Oral History Transcript — Dr. John Henry Dillon
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Dr. John Henry Dillon; March 21, 1979
ABSTRACT:A chat between two old friends covering the years 1932 (when Dillon became member of the Society of Rheology) to 1959 and Dillonís presidency of the Society. Eugene Bingham founder of Society, an industrial/and academic mixture; initial interest in diversity of materials; Polymers Society gets support from Chemical Foundation after 1940; the Mooney viscometer, viscosity versus plasticity (the creep curve; papers published in Journal of Applied Physics and from 1953 with separate rheology issues. Comments on international exchanges and involvement; British Rheologist Club. Also prominently mentioned is: A. Stuart Hunter.
This is an interview with John H. Dillon, who was President of the Society of Rheology in 1958-59 conducted by R. S. Marvin in Chicago at the American Physical Society meeting on March 21, 1979. Jack, you joined the Society, I think you told me at one time, in about 1932 at the Atlantic City Meeting.
Dillon: I think so. The Atlantic City meeting was my first.
Marvin: And you were a member of the Society and reasonably active from then on till after your presidency.
Marvin: And if I recall you were still fairly active for a year or two after that.
Dillon: Yes, several years after that.
Marvin: I guess you dropped out when you went to the Textile Foundation, was that it?
Dillon: Well, of course I went there in Ď46. And, incidentally, I see in my resume here, I have indicated my presidency of the Society of Rheology as Ď57 to Ď59.
Well, the election was in Ď57. Actually, I guess thatís true. Itís a two-year term. Essentially, it started late Ď57, at the end of the annual meeting. So Iíve counted them as starting with the even years to be consistent. When you first joined the Society you were working in Akron with --
Marvin: Firestone, yes, thatís right. Jim Lyons was there with you.
Dillon: Well, I hired him much later, in 1945.
Marvin: Oh, much later, OK. And at that time what were the main problems that you were interested in, that you were working on?
Dillon: Well, one of the things, being one of the first physicists at Firestone, there was a little question as to what a physicist should do at a tire and rubber company, and we had to figure out our own program for a while until we became conscious about what the real problems were. And one was that we had all this massive rheology going on, milling and mixing rubber, a good deal of it still on open mills and a fantastically interesting type of rheology of course.
Marvin: Was the term ďrheologyĒ known in Akron at that time?
Dillon: The first time I heard it was when it was suggested that I give this paper before the Society of Rheology.
Marvin: I thought perhaps not, because the founders of the Society were mostly colloid chemists, so I donít think they were --
Dillon: We did have, however, in our little library, the two or three volumes of the Journal of Rheology, so I had been able to read some of the papers, that early paper of Melvin Mooneyís, for example.
Marvin: I guess Mooney probably was the first person from the rubber industry to go into the Society wasnít he? And as a matter of fact, when you joined, what was it? Predominantly academic or predominantly industrial or was it a pretty good mix?
Yes, Mooney was the first. It was a pretty even mix, as I remember it. Of course, Eugene Bingham was the founding father you might say --
Marvin: And wasnít he also, wasnít he more than that, wasnít he really sort of the spark plug that kept things going?
Dillon: Oh yes.
Marvin: I gathered as much.
Dillon: He was a good organizer as well as a damn good scientist. But I got into it through the work which I finally decided was appropriate, and which my colleague, Norris Johnson, decided was appropriate. This was a study of the rheological properties of rubber and rubber stocks under the conditions under which they are processed, particularly in relation to rate of shear. So we went through this ordeal of trying to compute the rate of shear in various extruding machines and mills, and then trying to pick rates of extrusion for our instrument which coincided with this. We didnít, unfortunately, I suppose, pay much attention to the pure rheological flow conditions and we used a capillary which was 3/16 of an inch long and an eighth of an inch in diameter in that original instrument.
Thatís not as bad as the Ford cup, which is a tin can with a hole punched in it --
Dillon: We had a unit like that for measuring viscosity of rubber cement which was sort of laughable. This die that we set up had a conical entrance to it, and it seemed to us to constitute a compromise in relation to the dimensions of various tubing machines. Of course inner tubes are no longer made, or seldom made, but in those days that was where a good deal of our trouble came, from the extruding machines.
Marvin: I guess that was before the Mooney viscometer. That came along later, didnít it?
Dillon: I think Melvin was working on it at that time. He started off with a coaxial cylinder device before he got to the parallel plate type of thing.
There seemed to be a good deal of confusion in those days about what was viscosity and what was plasticity, and I get the impression that anytime you drew a line on your stress-rate of shear plot and had an intercept that didnít go through the origin, you called it plastic. Is that about right?
Dillon: Thatís about right.
Marvin: People didnít recognize what we now call a creep curve. Roughly, when did that really begin to be recognized? I know you were very active in that in the forties.
To start with, I got the concept from this paper of Binghamís you know, of the quite sharp intercept on the stress axis, and actually with tread compounds, high carbon-black compounds, we got behavior very close to a so-called Bingham body, and it was easy to imagine that we had it. This was, of course, with the short capillary. We went to a longer capillary later on, and that work was presented at that first Symposium at Evanston that Warren Busse organized and which led to the formation of the Division of High Polymer Physics. In this work, we finally got what we considered decent rheological data. Bob Kelsey and I did it. In this case our extrusion plastometer had one capillary about one inch long and another two inches long, so that we could study the dimensional behavior of our system with varying length of capillaries. We found that with certain types of compound under certain conditions of temperature, we got pretty nice performance in the relation between diameter and length. We were able to get very nice curves and were able to show that our old short capillary gave us something quite different. But it worked very well in the factory. And, incidentally, Bob, you might be interested to know that the factory model of that original plastometer is still being used at Firestone.
Marvin: Is that right?
Dillon: Yes, I went out there a couple of years ago, and they still use it. It, however, gives more reliable results with natural rubber compounds than it does with synthetic rubbers. I would like sometime to get into this. They had a young physicist at Firestone working in the laboratory when I was out there a couple of years ago who was very interested in studying the thing again, but apparently hadnít been given the ďgoĒ sign to spend any time on it. When we got to this better unit where we were able to vary our rate of flow with a given sample chamber load -- we had a syphon bellows, a big one, to measure the stress at a given rate -- we found we could explain very easily why they had so much trouble processing the synthetic rubbers in the plant. It was obvious from these curves. When you made a better rheological study it showed up very clearly. Milling just didnít break down GRS synthetic rubber the way it did natural rubber. I was looking at those curves the other day, and it was interesting. I was very generously treated at that meeting in Atlantic City. I was a neophyte in the game, but we did have some interesting data, and it was still made with a 3/16 inch length capillary.
Marvin: How long had you been with Firestone at that time?
Dillon: About two years.
Marvin: So you were really just getting well started. I guess at that time the Society of Rheology was pretty well diversified. Werenít there a number of people interested in metals, and petroleum, and lubrication, as well as colloids?
Dillon: Yes. And salt domes. The meetings were fascinating because of the great variety of materials they worked with.
Marvin: It seemed to go on that way, pretty much through the thirties?
Dillon: I think so.
Marvin: And then sometime in the forties certainly after WWII there was a much greater emphasis on polymers.
Marvin: Undoubtedly Herman Mark was at least partly responsible for that. Go back to the days that you first joined. I donít know how much of the details of Society operations you were aware of, maybe you werenít too deeply involved in the affairs at first. But of course, the Chemical Foundation gave some support to the Journal for those first 3 years of its existence. And then they dropped that and the Chemical Foundation supported AIP and supported the journal Physics -- the Journal of Rheology was combined with that. I donít know -- were you much aware of the details of this?
Dillon: Yes, I was aware of this. But of course I became aware of it when I was Vice President under Stuart Hunter. We were really struggling.
Yes, that was a good deal later, wasnít it? That was --
Dillon: I was still at Firestone then, I believe.
Marvin: That was much later -- I have it written down here someplace, oh yes, that was Ď40 and Ď41. For the earlier period there arenít many records of the Society because, of course, there was no medium for putting in the programs, or discussion of the programs or treasurersí reports or anything of that sort. But I take it that the Society went through a pretty difficult financial time. The Depression undoubtedly had a lot to do with it. I suppose a lot of people were without jobs and I suppose not too many new people were coming into the field.
Dillon: Travel funds were not very freely given either to industrial or academic people of course.
Marvin: And yet, interestingly enough, the membership didnít drop off too much, it seemed to keep up pretty well. They had to raise the dues to $6.00, I believe in 1933, and the membership dropped at that time. From 1933 to Ď36, it dropped from 119 to 78 but after 1936 it kept growing quite steadily.
Dillon: Iíd forgotten that.
Marvin: Can you think of any particular incident that tied into that?
Dillon: No. I will say this much. When I was serving with Stuart Hunter, he worked very, very hard trying to solve this problem. He was later head of the Quartermaster Laboratories. He was a very able man, very sincere. It really, I think, took Herman Mark to swing it, which came in after Hunter.
Marvin: Yes, Herman Mark was Ď42 to Ď46. But anyhow, the membership did go up from there. Of course, the Bulletin was started in 1937. Could it have had something to do with increasing the membership?
Dillon: I donít know.
Marvin: Or was it just those things were gradually starting to get a little better?
Dillon: I think they were starting to get a little better. There was a good deal of resistance to the word ďrheologyĒ. It had to be explained every time you were asked to go to a meeting.
Marvin: It still does to many people.
Dillon: Itís a fine name and I would never recommend changing it, but it was a barrier at one time.
Marvin: Iím sure.
Dillon: My superiors would ask, ďWhy donít you go to a chemical or a physical society meeting? Whatís Ďrheologyí?Ē Itís a very descriptive term and I have used it freely ever since and a lot of people have gotten to use it. And we certainly had some interesting people in the early membership of the Society. Nadai, for example, of Westinghouse. Very interesting guy, and, of course, Bingham was interested in everything having to do with flow. He kept pushing to get accurate measurements of viscosity in poise or centipoise, and later on got funds that went to the Bureau.
Marvin: Yes, thatís right.
Dillon: And it happened that when I visited the Bureau one time considerably later (in the late 40ís), that I ran into this chap that was actually doing this work and he was preparing these finely ground capillaries.
Marvin: Coe or Godfrey?
Dillon: Godfrey. And Theo Godfrey was Mendenhallís assistant when I came to be a second assistant at Wisconsin back in 1927, and Theo broke me in with a study of black body radiation which we did with Mendenhall.
Marvin: Well, of course that work wasnít finally completed and published until 1954.
Dillon: You know, Iíve never seen that publication.
Marvin: It dragged out for a very long time.
Dillon: Well, it was an ordeal. I could see from just spending an hour or so with him.
Marvin: Yes. A kind of a sidetrack here. I got involved in a sort of follow-up work and tried to really trace down the accuracy of the Swindells measurements. The values that Swindells put in were really precision, not accuracy. They were based entirely on reproducibility of the measurements, and as usual, the accuracy is perhaps a factor of 5 or more worse than the precision. But, anyhow, itís still the best value that people have for the viscosity of water. Thereís no question about that, but it took a long time to do. The Chemical Foundation was the one who put up the money to start that too, you know, though the Bureau financed most of it with their own funds. Well, I guess then through the 30ís the character of the Society stayed about the same, it was pretty broad, diversified subject matter.
Dillon: With a good deal of it experimental.
Marvin: And then Mark had a good deal to do with bringing in a number of theorists like Eyring, and brought in a good many University people. He also attracted some industrial people, though I suppose his students at Brooklyn, and people of that sort. When I talked to Dow, who was secretary at that time, he said that he thought the Society had sort of drifted down after Bingham had to give up his activities. Bingham got pretty ill you know in the late 30ís, and he had to resign as Editor. While he was still on the program committee, I take it; it was more or less honorary.
Dillon: I think probably thatís true.
Marvin: Iím sure he wasnít as active as he had been, and Dowís statement was that Mark was really the one who stimulated the Society and got it going again. Does this jibe with your recollection?
Dillon: Thereís no question about it. I think though, that probably Hunter, through just plain hard work, laid a foundation for which he is not given enough credit.
Marvin: Perhaps so. It may be that Dow was not as familiar with Hunterís work.
Probably not. The thing came to fruition under Markís guidance -- thereís no question about that. But I think Hunter played a role that is little understood.
Marvin: Well, of course Mark was probably a good deal better known than any of the Presidents that preceded him. He already had quite a name for himself before he came to this country.
Dillon: Oh, sure. Yes. Let me see. Wheeler P. Davey, when was he President?
Well, let me see. He was the first President. He served for two terms Ď30-'33. Then it was Sheppard, then Melvin Mooney for two terms, then Stuart Hunter, then Herman Mark, for two terms. Then Fair for two terms. Then Traxler, Spencer, Markwood, Dexter and yourself, then John Elliot after you. I guess there never was really any pattern of the two-term presidency. At one time, when I first joined the Society, I had the impression that this had been the practice, but in looking through the records, I see that itís jumped around quite a bit.
Dillon: You know, I donít recall, did I serve two years?
Marvin: No. Yes, two years, not two terms. Well, letís see. There was a lot of stuff in the Journal of Rheology, and later in the Bulletin about definitions and nomenclature, and so on. Did you get involved in that?
Yes, I got involved in that. I donít remember just who was working with me on it, but I think it was when I was second Vice-President or something like that. I remember where I did it, it was in an apartment that I occupied soon after I was married, and my facilities werenít very good and my knowledge of the field was nowhere near as deep then as some of the other members, but I was, of course, interested in it and trying to work out a set of consistent definitions and nomenclature, and yet I didnít go deeply enough into it. I could tell very soon after that, because Herb Leaderman was involved in the thing later on.
Marvin: Quite a bit later, I think.
Dillon: Yes, and there was very little resemblance between what I turned out and the final product. It was good practice for me, but I donít think I advanced the cause very much.
Marvin: Donít you suppose that was because when you were trying to do it then, we had a pretty incomplete understanding of what the phenomena were?
Dillon: Very much less complete understanding than we had later on.
Marvin: Of course the reason Leaderman was able to come up with a good set of definitions was that he limited himself strictly to linear viscoelastic behavior on which by that time we had a good background, so we could do it. Back in the 30ís I guess they were still trying to struggle with what viscosity was, and what flow was and so on. Itís much like trying to make up definitions and nomenclature in the nonlinear field today which is still a big mess.
Dillon: Yes, I imagine so.
Marvin: That, as a matter of fact seemed to attract a great deal of attention from Bingham; he seemed to be extremely interested in that. He was writing articles about it all the time. Bingham also seemed to be very ambitious in keeping up these abstracts of his and his listing of rheological papers. I noticed, when the Bulletin started coming out, he had page after page of those things. Did you find those particularly useful?
Dillon: Yes, I did.
Marvin: Was this something that was really helpful?
Dillon: Very helpful.
Marvin: And I noticed that the Bulletin for a great many years carried abstracts. This was dropped about 1946. Certainly part of this was financial. Was that the only reason?
Dillon: No, a coupling of that with the fact that the field was growing at a tremendous rate and that the labor of keeping up and producing a fairly complete set of abstracts was just beyond the human capabilities of the people who were trying to do it for the Society.
Marvin: I see, it wasnít that we thought they were being covered adequately by Chemical Abstracts or anything of that sort?
Well, I think there were some thoughts that Physics Abstracts and Chemical Abstracts were big high-powered operations. But they were not of course channeled into pure rheology. Of course, it is always too bad when a program like that slumps, but it just got to be a terrible, terrible job and I guess we just decided that we were going to have to put up with other abstracts.
Were you involved at all in the switch-over of our publications mechanisms when we started publishing in Journal of Colloid Science for instance? And before that in Journal of Applied Physics? You remember back in Ď33-'36, four issues of Physics, that was a predecessor of Journal of Applied Physics, were designated Rheology issues. Then they changed the name to Journal of Applied Physics, and some papers from the Society meetings were still published there, but the issues were not identified. As a matter of fact, they didnít come out as any specific issues and I have discovered no pattern to the way they were published. Do you recall anything about this?
Dillon: I remember that we had a very nice set up with Physics. And actually, I remember publishing in Physics some of my early papers, and when we got to the Journal of Applied Physics, we all liked the Journal very much, but I donít remember why the same system didnít convert over, having specific issues allocated for rheology.
Marvin: I donít know --
Dillon: I donít know either.
But between 1937-46 in the Journal of Applied Physics, there were no separate rheology issues, and I havenít found any easy way of identifying where the papers from the rheology meetings came out. Some of them did; you can go through the contents and authors index and pick out names that you associate with the Society, and sure enough sometimes they will be footnoted as presented at a Society meeting.
Dillon: Now you see this paper that Kelsey and I gave before the Division of High Polymer Physics was the purest rheology paper that I had ever sponsored from Firestone. But here the Division was being formed and I was active in forming it and we were trying to put on a good showcase program at Evanston, and before we knew it we had three papers there and that was one of them.
Marvin: When was that?
Dillon: That was in 1943. Iíve got the issue of the Bulletin with me, but itís in my other file upstairs.
Marvin: Well, of course there was a period a little later; I donít know when it started, when it seemed to me that it was pretty hard to distinguish between the Society of Rheology and the Division of High Polymer Physics. The meetings were almost interchangeable, the programs I mean.
Dillon: Thatís right.
I donít know when did that start? Was it--
Dillon: Well, it began as soon as the Division was formed. After all, this work of Tobolskyís on stress relaxation, chemo rheology, as he called it later on. Mostly, it was published in other journals. It was published under the auspices of the Division of High Polymer Physics, because he gave that first paper of his as a graduate student when he was a Firestone fellow at Princeton. He gave that in Ď43 at Evanston. And later on his papers were published in every conceivable journal and form after that. But thereís no question that the Division of High Polymer Physics just naturally siphoned off part of what would have normally been considered rheology, and I donít think it did any particular harm. Sometimes I think itís nice just to put all things in one basket but itís pretty hard to keep it that way.
Marvin: Well, of course both groups have changed over the years. High Polymer Physics became all crystalline polymers there for a while. Rheology switched a different way. Itís an interesting growth there. It started out, I guess you could say (that is Rheology) as pretty much a phenomenological science, and then in the period of the 40ís and early 50ís it was almost indistinguishable from Polymer Physics and went into structural matters quite a lot. And then it swung back again to a certain extent when people went into the nonlinear range of getting more phenomenological and of course a great deal more mathematical. Is that a fair summary?
Dillon: I think so, very good.
Marvin: So you canít recall just what the reason was for not getting better treatmentí in the Journal of Applied Physics during that Ď37 to Ď46 period.
Dillon: No, I donít think that any of us were conscious of being treated badly at the time. Our papers got published there, and I wasnít conscious of you mention it right now. Now that you mention it, I remember that papers were not grouped the way they had been in Physics.
Marvin: Well, it must have made a -- it didnít give you the advertising that you get from an identifiable journal, and I should think that this made it more difficult to attract members and so on.
Dillon: It could have.
Well, anyhow, from Ď47 to Ď52 we published in the Journal of Colloid Science and then back again to the Journal of Applied Physics from Ď53-í56. But this time in identified issues, identified as rheology symposia on the cover. And then starting in 1957, of course then we went to the Transactions.
Dillon: Letís see, Rod Andrews was the editor there for quite some time.
Marvin: Not very long --
I think he was the editor when I was President. Iíd say Ď57-í59, Iím sure Rod was responsible for that.
Marvin: Yes, Rod Andrews was the editor when you were President, but just the one term. Letís see, were you at the third meeting by any chance or was that before your time?
Dillon: Which one was it?
Marvin: 29, 30, 31. No, I guess not.
Dillon: No, I got my degree in Ď31.
Marvin: That apparently had an unusually big representation from Europe. The Society in Binghamís view was an International Society -- it certainly started out that way. The board of editors had a lot of European Assistant editors and at this third meeting I believe it was, there were a raft of papers there, there were up to 13 papers at one evening session. But the things were all preprinted and just discussed very briefly. The Society always seemed to go in for evening sessions, didnít it.
Dillon: Yes, and this idea of the ďsmokerĒ was Eugene Binghamís idea, to sit there informally, and that became the occasion to give the Bingham medal. And I distinctly remember giving Melvin Mooney the Bingham medal which he somehow lost.
Marvin: Oh for heaven sakes.
Dillon: And he let on later on that somehow he and the medal parted company at that meeting when it was given to him. Some people kidded me, asking if I really turned the medal over or not. And so we had another medal cast for him.
Marvin: Good. In later years it turned into a dinner rather than a smoker, but there were evening technical sessions at a lot of the meetings.
Dillon: I guess there were, that was probably after my active period.
Marvin: I thought that these were at some of the early meetings also.
Marvin: During the thirties, during the Depression there wasnít too much activity in the way of European people coming over?
Dillon: I donít recall that there was.
Marvin: They must have always had some European members. Mark said he joined when he was in Vienna in about Ď32.
Dillon: Scott Blair from England.
Marvin: Scott Blair. He was an active member for quite a few years.
Dillon: Right off hand, I canít think of others at that time. We used to sort of exchange programs sometimes with the Society of Rheology in England.
Marvin: British Rheologists Club. But that was later, that was after WWII. They were formed during WWII. This shift from Journal of Applied Physics to Journal of Colloid Science. I noticed here I had a note to ask you why that shift was made. Apparently you just donít remember.
Dillon: I just donít remember at all.
Marvin: You donít remember if they were limiting us in the number of pages or anything of that sort? I know later on they did after the second shift from Journal of Applied Physics.
Dillon: I just donít recall.
Marvin: Well, I guess really that just about covers the major points I wanted to ask you, Jack, and I know you want to get down -- Iím sure a lot of people will be waiting to catch you down at the cocktail hour and the banquet. So let me thank you very much for taking time for this interview during a busy meeting.