Harvey Fletcher

Knudsen:

Dr. Fletcher, I’d like to begin by asking a few questions about your family history. I understand that your father, like mine, as a small boy walked alongside of a covered wagon from Missouri to Salt Lake City.

Fletcher:

That’s right, in 1852.

Knudsen:

That happens to be 10 years earlier than my father’s trek. It may interest you to know that in Echo, Utah, my father helped bury his younger sister — my father was nine years old at that time.

Fletcher:

Well, I didn’t know that.

Knudsen:

How has this pioneer background influenced your life, either professionally or otherwise?

Fletcher:

Well, of course, I didn’t see any of it. My father did take us out into the mountains — he was still fond of it after his early pioneering experience. Sixteen times, I think he told me, he drove an ox team back to the Missouri River to get people who were coming out west. I thought that was a real sacrifice and he said, “Oh, this was great sport.” He had a great love for it.

Knudsen:

Fun was different in those days, wasn’t it?

Fletcher:

Yes, it was. Oh, he had some rather interesting stories about meeting Indians and crossing the river. It reminds me of some of the things you see now on television.

Knudsen:

Do you think this had any bearing upon the good health and vigor you’ve enjoyed through most of your life, and your youthfulness now? I won’t cite your age.

Fletcher:

Well, I don’t know whether it does or not. I’ve had pretty good health, although as a young boy I had some severe sicknesses. One time they’d thought I lost my hearing completely, but I got over it in about a month; it came back again, after some childhood sickness. I’ve had two or three major spells and three nervous breakdowns. I suppose that’s due to intellectual efforts and so forth. The last 20 years I think have been better than anything previously and I’m feeling pretty good.

Knudsen:

I guess my stomach is weaker than yours; that’s where I always broke through with perforations.

Fletcher:

I remember being on the anxious seat in Baltimore when you were in the hospital there.

Knudsen:

Dr. Fletcher, you and I went to the same grammar schools in the same city of Provo. I wonder if you would describe some of your elementary schooling.

Fletcher:

Well, let me tell you the first thing I remember in grade school. It was a little school down in Provo called Webster School, and as I bring it into my mind I can see myself sitting on one of these high stools on a table, a high table, with a big dunce cap on my head. I think I was in the first or second grade and my brother was sitting down at the bottom of the table sketching lions and tigers. He later became an artist. But they didn’t seem to reprimand him for that. I was sitting up on that for some purpose; I don’t know, I’d done something wrong. That’s my first thought of school that I can remember. And, you know, a thing like that does make an impression on a young man’s mind to have sat up there and have all the others laugh at him!

Knudsen:

May I interrupt and tell you about my first day, because this will interest you. Paul Z. Mazer, one of our great educators in Utah, and after whom my elementary school was named, was present my first day of, school and wrote a motto on the blackboard. I wish I could remember the motto, but it was encased in glass and may be there to this day. Have you ever been to the Mazer school?

Fletcher:

I’ve been there, but I don’t remember that. I went to the Parker School, so I never attended the Mazer School, but I remember where it is.

Knudsen:

Well, we must get on, I guess, here. Are there any incidents or emergent tendencies associated with these school years that led you later to choose science, and specifically physics, as your life’s work?

Fletcher:

Well, I remember one incident in the eighth grade or, I guess it was the seventh grade. A teacher told me about it long after it had happened, after I had grown up. She was teaching something to do in mathematics — I’ve forgotten just what — and I came back to her and I said, “It isn’t that way anymore, it’s this way.” it embarrassed her very much. I’d been used to arguing with my mother, and I don’t know if that had anything to do with it.

Knudsen:

You were confounding the wise in the temple. You’ve done a lot of that in your years later. When did you first become interested in physics?

Fletcher:

Well I went to high school, at the BYU, which was the only high school in Provo at that time, pretty largely because everybody else did, I suppose. I wasn’t interested in anything, but I came along to a course in physics and I treated that like I did some of the other subjects, I didn’t work at it. I didn’t hand in my laboratory journal as I was supposed to. As a result, I failed the first course in physics I ever took. And I really think that’s what oriented me toward physics, because it so provoked me that I made up my mind I’d show that fellow. You see, it was sort of a vengeance. I took it again and I got an A in it. And more than that, the next year I was asked to assist in the laboratory, and I’ve been assisting or teaching physics ever since, off and on.

Knudsen:

Were there any teachers or scientific magazines — there were some popular science magazines in those days — that had any influence on you? Any one person? For example, you influenced me a very great deal. I was wondering if there was anything like that in your life.

Fletcher:

No, I don’t believe there was any man. Nathaniel Baldwin was at the school at that time, and he was a peculiar sort of a fellow. He was the one who gave me that failure. I did so well the next time that, as I said, he put me in the laboratory, and then I went on. He left the school, and they didn’t have many good professors. I had a professor who taught me one of the courses in college physics. I was the only one in the class. He didn’t know as much about the subject as I did, so every day I would come and talk to him and he would listen. And I learned more that way than if he had talked and had me listen.

Knudsen:

So a failure in physics led to your adoption of physics as a career?

Fletcher:

That’s right. The last years I was there we had a man from Harvard who was an excellent physicist, and I think that helped orientate me. That was Chester Snow; we came up against him later.

Knudsen:

Yes, yes. He would go through a long derivation of a mathematical formula on the board, and in the end nobody understood what it was, and he’d end up by saying, “Perfectly apparent. Perfectly apparent.” And then he’d erase it before you had time to write it in your notebook.

Fletcher:

So, I should say in the case of physics it wasn’t a personality that influenced me towards it at all. The main thing, as I said, was failing that first course, plus I found that I could do physics easier and better than most subjects when I tried. Therefore, I had talent and I naturally followed up on it, because it was what I liked best and it was easiest for me to succeed in.

Knudsen:

That persisted a long time. I won’t say how many years. I wonder if you’d review the subsequent steps that really led to your conversion to physics because in high school, certainly, the decision hadn’t yet been fully made.

Fletcher:

Well, in my last year of high school I was in the laboratory. When I started in college, and in every year of college, I taught physics or mathematics. Well, naturally, that was my field, and when I finally got through college, I had one thing that I wanted to do and that was to go to Cambridge, England, where I had heard about the famous physicists. You and I know that in that early time people had to go to Europe to really be a big shot in any scientific field. But I didn’t go. A year after college I got married. And do you know why I went to Chicago? I’ll tell you the truth instead of making it up to make a nice story. I went there because my brother in-law lived there; that was the fine reason I think I went there. Well, I found some very interesting things when I got there.

Knudsen:

Did you major in physics in college?

Fletcher:

Oh, yes. As I said, I taught physics every year in college.

Knudsen:

Who taught physics at that time? Do you remember?

Fletcher:

Well, various people. Josiah E. Hickland (?) — he’s the one who sat and listened while I taught him.

Knudsen:

Oh, yes. He taught me how to pray.

Fletcher:

Well, he was a peculiar sort of a fellow, but I’ll always feel grateful that he was a good listener.

Knudsen:

Well, he’d speak sometimes too.

Fletcher:

Of course, Chester Snow came; he was an excellent teacher, well-trained.

Knudsen:

Do you remember what courses in mathematics you had from Chester Snow?

Fletcher:

I had calculus, and I had all the mathematics up to calculus, and then I had two or three courses in physics. As a matter of fact, although I had only three years of college, I found I had more physics than mathematics and had mastered it better than the graduates out in Chicago. At first, however, they wouldn’t let me into the graduate school in Chicago because my credits didn’t look too good.

Knudsen:

It might be of some interest to this record to state that Chester Snow was and the future work he did at the Bureau of Standards.

Fletcher:

He left Chicago and went to the Bureau of Standards. He was interested, more or less, in the mathematical analysis of the various measurements that he did in magnetics and related fields. He stayed there all his professional life, I think. I don’t know whether he’s still living or not. Do you know?

Knudsen:

I do not know. I haven’t seen him for a long time.

Fletcher:

I used to go visit him every little while back there.

Knudsen:

I know I was much more afraid of him than I was of you. He had a way of frightening his students into doing their best, and you more or less attracted us. Did you minor in math in college, or didn’t you have a minor?

Fletcher:

I didn’t take a minor in college as such. I did at graduate school. I had a major in physics and a minor in mathematics.

Knudsen:

You explained why you went to Chicago. I suspect there were other reasons. Did you know of the importance of Michelson and Millikan at that time?

Fletcher:

No, I’d heard about Michelson, but I’d never heard about Millikan, and I don’t think Millikan’s name was very much in the news up to that time. But, of course, Michelson was one of the seven great men that the university purchased by going out and hiring them and giving them big salaries, unheard of salaries. They gave them all of $7,000 a year, I think, which is about double what any other professors were getting.

Knudsen:

That’s right. I know we always looked with envy on those appointments. They were called to our attention on many occasions. Who were some of the other professors in Chicago at that time besides Michelson and Millikan?

Fletcher:

Carl Kinsley and H. G. Gale. You know Gale; he was there when you were there. Those were the principal ones.

Knudsen:

And in mathematics, Lund, of course, was there.

Fletcher:

Lund in mathematics, yes.

Knudsen:

I guess he’s the one, principally, that those of us in physics looked to for help. And he was always a good friend, wasn’t he?

Fletcher:

He always had time to talk in spite of the fact that he had a full schedule to teach, He played the organ — he was a master at playing the organ. I was in his home one time and he said, “Well, what would you like me to play?” We went into his music studio, about twice the size of this room. The walls were filled right to the top, from bottom to top, three walls with volumes of music. All of Beethoven’s works were there. He said, “Now, what do you want me to play?” I went over and picked out a volume, and I said, “This.” He seemed to know the whole thing. I never saw such a man. He could master all the music and perform every Sunday, and sometimes on Saturday, and then stay with his college work during the week! And then he always had time to stop and talk to you. I couldn’t quite figure it out.

Knudsen:

Is it time for me, Dr. King, to introduce a little anecdote about Lund? Probably you’ve heard this, Harvey, but it always amused me very much. He was a good organist. He even was the organist for a time, I think, in one of the neighborhood churches, probably the University Baptist Church. And he on one occasion played some Bach music at the church service. The minister apparently didn’t know a great deal about Bach music at that time, and he called Lund aside and said, “Professor Lund, it seems to me that this music is not very religious in nature. It borders almost a little on jazz, “which was just beginning to come in at that time. And Lund smiled and said, “Well, I’ll try to revise it.” The next service he played, oh, one of the most luscious love scenes from the “Barcarole,” The minister called him aside afterwards and said, “Now, that’s the kind of music I’d like to play; that had some spiritualty.” Well, he was a great fellow, I think, for all of us students there. He seemed to be half the time talking to a graduate student in the halls of Ryerson there, and everybody liked that man very, very much.

Fletcher:

He helped me quite a bit with my work on Brownian movements.

Knudsen:

In that connection, I wonder if you’d say which of the professors at Chicago contributed most to your subsequent successes as a teacher of physics, and as a research scientist in electronic and molecular physics.

Fletcher:

Well, I think Millikan did. He stimulated me to do things. But I think Lund was a good second.

King:

How did Professor Millikan stimulate you? By example, by prodding you, by showing you?

Fletcher:

Well, by his own enthusiasm in doing things. He just was head over heels. I remember one time we were working together right close to where we had 10,000 volts. We had 10 cabinets in series, and he thought I was going to put my hand right on it, like physicists do. He didn’t have it protected like an engineer would. And he said, “Look out!” And put his hand right on that thing. It flashed out and it struck him, and he went right down on his knees. And right from this position he looked up at me and said, “Harvey, for heaven’s sake, don’t tell my wife.” You might know afterwards that we got these wires up so they wouldn’t get hold of anyone.

Knudsen:

I was knocked off the stool in your laboratory once by a similar encounter. I got my arm across I don’t know how many hundreds of volts, but I know it nearly twisted my arm off.

Fletcher:

Well, ill and good has no respect of persons.

Knudsen:

You haven’t mentioned Michelson. Nearly everybody...

Fletcher:

I can tell you something about Michelson in one of his classes. Excuse me for interrupting. I’m glad you mentioned it. He was quite an austere fellow and, of course, he had a big reputation. He’d come in very formally. His classes were small; they were so hard that not many would dare take them. Well, there’d be about 8 or 10 in his classes, that was about the maximum and he’d have his notes and he’d come in and give the talk and write on the board. When he’d get stuck, he’d say, “Well, the transition from this to the next is simple and work it out.” Well, I had been forewarned of his classes, but the first three lectures I took I spent eight hours on each one of them, trying to get the notes so that they made sense.

Knudsen:

That’s about par for his course.

Fletcher:

Well, one day, after he’d been going quite a while — I was just watching it, you know, and following the relations — I noticed he’d made a mistake. And I called his attention to it and said, “It isn’t this way, Professor, is it?” Probably I didn’t put it in a very nice way. He said, “When I need your help I’ll ask for it.” I didn’t interrupt again, but this shows that although he didn’t like to be interrupted, he had the right spirit. He came to me the next day and apologized profusely. He said, “I’m very sorry that I didn’t listen to you. You were right and I was wrong.” Well, I didn’t interrupt him in class after that. That was enough for me.

Knudsen:

Well, 10 years later he was still interrupted occasionally, but don’t think he was considerate enough then to apologize the next day. I heard him give a tongue-lashing to a young fellow on one occasion. He said, “Young man, if you’ll leave me to my own resources, I think I can extricate myself from this difficulty.”

Fletcher:

He was quite a man. This might be interesting to physicists: I remember very well when Einstein’s relativity came along, just before I entered school. He just had a touch of it, and he said, “I guess since Dr. Einstein has used our experiments more or less as a basis, I’ll tell you a little thing about it. There are a lot of these new-fangled ideas coming about these days.” So, he started to try and tell us what it was all about, and he just sort of made fun of it. I guess that shouldn’t go on the record, but that’s what he said.

King:

How would you compare Michelson and Millikan as teachers?

Fletcher:

Well, Michelson was a much more profound teacher. He would give as much in one lecture as Millikan would give in a week or two weeks, and he’d expect you to work it out. Now, Millikan was a good teacher for the average student. Michelson was the one for the men who were on their toes, the brilliant ones; the others would get lost. Millikan could carry them all along, but it’d take him much longer to do it. That would be my appraisal.

King:

How about the relation between the student and the teacher in the classroom?

Fletcher:

Well, that was very good with Millikan. As I said, you couldn’t molest Michelson at all. He was not a teacher in the ordinary sense, he was a lecturer.

Knudsen:

He was quite polite in the reviews, though. That is, each week you had two lectures and a quiz.

Fletcher:

Yes, that’s right. In the reviews he expected you to ask questions, and he’d ask questions.

Knudsen:

But he put the students through a pretty rigorous test in my day. I know that if you didn’t know the answer, he could certainly embarrass you.

Fletcher:

Yes, and he didn’t use some of the modern methods in his mathematical treatment; it was more or less the old classical methods of handling everything But if you’re talking about a teacher, Millikan was a better teacher for most students.

King:

And this was because he had more of a rapport with the students?

Fletcher:

Well, he had rapport. He would write a lot out on the board in longhand. So, he’d tell you and then he’d write it out and then review it two or three times. But Michelson would go over it, and that’s it. You’d have to go home and study for six or eight hours in order to see what he said.

Knudsen:

Well, he told us right at the beginning of class, “Don’t write down any notes during the class. Listen attentively and then as soon thereafter as possible write up your notes fully.” As you say, it would take about eight hours to write up the notes for Michelson,

Fletcher:

And you’d have to write some of them, in order to know what it was about.

Knudsen:

But I thought with Millikan you could write down just about as fast as he wrote down things on the board, and your notes were pretty complete, and you didn’t have to do much except cram for examinations.

Fletcher:

Well, that’s right. But as I said, the brilliant students would get twice as much from Michelson, two or three times as much, but the average student is lost and gets nothing out of Michelson.

Knudsen:

That was my appraisal.

Fletcher:

Well, I felt very challenged — now this is complimentary to me—by Michelson, and he always stimulated me more than Millikan.

Knudsen:

Do you wish to pursue this subject further? I know there’s one subject here that is of very great interest, and, if I may, I’d like to introduce sort of a preamble to it. I have read or heard, Dr. Fletcher, various versions, three in particular, of your participation with Professor Millikan in the research at Chicago which led to the publication in 1910 of the famous paper — I think the title is — ”The Isolation and Measurement of the Electron.”^[1] Especially, I’d like to ask about the crucial step that led to the substitution of the non-evaporative oil droplets for the volatile water droplets. But may I first describe briefly these three versions that I’ve heard, because I think they may add some interest to the interview. There is, of course, the version that’s in Millikan’s autobiography, in which he records that he attended a meeting at Winnipeg, Canada, of the British Association for the Advancement of Science, and at this meeting he presented the results of his measurements on “e” by the so-called balanced water drop method. After the meeting, his account in the autobiography goes something like this — I quote two paragraphs here from the autobiography of Millikan: “Riding back to Chicago I looked out of the window of the day coach at the Manitoba Plains and suddenly said to myself, 'What a fool I’ve been to try in this crude way to eliminate the evaporation of water droplets when mankind has spent the last 300 years improving clock oils for the very purpose of obtaining a lubricant that will scarcely evaporate at all.'” Well, when Dr. Millikan met Dr. Michelson at the university laboratory, so the account in Millikan’s autobiography goes, he told Michelson, and I quote again: “I have in mind a method by which I can determine the value of the electrical charge of the universal physical constant, the electron, to one part in one thousand, or else I am no good.” Towards the end of Dr. Millikan’s autobiographical account of his oil-drop researches, we find in the following lines his summary statement of the significance of these researches, and the one reference in the account to your participation in these researches. And I quote once more, for the last time: “It Is true that I never regarded this as either the major objective or the major result of the oil-drop method, which I took to be instead the final settling of the controversy which was violently raging at that time as to the unitary nature of electricity and matter itself. Indeed, I think that by far the most direct, simple and accurate verification not only of the unitary theory of electricity, but also the Brownian movement equation, came out of the oil-drop technique,” — And this is where he pays tribute to you — ”as initiated by Harvey Fletcher and myself and as carried out with much skill and more elaboration by Fletcher in his thesis.” This is the first version I referred to, the one that is in Mil1ikan’s autobiography and, I think, the one that most of the world of physics is inclined to read and accept. It’s somewhat different from the version that I heard as a graduate student at the University of Chicago between the years of 1919 and 1922. It was in the gossip of graduate students, as they talk about these things, and the story there was simply that Dr. Millikan, during the course of his experiments with the water droplets, told Michelson about the difficulty resulting from the rapid evaporation of these water droplets. Dr. Michelson is quoted as having replied, almost in a drawling tone, “Why don’t you use oil?” Well, that’s’ the second version. The third version is the one I heard from you as your student in about 1913. It agrees so far as I remember it today with the account given in your biographical notes that you submitted to Dr. King and which Dr. King was kind enough to send on to me. I’ve read them with great care and with a great deal of interest and, I must say, with a determ1nation to hope to verify some of the facts here some time, I remember specifically your account to us, or to me, because you allowed me to work with you at the time on some of these Brownian movement experiments, and I gained more from you in those incidents than you’d ever know. Well, as I say, what I remember of these incidents agrees very well with what I have read in the autobiographical notes that you sent to Dr. King and which he transmitted to me. And I’d like to quote part of them, and maybe a little later you’d go into more detail about some of these things that are in your notes. Whether they get into this record or not, I don’t know, but it would seem to me that it would be helpful, Dr. King, if some of these was actually spoken here in Dr. Fletcher’s words. And I quote from your notes. “Just before sending in our paper on the determination of ‘e” — I believe this was in 1910 —”Professor Millikan came to our small apartment on the west side of the campus for a discussion of the two papers mentioned above, instead of publishing them both as Joint authors, he proposed that he be the author of the first one on the determination of ‘e’ and that I be the author of the second one on Brownian Movements. This would make it possible to use the second paper as my thesis. A thesis cannot be by Joint authorship. I was disappointed but agreed to this suggestion.” I quote one more paragraph here. “This accounts for the fact that although newspapers give Professor Millikan and I equal credit for this important work, the first scientific publication of it was under Millikan’s name,” Before we go on with this, it seems to me there’s a parallel. All of us, I’m sure, have seen one of the best motion pictures I think that has come out in many years, Roshomon: the tale of a woman who is raped, and whose husband is murdered, The bandit, the woman, her husband, and a passerby, who was a Japanese peasant, all saw this incident and were all witnesses in the court, Those of us who have seen the story will recall how much the personal element in the telling of an incident can influence just what’s happened. And probably some of this is in the minds of those who participated in this incident we’re talking about now, But, so far as I know, nobody has taken the trouble to examine the newspaper accounts to which you refer in your autobiographical notes that I’ve already mentioned, I hope that someone will search through these papers; the newspaper accounts may very well help to authenticate a true version of your participation with Millikan in the conduct of the oil-drop experiments. Certainly, your version should be included in the interview we are conducting today, and I wonder if you would be good enough to review some of these things that are in the autobiographical notes. I have the notes here, Dr. Fletcher, if they will be of any use to you, and I wonder if there are things that I haven’t mentioned that you would like to comment upon.

Fletcher:

Well, the first thing I should like to say is that Millikan wrote another book that came out much earlier than his autobiography. I think it was about four years after the publication of the experiments; It was called The Electron.^[2] That gives a much fairer representation of what went on. That’s in print and you can get it. I was given generously all the credit I deserved in that book. I have never read his autobiography; recently it was called to my attention. That’s one thing. Now, there are some things that occurred to my mind, when you were reading this, in connection with Louis Begeman, who was working with Millikan on the water drop apparatus. If Millikan had oil in mind before that, why didn’t he stop work with Begeman and start work with the oil drop. In fact, he had that clear that he’d been a fool all this time. I can’t quite understand that. As I told you — I think it was in these notes — I went to see Millikan with the idea that I wanted to get work on a doctor’s thesis.

Knudsen:

Was this the first time that you had brought up the subject of a doctoral dissertation with Millikan?

Fletcher:

I had mentioned it once before, and this time I had pinned him down for a date. So, I had a date. Oh, I had had quite a few conversations with Millikan, as a matter of fact; he helped me get into the graduate school. My credits wouldn’t let me in, but I went in as a special student, and the first year I said, “I can handle all of these courses, I know,” He said, “Well, if you can handle them, we’ll let you in.” Well, I made all A’s the first year, and then they put me in as a regular graduate student. So, I was indebted to him on helping me through that way, and I had many conversations with him. But I knew that this was my second year and that I had better get busy if I wanted to get through when I expected to get through.

Knudsen:

No specific subject of a dissertation...

Fletcher:

No subject. I didn’t know they were working on this problem, he and Begeman, when I went down there. But the discussion was right there, right over the microscope, I looked in and watched these little water drops, and they kept adjusting the field until they’d stand still they wouldn’t stand still very long because they kept evaporating. Then he tried the time of fall between the two cross hairs that were in there. Well, he said, “If we could just stop this evaporation.” Now, I don’t know who it was that suggested we use something else, I couldn’t swear that I suggested it, but I do know at that conversation we suggested mercury, we suggested oil, and there was another — what was it? — a chemical compound much heavier than oil that was non-volatile. And the question arose: How could we do this? They originally thought about doing it in this chamber. Millikan said, “Maybe you could do something along this line for your thesis.” I said, “Well, I’d be glad to.” And then after he got through, he said, “Why don’t you go down and try this oil-drop.” We discussed whether this would be an apparatus like they had or whether it would work out into a big apparatus that you could put together in an afternoon. The latter thing was what we decided to do.

King:

Were they talking about an atomizer at that point, or were they thinking in terms of the cloud chamber?

Fletcher:

You mean, for producing the oil drops?

King:

Right.

Fletcher:

I can’t answer that exactly, although in my mind there was nothing else that was suggested to produce these oil drops except an atomizer, because we were going to do them right out in the air. We thought that you’d use an atomizer and squirt them up in the sunlight so you could see these little oil drops. So I proceeded to go right down to the laboratory, I got a couple of plates on the ordinary stands in the laboratory, supported them without any cover on the edge, and I put a pinhole through the top. And then I went over to the corner drugstore and bought an atomizer and some oil.

Knudsen:

Do you remember what kind of oil?

Fletcher:

I don’t remember what kind of oil. I remember it wasn’t clock oil to start with. Millikan later said he wanted to get clock oil; that doesn’t evaporate so fast. He did make that suggestion. But I didn’t use clock oil at first; I just got some oil. I believe it was olive oil. But I wouldn’t be sure of that. But, anyhow, when I came back there wasn’t much to do. We had a cathetometer on the bench and we’d been using arc lights, so I just put an arc light up there and put some lenses in until I focused it so that it went through the plates. I kept the plates about that far apart, and these plates were just about that big around. That’s all there was to it. Well, it was just lucky that you could set up a thing like that and make it work. They came through there, and I’ll tell you right now, that as I sat there that was the most beautiful sight I’d ever seen. As they came through there, this atomizer just made them small enough so that they’d give you all the colors of the rainbow. You could just see a beautiful picture of fireworks in there and, of course, they were all trembling. They were so small; you could see the Brownian movement. Well, I looked at that a while. I had this switch for a thousand volts only, so I could turn it on and off. Finally, by trying it two or three times I could see that if you turned it off and on you finally got rid of them, all but one because they all had different speeds. You just keep your eye on one of them, Well, that afternoon I got the law of fall. I’d already studied it before I set this thing up. It only took me about an hour to look at the techniques that they were using in the other experiment. Well, I was so thrilled that I tried to get Millikan down there, but I couldn’t get him for two or three days. I kept doing experiments and it was obvious that with the small oil drops I got a different result than with the large ones; the law of fall that we were using was not right.

Knudsen:

Do you remember about what order of magnitude these first experiments gave you for the value of ‘e’?

Fletcher:

Well, I think that the value I got was within about 25 percent of the correct value. But it’s obvious, so far as the statistics are concerned — the whole trouble with this setup was that the oil drops would drift off sideways; you couldn’t stop the air drafts coming from the atomizer, and you couldn’t keep them very long. But you’d keep each one long enough to make six or seven trips before you’d lose it. And so, putting them in the formula without the correction to Stokes’ law, you’d get a value for ‘e’ 11 like that.

King:

Do you recall, during the conversation with Millikan and Begeman, whether you got the impression that they were somewhat discouraged with the results that they had, that they were kind of at a dead end?

Fletcher:

No, I didn’t. As I remember, they expected to get pretty good results. They first were getting these falls, and now they were getting it so they balanced it. And I think Millikan gave a paper on that when he went up to Winnepeg.^[3]

Knudsen:

Yes, That’s what the autobiography tells. I haven’t verified it.

Fletcher:

I think that’s correct. And this is after he came back. Well, I didn’t try to balance it. As a matter of fact, I didn’t think so very much about it, only that I had a grand experience that afternoon. I was waiting for Professor Millikan to see if this was something sufficiently interesting to go ahead with. When he came back he dropped Begeman completely and he worked every afternoon. You see, I’d have to say I caught his enthusiasm. He worked every afternoon for all the time I was at Chicago.

King:

He worked every afternoon with you?

Fletcher:

With me, every afternoon. I made my studies such that we worked a full afternoon for two years; we didn’t stop.

Knudsen:

And also at night occasionally? Millikan was a great night- worker when I was there.

Fletcher:

Yes, he was a prodigious worker. He made up his slowness by his hard working

King:

What happened with Begeman? Did he continue on that?

Fletcher:

Well, I think he published that finally, but he was disgruntled with Millikan, He thought I had stolen the show — that’s one thing — and he didn’t like me very much.

Knudsen:

What became of him?

Fletcher:

He graduated that year as a PhD, and he went back to teaching.

Knudsen:

I’ve never heard of him,

Fletcher:

I don’t know where he went.

King:

It was someplace out in the Midwest, I think.^[4]

Fletcher:

I had never met him before that day because I hadn’t quite got into things; this was my second year there. The first year all I did was studies. The second year I was teaching over in the School of Education, teaching general science, and I didn’t know the graduate students. I got acquainted with them, though, that year because, as I say, we were spending full time on it. Now, that’s the story as near as I know it.

King:

Well, then, when was the first time that the material was written up? Did you write it up on your own, or did he ask you to write it up?

Fletcher:

We first got the material together, and the newspaper men came over there. It came out in the newspapers in various ways, and Millikan had a good share of that. I helped somewhat on it, but it was all explained in popular style, and Millikan was a pretty good hand at that.

King:

Were these daily newspapers, or were they also weekly?

Fletcher:

No, they were all daily newspapers. One got them, and then they sort of copied from one to another.

Knudsen:

You mentioned that C. P. Steinmetz came to visit you at that time. How did Steinmetz learn about this, do you remember? Had he read it in the New York Times, for example, or in Science? Might it have been some such source as that?

Fletcher:

I don’t know if it was in Science. As I remember it — and I can’t trust my memory that long back — it was before the Science article cane out. You know, he was a free-lancer up there; he worked for nothing. They paid his expenses so that he could go and come as he pleased. He heard about it, and he held to the old theory of electricity, that it was a strain in the ether. All his work in designing dynamos and generators was based on that. Of course, the equations remained the same. But he couldn’t quite believe that this electricity had particles and was connected with matter in that way. So he came in, and he came down to see me; Millikan was busy, and I spent all morning and afternoon with him.

King:

Was he convinced?

Fletcher:

You ought to have seen that fellow. He’s a hunchback, you know. He was hunched over, looking at the microscope, his eyes glued to it. He watched them go up and down, and then all of a sudden one of them would go on and off, and then they’d suddenly change speed and sparkle up, and he with a pencil wrote these down. “Well, well,” he said, I never would have believed it! I It must be true!” And I think he’s the one who went back to General Electric and told Irving Langmuir, who then got busy and invented the vacuum tube. And H.D. Arnold was there, also, and he went back to the Bell Laboratories and invented a vacuum tube. And you know the story of what happened to that. It took them 17 years to decide there was no patent. Well, that’s the story as near as I can remember it.

Knudsen:

Tell us a little bit more about your work on the Brownian movement. I know it had a great impact on me when I learned about Brownian movements, and you even allowed me to measure the time of fall of these little oil droplets in the oil-drop experiment that you set up, your technique for measuring Brownian movement. That seemed to me to be a rather extraordinary thing, that you could determine the number of molecules in a cubic centimeter or a gram molecule by just measuring these times. That really was an extraordinary event in my life, when I learned that was possible.

Fletcher:

Well, as I told you, there were these two papers. At the time I felt that this Brownian movement paper was just as important as the one on the charge on electricity because, as I looked upon that one at the time, it had been done, first by J. J. Thomson) only it was not so spectacular, and then by C. T. R. Wilson. This was more or less repeating their work in a way. Although it was not generally thought of and known, it was more or less in the speculative stage until this came up in such a spectacular way. That’s when electronics really started.

Knudsen:

There was nothing quantitative about Brown’s^[5] work, was there? That was just qualitative.

Fletcher:

Now, this Brownian movement thing showed to me that this electron that they’d been talking about is universal because we could determine the charge in electrolysis out of the same formula that we get the charge in the air, and they’re just alike. That had never been shown before, and it seemed to me that that was quite a step. Although it has never been so considered, at that time it seemed to me like quite a fundamental truth that these electrons are fundamental constituents of all matter, no matter where it comes up, whether in electro-chemical reactions or whether it has to do with electrons on a wire, or whatever it is. But, of course, I had a lot of fun working out these statistical equations. Einstein is really the one who set them up on these Brownian movements; his equations were fundamental, but we extended them with the help of Lund so as to this particular experiment.

King:

So that Lund was really your mentor with the mathematics of this.

Fletcher:

That’s right.

King:

Was Millikan of any help in that?

Fletcher:

No, he wouldn’t understand that. No, he was no help on that score. And it was at that time that Felix Ehrenhaft was making a big pitch in Paris, saying that it’s all nonsense that the electron is a universal thing. He said he made the experiments and got different charges by a factor of nearly 10 on these little particles. So, I wrote a paper — Millikan didn’t refer to that, but that’s on record — for the Zeitschrift fur Physik counteracting everything that Ehrenhaft had said. I calculated from our measurements what the value of ‘e’ would be if you worked right forward and measured it in the ordinary way without taking into account the variations. And, of course, I showed that you’d get exactly what he got. You might get a ratio of 10 over your charge, because these things are jumping around and sometimes they go fast and sometimes they go slow. Unless you took a complete and long series to get the average, you wouldn’t get a value of ‘e’ from them at all.

King:

What gave you the clue to go into the matter of analyzing these Brownian motions?

Fletcher:

The clue was the first experiment that I saw. I had never been introduced to Brownian movement before, and I saw those droplets jumping around and I knew — I had read it in a book — that the molecular motions would show them in liquids. But these were much more spectacular in the air, much larger, and that captivated me more than the question of getting a charge on the electron. That’s what got me into it.

King:

Did you see any Brownian motions in the experiments of Millikan and Begeman?

Fletcher:

No, you couldn’t. The drops were usually too large, and they only kept them there for a short time. I didn’t notice them. Maybe they should show on the smaller drops, but if you get them too small, they go out of the picture so quickly. But you get a lot of those tiny little blue ones in these oil drops and, boy, they hop around! To see that for the first time is quite a thrilling thing. It was for me.

Knudsen:

Seeing it more than 10 years later was a great thrill to me.

Fletcher:

Well, anymore?

Knudsen:

Yes, there’s quite a bit here yet. Would you tell us a little about the work you continued on Brownian movements? Was the paper on Ehrenhaft’s work done at Brigham Young or at the University of Chicago?

Fletcher:

Most of it was done in Chicago, but I continued it when I came back to the BYU where I worked on some phases of it.

Knudsen:

But most of your work, when you came to the Brigham Young University, was on Brownian movement?

Fletcher:

No, I would say I did it on both. One of the troubles that we had on this experiment was the uncertainty in the co-efficient of viscosity and on the slip on the oil drops. Millikan and his co-workers there worked on that for five years after I left. When I left I tried to figure out a way to get a value of ‘e’ without using the viscosity co-efficient, and that was one of the things, besides extending the Brownian movements that I worked on at the BYU. I designed the lower plate with a section in it, so that I could turn it part positive and part negative, I think you may remember that. So that if the droplet started to drift out, I could pull it back in. And then I also designed the set-up so that I could get the number of charges that are produced. After measuring the vibration, I’d suddenly put a field on and drive the droplets to a ring, measuring the amount of charge they come down at. That way I’d get an idea of the number that was in there. I could get the charge, and the actual question of the viscosity would go out of the picture. But the trouble there was statistics, you see. That depends on count and the probability of how many droplets were in there. And that’s how I went into this long calculation that I was on for two or three years, trying to get the statistics so that I was more certain how many would come down to that plate. And I never could get that accuracy any greater than the loss of accuracy due to having an uncertain viscosity co-efficient.

Knudsen:

Dr. King, I’d like to have Dr. Fetcher include something in the record here. I think it’s useful in connection with what could be done at small colleges. How many hours a week did you teach when you were at the Brigham Young University, when you were doing this Brownian research? My guess would be 20 or 24.

Fletcher:

I think that’s about right.

Knudsen:

You know, I’m afraid most young physicists starting out today, with a teaching program of 20 or 24 hours a week, would say, “Well, there’s utterly no time left for research, after you prepare your lectures, read your reports from your classes, conduct the examinations, and so on.” Yet, Dr. Fletcher in these years was doing some outstanding research both on the measurement of ‘e’ and on the Brownian movement. How did you do it?

Fletcher:

I think it’s very simple. Anyone who wants to do research can do it regardless of how much other work they’ve got. It depends on how much the urge is. I’ve said that even when I’ve been in the position of a dean and so forth. It was obvious to me then that anybody can do research, whether they’ve got 10 or 20 hours, if they want to do it. It’s a question of having that urge. I found that was true at the Bell Telephone Laboratories, even when I was an executive; if I wanted to do research I could get at it.

Knudsen:

You didn’t have much machine-shop help to get the equipment going at Brigham Young.

Fletcher:

No, we didn’t. Well, it’s a question of doing it. That doesn’t say that we shouldn’t plan to make it easier to have more research work done, but I’m sure that anyone who has really got the urge and the ability to do research can do it no matter where he is or what the situation is. Now, that may be kind of a broad statement, but I really believe that.

King:

I wonder if we could go back for a minute, I’d like to go back to the incident where Millikan came and visited you in your apartment. Did he call up and say I’m coming over to see you about something?

Fletcher:

That’s right, I remember it very well because my wife was away, and normally I would have gone to see him, but I said, “I can’t leave. I’m here with the baby” — my first baby was then born. And he said, “Well, I’ll come over there.” “Well,” I said, “okay.” So, that’s how that happened.

King:

Was this the first time he had visited you at your home?

Fletcher:

That was the first time he had ever been in my apartment. I’d been in his two or three times, to dinner and parties, and so forth.

King:

And how did he bring up the conversation?

Fletcher:

Well, it was straight forward. He said, “You know you want a thesis. That’s what you came to me for originally, for your doctor’s thesis. And you’ve got to have it on one name. We’ve got these two pieces of research: the Brownian movement and this work we’ve done together. Do you object if I publish this one and let you publish that one?” Well, I didn’t jump at it, but I accepted it.

Knudsen:

Except that he told you; he didn’t ask you.

Fletcher:

Well, it wasn’t quite that way either. It was done in a nice way. As I look back on it now, it made quite a bit of difference, but as I looked on it then, it didn’t seem to me that it did. It seemed to me that both of these were about equal in contribution, like the physicists in America thought about sending Sputnik up: “We’ve known how to do that for years. Why bother about it?” Look at the repercussion it had when the Russians did it first, it practically took a third of the world away from us. Well, now, as I say, that didn’t seem to me a big thing at that time, and I appreciated very much the publicity I’d already had, I never had my name in the newspaper, and here it was in several places for the past two or three months. So, in my mind it seemed all right. I’m not saying this for any other reason, only to get the facts, and since you’re interested in history, I’m putting it there and will let it stay there. When I’m gone, then I won’t even worry about it.

King:

Did he stay much longer after he had brought up this matter of the experiment and your thesis?

Fletcher:

Oh, he went over some of it. We went over some of the things in the paper.

King:

It was a paper in Science?*

Fletcher:

This was the paper in Science. I think I wrote about two thirds of it, all the part that had to do with the change in the law of fall, Stokes’ Law — I’d done all that work.

King:

This was in addition to the previous work, wasn’t it? This hadn’t been brought up before, had it — the problem of the modification of Stokes’ Law?

Fletcher:

No. The things that had been in the newspaper were told in a popular way, talking about the discovery of the fact that electricity is atomic and how they measured the amount of charge on it. All that sort of thing sounds very good to the public.

King:

No, I was thinking in terms of the correction of Stokes’ Law. Was this your work or was it Millikan’s work?

Fletcher:

This was in the paper in Science.

King:

And who contributed that?

Fletcher:

Well, who contributed it? I think I did most of the writing of it but — well, I’d been studying the thing after we’d run into this difficulty. We’d been plotting ‘e’ versus the radius; the radius of the little droplet, or A, over L, the mean-free-path. And we’d get a curve. Then I said to Millikan one day, “What fool s we are. Why don’t we take two-thirds of that and there’ll be a straight line?” He kind of looked funny. And after that we did that. I’d read all the works that had been written on this law of fall, so I was pretty well familiar with it, and how it is related to the mean free path as you change the pressure. And we had actually begun working with an enclosed chamber. Oh, I didn’t tell you that. After he saw the haywire setup that first day, he brought in his people from the shop, and we made a really good setup. And we made it, finally, so that we could change the pressure in there. And then, of course, you made your mean free path quite a bit longer; and it was the ratio of L to A that comes in on the modification of Stokes’ Law. That part we put in the paper because that was fundamental. You had to project on a straight line the value of A until it hit the axis, and that would give the actual value; that’s the way you had to do it all the time. And because of that, as I say, the next five years we had students working on this viscosity, measuring it by vibrating cylinders and rotating it in several different ways, because that was the thing that determined the accuracy.

King:

Let me ask you this rather personal question — perhaps you wouldn’t care to answer it — but do you feel any bitterness towards Millikan?

Fletcher:

None whatever, no. No, I don’t, Millikan was very good to me and, as a matter of fact, as I said, I had a lot of credit, and I got a summa cum laude when I graduated.

Knudsen:

I think there were only two at the time I was there, 10 years later. Isn’t that right? You and Dempster?

Fletcher:

I was the first one.

Knudsen:

You were the first one to get a summa cum laude. They don’t hand out many of them around there.

Fletcher:

And I think t Millikan was largely responsible. He was a key man on that, noting my research. I did have a fine time on my doctor’s examination. The day before when the poor fellow came up there, they just plastered him. My examination lasted all day. I had it in the morning and in the afternoon, with lunch in between. But the one who was before me, they failed him, and that got me all excited. His family was there for graduation, and then he flunked his exam. Well, anyhow, I sort of felt that I knew the stuff pretty well, and I did, and they had the jury there from the various departments. They examined us on all 27 majors at once. And that’s quite an ordeal. But I just seemed to be on my mettle at that time, and I went to it, and I think 1 got through all their questions. They kept asking, as they usually did, until you couldn’t go any further in the field. And I did make a good showing that day. But I think they should never do that to a person. I fell down towards the end and had to have two fellows carry me home just about. You didn’t realize how much had gone out of you until you got through.

Knudsen:

Today this is distributed over two or three years sometimes. You know, advancement to candidacy and then examinations in this field, and then you prepare for examinations in the next field, and so on; it’s a sequential thing. There are probably five or six examinations over a period of 2 years. In Chicago, 10 years later when I was there, everything was this one big examination. You were examined on all your courses, on your dissertation, everything. And everybody from the Department of Physics to the Department of Mathematics might be there to conduct the examination. Is that the way it was?

Fletcher:

Yes, that’s the way it was. The only trouble is that I was there all day and they’d come in two hours at a time!

Knudsen:

Well, Dr. King, the one thing I would like to add to the record here that I think is of some historical significance and is a matter that I’ve discussed with colleagues both in electronic physics and in acoustics. Dr. Fletcher probably shouldn’t hear this because it may be a little embarrassing to him, but there are two accomplishments of Dr. Fletcher that came very close to a Nobel Prize; that is, certainly the work he did with Millikan on the oil-drop experiments, for the charge on the electron and the Brownian movement. With a little change of circumstances, possibly the Nobel Prize would have been divided. I think that it’s only fair as an observing physicist and one who knows Fletcher very well and knows Millikan very well to say that for the record, and I say it sobriety and with no fear of contradiction because these things, of course, are decided by committees and often choices are very, very close, as we know in life. The other incident has to do with some experiments we’re going to talk with Dr. Fletcher about a little later, but maybe this will give him a little rest when we come up to this next subject. Two or three years ago Dr. Von Békésy won the Nobel Prize.^[6] It was the first time anyone in the field of acoustics had won a Nobel Prize, and it was for work that was very closely related to the kind of work that we’re going to ask Dr. Fletcher about a little later, his work on hearing, his work on loudness, his work on the nature of cochlear dynamics, and things of that sort. Those of us who know the total record of the work that has been done recognize that in these as in other incidents it’s not the work of one man alone; it’s the work of a number of men. And if the Nobel Prize for the work in hearing, for example, had been shared, certainly the person with whom it would have been shared would have been Harvey Fletcher. I wanted to say that much for the record. I haven’t rehearsed this. I hadn’t planned to do it, but as we were conversing here, I would have felt that I would have been remiss if I hadn’t added this much.

Fletcher:

Well, I appreciate that. You might be interested in an incident Millikan told me. He said he had been over to England and had met H. A. Lorentz. Lorentz wrote one of the early books on electron theory. It came out about 1910, I think. And they introduced Millikan to him and he said, “Oh, you’re the man that worked with Fletcher on the determination of ‘e’!”

King:

Did Millikan enjoy that?

Fletcher:

Well, he told it to me!

Knudsen:

I want to begin next with the circumstances that led to your leaving teaching at the Brigham Young University to go to the Industrial Research Laboratory at Western Electric. I think that would be of some interest in the historical record.

Fletcher:

Well, BYU was a small school. I enjoyed the few students I had there, and they all made a good record, Vern

Knudsen:

was one of them.

Knudsen:

Name some of the others.

Fletcher:

Vern was a chancellor. And there was a college president, Ray Olfin. And I think there are three deans out of the class. We had only about 10 or 15 in physics. The reason I went to Western Electric was because, I suppose, I was ambitious, if you want the truth. I was anxious to try something against the best of them. I think that would be a true statement as to why I went there; it was challenging. And I might say it wasn’t because I hadn’t been persuaded, because F. B. Jewett threw every bit of persuasion that he could think of to get me there from Chicago. He was the president of the laboratory. They had in mind the making of a vacuum tube or an equivalent device, and they thought I had the best inside track of anyone. I said, “No, I promised BYU that I’d go back there, and I’m going back there. And Jewett called me every year for five years, always with the same question: “Which is uppermost in your mind this year? Sentiment or money?” And in the last year he got me to come. Does that story answer your question?

Knudsen:

That’s a good answer. I think that certainly handles it. If my memory is correct, and it often is not, was the first subject you investigated at the Bell Telephone Laboratories the howling telephone?

Fletcher:

Well, I think that’s about the first one I wrote about. I don’t know why I called it the “howling telephone.” But they had trouble with the feedback that’s what they call it now and I wrote a paper on that.

Knudsen:

What got you strictly into acoustics at the Bell Laboratories?

Fletcher:

Well, now, I can tell you about that. They wanted me to go into radio. Some of the friends I knew at Chicago were there, and they said, “You just don’t want to lose yourself in something else. This radio is going to be the big thing.” They’d just completed these tests overseas, you know, going from Arlington over to the Eiffel Tower. And they’d had half of the laboratory scattered over the world trying to pick it up at various places. And that was about three years after the vacuum tube was invented.

Knudsen:

You went to the Laboratories in 1916?

Fletcher:

1916. Well, I considered that, and then they wanted me to go over to what they called transmission research. And the war came on in 1918, you see, and by 1919 half of the supervisors were tied up in one way or another. What year did you come?

Knudsen:

1918.

Fletcher:

Well, then O.E. Buckley was called into service soon after that, wasn’t he?

Knudsen:

Yes, that’s right.

Fletcher:

So, I was left alone to do my own work and my own planning and my own thinking, And, of course, we got into underwater sound in that early day, and I was out there fussing around with little gadgets, I did make an undersea microphone and it worked, but it was never used. So, that’s when I first got Interested in sound. Then after the war it was decided to have a conference with the AT&T Co. and go over the whole field of articulation tests and how sound is related to the telephone business. I got into those conferences, and I.B. Crandall and I sat down for about six months and wrote up a plan of operations to go on forever, on what the laboratory should do in this field. Crandall was in a different group than I was, but we cooperated and we also held the conference with Martin downtown. We got this out, and when the bosses came back, we presented it and said, “Now, here’s the kind of a program that we thought we ought to go ahead with.” Well, it so happened, unluckily, that Crandall up and died about that time, and the whole program was thrown into my lap, and that’s practically what I carried on the rest of my time in the laboratory, the directing of the program. It was studying the voice and how it’s related to the design of the microphone, studying hearing, and how it’s related to the reception of speech, and what goes on in the line and how can you measure the value of it in terms of how well people understand each other. It was that kind of a problem. We divided it up. The first part of the program was to try, along with making these studies, to make a telephone system so that you couldn’t tell the difference whether you were talking six feet apart or whether you were talking with the instrument on your ear. That was objective one. The second objective was to make a set that you could project through the loudspeaker, so that you couldn’t tell the difference whether it was a person speaking on a stage or whether you were getting it through the loudspeaker. At that time, as you know, loudspeakers were terrible. Now, on this first objective we worked, oh, close to 10 years and didn’t seem to get anywhere. First of all, we had to make new micro phones and new receivers, because they were testing receivers down out here where they manufacture them — one man on one end and another man on the other: “Now, we’re off on this one, Now we’re off on that one,” and they’d switch from one to the other, and the fellow on the other end would listen and say which ones were good and which were bad. And it turned out that with that kind of technique the more resonant they would make it, the louder they would get it at the other end with the same thing and, consequently, the system got worse and worse because they got more and more peaked, both the transmitters and the receivers. But we were cut loose in the research to make new microphones and to make new transmitters, and that’s when the first condenser microphone was made by E.C. Wente. He was in this group, my group. And also that was the first one they used in motion pictures because that was the only one that would give a fairly good response. Then they went to work and built receivers, Well, when we got the transmitters and receivers, then we knew how to draw the lines. We by that time were familiar with the technique on amplifiers and that didn’t give us too much trouble. But after we got all that done, it wasn’t right. It took us 10 years to tell them that we listen with two ears! Then, we got the two ears in there, the two channels, it just gave perfect transference and that’s what we had at the World’s Fair in 1933. You may remember the Oscar Show there. It still startles people any time they listen to that kind of a system.

Knudsen:

There are probably about 15 or 20 papers that I’d like to question you about, if we had several days, but I can only ask you about two or three. Tell us something about the Fletcher-Munson equal loudness curves that everybody associates with your name.^[7] W. A, Munson was one of our students here, so we won’t belittle his part. We hope to have him back here sometime.

Fletcher:

Well, during our general study on tones and on loudness, it occurred to me that we had a good measure of pitch; we knew how to measure frequency and we knew how to measure amplitude and intensity. But to talk about loudness and then have double 40 and two F’s and one F and pianissimo, and that’s about all we know, so why can’t we do this on a scale. So, we thought the first thing to do was to measure the loudness of pure tones. At that time, we just had finished a booth that was walled in on three sides — well two sides were open — and it was a pretty good place to listen, because it was quiet. So we started in to make these measurements. We used a receiver for the tones, however. And I think we were surprised, as a lot of people were, to find that they didn’t follow the intensity. With the intensity the low frequencies, of course, were much louder, that is, they increased in loudness much faster than the high frequency tones. Well, that’s where we made those curves, it wasn’t because we were thinking they would be valuable for making radios, or anything of that sort; we were just interested in it.

Knudsen:

Perhaps, historically, it would be more interesting to ask what led to the critical band width which you discovered.^[8]

Fletcher:

Most of these discoveries are group things, but I think the critical band width I was responsible for. They’d done all the experimental work and I didn’t get into it until I saw the reports, and they didn’t get on to the fact that in here was something that was very unique. I began experimenting at my desk and I found out that these band widths were critical, and then we were able to go and try the other types of experiments by measuring the band width. But I first found it in the case of masking, where you’d take a filter and make the band smaller and smaller in width, and as near as we could make the measurements, they’ve checked the others. There’s a certain critical band that won’t do any more masking if you widen it beyond a certain point, and when you get it down to that point and narrow it, then it begins to do less and less masking. That’s going to be the basis also of what I’m going to talk about this afternoon. There’s something in the air that corresponds to that critical frequency, and it looks to me like it’s a width which is equal to the width of the basilar membrane. Because, as you see, as you get narrower and narrower, the actual adjacent vibrations influence the narrow ones more than the end vibrations, and when you get it out wide, these end elasticity’s are the ones that control it, and then you get it about equal to the width, and then that begins to vibrate as a whole.

Knudsen:

I think it would be appropriate to ask you something about the subject that you alluded to, that it took 10 years really to recognize the importance of binaural hearing. And that, of course, led to this entire subject of stereophonic sound, which is a very important thing. I presume many people have been influenced by your early experiments in stereophonic sound. I witnessed the first demonstration which you and Stokowski conducted, transmitting from Philadelphia to Constitution Hall in Washington, and I know something of the impact that had. Give us a little of the background there, and then we’ll bring this to a close quite soon.

Fletcher:

Well, of course, that was also a group project. We thought if we could produce in front of a stage, as in a theater, a sheet of sound which was the same that would have been produced were someone on there the audience ought to get the same effect as though the actors were on the stage. Well, originally we thought of a sheet of sound where we’d have a lot of loudspeakers. Thus, in our original demonstration, we had to design loudspeakers, microphones and amplifiers. You remember these were in the days when you couldn’t go down to the store and buy them. And to witness the fact that we thought in terms of vertical as well as horizontal, we built nine loudspeakers, three up and three across. I was just talking to Seritt, and he’s got three of them down there in his lab and I’ve got four in our lab now, and that accounts for seven of them, I don’t know where the other two are.

Knudsen:

I think the other two are being sent to you. Someone at Bell Laboratories said they were sending you two…

Fletcher:

They’re sending me two, and that’ll make four.

Knudsen:

I see. So there are two missing.

Fletcher:

Two somewhere else. And so, the question of these nine loudspeakers has grown up to the idea that you ought to have at least two. It’s turned down to about two now. But that was the starting of it, and then we started to go to work and implement that to see if it was right.

Knudsen:

How did you find out that the vertical was not as important as the horizontal?

Fletcher:

Well, we were just dumb enough not to realize that on the stage people don’t jump up and down.

Knudsen:

Sometimes an orchestra and a chorus do that.

Fletcher:

Yes, and I was thinking for something like Hamlet’s ghost, it would be alright to have the speakers run up arid down. That’s about all there was to that. The conception was very simple but, boy, I think it cost us a hundred thousand dollars to implement that! We had to make everything, especially when we gave that demonstration between Philadelphia and Washington. You didn’t see that one.

Knudsen:

I did. I was in Constitution Hall, listening there.

Fletcher:

Well, then you got the thrill I did. I was in it and sort of conducting it, but I still was thrilled with that music.

Knudsen:

I also was present when you gave your demonstration at Rochester. You demonstrated that you were a good showman also on that occasion. Tell us briefly about the experiments you conducted there with the string quartet playing the “Andante Cantabile of Tschalkowsky. You had the audience vote on which was the original and which was the recorded.

Fletcher:

Yes, we took that orchestra up there and had them record it stereophonically. And then part of the time we played the real orchestra and part of the time we played the reproduction, and then we asked the audience to vote, and they split right in two!

Knudsen:

Half of them said the first part was the original and the other half said the second part. That has an interesting bearing, of course, on psycho-acoustics.

Fletcher:

We felt, after those experiments, that we knew how to reproduce sound so that it was, as judged by the ear, as perfect as it comes, and we thought we could make it better.

Knudsen:

Your right-hand man out there, Bill Snow, is in Santa Monica now. We see a great deal of him, and we learned a great deal second hand about this whole stereophonic field through him.

Fletcher:

Well, the strange thing about it is that it was 23 years after those experiments before the public got wise that there was something in it that was entertaining.

Knudsen:

Was Walt Disney the first really to make use of it?

Fletcher:

Well, he had hired the Philadelphia Orchestra — it covered the same period that we were making our experiment. They caught on to what we were doing, and Walt Disney begged us to put on the stereophonic for his pictures. The Bell System said no; they were going to demonstrate this for the public, and they weren’t going to use it for a commercial venture. Well, they didn’t want to tie it up in any way like that, that would have gotten them into trouble, I think. So, they went to work and made a makeshift out of it, and that’s what started that Stokowski picture.

Knudsen:

I’d like to ask you about another thing. We’re rambling here, and we haven’t much more time. Won’t you tell us a little about your role in the founding of the Acoustical Society of America?

Fletcher:

Well, you’re asking me that so as to get it on record. You know as much about it as I do because you’re interested in it, too. I think the man that really started the thing was Wallace Waterfall. He was a young fellow, who was testing acoustical materials, and he finally got some of the PhD. Interested — you might put it that way. And I became very much interested in it at the Bell Laboratories, simply because I had been frustrated in trying to read some published papers before the American Physical Society. When I did, they would publish them, and give a report on the program, but nobody seemed to be interested; nobody would listen to them. So that came about, and there were a few insurgents around like Dr.

Knudsen:

I’m sure he was for it. If I call you an insurgent, you won’t mind, will you?

Knudsen:

No, I’ve been called worse things than that. The organizational meeting took place at the Bell Telephone Laboratories, and there was no question about who should be the first President of the Acoustical Society. The unanimous choice was Harvey Fletcher.

Fletcher:

The reason for that being that the meeting was held at the Bell Laboratory and I was the host, more or less, for the crowd, and they put me in as temporary chairman.

Knudsen:

I think he would have been made President even if it were held in Los Angeles.

King:

Actually, there didn’t seem to be much place in the Physical Society for work on acoustics. Now, is this correct?

Fletcher:

Well, that’s what we thought. It was the same thing that took the Optical Society out. Later on, we decided the only thing to do to hold things together was to make sections on these various fields, in which the interested men would stay in a group and discuss among themselves, instead of being encumbered by a lot of people that weren’t interested.

King:

But yet you founded your own organization rather than a section in the Physical Society.

Fletcher:

That’s right, and the Physical Society is pretty well peeved for that move. And at the meeting that Vern refers to, we had both sides, the conservatives and the insurgents. Some of them wanted to pull away and some thought we ought to stay in the Physical Society. They finally decided to form an organization of their own. Then the Audio Engineering Society pulled out of the Acoustical Society! Now, they’re a bigger organization than the Acoustical Society, aren’t they? I believe they are.

Knudsen:

As big, I guess. I don’t know.

King:

How about the institute of Radio Engineers? Would it have been possible for the men who were interested in publishing papers on the relation between acoustics and electronics to find a proper place for publication in the IRE?

Fletcher:

Yes. A lot of papers were published there. I gave two or three papers there by invitation. But there’re back now together with the American Institute of Electrical Engineers. I don’t know whether the Physical Society will gobble up all these societies like that or not.

King:

I was wondering that since so many men who founded the Acoustical Society were at the Bell Labs, and they had this double background, why perhaps this organization did not grow up within the IRE. Why didn’t they find a home in the IRE?

Fletcher:

Well, as you say, there were a lot of people in the IRE; that’s more or less where it started, in the Bell Laboratory.

Knudsen:

I think Dr. Fletcher put his finger on a very significant thing. A very important person, Wallace Waterfall — maybe he’d gone some other place but first, I think, he talked with you — went to the West Coast and talked with Professor F. R. Watson and myself. And he talked with a few people like that, all of whom felt that it would be very, very much better if we could have an organization where a hundred percent of the people were interested in what you were talking about rather than two or three percent. I don’t imagine more than two or three percent of the people we were addressing, when we presented papers at the meetings of the Physical Society, were interested in what we were talking about; they were interested in something else. And so, this turned out to be a field of interest. Of course, it includes many branches and many disciplines now.

Fletcher:

A lot of people in the Acoustical Society would never think of being in the IRE; they couldn’t be elected, wouldn’t have the background. So, that’s the way these things get started.

Knudsen:

Do you have any other questions you’d like to ask?

King:

Yes, I’d like to raise the question of the audiometer. What were some of the steps that led to the development of the audiometer?

Fletcher:

Well, I think the first audiometer that I’d seen was made by Professor C. E. Seashore. He was a psychologist and Dean of the graduate school at the University of Iowa. But he only used it to test variations in normal hearing. It was simply a little buzzer with a rheostat on it, and it measured in terms of resistance. As far as I know, that was the first one. About the same time, someone down at that same school made one for the Bell Laboratory out of vacuum-tube oscillators. Who was that?

Knudsen:

L. W. Dean and C. C. Bunch.

Fletcher:

That’s right. And that’s about the same time you came and started making audiometers.

Knudsen:

Oh, a little later. Dean was, I think, an otologist, and Bunch was, I believe, a psychologist.

Fletcher:

Well, we had conferences with the doctors, and it was obvious that they had a pretty clumsy scale, using tuning forks. We got into it at the Bell Laboratories because the big bosses kept referring some of their friends, “Can’t you do something for this fellow?” So we tried to fix up something, and that’s when we started to learn how to use oscillators and attenuators for measuring hearing. And then it looked like there was a need, and we doubled up with Dr. Fowler, who gave us, oh, some of the problems of hearing. But mainly we used Dr. Fowler; he was quite a prominent otologist, to help get this thing started. And then they gave some papers on this before the otologists. I think Vern and someone were working on this thing at the same time.

Knudsen:

Yes, Isaac Jones, the otologist. He wanted an audiometer especially so he could test speech. So, really, the thing we were interested in was having an instrument with which you would test hearing loss not only by measuring the loss at different tones, but also by getting a composite measure of how much loss there is for speech.

Fletcher:

Well, it was obvious that they needed something, rather than just playing around in the laboratory trying to build something. And so, I took the initiative there at the Laboratory of designing a simple what they call the 4A audiometer. I designed it so that it was as free from defects as possible and got it out on the market to sell it. Then I went out and told the doctors how to handle it safely, and that’s how that got started. That seemed to be the standard until the last war, and then they started to make these things all over because Western Electric and the telephone business decided that they didn’t want to be in competition with their competitors, and they want out of the motion picture business, the loudspeaker business, the audiometer business, hearing aids — They went out of all of them. But the last time I knew, the old 4A audiometer curve is still in use at the Bureau of Standards. They’ve tried for 20 years to get a standard, and they can’t get anyone to agree to it. So there isn’t any standard really except the original receivers of the old 4A audiometer, as far as I know.

Knudsen:

The U. S. standard now differs considerably from the European, and the problem now is whether we’re going to have an international standard. That’s a hot subject at the present time.

Fletcher:

Well, it’s hot at the present time and it was hot 20 years ago.

Knudsen:

Well, to go on now, tell us a little about your present research interests.

Fletcher:

Well, at the present time I’m interested in research in music, and here is the problem: to try to re-create any musical tone. We’ve got records of all the musical instruments in an orchestra. First we tried the piano, and then the organ, and now we’re working on the violin and the other stringed instruments and the flute. People have analyzed these tones, of course, before. Usually when they talk about analysis, it’s to get the partial analysis of the tone. But there’s a lot to these musical tones besides finding out their harmonic content or their partial content; for example, the amount of noise they create in playing, the steadiness of the pitch, and the attack and the decay. Now, all of that has been worked on before, but here is the new slant, as far as I can see. We take this analysis and then put it into a synthesizer and put these things in individually instead of just putting a recording in, where you get everything together. We put in the noise separately, and all the components separately, and produce a synthetic tone. And after doing that you present the tones to a jury of musicians and laymen and let them identify them by actual test. Let them pick out the ones that are real from the ones that are synthetic, until we can make it so that they can’t tell the difference, so it’s a 50-50 choice, And that’s a very critical test, as anyone who’s done any work knows it is, because when you make them so that you can’t tell the difference, you then can pretty well be sure that you’ve got the characteristics. Well, what we’ve done first is the piano, and of course we ran into the question of a piano as an instrument where you don’t get any harmonics. That’s an old story but somewhat new to us. But piano makers have been, I think, designing pianos with the idea to make what they call the non-harmonicity of the pianos as small as possible. It turns out from the formulas that if you make the string long the actual partial tones are nearly harmonic. And if you can make it long enough, they’d be exactly harmonic. Now, if they could make a piano that way, it would be lovely. We actually made a synthetic tone — you can make it exactly harmonic, make the attack exactly the same as on the piano end the decay the same, the harmonic structure the same. We did that, along with some other things, and all of them say, “Why that’s not a piano tone at all; it’s an organ tone.” They wouldn’t have it. They said, “Well, If you want to play an organ with a piano attack and decay, why that’s another Instrument, but the quality of a piano depends upon its being non-harmonic. If you change it from that, it’s no longer of piano quality.” That’s the sort of thing we ran into first.

Knudsen:

And this is the problem of the well-tempered clavichord.

Fletcher:

Well, I don’t know if it’s a problem. But you run into a lot of things when you get into the violin, for example. What is a vibrato? Well, we’ve always been told that it’s a change in the pitch. But is it a change in intensity or pitch? Actually, it’s both. We’ve developed a technique for separating the two. I don’t know where we’re going, but I expect we’ll be able to tell more about the violin, because when you get right near one of these resonances in the body of the violin, the actual vibrato or the intensity go way up because, you see, you go in and out that resonance. When you get away from it, the intensity of the vibrato is way down. I believe there’s a better way to test the body of a violin than the way they’ve been doing for 20 years. Well, we’re right in the middle of that now. We’re going through all the instruments in the same way. In the case of the organ, I think we’ve shown just why it is that the electronic organs don’t equal the pipe organ. It can be made to be equal and better than the pipe organ, but they never do it. They build them for a price rather than for the effect,

Knudsen:

It’s a nice example of how research keeps a man young. One more brief question about your accomplishments. After most people you established a School of Engineering at the BYU. Just in two or three sentences tell us about it,

Fletcher:

Well, in two or three sentences, I went there and swore I’d never take another executive Job. I went there to sort of direct research and show them how to get some funds so that they could get a more extensive research program going. After I was there about, oh, two months, they had started someone on engineering, and the president came to me and said, “Now, we’ll never get an engineering school unless you come and start it and do it.” Here I am back again. So, we started it, got the thing going, and got it accredited. I was with it about seven years. I got a man to take care of it. Now I’m through with it. It’s a pretty good engineering school, by the way.

Knudsen:

Yes, it’s of high quality. I hear very good reports about it. One more question, I think. This is, perhaps, the most important contribution of all you’ve made, and that’s your own children. I know them.

Fletcher:

My wife made more of a contribution than I.

Knudsen:

Well, this is just among us men, I know that, but we mustn’t tell too much about that. But four of five boys that Dr. Fletcher has, I know, are in physics, in very closely associated things, and the other is in engineering. One, Jim, has just been named President of the University of Utah. Tell us, how did four out of five follow in your footsteps?

Fletcher:

You see, we haven’t time to talk, and then you get me talking about the children. I didn’t orientate them towards physics. Some people think that, but it’s a natural thing for children to see what their fathers are doing, if they’re boys particularly. The reason that the four of them went into that field is not because I was a physicist, but because they found they were very competent, the same as I found, in that field. And, therefore, they liked it best and it was easier to go into it. I think it’s very lucky that they had the inclination, all of them, to go ahead and get their doctorates, and make distinction in their studies.

Knudsen:

Tell us what each of them is doing now.

Fletcher:

Steve is the oldest. You’d naturally think that he’d lead the crowd and they’d follow, but he’s a lawyer. He went into law and decided he was going to be a lawyer when he was in second-year high school, very, very early. And so, he got into the law business. He graduated from Columbia with his Bachelor’s degree and then he went on to Law School, and he was almost a youngster when he got started in law. I guess it was two years before he got married — he was through college, three years in law and two years in practice. So, that’s why he made a success in that. He’s in the telephone business, by the way. I took him up and introduced him to the General Counsel of the AT&T Company when he was looking for a job; I thought he might as well start at the top. He said, “Well, you don’t start in our company. You go down and take some rough-and-tumble law in the courts and then maybe you can come back.” But he wouldn’t give up and they finally offered him a job, and he’s been in the AT&T Company ever since. He was the youngest vice president in the whole company; He was vice president of the Chesapeake and Potomac. Then they brought him up to the AT&T Company and, he was general attorney there, and now he’s vice president of the Western Electric Company. That’s his success story. Well, now, you see, the next boy is Jim, He takes over the presidency of the University of Utah on July 1st. I hope to see him tomorrow. He’s been down there several times and we can’t get to see him. He’s getting his headaches right now, plenty of them.

Knudsen:

He’s come over here a couple of times for a headache treatment.

Fletcher:

Well, the next boy is Robert, Oh, by the way, I tried my best to get Jim to go into medicine. I said, “Now, listen, you don’t need to follow my line.” So, he went over to a school where they give these aptitude tests, and he came back and said, “Dad, I know what I’m going to, be now.” I said, “What?” “I’m going to be either a maestro leading an orchestra or a Fuller Brush salesman. That’s what they say.” And he ended up as president of a university. Now, Bob has been always a very good student. He studied probably harder than the others, and he’s got quite a brilliant mind. He’s been in the Bell Laboratories; he’s in charge of the solid state devices down there. He’s been there about 15 years now, I guess. And three weeks ago, he took charge as vice president of the Sandia Corporation in charge of research, I haven’t seen him since, I don’t know, but it’s a kind of a move for them, they’ve got seven children.

Knudsen:

And your namesake, Harvey Junior?

Fletcher:

Oh, Harvey went down to Bellcom. That’s the government working on the project going to the moon. He’s so loved it at Utah that he’s decided to come back and be chairman of the math department at BYU next year.

Knudsen:

Well, that’s a good place; we’ve come full circle. I think we have to definitely stop.

King:

Yes. I wonder if I could ask just one more question, and this is that: Dr. Knudsen has covered many, many areas and do you have any remarks that you want to make in addition to Dr. Knudsen’s remarks?

Fletcher:

No, I’m blank. Except that my other son is here in Pasadena in electro-optics, and you may want to add that.

King:

All right. Thank you, Dr. Fletcher and Dr. Knudsen.