to invent ways of doing it better.
They improved the scheme. They worked at night. They didn't need supervising
in the night; they didn't need anything. They understood everything; they
invented several of the programs that we used.
So my boys really came through, and all that had to be done was to tell
them what it was. As a result, although it took them nine months to do three
problems before, we did nine problems in three months, which is nearly ten
times as fast.
But one of the secret ways we did our problems was this. The problems
consisted of a bunch of cards that had to go through a cycle. First add,
then multiply -- and so it went through the cycle of machines in this room,
slowly, as it went around and around. So we figured a way to put a different
colored set of cards through a cycle too, but out of phase. We'd do two or
three problems at a time.
But this got us into another problem. Near the end of the war, for
instance, just before we had to make a test in Albuquerque, the question
was: How much energy would be released? We had been calculating the release
from various designs, but we hadn't computed for the specific design that
was ultimately used. So Bob Christy came down and said, "We would like the
results for how this thing is going to work in one month" -- or some very
short time, like three weeks.
I said, "It's impossible."
He said, "Look, you're putting out nearly two problems a month. It
takes only two weeks per problem, or three weeks per problem."
I said, "I know. It really takes much longer to do the problem, but
we're doing them in parallel. As they go through, it takes a long time and
there's no way to make it go around faster."
He went out, and I began to think. Is there a way to make it go around
faster? What if we did nothing else on the machine, so nothing else was
interfering? I put a challenge to the boys on the blackboard -- CAN WE DO
IT? They all start yelling, "Yes, we'll work double shifts, we'll work
overtime," all this kind of thing. "We'll try it. We'll try it!"
And so the rule was: All other problems out. Only one problem and just
concentrate on this one. So they started to work.
My wife, Arlene, was ill with tuberculosis -- very ill indeed. It
looked as if something might happen at any minute, so I arranged ahead of
time with a friend of mine in the dormitory to borrow his car in an
emergency so I could get to Albuquerque quickly. His name was Klaus Fuchs.
He was the spy, and he used his automobile to take the atomic secrets away
from Los Alamos down to Santa Fe. But nobody knew that.
The emergency arrived. I borrowed Fuchs's car and picked up a couple of
hitchhikers, in case something happened with the car on the way to
Albuquerque. Sure enough, just as we were driving into Santa Fe, we got a
flat tire. The two guys helped me change the tire, and just as we were
leaving Santa Fe, another tire went flat. We pushed the car into a nearby
gas station.
The gas station guy was repairing somebody else's car, and it was going
to take a while before he could help us. I didn't even think to say
anything, but the two hitchhikers went over to the gas station man and told
him the situation. Soon we had a new tire (but no spare -- tires were hard
to get during the war).
About thirty miles outside Albuquerque a third tire went flat, so I
left the car on the road and we hitchhiked the rest of the way. I phoned a
garage to go out and get the car while I went to the hospital to see my
wife.
Arlene died a few hours after I got there. A nurse came in to fill out
the death certificate, and went out again. I spent a little more time with
my wife. Then I looked at the clock I had given her seven years before, when
she had first become sick with tuberculosis. It was something which in those
days was very nice: a digital clock whose numbers would change by turning
around mechanically. The clock was very delicate and often stopped for one
reason or another -- I had to repair it from time to time -- but I kept it
going for all those years. Now, it had stopped once more -- at 9:22, the
time on the death certificate!
I remembered the time I was in my fraternity house at MIT when the idea
came into my head completely out of the blue that my grandmother was dead.
Right after that there was a telephone call, just like that. It was for Pete
Bernays -- my grandmother wasn't dead. So I remembered that, in case
somebody told me a story that ended the other way. I figured that such
things can sometimes happen by luck -- after all, my grandmother was very
old -- although people might think they happened by some sort of
supernatural phenomenon.
Arlene had kept this clock by her bedside all the time she was sick,
and now it stopped the moment she died. I can understand how a person who
half believes in the possibility of such things, and who hasn't got a
doubting mind -- especially in a circumstance like that -- doesn't
immediately try to figure out what happened, but instead explains that no
one touched the clock, and there was no possibility of explanation by normal
phenomena. The clock simply stopped. It would become a dramatic example of
these fantastic phenomena.
I saw that the light in the room was low, and then I remembered that
the nurse had picked up the clock and turned it toward the light to see the
face better. That could easily have stopped it.
I went for a walk outside. Maybe I was fooling myself, but I was
surprised how I didn't feel what I thought people would expect to feel under
the circumstances. I wasn't delighted, but I didn't feel terribly upset,
perhaps because I had known for seven years that something like this was
going to happen.
I didn't know how I was going to face all my friends up at Los Alamos.
I didn't want people with long faces talking to me about it. When I got back
(yet another tire went flat on the way), they asked me what happened.
"She's dead. And how's the program going?"
They caught on right away that I didn't want to moon over it.
(I had obviously done something to myself psychologically: Reality was
so important -- I had to understand what really happened to Arlene,
physiologically -- that I didn't cry until a number of months later, when I
was in Oak Ridge. I was walking past a department store with dresses in the
window, and I thought Arlene would like one of them. That was too much for
me.)
When I went back to work on the calculation program, I found it in a
mess: There were white cards, there were blue cards, there were yellow
cards, and I started to say, "You're not supposed to do more than one
problem -- only one problem!" They said, "Get out, get out, get out. Wait --
and we'll explain everything."
So I waited, and what happened was this. As the cards went through,
sometimes the machine made a mistake, or they put a wrong number in. What we
used to have to do when that happened was to go back and do it over again.
But they noticed that a mistake made at some point in one cycle only affects
the nearby numbers, the next cycle affects the nearby numbers, and so on. It
works its way through the pack of cards. If you have fifty cards and you
make a mistake at card number thirty-nine, it affects thirty-seven,
thirty-eight, and thirty-nine. The next, card thirty-six, thirty-seven,
thirty-eight, thirty-nine, and forty. The next time it spreads like a
disease.
So they found an error back a way, and they got an idea. They would
only compute a small deck of ten cards around the error. And because ten
cards could be put through the machine faster than the deck of fifty cards,
they would go rapidly through with this other deck while they continued with
the fifty cards with the disease spreading. But the other thing was
computing faster, and they would seal it all up and correct it. Very clever.
That was the way those guys worked to get speed. There was no other
way. If they had to stop to try to fix it, we'd have lost time. We couldn't
have got it. That was what they were doing.
Of course, you know what happened while they were doing that. They
found an error in the blue deck. And so they had a yellow deck with a little
fewer cards; it was going around faster than the blue deck. Just when they
are going crazy -- because after they get this straightened out, they have
to fix the white deck -- the boss comes walking in.
"Leave us alone," they say. I left them alone and everything came out.
We solved the problem in time and that's the way it was.
I was an underling at the beginning. Later I became a group leader. And
I met some very great men. It is one of the great experiences of my life to
have met all these wonderful physicists.
There was, of course, Enrico Fermi. He came down once from Chicago, to
consult a little bit, to help us if we had some problems. We had a meeting
with him, and I had been doing some calculations and gotten some results.
The calculations were so elaborate -- it was very difficult. Now, usually I
was the expert at this; I could always tell you what the answer was going to
look like, or when I got it I could explain why. But this thing was so
complicated I couldn't explain why it was like that.
So I told Fermi I was doing this problem, and I started to describe the
results. He said, "Wait, before you tell me the result, let me think. It's
going to come out like this (he was right), and it's going to come out like
this because of so and so. And there's a perfectly obvious explanation for
this --"
He was doing what I was supposed to be good at, ten times better. That
was quite a lesson to me.
Then there was John von Neumann, the great mathematician. We used to go
for walks on Sunday. We'd walk in the canyons, often with Bethe and Bob
Bacher. It was a great pleasure. And von Neumann gave me an interesting
idea: that you don't have to be responsible for the world that you're in. So
I have developed a very powerful sense of social irresponsibility as a
result of von Neumann's advice. It's made me a very happy man ever since.
But it was von Neumann who put the seed in that grew into my active
irresponsibility!
I also met Niels Bohr. His name was Nicholas Baker in those days, and
he came to Los Alamos with Jim Baker, his son, whose name is really Aage
Bohr. They came from Denmark, and they were very famous physicists, as you
know. Even to the big shot guys, Bohr was a great god.
We were at a meeting once, the first time he came, and everybody wanted
to see the great Bohr. So there were a lot of people there, and we were
discussing the problems of the bomb. I was back in a corner somewhere. He
came and went, and all I could see of him was from between people's heads.
In the morning of the day he's due to come next time, I get a telephone
call.
"Hello -- Feynman?"
"Yes."
"This is Jim Baker." It's his son. "My father and I would like to speak
to you."
"Me? I'm Feynman, I'm just a --"
"That's right. Is eight o'clock OK?"
So, at eight o'clock in the morning, before anybody's awake, I go down
to the place. We go into an office in the technical area and he says, "We
have been thinking how we could make the bomb more efficient and we think of
the following idea."
I say, "No, it's not going to work. It's not efficient... 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."
This went on for about two hours, going back and forth over lots of
ideas, back and forth, arguing. The great Niels kept lighting his pipe; it
always went out. And he talked in a way that was un-understandable --
mumble, mumble, hard to understand. His son I could understand better.
"Well," he said finally, lighting his pipe, "I guess we can call in the
big shots now." So then they called all the other guys and had a discussion
with them.
Then the son told me what happened. The last time he was there, Bohr
said to his son, "Remember the name of that little fellow in the back over
there? He's the only guy who's not afraid of me, and will say when I've got
a crazy idea. So next time when we want to discuss ideas, we're not going to
be able to do it with these guys who say everything is yes, yes, Dr. Bohr.
Get that guy and we'll talk with him first."
I was always dumb in that way. I never knew who I was talking to. I was
always worried about the physics. If the idea looked lousy, I said it looked
lousy. If it looked good, I said it looked good. Simple proposition.
I've always lived that way. It's nice, it's pleasant -- if you can do
it. I'm lucky in my life that I can do this.
After we'd made the calculations, the next thing that happened, of
course, was the test. I was actually at home on a short vacation at that
time, after my wife died, and so I got a message that said, "The baby is
expected on such and such a day."
I flew back, and I arrived just when the buses were leaving, so I went
straight out to the site and we waited out there, twenty miles away. We had
a radio, and they were supposed to tell us when the thing was going to go
off and so forth, but the radio wouldn't work, so we never knew what was
happening. But just a few minutes before it was supposed to go off the radio
started to work, and they told us there was twenty seconds or something to
go, for people who were far away like we were. Others were closer, six miles
away.
They gave out dark glasses that you could watch it with. Dark glasses!
Twenty miles away, you couldn't see a damn thing through dark glasses. So I
figured the only thing that could really hurt your eyes (bright light can
never hurt your eyes) is ultraviolet light. I got behind a truck windshield,
because the ultraviolet can't go through glass, so that would be safe, and
so I could see the damn thing.
Time comes, and this tremendous flash out there is so bright that I
duck, and I see this purple splotch on the floor of the truck. I said,
"That's not it. That's an after-image." So I look back up, and I see this
white light changing into yellow and then into orange. Clouds form and
disappear again -- from the compression and expansion of the shock wave.
Finally, a big ball of orange, the center that was so bright, becomes a
ball of orange that starts to rise and billow a little bit and get a little
black around the edges, and then you see it's a big ball of smoke with
flashes on the inside, with the heat of the fire going outwards.
All this took about one minute. It was a series from bright to dark,
and I had seen it. I am about the only guy who actually looked at the damn
thing -- the first Trinity test. Everybody else had dark glasses, and the
people at six miles couldn't see it because they were all told to lie on the
floor. I'm probably the only guy who saw it with the human eye.
Finally, after about a minute and a half, there's suddenly a tremendous
noise -- BANG, and then a rumble, like thunder -- and that's what convinced
me. Nobody had said a word during this whole thing. We were all just
watching quietly. But this sound released everybody -- released me
particularly because the solidity of the sound at that distance meant that
it had really worked.
The man standing next to me said, "What's that?"
I said, "That was the Bomb."
The man was William Laurence. He was there to write an article
describing the whole situation. I had been the one who was supposed to have
taken him around. Then it was found that it was too technical for him, and
so later H. D. Smyth came and I showed him around. One thing we did, we went
into a room and there on the end of a narrow pedestal was a small
silver-plated ball. You could put your hand on it. It was warm. It was
radioactive. It was plutonium. And we stood at the door of this room,
talking about it. This was a new element that was made by man, that had
never existed on the earth before, except for a very short period possibly
at the very beginning. And here it was all isolated and radioactive and had
these properties. And we had made it. And so it was tremendously valuable.
Meanwhile, you know how people do when they talk -- you kind of jiggle
around and so forth. He was kicking the doorstop, you see, and I said, "Yes,
the doorstop certainly is appropriate for this door." The doorstop was a
ten-inch hemisphere of yellowish metal-gold, as a matter of fact.
What had happened was that we needed to do an experiment to see how
many neutrons were reflected by different materials, in order to save the
neutrons so we didn't use so much material. We had tested many different
materials. We had tested platinum, we had tested zinc, we had tested brass,
we had tested gold. So, in making the tests with the gold, we had these
pieces of gold and somebody had the clever idea of using that great ball of
gold for a doorstop for the door of the room that contained the plutonium.
After the thing went off, there was tremendous excitement at Los
Alamos. Everybody had parties, we all ran around. I sat on the end of a jeep
and beat drums and so on. But one man, I remember, Bob Wilson, was just
sitting there moping.
I said, "What are you moping about?" He said, "It's a terrible thing
that we made." I said, "But you started it. You got us into it." You see,
what happened to me -- what happened to the rest of us -- is we started for
a good reason, then you're working very hard to accomplish something and
it's a pleasure, it's excitement. And you stop thinking, you know; you just
stop. Bob Wilson was the only one who was still thinking about it, at that
moment.
I returned to civilization shortly after that and went to Cornell to
teach, and my first impression was a very strange one. I can't understand it
any more, but I felt very strongly then. I sat in a restaurant in New York,
for example, and I looked out at the buildings and I began to think, you
know, about how much the radius of the Hiroshima bomb damage was and so
forth... How far from here was 34th Street?... All those buildings, all
smashed -- and so on. And I would go along and I would see people building a
bridge, or they'd be making a new road, and I thought, they're crazy, they
just don't understand, they don't understand. Why are they making new
things? It's so useless.
But, fortunately, it's been useless for almost forty years now, hasn't
it? So I've been wrong about it being useless making bridges and I'm glad
those other people had the sense to go ahead.
--------
Safecracker Meets Safecracker
I learned to pick locks from a guy named Leo Lavatelli. It turns out
that picking ordinary tumbler locks -- like Yale locks -- is easy. You try
to turn the lock by putting a screwdriver in the hole (you have to push from
the side in order to leave the hole open). It doesn't turn because there are
some pins inside which have to be lifted to just the right height (by the
key). Because it is not made perfectly, the lock is held more by one pin
than the others. Now, if you push a little wire gadget -- maybe a paper clip
with a slight bump at the end -- and jiggle it back and forth inside the
lock, you'll eventually push that one pin that's doing the most holding, up
to the right height. The lock gives, just a little bit, so the first pin
stays up -- it's caught on the edge. Now most of the load is held by another
pin, and you repeat the same random process for a few more minutes, until
all the pins are pushed up.
What often happens is that the screwdriver will slip and you hear
tic-tic-tic, and it makes you mad. There are little springs that push the
pins back down when a key is removed, and you can hear them click when you
let go of the screwdriver. (Sometimes you intentionally let go of the
screwdriver to see if you're getting anywhere -- you might be pushing the
wrong way, for instance.) The process is something like Sisyphus: you're
always falling back downhill.
It's a simple process, but practice helps a lot. You learn how hard to
push on things -- hard enough so the pins will stay up, but not so hard that
they won't go up in the first place. What is not really appreciated by most
people is that they're perpetually locking themselves in with locks
everywhere, and it's not very hard to pick them.
When we started to work on the atomic bomb project at Los Alamos,
everything was in such a hurry that it wasn't really ready. All the secrets
of the project -- everything about the atomic bomb -- were kept in filing
cabinets which, if they had locks at all, were locked with padlocks which
had maybe only three pins: they were as easy as pie to open.
To improve security the shop outfitted every filing cabinet with a long
rod that went down through the handles of the drawers and that was fastened
by a padlock.
Some guy said to me, "Look at this new thing the shop put on -- can you
open the cabinet now?"
I looked at the back of the cabinet and saw that the drawers didn't
have a solid bottom. There was a slot with a wire rod in each one that held
a slidable piece (which holds the papers up inside the drawer). I poked in
from the back, slid the piece back, and began pulling the papers out through
the slot. "Look!" I said. "I don't even have to pick the lock."
Los Alamos was a very cooperative place, and we felt it our
responsibility to point out things that should be improved. I'd keep
complaining that the stuff was unsafe, and although everybody thought it was
safe because there were steel rods and padlocks, it didn't mean a damn
thing.
To demonstrate that the locks meant nothing, whenever I wanted
somebody's report and they weren't around, I'd just go in their office, open
the filing cabinet, and take it out. When I was finished I would give it
back to the guy: "Thanks for your report."
"Where'd you get it?"
"Out of your filing cabinet."
"But I locked it!"
"I know you locked it. The locks are no good."
Finally some filing cabinets came which had combination locks on them
made by the Mosler Safe Company. They had three drawers. Pulling the top
drawer out would release the other drawers by a catch. The top drawer was
opened by turning a combination wheel to the left, right, and left for the
combination, and then right to number ten, which would draw back a bolt
inside. The whole filing cabinet could be locked by closing the bottom
drawers first, then the top drawer, and spinning the combination wheel away
from number ten, which pushed up the bolt.
These new filing cabinets were an immediate challenge, naturally. I
love puzzles. One guy tries to make something to keep another guy out; there
must be a way to beat it!
I had first to understand how the lock worked, so I took apart the one
in my office. The way it worked is this: There are three discs on a single
shaft, one behind the other; each has a notch in a different place. The idea
is to line up the notches so that when you turn the wheel to ten, the little
friction drive will draw the bolt down into the slot generated by the
notches of the three discs.
Now, to turn the discs, there's a pin sticking out from the back of the
combination wheel, and a pin sticking up from the first disc at the same
radius. Within one turn of the combination wheel, you've picked up the first
disc.
On the back of the first disc there's a pin at the same radius as a pin
on the front of the second disc, so by the time you've spun the combination
wheel around twice, you've picked up the second disc as well.
Keep turning the wheel, and a pin on the back of the second disc will
catch a pin on the front of the third disc, which you now set into the
proper position with the first number of the combination.
Now you have to turn the combination wheel the other way one full turn
to catch the second disc from the other side, and then continue to the
second number of the combination to set the second disc.
Again you reverse direction and set the first disc to its proper place.
Now the notches are lined up, and by turning the wheel to ten, you open the
cabinet.
Well, I struggled, and I couldn't get anywhere. I bought a couple of
Safecracker books, but they were all the same. In the beginning of the book
there are some stories of the fantastic achievements of the safecracker,
such as the woman caught in a meat refrigerator who is freezing to death,
but the safecracker, hanging upside down, opens it in two minutes. Or there
are some precious furs or gold bullion under water, down in the sea, and the
safecracker dives down and opens the chest.
In the second part of the book, they tell you how to crack a safe.
There are all kinds of ninny-pinny, dopey things, like "It might be a good
idea to try a date for the combination, because lots of people like to use
dates." Or "Think of the psychology of the owner of the safe, and what he
might use for the combination." And "The secretary is often worried that she
might forget the combination of the safe, so she might write it down in one
of the following places -- along the edge of her desk drawer, on a list of
names and addresses..." and so on.
They did tell me something sensible about how to open ordinary safes,
and it's easy to understand. Ordinary safes have an extra handle, so if you
push down on the handle while you're turning the combination wheel, things
being unequal (as with locks), the force of the handle trying to push the
bolt down into the notches (which are not lined up) is held up more by one
disc than another. When the notch on that disc comes under the bolt, there's
a tiny click that you can hear with a stethoscope, or a slight decrease in
friction that you can feel (you don't have to sandpaper your fingertips),
and you know, "There's a number!"
You don't know whether it's the first, second, or third number, but you
can get a pretty good idea of that by finding out how many times you have to
turn the wheel the other way to hear the same click again. If it's a little
less than once, it's the first disc; if it's a little less than twice, it's
the second disc (you have to make a correction for the thickness of the
pins).
This useful trick only works on ordinary safes, which have the extra
handle, so I was stymied.
I tried all kinds of subsidiary tricks with the cabinets, such as
finding out how to release the latches on the lower drawers, without opening
the top drawer, by taking off a screw in front and poking around with a
piece of hanger wire.
I tried spinning the combination wheel very rapidly and then going to
ten, thus putting a little friction on, which I hoped would stop a disc at
the right point in some manner. I tried all kinds of things. I was
desperate.
I also did a certain amount of systematic study. For instance, a
typical combination was 69-32-21. How far off could a number be when you're
opening the safe? If the number was 69, would 68 work? Would 67 work? On the
particular locks we had, the answer was yes for both, but 66 wouldn't work.
You could be off by two in either direction. That meant you only had to try
one out of five numbers, so you could try zero, five, ten, fifteen, and so
on. With twenty such numbers on a wheel of 100, that was 8000 possibilities
instead of the 1,000,000 you would get if you had to try every single
number.
Now the question was, how long would it take me to try the 8000
combinations? Suppose I've got the first two numbers right of a combination
I'm trying to get. Say the numbers are 69-32, but I don't know it -- I've
got them as 70-30. Now I can try the twenty possible third numbers without
having to set up the first two numbers each time. Now let's suppose I have
only the first number of the combination right. After trying the twenty
numbers on the third disc, I move the second wheel only a little bit, and
then do another twenty numbers on the third wheel.
I practiced all the time on my own safe so I could do this process as
fast as I could and not get lost in my mind as to which number I was pushing
and mess up the first number. Like a guy who practices sleight of hand, I
got it down to an absolute rhythm so I could try the 400 possible back
numbers in less than half an hour. That meant I could open a safe in a
maximum of eight hours -- with an average time of four hours.
There was another guy there at Los Alamos named Staley who was also
interested in locks. We talked about it from time to time, but we weren't
getting anywhere much. After I got this idea how to open a safe in an
average time of four hours, I wanted to show Staley how to do it, so I went
into a guy's office over in the computing department and asked, "Do you mind
if I use your safe? I'd like to show Staley something."
Meanwhile some guys in the computing department came around and one of
them said, "Hey, everybody; Feynman's gonna show Staley how to open a safe,
ha, ha, ha!" I wasn't going to actually open the safe; I was just going to
show Staley this way of quickly trying the back two numbers without losing
your place and having to set up the first number again.
I began. "Let's suppose that the first number is forty, and we're
trying fifteen for the second number. We go back and forth, ten; back five
more and forth, ten; and so on. Now we've tried all the possible third
numbers. Now we try twenty for the second number: we go back and forth, ten;
back five more and forth, ten; back five more and forth, CLICK!" My jaw
dropped: the first and second numbers happened to be right!
Nobody saw my expression because my back was towards them. Staley
looked very surprised, but both of us caught on very quickly as to what
happened, so I pulled the top drawer out with a flourish and said, "And
there you are!"
Staley said, "I see what you mean; it's a very good scheme" -- and we
walked out. Everybody was amazed. It was complete luck. Now I really had a
reputation for opening safes.
It took me about a year and a half to get that far (of course, I was
working on the bomb, too!) but I figured that I had the safes beaten, in the
sense that if there was a real difficulty -- if somebody was lost, or dead,
and nobody else knew the combination but the stuff in the filing cabinet was
needed -- I could open it. After reading what preposterous things the
safecrackers claimed, I thought that was a rather respectable
accomplishment.
We had no entertainment there at Los Alamos, and we had to amuse
ourselves somehow, so fiddling with the Mosler lock on my filing cabinet was
one of my entertainments. One day I made an interesting observation: When
the lock is opened and the drawer has been pulled out and the wheel is left
on ten (which is what people do when they've opened their filing cabinet and
are taking papers out of it), the bolt is still down. Now what does that
mean, the bolt is still down? It means the bolt is in the slot made by the
three discs, which are still properly lined up. Ahhhh!
Now, if I turn the wheel away from ten a little bit, the bolt comes up;
if I immediately go back to ten, the bolt goes back down again, because I
haven't yet disturbed the slot. If I keep going away from ten in steps of
five, at some point the bolt won't go back down when I go back to ten: the
slot has just been disturbed. The number just before, which still let the
bolt go down, is the last number of the combination!
I realized that I could do the same thing to find the second number: As
soon as I know the last number, I can turn the wheel around the other way
and again, in lumps of five, push the second disc bit by bit until the bolt
doesn't go down. The number just before would be the second number.
If I were very patient I would be able to pick up all three numbers
that way, but the amount of work involved in picking up the first number of
the combination by this elaborate scheme would be much more than just trying
the twenty possible first numbers with the other two numbers that you
already know, when the filing cabinet is closed.
I practiced and I practiced until I could get the last two numbers off
an open filing cabinet, hardly looking at the dial. Then, when I'd be in
some guy's office discussing some physics problem, I'd lean against his
opened filing cabinet, and just like a guy who's jiggling keys
absent-mindedly while he's talking, I'd just wobble the dial back and forth,
back and forth. Sometimes I'd put my finger on the bolt so I wouldn't have
to look to see if it's coming up. In this way I picked off the last two
numbers of various filing cabinets. When I got back to my office I would
write the two numbers down on a piece of paper that I kept inside the lock
of my filing cabinet. I took the lock apart each time to get the paper -- I
thought that was a very safe place for them.
After a while my reputation began to sail, because things like this
would happen: Somebody would say, "Hey, Feynman! Christy's out of town and
we need a document from his safe -- can you open it?"
If it was a safe I knew I didn't have the last two numbers of, I would
simply say, "I'm sorry, but I can't do it now; I've got this work that I
have to do." Otherwise, I would say, "Yeah, but I gotta get my tools." I
didn't need any tools, but I'd go back to my office, open my filing cabinet,
and look at my little piece of paper: "Christy -- 35, 60." Then I'd get a
screwdriver and go over to Christy's office and close the door behind me.
Obviously not everybody is supposed to be allowed to know how to do this!
I'd be in there alone and I'd open the safe in a few minutes. All I had
to do was try the first number at most twenty times, then sit around,
reading a magazine or something, for fifteen or twenty minutes. There was no
use trying to make it look too easy; somebody would figure out there was a
trick to it! After a while I'd open the door and say, "It's open."
People thought I was opening the safes from scratch. Now I could
maintain the idea, which began with that accident with Staley, that I could
open safes cold. Nobody figured out that I was picking the last two numbers
off their safes, even though -- perhaps because -- I was doing it all the
time, like a card sharp walking around all the time with a deck of cards.
I often went to Oak Ridge to check up on the safety of the uranium
plant. Everything was always in a hurry because it was wartime, and one time
I had to go there on a weekend. It was Sunday, and we were in this fella's
office -- a general, a head or a vice president of some company, a couple of
other big muck-a-mucks, and me. We were gathered together to discuss a
report that was in the fella's safe -- a secret safe -- when suddenly he
realized that he didn't know the combination. His secretary was the only one
who knew it, so he called her home and it turned out she had gone on a
picnic up in the hills.
While all this was going on, I asked, "Do you mind if I fiddle with the
safe?"
"Ha, ha, ha -- not at all!" So I went over to the safe and started to
fool around.
They began to discuss how they could get a car to try to find the
secretary, and the guy was getting more and more embarrassed because he had
all these people waiting and he was such a jackass he didn't know how to
open his own safe. Everybody was all tense and getting mad at him, when
CLICK! -- the safe opened.
In 10 minutes I had opened the safe that contained all the secret
documents about the plant. They were astonished. The safes were apparently
not very safe. It was a terrible shock: All this "eyes only" stuff, top
secret, locked in this wonderful secret safe, and this guy opens it in ten
minutes! Of course I was able to open the safe because of my perpetual habit
of taking the last two numbers off. While in Oak Ridge the month before, I
was in the same office when the safe was open and I took the numbers off in
an absent-minded way -- I was always practicing my obsession. Although I
hadn't written them down, I was able to vaguely remember what they were.
First I tried 40-15, then 15-40, but neither of those worked. Then I tried
10-45 with all the first numbers, and it opened.
A similar thing happened on another weekend when I was visiting Oak
Ridge. I had written a report that had to be OKed by a colonel, and it was
in his safe. Everybody else keeps documents in filing cabinets like the ones
at Los Alamos, but he was a colonel, so he had a much fancier, two-door safe
with big handles that pull four 3/4-inch-thick steel bolts from the frame.
The great brass doors swung open and he took out my report to read.
Not having had an opportunity to see any really good safes, I said to
him, "Would you mind, while you're reading my report, if I looked at your
safe?"
"Go right ahead," he said, convinced that there was nothing I could do.
I looked at the back of one of the solid brass doors, and I discovered that
the combination wheel was connected to a little lock that looked exactly the
same as the little unit that was on my filing cabinet at Los Alamos. Same
company, same little bolt, except that when the bolt came down, the big
handles on the safe could then move some rods sideways, and with a bunch of
levers you could pull back all those 3/4-inch steel rods. The whole lever
system, it appeared, depends on the same little bolt that locks filing
cabinets.
Just for the sake of professional perfection, to make sure it was the
same, I took the two numbers off the same way I did with the filing cabinet
safes.
Meanwhile, he was reading the report. When he'd finished he said, "All
right, it's fine." He put the report in the safe, grabbed the big handles,
and swung the great brass doors together. It sounds so good when they close,
but I know it's all psychological, because it's nothing but the same damn
lock.
I couldn't help but needle him a little bit (I always had a thing about
military guys, in such wonderful uniforms) so I said, "The way you close
that safe, I get the idea that you think things are safe in there."
"Of course."
"The only reason you think they're safe in there is because civilians
call it a 'safe.' " (I put the word "civilians" in there to make it sound as
if he'd been had by civilians.)
He got very angry. "What do you mean -- it's not safe?"
"A good safecracker could open it in thirty minutes."
"Can you open it in thirty minutes?"
"I said a good safecracker. It would take me about forty-five."
"Well!" he said. "My wife is waiting at home for me with supper, but
I'm gonna stay here and watch you, and you're gonna sit down there and work
on that damn thing for forty-five minutes and not open it!" He sat down in
his big leather chair, put his feet up on his desk, and read.
With complete confidence I picked up a chair, carried it over to the
safe and sat down in front of it. I began to turn the wheel at random, just
to make some action.
After about five minutes, which is quite a long time when you're just
sitting and waiting, he lost some patience: "Well, are you making any
progress?"
"With a thing like this, you either open it or you don't."
I figured one or two more minutes woul