Notice: We are in the process of migrating Oral History Interview metadata to this new version of our website.
During this migration, the following fields associated with interviews may be incomplete: Institutions, Additional Persons, and Subjects. Our Browse Subjects feature is also affected by this migration.
We encourage researchers to utilize the full-text search on this page to navigate our oral histories or to use our catalog to locate oral history interviews by keyword.
Please contact [email protected] with any feedback.
This transcript may not be quoted, reproduced or redistributed in whole or in part by any means except with the written permission of the American Institute of Physics.
This transcript is based on a tape-recorded interview deposited at the Center for History of Physics of the American Institute of Physics. The AIP's interviews have generally been transcribed from tape, edited by the interviewer for clarity, and then further edited by the interviewee. If this interview is important to you, you should consult earlier versions of the transcript or listen to the original tape. For many interviews, the AIP retains substantial files with further information about the interviewee and the interview itself. Please contact us for information about accessing these materials.
Please bear in mind that: 1) This material is a transcript of the spoken word rather than a literary product; 2) An interview must be read with the awareness that different people's memories about an event will often differ, and that memories can change with time for many reasons including subsequent experiences, interactions with others, and one's feelings about an event. Disclaimer: This transcript was scanned from a typescript, introducing occasional spelling errors. The original typescript is available.
In footnotes or endnotes please cite AIP interviews like this:
Interview of John H. Van Vleck by Charles Weiner on 1973 January 19,
Niels Bohr Library & Archives, American Institute of Physics,
College Park, MD USA,
For multiple citations, "AIP" is the preferred abbreviation for the location.
Developments in quantum mechanics, familiarity with the old quantum theory; Edwin C. Kemble is his thesis advisor at Harvard University, 1920-1922. Comparison of Harvard and University of Wisconsin; work and collaboration with graduate students and postdocs at. Wisconsin. Research work in Europe, 1926 and after; high-frequency paramagnetism. Paramagnetic anisotropy. Teaching at University of Michigan, Stanford University, Columbia University, and Harvard University; 1930 Solvay Congress; discussions of research work and papers, 1920s-1940s; awareness of the development of solid state physics; Linus Pauling and the ligand field theory; teaching responsibilities. War work at the Radio Research Laboratory at Harvard as head of the Theory Group; the many duties on advising and reviewing committees during World War II. Chairman of Physics Department at Harvard, 1945-1949; chairmanships and other official functions during the 1950s, excitement of the renewed interest in ligand field theory (chemists); comments on personal interests.
This is a long-overdue continuation of earlier sessions with Professor Van Vleck many years ago, which we had taken through the 1930's. It's our intention to pick up from there and get into the 'forties.
Let me start off by asking a question about how you first became involved in war work. What were the processes? Who talked with you? What were you aware of in terms of what others were doing? When did all this happen?
My war work essentially was mainly at the Radio Research Laboratory (located at Harvard) which was concerned with radar countermeasures. But in the period around 1941, just before the war and just after its outbreak, there began to be a concentration of physicists at MIT, called the Radiation Laboratory. I was anxious to be cleared for that. It took quite a while. By the time I was cleared, I pretty much had become involved with the Radio Research Lab, plus the summer I spent in Berkeley with the theoretical group which later was identified with the Manhattan Project but was not so known at that time.
One of my best contributions, I think, during the war, was the observation of the fact that there would be absorption of microwaves at a half centimeter, due to oxygen, and at about a centimeter and a quarter, due to water vapor. The reason I got started on that whole question was a curious one. Harry Mimno, my colleague at Harvard, gave me a paper by someone whose name I don't remember, to look at, which claimed that there would be absorption due to the oscillation of molecules in the earth's electric field. It was a completely nonsensical paper. The author didn't know enough quantum mechanics to realize that there was such a thing as zero point energy and so on. It was complete balderdash. But that got me started thinking as to what would cause absorption of microwaves, and I remembered some calculations that Schlapp had made at Wisconsin on certain lines in the molecular spectrum of oxygen, which was a refinement of some earlier work of Kramer's. Consequently I realized that there could be some absorption at around half a centimeter due to oxygen.
If they tried to use radar at that wavelength, the radar would be very ineffective. The radar was getting to progressively shorter wavelengths. In the closing days of the war it got down to a centimeter. I'd say that one of my contributions was to show that at some wavelengths they might have tried, had the war lasted still longer, the radar wouldn't have worked; that was the oxygen thing. The other was on absorption due to water vapor. I combed through all the Michigan data, and discovered that there was one transition that was allowed by the selection principle that would fall somewhere between a centimeter and a centimeter and a half. I took the difference, given in the original experimental paper. A little later Dennison gave a little different value, that corresponded more nearly to what was actually the correct wavelength. I think you know the story, that when they got the so-called K-band constructed, it fell almost exactly on top of the water line. I didn't know exactly where it was located and nobody else did. En route to Chicago to visit the "Metallurgy Lab" there, I stopped off at Ann Arbor on a sub-zero day and talked to Dennison for two or three hours. But I never learned that there were two different estimates, of which the latter was the better. He simply said that the line could be anywhere between a centimeter and a centimeter and a half.
I facetiously said in one of my talks that I contributed to the research effort of the Clarendon Laboratory of Oxford after the war, because if I had urged the Radiation Lab people to take my paper a little bit more seriously and try to go all out to examine where that water vapor line was located, they wouldn't have had all this surplus K-band equipment, which gave the Clarendon Laboratory a big boost right after the war. I was always amused at this aspect.
How was it they came to get the surplus equipment?
I know nothing about that. That's experimental physics, outside of my ken.
I know, before the war they were desperately in need of funds and equipment and I was wondering how the transfer was made, but that's something I can look into with Kurti when I talk with him.
— yes, he would be good to talk to or Bleany might be still better.
Let me backtrack a minute. You said you were waiting for clearance to get involved in the MIT Radiation Lab, which was meant to develop radar. Was there someone who had specifically approached you to join?
I don't know about that. I couldn't say. I thought I'd like to be in on what I could do in the way of helping. I think I can say, with a very good conscience, that the reports that I published for the Radiation Lab cost less per report than any other reports they put out. I obtained computing help by asking a girl at Harvard  by the name of Eleanor Dupré, and the total bill was $12. It led to two reports. I was never a salaried member at MIT. After the war I got a letter from Wheeler Loomis saying that they would pay my carfare home first class. But they did make my wife a life member of the MIT Bridge Club, so there was one fringe benefit anyway.
How long were you involved there before you got involved in the Harvard effort?
Well, see, the point was that the people in the Radio Research Lab who were concerned with radar counter-measures had free access to MIT. It was a semi-permeable membrane. The people from the Radiation Lab could not have access to the Radio Research Lab without special clearance. But as to this whole question of absorption of the oxygen and water, as I remember it, those reports came out before the fall of 1942, when I was put half-time on the salary budget of the Radio Research Lab and half-time continued my duties at Harvard. That was my fiscal setup beginning with the fall of 1942.
At the Radio Research Lab my efforts were concerned to a very considerable extent with signal-to-noise problems connected with the jamming of radar and so on. I benefited very much by contact with Steve Rice of the Bell Telephone Laboratory. I don't think they were appreciative of what a fine report he had written. I told Uhlenbeck about it, who was head of the theory group at Radiation Lab. He was quite excited. We invited Rice to come up and give us a talk at a colloquium there, and I wrote Buckley  what a fine piece of work Rice had done. I hope it helped a little in getting him some of the recognition that his work so richly deserved.
Who was the head of the Harvard Radio Research Labs that you worked with? You were head of the theoretical...
I was head of the theoretical group. Fred Terman was head of the laboratory.
I know nothing about him.
He was an engineer from Stanford who later became Provost at Stanford. He's had a distinguished administrative career. He's author of a well known handbook on vacuum tube circuits or something of the kind, I wouldn't know exactly.
When you joined the project at Harvard, was it your assignment, to develop a theoretical group, or was the group already in existence?
I would say I pretty much developed it, except for one exception, namely, there was a group concerned with the thin metallic strips that are dropped to foil enemy radar, the thing that the German children used to decorate their Christmas tree with. That was run by Fred Whipple, an astronomer, and was technically attached to the theoretical section. I always felt it should be a separate section, but it was not so ruled. In consequence technically that area of research was in my group, but actually it had pretty much autonomy.
You worked on that yourself with Felix Bloch.
Yes, Felix Bloch and I, that's correct, we did write one paper together with Melba Phillips and Hamermesh and we looked a little bit into those problems.
That was published in the postwar period, 1947 I guess.
Right. The paper on clipped noise that Dave Middleton and I put out a report on was also declassified after the war: So many requests for copies kept coming in over the years that we finally had it published in the Transactions of the IEEE, slightly updated. That was one of the more important of my contributions, I think, in the signal-to-noise field, in fact perhaps the most important one.
Who was in the theoretical group?
Well, Morty Hamermesh was a key figure. He was recommended to me by Felix Bloch. That's how I first became acquainted with him. And later on he became head of the Document Room. Bob Sard at one time was head of the Document Room, before he went to the Philippines or something of the kind, and I don't remember whether he was attached at all to the theory group. Dave Middleton was more or less my personal research assistant. Felix Bloch was in the group. I think he was happy to come from Los Alamos to Cambridge; Eugene Fubini, and Melba Phillips were also in the group. So were Sutro and Bob Weinstock. Those are some of the people that I can think of.
There are some accounts of the wartime development that can probably fill in the facts, the OSRD reports, for the exact personnel. What about the way the group functioned? Did you all work together on the same problem, or did you assign pieces of a problem?
A little bit more the latter, I think, than the former. Perhaps we should have had more colloquia than we did. I think finally Felix said we ought to have a colloquium once in a while on activities of the group. We worked on a pretty informal basis. I convinced the personnel department that the theorists were peculiar animals and they shouldn't necessarily arrive at 8:30 and leave at 5, provided they worked the requisite number of hours. So on our time sheets we entered when we worked, and occasionally we were allowed to take classified documents home and work there on those. So I succeeded in getting somewhat more freedom in the research scheduling of the theorists than was the case for the experimentalists.
What was the link between the theory group and the experimentalists?
Occasionally an experimentalist would come up with a particular problem that he had in mind. I would say that the link on the whole was not too immediate. But still I feel that the theory group did make some worthwhile contributions that perhaps had some long-range influence on the design of equipment, perhaps more scientifically than militarily, I don't know.
You mean you weren't working on some specific thing in tandem with the experimentalists?
Oh, we were sometimes. We were asked what was the best design for a search receiver, i.e. something to pick up an enemy signal, which we assumed had pulses. We wrote a paper on that, Dave Middleton and myself. It showed the idea that the optimum shape of your filter was the Fourier transform, a complex Fourier transform, of the pulse — regarded as a function of time. This idea we did not claim was original with us. We picked it up from conversations with Henry Wollman. I think Norbert Wiener also had the same idea. Within the last year or two, I had a letter from the patent department of the Department of Justice. They were trying to contest somebody who claimed that the idea that the optimum filter as a Fourier transform of the pulse was something that they had patented back in the later 'forties or something of the kind. The question was, whether the Justice Department could establish that this was a matter of common knowledge prior to then. And I think we furnished a pretty good case to this effect.
Because of the fact that you picked it up, for example.
Yes, it was mentioned in our report. Of course it was classified at the time.
During this period at the Radio Research Laboratory, were you relieved of all teaching duties?
No, I was half time at Harvard and gave one course, and the other half of my existence I spent at the Radio Research Lab. Except that I suspect that more than half of my effort went into RRL at one time. However in the very closing days of my career at RRL it perhaps went the other way, because I was becoming departmental chairman and there was an awful lot of administrative work, so I had to quit RRL.
Was the course connected with some wartime training or was it a normal physics course?
I would say that the courses were pretty much normal courses. I would say that prior to my going to the Radio Research Lab, I carried on some elementary courses in electricity that were definitely pointing towards the more radio-oriented courses. My teaching contributions in connection with war work were rather more prior to September, '42 than thereafter, but I did give courses in mechanics. Courses like group theory were more or less scratched for the duration except when we came to the summer of 1945, when people were beginning to be demobilized, and it was proper to try and put science back on its feet.
You mentioned that prior to your involvement at the Radio Research Lab you went out to Berkeley in the theory group that eventually worked into the Los Alamos project.
That is correct, and there's an amusing thing in that. There was a telegram that came from Arthur Compton, directed to my father, who is also a member of the National Academy, saying "Would you accept membership on a committee to study the feasibility of uranium fission?" It's interesting, a telegram like that would just go right through the wires in those days. We weren't even in the war at that time. But it was obviously intended for me. They'd gotten the initials mixed up. And if you look at the Smyth Report you'll see that I served on an advisory committee of the National Academy of Sciences that recommended strongly that funds be given to the group of Fermi, Szilard and some of the other people, to try and get a little more nuclear data. We said, "They ought to have $10,000" or something like that. The figures were minuscule, compared to what the ultimate cost of the Manhattan Project was. Our committee did back very strongly the fact that we should look into the possibility of uranium fission. Of course, cross-sections and so on were still uncertain at that time. It was not yet known whether what happened on December 2, 1942, 1 think I've got the date right, was sure to take place.
Was there any resistance or opposition within the committee to this decision?
I don't think so. No, I don't remember any opposition. There was a little worry at one time, whether if you got bombs of too much TNT power they would lose their effectiveness in comparison with the weight, if you know what I mean. I think that was a little overplayed as a possible objection.
As early as that time?
Yes. I remember reading the accounts of the Halifax explosion and so on. A boat exploded then during World War I with a couple of thousand tons of TNT in it.
Were there any doubts regarding the fact that both Fermi and Szilard were Europeans, security questions that might have been raised at that time?
I think on the whole that there was very little worry by those in the know. One time I went to Washington to try to get some documents for Oppenheimer, who was then affiliated with the Metallurgy Lab at Chicago, and Briggs wouldn't let them be sent to Oppenheimer because Briggs said he was not cleared. So I sent them instead to Arthur Compton, and I remember sitting down at the railroad station in Washington and writing Compton a letter saying I thought it would be an unmitigated catastrophe if Oppenheimer were not cleared and so was not in on the uranium fission business. Breit was ultra- security minded at the Metallurgy Laboratory and I think he was the person most apt to question the clearance of some of these people from abroad. I think he was absolutely honest in his convictions but I believe they were overly drastic.
When you were out on the West Coast, after this National Academy meeting —
— Yes, that's quite a bit later —
How did that come about? Were you invited there?
Oppenheimer convinced Compton that working conditions for theorists in the summer were better at Berkeley than at Chicago. That's why I went to Berkeley.
You had not been involved at Chicago?
Only loosely. We'd had occasional committee meetings and I was asked to look into certain questions, which I'm afraid I didn't get around to because of other things pressing me. But did go out to Berkeley for the summer of '42. It was a very distinguished group. But I was not a nuclear physicist and I don't feel that my contributions there were as good as my contributions in connection with Radiation Lab and Radio Research Lab, for which I had a better background.
That was the summer that Bethe came out?
Hans Bethe, yes. I recruited Bethe for that project, when he was at the MIT Radiation Lab. I called him and said I thought a good place for conversation was the Harvard Yard. So we sat down in the middle of Harvard Yard and I tried to tell him what I could about the project and still not violate what were the security rules. I had a code arranged with Oppenheimer, if I sent him a kiddygram on his train going to Berkeley, it meant that Bethe agreed to join the project. So Oppenheimer received some kind of a statement to "brush your teeth" and so on. It meant that Bethe was coming. It was inexpensive and it also satisfied all the security rules.
This whole period you're talking about, around 1940, '41 — you were beginning to do some work after 1941 for the MIT Radiation Lab
Yes, that started about '41, as remember .
The Conference on Applied Nuclear Physics was October, '41, and it was at that conference that DuBridge started pulling people together for the laboratory that opened soon after.
Well, maybe it was later than I thought it was; for my reports for the RL I can try and look the dates up
It may have been early '42.
It may have been early '42.
You continued on this National Academy Uranium Fission Committee essentially until when?
That committee more or less passed out of existence because the thing that we had plugged for, namely, some interest in the question of uranium fission, had gotten proper backing from the people higher up. So our committee was no longer needed. We were not specialists, by and large. I don't think Coolidge or Slater or I were particularly nuclear physicists. So that was purely an advisory committee. In the spring, I think, of 1943, I may have the period wrong, I was on a reviewing committee for General Groves to go out to Los Alamos and make a survey. We turned in a report that Oppenheimer was doing a superlative job as director. I think he did handle the people there well. The chairman of that committee was Tolman.
Was that your only subsequent involvement with the Manhattan Project, once you'd started at Radio Research Laboratory?
Pretty much. I may have dropped in at the Metallurgy Lab from time to time. Compton said he'd be glad to have me. But I would say that what you say is substantially true.
Were you pretty much in Cambridge or did you commute a lot to Washington in connection with the Harvard Radio Research Lab?
Occasionally. But that work was pretty much done here. Dave Middleton and I went down to RCA, to talk to North who was a very good noise man in connection with our signal-to-noise problems. We talked to people at Bell Lab, with an occasional colloquium in Washington. I remember Hamermesh and myself going down for one. There were some other occasional Washington things, but I was not a regular commuter on the Federal at all.
Were you aware of the work being done by some of the semiconductor research group?
No. scarcely knew what a semi-conductor was at that time.
So you weren't concerned with materials.
No, we weren't concerned at all with materials.
Some of that was going on either at MIT or related laboratories, Purdue, Pennsylvania, DuPont.
Yes, Purdue think did a good deal.
I guess I touched on that recently, looking into the transistor story, and I wondered. You mentioned that toward the end of the period you were beginning to spend more time in academic educational things and less in the Radio Research Laboratory.
That was, I'd say, after the collapse of Germany, when we were still at war with Japan. In fact, even in late '44 we were beginning to feel that they should begin to start winding down the laboratory. We'd heard (by that time Paris had fallen) that the Luftwaffe was pretty well beaten down, so it was just a question of time before Germany collapsed.
When can you date the beginning of concern regarding the postwar development of physics work at Harvard, perhaps even nationally? I know some of these discussions took place with people while the war was still going on, because it had become apparent to them
Well, I don't remember anything really formal about that. I just drifted into my old academic pursuits, except I became chairman.
Well, when did the first inklings of the chairmanship come to you? When were you approached? When did you think it might be a reality? This has to be during the war, the approach was made.
Oh, 1945. I believe Kemble quit as chairman when he went over to work with the Alsos mission, isn't that right?
I'm not sure.
Or maybe I was only acting chairman, but I think he released the chairmanship at that time and I took it over, and the mathematics department was so decimated that for a while I was acting chairman of that department, so I was chairman of two departments at once. That was a very short period. That was a period when faculties were down to mere skeleton size, so that was not too much of a chore.
Was there any discussion of the postwar readjustment that would have to take place? I'm sure that there were discussions as to the readjustment which was taking place, but was there any overall plan that was developed when you came in as chairman?
I can't remember any. It seems to me Paul Buck had the idea of some kind of a moratorium between the termination of summer school in '45 and when the university would open. I can't remember. I do remember a meeting of the Coffin Fellowship committee of General Electric during the war which I went down to. They were going to try to spend all their (annual) fellowship money and I said, "This is silly, there are no physicists available that need fellowship help, unless they're non-clearable foreigners or something of the kind." I suggested that they salt this down and have it available after the war. So I think they didn't spend all their full budget. They were surprised that a member of the committee would sound this note, but I think it was the only sensible thing to do at that time.
Were there expectations of increased funding after the war, because of the demonstrated significance of physics during the war?
There probably were, in certain groups. Not being an experimentalist, I was not very conscious of or concerned with those things. But I remember Gilbert King saying the Navy was trying to spend a lot of money on research and Harvard had better get in on it.
Who was Gilbert King?
He was a physicist with Arthur D. Little. I don't know what's happened to him.
Was he connected with ONR in the postwar period?
I don't know.
That's an interesting story, the ONR story in itself.
Yes. I know very little. I was never much of an operator so I don't know much about these things.
How did that intrude during the period of your chairmanship? You had some responsibility — I assume the cyclotron came under your department, the question of accelerators —
— that belongs to the business of the Director of the Laboratory. We have a wonderful setup at Harvard. We have a Director of the Laboratory and we have a Departmental Chairman. Anything that concerns apparatus for a cyclotron, was a question for the director.
Including the raising of funds for staffing and so forth?
Yes, pretty much. You might have to go over my desk, but there was pretty complete autonomy.
How would you characterize the main duties as chairman during the period you served, '45 to '49?
I would say mainly to get a good staff, and a distinguished faculty, also to see that the courses were adequately manned, enough courses given and new courses as needed. I would say that those were the principal duties.
Was there a deliberate attempt to have a balance in the fields of physics represented, or desire to focus on certain specific fields where you thought it would be appropriate to develop?
We had only a limited number of permanent chairs, and I think the general feeling was to get the best man we possibly could. When we got people like Purcell, Ramsey and Schwinger, I don't think we made any mistakes.
But in the case of all three of them, there was no consideration of building up strength? You can want distinguished men and still decide to take them from specific fields to develop -
I don't think there was too much concentration on fields as such.
How about in presentation of courses? There are some assumptions about what undergraduate and graduate education means, in terms of what the Harvard physics department standards are, but I'd assume there would have to be a balance in the course offerings. Wouldn't this in some way influence the kind of faculty?
Well, I don't think any of the permanent appointments were made in that era primarily just to man the elementary courses. But there was a man by the name of Gerald Holton who was phenomenally successful in his elementary teaching, and Paul Buck did decide that there could be an additional post available for a man of this sort. As you know, his work is partly in history of science. So he was essentially an extra-quota appointment. At Harvard we had the so-called Graustein plan, which stated that there was a permanency coming vacant every so often.
There was no expansion of this in the immediate postwar period?
We did get an additional post because Bainbridge was very impressed with the work of R. R. Wilson, out at Los Alamos. Bridgman and Conant at that time were both living in Randolph (N.H.) and Bridgman secured from Conant the agreement to an additional permanency in the physics department. As I look backward, perhaps I wasn't as aggressive as I should have been in trying to expand our department during this period. Anyway we did have this one additional appointment, and that additional appointment after Wilson left for Cornell was filled by Ramsey.
To be more aggressive would have been to obtain funds?
It meant to badger the administration about how important physics was and so on. I'm not that sort of person.
Among the experimental physicists, the medical physics work (or interest at least) had been developing, certainly at MIT and somewhat in connection with the cyclotron at Harvard. Was that of any significance during the period that you were chairman?
I don't think so, because our old cyclotron during the war was appropriated for Los Alamos. There was a new one built after the war, but it was a while before it became operative.
There were some interesting letters that Lawrence wrote people at Harvard, urging them not to worry about that old one, to go after a much, much bigger one.
Yes, I know, there was a lot of discussion of that kind, some alterations in design as the thing was being built. I think that's substantially true.
What I'm trying to do is establish the social setting, some of it relating directly to work, some not at all, but it gives me a better view of it. When you picked up your research interests in the postwar period, I know that the experience you had with microwave devices was significant, and that some of the work that you had done during the war began to be declassified and you were able to publish it. But would you characterize the years from '45, let's say, to about '49 as a period in which you were finishing off things that either you had had in progress prior to the war or that you'd developed during the war?
I'd say that during that period I was awfully busy as departmental chairman, and that several of the reports that I put out during the war, either alone or in collaboration, were written up for the various journals, Physical Review has the oxygen and water paper.
A lot of the microwave papers came out in that period.
Study of the relative efficiency of aural and visual detection, (search receivers) that was made into a paper by Middleton and myself in the IEEE, I guess.
No, the Journal of Applied Physics.
That apparently was a useful paper. The engineering groups that had worked in problems of that sort were not the groups with which I had customarily been working, so that my knowledge of the impact of that paper on that group comes in only a rather vicarious way. There's quite a cleavage between my radio research type of work and my traditional work, in that Planck's constant h is not involved in any way in those signal-to-noise problems. Of course it was in the oxygen and water absorption.
But it wasn't a period for you when you started in any brand new fields. You rather saw opportunities.
That's right. I've always been a pragmatist, I should say. About that time Purcell got me interested in problems of line shape and nuclear magnetic resonance, so that I developed a paper using the method of moments, which has been very extensively used. It was really based on an earlier paper of Waller, for which I feel he has never been given proper credit. I certainly did in my paper.
What was your pattern of collaboration in this postwar period? I would think that as departmental chairman, as the senior man in the department, you'd be developing a number of collaborators including students.
I had some students. That is perfectly true, I had research students during this period. I essentially collaborated with Purcell on this question of line shape. Our publications appeared adjacently but with separate authors.
For example, in 1950 when you collaborated with Kuhn, was this something that grew out of his work, something that he was pursuing on his own?
No, this idea of using the quantum defect method was an idea that occurred to me when I was lying in bed at night during the war. But there was no time to work on it, and when the war was over and a thesis topic was needed, I gave it to Tom. I think that's a fair statement.
Had some other problem that you'd been thinking about led you to this, or was it a question of filling a blank space?
I was mulling over the Wigner-Seitz paper on the solid state, and I began to wonder, "Well, all you need is the exterior parts of the atom." Then I remembered Bohr's old derivation of the Rydberg formula and I thought, well, why couldn't that be used in connection with solid state physics?
So it's really an idea of taking work that was known and applying it to a new area.
Which is one of your strengths.
Of course the quantum defect method had to be modified, because the boundary conditions were different. The atom doesn't extend out to infinity. Instead you have your solid-state boundary conditions. Some people say that method is cheating because it uses the observed spectroscopic quantum defects, but the same thing is true of the selfconsistent fields, where they try to fit the spectroscopic terms. Either one is tailored to spectroscopic data. It's an extrapolation from spectroscopic data of the free ions to certain conclusions regarding cohesive binding energies.
Let me, ask questions in general about magnetism, in terms of the field jelling on an international scale — by this I mean, to the point where there are again international conferences on the subject. The Amsterdam Conference in 1948 is not exactly the Solvay meeting that you went to in 1930, which was magnetism.
Do you know something about the origins of that Amsterdam meeting, what led to it? Was it because there were problems that had come to the fore?
Because the Dutch were very good in magnetism. They wanted rapport with the outside world, and I think they also felt that this was a timely field on which to have a conference. I think those various factors worked together.
There wasn't a specific theoretical or experimental development that prompted the need for discussion?
No, not that I know of. Of course, this whole field of microwave spectroscopy burgeoned after the war. There were two conferences in Holland, one in '48, one in '50. I have a little difficulty keeping them straight.
I thought '48 was magnetism but I can't say for sure.
The '50 was very largely magnetism, but I don't know the precise boundary conditions.
On the '48 conference, was this the first time you had been back to Europe since the war?
Yes, the first time since the war was in '48, very definitely.
What was your impression, were you able to get an impression of physics research at least in the field you knew best?
Well, I think Leyden had a good group and they were conscious of the fact. And the Clarendon Laboratory had a very good group. I would say that they were coming to the fore, also the group at Grenoble.
Well, Leyden and Clarendon were two of the main centers of low temperature work.
That's true also.
I'm thinking of the tremendous investment one has to make in large scale apparatus and so forth — was it difficult for the Dutch to rebuild after the war? I don't know if any of it was destroyed or not but I imagine it was relatively inactive for a period of time.
am not an expert on that. You should interview Bloombergen.
OK, that's the name I was looking for. I have talked with Casimir about some of this.
Casimir, and Goudsmit, of course.
He would have kept in touch, but wouldn't have first hand knowledge. Well, at those conferences were there any results that were stimulated by the conferences? I distinguish between different kinds of conferences. Some are really fertile because they stimulate people. They open up new ideas.
I can't think of any. I don't like to be categorical.
I'm assuming there are some Proceedings.
I think so, yes. I'll look over them. I think I wrote up a paper for both of them.
Well, we can tell — let's see, '48 — I don't see it in the Proceedings. In your publications they're just normal journals, not Proceedings volumes. This is '47, that goes up through the forties.
No. 81, by the way, "Multiplet Intensities for the Nebular Lines," was largely the result of Ufford's being here during the war to teach. He was a conscientious objector to military work, but he did teach and got me interested in this problem. No. 82 was essentially connected with the '48 conference. And 87 was the Grenoble conference, I think.
What year was that?
1950. There was also "Ferromagnetic Resonance" in PHYSICA that was the 1950 conference in Leyden. There were two conferences that year, one was in Grenoble and one was in Holland. The Proceedings were incorporated as in regular journals rather than published as completely detached books.
Was there much of a change in the pace of activity in the field of magnetism in that postwar period?
How do you account for that? Because of the new experimental techniques that had become available?
Yes, new experimental techniques, realization of the importance and viability of the subject, and increased number of theoretical physicists. They all sort of combined:
What about people converting, switching over from other fields of theoretical physics into that, older people?
I don't think much of that happened. I think people tended to convert to nuclear physics. If anything it went the other way.
So it was mostly a new generation.
You said earlier in your other interview that there had been this tremendous gap in the application of quantum mechanics to these questions, to the solid state in general. And we know of certain developments in the theory of metals, work on semi-conductors in the 'thirties, but how large a group would you identify as being concerned with quantum mechanics in areas of magnetism and related issues, if you had to identify -
Before the war, you mean?
Yes, before the war.
Well, Gorter was interested and also Kurti to a certain extent, of course Neal had written some papers during that period. It was a very small squad.
The very fact that you can tick them off like that — then in the postwar period, the new people coming in, were they primarily the students of these pioneers? Or did they come from other sources?
I would guess, a little of both. I couldn't answer that question without studying things in some detail.
It might be good if one wanted to pursue this to take a look at the papers provided at the Amsterdam meeting, to look at the names, assuming it was not an elite conference but involved a lot of people in the field. Then you could get their origins and their relative ages and see in fact what got them into this particular activity. That meeting was not a theoretical meeting necessarily, it was experimental as well?
Yes, that's right.
At that period of the development of the field, did you feel that the experimental aspect was really moving more rapidly, let's say, compared to the theoretical?
You could answer that in two ways. You could say that the whole theory was handicapped by not having much experimental data, till the experimental data came along. So you could either say that it was more advanced in experiment than theory, or that experiment was just catching up to the basic theoretical concepts. The two went hand in hand.
These were international conferences. Were there national ones on the same subject?
We had a little national conference in this country at Baltimore. We called it a national conference, but we did invite some people from abroad, Roger Elliot for instance. I think that was in 1950 but I'm not sure of the date.
I'm trying to get a feeling for the overall growth of the field because this was a period when a number of fields with small conferences were beginning to —
— there were a number of conferences on magnetism in that general period.
I want to get on to something new, but it may be time to break.
I think it's time to break.
We're resuming now after a break of a few hours in which we had a chance to eat and look into some documents as well, and the point we left off — I talked about some international conferences, the overall development of the interest in magnetism, the effect of some of the postwar experimental developments. Before I return to that kind of question, I want to take up another career change for you. The Hollis Professorship came along, I guess it was 1951, and at the same time you became the Dean of Engineering and Applied Physics. What did this mean in terms of a change?
The Hollis Professorship was just a change in name. The actual income from the Hollis Professorship amounts to $100 or something like that and needless to say, it's supplemented from other sources. It is called the Hollis Professorship of Mathematics and Natural Philosophy, the oldest endowed scientific chair in North America — the only older endowed chair is the Hollis Professorship of Divinity. On the other hand, being more or less in a certain sense a pinch-hitter for the reorganization of the engineering applied science area, in the capacity of dean — that was a completely different thing. There was this sizable amount of income from the Gordon McKay endowment that created a number of vacancies to be filled. So I was in the rather unusual position of being a dean whose main problem was to spend the money, rather than to go out begging for it. When this ceased to be the case I resigned as dean. I felt I'd served my term.
You'd spent the money.
Oh, I hadn't spent all the money. Harvey Brooks had still some surplus in the accumulated income.
Was he your successor?
That's when he came in.
Yes. Previously he was a professor on our staff.
In that position as dean, was that somewhat different than the department chairmanship?
Yes, it was a very anomalous deanship, in that I was a dean, but I was under the dean of the faculty of arts and sciences. I sat at the table of deans at the faculty meetings with the faculty of arts and sciences, but still I was not a completely autonomous dean in the same sense as the dean of the law school.
What did the engineering and applied physics area consist of? Was it a question of loosely linked laboratories?
Well, there was the old Lawrence Scientific School which had great distinction, I should say going back to around the turn of the century. At one time there was even talk of a merger with MIT, but that fell through due to certain legal obstacles. There was a traditional engineering school here of purely graduate instruction at one time. It later on I believe....
We were talking about the various components of the engineering and applied physics domain, and you were talking about one old engineering laboratory, you mentioned Lawrence Scientific School, and I wasn't clear what you were saying about this older engineering laboratory.
Well, Lawrence Scientific School over a period of years became the Harvard Engineering School, which was strictly graduate. There was also created in the faculty of arts and sciences a department of Engineering Science and Applied Physics. It was usually referred to as the ESAP department, and it did not make too much sense to have these two separate organizations. There's no sharp dividing line between engineering and science. For a long time, they made some efforts to get a dean. Then they decided not to have a dean, and there was a faculty meeting of the people in the relevant areas at which Conant said that there were to be two appointment committees, one in one area, I guess metals, one in the electrical area, I can't remember. My name was mentioned on both of them, and after the end of the faculty meeting, why, Conant came to me and said, "By the way, Van, I want you to be chairman of both committees."
I was quite overwhelmed at that. Well, when I got into it so deeply, it seemed to the administration it was better to have a dean and they asked me if I would take the job, and after some soul-searching I finally did. So that's the story of how I became dean. It's like a person who goes into the water by inches. I didn't just dive in. I wasn't looking for the job in any sense.
On the surface it would appear somewhat unusual that a theoretical physicist then becomes the head of something with the word engineering and applied physics in it.
Yes, and, of course, there were certain groups among our alumni of traditional engineering types who were very suspicious of me for just that reason. I think I tried to be fair, giving recognition to the practical value of things, but on the other hand, I think that I more or less had the mandate to carry out the Bush report. There was an elaborate report put out by Vannevar Bush (perhaps you have that in the archives of the Institute) as to what should be done with the McKay endowment.
That's interesting. When did he do that report? He was really good at those things. He did the Science — The Endless Frontier report for the total government picture.
That must have been done between the end of World War II and 1951. The report was already a year or two old when I took over as dean, and it was more or less my Bible, my mandate or whatever you'd call it.
Do you have a copy in your file?
There must be one somewhere. All right, try to see that one is available.
What were the points of this mandate, that you recall? You say you did your best to carry them out.
Well, that there was a big future in what I might call the more scientific angles of engineering. And since the Gordon McKay Will specified that there should be emphasis on mechanical engineering, that presumably pointed more towards materials research than it did to purely electrical research. It instead it had been said, we should accentuate electrical engineering, I think the appointments would have had a somewhat different spectrum, although we had to have some coverage in both areas. I've sometimes pointed out to the alumni that computation machinery plays nowadays more or less the same role as shoe machinery did in Gordon McKay's day. That was what made Gordon McKay become the millionaire who made this big bequest to Harvard. He was sued for anti-trust violations; and so was IBM, so there's a certain similarity between the two — in different eras and different times entirely.
The people connected with Harvard had a role in the early development of IBM work in the computer.
Aiken of course had the first computing machine, built more or less like a telephone exchange. He had the benefit of the engineers from IBM, but somehow or other a rift developed between him and IBM. I think that's a well-known fact, not in any way confidential.
I know, I talked with him briefly on the telephone. What areas did it mean you'd hire in? When you're talking about materials research, does that mean you'd bring solid-state physicists?
Well, that would be one angle. Bruce Chalmers was more nearly in the traditional metallurgical area. We brought in Carrier in the general area of applied mathematics and elasticity. We brought in Budiansky during my time. In the electrical area we brought in Hogan who later became a vice president of Motorola, then president of Fairchild Camera, a position which he holds now. We had Walter Brattain as visiting lecturer for a term.
While he was still at Bell Lab?
Yes. I think this gives you an idea, the general -
Right. What about the development of facilities? I look at the area now and I see a vast number of laboratories and all up there. Did any of these developments start during your — ?
Well, the Gordon McKay Laboratory I inherited as more or less an empty shell. I was quite a while getting the thing functioning. I was responsible for building the bridge between Pierce Hall and Cruft Laboratory so you could walk under one roof from the physics laboratory to the area of the Division of Engineering Science and Applied Physics, and I think we've always prided ourselves on close relations of the two. I have a hard time remembering which of my Ph.D. students were students in the division, which were in the department of physics, or chemical physics (that's a field of graduate specialization), or even in chemistry. I've had men of all four types take their degrees under me.
Now, the work for example of Ted Hunt, did that come under your general —
That is an area I inherited. Ted Hunt was a person who supervised the acoustics area, which was pretty much his own private field of endeavor. There was also soil mechanics, which had distinguished people, the Casagrande brothers, a little handicapped because of the fact we didn't have a big department of civil engineering. The fact of the matter is that we just couldn't, even with the McKay endowment, afford to compete with MIT in all the fields and ramifications of engineering that it covers, and we tried to have enough of our own that would be distinguished and differentiable.
Well, what kinds of students did you find coming into the program? What backgrounds did they have?
Very varied backgrounds. The ones that went into solid state physics I think usually had far more mathematical training than the fellows that wanted to go into a subject like soil mechanics.
I'd think they would.
—it's a heterogenous area, there's no doubt about it, partly the result of inheritance of fields in which Harvard had shown strength in the past.
At the same time during this period, the fifties, other universities were developing solid-state programs, some broadly focused, some more narrowly focused; for example, Slater's group at MIT was more narrowly focused technically. How would you rate the development of solid state at Harvard during this period, compared to what was going on elsewhere? First of all, was there a well-defined group which one could call a solid-state group?
Well, we had Bloombergen, I forgot to mention him, among my appointments. I remember Ramsey saying he couldn't think of anything that would get solid state physics off the ground more than to appoint Bloombergen to a position of tenure. That we did and he was very successful in attracting graduate students. And out of that nucleus have grown some of our more permanent appointments, men like Peter Persham, for instance.
How large was the group in the period from the mid-'fifties, for example?
I couldn't tell. Depends what you mean by group, size of faculty, tenured faculty?
That's one way, another is the number of Ph.D.s specifically in solid state during that period.
I couldn't say without looking the thing up. I'd be afraid that I might be incorrect in my records. I should say that my latter years, the number of Ph.D.s in solid-state physics would be on the order of magnitude of 10 to the nearest decimal. Certainly more than 1, not as many as hundreds.
Over the period?
I said during the latter years. This is the annual crop.
Was it generally felt then that Harvard had a significant solid state effort, or were the other institutions in the country much better known for emphasis on solid state?
I would say that we were pretty much in the advance guard. I think we'd stack up Harvard pretty well, when we got Bloombergen here and Vic Jones. Of course I had some students of my own in that general area, if you include the magnetism of solids.
I meant that as part of it. What I'm getting at, I have the impression that Harvard throughout this period was diversified, and based on what you told me of your chairmanship, you weren't specializing in a particular area. You were talking about individuals.
So it wasn't the same as Berkeley, let's say, which would be overwhelmed with a single large laboratory.
Yes, I hope we've avoided that.
Let me ask you to think over that six-year period when your job was to spend money, to pull these pieces together. Were there any problems that developed during the period which were specially difficult?
Well, I think the fact that we had two separate administrative branches that we had to merge was bound to create problems, and there was also, I should say, a clash between the mandate of the Bush Report and what some of the older alumni thought should be the aspects of engineering that Harvard should emphasize. We were certainly subject to criticism in some quarters, especially at the beginning of my term, a little less perhaps at the end.
How did you meet the criticism? Did you just proceed with your plan, or were there very serious changes in direction as a result of the pressure?
I don't think there was too much of a change in direction as a result of these pressures. We did lose our accreditation in engineering for a period, but got it reinstated in most of the areas. That created some problems for a time.
What was the basis for that?
That we didn't have more laboratory facilities in mechanical engineering; that we didn't have enough courses in design; I should say, we were too theoretical.
Wouldn't that reflect in students self-selecting themselves? If they wanted more of the non-theoretical, wouldn't they go to a place where they would get it?
The implication is that you got more of the theoretically inclined students.
Yes. And there seemed to be very few of our students that cared whether they were accredited engineers or not. There was not much pressure for that, except in sanitary engineering where it was necessary, and where there's never been any question. I don't think we ever lost our accreditation in that area. We had a sanitary engineering department which was closely related to our school of public health. So you can see it was rather a far-flung division in its interests. How to distribute things between the different areas, budgetarily and otherwise, was bound to create problems. I just tried to do the best I could for a while. Harvey Brooks has now been dean for 15 years. I was for six.
I should talk with him about his feelings on what he's been able to do. When you say, more theoretically oriented in their engineering training, you mean that this would reflect in the coursework as well?
You'd have a larger dose of physics, for example, than they'd get otherwise.
Yes. And I would say, in a certain sense, in retrospect you can say that Harvard was a little bit in the vanguard. Over the years a great many engineering schools have put less emphasis on immediate bread and butter courses, and more emphasis on courses on broad fundamentals without specific application. Of course, the trump card of the physicist is the fact that when radar came along in the war, it was by and large the physicists that manned the Radiation Lab at MIT, probably more than the traditional electrical engineers, certainly the power engineers.
A good deal of their work was engineering work.
Yes, surely, but they were problems that were new to everybody, and a physicist perhaps has a somewhat broader training than a specialized engineer. It's bound to be the case. Probably should be. Without reflecting in any way on engineers, who are very well competent to work with specific problems.
The wartime experience raises another question, and that the effect of the wartime involvement in military research on campus, for example, the Harvard Underwater Sound Laboratory, which was Ted Hunt's area, the Radio Research Laboratory — what was the effect in the postwar period, in these years we're talking about, of military research on campus.
I can't feel that there was very much effect. There was a concentration of very able young men. (Fred Terman took an awful lot of them to Stanford, when he went back.) But I don't think that the wartime research made us in any sense a university of classified research. In fact, I don't know if we had any, as soon as the war was over.
But there were government contracts, though, for basic.
Yes, for basic research, not for classified.
This is a whole different story, one we can get specific on — for example, ONR support of certain projects, before AEC, and before NSF came in.
Yes. Well, for instance the old Radio Research Lab during the war, which included part of the biology building, was a heavily guarded area. When we moved into the Gordon McKay Laboratory, I don't think any of it was secret.
There were no problems raised during that period?
I don't think that there were great pressures on Harvard to do classified research. Mr. Conant, I think, was very much against it.
All right, we've covered the period in terms of your deanship.
I think for my performance as dean you'd do much better to consult members of my faculty or the students in that area than you would me.
I think you were saying when we interrupted that the best evaluation of your years as dean would be from students and faculty...
— who benefited or not from your domain. I noticed when I was making the telephone call, they did give you something when you left in September '57.
Oh, I can show you that. [Shows a gold-plated combination thermometer-hydrometer-barometer.]
It's very attractive.
I had some nice letters, too, from the members of our visiting committee, some of whom were originally very suspicious of me.
Well, in six years you can turn them around a bit. But during this same period, you were involved in professional activities.
I tried to be. I was President of the Physics Society, that's certainly professional.
I wanted to ask about that. I know how the presidencies go. It's a mark of honor for an individual to become president. You first are president-elect and so forth during this succession to the presidency, and the actual presidency is one year. During the period in which you were active, and the brief period preceding and following it, were there any particular issues that came up that were particularly important and worth talking about?
No, I don't think so. It's like being college president in the old days. Life was relatively calm. There weren't the sociological issues that there are now. I can't remember any particular issues that came up during my administration. The one thing that did come up was that it suddenly developed that the Physical Society was in bad financial straits. That was rather suddenly presented to us by Dean Pegram, who was treasurer, at one of our meetings, so that I'm afraid that my administration was also the time when there was a rather large percentage change in the dues for members and fellows and subscription to the Physical Review. That of course was something over which I had no control.
This was during the period when Karl Darrow was still executive secretary?
Yes, that's correct.
And was therefore handling the day-to-day affairs, arrangements.
Oh yes, sure.
All during this period you maintained relationship with the various editors of the journals — we've looked into your files — especially Tate — when did Tate? Wasn't it 1950?
And then Hill took over, then Goudsmit moved to Brookhaven somewhat after hat, right?
Well, in the later years in which you would have been on the council there were a couple of controversial national issues. One was the Astin case, which we found records of in your files. The other later was the Oppenheimer hearing, both of which affected the Physical Society officially and unofficially. There were official statements, I believe, made in both cases. I'm not sure about the Astin case. I know AIP was asked, as you saw from the letter to appoint a representative to a committee. Did it impinge on the Physical Society? I guess Fermi was president when that happened.
See, the president continued only for a year or two as member of the council after his term expired, except for the very early presidents who were life members, so I didn't have very much to do with the Physical Society administration after I ceased to be president. So I never was really involved in the Astin affair except in my capacity of being on the visiting committee of the Bureau of Standards. And the Oppenheimer affair I never was involved in. Nobody ever interviewed me about Oppenheimer, in any respect, as a matter of fact, from any official source. I've known him ever since 1926, which is I think longer than most people knew him.
You knew him from his Harvard days?
I didn't know him at Harvard. I met him first in Cambridge [England].
On the Oppenheimer thing, even though there may have been no official involvement, it became an issue within the physics community. Do you recall any discussions about whether the community should take a position or should not?
I don't recall any particular communications on that subject. There wasn't very much you could do. I mean, there was a court of inquiry, and when the court decides one way, why, that's it.
How did that differ, of course it did, discussions and everything, from the Astin case in which again it's an involvement of government and science, the Astin case where there was -
That was more an issue of administrative wisdom, and the Oppenheimer case of course was a case of reliability. Actually I think Oppenheimer was an honest man and I don't think that should have been made an issue, but of course it's perfectly true that he did have leftish friends and that's what caused all the trouble.
The FAS and other groups like that in the postwar period took an interest and a stand on many of these issues, including atomic energy legalization, looking into the relationships of science and government. Did you in the postwar period get involved in any of those groups?
I took a mild interest in the FAS right after the war, when we thought it was our duty to educate the public to the fact that there is no such thing as a real defense against the atomic bomb, and how devastating it was, and that you couldn't keep it secret forever. Those are certainly all three truisms. Everybody knows it today but it was not so well known in 1945-46.
You say you took an interest. They had educational programs -sent out speakers and so on?
I don't think I was ever elected to be a speaker, but I guess I would have been willing to.
Now, on the Astin thing, what was your responsibility as a member of the visiting committee of the Bureau of Standards? Was this a scientific committee to judge — ?
it was an advisory committee, I suppose, for the policies of the Bureau of Standards. I couldn't tell you the exact terms of the thing, but I think it's a Congressional mandate that there be such a committee.
It was mostly on scientific —
— usually, but this thing broke when we were right in it. Norman Ramsey said it looked like a completely peaceful appointment. Instead it turned out to be a very stormy period.
Did you have any inkling of the whole issue occurring, or was it public news for you as it was for so many others?
It was public news to me just as to everybody else.
So the visiting committee was not involved in any way in any of the preliminary discussions, it was only reacting after?
Yes, reacting after the fact, and [Secretary of Interior] Weeks, as you know, was finally talked into reinstating Astin.
What part do you think the committee played in that, visiting committee?
I think we did our bit. I think Merwyn Kelly was very influential in convincing Weeks.
What part do you think scientific evidence and statements from scientists played - in two senses, one, in terms of the general reaction of the scientific community regarding the interference, as they put it, of politics in science, and second, about the scientific merits of the issue — two separate things, one is a principle thing, one very technical —
Well, certainly the scientists were all, by and large, behind Astin in the matter. The second thing, as to the effectiveness of this battery additive, I am not an expert. It would be my guess that most of the evidence was negative but that has been challenged. It was a little controversial at this time. Although most people were suspicious there were some people who felt maybe there was something in it.
You mentioned that Kelly had a role, but it was the visiting committee he was speaking for, wasn't he?
I would say it was pretty much of a kitchen cabinet type of thing.
But the committee supported him.
Also that's a whole story we can document as well, I think. Now let me get back to a little bit of science. Were there any other advisory functions that you had during the period of the 'fifties, either government, industrial or academic?
Oh, I was chairman of the Physics Section of the National Academy of Sciences for two or three years. That involved some administrative work of a much more routine nature than my administrative work as dean.
That involved committees but never a real office at the Academy?
Oh no, no, no. Just polling the section for their votes and reporting it to the secretary and so on.
How did that differ from the IUPAP vice presidency that you had somewhere along in there, I forget exactly when?
I think the president of IUPAP is the one who really presides at all these things, and vice president appointments are more or less honorary. There's more work as chairman of the magnetism committee of the IUPAP than there was ever for me as vice-president as such. I can say that with a good conscience, because being chairman involved your calling together a committee and polling them and so on, whereas the others were mainly glorified council members.
During this period, then, these outside activities don't seem to have interfered too much or taken too much of your time from your deanship and from your teaching and research.
That's true. You couldn't have made those the major emphasis. It wouldn't have been right.
Toward the end of this period, toward the end of the 'fifties, we're talking about now, you mentioned the pleasure you had, and somewhat the surprise, when you went to the Dublin conference in 1958, which essentially focused on ligand field theory?
Let's talk about the conference. It was a chemistry conference. How was it that you were invited in the first place? Was it because of the subject matter?
Certainly. The point is that the chemists annexed ligand field theory. I was really startled that they talked about quantities like dq such as Schlapp and Penney had in their papers. They'd read those papers and were getting interested in things that were pretty much physics in the early days. Nobody was too much interested before the war. I still have reprints of some of my earliest articles. Recently I wrote a paper, I should say a rather minor paper, connected with dielectric constants of dilute solutions, and I've had more requests for that one paper than I think I've had for any of my papers, though it is certainly not my most important paper by any means.
Who are these people who asked for reprints?
You mean now?
They seem to be chemists from all over the world.
That's a very practical thing for them.
Yes. Well, they read the literature. Kramers once said that chemists differed from physicists: they knew the literature. Whether it's true or not, I don't know, but it's certainly a succinct statement that he made.
Well, have you kept up with this interest, before 1958? Were you aware that it was taking hold?
I hadn't realized the extent to which it was taking hold. That was pleasing and startling to me.
When they did discuss it there, did you find they had taken the subject a good deal further than you had?
I wouldn't say that. I think they had applied it to more materials, perhaps. The basic theory was essentially done in the original papers of Schlapp and Penney and myself in the early days. Then of course there was a much refined theory developed by the Oxford people after the war, and by the Japanese.
Who in Japan? It would be good to know this, I don't know who was involved.
Kotani's group was one group I think that did a good deal with it.
From the physics point of view?
You kept up with that work, though.
Yes, I'd kept up with that work at that time, I think, yes.
It must be a very rewarding thing to see the maturing and application of a seed that you planted in this case almost 25 years earlier.
Well, what I'd like to do, we could go through in detail a whole number of papers, but think that in the time that we have left it might be good to talk about certain personal characteristics of your own style and your own interests. I was, in the line of questions, trying to develop the relationship between administrative and teaching duties and research duties and so forth, but we rarely touched on personal life — the fact that you were not living alone in this world. You've lived in this house since 1937, I think?
What about the so-called non-scientific interests?
The fact that I'm a rail buff has been played up altogether too much. It's in introductions to me at various conferences and so on.
When did that interest start?
Le talk about it a little bit, might as well since it's talked about -
That's when my grandfather let me read an Italian timetable at the age of 7 when I was recovering from diphtheria in Bologna.
That infected you?
Couldn't read the Italian very well.
But what was the impact of reading it?
Got me interested. I'd always been interested in trains and that sort of added fuel to the fire.
Then you pursued it as a hobby after that?
More or less. Not locomotive types and things too much, more the scheduling of trains I should say was my interest. Then I'd say playing bridge, socially, over the years. When I traveled with my parents and an aunt before I was married in 1926, we had some little cardboard boards on which we could play duplicate, rather unusual for those days perhaps. My wife and I play bridge occasionally. I have my father's collection of Japanese prints. I like to travel. In my younger days I loved to ride a horse in the Rocky Mountains. I think you can see that from my reprint, "Travels with Dirac in the Rockies," which is a chapter in the volume "Some Aspects of Quantum Theory."
And music seems to have been a continuing interest.
Yes. I used to play the flute. I played the flute in the Wisconsin Band and also for one year in the orchestra. That's as far as I ever got. I could never have been a really good musician, that's for sure. I lacked the coordination and so on that would make a good musician. But I like music of the classical type. I shocked Ehrenfest when he visited Minneapolis in 1924, when I told him I liked popular music. He thought that was completely irreconcilable with my having written any respectable papers.
When you say popular music, what do you have in mind?
I guess it was probably called jazz in those days — the things you hear at Old Timer's Night at the Pops, things like "Margie" and so on.
Or even the Paul Whiteman things of that era?
I don't know what they are.
Well, kind of large band where he had some jazz instrumentalists.
I never went in for that.
What you're talking about is more the popular, including some show tunes and -
And now your musical tastes, do they still go the same way?
I think pretty much the same way. When the Boston Symphony has a program that doesn't have much modern music, I try to buy a ticket.
But you resist the modern music. Modern starts with Stravinsky?
I guess so.
There are lots of people who would say Stravinsky's very old now in terms of musical —
— I'd say Monet and Manet are very fine modern artists. And as to Japanese prints, Kiyochika and Goya. Rimsky-Korsakov wrote some nice modern music too.
I guess he'd still qualify as modern. Now that you're "retired" (in quotes) do you find more time to get involved?
Yes. I think I just take a little bit more time. I drive myself less hard and the result is I never get the second edition of my book done. I'm finishing up a long pair of papers I'm writing with Foglio, an Argentinean post-doc who came with me to Harvard a few years and is now out at Southern Illinois University in Carbondale. I hope we'll get that done. It seems to me I'm always being asked to write a paper for an honorary anniversary volume in honor of somebody or other. Those come up about twice a year lately. That takes some time.
You have this wonderful tendency to try to get recognition for others who, you feel, have done good work, whose work should be known — for example, pointing out to historians and others about Valasek. And then the desire to publish something that's particularly well written and interesting from the human interest point, not something that you wrote necessarily but something that someone else wrote, desiring to bring this before other people. Do you feel that this kind of recognition, this kind of appreciation of human expression is neglected?
Oh, I think it's as satisfying as writing some paper on some minute aspect of something or other. I was very pleased when American Journal Of Physics published the Bleakney and Kastler memoirs, for instance.
I know you were. That's why I'm asking about the nature of the satisfaction. You compare it to doing a paper on a very small subject. Would you characterize some of the scientific papers that you've done as taking some theory which you perhaps developed and then applying that theory to a very small area -
yes, I mean I wrote a paper on magnetism, a 1932 paper, my favorite, which showed very broadly how the different salts of the iron group had behaved very differently with regard to their magnetic properties. Now you bat your head against a stonewall trying to explain all the properties, say, of europium iron garnet, magnetic resonance, anisotropy, hyperfine structure, quadrupole effects in hyperfine structure, getting all of it together, also line breadths and gyromagnetic ferromagnetic resonance, with the same material. You have the same essentially ligand field and exchange formalism that is involved. To get a theory that will fit all the facts is a difficult assignment. But it's a different type of thing entirely from my 1932 effort when nobody understood much of anything. Now I'm trying to explain a lot of experimental data.
When you look back on the various pieces of scientific work you've done, the various problems you've addressed, what do you find is the most satisfying? You talk of a favorite paper, but I mean beyond that output, what period, what class of problems?
Well, the period is easy enough — it's when quantum mechanics broke. Then it was an orgy of breakthroughs and various pieces of application of quantum mechanics. I think it's natural that most people, probably, that were competent theoretical physicists at that time wrote their most important papers in that era, because there were major things to clarify. It's a little like staking out pieces of land in a new continent, as compared to building some specialized building when the whole territory gets highly developed.
This was new territory, was exciting, you felt you were in virgin land.
Yes. It never had the emotional impact on me that Oppenheimer described in his speech to the AIP, when he said it was a period of fear and terror, or something like that, I haven't got the exact words. I was just too busy "keeping up with the Joneses," trying to understand what the European physicists were doing, to have any thoughts on what great things were going on.
I know it was an enormously productive period for you. You identified one problem after another.
It kept me so busy that I didn't have much time to be philosophical or romantic or emotional about it.
It's not clear whether Oppenheimer was at the time either. This is in retrospect.
Oh. Well, that's what he says anyway.
Well, there was a time, I hear, I'd like to get your impression of it, when a lot of young bright theoretical physicists were awfully inhibited because they realized that so much was happening, and if you didn't write that paper someone else would, and they saw so many giants on the scene doing so many —
— I never heard of this inhibition.
Well, there are a few people who've said they felt like quitting physics at one point when they realized how fast things were moving. They had a little bit of self-doubt until they could demonstrate that in fact they could produce, too. There were a few.
I suppose there are.
Maybe this is what Oppenheimer was referring to. I'm not sure, I'd have to read that again. You say you were too busy to think about that.
I had some good students and didn't have to worry too much about marginal Ph.D.s who can take a lot of time.
So looking back over the whole period, you would still identify those as the most exciting and satisfying years?
I would think so.
This would extend into the early thirties?
Well, I think maybe that's a good note to end this on, and then have you look at the transcript. There may be other things that occur to you, or occur to me, and we can do it. Also there are things we mentioned in the course of this that we'd like to look up, the Bush Report and a few other things. The transcript will serve as a reminder. Fine. Thank you very much.
See Phys. Rev. 71, 425 (1947).
Actually she was a student at Radcliffe. Harvard and Radcliffe in those days were not coeducational in any respect except in fact.
Then president of BTL.
The date Fermi's first reactor went critical - ed.
Proc. Phys. Soc. (London) 35, 296 (1923).
Now at Universidade Estadual de Campinas, Unicamp, Brazil. See interview correspondence file.