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In footnotes or endnotes please cite AIP interviews like this:
Interview of Robert Atkinson by David DeVorkin on 1977 April 22,
Niels Bohr Library & Archives, American Institute of Physics,
College Park, MD USA,
For multiple citations, "AIP" is the preferred abbreviation for the location.
Early life and education in Manchester; World War I; spectroscopy work at Oxford under Frederick A. Lindemann; visits to Gottingen and Berlin in 1920s; ideas on stellar energy source and stellar structure; work and teaching at Rutgers (1929-1937); World War II research on de-Gaussing, ballistics; moves to Greenwich, then Herstmonceaux observatories; their administration and instruments; solar eclipse work; general relativity theory; return to U.S. Also prominently mentioned are: Herbert Jefcoate Atkinson, Irmin von Holton Atkinson, Mary Kathleen Jane Ashe Atkinson, Niels Henrik David Bohr, John Edward Campbell, Arthur Stanley Eddington, George Gamow, I. O. Griffith, Fritz G. Houtermans, Edwin Powell Hubble, James Hopwood Jeans, H. Spencer Jones, Walther Nernst, Henry Norris Russell, Frederick Soddy, Richard van der Riet Woolley; Aberdeen Proving Ground, Balliol College of University of Oxford, Great Britain Admiralty, Indiana University, Royal Astronomical Society, Royal Greenwich Observatory, United States Proving Ground at Aberdeen, MD Ballistics Research Laboratory, and Universitat Gottingen Observatory.
Dr. Atkinson, I know you were born in Wales in 1898, but I’m not exactly sure where in Wales, and I really don’t know anything more about your family and your origins. Who were your parents?
Well, my parents were both born in Ireland, and my mother’s family was Irish for generations back. My paternal grandfather came over from North England. His father wanted him to go into the church, and he wanted to be a mathematician. He compromised on linguistics, and became a very well known professor of Sanskrit and Romance languages, and lecturer in Celtic, and president of the Royal Irish Academy and that sort of thing, a fellow of Trinity College, Dublin. My father was a water engineer, and got a job with a firm making reservoirs for the Birmingham Water Works in the middle of Wales. My mother married him while he was there, and four children were born there. We were six miles from the nearest little town of any size. And horse carriages [were our transportation] in those days, of course. We moved to London for a short while, when the job on the waterworks was finished, and then to Manchester. My youngest sister was born in London.
What did your father do for the waterworks, again?
He was one of the water engineers on the waterworks. Designing and constructing dams. They were all masonry dams, not earth mounds.
That’s good to hear.
They look much better, I think.
What was your father’s name and your mother’s name?
Herbert Jefcoate Atkinson. My mother was Mary Kathleen Jane. Her maiden name was Ashe. My middle name, d’Escourt, goes back to about 1100 on my mother’s side. It was Dessecourt and all sorts of other things, down the centuries. The Ashes came I think from Exeter, and the river Exe was called the Esse then.
Do you know your genealogy back that far?
Well, it’s there, more or less. A whole lot of names of persons in Ireland and that sort of thing. I don’t know if anything is known of most of them. My cousin has a [copy]. I think I have a copy of it too. But I don’t know how authentic all of it is.
Do you have any very notable people in that genealogy? Way back?
No, I don’t think so. My paternal grandfather was probably much the most outstanding, and he wasn’t in that genealogy, of course. My maternal grandfather was head of the criminal lunatic asylum in Dublin.
What was his background?
Oh, Irish all the way back, I think.
I meant professionally.
He was a medical doctor, and head of the criminal lunatic asylum. Some of the people confined there were quite harmless, and were used as gardeners around the place and that sort of thing. But some of them were dangerous. And one of them actually murdered him.
Oh my. Was there any reason for that?
Oh, I suppose he had a spite against him. You can’t tell with lunatics. You can’t tell with sane people, half the time. I never saw him. I never knew him at all. It was before my parents’ marriage, I think.
And you were born in Wales.
Where in Wales?
6 miles from Rhayader. It’s right in the middle of Wales. Very picturesque pair of valleys now, with the lakes there. It was rather bleak and empty at the time.
Your father was working at the waterworks when you were born and he continued to work in that capacity?
Yes. And after, in Manchester, as a civil engineer still, on the Manchester Water Works. Mostly in the office but he got out to the works too, sometimes, inspecting.
Where were you, in your family?
I’m the eldest. I had three sisters and a brother. The brother and one sister are dead now.
What was your early home life like? Did you remain in the Birmingham area?
No, we were never in the Birmingham area. We went from Wales straight to London, for a temporary job there, and then permanently to Manchester. I went to Manchester grammar school, which is one of the best schools in the world, I think. Still counts as pretty good.
Your father’s educational background and your mother’s?
They were both at Trinity College, Dublin.
So you had an intellectual atmosphere.
Yes. Oh yes, more or less. In those days, one would invite one’s doctor and one’s dentist and so on to dinner occasionally. I think it’s hardly ever done nowadays. But it was that kind of atmosphere. In those days, we weren’t wealthy at all, but I know the family had two servants at the time. We never had any servants later, of course.
What are some of your early recollections of what you read? When did you learn to read, before you went to school?
Oh yes. I remember, I could read at about three and a half. I went to school actually very late. My mother taught us all at home till I was nearly ten. The inspector stopped us on the streets and said, what were we doing out of school? We said we didn’t go to school, our mother taught us. He asked us a few questions and he saw we were quite well taught, but of course we had to go to school.
What was the reason for keeping you out of school?
Oh, I don’t quite know. It was a little bit strange, coming from Ireland. Of course, in Wales, there was no alternative; you had to be out of school. There was no school in conceivable range.
How old were you when you moved to Manchester?
I was eight.
So you were still out of school for two more years, then.
One and a half.
How did you finally come to go to the Manchester Grammar School?
Well, I first went to a preparatory school, a branch out in the suburbs near us. It was a little strange of course, because the other students had been there nearly two years when I finally went, so little circles and groups and so on had already formed. Still, I mean, I got along all right. After the first term, I was usually among the two or three top ones. I had quite a number of friends, and at the main school in Manchester I also joined the Boy Scouts, and we went camping. Quite a number of camps, actually.
What were the elements of education that your mother stressed? And did your father have anything to do with your education?
He taught me Latin. Before I learned French, I knew Latin. Before I went to school. At school I had to start French. But I was already quite fairly well along in Latin. Later he taught me some coordinate geometry long before the school got around to it.
This was after you started going to school.
After I started going to the main school in the center of Manchester.
Your education with your parents continued.
Yes, just what a straight line is and this sort of thing, a little bit. When I was twelve I got an open scholarship to the main school. You had to be under 13 to get that. And that paid for my schooling all the way up. Except for books. This is when I was under 13.
And the open scholarship continued. This was a government --
It continued from year to year, yes. No, it was a school affair. The school was endowed. It had quite a bit of land in Manchester. It was founded in 1515, you see. And it had mills and various things, in those days, which brought in quite a bit of income. Then I went up the classical side, because that was my parents’ wish, and I had no particular wish one way or the other.
What was that?
The classical side, and learned Latin and Greek, and composed Latin and Greek verses. I couldn’t put them back into English now if you asked me to. I can still manage in Latin, but my Greek is rather faded. I recognize things more or less when I see them, but I would have to look up a lot of words to read Greek again. I won an open classical scholarship to Oxford. In 1916, that was, when I was 18.
Let’s talk a little more about your early influences in science and mathematics. Your father taught you coordinate geometry. Did you have specific teachers that you recall at the grammar school, that were influential in developing your interest in mathematics and science?
I had a very good mathematics teacher, certainly. He begged me to go for a mathematics scholarship at Cambridge, but I was still very much under the influence of my parents, and anyway I didn’t realize that I could fairly safely count on getting an open scholarship. I knew I could get a closed scholarship in classics to Oxford.
What is the difference?
Well, the closed ones were restricted to a definite school. An open one is available for anyone who can get it, so to speak. The open ones paid more. As it happened, Manchester had a system whereby classes were lumped -- six or ten classes together -- and redivided for mathematics. You might get further ahead in mathematics than anything else, or further behind in mathematics than anything else, depending on where your real interest lay. I think it’s a rather good system. It meant quite a bit of careful scheduling, of course. All that group had to go to mathematics classes at the same time. But that could be done. I happened to get this same master several different times, because he changed classes at the time when I changed. I got him three years running, I think. His name was Chevalier.
He was French?
I don’t think so. I think that they pronounced it the French way, except that we always called him -- what was it? “Shandy.” The masters that had the most influence on us were classical scholars, of course. Our masters were very definitely scholars. There were no mistresses, except in drawing. That was quite usual.
Your parents were very influential in your decision to go to Oxford?
Yes. It was the fact that Manchester had quite a number of closed scholarships to Oxford. I knew I could get a closed scholarship. I was pretty confident of that, anyway. And I don’t think they realized at all that I could get an open one in mathematics in Cambridge, if I really went over to the mathematics side. The mathematics side was only the last two or three years at school.
If they thought you could, would they have preferred that you do that?
Oh, I think they would have let me do whatever I wanted.
What were your interests?
Oh, almost anything, really. The last two and a half years, when I was working for a classical scholarship, we had one hour a week of mathematics still. And actually I played with some astronomical questions then. Just happened to strike them. I remember working out when the greatest brilliancy of Venus would come, that sort of thing, you see, on simple assumptions; I took a circular orbit, for example, and things like that.
What about the reflectivity?
No, I didn’t do anything on that. Just phase angle. But it was interesting, a nice little bit. I had the calculus, of course. Before I gave up mathematics, I’d already had De Moivre’s Theorem. We went quite fairly well on into things.
What took you to that particular question on Venus?
I don’t know at all. As a Boy Scout, I’d learned the constellations, of course. And I’d made a little paper clock-dial with two or three discs on top of each other, and a pin through the middle, to show the time; if one set a radius parallel to the pointers in the Great Bear, and set the date on the other disc, we could read the time. That sort of thing. Just playing about at things. Then I went off to the war.
In 1916 you went to Oxford.
I took my scholarship exam then, but I didn’t go to Oxford. I had to go off to war then.
Yes, early ‘17 I went in the Army.
Was this a volunteer situation?
No. Everybody had to go. I actually volunteered for the Artillery. I’d taken some riding lessons. And that was all right. Then I went to Exeter Cadet School and got a commission -- which was a mistake. I’m sure I hadn’t anything like the maturity to be an officer.
You were about 19?
I was 18 at first. Yes.
How did you come to get the commission? Was it your decision or did they single you out?
Well, if you applied, and had the educational qualifications, of course, they were taking anybody for anything, in those days, really. The losses in France had been enormous. Any kind of an officer was better than none, so to speak. I joined the Army just before the division was pulled out and sent to Italy, so I saw very little actual war. There was very little war in Italy and I missed most of that. The one hostile push there was, in June of ‘18, I was down taking a refresher course. And the final battle, my horse had fallen on me and I was shipped down to Bordighera, on the Riviera, with an ankle out of action. So I saw very little of it.
I imagine you weren’t thinking of any academic things then.
Oh, a little bit, yes. Each gun had a “corrector bar,” a sort of slide rule, which indicated the fuse-setting for any given range, under various conditions; in the howitzers, one could also use a reduced charge, to get a steep drop, but there was no corrector bar to correspond. I worked out one and sent it in, but the war was nearly over. I also took the course in Pelmanism. I didn’t work very hard at it. It’s one of these memory-training things, you know. And that did influence me in one particular way. It did stress that you must make quite sure you wanted to do what you were going to do with your life -- which I’d hardly thought of, at that date.
This was the philosophy behind the memory training?
Yes, one of the philosophies behind it, yes. Definitely. There were all sorts of tricks, of course, mnemonics. But you had to work at it. I still have the books, I think. I haven’t looked at it for a very long time. But it did stress that, among the things you should do, if you’re deciding on a profession, is to make quite sure you want to do it. So I thought it over, and I decided I wasn’t really interested in classics. I was interested in physics.
Had you had any physics, at this point?
A very little, only a year or two. I had one hour a week, I think. We had a year of chemistry before that, that I liked very much. But I didn’t feel like going on permanently in chemistry. Too many names for me, especially in organic chemistry. But physics was fundamental principles and so on. I was really interested.
Did the mathematics appeal to you, in the thermodynamics?
Not frightfully. Mathematics was a method. You had to have it, so to speak, and I worked on it. I’ve never been quick at mathematics. I’ve seen that in various graduate students that I’ve had: some of them are much faster than I. But you just had to have mathematics and so I worked at it. I needed some for general relativity and so on. I did lecture on relativity at Oxford, Elementary.
This was in the twenties?
Yes. I got there in the spring of 1919, from the war.
That’s when you began Oxford.
Yes. It was a classical scholarship, you see, and I told them, well, I wanted to do physics, even without the scholarship, and [would] work my way through at Cambridge if I had to. But they didn’t think that was necessary. They were letting people who came back from the war try anything they thought they could manage. They said I’d have to take “honor mathematics moderations,” it’s called. That’s a half-way exam, and I had to get at least third class honors in it. And I took it in one year and got second class. So I was allowed to go on, and I got a first in physics.
You must have studied on your own then?
Everyone had a tutor. In mathematics I very much had a tutor. Most people went to their tutor in pairs or threes once a week. And mine took me alone, twice a week. He was a dear old man. His name was John Edward Campbell, and he was interested in the Theory of Continuous Groups. He wrote a text book on it. Of course it was completely Greek to me, I had no idea at all -- he didn’t try to teach me that.
What did you discuss?
Oh, ordinary elementary mathematics -- geometry of the ellipse and that kind of thing. I had to do quite a lot of what we would call elementary mathematics.
Oh, this was to pass the moderations.
Yes, pass the “maths mods,” it’s called.
Who was your tutor in physics?
I. O. Griffith.
This was your first year, 1919?
No, I didn’t do any physics my first year. I did only mathematics and then only physics the next two years.
What physics did you read then? Do you remember the books you read?
Oh, things like Preston’s “Heat,” Houstoun, “Light,” Pidduck’s “Electricity & Magnetism,” Sackur’s “Thermochemistry & Thermodynamics.” I learned quite a bit of thermodynamics.
Did you read Planck?
Not at that time, no. No, they weren’t very modern at Oxford. I got a fairly good grounding in classical physics. “Wave Theory of Light” and “Properties of Matter” by Poynting & Thompson, and various things of that sort. But it was essentially old fashioned physics. I knew the Maxwell Distribution of velocities, that sort of thing, yes.
Not in the sense of going into Gibbs thoroughly, no.
But you were aware of Gibbs’ work? By the second or third year?
Sackur quoted him extensively. I knew the black body formula and so on. At Oxford I was at the Clarendon Lab. That’s the older of the two physics labs.
When did you meet F. A. Lindemann?
He was in charge of the Clarendon Lab, and I saw him, I suppose, as soon as I started doing physics. Griffith introduced me to him fairly early. I was working late one evening on some routine experiments, and I was able to get rather more accuracy than they were getting, and he introduced me to him. And Lindemann gradually took me up quite a bit.
Why do you think that was the case?
He knew I was bright all right. And he wanted me to do various bits of research, some of them on things he was interested in. Towards the middle of my two years I suppose, he got the idea of the titanium-oxide bands in stellar spectra. I talked to you about that, did I, yes?
Yes, but we certainly want to cover it here.
Yes. Well, he saw that, at the temperatures that one knew existed in K type stars, titanium oxide would be on the verge of dissociating. He thought it was titanium dioxide, actually. One did in those days. And he figured that you could work out the pressure, from the entire dissociation, if you knew the properties of titanium and its oxide, down to very low temperatures, where the specific heat falls off. And then you need to make some guess at the chemical constants - the Nernst Constants. But that you could do by analogy with sulfur dioxide. It would be a reasonable analogy for titanium dioxide to guess the chemical constant, but not for the reaction otherwise.
The term for specific heat?
The Nernst-Lindemann Theory. Nernst, first of all, got specific heat at low temperatures. He also introduced quantum theory, of course. Nernst was the first to explain that specific heats ought to fall off to zero at low temperatures, and Lindemann refined the formula a little bit, and the Nernst-Lindemann formula was quite well known for a while.
Did you become aware of quantum theory or its development through Lindemann, or through Griffith?
And through other students, too. I remember, it was a friend of mine who first introduced me to the Bohr theory of the atom.
Who was that?
A man called E. N. Allott. He’s still alive, but he went into medicine. He was very enthusiastic. He got a chemistry scholarship at Balliol. Very bright lad. But he was very interested in the physics side - the Bohr theory and so on, as well.
How did you feel about the Bohr theory when you first heard about it?
Oh, I thought it was very fine, of course. I didn’t realize until later that the electron ought to radiate as it went around, and there were various snags of that sort. And of course, one didn’t know the fine structure business until much later.
You heard about this around 1921?
Yes, about then, I suppose.
This was at the time you were working on the titanium oxide?
Yes. And as I said, I was still an undergraduate. But Lindemann put me on to getting specific heat at low temperatures, and it was a matter of working in a vacuum, and making the vacuum seal up tight, and the titanium oxide had to be put into a little silver cylinder and sealed up airtight. And I did quite a bit of glass blowing in those days. I had to make my own mercury vapor pumps. You couldn’t buy them. And I did various other research lines, then and in the next few years.
How did you work on titanium oxide? You were going at it from the experimental side?
Yes. Actually, putting it in a Dewar flask in liquid air, with a heating coil, and watching as the temperature went up, with another little temperature coil. The leads had to be airtight and that sort of thing, and they weren’t, of course, airtight.
How did Lindemann aid you in this research?
Oh, not at all, except he suggested that I should do it, you see. But he wasn’t really a good supervisor. He’d have a bright idea that this or that ought to be done, and then you go ahead and do it, kind of thing. But actually, sometimes the answer was, it couldn’t be done, and wouldn’t get done at all. This one would have got done in time but I had to give it up, to work on my Finals. I worked on various schemes, over the next few years. And finally, after I took my Bachelor’s, I had a three year research fellowship, and I finally got onto what I think is now called foil spectroscopy. You shoot protons through a bit of thin foil, and see what the spectrum is on the other side.
Beam foil, yes. I didn’t use foil. I had a high vacuum, behind a cathode tube I made, and I had to pump the vacuum out quite fast, and I had a little jet of air coming in, and shot the protons through that and took photographic slitless spectra there. I was able to see the hydrogen atoms, where their luminosity was decaying behind the cathode. Quite faint. And then going through the jet they brightened up, and I was able to measure roughly the way the brightness rose and fell. And I saw that the light must have started coming out at once, after they passed the jet, which was very hard to understand. I still don’t know quite how it is. Unless it was neutral atoms that were excited. Because if it was protons, they’d have to capture an electron first, and emit the continuous spectrum, and presumably it would take some time to emit before they could reach the upper states of the Balmer lines.
This resulted in your paper in 1927?
Yes. That’s right.
On “Emission of Light from Hydrogen Atoms.”  It was a very interesting work. At that time of course you called them canal rays.
I was just wondering when I read the paper, were you interested or aware of the problem of the illumination of nebulae at that time? Were you aware of Zanstra’s work and then --
-- No, I think not. Lindemann thought that spiral nebulae were dust in our own galaxy.
He still did, in 1925?
Oh, I think so, yes, at least in 1924.
After Hubble’s work?
Well, I don’t suppose he read all astronomy instantly it came out. He was a physicist, after all. Before I left in #26, he’d come around to seeing that they were outside. But he certainly had thought that, when I first talked to him about it.
When do you think you became aware of this? Not yet, at this point?
Of the fact that they are galaxies outside us?
Well, yes. That’s a very important question in itself. I’m interested in the nebulae, in the application of your own work and interests to astronomical problems.
Well, I don’t suppose, at all. I didn’t think that had any particular bearing. And obviously, you could have fluorescence of atoms, if they were excited by ultraviolet light and so on. But I was working on collision excitation only. The question of just how soon after the impact the light started getting emitted (which was what I’d looked into) did not strike me as relevant to the nebulae, particularly.
The fact that light was emitted from an initially invisible source --
—- oh yes --
-- through this collisional process --
Oh, I took that for granted, of course. Well, I could see that was so.
In 1924, you had a paper on the theory of the aurora. 
Yes, that started with Lindemann’s theory. Vegard, you see, had a perfectly nonsensical theory --
-- that included gas and dust --
It had solid nitrogen.
And Lindemann said, if it was solid nitrogen, there ought to be gas nitrogen too, and I tried quite a while bombarding a little jet of nitrogen in a vacuum with electrons and got no auroral line, of course.
How did you decide that the λ 5578 line was oxygen and not hydrogen?
I didn’t decide that.
It was one of your conclusions in the paper.
Was it really? I’ll have to look back and see what that was. I can’t have had anything very conclusive for it. Yes, of course; I bombarded an oxygen jet in as good a vacuum as I could get, and got a “line” of 5587.4 + 0.2, which I recognized as the leading component of the ordinary “negative band.” I suggested that under auroral conditions another component at 5578 + 0.6 might become dominant. But I was not enthusiastic about this. I had quite forgotten this work on oxygen.
No, you simply made the statement that you thought it was Oxygen 1 as opposed to -- that was the forbidden line -- No, you didn’t say Oxygen 1, you just said Oxygen.
Yes. I don’t think I had any idea it was the forbidden line. With titanium oxide, of course --
-- this is the 1922 paper. 
Yes. After I’d given it up in despair, because I had to go back to my exam work, it still went wandering around in the back of my head, you see. I suddenly realized that I didn’t need the solid titanium metal and titanium oxide at all. You could just estimate the density enough to say, it’s got to be gas. A gas reaction only. So I wrote it on the basis of a gas reaction only. Incidentally, the diagrams printed in that paper are upside down. It’s a whole lot of S shaped curves, and they’re a little different upside down. That was corrected in a later4 issue, but of course the earlier issue couldn’t mention that. I got 10 atmospheres at the time, and I think we were still believing the pressure shift and saying 10 atmospheres.
People were still thinking in terms of solid or liquid particles for the reversing layer?
I think they must have been. And anyway, the pressure shift was known in the lab, so to speak, and somehow there was a shift in the sun that could be ascribed to pressure shift, and they decided that. I think the idea must have been fading out. Well, E. A. Milne’s came fairly soon, of course, and M. N. Saha’s Theory.
Well, Saha was 1920-21. And by ‘22 it was very well known.
Yes. It wasn’t known to me. And I don’t think it was known to Lindemann. At the time. I was struggling to get ready for my Finals, six days of three-hour exams, often two a day.
Uh huh -- Well, I was thinking, known in astronomical circles.
I think that’s fair to say. Saha for a time was at the Cavendish. Did you have any communication with people at the Cavendish, from Oxford?
Did any astronomers take notice of your 1922 paper and communicate with you?
I don’t remember any letters, but there may have been one or two.
Were they at Oxford?
Not particularly. I don’t remember. I read the paper at the Royal Astronomical Society. There was some discussion there. But no, I don’t remember any particular name in connection with that afterwards.
Was that the first RAS meeting you went to?
Yes. I think it was. It was just about the time of my final exams, and I was seriously behind with some of the work.
I can appreciate that.
They used to recommend that you do no work for the last four or five days beforehand, and take a good holiday. And it was good advice, on the whole. But I did work up electromagnetic theory the night before my electromagnetic theory exam, and actually spotted one question that came. I doubt whether even so, the net profit was appreciable, because I’m fairly slow on other things.
And how were the results of the exams?
Well, I got first class honors.
Did you know that you were going to have a research position, a research fellowship for the next three years, at that time?
No, I hadn’t known that.
What were you planning to do? Afterwards?
I had a demonstratorship at the lab. And I still had the remains of my scholarship. It was a five year scholarship. And I also had ex-Army support. I was all right for a year or two. I wanted to read philosophy, from the point of view of Relativity, but Lindemann said he would drop me altogether if I did that. And then I got a Rockefeller traveling fellowship to Gottingen.
How did you get that?
One applied for that. And I suppose people recommended you. I don’t remember now.
You heard about it, or someone mentioned it to you?
It’s quite possible Lindemann mentioned it. If not, Griffith did, my tutor. And J. Franck came over (to Oxford), actually, and it was he who pointed out that I wasn’t interpreting quite right the measurements I got on my canal rays; that the maximum should come after the maximum of excitation. It was a cumulative effect. I’d got a small delay before the maximum light came, you see, and he said that’s just what you must have, even though the effect of the excitation is instantaneous. He was a wonderful man, Franck. And he took me on at Gottingen as one of his direct pupils.
One of his what?
He was my actual supervisor. And he had just got the Nobel Prize that year, too.  I remember, when I arrived in Gottingen the students organized a torchlight procession in his honor, the night he came back from Oslo. I can see it, up behind the hill there, the whole long line of torches, going up to where he lived. Really spectacular.
You were quite excited about working for him?
Oh, he was a wonderful man. I was very glad indeed to be working with him. There were very good people there. They were very nice people altogether.
Was F. G. Houtermans there?
Yes, Houtermans was there, but I didn’t see very much of him at the time. He wasn’t one of Franck’s students.
You were interested in doing experimental work.
Yes, I am always experimentally inclined rather than theoretically I kept getting driven into theory, this way and that, when I hadn’t any apparatus or when some problem bothered me. But essentially, I think my instincts are experimental, and my theoretical work has often been very, so to speak, tangible. Not abstract.
That’s a very interesting attitude, propensity. Because you did do some very interesting theoretical work. Most of your relativity somehow saw its way back to application, in fundamental astronomy, later on in your life.
I did most of it later. But it did not particularly apply to fundamental astronomy.
Let’s talk about Franck a little more. What were the conditions like in his laboratory? How was the equipment and support?
Oh, the equipment was quite good, for the day. It was very modest by any modern standards, of course, but I certainly had all I needed. Including 10,000 volts DC and things like that. And every week, there was a “Rundgang,” where the supervisors all went around all together and talked to each researcher, about what he was doing. And one learned quite a bit in that, of course.
Who was in this group?
Oh, Franck was. And sometimes Max Born but he was theoretical. R. Pohl was. O. Oldenberg, Born and Herta Sponer. Pohl gave the mass-production lectures in elementary physics, demonstration lectures. I didn’t go to those, usually.
Did you meet Born at this time?
Yes, but not much professionally. He and Franck were very much interested in music, of course. I knew very little music in those days but my father used to play the piano. There were various private concerts and things. But one met Born around, certainly, yes. Oldenberg and Fri. Sponer and one or two other assistants, from time to time, those were the principal ones [I knew].
Gamow was --
-- Gamow was on purely the theoretical side. I didn’t see anything of him, practically. I saw more of J. R. Oppenheimer when he came than I did of Gamow. Oppenheimer paid us a short visit.
Gamow was there for a time from Leningrad.
Yes, but he was under Born, I think. F. G. Houtermans had quite a bit to do with him. That is how I got into the thing, of course.
How was that?
When I’d finished, just finished my doctorate --
This was 1928?
Yes, the early fall of 1928. Houtermans introduced me to the very recent work of Gamow showing how α-particles could get out of the nucleus although they had far less energy than would result from sliding down the Coulomb field from radii where it was known to hold; the wave-mechanics allowed them to tunnel through a region where their kinetic energy would be negative. Gamow and Houtermans had then shown that the Geiger-Nuttall relation, connecting the α-particle energy and the life of the parent atom, could be roughly explained on this view. I saw that their model could not really allow any satisfactory wave-function inside the nucleus, and that one needed a model with two independent parameters, the radius and the depth of the “potential well” that one postulated. We calculated values for these from the lifetimes and energies of the α-active elements, and they looked reasonable. Meanwhile, Gamow had shown that there must be a finite probability for penetration of α-particle into a nucleus and this led me to synthesis in stars. We worked on the other idea first, however.
What was Houtermans’ reaction to the two-parameter “pot” or “well”?
Houtermans liked it, and thought it was promising. But he was a little hesitant, and he said, “Let’s talk it over with J. Kudar.” And this is the part that’s libelous.
This is the part that’s libelous, but true. We spent a whole afternoon in the “Fischback” restaurant, in the Zoological Gardens in Charlottenburg, trying to convince Kudar that we were right, and he finally saw it, and he went home, wrote it up, and published it. And we went to M. v. Laue and talked to him and told him the story. I don’t think Kudar did himself much good. We published it then afterwards, but first, the stars, because I said, “Let’s for goodness sake, get this one out before anybody gets in first on this,” and we did the energy of the stars first,  and the other a little later. 
How did you see the application?
Well, I had to take astronomy as a minor on my doctorate at Gottingen, you see.
Well, then we should go back and talk about that.
Yes. Well, I did take one or two astronomy classes. They weren’t terribly interesting for me, but I read Eddington a lot.
Did you have any contact with H. Kienle?
Kienle was my examiner in astronomy, yes, and I did take some of his lectures. They were not concerned with Eddington, as far as I remember; classical astronomy and so on. But I had to take astronomy or chemistry. I had to take mathematics anyway, as one of my minors, and the other could only be astronomy or chemistry. I thought astronomy was much more suitable.
Who else was there in addition to Kienle?
Kienle and O. Heckmann, and H. Siedentopf.
Heckmann was there. I do have the reports for those years, the Gottingen Observatory, and I was interested in your connection with them. You found Heckmann the most interesting?
I don’t know that I talked very much astronomy with him. I was working pretty long hours on the experimental side of things you see, and it takes a long time. My doctor-thesis was on the recombination of positive ions and free electrons. I didn’t get any recombination, but I pushed the limit for it down a bit. (Zs.f.Ph. 51, 188, 1928) I did get some astronomy, enough to do. But I was interested in Eddington, internal constitution, you see. I knew his difficulty with how to catch six particles in one collision at one time. And also, his point that, as he said, any process that’s active at 20 million must be fairly active at 10 million [degrees], and this thing seems to turn on suddenly. He couldn’t explain that at all. Well, that’s wrong, of course. I mean, it just isn’t true, if you’re working on the far tip of the Maxwell distribution, in the same way it wouldn’t be true if you were working on the far tip of the Wien distribution of black body radiation. When you get out there, you can get very sudden dependence on temperature.
You were aware of the debates that Eddington was involved in?
Eddington and Milne. Well, I thought Eddington was right on those, yes.
Synthesis, as opposed to matter annihilation?
Oh, that was primarily Jeans, yes. Well, until I worked out this process, however, I would have been prepared to listen to [Jeans]. I mean, there were quite good arguments for the long time scale, 1014 years or so; Jeans had arguments from the orbits of binaries and various things like that. But I remember feeling, he could hardly explain how an open cluster would stay together as long as that. Then as soon as Houtermans explained the Gamow penetration business, I saw instantly -- I mean, in the same moment, so to speak -- that protons would do anything Eddington wanted. Take a helium atom, if you like, and fire four protons and two electrons in and get beryllium; this would be Be8 which would be unstable. It could break up into two helium atoms, and you’ve got your helium back. I modified that, to build up to oxygen. Neither of us had the mathematics, really for integration of the formulae involved. But Houtermans had already got the integral from Fock. He was around somewhere and Houtermans knew him. He gave us the actual exponential expressions we needed. The average lives came out on reasonable assumptions for the partial pressure and with Eddington’s temperature, running from seconds for helium to a billion years for neon. In equilibrium, the quantities would be proportional to the lifetimes; but equilibrium would never be reached for the heavier elements.
You found a high probability of proton synthesis for the lighter elements that seemed to fit.
Yes. And that’s just in the formula at once, as soon as you have anything there. Well, you could see it was coming. I mean, it had to be there, from Gamow, right away, qualitatively. And if you assume a quasi-steady state, then the abundances come out of it at once, too, of course. I didn’t go into the question of how the middle of the star mixes up to the surface, and you see the central abundance and that sort of thing.
I didn’t go into that at all, no. But I assumed that the surface abundance wouldn’t be all that different from the central one.
You assumed mixing, then.
I assumed some mixing, yes. Well, I think Eddington had more or less assumed it.
Oh yes. Everyone was assuming a tremendous degree of mixing, at that time.
Had you fit your work at that time to Russell’s solar abundances? This was about exactly the same time as his work.
Almost simultaneous. I don’t think I saw his classical paper until I left Berlin for America. I got an offer of a job at Rutgers --
How did that come about?
That came about through K. T. Compton, who had come to Gottingen. He knew Winchester was in charge at Rutgers, and he knew Winchester was looking for somebody, and recommended me to him. People did come and work. I mean, R. W. Wood came. A. H. Compton came, one time and another -- Wood was great fun.
Did they talk to you about proton synthesis?
No. This was at Gottingen before any synthesis ideas whatever.
What was the general regard for your synthesis work?
I gave an invitation talk at the Einstein Tower in Potsdam. On the whole it was kindly received.
Were you excited by this idea of knowing how the stars shine?
Oh yes. It was wonderful, of course. I remember afterwards at Rutgers, walking up and down the corridor, thinking, thinking, thinking. Well, there weren’t any neutrons then. Essentially my “Process B” was asking for them. I remember sort of thinking, “I really am seeing how God works now,” kind of thing, which was really quite exciting. But there was nobody at Rutgers to talk it over with.
Well, let’s not go into Rutgers just yet. Do you want to talk about how you met your wife. I understand that’s a very interesting story.
Well, Houtermans knew her, of course. They were in school together, and he introduced us.
What is your wife’s full maiden name?
Irmin von Holten.
Houtermans knew your wife? Atkinson Yes, they were at school together. He used to try and teach her some physics and mathematics, but she wasn’t very inclined in that line, of course. She was at Wickersdorf. That’s up in the mountains of Thuringia, a “Schulgemeinde,” where pupils had quite a lot of say in the way the school was run, even in who was hired, that sort of thing. They had to take quite a lot of responsibility for things themselves.
That’s a unique situation.
It was fairly unique, yes. Two or three other similar ones gradually budded off from it, and of course, the Nazis were all against it. But when the Nazis came, one of the schools went to Scotland, to Gordonstoun; Prince Philip was there later. One went to Salem and one went somewhere out on the North Sea Coast.
Prince Philip was a product of this educational philosophy?
When they opened a new campus in the British Isles.
Yes. He wasn’t a school-fellow of my wife’s, he’s much younger of course anyway, but he went to a school that had budded off from the one she went to.
Now, you met your wife --
-- in Berlin, of course. I don’t think she came to Gottingen.
She came to see Houtermans or she knew Houtermans there?
She was living in Berlin. Her parents were living in Berlin, and she was doing a little dancing. Her sister was a professional dancer, in sort of Mary Wigman’s style. And the two of them went on a tour. The government sent them on a tour to the eastern provinces, to show German culture to the bordering, nearly Polish Germans, out in the East.
And this story included Gamow, also?
No. I think the story, as “published,” is fairly, largely correct. Some of the implications aren’t, quite, but I think she was going for a walk with Fritz Houtermans one evening, and she said something about the stars, and he said, “Yes, and as of today, I know why they shine,” or something of that sort.
Well, how did she meet you?
He wanted us to meet. I don’t think he ever thought we’d get married, but he wanted us to meet. I don’t know whether he was in love with her or not. She said he was very much of an elder brother always. He was a few years older than her but not as old as me. He was a very likable and very enthusiastic sort of fellow, very interesting. He knew a tremendous amount about all sorts of things. Also very musical. His mother was Viennese. I think his parents were divorced. His father had been Dutch, I think. Houtermans is that kind of name.
When were you married?
We were married in ‘31, after I’d gone to Rutgers. We corresponded steadily, and I came back, and renewed the acquaintance more fully, of course.
So your first several years in New Jersey --
-- I had alone. Two years. I had one year in Berlin, ‘28-’29, teaching at the Hochschule and that was hard work. Practica were all organized in little groups of ten, each of which did one experiment. The next group did a different one, and so on, and each one was supposed to have a nicely mounted and glazed description of what the experiment was, you see, and these weren’t ready. So Houtermans and I and another assistant had to dash around from group to group explaining what each experiment was and how to do it. It was four hours of practically uninterrupted talking five days a week, and I really got hold of my German and my elementary physics, in that year. I’d more or less skipped the elementary physics originally, at least as far as really doing it thoroughly was concerned.
Did you continue to read astronomy?
No, I didn’t have time for much astronomy at that time at all.
But “synthesis” must have still been very much in your mind.
Oh yes. I was still writing these papers, you see. I wrote one more on the atomic resonance in the nucleus after I got to Rutgers. Worked on it alone. I wasn’t really fit to tackle that kind of thing mathematically.
Well, when you went to Rutgers, you went and Compton was there?
No, he wasn’t there. Winchester was in charge there. He’d studied under Michelson. He knew A. H. Compton and he knew K. T. Compton too. It was K. T. Compton who made the connection, so to speak. But he wasn’t there. I think he was at CalTech.
What were the conditions like at Rutgers?
It was teaching elementary physics, of course, to engineering students mostly. That was sophomore level kind of thing. One had a usual sort of class of 20-odd students. Fortunately they all wanted to learn more physics. I was very shaky on how I’d be able to control them, but I didn’t have any trouble actually. They saw that I knew my stuff and they wanted to know it, so it worked out all right.
Why did you take that particular job?
Well, it was the only job offered, at that time.
This was in the Depression.
Yes. The Exchange Crash came soon after I reached Rutgers. It didn’t hit the universities much at first, but we got a salary reduction the year we were married. It hit us then.
That was a sorry wedding present.
Yes. But it might easily have been worse.
Did you have laboratories? Any research support? At Rutgers?
Very little. We could plug in various potentials, and this sort of thing. I did a little of this. I couldn’t really do anything that was valid for synthesis, anything of that sort. And I was kept fairly busy just with the teaching.
How many courses and students did you have?
I had three, I think. Each meeting three times a week, something like that. It was a fairly full load. One year, I gave a demonstration lecture. I had been doing demonstration lectures before, and I worked this up fairly thoroughly, and told them that I was going to collect their notebooks immediately after the lecture each time, they weren’t to write them up, they must take the notes there, and I would see them. And of course there was a near riot, and one simply couldn’t do a thing like that. If they wrote notes they wouldn’t be able to listen to what I was saying, and so on. And I told them they’d got to. And I collected the notebooks and I marked them, and by the end of the year, they’d learned some physics and they’d certainly learned note-taking. And they were quite good by then -- little descriptions, sketches and so on. Of course, the experiments had to work. But they did, generally. And the only thing was that it took about three hours to prepare the lecture, and an hour to give it, and at least three hours more to mark the notebooks. And that was one teaching hour, from the point of view of teaching load. It was effective teaching, but it should have counted for more hours than it did.
How would you compare the teaching, laboratory experiences, and the students and their attitudes, between Berlin and Rutgers? At that time?
I didn’t notice any great difference. In Berlin, I was only a demonstration assistant in the lab. I didn’t have classes myself.
But you did interact with students.
Oh yes, one did interact with them, all right. And mostly they wanted to know and were quite keen to get on with it. They had to, of course. I don’t think at either place they were deeply intellectually interested, or wanted to go outside the course requirements in any way. We wouldn’t expect it.
Would you have appreciated a situation where the students were a little more motivated?
Well, I didn’t feel I had anything to complain of, so to speak. And I did get some graduate students, in experimental work.
What contacts in the area did you have? I of course know that you came to be a close friend of Henry Norris Russell. Did you go to Columbia and the other areas?
Not very much. No. There was no money for that.
How did you come in contact with Russell?
He was away when I first got to Rutgers, but I’d already seen his paper on abundances.  So I was very keen to talk over my ideas with him from the point of view of abundances. And I wrote to him and said, could I come? and of course he said, yes. He was very excited and certainly very pleased. We had lots of interesting discussions. I don’t know how often I went over, but quite often. It’s only 16 miles. I drove over. Once or twice it was foggy and I had trouble getting back. But it was a simple drive. There were no highways in those days, of course -- it was the old wiggly little road.
How did you get there?
Oh, I had a car. I bought that after my first year, I think. I didn’t save anything. There wasn’t any pension. I was terribly casual about things. There was a group insurance and that was all there was. I finally left to go to the Royal Observatory, I had no actual savings, and no pension rights or anything.
Did they have those various programs where you could have accumulated --
No, there was nothing there at that time. Just the group life insurance. I should have taken out something, of course. But we felt, I think and Irmin quite particularly too, that you could only be young once, and you’d better take a trip to Europe if you could manage it and that sort of thing, you see. She wanted to go back and see her people, too, and we managed that.
Well, your conversations with Russell are of tremendous importance to me and tremendous interest.
Yes. I wish I could remember more in detail. But you can imagine -- him being what he was, so to speak, they ranged over everything.
You can start with certainly, your paper that came out in two parts in 1931. 
Yes. Well, there was a competition by the New York Academy of Sciences, a paper on the source of stellar energy, I think. It was certainly on astrophysics. I think about the source of stellar energy. So I thought I’d better write up everything I could think of, in this field. I postulated a second process and all that; and quite a lot on how long stars could live, and all the rest got into that paper. It was pretty long, by the end. It wouldn’t have been as long as that if I’d just been writing a paper for the Ap. J., but it was submitted for the competition, you see. It didn’t get the prize.
A paper by von Zeipel. I don’t think the paper ever got published finally. Russell was very angry that it had gone that way.
Did Russell have anything to do with the competition initially?
Who did? This was the New York Academy of Sciences.
Was there anyone behind that, that you knew well?
Well, I knew whose verdict it was, unofficially. He recommended the prize be divided. The New York Academy wouldn’t divide it.
Who made that decision?
I don’t know who made the Academy decision against dividing it. The verdict itself was by a Princeton man. He had to toss up for it, so to speak. I think he thought he’d give it to the more established man. Russell was very angry.
You found that the relative proportions of elements in the stars were in very good agreement with Russell’s figures for the sun.
Yes, pretty good for the lightest elements only.
But you mentioned this was qualitative agreement. Does this mean the ratios fit, as opposed to the absolutes?
I couldn’t say anything about the absolute values. I didn’t know, of course, how much helium there was, at all. Oh, one didn’t know how much hydrogen there was in those days.
People were coming to the realization that there was an awful lot of hydrogen.
Gradually, yes. I think Russell said to me once, “there was really only a smell of the heavy elements in the Red Giants.”
Only a smell?
Only a smell. Just barely a smell of the heavy elements.
That’s a very interesting and intuitive remark.
That’s the sort of way he would talk, of course.
Well, you had both proton bombardment and electron bombardments. And your big problem was the production of helium. You said there was no problem, once you had helium.
Yes. Well, you didn’t have deuterium or H3 in those days either. One had to more or less assume the events went through something like that, I think. Only you couldn’t make a collision of six bodies. There had to be some helium. But I thought, if there was any, the process would start, and then if the beryllium 8 disintegrated you could gradually get more helium, and enough to do all this with. There was no helium 5, and there still isn’t, I think.
Well, that was one of the two big stumbling blocks of synthesis for a long time.
Yes. Well, it was, of course. But with Hydrogen 2 and Hydrogen 3 and Helium 3 -- you’ve got a bit of a chance.
At the time, when you spoke with Russell, did you ever discuss Milne’s very long paper in the Handbuch der ASTROPHYSIK, or had you read that? Mime’s paper on thermodynamics? Stellar interiors?
No, I don’t think I talked about that with Russell. I always thought Eddington was more right than Mime, whenever they disagreed. I didn’t believe in the singularity at the center of a star, which Milne wanted on mathematical grounds. Actually, of course, it’s a valid idea, so long as you change to another model before you reach the center.
A different model in the central regions will do it.
But Milne at that point seemed to review ideas of stellar evolution. He pretty much summed them up in two different possibilities. One was that the mass of the star remains constant, and the star evolves across the Russell Diagram rapidly, until it stops in quasi-equilibrium on the Main Sequence. And the other possibility was that it evolved through Giants, down the main sequence, losing mass. Did you and Russell talk about these two possibilities? And about stellar evolution in general?
I think he agreed with the conclusions, that really you can’t avoid, once you’ve got hydrogen synthesis; you can’t lose an appreciable fraction of mass, unless you destroy hydrogen, and it didn’t seem to need that any more. Essentially a star didn’t shift much in the Russell Diagram, once it got to the main sequence. And then when it had used up all its hydrogen, it became a White Dwarf. We had a little note in NATURE on that. Funny thing about that was that I thought that note was headed “The Stellar Graveyard.” And I’ve never been able to find a note in NATURE labeled “The Stellar Graveyard.” Just “Constitution of the Stars” or something of that sort, the note was labeled.
You had a note in NATURE in 1931 with Dr. Russell, on stellar structure. 
Yes, that’s the thing, I think. That’s where we say the nuclei of planetary nebulae are White Dwarfs, yes.
The O-type White Dwarfs. And at this point, this was based on Zanstra’s work.
How was this collaborative work arranged? How did you develop it?
Oh, it wasn’t all that much collaborative work. I just went over and we talked about things, and finally we drafted a little note to NATURE, and then there was a mistake and we had to write another one.  But it was just sort of one of the things that was happening in discussion, one time. I talked a certain amount of double stars with him. Not very much. And of course he knew all the stars in the sky, personally, so to speak. He had fantastic knowledge.
You noted in the paper that you concluded that White Dwarfs were at the end of the evolutionary sequence.
Whereas Jeans thought they were at the beginning. What was the basis behind your idea?
Oh, sooner or later they’d use up all their hydrogen. And then they must collapse.
But Jeans had matter annihilation --
-- yes, well --
How did that put the White Dwarfs at the beginning?
I don’t know. I don’t remember that. If the energy was purely due to hydrogen transmutation you had only 108 years for a very bright star. But by the time you got down to the density of a White Dwarf, gravitational energy would do for quite a long time. It should stay there. You’d expect to see them. You wouldn’t expect to see many contracting from the main sequence to the White Dwarf state because they wouldn’t spend very much time doing that. But once they get down there, gravitation will carry them for quite a while.
Did you wonder about the process of the expansion of the atmospheric shell? Around nuclei of planetaries?
No, except that I saw that the shell couldn’t then be rotating very fast. It was said to be rotating. I showed that it couldn’t be. I produced a rather far-fetched idea, for how it got rotating. They aren’t rotating actually, I think. But at that time I thought they were and where does it come from? And I had a short note, I think that may be in the PHYSICAL REVIEW,  I don’t remember, on the rotation of planetary nebulae, some time while I was at Rutgers. And the idea I got was that, if you have a nucleus so contracted that there is an appreciable red shift, and if it is also spinning, but only quite moderately spinning -- I don’t know how but I expect it would only be moderate -- then, an atom out in the shell and receiving a line in emission say would see more or less only one-half the disc of the nucleus illuminated where the red shift and the Doppler effect canceled each other. The side that was approaching you. And therefore you’d get an off-center radiation pressure. That worked out. It could get the shell rotating, if it had 109 years to do it in. But they don’t have that long, of course. But I didn’t know that either at the time.
What about just the pure observation, that here you have something at the end of its evolutionary phase, and it has an expanding shell. Did that get you wondering about the evolutionary place of Giants? At that time?
No, I was troubled to explain the energy source of Giants. And I had to rely on disintegration of beryllium 8 to get them anything. No, I didn’t go into stellar structure. I don’t think anybody perhaps could have, at that stage, gone into stellar structure enough. Certainly, I wasn’t competent to do the integrations involved. There were no computers. To get the kind of break in the structure that you have to have for that nowadays. 
Did you ever think of expansion as the possible direction of evolution, as opposed to contraction?
I don’t know if I thought of that or not.
How about Russell?
I don’t think so. His Giant Dwarf theory had originally been, of course, that all the Red Giants were young, and they contracted. He wasn’t, of course, mathematically inclined at all. I mean, in the sense of working out an interior structure for a star.
He was doing this from the heuristic standpoint?
He was more concerned with the atmospheres of stars all the time, of course. And it was quite complicated mathematics, and I always felt I wasn’t really the mathematician to tackle that kind of thing. It’s been a great labor to do any mathematics, and I always did it simply under the pressure of, really, having to know this thing, so to speak. I never did mathematics for the joy of it.
What prompts me to ask that particular question, other than its very important interest around that time, because by the late thirties, there was plenty of evidence to show with R. Trumpler’s H-R Diagrams and that sort of thing, that the Giants and certain main sequence stars had the same hydrogen abundances, and B. Stromgren was showing that. But you, in your 1931 paper, on atomic synthesis and stellar energy, noted that with synthesis in the interior of the star, the stars must slowly expand. Now, I assume that the degree of expansion wasn’t very much. But what was the source of this?
Oh, that must have been just the change in mean molecular weight. Eddington had formulae connecting the radius and the molecular weight. That wasn’t a major expansion.
The star all the while was certainly a main sequence star.
At that time the spread of the main sequence was extremely large.
It wasn’t all that large.
About a half a magnitude, wasn’t it?
Oh yes, quite that much. But some of that, you see -- H. Haffner and O. Heckmann worked on Praesepe, and they got a color- magnitude diagram. The stars being definitely all at the same distance, you can do a very precise color-magnitude diagram. And quite clearly, there was a second main sequence, about three-quarters of a magnitude above the main one, obviously interpretable as binaries, two stars of nearly the same brightness. The color of a single star but the brightness of two stars -- and therefore three-quarters of a magnitude up. There is quite a clear, faint but visible, second line in the diagram, and they ascribed it to binaries, all right. So quite a lot of the spread of the main sequence could be that kind of thing, in other clusters as well.
This was a little before they really became convinced of the effect of interstellar reddening.
Yes. Reddening was one of the things that was very much in the air when I first went to Greenwich in ‘37.
One didn’t know, with the reddened B stars, whether it was some super-giant effect or some interstellar reddening, that was doing it.
Let me reverse the tape, and ask you a few more questions about your early work on stellar synthesis. You felt that for low density Giants, some other source of helium synthesis must be active, and this was based upon Houterman’s ideas of the instability of beryllium 8.
It wasn’t particularly Houtermans’ ideas. Both, I should say.
Also there was a very strong lifetime influence on your thinking, and in Russell’s thinking. That is, the amount of time that was available to a star.
Yes, there was quite a problem with the very bright stars. I don’t think I ever, or he, really faced up to the question of how you can explain a bright star in an open cluster.
Was this because the bright stars were thought to be young? And you couldn’t see how they --
-- they had to be young. They couldn’t ever get old. They’d use up all their hydrogen.
By bright stars, are these the Blue Supergiants, or Red?
Both, really. The four yellow stars in the Taurus cluster, for example. They’re quite clearly in the Giant branch.
But since they were thought to be in the initial stages of evolution, rather than subsequent stages, after the main sequence, the age restriction was even greater, on luminosity --
They just didn’t have more than 108 years or whatever it was, at that brightness -- no matter whether they got brighter earlier or later -- they couldn’t spend more time than that. In the bright stage. And there they were.
Then it wouldn’t have made any difference, if you’d considered them to be older than the main sequence or subsequent to the main sequence stage, or prior?
Well, it might have suggested -- of course, it didn’t, but it might have suggested perhaps, that they had originally been on the main sequence, and had brightened up as they left it, or something of that sort.
But to your recollection, it did not suggest that to you?
No. It should have. But I don’t think it did. It was a very old problem.
You also had the problem, where most people thought that four hydrogen nuclei plus two electrons equals a helium nucleus plus energy is a very improbable process. Yet you, later on in your paper, came to a feeling that it was not as improbable, as everyone had suspected. Could you explain that?
I don’t know that I could really, nowadays. I’m not sure what was in my mind there. It’s so hard to think oneself back into --
Yes. There was some experimental evidence present, but it wasn’t conclusive, where you had this process here. You had two hydrogens producing deuterium.
And, I guess, a positron. And then helium-4. Well, this is 1936, already. Was it really the discoveries that were made between ‘31 and ‘36 which helped you tremendously?
No, they didn’t help me as much as they should have. Actually, one way or another, I wasn’t reading everything that appeared in those days.
You were teaching heavily, of course.
Yes. Including working up graduate courses by now. Of course, even after neutrons came one didn’t know how long they could stay free, or anything of that sort. They were distinctly newcomers, even in ‘36, really, as far as their behavior was concerned. If I’d really kept up with the early data on atomic properties, I should presumably have got the Bethe cycle as soon as Bethe could get it. But I didn’t. I had a cycle with Beryllium 8 of course, But it seems to me, the relative proportions up to oxygen were more or less in agreement with a steady state build up theory, you see, with nothing going back. And the fact that oxygen was the top of the abundance curve was consistent with the length of time one supposed the universe had existed, so to speak, and the next element could not yet have built up to maximum. But my own feeling at the time certainly was, if the universe lived long enough, higher elements were going to become the ones that reached the maximum. They weren’t up to their equilibrium proportions yet. I was very much concerned about equilibrium proportions. At Oxford, I did attend Soddy’s lectures.
Soddy, Frederick Soddy.
Yes. And he, of course, introduced me first of all to the equilibrium idea. In those days, I knew all the radioactive elements, and their average lives and their branches and so on. All three series.
Did you feel that your work at Rutgers was too demanding of your time and energy? Well, how did you feel about that?
I don’t know, really.
Were you interested in other jobs? That could have been more directed to research, say a possible position with Russell or something?
Russell did offer me one. He in fact offered me two at different times. One fell through.
When was that?
That was when E. U. Condon was going to leave. And then I don’t know quite why it fell through. That was in physics, not in astronomy. I don’t quite know. I’d always felt that probably, when they realized how little theoretically inclined I was, they persuaded Condon to stay on. I wouldn’t be surprised. I really was not theoretical. I would have had a very great difficulty in anything like stepping into Condon’s shoes. He was going to leave and go to MIT or somewhere. Anyway, that was what happened. He stayed on. The position didn’t materialize. And then later, [Russell] offered me a position with him, and that was very difficult. The Greenwich offer came simultaneously.
This was approximately?
And you had feelings about wanting to go back to England?
Yes and no. The position at the Royal Observatory was quite attractive, of course. Though not financially. And Irmin still thinks I made a grave mistake in the choice I made. Maybe I did. Russell was a marvelous man, and I surely was blinder in those days to some things than I am now.
Well, to the actual personality side. He was a marvelous man.
You were blind?
I was blind, possibly. I probably didn’t rate him as highly as I should have. I mean, I knew he was wonderful to talk to in astronomy, a wonderful man altogether. But the two offers came simultaneously. Actually, if I’d taken Princeton, I’d probably have been pretty unhappy as soon as the war broke out. I would have felt that I should have gone back to England then, I suppose.
How did the offer come from Greenwich? Did you hear about a job opening?
No. They wrote and offered. Actually, Irmin had written to or talked to Lindemann, I think. Lindemann talked to them at Greenwich. But that of course was before there was any prospect at Princeton, the second time. Financially, of course, Princeton would have been far better. But also, it would have been much more stimulating in astrophysics. As soon as I got to Greenwich, I thought I simply had to work on fundamental astronomy, you see. That’s what the job was, and I knew very little.
Did you have any understanding of what you were to do, in going to Greenwich?
Oh, more or less, yes. I mean, I knew what other chief assistants had done there, and so on. But I didn’t really know any meridian circle work, or anything of that sort. I had to learn all that up. And of course, the time work. Almost as soon as I got there, well, one year after I got there, there was Munich.
And I didn’t really believe that Chamberlain had brought “peace in our time” at all. It was a case of going out to the country and setting up a time station, in case Greenwich got bombed, as it probably would. That’s all very time-consuming, of course, and there’s very little to show for it afterwards when you’ve done it.
Setting up the alternate facility.
Yes. Short clocks and transits and wireless receivers and climbing trees to get aerials up and all that sort of thing.
You were an experimentalist at heart. This must have appealed to you.
Yes, it was work that appealed to me, all right, but it didn’t conduce to astrophysics. It didn’t really teach much fundamental astronomy, either. But it had to be done and I was there to do it all right. And then, once the war came, after a few months, I went off into degaussing.
How did you actually go off into that work?
Well, the observatory was under the Admiralty, and the Admiralty was looking for scientists, ex-physicists, who could work on the magnetic mines. All the ports of England were shut down, and that meant starvation in a few weeks unless they got them clear again, you see. It was critical.
Who did you work with in this very important project?
I had to go down to Portsmouth, and nominally we were under the Director of Scientific Research in the Admiralty, but actually, the Portsmouth people had most to do with Commander Hext-Lewis. More intimately, of course, the civilian, E. C. Bullard, who was more or less in charge of the section I worked in. But it was all extremely loosely knit. And the permanent scientists there were very plodding and slow. They had wrapped hundreds of turns of cable around a cruiser with great effort, to magnetize it longitudinally. Actually you only need about ten. The multi-pole that you produce by a few turns fades out very rapidly with increasing depths.
Had you realized this?
No. I didn’t realize it in time at all. It was a young lieutenant who really spotted that point. I’m not sure he knew that either. He just decided to try if ten turns would do anything. You could obviously produce enough current through it. We had huge cables, but whether the field would be smooth enough to use, I don’t think he knew. It was a matter of trying. Immediately under the ship, of course, you would place a magnetometer, to measure the vertical field, and move it along and measure again, to get the whole profile.
What was his name?
Payne. And I remember, when we went up to Scotland to the Gairloch, we wound cables around a ship there, and then took readings every 20 feet or whatever it was. And we saw it was a pretty nice smooth field. And this was fairly consistent, with the exception that right on the stern, there was an awful jag. I took one look and said, “I don’t believe it. It can’t be as good as that all along, and then have something that much wrong here.” It was the place where the leads came on, and he’d crossed them for the last two turns at the stern, and they came up wrong way around. And then Hext-Lewis dashed off to look and he came back and said, “You are quite right, he connected it up wrong.” From then on, of course, that process would take out the longitudinal magnetism. You put the positive pole at one end and the negative pole at the other of the ship -- it depends on the ship’s heading when she’s built.
Hm. That’s very interesting. It’s almost like magnetic polarities in igneous rocks.
Yes, the same kind of idea. There’s an awful lot of riveting that goes on in building a ship. If she’s built on a north heading, there’s quite a strong north pole in the bows.
Who was the first to appreciate the importance of this? This problem of de-gaussing?
Oh, as soon as the mines came, you see, we knew we’d have to do something about it. Ships had been blown up all over the place. And then one mine got washed ashore and failed to go off. And so somebody had to open that up and find out.
How it works?
A Navy lieutenant commander did that, out in the mudflats of Shoeburyness. We suspected magnetic effects, you see. So he took non- magnetic tools out with him, and then two or three people, some hundred yards away, [would listen as] he was describing through a telephone about each step as he did it, in case he was blown up before the next one, you see. He deserved a DSO and got it.
I can well appreciate that.
Then we knew how it worked. And then, of course, as soon as de-gaussing came in, they modified the mine over there, made it measure the field where it landed. Otherwise, if it landed by an old chunk of iron or something, it might go off right away. Or, if you made it too insensitive for that, it wouldn’t go off on a de-gaussed ship. So then they made it measure the field where it landed, and then set itself to go off on a little more than that. And this was an addendum to the mine as it stood. Quite obviously, I would say, looking at it, tacked on, an emergency high rush job, to meet our de-gaussing. The scientists at Portsmouth, the establishment, said, “Oh, it must have taken three years on the drawing boards to do.” You could see it hadn’t taken three years on the drawing board. It was perfectly obvious that it was an ad hoc rush job. Hitler had some very good people in their mine work. He really had a lot of good scientists. That really was his secret weapon. And it nearly worked.
How did you and your wife feel about the war? Was your wife affected?
Oh, it was hard on her. She had people over there. But she was always completely anti-Nazi anyway, of course. I think she was anti-war as well. But it just had to be. We just had to fight. No doubt about it. When Chamberlain came back from Munich, she just wept. It was obvious to her. Her people lived in Berlin, and they were bombed. They weren’t any of them killed, but a cousin was in a German raid over England. Her mother and her sister were more or less buried in the basement for a while, and then got out of it, I think. And her father was going very blind, and he went up to stay with a brother up in Lubeck, and her mother and sister went out into the country, left the house. And her father died up there. She never saw him again.
How did your family fare during the war?
They didn’t lose anybody, either. My father died before we got back from America. I went to Egypt first. I was in charge of degaussing in the eastern Mediterranean. We had a commander there who was doing things that we knew were wrong. We couldn’t persuade him not to, you see. And we were discussing what to do, and there was a lieutenant going out to join his staff. But you can’t send a lieutenant to tell a commander what to do. So I said, “Would you send me?” They said, “Would you go?” and I said, sure I would go. So they flew me out. And I was in charge there. They flew him home the next day to give me a free hand. And for a while I was in charge of a mixed force of civilians and naval lieutenants. We got on fine.
You were a civilian?
I was a civilian, yes. The Commander had applied for a motorboat. He very badly needed a motorboat for the big ships and so on, and he’d been turned down by the admiral personally. I went out to the flagship and succeeded in negotiating two motorboats, one of which had to be shared with the captain of the dockyard. I went to see him, and he said he didn’t think he needed a motorboat, and so I consequently had two and I needed them.
What guile did you use to convince him?
Oh, I just talked about what we’d been doing, and they realized I’d been sent out from home especially for this job, and the commander had been sent home, and so on, you see. Whatever problem they’d had with the commander was more or less nullified by that. It worked all right. I didn’t really have to do anything much except not tread on their toes.
So you were responsible for this operation in the Mediterranean.
Eastern Mediterranean, yes. I don’t know why they kept the canal open there. No ships went through. They came as far as the canal from the south side, and they sometimes got as far as Malta from the west. But I don’t think any ships were coming through, much.
Once a ship was de-gaussed, it was permanently de-gaussed?
Yes, you have to keep current flowing in the coils, and set a different current for a different latitude.
Oh, I see, the coils stayed.
Oh yes, but they kept getting washed off and so on. Also, there was a wiping process. You could take a cable, and put a heavy current through it, and rub it up and down the ship’s side. That was done with smaller ships. But it wasn’t so permanent. The really big ones, of course, we put extra coils on the bow and stern, to neutralize the longitudinal magnetism somewhat as well. When I got out to Alexandria, there was a Navy captain of some sort there -- some kind of Australian pirate. He’d done all sorts of things. He’d dealt in horses and God knows what he hadn’t done. Quite a nice old brigand. And he had learned somewhere that you could make a ship safe in five fathoms of water if you de-gaussed her. This is rather too easy a statement. With small ships, and in England, it was true. So we were mostly concerned with de-gaussing mine sweepers and so on; big ships were too big to do much with, really, the big battleships. And several times he came to me and I had to tell him, you see, that down in the Mediterranean, where the earth’s horizontal force is bigger, the effect of changing heading was bigger, and you couldn’t quite do as well. All I could promise was to make it as safe as I could, kind of thing, each time. He came out once and said, “Dr. A., I want you to meet the skipper of the ‘Fellowship,’ a little wooden ship which has an engine I want you to de-gauss and make her as safe as you can.” He was proud of having got it right at last. I said, “Well, just in case you could help me out right away, do you happen to know how many amperes you have to spare?” He said, “We haven’t got any amperes. The ship’s lit by acetylene.” [laughter] All sorts of funny things, yes. But it was very rough and ready altogether, and lots of smaller ships had practically no amperes. I mean, they had a lighting system, but the generator was barely adequate for that. It was hard to keep the voltage on anything like the right figure. It was very hard to convince them that was necessary.
The voltage regulation -–
The magnetic effect was regulated mostly by reversing coils. Reversing turns of the coil. There weren’t any rheostats. There weren’t any ammeters. There was a voltmeter, and you just had to keep the voltage roughly right, and use the right number of turns. And all the instructions to ships were based on that kind of method, because gradually it had spread out to the big ships. You could reverse coils quite easily, but rheostats to carry that current and adjustable D.C. generators just weren’t to be hand. Not many. And when I was sent over as de-gaussing liaison to America, there, they had always had ammeters and adjustable generators, and you could regulate the voltage, and it was done entirely by regulating the voltage and not by reversing coils. So all instructions to ships had to be different. All the theory, of what to do in different latitudes. We had sent ships down South, of course, and we knew what happened to them down South. We knew how much change of coil, how many turns to turn over, and so on. The Americans hadn’t done that nearly so much, but they had made very careful models, in the Naval Research lab, using tinplate, the right thickness and permeability and put coils around them, and saw what happened if you reversed the external field –- in the big Helmholtz coils, to simulate sending the ship south –- and their answer was different. So what was happening, to a deplorable extent, was that our ships would go over to America, and there they’d be measured with magnetometers under them, or with fluxmeters, and they’d be told, “Oh, you’ve got quite the wrong settings, you must do so and so…” And then they’d come back to us and we’d measure them and say, “Oh, those Americans don’t know what they’re doing, they’ve told it quite wrong,” you see. And this was very bad for morale indeed.
Was this one reason you went to the United States?
It had to be ironed out, you see. So then, we found out that when a ship really goes to sea, she works in a sea-way, and a lot of what looks like permanent vertical magnetism becomes temporary; by the time she spends several weeks going out there, half of what was permanent has fallen out. And you need to change the coil more. We managed to unify the theory that way. But we still then had to prevent the Americans from doing too much. The mines weren’t sinking many ships any more. They were immobilizing vast numbers of scientists, and vast quantities of copper coil, you see, and operational research saw that it wasn’t the right thing to do. Well, that wasn’t my discovery. It was Henry Hulme’s. Hulme was the other chief assistant at Greenwich, junior to me, and he came into de-gaussing too. He was more theoretical. He didn’t go back into astronomy afterwards. He stayed on in operational research.
Were you at Aberdeen when you came to the United States? Did you work at Aberdeen?
When I came to the United States during the war, I came to Washington. And then the Washington job gradually became just a “post office” job, transmitting papers this way and that. Interesting in one respect, namely the categories of secrecy. At that time, they were out of step, and our “Secret” was American “Confidential,” and our “Confidential” was American “Restricted,” and our “Most Secret” was American “Secret,” and so on. And this was very difficult. When you shipped a paper over, it was copied in England with its original classification, and then reclassified in England, with their classification, and came back “for information” one classification higher than it had gone out, which of course, is nonsense. The way they cleared it was in a typical navy and military way. They issued an edict that as of such and such a date, the two categories would be the same, would be equal. But neither side would change the meaning of its own category.
Well, it’s just paper work, as usual.
You say you got tired of it?
Well, I got tired of that kind of post office work.
In Washington, right.
And I had resumed contact with Russell, of course, and he told me that E. Hubble was at Aberdeen. I wrote to him and said, could he use a spare physicist. He said, “By all means.” I was taken on there as a consultant, part time, and then whole time. But administratively it was a very awkward situation, though, because people who worked directly under Hubble now found I was in between, one step higher than them. My salary was such that I had to be, so to speak, and that was very awkward. They felt they’d been pushed aside and demoted and so on.
Who were they?
Well, Reuyll mainly. He didn’t come back into astronomy either. He had worked in astronomy. He was a very nice fellow, and you couldn’t possibly blame him for feeling that Hubble’s action in putting somebody between the two of them, was very unfair to him, and it was, in a way. I tried not to interfere too much. I could mostly do extra things outside. It was a very loose organization.
What did you do and what did Hubble do, and how was Hubble to work for?
Oh, it was called exterior ballistics. And astronomy came into it. You send a bomber up with a flashing light, and calibrate it against the stars, and you can tell then where it’s going and when it lets the bomb go, and actually photograph the last bit of the arrival of the bomb, and time it, of course, and get pretty good information on the trajectory.
So you were worried about air resistance. Did you build theoretical models too?
No, we didn’t. We were just concerned with making the observations. Some of the mathematicians did try a little, I think. But the bombs mostly tumbled in those days. They weren’t nicely streamlined. I remember when a big British one came that was streamlined. I had to go down to Eglin Field in Florida to set up an arrangement there for observing its arrival from the bomber above. That’s the experimental station. I realized at once that our little ten-foot-high marker posts weren’t going to be what we wanted here. We wanted great big radio antenna masts and so on, and got that all set up. And the very first flight -- I think they were partly testing the Norden bomb sight, too -- the bomber let fly on the site and the target was a great structure of wood about 30 feet square, and he almost hit it from 30,000 feet. He said he wasn’t ever going to drop a bomb again, because he could never do as well as that again. Pretty well hidden behind the cross wires, you see, he hardly saw it at that height. That thing came down. It was beautifully streamlined, and it came head first all the way down. And landed perfectly. Very nice aiming bomb. Interesting to watch, too. It was a sandy sort of soil, and it went in, and then a great jet of sand came back out of the hole afterwards. It wasn’t explosive, it was just a dummy, and a great jet of sand was shot out backwards, where the compressed air had been driven into the sand ahead of it.
That made you think about craters?
Well, a little bit, yes. But the bomb wasn’t supersonic, of course. And the sand was very soft. It wasn’t very like the moon.
Did you renew your acquaintances with Russell and others while you were in the United States?
Oh, yes, most of my letters to and from Russell, at that time, were to do with problems at Aberdeen, actually. Ballistics and photogrammetry mainly, and that sort of thing. He was on the board of visitors of the Proving Ground, and he came there once or twice. He was getting older then. He had his first heart attack shortly before he wrote me about Hubble.
Was your wife with you in the United States?
Not at first. But it was clear I was going to be staying on there. At first, wives weren’t allowed to come. Then there was a period when they were allowed to come, and I urged her to come while she could. She was up at Edinburgh by then and taking a course in social science, and if she’d stayed another six months, she’d have had a degree that would have been worth something over here. On the other hand, she mightn’t have been able to come. Actually, she crossed in the very worst month of the war, for submarine sinkings, I mean, after the original mine trouble. This was submarine trouble. The ship beside her and the ship behind her were blown up. And they had to leave the flaming hulks and drive on and couldn’t do anything about them. Her own ship was saved by the officer of the watch who managed to execute a very swift swerve when he saw a torpedo coming, I believe. The ships were fairly small. They could move, could turn fairly fast.
How long were you in the United States, about two years?
More. I was 10 months in Alexandria and a short while in Scotland, and then came out in early ‘42. Yes, that would be right. And she came out, I think, late ‘42, ‘43, I forget now. I had one trip out to the West Coast before she came, and another one after she came and I took her along. I had to visit all the ports, you see, and see if they were handling British ships right, because their instructions were still totally different. They had to learn the British instructions. In connection with that, my opposite number was a lieutenant commander in the American Navy.  He and I wrote a lengthy manual for the treatment of British ships. I am probably one of the few foreigners who has his initials on a Bureau of Ships’ monograph. Then I had to go around to see if the stations were doing these things. Well, we got to Brooklyn Navy Yard, and spoke to the lieutenant there, and said, “How are they making out with the manual we sent along?” He said, “Oh, I couldn’t show them that, it’s labeled Confidential, civilians can’t see that.” They were the ones who had to use it, you see, but he’d locked it up. He had to. That had to be disentangled.
I had to go down once to see a ship that was moored out in Chesapeake Bay. They were treating ships that came in there. It was a long way from land so civilians had to live on board ship; they were college students mostly, but they weren’t allowed to mess with the officers. They had to mess with the deckhands.
Was the food the same?
I don’t know. There were some funny things. British things, too.
We’ve skipped over one paper here that you brought out in 1940, which I think was one of your last papers on stellar energy. It was accretion and stellar energy. 
There was a rather short period there when I was still in astronomy, and there was in fact a short period when I was secretary of the Royal Astronomical Society, and had to edit papers. And Hoyle and Lyttleton kept writing papers that I had to correct and edit and rewrite for them, and by the time I’d got one corrected, another one came along. I finally struck. I said, “I’m not going to do their homework anymore.” First, there was one on comets. Lyttleton thought that a comet, if it came round, would contract of its own accord as it got close to the sun. By some weird geometrical effect. And then that it would pick up more matter. He and Hoyle produced a paper in which they totally ignored the question of conservation of momentum, only considered the energy but not the momentum. It was a hopelessly wrong thing, and I wrote a paper in the Cambridge PROCEEDINGS,  and then also a dimensional analysis, using dimensional theory, in the MONTHLY NOTICES. I rather liked that dimensional argument. It was very economical, considering what it produced. Eddington liked it too.
Did you have a series of discussions with Eddington?
Not much, no, just at the meeting itself.
How do you recall Eddington as a person?
I had had some odd bits of correspondence with him, quite early. I wrote to him on some question, concerned with internal constitution. He wrote back very kindly and clearly. It’s quite possible I’ve got that filed away somewhere too. I don’t know where it is now. Moving to and from America and so on played havoc with some of my papers sometimes. You don’t take them all.
What did you do with the ones you left?
Oh, I wrapped them up in paper parcels. Label them and leave them somewhere. I left a lot of things at the observatory. I left some things up in Scotland, at the de-gaussing station we were evacuated to. Some got wet, including my “Eddington.”
With the observatory -- this would be Herstmonceux?
No, at Greenwich. But Greenwich was pretty badly bombed, of course.
Are you sure that these bundles and packages still exist and they’re safe?
Oh, I have them all now, I think, but I don’t know what’s in each one, always.
Are you planning to organize them?
I ought to. A lot of it is rubbish. Early drafts of papers and that sort of thing. I kept a vast amount of junk. That’s the unfortunate part about it. An enormous amount I can only throw away. I ought to do it.
Well, I hope you don’t.
Oh, when there are two or three drafts of every paper, it’s not very interesting. I keep some letters.
Well, let’s move back then to your years at Greenwich. You did a number of things there that I think we’d like to cover carefully -- your ideas about the mirror transit circle, and the political situation at Greenwich, primarily the move from Greenwich to Herstmonceux.
The mirror transit, of course, I got the idea actually, I think, before I left Aberdeen. I wrote it up in a paper in ‘46. 
Had you talked to anyone about that at Aberdeen?
No. They weren’t particularly interested in transit circle work as such. I knew a lot of the defects of the standard conventional transit circle, of course, from Greenwich, and I saw that a plane mirror ought to get rid of most of it, if you could just mount it sufficiently firmly in the axis. So that it really doesn’t fidget.
What were conditions for research like when you got back to Greenwich?
Oh, very difficult, of course. I mean, it had been quite a bit bombed, it was filthy dirty, and the library windows had gone, and there was shrapnel everywhere and water as well. We’d taken down the two big lenses, and boarded over the 36 inch mirror. I put 2 x 4’s all across the mouth of it. That just stopped odd shrapnel, chips, from hitting it, but of course [it would not stop] a bomb. But you don’t get actual direct hits. I don’t think any of the London bridges were totally destroyed, although they tried very hard. It’s hard to hit exactly. There were a series of bombs, little ones, across the observatory, and the 28-inch dome was badly damaged. But the whole place was a filthy mess. London was very dirty in those days. It’s much cleaner now. The books never entirely recovered, of course. It was a matter of trying to get things going at all.
Who was in charge, and what was your --
H. Spencer Jones was still there in Greenwich at that time. He went to Herstmonceux in ‘48. Not that there was anything for him to do there, but it was more pleasant living there, no doubt. I was left in charge of Greenwich.
What were your responsibilities?
Well, everything that was there. We were doing a little observing. One always had the observing notebooks in next morning, and recorded what had been done, and that sort of thing, and might discuss what should be done. Oh, one amusing thing that came up, the ordnance survey. They did a complete re-survey of the country, and they wrote to Greenwich -- of course the correspondence would come to me if it was addressed to Greenwich. And in general there were minor discrepancies all over the place, sort of two or three feet and they had expected that. But the Royal Observatory was wrong. The transit circle itself apparently was out of place some 20 odd feet. I said, “Ah, which way, east or west?” and they told me. I thought, well, I know what’s happened exactly. The ordnance survey has used the old Bradley meridian, and has ignored the Airy meridian, which came in 1850. And at the time the ordnance survey was not on good terms with Airy, and I suppose the ordnance survey felt that if Airy chose to put in a new transit circle somewhere else, that wasn’t their business, and they used the old meridian. Of course, the Airy one was the one that was used in all later international determinations of longitude differences. So the position then was, and I suppose still is, that the longitudes of all countries are based on the Airy meridian at Greenwich, except England itself, which is based on one 19 feet west from that.
Is it still that way?
I think it is, yes. I think they didn’t change it. It’s very awkward to change, you see. All the really large scale maps and so on -- it would be quite difficult. It doesn’t seriously matter, so long as you know about it. But nobody remembered it.
Was it pretty humorous when they realized that?
Yes. Nobody wanted to be too hard on anybody, so to speak. It had been forgotten. But -- it’s still true. However, there’s an Azimuth mark out in Chingford Forest across the Thames, that nobody ever sees nowadays, of course, which is right for the Airy transit circle. To that extent, even English longitudes are on that meridian. But nobody could ever see it nowadays.
Too many trees?
No, just too dirty air. You can’t see that distance in London. They did put a very bright light there [as a surveying mark] and they managed to see it sometimes, but it was so hard to set on, it was just flaring all over the place. Hardly any use.
That was from turbulent air?
Yes. There’s a power station for the electric tramways plumb on the meridian, north of the observatory, just across the river. The Astronomer Royal of that day, W.H.M. Christie, wasn’t alert enough or didn’t have good enough contacts to stop them in time. By the time he realized what was happening, all that could be done was to shorten two of the four chimneys. But the line of sight goes right past a hot chimney, and one can’t expect to get much out of that. And of course, all the north stars are probably in some trouble. One of the reasons for moving. It’s a very bad site for precision astronomy anyway, by modern standards. It’s flat level ground to the south, and a drop to the Thames just a little to the north. You’re on the edge of a cliff, so to speak. And you couldn’t expect uniform refraction, both sides, and all the variation in latitude work did depend somewhat on the direction of the wind.
When did the move start? The large move? H. Spencer Jones went down in 1948.
Yes. Of course it took a couple of years to buy the place. He spent quite a bit of time surveying other places. But they decided this was much the best one.
Who made the final choice?
Well, essentially I suppose it was Spencer Jones’s choice. Officially, the Admiralty decided it, on the recommendation of the Royal Society. It’s a very good site. But Spencer Jones was a little bit influenced still by the conditions at Greenwich. I mean, the Astronomers Royal often used to pop out after dinner, and go to the meridian circle, to help observers observing there. At least they were very liable to, any time. F. W. Dyson used to pop out an awful lot of times. And Spencer Jones -- although he never observed himself after he came from the Cape -- he still, I think, sort of thought in terms of the Astronomer Royal going out and looking at the instruments. So he wanted to put them close to the castle, which is down in a little hollow, and I was horrified. I was sure you’d get a pool of cold air above that lots of times, with an uncertain upper boundary. And I persuaded him to put them up on the very boundary of the estate, a nice smooth symmetrical gentle ridge, and he put them there. I remember going up and surveying all that part. I laid out the sites, of course.
Was he agreeable to that?
Oh, he was quite willing to have it changed. Then he sent me out to Austria. That was 1947.
Yes. To rehabilitate an observatory on the Kanzel near Villach. This was one of four observatories that K.O. Kiepenheuer had persuaded the Nazis to build during the war, solar observatories. He convinced them that, by observing coronal intensities and also prominences and sunspots and so on, you would be able to predict radio fadeouts, which had military importance, you see. So he got his four observatories, one of them being in Austria. It was after the Anschluss and during the war; and when the end of the war came, of course this one was isolated, and a land surveyor got hold of it and planted himself there in charge of it. But he didn’t know any astronomy. And Spencer Jones thought this ought to be changed, and we ought to get astronomy going again, and he went out and looked at it, and then sent me out to get it going. That’s quite interesting work. Very poor conditions for the poor boys who were working there, and one of the jobs I had to do was get them a slightly higher grade of rations, heavy laborer’s rations or something, because they really were treated as though their job was entirely sedentary, and it wasn’t.
This is observing?
Observing, yes. And observing in moderate altitude, 1000 meters. Cold at times, and so on. When I got there, I found that there was a tower which had been built higher up the mountain for a coronagraph. They had the coronagraph, and they had the dome for the tower too, supplied by Zeiss, a nice wooden dome, (not yet assembled) and the tower was there. But they couldn’t use it, because the RAF had established themselves in it with a radar station. And just before I got there, they managed to salvage, with their radar, a plane that was lost over Yugoslavia, and they managed to bring it back, and they said they weren’t giving that station up, and they were prepared to go all the way up to the Prime Minister, and they thought they’d win there -- and I thought so too. So I had to do something else, and I got talking to the Army, as opposed to the Air Force, and it was decided that it would be quite a nice exercise for the engineering troops, who were kicking their heels doing nothing, you see, to build another tower for me up there, and assemble the dome. The dome by that time, being all nice wood, nice clean spruce wood, had rather got distributed among the local farmers, using it for gate posts and all sorts of things. They hadn’t burnt any of it. It was too good a wood for that. And so we had to threaten them with all the might of the British occupation forces, and the Engineers got the pieces back. They built a new tower, and they took quite an interest in the job. They put wrought-iron grilles outside all the windows, and made signs of the Zodiac in the grilles, this sort of thing. They had just got the dome assembled on a circle of bricks by the time Spencer Jones said I really must come back now. He wanted me to plan for the site at Herstmonceux.
So you didn’t get a chance to use the machine.
No. But later on it was named after me. It was called the Atkinson Tower. Spencer Jones had to go out and attend the festivities when it was opened, and he didn’t take me along as well.
I had plenty to do at home. But they realized that I’d done that work, of course, and I also had to get them attached to somebody organizationally. The best thing I could get was the University of Graz, which was quite a long way away, but still the man there was interested, and it was all right.
Is it in operation today?
I think it’s only amateurs now. It was scientifically under the Kiepenheuer group. I mean, they sent their results in to him and so on. Administratively it was under Graz. I’m not quite sure that they are functioning at all, now.
Well, that certainly was an honor for you. It must have made you feel good.
Oh, it was very nice. We went out there later, and the Graz Professor photographed us by the Tower. There is a plaque, also, talking about a symbol of British-Austrian friendship renewed and this sort of thing.
Then Spencer Jones called you back.
Then I planned the Equatorial group. He really just wanted to put six domes up on the hill out there, just plain domes. And he hadn’t even thought in terms of the water supply for them or anything. And the 26-inch was always a photographic telescope. One always developed a plate occasionally, while observing, just to see if something was missed, before the next morning. There was water available there (at Greenwich) and you could do it, any special experimental work you wanted. I thought it would be terrible not to have a darkroom up there. So I persuaded him, it was perfectly true, the welfare administration in the Navy wouldn’t allow us to have no lavatories up there, and we had to, and so I designed a whole physics lab, more or less, and a large room for aluminizing the 36-inch mirror, and another large room to spare for physics observations, two stories. I probably still have a draft of my design. The architect made only superficial changes. I also designed a spectroheliograph cellar. There was one little solar building that was put up before we had an architect. I designed practically every inch of that building, the height of the steps, the size of the windows and goodness knows what. There was a rolled-steel joist which I let the engineering chief design. A rolled-steel joist across under one side of the dome. But otherwise, I designed the whole building.
Was there any question as to what the buildings were going to be designed for? What kind of telescopes? What kind of instruments?
These were for our own telescopes, they had to be. We had a hope of getting another, but that didn’t affect the buildings particularly. One dome was designed for a 30-inch that we didn’t yet have. We had our eyes on the mirror for it. But the telescope didn’t exist. Before I got down to Herstmonceux, it had been made, but it was not delivered in Spencer Jones’s day. (R. v. der R.) Woolley was there by then. It came just after I got there, I think, yes.
Had you had discussions with Spencer Jones and others about the mission of Herstmonceux at its new site? Were there any differences of opinion, problems?
No. The feeling as far as he was concerned then, and as far as I was concerned, was that we must carry on the traditional work of the Royal Observatory; accurate positional astronomy, including fundamental astronomy. A number of stations that had worked on that had dropped out. There was only the Cape in the Southern Hemisphere now. And Meudon in France and Washington, I think. No fundamental observatory in Germany, I think. There was Pulkowa. But there were very few really doing fundamental work. The differential ones begin by knowing what the places of some stars are and then tying the others to these but in fundamental work you have to work from nothing, have to take the same star above and below the Pole to get its absolute declination and absolute right ascension. You have to use circumpolar stars to get that done, to get your latitude fundamentally -- without knowing the places of any stars and declinations, without knowing your latitude, and there are not many observatories that are doing that.
You said that you got into some administrative trouble, in the move from Greenwich to Herstmonceux.
Yes. Well, you see, I spoke to the press.
I see. About what?
About the move. Nothing was really happening, you see -- or very little. Spencer Jones had gone down to Herstmonceux and things were just kind of drifting along and nothing much happening. And the TIMES and the TELEGRAPH both wrote to the observatory, and asked for an interview. Both asked for interviews, you see, and at first I didn’t want to do it. I was terribly busy, correcting errors in the dome designs and all sorts of things. And the TIMES finally persuaded me, so I had to agree to talk to the TELEGRAPH afterwards in a separate interview. And I told them quite a bit about how slowly it was going, you see, and I didn’t blame anybody or name any names, but I said at the present rate it looked like 15 years to complete the move, at least. Meanwhile the observers, the old ones who were practiced and good at it, were dropping out, of course, and the new ones weren’t getting properly trained and so on. I stressed the urgency quite a bit. And one of them, the TIMES man, I think, asked me, “Who was the architect?” And I said, there wasn’t an architect, the engineer in chief was doing it. And he was shocked, you see, and thought there ought to be an architect. But I hadn’t brought the question up, and I didn’t even feel very strongly about it. I’d designed one building myself, and I thought it was quite all right, so to speak. The little solar building; the dome was presented to us, and we had the photoheliograph already. That’s the thing you photograph the sun for sunspot numbers every day, getting pictures of the sun. I didn’t feel strongly about the architect business. Of course, when he put it to me, I was quite prepared to say it was a very suitable arrangement, so to speak. I said, “I must see a proof of the interview, before --
-- of the TIMES article.
Yes. And he sent me a proof. But I didn’t see the first leader -- I don’t know to this day who wrote it. And it said that it was very shocking that the man who so far had designed naval barracks should be doing the Royal Observatory, and this kind of thing, quite strong. And I got into trouble for criticizing a fellow civil servant in public. I was hauled up before the Hydrographer and all sorts of things. I think I convinced them, gradually, that I hadn’t really attacked the Civil Engineer in Chief explicitly, myself, at all, and that leader wasn’t me. But I did get a written reprimand.
This was Hydrographer?
That’s the immediate superior, administratively, to the Astronomer Royal.
It wasn’t originally. It was under the Board of Ordnance originally. It went under the Admiralty, oh, I forget when, some time a little before Airy’s day, I think. Nothing bad happened to me, except that if I’d ever had a chance of becoming Astronomer Royal, that killed it. Perhaps I never had, anyway. I was too old. By the time Spencer Jones retired, I was too old. And I hadn’t really got the presence and the personality for running the place, you know. I hadn’t realized that when I went to Greenwich originally, in 1937.
Was there a lot of pomp and circumstance involved?
Not a tremendous amount, but I mean, you do have to be able to make sure quarrels don’t go on higher up. And that’s one essential of good administration, stop it before it goes to your superior, of course. I did figure, all the time, both when I first went to Greenwich and after the war when I came back to it, I did feel there was a job I could do there. And I certainly had a lot of effect on the actual layout of instruments and so on, at Herstmonceux. But after that we did get an architect, and whereas I hadn’t been allowed to spend enough even to put one course of stone in a blank brick wall, to break it up a bit, he was allowed to use hand-chipped flints and build lily pools and anything he liked. That, of course, was advantageous on the whole, as far as he used them well. I don’t think he used them very well. We finally succeeded in getting a man who could do it, and he had an apprentice. The apprentice was 63. The art was nearly dying. The flints come as little round nodules, you know, in the chalk, and you can split them so they have more or less flat faces. And you split a whole lot of them and use them as ornamental patches on the wall. But for the walks, on the sides of the walks anyway, where you walk about on the flat, he used the rounded nodules as they came, and of course they’re horrible to walk on. I mean, with strips across the path, white stone -- not always at the edge of a step, sometimes at the edge of a step -- and things like that. People fell into the pool, and all sorts of things, at night.
Who fell in?
Well, actually not any of our staff, but some of the summer students that Woolley brought. Woolley did a very good job in that sort of way.
Yes, having a whole summer school, so to speak, and bringing students from outside, some of whom we ultimately engaged. He was very good also at promoting and assigning personnel. He wasn’t as good an instrumentalist as he thought he was. He said he was a hardware man but he wasn’t. He was a very good administrator. But he said himself that he wasn’t interested in nuts and bolts. And you can’t design instruments if you are not interested in nuts and bolts. He’d say, “here is the instrument, you design it.” You’d have to be interested in every single nut if you were going to do a sound job of designing.
When did Woolley come?
You continued to work on the mirror transit throughout all this time?
No. I didn’t start actually working on it until I got to Herstmonceux. And then I went all the way from placing the contract for the bare axis to completing successful tests, in 15 months. I’d shown Woolley it would work, I didn’t -- I did very little more. Except I did design the pavilion for it, yes. But I didn’t do any more actual physical work of measuring and lapping, and that sort of thing. I’d done all that was needed to show that it worked. And the fixed telescopes were just anybody’s job. The fixed telescopes for observing through, anybody could make of course. If you can design a telescope that you can turn round and round and be precise, you can certainly design one that can sit still and be precise. But I did design a pavilion for it, and the Workshop made me a tenth scale model, but I think that’s been broken up since.
How big was the prototype supposed to be?
Eight inch diameter lenses, with a 12 1/2 inch plane mirror. Our own transit circle is seven inch.
What’s the fate of this instrument now?
It’s just laid up in moth balls. It hasn’t been scrapped. The axis and mirror haven’t been scrapped. It’s been pretty well put away, now, left. And for the time being, the model pavilion was quite all right too, but I rather think they wanted to [remove it] -- it was a fairly big thing.
Why wasn’t it followed up?
Woolley didn’t want it. He had, of course, a limited budget. He said he was interested in a mirror transit circle, but if I’d known he was never going to let me do it, I’d have gone to Edinburgh when they offered it me.
When was that?
Oh, when Greaves died. They didn’t actually officially offer it me, but Spencer Jones and Woolley both asked me if I’d like it.
This was Astronomer Royal --
-- of Scotland, yes. Greaves was senior chief assistant when I came, He was senior to me. An awfully nice, extremely kind fellow, but he died soon after going to Scotland. He was overweight and he smoked. But he was a very nice fellow. Terribly kind.
You would have taken that post?
If I’d known that I had no chance whatever of getting the mirror transit circle going in Greenwich, I think I would have, yes. But Woolley offered me everything I wanted, to make it at the time.
How did you feel then when you realized he wasn’t going to follow through?
Pretty bad, of course, but there was nothing whatever I could do about it. He wouldn’t ever say he wasn’t going to do it. He’d say, “Don’t bother me now.” “Leave me a couple of months or so,” that sort of thing, you see. “I do want a mirror transit circle...” But he wanted to design it himself. With mine already working, his would not be necessary, of course, even if it were good, which I did not expect.
Aside from your time and your effort and interest, how much money was put in on that project?
Not very much. One or two thousand pounds, direct Admiralty money. Of course, quite a number of little bits were made in the workshop, for me. I think it was only two thousand pounds, actually, mainly for machining the forging for the axis, and for the mirror. Something like that. And I kept within it, too. It was possible in those days. It wouldn’t be possible nowadays, of course.
What were other primary interests?
Well, I went on several eclipse expeditions. I had this idea that if you go just outside totality, you can photograph the crescent as it swings round. It swings very fast if the Moon’s centre goes close past the Sun’s.
And I got 3100 pictures in just under 3 minutes.
You got it at Mombasa?
Was that the first cinemaphotography?
No, it had been done, in a very amateurish sort of way, in 1912. There was a marginal eclipse that was total and annular, half and half, so to speak, and they thought they could say where the moon was if they photographed it, and found some place, interpolated between other places, where Bailley’s beads were uniformly round it. The resulting place for the Moon depends, of course, on how deep the valleys are. You can’t relate those valleys to any mean moon at all. I had to relate my position angles to the accurate profiles I got from Washington -- traces from Watts’ limb contour work. And he had by good luck two traces, which included the two regions where the cusps came, of nearly the right libration.
This is a paper in the MONTHLY NOTICES.  Is that the “Cinemaphotography of Partial Solar Eclipses?”
Yes, there are three papers. That’s the third one with Murray. The position-angle of the line of cusps was inferred from Watts’s traces and appears as a continuous line; it does pretty wild things. And the dots are what I observed at Mombasa, meaned by tens.
Yes. I am off a little bit there.
-- yes --
It was pretty close.
You caught the fine structure, here.
Yes, when you consider the scale --
What is it, in seconds?
It was in degrees of position angle.
Degrees of position angle?
Yes. On the moon crescent, you see, only half a degree across. A degree of position angle is about 16” on the sky.
Yes. These are the frame numbers.
These are the frame numbers, yes. Up to 3100. Those are the means by tens. The dots are ten exposures each. It’s arbitrary when you get a jump like that; there’s a bead, and the point where you stop measuring on the bead and start measuring on the main body, or vice versa, according to which cusp it is, is arbitrary. You can decide to jump, in the measurements, just when you decide also, measuring up the profile that you’re going to jump.
This is, for purposes of the tape, to recall this later on, this feature is between 1500 and frame 2000, it’s about frame 1700 approximately. This is the part you’re talking about, this jump.
That jump. There are other jumps like that, you know. In which case, there’s a Baily’s bead -- at some point --. It’s the next one down from the main cusp, you see. The cusp is advancing or retreating, and if it’s advancing, the bead appears, but it’s not worth measuring yet. And later on, it joins onto the cusp and you simply have to measure the bead, because there’s no cusp left. But there are a good many frames in between where you might either measure the bead or the cusp. And also, you might, in working out the profile, you see the profile slants down, you put a slanting limb of the sun on it, which is smooth, and you see there, obviously there’s a bead there too. I think I have a Figure for that too. Here’s a piece of the profile you see, and here’s a limb of the sun, and obviously -- where is it now? Yes, the sun is visible here. Here’s the cusp, and here, there’s the bead.
This is Figure 6, page 78.
Yes. And the thing advances or retreats, depending on which cusp it is. The sun was previously here and here and here, shall we say, it’s come on to there, and finally, it nicks through there and there’s a trace of a bead. It’s not worth measuring.
This is where the curve drops below the theoretical path of the sun?
That’s the limb of the sun, yes. In successive pictures, it moves parallel to itself practically, you see, a straight line, on this scale of only a few seconds. Sooner or later, this part disappears, and it joins onto the bead, and you can’t measure what had been the cusp really any more, you must measure what had been the bead. At the point where there is both a cusp and a bead, you have your choice. You have it both here (on Watts’ limb-traces) and in the Mombasa pictures. You decide when you should choose to jump. That’s obvious, you have to jump then. [Someone had to measure some] 3100 position angles. I didn’t do that. I did it for a while, measured every tenth one, to see how it went, then I gave it to an assistant.
Was this your basic idea, though, this whole thing?
Oh yes. Yes. I published it first of all in ‘48. Spencer Jones let me do it all right. Even though the move was on. I got some funds from the Joint Permanent Eclipse Committee.
Did you have any particularly unusual experiences in Mombasa?
We were very luxurious there, as eclipse expeditions go. We were invited to make ourselves at home in the officers’ mess of the King’s African Rifles. And that was very nice indeed. It was built on a cliff over the sea, beautiful early morning seeing out over the water. And everything went very smoothly, really. Almost all the apparatus was duplicated. And so, I thought, well, the weather reports suggest there might be broken cloud, and I decided to put my assistant, J. D. Pope, some miles away, and we set up an alternative station there. Actually his was the one that got the good pictures. I don’t know what went wrong with mine. The cameras were rather primitive. They were 120 frames per second -- nearly ten times the normal, that’s right. But were a bit obsolete and they didn’t always get the frame quite firmly onto its register point and so on. But he got a very good set.
What was the total running time?
A little under three minutes. But the crescent swung around through about 75 degrees in that time. The motion was really very marked.
That’s probably an interesting sight.
Well, you don’t have time to look. I decided that since there’s plenty of light, I could use a prism out of a spectrograph as a mirror, to throw most of the light away, and I used just what came off the prism. And then I filtered that through a green filter, and got rid of the secondary spectrum of the light altogether. And an ordinary small transit telescope lens then rendered excellent definition. It was easy to see that the sun was smooth and the moon was rough. You could easily see that on images 9-mm long. So the seeing and the focus and everything else must have been good. When we tried again in ‘52, the seeing was much worse. It was in the desert and it wasn’t anything like as good. We didn’t finally get anything out of it. And for geodetic purposes, you seldom would, you know, because, I hadn’t realized this at the time, but by the time you got towards the end of the track -- if you want a long track on the earth -- you must be in the afternoon, and the seeing is never so good then.
That’s true. The seeing is certainly best in the morning.
Oh, yes. Morning over the water is excellent.
You became very interested in relativistic corrections for aberration and other corrections of interest to positional work.
I don’t think I ever did relativistic aberration. Over here, I worked with the re-analysis (all this paper stuff is that) of the Greenwich-Cookson Floating Zenith telescope results. I felt sure it was a good instrument. It was. And I thought it would be worth re-analyzing, to get the longitude and obliquity coefficient separately. And it turned out that it was disappointing. Partly because they’d measured two different ways. They’d changed over to a long screw machine in 1930. They had previously used a two-microscope and a scale business, and the two methods didn’t agree nearly as well as they should have. They hadn’t spotted that. And there were also changes of scale. They’d only taken some scale plates now and then. I found I could analyze the results and refine that down quite a lot. But there were some changes of scale, that you couldn’t always be sure of. Wind correction -- well, they only recorded every 45 degrees, so to speak, noting a “northeast” or “east,” and that mightn’t be enough, and only once in the whole duty and that almost surely wouldn’t be enough, and the wind corrections are pretty uncertain. But then, I decided it could be perfectly possible in principle to measure all the plates again, on a modern measuring machine, automatically, and do them all one way, and it would have been possible, but Eggen had thrown the plates away.
Yes. He was chief assistant for a while -- until he quarreled with Woolley. Or Woolley quarreled with him, I don’t know. Anyway, he left.
He had a quarrel with Woolley?
I think he left rather suddenly. Yes. I don’t know what the basis of the quarrel was, or anything of that sort, but he did leave rather suddenly.
He did mainly photometric stuff, didn’t he?
Yes. He was very slapdash. A lot of his stuff, you can’t believe. His absolute magnitudes, in his British publication, are wildly all over the place. I’m surprised anyone would publish it, they’re so obviously improbable. A lot of people say the same about him. He was very slapdash. Had some good ideas. But he threw these plates away -- 25 years of original irreplaceable observations. And the Admiralty already had an archives branch that could have kept them. Even if we did need the space. Evidently we did. So they can never be re-measured.
He was just insensitive to this?
Well, he was interested in astrophysics. He didn’t think these would ever be used again and it was in fact, rather improbable. And it did take quite a lot of space.
But this is the whole purpose of the basic observatory, this kind of thing.
Well, that kind of thing, yes -- but not, that wasn’t the main work, of course.
Yes, but it was one element of it.
Oh, it was one element of it, undoubtedly, yes.
Was he reprimanded at all by the Astronomer Royal?
I think he probably concurred. I don’t know for certain. I always assumed that Hunter, head of that department, concurred too. But when I spoke to him last time I was over, he said he hadn’t known about it. I was rather surprised at that. I wouldn’t have thought Eggen would act entirely on his own.
That is curious.
At any rate, he threw them away.
Eggen’s in Australia now, isn’t he?
Yes. He’s good company. An entertaining sort of fellow altogether.
In 1963, you published a paper which is quite interesting. It’s “General Relativity in Euclidean Terms.” 
Yes. That was a first attempt along that line. I got the actual equations of general relativity only for the isotropic coordinates case. On perfectly simple physical assumptions. You always measure c locally. And you say the measured velocity is c even in a gravitational field, locally, and so on. But relativity postulates that our measuring rods and clocks are ideally correct. And if you change and say that geometry is Euclidean, and the measuring rods and clocks get affected, then you can stick to Euclidean geometry. You have to work out the proper Lagrangian, and I did that. And how the velocity of light will behave in gravitational fields, both radially and transversely. Well, in the isotropic system they are both the same, of course. And I did it for quite general coordinates, afterwards, not necessarily isotropic at all.
Did you ever find if the relativistic error between two observatories on the earth is greater than the observational limitation? Or was it for when the earth was in different points of its orbit?
Oh, I was aiming to get, by definition, the same results as relativity all the time, but on a different philosophical basis. And I think it has some value actually, to be able to think in Euclidean terms, and to say it’s the instruments that change, not the space. People say things as absolutely true of relativity, that are only true in one coordinate system. I mean, they say, for example, if you cross the Schwarzschild boundary, space and time will interchange. It’s quite true that in a Schwarzschild system, they do. But in the isotropic system, they don’t. And that sort of thing. I had one little paper just on that kind of abstract thing, and derived various systems of coordinates that hadn’t been produced before, and that all satisfied general relativity. “Two General Integrals,” I called it.  And I said there, how dangerous it is to tie yourself to one system. You’re likely to start saying things that aren’t true in another system, but purely algebraic fictions. Artifacts. Things about black holes -- the same way. I don’t think they’ve done black holes on an isotropic system, let alone any of the others. I worked out about ten systems of coordinates, all of which satisfy Einstein’s equations equally well. They’re mostly much less useful. They’re complicated. But you can have them.
I was interested in your paper in 1965, on light tracks near a very massive star. 
You were already here at Indiana by that time?
Oh yes. Well, it grew out of some graduate seminar I had given, you see, and it seemed to me quite interesting. I got it out, and there it was. And I drew a figure of what the Schwarzschild boundary looks like, and what the photon circle looks like and so on, in the isotropic system and in the Schwarzschild system. They look very different. But they’re absolutely the same picture, the same physical situation, of course. Only the scale is different. I had later papers, on Particle Tracks and on Light Delays. People don’t realize enough that in special relativity, you can measure coordinate differences but in general relativity, you can’t. You can’t measure coordinate values or differences at all. If you ask, what is the actual value, to relativistic accuracy, of say, for the earth-sun distance, you can’t say it until you express it in a coordinate system. It will only differ by parts in 108 if you take a different system, but of course close in and in a black hole, they can differ very greatly indeed. You’ve got the same physics, all the time. But people talk about the density, when they mean the proper density. Usually Sometimes, they mean the coordinate density, which is, of course, quite different. I’m firmly convinced, there can’t be a singularity at the middle. Because as soon as you go inside the star, or pass any matter at all, you can’t use the original equations any more. You have to use the Schwarzschild interior solution, or something of that sort. And as you go further in, more and more of the matter is left behind you, and you finally wind up at the center, where there is no singularity at all. The density gradient is zero.
All the matter’s outside.
Yes. It’s bound to be. There’s not the least need for a singularity. There may be one other state of matter more dense than the present one. But I don’t believe there can possibly be a singularity. You know, the singularity takes an infinite time to develop, as a rule. Even the Schwarzschild boundary takes an infinite time to approach. And that’s true in all coordinate systems. But the question of what happens to space and time, if you do go past it, depends on the coordinate system quite a lot.
This interest grew out of your graduate courses?
That grew out of the first graduate course. When I first came here, my first semester, Frank (Edmondson) said I could work and lecture on anything I liked, you see. I’d been working on relativity, so I decided I’d lecture on relativity.
Had you studied or had a continuing interest in general relativity up to that time?
Yes, since the ‘63 paper, I had, more or less. Yes.
That was done while you were still in Greenwich?
[I went first to the] Kellogg Lab at CalTech for three months, to work with W. Fowler. My wife met Fowler in England, you see, and he said, why wasn’t I doing something? And she said, “Well, why don’t you ask him?” And he did. So I had three months over at Pasadena. That was quite interesting. I worked on relativity there quite a bit, and produced a tensor for a contracting star, but without any rotation.
This is before you came here?
It was ‘63, I think, just after my Royal Society paper. I believe it was ‘63. I retired in ‘64.
How did you find Cal Tech? Was that the first time you’d been there?
Practically, yes. I think I had visited it. Yes, I had been up at Pasadena when I was de-gaussing still, at Long Beach. But essentially it was the first visit. Obviously a very active place, much too big to take in, in a short period.
But when you went there then in ‘63 how did you find it? Pleasant?
Oh yes, it was very pleasant. There was also a time that I was there to look again at the red shift plates. I wanted to see whether the separation of the H and K lines had any age dependence. That brought me several years later, to a very short note I published in the PHYSICAL REVIEW called “Secular Changes in Atomic Constants,”  about a two-page paper.
What were you looking at the H and K in --?
In the distant nebulae. The actual red shift plates. Of course, all Hubble and Humason needed was the mean red shift of the two lines. And I wanted the difference between the two, which is very much harder to get with accuracy, of course, and I finally decided, I couldn’t get it. But about at the same time, somebody did answer the question, from the emission spectra, I think of quasars. The emission lines, of course, are very much easier to measure, much more light. And they found that they’d have to suppose, if the fine structure constant changed at all, it was I think, less than one part in two times 1010 per year, something of that sort. That’s all they could get out of it. I hadn’t been able to get anything out of it. The difference between the two lines was just too vague. It’s hard sometimes to tell which the line was.
How far back does your interest in general relativity go?
Well, I did a little even at Oxford. I gave a course in special relativity. But I didn’t do much in general relativity, certainly. I mean, I probably did the red shift. The advance of perihelion. But I did it in a very lay person sort of way. I mean, I didn’t even realize at that time that most of the advance of Mercury’s perihelion is classically explainable, due to the outer planets. It’s quite large. I don’t believe I even knew that then.
During the thirties, did you follow the debate on the white dwarfs, as to whether relativistic degeneracy or non-relativistic degeneracy applied?
Not at that time, no. And J. R. Oppenheimer and Snyder and so on looked at it. I didn’t really go into that at that time.
But you were interested in white dwarfs momentarily at least.
Oh, they seemed to be an obvious, as I said, stellar graveyard, yes.
How did you come to Indiana?
When I was retired at Greenwich, I wrote to various people. And I don’t think I even wrote directly here. Oh yes, B. Pagel had been over, and he told me that there was probably a vacancy here. And so I wrote, and there was. And F. K. Edmondson took me on. It was only as visiting professor. I never got firmly established, so to speak, the idea being that I was too old, and I don’t believe actually that I was, now. I’d have had to pay towards my pension but I would have had a pension. But I had four years, I suppose, on full time, and a couple more, they carried me outside the budget somewhere on half-time jobs. And then I said, I’d had enough deadlines anyway.
You went to Cal Tech before you came here.
Did you know that you were coming here when you went to Cal Tech?
No, not at all.
Were you going back to Greenwich?
Oh yes. We went over to the Berkeley meeting also, the IAU, and we were going back after that. We rented a car for a while after that, and did some of the Southwest which we hadn’t seen before, on the theory that we’d never get to this country again.
You enjoyed the Southwest?
Oh yes. And Irmin enjoyed it very much, of course, because she loves heat. More than a certain amount of heat, I find exhausting, but even so, I loved the Southwest very well.
Is it dry heat that she likes?
Yes. She likes it dry. We saw quite a number of places there that we hadn’t seen before.
You were telling me about your marvelous camping trips.
Yes. Well, on that trip we didn’t camp, of course. We hired a car. Picked it up in Las Vegas, I think, and dropped it again at Albuquerque.
If we can just sort of wind things up a little bit now, how do you feel about your very interesting and varied career that you’ve had over these years?
Oh, well, I probably should have made other choices lots of times. I don’t know. You can’t tell. It’s been interesting as it has turned out, undoubtedly. I’ve never been bored.
What do you think was your most fascinating project? The one that pleased you the most?
I suppose, the atomic synthesis would have to count as one. And maybe the Mombasa eclipse. Those things were successful, as far as they went. There was also the York Minster astronomical clock, and my Standard Time sundial.
So many of the things you’ve done sound like such interesting things to do.
Well, they were of course, yes. And it’s hard to pick out any one, entirely. We haven’t touched on differential librations.
I was forced into that by the Mombasa eclipse, you see. I needed to know the actual libration from an off-center point of view on the earth. And the only way in the Almanac normally was very unsatisfactory and difficult.
You had at least one paper on that.
I had two. Because K. Koziee wrote from Poland and said it was no good, or somebody else had done it better or something of the sort, and so I wrote a second paper, and that appeared in the ACTA ASTRONOMICA. 
I don’t recall when that was.
1958. The first paper was fairly soon after Mombasa, more or less contemporaneous. Have you ever seen my paper, by the way, in VISTAS IN ASTRONOMY, Vol. 1.
“An Introduction to the Eclipse Moon.” I very nearly called it, “The Earth’s Seven Different Moons.” Logically they are distinct or were in those days.
Yes. Recently you have been working on corrections for aberration.
I programmed the aberration completely,  because for the Cookson re-analysis I couldn’t work it by hand. I could have punched the whole of the NAUTICAL ALMANAC and interpolated, night by night, and got it that way, but it’s obviously much better to program it. I saw that you don’t have to program the tapes of the sun’s place, though there are tapes of the sun’s place, but there would be far more detail than I’d want. You can simply take Newcomb’s formulae, and use the terms that you want, to calculate where the sun is, (where the earth is, of course), and how fast it’s moving, by differentiating the position-terms, and get the aberration that way. And I programmed it all out, and then compared it, just by hand, every tenth day or something, or fifth day of the ALMANAC. And it agreed very closely; but there was a small systematic difference at times, and I wrote to Wilkins and I got no answer. And I wrote again, I think and I complained to R. C. Duncombe at the Naval Observatory here, that I’d got no answer and didn’t seem able to get any answer. I think he poked him a bit. Anyway, H.P. Wilkins wrote and said, “I think you realize already that we prefer our established methods,” or something of that sort. I’d asked him to explain the difference between his results and mine. But then, T. van Flandern and Duncombe at the Naval Observatory verified what I’d said, confirming that there was an error in the ALMANAC and not in my work, and that it was due to some approximations they’d made. Actually, mine was better than the ALMANAC. I don’t know if they changed them or not. Sooner or later, they’ll have to reapproximate the approximations they’d made, anyway. Then that complete algorithm was useful when I wanted to make an abbreviated, much quicker aberration, for all rough work. Where you don’t apply second order corrections, you needn’t go into all this detail, and it was tested against the other, because I had the program for the other already, so I just took the difference, the one program against the other. It was quite straightforward.
These are the Besselian C’s and D’s? 
Yes. I also suddenly had the bright idea that you could get the radial component by using C and D again with new star constants, to get the correction to radial velocities, for double stars and quasars and things. I wrote a two-page paper on that in the MONTHLY NOTICES.  Of course, it’s very obvious, but I mean, nobody’d done it.
Why do you think that’s the case?
Oh, there are tables that you could use. For correction to the sun.
They just prefer to use the interpolation tables.
Yes, I suppose. I mean, it makes less work. If you’re using the same star a lot, as you are with a quasar or anything like that, I’m sure you could use my way. The star constants change very little in ten years. They only change linearly then. You don’t really have to re-compute them -- if you had them and their rates of change, once, that’s all you ever need. I also upset a traditional view about the Earth’s axis of rotation which had been universally regarded as correct at least since Euler’s day. Two referees turned a first version of my paper down, but I got the Editor to reconsider and publish it.  People still weren’t all convinced and I wrote a back-up (in the M.N. because they did not impose page charges).  I then fought for my view at Grenoble, and the I.A.U. finally adopted it in a formal resolution. Old views die hard all right. But all sorts of things -- they come along, and they’re interesting, and you do them, and then do something else.
What about your non-astronomical interests?
Well, music, of course, as I said before. And I used to cycle a certain amount, and am very interested in touring around, and hiking, to some extent. We’ve hiked quite a bit with our camping. But I have some difficulty with that now. I can walk slowly, for quite a long time, but I can’t walk fast. And I can’t climb much anymore. Our last trip out West was into Bryce Canyon again, Bryce and the North Rim of the Grand Canyon. We did some quite steep climbs in Bryce Canyon. There’s one called the Navajo Loop, down one side of a massif and up the other. I think it’s something like an hour to do it if you’re good, and we did it in 70 minutes or something of that sort, and thought we were fairly good. At our age. A most spectacular run. I don’t garden, by choice. Irmin does.
Well, thank you very much for your time.
I’ll try to fill in some gaps in it.
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