Notice: We are in the process of migrating Oral History Interview metadata to this new version of our website.
During this migration, the following fields associated with interviews may be incomplete: Institutions, Additional Persons, and Subjects. Our Browse Subjects feature is also affected by this migration.
Please contact [email protected] with any feedback.
This transcript may not be quoted, reproduced or redistributed in whole or in part by any means except with the written permission of the American Institute of Physics.
This transcript is based on a tape-recorded interview deposited at the Center for History of Physics of the American Institute of Physics. The AIP's interviews have generally been transcribed from tape, edited by the interviewer for clarity, and then further edited by the interviewee. If this interview is important to you, you should consult earlier versions of the transcript or listen to the original tape. For many interviews, the AIP retains substantial files with further information about the interviewee and the interview itself. Please contact us for information about accessing these materials.
Please bear in mind that: 1) This material is a transcript of the spoken word rather than a literary product; 2) An interview must be read with the awareness that different people's memories about an event will often differ, and that memories can change with time for many reasons including subsequent experiences, interactions with others, and one's feelings about an event. Disclaimer: This transcript was scanned from a typescript, introducing occasional spelling errors. The original typescript is available.
In footnotes or endnotes please cite AIP interviews like this:
Interview of Harry Mimno by Katherine Sopka on 1977 February 10, Niels Bohr Library & Archives, American Institute of Physics, College Park, MD USA, www.aip.org/history-programs/niels-bohr-library/oral-histories/32160
For multiple citations, "AIP" is the preferred abbreviation for the location.
Interview concentrates on the history of the physics department at Harvard University. Topics discussed include: Rensselaer Polytechnic Institute; Radcliffe College; Massachusetts Institute of Technology; early radio broadcasting; National Electrical Code.
What we'll do is to let it run. Harry —
This gives some of an idea as to, as I said, why I had contact with as many different things around here as eventually did have. It's a little bit surprising. But this is the reason.
I see. Alright, why don't you start, Professor Mimno?
Yes. A little sketch of my own education explains [???] why I am perhaps an authority on as many different aspects of the physics department and engineering.
Well, very good.
I was, to start with, I was born May 8th, 1900 in Chicago. When I was about seven my family moved to Pleasantville, New York, and my school days up to college were spent [???] is now Reader's Digest [???].
And that means that while I was in my senior year in high school, World War I was well underway. We were not involved in it yet, but the high school started a Volunteer Drill Corps of junior and senior high school students to get them a little bit prepared for what they might be involved in as it looked then. So I graduated from high school in 1917, and had a small scholarship at the Runsler Polytechnic Institute in Troy. So I duly reported there in 1917 in the fall and was a student at RPI Runsler Polytechnic. And then I graduated in 1921 with a degree of Electrical Engineer. Having graduated, no, check back just a bit. Having graduated from high school and enrolled in my freshman year Runsler, I was attracted to a rather unusual camp at Plattsburg [?], New York for the summer of 1918. [???] of course at that time had been a training going on for a number of business people and such that might be thrown into the war. And this was the first time that students as young as 18 years old had been invited at all to Plattsburg. The reason was that the, well, the Congress has evaded somewhat as to whether the draft age should be lowered from 19-21 to age of 19. Were students in their teens, late teens, capable at all of taking a tough Army education or would it be unwise and meaningless to induct them into the Army until as late as 21. So we had a large group of 18-year-olds divided into companies and divisions, and we received a very strenuous training on what now we call commando techniques.
So we were trained by experienced Europeans, French and English officers who had been hugely successful with the use of a bayonet. So we were perhaps almost the last group that received the full bayonet training from experts who would qualify by [???] of at least [???] [???], and therefore were sent back to train people to go out and do likewise.
I see. You were just about 18 at this time.
Yes, I was 18 at the time. So this, again I would in retrospect call commando training. But a great deal of that was [???] hand-to-hand combat, seriously intended, very seriously intended, and not just for exercise.
So this took all of the summer, and I came back to Runsler Polytechnic in the fall and at that time the likelihood of [???] involving the United States was more serious and —
This was the fall of 19—?
1918. In the fall of 1918. In the summer of 1918 was my intensive training at Plattsburg. Then at college the student body, including the freshman — I finished one year at Runsler, and this was my sophomore year — were organized into a student training corps. Not part of the regular Army, but again as pre-training assuming that most of us would be officer candidates later. So I was one of the few that had had this Plattsburg intensive training in the summer. So that brought me into the countermeasures against the flu epidemic which in 1918 was very serious. I didn't catch it, but took part in taking care of a very large number who did.
Where these fellow students you mean, or people —?
Yeah, students [???] I guess. So that took care of — yeah. November 11th, 1918 is towards the end of my semi-enlisted part of my training. I was detailed of Officers Training Camp to be held at Fortress Monroe, which was the great artillery training center, so prospectively was to become an artillery officer. My papers were transferred from my school, RPI, to formal induction into the Army as an officer candidate, was dated November 11th, 1918.
That's interesting. Where was Fortress Monroe located?
In the middle South, Carolina I guess it was, but — And it was some instruction also in officers' training in New Jersey. But for obvious reasons something else had occurred on November 11th, 1918. My orders canceled my telephone [?].
So I finished my 4-year career as an Electrical Engineering candidate, graduated in 1921. And by that time the interesting was beginning in radio broadcast [???]. Only a few stations in the whole country at that time, but they were beginning to be interested in it. So the authorities at Runsler talked with the Western Electric people who were themselves adventuring in the construction of a standardized broadcasting station, and they were building units of 500 watts, which today we'd regard of course as a flea powder [?] station. But at that time it was interesting, because it was a transmitter actively using vacuum tubes of appreciable power output. So RPI agreed to buy one, and it turned out that in my high school days I had been copying down code and [???] oh cereal boxes and so forth, [???] well known cereal boxes and galena [?] crystals — before the days of vacuum tubes at that time. But I'd had a little experience in the reception of dot and dash signals. Then in my freshman year at, well, during my undergraduate work at Runsler I joined a radio club, which was a new thing in those days. And they had no facilities up at the hill where the college was located, but we borrowed some space from the YMCA downtown, and transmitting apparatus was not vacuum tube. We hadn't reached that stage yet. It was what was known as rockfresher, and the spark coil and considerable power, and it sort of drew sparks from the [???] all over the YMCA it turned out. So we established a creditable record for distance covered by spark [???] in the radio club. Hence when the authorities at Runsler decided that they'd like to have a broadcasting station they also knew that I had had some experience in radio operating [???], brought me into the details of how to do it on putting this newly built small radio transmitter into an operating room [???] we [???] the room. And above all, [???] studio. These were almost nonexistent up to this time. But I designed a place to put the microphone where people could talk into it in an office next to it on the fourth floor of the laboratory, which I had decided was a good place to put the transmitter. So this was radio broadcasting in its infancy. Now there were some interesting — you don't do this without having a few interesting experiences. Well, Governor Smith was a candidate for the Presidency. He of course was invited to this brand new device of radio broadcasting stations. So I had to explain to Al Smith the things behind the panel, which nobody had seen before, when there was a severe thunderstorm outside, and a crash of lightning on our antenna, practically a direct hit. So I had to push the Governor candidate out of my way to get at the controls real quick or the whole transmitter might have blown up in his face. That was my introduction to the art of broadcasting as distinguished from the technique of it. Well, I continued and took my degree in Electrical Engineering in 1921 and was appointed an instructor at Runsler Polytechnic Institute, in charge of the broadcasting station but also general instruction in electrical engineering as a whole. And we had as the department head a very [???] electrical engineer who was chief engineer at the Harvard [?] Electric Light Company as well as having a professorship at RPI.
So this was good experience for me in electrical engineering from a real authority. And I [???] electrical engineering and communications engineering. So [???] that time more electronics was beginning to come into the radio part, both in broadcasting and also in telephony. And I felt that I lacked experience in pure physics. I handled electrical engineering applications, so it still worked out, but the new science of vacuum tubes from construction and novelty [?] was something I ought to get from a higher authority than this. So I took a leave of absence from RPI as an instructor and came over to Johnson Laboratory, talked to Professor Limon [?], and arranged to register as a graduate student in physics here.
What year was that that you first came to Harvard?
That was in 1925. So I was a graduate in physics at Harvard. I graduated with an AM [?] degree in 1926 and then spent quite a series of experiments on a thesis in physics and also some teaching here in physics and in engineering. For the most part, appointments were, appointments in physics under the engineering, because by that time this was my main interest in [???]. So I taught some courses at Radcliffe and some at Harvard, intermediate physics courses, and in 1928 I returned to RPI as I had been on leave of absence with a promise of assistant professorship while I was away for that period. So I talked it over with Harvard and with Runsler, and it was decided that it would be very satisfactory on both sides if I would go back to Runsler and teach at Runsler some of the novelties which I had learned in the four years at Harvard. So I returned as a graduate student in physics. Well, I came back to Harvard as an assistant professor, and meanwhile in my lectures at Runsler I had called attention to the new facts of atomic physics involving transportation of other atoms than radioactive atoms; in particular [???] had been here during my period and I've heard a number of lectures from him.
So I brought the first news of other impending events in physics. So you get induced transmissions might be possible and that the curve of atomic weight was of importance; that the lighter weights, the atoms at the two ends of the atomic series, helium and hydrogen at one end and the radioactive elements and some others including plutonium at the far end. Both had the potential for yielding some energy by changing their atomic state.
So this was RPI's warning [???] things moving in fission [?] even more than I had realized when I was thinking of vacuum tubes.
Which years now was it that you were back at Runsler? Was that around '29?
No, I actually took my — while I was teaching full time I was finishing a thesis on vacuum tubes with Professor Jaffe. So my actual doctorate was in '33 I guess, it's about that period. So I then continued teaching at Harvard and moving through the academic ranks [???] in 1965, on my 65th birthday. And during that period I had had various chores other than teaching. For one period [???] and I was acting chairman of the department of physics at that time. Then another time the chairman of the department of applied physics was similarly away, and so I was [???] acting chairman of the department of physics and later the department for applied physics. About this time the dean of the engineering applied physics retired and [???] English professor had been invited to [???] the deanship, probably because of having events in physics in England. This was not [???] couldn't come, so that for the period of the early 1930s I was an acting dean in the division of engineering and applied physics as well as acting chairman of the department of physics at the same time.
You had a lot of responsibility.
This meant that I kept my own office. By this time there [???] 326 on the next floor below, and I had dictated letters to [???] you see from engineering headquarters at the dean's office of engineering where I theoretically was [???]. So at this time I invented something which is the only thing that the newspapers ever understood. I was dictating on wax cylinders at that time. The transport then of the wax cylinders containing my outgoing letters had to be taken over to Pierce Holmes [???] going down two stories and up two stories [???] away. So I arranged a little thing like a clothesline with a pulley at each end, but instead of pulling them by hand of course I had a little aluminum cylinder which contained two of the wax cylinders, and instead of having a secretary working all the time pulling this back and forth I rigged up of course an electric motor which would do it automatically. So this hit most of the newspapers, [???] the third floor physics laboratory, third floor laboratory. And this gave me notoriety for all of 24 hours I think [???] picture of this was on the front page of the papers. Now, more seriously, by this time the physics department and the engineering grew. We were both feeling a pinch of space, so it was desired to build what is now the building you are in, the Research Laboratory of Physics. In part for the use of overflow from the engineering school and mostly for the use of physics. And my appointment was still primarily as a professor of physics [???]. So with the new laboratory under design, both Professor Pierce [?] and Professor Limon asked me to help them respectively represent the physics school and engineering school in supervising the architects in construction of the building. So that is how I happened to learn more than the usual instructor would learn about building construction and this one in particular.
And so I was also doing research in [???] application [?], which is why the third radio towers on the far end of the research laboratories. This was so I could get big antennas from that point. They were too high, antennas [???]. Now other little chores, I having finished supervising the construction of the Research Laboratory of Physics, there were memories of the [???] and the construction of an explosion in Jefferson, which was a serious accident that had taken place before my time, but it was desired to do at little or no cost a re-vamping job on Jefferson, in particular to put in a completely new electrical system. And we put together oh a dozen or more electricians from the University of [???] office, and I acted as designer and boss on the construction of [???] in Jefferson.
When was the fire that you mentioned? When did that take place? Did that take place before this rewiring that you're —?
No, that took place directly after rewiring.
I see. Okay. I'm sorry for interrupting you.
Fortunately it took place in the daytime [???]. But the opposed question, this wiring, being a big, open laboratory, was done by skilled electricians from the [???], the code book and everything, and so did I. The day after the fire we got the janitor to put the ladder up to the high rafters so he could see [???] what had happened. And it was obvious that the standard wiring used at that time, which was a steel-covered so-called BX [?], which is a steel metal tape galvanized bound around the live wires and therefore protect them against anything. It was impossible to damage it, it says here. But everywhere that this wire had been against the wooden beams in the attic visible from the floor there were little charred marked marks corresponding to each turn [?]. So it was obvious that in the case of a short circuit in a fixture, which is BX and so forth had designed to protect against, this can't do any damage because immediately it blows a fuse at the fuse box which is at the other end of the [???]. But it hadn't. And the fuses were of the right size, they were [???], a conservative [???] they should have blown, but this was I guess almost a year after the installation of that wire, and therefore it was no longer bright and shiny but it was a little bit oxidized. Hence the resistance between turns, adjacent turns, was not [???]. It was — [phone rings]
So it became obvious what had occurred. So I immediately of course rushed to the library and carefully re-read all the instructions of national electric code, which the electricians had followed and which should certainly have prevented anything like that. It was unknown to the National Electric Code. There were many, many precautions on how you prevent dangerous voltage affecting [???] throwing a switch, [???] against [???] as to how one should wire it so this can't happen. But nobody had thought of this possibility of a piece of BX cable failing to blow a fuse, failing because the current, once the metal is slightly corroded, the current has to go all this long route this way rather than just shooting down to blow the fuse out.
So later on I was chairman of the Standards Committee of the Electrical [???] in charge of okaying National Electric Codes. This little impression [?] oratory on the subject of how the designers of the code had missed this one. So a year or so later I had the occasion to put some BX in my own house, and remembering what had happened in the laboratory I bypassed it with heavy copper wire end-to-end so that it could corrode itself to pieces and nothing could prevent blowing that fuse. Now following what was obviously the repetition of the accident that had taken place, the manufacturers of BX began to put a bright and shiny plate of copper wire inside the shell parallel with the wires that were supposed to [???] the current to [???]. And this was a step in the right direction. I didn't like the size of that wire very much. I was very much [???] myself in doing the same thing [???], but every time I went to the electrical shop for several years after that, the size of that wire had increased, big enough to satisfy [???]. [???] departure from our story [???] amusing.
You then were involved with both the rewiring of Jefferson and with the planning for the electrical facilities that were built into Limon.
And...yes. Now along the way, I handled the accidental responsibilities. Curtis [?] Street was interested very much in cosmic rays and deflecting [?]. He needed an enormous electromagnet to do this [???] to pay for it. So I said this is a [???]. I knew that, from electrical engineering experience, that there were old power stations not only continued in use because in case of a breakdown the modern station [???] and principal could take over. It was a very nice excuse. The more important reason was that as long as they were wired up and hitched onto a circuit the switch could be [???]. They could earn their 8 percent or whatever it was in the investment. So with that knowledge, I got in touch with some of the senior electrical engineers in [???] Anderson. And they explained how important this was to Harvard, and so they said, "Sure, take them all [?]." So this developed into a very interesting cosmic ray [???] housed and [???] so that the [???] used by Harvard for years. And then that brought me into a sphere of influence in cosmic rays, and [???] Curtis Street had a graduate student and they were both building apparatus to take to the Andes above Lima. Unfortunately the very capable graduate student who was almost ready to take off with [???] suddenly caught something serious and died. So in that emergency —
— [???] asked me if I would be interested in going along as his assistant to the Andes and chasing cosmic rays around at great heights. So I spent one summer with Curry [?] on that [???]. And —
That must have been interesting. Did you have a chance to be a tourist at all, or was it all work?
Yes. We spent ten days on top of the biggest hotel in Peru, and then that was for measurements on cosmic rays and essentially at sea level. Then we went up the highest railroad [?] in the world, which is not the one that crosses the Andes from Argentina, but one that goes up to a copper mine. That's 16,000 feet in the Andes above Lima. So on the way we stopped off at a famous old Indian city on [???], which is about — it's in the valley between two ranges of the Andes. And it's high enough so that [???] troubles due to the shortness of oxygen in the air. [???] already something that troubles you, you don't run around very much at 12,000 feet. But then we continued. This took us out to the [???] [???] Observatory, which we were guests of [???] Observatory, and took over in their horse stables [???]. Then the [???] stayed on the railroad, stops at [???], [???] and the copper mine [???] which shows from 12,000 up the valley of the Andes to 16,000, [???]. And this is really high up.
Yes. Sixteen thousand feet up is.
We set up our apparatus there at the third location and spend a couple weeks at that altitude.
Was the weather severe? It was summer in the Northern Hemisphere, but it would not have been—
This was far below the Equator, and it was fairly warm at even Lima, although there is a Pacific current which cooled that particular spot at 12,000 [???] region. And at 16,000 of course it was deep winter. It's [???].
Well, so much for that. Pearl Harbor took place. Well, we had half a dozen naval officers and their families, large [???] families, taking electronics courses of course before the war, [???] the war as far as we were concerned. So when they arrived it was our custom to invite them to our home in Lexington as an introduction to the things that they would be doing during their year of residence at Harvard. So on — well, it was November 11th, 19 —
Pearl Harbor was December 7th, 1941. It's engraved in all our memories.
That's right. December 7, 1941. They had arrived and we were having a tea party in our living room, and I never saw any tea party end so suddenly. The news of Pearl Harbor came over our radio in our living room, and of course the officers had to go immediately, jump up and report for duty at various assignments around the world.
[???] to Pearl Harbor. Then shortly after that, the [???] of radar installations had begun at the instrumentation laboratory especially at MIT. So this brought very much to the local attention at Cambridge, and it was apparent that our training of some six electronic officers per year [???] useful wasn't likely to amount to much, considering the obvious basis for what was going to happen in radar. So because of my appointment as acting dean for a while at the Engineering School, I was by this time well acquainted with Professor Compton at MIT, and course [???] at Harvard about this time in office at Harvard. So I wrote a short note to Jim Conner [?] in Washington saying, "We've been doing this teaching of radar of electronics officers [???]. It's obvious that radar is going to require much more effort of this sort, may I point out that Harvard has facilities in which it could do some useful employ [?]." The telephone reply from [???] was in effect, "Get on the next train and come down here at once." Because he and Compton had been worrying about just how to handle this problem of this obvious radar [???].
The need was probably obvious, but as to how to go about satisfying it without starting from scratch would have been more difficult than —
That's right. So he explained that the radar programmers [?] were [???].
Excuse me. [tape off, then back on...]
...decided that the job to be done was really a much more measuring [?] than I really realized and that the suggestion I made was very much in line. So I arranged the next train back to Boston and started talking to Professor Jaffe, who was the director at Crowe [?] Laboratory at that time, and we arranged that he would start moving on the attraction back to Croft [?] of many instructors that had graduated from Croft, if his whereabouts were known and could be made available for anything as urgent and important as this. So we began by arranging for 200 people that were presumably graduates in electrical engineering but did not know electronics yet, and we would take them in units of 200 for three months intensive course with the instructing staff that Jaffe would assemble, and the laboratory facilities and space facilities which were partly my job to assemble that. So this meant that by Pearl Harbor day we had had two experimental classes of that size, successively, and then after graduating from our introductory electronics course they went to MIT for the radiation laboratory people to set up a course for them in practicing on the particular SER-584 [?] radar [???] that was an outgrowth of MIT's major effort. So that took us to Pearl Harbor day, and we had graduated our second course just about that time. And then with America obviously now in the war with both feet, it was no longer possible to do it in that leisurely a fashion. We still needed the three months. So he arranged to bring in 200 people per month, most of them by this time already in the Army, I guess all of them by this time in the Army, for Croft instruction and then for practice on the apparatus at MIT.
So, instead of having 150 and [???] three months another 150, or 200, we had 200 coming in the first of every month.
Oh. Giving you 600.
My job was to commandeer from the Law School especially and also the other buildings around here. Practically all the laboratories that I can see from Croft roof. So the Law School was down to only a few students in the corner.
And many of the other buildings that you see around here were all classrooms for this major effort. It was highly informal the first day. They had no, all the officers they had were oh, captains and second lieutenants and so forth to be trained they needed something for the incoming officers to report to. So we arranged this completely unpermissible manner as far as Army discipline is concerned. They reported to me, a civilian. And then when they were to go to MIT, the normal Army procedure is you return to your home base and then you are told where you are to go, so that if an officer from New Mexico had come to Cambridge for his elementary course of three months, in principal he had to report back to New Mexico and get told to come back to MIT.
Oh, I see.
So we short-circuited that by issuing the officers orders in short [?] upon the Jefferson blackboard.
Oh, how efficient. Excuse me.
Telephonic authorization from Washington. But after enough turnover in this the higher ranking officers appeared. We had three colonels. And so each of those I guess in succession made the officer to whom they would report that at least there was an officer.
I see. I want to turn this over. I can tell from the — [tape resumes...]
Yeah. We were training just about 6,000 officers, and was responsible for the successive major part of the radar effort.
That was 6,000 officers over four years or so, and each one of them stayed three months or —?
Three months here and three months at MIT.
I see. Well that was certainly a major —
The [???] itself was really done in a marvelous manner by MIT group. This was not an MIT project, but a project of perhaps 50 universities collected at MIT to work on things like this, and this was their first major accomplishment.
Was this activity that you are speaking about now an adjunct of the radiation lab at MIT?
It was the first major success for the radiation laboratory at MIT, getting these into the — I guess Westinghouse and GE, various major companies, again to make the component parts which would fit together into an SER-584 radars.
So, this — a few, when they first appeared before they were officially in use, the first three I think were sent to Tripoli for [???] to try it in practice. They had seen the makings of this at MIT. Now they saw it in the flesh and could begin to make use of it. They made use of it at Angio Beachhead [?]. These three radars that were pushed ashore from a barge just when the German counterattack was devastating and would have quickly wiped out the American forces that had landed at Angio. The alternative was that when these were set up the first night they were in use controlling the guns, the loss of the German planes coming under formation was [???]. They weren't being able to pull [?] much of it in.
I'm told this by some of the officers that we had trained, and coming back they said, "It helped us to accomplish something."
It made them appreciate their training. Can I ask you a final question before you leave?
All of this time Croft activity was part of the physics departments, wasn't it? I mean it wasn't until after World War II that the, first the department of engineering and applied physics —?
No. [???] of applied physics. Having [???] for years.
Oh, I see.
I held a professorship in physics and in engineering.
And the courses I taught were attended about equally by the students in engineering courses [?].
I see. But then at the time — well, up until your retirement, you were then in the division or were you still within the physics department?
Still in the physics department.
I see. It's interesting for me to try and sort out the various developments in [???] —
Yeah. In electronics. There could be no sharp margin between what student would be in physics and [???].
Well, I remember when I was an undergraduate here there were [???] halfway down the line and as you went in that direction [???] you were going across now.
We had a more [???] division when I had a little cauliflowering back and forth for the [???].
Yes. Well, thank you very much. It's been a pleasure to —
If you need any more specific information, that's the kind of thing that I had to do with, the letters and such are all in the files of course at [???] in [???], anything that I wrote the [???].
Yes. Well, thank you very much.