K. Uno Ingard

Maling:

Uno Ingard, and this is George Maling asking the questions. I know you were born in 1921, but in what city of town?

Ingard:

It was on the west coast of Sweden in the down of Gothenburg.

Maling:

And what kind of education did your parents have?

Ingard:

My parents had the compulsory education required in Sweden at that time. But they did not attend college.

Maling:

They did not?

Ingard:

No.

Maling:

But when you were in your formative years, 12 to 16, what did they do then?

Ingard:

My mother was a full-time homemaker. My father was a mechanic, and he had a number of hobbies. One of his hobbies was to design and construct mechanical puzzles of various kinds, and he challenged me to solve those puzzles. Another hobby that he had was to explore on bicycle the interesting areas on the west coast of Sweden, visiting lakes and less-traveled roads. And ever since I was 12 years old, I went with him on those trips, and he actually wrote articles in the local newspapers on bicycle trips — one-day trips and two-day trips, an outline exactly how to do it.

Maling:

Very interesting. And you were bicycling; you were quite an athlete when you were young. How did you get interested in that, and what was your specialty?

Ingard:

Athletics came very easily to me, because I was fast and I suppose well-coordinated, and my first experience with competitive athletics was the championship for schoolboys in Gothenburg, and I remember when I was 12 years old, I won first prize in high -jumping, and that was my first competitive experience in athletics.

Maling:

So you were in track and field?

Ingard:

Track and field was my main, but I did play all kinds of team sports-soccer, ice hockey, and something called handball, European handball. I played everything in sight. I loved athletics.

Maling:

And you must have been very interested in science when you were in your secondary school. Were there any special teachers there or people that you recall?

Ingard:

In secondary school, I guess secondary school corresponds to high school?

Maling:

Yeah.

Ingard:

Not really. There were some teachers that-I mean, the names don’t mean anything to you, but there was one teacher in mathematics that I liked very much. Apart from that, I have no recollection of any special teachers that impressed me.

Maling:

But at some point, you must have known that you were going to go to college. How did that — did you get interested in acoustics at that time?

Ingard:

No, I had no interest in any specialty like acoustics or anything like that. But my favorite subjects in school, at that time was math and physics. And I enjoyed problem solving. So whenever I got a book in physics and mathematics, I usually on my own solved all the problems in the book that was written up. So that was sort of my hobby.

Maling:

And where did you get your undergraduate training?

Ingard:

The undergraduate training was, let me see now. I have to fit it into the Swedish system. Undergraduate is college?

Maling:

Yes.

Ingard:

The first undergraduate experience was at something called the Chalmers Institute of Technology in Gothenburg, Sweden, and that was a four-year college. It was a three - or four year college; I don't remember which. My field was electronics. The teachers there, on the other hand, I do remember-teachers who made quite an impact on my future interests. One of them was in electrical engineering, electricity, and electromagnetism. His name was Dahr. And another one was Hogner, another very good teacher in mechanics. And the third was Rydbeck, whom I later worked with. He was my supervisor for my undergraduate thesis. He was not particularly a good teacher, but he was a very inspiring man to have as the supervisor. He also had experience from this country, because he got his doctor’s degree at Harvard in applied physics.

Maling:

I see. And when you started Chalmers, you must have been convinced that you were going to study science and engineering.

Ingard:

There was no doubt about that, yes.

Maling:

Did you ever think about the difference between an experimentalist and a theorist?

Ingard:

Oh, yeah. I did, and I was inclined toward theory, but then through Rydbeck, he put me on experimental projects as well, and through my father I had mechanical skills, and I could operate lathes and machines. So eventually, it became a combination of both experiments and theory.

Maling:

Did you have any feeling for what kind of life you were going to have as an engineer or physicist when you were in your undergraduate years?

Ingard:

Well, not really, except…

Maling:

Enjoy doing it, probably.

Ingard:

Enjoy doing it, solving problems, and hopefully publishing some papers. That was on my mind already at that time.

Maling:

Interesting. Then after that, you went to graduate school. That was also in Sweden.

Ingard:

Yes, it was at Chalmers, too. When I got my degree at Chalmers, for the first time, they instituted a new field, which they called licentiate degree. It was a two-year graduate course on top of the undergraduate course, and I decided to take that. And at the same time, I got the job at Chalmers to take over the responsibility of the acoustics laboratory, because the man who ran that laboratory was going to leave after a year, so my supervisor Rydbeck talked me into, in combination with my licentiate studies, take over the responsibility for that lab. So I had to quickly learn the fundamentals of acoustics, and it was with mixed feelings that I accepted this job. And the reason probably was, you know, as an electrical engineer, I was used to making measurements with some precision, and here, I came down to a reverberation room to measure the absorption coefficient of some materials, and I found very soon that I could get any answer I wanted to-not any answer, but the variability of the results I got, depending on where I put the absorbers on the walls… So in frustration, I quit, and said, “This is not for me. This is not at all for me.” So I told Rydbeck that I don’t really want to do this. But after 14 days or so, several people talked me into continuing. So I finally gave up and said, “Okay, I'll try it for a year and see what happens.” So I did, and eventually I began to realize that different experimental areas, the accuracy that you can get depends so much on the field. Some of them are very approximate, and the other learn to take averages and make good, sound engineering judgments on the result. So once I got that into my blood, that when you are out in practice, you have to get used to not exact results all the time, but you have to make judgments. After having realized that, I sort of accepted it.

Maling:

After the licentiate degree, you went to MIT. How did that come about?

Ingard:

Well, first of all, I had to go to military service. I went for two years, believe it or not. It was after the war, and military service in Sweden was considered important, so that I couldn’t get out of it. So I went in for two years. But in the meantime, I had time to study on my own. So I did, and on top of that, I met Doris during that time. It was all right, but when I came back after military service to the laboratory, I had always thought very highly of MIT, and wanted very badly to get there, if possible. But after the war, there was very little chance of getting dollars in the currency-in dollars, in Sweden. So even if I had money, which I didn’t, but even if I had been able to borrow, it would have really been very difficult to get dollars. But fortunately, I discovered the Sweden-American Foundation issued a scholarship every year for studies in the United States. I hurried up and applied for that scholarship. I was kind of late in doing it, but I managed to get my application in in time. And lo and behold, I was awarded and got the funding with the help of my professors at Chalmers. They gave me nice recommendations. So I ended up getting the fellowship. Before that, I had applied to MIT physics department graduate school just to be on the safe side in case I would get… So I had the application in, and I was accepted as a graduate student in MIT. Once I got the fellowship, I was on my way, so to speak, to the United States. I had to arrange for a substitute person to be in charge of the acoustics laboratory, and a friend of mine by the name of Steve Ingemansson, he was up working in Stockholm, but I went to Stockholm and talked him into taking the job at Chalmers. He accepted and came down. Also, in those days, there was a housing shortage in Sweden, so it was very, very difficult to get a place to live. But my friend Rydbeck, whose mother was a politician, she had all kinds of contacts everywhere. She managed to get an apartment for Steve Ingemansson. So I went up to Stockholm and said, “Steve, I have an apartment for you in Gothenburg, if you would like to come down and get that job, take over for me.” So he did. He came down and got the apartment and moved in, and I went to the United States. Of course, there were many things before that. Before I went to the United States, unfortunately, I had a bad accident. So I ended up in the hospital with a severe brain concussion. I was in the hospital for maybe 14 days, three weeks, before I was even able to stand up. The time for my departure came closer and closer, and I still was dizzy. And when I went-we were then married, Doris and I had gotten married in the meantime. Doris and I took the trip on the Queen Mary to America. I was still very dizzy, even on the boat. And when I came to New York, I really broke down with all this confusion and new experiences. So I had a rough time. And when we came to Cambridge, we got an apartment in Cambridge. I had to go to bed. So I was in bed probably for 14 days, just to be able to stand up. Not a very good start. And my scholarship funds went to doctors’ bills. I had to go to doctors to see if they could do something for me. I went to one after the other, and I quickly ran out of money. So once my head cleared up a little bit, I went to the physics department to announce that I had arrived and I was ready to start school, and Slater was the head of the department at that time — John Slater, one of my favorite professors. So I told him about my problem, about my financial difficulties and my doctor’s bills that were piling up, and so I asked him, “Is there any chance that I can get a job — anything — so at least I can get my tuition paid for at MIT?” And then he said, “Well, as a foreign student, I think the chances are very slight, because after the war, all the priorities went to the returning GIs.” But he said to come back in a few days, and I'll see what I can do for you. So next week, I came back to Slater and said, “Here I am. What is the verdict? Can I get a job?” And then he said, “No, I’m afraid you cannot earn money by working. But,” he said-and he had this microsecond smile typical of Slater —“There’s nothing that says that you couldn’t get paid without working.” So he had arranged for me to get a fellowship at MIT. After that, he was a big hero at MIT for me. On top of that, I took courses of his, and I loved his way of teaching and his skill. So that was my introduction to the physics department. But my trouble from my injury did not end. So in order for me to sit in a class and take notes, I had to patch up one of the eyes. So the first term, or maybe a year, I had a patch over one of my eyes. As you pointed out, it was not a very good introduction to this country.

Maling:

But you managed to get your thesis done.

Ingard:

I managed to pass the oral exams, the doctors’ exams. It was a big hurdle, to start with. It went okay, so I managed. I remember, in order to avoid the pain, headaches, I had to eat a lot of sugar, a lot of candy. So I went to these written exams with a very big pile of chocolate bars, eating during the test. It was a two-day test, and I managed to get through.

Maling:

To get through both-two sets of exams. And then you did your doctor’s thesis.

Ingard:

With Phil Morse. Yeah, I think one of the reasons why I applied to MIT in the first place was that during my licentiate studies, my supervisor designed a bunch of books for me to read. One of the books was Condon and Morse’s Quantum Mechanics, and the other one was Morse’ Vibration in Sound. And I got fascinated in the similarity between these two books. So at one time, I almost thought that Morse had copied Condon and Morse and made it into an acoustics book. In any event, I enjoyed Morse’s book on Vibration in Sound very, very much. I remember I solved every single problem in the book.

Maling:

You said you were one that solved problems earlier.

Ingard:

Yeah. And in the process, I actually discovered some errors in the book, which must have impressed Phil Morse very much. Because he asked me to-he was then writing his book on theoretical physics with Feshbach, Methods of Theory, two volumes. So he asked me if I could possibly be willing to read some of the manuscripts, and I said, “Sure.” I was very proud that he asked me to do that. So I spent a lot of time reading these manuscripts, and, again, discovered some errors here and there. That was good for me.

Maling:

Yes, very interesting. After you finished, what was the title of your thesis?

Ingard:

I don't know what the title-it dealt with nonlinearities in sound fields-vorticity in sound fields. You know, the vortex rings and things like that. So that was my thesis.

Maling:

And you decided to stay on at MIT after that.

Ingard:

Yes, after that.

Maling:

Did you consider anything else besides MIT?

Ingard:

Well, first of all, I got a job offer from MIT as an assistant professor. Ned Frank was the head of the department, and I told him that I would like to think about it for a year, because I had my commitments to Chalmers to finish up-I had actually promised to come back after two years, or whenever I was through. He granted me a year’s leave of absence to think over this offer from MIT. So I went back and spent a year at the acoustics laboratory with my assistant Ingemansson, but at the end of that year, I was more and more convinced that I wanted to go back to MIT. So I resigned from Chalmers, and Ingemansson took over the leadership of the acoustics laboratory, and I went back to MIT and started as a young assistant professor at MIT. I was probably a little bit older than most, because of all this military service, and this double-I had the licentiate degree plus the PhD. So it was essentially four years of graduate studies instead of the customary three, perhaps. In any event, I went back to MIT and started work. And my first teaching assignment was teaching, as you could expect, freshman physics. It was for all the students — all the engineering students, all the students at MIT. They needed two teachers to teach the course, and I taught it with a friend of mine. His name was William Kraushaar. We were asked to develop a new type of course just to not get stuck in a rut. So we accepted the assignment to try to change the character of the course a little bit. So we based the course on conservation laws. So instead of starting with force, for example, we started with conservation of momentum, and we built tracks, called creation [?] experiments, and everything was built on experiments. So by condition [?] experiments, we discovered conservation of momentum. We had clocks that timed these cars running on these tracks coming and going, and we deduced conservation of momentum. Having done that, we introduced force in terms of conservation of momentum during a collision. So we introduced force that way-through conservation law. And then conservation of energy in the same way for elastic cohesions. So conservation laws got a very prominent position in our way of teaching. So we decided after a year to try to put this together in a book, and we wrote a book, Ingard and Kraushaar, The Introduction to Mechanics, Matter, and Waves. The title “matter” indicated that in the same introductory course, we taught thermodynamics and the elements of statistical mechanics, and elementary wave theory-both electromagnetic and acoustic. So that was written up in that book. I don't know if you’ve seen it…

Maling:

Yes, I have seen it.

Ingard:

Yeah, it’s around somewhere. And after that, we continued to teach that course for a while; I don't know how many years. I have to look back in my notes to find out. But that was my first teaching assignment at MIT. And then I taught a bunch of courses after that. And then the second teaching assignment was a senior course in what they called the Senior Project Lab. Senior physics students were given suggestions for projects. I was in charge of that course. And Sandy Brown had taught it earlier, so I got feedback from him how to run this thing, so I got a good deal of help from him. In any event, we gave the students assignments, and let them loose in the stockroom, and they had equipment of every conceivable kind. Once they had selected a project and picked out the appropriate equipment, they went ahead and did the project. So it was almost like a thesis.

Maling:

In all those years, you must have had a pretty good relationship with Philip Morse. Was he your closest colleague in the physics department?

Ingard:

Yes, he was definitely the closest colleague and friend, and I would even go as far as to say that he was like a second father to me during the first couple of years at MIT. We actually hiked in the New Hampshire mountains every chance we had. He was an avid hiker in the mountains. Ever 4,000-foot peak, he had to conquer. And he took me on these hikes. So I got to know him very well — very, very well. It was a good experience.

Maling:

And some of the other leaders in the physics department, the heads of the department, there must have been others that you were close to.

Ingard:

Yes, Tizca was another one that became a good friend of mine. Let me think a little bit about it to mention some other professors at MIT I had a close relationship. On that list are some of the heads of the departments that were the heads that were in the physics department when I was there. And I mentioned already John Slater. After him came Nathaniel Frank, and another one, William Buckner. Charles Taubs was head [???]. Hermann Feshbach, whom I knew very well through Morse and his writing on the methods of theoretical physics. Victor Weisskopf. And after that, I retired. I didn’t have much contact with the heads of the departments after they-and I think they all were very good leaders. Otherwise, they would have never been asked to be the heads. But my preference, overall, was John Slater. He was very good.

Maling:

And then you did a lot of research in the physics department. Was it all related to acoustic, or were there other topics?

Ingard:

No. You see, only during the first couple of years I was in the physics department was it possible to do acoustics in the physics department. I did teach a couple of courses in acoustics, I remember, but it was difficult to justify teaching acoustics in the physics department, so I had to turn to other areas. But the research I did in the physics department, in the very beginning, imagine that it was okay to do acoustics, and we had [???] established a field station outside Boston in Maynard — a field station for studies of atmospheric acoustics, refraction found in the atmosphere and all that. I think that was justified by — it was funded, as I said, by NASA, and also funded by other agencies, because during that era, the jet aircraft became very important, and everybody was concerned about jet noise over cities. So I think it was not difficult to get sponsorship to study systematically sound propagation in the atmosphere. So we did that. We decided to ask for such sponsorship, and we were generously sponsored to the point where you could get this field station with an equipped station wagon and all that out in Maynard, and we had that for a while-for several years. You probably may remember a little bit of it. We produced some interesting results, I thought. Another area, after having finished the acoustics work at the field station, I started getting interested in other areas in physics, and one in particular, which I still consider the best idea that I had in physics, and that was the scattering of light from the certain thermal calculations of a liquid surface. And the idea was simply that by doing light scattering from the random fluctuations in the surface of a liquid, by analyzing the spectrum in the scattered light, I could measure both the surface tension and the viscosity of the liquid through analysis. And that was written up in the-I got a good student to help doing these experiments. His name was Robert Catur [?]. The work was published in the Physical Review letters — two letters — and also I wrote an extensive article in Acustica. I don’t remember its title, exactly; “Acoustics and Physics in Engineering” or something like that.

Maling:

That would have been the Raleigh Medal.

Ingard:

Yes, exactly. And there, I described in detail. It was written up as an article in Acoustica. And on top of that, it was written up in the book that was edited by Feshbach and myself. It was in honor of Professor Morse. I think it was given to him at one of his birthdays or something. And there, I wrote a very detailed description of this experiment on the scattering of light from thermal fluctuations in liquids.

Maling:

Very interesting. Now, we did talk a little earlier about your teaching freshman physics and the senior projects, but there must have been other courses that you taught at MIT.

Ingard:

Yes, several courses. The major teaching assignment I had in physics was to teach what they called the theoretical sequence for undergraduate physics students, and that consisted of starting with mechanics, followed by electromagnetism, thermodynamics, and [???] physical mechanics. And I taught those courses in sequence probably for three or four years at MIT. That was one of my most enjoyable teaching assignments. After that, I taught courses in fluid physics at MIT, and a graduate course in thermodynamics. I don't know if it was combined with the physical mechanics or not-maybe one year it was. But I taught that for some time.

Maling:

Did you have any administrative responsibilities in the department?

Ingard:

I tried to avoid these things, but I was in charge of writing out a booklet on the activities in the physics department, in terms of projects and so on. So I had to interview a lot of people in the physics department to find out what they were doing-put on little pamphlet activities in the physics department. That was one, I guess you could call administrative job. Another work that you might consider administration was that I organized the physics contribution to the MIT open house. In my year, there was a fair amount of work involved.

Maling:

How about consulting work? Did you do any consulting work when you were in the physics department?

Ingard:

Yes, I did, and I did work for DuPont [???] with me and Stal Laval in Sweden. And during my work, I have some good memories from that consulting work during my time in the physics department, and I can just mention a couple of them.

Maling:

Yeah, that would be interesting.

Ingard:

One was a jet engine test show in Canada. Trans-Canadian Airlines had to shut down their testing facility, because when they tested their jet engines, they emitted a low frequency, very high-powered tone that spread out over the countryside. So there were so many complaints, they were shut down. I don't know how the work came to me, but anyway, I was called up and asked if I could come up and see if I could give any help. So I went up there to the testing facility and looked at the drawings and couldn’t find anything unusual about it. I had some experience from jet engines with consultation [???] with me and so on, and Stal Lavel for that matter, and that it probably how they got my name. So I looked at this test, and I couldn’t find anything wrong with it. But I told myself, before I go home, without having done anything, why don't I ask them to get me up on top of the stack so I could look down into in the stack? So they get some ladders, and I climb up on that stack and look down, and I saw a bunch of tubes there were not in the drawings, about three or four inches in diameter. And they had been installed as an afterthought to reduce vibrations in the walls. Since I had done work on aeolian tone, the only possibility is that you get aeolian tone from these pipes. But it wouldn’t matter; the aeolian tones are very weak; that shouldn’t cause any problem. I analyzed it a little bit more and discovered that the aeolian tone frequency was coincident with the first standing wave in the rectangle exhaust pack. So you get a feedback problem so that the aeolian tone excited the excited the standing wave. The standing wave, in turn, excited the [???]. So you get an explosion. You get a tremendous level. And I remember it was Sunday afternoon, and I was supposed to be back on Monday, so without knowing exactly what to do, before I left I asked them to get the welder up and cut down all these pipes. And then I went home; took an airplane home. And on Monday morning, I got a call from the facility saying that everything was fine. The tone was gone, and no complaints. That was very rewarding.

Maling:

Yeah, that’s quite an experience. They leave something off the drawing, and then you find it…

Ingard:

Exactly. The simple knowledge of standing waves and aeolian tone combine these things to solve the problem. Another had to do with the valve instability. That was at Stal Lavel in Sweden. They were just about to open a new testing facility at Stal Lavel, and had invited dignitaries to oversee and be present in the opening, and they turned on this facility, and the valve that was used in adjusting the flow after just a few minutes of operation failed-broke down. The amplitude was so enormous that the whole thing failed. So I got a phone call from that place and traveled out to [???] in Sweden-that’s where Stal Lavel was located. I looked over the situation and got some data, and that was a similar problem. It turned out that the valve frequency was the same as the first axial mode of the stack. But at this time, it was the transverse mode; it was the axial mode, so that the axial mode, being reflected from the top of the stack, came back and moved the valve at the same frequency. So you get a feedback from the axial mode to the valve, and the valve amplitude started to increase, and it failed so that the simple solution was merely to change the height of the stack to adjust the frequency of the axial mode. And that solved the problem, and as a result, I became a consultant to Stal Lavel. So they took me up there twice a year. Twice a year, I went up and talked to them about problems of this sort. And they had some of their valves made in Brombeldery [?] in Switzerland. So they sent me down to Brombeldery every time I went up to Stal Lavel. I automatically went down to Brombeldery to talk about their vibration problems, and it was a very nice experience.

Maling:

You were in the Aero Department at MIT as well as the physics department for a while. How did that happen?

Ingard:

In addition to being a consultant for Stal Lavel, I also did some work for Pratt and Whitney. One of the problems they had at Pratt and Whitney was the noise from jet engine fans — it becomes a little technical here — and the role of guide vanes. It was fairly well established at that time that in order for a spinning mode, as they call it, acoustic mode in a duct to produce sound, it had to spin faster than the speed of sound. Otherwise, nothing happened. So they couldn’t quite understand how that could spin faster than the speed of sound since the fan didn’t go at higher than the speed of sound. That is another thing I think I originated. I didn’t have a chance to write much about it, but I discovered that if you have guide vanes behind the fan, then the interaction between the fan and guide vane produces rotating pressure patterns. The interaction between guide vanes and the fan results in spinning pressure patterns that can spin faster than the speed of sound. So here, you have a wave field that spins faster than the speed of sound, and consequently couples very strongly to the waves in the duct. So I developed understanding of that theory, and I gave a talk, I remember, in the mechanical engineering department, because somebody had heard about it in the mechanical engineering department. So they asked me to give a talk on that, so I did. And in the audience was Professor Kerrebrock from the Aero Department. And he apparently liked the explanation of this phenomenon, and arranged for me to get a position in the Aero Department. So after that, my professorship was shared between the physics and the Aero Department. And I started to teach acoustics in the Aero Department, focusing on starting out with the generation of sound by rotating systems, and I talked about that in the Aero Department for several years. I supervised students, since I was probably the only one who had dealt with acoustics to any depth. Whenever there was a student with acoustic-related subjects, I ended up supervising him. So that’s how I did my work in the Aero Department.

Maling:

Very interesting. You’ve done a lot of work in computer programming and analysis over the years, including publications.

Ingard:

That’s right. As you can understand, when the first computers came out, you know, these simple ones — there are two of them up there in the closet; it’s was very heavy. Hewlett-Packard, I think, who came up with the first ones. I loved writing. It was in BASIC, I remember. The programming was in BASIC. So I quickly learned how to program in BASIC, and I wrote a lot of programs with that, and I loved to see the output come out, you know, without much labor. So I started to work with BASIC and continued with FORTRAN and C++, and I learned all these languages and bought all the computers I can get my hands on, and I still love to do that sort of thing. I wrote programs, and some people who knew about it, they asked if I could write programs for them, and that’s how it all started. I’m still writing programs.

Maling:

Any job offers or anything during your career?

Ingard:

Yes, about 30 years ago, I believe it was, I got an offer from Sweden to be a professorship in acoustics, and also being the director of the newly established acoustics laboratory at the Royal Institute of Technology in Stockholm. I considered that seriously, but the rest of the family didn’t want to go, so that ended that speculation. So we remained in this country. Then I got a similar job offer from Penn State University to lead the acoustics activity there, and so I took the family down. It was a good job with much better pay than at MIT, so it was tempting. We went down there, and even went so far as to look at land and the house market, but after having thought about it a little bit more, we decided not to go. So we remained at MIT.

Maling:

A state college is a little bit different from Cambridge, Massachusetts.

Ingard:

Exactly. This is out in the country somewhere.

Maling:

Oh, yeah. There’s a lot of country around there.

Ingard:

It’s a nice place, no doubt about that.

Maling:

No, I’ve worked with the folks and been out there quite a few times, and it’s quite nice.

Ingard:

Another thing was, at that time, my son, John, had gotten very much involved in tennis, and he went over to look at the tennis situation, and met the coach at Penn State, and after that, he said no. I’m just kidding a little bit.

Maling:

I would like to talk about the tennis a little later. But before that, how about we do professional organizations? You were involved with the Acoustical Society for a long time. Were there other professional societies that you dealt with?

Ingard:

The American Physical Society. Of course, I am a member of that. And I was a member of the Academy of Sciences in Sweden. What else? I think there is one more. I’m a member of the National Academy of Engineering in the United States. I’m also a member of the Swedish Academy of Science.

Maling:

And your publications, I know in the early days, there were a lot in the Acoustical Society Journal, but how about later on?

Ingard:

Later on, it would be in Physical Review, Physical Review Letters, Physics of Fluids, and Acoustica, and also Teknisk Tidskrift in Swedish. And of course, I subscribe to Physics Today automatically. I read that regularly.

Maling:

Yes, I do, too. Now a lot of publications and refereed journals, but do you have any other records of your research, computer programs, and notes?

Ingard:

I wrote this book. It contains a lot. Are you familiar with this book?

Maling:

No, I’m not. That’s not the one you used in the freshman physics?

Ingard:

No, that was another one. That was Ingard and Kraushaar. This summarizes my non-acoustical work.

Maling:

This is Fundamentals of Waves and Oscillations. Okay.

Ingard:

And that describes, in a simplified manner, things like the light scattering from rippled services, and many other things like that in wave theory — not only acoustic waves, but plasma waves, electromagnetic waves, and even alvian [?] waves, hydromagnetic waves. So that has been in publication for 20 years and is still selling.

Maling:

Now one thing you did in acoustics and noise control was in 1973, you were the second president of the Institute of Noise Control Engineering. Do you recall any issues in a startup organization like that?

Ingard:

Vaguely. I accepted that job after Bill Lang pushed a little hard off and on. I finally said okay. I was probably not very good as the leader of that organization, but I do remember meeting with the acoustical society people to convince them that whatever was going to be published in the technical journal — in the INCE journal — was not going to interfere much with what is going on in the Acoustical Society’s journal, and I remember having tried to convinced them that the INCE journal was going to be a lot more practical with very little mathematics. Of course, that doesn’t hold true anymore, but when they heard that, they said, “Okay, we have no objection to this thing.”

Maling:

I remember that Bruce Lindsey, who was the editor-in-chief of the Acoustical Society Journal was supportive of the new magazine, Noise Control Engineering Journal.

Ingard:

The rest of the committee was not. He was not there, Bruce Lindsey. It took a little bit of convincing to make them realize that there was nothing to fear from the publications in INCE. Of course, that has changed with time a little bit.

Maling:

It has changed with time, yeah. If you don’t mind talking a little bit about personal things, you mentioned earlier about meeting Doris and being married in Sweden. How did you happen to meet her?

Ingard:

As I mentioned earlier, I had to spend two years in military service in Stockholm, and that’s where I met Doris. I was introduced to Doris through a mutual friend of ours, and we seemed to get along very well together, and the relationship eventually developed into engagement and marriage. And I got to know her. She came from the very northern part of Sweden, and so I went up there with her several times to meet her family, and I liked it up there, and I liked what I saw, and I learned a little bit more about Doris, and that’s what happened.

Maling:

Wonderful. And how about brothers and sisters?

Ingard:

I had one sister, Asta, and she was four years older than I, and is now deceased. And on one of her vacations in Sweden, she traveled over to visit us in America and live with us for maybe a month in this country, in Belmont, Massachusetts. I was working, of course, at MIT. During that time, she met Bill Lang — William Lang. And as you know, they later got married, and she went back to Sweden, but came back again to live with Bill in this country.

Maling:

You mentioned earlier some of your activities in sports, and maybe you could tell us a little bit more about those in those early days, and then later on. I know you’ve been a tennis player for a long time. Maybe you could tell us a bit about the importance of tennis and some of your tennis partners and that sort of thing.

Ingard:

Right. Well, let me start with the track-and-field experience. When I was in the second year at Chalmers Institute of Technology, then I did a lot of competing, despite the fact that I had a high-pressure university to attend. I did a lot of competing, and I competed regularly in the academic Swedish championships, and there I usually won at least three events: 110 high hurdles, long jump, and 100-meter dash, 100-meter sprint. But then in the second year, I competed in the National Swedish Championships in Stockholm, and took second place in long jump, and as a result, became a member of the national track team in Sweden. There were two members in each event. So since I was second place, I was elected to be part of the Swedish track team. We competed with several countries. One that I remember vividly was the competition against Hungary. It was 1942, during the war, so we had to fly over Germany very low so they could control every move we made. So that was part of the agreement for us to be able to go to Hungary, which we traveled slowly over Germany. It was quite exciting. Of course, my parents didn’t want me to go because of the war. But you know, when you’re young, you don’t think about these things. I went and had a wonderful experience in Hungary. In fact, I befriended a student in Hungary whom I later corresponded with for many years, until his father was killed in a concentration camp and he had to flee to France. But I kept corresponding with him for many years. But it was a horrible period, and a very horrible experience that we had. I have many stories to tell about that, but that is probably enough for the time being.

Maling:

Okay. And how about tennis? When did you start playing tennis?

Ingard:

I didn’t start very young with tennis, because I had other interests in sports, and there was no time for anything else. But when we had moved over to this country, John, our oldest son, came home one day and said that he had played tennis with a friend of his at the town courts in Lincoln, Massachusetts, and he said it was a fantastic game. He said, “I love it.” And as a result, I managed to get permission to build a tennis court on our land in Lincoln, and did that. This started our interest in tennis. I got interested. Our children got interested. John became very good at it; he was state champion for three years in a row. He got onto the Harvard tennis team and played number one for four years at Harvard. So tennis was important to him. He also competed on school vacations — or they all did, as a matter of fact, all over the country — but John also went to Europe and played competitive tennis during his summer vacations. Marianne, our daughter, she became the Massachusetts women’s champion already when she was a junior, when she was 15 years old. So she was very good. And she later became — she was accepted to Stanford University, probably mainly because of her tennis, and played on the Stanford tennis team for four years when she was attending Stanford. The youngest son, Karl, he got a full tennis scholarship at Tulane University. He played there number one for four years. The only one who didn’t play much tennis was the second son, Sven. He was interested in other things, mainly skiing. But even if he didn’t focus on tennis, he became Mass State doubles champion one year as a junior. So tennis played a very important role for us in our family.

Maling:

And you’ve continued to play, yourself? You must have had some favorite partners over the years.

Ingard:

Yes, at MIT, my regular partners were Professor Francis Lowe and Hermann Feshbach. And up here in Maine, I played for 25 years with a retired Air Force pilot from New Hampshire. Do you know where Rye is?

Maling:

Rye, New Hampshire? Yes.

Ingard:

He lived there and drove up here two or three times a week. We have a court in the housing area here, but he lived, in fact, not too far from our house. So he came up here, and we played two or three times a week, and did that for many, many years. And when I called him to start the season this year, he couldn’t play because at the time I called him he had a blood clot.

Maling:

A blood clot, wow.

Ingard:

And also, in the wintertime, I’ve become a member of what is called Sea Course [?] Tennis Club in New Hampshire, where we also continued with this Air Force pilot during the wintertime indoors. So tennis plays a big role. And Doris and I have played; not so much anymore. But I still hit tennis balls with the grandchildren and with the children.

Maling:

Wonderful. You mentioned living in Maine, and with a court nearby. How did you end up moving to this house?

Ingard:

Well, tennis had something to do with that, too, to tell you the truth. Every summer, there was a tennis tournament in York, Maine — York Tennis Club — at the end of the season. It was sort of a fun tournament to get the players together without any pressure, because the results of that tournament didn’t count toward their state ranking. So they would come up there mainly to have fun — to meet each other and play for enjoyment. In the meantime, Doris and I looked around in York, and we fell in love with York. We tried to find a summer place in York, but anything we liked was too expensive, so we gave up the idea. But in the process, we did contact a real estate agent and two or three months later, in the middle of the winter, we got a call from this agent who said, “We have something here now that you might be interested in. Would you like to come up and look at it?” So I remember, it was the middle of the winter; there was deep snow here. We drove up, and he showed us this place — our home now. I thought it was a wonderful place, right on the ocean. I told myself, “Why don't I just take a chance on it?” So I put a down payment on the house and thought to myself that I could try to live there for a year and see if it works out, because the commute to MIT was quite long. But I didn’t tell Doris that I had done this.

Maling:

You didn’t tell her that you had purchased a house?

Ingard:

No, I didn’t, because I thought that she would object very vehemently, so I decided to wait for a while — wait two, three, four weeks until a beautiful, sunny day. Then I took her out on the ocean and said, “We own this house.” She was willing to try it for a year and see if we could manage it, and in the meantime, we rented out the house in Lincoln, because we couldn’t afford to have this house as a summerhouse. So we did, and it turned out that commuting was not too bad, and I got a system going where I prepared lectures on the way down, and utilized the time effectively, as I thought. We began to love it up here.

Maling:

And then you retired from MIT, and no more commuting?

Ingard:

Retired from MIT, and moved up here. We lived here already, but the commuting didn’t bother me, since it was very little of it. So the commuting, I learned to handle. I took a day off every week from MIT. This was my consulting day. I spent that up here. So I didn’t drive every single day to MIT. It wasn’t too bad.

Maling:

And you’ve had a productive retirement here?

Ingard:

Yes, I would say so. It was compulsory retirement when you reach the age of 70 years at that time — not so anymore, I don't think. I retired in 1991, when I was 70 years old, and my best friends at MIT — Francis Low, Felix Villares, and Tony French — they were all professors at MIT at that time, same age as I, and they also had to retire at the same time. So retirement was not much of a problem for me. And when I continued working up here, cleaning up a lot of projects that I had not been able to do — both writing and computer programming. And I did a little consulting, and I was well enough so I could drive back and forth without too much trouble. Retirement was no big problem for me.

Maling:

Very good. Is there anything I missed in this discussion?

Ingard:

I think so, but as I said earlier to you, come back in ten years, and we can discuss it again.

Maling:

Okay. Thank you very much; it’s been a great experience.