Oral History Transcript — Dr. Merle Tuve
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Merle Tuve; January 13, 1982
ABSTRACT: Early youth in Canton, South Dakota; teenage interest with E. O. Lawrence in radios and electricity; origins of physics interest at Augustana Academy, Canton; college years at the University of Minnesota until 1923; graduate work at Princeton University and at Johns Hopkins University; Ph.D. at Hopkins in 1926 for collaboration with Gregory Breit studying ionosphere with radio waves; position at Carnegie Institution’s Department of Terrestrial Magnetism (DTM); nuclear physics work with Odd Dahl, L. R. Hafstad, and others using Tesla coils in 1920s and Van de Graaff generators in 1930s; head of proximity fuse work and first director of the Johns Hopkins Applied Physics Laboratory during World War II; return to DTM, becoming director 1946-1966; DTM research during directorship in seismology, biophysics, and radio astronomy.
Session I | Session II
Tuve:Perhaps you will tell me a little about what your plan is? I am somewhat staggered to be the subject of a Ph.D. thesis. [laughs] Especially because I am not dead yet.
Cornell:I come to it because of my interest in nuclear physics, especially experimental nuclear physics in this country. From the work I have done it is clear to me that the change in experimental physics over the last hundred years is remarkable.
Cornell:And I think nuclear physics provides an opportunity to understand those changes in a particularly clear-cut way.
Tuve:Where was your undergraduate background?
Cornell:I went to a small school in Memphis, Tennessee. Southwestern at Memphis [now Rhodes College].
Tuve:I've heard of it.
Cornell:My professor there — I studied physics there — was a Hopkins graduate, and so I heard a lot about Hopkins.
Tuve:What was his name?
Cornell:Jack [J. H.] Taylor.
Tuve:You don't know roughly what epoch he is?
Cornell:He did his dissertation at Hopkins in the mid-fifties .
Tuve:I had lost contact by that time with individual members. So how did you get the idea of taking this as a thesis subject?
Cornell:The first day I was at Hopkins I was talking with my advisor about what I might do and he pulled out a book by Nuel Pharr Davis, LAWRENCE AND OPPENHEIMER. I read that and it looked interesting.
Tuve:As I remember that book, it's a little too bad to emphasize the stresses between them.
Cornell:Yes, I think there are some difficulties in the book.
Tuve:It wasn't a graceful performance.
Cornell:So I started looking at [E. O.] Lawrence's work with the cyclotron and was having some difficulties understanding exactly how he got started building equipment.
Tuve:[laughs] We were old pals from ham radio days — "amateur radio" it was called then — back in 1914 and 1915. Ernie Lawrence got started with electronics in my dad's basement — in our basement. We inherited a bunch of electronics equipment, so-called, from the Boy Scouts. My father [A. G. Tuve] was scoutmaster. The scouts got tired of it, and so it was left in our basement. Ernie and I have a long history together. He went to the University of South Dakota. Then I arranged for him to get a fellowship at the University of Minnesota where I graduated, and we were together again. Then he went off to Yale and I went off to Princeton — later Hopkins. When Ernie took a job as assistant professor at the University of California he paid me a couple visits at our Carnegie Lab and I told him — he was playing around with gyroscopes, high-speed spinning things — and I said he ought to pick out a subject with obvious expansion possibilities and not monkey around with this diddle here and that diddle there. I lambasted him like a good old friend and then told him: "The kind of thing we're doing here may be hopeless — may be a heck of a long road — but it is worth doing, it's obvious." I'm sure he took it to heart. He was playing around with different things until the afternoon that he and [M. S.] Livingston figured out the cyclotron. Well, I'll let you go ahead with your quizzing.
Cornell:What interests me about your work in the 1920s is that it started so early — your interest in a program of nuclear studies.
Actually, I took my Ph.D. on radio echoes from the upper atmosphere. Afterwards I understood from my thesis advisor, Joseph Ames, that they would accept this for a thesis. The work was done in the summer of 1925, and by November it was pretty well clear where we were at. Professor Ames told me to write it up and get a decent paper out of it. I meanwhile was paying occasional visits down to Washington. Dr. [A. J.] Fleming, the acting director of the Department of Terrestrial Magnetism asked me to stay on and do the radio work. But I said no, I was planning on getting a fellowship to go to Cambridge. I was just about ready to apply for a National Research Council Fellowship at that time. This was December 1925 and January 1926. Sometime in early January Fleming asked me if I would take a job and I said no, I was applying for this fellowship. And he says, "Well, can you finish this in one year?" I said I wanted the fellowship to try to put high voltages — like a million volts — on a vacuum tube, in order to produce high speed protons, because obviously the laws of electricity and magnetism break down in the nucleus. We don't know how the nucleus manages to hold thirty or twenty or ten positive charges together and not blow up.
So it's clear there's a change in the laws of attraction someplace. I said I wanted to measure that, probably by Rutherford's billiard ball scattering, scattering of alpha particles on helium. "We'll use the same technique, with protons on hydrogen." And I said maybe after a while there will be disintegrations. Rutherford had produced disintegrations back in 1919, so that wasn't news exactly. That was all included in the original tenure of a job for me. He said, "Can you finish it in one year?" And I said, "No." [laughs] "But maybe we'd get it started." He said, "Well, why don't you come here and do it?" I said, "You'd do high voltage physics in the Department of Terrestrial Magnetism?" And he said: "Yes. You can't make a new department every time somebody has an idea. You have to blanket it in under the existing administrative framework." I was flabbergasted. So I was practically on the equivalent of a Research Council Fellowship for years. I felt that independent, that free. And he treated it the same way.
Cornell:So Fleming was supportive of your work?
Tuve:Yes, in small ways. But mainly by paying a salary and letting us be free. We didn't have much equipment money. We had a two thousand dollar stake to start with. That was on the radio work. So we had a little money for that — for photographic materials and so on — but not much for equipment, except what you make yourself.
Cornell:Did your radio work compete with your interest in the high voltage work?
Tuve:Well, the agreement was that I would do some radio work in order to earn the right to do nuclear physics. So, yes, I continued that from 1926 through 1930. The Bureau of Standards had a radio section and Dr. [J. H.] Dellinger, the head of the section there, was interested in fading measurements. I was impatient with that sort of monkey business. We had demonstrated that fading didn't mean anything because you'd have to know whether you were getting more than one return welded together or a pure return. So I said to Fleming: "We'll never get the Bureau of Standards to do anything on this unless we step down. Otherwise anyplace we sit we're the captains of the nest because we were there first. So I think the thing to do is to tell Dellinger that if he'll go after it in a good, big way we'll step aside." This was about 1930. Dellinger took Fleming up on that, put a line item in the budget of — oh, it was more than half a million dollars, $700,000 I think, which was a lot of money in 1929 — or 1930 (it was after the crash). He started, but in 1931 or 1932 Congress cut back. Dellinger had hired Lloyd Berkner. He was also from my alma mater, Minnesota — a Minnesota engineer. When I learned that Berkner might be pried away from the job, I said the only way to save this situation is to get somebody who works on it full time. I recommended to Fleming right off, "Hire Berkner." And he did — in one day. That's how we both expanded that program and reduced the amount of pressure on the high voltage work. So we went right ahead with only that.
Cornell:Was the close relationship between the DTM and the Bureau of Standards in this case a remarkable one?
Tuve:No. Not at all. It was a standard practice. We went back and forth. Cryogenics, and — oh, all kinds of measurements, gravity meters, electric things. Of course, at the Bureau they had some high voltage test equipment. But we never got the opportunity — didn't try really — to put one of our tubes on their high voltage.
Cornell:You had several people helping you with the nuclear work. Odd Dahl.
Tuve:Breit was the leader of it. Breit fostered it. He was the one that asked Fleming to have me come down in the first place when we originally suggested this echo thing, which was an idea floating around at the University of Minnesota. Then Gregory was a mathematical physicist on the staff there, and he requested me as his assistant. So there is no doubt about it, Breit was the man who fostered and started it. I came in under that blanket. Dahl came next. Dahl was [H. U.] Sverdrup's assistant on the cruise of the Maud. This was a non-magnetic ship that tried to sail the Chukchi Sea to the west and got stuck in the ice for three years. He made electrometers out of his meerschaum pipes and amber fittings and all kinds of things. Dahl was an aviator. He was the first aviator to attempt to fly [R. E. G.] Amundsen over the pole. But they fortunately crashed in trying to take off with such a heavy load of gasoline, so he was stuck on the ship. He came, I would say, in early 1927. And then [L. R.] Hafstad came in 1928, probably. He was a student at the University of Minnesota that I had kind of fostered. He was a telephone technician, and I ran into him because after I graduated in electrical engineering I worked for a while for the telephone company. This smart chap struck me. I persuaded him to go to college — to engineering school — instead of just being a technician. When he had finished I telephoned him and said, would he be interested in a job in Washington. And so he came. So it was Breit, myself, Hafstad, and Dahl until about 1935, when [N. P.] Heydenberg joined us — maybe it was 1934.
Cornell:Did Dahl and Hafstad come to work with the nuclear program or did they come to work with the radio program — or both?
Tuve:Breit was hired as a mathematical physicist. The older director of the department [L. A. Bauer] had had the notion that somehow or other in relativity there might be the explanation of the earth's magnetic field. So that was the general problem he asked Breit to examine — if there was any way that by relativity you could understand the magnetic field. Breit, when he discovered that that was Bauer's principle aim, expostulated. He wouldn't have anything to do with it. [laughs] So he just undertook to do anything that was intelligent relating to the Department's interests. The obvious thing was the conducting layer which Balfour Stewart and others had postulated way back in the 1880s. It had never really been verified as to its existence or its height or its characteristics. We knew each other from Minnesota. He came as a young associate professor, just arrived in the summertime that I was leaving. I took my Master of Arts degree in June 1923. He came in July. I was just finishing up some research on positive ions. We'd go run around the track in the afternoons, and so on. So I was acquainted with Gregory from Minnesota. He knew I had worked on very short waves –- 80 cm — and he wanted to have a parabola send 80 cm waves up to the sky and hope to receive them again in Baltimore, and he asked me to do that. Well, that scared me because I had a hard time making reliable detection of 80 cm waves just across the big laboratory room, to say nothing about all the way to the sky and back. So at a meeting that Dr. Fleming held — this was in October 1924 — he had a meeting with some people on whether he should build this parabolic dish, which was estimated at two thousand dollars. I guess you may have heard of this story before.
They called on me to speak for the receiving end in Baltimore, and I said: "Well I very much believe you ought to support this kind of an experiment. But I'm not at all sure that we can get reflections from the sky intense enough to be able to receive them." So I said: "I recommend that you give the two thousand dollars to Breit. Make it available to Breit. But leave things open as to whether he does it with a parabola or some other way." And I said, "For example, W. F. G. Swann at Minnesota has been trying for a few months to see if he could get echoes by interrupting a transmitter." He put a commutator on a transmitter. It went on –- off –- on –- off –- on — off. But it was hopelessly noisy. It just made a great buzz in his receiver. So it was inadequate technique there. But the idea of it had floated around. It was pretty obvious — sonar, and so on. I suggested that we might want to try that before we spent a lot on a parabola. Then we went on from there. We tried it with the help of a Navy transmitter at NRL [Naval Research Laboratory], and got the echoes late in June 1925.
Then we followed them up in July and August and September. In September we got a chance to run the transmitter in the evening. Up 'til then we'd had only an hour in the afternoon that we could have this Navy transmitter, which was a 20 kilowatt unit. We brought the keyer down, which was simply a chopper that gave you a short on period at 500 cycles. We had got the echoes, but we couldn't be sure where they were coming from. We tried with various antennas, and it was clear they were coming at an angle to the earth. They weren't coming vertically. But we couldn't be sure because the virtual height that we got was 75 kilometers. Well, that's approximately the same distance to the Blue Ridge Mountains, and they stayed there all the time. So we weren't sure. But when we had some evening transmissions, we saw them rise on up. We knew the Blue Ridge wasn't moving [laughs] so that's where it was from.
So that's the first of pulse radio. We went on a year from there at Breit's suggestion with a multivibrator to make a short pulse and a long dead space. Dahl and I rigged that up. One of the interesting experiments with that was the echo-interference method, we called it, where we made a pulse but we leaked a small amount of the RF from the transmitter. This was the transmitter and receiver both down at NRL, so they were only a hundred feet apart. We leaked some of the crystal signal continuously to the receiver and put it at approximately half deflection of our receiving unit, of our galvanometer. When it came phased with the crystal the peaks went up, but when it phased against — out of phase 180 degrees — it went down. We'd see it going up and down and up and down, measuring one wavelength at a time. These were, I think, 40 meters. Maybe they were 80 meters. We had those two wavelengths. You'll have to excuse Parkinson's, here. It's gotten kind of bad in the last year [laughs]. I can't hardly sign a check anymore.
Cornell:Had Dahl come specifically to help you with the radio work?
Tuve:Dahl came as Breit's assistant. Fleming just wanted a — I don't know just how it came about. Sverdrup was an oceanographer with Scripps, and he had been associated with Fleming in various things for some years. I think Sverdrup simply spoke highly of Dahl, and Fleming said: "We'll take him on. We're glad to have him on the staff." He made him — along with me — one of Breit's team.
Cornell:Did you talk with Fleming about the decision to hire an additional physicist?
Tuve:I don't think so. I think it just happened. Of course, we welcomed it.
Cornell:But you had talked to Hafstad about coming.
Tuve:Well, that came later. That was a year later.
Cornell:Was that for the radio work or specifically for work with the Tesla coil.
Tuve:It was for both. He did quite a bit of the radio work. And so did I really until 1929. It wasn't easy. We didn't have money to build a powerful transmitter, so we leaned on our naval research friends, Eddie [E. O.] Hulburt and others. Dr. [A. H.] Taylor. And [L. A.] Gebhard, who ran the transmitters. And [M. H.] Shrink — what was Shrink's first name? I've forgotten. Lou Gebhard and Shrink. Begins with M but I don't remember. They ran these for Navy communications. They were 20 kilowatt, water-cooled tubes. We'd pulse the vernier stages, the exciter stages with our multivibrator thing. But this echo-interference method was quite interesting. By letting the crystal leak over to the receiver that way — phasing it — we had, so to speak, a fine structure on the motions of the upper atmosphere. It would change very rapidly some periods, and other times it would change very slowly. We made some photographic records, brief ones, not continuous things. The continuous recording of pulses came after Berkner came in 1931.
Cornell:So really they were two separate projects.
Cornell:Did you use any similar techniques, or skills.
Tuve:Electronics. We were doing spark electronics with damped waves with the Tesla coil. They were just enormous power if you tried to run it continuously. Let's see, you asked me about whether we were hired for that. I was going to make a remark, but I've forgotten what it was.
Cornell:Would you say that the radio work you had done as a youngster developed continuously.
Tuve:Oh, no. There were discontinuities. I stopped amateur radio when I was a freshman in college because it takes too much time to play around with radio. So although I studied some high- frequency things under [C. M.] Jansky as an engineer, I wasn't really committed to radio. I was committed to small currents, electronics, that sort of thing, but not necessarily radio communication. Under Jansky there were half a dozen of us in the Engineering College there at Minnesota that set up what we think was the world's first broadcasting station. We had an experimental license, 9XI. We broadcast crop reports, which was the principal item. Some of the headline news, crop reports, and music. When it was my turn on this as disk jockey I played classical music — Bach, Beethoven, and so on. [laughs] It was quite fun. The farmers over quite a radius of the state picked it up with their crystal sets.
Cornell:Had you started that project?
Tuve:No. Jansky started it. He was associate professor in electrical engineering there at the time. And then in physics I was working on bombardment with positive ions to see what's the ionization of positive ions in gaseous media. The answer was less than one seven thousandth. I didn't realize that that was a suitable thesis, too. I was looking for ionization all the time. Finally, I just set limits on it and Jack [J. T.] Tate practically had to beat me over the head to say: "Well, don't you understand? That's a thesis, too." These were mercury ions bombarding something or other, I don't remember.
Cornell:How did you choose that topic.
Tuve:Oh, I had been reading Rutherford and atomic physics and the general notion of beams and particles. It was fascinating, so I did some of it. I wanted to learn all the techniques of vacuum production, glass blowing, and — you know — go through the trouble. That's when you love a subject, if you have a lot of trouble with it.
Cornell:So you didn't take up work with radio techniques until Breit came up with this project.
Tuve:Well, I had been working on radio more or less all my life. As I say, at Minnesota one of the experiments I did was to set up these — we had some surplus Navy tubes, called J and E tubes. They were 5 watt, round Western Electric transmitter valves. We had a bunch of those on surplus. So I took four of them and removed the bases and hooked them in parallel and tried to make as short waves as possible. I got down to 82 centimeters, I think it was, measured on Lecher wires.
Cornell:Who did you talk to about your work at Minnesota? You said you and Breit would talk.
Tuve:That was after my experiments. My experiments were practically over then. Who did I talk with? Well, we talked with the other graduate students. There wasn't anyone especially interested in high frequencies in the physics department. But it was a good physics department. They were interested in everything. They encouraged you in whatever you wanted to do. So I did those two things. First I played around at the time that we were doing this broadcasting, which was six months before KDKA. KDKA at Pittsburgh is supposed to be the first broadcast station. Well, they're probably the first paid broadcast station because, of course, this was unpaid at the university. But it was well in advance of [Frank] Conrad's work at Westinghouse. That was the place I got these extra E tubes.
Cornell:How did Tate become your advisor there?
Tuve:By my request. He is an enormously attractive man. I had studied what he called "Introduction to Theoretical Physics," which was a first-year graduate course. I took it as an undergraduate. He was an absolutely charming and a very wise kind of a person. The impression was that he was youthful.
Cornell:Let's see, you were talking about your different careers.
Yes. School. Then Carnegie up 'til 1940. And then the war years, when we did the proximity fuse and ran a big lab. You might be interested in some of that work, too.
When the hydrogen bomb came up, I was one of the twelve signers of the petition to Truman not to develop the hydrogen bomb, and we gave a number of reasons. But we missed by a day being culprits. The next day he announced his decision that they would go ahead with the hydrogen bomb, Teller's bomb. We all felt that Edward Teller was paranoid and extreme in his views. He always has been. We felt that a lot of these things should be slowed up. No reason to push the Russians into competing with us as intensely as they had. But the size of the devastation produced by the first H-bomb in the Pacific was kept secret for a year and a half by Lewis Strauss. And I almost busted knowing these things people were not allowed to know then, because this is a different order of magnitude even from ordinary bombs. Well, that was part of the stress. Meanwhile I was just encouraging geophysics. They made me director of the Department. And I said: "Well, I think Mr. Carnegie wants good research done. If you can't do anything in terrestrial magnetism, we'll do it in other parts of geophysics. But I think the thing to do is to do it yourself. Get in trouble. Go out and make some measurements. Make some mistakes. That's the way you learn to love a subject." So I always insisted that instead of just interpreting other people's data the men go out and get their own data and have enough struggles in the field that they would just love that precious data when they got back to the lab.
Cornell:Was that not possible in nuclear physics any longer?
Nuclear physics, no, had been taken over by the big shots, so to speak. Los Alamos, of course. Oak Ridge. Chicago. And Berkeley. It was a business. There was high competition. Everything was serious engineering work, not just personal experimentation or personal knowledge and interest in finding a few spectrum lines or something like that. Everything had to be applied. What did this indicate for atomic piles or atomic bombs, and so on? What could we accomplish, with all those billions being available for anybody that had any notions at all what to do? How could we amount to anything? I did not intend, or I did not feel that it was appropriate for Carnegie people to just manage government money. If you want to do that, let the government hire you and manage government money. There's no business for a completely free private organization to do that, although many did. Swarthmore, for example — the Bartol Foundation — and places like that. But [Vannevar] Bush and I were of one mind on this, that we should keep free from undue expansion.
The idea was, as he expressed it, to pay our own salaries. As long as we didn't take government money from somebody for paying salaries we were reasonably safe. We prefer not to take government money for anything and so pretty much we didn't—although I set up the arrangement that we would spend money for other people (particularly international things) with government money. We'd be quite willing to do that, as long as we were paying our own share of our own part of it. Let's see, were there any other exceptions? No. That was the principle exception. This has worked reasonably well, I think. We took fellowships from government money after a while — for example, NIH fellows when we were doing biophysics. But this was a matter of support. They were actually fellows attached to NIH who did their work over with us. But we considered them part of our team. So that was the fourth part of my career, which was essentially retiring to be a private person and going into explosion seismology, partly by circumstance. I had heard that the Navy was going to destroy some three hundred million pounds of TNT. So being a close friend of the Chief of Naval Ordnance, I went to Admiral [G. F.] Hussey — who was the chief then — and asked him to hold some of it for explosion work for Carnegie. He says, "Well, how much would you like?" And I said, "Oh, how about a hundred million pounds." [laughs] "Fine, what about a hundred and fifty." "All right, a hundred and fifty million pounds." So they put my name on a hundred and fifty million pounds of TNT in the Dugway munition storage place out in Utah and other places. Along came the Korean war and the ordnance people found my name on a lot of things and I got called in.
Would they return to themselves some of the powder that was allocated to me? So I financed the powder for the Korean war. [laughs] But we had plenty of explosives available. And it seemed reasonable to settle some of the discrepancies in seismic studies. For example, there was an outstanding discrepancy between explosion seismic measurements in California under [B.] Gutenberg and Gutenberg's own interpretation of the earthquake things — they give different layers, and so on. Well, it turned out that Gutenberg had misidentified them, but we never published this. I asked him to publish it. But I don't think he ever did, except by publishing new values. He didn't call attention that there had ever been a mistake. [laughs] I don't blame him. We were upstarts. But some of the arrivals that they had identified were not what he had thought they were.
Cornell:Who were you working with at that time?
Mostly I started out by myself. I had a son who was fourteen, or something like that. Let's see — who did I work with? Well, anyway, I went out to New Mexico because Jack [E. J.] Workman, who had been one of the fellows with me in the war work had a lab there at the physics department in the Manzano mountains near Albuquerque. There was a place where we had set up a proving ground, and that was a perfectly good place to start the seismic explosions. My son went with me on this first trip. That was 1947. I guess in 1946 I went out just briefly. But in 1947 I went with rather crude seismometers. We started the survey — first one, five, and twenty kilometers distance and then we got up to about a hundred kilometers distance and greatly developed the seismometers and the amplifiers, recorders. Well, this was returning to a sport. Of course, in the Department I had other interests I had to foster. One was what to do about the ionosphere work. The Carnegie had taken over half the world for ionosphere work and the British had taken over the other half of the world. So we had stations all over, from Greenland to Alaska to — where was the farthest place? Out in the Aleutians somewhere. Russia was not a good place to travel or collaborate. Japan was an enemy. We measured in — there was something like a dozen stations running continuously for ionosphere measurements. I arranged, in fact, to create a whole new section of the Bureau of Standards — the Central Radio Propagation Laboratory [CRPL], we called it — which was a combination of our friends in the Army (the Signal Corps), the Navy, and Commerce (Bureau of Standards). I guess that was all.
Anyway, the half dozen people most interested in radio for the government were included. And then I transferred all of our stations to them. But we inherited one or two people with it. Berkner came back with us. So did [H. W.] Wells. The problem was what fruitful thing they might do. Berkner was his own — he was trying to make things automatic so that nobody had to be there and still get all kinds of measurements. He never got it finished. It was too complex. But he had a grand design, which filled a trailer full of electronics that I had him haul to Brookhaven when he went there. Wells measured a number of things for fairly long — radio astronomy. Berkner was after ionosphere and upper air studies, but Wells was interested in the radio astronomy side of it. And he continued this for some years.
Cornell:Didn't you get interested in radio astronomy at the time?
Tuve:Oh, yes. I was chairman of the radio astronomy committee for NSF for some years and started it. Among other things, I personally made the suggestion for the San Augustin Plains from my own seismic experience with Jack Workman. That was an ideal spot for the big array. I guess I was the one that selected Green Bank [West Virginia]. Berkner had insisted on getting some measurements. It turned out to be — what do you call it — like preventative medicine, to protect you against complaints of other people. Get some engineering firms to make a bunch of measurements up and down the various places that we might think would do, under the restriction that we wanted to be somewhere essentially in the East, not in the Far West so it would be close enough to the centers. Well, I pointed out that nobody among the engineering fraternity measured anything smaller than a hundred or a thousand times the radio signal noise that we were concerned with. It made no sense to make observations down to such low limits of sensitivity. "Well," Berkner said, "It made some sense. At least you haven't a big squawk going on all the time." I said, "Yes, you can do that in just a simple automobile trip." But he insisted that we spend a lot of money on it — about a hundred thousand dollars or something like that — to examine various places. We got the reports all bound up and so on. It made it possible to select Green Bank, which nobody has criticized. [laughs]
Cornell:How long did you continue your research activities?
Tuve:Well, I went on even after I retired. I was busy measuring the hydrogen clouds of our galaxy at that time. How long did I continue? I was active with the seismology, especially before IGY. I was a member of the executive committee — I think there were four of us — for IGY, International Geophysical Year, in 1957. Starting about 1953 or 1954 I became quite active. I was concerned with improving the seismic things. We had made a number of expeditions, first around Virginia, Maryland, and North Carolina and then extending — let's see, where did we next explode things? Up in Hibbing there were big explosions in the iron mine country. So we examined that all the way through these various geological formations, extending down into Wisconsin and over into Minnesota. We made measurements in Puget Sound. We made measurements down in Silver City, New Mexico. What is this mine that's over there? It's in Arizona, just on the border. Well, anyway, the Arizona/New Mexico region. We were measuring out, in general, to about three hundred kilometers — three hundred fifty — to get to the PN, the high velocity layer. All this time I was working closely with Howard Tatel and others on radio astronomy. We designed the dishes which are used. We designed them and then asked Blaw-Knox to make engineering drawings. So they called them Blaw-Knox dishes. But they followed all of our designs bolted together, except they converted from I-beams to angles or channels. They were bolted together, riveted together. They made changes for manufacturing reasons.
Cornell:Didn't Howard Tatel start off his career in nuclear physics?
Tuve:I don't remember what he did before he came to APL. But he was one of our strong men at the Applied Physics Lab from 1942 to 1946. And he was working with [J. A.] Van Allen on counters, high balloons, and rockets at the time that I persuaded him to come and join us and do the seismic work and radio astronomy both.
Cornell:Did Richard Roberts start off in nuclear physics?
Tuve:Yes. I've forgotten what his thesis was. I'd have to look that up. I think it was something to do with particle physics, like radioactivity, ranges — I don't remember just what. But in 1937 he started right in with our tubes, measuring disintegrations and so on. He's the one that discovered delayed neutrons — which is the only way that you can control an atomic pile, for example. It just was luck that such things exist. He found that about 1938, I guess, he and Hafstad.
Cornell:Was he still doing nuclear physics after the war?
Tuve:No. He went into biophysics, pretty much at my prodding. We'd hold a staff meeting once a month, but mostly we'd talk around the lab. What were the interesting things? And I continually held before them: "What are the significant things that a completely free investigator might do, more or less starting new things, not just routine measurements of old things, and not just big operations carried on with government money for somebody else's purposes. Where is the proper niche for a nephew of Andrew Carnegie?" I used to tell each man that was appointed: "When you're a Carnegie man you are a nephew of Andrew Carnegie and behave accordingly. For one thing, don't take a lot of big risks with money. A hundred million dollar concern has to be careful because they are liable for any suits."
Cornell:What else did that mean? I hadn't heard that before.
The thing it meant was that had Carnegie said, "Get a good man and support him." That's all his instructions were. And so the thing is: "Make use of your freedom. Don't just try to get something into the annual report. Do something that's important, even if your answer is no." I learned from Tate that a negative answer was important. So I said: "If you can outline what's a really important problem to think about, that's very worthwhile. And that's something you do with your own brains. It isn't something you can get a gang to do for you." I tried to hire people interested in terrestrial magnetism, but there wasn't anybody except for very dull kinds of things. There was [J.] Bartels. He was a statistician, essentially. And [S.] Chapman, who was much wider ranging in his interests. But if I couldn't find people interested in terrestrial magnetism — well, let's do other kinds of geophysics. We had done the ionosphere work early in life, and that's simply a sample of what can grow out of individual activities and interests.
So along with this I was busy trying to identify what were the important things that an individual might do. And I couldn't help but say that biophysics and a numerical kind of biochemistry was certainly the kind of field that was going to expand in the next 20 years. So I persuaded Bush to let me set up a biophysics section. Almost he didn't permit it. He said, "Merle, I've got to support you in what you want to do until I fire you." [laughs] He tried to get off the hook. He tried to say, "Won't you really back off from this and think for a while." I said: "No, I think now's the time to do it. Nobody else is doing it. I've got a couple of men that are interested in it." Roberts had come down with me to the President. "We've got Hugh Darby here. We have [R. E.] Smith from plant biology who's been working with us. I think we ought to set up a real biophysics lab." At the time we were making some isotopes for them, things that they couldn't get from atomic piles. I said, "That's just a service task. I think we ought to cut it out as soon as we can." Bush said: "What! Not use the cyclotron." I said: "I'm afraid that's true. It took a whole world war and the atomic bomb to make it obsolete. That ought to be enough." [laughs] So we did biophysics. Roberts was more or less the chief of that. One time I had [P. H.] Abelson as the chief. But we didn't worry much about titles. We just worked together.
So that was a group of essentially [D. B.] Cowie, and Roberts, and Ableson. And we had several visiting members. But it made good use of the cyclotron laboratory that we had. Of course, they were part of the general group of what I see as numerical biophysics. Among their tricks were pulses. You'd take a labeled reagent, pulse it for a certain time and take it away again and study in vivo the various incorporations, synthesis, pathways, and metabolic changes. And the other one was flooding the substrait. In other words, you'd grow it with radioactivity for a certain time and then you'd completely flood with the nonradioactive form of the same substrait and watch the k-curve, getting numerical things on what goes on. They did a lot of work with E. coli, and later with genetic complexities — including what they called satellites, that is, these multiple gene units up to a hundred thousand times all the same. It was rather interesting — first the problem of proving that they were all the same, and second trying to understand what it's all about. Well, those are the different parts of my life. Now I'm just trying to stay on my feet.
Cornell:You're doing very well.
Tuve:It's pretty hard. Just so the brains don't disappear. I understand senility affects a certain percentage of the people that get the shakes. No, I'm still trying to picture what a Ph.D. thesis in history of science really is. You can summarize what I've done, but that's no Ph.D. What is the original research part of it? That I'm not sure.
Cornell:I started being interested in physics, but I realized in the course of my studies that I was interested more in how people would come to do physics as a distinctive human activity and how it fits into the climate of the times. Why would nuclear physics take off in the interwar period? And in the case of your career, why would you come to leave nuclear physics as an active area of research after the war? Those are your personal decisions, but they reflect the climate of the times.
Tuve:I should modify them a little bit. Actually, nuclear physics [at the DTM after the war] wasn't entirely without support. It was clear that that wasn't the place we should expand into. But we had several people still with much interest in it. Heydenberg had done the nuclear forces with us, you know, and he stayed with the machine measuring polarized protons. First it wasn't polarized protons. First he and –-
Temmer. George S. Temmer. George Temmer was doing standard kinds of nuclear physics — low energies, energies up to 1.2 million with our electrostatic generator and up to 3.2 million with the newer one. It takes time to do these things. In the course of a year or so the question was whether we should make an investment in a bigger and better machine or what. And then Florida –- Tallahassee — got a government grant. A lot of people were building these big Van de Graaff generators under pressure and Florida was hunting for somebody. They wanted to hire these people. And I said: "Why don't we do that. Let's find out if this is the kind of thing that you want to be a part of, because this is orchestration of government money — yet they do need some help there in Florida. Why don't we just give you leave of absence with pay. Go ahead, go down to Florida. They can pay you something, at least maybe half salary, or something like that, and make it feasible to move around, do a lot, give you some expense money. But you stay with the Department as part of our staff." So we did that for several years 'til finally it was clear they were in a good niche, and they liked it there, and there wasn't any pressure from the government to do something else. So then we let them slide back onto the university payroll there. That worked pretty well.
Meanwhile Lou [Louis] Brown had come over from Switzerland, from Basel, with Professor [P. Huber] — begins with H — well, the professor of physics at Basel, who had worked with polarized protons at low voltages. He knew how to make a polarized beam— various magnets and so on. So Lou Brown undertook, with the help of the Basel group, to supply a polarized ion source in our machine. That occupied six, eight years. I am so embarrassed to not remember Professor — it has an umlaut "o" in it. It's Haber. No. It's close to that, but it's not Haber. So Lou continued for quite a few years — maybe fifteen years — with the polarized proton work, until that was pretty well cleaned up for any voltages and ions that we could work with. Lou has since worked with Tom [L. T.] Aldrich on mass spectrograph studies of ancient rocks, age determinations, which I started in 1947 by calling one of [A. O. C.] Nier's men, Tom Aldrich, who was down teaching at Missouri after taking his Ph.D. with Nier on mass spectrographs. I brought him in to work on — if he was interested — ages of rocks, radioactive dating, and that's been continued since.
But these choices were made with deliberate attention to the idea of something that's suitable for a nephew of Andrew Carnegie to busy himself with. If you are as free as that, what are you going to do? It's a bit too challenging for some people. I had some other problems. I inherited some older men — men near retirement age, in their sixties — when I became director. One of them was [G. R.] Wait and the other was [O. H.] Gish. And another was [W. J.] Rooney. Wait and Gish were interested in accounting for the atmospheric current. You know there is a current from the upper atmosphere to the ground, all the time. Where is the return current? They had guessed that it was probably due to thunderstorms, because thunderstorms largely occur over ground, not over ocean. So by knowing the distribution of ground and the distribution of lightning over the course of twenty-four hours, which you can find by radio, they had concluded that it is really lightning that must be charging up the atmosphere the other way. But it had never been proved, and how the devil do you prove that? I said, "Let's fly over the damn tops of these cirrus puffs." This was sixty thousand feet. Well, no airplane could go that high, except a B-29 in extremis. With a B-29 running all its engines at full power — which you are not supposed to do — for an hour you can get up to fifty-five to sixty thousand feet. They even went to seventy thousand.
The Air Force wouldn't let our men ride them because they were old men, but all the instruments were supervised and calibrated and so on by these men and they found, yes, a direct reversal when you get above a thunderhead. Your electric field changes sign, and there's a big electric current the other way. So that's how the charge to the upper atmosphere is replenished. We burned out, I think, eight sets of engines on the B-29s. But they were surplus anyhow. They'd make one flight with these four engines and they'd have to junk them and put in new engines each time. And they had, I suppose, close to a dozen flights. It was, I thought, a pretty satisfying result for a couple of old men in the last two years of their research lives to put out as pretty a thing as that. But there again it took some nudging to expand their imagination to think that they can do something instead of just following some potential gradient on the ground in Mexico or something like that, which was almost meaningless.
Cornell:Who first told you about Andrew Carnegie's nephew?
Tuve:Well, that's my invention. I was trying to get the people to realize the validity of their freedom. I said: "It'll take a while before they fire me. I may get kicked out for this, you know. I'm not sure but what that's what I would do if I was president — have a wild guy decide as a director he'd do whatever they pleased. As long as I'm running it, I'll give you that protection. It'll take at least six months, or a year before anybody'll fire me, so let's try it."
Cornell:Was your style when you were director at all like Fleming's?
I don't think so. Fleming, although I didn't appreciate it really at the time, had a very broad appreciation of what research was. He was, of course, a geophysicist, interested in world relationships — tremendous amount of correspondence and friendliness that way and an attention to detail. He was a detail artist. But he did it well. But, no, except for this preoccupation with what is the next field of opportunity where really freedom is an important ingredient. That obsessed me, I suppose you'd say. And to that extent I was an opportunist, just letting people be interested in things that were striking. I was always myself interested in extremes: extremes of pressure, extremes of heat, extremes of voltage, extremes of distance, extremes of time, extremes of smallness, anything like that. My father interested me in astronomy when he was scoutmaster. He used to point out the constellations and tell the boys this and that about the stars. Remember that was 1912 or 1915, and a lot less was known. But at least we could find Aldebaran, Sirius, and some of the other stars.
The idea of distance and time had its birth there, a fascination which has never left me. I've been interested in quasars and so on, essentially in continuous interest since I was a boy. How did it come about? Well, as I say, it was fun to play around with — they were the modern things. The telephones, and the magnetos, sparks from the Ford coils and things like that were more modern than raising calves or the best crops. Chemical fertilizers were looked at askance at that time, you know. Oh, yes — that was artificial, even in the 1920s. Ernie worked on a farm once when we were in high school, about 1916. A corn cultivator sliced his little finger. It was crippled from that time on. I worked more in town, just odds and ends. But fertilizer wasn't something that you did, except manure. There were some tentative stabs at trying it, spectacular greens that you got. [laughs] So Ernie and I both got well acquainted with the telephone linemen in the small town of Canton (2600 people) where I was born. Mike Leffert was one. Who was the other? Sweeny or something like that. It was all very interesting, the way they hooked up wires and the way they tested things and checked things through cables.
Cornell:Where would you see them at work?
Tuve:Just along the streets. Then I made my way to the telephone office just to see what it looked like.
Cornell:What did you see?
Tuve:Well, mostly I remember seeing Verne Kennedy. His father owned the telephone company of the local county. He was a freshman at MIT. I came down one day — Ernie and I — to see about the way they wired certain circuits, branch lines, trunk lines, or something long distance. Of course, this was all hand operations. And he brought out a slipstick. I had heard dimly about slide rules, but never had seen one. He brought that in, and we had him multiply numbers, and then we'd multiply them out, and damn it they checked! [laughs] Ho boy, is this wonderful! Here was a stick that would do arithmetic like that! So I was envious of Verne Kennedy.
Cornell:Did you keep up with him at all? What did he do?
Tuve:Well, he was a generation — he was older than I was. So it wasn't natural to keep up. No, I don't know where he went — Chicago or some place after he finished MIT. Actually, funny thing, I hired his firm to do some things for us when I was director of APL. Then I ran into him again, called on his wife and himself with my two kids when I went through Evanston one day. I also knew his wife, who was a close friend of my aunt's at that time — by the name of Whitlow. Well, as far as I can see, I was always interested in electronics of some kind or other. I was especially interested in the first audion tube. The first de Forest audion that I saw was when I was a freshman in high school. We went down on, oh, some kind of—we sang in the glee club, or something. We went to Sioux City, and I visited the home of Dr. White. His son — I've forgotten the son's name — had a real good spark transmitter and receiver. And he had a pair of de Forest audion tubes for his receivers. If one failed, the other could be switched on. That was the apple of my eye, and Ernie had the same envy. So we went back and we worked for the local club in town who wanted to make a nine-hole golf course. Ernie and I prepared the greens for that. They made sand greens — winter greens — because we didn't have any way of really keeping up good grass. So they went the whole hog and just made them all sand. We built all nine — both the tees and the greens, so called. Made a hole in one once, too.
Cornell:Oh, you played.
Tuve:Yes — after we'd made it, a couple of years after.
Cornell:How did you and Ernie Lawrence differ in your interests in radio? Did you share a lot of the same enthusiasm?
Tuve:I guess so. Maybe I was a little more rambunctious. I would try to do more different things. Ernie mostly did his experiments over at my house, although we persuaded his cousin Oliver Overseth to set up a transmitter and receiver at the other end of town. How did we differ? When we got these audion tubes, Ernie bought the Audiotron which had two filaments—so if one burned out, you still weren't dead. I bought the real thing, the Type-T de Forest Audion, which had a single filament. After a year's use it went. It was sad. I tried everything to fix that. I even tried melting the glass — just soften it enough so that the wires could touch and hope to weld it together that way. Unsuccessful. [laughs] Ernie used loading coils, big tall ones about this diameter and this high. I used a Clapp-Eastham tuner which had a primary like that, and a secondary about that long. Smaller diameter. Slide in and out. I bought simply the coils from Clapp-Eastham and some contact points and switches and made it up together.
Cornell:So Ernie's was about four inches in diameter?
Cornell:And about two feet tall.
Tuve:Oh, two and a half or three feet tall. It was quite a long, tall thing. He had two of them, for wavelengths around 5000 meters and 8000 meters. I listened each night to Nauen and Hanover, POI and OUI, and Tuckerton, New Jersey. I would get the time signals first from Arlington and then get the news from Arlington and then get the other news from these two stations or just transmissions that they gave.
Cornell:What did your parents think about your interest in radio?
Tuve:"Merle, now you stop this and go to bed. You won't be any good tomorrow." [laughs]
Cornell:Who would say that?
Tuve:Mother [I. M. L. Tuve]. I'd have to sneak in something. But they were supportive. It didn't take much support. There wasn't any way to buy anything, you know. They had to put up with a certain amount of nuisance — digging way under the foundations of the house to get a good ground, down where it was moist, and putting antennas up from the chimney over to the garage.
Cornell:Were there two sets involved?
Tuve:Yes. Ernie mostly would monkey with mine, although he did go in — after I got that long wave stuff going — with this other way of doing it and worked pretty well. But he never really became an intensive amateur, I think partly because they moved to Aberdeen, South Dakota, for a year or so and then came back again to Canton about the time we were thirteen or fifteen. But our work together with the radio overlapped. After they had moved back to Canton was the time of the golf course, the long wave receptions, and so on. But mostly for transmitting he tried to get to his cousin Oliver's house, because that was a mile and a half from our home. Ernie and I lived across the street from each other. Not always. After they came back from Aberdeen, they lived down near the high school, about a mile away.
Cornell:What did your schoolmates think about your interest in radio?
Tuve:Oh, gosh, I don't remember having much discussion with them — no. But it was very important to me when I was in, let's see, my second year in high school. Actually, I was attending a Lutheran academy, that my father had been head of for some years. Professor Minne — M-I-N-N-E, Norwegian — taught physics from Black and Davis, which was a very nice textbook for high schools and introduced me to the wonders of mechanics and heat and a whole lot of things. Oh, I just ate that up. That made a big difference. But that was a relationship with Professor Minne rather than with classmates. I don't even remember who was in the course with us — only two or three, just a few.
Cornell:How did you happen to change from the high school to the academy?
Tuve:Well, my father had just stepped down and was replaced by Dr. [P. M.] Glasoe, a chemist from St. Olaf College, Northfield, Minnesota. He and the local preacher came to my dad and said, "Listen, it doesn't look so hot if you don't send your son to this school and send him instead to the public high school." I butted in when I heard this and said: "Well, it's because of the cost. I don't have to pay anything if I go to the high school." So they said, "Will you go if we pay your tuition, give you a scholarship for your tuition so you don't have to pay?" That pretty much trumped me, and I said, "OK." Then I had an argument with the German teacher about the first week [laughs] I was at the academy. He had cast some reflections on my mother, or something or other — some trivial business. Well, I got thoroughly heated up over it. I had tried to get Latin. They didn't teach Latin II that particular year. But I knew I could get it down at the high school. So I resigned from German — canceled it out — went down and took high school Latin instead. So I was going to both places for a while, for a year. Well, this is very thin gruel that we're providing for a Ph.D. thesis.
Cornell:Well, you have to remember that life before World War I is a totally foreign world for me.
Tuve:It was, it was pretty foreign.
Cornell:You're telling me things from your own experience that are wholly outside mine, and it's very helpful to hear what you have to say. And another thing, too: it looks like you looked at several different things before you came to physics — radio, chemistry, music. I am curious about the careers you considered and then put aside.
Tuve:I suppose a good deal of it came from Professor Minne at the academy. It was my first introduction to physics in a more qualitative way than — well, it was quantitative too. Black and Davis is a serious text. Some colleges used to use it. It was well done and it was sufficiently various. It covered many things you know — mechanics, electricity, heat, magnetism, and so on. That was followed by college physics with [H. A.] Erikson and [Anthony] Zeleny, a standard engineer's tour with lots of problems. It just excited me to have these kinds of puzzles illuminated, to be able to study them. So I signed up for theoretical physics, because — because what? I had seen something of Tate. He was a mysterious young chap at the time, although he was a full professor and was quite young. I hadn't been in his course for a week but what he was just the apple of my eye, so to speak.
Cornell:Didn't you at one point have a serious interest in chemistry?
Tuve:I was going to major in chemistry. That's what I signed up first. I kinda got scared out. It was too much memory work. Well, actually what happened was I had taken a course in college chemistry — it really was — at the academy, and I was perhaps still a little confused. There's so much rote knowledge required. I asked the University of Minnesota — I entered in the spring quarter, April 1919, nine months after my father died — and I asked for advanced credit on some things, including a course in chemistry. I said, "Can I start with the class that began last fall?" They said, "Well, if you think you can do it." Well, it was all I could do. And it scared me out of chemistry, because it was so much you had to know. You couldn't predict it — you just had to know it — whereas in physics you start with a few fundamental constants, and that's mostly what you use.
Cornell:Where had you gotten interested in chemistry?
Tuve:From this Professor Glasoe, who was head of the academy in my father's place. He was a good teacher. I had felt that it was a better a preparation than — I overestimated it a little, I think. Although I got through chemistry, it scared me. [laughs] So I switched to electrical engineering in the autumn. I went to spring quarter and then the summer session, which was half of a quarter. Then I started the engineering course more or less indeterminate whether I was a freshman or sophomore. I was in between. But I made up all those things in a hurry.
Cornell:Where did you get the idea to do electrical engineering?
Tuve:Well, from being a ham radio operator. I had always had various magazines — SCIENTIFIC AMERICAN and electronics magazines and things — so I knew roughly the scope of engineering.
Cornell:What about your older brother?
Tuve:My brother [G. L. Tuve] became a professor of mechanical engineering. At the time he was just finishing college — when I was a sophomore.
Cornell:Did that influence you at all?
Tuve:Yes. When I was in South Dakota and he had come home from summer vacation, he had explained what engineering was. Up 'til then I didn't really know. It was locomotive engineers and other kinds of engineers. I had paid little attention. But he brought home a book called MECHANICAL TECHNOLOGY just for side reading that summer, which introduced all kinds of mechanical operations, how they're done. I had read through a lot of that, and it gave me a notion of what mechanical engineering was about. I wanted to learn the equivalent kinds of things about electrical apparatus and procedures. But I never was terribly interested in big currents. I was a little afraid of a hundred-thousand-watt power plant or something like that. That would scare me. Or a great big motor. I didn't like that.
Cornell:Where had you seen big motors or large power plants?
Tuve:Well, aside from things like the street-car substations where they had big converters, where they changed from AC to DC — what do you call that? Converter? I've forgotten. Anyway, in the mines up at Hibbing — I hadn't been there, but I'd heard about the size of the things that go on and, of course, seen a lot of pictures.
Cornell:Did you go from engineering to physics because you were dissatisfied with the engineering or because you liked what you saw in the physics or a little of both?
Tuve:Because I liked what I saw in the physics. Engineering was all right, but it was more humdrum. It was more routine. Friends of mine had gone to the telephone company, and they were stuck there fifteen years later. It looked to me like they were stuck, whereas they were having a perfectly good time. But it wasn't anything like research, where you're gambling all the time. [laughs]
Cornell:These were friends from Minnesota?
Tuve:Yes. Why don't you take a quick gander at this [draft transcript of an earlier interview] — especially the latter part of it. It makes me look as though I were incoherent or something. The questions have to be there. Otherwise it is very disconnected. So what I was thinking was to say: "Well, I prefer not to have much use made of that summary." But I don't have any objection — there's no secrets in our discussion, although it was a different aim. For example, he wanted to know from me whether I had had something to do with the election of the next [CIW] president and that sort of question. Well, I ducked most of it. Most of it the answer was no, and so on. Things like that, which have no business in my biography or any place else. If you'll ignore those, then I don't mind if you listen to the tape.
Tuve:But I prefer that you don't have the tape copied and distributed. Same way with this thing. Why don't you take it along. It'll give you a notion of what's in there. Then return it. Oh, I should have given you a copy of the letter I wrote [Ray] Bowers, which was essentially what I've said — that it's not a good representation of what actually went on, because the questions were omitted.
Cornell:One thing I am curious about. This will be a one-shot thing and then we'll call it a day. Do you remember Frederick Cottrell?
Tuve:Sure, I should say.
Cornell:We have to do a first-year paper in our department, and I did my first-year paper on the early history of the Research Corporation. So I'd be interested in anything you might have to tell me about Cottrell.
Tuve:Oh, he was quite a live spark. He had all kinds of ideas. About government, for example, he said, "No laboratory lasts more than" — let's see, how many years was it? I think he said twelve years. He said, "The first couple years it's hard to get started." Then he said: "The best years are the seventh to the tenth years. But after twelve, thirteen years every laboratory goes dead. It ought to be cleaned out, started over again, like you do in a garden." He was a very independent kind of a — he was a government administrator, many times in different posts. He started the Fixed Nitrogen Laboratory, for example, in World War I. It had evolved into a research group doing infrared and ultraviolet on plants, things like that — and spectroscopy — really quite decent studies. Also there was an applications group associated with them. This was in the buildings of the American University, at the time that they were too broke to even use their buildings. They ran pilot blast furnaces and things like that out in the country. Oh, he was very enthusiastic about our high voltage experiments. That's the kind of thing he liked. [laughs]
Cornell:He was in Washington, I guess, throughout all that.
Tuve:Oh, yes. He lived right on Reno Road — or right next to Reno Road — here in Chevy Chase. What things can I tell? Just the exuberance of his being. He listened! Well, he just sort of vacuumed you [laughs] he listened so intently. Then he'd add his own contributions and experiences, which were quite wide-ranging, from physics through chemistry. He always associated with youngsters, and he helped start the Radiation Lab for the Smithsonian down in the towers, and he encouraged that. He spent himself on other people a lot. He would go around and visit. He came over to the DTM to encourage us and so on.
Cornell:Can you remember specific instances when that happened?
Tuve:We had a discussion. We were a little disgusted about some of the rigidities in the Carnegie arrangements. That's when he brought out his theory that no laboratory is any good after about twelve years. They ought to clean it up and start over again. The best years are from the seventh to the tenth. It takes a while to get started. When it matures, well then it's really going strong. I remember that discussion occurring while we were making some adjustment or other with the high voltage machine. He had a kind of a nervous — well, his skin would flake. Oddly enough, it was from the nerve endings. What did they call those things? He would stand there working with his fingers like this. It was very irritating. Like very roughly chapped hands. If you've ever lived and worked in the cold you get really chapped hands that almost bleed, you know. He was that way nearly all the time. It was dermatitis, from the nerve endings, especially on his right hand. So you're interested how it came about that one got interested in things.
Cornell:And how one comes to change one's interests.
Contact with other people, I'm sure. They made the subject very interesting and it's a challenge: can you do something like that? Looks simple, you know. But any research I've ever done takes five years and you think you could repeat it in two weeks. [laughs] You just make lots of starts and stops and the delays come in and then you don't quite soak up the calibrations you need or something. Since you called, I've been reading the things in the period from 1932 through 1935 to see how come that it took us so long to get really going. Well, for one thing I wasn't too impressed by the success. We expected success in disintegrations. It was a bit disturbing in 1932 when [J. D.] Cockcroft and [E. T. S.] Walton came out with their measurements. But it was mostly disturbing because they found they could break down things like aluminum and silver and nickel — high atomic numbers, comparatively — at the same time they were doing experiments with protons. It might be one thing to have a proton climb over the barrier, but the barrier would be much higher for these other elements. They caught us with our pants down, so to speak.
We had just finished making a two-meter generator for which we had no housing, so we had to hurry up and make another generator — the one-meter machine — that we could put inside of the shed we had. The announcement, I guess, was in March or April, and it took until October before we had the one-meter generator with its auxiliary generator for the ion source and controls and the vacuum system, and all that. It's a complex thing to make it all at one time. That was in late September or October before we got going, and even then we didn't make measurements. We were doing something else first. So it was into December and early January before we made our first measurements of protons. But I was already convinced that this stuff was contamination. It would seem pretty obvious — same sort of ranges they got. But what the contamination was was uncertain. Immediately we figured that boron was a very likely prospect because we used borax on our hands — borax soaps, and so they washed the floors, and so on. What bothered me was here was the wonderful Cambridge laboratory with Lord Rutherford — it was Ernest Rutherford at that time — Rutherford right there, and yet they would put out such stuff, do such a bunk job and present it. Who are we to criticize Lord Rutherford's lab? So I shut up about it. That was a major factor in the next two years.
Then I found Lawrence came out with all kinds of reports of this and that. He thought that deuterium was unstable and breaks up on collision with other things. He thought there are thresholds on things — that this starts and that starts, thresholds of various kinds. Each week they would get a new element and they would get some particles from it and they'd announce the next week they had disintegration of something else. I just didn't feel like standing up and saying: "You're a bunch of liars, you guys. What's the matter with you? There's contamination all over the place." It was obvious enough that I said: "Let's wait for them to announce it. We don't want to wash somebody else's linen." But they didn't announce it. They just kept announcing more and more things. I finally went to a meeting in Berkeley and said right out that these things are due to contamination, it's clear. I made a little too much of a case for the opportunity. There may be a little of this and a little of that involved — gamma ray contamination with recoil particles and so on. But the secretary of Section B — it was an AAAS meeting — essentially reported that Tuve had said in his speech that all the discrepancies between different laboratories could be attributed to different voltages and currents, or something like that — and said nothing about contamination. So I wrote an answer in August — the meeting was in June — in SCIENCE, saying no, what I was saying in the abstract was absolutely true, that there were real discrepancies due to contamination.
Ernie never did admit that he had these. The contamination that was most bothersome, of course, was deuterium on deuterium. That was clear to us from the start. Because you'd get almost no contamination, but twenty minutes later there would be all kinds of contamination. So it was clear that something was building up. And the obvious thing was adsorbed hydrogen on the carbon and so on. Well, I spent a year being very blue that year because I didn't want to just call my friends for making such careless mistakes. It really smashed my idols in a way. I thought everybody was supposed to be idealistic enough to clean up his act before he goes into publication. But the rush was there. Ernie was, of course, trying to get more and more support for bigger and bigger magnets. That was his game. So he played up to the money boys and to the influential boys, which I didn't like to do. So that's one delicate period of my life which either should be forgotten about or very carefully written, because I stayed out of print then to avoid kind of slandering other people, and also because of a slippery subject. We were sure we were having contaminations. What other errors we might be having, it wasn't too clear. But I have no doubt that we were making errors. It's a new field. That's why it takes so long for the beginning of this. Here was the announcement in April 1932, and it took until January 1934 before we really commented and repeated and said anything about it. Then it took a year after that before it was on a sound basis. By that time I got to the main thing which we had set in 1926 as a goal, namely billiard-ball scattering, protons on protons. It was surprising that nobody else did it, except with radioactive source — which was pretty feeble. Milt [M. G.] White did that for a while.
Then we had Bill [W. H.] Wells make a bunch of cloud chamber pictures in our lab, which indicated it. I think there were two pictures out of ten thousand, or something — not enough to call it a measurement until we had been able in the course of about a year of work to calibrate the ratio to Mott scattering and plot it. Part of that job was getting a real voltage calibration. We had pretty monochromatic beams — by magnetic deflection. They were all the same velocity, essentially. We separated them out into molecular and atomic ions and so on. But if we were going to do absolute values of scattering, we had to know absolute values of voltage, too. That took quite a while. Ray [R. G.] Herb helped on that. I brought him over for the summer from Wisconsin in 1934. We knew that fluorine and lithium both had resonances. They were easy things to go by for calibrating where you were, checking your voltmeter. It took a while to establish the real values for those. But once we had those we were on solid ground, so we could make measurements. Then we made ratios to argon, scattering protons on hydrogen and protons on argon. We used the argon results as being classical and converted them to the Mott value for hydrogen, which verified our approximate calculations of the collision area simply by dimensions of pressure. But we couldn't do that better than about twenty per cent, whereas this other — the scattering of argon — we could get down to one per cent.
Cornell:Did you feel like you were putting more time into instrumental development than you had expected in the late 1920s?
Well, I'm afraid I expected — I didn't know what to expect. I regarded it just as part of the fun. Part of the job of being a physicist was to make your own tools and worry about them. We wanted to have somebody else provide us with high voltage. That was a kinda continuous disappointment for four or five years. In 1928 we asked for a bid on, I think, 900 kilovolts or a thousand kilovolts from General Electric, using condensers and rectifiers — kenotrons, they called them. But, hell, it was a hundred and fifty-five thousand and that was way out of reach for any Carnegie money. My salary at the time was probably around three thousand, thirty-two hundred. So one hundred fifty-five thousand was really quite a large sum in terms of man hours or man years. This Tesla, this damn Tesla coil! It was nothing but an irritation all the time. But it did enable us to do what we did. We managed to get gamma and beta rays — even proton tracks — all of them above a million volts. We had tubes that worked perfectly well the minute we stuck them on a Van de Graaff machine. So we got some things done with it. But the idea of being stuck with it all those years is really pretty punk. I was very blind. Well, for example, when [R. J.] Van de Graaff came over with the idea of just using a belt and charging it up, I said: "Well, Van, go and make some. We don't want to steal your ideas. This should be a Van de Graaff generator, not a Carnegie generator. We want to have one as soon as we possibly can." So he had a couple of them made up at the shop in Princeton — about 18-inch balls, I guess they were — and I brought them down on the car. [laughs] We found that DC worked perfectly well. But I didn't have an ion source rigged up at the time.
They were under some pressure and there was a meeting of the American Physical Society and Van had to have them back. So we brought them back but that would have been a year's head start if we'd had an ion source and stuck it on right then. Instead I accepted the delay. We first built the big one, and then we built the small one and finally got some measurements. All of this, however, was kind of announced when we started the thing, when I had the discussion with Fleming whether I'd go to Cambridge or stay at DTM. The idea was simplistic. All those positive charges in an argon nucleus must be held together by some force, some variation of Maxwell's equations, or somehow. It clearly can't be the ordinary thing. It's a very simple notion. So let's find out what that force looks like. And second, Rutherford's disintegration experiments obviously were a clue that something would be interesting to do — if you got lots of protons over the barrier. But then again, although we had [George] Gamow with us — I was the one that brought him to this country. Teller, too. I arranged with Dr. [C. H.] Marvin, the president of George Washington University to give a professorship in each case. He wanted to do something interesting and I said that would be a good investment in each of those cases, a couple of years apart. I was on some committee in the Washington area for improving the universities, or something. So we knew in 1928 of Gamow's calculations of the potential barrier. Then Breit wrote a paper in 1929 expounding how this would apply to nuclear physics, to proton beams and so on. But still I didn't try to do it at two hundred kilovolts. We could have done that. So I don't know, I've been kinda dumb all my life, but tried to stay in the right areas. [laughs]
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