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Oral History Transcript — Dr. Georg von Hevesy

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Interview with Dr. Georg von Hevesy
By Thomas S. Kuhn, Emilio Gino Segre, and John Heilbron
At Hevesyís Apartment, Stockholm, Sweden
February 4, 1963

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Georg von Hevesy; February 4, 1963

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 l920s. Also prominently mentioned are: Francis William Aston, Karl Auer von Welsbach, Niels Henrik David Bohr, William Henry Bragg, Johannes Broensted, Dirk Coster, Marie Curie, Charles Galton Darwin, Alexandre Dauvillier, Albert Einstein, Roland von Eotvos, Kasimir Fajans, Alexander Fleck, Fritz Haber, Martin Knudsen, Henry Gwyn Jeffreys Moseley, Hantaro Nagaoka, Walther Nernst, Ida Noddack, William Ramsey, Ricci-Curbastro, A. S. Russell, Ernest Rutherford, Erwin Schrodinger, Frederick Soddy, Edward Teller, Thomson, Georges Urbain, M. Volmer; Niels Bohr Institute, and University of Manchester.

Transcript

Session I | Session II

Heilbron:

May I refer first to the earlier problems before you got to Manchester? I am curious whether such a question as the reality of atoms was still a live issue —?

Hevesy:

The reality of atoms?

Heilbron:

Yes, the sort of doubts which Ostwald and others had earlier shed on the question.

Hevesy:

Iíve never heard anyone discuss the reality of atoms. No, the atom and the nucleus were so much in the foreground so that nobody thought about the reality problem.

Heilbron:

This is true even for the beginning of your education, say at Zurich, or —

Hevesy:

I never heard at Manchester anyone who doubted the reality of the atom.

Heilbron:

What about earlier?

Hevesy:

Earlier?

Heilbron:

Say at Zurich or Freiburg, or something.

Hevesy:

Well, at Zurich I really—I donít know. I met Einstein several times, but he didnít discuss the atom. So I had no opportunity to talk to anyone in Zurich who was interested in the reality of the atom. Oh, you mean the very old days—Ostwaldís. Oh, well, itís true. I learned myself from Ostwaldís books; he had very good textbooks, The Laws of Inorganic Chemistry and General and Analytical Chemistry, and he was very inimical I was quite influenced in those days by these ideas of Ostwald, but when I went to Manchester, of course, then they were occupied so much with the atom, the Wilson chamber, and the singular fields and the counting of the alpha particles that I soon had forgotten Ostwaldís ideas.

Heilbron:

What about others with whom you came in contact in the earlier days? Were they similarly influenced by Ostwald?

Hevesy:

Yes. Those who studied from Ostwaldís books were somewhat doubtful about the reality of the atom, while others who studied from books which were defending the reality of the atom were not. Well, it was not a point which we discussed in those days.

Heilbron:

One didnít care about the atomic models in particular?

Hevesy:

No, not so much.

Heilbron:

Were they discussed at all; for instance, was Thomsonís model ever discussed?

Hevesy:

Well, I first heard of Thomsonís model later on when I got my degree. Of course if you believe in Thomsonís model, you must believe the atom; it wonít do otherwise. So, I must say, I had soon forgotten the Ostwald ideas; as soon as I ceased to study from his books. I still have his books here; they were otherwise good chemistry books, but ďinfidel:Ē—he doesnít believe.

Heilbron:

Not only an infidel, but a missionary.

Hevesy:

Yes, yes.

Heilbron:

The reason for your going to Manchester was the question of Haberís idea.

Hevesy:

I went to Manchester to learn electrostatic techniques. You know I intended to work on the catalytic union of nitrogen and hydrogen which was very up-to-date in those days since the discovery that you can unite nitrogen and hydrogen by a catalyzator, and I went to Haber who was a great chemist in Karlsruhe. But he didnít want me to work in that field. He had observed that when liquid sodium-potassium alloys oxidize, electrons are emitted; he thought this to be a great discovery, which it was not, and wished me to study what happens when molten zinc oxidizes. He wanted me to observe whether electrons are emitted as well. But no one had the experience to carry out properly such measurements. Electricity and electrical conductivity of the air was quite a new subject, so I told Haber, ďWell, Iíd better go to learn these methods which are much used in Great Britain, both by Thomson and by Rutherford, and then I shall return to it.Ē So really my aim in going to Rutherford was to learn the methods of measuring conductivity of electricity in gases.

Heilbron:

How did one go about just ďgoingĒ to work with Rutherford? Were there formalities involved?

Hevesy:

Well, I really chose between J. J. Thomson and Rutherford. I happened to meet a man who worked with Rutherford; I think, (Levine) was his name, and another man, (Wimmerling). These two men actually worked with Rutherford and strongly suggested to me not to go to J.J., but to go to Rutherford.

Heilbron:

Why not Thomson?

Hevesy:

He [Levine] thought it better; he thought Rutherford was much more interesting than J. J.

Heilbron:

Nothing more positive?

Hevesy:

Well, it is so that Rutherfordís work seemed more alive, so to speak. So I wrote to Rutherford and asked him for permission to come to work. He answered, ďYes,Ē and then I went to Manchester; that was the story of my going to Manchester.

Heilbron:

But there wasnít much of a problem of just deciding to go to some institution?

Hevesy:

Well, you had to have the permission of course, of the chief of the lab. Passports and such didnít exist in those days, so this was no difficulty at all; permits to stay and such things were non-existent. These great discoveries to (breed) people through these permits are of a later date. So I arrived at Manchester, and there I was.

Heilbron:

Did you begin immediately to undertake what you had intended, or did Rutherford—?

Hevesy:

Actually I had bad luck, you know. On the way I went to Amsterdam to call on an old friend of mine; this was Professor Aten. I stayed with him, and he took me to Hoek van Holland; it was a beautiful night in January; everything looked peaceful and beautiful, but when I arrived in Hoek van Holland, it was the most miserable night. It was the most dreadful passage I ever happened to know before—-seasickness. I wished the boat would have gone down together with me. Then I made a mistake; in England you should always go to London and from London to Manchester. I did it from Harwich directly to Manchester. It took 7 hours; it was winter, and the train cars were unheated so it was quite miserable. I stayed at the (Midland) Hotel of Manchester a few weeks; that was the start of my stay in Manchester.

Then Rutherford wished me to study the solubility of actinium emanations which was a very interesting problem, because there is only three seconds half-life. It was a very good training. I had some lanthanum containing actinium wrapped in paper and put in a glass tube, and sent an air-stream through which carried the emanation, and then a so-called emanation electroscope. Then the emanation electroscope was discharged by the ionization produced by the emanation. If I inserted between the electroscope and my preparation miniature wash bottles, tiny wash bottles, containing various fluids, then these absorbed a part of the emanation and the discharge of the electroscope was reduced. So by taking a number of fluids I studied the reduction of the discharge rate and found that carbon disulfide is the best solute for the emanation—-which is also the best solute for radium emanation.

These sulfur-containing compounds somehow or other absorbed these emanations remarkably. Well, of course, at this date it was necessary to calculate the solubility from these data, and it was Charles Darwin who helped me with these calculations. So we solved the problem and determined the solubility of the actinium emanations.

Heilbron:

Was there any particular reason for Rutherford to be interested inóóó?

Hevesy:

Well, the radium emanation was studied, you know—to some extent thorium also. He wanted to know how the emanations are absorbed. He thought it was a very good problem for someone to learn to carry out radioactive measurements. Just the short life-time, you see, makes it a very fascinating problem. But this was the only job he gave me; later on I chose my own problems. I studied also the chemistry of (???) and measured also the diffusion rate of ions of active radioactive substances. It is a quite interesting phenomenon that if you measure ionic mobility of barium ion and potassium ion, itís about the same. The barium ion has two charges, so actually it should move twice as rapidly, but it does not. And the explanation is that due to the two charges, the barium ion is more strongly hydrated than the potassium ion. This compensates the two charges: the barium ion getting larger moves slower.

But if that is SO then you would expect, by measuring instead of the ionic nobility in an electric field, the diffusion rate, that barium should, having two charges, move half as rapidly as potassium. I availed myself of this method determining the diffusion rate of radioactive substances and concluding from the data how many charges they carried. Now, the anion has also a role, but you can eliminate it by letting it diffuse, not in water, but in diluted hydrochloric acid where in a great excess of chloride ions the role of chloride ions becomes minimal, and you get actually a diffusion of the cation, uninfluenced. That was quite a job which I carried out; it was what I was doing mainly while at Manchester. Then I made trials to separate Radium D from lead. Rutherford wanted to study the properties of radiation, of Radium D, which emits very soft beta rays, and he needed a strong preparation. He had a lot of radium lead given to him by (???). The radium lead was embedded in large amounts of common lead, and therefore was of no use. He was very anxious to get rid of the common lead, so I worked very hard, and I thought that it should be possible, but it was not. Sometimes it looked as though Iíd succeeded, but I found out it was Radium E //which is not radium at all but rather a// bismuth isotope which actually separated. The separation of bismuth from lead is not so difficult, but getting Radium D from it wouldnít work. Then I got the idea of labeling lead by adding pure Radium D.

Heilbron:

What did Rutherford think of the result? Did he think that your chemistry just wasnít sufficiently good?

Hevesy:

Well, his was also not too good; Rutherford was not too good at all as a chemist.

Heilbron:

So he didnít consider the results of any interest then?

Hevesy:

No, I donít know whether he did, but he invited Boltwood, who was a very good chemist from Yale to separate ionium from thorium atoms. He failed also, so I was not the only one. But I donít think he had so much interest in the work; he was content to settle for the Radium D which we get from emanation tubes. I was interested in the problem and thought it should be possible to take just a few milligrams of lead salt and add pure Radium D and use it as a tracer. The place where most Radium D work was being done was the Vienna Institute. So I went to Vienna and started there to work out the result with my late friend Paneth. So we carried it out; we worked very hard and were quite successful in our work. We solved a number of problems which this labor had led to. That was in January, just fifty years ago; it was the first week of January, 1913, and then in April (I returned to) Manchester. So I worked only 3 months in Vienna, but quite successfully and very hard.

Heilbron:

Did Rutherford make any effort to explain to himself radio-activity and so on, on the basis of his model before Bohr arrived? Were those sort of separate things to him?

Hevesy:

No. Oh, he thought always that a primary process is the emission of alpha particles. That was a very early conviction of his—he always felt that. So that the emission of an alpha particle starts the whole business; that was his idea.

Heilbron:

And the betas had to be left to take care of themselves, is that it?

Hevesy:

Yes. Then you have the reorganization of the atom in successive steps; he called it also successive transformation then.

Heilbron:

But Bohr was quite clear from the beginning that that was wrong?

Hevesy:

Yes. I mean Bohr was quite clear about that. Although undoubtedly he took into account that it was wrong because the uranium series and the thorium series actually start by making alpha particles. That is the first step.

Heilbron:

And on the question of the origin of the betas?

Hevesy:

The origin of betas, yes. Of course Rutherford didnít know, but Bohr was quite clear about the fact that betas connected to atoms in transformation are bound to come from the nucleus, while the others come from the outer shell. Bohr was quite clear about it from the beginning.

Heilbron:

Others at Manchester felt Bohr was right?

Hevesy:

They were all occupied with their own problems. The only man who really was interested was Charles Darwin; he discussed such problems—Moseley also to some extent, but the others were not so much interested in such problems. They were more interested in their own special problems.

Heilbron:

You referred, I think, to a conversation with Rutherford in the presence of Bohr where you asked him about—-

Hevesy:

Yes, yes, yes. I asked Rutherford where the beta particles came from, and Rutherford answered, ďAsk Bohr.Ē It was a Sunday afternoon; we were at his house. So he thought Bohr knew much better than he, very wisely.

Heilbron:

Did Rutherford believe Bohr at that point?

Hevesy:

Oh, yes. Otherwise he wouldnít have said, ďAsk Bohr,Ē if he hadnít believed that Bohr had an answer.

Heilbron:

Well, how interested was Rutherford at all in the success of his model? It seems, to read his own presentations of it, at least in print, that he was not at all interested in pushing it.

Hevesy:

No. I mean, Rutherford was an experimenter; he carried out experiments and followed the conclusions of his experiments, but to go further and to speculate very much—-that was not his line. He found the nucleus when he speculated on one point. He spoke, already in Manchester about the neutron. He said that a material must exist in the atomic nucleus with an atom charge of zero which he already called the neutron. And he added, ďIt will be exceedingly difficult to find it because it will pass everywhere and you canít catch it.Ē He underestimated actually the ionization which the neutron produces. It produces very little ionization but it does produce some.

Heilbron:

But you say Rutherford discovered the nucleus, but one reads the papers, and, one is curious whether Rutherford discovered the positive nucleus. That is, the original paper has the nucleus either plus or minus, and so forth. One has the option of the model as it came out or the inverse as it is there presented with, a negative central charge and a positive spherical shell of electricity, and I was wondering how much the development of the model has to do with Bohr?

Hevesy:

Yes, I think that Rutherford himself, therefore, believed that it was a positive charge in the center of the atom. It is very difficult otherwise to explain the deflection, you know. How do you explain that the alpha particle is scattered 180 degrees if you donít assume something in the atom which scatters it.

Heilbron:

But it can be bent either within or without the focus; the mathematics are the same whether the nucleus is positively or negatively charged.

Hevesy:

Oh, the negatively charged nucleus wonít scatter such a positive particle.

Heilbron:

Youíll have a cometary orbit; it would be just as a comet.

Hevesy:

But itís not this straight-forward; itís an excuse, you see, not a straight forward explanation. So when Rutherford found it, I donít think that he doubted that in the center of the atom is a positive charge.

Heilbron:

But he says it might be positive or negative in his paper announcing the experiments in 1911.

Hevesy:

Well, he wanted perhaps to express himself very carefully. But I always got the impression that he actually, personally believed in a positive charge. Of course Bohr strongly contributed then to this conviction. If I remember well, the denomination ďnucleusĒ really originates from Bohr; Iím not absolutely sure, but I think so.

Heilbron:

How much was the problem of the radiation effect and the stability of the atom questioned at the time? Were discussions in Manchester centered on the problem of the radiation from such an atom and its lack of stability?

Hevesy:

I donít think so really that Rutherford speculated very much on this point, you know.

Heilbron:

But Bohr.

Hevesy:

Bohr. Of course I agree that was the starting point for Bohrís consideration. That was the starting point and he found then the explanation. That was perhaps the greatest achievement of Bohr.

Heilbron:

It was perhaps a question that bothered you too, the stability of the lighter atoms, since I recently read a letter of yours to that effect. But you seem to be content with situation for the heavier atoms. Do you recall that?

Hevesy:

No, I canít recall it in fact. I canít recall it. Did I write Bohr?

Heilbron:

Let me show you. [Locates the letter.]

Hevesy:

I canít recall it.

Heilbron:

It may interest you—this—Iím sorry this copy of the letter is so bad. Itís in January of 1913.

Hevesy:

Ah, itís written in German. [Reads aloud from the letter of 29 January 1913. Here Hevesy says that he also has been thinking a great deal about the stability of Rutherfordís atom and has come to the conclusion that a single, light, neutral atom is incapable of existing alone. Radiation is not mentioned. See microfilm of Bohr correspondence for photograph of the letter.]

Heilbron:

Yes, evidently there were quite some talks about the point, I should say.

Hevesy:

Yes, yes. But I donít think that I discussed this point with other people. I wrote this from Vienna, you know. And who was there who might have been interested? Stefan Meyer was certainly not; my friend Paneth was, but otherwise there was no one.

Heilbron:

Well, he wrote a letter to you in answer to that which is most interesting. I donít see how it could have at all comforted you in this problem; itís very difficult to understand without knowing all the Bohr theory that came since. I was wondering if you recalled his response, what you had thought of it.

Hevesy:

No, but I must have his letter. You know this was early in Ď13, and his paper came very shortly after that, you know. And when I read, of course, his paper, then the answer was given in the paper, how it comes that an electron doesnít fall into the nucleus.

Heilbron:

Were the questions of the spectral lines of much importance? Did people at Manchester care at all about the optical spectra?

Hevesy:

Yes, yes. The great excitement was, you know, Fowlerís work. How was that? Fowler denied that helium has two electrons-was it not that? Or was it the opposite with hydrogen? It was a discussion between the Ďopticianí Fowler, an experimental physicist, and Bohr, Fowler doubted the correctness in Bohrís theory.

Heilbron:

This was before his publication?

Hevesy:

The earlier publications. He felt that Bohrís data and some spectral measurements on hydrogen or helium donít fit, and then Bohr was showing that what he considered to be helium spectra was actually hydrogen spectra. Evans, the spectroscopist at Manchester, was to test this point by preparing pure hydrogen and very pure helium; he found out Bohr was right.

Heilbron:

Oh, yes. That was after the first paper.

Hevesy:

Yes. So that was a great spectroscopic excitement. But at a very early date Rossi and Russell at Manchester found that ionium and thorium had the same spectrum. That was a very interesting finding. They wrote a letter to Nature and Arthur Schuster answered that it was impossible that two different substances have the same spectrum. Of course, both were right; if you go, of course, to very exact measurements you find differences, but in the usual accuracy of spectral measurements you wonít find any. But it was a very singular point, you know. Thorium and ionium had nothing to do with these—. This letter I must have written early in 1913; it was just fifty years ago.

Heilbron:

In January, I think.

Hevesy:

Yes, yes. Shortly thereafter I came to Vienna.

Heilbron:

In Manchester the interest was somewhat greater in the X-ray spectra, was it?

Hevesy:

In Manchester, yes. There was very great interest in the counting of alpha particles; there was a great progress. You know Rutherford and Geiger using the galvanometer counted alpha particles accelerated according to Townsendís principle by putting a few thousand volts; you get a kick in the galvanometer. That was great progress and a great excitement. That was one point, and then there were different studies on alpha particles and beta particles and Moseleyís work, of course.

Heilbron:

How did Moseley happen to be so advanced at so young an age?

Hevesy:

Well, Moseley was a very brilliant man. He was a brilliant experimenter, and he went to Leeds where Bragg was then—the old Bragg. Old Bragg really initiated this idea of spectroscopy.

Heilbron:

Of the X-ray spectroscopy, yes.

Hevesy:

X-ray spectroscopy. But then Moseley got the idea, ďWell, I will go through the whole periodic system and see how tellurium and iodine and potassium and argon, etc., fit in the system.Ē And it was a really marvelous perception to work out the method to fix the crystal and put all these elements in small sledges in a vacuum and work from outside with strings, you know. He just moved one element up after the other. I went to see him in the Chemistry Department to look for a crystal. He should have a crystal, and I remember—just things you remember sometimes very clearly—that there was a very nice steward, Mr. (Edwards). He showed us a potassium ferrocyanide crystal, and said, ďItís a beautiful crystal.Ē Moseley said, ďThatís good, Iíll take that crystal.Ē And all the work was with potassium ferrocyanide, and it took him a comparatively short time. He just went one element after the other.

Heilbron:

So far as you remember the idea of measuring the K-lines of each element was Moseleyís?

Hevesy:

Moseleyís. But you had Barklaís work on characteristic radiation contributing a great advance, and Braggís work that it should be possible to make such a spectroscopy. And Bragg Jr. in his historical review claims also the idea of X-ray spectroscopy goes back to his father. This was just the idea, but carrying out the X-ray spectroscopy was a marvelous thing which Moseley did.

Heilbron:

He was able at that point to determine his own research with no problem from Rutherford.

Hevesy:

No, no. Not from Rutherford, no, no. This was far away from Rutherfordís interests, you know, so this was entirely independent.

Heilbron:

One was fairly well able to determine oneís own direction?

Hevesy:

Yes, yes, one did this, I worked on my own problems; he never interfered with this. He had enough to do; he was pleased when people found their own problems. I was very interested in Moseleyís work, and he left Manchester then in Ď14 and went to Oxford. I intended to work with him in Oxford, and we had an appointment that I should come in the first of August, Ď14, to Oxford and bring with me rare earth samples. He wanted to study the X-ray spectrum for the rare-earth elements, elements 69, 70, 71, and so on. There was in Austria a man Auer von Welsbach who was the latest authority in this field and the best, the only, man in the pure rare-earths. Another man who was not so poor, but still had rare earth samples was Urbain in Paris. In the meantime, Urbain sent samples to Moseley, so Moseley wrote that it was not necessary that I bring our samples when I came to Oxford. I was already in Holland on the way to Oxford when the war broke out. Thatís why I couldnít go to England, but my intention was actually to assist Moseley—-to work with him on rare-earths, with X-ray spectroscopy.

Heilbron:

I ran across a very interesting letter from Moseley to Rutherford in which Moseley, referring to the Bohr atom, says, ďOf the three atomic models now going which try to build atoms with e, h, and m, I think Bohrís is far and away the best,Ē or something like that. Do you have any idea what the other two might have been?

Hevesy:

The one was certainly J. J. Thomsonís, J. J. Thomson had this atomic model. The second was Bohrís; what the third was, I donít know.

Heilbron:

Perhaps it was Nicholsonís.

Hevesy:

It may be; it may be.

Heilbron:

I have been curious about that. There is one other thing that was said in the last talk—no, I guess it was another letter that I found in Eveís Biography of Rutherford. This letter you wrote Rutherford, I think from Vienna after you had talked to Einstein, and Einstein made some statement that he had thought of something similar, but hadnít the courage to develop it, or hadnít the push to go further, or something of that nature. Do you recall in greater detail any of the circumstances?

Hevesy:

I only recall that I talked to Einstein in Pasadena once. It was later—in Ď31, and Einstein told me that he didnít agree with Bohrís views which is to us already a very different chapter. It was already probability consideration.

Heilbron:

But I think this was in 1913.

Hevesy:

In Ď13. I saw a lot of Einstein when I was in Zurich, but it was 1929 then.

Heilbron:

This was at a Congress.

Hevesy:

Oh, yes. It was a Congress of German Naturalists in í13; it may be that Einstein was there. It was a Vienna meeting of German Naturalists—a big meeting. It may be, but I canít remember. Do you want to look at Eveís book?

Heilbron:

Do you have it easily at hand? This would be quite interesting.

Hevesy:

Yes, I can find it at once, I wrote about Thomsonís—yes, here, but I donít see anything about Einstein here. Oh, yes here it is. [Reads from p. 223 of book]: ďSoon Einstein, among different topics, began to speak on Bohrís theory. He told that he had once had similar ideas but didnít dare to publish them. Should Bohrís theory be right, it is of the greatest importance. When I told him about Fowlerís spectrum experiments the big eyes of Einstein looked still bigger as he told me, ĎThen it is one of the greatest discoveries.íĒ

Heilbron:

Well, I was hoping that perhaps you recalled some more details of that conversation.

Hevesy:

Now, I can recall that Einstein was impressed by—. After quantum theory was more or less initiated he was close to the idea of applying in some way quantum theory to explain the atom—really similar ideas. But as he says, he didnít dare to publish it.

Heilbron:

Itís interesting to consider Einstein not daring to publish ideas.

Hevesy:

Yes, itís too fantasticÖHow was it—was it hydrogen or helium?

Heilbron:

Well, the question I know of is that Bohr attributed some of the lines that Fowler thought were hydrogen to helium; that was the difficulty.

Hevesy:

Yes, yes; thatís it.

Heilbron:

And, of course, they come out very close to the same, if youíll allow the Balmer denominator to be half integral.

Hevesy:

Yes, yes, yes. So this was really the point which still looked as though it didnít match with Bohrís views, and when he heard that even this matches then Einsteinís big eyes became still bigger, wondering at this very great discovery. I remember I was there when Einstein gave his first lecture in Zurich on e/m—-Buchererís. He was fairly unknown; he was associate professor in the University of Zurich, and then Nernst, who was a very famous man in those days, was interested especially in the heat of gases and wanted to apply quantum theory to the specific heat ideas. And he came to Zurich to consult Einstein on this point. That made Einstein famous, that the great Nernst came to Zurich to talk to him. He was the bright fellow; is it not amusing?

Heilbron:

It is amusing Do you recall anything about those conversations, or were they justó

Hevesy:

No, no, no. I wasnít present when he met Einstein, but Nernst made good use of quantum theory in his specific heat considerations How far it emanates from Einstein or not I donít dare to say; I was not present at any discussion. For a few days he just came to Zurich; he was a very great man in those days, Einstein.

Heilbron:

After Nernst had made him famous.

Hevesy:

Then he had a Nernst lamp; I donít know whether you have ever heard about this; do you know? A lamp; an electric bulb, a semi-conductor bulb. It was advertised as the greatest discovery. He got a million marks from the German electrical firm, AEG. A million marks was a lot of money in those days before the First World War. It was as much as 10 million now you know, but it practically didnít work. Well, it worked its use was very elaborate. The firm lost a lot of money, and Nernst made a lot of money. So that made him also very famous that he could even construct such excellent lampsÖ

Heilbron:

Well, we would be delighted for any further recollections you may have.

Hevesy:

What can I tell you which would interest you? You know, it should interest you. Bohr told. you certainly that when he sent his first paper to Rutherford, Rutherford didnít like it; it was too long.

Heilbron:

Did he have any objections besides the length, do you remember?

Hevesy:

The length and language. Language of course could be amended, but it was much too long. He should cut it to a fourth, or something like that.

Heilbron:

Do you remember any of the things that Rutherford thought were expendable?

Hevesy:

I canít really say what was expendable, but altogether, I mean—- Bohr repeated of course his line of thought, you know, to exclude some objections. He tried already in the paper to exclude objections towards his argument, and this is what Rutherford really wanted to eliminate, saying that it is no good beforehand to fight your adversaries; state your fact and let it later if necessaryÖ But soon after, Bohr sent him his second part; it was still longer and filled Rutherford with despair. They had a long correspondence, and then Bohr thought, ďWell, I must go personally to Manchester.Ē He took the boat, and he went to England, went to Manchester, and was sitting all night with Rutherford. Finally he convinced Rutherford the paper should be published in the original form. Rutherford didnít like it. He told Bohr, ďI didnít know that you were so pig-headed.Ē But actually it was printed in the original form.

Heilbron:

What happened to persuade Rutherford finally, do you know? Did he just want to go to bed and gave up arguing or—-

Hevesy:

He just gave up. (It was morning.)

Heilbron:

But if Rutherford hadnít agreed to it in that form, could Bohr not have communicated it directly to the Phil. Mag.?

Hevesy:

I donít know. The Phil. Mag. was very critical, you know, especially of theoretical papers—they didnít like them. It would be very difficult to tell; it may be that it would have worked; also it could be that the Phil. editor would say, ďYou know thatís much too long.Ē NŲw itís very different; in those days printing was not so expensive, you know, so the expense probably didnít play such a great role as it does today.

Heilbron:

There are some articles as long as Bohrís, even longer, in that same volume of Phil. Mag. on the same kind of subject.

Hevesy:

You know, of course, after these papers came out and Bohr became a world famous man, he wouldnít have any difficulties any more communicating.

Heilbron:

No, theyíd be delighted.

Hevesy:

But with the first paper I donít know if they would have printed it unchanged and unshortened. Today, you know, of course everything is the expense. I just sent a paper of 40 pages and a great number of figures to a British journal, and they have answered me that it is so expensive; they would like me to cut it in halfÖ But in those days this side had no importance. 525 And even in those days of the Phil. Mag. it was expensive; it wasnít the expense so much as they didnít like to print articles so long that the reader would not touch them. That was actually the main consideration in those days. But Bohr usually sent papers, also later, to Rutherford—through Rutherford also. It was politeness toward him.

Heilbron:

Well, of course, it would also guarantee it being read if it were communicated by Rutherford..

Hevesy:

Yes, yes.

Heilbron:

Well, do you recall reactions other than Einsteinís to Bohrís theories?

Hevesy:

I mean, some people like Nicholson, you know, were very critical. They didnít like it, but most people were very much interested, even if they didnít understand it really. They had the impression, that is a great step forward. Well, in this manuscript I gave you I recall a letter to Nature which was also sent via Rutherford. Rutherford forwarded it later to Nature.

Heilbron:

But Nature would print almost anything?

Hevesy:

Oh, they would have printed itÖ Nature was a very good periodical; now, it is too voluminous, but itís still a very good periodical. All those letters which are printed today; you could read a week or more on one copy if you wanted to read every single page. Of course, itís changed since the old days. (Gregory), who was the editor for many years, was a brilliant editor. Itís not easy to compose such a copy of Nature. Shall I bring those letters?

Session I | Session II