Christian Moller - Session I

Moller:

I am Christian Moller from the Bohr Institute in Nordita.

Weiner:

And we’re sitting in your office at the moment, August 25, 1971. Let me start by summarizing some of the things that I do know, to bring up to the beginning point. I know that you started at the university in 1923.

Moller:

That’s right.

Weiner:

And the first two or three years were at the Technical High School.

Moller:

That is so.

Weiner:

And that you came here, as the usual procedure is, after you began an interest in physics, came here in September, 1926. First Heisenberg was lecturing, and during, that fall Erwin Schrodinger came, and in 1927, after Werner Heisenberg had left, Oskar Klein was giving some lectures.

Moller:

Yes.

Weiner:

That brings me to things that I don‘t know. What was required of you at the Institute, in terms of attendance at lectures? Who else was lecturing?

Moller:

Well, there were lectures by Professor Hansen, H.M. Hansen, who lectured in optics. He was in spectroscopy. And we went through the big book of Drude, and as a matter of fact, I think we had only these lectures of H.M. Hansen and Werner Heisenberg, or Oskar Klein later. Of course Bohr once gave a lecture on quantum theory, but I don’t remember exactly when that was. Maybe it was a little later. Anyhow, it was rather difficult for us to follow. We were still rather young. Later, of course, the most exciting thing was the colloquia, which were held every week, and where all the foreign guests participated and we tried as students to. It was a difficult field at that time, quantum mechanics. I mean, it was so different from what we had learned in the first three years. But certainly that was — we learned most by listening to these colloquia, where Heisenberg and Professor Friedrich Hund was here, and Pasqual Jordan, and, let me see — later George Gamow and Lev Landau, of course, and Rudolf Peierls was here for some time, and Darwin, and Fowler.

Weiner:

One of the things I‘ve done is to compile a list year by year of who was here, which I‘ll have properly typed up and it might be of use to you so I gather from what you‘re saying that part of the teaching was the informal participation, mostly as auditors of the larger discussions.

Moller:

Yes. Of course we also had a more junior type of colloquia where we were supposed to read a paper and report it. I remember the first colloquium I gave was on Louis de Broglie’s thesis, his first paper on wave mechanics, and later I was — this must have been somewhat later — I was reporting Paul Dirac’s paper on the theory of the electron, which nobody else knew at that time, and I remember that Klein and Yoshio Nishina, who were here and who later worked together with Klein on the Klein-Nishina formula, they were much interested in this, and well, to give you an impression about how Bohr was, I can tell you that after the colloquium, he said this was very good, not because — one usually expects because of the things I had understood — but because I had said that this and this point I did not understand. He liked that. Well, later I remember I gave a colloquium on Dirac’s radiation theory, a paper which appeared in the Proceedings of the Royal Society. I think we learned most by being given such topics which we should study carefully by ourselves and try to communicate what we got out of it.

Weiner:

Were they assigned by Bohr?

Moller:

Yes. Yes, by Bohr and Hansen.

Weiner:

Would they be on a rotation basis?

Moller:

Yes. The students all had to, once or twice during the studies here, to give such a colloquium.

Weiner:

You mentioned about three occasions. That would be about normal then?

Moller:

Oh yes. Well, I think I gave some more. You see, we were not so many students at that time. Oh yes, I remember I gave a colloquium on Pietor Zeeman’s experiments on the dependence — I mean, on the relativistic Doppler effect. Sorry, no, on the relativistic — on the old experiment of Armand Fizeau I think, to measure the velocity of light in running water, and Zeeman noticed that if you have a dispersive medium, the effect depends on the frequency, and that it is the frequency in the rest(?) system which is the decisive — I mean, the dependence of N on the diffraction index, on the frequency — in this formula you have to put in the frequency in the rest system of the water. And that is what we checked. I gave a colloquium on that also.

Weiner:

That would have been assigned by Hansen, I guess.

Moller:

Yes, I think that was. I remember that was the time when Heisenberg was here already, so he must have been one of the first.

Weiner:

Was it the custom for the staff — it’s hard to use the appropriate word because some people weren’t necessarily fulltime staff members, nevertheless the senior people — was it the procedure for them to sit in on these student colloquia?

Moller:

Yes. Yes. That was part of their job, I think.

Weiner:

How about Bohr, did he sit in?

Moller:

He was always there, always there.

Weiner:

Was he using the same style of criticism that he used at the colloquia when his colleagues were speaking?

Moller:

Yes. Well, yes. Well, of course, he showed more forbearance with the students. He would not be so critical as he could be in the other colloquia.

Weiner:

As far as these students go, were they all working on theory?

Moller:

No, we worked together with experimental physicists.

Weiner:

You mentioned that the number of students was small. This is something I’ve been to great difficulty in discovering. It’s easy to see who finally got a PhD, and I have a whole list of those, but it’s not at all clear how many candidates were produced.

Moller:

Well, most of them of course went out as teachers in the gymnasia

Weiner:

They didn’t get a PhD, but they did become —

Moller:

They didn’t get a PhD but they became cand. mag., yes. But even the number of those was, compared with today, very small. It was a time of the beginning Depression. There was already considerable unemployment among intellectuals, engineers in particular. It was the time when you saw engineers doing all kinds of jobs. What do we call cranes, no, not cranes, these things were you move heavy things in the harbor — a crane, yes. They worked with these cranes as conductors. And even some of them were selling bananas on the street and so on. So it was a very difficult time, and people in many cases could not afford to go on studying. They went out to take jobs. So the number of students was very small at that time.

Weiner:

What year did you get the cand. mag.?

Moller:

That was in 1929.

Weiner:

Do you recall how many others got it that year?

Moller:

I would say perhaps one or two, very small. I became magister (msg. scientist). That was approximately the same as cand. mag.

Weiner:

Someday I’ll find a list with the names and numbers. It’s hard to do it otherwise.

Moller:

Yes. It must be here in the Institute somehow.

Weiner:

So far I haven’t found it. They are all listed in the university book, but they’re not broken down by subject and it encompasses so many years.

Moller:

Have you talked to Mrs. Schultz?

Weiner:

I talked to her before she left about everything she knew, but I didn’t ask specifically about this.

Moller:

Because I think she wrote down all the protocol at the university.

Weiner:

That’s what I thought, probably in some university administrative office. About the requirements for the cand. mag. or magister, as in your case; how did one finally achieve that status?

Moller:

Well, you had to — in the case of magister, you had to write a small paper. As a matter of fact, I was relieved of this job because I had in the meantime written an article which was handed in to the university, and I got a gold medal for it, and that is a thing we still have, you know. Each year the faculty gives some subject to young people who want to try to solve the problems, and if they are good enough they get a gold medal. So this small thesis was said to be sufficient for the magister, so I didn’t have to write another one.

Weiner:

What was the subject of it?

Moller:

It was on the analogy between mechanics and optics.

Weiner:

A classical theme, then.

Moller:

Yes. Well, it was one of the things which was pointed out by Schrodinger. That was the way he was led to quantum mechanics. So I studied the old papers of Hamilton and then tried to describe the use of this analogy between mechanics and optics, to lead over to the Schrodinger equation. It was more an historical thing, although I contributed a little myself and extended a little the analogy to the case of anisotropic bodies. Hamilton had developed his theory for both cases, but the analogy with mechanics had only been developed for the case where you do not have such anisotropy. So what I did was to extend this. For instance, it’s applicable if you compare with a charged particle in an electromagnetic field — where you also had a magnetic field, it comes in. And I invented a small device to make the treatment of the anisotropic case on the same footing as the isotropic case, by introducing a special metric in the space, which is not the Riemannian metric, but which applies in the case of homogeneous bodies. But a metric which I later found out is called Finsler, the Finsler geometry. I didn’t know anything about Finsler but it turned out that it was an accepted thing.

Weiner:

Who judged the submitted essays?

Moller:

This was Bohr and Klein.

Weiner:

For the entire group?

Moller:

No, no, for the papers in theoretical physics; otherwise, the other professors of the faculty. It’s part of their job too.

Weiner:

What were the other requirements for the attainment of this status? One was the paper.

Moller:

Yes. Then there was an examination, both in experimental physics and in theoretical physics, and Hansen was doing the experimental examination, and Bohr was doing the theoretical.

Weiner:

That means that regardless of your interest and regardless of the subject of your paper, you still had to have both fields, experimental and theoretical.

Moller:

Yes.

Weiner:

That means that somewhere during your training you had to —

Moller:

Do a little of experiments, yes. For instance — one could choose — I did some optical experiments with diffraction of light.

Weiner:

Who supervised that, Hansen, or were there other people?

Moller:

There were also the assistants. There was Jacobsen, the later Professor Jacobsen, and Ebbe Rasmussen. Jacobsen was supervising our course in experimental training.

Weiner:

So it was actually a course, you’d go for several hours at the same time.

Moller:

Yes, and there were some particular experiments you could do. The apparatus was there. It was just to give a little feeling of what experimental physics is. It was not really experimental physics, because we didn’t do anything really ourselves. I mean, it was a prepared thing.

Weiner:

It was using this facility in the use of instruments to know what something looked like, what a measurement was, that kind of practical —

Moller:

Yes. Yes.

Weiner:

The course work itself, you talk of lectures, was that part of the requirement, that you had to attend so many lectures in various subjects? I think you mentioned there was mathematics, physics — that was at the Technical High School — here it was strictly physics, and you mentioned the two lecturers. So you’d go through those courses and then you were expected to —

Moller:

— to read also, to read books —

Weiner:

— and listen at the colloquia.

Moller:

Yes. We had to read quite a lot more than we heard lectures about.

Weiner:

Was some of it assigned reading?

Moller:

Well, we could choose the books according to our interest, more or less, but of course we had to consult the professor if this was suitable for us to read. But otherwise it was rather free.

Weiner:

Would each one have a supervisor, each student has one professor?

Moller:

No. No. Well, actually it was not necessary. We were so few students, I mean. Perhaps I should tell you about my first meeting with Bohr. I don’t know if you have this already.

Weiner:

About reading Einstein in the library?

Moller:

Yes, you know that.

Weiner:

What role did Bohr play in your student days, in addition to his participation in the colloquia?

Moller:

Well, of course, he was extremely kind man. I mean, you could always go to him if you had some problems, and he would always try to help you, and also if there was something you couldn’t quite understand, you knew it was easy to go to him and ask him for advice. But of course he was very busy already then, and although the Institute was small, he did all the administrative work himself, with the help of Mrs. Schultz, that was the whole staff.

Weiner:

So the actual face to face contact was rather limited unless you deliberately made a point to see him.

Moller:

Yes.

Weiner:

How long — it took you I think if my arithmetic’s correct two years?

Moller:

That’s right. All in all my studies took six years. That was normal.

Weiner:

Two for the first step, then four for the PhD.

Moller:

Well, 2-l/2, 2-l/2, the first step and the rest — to get the magister. The doctor’s degree was later. I took the doctor’s degree in ‘32.

Weiner:

Let me ask about the frequency of these colloquia, because I know of two kinds — the ones which were called on the occasion when there were some foreign visitors and the others for lower level students.

Moller:

Yes. The lower level one was once a week. That was regular, once a week. The other one was very irregular, because it depended on, if somebody had something to tell. It was usually when somebody had finished a paper. He would tell about it and then a discussion came up.

Weiner:

The student ones would be a relatively small group?

Moller:

Yes, oh, I think six or seven.

Weiner:

Total attendance?

Moller:

No, I would say, with the staff about ten.

Weiner:

Then I think what I might ask you now — in 1928, before you became magister, I assume you had to make up your mind about what you would do. What were your expectations and desires about that time?

Moller:

Well, at that time I lived in one of the student hostels, the Borch’s Collegium, and I was very happy when Bohr asked me to look through some of his manuscripts — one of them I had to translate into German because he thought I knew German rather well, although I know that my translation was completely changed by Bohr himself.

Weiner:

Not a question of the language, a question of the content.

Moller:

Yes. And so he started to give me a little money. I got 150 kroner a month. And this was the beginning of my connection with the institute, and I hoped of course that I could go on to stay with the Institute. Of course I knew that the chances were not so big. There was not much money, between the university and the Institute at the time, and I was quite prepared that I would have to go out to the gymnasium as a teacher. But fortunately, I got hold of something which became rather interesting, and Bohr was interested in that, and this was of course under the influence of the atmosphere in the Institute, that I got this opportunity. I had written a few papers, not very exciting papers, and then finally I came to this scattering business, scattering of fast electrons. That was actually not before I had taken the magister degree. But rather quickly Bohr was able to supply a little more money for me, and he asked me to start to give some lectures on relativity. That was when I still was at the Borch’s Collegium, so that must have been ‘29, I think. Yes. I talked on special relativity and also on general relativity, and I remember Bohr and Klein sitting there to see how it was going. So finally, when Klein left for Stockholm, when he became a professor at Stockholm, Bohr offered me a lectureship here. Before that I already was what you call an assistant. This gave me 300 kroner a month, I remember — the assistantship did. When I became a lecturer I got all in all 500 kroner.

Weiner:

Do you know the source of the funds?

Moller:

I suppose it was from the Carlsberg Foundation. It was some money Bohr had at his disposal. At least, the assistant money — maybe the lectureship, he got from the university, I don’t know.

Weiner:

I have those figures. So the question of whether you continued for a PhD was decided in a way not only by your promise, which Bohr noticed, but the fact that you became interested in a promising topic.

Moller:

Yes.

Weiner:

I think you mentioned in the discussion with Thomas Kuhn, that it was a remark of Landau’s that put you onto some of the work.

Moller:

That’s right, yes.

Weiner:

I was particularly interested in that because, and you’ve answered it partially already, about the role of the foreign guests in the basic life of the Institute. We usually think of the Institute as providing a place for foreign people to come to work, but we don’t think of the effect of them on the entire educational process.

Moller:

Yes. No, it was absolutely crucial that Landau was here because he — well, first of all, he brought me into the scattering problem — recommended me to read a paper by Hans Bethe. That was the non-relativistic scattering. Then I noticed that the way he had formulated it could be formally at least generalized to relativistic treatment, and I talked with Landau about this, and he said, “Yes, that is fine,” and he remarked that the method which looked very unsymmetrical between the two particles, he remarked that the final result was symmetrical in the two particles. And this gave me great confidence of course in the value of this result. Later, I saw that it was also independent of using, if one used retarded or advanced potentials — that was always a thing that was very much discussed these years. So well, I carried through the work. In the first paper of course there was a mistake, which I had to correct — which nobody discovered, which I corrected in the second paper, in the big paper, which was finally used as my thesis. Of course, my confidence was not so big, that I was really very surprised when Frank Champion experimentally could show that my formula was obviously in better agreement with the experiments he had done than the non-relativistic formula. It was scattering the beta rays going through a Wilson chamber. Of course it was a very crude still, very crude method — but anyhow I was rather surprised that one could, by such a formal generalization, get to something which was really there in nature.

Weiner:

There was no experimental work of that type going on here?

Moller:

No. No.

Weiner:

I think you explained when you talked with Kuhn that you had a letter from Champion but it was unsigned —

Moller:

— that right —

Weiner:

— and then you asked Max Delbruck, who was at Cambridge at the time I guess —

Moller:

He had been in Cambridge. I think he was at Rome at that time, so I wrote to Rome. I have these letters still. He wrote back. He had been in Cambridge when he — I asked him when — since he’d been at Cambridge, I asked him who it might be, and he —

Weiner:

— he suggested Patrick Blackett, perhaps, someone who worked with —

Moller:

Yes, that is what he said. You seem to know more than I.

Weiner:

That’s my job.

Moller:

That’s right.

Weiner:

That’s interesting to me, the fact that Champion wrote to you on the basis of seeing your paper. This is not a question of informal private communication. He’d seen the paper and then communicated.

Moller:

— then he wrote a letter without signing it.

Weiner:

It was very informal. I see. So at that stage anyway there was nothing going on here that would provide confirmation.

Moller:

No. No.

Weiner:

I was going to go on to something else, unless there’s something more on this?

Moller:

No. I don’t think so.

Weiner:

I was going to ask first about Landau, as an example of a foreign visitor who apparently did interact closely with people here. What language did he speak here?

Moller:

I think at that time he spoke mostly German. But he knew English of course perfectly also, and from here he went to England. He stayed a year in Cambridge and made his famous paper on the diamagnetism of electrons. But at that time he spoke mostly German. You know, a number of the younger physicists working here were German. Germany was of course in the ‘20s in a very bad state. I mean, it was just after the First World War and they had the big inflation and so on. Well, it was Heisenberg and Hund I mentioned and Delbruck — Wolfgang Pauli, of course. He had stayed here before I came, had been here a long time. So, many of these colloquia were given in German. It was only after Hitler that we changed over to English completely.

Weiner:

Was this a conscious thing?

Moller:

Oh yes. It was so disgusting to us at that time.

Weiner:

Although at that time you had more Germans than ever.

Moller:

Yes, that’s true, but they were certainly not responsible for what happened in Germany. They were thrown out.

Weiner:

On the PhD, when you did decide to work on it, did you consult with anyone at the institute?

Moller:

Yes. When I wrote the first paper, I think Bohr didn’t know anything about it before it was finished, and I gave it to him. I was a little doubtful what he would say about that. That was the time when Delbruck was here, and I talked with Delbruck about also. They looked at it though and finally Bohr came out and said, “It doesn’t look bad at all.” So he sent it to the Zeitschrift fur Physik.

Weiner:

Was that the procedure — I’m asking now even beyond student days — papers from the Institute would go through a screening process?

Moller:

Oh yes. Bohr read all the papers.

Weiner:

Pre-refereed them.

Moller:

Yes. And very often he gave advice on how to change the manuscript and so on. Oh yes, he was very careful.

Weiner:

So you said the first time he was aware of the work and got involved was when he saw the first paper. Otherwise it was pretty much working on your own.

Moller:

Yes. Well, this was also a little in my style. You know, I’ve never been working very much together with others. As a matter of fact, I’ve only worked in my life together with, I mean really worked together with Leon Rosenfeld. Let me see — with Plesset, I wrote a paper with Plesset.

Weiner:

In 1934.

Moller:

Yes. And —

Weiner:

— you wrote a paper with Felix Bloch.

Moller:

Yes, with Bloch, that’s right. That was when I was at Cambridge. Well, you know all that. You see, some people very very quickly come into conflict with other people. I talk with them and so on, but I mostly talk with them after I have finished something.

Weiner:

During that period, prior to 1932, ‘28 to ‘32, you were an assistant at first (throughout you were an assistant) which meant assisting Bohr?

Moller:

Oh yes. I had sometimes to help. But I must say it was more in name, assistant, because there was not very much to assist. After all, Bohr had quite a number of people. Klein wrote everything down that Bohr was saying all the time he was there. Also this — I’m not sure I’m so good at that, because I get terribly tired if I have to listen all the time and write. Bohr accepted that very kindly, so that many other people have worked more intimately with Bohr than I have.

Weiner:

In addition to this vague assistance, you had specific lecturing?

Moller:

Yes, I had to give lectures. I took over the lectures of Klein when he left, and I started a little before with this lecture on relativity, as I mentioned before. Then I took over the lectures on electrodynamics and statistical mechanics and classical mechanics, and also theory of elasticity, all these, thermodynamics, all these classical subjects.

Weiner:

So your counterpart was Hansen.

Moller:

That’s right.

Weiner:

How long did that continue?

Moller:

Well, I continued all the time. Then I went on giving lectures. But, Hansen yes, Hansen also, through the ‘30s, all the time through the ‘30s. Then also Jacobsen and Rasmussen started to give lectures in experimental physics.

Weiner:

On what sort of thing?

Moller:

Well, Jacobsen took over some of the things Hansen had been lecturing in. For instance, he took over what is now called electronics. There was a book by Crowther I think, that was the basis. Rasmussen took over the lectures on optics. He also gave special lectures on spectroscopy. Rasmussen was a spectroscopist.

Weiner:

Was there anything in radioactivity?

Moller:

Oh yes, that was what Jacobsen took over. Oh yes.

Weiner:

Getting to the PhD examination, once it was written up, I know there are some procedures. What was the procedure in your case?

Moller:

The procedure was in this case that after this first paper on the scattering of fast electrons, when I came back after my honeymoon journey in the summer of 1931, I said to Bohr, “Wouldn’t it be interesting to try to continue this and calculate the stopping phenomenon of relativistic particles?” That was of course a subject in which Bohr was a specialist, because he had also from the point of view of classical mechanics done this famous work already, in 1913, I think, simultaneously with the famous papers on the constitution, of the hydrogen atom. So yes, he said, that would be very good, and I finished this during the fall of 1931, more or less, and wrote it up for a paper to the Annalen der Physik, and since I was not very wealthy and it was a rather expensive thing to write a thesis, Bohr managed to get this paper in the Annalen der Physik recognized as a thesis. I then only had to write a Danish survey of what was contained in this paper, and I did that, and these two things were coupled together and formed the thesis.

Weiner:

I did find a letter in the archives. I think you were in Nordsjolland somewhere writing this introduction.

Moller:

Yes. Well, that is the island where I was born, so I work in the summer always there.

Weiner:

Then what was the procedure at the university? Did it have to be circulated?

Moller:

Yes, it was sent in to the faculty and it would be judged. The faculty would appoint two professors to look through the thing and see if it could be accepted.

Weiner:

Were they known to you, the two?

Moller:

No. Well, I don’t remember — of course Bohr must have been one of them. Probably Bohr and Hansen, I think.

Weiner:

Really what I’m getting at: was there any confrontation, any kind of defense of the thesis?

Moller:

Oh yes. Oh yes. After that, that was the usual procedure and still is, that two opponents have to try to attack, at an official defense, and that was Bohr and Klein, who was then professor in Stockholm but he came down. Well, that was just the usual procedure.

Weiner:

You say opponents?

Moller:

Well, their job is to try to find a weak point and ask the defender what he says to this and this and so on.

Weiner:

Was there any difficulty, embarrassment or confusion?

Moller:

Well, Bohr actually gave a lecture, I must say, more or less. Well, I remember one thing that was more or less a joke. I had used the word “classical” treatment, as we usually do if it is not quantum mechanics, we say classical, and he asked, “Do you know what the word classical means?” Then I said, “Yes, I know what it means, but I think in physics we more or less use the word for everything which is a little older than the thing we just are interested in now.” No, the only serious thing which was mentioned by Klein was something which he didn‘t find quite clear. I said at some point that it did not matter if we used retarded potentials in the solution or advanced potentials or the mean measure between these two, and he said he didn’t quite see that. Then I tried to — well, it was only mentioned there and I hadn‘t elaborated in the paper, so I explained why I thought it was so. Then he was satisfied.

Weiner:

Who else was present?

Moller:

Well, everybody can go there, you know. Who was present? Hansen was there of course, and the younger physicists, Jacobsen and Jorgen Boggild.

Weiner:

About how many in all?

Moller:

Oh, I would say 30 or so, 30 persons I would think.

Weiner:

Were they all from physics, or people from other parts of the university?

Moller:

No, they were mostly physicists. I would think so.

Weiner:

There certainly weren’t that many on the staff; were there visitors?

Moller:

No, but maybe some teachers from the gymnasium and so on. People at the gymnasium here are interested in following these things. And then of course the press is usually there also.

Weiner:

I was really interested in that. I found a scrapbook of Niels Bohr’s dissertation as cartoons showing himself defending and so forth. I wondered if it was because of his fame or because of his father and so forth, or whether they did that anyway?

Moller:

No, this is usual.

Weiner:

There is a little article in the newspaper?

Moller:

Yes. They say a little about it. They usually don’t know really what was going on, but they try to describe some of it.

Weiner:

Describe the personalities, the drama.

Moller:

Yes, and there is usually a cartoonist from one of the papers, draws a picture of the people, the opponents and of the defender, yes.

Weiner:

Did that keep up through the ‘30s? I imagine it would be difficult.

Moller:

Oh yes. It’s still going on. Oh yes.

Weiner:

That means they’re not given on any particular date. They’re probably staggered through the year.

Moller:

Yes. It is usually on a Thursday. I remember, on the Thursday I was supposed to have this, there was another one, a medical man who also became a doctor. So this act was not at the usual place, which is at the university, but it was in Hansen’s Institute over here, the Krogh’s Institute as we usually call it, the zoo physiology laboratory.

Weiner:

It wasn’t Hansen’s, wasn’t it Krogh’s Institute?

Moller:

Yes, August Krogh was there also, but Hansen had become professor of biophysics, so therefore he had his laboratory there.

Weiner:

That was in 1932.

Moller:

That was in 1932, yes. It was newly built then. Now it is deserted again, because they have moved over on the other side of Norrealle.

Weiner:

Once you were awarded the doctorate, then did you remain in the same position? You did the same thing but was there any change in your title?

Moller:

No, I went on as a lecturer at the Bohr Institute until 1940, when I became what they called docent. The lectureship is connected with the Bohr Institute, and docent is connected with the university, which was a form for a professor. I think you would call it associate professor, something like that. In 1943 I became a full professor then.

Weiner:

That was the year you were also elected to the Royal Danish Academy.

Moller:

That’s right. That was the same year, yes, 1943, But it didn’t change my life at all, because I stayed on here, After all, the Bohr Institute was a part of the university.

Weiner:

Prior to that time you had no university appointment, no responsibility in the sense of the university, and the funds probably came from the Institute.