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Oral History Transcript — Dr. Robert Leighton

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Interview with Dr. Robert Leighton
By David DeVorkin
At Downs Laboratory, Cal Tech, California
July 29, 1977

open tab View abstract

Robert Leighton; July 29, 1977

ABSTRACT: Topics discussed include: early schooling in Los Angeles; family background; interests in mechanical design and new techniques; Los Angeles Astronomical Society; schooling at Los Angeles City College and Caltech; early career choices; changes of interest; medical van de Graaff project; experiences at Caltech during World War II; interests and work in rocketry; engineering courses at Caltech; Carl Anderson and development of interest in particle physics and cosmic rays; development of interests in planetary and solar astronomy; access to Mt. Wilson. Students, colleagues and funding at Caltech; work on solar cycle; research philosophy and choice of projects; Mariner and other space projects; ground-based astronomy; support patterns in astronomy; Kitt Peak; relationship of Hale Observatories and Caltech.

Transcript

Session I | Session II

DeVorkin:

Dr. Leighton, I know that you were born in 1919 in Detroit. I'd like to take you back to that time, and learn a little more about your family origins, your early influences, schooling, that sort of thing.

Leighton:

Well, my father was a tool and die maker for Packard, as I understand. (I didn't really know him very well when I was older, so I donít know too much about his background.) He was a machinist. Maybe still is, he may still be alive. My mother and father were separated when I was very young. But I suppose some of my mechanical aptitudes or interests are really genetic. I didn't learn it from my father, but Iíve often thought that he and I would have had a lot in common, if we had been able to see more of each other.

DeVorkin:

The separation occurred before you really knew your father?

Leighton:

Yes. Pretty much. I was young enough that I donít have any real recollection. I have only spotty recollections of any family activities. There was an automobile trip to Washington State. And I have a dim recollection of being in a rowboat with a Hills Brothers coffee can. You know how those funny things are—I canít place it or anything, but I think my mother said it was on, what's the lake near Mt. St. Helen's? Shadow Lake? At any rate, that's about the earliest I can remember.

DeVorkin:

Did your mother remarry?

Leighton:

Yes. Well, she lived in a common law marriage with my stepfather. That went until I was in college. Then there was a separation there too.

DeVorkin:

What was your mother's background, then? Would you say she1s the strongest influence on you?

Leighton:

Oh yes. Very much. She was born in Wisconsin. I have family records but I haven't paid too much attention to them. Either her father or her grandfather was a guide up in the North woods area in Wisconsin. I donít know how she and my father got together. He was born in Escanaba in Michigan—the same general neck of the woods. It's on the north peninsula.

DeVorkin:

Was your father's name Leighton, then?

Leighton:

Yes.

DeVorkin:

So you retained his name.

Leighton:

Yes. That's right. He had some brothers but I have had no real contact with them.

DeVorkin:

Did your mother have a college education?

Leighton:

No. Possibly high school. But she was good at numbers. She prided herself on the accuracy of her accounting. She was an accountant for a while. But she had no formal schooling other than public school up through whatever age one went in the early 1900's.

DeVorkin:

Did she have specific interests, in your education?

Leighton:

In a detached sort of way. She first heard about Ca1 Tech, I suppose, reading in the papers and magazines, and then the Mount Wilson telescopes were big news around the middle twenties when I was a young child. She used to make remarks that I would some day go to Cal Tech. But nothing she did, other than planting the seeds, really directly led me there. I think it was a random walk, almost. But I did get excellent schoolings in the sense that the public schools I went to in Los Angeles were very good. For examples I was well into college before I got to a level of chemistry that was better than I got in high school. And they were fairly good colleges—you knows LA City College and Cal Tech.

DeVorkin:

You didn't start at Cal Tech?

Leighton:

No. I went two years to LA City College (on the old UCLA campus on Vermont Avenue), then I transferred to Cal Tech as a junior. And that was largely with the help and more or 1ess—not the initiatives but the suggestion and strong help of a physics professor over at LA City College.

DeVorkin:

What was his name? Weíll get back to that.

Leighton:

That's Ralph Winger. He's still a1ives and living over right next to LA City College.

DeVorkin:

How long did you stay in the Michigan area?

Leighton:

Well, my earliest recollections in terms of school are when I was just starting grammar school down in North Long Beach. So, from the age of 4 or 5, I've been on the West Coast. Now, I think we lived in Seattle for a few months or a year or something, but I don't really recall it.

DeVorkin:

Do you know what brought your family to the Los Angeles area?

Leighton:

I don't know.

DeVorkin:

That was quite early in the twenties.

Leighton:

I guess if you lived through the winters in the North Peninsula of Michigan, you were happy to go to California. But this was the earliest twenties, then.

DeVorkin:

Did your mother move here with you and possibly brothers or sisters?

Leighton:

I'm an only child.

DeVorkin:

With your step-father?

Leighton:

Yes. That's essentially what happened. The separation came when I was just three or four, and then they moved out here.

DeVorkin:

What did your step-father do?

Leighton:

He was a mechanically inclined person. He had a great influence on my life also. His name was Sauer, John B. Sauer. But he was more in the automotive direction. He had a brother who had an automobile paint shop, and during the Depression when work was difficult, he worked with his brother there, and I also swept the floors, for two bits, to get Saturday matinee change. But in terms of what you might call the building of character, he was very influential and positive. I really admired him. I'm not sure he ever knew how much I admired him. You know how those things are. Kids don't have enough perspective to see a situation. But I now realize that he was a very great influence on me. Iíve often wanted to tell him so, but by the time I was out from under the wing, and had independent perspective, they had separated, and I didn't know his whereabouts either. And I don't know very much about the details of my mother's personal reasons for these things, so I really can't go into that.

DeVorkin:

I would be interested primarily in terms of how it would have affected your home life. What interests did you develop, as a child growing up in Long Beach?

Leighton:

Well, you might laugh. I can't believe that it really was [this way]. I don't know whether it's intrinsic, or whether I just had a very happy time with certain things, but the kinds of things that really turned me on were, of course, electric trains, naturally, and mechanical things. My mother would never trust me with an alarm clock. That kind of thing. Even when I got to the point where I would fix it instead of just tearing it apart. But also Erector sets and Tinker Toys even earlier than that. Then, when you hear what I'm doing—I'm now building some radio dishes with 828 pieces. They fit together just about like Tinker Toys!

DeVorkin:

This is a model of such an instrument? (Discussing a 1/20 scale model of a 10-meter radio telescope.)

Leighton:

It's a model of the 10 meter dishes that we're currently building. My current research activity is really an engineering one. I have designed and we're now building radio telescopes for millimeter wave radio astronomy, and it turns out that the method we're using is just a great big Erector Set. People kid me about that.

DeVorkin:

That's interesting, your origins. Do you recall your stepfather or your mother making these sets available, or did you really seek them out?

Leighton:

Oh, they were provided. That is, I would get them for Christmas, and when I got into junior high school, I was even making more tracks for the train in the metal shop, and doing creative things in the sense of building pieces and doing things like that. I've always been at least as much interested in building things and designing things as in actually using them. It's a little hard to say, you know, where one's scientific interests start, but I am interested in the observational equipment and doing new things, looking at things in new ways. I think if there was a theme, that's it. That theme would be in many of my projects.

DeVorkin:

I understand a little better how your mother was aware of Ca1 Tech, because you were in the Long Beach area.

Leighton:

That's right.

DeVorkin:

So as you started going to school, and came in contact with other people and influences, did you start reading a lot? Or did you always remain sort of externally interested in mechanical things?

Leighton:

No, I read avidly. And I think this culminated just about the time I graduated from high school, and I didn't really have any college plans. You'll have to remember, I graduated from high school in 1936. Well, I took a college preparatory course in high school because there was a choice, and I somehow had the sense to do that. It's my impression that I made that choice. I don't remember asking my parents about it.

DeVorkin:

Really?

Leighton:

In high school. I went to Poly High School in LA, Polytechnic High School, which at that time was down on Washington and Flower Streets.

DeVorkin:

What was the name of it?

Leighton:

The John H. Francis Polytechnic High School. Imagine that in a yell! (Laughter)

DeVorkin:

How far was that from your home?

Leighton:

It was walking distance, when I started there, but then we moved farther to the southwest. We were living at that time very close to what is now part of the Harbor Freeway, very close to the center of Los Angeles, but of course you could, in those days. I would roller skate to the library. I really used the LA Public Library. You were asking about reading. I think my earliest interest in mathematical and scientific things came in junior high school, at a level of say 9th grade or so, middle junior high. I went to three different junior highs—one, Compton Junior High for the 7th grade. Then there was one which is now under the Freeway, Sentous. I went in the last year it was operable, before they made it into just a Board of Education repository of some kind. Now it's torn down and the Freeway goes over it. Then I went to Berendo Junior High School, a little bit west of Vermont Avenue, for the 9th grade. That was the last year then of junior high school, before I went to high school.

DeVorkin:

Were you moving around at this time?

Leighton:

Well, we moved from North Long Beach into Los Angeles, after the 7th grade. We did move twice. I don't know what it was, but there were difficulties with income around that time, so I remember it as going downward in housing quality.

DeVorkin:

There was never any question that you would continue your education?

Leighton:

Oh no, never. Never. And that's very interesting, that even though work was hard to find, there was no pressure from either of my parents to go out and get a job, or "for God's sake, quit reading all those books," or anything like that. Nothing at all. As a matter of fact, the things that I did that were in any way remarkable in school, you know, in terms of grades—I wasn't a very remarkable student really—were approved by my parents. They liked that. They weren't pushing me to go to college or anything, but it was interesting that I had good approving reception at home for that. So that must have had some influence on me. Anyway, right around the 9th grade, I first got into algebra, and seeing linear simultaneous equations solved was really a bright light. I remember thinking, "Oh, boy, that's really great." About the same time, there was a general science course which had a number of things in it, but one of the things was astronomy. And just at that moment, I was receptive to such things, and I think you could say that that was the beginning of my conscious interest in astronomy.

DeVorkin:

In the mid-thirties.

Leighton:

In the mid-thirties, say '34.

DeVorkin:

So to your recollection, you did not read any astronomy before that time.

Leighton:

No. Not really. There might have been a WORLD BOOK or something. I do remember something with planets and the edge of the sun that sort of intrigued me. But I can't remember a conscious active interest until possibly '33 or so. I was about 13.

DeVorkin:

Is that about when Griffith Observatory opened, or did it open later than that?

Leighton:

Right around that time. But I don't think I got to Griffith Observatory until high school. I'm not sure I even went until college. I knew it was there. But it wasn't that big an attraction. A high school friend of mine who is now an astronomer at Lick, was very directly instrumental in my getting interested in building telescopes. There was the Amateur Astronomy Society, which met at that time on 8th Street, and he was a member of it. This was George Herbig. He's probably on your list. He ought to be, anyway. He was building telescopes and was a variable star observer and all the good things, everything. He got me interested in it, and I joined the society and built telescopes.

DeVorkin:

Was he a classmate of yours?

Leighton:

Not really. He was a high school friend, but I don't remember ever being with him in a class. I think we were a year or so apart. In the same school. And he had an arthritic mother who died in the late thirties or so, and he was then pretty much on his own. I think he had a lot of friends among the amateur astronomers and they helped him go to UCLA. We compared notes because we were getting together at the Society. But I didn't take that route. It's a kind of interesting story. I don't know whether you are interested in these things. The high school courses I got at Poly High were very good. I got a good course in electricity, including AC circuitry, three phase, with complex impedances, and stuff like that, really good. And just a slight amount of electronics, but not much. I've been not very up on electronics, possibly because I didn't have the early introduction to it. Anyway, the electricity was very good. And then I got chemistry in the 11th and 12th grades, and the chemistry was excellent. As I said, I was well into college before I got to a higher level. And I seemed to really catch fire in that and there was an American Chemical Society contest for high school kids at the time. I was entered in that by my teacher, along with three or four others from his class. And it happened that I came in second, just after another (now) Cal Tech professor, Charlie Wilts. We first met, wearing our first suits, bought for the occasion, for the banquet, in Bullock's basement by our respective mothers. But anyway, the prizes in this contest were scholarships to college. There were three prizes. One was Cal Tech, one was Occidental, another was USC. The winner had the first choice, the next one had the second choice, and so forth. And for reasons that I have lost track of, Charlie, of course, chose Cal Tech. I chose USC, partly I guess because I lived close by there and I didn't know anything about Occidental. But when I showed up at USC to register, it became very apparent that that just wasn't my school. You can understand why. In the middle thirties, it was very much of a football, rah, rah, rah business school type of thing, and although I'm sure that they had some chemistry and the like, it just wasn't the thing that I would have profited from as much. They don't have much astronomy. I somehow sensed that fraternity atmosphere, and I was living in this little place in southwest LA, and the fraternity guys showed up at the door, and here's this little shack—God, it was awful! I'm sure that helped me decide that really wasn't for me. So I went back to high school for a postgraduate year.

DeVorkin:

That's interesting, you could do that at the time.

Leighton:

Yes, I could do that, and I took photography, which was a great help, and solid geometry and a couple of other things. It was only a part-time program.

DeVorkin:

What was the nature of a program like that?

Leighton:

One got approval to do it, and then you did it.

DeVorkin:

You actively pursued this and your parents aided you in it?

Leighton:

I can't remember that. There weren't any fees or anything. And the carfare was 3-1/2 cents.

DeVorkin:

There wasn't any question of another school, such as UCLA?

Leighton:

Well, it was partly a transportation problem. UCLA was across LA. I couldn't get there on a regular basis. I didn't have a car.

DeVorkin:

And there was no hope of being supported to the extent of living there.

Leighton:

Oh no. One didn't even think of something like that. Then it developed that I heard about LA City College, during this year, and so I went there the following year.

DeVorkin:

Let me ask you the names of the teachers of chemistry and general science. Who in your public school education was most influential? Your chemistry teacher seems to have been important, do you recall his name?

Leighton:

Yes: Milo S. Moore. He was a PhD. And the electricity was taught by Mr. Avenel V. Downs. He was very good, too.

DeVorkin:

How did you become aware of the Los Angeles Astronomical Society?

Leighton:

George Herbig.

DeVorkin:

Oh, this was through George Herbig.

Leighton:

Yes.

DeVorkin:

How much contact did you actually have with him?

Leighton:

Well, at school, we would be together at lunch, almost daily. Yes.

DeVorkin:

Which of course was a very difficult time economically, but interesting.

Leighton:

Oh yes. But I didn't feel that, you know. I didn't feel the economic difficulties. I knew t:,at they were there, and my parents, in terms of the shopping and everything. We were clearly stretching very small funds.

DeVorkin:

What kinds of topics did you talk about with George Herbig? What do you remember being the most common thing you'd talk about or the most fascinating? Did you talk about the observatories?

Leighton:

I don't remember. Well, he was interested in the sun at the time. I wasn't, particularly. But the Astronomy Society had a solar telescope, with a long focus objective, and a very good optician.

DeVorkin:

On 8th Street?

Leighton:

Yes. He was a member at the time. Thatís Jimmy Herron, who founded the Herron Optical Co. during the war. I think it is now part of Bausch and Lomb. And one of his hot shot opticians, somebody named Avery—I can find the name if need be, because it's referred to somewhere—was also a member, and they were very instrumental in getting good instruments there. They had a l2-inch telescope in the back yard. And at the monthly meetings of the Society, there would be astronomers from Mt. Wilson and other places who would come and give talks, and it was those talks—that was what really got me interested, I think. Then, just about the same time, I discovered astronomy books, and so I went through the LA Public Library, and there was a branch down where I lived, near LaBrea and Adams, and I would read all those and make notes, so I knew an awful lot of technical facts about things, all the normal things about the coordinates and time. I don't know much more about time today than I did then, I think. And the planets and the stars and all. I knew what was known at the time, in textbooks. I didn't know, at the research level, what people were doing.

DeVorkin:

Do you remember any specific texts you read at that time, just to give me an idea of the level?

Leighton:

Well, Menzel,[1] I remember, was one of the names.

DeVorkin:

The Harvard Series, do you think?

Leighton:

I don't think I got hold of the official textbook, what is that?

DeVorkin:

The HARVARD BOOKS ON ASTRONOMY, popular books.

Leighton:

Well, if they were popular, I would have gotten them if they were in the library. I just donít happen to remember. But there were a lot of British books, too. Oh, I was also going through all of the James Jeans, Herman Weyl, things of that kind, and relativity and stuff like that. Eddington.

DeVorkin:

Were these things fascinating you more than the nuts and bolts in astronomy at that time?

Leighton:

Oh, yes. It put me in the right direction. I think if I had been in a good position, or if I'd realized that that's what I wanted to do and could do it, I would have gone right ahead, but as it was, I didn't regard astronomy as a credible career. Nor physics, for that matter. I started out in chemical engineering because of the chemistry course in high school and the fact that I seemed to be good at it. I followed that in LA City College until I came up against how bad chemistry could be. (Laughter)

DeVorkin:

You mean industrial chemistry?

Leighton:

No, no, just the teaching of chemistry. The course at LACC was a great big lecture course, and very pedestrianly done, at a level that wasn't as good as I had in high school. Now, I can see they had problems too, because they had high school kids that didn't have much chemistry. But I appreciated what I'd had. Then I just lost my interest in chemistry. It got a little technical, too. There were some things about pH and solubility products and stuff which I didn't really understand, I guess because it was only explained in terms of formulas and not in terms of mechanisms.

DeVorkin:

At this time you were definitely thinking of an engineering-type career, applications, somehow.

Leighton:

No, I don't think you could say that, I wasn't thinking that far ahead. I didn't know what engineers did any more than anything else. I just don't know. So about that time, as a matter of fact, in high school, the interest in mathematics flared up also, until I was taking math books out of the LA Library. I heard about calculus. Some of my friends who had graduated and gone off to Cal Tech and other places, came back with these amazing stories, about how you could calculate how fast your shadow was going if you were walking under a street light, and so forth.

DeVorkin:

These kinds of things fascinated you the most? Being able to model reality?

Leighton:

Yes. And word problems always were good. I liked to figure out things. But anyway, I had this specific interest in calculus—let's see, what are they doing, I should get into that. So I took out books. But. I made the mistake of picking out something like A TREATISE ON THE DIFFERENTIAL CALCULUS—"let F (n) be a class of .... da da da," on page l. So I wasn't getting very far. Jut then I happened, in a used book shop, to stumble across a little green book, that I still own, by Palmer. He was big in textbooks at the time. It was called PRACTICAL CALCULUS FOR HOME STUDY. I bought the book, and I took it home and I worked through it. So by the time I showed up at LA City College, I had gone through differential calculus and half of integral calculus. I didn't have anything else to do in the summer, and I wasn't pushed out to get a job by my parents, so I'd sit around the house and read the SATURDAY EVENING POST stories when they came, in an hour, and then I'd spend the rest of the time solving calculus problems and reading astronomy books, and building telescopes. I was just free.

DeVorkin:

Pretty nice way to spend a summer, actually. Where did you build your telescopes, actually?

Leighton:

At the Society, they had a workshop, and I got to use the lathe there, too. That was my first introduction to actually turning things. There were some old geezers, you know—well, you know what I mean—45 (laughter), who would spend a lot of time around and God bless 'em, they helped us young people do things. And so, if we didn't know how to do something, they'd show us. There was a fellow who made eye pieces and sold them. He owned the house in which the thing was, in the back. But he also showed us how to thread things. It was really good. That was practical. I could have had that in high school, there was a machine shop and all that kind of thing, but I was circumventing that by taking the electricity and the algebra and the geometry.

DeVorkin:

Were people like George Carroll involved at that time?

Leighton:

No, I don't remember meeting George until a long time later.

DeVorkin:

Do you remember any of the names of the people? In the Society? You mentioned someone, Newton?

Leighton:

Newton? Yes. I don't even know his first name. I guess we called him "Isaac Newton" but clearly that wasn't it. He didn't seem to get the humor of that, or else maybe we weren't on the same humor level. There was a Mr. Cotton. He was very helpful. And I'm sure these are in the record somewhere. Oh, and there was Ralph Dietz. I remember him as much older than I was. He must have been in his mid-twenties, when I was in my l7s and l8s there! He later went out to China Lake Naval Lab, and did optical things there. I ran into him some years later, when I went up to give a talk about something. So I think heíd recognize my name. I'm not sure the others would, necessarily. They were just people around, and they were helpful at the time and I learned a lot from them, but not in a one to one thing saying, "If it hadn't been for him, I wouldn't have learned that," or anything. It was just an atmosphere. And you knew people who would show up, and they all had the same problems about their mirrors, and testing and things like that. But it was great to have that equipment. I then later built things at home. I made a l6-inch telescope, which I still work on at times, much later. It was very easy, compared to what it would have been, and because of that earlier experience at the level of "chewing gum and sealing wax."

DeVorkin:

Did you build a mirror grinding machine?

Leighton:

Yes. I started doing the l6-inch by hand, and immediately figured out that the 50-pound disk went back and forth only about as much as I went back and forth. And I didn't want to do that many pushups! So I spent the next several weekends making a machine, which was very helpful.

DeVorkin:

Making telescopes of this size is quite a commitment, economically as well as of your time. What did you think you were going to be doing with these telescopes?

Leighton:

Which ones? You're talking about the amateur ones?

DeVorkin:

Yes, up to the 16-inch, yes.

Leighton:

Well, actually, they didn't cost very much. A few dollars for the mirror kit. And the big deal was aluminizing, and one always tried to freeload aluminizing at Cal Tech.

DeVorkin:

I see, you made the 16 after you were associated there?

Leighton:

Yes. I was on the staff, indeed. But once you build a telescope, you never stop building telescopes, or thinking of it.

DeVorkin:

Thinking about telescopes.

Leighton:

Thinking about it. That's right.

DeVorkin:

Well, you got to Los Angeles City College, and you were there for two years?

Leighton:

That's right.

DeVorkin:

You had no formal exposure to astronomy at LACC?

Leighton:

No. No, there were no courses. I have never had a course in astronomy. So, I must be the world's oldest amateur. And I hope I never lose my standing. But no. I didn't ever follow it professionally. You can call me a—they have a name for us—they call us "half-astrophysicists."

DeVorkin:

Who called you that?

Leighton:

I think John Bahcall was the one who first pulled that on me. But he's about right.

DeVorkin:

That's an interesting term. Well, you came here with what in mind? First of all, you got here through, what was his name?

Leighton:

Ralph Winger. He and two others at LA City College were probably very influential on me and on Charlie Wilts also, and other students who came through. You know, really, a student who just looks back on who was influential would pick out these people as being especially influential. Ralph Winger, because he was interested in his students, and his interest went beyond just the classroom. He had access to a ranch, rustic sort of a cabin place, up on the north side of Palomar, and would make weekend parties with students. He'd take along a whole bunch of students. We'd sleep outdoors on mattresses. In the winter time it was sort of rough. You'd have to put a canvas over you to keep out the rain. But then we did outdoors stuff, and we got a lot of hiking and things done, and it was an intellectual atmosphere, in that we were all in the math and physics classes, and so our conversation was all technical, and he was a technically interested person.

DeVorkin:

This was before Palomar was built?

Leighton:

It was during. And one of the things we did a couple of times, during this two year period or so, was to hike the trail up the north side. And we could see the skeleton of the telescope dome going in up there. That was a matter of great interest. We would drive around also, and drive up the mountain on occasion. No, it was very much on our minds, and when I took my eight-inch telescope down to that ranch and mounted it, because the sky was so nice and dark. So that was again a good helpful thing to spur my interest. I could actually see some of the galaxies that Iíd seen in pictures of and everything. I didnít realize that you could see them in telescopes. Of course, I didnít seem to realize that somebody had to see them in telescopes, in order for them to be in the catalogue!

DeVorkin:

Do you remember any of the names of the astronomers who came down to talk at the LAAS?

Leighton:

It would have been all the Mt. Wilson ones. I remember A. H. Joy.

DeVorkin:

Was R. Richardson around at the time? He was on the staff.

Leighton:

Iím not sure. I donít think he came to the LA Amateur Society. I knew him a bit later. Anyway, two more teachers, if youíre interested in that sort of thing.

DeVorkin:

Sure.

Leighton:

My teachers at LA City College were the surveying teacher and another physics teacher, the physics teacher who taught the optics and astronomy parts of things. He taught a course in astronomy but we didnít take it for some reason. I guess we knew about as much as he was teaching. His name was Mr. Pheley. He was also interested in his students, and he ran a little mirror-making room there, and we would spend some time in that, also, some of us who were interested.

DeVorkin:

Thatís very interesting, that there was this kind of contact. How large was Los Angeles City College at that time? You said the chemistry classes were quite large and impersonal.

Leighton:

Well, I think there would be about three or four secions of an introductory calculus course.

DeVorkin:

Each with 20 or 30 people in it?

Leighton:

Yes, something like that. That would give you some idea of that aspect. There was of course drama and business administration and the usual things. The surveying course was very interesting, in that I was doing this engineering bit, you see, and that was one of the things that you needed to have, they thought at the time. Well, it was a good thing, you know, it was empirical, but it required precision, and it taught you some things. It had some mathematics in it, which was all very good-problem solving, things like that. But this teacher was a real old salt. We got more dirty stories in class than we did facts about surveying, you know. The very best high class dirty stories. Not just filthy stories. Really nice. I can't remember very many of them, but they brought down the house. About that time, girls were starting to be interested in taking surveying, and that was one of the impediments, having them in the class. He couldn't tell the same dirty stories. Anyway, he drummed into us the importance of self-criticism. of really questioning what you're doing. You know—"What stupid mistake am I making right now?" His motto was, "Stop and think." And I recall one high point. We were calibrating a tape, a 100 foot tape. So, you have the posts, and somebody's made a standard calibration of the length of the thing. You have the tape, and you have another fellow at the other end, trying to hold one end while you hold the other end. It's pulling with a spring balance. And it doesn't quite match. And you've got to make a correction. So the question is, is the correction plus or minus? If you get the wrong sign, of course, you're just doubling the error. So here is this instructor in this lab, standing right over us while we're doing it, so you can't think while he's standing right over you, and he's beating you on the head, he's saying, "Is the correction plus or minus? What's the correction? What's the correction?" I said, ďIt's plus .01 foot.Ē He looks at it. He says, "Stop and think! Stop and think! What's the correction? What's the correction?" I looked at it. I said, ďItís plus .01 foot.Ē He looked at it. He said, ďMy god, youíre right!Ē (Laughter) That sort of thing sort of stays with you then, you know. So anyway, a few episodes like that, and I must say that that really helped for lab courses or anything involving measurement. I have forgotten it most recently, you know. I now donít criticize myself as much as I should. But it was one of the big lessons I took away from there.

DeVorkin:

Thatís quite interesting.

Leighton:

Iím probably dwelling too much on these things.

DeVorkin:

No, this is the sort of thing that gives a good background to the way you do science. Itís delightful, also. Did they choose Cal Tech for you pretty much? Or did you want to go there, by that time?

Leighton:

Well, I think by that time it was clear that Cal Tech was the place. Charlie Wilts, who got this first prize in the chemistry thing, hadnít dome to Cal Tech for the same reason I hadnít gone to USC: we didnít have enough money, even with a scholarship.[2] So he went to LA city College, and I ran into him there, again. He was a year ahead of me, because he went directly, and I took this year out to go to high school. So he came over to Cal Tech a year before I did. Then we got scholarships, here, but only for tuition, of course. He commuted from South LA, and I had moved to Alhambra at the time, and just about that time, it was just my mother and I, because there had been that other separation. Then we later moved right up into Pasadena, within walking distance of the campus.

DeVorkin:

How was she able to do this? Job change?

Leighton:

Well, she was not working at the time. She had worked earlier, in the twenties, but not during the time when the hardest part of the Depression was. But it was pretty much hand to mouth. And I had campus jobs, and I know Ralph Winger also loaned money to me, you know, a few hundred dollars, which was really all it took, because the rent was modest, and it was a modest house, which is also under a freeway now! I seem to have a history of that. The place in Long Beach we lived in is also, if not under, itís adjacent to the Artesia Freeway. Iím telling you more probably about Southern California than about me.

DeVorkin:

It also gives me an idea of what you feel about it.

Leighton:

Yes, right.

DeVorkin:

Thatís interesting. Then you moved up here.

Leighton:

Yes, so we moved right up within a mile north of the campus, and so it was very economical. And I guess, as a matter of fact, we had a student or two rooming in the house, and that was part of the income, and so we squeaked by. And then, by that time, by the end of college, I was earning more money. I became involved in a van de Graaff generator for medical uses over in the Westlake district of LA, and worked on that, the summer and part of the following year after I graduated. I knew I was going to come back for graduate work, but I forget just how it was. I was holding that job while I was taking my first graduate courses here.

DeVorkin:

This is in Westlake?

Leighton:

It was near Westlake Park, MacArthur Park, now.

DeVorkin:

Let's go back to the time that you entered Cal Tech, I guess it would be as a junior?

Leighton:

Yes.

DeVorkin:

What were your goal interests at that time? Your career interests?

Leighton:

Well, I told you Iíd changed from chemical engineering. Iíd changed to electrical engineering. And I guess I entered Cal Tech in electrical engineering. I got my BS in EE. It was power engineering, of course. It was not electronics at that time. Now, electrical engineering is mostly silicon chips.

DeVorkin:

Right. Who were your teachers?

Leighton:

Here?

DeVorkin:

Yes.

Leighton:

Well, there were two very influential teachers, and Iím going to mention the names of both of them, but one of them was a negative influence. I worked for him, both as a student and technician, and then had classes from him as a teacher. And he was the one who convinced me I wasnít going to be an electrical engineer. Now, it wasn't that he was a bad teacher at all. It was just his whole point of view: there was nothing in the world but 60 cycles, lap and wave windings and shunt and series motors and that kind of thing. Now, I could understand those, but in the meantime, I had gotten into a course in mathematical physics. In the junior year there were elective things you could take, like Hydraulics or something like that. I took Introduction to Mathematical Physics. That was because I got interested in physics over at LA City College. I even got interested in this fantastic thing called calculus of variations, about the same way I did with calculus in high school. I started reading books on calculus of variations because I was fascinated by the notion that you could just make a condition, on a minimum time for a trajectory or something like that, and then out would come a differential equation. You could solve it, and there would be a curve you could name, like a cycloid or whatever. That was magic, you know. So I had to know more about it. So I was all hopped up about that. In this mathematical physics course, there was of course the variational principles for mechanics and things, and so I just ate that up.

DeVorkin:

Was this a large lecture course?

Leighton:

No, it was a small enough course. And the method at the time was, the students went to the blackboard to put problems on. We don't do that any more. We can't ask a student to solve a problem at the blackboard. Attitudes have changed: "Don't bother me, man, I've got important things to do." But, anyway, that was the way it happened at the time. His name was W. V. Houston, the physics professor, and he later went on to be president of Rice University. I started my thesis work under him also, on a theoretical problem.

DeVorkin:

Did you have any contact with the physics department formally, other than with Houston, as an undergraduate?

Leighton:

No. Not really.

DeVorkin:

But do you recall getting more and more interested?

Leighton:

Oh yes. Well, as a matter of fact, at that time, before and during the war, electrical engineering was part of the same division as physics. And so there was physics, applied physics, and electrical engineering, and I was in electrical engineering, probably because of a language requirement which I was negative about. I shouldn't have been but I was. It was a big mistake. But anyway, I was in electrical engineering. Anyway, the other professor's name was Francis Maxstadt.

DeVorkin:

He was the negative influence?

Leighton:

He was the negative influence, yes. I probably learned some very important things from him, but somehow or other, it just was ďso rote,Ē and didn't have mechanisms in it, didn't have any basic things, whereas I had some electricity in this physics course, mathematical physics, Maxwell's equations and Ampere's law and all that kind of thing. And all of a sudden, I understood what weíd been having in this electricity course, called "cross-magnetizing Ampere turns." And so I asked a question in class. I was taking these things simultaneously. I said, "Hell, isn't that just a matter of the integral of H∑dL = I?" He said, "Come again?"

DeVorkin:

I understand the problem.

Leighton:

So anyway, there was that. Then I guess you can say that I got to be more charitable to poor old Maxstadt. He was a good engineer. I just realized that that wasn't what I was after. And I did know what I was after. So I really realized I was going into physics, so that's the direction I went for graduate work, and as I say, I started on a theoretical problem involving lattice vibrational spectra, for Houston.

DeVorkin:

That's right, and that ended up in a publication.[3]

Leighton:

Yes.

DeVorkin:

Any other physicists that you recall being an influence upon you, either just by their presence or attending their lectures or whatever?

Leighton:

Well, Carl Anderson probably had overall more influence on my career than anybody else here. Houston, I think, was the hero, the awakening influence and so forth. He put things before me that I really was thirsty to know, and hadn't realized it up to then. I wrote a textbook since then,[4] and I patterned it very much after how Houston did things, because I admired his textbook at the time. It left a lot for the student to do. He would just sketch out how you do something, and then the next problem was to do it. So it was a little bit like the calculus, going through, learning and doing it. He ran his course the same way;

DeVorkin:

Your textbook has an interesting characteristic. You have a lot of exercise sections interspersed in the text.

Leighton:

That's where it came from. Some people don't like that, and other people think it's great.

DeVorkin:

There are some very interesting problems, especially as you get on to the last chapters dealing with astrophysics.

Leighton:

You looked at that, I see.

DeVorkin:

Yes, I peeked. Some of your questions about cosmic rays.

Leighton:

Yes.

DeVorkin:

And the amount of energy taken in by the earth from cosmic rays.

Leighton:

Yes, just orders of magnitude, kind of sets the stage.

DeVorkin:

A lot of that is of great interest to me because it seems to show, not only origins in particle physics, but how you also were always on the brink of astronomical interests, too.

Leighton:

Sure.

DeVorkin:

Can you describe how your general career evolved, as you went through Ca1 Tech, changed your major direction interest to physics? Did you start thinking about what you'd be doing later in life?

Leighton:

The strange thing, you have to recognize, is that starting in 1939, September, I have never left Cal Tech. Iíve never made it away from the place. So I'm a very special case. Iím just the epitome of ingrowth.

DeVorkin:

Yet you've changed; you evolved.

Leighton:

Yes. I don't regard myself as the same person at all, although I can see the things that I was interested in and doing at the time, that are now the things I emphasized and capitalized on and profited from. So Iím a bad person to ask about setting careers. I guess there were two conscious choices that I had to make, that would have put me in a different watershed. And that came just as I got my PhD degree, because up to the time that I got my PhD, I knew that I wanted to do that. I knew that I wanted to get a PhD, and to be in physics. But I didn't know quite what physics was as a career. I was just becoming conscious that you could be paid for it. Of course, it has lately become very true, but in those days it wasn't quite so clear. And in astronomy, even in that time, in the catalogue, it said people should realize that there are only a few jobs in astronomy, and only those with the most intense interest and who are willing to take their chances on jobs, should go into the field.

DeVorkin:

Did that keep you away from astronomy, to a certain extent?

Leighton:

I don't think I would have chosen astronomy at that point. I was very interested in it, but I still didn't think of it as a career. I don't know quite why.

DeVorkin:

Certainly the astronomy at Ca1 Tech was still very much in a growth period.

Leighton:

Oh yes, it was not very big. There wasn1t very much. F. Zwicky was the astronomer.

DeVorkin:

Thatís interesting. He was the campus astronomer.

Leighton:

J. J. Johnson also was here, and of course Anderson.

DeVorkin:

That would be J. A. Anderson?

Leighton:

J. A. Anderson, who was the head of the 200-inch project, was here. But Johnson and Anderson were nothing, as far as any influence on students was concerned. Iím sure that they were both worthwhile astronomers. Anderson, I think, did very good things, at the time, which led him into being head of that. I came to know him a bit later, while I was on the staff here. And he was a little too old. He just never accepted h, Planck's constant. He never really could come to grips with the idea that light comes in lumps. And rather than trying to fight with it and understand it and get a feeling for it, he just denied it, and kept thinking of counter examples.

DeVorkin:

Could that have anything to do with the fact that he was very much involved with F. Pease on Michelson's projects? Through the late teens, post World War I and the twenties.

Leighton:

Yes.

DeVorkin:

He was very, very keen on interferometry.

Leighton:

Yes.

DeVorkin:

Conceivably he was just thinking in terms of nothing but wave motion.

Leighton:

Yes. Well, he was very good at that. He knew how to think in those terms, and he kept thinking in those terms. But I was surprised to learn that about him, very, very late. But of course, as I say, he was a very old person at the time.

DeVorkin:

live often been interested in him, because he was incredibly inventive, instrumentally, and a tremendous aid to the people who were working on the interferometer beam on the 100-inch telescope.

Leighton:

Yes.

DeVorkin:

And yet, by the twenties, he was literally, I guess, in administration, designing the 200-inch, making sure everything was working right—and it seemed to be something more delegated by Hale than his own interests. Do you know anything about that?

Leighton:

I know nothing at all about that. I was not really on the scene quite early enough for that. I missed Hale. I don't remember even talking to Hale, or seeing him. But he was sort of around at the time when I first came here.

DeVorkin:

Right, just your first year possibly.

Leighton:

So you were asking about career choices and things. I said that there were two places. One was when I got my PhD, I had a choice of an industrial job, at Hughes, at the "astronomical" salary of $5000 a year. I still have the offer, letters, I think, in my file. Itís interesting. You could make a curve of salary versus time. I've never done it. Anyway, that was a concrete offer. And had I said "yes," I would have been a mogul in Hughes, Ramo-Woldridge, or else would have flunked out of it or something. I think the letter of appointment was from Woldridge, over at Hughes. That was before there was Ramo-Woldridge.

DeVorkin:

What did they want you to do?

Leighton:

I don't know. I've never known. I don't know, maybe they mentioned in the letter certain possibilities. But this would have been, of course, 1947, before space.

DeVorkin:

Right. Sure, but not much before.

Leighton:

Not much before.

DeVorkin:

I'm interested certainly in your graduate years, and how you finally ended up pretty much in solid state and then particle physics.

Leighton:

Well, the other concrete offer was from Houston, when he went off to be president of Rice University. But I stayed here to do my thesis. And I'd been working under him with the thesis, and he was interested in it, and held made me an offer to come to Rice as an assistant professor. Here's an offer from the president of the university. I actually went to the trouble to look up something about the area, and I was just turned off by the climate and the surroundings. In the meantime, I had an offer from Cal Tech, as a research fellow, largely through Carl Anderson. I worked with Carl Anderson during the war, on the rocket project here.

DeVorkin:

Yes, I wanted to certainly ask you about the war years.

Leighton:

So anyway, there was that offer of probably some $3500 from Rice. Had I taken that, I think I would have been more inclined to stay in solid state, because of Houston's influence that was pulling me in that direction. I took a lot of courses from him. I got out of the hydraulics course in the senior year here, and took Smythe's course in electricity. I donít know if you know Smytheís course by reputation? But it was the tough course. It was the thing that screened out the sheep from the goats in the graduate school in physics. I took it as an undergraduate. I took it as a senior, not to get it out of the way or anything, but because I was up to the level, and ready, and it was an elective and I could take it.

DeVorkin:

Did you find that you were accelerating more, or more capable than your contemporary students here? When did you realize that you would be capable of going on for a PhD and a career?

Leighton:

I guess, when I came here as a junior, I realized. I realized I was in the upper part of the class, no doubt about that.

DeVorkin:

There was no stigma coming from LACC?

Leighton:

Oh, no—it was positive. It was a good idea. I would recommend it sight unseen to anybody. Not that particular school, but to go for two years to a public junior college, one that has reasonable technical courses, and then come to Cal Tech. I hate to say it, but I think that the atmosphere here is just not right for a student to gain independence of thought, and responsibility, and to be self-motivated. The graduate school is beautiful, and the change is just like flicking a switch, to go from undergraduate school here. It isn't quite a country club atmosphere, but it's very much of a social atmosphere and a team atmosphere, as an undergraduate, in the student houses and in other things. It gets to be a little microcosm, with its own little machinery, and motivations, and so on. Night life. And you're influenced by your fellow students. You know, your hours are set by other people, things like that. It's very difficult. I would not have survived, I think, here as a freshman. But it worked just fine to be a junior. And I was living off campus, so I could keep doing my things off campus. It wasn't only through hard work that I knew—it was just that it was cumulative. I was interested. I worked. I learned things. And so I was ahead, it all sort of fit.

DeVorkin:

During your graduate days, you stayed living off campus?

Leighton:

That's right.

DeVorkin:

There was no question that you would go on to graduate school here, then.

Leighton:

No. I applied, and I was one of the upper people in the class, so it was automatic. I taught a section of freshman physics. That's where I really learned freshman physics. You know the way. And so things just went along.

DeVorkin:

Between your BS, which was in Ď41, and your MS in Ď44, was this when you did the war work?

Leighton:

Yes, to '45. I got the MS only because, it wasn't absolutely certain that one was going to be able to get a PhD. The candidacy exam, the oral exam was a real exam. So it was always a good idea to have an MS, people thought. Anyway the war was on, and there was some possibility of being drafted.

DeVorkin:

How did these pressures and influences cause you to go into the war work?

Leighton:

Well, I don't remember exactly, but I had this job over at the medical center with the van de Graaff. It got up to a point where I sort of had voltage on it. But I was having difficulty. I didn't really know about a van de Graaff. I was just an undergraduate, and there were certain design problems in the insulators. I didn't know anything about electron beam optics. I was just at a place in college where I could have started to figure it out, but didn't have the empirical experience, that I would have had if I'd been in Kellogg Lab, say, with the van de Graaff. So I was having a lot of trouble.

DeVorkin:

There were plenty of van de Graaffís around, but ...

Leighton:

—not for X-rays.

DeVorkin:

That's right. What was your actual responsibility? You were the one designing it and setting it up, or?

Leighton:

No. It had been designed, as a carbon copy of the small van de Graaff here in Kellogg, by a person who was a graduate student, under the guidance of Fowler and Lauritsen here. But because they made the Chinese copy, it wasn't felt that you had to do anything other than make machine drawings and get the parts made and put them together. But there were some subtleties about it. As I say, the insulators were made wrong. They broke down inside, and all those headaches showed up after the graduate student who was very eligible for the draft—this was just at the time of Pearl Harbor and so forth—moved away from that job. I was working for him on the job, at first, for a summer and part of a year, and he then moved over to the rocket project here, and very quickly moved up to Goldstone Testing Range, and later operated the Goldstone Testing Range.

DeVorkin:

Who was he?

Leighton:

Charlie Robinson. He got his PhD after the war with Ralph Smythe, I think, and then went on to Bell and Howell. He was instrumental in their galvanometer product line with the hot ribbon trace, that sort of thing, or something, I don't know, he did a lot of things with them.

DeVorkin:

OK, he definitely went into industrial research.

Leighton:

Yes, right. He's now in Santa Barbara. I've lost track of him. I don't know exactly what he's doing. But I'm sure he's successful.

DeVorkin:

I hope his house is all right in Santa Barbara. (Reference to Santa Barbara fire, summer Ď77.)

Leighton:

Yes, he's north. The north coast.

DeVorkin:

So you were left holding the bag?

Leighton:

I was left holding the bag, and it was regarded as a straightforward job to complete the thing, and stack the insulators up, put in the corona ladder and ďfire it up.Ē

DeVorkin:

Who were you working for at this time?

Leighton:

The doctor, Dr. Clyde Emery. And here was this poor callow student—I'm sure he lost a lot of money because of me, you know. I just wasn't competent. I found out about the thing, but I was sure learning as I went along, and I would get some beam downstairs, but then it would blow up because the electrons would out-gas the stuff on the inside of the tube, and then Iíd lose the vacuum, and it would spark. And just about that time, I saw the handwriting on the wall also, and realized that I wasnít going to be able to continue that. Anyway, I wanted to be sure that, to whatever extent Iíd get to finish schooling, I could do it, and so I also moved on to the rocket project here.

DeVorkin:

Was that through Carl Anderson?

Leighton:

Not through him. I forget exactly how it happened. I forget exactly who I saw and so on.

DeVorkin:

How did you hear about the rocket project?

Leighton:

Well, I knew about it because I was taking classes here, for part of the time, and they had just gotten started, and I knew some of the people on it. They weren't talking about what was happening, but I knew generally what the idea was.

DeVorkin:

Was there a certain cloak of secrecy around it?

Leighton:

Oh, yes. Very much. Guards at the door and all that kind of thing. It was an honest to God secret thing. I learned a lot of things, the second day I was on the project, that I should have regarded as obvious, knowing what I'd known before, but I hadn't.

DeVorkin:

Like what?

Leighton:

Well, like what rockets were good for. Everything, like the anti-submarine uses, from old PBY's, with their retro—when you have a hard time hitting a submarine with a depth charge or something, but if you have calibrated the air speed, and you know how fast your rockets go, you shoot them backward at the same speed the plane is shooting forward, and they go ďwwhttt,Ē straight down. You wait until the submarine is right below you, and say, ďNow!Ē And you got him.

DeVorkin:

You were working on guidance systems, or?

Leighton:

Not really. There was no such thing as guidance. It was simply launched and fin-stabilized. I was assigned to Carl Anderson's rocket launcher group, and we were concerned mostly with putting under-wing rocket launchers on fighter craft, mostly carrier-based Navy fighter craft, the F6F's and the F4U's. And I guess you could say we were reasonably successful, although we got the basic ideas for what we did from the British. They were ahead of us on that. And the name of the game was to put eight rockets under the aircraft wing, without slowing the plane down. Well, the rockets slowed it down, but when they were gone, you didn't want to have a lot of junk sitting out there, and the British had put these big rails out in front, to guide the rocket out. But then somebody realized, with the airplane going, that you already had some speed, so all you had to do was let go of the rocket, so all you needed was little studs sticking down. Then eventually, they even made retractable studs, so that when the rocket left, the studs went back up into the wing.

DeVorkin:

So you didn't work with the rockets themselves.

Leighton:

No, I really didn't, ever. Iíd go out to tests and things. But more likely than not, weíd be staying on the ground, and the pilot would be in the airplane, firing the things from the airplane. And even there, they didn't do ground tests. They were using water ranges.

DeVorkin:

What ranges?

Leighton:

Water ranges, because these were for anti-submarine as much as anything else—attack ships, anti-submarine—and the rockets had a property that wasn't understood for a while, but if they went in at a glancing angle, say 10 degrees or so to the water, they would come out. They would go to a maximum depth of a few feet, and come out again further on. This was analyzed later. The nose was making a cone, a bubble, and the back end of the rocket was skidding a curve and making itself come back out again. But that was a technical factor that was important to understand, because it was just about the depth the submarine was too, when you were going. Of course, if it was deeper, you had to be sure to dive down deeper, to be sure the rocket didn't come out again. So they used water range, Salton Sea and Haiwee Reservoir.

DeVorkin:

These were all solid fuel?

Leighton:

Solid fuel rockets, yes.

DeVorkin:

Had you heard of Goddard's work by that time?

Leighton:

Oh yes. Sure.

DeVorkin:

What was the general opinion of the people who were the rocket people here of Goddard's work?

Leighton:

I don't know. No, I don't think the people on this project would have [been invited]. That was certainly something totally different. Totally different. Because, you know, there were little tubes and things. They went all right, but I don't think anybody regarded it at the time as the forerunner of anything practical.

DeVorkin:

Nobody was talking or thinking about use of rocketry in space research? At that time?

Leighton:

No. Well, in general terms—"Some day, we will use rockets, and hydrogen/oxygen will be fuel," and stuff like that, but no practical things about how you would pump it and store it and things like that. No. I may be just out of contact. There are probably several, maybe von Karman over here in aeronautics—von Karman I'm sure was concerned about things like that.

DeVorkin:

There were reports by that time, weren't there, about V-l's and V-2ís?

Leighton:

Oh, yes. In fact, thatís the big thing we got into, was how to try to combat these funny looking things pointed toward England from the coast of France, which were thought to beóthey were the V-1 launch sites.

DeVorkin:

Right, those were the ones that could be seen. Not the V-2ís.

Leighton:

Yes. Not the V-2's. So that was very much on people's minds. But there the V-lís were these buzz bomb things, and the jet engine business was starting to go as an engine, but not as a rocket, propulsion. Iím just not clear—I'm sure I don't have good perspective.

DeVorkin:

Well, what Iím doing is trying to find any contact you may have had with space research at that time. Or interest in it. Did you read science fiction?

Leighton:

Well, I went through a peak in science fiction, in my late high school and early college years. I guess I still read it when I was coming to Cal Tech. But I stopped reading it abruptly right around 1940. And Iím not sure why, but I think partly because I was finding out things in science that were so much more spectacular. I didn't tell you that as a senior, I also got out of the hydraulics course, and took quantum mechanics. For an electrical engineer, you know, to take quantum mechanics [was unusual]. And the professor in hydraulics thought the real reason I did it was that the hydraulics course was too hard! The hydraulics professor looked at my petition and said, ďThat's a strange one, but I guess you know what you're doing,Ē and gave permission.

DeVorkin:

Too hard, in what way?

Leighton:

Oh, they had problems such as: you had an oil tank up on one hill and another oil tank on another hill, and they're both feeding through a single pipe. You want to know how fast the oil flows out at the bottom. And you've got to allow for the tubing bends, and it's nonlinear, and you have to—yech! Of course, I would have learned some good things there. As a matter of fact, I took strength of materials, and it was one of the most useful courses I took. Yes, I believe it. Statically indeterminate systems and stuff. A lot of it rubbed off on me, and I didn't know it at the time, so it's funny how things work out.

DeVorkin:

During these years, then, you would say that your war work did not really influence you one way or the other? It was just something you were doing? To be away from the draft, in a way?

Leighton:

In a way. That's right. I wouldn't say my primary motivation was to be away from the draft, but that was a sort of concern to everybody, and I don't think anybody was anxious to join the South Pacific forces.

DeVorkin:

In a more positive way, it was a way that you could stay within your discipline?

Leighton:

Yes, that's right, it was regarded as the way of contributing with the least disruption of your life, and that's the way it turned out.

DeVorkin:

You were in a project that was semi-secret or fully secret.

Leighton:

Yes.

DeVorkin:

Was it fully secret?

Leighton:

I think most of the things we did at the level here, on the campus, were called Confidential. There were some Secret aspects, which I probably never learned. But I wasn't personally involved with Secret things.

DeVorkin:

What about various physicists who began disappearing during the war, and going off to various places in the desert and various other places to do some other ďbigĒ Secret jobs? Has there anything in the air about it?

Leighton:

Only very late. Only a month before Hiroshima.

DeVorkin:

I see. This was not something that was being speculated upon by everybody in coffee table conversation?

Leighton:

No. Not at all. Either that or I was never there. I don't remember hearing anything about it. I don't remember whether in fact, there was a drop, and then it became fairly widely known that there was Site Y and so on like that. Iím sure people like Fowler and Lauritsen were in on it all the time.

DeVorkin:

They remained here?

Leighton:

Carl Anderson later showed me a telegram he got, asking him to come and head up the Los Alamos Lab. They actually got Robert Oppenheimer, when Carl Anderson didn't want to do it. I think it was probably a better choice, actually.

DeVorkin:

Why is that?

Leighton:

Well, I didn't know Oppenheimer well enough possibly to be able to compare the two, in terms of how they handle people. But if Carl had a fault, it was that he didn't want to tell anybody what to do.

DeVorkin:

Makes it difficult.

Leighton:

It's very difficult. And he was always very open and free and he would make suggestions, but there was never an order and never an assignment. I think he saw that in himself, and he just didn't want to have the responsibility for what was inevitably a terribly high pressure thing. He would have been good on the technical things, and overseeing the whole thing. But not at running things. He just wasn't built that way. It was probably a good choice, probably a good thing for him to [stay away from].

DeVorkin:

There was a lot of bomb-oriented research here at Cal Tech, and a number of astronomers, at least, I understand, were involved in detection devices, being able to examine the bomb trigger mechanism, and various things like that.

Leighton:

Well, that was part of our rocket-research, so-called, extended as part of it, after the first drops. I guess it was known. I really have forgotten the timing on that, but the Hiroshima drop was August of '45. Then the European business had ended earlier.

DeVorkin:

I know that a number of people here were involved.

Leighton:

Well, Iím not quite sure. I really donít know. But I knew that certain people were doing things, and I saw things on our dock and I knew, roughly, what the idea was. They had some pentagonal shapes of things, that had obviously been strongly shocked. They had been obviously with the implosion, what they were using, primer cord or something, to get the detonation to go equally, and they had these things, and you could see beautiful blue lines on them, where it was clear that they'd been terribly imploded, fantastic pressures, but they were measuring, you know, how uniform it was, and so on. Then we even did some electronics work near the end of things. And the one patent I hold is for a means to tell whether a number of things that are supposed to be simultaneous, were simultaneous. You can imagine what. Or whether there's scatter. And I invented a way to use thyratrons, to trigger the thyratrons, according to the order in which the pulses came in, and then, you'd read the things later, and they would hold their state, and you'd know the order and roughly the time base, the order in which they came.

DeVorkin:

What was the tolerance in the time base?

Leighton:

It was a microsecond or so. I donít know just what. But anyway, what little electronics I picked up was from a guy who's still around this area, and Iíd have to go to him several times. And he'd always use words I didn't understand. But then I'd pick up enough, so that I could ask him another question, but then I'd get part of the answer to the previous question, and I'd run him through again, until I knew all about filters and all about this and that.

DeVorkin:

Now, you said you got a patent for this. But you were doing this research at Cal Tech as a graduate student?

Leighton:

Well, I wasn't a graduate student, no. I was on the project. It was a project product, and it was turned in as a possibly patentable thing, and I guess somebody out at Los Alamos decided that it was worth patenting.

DeVorkin:

It was not under your name then?

Leighton:

Yes, my name is on it, but I got a dollar for it. You know, that usual business. I never heard of it again, and Iím sure it's lost in the file.

DeVorkin:

That was the basic question I had. I had the impression, maybe youíd personally patented it.

Leighton:

No, I've avoided patenting things. I don't know why.

DeVorkin:

Yes. It's understandable, considering all the problems. Did you ever have any interest in getting deeper into this kind of work?

Leighton:

Not really, per se. But Iím sure that there's a whole world involving transistors and digital logic and things that, if I had been started on a slightly different tack, in my electrical engineering years-if they'd ever heard of anything other than 60 cycles—and if I'd gotten the intuitive feeling, early enough, I think I might be quite a different person today. But as it is, I have to strain to manage the hardware aspects of, say, computers. And I'm sure there's nothing unstraightforward about it. I dig it when I read about it, but I just don't carry it in my mind. It may be partly the language facility. I just don't really get foreign languages very well. I have trouble with pronunciation, vocabulary, I have a bad memory and all that. I'm just not built for things like that. And for this work you have to be able to store away things verbatim and haul them out again. But I always have to look up, "What's the word for add?" or something like that, you know, every time, again. Or, I can write down a page of algebra—I go through, being careful not to make any mistakes, but then when I get all through, I want to check. And so I go through the page of algebra, that took me half an hour, say, to do, I go back to the top, and I canít recall having done it, from this step to that step. I did it, and there it is, and it's right, but I can't recall having done it. It's a funny thing. That way, I can pull things out of the file right now that I did a month ago, and I have to read them over again, and in a way, re-derive the whole thing.

DeVorkin:

Do you feel funny about that? Is there any feeling of insecurity, not sure what you're doing?

Leighton:

Well, while Iím doing it, I'm following out a logical procedure. I have problems, as for example, the deflection analysis for the 10-meter radio dish, and I have to do the job right because we have to turn 99 screws on the structure to correct the shape from the zenith to 45 degrees elevation, because there's a certain sag that doesn't go to a parabolic shape. So I have to know, down to a fraction of a thousandth of an inch, what the difference is between those two conditions.

DeVorkin:

Of a thousandth of an inch?

Leighton:

Say a ten-thousandth; say a couple of microns. And we're now down to a level of about a thousandth of an inch r.m.s. on it, but I have to worry about things of that order of magnitude. And so Iím worried about whether my algorithm on this is really right, and am I analyzing it right. So I just have to do it over again, practically, every time. I forget my structure and I don't document things. I've never been any good at writing things in notebooks, and having the sense to write down the important things. I'll start writing a diary or something. And then, sooner or later I realize that I'm telling about how we went up to Owens Valley on such and such a date, but I'm not telling what were the important things. Later I wonder: Well, what the hell was the size of the thing I measured? I didn't write that down. If I wrote it down, it's on a piece of paper and it's in my files somewhere, you know. I'm really very bad at that. I'm never going to improve, I'm sure.

DeVorkin:

Well, you seem to be making some interesting machinery. OK, so you got into the solid state work, of vibrational modes of a 1attice,[5] and you had made a plaster of Paris model to describe this, or to be able to actually make the measurements. I'm very fascinated with that. Is this a standard procedure?

Leighton:

Not at all. Although only last month, I met a chemist who actually had read my paper, and had considered using that approach to analyze a frequency spectrum of some polymer that he was interested in at one time, because it was a messy thing, and it seemed maybe the most direct way to do it, by just a sort of analogue. Now, I was concerned at the time with solving a problem, because I had to get a thesis. But also there were some experimental data, at low temperatures, for specific heat, and maybe some other things which had some discrepancies, with respect to the then current Debye theory, which was a rough approach, you know, to this whole thing. And the question was, to what extent the difference between the Debye quadratic frequency spectrum and the actual frequency spectrum of the modes of the solid, were responsible for this. So I endeavored to solve the lattice equations for a lattice of the same type as that for which there was experimental data, and this was a new kind of a lattice, a good project for a thesis. I didn't break new ground in the mathematics, certainly. But I believe to this day that what I did at the time was a better way to solve that particular problem, than to try to make some mathematical approximations by Monte Carlo or something, to try to sample the spectrum. And it was a little too early to be doing it by sheer numerical integration, of course.

DeVorkin:

Too early for from the standpoint of computers?

Leighton:

For the computers and things, yes. Today you'd never do it that way. There was one method I always wanted to develop further. I did it partly at the time, and except for one little thing which escaped me at the time, it would have been maybe a better way to do it. And that was through the use of an expansion of orthogonal polynomials. Eliott Montroll, who's now at Rochester, had published, with somebody else, a method of using the trace-moment theorem, where you expand the characteristic matrix to find the various moments of the spectrum.

DeVorkin:

You were talking about your thesis.

Leighton:

Yes. Well, I was just saying that there was a better way to do it, and that would be by orthogonal polynomials, and as often one does, you spend the rest of your life solving and re-solving your thesis problem, and I see how to do it very nicely now, with orthogonal polynomials, where I generate the polynomials myself. And that was the one thing I later felt I could criticize Montroll on, because he didn't take account of how the spectrum comes in at zero frequency. And if you just used the right weight function, which looked like the spectrum at each end, where you can tell what the shape is, then the polynomials you would get would be much more powerful in actually determining whether it's high at this end or that end, but it would give you the right start and the right finish. And I often thought that if I'd just used a little bit more brain power on that, I could have made a very nice contribution, and people would still be doing it, instead of carving the damn thing out of plaster of Paris. (Laughter) But I got better accuracy that way at the time, a couple of percent say. And indeed, it proved just what the experiment showed.

DeVorkin:

Do these models still exist?

Leighton:

No. They're gone a long time ago.

DeVorkin:

Any pictures of them?

Leighton:

No, I don't think so. I think in my thesis, there are the tracings of the surfaces. But I didn't ever take pictures of them.

DeVorkin:

It's an interesting first, anyway. How did the idea occur to you, to do this modeling? Model modeling, actually?

Leighton:

The problem was that the frequency space was filled with surfaces of constant frequency. This was the reciprocal lattice space. And because of the fact that I was using a cubic crystal, there was a high degree of symmetry, and I figured out what these surfaces looked like. I knew what the traces were on these symmetry planes, and the symmetry planes only filled up about 1/16 or less of the total space around a point, and then you could get everything else by symmetry from that. And it occurred to me that I also knew that the frequency surfaces met at right angles, and so if I knew my contours and knew how to start out, there wasn't very far you could go wrong, by just shaving it off. So actually, I modeled only on a very small solid angle, by going into the machine shop and using up a lot of expensive brass to make a mold. I then cast the plaster of Paris in blocks and then enscribed these contours on the outside, and sawed it up, and then carved each little piece out, so I could set it back in place, and cast in the pieces that were missing—I'd have all of them. It was just an empirical way to proceed. But that also really convinced me, I was not a theoretician.

DeVorkin:

How about other people around here?

Leighton:

Well, I think they knew it already!

DeVorkin:

How did they feel, your advisor, at least, when he realized you were going to make this mechanical model?

Leighton:

Well, the advisor who inherited me was old Paul Epstein. P.S. Epstein. He was a grand fellow, but I got off on the wrong foot with him, in a number of ways. And he didn't really supervise me at all. I did all this, and got a result, wrote it up, gave him the thesis. I gave it to him in draft and he handed it back, with the first chapter corrected as to English. And they were good corrections. He was a guy who could speak any language—with an accent. He was born in Russia, raised in Germany, and he learned English and so forth. Every language, he could speak, but with an accent. But he knew his languages, and so he really helped me on the language part. But he didn't read the thing until time for the exam. And he handed it back to me, and he said, "Ja, that is a very nice job. I would like to read it—some time." He probably never knew that I made a plaster of Paris model!

DeVorkin:

You were examined then. You took a defense on your thesis.

Leighton:

Yes.

DeVorkin:

Who was on the examination committee?

Leighton:

Epstein, Carl Anderson? Iím not sure. Smythe, Leverett Davis, he was on the rocket project, and he took Zwickyís place, thank God.

DeVorkin:

On the committee?

Leighton:

On the examining committee.

DeVorkin:

Why was Zwicky replaced?

Leighton:

I guess he just had other things to do. And he was interested in the supernova search at the time.

DeVorkin:

You said, "Thank God."

Leighton:

Well, yes, because Zwicky is so unpredictable. Really mercurial. I came to really appreciate Zwicky, and I was friendly with him, but he was a real madman. You know. Beautiful madman, but nonetheless with terrible problems with paranoia and things like that.

DeVorkin:

You didn't know him at that time?

Leighton:

No, I took a course from him when I was in graduate work. And so it was for that course, analytical mechanics, that he was the traditional person to ask people about it. But Davis was then a young staff member at the time. I guess that was his first oral exam, as a professor, my first one as a student. So he was as scared as I was. And it worked out just fine. I remember those three. Oh, and Morgan Ward, the mathematician, was on it.

DeVorkin:

Well, did they ask you about your modeling technique?

Leighton:

No. Not at all. At that time, the oral exam was almost entirely on general subject matter—e1ectricity, analytical mechanics, mathematics. There's a Bone Book around, if you want to look up and see what my reactions were, you can find me in 1947, I guess.

DeVorkin:

Bone Book? In other words, you would write in your impressions?

Leighton:

Yes.

DeVorkin:

Where are these books kept?

Leighton:

Judy Goodstein is the current custodian. I had them for a long time and didn't know it. These books were passed from student to student. And each student, when he takes his oral exam, enters his impressions.

DeVorkin:

Well, that's a very interesting record.

Leighton:

Oh, yes!

DeVorkin:

It's called the "Bone Book"?

Leighton:

Yes. You'll find me in it, both as the target and later as the fellow asking the questions.

DeVorkin:

Now, did everyone taking his orals in physics write in the book?

Leighton:

In physics. Yes.

DeVorkin:

Not in astronomy.

Leighton:

No. There's probably some astronomy Bone Books also. Ask Judy. Ask her if you can page through the Bone Books.

DeVorkin:

Well, the main thing is to know of the existence of this interesting document.

Leighton:

Yes.

DeVorkin:

OK. You said you had a number of different offers—Rice, and Hughes, and that sort of thing.

Leighton:

Yes.

DeVorkin:

But you elected to stay here, in 1947.

Leighton:

Yes. And that was at Carl Andersonís invitation. Aside from the war years, when I became very friendly with Carl, or vice versa I guess is the right way to put it—that was the first concrete, independent, new job, you know, that I'd ever taken.

DeVorkin:

What was the nature of the job?

Leighton:

It was a research fellowship in cosmic rays.

DeVorkin:

In cosmic rays. Had you been interested in getting into that, or was it the fact that the position was open?

Leighton:

Well, it wasn't either thing. There wasn't a position that was open. Carl knew I was there, and I guess he liked what he saw. And he needed somebody. I guess there was a position there or something. He knew that he needed somebody, but he didnít have a position, really, in those days. But there were fellowships, and so, he would keep asking me what my plans were. As I say, he didn't like to tell anyone what to do. I was not his student, but anyway, his office was there and I'd stop in and talk about what I was doing and everything, and held say, "Well, what are your plans?"

DeVorkin:

Where was his office?

Leighton:

He was down in Bridge Lab, in a certain corner, 101 Bridge or something. I said, "Gee, I don't know. Iím thinking about Hughes, I got this offer from Rice..." So finally I tumbled to what I had to do, and I said, "Carl, what should my plans be?" He said, "Well, I think it would be nice if you got interested in cosmic rays."

DeVorkin:

Did you have to ask what they were?

Leighton:

Not quite. But I said, "Well, gee, Carl, you know, I don't know anything about cosmic rays." He said, "You don't? Nobody does. II

DeVorkin:

Right. Were you aware of Millikan's long work on cosmic rays?

Leighton:

I knew. Sure, I had a course from Anderson, indeed, on them. I didn't know a delta ray from a gamma ray, though, at the time.

[1]The Sun (Harvard Books)

[2]The Cal Tech tuition at that time was $3000 per year!

[3]Rev. Mod. Physics 20 (1948) p. 165

[4]Principles of Modern Physics (McGraw-Hill 1959).

[5]Op. cit. p. 18 (1948)

Session I | Session II