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Oral History Transcript — Dr. Bart J. Bok

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Interview with Dr. Bart J. Bok
By David DeVorkin
At Steward Observatory, Tucson, Arizona
May 15, 1978

open tab View abstract

Bart J. Bok, May 15, 1978

ABSTRACT: Interview discusses, not always in chronological order: early home life and schooling; undergraduate at Leyden, influence of Ehrenfest, Oort, Kapteyn, Kuiper, Pannekoek, Hertzsprung. Recollections of work of Uhlenbeck and Goudsmit. Assistant to van Rhijin at Groningen ca. 1928, work on various stellar and galactic topics. Move to Harvard, 1929, and atmosphere there under Shapley. Marriage to Priscilla Fairfield Bok; her contacts with W.W. Campbell. Search for and interpretation of spiral arms of our galaxy; studies of stellar density distribution. Activities during World War II. Harvard astronomy group's difficult postwar transition; McCarthyism. Work on nebulae and globules. Comments on astronmy at Mt. Wilson, Tonantziutla, and South Africa. Origins of Harvard radio astronomy and National Radio Astronomy Observatory, and their funding. Move to Australia, 1956, and conditions there. Move to Steward Observatory of University of Arizona, 1964, and conditions there. Location of national observatory at Kitt Peak; management of Kitt Peak. Discussions of astronomy, education, popularization, employment, and organization.

Transcript

Session I | Session II | Session III | Session IV

DeVorkin:

I'd like to have you recount your early home life, influences upon you that brought you into a career in science, and something about your family.

Bok:

I was born in Hoorn, Holland, on April 28, 1906. By the way, the house in which I was born is now a national monument. It has nothing to do with me. My father was a sergeant major in the Dutch Army, and he lived in military barracks. Those military barracks where I was born, were old packing houses of the Dutch East India Co. from the days of Jan Pieter Zoom Koen. These packing houses had been transformed into military barracks for people who weren't officers, but who were married and in the Dutch Army. I lived there until I was nine months old. I tell you how the place became a national monument. My grandfather was a carpenter, and my whole family sort of "fell upstairs," the way that sometimes goes. My uncle became quite a famous architect, and he was in charge of restoring and preserving old buildings. Then one day, in about 1936 or '37, he got an order from the Dutch government to tear down all these packing houses of Pieter Zoom Koen, there were 24 or so of them, but save two, and turn the two into national monuments. And my uncle said, "What the hell," and he made the place where I was born into a national monument! This is rather cheerful. It has nothing to do with me, but at least it was that family influence that got me born in a national monument. I was brought up in school in Haarlem, in the north near Amsterdam. And Haarlem was where my first interest came in astronomy, because I learned from my grandmother that my grandfather, who had also been a sergeant major in the army, had had a long interest in astronomy. He was in the technical service, where he did machine work for the navy, that sort of thing, and he had read a lot about Kirchhoff and Kirchhoff's laws. But the real thing began for me when I moved to the Hague.

DeVorkin:

When was that?

Bok:

I went to The Hague about 1918. Right after the end of the war. Holland was not involved in the war but my father was at the border all the time, and then at the end of the war, he was transferred to The Hague. And in The Hague I joined the Boy Scouts again, I'd been with them in Haarlem already, and then became sort of a big shot, a patrol leader. And one day they had an exam, and the Scout Master found that Bart Bok didn't know a single constellation, and he shamed me into learning them, for he said, "How can you be a patrol leader if you don't know your way around the heavens? What do you do with the poor boys in your patrol who say, what is that star, what's that star? If you don't know it you're a failure, and you have to put logs in their mouth to keep them quiet, and that's a sad thing, around the camp fire."

DeVorkin:

Did this man have a particular interest in astronomy?

Bok:

No. He was a geologist, but a very competent one.

DeVorkin:

What was his name?

Bok:

I've forgotten, but he was a geologist in Utrecht and quite a prominent one. So I learned my astronomy by myself, and that period was in high school. The Dutch high schools were excellent in those days. For example, I was in the city high school where the son of a sergeant major goes, no tuition, but two-thirds of the teachers in my high school had doctors' degrees. And while I was at the city high school, three of my teachers became professors in the university. That was in the old days. That's all over now. They had very difficult exams for us, very high standards. I remember that in each language you had to be prepared at the final exam to have a half hour oral exam, in the foreign language: French, German, English. You had to appear with a list of 20 books or poems that you had read, and could recite in part. And then there was a half hour discussion in the language by which you were judged. So the whole thing was a very high standard system, with very good science.

DeVorkin:

I was going to ask about the science.

Bok:

The science was fine. We had a new physics teacher. And I tell a story about him. Because he had fresh ideas. He's exactly ten years older than I am, and I was then about 15 or so, in the middle of high school, getting physics, and the physics teacher came fresh from Groningen University, and he was a typical Groninger, a very firm character. He and I have sort of remained in contact off and on. He now is retired in Groningen, from having had an ideal position as a high school teacher in The Hague. He was firm with the class, and said that the grades here will go from zero to 10. "Nobody is worth a 10. Nobody is worth a 9. Only I am worth an 8. You boys and girls start at 7." And that used to be his grading system, and his grades always looked low compared to all the others. I went back to Groningen two years ago to give a colloquium, and they made quite a fuss about it, you know. The astronomers got together, bought a bottle of sherry, and we had a fine party, and they invited my old high school teacher who was 83. And he came up and he looked smug and proud, you know. His local boy's made good. Then when the colloquium was over, here I was, 71 years old, and he came up and said, "Bart, that was a good colloquium -- 7 plus!" I've never been graded for a colloquium. And the plus was really as high as you can go. Only he was worth an 8. He hadn't lost his sense of humor, either.

DeVorkin:

What was his name?

Bok:

Dr. Mulders.

DeVorkin:

At the time when you were in high school science, can you recall the topics and treatment?

Bok:

Oh yes. We had cosmography, they used to call it, and I learned a great deal about astronomy there. That was the time when I became an admirer of Harlow Shapley, in the third or fourth grade of high school. Because in Holland, they had the great J. C. Kapteyn, and Kapteyn was anti-Shapley. But the amateurs in Holland thought Shapley had it made, especially a newspaperman named Easton, who had had some theories of the Milky Way, who abandoned his theories and said, "Shapley has got it."

DeVorkin:

He had spiral structure.

Bok:

Spiral structure centered in Cygnus. Yes. And Easton was quite a man. Anyhow, I read these magazines, and I wanted to have a subscription to the magazine Himmel und Dampkring (that means "The Heavens and the Sky"). I wanted to have a subscription, and I didn't have the money, so I went to a little regional Hague newspaper and said, "If you buy me a subscription, I'll write you an article free of charge every month." And I did. So I became a great Shapley enthusiast, long before I even was in the university.

DeVorkin:

Do you have these articles still?

Bok:

No. I throw things away. I'm a bad man when it comes to saving things. But they were articles about the center of the Milky Way, and that Kapteyn had gone wrong. Kapteyn wouldn't admit it. Kapteyn died in 1922, and never really admitted that Shapley was right. Everybody else did by then.

DeVorkin:

What's the name of the newspaper that you worked for?

Bok:

Bloemen Nen Boomen Kwartier. That is the section of The Hague where the flowers and the trees are. They used to call it the "Bloemen nen Boomen Kwartier." And the streets are all named after trees and flowers in that part.

DeVorkin:

Would this newspaper be in libraries in The Hague?

Bok:

It might very well be. Yes. By the way, I got very excited about Shapley when he published his debate with Curtis from the National Research Council. I wrote to the City of The Hague library and told them that no library in the world would be complete if they didn't have this critical volume. And the City of The Hague library bought a copy from the National Research Council. It probably is still there. So I became interested in it, and I wanted to go to the university and study astronomy.

DeVorkin:

What did your parents think of all this?

Bok:

My mother was very interested in it. My father was a bit dubious. My father had always hoped that I would become a high school teacher. When I was appointed to a full professorship at Harvard, my father said, "It's wonderful you are a full professor at Harvard. But to be perfectly frank, I had always hoped that my son could be a high school principal in The Hague." That shows the sort of way that things go. But my father was very proud and everything. My mother felt that her father, who had read all the astronomy at night, my grandfather, was vindicated by having his grandson be an astronomer. But he died in 1912, so he never knew about it.

DeVorkin:

Did he read astronomy to you?

Bok:

No. He had read astronomy to my mother when she was a little girl. He was an ardent reader and at night he would read his books and he would say to his wife and daughter, "Now, listen, here is what I do --." He explained Kirchhoff's laws to them, you know, and the Fraunhofer spectrum and all that. He was very interested in those things.

DeVorkin:

Were those books in your family? Were they available to you?

Bok:

Yes.

DeVorkin:

What books were they? Did you read them?

Bok:

Yes. Oh, I read them all. I've forgotten what the names of them were. They were books in part done by an old Dutchman named de Keyser. De Keyser was the director of the observatory in Leyden for quite a while, long before W. de Sitter. Then in The Hague there were always very good public lectures. For example, Minnaert, whom everybody knows of course, used to come twice a year to The Hague to give public lectures. And then also Ehrenfest, for example. I attended a course on atomic physics under Ehrenfest the year before graduating from high school. So we immediately had lots of access in really good up to date science, which was very nice.

DeVorkin:

What was it like? You were still a high school student then, when you heard Ehrenfest?

Bok:

Yes. When I first heard him, yes.

DeVorkin:

What was your feeling about him?

Bok:

Oh, I became an admirer of him. I have a few heroes. Shapley is my biggest hero. For example, when I joined the National Academy of Sciences, or was invited, one of the things you take as a sort of assignment is that you will write an obituary for somebody. Well, Shapley was still alive, and they tried to push some other obituaries or biographical notes on me, and I said, "No, I'm going to wait till Harlow dies. Then I will write his obit." Which I have done, of course. My second hero was Ehrenfest, no doubt about it, in physics. I'll come back to him in a moment. And the third one was Jan Oort. Jan Oort is exactly six years older than I am. He was a young man when I was at Leyden when he discovered galactic rotation. That was in part influenced by G. Kuiper and myself, who were his students at the time.

DeVorkin:

What influence?

Bok:

We influenced Oort to go to work on galactic rotation.

DeVorkin:

Oh, we must talk about that.

Bok:

We'll talk about that in a moment. We had a lot of fun just doing it. He lectured on B. Lindblaad's new work, and he got bogged down. He had no lectures for two or three weeks saying, "I'm bogged down." And then he came and said, "I have a very simple solution, much simpler. Lindblaad worked all in differential geometry, complicated mathematics -- and here's the way it should work --" and he got the simple principles of galactic rotation started. W. de Sitter was the director at Leyden, and I liked de Sitter, but he has never had a particle of influence on me. And Ejnar Hertzsprung was the second professor at Leyden. But I was frankly scared of Hertzsprung, very scared, because Hertzsprung wanted to have all budding astronomers observe variable stars by giving them 200 plates and let them discover 20 or 30, and he felt everybody ought to go through that. And I had no intention of becoming a variable star measurer from photographic plates. So when I saw Hertzsprung, I went the other way as much as I could.

DeVorkin:

Let's talk about your going to Leyden. Was there any question that you would go to Leyden or some other university?

Bok:

No. I wanted to go to Leyden, but it looked financially impossible. And that is where the city examinations in The Hague came in handy, because in the year when I went to Leyden, in 1924, the city of The Hague for the first time offered five scholarships, that paid the amount of 1000 guilders a year, which was then a large fellowship. And the city of The Hague went by recommendations very much from the co-examiners on the oral exams. I had good physicists and mathematicians, not overly good as teachers. But I had a historian who is one of the famous ones, Dr. Japikse, who was on this board for the fellow ships. And he said to the city, "I've got a boy you ought to send." Then I got as an advisor (this is for the son of a sergeant major from public high school in The Hague) the famous designer who built the Zeider Zee -- Haupt Minister Lely, and he became my advisor. So the city of The Hague looks after its little children very well indeed.

DeVorkin:

Fascinating. In other words, you had advisors in the community.

Bok:

In the community.

DeVorkin:

For your university career.

Bok:

For my university career. And I had to have tea with him about five times a year. In other words, I saw more of Lely than most Harvard freshmen see of their freshmen advisors. That was a very nice thing. And he kept, right to the end of his life, a great interest in me, and kept on advising. Anyhow, I was then in Leyden. And Leyden was a wonderful place, because people like Schroedinger and Heisenberg and, of course, Franck especially all came to Leyden whenever they had something new, to talk it over with Ehrenfest. Ehrenfest of course was recognized as the great critic among the physicists. Dirac used to come there. I never saw in Leyden Rutherford, but in the early days, for example, people like Madame Curie came. Leyden was a very fine center. Lorentz had retired, and Kamerlingh-Onnes almost retired the first year that I came to Leyden. So then in physics, in practical physics, the one who had the most effect on me was de Haas, who was married to the daughter of Lorentz, and was very good in magnetism and things like that. But Ehrenfest is the one who influenced us a great deal. First of all, it's interesting to know, there is a great class, what we call the Class of 1906 in astronomy, of astronomers who are now either dead or dying, or old like me. They all were born in 1906. And how this happened is a very interesting thing. World War I upset everything. Then after World War I, there came a feeling that the end of all wars had come, and that it was all over. For example, I remember discussions about entering the Dutch Army, which we had to do, and I went only on a summer basis. Kuiper said, "That's the silliest waste of time I've ever heard of."

DeVorkin:

You spent summers in service?

Bok:

Yes. I did.

DeVorkin:

While you were at Leyden?

Bok:

At Leyden, yes. And Kuiper, instead, decided to postpone it for two years and take a full year as he said in 1925 to a group of us talking about this, Gorter was one among the students he later was the head of the Kamerlingh-Onnes Lab who has done all the low--temperature work -- and who came very close to a Nobel Prize when Rabi got it instead, a very famous low temperature man). Well, there was a group of these budding young physicists and astronomers all together there, and Gerard Kuiper was with me. He was the first one I met when I came to Leyden. And Ehrenfest heard that there was this bunch of bright little high school boys that had suddenly come to Leyden. In the past at Leyden there had been only about one student of physics a year or something like that, and suddenly there were seven or eight of us. And Ehrenfest said, "You little boys and girls, mathematics students and otherwise involved, you are in the saddest university you could have come to learn theoretical physics. Because if you want to take a course in theoretical physics, the first prerequisite is that you must take a course in mechanics from a mathematician the year before. Before you can take the course in mechanics, you must have had a course in differential geometry, differential equations, that's another two years. Before you can take the course in differential equations, you have to take two years of calculus and theory of functions." "Therefore," said Ehrenfest, "it's very simple -- all of you will be old men by the time you begin to think about theoretical physics. So," he said, "you don't know calculus yet -- I'm going to teach a course in which I use it freely, and I'll give you a course in beginning physics, theoretical physics." And what he did, in our first year, while we were also learning the calculus, he took us from the beginning to the end of Courant-Hilbert, Volume I. And that was a great thing. Every Tuesday afternoon. And then when the vibrating string came, he said, "Now there is a little trouble. These are not going to be straight, they make them now crooked, these, that means, not too damn many of these walking around there..." We got it all straightened out, and we went all through Courant- Hilbert in our first year at Leyden University, while we were also taking beginning calculus. And that of course had another advantage -- we got to know Ehrenfest very well. And Ehrenfest always set high tasks. At the beginning of my second year, 1925, Eddington's Internal Constitution came out. [1] Eddington's Internal Constitution was already famous before it came out. Internal Constitution of the Stars (Cambridge, 1926). Ehrenfest had this famous colloquium you may have heard about, the Ehrenfest colloquium, in the early days, and he said to me, "Bart, we've got to find out about Eddington's book. I'll give you three weeks to read it, and then you give a colloquium."

DeVorkin:

Three weeks?!

Bok:

I was second year, only. So that was it. Then, the evening came, and that evening there were two Nobel Prize winners in the audience. I think Kramers was a Nobel Prize winner by then. Kramers and Koster, who had discovered Hafnium. Kramers and Koster were both there. And then when the colloquium was about to start, the first thing that happened was, Ehrenfest said, "There is a visitor here from England, who cannot understand Dutch. Will you give your colloquium in English?" I had never been to England. I only had high school English, but there you were with Ehrenfest, you knew where these orders came from. So I started off my colloquium. Before the colloquium started, Kramers, who was a snooty, arrogant but wonderful man, got up. Arrogant like anything and always liked to put little boys in their place. Kramers got up and said, "To begin with, before this young man gets under way," he said to Ehrenfest, "I would like to say one thing. I see no reason why stars should be hot inside. They're cold inside. If Mr. Bok knows a single reason why stars should be hot, will he please explain it to me?" That was the beginning of the colloquium -- which was a rather difficult beginning. Then Koster, who also felt his oats, came along, and I started talking about magnitudes, and the mass-luminosity relation, which I thought was critical. And Koster couldn't understand it at all. Finally Koster said, "Oh God, these astronomers are silly people. When a star gets fainter, it gets a bigger number; when it's brighter, it gets a negative number. Oh my God what a silly bunch you are!"

DeVorkin:

Was he serious?

Bok:

Well, they had a fine time, razzing a young little boy, who was boosted by Ehrenfest. But it worked out very nicely. We had a cheerful evening, went through Eddington's Internal Constitution in English. They were the sorts of things you got thrown at you when you were in Leyden. It was very good to have the contacts with that whole group of people, right when we came in.

DeVorkin:

Who was the English visitor? Was he of any consequence?

Bok:

No, no. He was a South African named Wood. He had been in South Africa. But he was of no consequence. So if it had been necessary, he could have been ignored. But Ehrenfest always tried to put you ahead of where you were, that was part of his whole idea -- he was a master in doing these tricks.

DeVorkin:

Eddington's book, toward the end, pretty much decides that the Russell theory of evolution of stars is pretty much untenable.

Bok:

Yes.

DeVorkin:

Especially because of the mass-luminosity relationship.

Bok:

That's right.

DeVorkin:

Did you talk about these things?

Bok:

Yes, a little bit. They came in all right. Oh, yes, during the question period, but I'm a little vague about all that went on. For example, Oort wasn't there. So the astronomers were not there. I talked primarily to a group of physicists, who wanted to know how the stars were constructed: how pressure and how energy generation happened, and in a way, Eddington did come out against the Helmholtz contraction theory, and talks of what now looks like atomic energy. So it was a very interesting book to review, and very good for me to read, of course.

DeVorkin:

The physicists there, did they discuss or speculate about synthesis at that time?

Bok:

Very little. It was very little, at that time. Not that I remember at this moment. That came later. That came more towards the end. The synthesis didn't really come in, in a major way, until Bethe. But there were some early discussions of it.

DeVorkin:

In the late twenties, proton synthesis?

Bok:

That's right, and there was some work by Houtermanns and Atkinson. Those two. But that was not discussed on the night I was there. It was mostly a general review. Kramers' question was a good one, they really wanted to know, how the hell does a star stay at one size? Why doesn't it collapse? Why doesn't it vibrate? If it oscillates, why does it oscillate back and forth, the Cepheid sort of picture? The equilibrium problem interested the group the most. What were the equations of condition, basically? And what were the limiting integrals that you had -- mass, luminosity, radius, and how did they all fit together?

DeVorkin:

Did Kramers discuss applications of quantum mechanics to determine opacities?

Bok:

Yes. That Kramers had many questions about. And of course the Kramers Limit was by then quite well known already. Kramers came in mostly on the effects of opacity that evening. And, in a way, that led to the whole thing of how the stellar layers were built on top of each other. But the interesting thing is that a young boy of 19, just out of high school, under Ehrenfest, is getting this sort of an assignment. And brother, you'd better make good, for if you fail, Ehrenrest wants nothing more to do with you. That's all there is to it. He was very friendly, up to a point. Up to a point. He wasn't going to waste his time. He had a very interesting advisor, by the way.

DeVorkin:

Ehrenfest did?

Bok:

Yes. His principal advisor, on all mathematical and astronomical affairs, was the father of L. Woltjier, Jan Woltjier. Practically no one in the world knows how great a man Jan Woltjier was. Because when Heisenberg or Schroedinger would come, then Ehrenfest would say, "You spend the day with Jan Woltjier. If he says it's OK, I'll talk to you." That's the way he did it. And Jan Woltjier, for example, is one who had strength in the astrophysical community at the time. His son didn't even know this, two years ago when I mentioned it to him. Jan Woltjier was invited by the British magazine Observatory to write the review of Eddington's Internal Constitution of the Stars. Everybody was wondering, when that famous book came out, who would be asked to review it? Was it E. Milne, or who would do this? You know, one of the top men. And they picked Jan Woltjier as the one for it. He did more for Kuiper, Osterhoff and me, to introduce us to the beginnings of astronomy and astrophysics, than anybody else. Another man who had a lot of influence on me, purely accidental, and who became a very close friend, was Arthur Milne, who came later on, when I was in Groningen for a colloquium there, and he and I argued abundances of hydrogen, and how the fact that there was hydrogen high up in the atmosphere proved that there must be a hell of a lot of hydrogen in the rest of the sun. We were very close to practically having the Russell principle. So Milne was a close friend of mine.

DeVorkin:

That's an interesting interest for Milne. He was a very, very strongly mathematical person, and yet he did try to do some physical thinking.

Bok:

Oh, he was a great physical thinker, too. His own family thought of him as the man who had really done relativity, and had a different approach to the whole universe. That was a little detail of the latter day Milne. But Milne was in the early days a good eclipse observer, and Milne wrote papers on the nature of the chromosphere, of the corona, and the photosphere of the sun -- transfer of radiation. He was a top man in that. And Eddington liked Milne very much. Jeans hated Milne, as he hated Eddington, too. So that was sort of the beginning of my physics in Leyden. I had good mathematics teachers, but nothing great. But in astronomy of course, there was Oort and de Sitter and E. Hertzsprung. I had small courses from all of them. And the ones by Oort made by far the greatest impression, for Oort was then lecturing on the new theory of galactic rotation of Bertil Lindblaad, which was then considered the real great thing, because it explained the asymmetry of stellar motions. And that was really the thing that started it off. Lindblaad himself had set up this rotational principle, but he had made it so complicated, full of differential geometry and oscillating planes, it was hellishly complicated to read. He never thought of the simple Oort formulae sort of thing.

DeVorkin:

Relating it to observables?

Bok:

The simple observables, you know. And then Oort was lecturing on it to us, to Kuiper, Osterhoff and me, and maybe one other person, maybe Duram was there, who's been dead for many years. Anyhow, he was lecturing to three or four of us, and Oort got bogged down in Lindblaad's figures. Then he began to draw the simple diagrams for differential rotation. And got the sin (21) formula out of that, for the radial velocity.

DeVorkin:

He drew the diagrams?

Bok:

Yes.

DeVorkin:

But what was your stimulus?

Bok:

We kept on asking nasty questions of Jan Oort. Every time. We were trying to understand it. He said, "I'll figure it out better -- just take it easy, boys, take it easy, we'll come back next week." He had one lecture a week, Monday afternoon at 4. "OK," he said, "come back later, then we'll see how it goes." And then, for two or three weeks there was nothing. And then he came and he said, "I had an awful lot of trouble, but I think I have a very simple approach to it. It looks almost silly." Then he produced the sin (21) formula. And then, when he wrote it up in his paper, in B.A.N. 120, Oort started off by saying, "It can readily be shown that the radial velocity effect is R times A times the sin (21) minus 1." you know. So then, Oort came out then and lectured on this. And then, I talked with Oort. We had a small group, which was a very nice way to have lectures, and I said, "If you have the differential rotation, Jan Oort, don't you think that there should be a shearing effect, that tears galactic clusters to pieces?" And Oort said to me, "That's a very good topic for later research, Bart. Why don't you look into it? And if I were you, I'd begin it by studying disintegration of comets, because in a way the comet approach is the same." And you know, I wrote Harvard Circular (H.C.) 384 about three years later,[2] and when I thanked Oort for having suggested the topic to me, he wrote back and said, "I didn't do this. It never occurred to me." But at least it was his idea. This was 1934 in "The Stability of Moving Clusters." And Oort was the one who suggested I go into that. And then I thought for a long time, either he or Lindblaad will probably do it. But they didn't and nobody did, so then I got involved in it, and did it at Harvard.

DeVorkin:

Well, once Oort worked up the observables, and the A and B Co-efficients, there was quite a while when he was very concerned with establishing just what the values were.

Bok:

Yes.

DeVorkin:

So I guess he was working on the overall problem, things that we'll call turbulence.

Bok:

Yes, that's right. He was very deeply involved in the whole thing. He was also deeply involved in high latitude studies, and the two of them were both sort of interchangeable and all-consuming interests, at one time. He was a wonderful man to be with of course, at that time. Exceedingly active. Still is.

DeVorkin:

There are two questions that come to mind, that are not too closely related but certainly we want to get through them. One is that you were experiencing a very vital physics environment. Quantum mechanics was just growing at that time.

Bok:

Yes. Beginning, yes.

DeVorkin:

Ehrenfest must have been incredibly exciting. And on the other hand, you were tasting the fruits let's say of Kapteyn's tremendous work, in the establishment of galactic studies.

Bok:

Yes.

DeVorkin:

Was there any question in your mind as to which direction you were going to go?

Bok:

No! No, I was from the beginning an enthusiast for Shapley and Oort. And Ehrenfest never tried to convince either Kuiper or me that we should get away from astronomy. Ehrenfest never said, "Oh, you ought to get out of this silly astronomical -- " Oh no. He knew we were marked astronomers, and were proud to be astronomers. Then there were people like Groter in physics and quite a few other physicists in what was in a way the period of the beginning of the decline, you might say, of Dutch physics. The Nobel Prize quality began to disappear from Holland at that time.

DeVorkin:

Was there a reason for that? Do you know?

Bok:

I think probably that Lorentz and Kamerlingh-Onnes were such powerful cusses. But for example, in astronomy, I think we all derived from Kapteyn. It all starts with Kapteyn. Oort was Kapteyn's student. I was Oort's student. I was van Rhijn's student; van Rhijn was Kapteyn's. Pannekoek was a great friend of Kapteyn's. So the rise of Dutch astronomy was entirely Kapteyn, and pupils inspired (by him), and I was sort of given the feeling by Oort and by van Rhijn that it was my job, when I came to the United States, to carry on the banner. And that's probably why I had 55 Ph.D.'s to my credit. Yes, it's quite a number. B. B. Lynds made a list of them once, when they had a farewell symposium for me, as director of the observatory. And at that time, B. B. Lynds made the list up and I helped, and we had 55 on the list. That's quite a number, you know. That's quite a gang.

DeVorkin:

That's marvelous.

Bok:

And they have all done pretty well, you know. David Heeschen is one of them. Jesse Greenstein was one of my early ones. Sid McCuskey is one of mine. So I have a whole lot of old men. Lots of them. But that comes, I think, from the Dutch penchant to support the strong person who inspires people to go on and preach on the Milky Way. Kapteyn was a strong one, in that. He hated the guts of Shapley. He disliked the man most thoroughly.

DeVorkin:

What kind of a position did that put you in? Because you were an early spokesman for Shapley.

Bok:

Kapteyn was dead in '22. And I started in Leyden in '24. So Kapteyn never knew I existed.

DeVorkin:

But you'd written these newspaper articles on Shapley's work.

Bok:

Yes, but he didn't read those. It was a small little local town newspaper, and I wrote the articles only because I wanted to have a subscription to the magazine. I didn't have the money to subscribe to it and be a member.

DeVorkin:

Was Oort outspoken, during any part of this?

Bok:

Oort was very outspoken. But Oort was an admirer of Shapley, too. Originally Oort wrote his doctoral thesis under P. J. van Rhijn basically, because Kapteyn died too early. Oort wrote his thesis on high velocity stars, and gave this beautiful Groningen Publication 40, which was quite a thing to bring out. Oort must have had problems about Shapley with Kapteyn, but I've never heard him talk about that. Oort talks very little about his relations with Kapteyn. And Oort was still reasonably young when Kapteyn died. You see, he was born in 1900, so he was 22 when Kapteyn died. Kapteyn liked him and admired him, he and Jan Shilt -- the one who ran Columbia astronomy -- of course were very close friends. But Shilt was definitely second rate compared to Oort, no doubt about it. His things have never stood up, you know, and by now nobody knows any more that he existed.

DeVorkin:

I know where he lives. We were trying to contact him. Was he a contemporary of Oort's?

Bok:

Yes. But he had been an officer in the Dutch Army during World War I. He was I think about three or four years older than Jan Oort.

DeVorkin:

I know of Shilt's work at Columbia.

Bok:

Yes. He was at Yale first, of course. Oh yes, Schlesinger was a great friend of his.

DeVorkin:

Why did you leave Leyden?

Bok:

That's where Mr. Lely came in. They had in those days very few assistantships or fellowships in astronomy. I had the fellowship from the city of The Hague, so I was well off. But van Rhijn needed an assistant. In Leyden, de Sitter had two assistantships, but they split the money for it into three; for two that would have paid each a thousand, therefore each of the three got 666 guilders a year, so they were very small. Kuiper had one of those. So there were a few at Leyden. So van Rhijn at Groningen had the only full time assistantship -- Utrecht in those days didn't count for much. Nobody wanted to go there. Pannekoek was only a bright privatdozent in Amsterdam. Pannekoek, of course, was basically a mixture of a very good astronomer and astrophysicist, and one of the best Communists in the world. I hope you know this.

DeVorkin:

No, I didn't know.

Bok:

Oh, Pannekoek used to have debates with Lenin. Lenin used to write polemical articles against the Communistic theories of Pannekoek which were not kosher Communism. Oh, Pannekoek and Lenin were adversaries, you might say, but both very strong Communists. And when I told my father I wanted to go into astronomy, my father (the sergeant major) said that was a dangerous field, with this Communist Pannekoek in it, "I wouldn't take that field, that's not a good field for young men to go into."

DeVorkin:

Is that one possible reason why he didn't have students or a large department?

Bok:

Yes. Yes. Otherwise he would have had. But he was very deeply involved during the Russian Revolution, and in some of Lenin's books, there are five or ten pages against Pannekoek's approach to Communism.

DeVorkin:

Is there anything of his political feelings in his History of Astronomy,[3] that you know of?

Bok:

Yes. Quite a bit. Quite a bit. And the history of astronomy is well worth writing. I don't know if you know how it got translated into English?

DeVorkin:

No.

Bok:

Pannekoek had written it in Dutch. He had made an English translation, and offered it for publication to the University of Chicago Press. And Kuiper decided against it. He was then the advisor on these things, and he said, "No, don't publish that book. It's a silly book. It's written from a political point of view and will only get you in trouble, forget about it." Pannekoek had rather poor English. My wife Priscilla got so worked up about it, that she took Pannekoek's book and wrote it in English. Then the book got published.

DeVorkin:

That's fascinating.

Bok:

That book caused quite a stir. Kuiper tried to stop it at Yerkes Observatory. He was then the big shot, and said, "No, that book is silly, it has no value whatsoever."

DeVorkin:

Has it also caused Pannekoek's early work to be ignored? I guess in the first few years of the century he had done some statistical work which was not that different from Hertzsprung?

Bok:

Yes.

DeVorkin:

No one has ever followed that work up?

Bok:

No. No.

DeVorkin:

Is there a reason for that?

Bok:

No, I don't know. I don't know about that part. I got interested in Pannekoek through the dark nebulae, because I became interested very early in dark nebulae and there were a few people who have really done valuable work, apart from Max Wolf who had done the original thing; Barnard who had listed the Barnard objects, then there was Pannekoek, who had written some very good articles for the Netherlands Academy on them, and Malmquist in Sweden. They were the four. And I got in that business, over the dead body of van Rhijn, who said, "You ought to stay away from these things -- the distribution of the stars in space, you give far too much room to dark nebulae, they're a nuisance. If you want to get the properties of the Milky Way, certainly you must avoid them, and all you have to do is avoid dark nebulae, don't pay any attention to them." Van Rhijn was a pure [???]. He believed absolutely in a uniform galactic system, that somehow would be determined by a couple of Gaussian equations, and there you would say, "This is the Milky Way system." And van Rhijn didn't believe in absorption effects, and then when these annoying things happened, you had to avoid them. When I wrote my thesis, on n Carina, van Rhijn at first refused to give me a doctor's degree on it because, he said, "It's only one silly region in the sky, it's the sort of thing that that man Pannekoek would do. Listen, Bart, -- that is not astronomy. You have to have it for 24 regions, distributed equally in galactic longitude. Then you will find out what you are doing. But your way will never do any good -- this approach of a single region -- it's just plain silly." Van Rhijn did not believe in spiral structure. There was no evidence for it that was anything. And then he was very down on Pannekoek, because you had to determine distances by statistical methods, like Kapteyn had used them. They worked, of course, for the luminosity function beautifully. But van Rhijn was sure that the whole structure of the Milky Way would somehow grow out of that.

DeVorkin:

Well, he was a student of Kapteyn's.

Bok:

-- of Kapteyn's. He was Kapteyn's favorite student, you might say.

DeVorkin:

Kapteyn spent his whole career looking for general absorption.

Bok:

Yes.

DeVorkin:

And was always convinced that it was there.

Bok:

In some ways, but van Rhijn said, "Kapteyn has proved there is none." Yes. And then de Sitter did some early work in his thesis -- for he was Kapteyn's student too -- on color effects, and found no color effects with very poor color indices. And therefore, van Rhijn says, "There's no such thing as absorption."

DeVorkin:

I see, after all that work.

Bok:

In the end, van Rhijn was very good friends with Shapley, and he always told me, he didn't dare to tell Kapteyn how he thought Shapley was right, but that he thought Shapley had been right about the general structure of the Milky Way system. And then van Rhijn kept on saying, "But there is a local system as well, in which we live, and that local system can only be investigated properly by the techniques of Kapteyn."

DeVorkin:

Well, it's certainly true in terms of really getting at that local system.

Bok:

Yes.

DeVorkin:

And that's what you had done, you did that through the thirties and forties?

Bok:

Well, then I wrote a paper, Harvard Circular 371 in my early days at Harvard, on the interpretation of star counts and interstellar absorption and there I used Kapteyn's n log table for the first time. Kapteyn had never published that n log table but only used it in his introductory lectures on stellar statistics, to show little boys and girls what actually went on. But Kapteyn said, "It is below my dignity to ever publish that." So do you know where I found it? Kapteyn had once a renegade student named Schouten, who became a high school teacher, and who apparently was a very difficult person. I never knew him. But Schouten had a dissertation which Kapteyn refused to have published as a Groningen publication, which Kapteyn didn't even want to have published, and Schouten published it privately. I had a copy of it at one time. And Schouten in there reproduced Kapteyn's simple n log table, and then I began to look at it in 1931 or thereabouts, and said, "Jeepers Creepers, it's simple, that is the way to look at the Milky Way, let the things talk for themselves -- put your luminosity function in, put your density function in, and apply it to high latitudes and other things." But van Rhijn thought this was just the silliest thing I could do. He said, "There is no decent mathematics in there. There are no Gaussian functions in it or anything like that. That's just plain silly." And then van Rhijn has another limitation: he never understood the Malmquist correction. He had a block against the Malmquist correction. So in a way, van Rhijn was really [???]. He just had strong feelings, and his major thing, of course, was the van Rhijn luminosity function, which he did beautifully.

DeVorkin:

I notice in that paper on the analysis of the star counts, you come right out and say that the early attempts to describe the galaxy by these analytic functions is just not possible.

Bok:

Yes, and that made van Rhijn furious. So van Rhijn practically, for a while -- when I came with the finished n Carimae thesis and had done the analysis of star counts, I thought I had earned a doctor's degree. That was the beginnings of the stability of clusters. Van Rhijn said, "These are all silly approaches to a dignified problem. Only this man Pannekoek would do these sort of things. Sometimes," he said, "I have read in one of your papers, you do just what Pannekoek does. You say, 'Assume that the B 2 Supergiant has an absolute magnitude minus 5.' My God, man, you've got to prove that -- and the only way you prove it is by proper motion, radial velocity, analysis -- so, there isn't a solar motion solution in your thesis at all," he said. "That just is not the way to do it. This is like this fool Pannekoek does." So van Rhijn was very difficult. Then in the end, it got so far that I said to him, "Listen, I'm going back to Harvard. Harlow Shapley will give me a degree in ten minutes." I said, "I'll go back and do it there." Then he said, "Well, let's sit down, Bart. We like each other. We get along all right. OK, I'll give you the degree." Then I got the doctorate from van Rhijn, but they gave the generalist degree. It would have given me satisfaction to have: "I had the honor," or "I gave you cum laude or summa cum laude" -- but mine was: "You are hereby awarded the degree of doctor." That was the only thing I got. And then, half a year later, I had a postcard from van Rhijn, a little postcard -- just a small little penny postcard -- and on that one he said: "Dear Bart, I am glad that after all you got the doctorate under my direction, Sincerely yours, Pieter...." And that was that. So I received my doctorate. And then later on, we were very close and very good friends, and everything was all right. But I had a very difficult time, when I left Groningen to go to Harvard, you see. I thought that by that time, van Rhijn was proud of me, and felt very strongly that I owed it to him to write my doctor's thesis from Groningen and I ran into nothing but trouble, trouble, trouble, from the very stubborn thesis director.

DeVorkin:

This is 1929?

Bok:

No, 1932. I came to Harvard in '29. Well, now, shall we go back to 1926, '27?

DeVorkin:

Yes.

DeVorkin:

We should go back and talk a little more about Leyden. We haven't talked too much about Hertzsprung and your contacts with him.

Bok:

They were very minor ones. Kuiper was very deeply involved. There were three of us, and we all three said, "You've got to be careful with Hertzsprung, he wants every one of us here -- he'll give each of these young upstarts who wants to be an astronomer a pile of 100 photographs to have him discover variable stars." I said, "I don't care. I'm going to work with Oort, and to hell with Hertzsprung." So I stayed away from him.

DeVorkin:

So you had a choice?

Bok:

Oh yes, you had that much. Oh yes, there was. In general, there wasn't much direction at Leyden. You worked in with a person and you learned your astronomy by osmosis. Woltjier was the one who was really assigned to us. But I immediately decided to work with Oort, whom I admired already, from his high velocity star work. Kuiper then said, "I am not going to measure variable stars either. I don't like it. I am going to work with Hertzsprung on double stars." And he did. Kuiper was a firm one. So he went right to Hertzsprung, and Hertz sprung and he wrote a very nice thesis on double stars, spectral components, magnitudes and things like that. Osterhoff said, "Huh, I'm in celestial mechanics. I'm not scared of Hertzsprung." But Hertzsprung got his tentacles in Osterhoff, and he's still measuring piles of plates. Now he's stopped, he's settled down and done nothing in old age. So, Hertzsprung had really very little effect on us, I would say. On Kuiper, perhaps the most, but on me, practically none. de Sitter was always friendly to me. I liked the man. But I can't say I learned anything from de Sitter. The people from whom I learned were Woltjier for the beginning, solid astronomy; Oort; Ehrenfest, and de Haas. They were the four who sort of helped mold me.

DeVorkin:

During the twenties de Sitter was doing celestial mechanics. Why didn't Osterhoff work with him?

Bok:

Well, he was going to. But then Hertzsprung got his tentacles in, and before he knew it he was doing nothing except variable stars.

DeVorkin:

But de Sitter was the director?

Bok:

Yes, but de Sitter was not a very strong director. For example, I never heard de Sitter give a colloquium on the de Sitter universe. Ehrenfest and de Sitter talked very little to each other. Never science. They were socially reasonably good friends. I did not get to know de Sitter until he came to Harvard in 1931; just a year or so before he died he came over and gave a series of lectures.

DeVorkin:

That's right, that went into his book.

Bok:

Yes, Kosmos. Then I heard him lecture, of course. That's when I heard him lecture, when I was at the Lowell Institute, and Shapley made me sort of responsible for him, you know, driving him here and there and all that sort of thing. So de Sitter and I got along beautifully, but he just had never any influence, none whatsoever on me.

DeVorkin:

Let's talk about Ehrenfest and your relationship with him. You took courses from him?

Bok:

No. Never a course. Because I left long before I was entitled to take the theoretical physics course which he taught. That was for fifth year students. And at the end of my third year, I got the offer from van Rhijn that we were just talking about, and I got it ahead of Kuiper and ahead of Osterhoff and ahead of the whole bloody lot, so I felt very proud of myself.

DeVorkin:

How did they all feel about you going to work with van Rhijn?

Bok:

Lely was against it. Lely, my advisor.

DeVorkin:

He was actually advising you. He was against it.

Bok:

Yes, he said so. He said, "Now, Bart, you're doing a silly thing. Here you have the fellowship, with no strings attached. You can do what you want to do. You are free to do." He said, "I'm going to argue against you going to Groningen, for there you will become the chief assistant in the Kapteyn lab." It never occurred to me that anybody would not think that was the greatest honor that could come my way, for that was what it was, you know. But it took me half an hour, and then he said, "OK. I can see that you want to do it and you have good reason. But you had to explain it to me first." So then I went to Groningen, and that worked out very nicely. I wrote several papers there, worked close with van Rhijn; I was his chief assistant and saw him every day and we had very pleasant times together. Then in '28, the important thing was, of course, the International Astronomical Union meeting. For that meeting, all the young ones were made a committee to welcome people. And that's where I met my wife Priscilla, who was then an assistant professor at Smith College, who had saved her money up to go to the IAU in Leyden. I received her at the station, and I received her so well I fell in love with her, and I told her before the meeting was over that I was in love with her and wanted to marry her. Then Shapley helped me get the Agassiz Fellowship at Harvard, and I came over September 7, 1929, and September 8 was a Sunday -- and we took it very slowly and thought things over, and we were married not until September 9th. [laughter] And a year later, we had our son. It was a very romantic doing, and once a reporter from a newspaper said to me, "I suppose you fell in love with her great mind?" I said, "No. She had blond hair. She had mesh stockings and short skirts. What more do you want?" That's how we got started.

DeVorkin:

That's great. Yours has certainly been called by people I talk to, "One of the greatest astronomical romances."

Bok:

Oh yes. It was. H. N. Turner wrote up, after the IAU meeting, "Several close encounters were observed, but no actual captures."

DeVorkin:

Where did he write that?

Bok:

In the "Oxford Notebook" his column that he wrote in The Observatory reporting on the meeting at Leyden, "Several close encounters were observed, but no actual captures." So when we got married, he said, “You were [???]."

DeVorkin:

That's interesting. In going to work for van Rhijn, I see a paper of yours in the B.A.N. in 1927, basically what looks like a spectroscopic paper.

Bok:

That was my first paper.[4] And out of that came one of my finest friendships. Otto Struve had written a silly paper about interstellar absorption. Otto Struve had said that the reason why the interstellar absorption lines have smaller amplitudes in a double star is that there is a "motor boat effect" that the double star produces in the surrounding interstellar medium. That motor boat effect can't quite make the gas of interstellar space go at the same speed, therefore, it has only half the range or velocity.

DeVorkin:

Doppler broadening?

Bok:

Yes. So I got very furious at that. So I decided, I said to Oort, "That man Struve doesn't know what he's talking about, and I'm going to set him straight," and I did an analysis on the oscillating calcium lines, and that was my first B.A.N. paper. Struve was then not a very well-known person.

DeVorkin:

Was that under Oort or van Rhijn?

Bok:

Oort, but I did it by myself. Oort wasn't especially interested or knowledgeable. Hertzsprung was no help. I got mad at Struve. Then Struve did a sweet thing. When I sent him the paper, he wrote me a four page very friendly letter, and he said, "You and I ought to get acquainted. You have some very [good ideas.] Any time that you can come to America, come and look me up at Yerkes Observatory." Ever since Struve and I have been very, very close friends.

DeVorkin:

Do you have any of this early correspondence?

Bok:

No. I'm sorry. I just never kept it.

DeVorkin:

Too bad.

Bok:

My life isn't that important. I am a second level astronomer, not one of the great discoverers. A few minor little things -- lots of fun. It's nice to have a chance to talk about it this way here.

DeVorkin:

Well, no matter how you feel about yourself, your letters would be a very important document. The oral history is what tries to substitute in some ways.

Bok:

'27 was a very important year for me. In '27 Kuiper and Horter (a young geophysicist who never did very well) and I went on bicycles to Norway, to observe the eclipse of the sun. And in that period, I became friendly with Milne, with Stratton, with Smart, and British people, and old man Newall, and German astronomers. During that eclipse, I established an awful lot of contacts that came in very handy, later on.

DeVorkin:

Yes, I can see, those names are very prominent Cambridge and Oxford names.

Bok:

Yes, and it helped me to get started with Milne. Then Milne came to Groningen, and we saw more of each other. Now, there's a very interesting thing I'll tell you, my first day at Leyden in 1924 is interesting. When you were in those days at Leyden, they had the so-called Corps (Student Corps) to which all the reasonably wealthy people of means belonged. They joined the Student Corps like at the one at Heidelberg the student affairs, student organization, what you would call here almost a fraternity, but you had it university wide. Well, neither Kuiper nor I had any money. His father was a carpenter, local merchant in a small town, and mine a sergeant major, so there wasn't money for doing that sort of thing. So I went to Leyden to register. And when you register, you get your outline of when the courses start, and the tradition in Holland is to do that very slowly. So when you register, say, on September 21, the first lecture in Astronomy l will be on October the 5th or something like that. There was nothing to do. So I was in Leyden. But in my envelope was a little sheet that students who were interested in physics, mathematics and astronomy, could join the Reading Room Bosscha that Ehrenfest had started -- it was a physics reading room, with mathematics and astronomy books in it. Bosscha was the tea planter from Indonesia who started the Bosscha Observatory in Java and he had given money for a physics reading room and building in Leyden. Ehrenfest was the one who got that out of him. So I went. And then for a guilder/50 you can become a member of that reading room. So I paid my guilder/50 and went there. What you do is, you come in the reading room, and at Leyden there was no one to welcome you unless you went to the Corps, with all the others. But there was nothing for me to do, except stand there. [I knew no-one.] So I walked in the room, and found out where the reading room was, and the natural thing I did was go to the catalogue and look for the books on astronomy, to see what they had. I'd read quite a few. That's where I was. Anyhow, there stood a tall blond young man, Kuiper, who was also looking through the books. And we were both looking through the books on astronomy. So the way you do in Holland, with a bit of hesitation I introduced myself and he introduced himself. And then there came a typical Kuiper conversation -- this is a lovely one to record. Kuiper said, "And what is your special interest in astronomy, Mr. Bok? Why do you want to study astronomy?" I said, "I'm very interested in Shapley's work on the globular clusters in our galaxy, and role the R. R. Lyrae variables have played in that." And Kuiper said, "Oh, that's a very, very interesting minor field. My interests are much broader." I don't know if you ever knew Kuiper? He was a phenomena. "My interests are much broader," he says. "Have you heard of the problem of three bodies?" I said, "Yes." He said, "It is a perfectly natural physical problem that has not been resolved analytically. And people say it can't be done. That's nonsense. I'm sure that the techniques of mathematics that are being employed at the present time are insufficient for the purpose. One needs to develop a new mathematics to solve that problem. It's my intention to solve that problem." That was my first conversation with Kuiper. And we have always been good friends, in this sort of a way.

DeVorkin:

What does that mean?

Bok:

Oh, not always beside each other always. We fought each other, liked each other, but we got on each other's nerves very often, and so we were very close --

DeVorkin:

-- you're putting your fingers together, sort of crossing?

Bok:

Crossing. Yes. We always crossed each other. And the funny thing is that Kuiper, of course, had a career completely different from mine. I went to Australia and did all the other things. And then we came both back to the University of Arizona, and he ran the Lunar and Planetary Lab, and I ran Steward Observatory. But during that period we always got along fine, never had any difficulties or fights. But we both knew each other's limits, and so we knew well enough how to do things.

DeVorkin:

Did he actually pursue celestial mechanics for a while?

Bok:

He has always been interested in it. Never on a big scale, but, for example, when he dealt with problems like Saturn's rings, he knew how to treat them. We got very good celestial mechanics at Leyden from Woltjier's father, who was basically interested in the satellites of Uranus. That's what he'd written his thesis on. So we had very good celestial mechanics training, which of course now is practically non-existent. For example, I read all four of Tisserand's volumes. That's quite an assignment. I finally read the last two volumes because they discussed the disintegration of comets. I applied the technique to the disintegration of moving clusters.

DeVorkin:

That's very interesting. You mentioned before we started taping, that you'd had this very interesting conversation with Hertz sprung about the diagrams. Was this at Leyden or later on?

Bok:

That was at Leyden. And at Leyden, Hertzsprung lectured on the diagrams. It was then referred to by everybody as the Russell Diagram. And that hurt Hertzsprung no end. He hated that. Hertzsprung said, "I discovered the diagram. I printed it in a footnote in the Zeitschrift fur Wissenschafliche Photographie -- but I printed it. I was the first. Then this man Russell comes, takes a big drum, goes to England, beats the drum, boom boom boom -- appears before the Royal Astronomical Society, turns the diagram by 90 degrees, and makes sure that everybody calls it the Russell Diagram." And you know, the changes, when I came, Shapley was Russell's student. Shapley called it the Russell Diagram. And then there were two of us who got together against this -- Bill Morgan, of Yerkes Observatory, and myself. So W. W. Morgan and I said, "This is silly." And we decided, in all our publications, that we'd call it the Russell Hertzsprung Diagram.

DeVorkin:

I noticed that, instead of the Hertzsprung-Russell.

Bok:

And then later on, I don't know how this happened, but this caught on to people, and it became the H-R Diagram, which it ought to have been. But when we called it the Russell-Hertzsprung Diagram, we sort of felt that we were stepping out of bounds. Shapley at one time wanted to edit it out of one of my papers, and said, "You shouldn't do that, Hertzsprung deserves no credit, what did he ever do about it?"

DeVorkin:

He wasn't aware of Hertzsprung's work?

Bok:

No. And the Zeitschrift fur Wissenschafliche Photographie was a crazy place to publish it, and then in a footnote -- but he had it there. So I showed it to Shapley.

DeVorkin:

You know, I haven't seen that footnote.

Bok:

I had it at one time.

DeVorkin:

I have it at home. That's very important. In other words, he discussed this verbally -- the relationship which he called the Diagram.

Bok:

Yes, and then, apparently, for he drew diagrams for us, he gave basically to us a very disjointed course on how to get colors and absolute magnitudes, but the end result was basically the H-R Diagram.

DeVorkin:

Did he ever talk about his relationship with E. C. Pickering to you or to the class?

Bok:

No.

DeVorkin:

How did he regard Pickering?

Bok:

I don't think I heard him mention Pickering. Russell was very close to Pickering, of course.

DeVorkin:

Yes.

Bok:

I don't know how he regarded Pickering. Yes, he had contact with Pickering, because Hertzsprung was a great admirer of Miss Maury, and so was Bill Morgan, by the way. Annie Cannon is all right, but they are Maury enthusiasts. Antonia Maury was the daughter of the man who set up the Weather Bureau here, did you know that?

DeVorkin:

His daughter?

Bok:

Or granddaughter.

DeVorkin:

I knew she was the niece of Draper.

Bok:

That's right, but she also was the daughter of Matthew Maury, and he was in the U.S. Coastal Geodetic Survey, and basically started the early Weather Bureau up here. I knew Miss Maury very well, and she was a great lady, frankly much brighter than Annie Cannon, but not as outspoken and easy to deal with and easy to recognize. And Pickering had this whole gang of women, including Mrs. Fleming, who supposedly was his mistress -- maybe she was, that's fine, there's nothing wrong with that -- and then he loved Annie Cannon. But he always kept Antonia Maury at a little distance. And she set up, basically, Bill Morgan's spectral luminosity classification system. And Hertzsprung got terribly impressed with her little C stars she got -- you know, the luminous sharp-line ones -- Hertzsprung then corresponded with Pickering, and got very annoyed when Annie Cannon didn't use these luminosity classifications. And then Hertzsprung said, "I've said this before and again -- there are these things, and they are in the Diagram," and basically it was now the H-R Diagram. But it is very nice that justice has been done to Hertzsprung, for he has got full credit, and he knew it before his death. Arthur Hoag helped organize -- you might talk to him about it -- a Hertzsprung symposium, when the old boy was 90 or 91.[5] Each of us had to take him out to lunch and dinner in succession. It was quite a thing. And at that time Hertzsprung became friendly to me, and I could afford to be friendly to him, for he didn't have a pile of plates to be measured. [laughter]

DeVorkin:

Did you ever talk, or have you any recollections, of how Miss Maury regarded her relationship with Pickering?

Bok:

No. Miss Maury was a very great quiet lady. Pickering of course was dead by then a long time, and she never, never mentioned Pickering. We saw her, we had her at our house for dinner and so on and both my wife and I loved her and admired her. We liked Miss Cannon, too. Miss Cannon, for example, was the ideal woman with our children. She was perfect, children's parties, and all sorts of things. She was quite a great lady. The two of them didn't like each other. And that's rather natural. They had these parallel systems of classification. And Pickering had a way of playing off his girls against each other. Yes. Terribly so.

DeVorkin:

I've heard vague recollections that Shapley did a similar thing in the thirties at Harvard.

Bok:

Oh he had fun. Yes, yes.

DeVorkin:

We'll talk about that later.

Bok:

Yes, oh yes. I was in the midst of all that and saw this happen. Yes, but that was a very friendly sort of competitiveness. He and Adelaide Ames, of course, of the Shapley-Ames Catalogue -- that was a tragedy, that Adelaide Ames drowned in a lake in New Hampshire, far too early, 1932. A terrific shock to all of us. And Shapley had a young woman who was sort of the chief of staff, Yenka Mohr, and then he had Virginia Nail and then Constance Boyd. A great many young women, and he used to pay them very low wages. And he used to say to people, "If you give me $500, I will get so much work out of a young woman -- I'll name a galaxy after you --."

DeVorkin:

Is that how Shapley used to go about getting his money?

Bok:

Oh yes.

DeVorkin:

That's very interesting. Regarding Hertzsprung, then -- you would certainly say that he did harbor some sad feelings?

Bok:

Oh, bitter feelings. Just bitter. But he kept it to himself. It isn't well known, but Hertzsprung was married to Kapteyn's daughter.

DeVorkin:

That's right. I was going to ask you about that.

Bok:

There is a Dutch biography written by Hertzsprung's wife about her father.

DeVorkin:

I've seen a number of copies of it. I'm hoping that someday someone will translate it. Do you feel it would reveal more about Kapteyn's early life?

Bok:

Oh yes, quite definitely.

DeVorkin:

Before he got into astronomy.

Bok:

Yes.

DeVorkin:

Well, it would be very valuable.

Bok:

If somebody would do that. Yes.

DeVorkin:

Hertzsprung's wife, Kapteyn's daughter, wrote this when they were together? Were they married while Kapteyn was still alive?

Bok:

Yes, but the marriage was stopped also while he was still alive. The story is that Hertzsprung and Kapteyn's daughter got married, went to Berlin, and during that winter month and the month of December, there was a very cold period, and Hertzsprung had to observe every night, and literally never saw his bride for the first month, something like that. That's the story we heard as little boys.

DeVorkin:

So it had nothing to do with Kapteyn?

Bok:

No, no. Kapteyn and Hertzsprung were not close friends, but they tolerated each other very well, apparently. Hertzsprung of course came to Leyden mostly after Kapteyn had died, you see, for he was still then in Germany.

DeVorkin:

I've heard another story about Hertzsprung, regarding his first use of a large refractor at Potsdam that was a very, very new telescope, and had never been used. He'd brought the lens down to the floor to take the cover off, and some weights that had been in the tube during construction had been jarred loose by this, and they rolled down the tube and broke the lens.

Bok:

Oh, I've never heard that.

DeVorkin:

I've heard that story once.

Bok:

It might well be, for he was in Potsdam at the time where every body who was a professor had his own telescope. That was the way you did it. If you were a professor, you were assigned a telescope.

DeVorkin:

That's an interesting way to do it.

Bok:

Yes. That's the German way. "This is Professor so and so's telescope" -- and then Professor so and so would say to his students, "You may use it Friday night."

DeVorkin:

Well, let's move on. I think we've covered Leyden very nicely. We can move on to Groningen, and your year or two with van Rhijn, although we've already talked about it.

Bok:

I think we've covered that very well. I liked van Rhijn very, very much, and I admired him, but I saw his limitations already very early, you know. And these limitations, we've talked about. They came in reactions to papers. Van Rhijn was not an easy one to deal with, in many ways. But we became very close friends. He married very late in life. He didn't marry until after I had gone to Harvard. It must have been '47 or so when he got married.

DeVorkin:

You mentioned how you came to Harvard. Shapley's position. Had you met Shapley before that time?

Bok:

No. At the IAU meeting, in '28. That meeting was a great thing for me, for there I met my wife. I met Harlow Shapley. I became good friends with Henry Norris Russell, with Frank Schlesinger, with W. H. Wright, and met many of the people from Mt. Wilson Observatory, at that time. Otto Struve was there. That was a great meeting, that Leyden meeting. That was really a wonderful meeting.

DeVorkin:

Did you talk with Shapley at that time about coming to Harvard?

Bok:

Oh yes. Wholly apart from Priscilla, I was determined to go to the United States. In Holland at that time there were no jobs for people who got PhDs. It was even worse than it was here.

DeVorkin:

There were only three universities?

Bok:

Yes. There was Leyden. There was Utrecht. And there was Groningen. Pannekoek had nothing, and that was it. The second thing was, de Sitter told us at the beginning, there would not be a position coming open until eight years from now, when somebody was retiring. And that would be one position, in which then a lector would go up, and in those days, there was no flexibility at all. And therefore, de Sitter called Kuiper, Osterhoff and me in, and said, "Boys, when you get your PhD, you can either become a high school teacher, or you go to the United States." Osterhoff then stayed on, and from assistant became "observator" and fell into what you might call that one position that became available. When I got the Groningen assistantship, that was a very special thing. Jesus, I felt on top of the heap, and almost felt hurt when Mr. Lely said, "No, Bart, I am not going to agree you ought to do this, you are giving up something much more valuable that you had."

Bok:

And then, I was at the IAU meeting, and I wanted to get to America even stronger, because I wanted to marry Priscilla. She was ten years and two weeks older than I was. So it was quite a thing to do. And my father didn't know quite what to make of it. My mother said, "If you love her, you go ahead and do it." That's the way it worked out. Toward the end everything worked out fine. My father was always puzzled by me, because I was sort of the missing link in the family, you know. He wanted me to go into the insurance business. I didn't want that. "You can do mathematics and statistics all you want there [in insurance] much more than you do in astronomy even, and then you have a secure living -- but in astronomy, you'll never make anything off it," he said.

DeVorkin:

You have brothers and sisters?

Bok:

I have a brother, and my brother became a government architect, under the wing of my uncle, and he was a real typical Dutchman. My father always said about me, "I bet you that somewhere back in your mother's family," he was very clear that way, "there must have been a Spaniard who probably seduced your great-great-great grandmother, during the War of 1584!" [laughter] "And Spanish blood, or some queer blood -- in Bart -- he is not a Dutchman at all. But my son Jan, he is a solid Hollander." And my brother Jan, with whom I have the very best relations, agrees with my father that indeed, this was the case -- there must have been foreign blood somewhere mixed in, that gave Bart his hot temperament, and that clearly was of Spanish descent. So, I don't know. Anyhow, so then I wanted to go to Harvard, and I did my examinations for the Candidats, where you take courses, and that went beautifully. I got magna cum laude for my Doctorandus, and then when I got my doctorate, I had all my troubles with van Rhijn.

DeVorkin:

The Doctorandus was from Groningen.

Bok:

Yes. The Candidats was from Leyden. There's a nice story about the Candidats from Leyden that I tell to my graduate students quite often when they fail. Kuiper and I were both young men in a hurry, and in Leyden, you were supposed to take three or three-and-a-half years to get your Candidats. Kuiper and I decided it was silly and a waste of time, and we'd move in faster. We had the Ehrenfest contact, we felt damned cocky, and so we went off and after two-and-a-half announced for the exams. You announce when you want to take your exams, that was the Dutch system at that time. You take certain exams, you have to satisfy certain professors. And I took my preliminary ones, and that worked out OK. Then came my Candidats examination, and the professor of algebra, Old Man Kluyver, whom I liked -- he was a very firm elderly mathematician -- began to ask me about semi-convergent series. Jesus -- I got stuck on the semi-convergent series. So when the Candidats was over, they had this "perspiration room" in Leyden where you sit, you may have heard about that, the famous one ??? they call them, and you sit in there and wait. And I said, Jesus, what's he going to do? Well, in Holland then examinations at the end were mostly confirmation that you had done your tentative exams, but Kluyver got furious at this astronomer who didn't know enough about semi-convergent series. He was chairman of the committee, too. So when I was called in, he said, "Stand up, young man. I'm going to tell you something. You astronomers think you can get away with murder in this place. You think you can get away without having to know mathematics. Listen -- you are the last one who will get the degree without question today. If there comes another astronomer as poorly prepared as you, who knows as little about semi-convergent series, we are going to, for the first time in forty years in Leyden, set an example, and flunk you. You can now go." And at the end, they gave you what they called "the silver hand shake," you had to have 2 guilders 50 in your hand and then [they] said, "Congratulations." And he says to me, "Congratulations, Mr. Bok. What the hell do you care? You got the degree. So what." Anyhow, three weeks later Kuiper was up for the exam. And to make a long story short -- he flunked!

DeVorkin:

No kidding.

Bok:

He was flunked, also with convergent series. I had told him, but he hadn't studied them. And, therefore, Kuiper flunked and was given three months delay to come back. I always like to tell this to students who have difficulties. You know, for Kuiper and I both did reasonably well, especially here in the university. So when the student would come and say, "Oh my God, I failed," I'm no good," -- you know the way -- I say, "let me tell you how Kuiper and I -- ." So the Candidats was rushed, and I was glad I did it, and then at Groningen I did a very careful job with my courses, and that was magna cum laude. Then to Harvard, you see, where Shapley gave me the Agassiz Fellowship, married Priscilla, and came back with the doctor's thesis three years later. And three years was considered in Holland frankly too short a time. The Dutch still had this system by which a man would work for seven or eight years on his thesis, be poor like hell, and then become a high school teacher or something like that. That was the accepted thing.

DeVorkin:

That's really rough.

Bok:

Yes. And that still prevails somewhat in Holland. The idea that for a good doctor's thesis, you must spend at least, after your preliminary Candidats of three years, you must spend at least two more years, then five or seven more years to finish the doctorate.

DeVorkin:

Very difficult.

Bok:

That's very difficult, yes. And by that time, I was under the influence of the United States, and had an assistant professorship promised at Harvard already.

DeVorkin:

-- this is 1932.

Bok:

Thirty two, yes.

DeVorkin:

When you arrived in the United States in 1929, what were your feelings, about doing astronomy?

Bok:

Oh, Shapley and I had corresponded, and Shapley was very helpful. Shapley had assigned to me the study of the spectrum of [Eta]N Carinae before the outburst -- the old line spectrum. And my first paper[6] dealt with n Carinae. And then, I wanted to be an astrophysicist, but Harvard had Harry Plaskett as the director of graduate studies at Harvard, and Harry Plaskett and I didn't agree on things. I wrote a paper that was very critical of Milne's work on shells around stars, that Milne had pure scattering, and I felt it had to be scattering with a cutoff from absorption, which is, in a way, you might now say, the basic idea in 1930 of what is now called the Stromgren sphere. I gave a colloquium on it, which Ehrenfest attended in Michigan, in Ann Arbor, at the university. He was there for the summer.

DeVorkin:

Oh, that was the summer school?

Bok:

In the summer, yes, in 1930. The colloquium was a very good one. I had the paper written up, and Harry Plaskett would not agree that I publish it, because it made critical remarks about Milne's work. The fact that Milne was a good friend of mine had no importance for Harry. But Harry wanted to become the other professor of astronomy at Oxford, and he needed Milne's support, and he stopped my paper on what we now would call the Stromgren spheres.

DeVorkin:

Do you have a copy of that?

Bok:

No. It's gone. And he said, "You remind me of somebody who sets out to do something, and then, he can't conquer the city he wants, so he goes to the countryside and he raids all the villages -- no, I will not agree to have this paper published."

DeVorkin:

This is what Plaskett said about your paper.

Bok:

Yes.

DeVorkin:

Who has a copy of that paper, do you think?

Bok:

Nobody.

DeVorkin:

Nothing at Harvard?

Bok:

No. I threw it away. I told Bengt Stromgren about it. I've got enough credits, that I don't have to say it was a pre-Stromgren in an unpublished paper. So, Milne had had pure scattering in planetary nebulae. And I said, "That is not what's going on in these things. The shells are determined when the hydrogen becomes neutral," and I calculated sizes of the ionized zones. The one who admired the paper was Otto Struve. And he was very annoyed at Harry Plaskett. But then I said, "Oh, I'd better get back to my Milky Way structure. That's really where my strength lies. Forget about astrophysics." So then I wrote on the distribution of stars in N Carinae, the thesis. I had originally planned to write a thesis really on scattering and absorption problems in stellar shells and emission nebulae. It would be very interesting.

DeVorkin:

It was just at that time that they were beginning to realize that planetary nebulae had a white dwarf cores.

Bok:

Yes.

DeVorkin:

And this sort of thing was getting to be a very interesting problem.

Bok:

Yes. Oh yes. And Struve said, "This is one of the most interesting things I've read."

DeVorkin:

You had correspondence on it with Struve?

Bok:

Yes.

DeVorkin:

So there may be some of your letters and his copies at Yerkes.

Bok:

I don't know if they have them. Anyhow, this was a very cheerful period, you know. But you can see how natural it was. [Plane roar knocks out voice.] If you have absorption mixed with scattering, then absorption would be the determining factor. The shell, where you went from ionized hydrogen to neutral, was a thin one, but the minute the neutral hydrogen began to pile up, there was more absorption, and the minute there was more absorption, you get more neutral, and then the neutral dominated. You had a very narrow space between the different stages of ionization. That was the principal thing that I had. There is something about it in a footnote in my n Carinae dissertation.

DeVorkin:

That was Harvard Observatory, Reprint, #77?[7]

Bok:

Yes. There's a footnote there that deals with some of these things, and there is an astrophysical chapter. Shapley had a nice title for my N Carinae thesis. He was very involved in the troubles with Plaskett and the other things and Harlow said to me, "I have a nice title for your thesis. It ought to be subtitled: 'Miscellaneous Nonsense Vaguely Associated with the n Carinae Nebula.'"

DeVorkin:

He couldn't override Plaskett's decisions?

Bok:

Shapley was not involved. Plaskett ran the graduate school for those two years, but he used it basically as a stepping stone to go to England, and he got the Oxford professorship, just what he wanted.

DeVorkin:

He left not soon after that, '33?

Bok:

No, '32. Before I went back to Groningen. For we looked him up. We always remained reasonably good friends. But I just got out of astrophysics and said, I'm going to go back to the Milky Way.

DeVorkin:

You acknowledged his aid in a number of places.

Bok:

Oh yes.

DeVorkin:

I was going to ask you about that.

Bok:

Oh yes. We had to. But looking back at it now, it was a God damn dirty trick. But at the time, you don't always realize that. He gave me fatherly advice. He was about fifteen years older than I am, and he says, "Now, Bart, you've got to be careful, this is not the way to do it, and I will not stand for this being published." So it was all with the "fatherly advice," and only later on did I realize that he really was terribly anxious to get the Oxford professorship, and he wanted to do nothing to offend Arthur Milne. And Arthur Milne wouldn't have been offended. He wasn't the type. Plaskett has always been a very narrow person.

DeVorkin:

How did you find the general atmosphere under Shapley?

Bok:

Oh, unbelievably exciting. Up till 1938-39, Harvard was the great place to be. And then in '39, Arthur Compton invited me to come to the University of Chicago.

DeVorkin:

Arthur H. Compton?

Bok:

He was a very good friend of mine, and whom I'd met on quite a few occasions, and he invited me to come -- he was then dean there and he tried to bring me into the University of Chicago.

DeVorkin:

Was that to replace Frost, who had just died?

Bok:

No. It was a different sort of thing. It had nothing to do with Yerkes Observatory. Arthur Compton wanted to set up good astronomy teaching at the University of Chicago in Chicago, and there was a good physics department, of course, there, of which a very good teaching expert, Lemon, was the chairman. He was in his day very, very famous, as sort of the first forerunner of the people who set up teaching in the right way in physics. Well, Lemon and Arthur Compton got after me to come there. And then Struve was deeply involved and so was Robert Maynard Hutchins. When I saw Hutchins in 1961 at the Center in Santa Barbara, he introduced me and said, "Gentlemen," to all the monks at Santa Barbara, "we have an interesting visitor today. Here comes someone from my past." And I didn't know, I'd only met him once briefly. "Here comes something from my past. This is one of the very few people who had the nerve to turn down an offer that I made to him in Chicago during its great days. This is Bart Bok, pleasure to have you here." That was a fine introduction. But I'll tell you what went wrong there. I would have gone to Chicago, but then Struve asked Kuiper to help me out. Morgan wanted me. I had been for three months at Yerkes during the summer of '35, '36. I'd written The Distribution of the Stars in Space.[8]

DeVorkin:

You wrote it there?

Bok:

No, I wrote that at home, in Harvard, but it was with the University of Chicago Press and Struve was my editor, and Struve had become a very close friend. So Struve and Arthur Compton, who were both pals of mine, were trying to bring me to Chicago, and they got Bill Morgan and Kuiper, whom I knew best, to put in a good word, to try to get me to leave Harvard. At Harvard, there was a counter-attraction, that Shapley had promised to let me have control of the Southern Observatory, since he knew that I was very interested in the problems of the Southern Milky Way.

DeVorkin:

Is that how you became assistant director?

Bok:

Yes. But now I'll tell you the Kuiper story. That's the real angle. The great Gerard Kuiper came and said, "Bart, I've heard they want you for the staff. I think it's an excellent idea. You should by all means accept. It's a very good idea. But you have to keep one thing in mind," he said. "We now have the MacDonald Observatory in Texas," that was '39, "and MacDonald Observatory has a great telescope. I want to make one thing very clear to you -- that you will have no time on the MacDonald reflector, because there are so many keen and important astrophysicists and people at Yerkes Observatory, that we could not add another person to our observing staff. Therefore, you must come to Chicago with the full understanding that some of the smaller telescopes at Yerkes may well be made available to you, but that your principal assignment is to set up teaching, and that there's no one who can do this better than you can." And so, I said, "Thank you...." Kuiper had a very strong idea that I would never be able to do good research. That was very interesting. We had known each other since the very early days, of course, but, he was the great thinker, and I was all right for practical things like lectures and so on.

DeVorkin:

How did you feel about that?

Bok:

Well, he had a hell of a hard life. My life was easy. His life was very complicated. He had to pull himself all by his own boot straps. He lived in a little country town. He was scheduled to become a primary school teacher in the country town, and went to Haarlem to get the education for that, and then by himself, learned enough mathematics to get a qualification for high school teaching. And on top of that, by himself, he passed the state entrance examinations for the university. So he had to do it all himself, whereas in my case, I always was protected all along the line, and life was easy. Well then, we went on this eclipse expedition. We got to know each other very well. Kuiper was a fine fellow to have along there.

DeVorkin:

This was up in Norway?

Bok:

In Norway. But he never washed dirty dishes. That was always left for [???] and me, and he always wriggled out of low assignments, and he was quite a maneuverer that way. And then, he had the feeling always, and he made this very clear, that I wouldn't be able to really do good research. But now I must tell you a very nice story that comes way at the end. About half a year before he died, Kuiper gave a talk at the symposium on the origin of the solar system. He was asked to speak. And that time, Kuiper got real nervous, because he hadn't kept track of what had happened in galactic structure. And Kuiper came here and visited me in this office and said, "Bart, I would like to find some references about dark nebulae and how they all figured in." That was before, of course, the recent outburst of things. So I gave him a whole pile of publications. We were very good friends, in spite of the fact that we knew each other's measure. And then a telephone call from him came. He phoned up and said, "Bart, this is Gerard. I want to talk to you. I have been reading some of your papers. You don't really realize it I think yourself, but you are doing important work!" And if it were anybody else, I would have punched him in the nose. And you know what I said? "Gerard, that coming from you is a compliment." "Yes, I wanted to tell you, for I thought you might not realize it yourself -- you are doing some important work."

DeVorkin:

That's hilarious.

Bok:

He completely forgot. Isn't that nice? I felt so glad then, I didn't get mad about it. I said, "Thank you. That's most generous of you." He can do this. If it was somebody else -- ! It was a very sweet moment. I felt that suddenly I was vindicated. "You don't realize it, that's obvious," he said.

DeVorkin:

Chandrasekhar went to Yerkes around that time.

Bok:

Chandra first went to Harvard.

DeVorkin:

But it seems like he took the Chicago position first offered to you?

Bok:

But that was not deliberate, because Chandra did that a bit later on, after mine. Chandra was already coming to Chicago, quite often, to teach classes in advanced mathematics or dynamics and things like that. And some of the Yerkes people came there. But they wanted someone to teach beginning astronomy and to build up astronomy in a general way. They had one man there, a half statistician, astronomer, who did it at Chicago. He was a nice guy, and he very much wanted me there, to bring some of the current and modern astronomy into the picture.

DeVorkin:

Was Moulton around?

Bok:

Moulton had just disappeared, and it was Moulton's successor who was there. Moulton was a dean, something like that.

DeVorkin:

Well, I don't want to pursue that, but is this call to Chicago what got you the assistant directorship at Harvard?

Bok:

Yes. And then World War II came, with its various complications, and my wife and I had been very active in the Association of Scientific Workers.

DeVorkin:

Yes, how did you get involved in that?

Bok:

Oh, there was a whole bunch of young scientists who had what you might call almost guilty social consciences, who felt that they had paid no attention to the social implications of science.

DeVorkin:

Who started this?

Bok:

Well, Bernal's book[9] did a great deal. That was really what did it. And then, there were various people in the United States -- Harold Urey was at one time involved, Kenneth Tiemann -- so I became at Harvard very much interested in that. That group, looking back at it now, had about half a dozen good Communist members, who tried to use us for party purposes. But I used it for example -- that report that you saw came basically out of that. My interest in writing an anti- astrology report came out of that. The feeling that, if there came a United Nations, that UNESCO or something like that should be under the United Nations. And that membership caused me, in the McCarthy era, a great deal of difficulty.

DeVorkin:

It did?

Bok:

Yes.

DeVorkin:

Were you called up as a witness?

Bok:

Not by McCarthy. But I was a Shapley supporter, and that was awful already. I was called as a witness for the state committee, twice, and went through all this horrible business, and thank God I never was asked to name names, but almost like that. And you see, I'd never been a Communist in the first place. When I went to the state committee I said, "Bring in a whole stack of Bibles, I never was a Communist. I was never asked to become a Communist. If I had been asked, I would have said no. Now, I'd like to tell your committee what I think of you." That was it. But that was a very disagreeable, difficult time. And then came all the problems with the era when Shapley was being investigated, and when his colleagues, Menzel and Whipple and Cecelia Payne-Gaposchkin, all turned against him.

DeVorkin:

Really?

Bok:

Yes. And then Otto Struve was sent to our house. I remember the night we had him for dinner.

DeVorkin:

That was in the early fifties?

Bok:

That was about '54, '55. Struve came and said, "I bring a message from your colleagues to you, Priscilla and Bart." The three of us were then together. I said, "Yes, what is it?" "The message is: will you stop your constant support of Harlow Shapley." It didn't say "turn against him," but "will you stop your constant support." I said nothing. Priscilla said nothing. And Otto looked a little like this (he was normally cross-eyed, he looked even more cross-eyed), and said, "Have I said the wrong thing?" "No," said Priscillla, "Otto, but it's high time that Bart and I get off this reservation." That's when we decided to quit Harvard.

DeVorkin:

But yet you stayed on several more years.

Bok:

I resigned on the first of January, '56. Yes. This was '55. And then I went to Pusey and said, "Mr. President --" Well, there were several other things I didn't like. The Smithsonian affair was part of it. I felt the Smithsonian is a fine thing, but that it would kill Harvard study and that Harvard would be dominated by this very big monster organization. As an organization it deserves to exist but it didn't belong at Harvard Observatory. And with that, the graduate school went way down, and this was a very interesting experience, a very sad one, a very difficult one. Menzel got furious at me, for writing in Priscilla's obituary, the note that you have-- that the years after we came back from South Africa were not happy ones for us at Harvard, and that we thought it was better to leave.

DeVorkin:

But it was true.

Bok:

It was true. And Menzel said, "My God, you have no right to say it. I did everything to make you feel at home." But you know what Menzel, in a staff meeting, had the nerve to say? "I have always sworn that Harlow Shapley was not a Communist. Oh, God," he says, "I hope I won't be asked again."

DeVorkin:

Wow.

Bok:

These things went on.

DeVorkin:

In the meetings?

Bok:

Yes. In faculty meetings he says this. It was an awful time. So then, the simple thing was to get the hell out of it. Then McGeorge Bundy tried to buy me off. Which is a "Bay of Pigs" solution. McGeorge Bundy offered me a job in the School of Education at Harvard. I had very good standing with the early Science Foundation, Alan Waterman was a good friend of mine, and so was L. Hayworth, so I had strong good contacts there. And "Mac" thought he would solve it all by offering me what was then an unbelievable salary of $30,000 a year! My salary was $16,000. He offered me this if I was to become the professor of science education in the School of Education, become the chief contact with the National Science Foundation, in matters of secondary education, and would have a small radio telescope to play with, and do what I wished to do with research.

DeVorkin:

But not what you did develop, the Agassiz instrument?

Bok:

No, the 60 foot was up then already, when Mac made that offer.

DeVorkin:

You mean, that wasn't the one he was offering you?

Bok:

No, that was not what he was offering me. It was separate from the department of astronomy, what my assignment would be: to travel back and forth and be the big politician. And then, we got an offer from Australia.

DeVorkin:

Then you got the offer from Australia?

Bok:

Yes. $8,000 a year. So we went down from 16 to 8. We were offered 30. We had 16. Or 16-1/2. And we went to Australia for 8! But it worked out fine. The whole thing, the salary, everything came out OK. But that's rather interesting. And you have to have a very special wife, who knows what you want to get out of life, to accept that sort of an offer. And it was a smart move, looking back at it now. We could never have done better -- the whole Southern Milky Way was available -- a very fine move. I've never regretted it. But that's what we did. Then I went to Pusey and resigned, without speaking to Bundy or my colleagues first. The President said, "Well, Bart, have you discussed this with your colleagues?" I said, "No. that's what you get paid for. I've had it with the group. I'm just quitting, period. A year from now, I'll be off your reservation."

DeVorkin:

You were building up a very nice radio group.

Bok:

Yes, I started the radio work, yes. That had Heeschen, Lilly and Maddern had their doctors' degrees. The others were all very close to it. But I had twelve of the people that have practically run radio astronomy. Frank Drake was in there, of course. The whole gang.

DeVorkin:

Was there any question that you could continue that if you wanted? Could you have continued running the radio group?

Bok:

We never got onto it, because the thing had become so complicated, and I felt strongly that the radio astronomers ought to have a base in optical astronomy really. So we never discussed it. I just couldn't take it any more at Harvard. There was a second thing that came along, and that was, Whipple made very strong points in our faculty meeting that Harvard couldn't afford to keep Bart Bok any longer. Bart Bok had that silly interest in the Milky Way and he wanted to do radio astronomy of the Milky Way. That was so expensive, and he had some hope in that silly National Science Foundation that was never going to amount to anything. What you should have is military support, he thought. My colleagues had the nerve to tell me to get out of Milky Way astronomy, and to go into meteor astronomy. "Because meteors," says Whipple, "are the cheapest slugs that God almighty sends out for the Signal Corps, and they all love it, and they would support your research. You can do your radio astronomy, but for God's sake, man, get away from your silly Milky Way. There's no point to that. What you ought to do is get into meteors. They are running through the atmosphere. They want to study deceleration, that's the way to study." Priscilla and I were anti-war anyhow, so it just became impossible for us.

DeVorkin:

When you mentioned the faculty members who were against Shapley, you didn't mention Whipple.

Bok:

Oh, he was very strong. Oh, very strong. Oh yes, Whipple, Cecelia and Menzel. Oh yes.

DeVorkin:

Whipple has been interested in radio work ever since the late thirties.

Bok:

Yes, but at that time, you see, Menzel's work was all financed by the Air Force, Sac Peak and so on, and Whipple's work was all financed then by the Signal Corps, and with the Smithsonian coming in, you know, Whipple was scheduled for that. And the thing that I resented most about Smithsonian, was that the Smithsonian was accepted by Harvard without consultation with me and Cecelia. And Cecelia wanted so desperately to have a professorship, she'd do anything. And I wasn't in the mood to take a beating like that. I was given by Menzel twenty minutes to sign a document saying that it was good for the health of Harvard Observatory to have Smithsonian come there. I said, "No, I won't do this." And Menzel was furious, and McGeorge Bundy was furious. What the hell.

DeVorkin:

Bundy was upset, too?

Bok:

Oh, he was very upset. And Bundy and I had been very good friends earlier.

DeVorkin:

What was his position there again?

Bok:

He was dean of the faculty or provost. Anyhow, he ran the whole business. I think provost at the time, something like that. Anyhow, he was married to Mary Lothrup, and his wife was a former Astronomy l student from Radcliffe long before she knew McGeorge Bundy. So Mary Lothrup and I were very good friends, and he had quite a time at home with his wife saying, "You can't do this to Bart Bok."

DeVorkin:

Was he trying to give you this job in education because he thought it was a good thing for you to do?

Bok:

Oh, yes.

DeVorkin:

He wasn't being insincere?

Bok:

No! He thought this was wonderful. This was like a Bay of Pigs solution.

DeVorkin:

Now I see what you mean by that.

Bok:

Yes. He always liked to do this. Bundy is a smart guy, and he thinks about things, the whole thing, and "here is the solution." And then, everybody has to agree: "My God, McGeorge is bright, look at him, he found the solution." And he was furious when I wouldn't agree to it. And then especially when he heard that I went to $8,000 a year, after turning him down for $30,000. He was furious, furious.

DeVorkin:

But he couldn't be expected to understand your scientific interest.

Bok:

Well, I don't know. I think he should have. That's what deans are paid for.

DeVorkin:

Well, we've skipped way ahead here.

[1]Internal Constitution of the Stars (Cambridge, 1926).

[2]“The Stability of Moving Clusters,” Harvard College Obs. Circ. #384 (1934).

[3]A History of Astronomy (Allen and Unwin, 1961).

[4]“On the Oscillating Ca+ Lines in O and B Stars,” B.A.N. 4:9 (1927).

[5]Held in Flagstaff at the Lowell Observatory and published in Vistas Of Astronomy.

[6]”The Spectrum of Era Carinae,” Popular Astronomy 38:399 (1930).

[7]"A Study of the Era Carinae Region,” Harvard College Obs. Reprint #77 (1932).

[8](Chicago U. Press, 1937).

[9]J.D. Bernal. The Social Function of Science. (Routledge, 1939), reprinted in 1967 by MIT Press.

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