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Oral History Transcript — Dr. Leonard Loeb

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Interview with Dr. Leonard Loeb
By Thomas S. Kuhn
At Loeb’s Summer home, Pacific Grove, California
August 7, 1962

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Leonard Loeb; August 7, 1962

ABSTRACT: This interview was conducted as part of the Archives for the History of Quantum Physics project, which includes tapes and transcripts of oral history interviews conducted with ca. 100 atomic and quantum physicists. Subjects discuss their family backgrounds, how they became interested in physics, their educations, people who influenced them, their careers including social influences on the conditions of research, and the state of atomic, nuclear, and quantum physics during the period in which they worked. Discussions of scientific matters relate to work that was done between approximately 1900 and 1930, with an emphasis on the discovery and interpretations of quantum mechanics in the 1920s. Also prominently mentioned are: Sam Allison, Svante August Arrhenius, Raymond Thayer Birge, William Henry Bragg, William Lawrence Bragg, Arthur Compton, Edward Condon, Marie Curie, Peter Josef William Debye, William Duane, Tatiana Ehrenfest, Paul Ehrenfest, Albert Einstein, Paul Darwin Foote, James Franck, Helmut Hasse, Arthur Llewelyn Hughes, Frederick Vinton Hunt, Mrs. Langevin, Paul Langevin, Irving Langmuir, Harvey Brace Lemon, Gilbert Newton Lewis, Hendrik Antoon Lorentz, A. C. Lunn, McClellan, Albert Abraham Michelson, Mrs. Millikan, Robert Andrews Millikan, Murphy, Jean Perrin, Max Planck, Ross, Ernest Rutherford, Mrs. Rutherford, Hertha Sponer-Franck, John T. Tate, John Sealy Edward Townsend, Harold Clayton Urey, van der Bijl, David Webster, Joseph Weinberg, Williams, Mrs. Bloomfield Zeissler; Academie des Sciences, British Association meeting in Toronto (1924), University of Chicago, Columbia University, Universitat Gottingen, and Solvay Congress (1911).

Transcript

Loeb:

[Loeb’s reconstruction of Planck’s route to the blackbody formula is here omitted] The French scientists at that time were very very closely, personally friends, Langevin and Jean Perrin were exceedingly close friends. Now some of this I got from Perrin, but most of it I got from Perrin’s close associates. You see, Langevin had been probably a pioneer in my field. His law for the mobility of ions acting with attractive forces and solid elastic repulsive forces, done in 1903 as his doctor’s thesis, was probably one of the most outstanding and advanced pieces of work in kinetic theory up to that time. It is amazing, and it is buried, because it was published in an obscure, or relatively obscure journal, and it was too mathematical. And nobody appreciated it for 20 years.

I read it, and couldn’t quite follow the mathematics. I rederived one special case of the law and then Hass two years later in Tyndall’s laboratory called my attention to the fact that what I’d done — I’d used some derivations of Thomson’s — really had rediscovered in a different way the same law which Langevin had deduced, only Langevin’s is more accurate. Now Langevin was the man who did all the theory in Brownian movements, which enabled Perrin to wake his discoveries. They were exceedingly close friends. Of course when I got to France during the war it was my desire, among others, to meet Langevin. Perrin, who was very good and introduced me to everybody, showed a great deal of personal reluctance, and the boys around him explained to me that there was a little coolness there. I will have to tell the story of the coolness later. However, he couldn’t personally introduce me, but he had someone else take me to Langevin at the time. I was working of course with Perrin. The story here is an extremely interesting one, and a bit scandalous I suppose, but it involves people of that era and it should be told. Langevin was married to an ambitious French society woman. Whether she belonged to the petty nobility I don’t know. But she was determined to have a salon, to have a big house. And poor Langevin had to spend an awful lot of time in industrial work, consultation, to make both ends meet.

This is one reason why he was not more productive. And furthermore, he was one of those peculiar people who just didn’t give a damn. He put it out, and if you wanted it fine, if you didn’t want it, well that’s all right… What had happened was that after Curie’s death, Langevin and dame Curie became very interested in each other. And there was a very intense love affair which developed. They in fact even had a little apartment together. And dame Curie was outraged at the way Langevin was treated by his wife. And when they couldn’t meet, they used to leave notes for each other in the mailbox. Now, it happened that Madame Curie’s name was up for election to the Academie des Sciences. This was the first woman who had been considered, and there was a great deal of opposition in the Academy to her election. Painleve, well the whole group around Perrin, Langevin, all of them, were trying to get her elected, and there was an opposition. Somehow or other Madame Langevin resented Madame Curie. These things were completely unknown to her. And she was determined to put a stop to this. So she had a detective, and the love letters were purloined. And Madame Langevin passed them on to one of the scurrilous afternoon slander (???) in France just before Madame Curie’s election came up. They published these rumors and innuendoes [break] — This threw the group in the Academie des Sciences the Langevin, Painleve, Perrin group into a tizzy. They were all very very close. So Perrin and Painleve I guess — he was later you know temporarily minister of war before Clemenceau — went to see Langevin, and asked him if this was true. I think Perrin himself was personally deputized. He was the closest. And he was to ask him as a gentleman please to tell them, because they would have to defend Madame Curie one way or another, and they had to have the truth.

Well Langevin, gentleman that he was, denied any liaison and any business at all, so this group came out in the decent press with a complete denial. Then, there were published the letters. And among the letters was one in which Madame Curie — he had told her about a dinner party at which his wife had made an exceedingly snide remark — and Madame Curie said “If I were you I’d have thrown that leg of mutton you were carving at her head.” This was published in the press; the leg of mutton letter. Well, they had one hell of a time getting her elected after this. And in consequence, poor Perrin felt that Langevin had betrayed him and his friends, and they weren’t on speaking terms. But Langevin was very peculiar that way. Strangely enough, master of kinetic theory that he was, he made a terribly serious but small mistake in a theory for recombination which was generally adopted, which you read about I guess in my article, which caused a great deal of confusion. Well we finally proved that that thing was wrong, and I went to Sommerfeld to make me feel easier about it. In consequence I had published a criticism of it. Then later I was to deliver a talk in Paris, which he didn’t know about commemoration of Langevin’s return. We had a physical rehabilitations laboratory in l914, the late fall of l944. I was a little bit reticent about it because of the fact that I had criticized something the great master had done, because to my mind he was really one of the great ones. For instance, Debye took the polar molecule theory directly from the dipole theory of magnetism. So paramagnetism was all Langevin. And in many of the quantum theory discussions. So he had an awfully hard time, and I asked people why he hadn’t retracted it. “Oh,” he said, “it was such an obvious mistake that everybody should have caught up wit it,” and he didn’t think it was worthwhile. But this is one of the peculiar quirks of these people. They have their big moments and their carelessnesses. Now those are the two episodes that I wanted to mention particularly, and I thought you’d like to have.

Kuhn:

I’m very glad to have them. Did you see much of Langevin?

Loeb:

No, I just met him once that time, and then once when he returned, and that was all. Rutherford I was a household pet of. Now this is not known to anybody, and I hope that on your record it won’t be open to the public. One reason for my being closer than my own mental achievements and stuff to Rutherford, aside from the association with my father and all this, was that when I was introduced to their household he had a marriageable daughter. And she was a very attractive girl, very nervous, very shy. I was rather innocent, and her mamma was a very formidable person. And I was in officer’s uniform, and also Rutherford enjoyed having someone to talk to. The rest of the boys were pretty gloomy. Chadwick was terribly depressed, and H. Robinson wasn’t very much happier, and I was so glad to be out of the war and back in the laboratory, and people were awfully nice and I was having a ball, you know? I guess that the daughter and mother sort of had picked me as a future son-in-law.

Now this never occurred to me. I was completely innocent of this, until right toward the end. And finally when Rutherford offered me a position, I was a little surprised. But I mean I had been very very close, like sort of a father. He always would liked to have had a son. I must say, that Rutherford was a very hen-pecked man. His wife was a real little shrew. In fact I once had a theory that all of the great physicists that I knew at that time, Millikan, Einstein, all of them, had wives that left something to be desired. In fact, the greater they were, the more shrewish their wives! They really were pretty difficult women. They may have taken good care of their men, but. And she used to brow-beat him. After dinner, he would get up. Rutherford — a great big tall, hulking man. In those days they tried to save matches, so he’d have to light his pipe with spill. They had a lot of spills on the mantel. He’d take his pipe out, he’d lean up against that mantel. It had the inevitable cold fire and it was cool in the house. And he’d stand in front of it warming his back side, sort of relaxing and talking and being genial, and she would just ball the hell out of him. “Get out of the way of the fire. Let somebody else enjoy it.” And so forth and so on. At any rate, as I say, he had some male to lean on, and he could talk to me in the evenings. And in this way, as I say, I got to know him fairly well.

He offered me this position. My reply at that time was that I was very conscious of the fact that the Americans were ace-high with the British at that time. On the other hand I was looking to a future. First I’m a loyal American. Although the British were our allies and I have great affection for them, I am an American. Secondly, I knew that the love fest between Britain and America would continue until the next economic difference of opinion. And I knew that if I came under the aegis of Rutherford, I would be in a very tight and difficult position. So, without knowing exactly how the land lay and why this was, I turned the thing down. And Rutherford said well he was forced to accept my logic. It would be a difficult situation. But then some little events later occurred which indicated from what quarter the wind was blowing. It was precipitated particularly when young Bragg — Willy Bragg — came. Somebody turned on the phonograph. I’ve forgotten what her name was, but a girl wanted to dance. She wanted me to dance with her. I’d taken her to one dance, or been at one dance with her. She didn’t dance very well, and I was sort of reluctant to, in a private house, just dance. So I was very nicely put in my place by young Bragg who gallantly got up and — Frankly I didn’t think much of young Bragg and never did. His father was the great man. You know of course the great thing of his father was that he had published in 1912 his book. … The doublet theory. Of course this was the subject of discussion in Millikan’s course on quantum theory and nature of matter and atomic physics.

We were all betting of course in favor, of the Thomson theory of the nature of X-rays and not on the Bragg. But when von Laue came out, Bragg was the first one to turn around. And the old man did it really, and gave much more credit. Now maybe his son was the boy who devised the apparatus, and no doubt really did contribute, but I think the old was the one who got the ideas. Because the old man really was terrifically ingenious, and he was always in the forefront of things. He’d lectured in Chicago around that time also. He was really a tremendous fellow, but the son never did measure up.

Kuhn:

You speak of the discussions in Millikan’s course about the doublet theory. Was feeling pretty wholehearted that X-rays were waves, or was there reasonable difference of opinion on this?

Loeb:

Millikan, for the sake of argument, tried to make a case for Bragg’s book. Actually Millikan had his tongue in his cheek when he did it, and all of us felt that J.J. Thomson’s — You see Thomson had developed that atomic model on the basis of the scattering. We all felt that it couldn’t be anything else but short wave lengths. … Incidentally, for your information, I had all my lecture notes, both the rough and the smooth, in Millikan’s and Michelson’s courses. King has then. … They were invaluable, because all of these questions were discussed there. Millikan of course, when I began work with him in ‘13, he had just come back at the end of ‘12 from his half year abroad. And so he was fresh from all these discussions. And in the course, which probably was a year later than that … l9l4 … he took up the question of Einstein’s theory of the pho-electric effect. And the great problem there was, on the wave theory of light, here you have a wave that’s spread out infinitely thin, and all of a sudden, the minute, the instant within measurable time, the light strikes that surface, a photo-electron may come off it. And this is impossible. And so he spoke of the Einstein aether string theory. And of course the Einstein law he was then trying to prove.

Now previous to that, attempts had been made in the X-ray field by Duve Webster, and I think by Duane or somebody, Duane and Hunt, but they hadn’t gotten very far. And I think then Compton and Hughes also did this — made an attempt at verifying the law. And they verified it very roughly. But Millikan as a matter of fact offered that problem to me as one of the ones, and then took it himself when I was foolish enough to turn it down. But I wasn’t foolish enough, because I always had a reasoned objective within my capabilities and field of experience. And the breaking up of an ion, and the chemical questions of clustering and so forth in ions was much more important and clear to me at that time than the quantum theory. While I mean I recognized the terrific discrepancy between the wave theory. Being a pupil of Michelson’s, I had to believe in waves. And at the same time I had to disbelieve in waves. It was a very difficult period.

Kuhn:

Tell me, when did you first do you suppose become aware of how fundamental the breaks in progress were? I remember you tell this story of your meeting with Arrhenius in 1911 in New York. That would have been what, just at the end of your period at Columbia, before you went out to Chicago.

Loeb:

Yes. I was referee, or not referee, was acting as abstracter for chemical abstracts when DeBroglie’s two papers this was after the war, 1921, around there were sent me for abstracting. The papers in which he set the wave lengths of the electron. Well, the thing that bothered me immediately was that the wave length of the electron in the DeBroglie theory was larger than the nucleus. It was larger than 10-11 cm’s. And yet beta rays came out of the nucleus. You see the world was absolutely — physics was full of contradictions. We just didn’t know that the electron was created in the act of radioactive transformation, that it was liberated. But we thought it was in an orbit or something, it was a constituent of the nucleus.

Kuhn:

Did people talk about those papers of DeBroglie’s quite rapidly in this country?

Loeb:

That was ‘21. This was you see after the conference. I’m just giving you a background of how we were faced with these. Now the 1911 Solvay Congress was the first time these new quantum things were brought together. At the end of the sessions, which Arrhenius attended, the arguments from the experimental and theoretical had been so convincing, particularly the experimental confirmation, that Arrhenius felt, because he was always a man with creative imagination, always daring, that this was going to be the most important thing in physics and chemistry. This is what he told me. It was not only Arrhenius, but I’ve been generally told by people at that time that the 1911 Solvay Congress clinched the quantum in the minds of the great majority of the progressive scientists. Now the question of relativity was a little more complicated there. When Millikan’s results came out, this was a very strong indication. When Bohr’s theory — Lemon gave Bohr’s first paper on his quantum theory.

Kuhn:

At the colloquium in Chicago?

Loeb:

Chicago. Of course Michelson was there, and Michelson didn’t react to it one way or the other. Before that, about a month before, Lemon had given Nicholson’s — I guess it was Nicholson’s theory — a Britisher, in which (neburion) and (protofluorine) were new elements which were giving these lines. …Well this thing made a terrific impression.

Kuhn:

I’d be terribly much interested in knowing more, if you could remember about reactions at that first report of the Bohr atom. Clearly there are a lot of people who really paid very little attention at the beginning.

Loeb:

Not in that laboratory. Realize that this was the leading laboratory. I think Michelson was interested, but Michelson wasn’t working in the new physics. As I indicated all along, Michelson was interested in his classical experiments. You read that section that I wrote Mrs. Stevens about Michelson’s talk before the symposium on relativity in Chicago? I can elaborate on that. Michelson accepted for example — his own Michelson-Morley experiment he knew to be correct — he accepted the Lorentz transformations. He accepted the Lorentz-Fitzgerald shortening. Beyond that he would not go. The rest of it was mysticism. We went further at that time in accepting relativity for this reason, that the Bucherer-Kaufman experiments of 1909… And it turned out that Bucherer’s experiments, they may have been faulty and all that — many of those experiments were — but they were uncannily lucky, fortunate for us. … Some of the Zeeman effect things happened to pick the right lines. Everything just worked this way, at the time when they needed to pick the right lines. And yet they didn’t do this purposely. It just happened. Some people have horseshoes around their necks. So I think that we were convinced about the correctness of the Einstein relation.

We didn’t I think fully appreciate it. But after the war, by 1919 — let’s see, Einstein’s general theory came out in 1913, but there wasn’t much said about it then. But by 1919 they had the data from the Campbell photographs of the light deflection of a star and all that stuff, and by this time it was generally accepted. This is the best I can say, people didn’t understand, they didn’t completely endorse it. They accepted these new theories. They accepted the discoveries. And certainly in Millikan’s school we accepted. You see one of the first things that happened, the Bohr theory was accepted very quickly, because right after that the Franck and Hertz experiments came, completely confirming the Bohr theory. I mean there was a little confusion as to whether the ionization potential, first excitation potential, were there, but the thing that was indubitable was that there was a discontinuity. You got nothing until you reached this frequency, which was exactly what Planck’s quantum theory said. And what the Bohr theory predicted.

Kuhn:

Let me ask you one question first, and then come back to this. I was delighted to see that your first talk to the colloquium had been on the Franck-Hertz experiment. I’ve very recently talked at some length with Professor Franck about the Franck-Hertz experiments, and I have a number of questions I’d like to ask you about that. First, do you remember, was Millikan at this presentation of the Bohr atom?

Loeb:

Oh yes, this was his colloquium. He ran the colloquium for Michelson. And so Millikan and Michelson were both there, sure, sure.

Kuhn:

And you think generally everybody was pretty impressed with this idea?

Loeb:

Well, we accepted the Franck and Hertz experiment! He did it two ways you see, there wasn’t any question about it. The only thing was, there was a little confusion as to getting ionization when they should have gotten photo-electric emission. And this was explained within a couple of years by the fact that there was secondary photo-electric emission.

Kuhn:

But you know, it wasn’t explained within a couple of years. At least it wasn’t generally. The first time that Franck and Hertz publish anything which relates these experiments to the Bohr atom, is in 1919, five years or more after the experiment.

Loeb:

In this country we were ahead of them then. I didn’t realize that. Now let me give the picture as I see it. Van der Bijl was a British-trained Dutchman who was at the Bell Laboratories. And he was an exceedingly acute fellow. And he explained the operation of the low voltage mercury arc on the basis of multiple ionization. He pointed out also that the apparent ionization of these things must be due to a secondary photo-electric emission. And he pointed this out at that time. Now he may not have published it, but this was in discussions or in a seminar at Ryerson. When was the Bergen Davis and Goucher experiment published? … I can tell you this, at a Physical Society meeting in 1917, John T. Tate gave his maiden doctoral paper. It was this April meeting — I guess ‘18. He had awakened one after another of the spectral lines with a spectroscope at the Bohr potentials. So already in 1917 there was experimental proof that these were lines, line emission, and Van der Bijl, I am sure … was the one who suggested this, but Tate used a different technique. He used a spectroscopic technique, as I remember it. And this endeared Tate to me. When I listened to this, why this just popped out, there it was! Then Compton very early came out with the idea of using asymmetrical electrode systems and then differentiate the photo-effect. As I say, these wee inelastic impacts were received and this was quantum theory.

Kuhn:

But not the Bohr atom?

Loeb:

Well it was what the Bohr atom said. We didn’t, at that time, attempt to differentiate between the ionization and excitation potentials on the Bohr atom. See, the Bohr theory was very sketchy and very primitive — the first papers. But it completely did what he predicted, there would be nothing until you reached a certain energy. This was the important thing. This was the thing that put the quantum theory across.

Kuhn:

When you reported on the Franck-Hertz experiment, would you have included this paper on the excitation of the mercury line?

Loeb:

No, this was their first paper, in which they got the inelastic impacts. That was the first paper that they published. That’s at least to me the more important experiment. They shot the things in the air and got them back with the energy loss, or didn’t get them back with energy loss. Then the other experiments were simpler and more accurate, and much more sensitive, but they were not as impressive to me. I think this makes it clear, and it had to do with the inelastic impacts. This was the first paper. This was the thing that came just about the time of the Bohr theory, or a few months later.

Kuhn:

This was inelastic impacts in mercury vapor?

Loeb:

No, actually their first experiments were in helium. … They tried helium. Then they tried hydrogen, and there the things were more messy. But in helium, the inert gases, they got very nice results. The mercury vapor of things came later, as I remember. The paper I reported on was in the spring of 1913. And that was the one where they shot it into helium and the thing bounced back. And then they did the other experiments with the retarding potential; but inelastic impacts. This was the thing that was the important thing, because this is what the quantum theory predicted. So, as I say, Millikan was already quasi-committed. Millikan was much more willing to accept than Michelson was, but Michelson was too preoccupied. Michelson was a man, not with a one-track mind in the narrow sense, but a man with a technique and a mission and a series.

Well I mean, the versatility of the man, measuring the diameter of stars, the making of the gratings. It was the Michelson gratings that were responsible for so much of the development of the vacuum spectrograph and Compton’s X-ray wave length measurements were Michelson’s grating. Not Woods gratings, not anybody else’s gratings. … Millikan was sold on the Bohr theory from almost the first. Lemon was not. (Lemon was not big shakes.) And we didn’t follow Millikan. I was always independent, but Millikan and I always thought the same way. This is why I went to work with Millikan. Here was a man who for the first time — I don’t want to compare myself with Millikan in any way — but here was a man whose mind worked along the same type, in the same way. Rutherford in a sense also.

This visualization without a lot Of mathematical paraphernalia, this sort of intuitive feeling. I’ve done this all my life, and my successes have been largely this way. And I’ve left it for other people to work out the accurate theory, people who have mathematical facility, and I’ve always been surrounded with it. But realize this, the dates of published papers are at least a year or two behind the discovery. … These things would be disclosed and discussed, and those of us who were alive would take these things up and we would discuss them, and sometime we’d tear them to pieces. I think Bergen Davis, and Goucher’s experiment must have come around 1918, I believe. Realize that already Mohler, who had been my housemate at the Bureau of Standards, had begun working with Foote as early as 19— well, ‘16 — they’d begun working on ionization potentials. By the time the war was over, these people had the complete works. They’d gone very far toward establishing a theory.

Kuhn:

What sort of contact would there have been between Van der Bijl at Bell, and (Ryerson)?

Loeb:

Millikan was very closely tied in with Bell Labs. I think they offered him the job of director, and his outstanding Ph.D., Jewett, one of the first few (somochromes) from Ryerson, took the directorship there. He kept very close to Millikan, and Millikan was continually consulted. Chicago was just as California now or began to be with the cyclotron and the developments and Birge — a mecca for visiting scientists. So in those days, everybody came to Chicago. And Millikan of course was a tremendous drawing card. So Van der Bijl spent some time around there. I mean I got to know him personally very well. He was the one who did probably the best scientific work, and wrote the first book on the amplifier and oscillator tubes. Before that you’d had de Forrest and (Winters) and everything had been cloaked in secrecy. Van der Bijl was a top-notch scientist. Then he went down to South Africa and became director of their South African research group, and he died very early. He was a very able man. Karl Compton was also very much up on his toes. Karl Compton was one of those who accepted the new things. But Compton was just beginning. Karl was there in ‘15, in Princeton. I think he must have gotten his Ph.D. around ‘12 or so, because he taught out at Reed College for a year or two. And then went to Princeton. And Compton was right there with the modern atomic theory. Both the Compton boys were pretty much alert, but Arthur was sort of off in a fog most of the time.

Kuhn:

You think there had been nothing of this same sort, of this same consciousness of novelty, at Columbia these same years?

Loeb:

Columbia was mostly probably very, very decadent, except for Bergen Davis. Bergen Davis was a live wire, but Bergen Davis was a queer old coot. He rubbed people the wrong way, and I think he was discredited — because he was modern. I think that the rest of the people looked down on him rather. I think Columbia in those days was pretty low. Bergen Davis I would say was the livest wire at Columbia. … A lot of those fellows, old timers, who were officers of the Physical Society got to be very close friends of mine. We always got along. But they were terribly conventional fellows. Lyman was really an old stick-in-the-mud, frankly. There was no creative imagination. And (Sabin), the sound man at Harvard. I remember when I was a second year graduate student in physics, he happened to be at (Woodshole), and we met.

He spent a whole evening quizzing me about Michelson’s courses and things of this sort. And then the fellow who later became president of Johns Hopkins, who was a physicist. Ames. These fellows were classicists. I think Ames was pretty much on his toes, but most of them weren’t — I mean, these were the fellows who drove me out of physics. They were purists. One of the live wires here on the west was Percival Lewis in Berkeley. I took a course in 1909 with him. And the first thing we did was to study Thomson’s electron theory. Another one that was very much a live wire was F. G. (Catrell), the (Catrell) process. All of these fellows, they’re in a class by themselves. They were the fellows that stood out. The general acceptance of the dissociation theory among the chemists was not widespread, Berkeley was better than most schools. Columbia definitely decadent, compared to Berkeley.

Kuhn:

Can you tell me something about the Ramsauer effect and the extent to which people were perturbed by it.

Loeb:

We weren’t perturbed by it, at least I wasn’t. As a matter of fact, it was exceedingly exciting and interesting. You see, the mean free paths had been discussed primarily through swarm experiments, the Townsend experiments. And these were of course purely statistical averages. We called them swarm experiments because what you have, is you start a swarm of electrons and measure the energy distribution and the drift velocity and all of these things. And from this you can also get, if you use the simplest mobility theory — I’ve forgotten who it goes back to, but it’s an exceedingly simple mobility theory of an ion moving, or electron moving, in a gas — you can get the mean free path. Now there were indications in Townsend’s work that the thing did vary with the velocity, with the energy of the electrons. There was no question about it in that work published by Townsend. Again that magic year, 1913. These things began to appear, although they weren’t realized. Townsend’s book came out in 1915 and there he publishes a table of variation with velocity, of electron free path, from the swarm experiments. Now it isn’t a radical change, and is inherent in the method.

But nevertheless it is a real effect. So there is number one. Naturally I was very familiar with this business. I was teaching a course in discharge through gases. I was also teaching kinetic theory and heat at that time in Berkeley. And we all accepted them. And of course Millikan immediately accepted them. Everybody did. I remember meeting Millikan in 1924 in London. He was talking at the University College, London. And I’d just been with Townsend. And Millikan was wondering what the difference between the Townsend experiment and the Franck and Hertz and the Ramsauer type of experiments, were. Because, he didn’t see that the difference had to do with a lot of collisions and the statistical average. The other one was individual collisions and much more detailed data. Millikan jumped on the band wagon. He had Brode do his doctor’s degree doing the Ramsauer effect, and I think he must have started around 1922 or ‘23 on his experiments, at Cal Tech. Because he came to us in ‘28, and he’d been at Princeton a year, and he’d been a Rhodes Scholar a year, and he’d been at the Bureau of Standards, so that takes three years, ‘28 to ‘25. He must have gotten his doctor’s degree around ‘25 or ‘24. On the Ramsauer effect.

Kuhn:

Now I didn’t realize he’d done it on the Ramsauer.

Loeb:

So you see these things were much more generally accepted by the forward looking.

Kuhn:

After ‘21, this was a quite generally recognized effect. There are some places, and particularly Gottingen, where people were a good deal perturbed about it, where it wasn’t simply that this was happening. They knew it was happening, but couldn’t figure out why the devil it was happening.

Loeb:

The theory I don’t know about. In fact the theory was done considerably later. In fact, it wasn’t until much later, when I was writing my atomic structure, or in that period, that I got hold of the papers on the calculations. And this must have been in ‘26 you see, or ‘28. … Before the wave mechanics, not any of these things were clear. All of these things sort of had to happen together. Some inkling of some of the historical sequence of these things you might get by glancing through sections of my atomic structure, which is a combination of Sommerfeld’s theory, his book Atombau, and my own development in the field as things happened. That and my development of physical thought. De Broglie’s first paper came out in ‘21 or ‘22 just before I came to Berkeley, and I remember it was sent to me. Abstracting it, I felt unhappy about it. But that was the first step. And then the next thing was the Heisenberg series, matrices. And Heisenberg lectured about those. You see then I was very closely associated with Condon. Condon was with us, and Condon was following these things quite excitedly, and he couldn’t make too much out of these matrices, and I couldn’t. And I couldn’t see how the matrices could be related to atomic structure.

Kuhn:

Was that Born who lectured at Berkeley?

Loeb:

No, Heisenberg. Heisenberg lectured on the matrices, matrix algebra.

Kuhn:

Because I know Born lectured on this subject in Berkeley first. I think in the early spring of ‘26.

Loeb:

Born came out there just as I was having a hell of a time with Hertha Sponer at that time. You’ve probably read that, I don’t know. I unfortunately was very close to the research fellowship people, and you see, being one of the first national research fellows, I was very close to the board. And anybody who was sent out to Berkeley to work was put under my tutelage more or less. Von Hoeppel, and later Sponer followed. And Sponer was a thorny person. She was a very opinionated little person, and she had been spoiled by Franck. Franck was god, and she was used to having her own way. And she had come to America with the idea of making money. But she was on a research stipend, and they told me specifically that she was not to earn money outside, that her visa and everything included this. And god damn it, that woman just drove me crazy.

She was just like a bunch of quicksilver in a little box, leaking out one corner and another. She was always getting her hands on lectureships and things that she was not supposed to take. And so I was her nemesis because I put a stop to a hell of a lot of schemes, because it wasn’t in the contract and it wasn’t according to Hoyle, and was told specifically that I was to see that this was not done. It was very unpleasant. So when Born came, he and I tangled on that question, about Sponer a good deal. I remember that. But Born’s lectures did not impress Condon or myself particularly Condon did go to work with him in Gottingen later, but at the time, there was no solution. Of course the great discovery before that was the Uhlenbeck-Goudsmit electron spin, which was very helpful. And then Condon came bouncing into my laboratory one day all uppity “We’ve got it.” And that was the paper by Schrodinger. He said, now there’s a man who has it. This is the thing. And using this, very shortly thereafter, Condon developed the Franck-Condon principle. No, Condon was exceedingly alert. Even more alert I think than Birge to these things. Condon had a very good grasp of theory. So I think it was really Schrodinger who showed the way. Then all these other things began to drop into place, you see. Everything just sort of tumbled right in.

Kuhn:

But matrix mechanics, at least at Berkeley, hadn’t done anything much for anybody?

Loeb:

No, not to the best of my knowledge, no.

Kuhn:

That was true at a fairly large number of places.

Loeb:

Yes, I’m very sure, it wasn’t until Schrodinger’s thing came out, then people… Then it was after that that people began to look back. Now are there more questions?

Kuhn:

You were in Chicago when the Compton effect was discovered. Was that discussed in colloquium, were you in on discussions of that?

Loeb:

No, by this time Chicago had gone to pieces. When Millikan left, which was I guess in the end of ‘21, beginning of ‘22, Chicago dropped to pieces. The symposia ceased. As a matter of a fact, as I say, it was so bad that everybody went off on vacations and left Swan, Page, and H.S. Wilson as professors, with myself the only representative conducting doctor’s examinations of students. (Gale) was tired out, and had gone away for a vacation. (Lemon) always went off for a vacation. And then a feud between Lemon and Gale started. (Lemon) started kicking Millikan’s and Gale’s courses and material out of the lower division, and tried to get rid of everything that he could. And Gale was bedeviled. Michelson was supporting Lemon to some extent. There was no leadership, no unity. Dempster was there, and Dempster and I sort of comforted each other and discussed our own physics, but there were no more colloquia, nothing. But the Compton effect. Let’s see the Compton effect first came out in ‘23, was it? ... Compton was at that time at Lloyd Schuh’s place in Washington University, St. Louis. That’s where he discovered the Compton effect. And the first discussion, the first awareness I had of the Compton effect as such was at the British Association meetings in Toronto in the fall of ‘21. I’d been abroad, and I came back via Toronto and attended the meetings. Duane was there and came out with the box effect theory, and Webster was there and believed in the Compton effect. At that time of course I was at Berkeley and Ross at Stanford, we were very close to the Stanford group. And Ross had shown me — in fact in ‘23 had shown me his photographs of the Compton effect, which were even better than Compton’s. They were perfectly beautiful, and Ross was a beautiful technician. So I was sold on the Compton effect.

Kuhn:

Oh, then you had heard about it before the British Association meetings?

Loeb:

Oh yes, I’d heard of it. I’m sure I’d gotten it from Ross. But at any rate, we heard the box effect, and I listened to Duane and I didn’t think much of it. I’d thought very highly of Duane. He’d worked with (Danysz) in Curie’s laboratory and so forth, but after that I had lost all respect for him. And that was of course the thing he bust Allison on. He put Allison on to testing it, and Allison found that the Compton effect was correct, and while Duane was away published a paper on it, so he was fired.

Kuhn:

Was that a fairly typical Duane performance?

Loeb:

Duane was a starved man. He was one of the bright boys. You see Harvard was something that everybody wanted to get to. Why they did I don’t know, because it was the burial place of physicists and not a live wire place. Harvard was the great university you see, in America, and everybody wanted to get to Harvard. So as I recollect, Duane had wanted to get a position, and he hadn’t, somebody else had, or there weren’t any positions. So he went over to Paris and Europe, and studied in various laboratories and published. And finally they brought him back under some position. And the man was hard put to it. Actually he was washed up by that time, and he hadn’t any creative ideas. But he had to make good, and I guess he was conventional. I don’t know how much quantum theory he had absorbed or anything.

Kuhn:

He was responsible for one quite interesting idea in the old quantum theory.

Loeb:

He was? Well, he must have done something abroad to get back into Harvard. But at any rate, when he got there he was either jealous of Compton or had to prove himself, one way or another, or else he had done some work which this disproved. But he was on the spot obviously. And therefore I think, fighting for his life and his prestige. And I think it was just the position he was in. I think he was a weak man, I don’t think he was a scoundrel. I think this was just one of those things. He’d gotten there and he’d stuck his neck out, and damn it, here was a whipper snapper disproving him, turning traitor. If my students do good things, get what I missed or something, God bless them. But when they apostatize and go into a camp where I know they are wrong and where they have been taught better and ought to know better, we take that very bitterly. I wouldn’t fire anybody for that, but I would make them take a second look.

Then if they could prove me wrong, this is fine. But, I don’t know, the sort of thing he did. I wouldn’t have fired him. Allison wasn’t the kind of a man you’d fire that way. He was too honest and too naive. He was just a damned good scientist, and Duane was fighting for his reputation. I think this is the story. I mean, the other fellow, (Wickhoff), who exploited him, was a different character. He was just simply out for number one and he didn’t give a damn. He did that all his life. But this was not the case with Duane, I think. It wasn’t noble of Duane, but you don’t maybe agree or admire a man for these things, but you don’t condemn him too much, because I think that he was just on the spot. I’ve gotten an idea that he was lonely at Harvard, out of it. I mean, that was an awfully snotty place, at that time. This was way back you see, this was before the good people got there. No more.

Kuhn:

Also, I take it the whole relation of American physics to European physics has changed a good deal since the first World War. You both watched this happen in America, you’ve also touched base in Europe often enough to watch the change in the reputation and knowledge of American physics over there.

Loeb:

Let me say this. In 1928 Franck visited us, and we talked. Franck was philosophically minded, as you may guess. At any rate, he said well, you Americans have a wealth of material, and you have an ingenuity and you have techniques. And you have developed terrifically rapidly in experimental physics, in fact you’re going ahead of us. But he said, you still must depend on us for theory, and you will for some years to come. Well, there were many reasons for this. The reasons I think I can tell you, if that’s what you want to know.

Kuhn:

Yes. I would be both interested in an analysis of it, but I would also be interested in illustrations of it. For example, you must have watched curriculum change at Berkeley over the years, to get more mathematics to the physicists. You must have been in on departmental discussions which have involved this sort of thing.

Loeb:

No, as a matter of fact, we’ve never been concerned by this. We recognized the need for theoretical physicists and, theoretical physical instruction, or mathematical physics as we called it in those days, with the advent of Gilbert Lewis essentially, and E.P. Lewis. As the quantum theory, the Bohr theory and these things came in. We recognized the need of this. Relativity I think did more than anything else to stimulate the need of mathematical physical knowledge. So it began to be fashionable and important to bring in a theoretical physicist. Now Wisconsin already had Max Mason. Chicago had A.C. Lunn, who was probably a misunderstood genius, and who was completely frustrated, because his one great paper with his one great idea was turned down by a journal. And he became bitter and never published anything and never did anything after that.

Kuhn:

Do you know what that paper was about?

Loeb:

King can tell you. It had to do with the early quantum theory. This I know, it had to do with one of the fundamental aspects of what later was to be very important in quantum theory. King can tell you that. You may know it, I don’t know it.

Kuhn:

I heard this story about Lunn before, King and I had compared notes on it, but I don’t think he does know. That is, I think he knows what the rumor is.

Loeb:

That is it. And it’s probably the only rumor; nobody knows exactly what his paper was, because after it was turned down, that was that.

Kuhn:

You had heard that story at Chicago though?

Loeb:

Oh yes, I knew Lunn fairly well. I took a course with him. It was a terrible course. He wasn’t a teacher, but he was a man who tried to set Millikan right, and he was a man who was way ahead of his time and a very clear thinker in these things. But people didn’t understand him. Lee Page was the more popular type of theoretical physicist. A.G. Webster. You see we’d had some theoretical physicists, and they were in classical physics, most of them. Even Freddy Slate was a good theoretical physicist, but more a precisionist and a perfectionist than a creative man. No, there’d been that kind. And the transition came. We had death of properly trained people in this newer physics, but we sent a lot of these young people abroad. The whole birth and rebirth in this country of American physics came with the National Science Foundation fellowships. National Research Council fellowships, and the International Education Board fellowships. Then we were able to take people like Compton, people like myself. As early as l9l5, before I got my Ph.D., I wrote to Compton and asked him if he could get me a job when I had my Ph.D. So I could just get enough to eat.

I just wanted to do research work. I didn’t want a future position. I wanted a chance to do research before I had to become a teaching slave. But what usually happened was that the minute you were appointed, well, they pushed all the laboratory courses, all the dirt, all the lower division courses on to you, and you had so many units of teaching you never could do any research. And there wasn’t any stimulus to research. We had many universities. We had several professors in physics departments, there was a very strict seniority rule. Everything was oppressing people. The reason I went to Berkeley was that they promised me promotion as rapidly as I deserved it, and there was nobody standing senior to me. And this is what I promised Lawrence. This is the way, this is why I went to Berkeley. I had an offer incidentally at Cornell. But at Cornell in the physics department there was a hierarchy. Until somebody was pushed up or died, you stayed where you were. That’s no future. There was no incentive. And I turned down an offer at Iowa University, T.W. Stewart’s place. There wasn’t any chance. And Minnesota. I mean these places were just impossible.

The only place with any leaven at all at that time was Wisconsin, under Max Mason and the man who worked on radiation laws — C.E. Mendenhall. They were good men. But Mendenhall was an exception again. He was a modern physicist. He was Millikan’s right-hand man on the Research Council. You can see by the positions they offered who the live wires were. R.W. Wood of course was another one of them. But there were all too few. Now with the research fellowships, these young men had a chance, not only the experimentalists, but the theoreticians had a chance. We sent Condon abroad, we sent Oppenheimer abroad. They were abroad together. We picked Williams to be a theoretical physicist in our department. It was an unfortunate choice because the man was an able teacher, he was a scholar, but he was afraid of himself. He had no confidence in himself, wouldn’t venture anything. He never got his doctor’s degree, but he did do an excellent job of preparing the boys for Oppenheimer. And it was people like Oppenheimer, and Van Vleck, these are all of this vintage. They were all research fellows. It was this that gave us — me four years, and others two, three years, — to become research physicists, to go away and study, to think and to browse and to learn, after we got our doctor’s degrees. There was just as much genius. Condon came from the sticks. The place was just full of these young fellows. Some of them turned out to be good, and some of them — well, some of my most brilliant men, as you may have read in my autobiography — oh, I guess you haven’t read too much of that — some of my most promising men, through personality traits, ruined their careers. They just didn’t get a chance because they were such prudes and things. So this is the way it went. We had to have imported people here, and of course when Germany began excluding the Jews and began excluding liberals, why they flocked to this country. So we had a natural heritage of good teachers. And then Sommerfeld and these people began coming over to see the experimental work here, and they brought students back to learn from them. You can’t build a new profession over night from yourself. You’ve got to, it’s a question of cultural growth and the contacts with Europe were very necessary. Now, we have plenty of our own. Because we’ve offered them a lot. (Holland Snyder) was one of our really good theoretical physicists. Do you know his story?

Kuhn:

I don’t, no.

Loeb:

Holland just died of a heart attack. He was very young. Holland Snyder was a Mormon lad up in Utah, very brilliant. He was in one of these snail Utah colleges, agricultural state colleges or something, one of their good students but not their best. Well, we took the Mormon boys because they were the hardest working and some of the best trained, well disciplined. They were strangely enough not neurotic, they were very sane, hard-working, normal kids. And they were brilliant, many of them. (Irring) is one of them. You know (Irring)? — chemistry — and quite a number of others who’ve done very well. We picked the best man from there, and we took a couple of others. But we had more than we could take from Utah, so Snyder was passed up for a teaching assistantship. Two years later he came to us, he said he’d like to be a graduate student. Oh no, he didn’t need a teaching assistantship, he’d made enough money. He’d become an assayer in the mines for two years, made quite a bit of money. He could support himself for a couple of years. So he went in to talk to Oppenheimer. He wanted to go into theoretical physics, and Oppenheimer looked at this tar heel.

His hair was kind of disheveled, he was real hayseed type. This fellow had been reading quantum mechanics on the side and relativity, and before he came through he developed a relativistic approach to something. I don’t know exactly, don’t remember exactly what it was any more, some of it was way beyond me anyhow. But he turned around, Oppenheimer got more interested. Instead of talking with him 15 minutes he talked with him three hours, and by this time he’d told him he would work on the subject for his doctor’s degree. The man proposed his own problem. He got his degree in about two or three years, a minimum of time. I was on his qualifying exam, public doctor’s exam, and he was just sheer genius.

We had this fellow, who was later one of the boys who was accused of being a spy. I’m trying to think of him — Joe Weinberg. Well, Joe Weinberg came to us from City College of New York, or one of those places. Joe Weinberg came to me as a beginning graduate student, spoke about some very esoteric paradox in kinetic theory. It was a very important one though, but very, very — He said he thought he had a solution to it. He’d been working on it. Asked me if I — well, this was way beyond me, but I recognized at once the man knew what he was talking about. Well, he came up for his heat examination two years later. And Bill Williams by this time had become an alcoholic and was off, periodically late for everything, and (Lenzen) and I started to examine him. And he said, “Oh, by the way, do you remember that paradox I mentioned? I solved it.” And he sat down, and started to give it. And about an hour later — we’d quizzed him on other things first, ergodic hypothesis and so forth. He knew this stuff cold — Williams came in just at the beginning of this. And he said, “What’s this?” Weinberg began over again. He finished. “Huh. You going to publish this?” “Yes,” he said, “I was thinking about it.” “That’s a very fine piece of work.” That was about all there was to it. Let me talk about Albert (Overhauser). He was an undergraduate student in one of my courses in atomic structure, and after he’d taken that he was inspired to take my course in gas discharges. And we came to a problem which had arisen, namely the certain deviations from Planck’s law in mobilities and mixtures.

The man who I’d first told about it, Debye, had suggested that it was a dipole moment effect. So I mentioned this to Condon. I had shown Debye around. And Condon then was very interested in it, and he gave a solution. When I was presenting it to the class, I said I wasn’t satisfied with this solution, that somehow it didn’t ring quite right. So Overhauser took it off. He was a senior student in physics. But inspired, having his interest stimulated, and being well-taught. He came back and he said, “As a matter of fact, Condon and Debye’s idea is okay, except they are already included in the mobility equation, so you haven’t solved anything by this.” “But,” he said, “this is the way it goes,” and he gave me the theory, and he published the paper as a senior student, on mobilities and mixtures. And the only thing that superseded it was — that was in ‘48 —, and I suppose in ‘58 or ‘60, (Piandi) and somebody went to the esoteric force interactions for doing some emendations on it, extending it a little bit. But this is a native American, not a German, he hadn’t come under German or French or any other I mean he’s a native American, a good product. Look at the fellow who won the Nobel prize who was at Columbia and then went to Oxford, for the hydrogen fine structure, Willis Lamb. Lamb was a product of our Berkeley group. It wasn’t Oppenheimer alone. It was Willis Lamb, given the opportunity. These fellows are the fellows that are to replace the Europeans. They came from our native soil!

Kuhn:

I never had the notion that it was a lack of talent!

Loeb:

The damned Germans used to say we hadn’t any talent! Listen, very frankly, they aren’t all Jews either now. I mean the supercilious snottiness of Franck and all of those Europeans. One of them that wasn’t superci1ious and wasn’t snotty was Sommerfeld, who was a basically great teacher, and he was great and liberal and fine, but these other fellows were terribly snotty. Einstein. Let me tell you a little story. I gave it verbally to King, but I think he didn’t get it on tape recording, maybe you’d better have this. It has to do with Einstein, it has to do with Millikan. It has to do with a party which might interest you. In 1921 Einstein came over under the Zionist movement, as you know. And he was not allowed to meet anybody, scientific or otherwise. He was just as a money-getting attraction, like a $100 banquet. He didn’t see any American scientists, as far as I know, until the following episode.

A great benefactress of the University of Chicago was a Mrs. Bloomfield Zeissler, a very talented musician, who had married into Chicago’s wealthy community and had plenty of money. She gave an Einstein banquet at her house. She was a close friend of the Millikans and of the University people. And Einstein had expressed a desire to see Millikan’s laboratory, so one evening I got a telephone call. I guess it was 1921, maybe ‘20 or ‘21, Einstein was over. Millikan said, “Leonard, will you come over to Ryerson at 9 o’clock tonight? This must not be told to anybody, but Einstein is going to be smuggled out of Mrs. Bloomfield Zeissler’s house through the servant’s entry. I’m bringing him over.” And he said, “My German is somewhat deficient. Will you translate for me?” So I appeared, and Einstein was ushered in. I was fascinated because, at that time Millikan had thirty students, at least. Graduate students, and all sorts of projects, on everything. I guess the vacuum spectrograph was going — everything. Well Einstein went around that laboratory, and Millikan would start to show him a piece of apparatus and start to tell him what it was for, and Einstein would anticipate him and tell him what he hoped to get out of the experiment. Einstein was still then in his prime. In about five years he’d gone, to pieces pretty badly, but at that time it was simply terrific.

Well, I met Einstein in ‘24 in Berlin, and that’s when I had gotten acquainted with the wife, whom I didn’t think much of. He knew my father, had met my father on that trip, twice, and they were very congenial. Einstein had an exceedingly sharp wit. He was almost as clever in his witticisms, and bitter, sometimes sharp, as Heinrich Heine, the German poet. He had somewhat of that characteristic. And I knew this, because my father had often quoted. They had exchanged letters a good deal, and he quoted things that he had said, so I knew the tenor of his mind. Einstein got back to Germany, and nothing more was said. About six or eight months later an interview of Einstein’s came out in the public press, in which he spoke about America and Americans and American science, and this, that, and the other thing. And there were these terrifically sharp, witty remarks of Einstein’s, cutting. Millikan came into my laboratory in the morning with the newspaper. And said, “Leonard, look at this. Einstein can’t have said those things.” I read them. I said I’m afraid he did. He said, “the incomparable ingratitude and unfairness. This is just incredible.” And Millikan was really peeved. I’ve only seen him peered off twice. Once when he faced Langmuir in the trial between Bell Labs and General Electric on the three electrode tube, which ended in RCA being formed. A compromise. They settled out of court. He came back swearing — the only time I’ve ever heard him use any foul words. He came back from that trip, being opposite Langmuir on the witness stand, he said, “That damned Langmuir. He lied.” But Langmuir wasn’t above lying. Millikan sometimes rationalized himself too, but this is neither here nor there.

Anyhow, he was furious about it. I was sure that the things that Einstein had written, had been given in that interview all right. It was many years later, and we were at a very interesting Sunday luncheon following Physical Society meetings in Pasadena. There was A.F. Joffe, H.A. Lorentz, Gilbert Lewis, Tolman, Birge, Millikan, myself. I was secretary of the Physical Society so that’s the way I got in on this illustrious gathering. Anyhow, this was a rather formal affair, but everybody had been having a wonderful — a lot of fun, on reminiscences. Finally, we’d talked about Einstein; we’d talked about physicists. It was wonderful and everybody was having an awfully good time talking about various people, and one of the things they asked about was Einstein. Millikan said to Lorentz, “Will you tell me something? Do you remember in 1921, after visiting my laboratory and seeing things there, Einstein wrote, gave an awfully nasty interview which was published throughout the American press about America and about science and everything?” And Lorentz spoke up and said that that was his fault.

He was innocently responsible. “He did write those things.” Millikan said, “He couldn’t have written those things.” “But he did, it was my fault.” Lorentz was a sweet old character, a wonderful person. He said, “Well, I had a niece who married a German army officer. She was widowed in the war, and she earned a living in a depression Germany by doing newspaper reporting, syndicated. I never thought of her in this way, but she said, ‘You know, I’ve always wanted to meet Einstein.’” This was just the time Einstein got back from this American tour. He said, “Why he’s a good friend of mine. I can arrange this for you.” So he gave her an introduction to Einstein. And she just lowered Einstein — into this — just told him — she got to talking about America, got his impression, and she took down these things, these witticisms. She had a sharp memory and took them down and gave them to the press. But there was another sequel which I think might amuse you, because it also is for the record.

This conversation had been going on in this key. We’d talked about the great discovery, just the sort of things you’re interested in. Finally Mrs. Millikan got terribly bored with all this, and she looked up and she said, “Robert, I think we have had enough science. Let’s talk about something interesting.” There was a silence. Nobody said anything for about five minutes. Then in order to start the ball roiling, she turned to her son Glen and said “Glen, what was the Sunday school lesson today?” I looked around the table, Joffe’s moustaches were twitching and his eyes twinkled, and Gilbert Lewis’ moustache was twitching and his eyes twinkled. Tolman sort of looked over this way. And Millikan’s face got perfectly livid. It was the funniest thing. It took about fifteen minutes before the conversation got going again. So you understand when I speak about the wives sometimes! Did you know much about Ehrenfest at all? … He was a terrific character. For some reason he took a personal liking to me. He visited Berkeley. He was a very simple soul. And very emotional. So when I went to Europe he asked me to visit him. I spent a week there. And he had a bed where all the physicists slept.

It was up on the top floor, and there was a wall, and everybody who slept there had their name written on the wall. I think you, noticed that in my diary, biography. There was Rutherford’s name, there was everybody’s name! It was really quite interesting. Well I had just one episode that was interesting. He was married to a theoretician, Russian. … And we went off on a trip for a couple of days. I went to Einhaven. We arrived back very late at night. Their living room consisted of a grand piano and a blackboard and a couch opposite the blackboard. Here was the piano, here was the blackboard, a big long thing, and here was a couch. The house was all ablaze. The cooking was terrible and the house was always untidy. It was obvious there were two geniuses in it and nobody took any care. They were too poor to have any servants apparently and what little was done she did I guess. Anyhow, here he was stretched out on the couch, and she was up at the board writing a lot of equations. And he said, “No, no, that is not right. And they were having one hell of a mathematical argument at 12 o’clock at night, which we unceremoniously interrupted, but it was so characteristic. He was gay, and then he’d have terrible fits of depression. I wasn’t surprised, under the circumstances, he took his own life and his crippled son’s. But he was quite a character. Now he was another one who did not scorn America. Now, some more questions.

Kuhn:

Now I’ve been told that J.J. Thomson held out a long time on the isotopic interpretation of the two neon lines in the mass spectrometer.

Loeb:

No, J.J. I think suspected them and when the isotopes were discovered I think he was very happy. No, the one thing that Thomson was unhappy about, always was, he wanted a static atom, because he had been basically chemically trained initially, and he liked nice little hooked valences localized in atoms. This is where he went wrong, it was the static atom, but he did not go wrong on isotopes. No, to the best of my knowledge, does that set your mind at rest?

Kuhn:

I was really just groping to see whether there were particular controversies in the sciences during the period you were in England.

Loeb:

No, there was no controversy or anything. The one thing that Rutherford was unhappy about was that so far an oxygen 17 had not been discovered, but then, after all, if it was produced in this abnormal way, heck, there wasn’t enough of it to expect to find it right away. Giauque and Johnson came out with the oxygen 18 in 1926, and immediately … Menzel and Birge came out with a suggestion that there should be a — you had to recalculate the atomic weight of hydrogen. If this were the case, there must be a heavy hydrogen. And it must be present — from the data they had — one part in four thousand, which is precisely what it turned out to be. And then (Urey, Brickwedde, and Murphy). And Urey should not have gotten any more credit than Brickwedde and Murphy. Urey just took the idea of Menzel and Birge and put it in. Well, I met Urey in Berlin in ‘24, and I thought he was a big over-grown bullfrog. I didn’t think much of his originality or anything. He just was quite an advertiser, an opposer, and an appropriator. I thought that really his great discovery —. And then the way he acted when it came to the question of naming deuterium or something. Lorentz as usual was a big man, and Urey was a little, small, opinionated pig. Well, he speculates wildly, and. when a person guesses enough he’s bound to guess a few things right. But I haven’t ever felt that he was a great profound thinker. And I don’t really know what he has done.

Excuse my prejudice in these matters, but my evaluation of him —. You see, then it was Washburn at the Bureau of Standards who suggested that the reason why they hadn’t gotten hydrogen in Asten’s experiments was the fact that electrolysis liberated the light hydrogen and left the heavy hydrogen behind. And Gilbert Lewis immediately thought, well, the storage batteries we’ve had around here for 30 years should be wonderful sources. So he — he was the first one to prepare it in quantity, you know. But you see how these things work together. And if you’re sort of reading the literature and playing the field and watching, you see how these things work together. And it’s just a question of timing. Washburn by himself, if he hadn’t had to do other things at the Bureau, might have had the leisure to take this stuff out and separate out the heavy isotope of hydrogen in quantity. Well, this is the way these things go. …So now, are there some more questions about the Manchester era?

Kuhn:

On the question of the induced disintegrations, the first man-made transmutations. Was this easily accepted? It came so hard on the heels of the unraveling of radioactivity.

Loeb:

Everything that Rutherford published —. This is the difference. Einstein was a mystic. He formulated his things in a vague and mystical way. Maybe he hadn’t thought it through well. Certainly he could’ve done his special theory of relativity the way Richtmayer did, in ten pages and did a good job of it, but he didn’t. Rutherford on the other hand always thought in such simple terms, always made his experiments so exact and so precise, there wasn’t any question about it. As I recollect, coming into that laboratory, he was studying the scattering of these light atoms. He told me that, very shortly after I was there or maybe (Mr. K.) told me, he said, “You know we get something very funny in nitrogen. We put an alpha particle in. We know the range of the alpha particle, and we get things way out here. And the range of an alpha particle couldn’t be that, and it must.”

Kuhn:

You’d mentioned that you wanted to say something about Professor Millikan.

Loeb:

I wanted to speak in general about Mach’s idea of heat death. You see, the second law of thermodynamics says that the entropy of the universe tends to a maximum. Consequently, if time is indefinitely long, eventually the universe should run down. Now this has made a lot of people very unhappy. And Millikan in his course in thermodynamics spent a good deal of time thinking about it, talking about this heat death. I was impressed more by Millikan’s fear of the heat death. After all, heat death —. … So it wasn’t very important as far as I was concerned. But these people, with a strong religious feeling, and Millikan with his strong sense of the world in its relation to Millikan and his contributions and all of the things in it. There couldn’t be grayness and death. And this haunted always, and it had some very interesting results later on.

This came to a focus actually when he first did his work on dropping the electroscope into the snow-fed lake up on Mt. Wilson and observed the absorption coefficient of the cosmic rays. Millikan smelled out cosmic rays as important about the same time that Hess did. Well even before that, McClellan in Canada had proven that there was some residual radiation coming from overhead. This was as early as 1913, ‘14 or ‘15. He had made an ice electrometer, taken it out on the middle of the lake in winter, and found that it still fell more rapidly than just the amount due to radioactivity. So cosmic rays — and Millikan was interested. Compton at that time was studying cosmic rays and believed they were particulate. Millikan insisted they were X-rays. And Millikan got this absorption curve. This was not a single exponential, but if you took it it broke up into four exponentials. Incidentally, he made a very funny blunder, in calculating this absorption curve, he had forgotten that not only as you lowered it was there absorption, but also he forgot that there was side radiation which came in, which also diminished and changed. Condon read his first paper on this, and had the temerity to point out that he should have used the (gold) integrals to take account of the side radiation, and that his analysis might be different. Millikan wrote the snottiest letter, “Who was this whipper-snapper Condon…” to question — of course he had used the gold integrals. Well actually he had not used it until Condom called their attention to it. But in any case, they still got four definite absorption curves.

Well, Millikan saw that the energies of these, if you took the energy from the absorption coefficient, indicated that they must be super-energetic. And he assumed that the energy could only come from the creation of iron nuclei in inter-stellar space by a 56 body collision, nucleon collision. And he actually talked about it and published it. And (Joffe), who was here about the time when this came out, we went in to call on Millikan and he was then giving a talk in chapel, and he was lecturing about this, and indicating that the second law of thermodynamic must be reversing itself in inter-stellar space. And Joffe nudged me and said “No, that can’t be right. That can’t be right.” And Franck I think also was appalled by this. He was upset by it. But anyhow, Millikan persisted. And that was the time of the bitter controversy with Compton. And Compton went down into other latitudes and showed that the geo-magnetic effect on cosmic radiation indicated that it was particulate. Well, this is Millikan you see. Now Millikan could not give up the idea. Meanwhile other people talked about it, so Joffe and I got to talking about it. Joffe, said, “Oh, well, of course this is all a matter of statistics. And while the universe may have been going an infinite time already, or a tremendous amount of time, we have not necessarily reached a heat death, because there are statistical fluctuations. We’re in a very improbable state over the eons of time.” Well I wasn’t very happy about this, because this again was as bad as the 56 body impact in inter-stellar space to me, Gilbert Lewis was terribly upset by it also, but he felt the second law must be violated, but he was smart enough to know it wasn’t violated in physics or chemistry or in inter-stellar space or on statistical fluctuations, but he was sure it was violated in the biological field. He was almost a vitalist. I was very friendly with him, and the only time we ever had violent disagreement was when he talked his vitalism and his belief that the second law was being reversed in biological processes. And also he believed in such things as the inheritance of acquired characteristics. He was quite off his base in biology. But again, this continual fear of the heat death.

Kuhn:

I’m just wondering whether you’re really right in attributing this idea to Mach?

Loeb:

Well, at least it was attributed to Mach by Millikan. Millikan got his thermodynamics from Planck. He did not get it from the English. He got it from Planck’s lectures. As a matter of fact, the thermodynamics I teach was taught from the same viewpoint. You see, Planck did something that none of the other theoreticians did. The chemists would develop one brand of thermodynamics, certain people in certain branches of physics another brand, the engineers had their brand. And each approach was entirely different, although Clausius had a general point of view, and Planck carried it further, and it was Planck who brought together the four thermodynamic functions. They’d been invented separately by different people. And showed that you could work the various problems which were posed, such as the e m f of a cell, by combinations of a number of these different functions. He was the one who Formalized the functions, and Millikan taught it this way. So my approach has always been not a single limited approach, but the broader approach from these various angles, and so he may have gotten this from Planck. Because Millikan was not a scholar. Millikan was a doer. And what scholarship he picked up, was largely from his experiences abroad, reading there, and studying and the lectures. And when he put them into his own thinking, all of Millikan’s courses were synthesized this way.

Kuhn:

You’ve mentioned G.N. Lewis several times as we’ve talked. Was he a great influence on the physicists at Berkeley?

Loeb:

G.N. Lewis — well, I think I said a little in my biography. Wheeler tried to build up science. He had Hilgard in botany. He got Osterhaut, he got Taylor, and he got my father. And they began to develop this place scientifically. Then he went off to Germany, and got into difficulties of various types. My father got disgusted. Osterhaut went to Harvard. Taylor went to Pennsylvania. And then he in desperation pulled Gilbert Lewis. Now Gilbert Lewis was a go-getter. (Armon Leuschner) the astronomer, was a close adviser to Wheeler. In fact, he was Wheeler’s right hand man in scientific scholarship. And he backed Lewis. Lewis and (Leuschner) set the stage, E.P. Lewis, the physics chairman, was also very keen to build up the department. Leuschner and Lewis came out and recruited Birge and myself. This was the way they built up the department. Then G.N. Lewis started, was catholic in his interests, and he was interested in relativity. And he brought in this fellow, William H. Williams, who was a teacher at the Naval Academy, an ex-officer, a military academy graduate, but interested in mathematics, and who was able to handle relativity. And he and Tolman, Richard Tolman, and several others, talked relativity. And he was very interested in seeing this develop in the physics department. He was actually completely ignorant of the nuclear atom, and the spectroscopic work. There was then a long period of maybe three years in which he and Birge sort of fenced with each other. Before he got through, Birge converted Gilbert Lewis. Now Gilbert Lewis was very influential in the council of the University, in building up the physics department, and he was on our promotion committee and on a lot of these other things. But he kept his own department and ran his own (baby), but he was responsible for bringing Williams into the physics department. Does that explain the thing?

Kuhn:

What I had most in mind really, when asking that question, because this you had said something about it, was his contact with the physicists and the influence of some of his ideas. I wondered whether his long advocacy of the static atom, for example, had had any effect on the development of physics here?

Loeb:

No, it had not effect at all. As a matter of fact, this is where the battle between Birge and Lewis began, and it ended with his accepting Birge. Now the static atom, I would like to call it. It was the octet theory of valence, from the periodic table, which influenced these people. Lewis saw it and Kossel saw it. They virtually duplicated each other’s efforts, but completely independently. I’m very sure Lewis never saw Kossel’s paper. Lewis went further, however, because Lewis got the hydrogen bond which Kossel missed. Langmuir came into the picture much later. He stole the Lewis concept. Lewis was going around talking about it. He talked all over, and Langmuir took it, and he just called it the Lewis-Langmuir atom. I’ve heard him lecture on it. I mean he deliberately pirated it. Langmuir was a terrific egotist, and I don’t know that he was —. Well, he stole so many things and put his name on so many things. His work on the thermionic — well Childs was the one who got the limitation with thermionic current, but it was Lewis who — Childs had published it two years before, but then it was Lewis who — I mean Langmuir, who had the -– did the publicity. Now he was a great man also. His work is really good work. The great work was the work on surface catalysis and absorption and things of this sort. The Langmuir absorption and a lot of things that Langmuir did were excellent, but a lot of things he did were also wrong, and some things he pirated. And his last work on (rain making) was terrible. That was almost dishonest, because they manipulated the statistics to get —. But he wasn’t entirely responsible, because (Vin Schaffer) was doing the work with him, and there was a lot of wishful thinking in this business. Langmuir was a peculiar person, but he was a success boy, and he did do a terrific job for the General Electric Company. But his pirate-taking of the Lewis atom, it was the Lewis-Kossel atom, the Kossel-Lewis atom. And of course, being committed to the octet theory and so forth, it was easy to account for this with a static atom, and to look at these things.

Kuhn:

You said something before, but mostly after we’d turned the machine off, about the same aspect of J. J. Thomson’s work. Did you ever talk with Thomson, or did Rutherford tell you about his relations with Thomson on this point, of the dynamic versus the static atom?

Loeb:

Well, yes, he said it was embarrassing. He said, “You know, the old boy’s (a little off his ???). Something in this direction. But we get along very well. We just don’t discuss these things.” This was in ‘21. That was I guess the last time I saw Rutherford. You see, then he’d been there since 1919 to ‘24. And that was when I (dined at hall) with him. They got along all right, but this was the only thing that was hard, and Thomson just couldn’t give up the idea. Again, the solution was there, but it wasn’t obvious. It’s the same thing as the dual the wave and the particle dualism and until you got something like the wave equation — you didn’t have that. Does that explain the situation?

[A discussion of Osborne Reynold’s explanation of sinking sands, 1886, is here omitted.]