bethe], using the orthodox theory, took me several months of work and several hundred sheets of paper. Dick could get the same answer, calculating on a blackboard, in half an hour.

So this was the situation which I found at Cornell. Hans was using the old cookbook quantum mechanics that Dick couldnt understand. Dick was using his own private quantum mechanics that nobody else could understand. They were getting the same answers whenever they calculated the same problems. And Dick could calculate a whole lot of things that Hans couldnt. It was obvious to me that Dicks theory must be fundamentally right. I decided that my main job, after I finished the calculation for Hans, must be to understand Dick and explain his ideas in a language that the rest of the world could understand.

https://nige.wordpress.com/2010/08/14/freeman-dyson-on-richard-feynmans-path-integral-quantum-field-theory/

[MsGuy]

They [magicians] are, to use mathematical jargon, in the orthogonal complement of where we are and the working of their minds is for all intents and purposes incomprehensible.

"In the mathematical fields of linear algebra and functional analysis, the orthogonal complement of a subspace W of a vector space V equipped with a bilinear form B is the set W^⊥ of all vectors in V that are orthogonal to every vector in W. Informally, it is called the perp, short for perpendicular complement. It is a subspace of V." Definition from Wiki.

So much clearer with a brief explanation, yes?

[AdamSmith]

Computing by Brain - Los Alamos

Walking around the hastily built wooden barracks that housed the soul of the atomic bomb project in 1943 and 1944, a scientist would see dozens of men laboring over computation. Everyone calculated. The theoretical department was home to some of the world's masters of mental arithmetic, a martial art shortly to go the way of jiujitsu. Any morning might find men such as Bethe, Fermi, and John von Neumann together in a single small room where they would spit out numbers in a rapid-fire calculation of pressure waves. Bethe's deputy, Weisskopf, specialized in a particularly oracular sort of guesswork; his office became known as the Cave of the Hot Winds, producing, on demand, unjustifiably accurate cross sections (shorthand for the characteristic probabilities of particle collisions in various substances and circumstances). The scientists computed everything from the shapes of explosions to the potency of Oppenheimer's cocktails, first' with rough guesses and then, when necessary, with a precision that might take weeks.

...

When he (Feynman) started managing groups of people who handled laborious computation. he developed a reputation for glancing over people's shoulders and stabbing his finger at each error: "That's wrong." His staff would ask why he was putting them to such labor if he already knew the answers. He told them he could spot wrong results even when he had no idea what was right something about the smoothness of the numbers or the relationships between them. Yet unconscious estimating was not really his style. He liked to know what he was doing. He would rummage through his toolbox for an analytical gimmick, the right key or lock pick to slip open a complicated integral. Or he would try various simplifying assumptions: Suppose we treat some quantity as infinitesimal. He would allow an error and then measure the bounds of the error precisely.

...

When Bethe and Feynman went up against each other in games of calculating, they competed with special pleasure. Onlookers were often surprised, and not because the upstart Feynman bested his famous elder. On the contrary, more often the slow-speaking Bethe tended to outcompute Feynman. Early in the project they were working together on a formula that required the square of 48. Feymnan reached across his desk for the Marchant mechanical calculator

Bethe said, "It's twenty-three hundred."

Feynman started to punch the keys anyway. "You want to know exactly?" Bethe said. "It's twenty-three hundred and four. Don't you know how to take squares of numbers near fifty?" He explained the trick. Fifty squared is 2,500 (no thinking needed). For numbers a few more or less than 50, the approximate square is that many hundreds more or less than 2,500. Because 48 is 2 less than 50, 48 squared is 200 less than 2,500-thus 2,300. To make a final tiny correction to the precise answer, just take that difference again-2-and square it. Thus 2,304.

Feymnan had internalized an apparatus for handling far more difficult calculations. But Bethe impressed him with a mastery of mental arithmetic that showed he had built up a huge repertoire of these easy tricks, enough to cover the whole landscape of small numbers. An intricate web of knowledge underlay the techniques. Bethe knew instinctively, as did Feynman, that the difference between two successive squares is always an odd number, the sum of the numbers being squared. That fact, and the fact that 50 is half of 100, gave rise to the squares-near-fifty trick. A few minutes later they needed the cube root of 2 1/2. The mechanical calculators could not handle cube roots directly, but there was a look-up chart to help. Feynman barely had time to open the drawer and reach for the chart before he heard Bethe say, "Thats 1.35. " Like an alcoholic who plants bottles within arm's reach of every chair in the house, Bethe had stored away. a device for anywhere he landed in the realm of numbers. He knew tables of logarithms and he could interpolate with unerring accuracy. Feynman's own mastery of calculating had taken a different path. He knew how to compute series and derive trigonometric functions, and how to visualize the relationships between them. He had mastered mental tricks covering the deeper landscape of algebraic analysis-differentiating and integrating equations of the kind that lurk dragonlike in the last chapters of calculus texts. He was continually put to the test. The theoretical division sometimes seemed like the information desk at a slightly exotic library. The phone would ring and a voice would ask, "What is the sum of the series 1 + (1/2)⁴ + (1/3)⁴ + (1/4)⁴ + . . . ?"

"How accurate do you want it?" Feymnan replied.

"One percent will be fine."

"Okay," Feymnan said. "One point oh eight." He had simply added the first four terms in his head-that was enough for two decimal places. Now the voice asked for an exact answer. "You don't need the exact answer," Feynman said.

"Yeah, but I know it can be done."

So Feynman told him. "All right. It's pi to the fourth over ninety."

He and Bethe both saw their talents as labor-saving devices. It was also a form of jousting. At lunch one day, feeling even more ebullient than usual, he challenged the table to a competition. He bet that he could solve any problem within sixty seconds, to within ten percent accuracy, that could be stated in ten seconds. Ten percent was a broad margin, and choosing a suitable problem was hard. Under pressure, his friends found themselves unable to stump him. The most challenging problem anyone could produce was: Find the tenth binomial coefficient in the expansion of (1 + X)²⁰. Feynman solved that just before the clock ran out. Then Paul Olum spoke up. He had jousted with Feynman before, and this time he was ready. He demanded the tangent of ten to the hundredth. The competition was over. Feynman would essentially have had to divide one by pi and throw out the first one hundred digits of the result-which would mean knowing the one-hundredth decimal digit of pi. Even Feymnan could not produce that on short notice.

Reproduced (scanned) from:

GENIUS. Richard Feynman and modern physics. J Gleik. First Published in Great Britain in 1992 by Little Brown and Company (1992). Chapter 4 (Los Alamos).

http://www.precisioninfo.com/index.php?doc_id=64

[MsGuy]

So much clearer with a brief explanation, yes?

"In mathematics, orthogonality is the relation of two lines at right angles to one another (perpendicularity), and the generalization of this relation into n dimensions; and to a variety of mathematical relations thought of as describing non-overlapping, uncorrelated, or independent objects of some kind." From a different Wiki article.

Now that explanation actually leads to a glimmer of intuitive understanding. Well, at least a little bit.

And with shit like this, every little bit helps.

[AdamSmith]

MUCH better.

[AdamSmith]

PS I had a boss who was originally an electrical engineer and used that expression "orthogonal" all the time in any kind of situation, not just technical, so Pardonnez-Moi for not thinnin' to splain it.

[AdamSmith]

During the bomb project, Oppenheimer wrote this letter to the UC Berkeley physics department chairman recommending they make Feynman a job offer for after the war ended. (Transcript after the image.)

Transcript
 

CONFIDENTIAL

November 4, 1943

Professor R. T. Birge
Chairman, Department of Physics
University of California
Berkeley, California

Dear Professor Birge:

In these war times it is not always easy to think constructively about the peace that is to follow, even in such relatively small things as the welfare of our department. I would like to make one suggestion to you which concerns that, and about which I have myself a very sure and strong conviction.

As you know, we have quite a number of physicists here, and I have run into a few who are young and whose qualities I had not known before. Of these there is one who is in every way so outstanding and so clearly recognized as such, that I think it appropriate to call his name to your attention, with the urgent request that you consider him for a position in the department at the earliest time that that is possible. You may remember the name because he once applied for a fellowship in Berkeley: it is Richard Feynman. He is by all odds the most brilliant young physicist here, and everyone knows this. He is a man of thoroughly engaging character and personality, extremely clear, extremely normal in all respects, and an excellent teacher with a warm feeling for physics in all its aspects. He has the best possible relations both with the theoretical people of whom he is one, and with the experimental people with whom he works in very close harmony.

The reason for telling you about him now is that his excellence is so well known, both at Princeton where he worked before he came here, and to a not inconsiderable number of "big shots" on this project, that he has already been offered a position for the post war period, and will most certainly be offered others. I feel that he would be a great strength for our department, tending to tie together its teaching, its research and its experimental and theoretical aspects. I may give you two quotations from men with whom he has worked. Bethe has said that he would rather lose any two other men than Feynman from this present job, and Wigner said, "He is a second Dirac, only this time human."

Of course, there are several people here whose recommendation you might want; in the first instance Professors Brode and McMillan. I hope you will not mind my calling this matter to your attention, but I feel that if we can follow the suggestion I have made, all of us will be very happy and proud about it in the future. I cannot too strongly emphasize Feynman's remarkable personal qualities which have been generally recognized by officers, scientists and laity in this community.

With every good wish,

Robert Oppenheimer

RO:pd
CC to Dr. Lawrence

[MsGuy]

Wow, I had no idea physicists crushed on each other like that.

 

But Feynman was kinda cute (for a physicist).

[AdamSmith]

He was!