This joint may get raided by the police department, but anyhow, we're going to get started. Our speaker today, as you know, is Richard Phillips feynman Nobel Prize winner in physics and scientist extraordinaire. Very.

The difference between Dick Feynman and other people is that he is more logical and has a greater imagination. This is a rare combination. Most people who are logical don't have much imagination.

As the great Russian physicist Frankel said knowledge progresses by illogical steps. Feynman uses his imagination to probe the scientific frontiers beyond the bounds of logic in much the same manner as mathematicians use complex variables in order to make analytic continuations. At Las Almas at Las Almas robert Oppenheimer rated Dick as his most valuable player.

Besides being an extremely talented theoretical physicist he is a super duper troubleshooter. He can go into an experimental lab and by asking the right questions find the reasons why the experiment doesn't work. It's a great pleasure to have Dick here.

Thanks very much. How do you do? Hello down there. And how to everybody else.

The introduction is quite inappropriate for my talk which is Los Alamos from below. And I mean from below because although, as Mr. Hirschfeld says in my field at the present time I'm a slightly famous man.

At the time, I was not anybody famous at all. I did not even have my degree when I started to work on stuff associated with the Manhattan Project. So I want to describe it from many of the other people who tell you about Los Alamos.

Know something? They're up in some higher echelon of government of the organization or something or worried about some big decisions. I worried about no big decisions. I was always flittering about underneath somewhere.

I wasn't the absolute bottom, as you'll turn out. I did get sort of up a few steps but I wasn't one of the higher people. So I want you to try to put yourself in a different kind of condition than the introduction said.

And just imagine this young graduate student that hasn't got his degree yet is working on his thesis. And I'll start by saying how I got into the project and then what happened to me. That's all.

Just what happened to me during the project. I was working at Princeton in my room one day when Bob Wilson came in. I was working what the hell? It isn't funny yet.

I got lots of better dinner. Bob Wilson came in and said that he had been funded to do a job that was a secret and was not 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. He had a to make ultimately and make a bomb. He had a process for separating the isotopes of uranium which is different than the one that was ultimately used that he'd wanted to try to develop.

And he told me about it and he said, there's a meeting. I said I didn't want to do it. He says, all right.

There's a meeting at 03:00. 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 3 minutes and then I began to pace the floor and to 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 before we did was very much of a fright. So I decided to go to the meeting at 03:00.

By 04:00, I already had a desk in a room them and was trying to calculate whether this particular method was limited by the total amount of current that you can get in an ion beam and so on. I won't go into the details, but I had a desk and I had pavement. I'm working as hard as I could and as fast as I can.

Whereas the fellows were building the apparatus to do the experiments right there the other fellows who were joined. And it was like those moving pictures that you see where you see a piece of equipment. Go, every time I'd look up, the thing was getting bigger.

And what was happening, of course is that all the boys had decided to work on this and to stop their research in science. All the science stopped during the war except the little bit that was done in Los Alamo. It was not much science.

It was a lot of engineering. And they were robbing their equipment from their research. And all the equipment of different research was being put together to make the new apparatus to do the experiments to try to separate the isotopes of uranium.

And I stopped my work also for the same reason. It is true that I did take a six week vacation off after a while from that job and finished writing my thesis. So I did get my degree just before I got to Los Alamos.

So I wasn't quite as far down as I led you to believe. One of the first experiences that was very interesting to me in this project at Princeton was to meet great men. I had never met very many great men before but there was a committee, evaluation committee that had to decide which way we're going and to try to help us along to ultimately decide which way we're going to separate the uranium.

This evaluation committee had men like Tolman and Smyth and Yuri and Robbie and Oppenheimer and so forth on it. And it was Compton, for example. One of the things that was a terrible shock to I'd sit there because I understood the theory of this process that we're doing.

And so they asked me questions and I'd be there and then we'd discuss it. And then they'd start to discuss something and one man would make a point and then Compton would explain a different point of view and he would be perfectly right and it was the right idea. And he said it should be this way.

Another guy would say, well, maybe there's this possibility we have to consider against it another possibility we have to consider. I'm jumping. They should repeat compton's priest should say it again.

He should say it again because everybody's disagreeing with all the way around the table. So finally at the end says 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. And 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 and remembering what the other fellow said, having paid attention.

And so at the end, the decision is made as to which idea was the best of summary it all together without having to say it three times, you see? So that was a shock. And these were very great men indeed. This project was ultimately decided not to be the way that they were going to separate uranium.

And we were told then that we were going to stop and that there would be, starting in Los Alamos in New Mexico the project which would actually make the bomb and that we would all go out there to make it. There would be experiments that we would have to do theoretical work that we'd have to do. I was in the theoretical work.

All the rest of the fellows were in experimental work. The question was what to do? Because we had this heatless of time where we'd just been told to turn off. But Los Alamos wasn't ready yet.

So Bob Wilson tried to make use of his time by saying to send me to Chicago to find out all that we could find out about the bomb and the problems so that we could start to build in our laboratories equipment counters of various kinds and so on. That would be useful when we got to Los Alamo. 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 have them tell me about a problem to the extent that I knew enough to that I could actually sit down and start working on the problem. And as soon as I got that far, go to another guy and ask for a problem. And that way I would understand the details of everything.

It was a very good idea. My conscience bothered me a little bit, but it turned out accidentally. I was very lucky in one of the guys explaining the problem.

I says, Why don't you do it that way? And in a half an hour he had it solved and they'd been working on it for three months. So I did something. So I came back from Chicago and I described this situation how much energy was released, what the bomb was going to be like and so forth to the fellas.

I remember a friend of mine who worked with me, Paul Olum, mathematician, came up to me after. He said when they make a moving picture about this they'll have the guy coming back from Chicago telling the Princeton men all about the bomb. And he'll be dressed in a suit and carry a briefcase and sign and you're in dirty shirt sleeves and just telling us all about it.

But it's a very serious thing anyway. And so he appreciated the difference between the real world and that in the movies. Well, there still seemed to be a delay.

And Wilson went to Los Alamos to find out what was holding things up and how they were progressing. And when he got there, he found that the construction company was working very hard and had finished the theater and a few buildings because they understood how but they hadn't gotten instructions clear on how to build the laboratories how many pipes for gas, how much for water. So he simply stood around and decided how much water, how much gas, and so on and told him to start building the laboratories.

And he came back to us. We were all ready to go, you see. And Oppenheimer was having some difficulties in discussing some problems with groves and we were getting impatient.

So what, as far as I understand it from the position I was in wilson called Manly in Chicago and they all got together and they decided we'd go out there anyway when it wasn't ready. So we all went out to Los Alamos before it was ready. We were recruited, by the way, by Oppenheimer and other people.

And he was very patient with everybody. 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.

And it was the first time I met him in such a personal way. And he was such a wonderful man. We were told, among other things, to be careful and not to buy our train ticket in Princeton because Princeton was a very small train station.

And if everybody bought train ticket to Albuquerque, New Mexico, in Princeton, there'd be some suspicion that something was up. And so everybody bought that ticket at somewhere else. In fact, me, because I figured if everybody bought that ticket somewhere else so when I went to the train station and I said, I want to go to Albuquerque, New Mexico he says, oh.

He says, So all the stuff is for you. We've been shipping out crates full of counters for weeks and expecting they didn't notice that the address was Albuquerque. So at least I explained why it was that we were shipping out crates.

I was going out to Albuquerque. Well, when we arrived, we were ahead of time and the houses for the dormitories and things like that were not ready. In fact, the laboratories weren't quite ready.

We were pushing them. We were driving them by coming down ahead of time. They went crazy at the other end and they rented ranch houses all around in the neighborhood.

And we stayed at first at 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's a great cliffs. You've probably seen the pictures. I won't go into it much detail.

This thing was high on a mesa and you'd come up from below and see these great cliffs. And we were very surprised. And the most impressive thing to me was that as I was going up, I said maybe there were Indians even living here.

The guy who was driving the car said, Just stop. He stops the car, walks around the corner and there are Indian caves that you can inspect. So it was really very exciting in that respect.

When I got up to the site the first time I saw at the gate of the you see, there was a technical area where we're supposed to do the work with a fence supposed to have a fence around it, ultimately. But because they were still building, it was open. Then there was supposed to be a town and then a big fence further out around the town they were still building.

And my friend Paul Olum, who was my assistant was standing with a clipboard checking the trucks coming in and out and telling him which way to go and to deliver the materials in different places. When I went into the laboratory I would meet men that I'd heard of by seeing their papers in their physical review and so on. I never met him before.

This is John Williams, they said. The guy comes standing up from a desk which is covered with blueprints and sleeves all rolled up and he's standing by some windows at one of the buildings ordering trucks and things going in different directions to build the things. In other words, we took over the construction company and finished the job.

The physicists, in other words, at the beginning, the experimental physicists particularly had nothing to do until their buildings were ready and apparatus is ready. So they just built the buildings or assisted in building the buildings. The theoretical physicists are now that was decided that they wouldn't live in the ranch houses but they would live up at the site because they could start working right away.

So we started working immediately and that meant we would each get in some rooms, there were no blackboard except for one, a rolled blackboard on wheels that you'd roll around. And we'd roll it around. And Cerber 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.

And I didn't know very much about it. I'd been doing other kinds of things, and so I had to do an awful lot of work every day. I'd study and read and study and read.

And it was a very hectic time. I had some luck. All the big shots by some kind of accident, everybody but Hans Beta happened to have left at the same time.

Like Vyskov had to go back to fix something at MIT. And Teller was away just at a certain moment. And what Beta needs is somebody to talk to, to push his ideas against.

So he came into this little squirt in an office, and he starts to explain this idea. And I says, no, no, you're crazy. It'll go like this.

And he says, Just a moment. And he explains that he's not crazy, that I'm crazy. And we keep on going like that.

But I turned out that, although, 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 the dopeiest things like, no, no, that's wrong, or you're crazy. But it turned out that's exactly what he needed.

So I got a notch up on account of that. And so when I ended up as a group leader with four guys under me, which is underneath Beta, there were several groups, but I wasn't quite as far below as the title might indicate. But I wasn't anywhere up anywhere.

I had a lot of interesting experiences with Beta. The first day when he came in, we had a adding machine at Marshant that you work with your hands. And so he says let's see.

He says the formula where he'd been working out, he says, involves a pressure squared. The pressure is 48, the square of 48. 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 23 four. And so it came out 23 four.

How do you do that? He says, don't you know how to take squares and numbers near 50 if it's near 50, if it's say, three below, then it's three below 25. Like 47 squared is 22. And how much is left over is the square of what's residual.

For instance, three lost. So you get 922 nine for 47 squared. Very nice.

Okay. So we keep on he was very good in arithmetic, so we kept on going. And a few moments later we had to take the cube root of two and a half.

Now, to do cube roots. There was a little chart that you take and you have some trial numbers that you try on the adding machine the Marshan Company had given. So I opened this takes him a little longer, you see.

I open the drawer. I take out the chart. He says, 1.35.

So I figured there's some way to take cube roots numbers near two and a half. But it turns out, no. How do you do that? He says, well, he says, you see, the logarithm of two and a half is so and so.

You divide by three to get the cube root of so and so. Now, the log of 1.3 is this.

The log of 1.4 is it? I interpolate in between. I couldn't have divided anything by three, much less 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 rush to the answer, he and I, and I would win. After several years, I began to be able to do it.

Get in there once, maybe one out of four because you'd notice something funny about a number. Like if you have to multiply 174 by 140, for example, you notice that's like 173 by 141 which is like the square root of three times the square root of two which is the square root of six, which is 245. But you have to notice the numbers.

Each guy would notice a different way around. We had lots of fun. Well, when I was first there, as I said, we didn't have the dormitories and the theoretical physicist had to stay up there.

And the first place they put us was in the old school buildings from the boys school that had been there previously. The first place I lived in was a thing called a mechanics lodge. It were all jammed in there in bunk beds and so on.

And it turned out it wasn't organized very well. And Bob Christie and his wife had to go to the bathroom in the morning through our bedroom. So that was very uncomfortable.

The next place we moved to was a thing called the big House which had a big patio all the way around the outside on the second floor where all beds had been stuck next to each other all along long. And then downstairs there was a big chart that told you what your bed number was and which bathroom you changed the clothes in. So under my name it said, Bathroom C.

No bed number. As a result of this, I was rather annoyed. By this time.

I was getting annoyed. At last, the dormitory is built. I'd go down to the dormitory place to get the rooms assigned and they say, you pick your room.

Now, I tried to pick one. You know what I did? I looked and see where the girl's dormitory was and I picked one that you could look out across later I discovered a big tree was growing right in front of me. But anyway, I picked this room and they told me that temporarily there would be two people in a room, but that would only be temporary, that the rooms were two rooms which would share a bathroom, but it would be double deck and bunk in there.

And I didn't want two people in the room. So when I first got there, the first night, nobody else was there. Now.

My wife was sick with TB. In Santa Fe? In Albuquerque. So I had some boxes of stuff of hers.

So I opened the box and I took out a little nightgown. I opened the top bed. I threw the nightgown carelessly on the top bed.

I took out the slippers. I threw some powder on the floor in the bathroom. I just made it look like somebody else is there.

Okay? So that the other bed is occupied. Nobody's going to sleep there. Okay, so what happened because it's the men's dormitory? Well, I came home that night and my pajamas are folded nicely and put under the pillow at the bottom and the slippers put nicely at the bottom of the bed.

And the lady's pajama is nicely folded. The bed has been all fixed up and made and it's put under the pillow and the slippers are put down nicely and the powder is cleaned from the bathroom and nobody is sleeping up there. I still have the room to myself.

So next night, same thing. When I wake up, I smuggle up the bed at the top properly. I throw the nightgown and powder up in the bathroom and so on.

And I went on like this for four nights until it settled down. Everybody was settled and there was no more danger that they would put a second person in the room. And each night, perpetually, each morning, everything was set very neatly.

Everything was all right, even though it was a men's dormitory. So that's what happened there. In that situation.

I got involved in politics a little bit because there was a thing called the town council. And apparently there were certain things the army people would decide how the town was supposed to be run with some assistance from some governing board up there that I never knew anything about, from the civilians or something. But there were all kinds of excitement, like there isn't any political thing.

And so there were factions the Housewife faction, the mechanics faction, the technical people faction, so on. Well, the bachelors and bachelor girls, the people who lived in the dormitories felt they had to have a faction because a new rule had been promulgated. No women in the men's dorms.

Well, this is absolutely ridiculous. All grown people, of course, ha. And so what kind of nonsense and so forth.

So we had to have political action and we discarded and we debated and all this stuff, you know, how it is. And so I was elected to represent the dormitory people, you see, in a town council. So I was in the town council for a while after I was in the town council, about a year or so, a year and a half.

I was talking once to Hans Bada about something, and he was up in the governing council during all this time, and I told him this story I forgot about that. I did this trick one time with my wife's stuff on the upper bed. And he started to laugh.

He says, Ah, that's how you got on the town council. Because it turned out that what happened was this. There was a report, a very serious report.

The poor woman was shaking. The woman who cleans the rooms in the dormitory had just opened, and all of a sudden there's trouble. Somebody's sleeping with one of the guys.

Sheikh doesn't know what to do. So Char woman reports to the chief. Char woman, the chief.

Char woman reports to the lieutenant. The lieutenant reports to the major, goes all the way up. It goes all the way up to the general, to the governing board.

What are they going to do? What are they going to do? Are you still going to think about it? So in the meantime, what? In the meantime, instructions go down, bound through the captains, down through the major, through the lieutenant, through the chief, through the char woman to just put things back the way they are, clean them up and see what happens. Okay? Next day report, same thing. Meantime, for four days, they worried up there what they're going to do.

So they finally promulgated a rule no women in the men's dormitories. And that caused such a stink down there, you see, that they had to have all the politics, and they elected somebody to represent the now, I'd like to tell you about the censorship that we had. They decided to do something utterly illegal, which is to censor mail of people inside the United States, in the continental United States, which I 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 our envelopes that we would send the letters out with. We would accept it be all right if they would open letters coming into us that was voluntarily accepted by us.

We would leave the letters open. They would seal them if they were okay, if they weren't okay, in their opinion. In other words, they said something that we shouldn't send out.

They would send the letter back to us with a note that said it was a violation of such and such a paragraph of our understanding and so on. So very delicately, amongst all these liberal minded scientific guide agreeing to such a proposition, we finally got the censorship set up with many rules about that. 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.

So it was all set up, and they said that we'd notify us of any difficulty. So the day starts, the first day for censorship. Telephone.

Bring me what? Please come down. I come down. What's this? It's a letter from my father.

But what is it? There's lined paper, and there's these lines going on with dots four dots under, one dot above, two dots under, one dot above, two gray under. What's that? I said it's a code. They said, yeah, what's the 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, I don't know. Then they said, what's this? It was a letter from my wife. It says T-J-X-Y-W-Z TW one X three.

What's this? I said another code. What's the key to it? I don't know. They said, you mean you're receiving codes and you don't know the key? I said precisely.

I said, 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 not going to tell me what the key is, and they're sending them in. 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 ask them, please, to send the key in with the code. I said, I don't want to see the key. They says, all right, we'll take the key out.

So we had that arrangement. Okay. All right.

Next day, I get a letter from my wife which says, it's very difficult writing because I feel that the is looking over my shoulder. And in the spot there's, nicely eradicated a splotch with an Ink Eradicator. So I went down to the bureau.

I said, you're not supposed to touch the incoming mail. If you don't like it, you can tell me, but you're not supposed to do anything to it. You should look at it, but you're not supposed to take anything out.

They said, don't be ridiculous. That's not the way Census worked with Ink Eradicator. They cut things out with a scissor.

Okay? So I wrote a letter back to my wife, did you use Ink Eradicator in your letter? She writes back, no, I didn't use Ink Eradicator. My letter must have been the, and there's a hole cut out with it. So I went back I went back to the guy in charge, the, the major who was supposed to be in charge of all this and complained.

This went on for several days. I felt I was sort of the representative to get the thing straightened out. He.

Tried to explain to me that these people who were the censors had been taught how to do it and they didn't understand this new way that we had to be so delicate about. So I was trying to be the front to try to the one with the most experience. I was writing to my wife back and forth every day anyway.

So he said, what's the matter? He don't you think I have goodwill? I says, yes, you have perfectly goodwill, but I don't think you have power. Because he had done three or four days. He said, oh, we'll see about that.

He grabs the telephone. Everything was straightened out, so no more was the letter cut. However, there was a number of difficulties that were us.

For example, one day I got a letter from my wife and the note from the census 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 says, well, where's all the stuff? I said what stuff? She says, Lithog, glycerin, hot dogs, laundry.

I says, wait a minute. That was a list. She says, yes, that was a code.

I said, they thought it was a code lithoglycerin list. Then one day I'm jiggling around. In the first few weeks all this went on.

It was a few weeks before we ever got it straightened out. But I'm piddling around with the adding machine, a computing machine. I noticed something.

So I've been writing every day. I had a lot of things I write. It's very peculiar.

Notice what happens if you take one divided by 273. You get zero zero 411-522-6337 is quite cute. And then it goes a little cockeye when the carrying occurs only for about three numbers.

And then you can see how the 1010 13 is really equivalent to 1114 one one five again and keeps on going. And I explained that how nicely it repeated itself 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 17 B. I look at paragraph 17 B, says, letters are to be written only in English, Russian, Spanish, Portuguese, Latin, god knows what I can't 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 sensor a little note included in my letter which said of course, this cannot be a code because there's no more. If you actually do divide one into two, you do in fact get and I wrote the whole thing.

And therefore there's no more information in the number 110-0411 than there is in the number 273, which is hardly any information and so forth. I therefore asked for permission to write my letters in Arabic. Numerals.

I like 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, at one time my wife kept insisting on mentioning the fact that she feels uncomfortable writing feeling that the sensor is looking over. And there was 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, sir. My wife mentioned censorship.

So finally they send me a note and say, please inform your wife not to mention censorship in our letters. So I take my letter and I start. I have been instructed to inform you not to mention censorship in your letters.

Boom, boom. Comes right back. So I write, I have been instructed to inform her 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 citizenship? You're keeping something from me. It's very interesting. 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. They're worried about the mail being intercepted on the way from Albuquerque and that they would find out that there was censorship if they looked in the mail and would she please act much more normal? And so I went down the next time to Albuquerque and I talked to her and I said, now, looks, let's not mention censorship. But we had had so much trouble that we had at last worked out a code, something illegal.

We had a code. 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'd sit there all day long because she was ill and she'd think of things to do.

The last thing that she did was to send me because she found perfectly legitimately an advertisement that said send your boyfriend a letter on a jigsaw puzzle. Here are the blanks. We sell you the blank.

You write the letter on, take it all apart and put a little sack in mail. So I received that one with a note saying we do not have time to play games. Please instruct please instruct your wife to confine herself to ordinary letters.

Well, we're ready with the one more dot. But they got ready just in time. But the thing that we had ready for the next one was the letter would start.

I hope you remember to open this letter carefully because I have included the Pepto Bismol for your stomach. As we arrange would be a letter full of powder in their office. We expect they'd open it quickly.

The powder would go all over the floor. They'd get all upset because it's not supposed to disturb anything. You see, have to gather this Pepto Bismal, but we didn't have to use that one.

Okay? As a result of all these experiences with the sensor, 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 finally out of all this by making bets one day on the outside fence.

The outside fence. I had discovered that workmen who lived still further out and wanted to come in were too lazy to go around through the gate and so they had cut themselves a hole some distance along. And so I went out the gate, went over to the hole and came in, went out again and so on until the guy, the sergeant at the gate begins to wonder what's happening.

This guy's always going out and never coming in. And of course, his natural reaction was to call a lieutenant and try to put me in jail for doing this. I explained there was a hole, so I was always trying to straighten people out, point out there was a hole.

And so I made a bet with somebody that I could tell where the hole in the fence was in a mail, mail it out. And sure enough, I did. And the way I did it, I said, you should see the way they administer to this place.

See, that's what we were allowed to say. There's a hole in the fence 71ft away from such and such a place that's this size and that size you can walk through. Now what can they do? They can't say to me that there's 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 they got that one through. I also got through a letter which told about how one of the boys who worked in one of my groups 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 or something.

I think it's supposed to be a communist. His name was Kamini. He's a famous man.

Well, there was also some other things I was always trying to straighten out, like point out the holes in the fence and so forth. But always these things where I was always doing these pointings out in a nondirect manner. And one of the things I wanted to point out was this, that at the very beginning we had terribly important secrets.

We'd worked out lots of stuff about uranium, how it worked. And all this stuff was in documents that were in filing cabinets that were made out of wood that had on them little ordinary common padlocks and various things made by the shop like a rod that would go down and then a padlock to hold it. But so was less the padlock furthermore, you could get the stuff out even without opening the padlock out of these wooden cabinets.

You just tilt it over backwards and the bottom drawer has a little rod that's supposed to hold and there's a hole in the wood underneath. You can pull the papers out from below. So I used to pick the locks all the time and point out that it was very easy to do.

And every time we had a meeting of everybody together I'd get up and I'd say that we have important secrets and we need better locks. And so one day, Teller got up at the meeting I got up at and he says to me, well, I don't keep my most important secrets in my filing cabinet. I keep them in my desk drawer.

Isn't that better? I said, I don't know. I haven't seen your desk drawer. Well, he's sitting near the front of the meeting, and I'm sitting further back.

So the meeting continues, and I sneak out of the meeting and I go down to see his desk drawer. Okay, I don't even have to pick the lock on the desk drawer. It turns out if you put your hand in the back underneath you can pull out a paper like those toilet paper dispensers.

You pull out one, it pulls another, pulls another. I emptied the whole damn drawer, took everything out and put it away to one side and then went up on the higher floor and came back. And the meeting is just ending and everybody's coming out.

And I joined the crew like this, you see, walking along with it and run up to catch up with Teller and says, oh, by the way, let me see your desk drawer, you see. So he says, certainly. He says.

So we walk into his office, and he shows me the desk, and I look at. I says, that looks pretty good to me. That's pretty safe.

It looks to me like it's pretty safe. I said, let's see what you have in there. So he says, I'll be very glad to show it to you.

He says, putting the key opens. It looks, and he says, if you hadn't already seen it yourself the trouble with playing a trick on a highly intelligent man like Mr. Teller is the time that it takes him to figure out from the moment that he sees that there's something wrong till he understands exactly what happened.

He's too damn small to give you any pleasure. Well, I had a lot of other fun with the safes but it has nothing to do with Los Alamos. So I won't discuss it further.

I want to tell about some of the special problems that I had that are rather interesting. One of them had to do with the safety of the plant at Oak Ridge. Los Alamos is going to make the bomb.

But at Oak Ridge they're trying to separate the isotopes of uranium uranium 238 and uranium 236, the latter, which is the 235, which is the explosive one. All right? So they were just beginning to get infinitesimal amounts from an experimental thing of the 235. And at the same time they were practicing, there was a big plant that was going to be, we're going to have VAT to this stuff, and they're going to chemicals and take the purified stuff and then repurify and get it ready for the next stage.

They have to purify in several stages. So they were practicing the chemistry on the one hand, and they were just getting a little bit from one of the pieces of apparatus experimentally, on the other hand, and they were trying to learn how to assay it to determine how much uranium 235 there is in it. And we would send instructions.

And they never got it right. So finally, Segre said that the only possible way to get it right is to go down there to see what they're doing, to understand why the assay is wrong. The army people said, no, it is our policy to keep all the information los Anomos in one place, and that the people oakwood you would not know anything about what it was used for.

They just knew what they were trying to do. I mean, the higher people knew they were separating uranium, but they didn't know how powerful the bomb was or exactly how it worked or anything. And the people underneath didn't know at all what they were doing.

The army wanted to keep it that way. There was no information going back and forth, but Sagrey finally insisted on it, that it was important. They could never get the assays right.

The whole thing would go up in smoke. So Sagrey went down to see what they were doing, and as he was walking through, he saw them wheeling a tank carboy of water, green water. The green water is uranium nitrate.

He says, you're going to handle it like that when it's purified, too? They said, sure, why not? Well, won't it explode? He says explode. How are they going to and so the army said, you see, we shouldn't have let any information go across. Well, it turned out that the army had realized how much stuff we needed to make a bomb, 20 kg or whatever it was.

And they realized that that much material purified would never be in the plant, so there was no danger. But they did not know that the neutrons are enormously more effective when they're slowed down in water. And so in water, it takes less than a 10th, no, 20 100th, very much less material.

You can make a reaction which makes radioactivity, doesn't make a big explosion, but makes radioactivity, kills people around and so on. So it was very dangerous, and they had not paid any attention to safety at all. So a telegram goes from Oppenheimer to Saray.

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

And so two groups started working on it. Christie's group worked on water solutions and I worked on dry powder in boxes. My group and we calculated about how much material and Christie was going to go down and tell them all at Oak Ridge what the situation was.

The whole thing was broken down. We have to go down and tell them now. And so I happily give all my numbers to Christie and say, you have all this stuff.