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Interview of Joseph Valasek by Roger H. Stuewer on 1969 May 8, Niels Bohr Library & Archives, American Institute of Physics, College Park, MD USA, www.aip.org/history-programs/niels-bohr-library/oral-histories/2345
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Family background, early schooling; undergraduate studies at Case Institute of Technology (B.S. 1917); assistant physicist at National Bureau of Standards (1917-19); research on piezoelectricity of sodium chlorate and bromate; World War I work in pyrometry and optical glass manufacture; graduate studies at University of Minnesota (MA. 1920, teaching assistant 1919-20, Ph.D. 1921, instructor of physics, 1920-21), member of physics faculty; research on ferroelectricity of Rochelle Salt Crystals and location of Curie Points; X-ray spectroscopy research at University of Upsala, Sweden 1928-29; comments on nuclear physics at University of Minnesota.
I was wondering if you were going to ask me the questions, and then I’ll reply to them?
I notice you have a series of questions, and some of them I ignore, and some I elaborate on.
Yes. What I did was to go through your written responses and simply fill in marginal notes, like this, just to see whether we can talk about some of the questions that I asked. I think anything we say now is really ancillary to this, because this is really a marvelous piece of work that you did in response to my earlier questions. [Brief break in recording] Your father, in this country then, was a journalist after leaving Czechoslovakia?
Well, in fact, he found journalism wasn’t good for him. In his later years he was just an office clerk, assistant to a manager in a brewery.
And your mother was the daughter of a physics teacher in this country?
No, in Czechoslovakia.
And did your mother do any work in physics in this country?
No, she came just to be with her sister, who had emigrated to this country, to see the country. She met my father and they got married and stayed here. My grandfather’s (the physics teacher) full name was Josef Pylik.
When you went into high school in this country in Cleveland, I notice that you completed high school in three years. Was that a special three-year program of some sort?
No, I attended summer school three summers and picked up enough credits or almost enough — I took an extra course after school, as a matter of fact, to get my diploma after three years. I picked up most of the credits by attending summer school every summer.
Was that at all usual? Did anyone else do that?
No, I don’t think it was usual.
You almost had to make that decision upon your entry into high school, didn’t you?
You just decided that every summer you would go and complete it in three year.
That’s really rather remarkable. Not many people do that today.
Well, I’d been taking shop work while I was in grade school. They had special classes in the summer for students, making various things in the shop — manual training — so I was used to going to summer school anyway, and in high school I kept on. In college I worked in the summers. So I didn’t take any long vacations.
I think that’s fairly evident from the remarkable way in which you went through. When you were at Case, you say here that “D. C. Miller announced that he would like to have a few of us major in physics.” Was there a grad school at Case at that time?
No, not at that time.
Do you recall when the graduate school was established there?
I see. So it was a four-year program at Case, and after that graduates of Case would go — where? — to Harvard at that time?
There weren’t very many going into graduate work. The only one I heard a lot of was E. C. Kemble, and that was in 1911. You see, I graduated in ‘17, six years later.
And at that time Kemble was already at Harvard — is that correct?
This work of Miller on the ether drift is quite interesting, although I know very little about it. Can you recall some of the details on this?
Well, he insisted — I think mistakenly — that there was a positive ether drift that never was really negative. Even Michelson and Morley had observed a small effect. And Miller said that there was a small positive effect indicating a motion of the solar system toward some group of stars. He presented a paper on that at an A.A.A.S. meeting and got a thousand-dollar prize for his work. He had a curve showing a positive shift of the fringes, smaller than was expected.
It was smaller than the 2nd order effect?
Smaller than that, but he insisted that it was real and that it indicated a motion of the solar system.
Do you recall what year that was?
It may have been 1930 something — I imagine the early ‘30s. I have a reprint of the paper, and I think it’s in the office in my files at the University. He sent me a reprint.
That would be extremely interesting to see. [Brief interruption] This is an obituary notice in Science, Vol. 93, 270-2, (1941).
It’s 1941. It was written by H. W. Mountcastle.
I see. Here his papers are listed. Oh, these are the books.
Yes. He suggested an experiment on the determination of the absolute motion of the earth, 1933. I think that’s the one. Let’s see if it mentions anything. No, I don’t think it does.
It was roughly at that period of time or shortly before that.
You say he won a prize for this work, so apparently there were quite a number of people who believed that his effect was real.
Here it says: “Later, as is well known, Dr. Miller alone repeated the experiment many times, his efforts culminating with his painstaking observation on top of Mt. Wilson in l925 – ‘26. Individual interferometer readings made by him number over 200,000. Continually he insisted that recognition should be given to the small positive result which he and both Michelson and Morley had observed.” This result he believed was a sufficient refutation of the Einstein relativity theory. His chief contributions were in acoustics. He invented a phonodeik and analyzed wave forms of sound from voice and music. He was a flutist. He had quite a collection; he had some 1,400 flutes dating from earliest times to the present. This fine collection along with books, pamphlets, music, book scores, pictures, autographs and so on was given to the U. S. government, where it is fittingly exhibited in the Library of Congress in Washington. He composed 30 pieces of music for the flute and other instruments.
So at least by this time it looked as if there wasn’t anything definite to his results. He himself kept insisting that there was something to it, but…
That there was a positive ether drift, although smaller than the exposed effect.
I notice that, talking about the textbooks that you used at Case…
I left out two. I was going to add Emtage’s Electricity and Magnetism, and of course Miller’s Laboratory Physics I omitted, too. I thought I’d add that.
I was wondering: Was Thomson’s Conduction of Electricity Through Gases or Rutherford’s book on radioactivity at all used as textbooks over here?
No, not at Case, They were used in Minnesota as secondary reference books. In fact, Erikson taught a course in radioactivity in which he used Rutherford’s book.
I see. And Richardson’s Emission of Electrons from Hot Bodies, think it is — that wasn’t used at…?
Just as a reference, not as a textbook or a regular text.
And to pay your way through college you say you borrowed $300 from the Severa Fund. What is the origin of that? I’ve never heard of the Severa Fund.
Well, maybe that doesn’t exist anymore. But he was a manufacturer of patent medicines in Cedar Rapids, Iowa — a Czech — and he established a fund to help students of Czech descent. The loans were of very low interest, and you were asked to pay it back within five years of your graduation if you could do it, if you could afford it, and take any course within Czech studies that was offered at the University you attended. And since there weren’t any such courses at Case…
That obligation fell by the wayside. Did Coblentz go immediately to the National Bureau of Standards?
I don’t know whether he went on to graduate school or not. I think he did somewhere. I could look up Coblentz. It’s rather incomplete. For example, Tate isn’t included at all and neither is John Williams, and we have buildings named after them out here at Minnesota. Coblentz. (reading) “Physicist, Ohio, Case, B.S. 1900.” And probably honorary: “ScD, in 1930 from Case, A.M. Cornell, 1901; Ph.D. 1930.” [Reference: World Who’s Who in Science, Marquis, 1968.]
Ph.D. very late. That date seems erroneous almost, doesn’t it?
Yes, it does.
I wonder if that shouldn’t be ‘03 instead of ‘30. It seems as if it should be.
Let’s see: “honorary fellow at Cornell 1903 - ‘05, physicist Bureau of Standards “04 - ‘45.” You see, he went to Cornell from Case, graduate work.
And then from Cornell right to the National Bureau of Standards.
Maybe he didn’t get his Ph.D. immediately. Maybe it was granted after he’d done a lot of research. He got his master’s at Cornell, but he was at Cornell apparently… Yes, honorary fellow ‘03 - ’05. Here it says to ‘04. That’s odd, Bureau of Standards ‘04 – ‘45.
I imagine by the time you arrived at the National Bureau of Standards Coblentz had quite a crew working for him already.
Oh, yes. He was one of the prominent physicists there at the time I was at the Bureau of Standards.
And I guess he’s best known for his work on infrared spectroscopy.
Let’s see about Miller. Dayton Clarence Miller, A.M, 1889; D. Sc. Princeton 1890. Later he received several honorary degrees: L.L.D. and all this kind of thing. Yes, here it says: “A.A.A.S. prize 1925.” That was on the ether drift.
I see. And so the article [Review of Modern Physics, 5 (1933) 202-242] of ‘33 then is sort of a summary probably of that work and work that he carried out in the meantime.
Yes. I heard him give that talk in 1925, and he projected some pretty interference fringes. He gave a very good talk.
Was it well attended?
Yes, it was very well attended.
How large were meetings in those days?
Not so very large.
Now they’re so large.
Yes. I did some work on piezo electricity of Sodium Chlorate and Bromate. I grew the crystals and presented a paper on that at one of the meetings. I never published it as a regular paper — so I don’t have any reprints. I don’t know where one could find the abstract of the paper.
This was at an American Physical Society meeting?
American Physical Society meeting in Kansas City probably 1925 or so. I had made some calculations on the expected effect from the elastic deformation of the crystal and the known crystal structure and the tilting of the dipoles. I didn’t find a very good agreement, just the general order of magnitude, but not very good agreement with the experiment. I never followed that up any further.
Is that what you refer to later on when you say that you ...?
I mentioned that I had tried out Thomson’s theory, Kelvin’s theory on this piezo electricity and Sodium Bromate and found no…
Found just order of magnitude agreement and nothing in detail.
Nothing very good.
Well, I wonder if an abstract of that might not be in, for instance, Physical Review.
Probably, although I tried to look up some of those early abstracts, and I couldn’t find them. I wonder if they were published in a separate bulletin, which I don’t have any more. For instance, that first paper that announced this dielectric hysteresis in Rochelle Salt Crystals –- that was in the spring of 1920 that that paper was presented. I think Swann presented it for me. I gave you a typewritten sheet of the abstract of that paper. But I couldn’t find it published anywhere. I looked in the Physical Review around that time and couldn’t find the abstracts.
I see. That seems rather unusual, because most of the papers are always abstracted — [See Physical Review, 15 (1920) 537-538.]
Are the abstracts published in the Physical Review now?
To my knowledge at that period of time they were surely published in the Physical Review. There was not a separate journal. Now, of course, there was Science Abstracts. But they abstracted papers as they appeared in journals. Didn’t they have a staff of abstractors?
And so that really wouldn’t be the same thing.
Science Abstracts were abstracts of papers in different journals.
Of all languages, too.
Of all languages, yes. That was put out by the British Electrical Engineers, I think.
I think that’s right, yes ... extremely useful. You mentioned the exodus from the campuses in 1917, April 1917. I remember reading in one of Rutherford’s papers that he says that work in physics was disrupted very much in England during the World War, but some good work was carried on in America during that time. I was wondering whether this was lack of knowledge of what really had happened in America, or whether the war had very seriously affected work in physics in this country, too.
Well, it had to a certain extent except military connected research. That was carried on. The Bureau of Standards was very active. When I graduated (or before I graduated), I got three offers of positions (I didn’t mention that in here [the prepared autobiography] either): one at the Bell Telephone Company and one at Goodyear Rubber Company in balloon research.
In connection with the military.
Yes, They were making balloons — blimps and things like that, you know. And then the Bureau of Standards, and I took the Bureau of Standards position.
In terms of the experience that you gained at the Bureau of Standards, that was probably the —
Yes, that was a good choice.
You mentioned that later on in the Bureau of Standards the war had cut off the supplies of optical glass from Germany. Prior to the war was virtually all of the optical glass in this country supplied by Zeiss, for instance?
Yes, Schott-Genossen in Jena. Most of it came from Germany. There was a little work, small production, in Pittsburgh as the Pittsburgh Plate Glass Company branched out and tried to make optical glass. But they weren’t very successful. There were a lot of problems in the manufacture of good optical glass. That was taken up by the Bureau of Standards and different groups took up different parts of the problem. In the pyrometry section we worked on the annealing.
Was there more or less of an overt attempt to duplicate German techniques or …?
Oh, to see if one could find something better, because the techniques were traditional and hadn’t been investigated scientifically, and so it was thought that research in that field might turn up better procedures and better products.
I know very little actually about the influence of Abbe and Schott and the Zeiss works in Jena, but understand it was really a complete transformation of their techniques. Is that correct? Isn’t it true that Abbe’s innovation, really, if you can call it that, was to attempt to calculate the proper characteristics of lenses and then design from calculations rather than the former technique, which was more or less of an empirical lens-grinding technique until aberrations were minimized. Is that an accurate statement as far as you know?
I don’t know very much about Dr. Paul Foote. He became editor of the Physical Review also, didn’t he?
I think so. He was head of this pyrometry section at N.B.S. for quite a few years, and then he went to Gulf Oil Company in Pittsburgh and was director of their research laboratories. I think he became vice-president of the Gulf Oil Company. “Paul Darwin Foote, A.B., Western Reserve, 1919; D. Sc, 1961,” that’s honorary. “A.M., University of Nebraska, 11; Ph.D. Minnesota, 1917. Let’s see: “Began as assistant physicist U. S. Bureau of Standards 1911; senior physicist ‘24 to ‘27; executive vice-president Gulf Research and Development Company, Pittsburgh; vice-president Gulf Oil Corporation and Gulf Refining Company; retired 1954. Assistant Secretary of Defense, Research and Engineering, Department of Defense 1957-58; chairman National Academy of Sciences. Panels adviser Bureau of Standards, ‘60-’65; Recipient Achievement Medal, University of Minnesota, 1951.” He was working with Fred Loomis Mohler, F. L. Mohler, on the resonance and ionization potentials and wrote this book, The Origin of Spectra, in 1922, and with others, Physics and Industry; editor-in-chief of the Journal of the Optical Society of America, Review of Scientific Instruments from ‘21 to ‘32; associate editor Journal of Franklin Institute.
So it was not the Phys. Rev. I was thinking of. It was the Journal of the American Optical Society.
There are a lot of questions that I guess one could ask or one would like to ask about John Tate. He became managing editor of the Physical Review, and he really established the Reviews of Modern Physics, too, didn’t he?
I believe he did.
Can you tell us something about that at this period of time? What was the process of refereeing the articles during that period of time? I know it was mentioned to me that when an editor was at a certain university that often he gave the articles simply to his colleagues down the hall to referee. Or did he send them out?
No, he handed them out to his colleagues.
Could you elaborate on his career? I know you talk about his career back here towards the end, but any information at all that we could…
I don’t have any. You see, he’s not included in this.
In the Who’s Who in Science.
So I can’t look up the dates as to when he was editor and how long and when he died. He died rather young [1950, age 61]. I don’t know the dates. I can look them up elsewhere.
The dates perhaps one could come across in some other way.
He’s probably in American Men of Science.
Possibly. Did he really establish his career here at Minnesota? I mean his career became established…
Yes. He came to Minnesota after he got his Ph.D. in Berlin and then took a leave of absence during the war to work on this airplane field lighting. I mentioned that. And then he came back to Minnesota and stayed here the rest of his life.
Do you recall where he was born? Was he born in this part of the country?
No, he was born in Lenox, Iowa in 1889. He did his undergraduate work at the University of Nebraska. There was sort of a Nebraska dynasty here for a while. Foote came from Nebraska; so did Tate and Buchta. They were all Nebraska people. I was associated with two of them at the Bureau of Standards and came under their influence.
So it was really a reciprocal arrangement when you were at the Bureau of Standards. When you talked here about “Foote directed me to study the possibility of using the recalescense temperature” — that’s an unfamiliar term to me.
I think that’s the same thing as the Curie Point. I haven’t been able to check that specifically. But recalescense means that, as you cool the iron, it reaches a point at which it suddenly heats up, and even in a dark room you can see it glow again. There’s an evolution of heat, I think that’s the Curie Point.
A phenomenon that does occur at the Curie Point also.
There’s a change in crystal structure there.
I was going to ask you about optical glass manufacturing. When you talk here about the techniques you developed in the annealing of glasses, I was curious to know whether or not any of this was known to Zeiss.
I don’t think so. It hadn’t been published anyway. The first mention in the literature was in this Japanese Journal –- “M.” So, I guess was the author. He wrote an article on these heat emissions and absorptions.
I see. What sort of annealing techniques did Zeiss use then?
I don’t know.
It’s really not fair to ask since you weren’t at the Zeiss works.
[I would guess it was] a program of cooling; probably they just empirically found that a certain rate of cooling would anneal the glass. We were wanting to study the optimum temperatures and times, and rates of cooling at different temperatures, so as to make the process efficient and get it done in as short a time as possible and still get a good product. So we were interested in the rate of relaxation of these internal stresses. We studied that from different points of view — the stresses in elliptically polarized light and when they disappeared and how they varied. Then we tried out this differential thermocouple.
Let’s see: how do you determine whether or not stresses are present using thermocouples?
That’s sort of separate.
This was a technique that was used simply for measuring the temperatures of the…
Of the softening of the glass to see if there was any way of indicating where it rapidly softened so that you could anneal it quickly. This heat absorption on heating was quite definite and indicated a temperature at which you could hold the glass for a short time to relieve the stresses and then cool it from that. We were studying what rates would be advisable at different temperatures. In fact, when the glass is quite rigid you can cool it rather fast, just so it doesn’t break, without introducing additional stresses when it’s down around 200 or 300 degrees.
So at that point you can have it undergo a process very rapidly.
You can speed up the process there.
And these techniques really became well established then. I mean they were just beginning to be developed in 1917 or so.
As far as I know, before that it was just cooled slowly all the way down from some high temperature, right down to room temperature, without trying to optimize it.
One therefore learned how to vary the periods of cooling or vary the rates.
This would also depend on the size of the sample. We made experiments on that.
Yes, of course, depending upon the surface area and volume. And I can certainly see what you say here: that the study of the phase transitions in iron and glass were most important for your future work.
In fact, the work in iron suggested to me trying out something like that with the glass. Some of my associates thought that that was silly, that glass was just an undercooled liquid and there wouldn’t be anything showing up in the heating or cooling of glass.
I see. Really it seems almost as if at the National Bureau of Standards you developed much of the feel at least for the experimental work that you did later when you came to Minnesota.
So the Bureau of Standards work was certainly very important for learning experimental techniques and with respect to the exact type of work that you did there.
Did Swann and Tate initiate the Ph.D. degree at Minnesota in physics?
Probably not. You see, Foote got his Ph.D. in 1917. Tate was here then, but Swann came in ‘18. I don’t know when the Ph.D. work was started. That was before my time.
But it couldn’t have been started that much earlier, could it? I just don’t know when the Ph.D. programs were really getting going in this country in physics.
It probably wasn’t much earlier than that. Erikson has a history of the physics department that Nier has now in his office written by Henry Erikson. You can probably find that information in it.
I wasn’t aware of that.
He has a hand-written, very elaborate history of the physics department from the earliest days. He was in the department from 1897 till 1939.
Well, that would be extremely interesting to look at. And you say that Professor Nier has it in his office right now. Well, I must ask him about that and see if he will let me look at it and examine it. That’s very interesting. You say that Erikson had recently spent a sabbatical year at Rutherford’s Cavendish Laboratory. Erikson must have gone to the Cavendish just when Rutherford did almost. Rutherford went to the Cavendish in early 1919 from Manchester, and so Erikson must have been there just when Rutherford was getting himself established.
(looking at references) Ph.D. 1908 at Minnesota; student University of Chicago 1899; Cambridge U, l908-‘09. But his Ph.D. was in 1908. He had a bachelor’s in electrical engineering in 1896. Then he joined the physics staff in ‘97.
So while his Ph.D. wasn’t awarded, according to this, until he went to Cambridge, nevertheless he could have had a sabbatical at that period, because he was at Minnesota before that period of time. During that period of time Thomson was still the head.
Yes, maybe I should skip “Rutherford’s Cavendish laboratory,” and say “he went to Cambridge.” I know he worked on radioactivity and conduction through gases. They were active in that field at that time.
Of course, let’s see — when did Thomson win the Nobel Prize, in 1906, I believe. So it was right at that period of time. And Swann was here from 1918 to 1925 at Minnesota, and you say he was the principal thesis adviser. So any graduate student that came in would immediately go to Swann.
Swann put him to work right away before classes began. He had a lot of research topics outlined, and he would let us see these and select what we wanted to work on. I chose this one on piezo-electricity. In fact, the research outline he gave me didn’t say anything about iron as a magnetic analogy. It was just on constructing a seismograph for detecting earth vibrations, and that Rochelle salt was a good material, but there were a number of anomalies noted in its behavior by Cady and Anderson and one ought to look into that.
So Swann seems to have had a tremendously fertile imagination for possible fruitful research topics.
Yes, he had quite a few on hand.
I’ve just noted — and I think we’ve already explained what my qualm was — that here in Minnesota the textbooks that you used, Jeans’ Dynamic Theory of Gases, and Richardson’s Electron Theory, were quite different from the ones you used at Case, and that was because Minnesota had a graduate school and Case didn’t at that time.
Now, this is a very interesting remark that you made here, that Professor Swann was critical of quantum theory in 1919 and 1920.
Yes. We students wished that he would teach us some quantum theory instead of just giving us some criticisms of it.
I see. Was this the whole quantum theory or did it focus on, say, the wave-particle duality in light. Was there any discussion of Einstein’s views, for instance, on the nature of light in this period of time that you recall?
Well, it was largely on things like electrodynamics and radiation that Swann approached from the classical electrodynamics point of view and felt that the quantization, arbitrary quantization, and non-radiating orbits and things like that were foreign to classical theory.
So at that period of time he was still highly skeptical of the Bohr atom, for example.
He was rather skeptical, but as time went on he changed his point of view. He published articles on wave mechanics and things of that kind.
After 1926 and ‘27.
Yes. Particularly in 1919 and ‘20 and ‘21 he was rather skeptical of the arbitrariness of quantum theory.
I’ve read in one place where Bohr’s theory seemed to make good sense as far as the spectroscopic applications went, but it didn’t do anything for the chemist. I mean it didn’t explain anything in terms of the chemical binding, chemical bonding, and the things that the chemists were really interested in. Is that accurate as far as you know?
Of course, throughout this period of time, really, I think, up to the Compton effect, people were very skeptical of light quanta; and Bohr himself even as late as 1922, just before the Compton effect, was very skeptical of light quanta. I was wondering if that was really what you had in mind here when you say, “one type of theory on Monday, Wednesday and Friday and an inconsistent theory on the other days.”
Yes. Swann was just studying relativity then, too, and he often said he wished he could get the ideas in his bones so that they’d come natural to him.
You mean special relativity or general relativity?
Both. He taught a course in relativity. I took that.
And the ideas in special relativity he still found very unnatural as far as he was concerned, let’s say noncommonsensical or something. Would you say that?
No, he just didn’t find it natural to talk about them. I think he wasn’t immersed enough in the subject to not have to make frequent references to his notes.
Your choice of thesis subject — we touched on this before — you said that you chose to study piezoelectricity. Did this represent a choice that really, stemmed out of your National Bureau of Standards work?
No, I was interested in crystals. It appealed to me — to study the properties of crystals. As I’ve said here, I’d taken courses in crystallography and optical mineralogy at Case, so I rather liked to work with crystals.
And this was the only thesis topic that Swann had that ...?
Oh, no, he had several, I don’t remember now — on residual ionization and recombination of ions, and things like that.
But this was the one that appealed to you most out of those that were there. Now, Professor Swann called your attention to the work of Anderson and Cady. I’m wondering — did Cady or Anderson make any efforts at interpretation of their observations?
Not in these reports. These are just reports of experimental findings. Swann had copies of them. I took notes from them. I still have the notes.
Really? You still have the notes that…
That I took from Cady’s and Anderson’s report.
That would be very interesting, too, to look at them. Sometime it would perhaps be very worthwhile to write up a summary of your discovery of ferroelectricity. It would be very useful to make some sort of a summary of it. We also touched on this before — that Professor Swann suggested that some of these effects resembled the magnetic properties of iron. This was a remark that he made to you?
He made that as a remark. This was not in his mimeographed outline of the research. That was mainly concerned with constructing a piezoelectric seismograph and using Rochelle salt as the electromechanical transducer. He just threw out the suggestion: that the properties depending on previous history and so on resembled the properties of iron.
So as it developed, it was more or less of a lucky guess or something like that, sort of a lucky intuition.
Yes. Oh, he was a brilliant man. He had a lot of bright ideas on things.
When you talk later on here, that you were so familiar with magnetic hysteresis. It’s very interesting that you were working with magnetic hysteresis in iron.
I was, incidentally, an assistant to Professor Zeleny. We had an experiment on hysteresis in iron; and so I had the apparatus set up for the students, and I made observations with it myself.
So you were very familiar with the phenomenon of magnetic hysteresis in connection with working with your students in the laboratory.
Now, as I understand it, Cady’s work dealt really with the piezoelectric response as a function of the applied pressure; and then your discovery really was not that directly related to this work in that you dealt with the variation of D with E.
More like Cady’s work. Cady studied the dielectric properties. Anderson found that these charge and discharge throws were unsymmetrical in different directions and found a saturation, a sort of a tendency to a maximum, a sort of a nonlinearity in response.
And so you then set up your apparatus, as you say, to extend the work of Cady and Anderson and to see whether or not there was something new in that respect.
Yes. I looked immediately for hysteresis loops. I thought I could test that out right away.
Hysteresis loops in D vs. E?
Yes, in Rochelle salt crystals.
So this had immediately occurred to you — that these effects did perhaps indicate a hysteresis. And this was the first thing that you looked for.
This was the basic purpose of setting up your experiment and going ahead with it.
We mentioned before — I just made this marginal note over here — that the work of Cady and Anderson was a straightforward report of experimental data with little attempt to interpret results. Is that accurate?
Anderson thought that he could account for some of the anomalies by electrostriction playing a part.
Electrostriction — meaning an electrical contraction?
Contraction of the crystal with an applied electric field. He thought that would influence the charge and discharge throws. He, however, ended up by saying he wasn’t able to account for the effects by either a piezoelectric effect or electrostriction.
And in forming an underlying theory, let’s say, of the hysteresis that you observed you focused on the water of crystallization of Rochelle salt.
Yes, the humidity seemed to affect the properties very much, and somehow alcohol would enhance them. I thought that would be an effect on the water of crystallization in some way, too.
The molecular constitution of Rochelle salt was well known at that time, although its crystalline structure…
Its crystalline structure wasn’t known, but it was known it was tetrahydrate of sodium potassium tartrate. In noticing the humidity effects, I tried drying the crystals and weighing them, and I found there was a definite change in weight, a decrease in weight as the crystals dried out. And the dielectric anomalies and the piezoelectric effects decreased, and so it seemed that water crystallization had a lot to do with the phenomena.
So that it seemed that when a theory would be produced to account for it, that the water of crystallization would enter in in a very definite manner.
Yes, Kurchatov later developed a theory in which he accounted for the ferroelectric effects due to the water of crystallization.
Now, Kurchatov became interested in it in the early l930s, as I gather.
And was there no work to your knowledge before that period of time on ferroelectricity in Russia? Kurchatov was in Russia at that time?
Oh, yes. I don’t know when he began his work. The first I knew he had published a monograph on “Siegnette electricity,” he called it, in Russia. He presented the experimental results and his theory in that monograph.
Do you recall where Kurchatov was working? Was he working in Moscow?
I think so. I have a copy of this monograph; it’s in Russian.
It sounds as if you have a magnificent collection of reprints. It was interesting for me to see how the name ferroelectricity was finally arrived at.
That is mysterious. The first time I saw, it was in Mueller’s article or pamphlet on dielectric anomalies. This was a result of a paper given at a conference before the New York Academy of Sciences that was published in 1940, and that’s where I first saw the term ferroelectricity applied to these dielectric anomalies in Rochelle salt and also in other crystals that had the same properties, like potassium dihydrogen phosphate and potassium dihydrogen arsenate. These were discovered in Scherrer’s laboratory in Switzerland.
That’s Paul Scherrer.
Yes. They have no water of crystallization, but they do have hydrogen bonds, and Mueller discusses this theory of ferroelectricity from that point of view.
What Mueller was this?
Hans Mueller — MIT; I believe.
I can certainly see now, since the properties are intimately related to the water of crystallization, how temperature and humidity and electric stress…
One can vary those during the work.
Are there things that you would like to comment on as far as the experimental difficulties involved in carrying out your experiment in addition to what you have mentioned here?
Well, one of the difficulties besides the variation of these different parameters was the difficulty in getting reproducible observations. And I tried various electrodes. I mostly used tin foil attached with shellac, but I also tried squeegeeing on some amalgamated tin foil using no cement other than the mercury. Later on I tried mercury cups attached to the crystal.
A mercury cup cemented…
You make a little reservoir on each side of the crystal and pour mercury into it and use that as electrodes.
And the results were really very sensitive then to even the electrode connections...
Yes. Yes, the shellac-attached electrodes seemed to be unsatisfactory from the point of view that as the alcohol dried out — the shellac dried — there were changes in the observations: maybe some of the effect of the alcohol on the water of crystallization and also probably a change in the electrical conductivity of the shellac as it dried. So they weren’t very satisfactory. I gave them up after a while.
Now, you mention here that really in spite of the great analogy to magnetic hysteresis that you did not suspect the existence of Curie points as you did the work. When were magnetic Curie points really discovered? Do you recall?
No, I don’t.
But you set up the work involving the temperature variation really as a result of your National Bureau of Standards work.
Yes, I was sort of oriented toward variations in temperature and just tried it out on anything I worked with.
Well, this was one case where really very remarkable results were found. So just out of your curiosity to see whether or not something might turn up with respect to temperature variations, you did these experiments. What was Swann’s reaction to this work? After you had found the magnetic analogy or the hysteresis loops, did he then react with some further stimulus, pursuing the magnetic analogy or something?
Well, he was very interested in the results. As I said, he presented my paper before the American Physical Society in April 1920 — I think it was in Washington. Then he recommended me later for a National Research Fellowship.
The National Research Fellowships were established when — right after the war, weren’t they?
I think so, but I’m not sure.
Was it customary for a National Research Fellow to remain at the same university such as you did or was it more common to go ...? [Actually, one of the conditions for acceptance was to change universities, but exceptions were made.]
I don’t believe it was common to stay at the same university, but I preferred to do that.
Well, you had all of your equipment there.
I had my equipment there, and I was going to continue some of this same kind of work. And so it would mean a lot of repetition of setting up this and that if I went away.
Yes, it was certainly very easy for you to just continue since you apparently were determined to pursue the work that you had developed earlier. It was natural for you to remain at Minnesota.
And here again, as far as your remarkably short period of time to get a Ph.D. degree…
Well, I had a start at the Bureau of Standards — two years of laboratory research — and then I took that course in physical optics from Ames of Johns Hopkins University. They were giving us extension courses at the Bureau of Standards, and we were released for part of the time, those of us who took the courses. So I had some credit there, and then I also had done some work at Case beyond the requirements for a bachelor’s degree. So altogether I was able to petition for enough extra credits to satisfy the requirements for a Ph.D. degree in two years.
And, of course, the laboratory work itself that you had done at NBS made you well oriented toward laboratory work by the time you arrived at Minnesota. So there wasn’t any traditional period of adjustment there, was there?
No. It was quite a different arrangement from what we have now. Now the students are apt to take courses and finish their course requirements and then start research. When I came to Minnesota Swann would immediately have us select a research topic before starting classes and get us started in the laboratory before we took any courses.
On what sort of basis did a person select a research topic? I mean the list was there, and the one that struck a person’s fancy was the one selected?
Was that sort of procedure common at other universities, too? Or was that Swann’s personal technique?
I think it was Swann. Once he got us started, he’d give us a free hand, and we’d go on, but he would come around every now and then to the laboratory to see that we were working and what we were doing and the results we had.
But you were really rather free to do what you wanted to. He would come around to the laboratory and offer suggestions and comments. How many students were there at that period of time?
There were about nine graduate students, eight or nine.
And he was really the thesis adviser for all?
He was thesis adviser, yes. Then Tate took on more and more of them in his line of work –- electron impact phenomena. And after Swann left there was more research done in theory under Van Vleck and Breit.
Was Drude’s book on optics the optics text at that time, would you say?
Yes. I used it in the German edition, the newer edition. There was an old edition in English, translated by Millikan and Mann, and that wasn’t as complete as the new edition in German.
You, of course, read German fluently.
So you used it as a reference. You didn’t expect your students to know German, or did you?
No, I expected the students to take notes and refer to the English translation.
Were there other books in optics at that period of time? Well, there was Wood’s Physical Optics.
That’s right. I used that at Case.
But these were really the two major books in theoretical and experimental optics respectively?
Once again, concerning your work on the electric hysteresis loops, you determined by your work here at Minnesota your measurements of the indices of refraction, the temperature work, and everything else — that the hysteresis couldn’t be related to the common optical properties of the crystal. Is that right?
Yes, there was no transition, no discontinuities at the Curie point. I expected something there, but nothing took place.
To your knowledge at this period of time was there anyone else working on the piezoelectric effect on Rochelle salt right after the war?
There was some work done at Bell Labs by Nicholson using the complete crystal in a sort of hour-glass structure, and he used the whole crystals as a microphone and speaker and so on. But there weren’t any detailed studies of electrical properties except for mine for some years. Mueller attributes that effect to the fact that there weren’t any theories and that the crystal had not yet been used very widely in microphones and phonographs, pick-ups and things like that.
I see. So here was a case where there really weren’t any good theories to account for these effects. Now, were there any attempts then to apply the new quantum mechanics at all to ferroelectricity?
And I believe that it’s only been rather recently that quantum mechanics is being applied to ferroelectricity.
Now, are there other points that come to your mind that you would like to mention or talk about regarding your discovery of ferroelectricity that you might want to bring out in addition to some of these things? It’s very fascinating and important to understand exactly as close as possible how you made your discovery.
I think we’ve covered the points. There was that suggestion of Swann’s that the saturation of polarization and the dependence of the properties of Rochelle salt on previous history of treatment of pressure and electric fields resembled in a way the magnetic properties of iron, and so I set out to investigate that and looked for hysteresis loops right from the start. I set up the apparatus with that in mind, and of course I found them, and then in varying the temperature that you only got this hysteresis effect between certain temperatures that I called an upper Curie point and a lower Curie point. I also plotted the electric susceptibility against the reciprocal of the temperature as Weiss did and found what could be interpreted as the succession of straight lines that I thought were as definite as Weiss’s curve for magnetism. So that seemed to substantiate the magnetic analogy.
Turning to some of the other discoveries in this period of time after 1920, was wondering whether or not you had any recollection — Well, there were a number of theories on the nature of light that were put forth right after the discovery of the Compton effect, G. N. Lewis had a theory; de Broglie had a theory. Do you recall any of the excitement or any of the responses to the Compton effect at this period of time? It really came as a shock. Is that right?
Yes, it was quite a shock to have the particle aspect of light being brought out so definitely and conclusively. It sort of threw some doubt on the well-established wave theory.
Yes. Now, Millikan had, of course, verified the photoelectric effect in 1916, but he himself in his paper — it’s very interesting — doesn’t interpret his experiments in terms of Einstein’s theory. Now, was that a common thing? I mean at that time was it true that the photoelectric effect wasn’t really regarded as conclusive evidence for Einstein’s light quanta? Do you recall anything of this?
Well, it was shown that an electron couldn’t absorb enough energy to be emitted as soon as it was emitted, and that the energy had to be concentrated in some way or localized. But that didn’t work out too well either.
Yes. So it really did take the Compton effect to really indicate that here was a particle that possessed both energy and momentum — a very striking experiment. Now, you have mentioned here about Henry Hartig and that it was considered just bad luck that Hartig didn’t discover electron diffraction before Davisson and Germer. Could you elaborate on that?
He was working on the reflection of electrons from metals before Davisson and Germer’s experiments. Well, it was thought that he could have discovered electron diffraction if he had been more fortunate. I remember, though, when he was working on this effect on the scattering of electrons and reflection of electrons that Gregory Breit came into the laboratory once and discussed the effect with him and felt that the results could all be predicted theoretically, that there wasn’t any use in doing the experiments. And that was before Davisson and Germer had discovered there was something new in reflection of electrons, namely diffraction that indicated wave-like properties.
And was Breit thinking of de Broglie’s thesis, do you think?
I don’t think he was. That probably was before. When was de Broglie’s thesis published?
I believe in 1924.
This was probably before that, or about that time.
Is Hartig still living?
No, he is not living now. He became head of the electrical engineering department at the University of Minnesota and was chairman there for quite a few years.
Do you recall any of the response to, for instance, the Bohr-Kramers-Slater paper and its idea of nonconservation of energy? Was this really regarded as a wild idea? It apparently was taken seriously by quite a few people. Do you recall any of that?
No, I don’t.
You mentioned here that Professor Swann was a pioneer in cosmic ray research. What was his attitude, if you recall, toward the great Compton-Millikan debate? Do you recall any of that?
No. He wasn’t sure what the residual ionization was due to. He was studying the effect at first of whether it was due to some radioactive contamination in the soil or something like that, and he had one of his graduate students taking ionization measurements on a raft in the Mississippi River far from the land there.
So he almost discovered the latitude effect!
Of course, he studied it in various closed chambers. He didn’t do any balloon experiments. But he was interested in the variation of the intensity of the radiations at submersion in various depths of water, too — when we were thinking of the new building he wanted to construct a deep tank into which one could immerse ionization chambers and study the effect of ionization at different depths in the water. But he left before the building was constructed.
He went to the University of Chicago in I think you mentioned…
That was the same year that Compton went to the University of Chicago from Washington University in St. Louis. So apparently Chicago was really building up a very strong department at that time — under whom, under Michelson?
Gale was the chairman then, Michelson was still living.
And, let’s see, Millikan went from Chicago when?
I don’t know.
So Chicago was apparently being developed into a very strong department in that period of time and attracting a number of people. You mentioned here, too, the question of the continuous vs. the line spectra of beta rays — this is another rather remarkable instance, isn’t it, of Swann’s nose for problems.
Yes, it is. Could you then tell us more perhaps about the atmosphere in Siegbahn’s laboratory in Sweden? You mentioned that his guiding principle in X-ray spectroscopy was precise experimental work. Could you elaborate on this?
Well, he was the professor. As is customary in Europe, and especially in Sweden, they had one professor and many subordinates. The whole laboratory was devoted to experiments in X-rays except for some work in extreme ultra-violet spectra, multi ply-ionized atoms. There were many laboratories and an excellent shop, and Siegbahn himself designed the X-ray spectrometers and other equipment; had an excellent shop to carry out his ideas. Some of these spectrometers were more accurate than I had encountered anywhere even in optical work. He had, for instance, circles that were engraved by Askania works in Berlin for astronomical telescopes, and he built them into the X-ray spectrometers to measure angles directly to a second of arc and by interpolating you could reach to a tenth of a second.
But he didn’t have much patience for theory. He was really a dyed-in-the-wool experimentalist and a good one.
And he expected that if theoretical advances were to be made, they would have to be based ultimately on very precise experiments, and he was determined to supply those experiments.
Yes, That’s right.
I was wondering: in connection with your comment here on the increase in research in nuclear physics at Minnesota, could you tell us something about the rise and development of nuclear physics research at Minnesota?
Well, Williams came as a research associate with Tate –- I don’t remember the year. They got a grant from the Rockefeller Foundation to build a Van de Graaff. Even before that they had started some work on a 300 k.v. X-ray machine.
And this was when — in 1935 or so?
Probably thereabouts. Yes, about 1934 or ‘5. Williams and Tate started some work on nuclear reactions and scattering problems and things like that, using a 300 k.v. X-ray machine. And after that they got a grant to build a Van de Graaff, which is now in the back of the physics building.
You said “using the X-ray machine.”
They had a 300,000 volt (300 kilovolt) generator that was originally bought for the X-ray laboratory when I left for Sweden. And that was taken over for this nuclear work. And, of course, that expanded. They built the linear accelerator afterwards and got another new machine — Van de Graaff.
So right in the mid-30s it was Tate and Williams who were the instrumental people for really developing experimental nuclear research at Minnesota. Did you have people — colloquia speakers and what have you — come in from the outside at this period of time to discuss techniques of research in nuclear physics? Did you have the weekly colloquia as they do now?
Yes, we had weekly colloquia and probably some special lecturers, I don’t know. In the seminars they invited lecturers from outside.
So by the time the war came nuclear physics had really gotten off the ground at Minnesota. And then as soon as the war came, did most of the people then leave? Did you leave Minnesota at that time?
No, I stayed on teaching mostly soldiers and sailors during the war.
Mostly soldiers and sailors. Do you mean people who were about to become soldiers and sailors?
Yes. They were actually in service and were sent to Minnesota for a pre-meteorology course or science training and things like that. We had quite a group of men in uniform. Some of the regular staff members had left to work elsewhere. Tate went to New York and Nier had left.
Nier went to Los Alamos?
New York and Oak Ridge. We had invited people from other universities to help us teach these men in uniform. Williams had Bonner come from Texas, and they did some work on something, some secret nuclear research. About that same time Nier also separated U235 during the war and sent a sample to Dunning at Columbia who found it was the fissionable isotope of uranium.
Nier did this at Minnesota?
Yes. He separated some of this U235. The reporters got excited about the possibility of nuclear energy, nuclear explosions, and during Nier’s absence Williams was interviewed by one of them and he told them there wasn’t enough energy in it to spring a mouse-trap, thinking of the amount of uranium they had separated.
So, rather minute quantities but sufficient to determine that it was the fissionable material. This was when? In 1941, ‘42?
Probably about ‘42, yes.
Did Williams remain at Minnesota during the war?
No, he left for Los Alamos too after a while. He was here at the start with Bonner and someone else. They were working on the Van de Graaff. Blair also went to Los Alamos. Blair was a graduate student then.
He took his degree under Williams?
He took his degree under Williams, yes.
And so Los Alamos really at that period of time was the Mecca for nuclear physicists?
And then after the war did Blair and various other people come right back to Minnesota?
Yes. As I remember Blair got his degree on classified research he did. Some of us didn’t like that.
That very subject is making the news today. At a recent conference in Paris last fall I had occasion to talk with Professor Ivanenko, the Russian nuclear physicist, and I was impressed by the fact that apparently the development of physics and nuclear physics in particular developed in Russia very much as it developed in this country. That is, it got its start in the mid ‘30s, and by the time the war came on, information was being gathered on nuclear properties. During this period of time did you have any contacts with Russian physicists? You mentioned Kurchatov. Do you have any feel at all for the development of Russian physics?
No. The only contact with a Russian physicist I had was with Frenkel when he was here back in 1931 or ‘2 — James Frenkel.
He was here as a visiting professor?
Yes, for a school year after Condon had left. You see, Condon had replaced Van Vleck on the staff, and he remained for two years — about ‘27, ‘28 or ‘9. And then we had Frenkel for a year. He’s the only Russian physicist that I’ve been acquainted with.
Let’s see: Van Vleck left Minnesota in the mid ‘20s?
You mentioned many of the interesting talks that you had with Professor Van Vleck walking down the Mississippi. And just looking, in addition to Van Vleck, at the list of names that you have here — Gregory Breit, E. U. Condon, James Frenkel, Bardeen, Williams — there was really a remarkable cross section of people here at Minnesota. Would you like to comment on reasons for this? For instance, was it Erikson who really brought all these people in? Was he the guiding light?
I would say that he was the guiding light. Appointments are made through staff discussion and deliberation, but Erikson’s hand was very prominent in the selection of these people. Some of the graduate students that became distinguished are on our staff now. You will notice Hill, Nier, and the Freiers, Blair.
Again referring to Tate here, you mentioned that his lectures in theoretical physics were a marvel of perfection. It seems to me that most of the people that you mention here were rather remarkable lecturers and rather remarkable teachers so far as I know.
Yes. Tate attracted people from out of the department to his lectures. Mathematicians and engineers would come in to hear his lectures on theoretical physics. That was Tate’s course for many years, and it was taken by all the graduate students in the first year that they were at Minnesota.
Later on, was this the same course that Van Vleck was giving, or was Van Vleck teaching quantum mechanics?
He was teaching quantum mechanics.
Concerning Swann, his definition of the ether and the story about the colloquium where he was challenged to develop a theory really seems to indicate his personality.
Yes. There are many stories and interesting remarks in his book, Architecture of the Universe, published in ’34. These are just quotations.
Typical examples of his style of delivery.
Yes. Oh, he was a very interesting lecturer — very witty and had a number of amusing analogies in his lectures and in his book.
At this period of time, let’s say, was there any attempt made to give demonstrations and lectures as we do now in the introductory courses?
Oh, in general physics there were many demonstrations given — maybe more than now where we have only ten minutes before the lecture to prepare a demonstration. In the early days many of the lecturers would want the lecture room to themselves for the hour preceding their lecture so that they could set up the experiments and try them out and maybe put some notes on the blackboard. Now that’s all changed. These lecture rooms are used continuously with a ten or fifteen minute interval between lectures.
So it was very common for people to spend the hour beforehand setting up their own demonstrations. There was no one to assist them, I assume.
Oh, we had a caretaker who would bring out and clear away things — Charlie Johnson. He used to be a janitor, but he was so interested in the physical demonstrations that he was appointed by Erikson to help us with the apparatus. He didn’t know any physics. He was very enthusiastic and interested in all the effects, in the colored lights and things like that.
He was interested in the magic show.
Yes. And very obliging and helping to get things and clean up afterwards.
Professor Blair mentioned to me one time that in the design of the new physics building, it was Erikson, I think, who had the lecture demonstration equipment really at the center of all these lecture rooms.
And that’s not at all common in universities today. It indicates his really thoughtful planning of that building in many ways. We’ve talked about Frenkel here, and I’ve asked you about the development of Russian physics also; and we’ve certainly covered this last point about Swann’s ability to inspire people, his large amount of influence on a number of people. Are there any other things that you would like to think about or talk about? We’ve really gone the gamut. Well, I certainly have learned a lot from this, and I greatly appreciate your time and effort. So what we’ll do then is just simply conclude the interview. I guess I should mention that today is the 8th of May 1969, and this interview has taken place in the home of Professor Valasek at 300 Seymour Avenue in Minneapolis.
John Zeleny granted first Ph.D. in Physics in 1906 at University of Minnesota; the second in 1907 was granted to Anthony Zeleny.
Erikson himself says: “The writer was granted sabbatical leave for the year 1908-9. The year was devoted to a research on the recombination of ions at different temperatures in the Cavendish Laboratory, Cambridge, England, a problem suggested by Professor J. J. Thomson. Lectures by Professor Thomson and Professor Larmor were attended. Among the research workers in the Cavendish that year were: Kaye, Horton, Kleman, Laby, Vigard, Wellish, Satterly, Hughs, Widdington, Miss Laird, Crowter, Wright, Child, Beatty. The year was very inspiring. Rutherford, then of Manchester, was present at the Cavendish annual dinner and spoke of his experiences in the Cavendish –- ‘electrometer so sluggish he had to use an ax on it.’ Rutherford was on his way to Upsala to receive the Nobel Prize. Professor Thomson was knighted during the year. C.T.R. Wilson was obtaining his expansion chamber tracks at that time. Professor Thomson was one man making feeble light-exposures, looking for quantum effects. Wellish was doing his mobility work. Suffragettes were being carried by policemen from public gatherings.” Pp. 267-268, History of Dept. of Physics, University of Minnesota.
Erickson, in his University of Minnesota History, says “1934-35.”
Erickson says that the weekly colloquium was introduced during the 1915-1916 academic year. “The hours from four to six P.M. on Wednesdays were set aside for a meeting of the staff and graduate students.” University of Minnesota, History, p. 273.