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Interview of David Webster by W. James King on 1964 May 21, Niels Bohr Library & Archives, American Institute of Physics, College Park, MD USA, www.aip.org/history-programs/niels-bohr-library/oral-histories/4942
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Earliest associations with science; high school, through 1904, undergraduate at Harvard University under Wallace C. Sabine, Benjamin O. Pierce, George W. Pierce, William E. Byerly, William Osgood, Julian Coolidge, Theodore Lyman, 1910; graduate education, early teaching experiences and research in x-ray spectroscopy with Edward V. Huntington, William Duane, Franklin Hunt; University of Michigan, summer 1917; lieutenant in Science and Research Division of U.S. Army Signal Corps under Robert A. Millikan; aircraft stability studies, experiences as a pilot, Civil Pilot Training Program, 1939. Teaching at MIT, 1919; chairman of Physics Department of Stanford University, 1920-1941, development of department, Paul Kirkpatrick, Felix Bloch, early experimental work in theory of the continuous x-ray spectrum with Perley A. Ross, controversy about data and resolution of it; invention of the klystron by the Varian brothers, his contribution with William W. Hansen to its development; Sperry Gyroscope’s effect on department; civilian member of U. S. Signal Corps, early research involving rockets; return to Stanford after World War II, interest in teaching. Current research interests in solar wind and plasmas in the vicinity of the Earth. Influences on him of his early teachers, colleagues, writings of Henry Poincare, Max Planck, Hendrik A. Lorentz. Avocations and present personal life. Also prominently mentioned are: Joseph A. Becker and Arthur Compton.
Dr. Webster, when did your interest in science first begin?
I think it began when I was pretty well done with grade school. I happened to run onto a rather interesting book in astronomy in my parents' library, and my mother got me a book written for youngsters on chemistry, both of which were very interesting. I used to go out in the evenings and try to pick out constellations, and so on. I began to be interested way back there.
Do you happen to recall the name of the book on astronomy? Was it one of these field guides to the constellations?
No. I don't recall the name of it, and I'm not even sure who wrote it, but it was sort of a general book on astronomy, highly descriptive, non-mathematical, a popular book. The book on chemistry was called Fairyland of Chemistry, definitely a juvenile job, in which the atoms of various elements are compared to the fairies, some of them with one arm, some with two and some with four, and so on. But, you could get a lot of facts.
Did you do any experimentation at home?
No. We got a small telescope, a three-inch telescope which I used a good deal, and my brother was very much interested in chemistry. He was older than I was, and later on we did some experiments together but not an awful lot.
What kind of physics did you have in high school?
A good course, as good as they have that entrance exams would let it be, but unfortunately it did have a tendency to be dominated by Harvard entrance exams. However, it was a good course given by a mighty good man, Jams J. Greenhall, and he taught it very clearly and well.
Where did you go to high school?
Over in Noble and Greenhall, a private school.
This was in the vicinity of Boston someplace, wasn't it?
Yes, this was in Boston.
Did you do any experimentation in the laboratory in high school?
Oh yes, we had a good physics laboratory there, and we used E.H. Hall's text book and followed the line of experiments that he recommended. It was a good course.
Once you finished with high school, did you automatically decide to go to college and take up physics?
I automatically decided to go to college, and very automatically made it Harvard because that was traditional, and I thought I was going to be a chemist at that time, but then at the end of my freshman year, a member of the faculty who was supposed to be my advisor although I hadn't met him until then, called me into his office and said that — I think he said I was going into chemistry, or else he said to me what did I want to go into, and I said chemistry. One or the other, he said, "Well, you've been doing too well in mathematics for that, and mathematics would be wasted on a chemist and therefore you'd better make it physics." Well, I thought, well, it's interesting. I might as well give it a try and so I did. That's how I got into physics.
From whom did you take courses in physics?
Well, the first course was W. C. Sabine, Wallace Clement Sabine, who was a most excellent teacher, and in fact, my second course was with him, too. The first course was general physics, and the second one was light, and at the same time with the second I took a course in electricity with B.O. Peirce, and he was a mighty good man, too, mighty good.
Do you happen to recall any anecdotes about the undergraduating teaching in these courses?
Well, now, let's see. I remember Sabine making a remark once that he didn't think very much of the lecture method, because he said in a class of 150, as he put it, you can only appeal to the most elementary passions. Of course, that first course was very — just general. It covered all branches of physics, and I missed a large part of the last of it by getting an infected blister in my left hand, going out for crew, and being in the hospital a couple of months. But, I remember what I did get out of it was very good indeed.
These were lower level courses. How about work at the upper levels as an undergraduate?
Well, now let's see, as an undergraduate — that course in light, although it was in my second year, it was a course with only five students in it, and Sabine could give us very much his personal attention in that, and he had a method of running the laboratory in that which he described, as so far as he knew, the most instructive, but at the same time, the most destructive. He would tell us that he would like to have us do an experiment. For example, a demonstration of Young's fringes and he’d turn us loose in this big laboratory — it was a big darkroom divided into sections so that we could have different sections dark, and there were a lot of old optical instruments there which we were supposed to take apart and pick out such pieces as we wanted. That's why the method was destructive. And put things together on our own to accomplish the results that he’d suggested. And it was an excellent way of doing things, because it was a good preparation for research.
How did you know what to do? Did you have a laboratory manual for that course?
No, there was no manual, but the things that we were doing were all things that Sabine had told us about in the lectures, if you can call them lectures to five students. He told us, for instance, about Young's experiment, and various things like Fresnel's bi-prism, and the other methods of getting Young's fringes, and he told us a great deal about crystaloptics, and showed us where there were a lot of crystal specimens and things from which we could rig up apparatus for sending light through the crystals, concentrating on them, and then forming an image later and using Nicoll prisms and so on, and saying a lot of very interesting things. He’d tell us in a general way what he'd like to have us — to work up the apparatus to reproduce certain things that he told us about in his talks, and there we were.
Was this a very mathematical course? Could you go as far as Maxwell's equations in the course?
No, we didn't go into Maxwell's equations, because Sabine thought that the elastic solid theory was much easier to understand than Maxwell's equations, and he presented things from the viewpoint of the elastic solid theory admitting that it was not correct, but in his opinion, it was easier to visualize.
How about the theory of sound? Did you have that as an undergraduate?
Very little, only just elementary things like vibrations of strings, air columns, very elementary things, although actually, Sabine was a great authority on the acoustics of auditoriums and was doing a lot of research on them. Somehow they didn't have a course on that. It only came into the general physics course for the first year.
Did you have any other courses in physics as an undergraduate?
Oh, yes. I covered my freshman and sophomore years, and then in the junior year we had a much more advanced course in electricity and magnetism taught by G.W. Pierce, and also more work in theory by B.O. Peirce,  and G.W. Pierce went in very strongly for Maxwell's equations, and wave theory in general. He carried it much further than it had been carried in the light course. Of course, we had more mathematics at that time. And then, I might say that at the same time — well, B.O. Peirce's course was largely electrostatics and the magnetostatics, going into the methods of solving problems, potential theory, and all such, and also a mighty good course. And then I had some very interesting courses in the math department, first in my freshman year, Trig and Analyt under Julian Coolidge, and then sophomore year, Calculus under Osgood, and junior year, Theory of Fourier series and Bessel Functions and Spherical Harmonies, and that sort of thing taught by W.E. Byerly, and Byerly I think was by all odds, the best math teacher that I ever met. He would always start each new subject — say Fourier series or Bessel functions or whatever, start a new subject with some rather simple typical problems and work them out as specific problems, and then say, well, here we're going to generalize on this, and then present the general theory, and with the specific problems, we know what we were talking about in the general theory. It was really an excellent course, that way, and we used his book which was written on that same style.
What kind of a person was Osgood?
Osgood? Well, he was very dignified and methodical. I think a very likeable man. He was sort of unapproachable, you might say, but he certainly did a good job in his courses. His calculus course I remember was very good, and later of course, in theory of functions was very good indeed.
How about Coolidge, Julian Coolidge?
He was a mighty good fellow. He was much more one of the boys than any of the others, and of the other teachers, and — well, he had an amusing way of doing things. I remember the first time that he asked us to use a trig table. He asked us to look up the sine of some angle, and we were puzzling over the thing, the whole class, 30 or so, and he quietly remarked, "An evil generation seeketh out for a sign, but the sign they shall find shall be the sign of the prophet Jonah."
I know his writings are very, very polished. Very distinguished writings.
Oh, yes, yes, he was an excellent teacher.
What kind of material did you use for textbooks in the physics courses?
Well, let's see now. I've forgotten what we used in — we used Hall's book in the high school course. I've forgotten now what we used in that first year course. In the course on light, we had some books that we read as collateral reading, but didn't follow a regular textbook, if I remember rightly.
Was R.W. Wood's book one of those?
I think it was, and then in electricity in that sophomore course, I think it was mostly mimeographed notes that we used written by Peirce himself. In G.W. Pierce's course — I can't just seem to remember what textbooks we used there.
I think he wrote the work on electric oscillations.
Yes, I think so.
Was that written at that time, I wonder?
One version came out about 1908 or 1910, and then I think another came out after World War I.
If it came out in 1908, we might have used it, although I don't remember. If it came out in 1910, that would be after I got through that course. I remember he was a very clear lecturer, very clear, indeed. So were all of those fellows. I think I was very fortunate in having such good teachers.
Well, they certainly form a very distinguished group of American physicists of the day.
They certainly did, yes.
Did you have any courses from Dr. Lyman as an undergraduate?
Let's see. Did he — I think Lyman took over the last part of Sabine's course when Sabine was made dean of the Lawrence Scientific School, if this is what they called it, and I think Lyman took over the last part of that. Then, I don't know, I don't remember exactly, but I think Lyman did some other advanced instruction, but I don't remember very distinctly about that. Then in my senior year, I remember taking a course on engineering mathematics and mechanics under E.V. Huntington, and at the same time, serving as an assistant in the course.
How did you enjoy that?
I enjoyed it very much. I found that very instructive, because Huntington's method was to give a talk to the whole class for one hour, and then have the whole class go up into a drafting room where they could sit at drafting tables and high stools, and then we assistants would go around and help the boys individually with whatever difficulty they got into. And that was very instructive because first off we had to know how to explain our stuff, and second, it gave us a pretty good insight as to what sort of difficulties students got into which would be useful to know later.
This was your first contact with teaching, wasn't it?
Yes, that was in my senior year. And then, we had another course — let's see, a more advanced electrical course there that was mostly laboratory work. That was conducted by G.W. Pierce, too, and we'd go a couple of times during the week to the laboratory — well, with the same sort of guidance that Sabine had given us, find out what you can about this kind of phenomena.
Do you recall whether you performed any experiments on the audion, in that course?
No, the audion had not been invented then, I believe. I'm not quite sure when it was invented, but I'm pretty sure we didn't have it in that course.
What did you use as a detector?
Did you use a carborundum material?
No, most of what was done was with sensitive galvanometers in the electrical measurements course. The whole first half of that course concentrated a good deal on Gauss' methods of measuring the horizontal component of the earth's field, and that was explained to us because in the state of the art of constructing ammeters at that time, the first thing you had to do was to really know a current accurately, was to measure the earth's field and then use a tangent galvanometer, and that was the best you could do.
You didn't get into high frequency oscillations in the course then?
Among all the courses in physics which you took, which one stands out most clearly? Which one made the greatest impression on you?
I'd say Sabine's course on light.
After you took your undergraduate work, what made you decide to go on to graduate school and then into the field of physics?
Well, I'd already gotten pretty well started in it, and I was interested. Lyman assigned me a research job to begin on during my senior year, and so that took a lot of time.
In what field was that?
That was in light. It was on the absorption of light in chlorine and bromine as affected by pressure, essentially a matter of pressure broadening of the various lines of the absorption bands. That was a job that took a lot of time with the kind of equipment we had then, and the kind of thing that we could build up in those days. Of course, we had to make our own chlorine, couldn't buy it in cylinders the way you do now. We'd make it and purify it, and all that, and a lot of things by present standards were awfully crude. But, of course, it was the best you had at that time.
Well, let me ask you a few questions about the organization of the work in the undergraduate school. Did you have any prescribed courses that you had to take, or did you simply select what you wished?
The system was pretty elective. The only thing we really had to take was a freshman course in English, and then we were pretty strongly advised to take a freshman course in medieval History; a course in Government, as it was called then, Political Science it might be now; and, one in Economics; and, I already had French and German pretty thoroughly in high school so that I didn't need to take those; and most everything except that English course was elective. That was in the days of President Eliot who was a strong believer in the elective system.
Why was it that Dr. Lyman suggested your senior thesis? Was this a practice to assign senior theses to all those who were interested in physics? Or did you select him?
Well, I wanted to work in light, and that, of course, was because I had gotten especially interested in it in Sabine's course. Sabine by that time was too busy with his duties as a dean to do any teaching or supervise anything, and he advised me to go to Lyman and see what Lyman would suggest, and so I did. Lyman, of course, was a very excellent experimenter, and he know his theories, too, but he was a very thorough man. I remember very well at the time he announced his discovery of the Lyman Theory, and I talked to the Physical Society right there at Harvard, and it was fairly well along in the meeting and practically every speaker had gone over his 10 minutes by quite a bit, and Lyman, who was a very dignified man, very quiet, stepped up to the lecture table, took out his watch and left it on the table with his manuscript, and read from the manuscript and showed some slides, and then when he got through, he said, "Gentlemen, it has taken me seven minutes to present these data. It took me seven years to collect them."
Seven years of digestion.
Seven years of work, seven years of hard work. After all, he had to have high vacuum to get down to the region that he was interested in, and a much higher vacuum than anybody ever had before or was customary. I remember his pump — well, he had a fore pump, and then his high vacuum pump was a big Archimedes spiral full of mercury, with a return passage, and it was about a foot in diameter, and maybe a foot or a foot and half long, it had about five or six turns, each turn half full of mercury, of course in a helix, and this thing would slowly turn around and the mercury would run around driving the air ahead of it and take out quips, each one consisting of a tube full about 1 1/2 inches thick, and maybe a foot long, and turning slowly about one revolution every two or three seconds, and he had to pump by the whole spectrometer with that, and that took mighty good technique of making things, so that it would be vacuum tight, and then a great deal of patience pumping them out. Then, of course, finding the material for windows as far as he could use any, and then just using a discharge in hydrogen vapor with a narrow slit between it and the spectrometer, trusting that his pump could maintain a better vacuum in the spectrometer than there was in the discharge tube. That was really a heroic job.
Tell me about your own research as a graduate student?
I was not so skillful as an apparatus maker. In fact, I think I was pretty well deserved of my brother's description of me in carpentry, as the world's worst wood butcher. I think my efforts with glass were of no better quality.
Did you have to do your own glass blowing?
No. We would so some of our own glass blowing, but the more difficult pieces were made by a glass blower regularly employed in the laboratory. But, of course, we had to set up our own lens systems and all that, except for a very good spectrophotometer that I had the use of.
How did you select the thesis topic?
Lyman selected it.
What was the title of the thesis topic?
It was, I think, "The Effect of Pressure on the Absorption of Chlorine and Bromine."
This was the senior thesis topic?
That lasted me through four years, beginning in the senior year and winding up as a Ph.D. thesis.
So you had your four years of toll?
Yes. I certainly would not have taken four years about it if I had anything like Lyman's skill as an experimenter, but I didn't.
What kind of a person was he to work for?
Oh, very agreeable, very. He was sort of shy and unapproachable in a way, but very cordial. A very good fellow, and likeable in every way.
If you had some, either experimental or theoretical difficulties, could you go around and hammer them out with him?
Oh, yes, sure. No problem there. By that time I was also getting very much interested in electromagnetic theory, and I was studying more advanced books such as Lorentz', Theory of Electrons, and then in 1913, no, I think it was 1914, I was still around as an instructor then, and B.O. Peirce died. He had been scheduled to give a course in the spring semester or the second half as we called it there, on advanced electromagnetic theory with special reference to the work of Lorentz and Heavyside, and when he died, they asked me to take it over and give the course, and so I did. But I had been doing a lot of studying on it before that.
Had you been doing this work more or less on your own?
More or less on my own, yes.
Who were some of the other graduate students at Harvard at the time you were there?
Well, Francis Wheeler Loomis was one of them, and let's see now — there were two brothers named Allen who went into mathematics. Their names were — I can't seem to think — Fred was one of them, I think, and I can't seem to remember the other one. There was a fellow named Roister, and I don't know whatever became of him. There was Arnold Romberg from Texas, Rice Institute, who was up there and I think he went back to Texas. There weren't very many.
Was Dr. Chaffee a graduate student while you were there?
He got his degree while I was on my way to mine. I've forgotten whether it was one or two or three years ahead of me.
Well, once you obtained your Doctorate in Physics, what was the next stop in your career?
I think I got my Doctorate in 1913, and in the academic year '13 -’14 — well, I think I was mostly studying theory and instructing. I had gone on with teaching assisting under Huntington for some time, and then I got into physics teaching in a freshman course as an assistant, or an instructor, laboratory and problem conference work.
Then you had this third course of B.O. Peirce's?
Yes — that was after he died. I remember that was in the spring of '14. I remember that mostly because people said when the war broke out, that Peirce was mighty lucky to have died before that because he would have been so bitterly disappointed in his German friends going through Belgium. That would have been an awful shock to him. He was really — he was one of those who was sort of nostalgic for Germany, and I guess most of such people were badly shocked by that. Peirce certainly would have been because he had a very sensitive nature and it would have hurt him badly.
What was your next piece of research after the Doctoral thesis?
The next piece of research, I think I was figuring to go on to some more work in light, but then I read the discovery of x-ray reflection by von Laue and the Braggs and the discovery of line spectrum X-rays, and then I figured that the chances were from all I could read about the line spectrum x-rays that they were probably not excited until you got the voltage high enough to excite all of them at once.
What led you to that assumption?
I'm not dead sure right now, but I think it was the fact that the fluorescence measurements that had been taken before seemed to indicate that they got excited all at once, and the measurements of absorption coefficient of these fluorescent rays never showed any change of absorption coefficient with changing the method of excitation, particularly when it was excitation by waves of higher frequency which would not excite much of any line spectrum. I mean it would not excite much of any continuous — I mean you'd got the line spectrum pure, and it would always show the same absorption coefficient, and I figured somehow or other that that must mean to whatever mechanism was involved there, involved all the lines at the same time. And so I'd see with the spectrometer that was so or not.
Had any work in x-rays been done in Harvard before then?
There'd been, first of all, Trowbridge's work, way back. Trowbridge started his work, I think, before 1900, or about that time, and he started this work to find out what voltage was really needed to excite x-rays. He knew that with techniques available at that time, you couldn't get any kind of an accurate measurement with an induction coil, and transformers were not very practical with the x-ray tubes of those days because they would give too much reverse current, and probably smash the tube. So, Trowbridge built his battery of 5040 cells, storage cells, lead type in test tubes, and then found that that was not really enough and built a second half on the same floor, and then found that was not quite enough and duplicated that again above an extra floor in a big attic room where he had it. He had found that you could get x-rays more and more penetrating as you raised the voltage, and he found out what voltages were needed in the general sort of way. Then the subject had been dropped until Duane had a few students, notably Hunt, take up absorption measurements to find out what was the highest frequency that you could get with a given voltage.
What happened as you preceded in your work in x-rays?
What happened is quite a yarn. I had to make an x-ray spectrometer. Of course, we had to very much use the same method in research that we'd been trained in Sabine's course on light. I took an optical spectrometer from the freshman laboratory to mount the crystal on, and then made up a system of lead slits to send some x-rays through the wall into the crystal, and then I made a wooden table that would — had a hole in it for the spectrometer and a round edge, that is, round about a quarter of a circle, and I pasted a paper scale on the edge of that and made it with a radius of 57.3 centimeters so that the paper scale would reach degrees — intensive degrees, and then I had to fix up an arm that would be pivoted on the axis of the spectrometer and would roll around on the table on wheels to carry the ionization chamber and a little electroscope at the end of that. I remember at one time, Sabine came in and looked at it and he saw the way that I had to tilt the electrometer — the goldleaf electroscope, to tilt it just right to give it pretty good sensitivity, was to have the thing mounted on a block of wood with another block of wood under it, tied down with rubberbands and then an ordinary wood screw that I'd turn in under the one edge and tilt the whole business. He remarked about the crudest looking piece of apparatus that he’d ever seen, but it worked.
Let's see, was Trowbridge around then?
Trowbridge had retired. I think he retired when I first entered as a student, but he was around a fair amount until about the time I began my graduate work, and he was still interested in gas discharges, but not doing anything very active with them.
Were you able to got any assistance in the building of this equipment from anybody at all in the department?
Oh, yes, I got assistance from the mechanicians down in the basement. They built an ionization chamber, one of them did, and the adjustment mechanism for width of the lead sled, and things of that sort. But you had to do a good deal of the work yourself, including some machine work, of course, and some glass blowing when there was any. There wasn't on this job.
But you didn't get any assistance from Duane?
No, I didn't get any from Duane.
Once you had the equipment set up, what kind of results did you obtain?
The first thing I did with it was to plot a graph of intensity against diffraction angle to get the spectrum, and found that I had the spectrum lines there all right, and then found much to my astonishment that the spectrum had a high frequency limit, and that the wave lengths, or frequency, was exactly what you could calculate within limits of error of the known value of Planck's constant. It was calculated from the voltage and Planck's constant, and the charge of electron, of course. And that surprised me, because like everybody else that accepted the pulse theory of x-rays, I know that a Fourier Integral analysis would show that there would not be any high frequency limits for a pulse, unless it was of some extremely long, periodic type, but just a single pulse such as they imagined with the cathode ray electron swooping around the nucleus, or doing something else that might be sudden. It would not have any high frequency limit.
Did you communicate your results to anyone there?
I told Duane about it the next day when he came around, and he’d already been having Hunt measure absorption coefficients with thicker and thicker aluminum, and had thought that the results that Hunt had obtained had proved that the spectrum went on more or less fading out, but according to what he considered to be a modified value of Planck constant — a higher value so that it would be a lower frequency that would correspond to a given voltage.
What was the upshot of your communicating?
The upshot of it was that Duane got mad and said that I'd swiped his plan — said that he had been planning to work with a spectrometer himself, though I certainly didn't know that he was planning this, and that I must turn the spectrometer over to him to — I just would have to and let him and Hunt publish the results. And being a rather unsophisticated kid, I did.
So that was the end of that.
That was the end of that, but I went on with the line spectrum work and found that as I'd expected, you had to excite the whole line spectrum at once. This was in the case areas of rhodium, It would be true of any case areas, but rhodium was the metal I used, and to excite the whole series you would have to get the continuous spectrum to run on so that its high frequency limits would be up to the limit of the series, and so then you did begin to get the whole series at once.
Did you have any contact with Planck's quantum theory before this period? Before you began your work on x-rays?
Oh, yes, I had studied it carefully.
Was this on your own? Or did you have courses in them?
I don't think there was any course in it. I think I had to study that on my own. I read Planck's book on heat radiation, and of course, Lorentz' book. Lorentz didn't deal with quantum theory especially, as I remember, but of course, Planck did. It seemed very mysterious that there should be any such thing as quantum theory that seemed to have so little connection with electromagnetic theory, but of course, everybody was mystified by that time.
But they more or less accepted it, didn’t they? Or did they take it with a grain of salt?
A good many of them took it with a grain of salt for a long time, and then some people didn't quite know what was supposed to be run by quantum theory, and what was not. They would say such things as "that God ran electromagnetics on Monday, Wednesday and Friday by wave theory, and the devil ran it on Tuesday, Thursday and Saturday by quantum theory." I've forgotten who made that remark. It was widely quoted.
Well, you carried out the experiments on x-rays, and you published these?
Let's see, this must have been pretty close to the beginning of the War, wasn't it?
This was in 1915, that I announced it at a Physical Society meeting in December 1915, and the publication didn't come out in the Physical Review until 1916. And then, after that, I went on with Harry Clark as a collaborator. He had done a thesis on sound. We got together on this matter of x-rays to see what would happen about excitation of the L series, and there we found that there were three different excitation voltages corresponding to three sub-groups in the L series, now known as L1, L2 and L3 with the levels corresponding, and so on.
You’re teaching as an instructor during all this time?
You had three courses to teach?
I think I gave up the work with Huntington when I got too much on my hands with the freshman physics course, and research. I'd forgotten exactly when I did give it up, but I found that I had to. There was just too much to do.
Well, during the War years, did you remain in the field of physics?
When we got into the War, I got into a job that was — first into the job that was for defense purposes on a magnetic bomb on which I worked during the spring and summer of 1917, and then the navy decided that that was rather impractical, and so, I hunted around and by that time I was due to take on a job with the University of Michigan, and I got out there — really I got out there in the summer of 1917 to work with a ship model tank in connection with this magnetic bomb job. Then when that was over, President Hutchins — was his name Hutchins? It wasn't the Hutchins at Chicago — well, whatever his name was, he got me in touch with Millikan who was starting his science and research division of the Signal Corps, and I went into that first as an aeronautical mechanical engineer, so called on Civil Service, for about nine days when I was waiting for my commission in the Army. And then as a Lieutenant, I was in that for the rest of the War.
What kind of work did you do there?
A variety of things. The first job that Millikan put me on to when I got down there — he was in Washington — first job they put me on to was trying to improve the airplane compasses. That was a thing that had given them a lot of trouble, because of what was known as the northerly returning error. If you were going north and made a turn, your compass would tell you that you were turning the other way. It would do that simply because the compass would bank with the airplane, and then the vertical component of the earth's field would turn it, and that would turn the compass faster than the airplane could turn so it would say you were turning the other way. The Royal Air Force had already found the solution of it that seemed to me as good as anything you could find. Then to make a compass of such long period of oscillation, that the vertical component couldn't turn it faster than the airplane would turn, and that worked out in a fashion. The next thing Millikan put me on to was a very curious job of studying plans that were offered by a man named Rice for a centrifugal gun.
You mean to spin the particles around and then shoot them off?
Well, spin two discs at different speeds, with channels along the discs which could serve as sort of a guide for the ball bearings that were to be fired out, and then fire them off the edge of the disc that way. And Millikan — well, the thing had been turned down by the Air Force, and Millikan told me that this was a simple job, and that he didn't really expect me to do much, but to tell him why it should be turned down. Well, I went and studied Rice's plans, and I decided very soon that Rice was a first-class crank and would never get anywhere, but at the same time he had a good idea. So, I reported that I thought it was a good idea, and should be developed, and I proposed a few modifications of it. Millikan got the Air Force to take an interest in that, and the Air Force promptly christened it the "Rice-Webster gun", which made Rice extremely angry. Rice had his Congressman ask that Millikan should be court-martialled for suggesting such a thing, but Millikan wasn't court-martialled. Actually, the gun did get as far as being set up on one side of a ravine behind the Bureau of Standards with a heavy board fence on the other side of the ravine, and it did smash the board fence all to pieces, so that it showed it would be usable in the trenches. The discs were almost horizontal, so it had a great dispersion in azimuth, but not much in range, and it would have been a deadly weapon against advancing troups in no-man's land, but they didn't get it in production in time. Whether they would have, I don't know. I had got off the job right after recommending that it be pushed ahead, because I had gotten assigned to jobs on instruments in airplanes down at Langley field, and then ultimately in charge of instruments on the tests of the DeHavilland 4, down in Louisiana.
How did you enjoy that work?
Oh, I enjoyed that immensely, especially as that got me in, sort of by the back door, as a flyer. I'm quite sure that I never could pass the physical exam, because I'd got too dizzy in the wheeling chair, but Millikan asked the commanding officer of Gusner Field, Louisiana to please have him give me flight instructions after hours, and he did that. I passed the test as a reserve military aviator without having to take the physical exam, and then got enrolled as a reserve military aviator, still without the physical exam, and then I was doing a lot of flying out of Langley from then on.
Was this pretty straight forward flying that you did?
Yes, straight forward flying. If you can call stunting straight forward. It wasn't all stunting, either, but a large part of it was very straight forward flying. That is to say, speed measurements on speed courses where you'd have to make it just as straight and accurate as you knew how, and that straight forward flying if anything ever was, and likewise dropping dummy bombs with lights on them at night for photographing their trajectory, and that work was under leadership of A.W. Duff and L.B.
Was this Duff of the Duff textbook?
Duff of the Duff textbooks and Duff had — well, I'd gone out— how many of the ideas were Duff's and how many were Sigh's, but Duff had lots of ideas, and so did Sigh. But anyway, they set up two cameras to photograph the trajectories from points quarter of a mile apart. And they had a pair of pendulums that were pulled aside and held by magnets until they were released simultaneously by opening a circuit, and then they would swing synchronously in front of the cameras, and that way would give them — interruptions in the tracks. There was a lot of variety of jobs, largely testing of instruments of all kinds, including speed measurements, and quite a bit of work in more or less on my own spare time, on the stability characteristics of the different airplanes just because I was interested in mathematical theories of stability which had then been developed by Lanchester and Bryan and a few others, and was in pretty good shape.
Did you do what you might call experimental testing of the stability?
Yes, I did quite a lot of it.
What did this involve?
Well, it involved mostly very simple experimenting, just going up in an airplane, and taking my watch out, and then, flying straight and level, and then disturbing the airplane in some way by a sudden motion of the stick and then back to where it was, and then seeing what the airplane would do. Well, it wouldn't do anything startling, as a rule. If you didn't disturb it too badly, there were only very few airplanes that were stable in all modes of motion. There were four known characteristic modes of motion known at that time. Let's see. Is it four? There was the Dutch Roll which had recently gotten famous as a trouble maker in the 707.
Is this the Immilv?
No, no. The Dutch Roll, so called, is a very curious motion consisting very largely of tail wagging with accompanying motion of the wings. If you look out along the right wing, if the tail was wagging to the right, the right wing was going ahead, of course that meant it lifted more than the left wing, so it would go on an upward incline, and then keep on lifting a little more and come back on downward in flying, do a sort of elliptical motion around, and that motion was stable in all of the ships we had. It had to be stable because it was a motion of only a few seconds period and would have been very dangerous if it had not been stable. But it was a difficult motion to get stable without making trouble in one of the other motions which was a slow spiral. If you made the vertical fin big enough for stability in the Dutch Roll, then if you banked the airplane and left it banked, it would start to slip, and this vertical fin would usually be big enough to make the turn further into the direction of the slip and make a slow and gradual inward spiral.
You would lose altitude.
You'd lose altitude slowly, but there was nothing sudden about that motion, and so you never had to worry about it at all. You'd just correct it more because you wanted to stay in your course than because it was likely to be dangerous at all, and the only other motion — let’s see. There were two — that was an exponential motion. There was one other exponential motion, a very quickly damped roll which was very hard to do because you'd have to stop the airplane rolling very quickly and start the tail moving just the other way from the Dutch Roll so that it wouldn't go into that, and to judge this thing damped out very very quickly in a fraction of a second, and then there were two…
Now, let's see. Would this roll be a natural flip over like that?
No, it would be heavily damped on account of the resistance of the wings to any vertical motion, very heavily damped, but it would develop into a Dutch Roll unless you kicked the tail — say, if you're going to roll to the left, you'd kick the tail to the left just a little bit, so that the extra resistance on that left wing wouldn't start you into a Dutch Roll. There would be that combination that you could produce that would be exponentially damped as far as we know without change of character. Then there were two longitudinal motions, very heavily damped — weather vane oscillation of the tail, and a very slow oscillation called the guard, discovered by Lanchester that if it were stable, it would — say, if you know if the airplane up and lifted, the airplane would gradually begin to settle and the tail would lift a little more than the wings and put you into a downward glide. Then that would get you going too fast, and the wings would lift more and bring you up again…
It's kind of a forward fluttering motion?
Not exactly fluttering, because — Lancaster called it because he looked up the Greek word for flight, a flight-like motion. It happened that the Greek word for flight he looked up was one that meant flight from the enemy rather than bird flight. The motion still has that name. That was a very interesting motion, because to get that you had to have an unlifting tail, and practically all of the airplanes that we had, had lifting tails and ran stable in that motion. They would not oscillate. They would just go on up or on down, but slowly, so you never had to worry about that. But those motions in the different airplanes we had — we had 13 different kinds — was a very interesting study.
You did most of this on a jenny?
I did a lot of it on a jenny, and a lot on the De Havilland 4, on the Curtiss R4L, on an imitation Spad that is an American manufactured Spad, and Martin R which was the only ship before the De Havilland 4 that was rather stable against the spiral, and it was near enough unstable in the Dutch Roll so a lot of people were worried about it. You never really had to worry in those days about any of those motions, because if you did fall into a spin it was well known then how to pull out of it. And you'd just do these things high enough up so that you could pull out, if you did fall in a spin.
Did you wear a parachute?
No. none of us had any parachutes in those days. We were expendable. Parachutes appeared immediately after the close of the War for circus jumpers, but they were not issued to the Army.
Was this work of yours on the stability of planes the only work on stability that was being carried out on this side?
The only work on stability that was carried out at Langley. There may have been some other work being carried out at Wright Field. I think very likely there was, because the De Havilland 4 — well, of course that's the British design, slightly modified, as I guess that had been made stable in Britain under the guidance of Lanchester and Bryan and Berto, and we just took it over. But, what they were doing at Wright Field, I'm not sure. I was only there for a short while. However, this work, I found very interesting and I found it very valuable to me later because in 1939, I took charge of the Stanford unit of the civil pilot training program. I found that the things that were being said about airplane stability in the pilot training manual, flight instructors' manual were all completely wrong. They were hayfield airport operators versions — hit or miss guesses. They had nothing very much to do with the facts. They had many things in those books that were wrong, and so in the spring of 1941, it was. In planning for 1940-41 after one year's instructing, I planned to be off in the spring. And I flew East — meanwhile I had looked up a lot about airplane stability as known then. These were later developments which were essentially the same thing as Brown and Berthod had. Then I planned to be off in the spring that year, and soon as the winter quarter was over I took off in my own airplane for the East, and stopped in Washington and went in the office of the Civil Aeronautics Administration and told them that the pilot training manual and the flight instructors' manual were lousy and I wangled the job of revising them, largely on the basis of — well, what I had learned first at Langley and then had practiced up on my own airplane and others in the few years just before the War — the Second War. It was very valuable that way. Then I had the satisfaction of being told later, about two or three years ago, by E.M. Sedour of the Boeing Company that they were still using my revised version of the civil pilot manual as a text on airplane stability.
I notice the propeller up in the wall of the room. I suppose this was from your plane?
That's from Langley. No, that's not from a plane of my own. That came to me because I was told or ordered, technically, to proceed from Langley to Yorktown, the county seat, and to go to the County Courthouse and find out who owned the piece of land that the Army wanted to lease for bombing, this night bombing work. I landed there in the flattest field I could find anywhere near the town, and it turned out to be extremely soft, and after I had been to the Courthouse and got everything, not quite that, when I took off I got way over to the other side of the field. The field was — came right to the edge of the bluff, a couple of hundred fact high overlooking the estuary of the York River, and it was very soft. I took off toward the bluff, and the machine was just on the edge of beginning to lift by the time I got to the bluff. I knew she was so close to the edge of it, that all I had to do was push the stick forward and nose down so that it would take off a little on the lugs and drift easily until she could got a little extra speed and be ready to stay up and so I did. But in the meantime, I took off the top of a cherry tree below the bluff and took home a lot of cherry branches, all over the landing gear, and nicked the propeller. So they gave me the propeller.
I hope it was in the springtime.
I guess it was. Now let's see. When was that? In the spring of 1918, I was on the job in Louisiana then, and I really got back to Langley Field that summer. It might have been that summer, because that was about the time that Duff and Sigh were starting this bombing job.
You've got some pretty good sized nicks in there.
Along with some cracks, too, I see.
The cracks — I don't know for sure how much they were there then, but I know I did stop at the next field that looked reasonable to land in which happened to be away from town a ways, flying in as easy as I could until I got there. Then I put blocks in front of the wheels and revved her up at full speed for five minutes. I found the propeller didn't fall apart, fly apart, and took off again for Langley. How much of the cracks were in it right then, I'm not sure.
They seem to start from that point.
Yes. Well, it was one of those little adventures that is more fun to look back on than at the moment.
I wonder if we could go back a little bit to the work that you did with Dr. Millikan? What was the name of the organization for which you worked?
Science and Research Division of the Signal Corps.
And he was the head of that?
Then you hold a position under him at the end as Captain, was it?
And he was a Colonel?
He was a Lt. Colonel.
What kind of a man do you think Millikan was?
I always thought he was an awfully good fellow.
What kind of an administrator was he?
Well, of course, I was pretty well low down in the organization. I didn't get too much in touch with that, but in between us, there were two people, Major Mendenhall who was also a physicist of Wisconsin, I believe, and Thomas B. Culp who was in charge of the branch office of Langley Field. I was really, well — we didn't have a very tight organization. We didn't have to go right down the line with orders at any time. I remember Mendenhall one time getting a letter from the Chief Signal Officer or somebody saying that each officer will direct his men as to when to wear overshoes. Mendenhall put on his most impressive sounding voice and said, "I hereby direct you to wear your overshoes just when you damned please." That was the sort of organization it was. A good friendly group with no unnecessary bossing around, or anything.
After the War, did you return to Harvard, or did you strike out on your own?
No, I didn't return to Harvard. I got a job at MIT. I had been going back to Michigan, but my brother got killed in France, and I wanted to be near my parents. So, I scared up a job at MIT, and was there for — well, from January 1919 to September 1920, and then I came out here.
What were the circumstances leading to your coming out here in the West?
The circumstances were that Professor Sanford had retired, and Professor Rogers was getting pretty well along, so that they wanted to get a younger man to be head of the department and they tried to get Karl Compton to take the job. He looked at it and he decided he wouldn't. I think they tried Mendenhall, too. Then they tried me and President Bulbar came to MIT to talk with me. He was on a trip East anyway, and I'd just been in the hospital with pneumonia and had just got out and was thoroughly fed up with the climate of that neighborhood. He offered me a chance to come out here and take a job here — to come out and look at it first. I got out here and took one look and decided I'm coming here.
Did you come out here as head of the department then?
How big was the department at that time?
Oh, about five or six of us. Very small department.
What were some of the main problems in building up the department here at Stanford?
Well, the few men who were here were pretty nearly all we could get here at first, or that we had the cash for. So there weren't any problems for a long time. And, one of our graduate students at that time was George Harrison, and of course we hung right on to him just as thoroughly as we could, as long as we could until MIT gave him a much better job than we could ever give him at that time here. Then I got Paul Kirkpatrick to come here and pretty soon after that Felix Bloch, and well, I didn't feel I was much of an administrator, but I didn't feel that there was a terrible lot of administrating to do. It seemed as though the thing I had to do was to devote my attention to research and teaching. I was still very much interested in teaching, and had been right along, of course. So, most of my work was research and teaching.
What were some of the principal problems that you worked on after you came out to Stanford, in research?
I was interested to some extent in the theory of continuous X-ray spectrum, and trying to got some experimental data that would check on some of the theories that had been developed. Also, I suggested to P.A. Ross who was out one active — really one active research man, besides myself, in the department at that time, that it might be a good idea to see about the excitation of the M series x-rays. There are five excitation potentials there, five set groups, which he found. He had to develop a good vacuum spectrometer for that, and for any of this work we were interested in intensities of x-rays as a function of voltage, essentially what they now call cross sections of the function of energy of the cathode ray particles, that both for continuous and line spectra, and so one of the first things we did, Ross and I together, was to develop a really good high voltage outfit, D.C., where you could keep the voltage very steady and know just what you had for your measurements. That was a bit of a problem. We did have what seemed at that time to be a vast amount of money, namely three whole thousand dollars. That seemed like a pile of money. Then, even so though, we made a choke coils for our high voltage filter out of the secondaries of old induction coils discarded by the medicos turned in by some of the people up in San Francisco on purchases of modern medical x-ray equipment. And we wanted to furnish them with cores that would not saturate too easily with D.C. so they'd still act as filters with A.C. So, we went out and got a whole lot of elevator cables, steel cables and cut that into four foot lengths and put that in as coils. And the condensers we used — they were quarter sections of great big plate glass discs that had been used by medicos in static machines for x-ray work. A good deal of the equipment was actually collected out of the university junkpile. A good deal of our metal came from there, in spite of the $3000.
Where did you get the $3000 from? The University?
Yes. When I first got out — well, there had been one year since Sanford retired. Sanford had been very economically minded and never wanted to spend money unnecessarily, with the result that the department never had anything in the way of cash. Let me show you the shop equipment that the department had. The shop equipment of the department was this — this is the whole damned shop equipment of the Stanford physics department.
Just a pair of pliers?
Five cent store pliers at that, more or less bent out of shape. Sanford, as I said, had been very economical, then Rogers had been acting head for a year. He and Sanford never got along very well together, and Rogers promptly spent all the money that Sanford had saved over decades and ran the department about $2000 in the hole. As soon as I got there, I told Webber we need some cash, we're in the hole. He appropriated $3000. But it was a long time before we had much more than that.
After the investigations on the M series, what did you turn to next?
About that time Duane was beginning to come up with his very peculiar effect, and so we did as good as an investigating of them and couldn't reproduce any of them. Then Compton discovered the Compton effect, and Ross was a very bright man. He had a lot of ideas. He immediately thought, well, here, Compton's theory says there should be a given wave length shift no matter what the initial wave length was. And so, that shift was about a quarter of — now, hold on — not a quarter of an angstrom either. I guess the Compton shift is — roughly about 200th of an angstrom — anyway whatever it was, Ross figured you ought to be able to get it with an interferometer in light. So, we tried that on the green line of mercury and observed no shift whatever. And then, he said, now what the heck, and went back and plotted the spectrum of scattered rays which are not an easy thing to do, so very weak, and discovered that you had along with the Compton shifted line, you had an unshifted line. He discovered that. Then that started him off on quite a long line of investigation of the Compton effect. Then, while that was going on, Duane had been announcing those other things, and they looked awfully peculiar, but I tried out two or three of them.
What were these other things that you tried out?
Well, let's see. One thing, as I recall it, he said that if you reflected x-rays from a crystal of potassium bromide using continuous spectrum rays, the bromine line should show up in the spectrum. Well, it didn't. There were two or three other things like that. I've forgotten now just what they all were, but I tried several of them. They're rather simple experiments. They didn't show at all, and I thought well, there's no use picking a fight over this thing. These things aren't worth it. About that time, Duane came out with an idea that what Compton had observed was not really the shift that Compton had predicted, but a scattering effect due to scattering of the rays in the wooden box containing the x-ray tube. Something I think analogous to the Raman effect, if I remember rightly, but I don't remember too well. He wrote a letter to Ross — Ross had announced his discovery of the unshifted line — Duane was interested. He asked Ross if he had used an x-ray tube in a wooden box with lead over it. Sure enough, Ross had. It was a natural thing to do. In fact, the wooden box had a couple of handles in each end, pieces of tube, and Ross being a son of a minister called that the "arc of the covenant." So, just to check up on that then Ross and I went out to the university junkpile and found big pieces of heavy cast iron pipes and we drove some holes in that and put lead ends on it, and using voltages of not high enough to make rays that would penetrate the pipe.
Ross did a scattering job inside that and found the Compton shift again. By that time, a controversy was on, more or less. Then, we got Coolidge to make up a special tungsten target tube; it was a very narrow glass tube, with a tungsten target, and a cathode and the rest of it, so we could get a scattering object right near the target, and investigate the scattering of tungsten line spectrum rays. Sure enough, it came out according to Compton's theory with the unshifted line, too, of course. It was then — well, then Ross went East to report that at the December meeting in 1925. That was it. That was after the Braggs' and some of the other Britishers, Darwin was one, I believe, had asked me at Toronto in the summertime what I thought about Duane's effects, and I said I didn't think much of them. Well then, Ross went East to report this thing, and Duane didn't say anything against it, and somebody asked — I guess Becker. I've forgotten his first name now. He'd been here for the summer. J.A. Becker, he asked Duane what about this? What are you finding now? And Duane said he wasn't finding anything now different from the Compton effect. Ross told me that Becker kept cross-examining him and quizzing him on the thing until the whole business got extremely disagreeable, and Ross didn't take much part in it. He just reported what we had found, and that was that. And then apparently, there was no explanation for this thing. Well, then months later I heard the explanation.
All these effects had been found by a group. Duane, being over at the medical school most of the time, there's a group of students, including Allison and a Miss Armstrong, and a follow named Stifler, somebody whose name begins with C, I've forgotten, they had been working together — apparently Duane had been over at the medical school all the time — oh, George Clark, yes. Not the Clark that had worked with me; that was Harry Clark. Clark had taken all the readings in the electrometer. The others had simply made the spectrometer settings and done little odd jobs, and Clark got a job as head of the chemistry department at the University of Illinois, and left in September, and from that moment on not a one of these effects appeared. Clark had found just what Duane predicted, or said he found it, and Duane, poor devil, had been taken in by it. Hadn't checked it himself. Hadn't made any readings of the spectrometer himself, and neither did any of the others, and the effects all disappeared when Clark left. Poor old Duane just simply pined away and died within a few months after that.
Duane wasn't really an incompetent experimenter?
No, he was not an incompetent experimenter. His chief fault was that he had not done any of the experiments himself.
He was a poor administrator.
He was a poor administrator. He never checked up. He never bothered to read the electrometer himself. The things that he had predicted had been found apparently, and there they were. [Interruption in sound]…I think it was. Yes, Compton told me afterwards that after this blow up, Allison came around to him pretty much on his hands and knees begging for a chance to redeem himself. Compton gave him a job, and he's done well ever since.
He certainly is an outstanding man.
So, apparently, that's where the thing rested. That is, nobody ever went after Clark about it, apparently.
He was in another field anyway.
He was in chemistry by that time, yes.
Did you do work in any other area? Or did any of your students work in any other area?
What I really wanted to do was to continue the study of theories of x-ray emission, and everything that went with it. I realized pretty soon that the only way to really get at anything reliable in the experimental end of it, was to use extremely thin targets, so thin that the cathode rays would hardly lose any speed in going through the target. Because if you used a thick target and started in with a known speed it was all right you had D.C. to propel them, but then of course, they'd lose speed on the way in and you have a sort of a mixture of things. I wanted to develop — I wanted to work toward the thin target business, and among other things I did first though was to try and find out what fraction of the rays, line spectrum rays would be produced by direct ionization by cathode rays, and what fraction by fluorescence through the continuous spectrum. I did quite a bit of work on that, using silver targets with thin sheets of cadmium over them, because then you would stop the cathode rays in the cadmium and get cadmium lines, and then most of the continuous spectrum would go back into the silver to produce silver lines. So you could sort them out more or less that way. And I did quite a bit of work on that and some of the students here, Foster, and Hansen, were interested in those things and took part in them. Then when we finally got some of those questions settled, then Hansen and Duveanek and Clark and I, that is, Harry Clark again, went out to the job of working with really thin targets.
We used a block of beryllium cooled by oil inside and thin target with very thin layers of silver were put on by vacuum evaporation. That technique worked pretty well up to about 100,000 volts and beyond that you had to use silver leaf because you got too much trouble with the rays from the beryllium if you allowed the higher voltage cathode rays to go in. We did a lot of work on that for years and years. It was a long time consuming job. Another Clark, John C., did a very good measurement of the absolute intensity. Of course we were only working with relative intensities, relative one voltage to another. He did a good job on the absolute intensity of thick target rays from silver and we put that all together and got a good clean-cut idea of the laws of excitation of those things and conveyed it with the various theories that were up at that time. After that — let's see — Hansen did some other work. Hansen went East after he got his degree at MIT, and then he came back — oh, he and Stoddard did more of this direct and indirect excitation with other combinations of metals. With the aid of another student, Leonard Parkman — I got to work on the rays from nickel. They being much softer and more easily excited, a different part of the spectrum, to see how much of the deviation from theory in the silver rays might be due to the relativistic nature of the electrons that we were using. Using lower voltages with nickel we could get away from that. We were on that pretty long a way with it, when the Varian brothers invented the klystron, and we knew the war was coming, so we figured, here, this klystrom is a thing that is needed for the war. The Varians asked me to come in on that to develop the mathematical side of it, and so I jumped out of x-rays for that. Pockman went on for a while with it, and got the thing fairly well finished up.
I wonder since you brought up the subject of the Varian brothers and the klystron, if you'd want to tell us something about the steps leading to the invention of the klystron.
As I recall it, the steps were primarily these: Sig Varian was a Pan American captain based in Mexico City, and his wife was the daughter of the British Consul, and she did an awful lot of bragging on the part of Germans in Mexico City about what Hitler was going to do to England with his airplanes, and she asked Sig, “How about it? Could airplanes do this?” And Sig said they probably could. She stirred him up to think that something ought to be done about this, and so he called in his brother Russell, and Russell had been working for Philo Farnsworth in Philadelphia. He came West here — I think for a while he was interested also in trying to make diffraction gratings such as Wood had made, but then pretty soon this possibility of doing something about this use of very high frequency microwave for radar became so important in his mind as well as in Sig's, that they both came up to Stanford to work with Bill Hansen, because Bill had invented the cavity resonator, then known as the rhumbatron. They came up for that purpose, chucked their jobs not knowing whether they could invent any such thing or not. Then Russell always had a tremendous lot of ideas, and he'd fire them off at Bill one after another and Bill would knock them to pieces until he came up with this idea of electron bunching, and that seemed good. So then he designed — or he and Sig and Bill together maybe designed the first klystron, and Sig made it in the shop, and it worked.
Well, how did Hansen get into the field of microwaves?
He had wanted for a long time to make up a device that would accelerate electrons to much higher energies than he and I had used on this thin target work which was up to 200 kilovolts. He figured the way to do it was to — he figured on various schemes, but finally he came up with the idea that the best way to do it was with a cavity resonator. He'd been interested in electromagnetic theory. He invented a method of treating the wave equation in spherical coordinates that was much more satisfactory than anything that we had before. It showed out in some detail in Stratton's book now and credited to Hansen. This involved the use of some functions that would ordinarily, for radio purposes, be combined with functions that would decrease with increasing radius, but also it could be worked the other way with increasing functions, and some of those increasing ones suggested to Bill that you could make a cavity to contain these fields and it ought to resonate and be a far better resonator of a high frequency than anything you could make up with coils and condensers. So he worked on the theory of that and he figured out that if you could make a good big cavity and run it up — get these waves going in it and run it up to good strong fields you could accelerate electrons with them and probably get more out of it than you could out of our 200,000 volt outfit. He was interested in cavity resonators from that viewpoint.
From the theoretical viewpoint that he came to the idea of building a cavity of the kind which would accelerate electrons — it was not on an experimental basis that he …?
No, well, he got it on a theoretical basis just studying the mathematics of waves. He figured you could get the waves to resonate inside the spherical cavity, and he didn't know just at first what else you could do besides the spherical cavity, and his first idea — well, I guess he developed — he had studied these functions when he was back at MIT on his own, and developed the theory of them, and then his first idea when he came back was to use a spherical cavity. He asked me what I thought of that, and I thought it over a bit, quite a bit, and I'd run across the idea that a spherical cavity wouldn't be as good as what you really ought to have because if you had the fundamental waves, a system in which you say you have a sphere with a vertical electric field oscillating in the middle of it, the frequency would be such that an electron couldn't get all the way through on one half cycle. It would get decelerated before it got through, and something ought to be done with a cylindrical cavity with less height than width so as to get the electrons through that way better. Bill saw that that was so and he worked up the corresponding theory of Bessel functions for that purpose. Sure enough you could use a cylindrical cavity perfectly well. So then he wanted to use that to accelerate electrons to high speeds. Well, it was that that Russell Varian had heard of and he figured that's one use of it maybe, but also if it's a really good resonator with a high Q then it would be much better for microwaves where losses got bigger than any other kind of a resonator. That was the kind of thing that he thought he wanted to use. He figured he would invent some kind of a microwave generator that would be almost sure to use one of Hansen's resonators.
What was the basis of the microwave technique at that time? Was this very much in the experimental stage? I mean, was it still being worked out?
There weren't any microwave techniques at that time as far as we knew. I think the magnetron was being invented about the same time in England, but that was a highly classified secret.
How about the work of Southworth? Is that well known? At the Bell Telephone Lab?
Southworth — I know he was doing a lot of radio work, but I don't know whether he was doing any microwave work at that time. The big problem as Russell Varian saw it, and quite correctly, was that if you took an ordinary three electrode tube or four or five electrodes for that matter, and tried to use it for extremely high frequencies, the transit time of the electrons from cathode to anode was too large a fraction of the half cycle. That was what made tubes of the ordinary types become inefficient as you got to higher and higher frequencies. And then at the same time, resonant circuits were becoming inefficient because you had to make them small and the ratio of L over R was going down and — or at least L over R omega, was going down fast — and so you were pretty much limited to waves of a meter or more. And then this Hansen rhumbatron offered at least a solution of the problem of the efficiency of the resonator, and then the question was what to do with transit time. Well, that's what had him stumped for quite a while until Russell came along with this idea that you could use two of this rhumbatron to increase and decrease the speeds rather slightly, and then allow the electrons to drift in a field free space so that the faster ones would overtake slower ones and they'd collect in bunches and then let them go through the other resonator and if the oscillations of that were timed right, they would go through against the electric field and give up their energy. That was the real kingpin idea of the whole lot, that and the resonator, because there instead of being stymied by transit time he was using transit time. So there we were. Well, then the question was just how much can you get out of this? How much energy can you get into these bunches, and what are the best conditions for it, and how will you control your phases, and so forth? That's where they asked me in on it to try and figure that out. I don't know quite why they did, because Hansen could have figured it out perfectly well, but anyway they did, and so I thought here is a chance to get in on something useful in the war work for what was obviously coming. And so that's how I got into it.
What was the relation of Hansen to Stanford at that time?
He was an assistant professor.
He was an assistant professor.
He may have been an associate professor by that time.
Were the Varian brothers in the department officially?
They were in as research associates, if I remember rightly.
And Hansen had obtained funds for these men to work with him?
Well, he'd obtained … First it just sort of a share of the department funds and then he got to — after Russell had invented the klystron, then Warburg gave them a grant I think $1000 to develop it. Then about that time, Willis of the Sperry Gyroscope showed up and through him we got Sperry interested and then of course there was any large quantity of money.
What happened after some of the practical details of the klystron had been worked out, who had the basic patent on that?
The basic patents were held by the Varian brothers. I think Bill (Hansen) had a basic patent on the rhumbatron, and I got the patent on a modification of the rhumbatron from the cylindrical form to make it more or less a doughnut shape with grids across the hole in the doughnut, punched the ends in, because that would get your distance around in the metal shorter and get the grids nearer together, and that would save losses of course, and get your electrons through between the grids faster. Then beyond that a lot of other things were invented eventually, but the basic patents were really the Varian brothers and Hansen.
And these were their private property? They didn't sell them, did they?
No, they assigned them to the university. They did that because the only way that Sperry would agree to finance the thing was the way any industrial concern would. To do it only on condition that they held the patents. They agreed to pay royalties to the university and the Varian brothers and Hansen, and Hansen offered me a share of it, but another condition that the Sperry Company had put was that I was to come in as an administrator on the thing, and I figured that it would be a case of divided interests if I was to hold a patent on any part of it or be receiving royalties, so I didn't go in on that. But I agreed to work on the thing for two years, and then it was pretty close to the time that the two years were up when I got some trouble with my eyes from exposure to microwaves, and at the same time the business of civil pilot training program was coming up. And so, I figured here we've got all kinds of talent in this thing, and there is now no reason why I should stay in it any longer, and I should be on this pilot training business because I was the only member of the faculty that flew. That's how I got over to that.
But Hansen assigned the patent right to the klystron to the university.
Hansen and the Varian brothers.
Did the Sperry Gyroscope have any control over those patents?
They — I'm not dead sure of all the details, but I know that Sperry was to — well, their lawyers were to take out all the patents — all the new patents that had to be taken out. In fact, their lawyers handled the whole patent business on the initial ones, too, and they were to pay, I think the whole of the royalties, 45% of the lot, that they did pay at least to the university, 45% to the Varian brothers, and 10% to Hansen.
Did the introduction of these quite large financial assets in the field of physics affect the physics department?
Oh, yes. Sure. Introduction of a lot of financial assets and employees of Sperry who were not part of Stanford University at all, but were sort of injected into the laboratory and didn't feel a part of it at all. They were out for what they could get, and I think it's a pretty good rule that anytime you get a large amount of money coming in, or a very promising looking patent, you attract a lot of damned undesirable characters, and I'd say a lot of those fellows were.
What did they try to do?
They tried to get control of the laboratory for one thing, and Willis called the whole outfit together for meetings that he wanted to talk things over and even called on the mechanicians and everybody else, and then he demanded that I turn over half the building to him. Well, I told him to go straight to hell, and I wouldn't consider doing such a thing. And then they moved out and established their own laboratory in San Carlos.
Who was Willis?
He was an employee of Sperry. He'd been employed on a variety of jobs in Sperry, and I'm not sure what they all were, but at the time he showed up he was on a job of studying the vibrations of airplanes, traveling around the country with two CAA inspectors, or engineers, in, I think a DC3, studying vibrations under various weather conditions, and what not. Then they dropped into Oakland Airport — that was the local CAA headquarters in those days for this whole region, and one of the CAA men in the office there was a good friend of Sig Varian's from old times, and he knew what Sig was doing, and he told these other CAA people who told Willis, I guess, and they — well, it happened one of these CAA men, one of the ones that was traveling around, had got an idea for a blind landing system which he considered very good. Well, he got sort of a garbled account of it, about third hand, and thought we had a blind landing system developed up here. So the two CAA men and Willis came down here, by appointment, and we had a meeting in my office with the Varian brothers and Hansen and these fellows, and this CAA inventor was obviously mad, and he said, "I understand you fellows have a blind landing system. What about it?” Something like that. I said, “No, we haven't got a blind landing system, but we have a good source of short wave power that might be used in one.” And by cripes, he changed instantly, just about fell on my neck, and said that that was the one thing missing in his blind landing system and if we could just get together on it, we had the world by the tail.
I thought his blind landing system was a pretty darned good one, too, but it never got adopted. I don't know now quite why not, but the idea was, suppose this is a runway and you're coming in to make a landing on it, and you want to land right here, if you had a pair of posts here with lights on them and a light on the ground there, you could tell from those three lights just where you were in relation to the glide path. Well, what he proposed to do, was to rig up a short wave transmitter that would somehow or other transmit signals through a cathode ray tube in the cockpit of the airplane in the instrument board, and give you three spots that would be in the same relation to an imaginary three lights, and all you'd have to do was to make believe that there were three lights placed that way and fly in right in on it. And I don't know why that wouldn't have been a darn good scheme. But somehow they never did it. They used other schemes instead. But, anyway, that was his idea, and all he thought he needed was a source of short wave power. He knew it would have to be short wave power to be able to beam it out accurately.
You left the work on the klystron to get into other work and this was the civilian pilot training program. Did you do that throughout the rest of the war?
No, I did that for a couple of years until the war broke out, and then of course the whole thing stopped. And then I was on a rather no-account piece of research, an unimportant one that the — oh, what do they call that — that organization they had then? — was it OSRD, I think it was, it was four letters. They handed us this problem as one that we might work on. It didn't look very important, and then when we got into the War, I tried to get into the Navy, but they seemed to think I was too old, and so then I — oh, NRDC that was the organization, the National Research and Development Corporation, was it? Anyway, I did a little work for them for a while, and then went into the employ of the Army and wound up pretty soon at Aberdeen Proving Grounds on rockets.
What kind of research did you do on rockets?
A variety of things. They — the Army had two runs of rocket work going, and the Navy had one at Cal Tech. The Army rocket work was more or less controlled by a Colonel Skinner. I think his initials were B.F. but I've forgotten now for sure. Well, he had been working as sort of a lone wolf for eight or ten years before the War on very little money, because the Army couldn't see any point to rockets, and he'd been practically working alone without much communication with anybody else. He had some pretty fixed ideas as to what ought to be done, and about all we could do at first was to try and make rockets along Skinner's lines rather better than they were, make them more reliable and less likely to blow up. That's the big problem in rockets in those days to make them so that they wouldn't blow up in hot weather or quit in cold weather. The Army had a requirement, I think it read that they were supposed to operate anywhere from 60 below to 160 above, but we very soon convinced them that this was a little unreasonable. 40 below to 140 above would be plenty good enough. So we were working along those lines and very largely trying to improve the reliability of those 4 1/2 inch rockets, at first, and then the bazooka rocket began to get into trouble. They — the bazooka rocket had been developed independently of Skinner by a Lt. Ewell who was working at the Naval Powder Factory at the Potomac River down below Washington, on the East side of the river, and he had sometime early in the autumn of ‘42, I think it was, he had put on a demonstration for some of the brass with the bazooka rocket.
Oh, he was working more or less along the lines that had first been suggested by Clarence N. Hickman of Bell Lab. Hickman had worked on the bazooka problem in World War I, and had blown off three fingers just about the end of the War, and the thing hadn't got anywhere. I'm not sure where it would have ended, except that in the meantime somebody else had invented the shaped charge. Hickman was still on the gun coming from Bell Lab once or twice a week, and they had improved powders, propellants that is, and shaped charges so that the whole thing was much improved. Ewell put on a demonstration at the Naval Powder Factory, and the brass promptly adopted it — they said you go into this production right now in a big way. Ewell told them this thing didn't have all the bugs out of it yet. They said, "We don't give a damn if it doesn't, you produce it, right now." Well, orders are orders. So Ewell produced it, and it stopped the Germans at Caserine Gap in North Africa. Then there were two troubles with it, one that it was liable to tumble in the air and not hit straight. and the other that developed in the southwestern camps in the following spring that the rocket — the propellant powder was liable to blow up right alongside of the man's head, and smash his head in. And so, we'd begun to work on this matter of trying to stabilize the thing better to make it fire straighter, and then orders came through all of a sudden to do something about this blowing up situation.
So, we all got to work on that. And I thought of one idea that perhaps one thing to do in a desperate emergency, would be simply to go into the drill and remount the throat of the nozzle so as to let down the pressure a little bit. You might lose some range, but at least you wouldn't blow people's heads in. So I had them treat a bunch of twenty rockets that way and put them in a hot room overnight and took them out in the morning, fired them by remote control and a larger fraction of them blow up than had ever blown up before. Well, then they knew the trouble was not in the throat of the rocket. What was producing the high pressure might be somewhere else. And then we all took another look at it, we all being about four or five of us there in the rocket branch, and sure enough the trouble was that the powder grains were held from going down into the nozzle by sort of a stove grid and that stove grid was taking too much room and blocking the passage of the gas more than the nozzle was, so when I reamed out the nozzles, the stove grid had all the more pressure difference on them and caved in all the more and let the grains right down into the nozzle. So then, N. Christensen who was chief of the branch, and one other follow who's name I can't think of at the moment, promptly thought up another mighty good idea. The thing to do was to make a grid in the form of sort of a cartwheel with many spokes and plenty of space between them and a hub in the middle that would project forward a little bit and hold the powder grains further away from the spokes and hold them only by the edges of the powder grains and not the hole in the middle of them, and thereby not impede the flow very much, and so we had some of those things made up. We put them in a hot box overnight, at 140 degrees, and in the morning a bunch of us got in there and took the rockets apart and took out of the stove grid things that were in there and snipped off something like 3/8ths of an inch of each powder grain and put in the cartwheel and put them back together and handed them out by the boxful, and the boys outside made them go bang, bang, bang all day and not a one of them blew up. And so, that was it.
Were there any other projects you worked on at Aberdeen?
Yes, there were some spin stabilized rockets, the early ones that had been spin stabilized, and it occurred to somebody that it might be a good idea to try the effect of spin stabilization. So, we worked on that. One fellow by the name of Walker, I think his first name was George, designed a spin stabilized rocket for firing from the ground, and I designed one for firing forward from an airplane. That required a part that spinned, because you had a higher velocity the minute you got out of the launcher, and then we did various other projects. There was one that had to do with the rocket that was ostensibly able to generate smoke screens, but of course chemical warfare was not allowed. But somebody in Washington told us to develop this thing, and so we did this with fuming sulphuric acid which would develop a smoke screen. Well, if it happened to land on somebody that wasn't chemical warfare because it had the intention of a smoke screen which was sort of the wrong kind of smoke screen, but, that was…
Kind of gruesome.
Kind of gruesome, but then after all someone was right, you know there were a few other projects like that that were worked on.
After the War, did you return to Stanford to teach?
You remained at Stanford until you retired?
Yes. Paul Kirkpatrick had become head of the department when I left for the War, and he kept the job after I got back. Most of my work from then on was teaching. I didn't do an awful lot of research.
I wonder if you would want to say a few words about what you think makes a good teacher?
I don't know that I have any definite formulated philosophy of the thing, but one thing I would say was absolutely essential was that if you're going to be a good teacher, you've got to be willing to answer students' questions at any time, in a lecture or otherwise, and you'd better know your stuff so that you can answer them pretty well. And, if you don't know the answer to the question, you've got to be absolutely frank about saying you don't. Those are some of the essential points, I would say. Then, of course, you want to put on — you want to make clear explanations of things. You want to put on good experimental demonstrations as far as that can be done which means mostly in the elementary courses. I think it's absolutely essential to have clear explanations of each subject that you're going to talk about ready for use, and then not insist on talking about them in that order. In the last few years at Stanford, I was teaching engineering mechanics every autumn, teaching it to the class for engineers, and I had three sections, the room only held 130, so we had to have three lecture sections, and the three lectures in the day were never much alike. They covered the same general subject matter, and I used the same experiments, but very rarely in the same order, mostly because anytime a student had a question, I always encouraged him to — anytime they had a question to just hold up their hands, and I'd ask them what it was regardless of what they might be interrupting, and I'd answer the question.
It was practically always pretty much to the point. The students who asked the questions were mostly the better half of the class, not the worst, and very often the things they asked about were ones that I had not planned to cover that day, but that didn't make any particular difference, because if I didn't cover something that day. I could cover it the next day, and it was more to the point, I thought to answer a student's question promptly, when he brings it up, because it's not only for that student but for the rest of the class which always pays a lot more attention to an answer to a student's question than they do to anything that you bring up on your own initiative. I've noticed over the years that that was always so and therefore personally I thought answering the questions was very important. And of course very often in a subject like that especially, if a question is to the point it may very well be on something that you should figure to bring in later on in the lecture. You can answer it, and then say, here, just to prove this thing, here's a place of apparatus that I was going to use later on in this lecture. Let's put it on now and demonstrate this thing, and that always went over big. I thought it was very important to be quite ready to break the order any time that way, and also to have good simple experiments that didn't look like elaborate showpieces, and didn't require much explanation of details, and in a subject like engineering mechanics anyway, the more closely they could be tagged to something practical, the better.
For instance, one of the things I had was in connection with the theory of the crane, and such a thing as the brace that you see from a telegraph pole out horizontally across the sidewalk. A wire coming down to the end of it, and another one going down to a dead man in the ground — the thing you wouldn't notice about that is that if that brace were made with an iron pipe or a steel pipe, it has the screw fitting on the end of it, an oblong screw fitting with two holes in it and bolts into the post, and the bolts were always left a 1/4 inch loose, so the thing can hinge up and down. Very important indeed, because otherwise the slightest give in anything in your telephone pole or in the dead man or anything else would just bust the thing off. It had to be able to act like a hinge. So I rigged that thing up in the lecture room and demonstrated it, and showed them here is the kind of thing you fellows have got to remember when you come to practical engineering work. You remember if you're going to treat the thing as a hinge, be sure that it's hinge or at least it's limber enough to act like one, and so on. Things like that. Little practical details that certainly livened the thing up for any engineering student, and I think for a physics student, too.
What has been your philosophy of research?
Well, philosophy of research has been mostly to find out — to think up what question is going to be more interesting, most significant as a matter of general principle, and then see what you can do to get an answer to it.
Once you have that question that looks as if it is of interest, how do you go about trying to find an answer to this question? Do you sit down? Do you look up whatever anybody else has done? Do you go into the laboratory and try to fix up an experiment? Do you repeat what others have done?
You have to do a lot of looking up, of course, or otherwise you might just be repeating what somebody else has done. There's no use in that. At the same time, I think very often it pays to do quite a bit of thinking about it first you yourself and consider yourself what you think the answer is before you look at too much other work, because otherwise if there is a mistake that has been made rather readily and you read about it, read a convincing sounding account of it, you're liable to think well, that's all right, sure, and not see that it was a mistake. It pays to think about pretty much at first before you do too much reading, and —
— and develop your own opinions on the subject.
Develop your own opinions on the subjects, more or less, first, and then work up enough to make sure that you're not simply repeating what somebody also has already done. And then, if it's a question of theory, well then, see what you can do about theorizing it, mathematical work, and so on, or if it's something that has to be settled experimentally, well then, see how you can design an apparatus that will settle it. Not a very elaborate philosophy at all, but I think the basic idea is what is needed to be done.
In your own work, who do you feel has been the greatest influence on your work?
I would say some of these early teachers, right back to Greenhall, my mother at first for getting me interested in astronomy and chemistry. Then maybe Greenhall, Sabine, Peirce, and Pierce, Lyman, those fellows — they were an awful good bunch of men. You'd have a hard time finding anybody that could be much better. Then of course I did read a good deal too, well people like Lorentz, Poincare and of course the Braggs — people who had done valuable work and anything you could read about that was good. Planck, of course, and I think I was influenced more by teachers and later by people whose work I read who were off in the distance that way. And of course, Pat Ross worked with me in x-rays here. He was a really bright man and he — well, we worked together a good deal and bull sessioned things over a good deal. Bill Hanson, too, George Harrison, they were students, but they had ideas and certainly influenced me.
What do you think is the best way of handling graduate students?
Well, if they're all good ones, I'm not too sure if the best answer isn't one that was given by I think it was Rowland, but I'm not sure, when somebody asked him how come he had such brilliant graduate students with him, "What do you do? How do you make them that way?" The answer was, by systematically neglecting them. That's just what Sabine did to us in that optics course — turn them loose. Here's what you want to do.
You toss them in the water and see if they swim.
And then of course you have small graduate classes, and if you plan your lectures pretty carefully, and again don't insist on any particular order of subject, but be willing to change your course in answer to questions. Then explain things as carefully as you can and encourage them to think about them. I'd say that was about it.
Would you want to say a few words about what kind of research you are doing now?
Yes. What I'm doing now is work on solar wind and plasma in the neighborhood of the earth, and how I got into it was rather curious. I well, sometime back, several years back, I got thinking over some of the things that had come up in electrical theory courses. I'd written papers over the course of the years on such matters in the American Journal of Physics, and there were some ideas that I thought really should be laid out there because they were — some of them were good ideas in connection directly with teaching. Others were the proper understanding of really what was going on in electrical principles. The idea that I wrote up first in this series, was one for answering the perennial question students ask when you show them the attraction of like currents in parallel wires, they've asked and I've had it asked hundreds of times, since like charges repel, why do like currents attract? Well the — of course why is a big word. You could say it's God's will or something, but that's not very satisfactory. Next down the scale you could appeal to Maxwell. But that doesn't go very well with freshmen. What you can say is that here you've got these electrons drifting along side by side, slowly to be sure, but if you say the wires have no not charge, just current, then the fellow going with the electrons will see a Lorentz contraction of the distance between protons and will see an expansion from what you've had as a Lorentz contraction as the distance between electrons, therefore he will see the wires as positively charged. You figure out the amount of that and the attraction that he gets on the electrons in one wire by the positive charge in the other wire is exactly the thing we call the magnetic attraction. The students, even freshmen when they got along to electricity have heard of the Lorentz contraction, the Michelson-Morley experiment, and sure enough there's the why of it, and that's why the velocity of light gets into the relation between the two forces, and sure enough that's a very useful trick with freshmen. So I wrote that up and promptly got it turned down by the American Journal of Physics on the ground that it wasn't so.
I wonder who refereed that?
The man who refereed that, I don't know, but the man who took the case up with me and tried to explain to me why it was wrong was editor Michels. Well. I tried to explain to him why it was right, and we argued that back and forth for a few years. Meanwhile, I figured that another thing that ought to be done would be to set teachers straight on the matter of magnetic fields of moving things. That is to say, long ago I read in Lorentz' theory of electrons that he had no use for moving lines of magnetic force. He had put up good convincing arguments, and they convinced me anyway, and I know that about the time that I read those things, E.W. Cannard had done an experiment with a rotating magnet in which he proved mighty well that the idea of moving lines of force rotating with that magnet was just absolutely wrong, experimentally. He did it, he said, to test Lorentz' theory — and he came out with the result that Lorentz was right, and he made a very optimistic statement that from now on when affects of moving magnets are discussed, lines of force will have to be considered as not moving. Fifty years later the textbooks had them all moving. I figured that that was something that teachers really ought to be set straight on. I wrote it up in the Britannica, I've written a general article on electricity in that in which I had this business about parallel wires there and reasons why the moving lines idea didn’t do well, because you had to make one rule for one kind of a machine, and another rule for another kind of a machine, and very often before you had to say that you had a so-called rotating field generator the lines of force of course had to stay with the coils to maintain them. If you have a three phase 60 cycle motor, the lines of force have to go around and shift from one coil to another all the way — conflicting rules.
The only thing the rules had in common is that the speed that they have to make is easy to remember, and somehow looks obvious if you don't think much about it. Well, I figured I had to set that straight, so I wrote a paper on that and explained just why in the first place I thought the elementary textbooks had a fair excuse for retaining the idea of moving lines of force because the advanced books — well most of them oversimplified the Lorentz transformation for bodies at laboratory speed, and as a result of the oversimplification, if you tried to follow the ideas that were in the advanced text books in talking about elementary things, you got bogged down, and therefore, people had a fair amount of excuse for failing back on moving lines. I wrote that up and explained it in detail, and I threw in the business of the parallel wires, and Michels said, well, it was all right about all this other stuff, but the parallel wires was still wrong. Would I let him publish without the parallel wires. So I said, all right, go ahead and publish without the parallel wires. Then I wrote up a treatment of parallel wires basing the production of the charges directly on the Lorentz transformation which he had published in this other paper. Then he couldn't squeeze out of it. Then he had to publish that. About that time, I'd known Alberta here for many years slightly. Actually, she had been a student in one of my first classes but then she had gone away and got married, lived elsewhere and when she came back to this neighborhood, I didn't know her at all. I didn't recognize her. She was Secretary of the Local Amateur Astronomical Society and she was working there at Ames.
She was a very highly skilled aerodynamic theorist working on transonic aerodynamics which is the hardest branch there is, but the aerodynamists had to go on upstairs with the test pilots into outer space where there wasn't any air worth working with and there were a lot of electromagnetic fields. Alberta started asking me questions about, well, as we happened to meet out in Hawaii at a Pacific Science Congress out there, she started asking me questions about these things, and I explained some of the things to her. Then, of course, pretty soon after that the question came up how about all those moving lines of forces that people are talking about in theory of solar wind and magneto-sphere, and the rest of that. I said, well, they're all wrong, that's all there is to it, and she showed me a lot of these things. I thought, well, holy smoke, this has got to be set straight, mostly on rotating things, and Leonard Schiff, the head of the department here had written a paper back in '39 on his scheme for applying the field equations in rotating coordinates by the use of fictitious charges and currents. Well, this was for fictitious charges and currents either within the atoms or in high vacuum where you didn't have to worry about permeability and dielectric constant, and I figured that I'd simply have to adapt — well, I had adapted Schiff's theory for my own purposes to make a qualitative statement about such things in the Brittanica, so I figured I better write that thing up right, and Alberta was interested in it and she took it around to John S, who was chief of the theoretical branch there and asked him what he thought of it. He said, "Well, we’d better get that man on as a consultant." So, here I am.
How long have you been working at Ames now?
About a year and a half.
Do you enjoy the work?
Oh, yes. It's very interesting.
What about your avocations? We've been talking the entire day about your vocations. What do you do for fun?
What I used to do when I was young, was sailing a boat every time I got a chance and later when I came out here I found that this was a rather disappointing state for sailing, but I found that it was possible to go up for vacations to British Columbia, and there's wonderful water up there. That was kind of a good idea for a while. When light airplanes began to get cheap, I thought, here why not get back into the game, and so I got back into flying, and I've done a lot of flying since. I've sold that since I've retired. It's rather an expensive hobby, and my doctor says he wouldn't think of signing a medical certificate for flying for anybody over 70 no matter how healthy he looked, because he's too liable to have a heart attack. Then my wife, Olive, and I went to the Islands quite a number of times. We were out there about five times all together. She used to fly around with me a good deal, but about the time I retired she began to need more rest, under doctor's orders, and not take long trips such as we had made, and that took half the fun out of it, because I had flown so much with her. Then we took automobile trips, and one thing or another, and went out to the Islands and soon — then she died rather suddenly back in ‘61, and I sort of felt like a fish out of water for a while — for quite a while. I tried to keep the garden going, not a very exciting avocation, and then it wasn't too long after that I got acquainted with Alberta and got interested in the Sierra Club hiking and so on, and she liked to drive out to the mountains and so on. I'm sort of back outdoors again pretty often that way.
We’ve covered many things today. Is there anything that we haven't covered that you want to mention?
I don't think so. I think we've pretty well covered the ground. In fact, the only thing is I might say I don't quite see why my special contribution to science is interesting enough to put down anyway.
They spelled their names differently by the way, Pierce, P-ie and Perce, P-ei; they pronounced them differently also.