Edmond Bauer - Session II

Bauer:

… years ago lectured about ultrasonic waves.

Kuhn:

I’m not sure that he may not still have those. I forget what he said. Those were not so relevant from the point of view of the project.

Bauer:

No. But the lectures on quantum statistics were very important.

Kahan:

When was this period?

Bauer:

I don’t remember; I was not in Paris at that time. I was in Strasbourg where I didn’t attend any.

Kuhn:

I wonder whether this may not be the same lectures as the ones in the 20’s that we’re talking about as the interaction of matter and radiation. We’re going to have a microfilm of those, and that, I think, will be a considerable help.

Bauer:

I’m sorry I can’t give you my thesis; I haven’t got it any more.

Kuhn:

But we are aware of its existence, and it is in libraries.

Bauer:

No, it’s in Annales de Physique, I think in 1912.

Kuhn:

Yes. It is always nice to have a copy of published material more easily accessible, but that we can certainly get at. In fact I have been wanting to for some time, and it is at least some index of the busyness and of how little time I have for reading things that I must read that I have just not been able to do it. I’ve had the volume in my hands, but I’ve just not had the time to sit down and read it.

Bauer:

All right. Then what do you want now?

Kuhn:

We have collected a few more questions, but what I would particularly like to start out with —. M. Kahan told me that you had had some further thoughts about the state of French physics, and I hoped you would add those.

Bauer:

Oh, yes. I have two thoughts about what we can call the eclipse of French theory — two things. I am a little sorry to say one of them to an American. I think one of the big reasons is that our Academy, which was very active even at the time of Pasteur, got slowly to be a club of nice old gentlemen who didn’t have much interest in new ideas. I think that’s very important for the evolution of French science. I think quite a new era began when Perrin founded the Recherche Scientifique. What the Comite de la Recherche Scientifique does now ought to be the work of the Academy. It was the work of the Academy in the eighteenth century and even at the beginning of the nineteenth, but at the end —. You see, people like Lavoisier were elected when they were twenty and some years; now people are elected when they are sixty or sixty-five. I think it is a bad organization. Our Academie des Sciences is very conservative; everybody knows our Comptes Rendus ought to be changed, but they don’t have the courage to do it.

Kuhn:

What would you say are the principal changes needed with the Comptes Rendus?

Bauer:

They ought to be divided into mathematics, physics, chemistry, biology, and perhaps even geology and mineralogy. Those big volumes where everything is mixed is not —. And I must say, the members of the Academy ought to be younger because when you give a note to people to be published, people don’t know what it is about. They publish stupid things; they don’t know what it is. I remember once I gave a note to Cotton — Cotton I liked very much; he was a big physicist, but he was old and he didn’t understand what I said. And he made very stupid criticisms.
And the second reason, I think, is very peculiar to our Latin countries. I said that the positivist spirit was against theory, but also the Catholics, like Duhem and Bouasse, were against theories. It was a mixture of positivism and Catholicism. I can read you some pages Duhem made — not Duhem, Duhem was a very good physicist. Bouasse was less known in foreign countries, but he was a very intelligent man and he made about thirty books on physics, a very big collection. And you can find very good information on many problems; now it’s a little old because it was published between 1900 and 1950, something like that. All those books have prefaces, and those prefaces were very well-written; some things were very good, and some things were stupid. He discussed this about theories saying they were all the same, but when the theory of relativity appeared, he didn’t understand it. And when the theory of quanta appeared, he didn’t mention it. I think that’s about all I have to say. Have you some other questions?

Kuhn:

I do have a few other questions. I would like to pursue one point that you made. If someone wants to present a paper to the Academy for the Comptes Rendu, it must be done through a member of the Academy?

Bauer:

Through a member of the Academy, and the member of the Academy is supposed to read it, but there are not enough. There are very few people; there are only six physicists and six chemists. They can’t know everything, and most of the time when somebody of my laboratory gives a note to a man of the Academy, he asks me, “Do you think it’s good?” And if I say, “Yes, I think it’s good,” he doesn’t read it. I could be wrong, you see; he ought to have his own judgment.

Kuhn:

Was that equally true in the 1920’s, that people would not necessarily —?

Bauer:

Oh, yes. I think they were too old even then. I remember when Langevin was elected to the Academy, he told me, “Now, everything will change; you will see, we’ll get a new Academy.” And nothing changed because their force d’inertie is too big. Perrin did something, but outside of the Academy.

Kuhn:

So far as we can find out, these lectures in 1925, 1926 are the first ones that Langevin himself gave on quantum physics, or on a subject related to quantum physics. As nearly as we can now make out, you yourself must be the very first person who lectured in France on this subject.

Bauer:

I think I was the first one, yes.

Kahan:

The first and only. In ‘25.

Bauer:

I lectured in Strasbourg in ‘21; in ‘20 I gave lectures on Lorentz theory. In ‘21 I lectured on quantum theory; I had the book of Sommerfeld, and also I read the papers. I had, I think, two people who heard it. Then when I read on Schrodinger in ‘27 or ‘28; I don’t remember — I had two or three people. It was in ‘27 because I went away from Strasbourg in ‘28 I think. And my colleagues said always, “It’s too adventurous.” And you see, I feel that if I had lived, for instance, in another country —. I was interested in quantum theory, and I think I had some ideas, but I was all by myself, tout a fait isole. I had not the encouragement. The only thing I could do was try to teach it to young people.

Kuhn:

Apparently in Strasbourg the young people were not interested.

Bauer:

No, not very much. I had one who was interested; he is now professor in Strasbourg. That is Nikitine; I think he’s the only one I remember.

Kuhn:

Is that what brought you back to Paris from Strasbourg?

Bauer:

No, what brought me back was that my wife couldn’t support the climate. It was also a little for this reason. In Paris I was nearer —. Langevin at that time was much more interested in those ideas, and I had more people to talk with.

Kahan:

Nous avons eu l’impression de ce que vous avez dit, que vous etes le premier et le seul physicien francais a enseigner, a comprendre la portee de la theorie quantique (et a l’enseigner); et deuxièment, c’est que vraiment que Louis de Broglie etait completement isole; l’impression — les petites contacts qu’il avait eus avec Langevin, ce n’etait pas de l’encouragement, absolutement pas –-

Bauer:

Louis de Broglie had a brother, and his brother was of course a great help for him. His brother, I must say, had —. And I remember Langevin helped Maurice de Broglie when he made his work on the photo-effect of X-rays, what we called at that time secondary emission of electrons by —.

Kuhn:

You say Langevin helped him?

Bauer:

Langevin helped de Broglie. I remember Maurice de Broglie didn’t understand very well the results which he obtained, and Langevin helped him to understand them. I remember I heard one of the discussions between them.

Kahan:

At which time? A quelle epoque?

Bauer:

Je ne peux pas dire. C’est quand [Maurice] de Broglie a publie sa mesure de h par l’effet d’emission secondaire. Il y avait des niveaux d’energie, c’est-a-dire, il fallait des rayons X d’une certaine frequence pour emettre des electrons d’une certaine couche.

Kahan:

Est-ce que vous croyez, M. Bauer, que Maurice de Broglie avait une connaissance des articles, de l’atome de Bohr des avant la guerre de 14?

Bauer:

Ca, je ne peux pas dire. Langevin avait fait faire a son seminaire un expose — je vous l’ai deja dit la derniere fois —. He made a lecture — I don’t know who did it — at his seminar. It was on Einstein’s paper on the interpretation of Sommerfeld’s quantum conditions. It was on some periodicity in space. Perhaps Louis de Broglie did it himself, and that was the beginning of his work. Langevin was interested in quanta, but he lectured more on relativity.

Kuhn:

A small puzzle. The Societe Francaise de Physique used to publish, or to sponsor the publication of, collections of scientific papers… I noticed the other day in a bookstore a very large pair — two volumes — on ionization and charged particles put out in 1905 by Langevin and [H. Abraham]. And I looked at this with great interest because it puzzled me to know: what was the purpose of those? What were they intended to do? A tremendous amount of work went into those. They’re not for history; were they for students?

Bauer:

They were for post-graduate students and also for the physicists. It helped me; I read many papers in there. You can get them I think now.

Kuhn:

In fact I have bought a set, and it will be a great help to me now because it will save me many trips to the library. Still I know of no parallel; the amount of work that those must have taken would be tremendous because everything is translated into French.

Bauer:

Yes. Everything was translated into French.

Kuhn:

In most cases one would expect the physicists and, the graduate students to go to the journals and to read the languages. Now, could one not expect that in France?

Bauer:

I don’t know; I can’t tell you. I think for us it was very convenient.

Kuhn:

They were widely used?

Bauer:

They were widely used, yes. You see, the Societe de Physique had published — that was more of a historical interest — the work of Coulomb, Ampere, Faraday and those people.

Kuhn:

Those volumes I know.

Bauer:

You know those volumes; and it was some kind of continuation of those.

Kuhn:

But those volumes I knew of because that was a series of classic researches published presumably chiefly for their historical interest. But these others were certainly not by any means exclusively classical papers; the field was still very rapidly developing and I was really puzzled to know why the amount of effort would have been expended on these. Does it mean that many people did not read the languages for example?

Bauer:

I think so; I think so. And still people here don’t read —. You see, in America many people don’t read French.

Kuhn:

When I was a student, I would say, anyone going into the sciences was still learning French and German. Now, I think as more people particularly are learning Russian for science, fewer of them are learning French.

Bauer:

Yes. Many people had very great difficulties in reading languages. You see, I can tell another cause of our — that research wasn’t so well represented in France. It was the importance of what we called the Aggregation. I had to do it, and I had the chance to pass it very young. I had to do it because I wanted to be sure that I could earn my living if my research wouldn’t succeed. But in passing the Aggregation we got in the habit of learning things and not of researching. And there was some kind perhaps of a confusion in our minds between research learning and learned learning. And it’s perhaps for this reason that people were very glad to translate some papers and write them in good French to publish them, rather than make their own research. C’est une hypothese, une possibilite. For instance, I had a good friend who began to be a philosopher and went to the Ecole Normale in the class of philosophy and made Aggregation de philosophie. Then he began to learn science, and he was very brilliant as a student, but when he entered in a laboratory — he was taken in the laboratory of crystallography — it was — the laboratory of Mauguin — Mauguin etait seulement assistant. And then he worked for three or four years without knowing what to do. He was very brilliant in learning, but he couldn’t do the research; he was not trained for it. Then he abandoned it and entered an insurance company. And I think that there were so many of those Normaliens who were very brilliant, and when they went into the laboratories, they had no idea — they didn’t know what to do.

Kuhn:

That does help me quite a lot. There are really then, I think, just a couple of other things. We talked after the machine was off last time just very briefly about the monograph you and London had done together in the late 30’s. Leaving out the very recent period — the period since the most recent war — to what extent was the reception of the Copenhagen interpretation, different in France from England, from Germany, from elsewhere? Was there more resistance to Complementarity?

Bauer:

By old people, yes. I know some young ones who told me that this book was helpful for them, but I think the old ones were too accustomed to classical ideas.

Kuhn:

Of course, that, I think, has been true in every country.

Bauer:

In every country?

Kuhn:

Yes. I wondered if there was anything that you thought differentiated the French situation.

Bauer:

I don’t think so. I don’t think so. The only thing is the big influence of Louis de Broglie. In Germany they had Heisenberg, and the influence of Bohr was more direct in Germany. Here the influence of Louis de Broglie was very big, and then perhaps it had a little influence in this sense.

Kuhn:

But Louis de Broglie himself says that after 1928 he accepted it, that he taught it. This is why you know I said leave out the period since the last war, when again I think he has rejected it. But in the interim would his influence between 1928 and ‘45 have been so great?

Bauer:

I can’t tell you; really I can’t tell you.

Kuhn:

I have just one more question. I must say when I started on this project in the beginning of looking at the careers of the Germans; I had had no notion in advance quite how many of them were Jewish. Now, when we talked the other day, again, I was suddenly struck — and this I was equally little prepared for — by the fact that when one spoke of the younger people who had been interested, again how many of them in France had been Jewish.

Bauer:

I first will tell you a story. I was at the Solvay Congress in I think ‘33, something like that, and I was near Darwin. And he told me, “here we are so many English people, so many Germans, so many French people, but the great majority is Jewish.” [Laughter] No, not “the great majority,” but “the Jews are more represented than any country.” That’s what Darwin told me. There was Pauli, Einstein, and Bohr was half Jewish, and Born and all those people.

Kuhn:

I had known this, although I had only I must say gradually become aware of the extent, how far it went for the Germans. But it seemed also to be true to a very great extent in France.

Bauer:

Oh yes. It’s true also. You see, Bloch wrote a very good book on quantum theory, and —

Kahan:

Leon Bloch aussi?

Bauer:

Leon Bloch aussi. Les deux Bloch. Qui encore?

Kuhn:

Solomon.

Bauer:

Solomon, yes Solomon. And Rosenfeld was scholar a l’Ecole Normale Superieure.

Kuhn:

He is half Jew, you know.

Bauer:

He is only half Jew, is that right?

Kuhn:

I’m not sure whether he’s only half; I don’t really know.

Kahan:

He was teaching in Utrecht during the war, you see, so –-

Kuhn:

That ought to be enough to prevent that.

Kahan:

Yes, I suspect, but I’m not sure. I’m not sure.

Kuhn:

There has not been a long tradition of Jews in French science.

Bauer:

No, no.

Kuhn:

I wonder whether in terms of your own experience or impressions, you have any notion as to why this begins to occur at this time, but also I wonder whether there is resistance to there being Jews in France and whether this helps to create the situation

Bauer:

No, I think, during the last 30 years many Jews came from Eastern and Central Europe, and they were people not so saturated by civilization as the ordinary French people and even French Jews, and I think they brought some new ideas; I think that was the reason, the principal reason.

Kuhn:

You think these were people who were mostly emigres?

Bauer:

Not mostly, but many of them. You see, I know some old French Jewish families; they are quite like other people.

Kuhn:

And has this influence itself been resisted?

Bauer:

Not as Jewish, no. Vraiment, sauf sous Petain, on n’a pas souffert de ca. Il y a des gens qui etaient antisemites, comme Darmois, mais il a fini par emettre des theories lui-meme. Il etait anti-theoricien quand il etait jeune.

Kahan:

(Ce n’etait pas) George Darmois?

Bauer:

Non, Eugene, et puis il a fait des theories qui n’ont pas grand valeur, enfin, il a fini par en faire a son tour.

Kahan:

Nous voudrions savoir, M. Bauer, qu’est-ce qui s’est passe a propos de la relation E = mc² entre Langevin et Einstein? La contribution de Langevin, dans quelle mesure etait-elle originale?

Bauer:

Eh bien, je vais vous raconter l’histoire que j’ai vecue moi-meme. I received at that time the Annalen der Physik to make some comptes rendus in the paper Le Radium. And we were very free to make long reports, and it was very interesting for me; I learned very much at that time. Then at the same time Langevin told me — he told us in his lectures before the war of ‘l4 that for the electron we had a mass which was equal to energy divided by — E = mc². And he (???) working on that I think, “It’s a general rule”. And once he told me, “I made the demonstration for radiation and I’m looking for a general proof.” Then I saw I had one paper — it was in 1906 or ‘07 — of Einstein. I didn’t have the first papers of Einstein because I was in Germany when the first papers on relativity appeared, but I had the one where he spoke of this relation. And I told Langevin, “Oh, a German — I didn’t remember his name — has got the same relations that you have.” Then Langevin told me, “Give me the paper.” He read it, and he read then the previous papers, and didn’t publish anything. That’s all that I can tell you, but he was quite independent of Einstein, but I don’t think he had the relativity theory. But he had studied all the cas particulars. Then I must say another thing; some years later he gave a quite general demonstration of this law of thermodynamics, which is very little known because he never published it. It was only published by Francis Perrin dans les Cahiers de Synthese. We have only some — Allard knows more about it than I do myself because he mentioned it, he was in Paris when Langevin exposed it at the College de France. This I can tell you; Langevin had the idea quite at the same time as Einstein, and he knew it was a general law. But I do not think he had the relativity principle directly.

Kuhn:

I gather that you think he did not know the earlier papers either until you gave then to him?

Bauer:

I don’t think so; I don’t think so.

Kahan:

As far as I remember, if I’m not mistaken, the first demonstration of m = e/c² has been given for electromagnetic radiation by Hasenohrl, before Einstein. Langevin was perhaps not aware of this demonstration.

Bauer:

I don’t know; that I cannot tell. Perhaps he knew it, perhaps not. I remember I had to make the comptes rendus of a paper of a student of Planck, von Mosengeil, who had the same relation.

Kahan:

Maybe I’m confused and it wasn’t really Hasenohrl.

Bauer:

I think it was Hasenohrl, but I can’t tell if Langevin knew it or not. He was very keen on that idea and worked very hard, but when he saw Einstein’s paper, he didn’t publish anything more.

Kuhn:

How did he feel about the Einstein papers at first?

Bauer:

Oh, he was enthusiastic.

Kuhn:

From the beginning?

Bauer:

From the beginning. And he gave very soon the lectures on relativity theory. It was Langevin who invited Einstein to come back to Paris to give some lectures in 1920 or something like that.

Kuhn:

Of course, that’s almost sixteen or seventeen years later.

Bauer:

Yes, but he lectured on relativity theory three or four years before 1914. That’s, I think, all that I can tell you.