Louis Hammett - Session II
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ORAL HISTORIES
Interviewed by
Leon Gortler
Interview date
Location
Medford, New Jersey
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Interview of Louis Hammett by Leon Gortler on 1978 May 22,
Niels Bohr Library & Archives, American Institute of Physics,
College Park, MD USA,
www.aip.org/history-programs/niels-bohr-library/oral-histories/4654-2
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Abstract
Childhood and major influences; college education at Harvard University; position at Edward C. Worden Co., position at Columbia University's chemistry department as a graduate student and instructor, as a professor, and as the department chairman; history of chemistry department's administration. Major emphasis on his research results and papers spanning his entire career; Hammett equation and acidity theory; his contact with students Henry P. Treffers, Martin Paul, Lois Zucker. Work during the World War I and World War II; consulting work; development of the field of physical organic chemistry and opinion of the future of chemistry. Philosophy of research; talk with Mrs. Hammett. Also prominently mentioned are: Roger Adams, Adkins, Bernard Auchincloss, Paul Doughty Bartlett, Hal Beans, Ernst Bodenstein, Marston Bogert, Branch, Breslow, Johannes Brn︣sted, Joseph Bunnett, Burkhardt, Mary Caldwell, Ray Christ, James Bryant Conant, Ralph Connor, Alder J. Deyrup, John R. Dunning, Henry Eyring, Leo Flexser, George S. Forbes, Ernie Grunwald, Janet Hammett, Arthur R. Hantzsch, Christopher Ingold, Iserman, James Kendall, Elmer Kohler, A. B. Lamb, Irving Langmuir, Jose Levy, Gilbert Newton Lewis, Willard Frank Libby, Bill McEwan, J. L. R. Morgan, Rosetta Natoli, J. M. Nelson, James Flack Norris, Louis Plack, Michael Polanyi, T. W. Richards, R. Robinson, Smith, Alexander Smith, E. F. Smith, Hermann Staudinger, Julius Stieglitz, Arthur Thomas, Harold Clayton Urey, George Walden, Chaim Weizmann, E. C. Worden, Theodore Zucker, Dick Zuemer; Alpha Chi Sigma Fraternity, American Chemical Society, Commercial Solvents Co., E. I. duPont de Nemours & Company, Inc., Eidgenössische Technische Hochschule at Zurich, Johns Hopkins University, Manhattan Project, Petroleum Research Fund, Rohm and Haas Co., United States President's Science Advisory Committee, Universal Oil Production Corporation, University of California at Los Angeles, University of Illinois, and University of Wisconsin.
Transcript
Hammett:
By the way, I have here a memorial minute which I prepared and presented to the faculty of pure science on Hal Beans, who was my research director.[1]
Gortler:
That will be great. I would like to read it. I guess the first thing we should clear up is the identity of the Harvard faculty member we had difficulty remembering last time.
Hammett:
Yes. Grinnell Jones. I knew him very well. I won’t say I knew him intimately but he was technically my advisor as an undergraduate.
Gortler:
Oh, yes. I wanted to mention that I looked for a depository for the papers you gave me last time. I suspect I will end up taking them to Columbia and asking them to put them in their archives.[2]
Hammett:
This was the material I used in working on that second edition.
Gortler:
Yes. I sort of glanced through some of the work and I was impressed by the meticulous way that you did so many tables by hand. There were some letters I found amusing and interesting. Last time I asked about whom you discussed your ideas about acidity with and the answer that came up very readily was Deyrup. That came off the top of your head. You must have thought quite a bit of Deyrup. I wanted to ask you about what happened to him.
Hammett:
I admired him a great deal. Well, he had two years as a National Research Council Fellow. I’ve forgotten the exact title of the fellowship, but it was National Research money, Federal money. And he spent them at Wisconsin working on a project of his own. I’ve forgotten now what it was. It was quite different from the acidity work. But he wasn’t able to get a teaching job, a university job. Of course, this period was a tough time for young people trying to get university jobs. He was, however, a very bright fellow. He finally got a job with a DuPont outfit at Buffalo or Niagara Falls and was working on what they called glass enamels. These are materials that are put on glass for advertising purposes and then they are fired into the glass. They have to have all kinds of special properties, for instance, a moderate melting point below that of the glass, and the right coefficient of expansion, and they have to have the color and all that. Apparently he had quite a good time working on them, but he never got into any pure science work and finally retired. I’m not sure whether he’s still alive.
Gortler:
I noticed in one of the papers that he was a Gottsberger fellow. Was that some kind of support the department had?
Hammett:
He must have made it on his own. I didn’t have any fellowship money. The idea of using the overlapping indicators was definitely mine. The name acidity function, however, was Deyrup’s. I mean we collaborated. He did all the hard work of testing the indicators; we had to check all their freezing points in strong sulfuric acid to see whether they were simple basic indicators. And as it turned out, almost all the indicators we used were nitro anilines. This was a fortunate feature, because we later found out that this wasn’t a unique acidity function; you could get other acidity functions depending on other kinds of weak bases. We didn’t suspect that at the time. All we were able to work with was the visual spectrum. As we found out later this was, to some extent, a lucky break because when we got to working on the ultraviolet spectra later on, we discovered that what we were working with, in this case, was the tail end of an absorption curve that peaked out in the ultraviolet and just overlapped a little into the visible. The only absorption of a yellow substance was in the far violet. The difference between a colored and a colorless material depended upon right or left shifts of the whole absorption curve. I learned from Selig Hecht that the human eye is very insensitive to changes in color quality in the yellow. These were all yellow colors and the curve shifted laterally. The tail end curve went up or down because of the shift but you didn’t appreciate it as a change in color quality; consequently you didn’t have any trouble matching the colors. And that was a lucky break too. Later on we had to worry about this when we were working with the ultraviolet and we were observing the intensity of the peak absorption. We were worried about these changes in intensity of peaks coming out as changes in color in the far violet.
Gortler:
You did the concentration by just comparing the intensity of the color?
Hammett:
That’s right.
Gortler:
That must have been very tedious work.
Hammett:
Well, it was, yes. Deyrup was a very hard worker and he did an awful lot of work.
Gortler:
You did mention the job situation. This was the early 1930’s. What was the general job situation? Were you concerned about your own job and about jobs for your students?
Hammett:
Well, I was concerned about jobs for my students. As I said, here was Deyrup who had this outstanding record both with me and at Wisconsin and he just couldn’t get a university job. He tried, he certainly did. And I backed him hard and promoted him, but he had to take this relatively unattractive industrial position.
Gortler:
Do you think the social and political climate during those beginning years, well, from about 1925, affected your work in any way?
Hammett:
I don’t think so. One thing, I think we might as well say it, the chemical industry and to a considerable extent, the universities, were prejudiced. Deyrup wasn’t Jewish, his antecedents were Scandinavian, but I had a good many Jewish students and it was especially tough for a Jewish student to get a job in that period. During the Second World War, when I was in charge of a laboratory, a government laboratory, I had a good many Jewish chemists on the staff and they insisted that they ought to be given a head start in searching for jobs. The end of the war was approaching and the government sort of put a freeze on people working in government research laboratories and some of the Jewish staff was very anxious to get out ahead because they knew of this prejudice. The funny thing is that when the war ended the prejudice disappeared, just completely. Before the war DuPont wouldn’t hire a Jewish chemist and after the war their representatives went around begging for them. Of course I had a good many graduate students who were Jewish, and I have absolutely no anti-Semitic prejudices, and I resented the state of the climate. I found it very unfortunate. I’m sure it hurt Columbia University. The University was attacked by Rabbi Weiss for not taking in enough Jewish students. I was on the special committee on admissions, and I’m sure that the Director of Admissions, whom I knew well, was simply following the principle that the university wished to be a national university and they wouldn’t allow themselves to be overwhelmed by students from New York City. Most of the bright students from New York City were Jewish. Actually, the university had a policy of taking in about a third of the entering class in the college from New York City and another third from the suburban area and the final third from outlying parts of the country or foreigners. For instance, we had a lot of students from Little Rock, Arkansas. This was just sort of a tradition out there; one or two students would come to Columbia and do well and the word would get back. I had a number of graduate students later on from Monmouth College in Illinois, and this was, again, word of mouth. One man had started working with me and he passed the word back that Hammett was a good man to work with.
Gortler:
Since you brought it up, several weeks back a colleague of mine who was a graduate student at Columbia back in the late ‘40’s and early ‘50’s, mentioned the case of Grunewald. He said that at some point Grunewald was at Columbia and there was some thought of keeping him on the faculty and that… there was some to-do at that time and he thought that it may have smacked of anti-Semitism. Do you remember anything of that?
Hammett:
I don’t think so. Grunewald (now at Brandeis) came to Columbia on a fellowship and worked on his own problem in my laboratory. I don’t remember any thought of appointing him at Columbia, and I am sure there was no element of anti-Semitism. We hired two or three Jewish people in that immediate post-war period. In fact, the present dean of the graduate school, George Fraenkel, was one of them.
Gortler:
In general, did you find graduate students easy to come by?
Hammett:
I think one of the things that was favorable to me was an advanced course in qualitative analysis that I taught, because I inspired a group of undergraduates and when they became graduate students, quite a few of them wanted to work with me. And then I did teach a course on valence theory. It was a general course on valence and it had a lot of Werner theory about cobalt amines, and the Lewis’ ideas and I think Pauling’s resonance idea and X-ray crystal structure. It was a rather broad course, and I had a lot of fun with it. I read rather widely and it probably educated me as much as it did the students. I’m sure that brought me some students.
Gortler:
How did you go about selecting your graduate students?
Hammett:
At that time we had a rather rigid scheme of trying out new graduate students. They had to take courses from a specified list and they had to pass a general examination before they were eligible. If they went through that, I didn’t want any selection, I was happy to get them.
Gortler:
Did you look for particular characteristics?
Hammett:
No.
Gortler:
Could you predict in advance somebody who was going to be particularly good or creative?
Hammett:
No. They had been through a selection process independent of me and they had the good taste to want to work with me.
Gortler:
Obviously the early ones worked pretty hard as Deyrup did, how about the others?
Hammett:
Mostly very good, yes. I have no complaint about them.
Gortler:
Did you notice that as the years went by if there was any change in the habits of the students?
Hammett:
No. They were a very good lot, almost all of them. Willing to work very hard and sometimes do very tedious work. For instance, all of the ultraviolet absorption work was terribly dull.
Gortler:
Yes, I wanted to ask you about that again. You described that to me last time and I still didn’t get the whole picture of it.
Hammett:
This was the ultraviolet spectrophotometer and it involved a photographic stunt. You had a many-line spectrum, an iron arc or something like that. Then you had a split beam and one of the beams went through the absorption cell containing the material you were studying and the other went through a rotating sector photo photometer and then you got a picture of the whole spectrum; actually, two of them, side by side. Then you would find a place where the two spectra matched in intensity and that told you that at that wave length the absorption was given by the factor of your sector. You had to match these things visually from the photographic plate. You’d have a whole set of plates with different sector settings and each sector setting would give you a point on the absorption spectrum. If you made enough of them you plotted the whole spectrum. This was hard eye straining work. What you can do now with any one of these modern ultraviolet or visible spectrophotometers in five minutes would take us weeks of hard work.
Gortler:
Were there other physical organic chemists around at the time?
Hammett:
None around.
Gortler:
Were your students graduating as physical chemists or physical organic chemists?
Hammett:
Neither. They graduated as chemists. We didn’t label them. One of my bright students, just before the war, was being interviewed by a prominent chemical firm and the interviewer asked him what kind of a chemist he was. He said he was a physical organic chemist and the interviewer said “What’s that? We know what organic chemists are, they make new compound, we know what physical chemists are, they measure the numerical values of quantities of things that are important for our industrial technology, but I don’t know what a physical organic chemist is.”
Gortler:
So industry really wasn’t accepting physical organic chemists.
Hammett:
Industry was certainly not looking for them, no. By contrast, after the war they were hunting for them and by name. But during the ‘30’s, even the late ‘30’s, they weren’t.
Gortler:
How about the academic world, were they really looking for them?
Hammett:
I don’t think so. There were a few such people in the academic world. There was Bartlett at Harvard, for instance, and, of course, Conant had been there. And I’m trying to think who else there was. There weren’t an awful lot of people who were actively involved in that field.
Gortler:
One of my thoughts was that there might have been some resentment among physical chemists in accepting someone who called himself a physical organic chemist, and there might have been some resentment among organic chemists in having a physical chemist come in, in sheep’s clothing, you might say.
Hammett:
All I can say as far as the organic chemists went; they fell for physical organic chemistry hard. I remember Roger Adams at a National Academy meeting. They used to caucus the physical chemists and the organic chemists separately, and I hung out with the physical chemists. Once Adams beckoned to me and said, “Come on over here, this is where you belong.” He was an old line organic chemist but he certainly was pleased to have me with them. I’ve had many organic chemists tell me that my book just revolutionized their whole work, I mean; they began to think seriously about the problems related to this sort of thing.
Gortler:
I don’t think there’s any question about it. It’s a true statement.
Hammett:
They welcomed it. They welcomed the quantitative approach.
Gortler:
That really is the theory of organic chemistry and that’s where and when it developed. Before that time there was almost no theory.
Hammett:
That’s right. As I told you before, the kind of organic chemistry I studied in Zurich didn’t even mention the importance of reaction rate measurements.
Gortler:
Earlier I had asked you to check off a few of your papers and I’ve looked at the paper with Pfluger.[3] I thought it was an incredibly futuristic paper. Would you tell me something about your thoughts in developing some of the ideas at that time?
Hammett:
Well, of course, an important factor in my thinking was the Bronsted reaction rate-equilibrium idea, and the idea of plotting the logarithm of the rate against the logarithm of the equilibrium constant. That originated with Bronsted, there’s no doubt about that. The idea that you could get a linear relationship in that kind of a plot came from Bronsted. Well, then somehow or other, it popped into my mind that this kind of relationship suggested a solution to a currently interesting problem, namely the mechanism of ester hydrolysis. It seemed to me reasonable to suppose that if it were an ether type break, you see, it would behave one way with respect to the change in structure of the acid radical. If it were an acyl-oxygen break, it would behave a different way. Therefore, it would be sensible to compare the rates of reaction of esters with a particular alkyl group to the rates of hydrolysis of the same esters. With the Bronsted log relationship in mind, it just seemed reasonable to try plotting the log of the rates. Well, that was a bright idea as it turned out. I claimed that that was the pioneer example of a linear free energy relationship between different reactions; closely related, but different reactions.
Gortler:
In the same paper you started to discuss the ideas of what we now call SN1and SN2 reactions. I guess that nomenclature wasn’t in use yet.
Hammett:
No. That was Ingold’s nomenclature.
Gortler:
Now this was the real beginnings of linear free energy relationships. One of the things I noticed was that one of the reactions that later became a real classical example, you plotted in that early paper. It was the rate of alkaline hydrolysis of esters versus the acidity of the acids and you didn’t get a straight line. I guess what happened at that time was that you picked the wrong acids. You threw in the acetates.
Hammett:
You get a straight line if you restrict yourself to nuclear substituted aromatics. But the aliphatics and the ortho substituted aromatics don’t lie on that line.
Gortler:
And even then you suggested it might be a steric problem.
Hammett:
Yes.
Gortler:
That being the beginning, what happened after that? How did the idea begin to grow?
Hammett:
Well, the next thing was that both Burkhardt at Manchester and I noticed that you could get linear relations between aromatic derivatives of rather unrelated types of structure. And I think we were both plotting them linearly. It was rather obvious when we began to look at it that the relation was limited to systems in which the change in structure was fairly far off from the reaction zone. I recognized more than Burkhardt did the generality of this and I thought of a rather simple idea of relating all reactions to just one key reaction which, of course, leads to the so-called Hammett equation.
Gortler:
Why did you choose the acidity of the benzoic acid?
Hammett:
Because there were a lot of data available. Just on that basis.
Gortler:
Now were you communicating with Burkhardt or with anyone else at this time?
Hammett:
No.
Gortler:
Then the ideas were pretty much your own?
Hammett:
That’s right. I don’t think Burkhardt ever followed it up very much, Of course, Ingold refers to this as the Burkhardt-Hammett equation, or Hammett-Burkhardt, I forget which. I’ve met Burkhardt. He’s a nice chap. I met him when I went over to the Faraday Society Meeting. He noticed the fact that you could compare two different reactions of Meta and Para-substituted aromatic compounds, but he didn’t generalize it, and I don’t think he ever followed up. I don’t know what his field really was.
Gortler:
You published one review article in thirty-five[4] and then by thirty-seven,[5] I think, the so-called Hammett equation was published. At that time you had something close to forty correlations.
Hammett:
Yes. The 1935 article reported relationships between the rates of a series of reactions and the equilibrium constant of the same or of a closely related series. The Hammett equation idea appeared first in the 1937 papers. The 1937 publication was in the JACS. I essentially repeated the same material in an article for the Faraday Society.[6] I had a hand operated calculator and did all those linear free energy plots by brute force. I did them myself. I didn’t have any help on that.
Gortler:
Leo Flexser? He did the work with the ultraviolet absorption.
Hammett:
Yes. He’s vice president of Hoffmann LaRoche and he’s done very well. But again, being Jewish, he had a devil of a time getting a job; a rather difficult case.
Gortler:
He was listed as a university fellow in chemistry. What did that mean?
Hammett:
There were a small number of graduate fellowships under the control of the graduate dean. I was lucky enough to get that for him. He and I together pulled it. He was one of the boys whom I first met as an undergraduate and who followed it up and went into graduate research with me.
Gortler:
Did many of your Columbia students stay on? Did you get a number of graduate students that way?
Hammett:
Of course, to begin with we had very few undergraduates who concentrated in chemistry. The university wasn’t oriented toward pure science at all. If a youngster wasn’t literature oriented or economics oriented, he was pushed toward the engineering school. You see, they had an undergraduate engineering school and the advisers to freshmen tended to be from the engineering side, so we had a hard time getting good undergraduate students in chemistry. But we did have some very good ones. If you take that list of people I sent. Do you have the list of publications?[7]
Gortler:
Yes, and the list of people.
Hammett:
Now, Arthur Lorch was a Columbia student; Helmuth Pfluger was a Columbia student; Fred Lowenheim, Leo Flexser, Irving Roberts, Henry ‘Pete’ Treffers. I had some money you know, from Auchincloss[8] and I hired Treffers as a laboratory assistant while he was still an undergraduate. Then he went on and did graduate work with me.
Gortler:
While we’re talking about Treffers, could you tell me what happened to him?
Hammett:
He’s head of the microbiology department at Yale. He did a nice job, a good piece of work, but he got very interested in the biological side and he took a post graduate job at the medical school with Michael Heidelberger. He had a group and was trying to build it up and he wanted a physical chemist so he hired Pete as a physical chemist and then Pete built himself into a microbiologist. As I say, he ended up as head of the microbiology department at Yale, which is a long way from freezing points in concentrated sulfuric acid. Now, I also had some students who came from City College. Sylvan Edmonds and Martin Paul. Martin Paul was what they called a tutor, I think, at City College and Edmonds was, too. And then, I guess, the first of the people from Monmouth was Ray Betts, and he was followed by George Beste, Harold McCleary, and Glennard Lucas. Fraser Price was a Columbia undergraduate and so was Gettler.
Gortler:
The paper with Joseph Steigman[9] was a bit of a surprise for me. I didn’t realize you had done quite so much work in nucleophile substitution. That was really some very basic work.
Hammett:
We almost beat Ingold on the inversion as the major form of the SNI reaction. Ingold beat us by a few months.
Gortler:
That’s an interesting aspect. I was very curious about the fact that you, in that particular paper, didn’t concede that the solvolytic reaction was really simple. In one line you said it could proceed through free carbonium ion, but then you said you thought it was a poly-molecular reaction.
Hammett:
Well, I had several people working in that or related fields at about that time. Joe Steigman and Nicholas Farinacci. I think the poly-molecular term grew up out of discussions that we were all involved in. I’m not even sure who originated it, that is, the idea that there might be several solvent molecules involved. The other thing that, I think, had an effect on my thinking was the work showing that the accelerating effect of water on an alcoholysis reaction was not due to the direct involvement of water in the reaction.
Gortler:
Looking back, it seems so forward looking. It was futuristic, and, again, you were really right. When I was going through the list of your papers I noticed one of the concepts I’ve always had some difficulty with. Maybe that’s why you didn’t suggest we discuss those papers. The papers concerned the plotting of H0 vs. rate and what that really means in terms of mechanism. I don’t even know exactly what to ask you. There’s been so much discussion and literature about the idea. In your 1970 book, you, as far as I know, totally ignored some ideas suggested by Bunnett in 1960 that tried to rework that whole idea, and I wondered if that was intentional on your part or what?
Hammett:
I’m afraid it was intentional. Although I accepted Bunnett’s modified equation. I think it’s a very good one, but I didn’t accept the speculations about mechanism.
Gortler:
I see. Do you have, in retrospect, any ideas about whether one can really make any clear cut statements about mechanism when you do or do not find certain slopes [correlations] with respect to H0?
Hammett:
It always seemed to me that these different H0 rate relationships represented differences in the degree or intensity of solvation of the base or its conjugate acid. I think that may be Bunnett’s idea, too. I don’t remember exactly. The realization that there’s more than one H0 rate depending upon the type of base involved didn’t really enter my mind until after the war. A factor in that was the discovery by Hinman at the Carbide research laboratory that there was a different relationship for a certain kind of base than there was for the nitro aniline bases that we originally studied. And then Frank Long, also, at Cornell, had discovered another group of bases that followed a different line. I was rather slow to accept that; the fact that there was more than one kind of a base and that you had to take bases that were related in structure to get a single unique relationship. That was an idea that I appreciated only after the war. As a matter of fact, it was only after I retired, along in the ‘60’s, that I got that far.
Gortler:
There were two people who were really very much into that research with you. One was Martin Paul, whom you seemed to be very close to. You did tell me a little bit about him privately and I wondered if you’d repeat that. His career was an interesting one.
Hammett:
Well, I was research director of a government laboratory at Bruceton near Pittsburgh and Martin Paul was continuing at that time as a tutor, I think they called them tutors, at City College. But I was able to interest him in coming out to Bruceton to the laboratory of which I was research director. He did very good work there, although not directly in my group. We knew him and his wife, and we were in and out of each other’s houses and thought very well of each other. His wife comes from an old Long Island family; from far out Long Island. She was a very nice woman and they had a couple of nice children. We were friendly. The war ended and Martin accepted a job at one of the Navy installations. Then he was accused of being a left-winger and fired. A lot of us went to bat for him. I was convinced that he was a thoroughly decent patriotic American, but apparently there were some things in his background as a student at City College that bothered the red baiters. I know Jim Conant wrote a letter in support of him, and Ralph Conner and a lot of people who were heavily involved in war time research backed him, but it didn’t do any good. They wouldn’t take him back. He managed to get a job at Harpur College in Binghamton, and did very well there. Although it was purely an undergraduate institution he managed to get some research done and do some thinking. In fact he wrote a paper with Frank Long...[10]
Gortler:
Yes, almost a classic.
Hammett:
Martin went back and forth, it wasn’t very far from Binghamton to Ithaca and Martin was in and out up there. I had him down as a summer session instructor at Columbia once or twice. When he was getting pretty close to the retirement age at Binghamton, the chairmanship of the division of chemistry and chemical technology at the National Research Council became vacant and Frank Long, who was very active in National Council affairs, was largely responsible for getting Martin the job as chairman of that division. He held it for a good many years. He’s now retired; a very nice fellow.
Gortler:
And the other student who did quite a bit of work in that area was Lois Zucker.
Hammett:
Yes. Lois Zucker was a Barnard student, who concentrated in chemistry. Apparently she got a job as a research assistant with Professor Zucker at the medical school; Theodore Zucker. Zucker was the fellow who discovered that you could spike milk with vitamin D. The university, I think, took out the patent or he assigned it to the university in return for support for his research. Well, she married Zucker. Her maiden name was Mason, Lois Mason. She married Zucker and he was a very devoted husband and encouraged her to go on in chemistry. He looked over the kind of work that was being done in the graduate school at Columbia and he sponsored her working with me. She was a very industrious, hard-working person.
Gortler:
Yes, you have several papers with her.
Hammett:
In fact it was hard to stop her. Her work involved not only very careful reaction rate work which had an important mechanistic result, but attempts to relate the rate of reaction with different substances to the base strength and that sort of thing.
Gortler:
Some of her work that we talked about before the implications with respect to mechanism were very often referred to as the Hammett-Zucker hypothesis.
Hammett:
That was a mistake. It was a failure to realize that this wasn’t a mechanistic difference, it was a difference in the type of base involved and we didn’t know it. It was, let’s say, a stab in the dark. We recognized that these rates were more closely related to what you’d expect from one mechanism instead of another one.
Gortler:
The next paper that you checked off was the Price[11] paper on temperature coefficients of the rate formation of semi-carbazones and again I think the title was deceiving. One didn’t realize what the impact of that kind of research would be until you really got into the paper.
Hammett:
I admit that wasn’t a very illuminating title. I think we might talk about titles. I have had the feeling that it’s very important in titling a paper to put into the title everything you’d like to have the subject matter indexed under. That was a rather long title, you see, with a colon in it. As you say, the important thing about the research was a failure of the entropy to parallel the actual free energy of reaction.
Gortler:
Right. Usually for related reactions, entropy does not change or else the changes parallel the enthalpy.
Hammett:
In this case it wasn’t related. It was completely unrelated. Gettler later developed this idea further. He studied other related reactions, the thiosemicarbazone formation was one example, and found the same sort of randomness in the entropies, which I thought was an important fact.
Gortler:
I think that in at least the later book, and perhaps in the earlier book, you spent a good deal of time discussing the interrelationship of enthalpy and entropy. The Price paper was also the last important paper before the war. That came out in ‘41 I believe. You were obviously not oblivious to the war signals.
Hammett:
No, I was not. Lucas’ work,[12] you see, was another effort to use the effect of structure on reactivity to determine, or to get clues to, reaction mechanism. We were studying various reactions of alkyl nitrates. The work of Lucas and Gettler and Smith, the Smith paper wasn’t published till ‘45, but that was all pre-war work down to publication #57.[13] Smith came out to Bruceton with us. I had a student, Rosetta Natoli, who was working in the same field as Smith after the war, and there was some disagreement between the temperature effects she found and what Smith had found. Of course, this was published as a Ph.D. thesis, as all Columbia theses are, and we had it listed in the microfilm scheme, but we never published it in any of current literature. About that time Van Looy came along and I put him to work on the same field and he cleared up some of it. It was a very nice piece of work. I think we did a good job on that. You haven’t said anything about our work in concentrated sulfuric acid. There were several papers involved in that. I guess I may not have checked them [for discussion] but they were quite important, I think. Pete Treffers did cryoscopic studies on bases in sulfuric acid. That was good work, because it showed that di-ortho substituted benzoic acids behaved differently from other aromatic acids.[14] This was published in ‘37. Of course Deyrup did some work in concentrated sulfuric acid and Lowenheim did, too. We were puzzled by Kantzsch’s results on freezing points of aromatic acids in strong sulfuric acid. And so I put Lowenheim to work studying the transference numbers and it turned out that the solvated hydrogen ion is of terrifically high mobility. There had been speculation that that might be the case, but this was the first real evidence that in concentrated sulfuric acid you had this tremendously high mobility of the solvated hydrogen ion.
Gortler:
I would like to talk a little about your war work. You started to work, at least peripherally, with Conant as early as 1940. He had taken a position in the government.
Hammett:
Yes. I’d been corresponding with Conant. I never worked with him. For instance, we were rather upset by Bronsted’s change in the meaning of the word acid and we discussed some kind of a different proposal for a definition of acid. It’s perfectly clear what a base is; it’s anything that can add a proton, but what you get when you add a proton to a base is something else again. Bronsted wanted to call ammonium ion an acid, for instance, and we were bothered by that. I had some correspondence with Conant about this. Well, then the war came along. I really felt it was terribly important to get into it. I met Kistiakowsky. He was giving a lecture at Columbia and I knew he was building up a war time research group. This was early ‘41 before we were in the war, and I said I was very anxious to get into war time work. Of course, I knew this uranium stuff was beginning to get hot around Columbia; the nuclear stuff. I even had some ideas about that; for example, the possibility of using the complex derivatives of uranium; some of them are volatile. It turned out that they used the fluoride, but there are some neutral complexes that are reasonably volatile that might have been used. I’m sure they were looked into. At any rate, I hadn’t gotten involved in it, although I knew Urey well and we were on good terms and I knew he was starting to work on it. Instead, the Conant Bush group sent me over to England to learn what the British were doing in war time research and I spent a good deal of the summer of ‘41 there. Then I came back and was assigned to the Explosive Research Laboratory at Pittsburgh.
Gortler:
What kind of things did you look at in England?
Hammett:
Probably everything that was going on. The British were completely open and didn’t have any kind of subdivision of subjects. I was informed about things that later on I wasn’t informed about in this country. Like the proximity fuses, for instance. I learned about all of the work that was going on, but specifically about explosives work because I was a chemist and I was supposed to be checking up on things that might be related to explosives.
Gortler:
Had you had any background in explosives at all?
Hammett:
No.
Gortler:
So that would be brand new.
Hammett:
The first time I knowingly came near an explosive was when I was sent out to the Piccatinny Arsenal to learn something about what was going on out there. When I got into explosives work I realized that I’d been playing around at one time with methyl nitrate. I was working on the still somewhat mysterious phenomenon that nitrates hydrolyze very rapidly; probably a different mechanism of some sort. I don’t know. So I was playing around with methyl nitrate not realizing that it’s a very sensitive and dangerous explosive and just pouring the residues down the drain. Anyway, I got into explosives work and particularly on what we called composite explosives which were made with ammonium picrate, sodium nitrate and a binder. And these turned out to have some uses. I think we were a little behind but I think we contributed something; had a few patents.
Gortler:
How large was the group at that time?
Hammett:
There were about 100 technical people in the Bruceton laboratory. About half of them were working on propellants under y direct control didn’t have any direct involvement in the high explosive area, although it was part of the laboratory.
Gortler:
What was the general feeling at that time? Chemists had come from all over. How did you get them?
Hammett:
Well, we just recruited them. It wasn’t a terribly difficult job. We picked up most of these people before we were actually in the war. One chap had gotten interested in rocket propellants himself. His name was Bill McEwan and he was one of Conant’s students. He did some of that work on very weak bases, and got a Ph.D. with Conant. He, unfortunately, had inherited wealth and he was just lazing around doing nothing and he got interested in rockets. He tried to get a job with a group that was working on the bazooka rocket but the fellow who was in charge of that wouldn’t take him because he said “anybody who is stupid enough to be interested in rockets is probably a German spy.” So we got him. After the war Bill McEwan was working in California with people in the medical school there, but he didn’t have to earn any money.
Hammett:
We spent all my summers while I was in college at a cottage in Maine and we were near a big tutoring camp and one of the prominent teachers at that camp was James Flack Norris. I used to see the boys from that camp out on the lake but I didn’t know any of the people there. I didn’t even know Norris was there.
Gortler:
During the period that you were in Pittsburgh did you maintain any contact with Columbia? Did you have any students there at that time?
Hammett:
Yes. I think Foster was there during the war. We published his stuff after the war. But I think he was about the only one. I had an assistant working on a special project but it never produced very much and I didn’t have any real contact.
Gortler:
But the papers that you published in ‘42 and ‘43.
Hammett:
Those were work that was done before the war.
Gortler:
We’d talked about the lack of funding before the war. Did things open up pretty well after the war?
Hammett:
You had to push employers away. It was a complete change. I had a big project from the Navy and I could work on practically anything I wanted to. I only had to specify what the aim of the project was. I started out following up the temperature coefficient thing. I had a number of people who worked on that sort of thing and some of my post-docs were hired on that grant; Joe Levy and Bob Taft were two. Levy was one of Paul Bartlett’s students and he was responsible for one of the first studies of mechanism involving infrared absorption spectra. This was before you had fancy automatic infrared machines. Some of our people at Columbia had split beam infrared spectrometers with which you could determine the absorption at a particular frequency. He showed that one of the widely accepted mechanisms for the hydration of olefins didn’t apply. This again was a pioneer piece of work. Bob Taft is out at the University of California at Irvine.
Gortler:
Yes. Of course, he was involved in that same piece of work.
Hammett:
That’s right. Some of their other work involved temperature coefficients again. It led to some useful results but I don’t think very startling ones.
Gortler:
Did you serve on any grant review boards?
Hammett:
Oh, off and on, yes. And I refereed papers for the journals.
Gortler:
Were you on the editorial board...?
Hammett:
Not of any of the ACS journals. I was very active on the Committee in Professional Training. We went around a good deal and visited chemistry departments at universities. And largely through that I got elected to the Board of Directors of the Society and I was active in that for half a dozen years. In fact, I ended up as Chairman of the Board for one year, before I retired. I’d been Chairman of the Committee on Publications; I’d also been Chairman of the Committee on Grants and Awards when they set up the Petroleum Research Fund Project. I was involved in the transfer of the funds from Universal Oil Products to the Chemical Society which involved considerable litigation.
Gortler:
I take it the ACS must have gotten funds. How and why did that happen?
Hammett:
Well, do you know the history of the fund? Several of the big oil companies set up the Universal Oil Products Company as a joint project. Sometime before the war the Department of Justice finally decided that this constituted a restraint of trade and forced them to divest themselves of it. One of our active board members, the fellow who invented tetraethyl lead as a gas additive, Midgely (I think), was largely instrumental in persuading the companies to turn the ownership of UOP over to the American Chemical Society. For years Universal Oil Products was a flourishing organization, but didn’t produce any dividends. They plowed their profits back into the company, which probably was a good thing. While I was on the board it was decided that the Society could make more money if they sold the stock of the UOP and invested in a wide range of investments. It took special legal approval and there was some litigation involved. Ultimately they sold the UOP stock and the proceeds were invested and led to the income which enabled the Society to set up the Petroleum Research Fund. The Petroleum Research Fund had to be, by the terms of the deeded gift, devoted to scientific investigations related to the petroleum field, but nobody ever objected to our deciding, rather broadly, what the petroleum field was. It included almost anything in physical organic chemistry, for instance. But I never had any direct money from them. It wouldn’t have been proper. This is the kind of thing that did go on during the period that I was there. At the same time, I was Chairman of the department at Columbia and got heavily involved in all kinds of things there and after six years of that, I was put in charge of the Committee on Government Aided Research at Columbia. I got into disagreements with the dean of the engineering school, John Dunning, about what kind of engineering research work was proper to do under government aided research. Finally, the president of the university overruled me on one of Dunning’s projects. I resigned from the committee. So I was busy but not terribly active in research for a good deal of that period. I never wanted to be an administrative officer. Of course, I was at Bruceton. I was very much in charge of the research of the laboratory and responsible for the personnel and everything else. The only offers I ever had to go anywhere but Columbia came from institutions that wanted me to be department chairman and I always turned them down. I didn’t want to be a department chairman. Arthur Thomas had been made acting chairman of the department while Urey was on the Manhattan District Project. Urey came back and Urey wanted the job of being chairman of the department again. This was while I was still out at Bruceton. By that time the attitude of the university administration toward department chairmanships had changed and to a large extent it was a rotating job; a job that nobody wanted but was important. Before the war ended the department voted in favor of Thomas and Urey went to Chicago along with Joe Mayer and a lot of people from the physics side, Fermi and company. After a few years, however, some of the staff of the department sort of insisted that I run as a candidate for the chairmanship. I did and was elected chairman, or actually, nominated, the appointment, in fact, came from the president of the university. So I got into it without really wanting to and it slowed my research down, I’m sure, because it was a heavy administrative load.
Gortler:
I looked at the Columbia catalog for ‘43 to ‘45 and then I looked again for ‘49 to ‘50 and noticed that a whole host of people left or died or retired in the period right after the war.
Hammett:
Most of them retired. As long as Butler was President, and was getting along in years, the university had…
Hammett:
…no stated retirement policy and mostly people just didn’t retire. It was almost direct evidence of disapproval by the Trustees if somebody was retired. Then after Butler lost control or was sick, I’ve forgotten, exactly, the university policy changed and they put in effect a fixed retirement age policy, 68. A lot of the staff of the chemistry department were over 68. This knocked them all out. It nearly broke the heart of some of them. They never thought that this was going to happen. It had been practically an insult to be retired. It was awfully hard on Beans; terribly hard on Nelson. Nelson, however, was appointed as curator of the Chemistry Museum and he had a lot of fun working on that. It kept him busy and occupied. He’d always been interested in history of chemistry anyway. But it was a harsh situation. Nobody at the university had made any preparation to recruit new staff. In fact, Thomas told me that Pegram, who was dean of the graduate faculty, had said, “Oh, don’t worry, we can always get staff.” Actually while I was at Bruceton, before I came back to the university, I’d written in reporting that the industry was very actively recruiting young chemists. They’d been around to Bruceton looking for chemists and I knew that the universities had better get busy and be active themselves and Thomas said, “No, the administration says,” the administration was Pegram, “the administration says you don’t need to worry, we can always get staff.” So they didn’t and we had to rush around hiring new staff. This is when Dailey and Ralph Halford and George Fraenkel were all added. Now some of the younger men were still there. Thomas was and Beckman and Dawson, but you see with Urey and Mayer going off to Chicago and all of these retirements we were pretty low on staff. During the war they had picked up Doering and Curtin.
Gortler:
For some reason or another I have an A. C. Cope on there at one time before ‘45. Is that the same Arthur Cope? Was he at Columbia at one time?
Hammett:
He was, briefly, during my absence. I knew Cope well because he was on the Committee on Professional Training and we worked together and he was on the board of directors of the ACS when I was on it. Now Bob Elderfield was there and George Kimball. They were both there before the war. They were on leave during the war like myself and came back after the war.
Gortler:
Is it conceivable that Cope came in to work on the Manhattan Project?
Hammett:
I don’t think he would then have been listed as a staff member. I mean Libby isn’t listed there, and he was there on the Manhattan Project.
Gortler:
Tell me a little about George Walden. He was a friend of yours. You published some papers with him. He was at Columbia from at least 1920, but he was never promoted past assistant professor.
Hammett:
George and his wife were friends of ours. He had been in the Pittsburgh laboratory and actually came to Columbia a year before I did. He was strongly influenced by Beans. Remember, Beans had a paper rejected by A. B. Lamb and refused to publish after that. This influenced Walden as well and he didn’t publish. I was influenced by Beans, also, but not in this area. At one time we thought Walden was on the verge of discovering a new transition element, but it didn’t pan out. He continued to teach at Columbia until the war, then had a job with Esso in Louisiana and didn’t return after the war.
Gortler:
Was Columbia willing to keep him all those years without promoting him?
Hammett:
Yes. In those days Columbia wasn’t so concerned about people staying on without tenure.
Gortler:
Can you tell me a little about the philosophy of the department while you were chairman.
Hammett:
All right. Well, I think one of the main opinions I had was that it was very important for a department which wasn’t going to expand, and we didn’t think we would, to maintain a reasonable age distribution. To some extent I may have learned this from Conant when I was on some ad hoc committees at Harvard to consider new appointments there, but I heartily agreed with the principle and I propagandized it in other places. In fact, I told the president of the Union Carbide Company once that they ought to maintain their Tarrytown Research Laboratory with a proper age distribution. I was complimented on telling him something that he ought to have known about business organization. But this made trouble because we had a rather unbalanced department, we had too many young men and when Doering and Elderfield and Curtin left and we were completely empty of organic chemists, I wanted to get older people instead of promoting younger people. We had some very good instructors. Dick Noyes, for instance, who’s made a success of himself, and Fausto Ramirez, who has been at the Stony Brook branch of the State University of New York, and there was another young instructor. I just had to tell several of these people that while we appreciated the high quality of their work, there wasn’t a spot for them because they were too young. We brought in Walling and Stork and that gave us a better distribution. I think that was important. Outside of that I didn’t care whether a man had been educated at Columbia or came from somewhere else. I wanted the best quality people we could get.
Gortler:
I think Breslow must have been hired during this period.
Hammett:
Yes, Breslow was hired then. Stork tipped us off to Breslow. Stork had known him at Harvard and I was able to do some finagling. I’ve forgotten the deal, but we had some money from one of the chemical companies, I won’t try to name it because I don’t want to be unjust, which could be used most any way provided it was used for research. So we put Breslow’s salary on that for a year and just had him do research without any teaching until there was a vacancy and we could appoint him to an instructorship. The appointment was very fortunate because he’s done awfully well and he stuck by Columbia in spite of offers from other institutions.
Gortler:
There were a number of lures put out as I remember. I think a number of us were surprised when he didn’t pick up some of them.
Hammett:
Well, you probably know.
Gortler:
There were always the rumors that I heard about.
Hammett:
I tried to get Westheimer actually because Westheimer had been in the Bruceton laboratories, and I knew him. Of course, he’d done post doctorate work at Columbia too. I knew him and respected his abilities very highly. We tried very hard to get him but he was quite happy at Chicago.
Gortler:
The rumor was that if he was going to leave the neighborhood around the University of Chicago, he didn’t want to go to a similar neighborhood at Columbia.
Hammett:
I don’t know whether Cambridge is much better.
Gortler:
When he went I think it probably was. You seemed to have a fair amount of success in recruiting because there are a number of very good people listed here who must have come around that time; Willy Reinmuth and Martin Karplus, for example.
Hammett:
That’s right.
Gortler:
I don’t know if Tom Katz was hired after your chairmanship.
Hammett:
I think I was chairman when he was hired. Just about the last year of my incumbency, or maybe it was the year after I left the chairmanship. Tom’s done very well.
Gortler:
We were in graduate school together and I was pleased to see how well he’s done. You served on a number of presidential boards. There was a Panel on Scientific Information of the President’s Science Advisory Committee. What was that all about and how were you chosen for that?
Hammett:
I don’t know. This panel was very largely concerned with scientific information and passing on scientific communications and I had been active in the Publications Committee of the ACS. I suppose people knew about that. I was the only real chemist in the group, so I’d stand up for chemistry and Chemical Abstracts as a means of communication and so forth. There were a lot of bright people on the panel. The present president of Bell Telephone Labs, and Weinberg, who was at the Oak Ridge Laboratory, and Joshua Lederberg, who got the Nobel Prize, he’s at Stanford now. They were good people.
Gortler:
What were your priorities on that particular committee?
Hammett:
To make recommendations to the government about the best methods of fostering scientific communication.
Gortler:
I asked you about your early consulting before and you said you picked up positions here and there just to make ends meet. You started that relatively early in your career. Later on you spent some time with Rohm and Haas, and then with Union Carbide.
Hammett:
The Rohm and Haas connection came through Ralph Connor, who’d been chairman of the Division of Chemistry and Chemical Technology of the Office of Scientific Research and Development under which our lab at Bruceton operated. When Kistiakowsky went to Los Alamos, Connor was put in as chairman in his stead. Connor had previously been at the University of Pennsylvania and had made contacts at Rohm and Haas then. At the end of the war he became head of their research laboratory and afterwards he was chairman of the board of directors of the company. He was an important, influential officer of the company and he was largely responsible for getting me that position. That started shortly after the war, and was quite profitable.
Gortler:
Were you retained on a daily basis or a yearly basis?
Hammett:
So much per day. It started out at a modest fee and ended up with a rather good one.
Gortler:
That’s always nice.
Hammett:
I kept that up till sometime after I retired from the university. We were living up in Northern New Jersey and I would drive down for a day or two to Rohm and Haas. The background of the Union Carbide thing is interesting. Ray Crist, who’d been on the Columbia staff before the war, had gotten into the Manhattan Project. It was a funny situation because I’m sure that his whole idea of a career was university life, but he got into a Manhattan District job and was put into administrative work and showed a rather remarkable ability for it. After the war he was unhappy and dissatisfied because Urey and some of the other people had left Columbia, so he went to work with Carbide. The first job he had with Carbide was running an automatic coal mining machine. About the time I retired he was research director of the Carbide Research Laboratory at Tarrytown and the laboratory had some money for hiring outside visiting consultants. This was a full time job and I spent three months up there. This was educational for me in a good many ways. I hadn’t been thinking enough about research projects and up there I did. I mean that’s when I began to appreciate the importance of the different H rate functions because there was a man up there who was doing work on one of them. I finally came to and realized how important these differences were. That was quite illuminating. Talking to people there stirred me up. That’s mostly what the job was, sitting around talking to people.
Gortler:
You were supposed to stir them up too.
Hammett:
Maybe. Hope so.
Gortler:
Did you consult for anyone else during the period after you retired?
Hammett:
No. I had a number of visiting professorships but they weren’t consulting jobs.
Gortler:
At any time did you feel that the consulting for Rohm and Haas influenced the research you were doing?
Hammett:
Yes. It tipped me off on the possibility of catalysis by ion exchange resins.
Gortler:
That was the next thing I was going to ask you about.
Hammett:
It was from that consulting work that I learned about the possibility and it led to a number of research projects.
Gortler:
One of the papers you asked me to look at had to do with using the polystyrene-sulfonic acid resins as catalysts.
Hammett:
Well, yes. I guess that was the Bernhard paper.[15] Bernhard went into biological Work, did post-doctoral work with Pauling. I’ve lost track of him but I know he’s in biological work still; a good man, a very bright chap. Other people who worked on that were Haskell, Peter Riesz, Samelson, and Catherine Chen. Most of these people were working on a Navy contract, the same Navy contract as Taft and the other people were on. We switched the central subject into the ion exchange catalysis.
Gortler:
You received a very large number of awards, most of the major ones in the country. Were there any that were more rewarding for you, some that you felt particularly moved by?
Hammett:
Well, of course, the National Medal of Science. This is kind of a big feather in the hat. Actually awarded by the president and awarded on the recommendation of a committee of distinguished scientists. Although I don’t know that I’d rate that so much higher than some of the others. The Willard Gibbs Medal is certainly a distinguished award.
Gortler:
You’ve written about, but we haven’t talked about, the contributions which you felt you made that were really the most important ones; the ones that gave you the greatest satisfaction in your career. I don’t know how you want to approach it.
Hammett:
Well, do you have the list?
Gortler:
I think the ones that you wrote about were your work. on acidity, the acidity function, the Hammett equation, and, of course, the book, “Physical Organic Chemistry.”
Hammett:
Well, certainly the theory of acidity was a pioneering piece of work and Hantzsch, whom I admired very greatly, wrote and complimented me on it. That was very satisfying. All of the work that Deyrup did, the acidity functions and the things that grew out of it, for instance, the study of weak bases, were important and certainly pioneering. The Pfluger paper on the addition of methyl esters to trim ethylamine, I think, was a very important piece of work. The Hammett and Paul work was, you might say, a sequel to the Deyrup work. I wouldn’t say it was as important. The Flexser paper, of course, on the determination of ionization by ultraviolet spectrophotometry was a very important piece of work, I think, and very satisfying. Certainly Flexser did an awful lot of hard work. The Wooten and Hammett paper, I think, was very important. It showed that when you change the medium the effect on different kinds of acids is quite different. And paper #36 on the effect of structure on the reactions of organic compounds, benzene derivatives, I think is very satisfactory. I did a lot of hard work on that.
Gortler:
It managed to keep physical organic chemists in business for another thirty years.
Hammett:
Walling wrote me recently that they were still getting lots of papers submitted on the Hammett equation and on the acidity function. That’s a satisfaction. I think the Steigman paper on the Walden Inversion was a very valuable and important paper as was the Farinacci one about the same time, which was the water catalysis and the alcoholysis of benzhydryl chloride.
Hammett:
I think the three Zucker papers were quite important because they were an in depth study of an important reaction from the point of view of rate, and the point of view of effect of structure on reactivity. And the Price paper, I think, is very important because it showed that you couldn’t count on entropy effects paralleling free energy effects.
Gortler:
You have mentioned several times that your general attitude was to proceed from experiment to theory as opposed to deduction from theory I think, in that James Flack Norris Award address, you mentioned the concept of empirical generalization. I think, there it was in regard to the Hammett equation.
Hammett:
I said something like that several times. In the address I gave when I got the Willard Gibbs Medal in Chicago, I emphasized that point, and of course, again in the introduction to the 1970 edition of “Physical Organic Chemistry.”
Gortler:
You didn’t feel, in any way, that that was anything to be ashamed of, even though you were a physical chemist.
Hammett:
I had checked the paper with Levy, Taft and Aaron[16] on the hydration of gaseous isobutene. That’s an important paper, and I checked the Bernhard paper on specific effects by ion exchange. I checked the Van Looy paper which cleared up a good many of the complicated situations that you get into in a non-hydrolytic medium. I think that was quite illuminating.
Gortler:
That was just about your last real experimental paper.
Hammett:
I guess it was the last. The actual last experimental work, not necessarily in terms of publication, was done by the last Ph.D. student I had, Robert Burnett. He did good work. I did a lot of work using this stirred flow reactor (some by Burnett). I was fascinated by it as a method of getting highly accurate rate measurements. The traditional method of measuring a rate is to determine the extent of the reaction at intervals of time and then to plot some kind of a curve and try to get the slope of the curve. Now in the stirred flow reactor you directly measure the rate. In other words you directly determine what would otherwise be the slope of a curve. The concentration of any reactant or reaction product in the stirred flow reactor measures the rate of the reaction which can be set equal to certain fixed coefficients times the actual rate. So in a way it’s a method of differentiation of getting the slope directly instead of measuring intervals on a curve.
Gortler:
I see. Was this something you developed?
Hammett:
The idea came from a British chemist, Denbigh. It was published originally in the Transactions of the Faraday Society. He never followed it up very much and I did. I developed various techniques for using it. I had quite a few papers using this method. They were all aimed at the idea of getting more direct measurements, inherently more accurate because you were measuring the rate directly instead of intervals from which you determine the rate by taking the slope.
Gortler:
You had gotten in on the ground floor of a number of instrumental developments; the UV spectroscopic work and the IR which we mentioned just a few minutes ago, and the stirred flow reactor. Are there any other instrumental developments that you were either engaged in or developed?
Hammett:
I don’t think so.
Gortler:
Certainly these were very, very important ones. How did you feel about the problem of teaching versus research? Did one ever take away from the other? Did you think they were both useful to one another?
Hammett:
Well, certainly as far as my career is concerned, they did complement each other. I got ideas for research out of teaching many times. And I certainly picked up research students because they were attracted to me because of my teaching. I am very much in favor of a research man doing teaching. I think I was a pretty good teacher. I enjoyed it, I really did.
Gortler:
It always seemed a challenge for you to get across your ideas. That was clear in your writing.
Hammett:
That’s right.
Gortler:
Do you have any advice for young people entering science today? Where they might best go in terms of where the future lies in science.
Hammett:
Well, I think you have to start out with the recognition that young people who’ve been through our educational system and get a Ph.D. desperately want a job where they can do research. Here is a good example. One young fellow came to us from an undergraduate college in Wisconsin. His father had been a life- long teacher there. When he came to do graduate work at Columbia he was determined to go into that kind of work. He wanted to be a teacher. But when he left he also wanted to do research. We spoiled him. On the other hand, it’s pretty obvious, if you look at it at all, that something like nine-tenths of the people who get Ph.D.’s in chemistry go into industry. Now I don’t know what the answer to that problem is but it’s a tough problem because you have a demand supply difference. It just isn’t easy to solve.
Gortler:
I know that we’ve been thinking about something you were exposed to in 1913 or 1914: An industrial chemistry course. We just don’t orient our students in that direction any longer. And I wonder if that might be something we really should look at more closely.
Hammett:
Well, I’m sure that it was a useful course for me. It taught me a lot about the possibility of chemical work in industry and then I had this First World War experience where I was very much in contact with industrial products. Beans always said, Beans again influenced me a good deal, if he was going to advise a young man about starting a career in chemistry, he would advise him to get a job with a company that’s never used chemists before, because that’s where the opportunities are. Then I also had the industrial development work that I did immediately after that war, the dye stuffs and pharmaceuticals. So I had some understanding of industrial research and industrial problems.
Gortler:
I was wondering whether it would be more realistic for the people in the academic world to either orient or expose their students to industry since nine-tenths of them end up in industry anyway.
Hammett:
It probably would. Of course in 1915 or ‘16 there was much less chemistry in industry than there is now. It wasn’t diffused as widely. I think it would be a more difficult job now producing a good industrial chemistry course.
Gortler:
Did your expectations of your students change at all during the years? Did you expect anything different from your students?
Hammett:
No. I always expected them to do well and they did. I had very good students. I had a couple who collapsed, yes. They never finished their work. But most of them were enthusiastic and industrious and able particularly in the post war period. The boys that came back from the war were the best we ever had.
Gortler:
That seemed to be the heyday of every good university in the country.
Hammett:
It certainly was. And many of them had undergraduate records that would never have gotten them into graduate school at Columbia before the war. They’d just grown up. Some of them did extremely well.
Gortler:
In one of your speeches you mentioned Bodenstein, and his influence on organic chemists in kinetics business. I suspect another person whom you probably had some close contact with was Eyring.
Hammett:
Oh yes. It was only a good deal later that I knew Eyring. His work and the work of Polanyi, of course, influenced me a great deal. What Bodenstein did, of course, was to set up the reactive intermediate principle, the steady state technique. It’s a mathematical technique but a very useful one. And it probably influenced people to take the idea of an intermediate that you couldn’t directly detect seriously. This was in, what you might call the culture of gas reactions. How much direct influence it had on reactions in solutions is hard to say, although certainly the people who were beginning to be active in the early ‘30’s knew about it and used it, Paul Bartlett, typically.
Gortler:
And Eyring’s transition state approach.
Hammett:
Yes. That, of course, is very important. I had a little uncertainty, in my own mind anyway, as to how much of that transition state idea came from Polanyi and how much came from Eyring. Eyring, I guess, deserves the credit for the transition state idea. But Polanyi certainly was responsible for the idea of an inversion in a displacement reaction and for the idea of a possible parallelism between rate and equilibrium. That comes off some of Polanyi’s work on gas reactions. I think that’s essentially what was bothering me. Polanyi was studying things like the reaction of sodium vapor with an alkyl halide. But the actual extension to the transition state theory, I think, is Eyring’s contribution. Of course Eyring was working with Polanyi on some kind of a fellowship. It was in Polanyi’s laboratory when he first developed that idea.
Gortler:
Yes, he mentioned that in an interview not too long ago. You obviously cared a great deal for students and kept in touch with them afterwards as well. Did you ever think of your influence on them as a person, that is, did you think of yourself as influencing them in more ways than just scientific influence?
Hammett:
I would think so.
Gortler:
You did know that you were doing that?
Hammett:
Yes. I didn’t do it deliberately but certainly they must have been influenced, just by osmosis so to speak. They remained in touch with me. I just got a new textbook from Fred Lowenheim. He’s written a textbook on electroplating. He’s been a devoted admirer. Joe Gettler, who’s been at Brooklyn Poly has kept in touch with me. He was at New York University, Uptown, and then they joined with Brooklyn Polytech and he’s still there. I get a letter from him every once in a while telling me how he’s getting on. He’s grateful to me. I helped him get a job. They keep in touch.
Gortler:
I did want to ask you a little bit about those things that you did outside of working hours. You do have some interesting hobbies.
Hammett:
Well, I tried vainly to play golf, and the more I tried the worse I got. We rented quarters in a summer colony on the edge of the Poconos near the Delaware River. We went out there for a good many years. I puttered around playing golf a little. Mostly I stuck my nose to the grindstone pretty much until I retired. Then I relaxed, and we traveled a good deal. We had a home in Sussex County and I had a big garden and grew all kinds of things. We grew fruits and berries. I had dwarf fruit trees and all kinds of vegetables. I had two successive asparagus beds that were worn out. It takes about fifteen years to wear out an asparagus bed but I did. Janet said, when I was writing that 1970 book, that she’d hear the typewriter going where I was working and then she’d not hear it and find out I was out hoeing in the garden. It was a good relaxation. For years I had an amateur interest in archeology and we visited places of archeological interest a good deal. We took this Swann cruise trip to the Greek and Carthaginian sites around the Mediterranean. Later on we took another Mediterranean cruise and we went up river in Egypt and we went all around Palestine. We went to Crete twice. We went to Malta twice. There are some fascinating archeological remains in Malta and they just relearned how to date them by revising the hydrogen isotope dating scheme using the tree ring dating. They put the Malta temples back several hundred years because the hydrogen isotope dating was wrong. It’s been revised. We went to Carcassonne, in France. There’s a medieval city there that’s fascinating. We went to Avignon; we went to the Lascaux Caves in the Dordogne Valley, which have these paleolithic cave paintings. Never got to Stonehenge. I’ve tried to go to places like that. I’ve been interested but purely as an amateur. I’m not in any sense an expert. I’ve been fascinated by the continental drift theory, so I read about it and try to keep in touch. And I have an interest in political matters. I generally read. I’m not very active physically any more but I was. When I had a garden I was active.
Gortler:
Sounds like you were. A crystal ball question. What do you see in the future for science in general, and for physical organic chemistry in particular? And maybe to induce you to talk, I had a talk with Phil Skell several months back, and his comment was that physical organic chemistry is dead. That people are just sort of picking up. We’re filling in the little numbers right now. I wondered if you think there’s some kind of future for physical organic chemistry.
Hammett:
It may be dead. I’m not close enough to it. Take the thing that my grandson, Dirk Zwemer, is working on. He’s working with a fellow at Berkeley who is using modern high vacuum techniques to study the properties of catalysts for gaseous reaction. There are all kinds of fancy new techniques. There are people who are worrying, and I think with some prospects of usefulness, about such questions as how you get from the reactants to the transition state. They study details of those processes with things like molecular beam reactions. I think there are lots of things still to do, but to some extent, well to a considerable extent, they depend on new techniques. I don’t agree with Skell. I know Skell very well. He was at Penn State when I was there. I have a good deal of admiration for some of his work.
Gortler:
He just felt that somehow we were putting more decimal points on now. I suspect there’s a fair amount of that.
Hammett:
That’s a possibility. As far as chemistry in general goes, golly, I’m reminded of a time when Charles Beckmann was leaning towards biological problems and a student came in to talk to me about something and I think Beckmann came up. The question arose why I didn’t go into biological problems, or biological chemical problems. And I said, “I’m just too old to start anything new.” And she said, “Oh, you’re not too old.” Well, Frank Westheimer was a good example. Now he’s moved very definitely into biochemistry. He was very clearly a physical organic chemist. He started out that way, and he did some important work. He showed things like the inversion of configuration on a biologically active molecule.
Gortler:
Yes, but that was very early work.
Hammett:
Yes, that was back before the war[17] but that showed the direction in which he was moving. He’s moved very far in that direction. I’m inclined to think that that is a tremendously important, useful, prospect for science because the tools are improving all the time. The minutiae with which they can study the constituents of cells just amazes me. It’s fascinating. And the reactions in situ. I think this is a very exciting area. If I was starting over again I might tend in that direction. Frank Westheimer is a good deal younger than I am.
Gortler:
He’s retiring this year.
Hammett:
Is he? I retired almost two decades ago.
Gortler:
Anything you can think of that we’ve left out?
Hammett:
At this point I feel fairly empty.
Gortler:
I just have a question to ask you for my own benefit and that’s can you think of anyone else that I might talk to that could help me out on the early days of physical organic chemistry?
Hammett:
Bob Taft, Arnett. You know where they both are. Arnett’s at Pittsburgh.
Gortler:
I know Ned Arnett.
Hammett:
Incidentally, Arnett got a very nice prize the other day. I’m glad to see him get it. Let me look at my hook, look at the index and see.
Gortler:
Well, if there’s one or two out of the country, it would give me a good excuse to travel.
Hammett:
Well, Bunnett, I think, would be worth talking to. He’s been very much interested in things like this. Webster, in Holland, I think is a very interesting fellow. I don’t know whether R. P. Bell is still alive; he’s in England. Deno, I think, at Penn State might be interesting to you. Ernie Grunwald is very well informed and an interesting person and Jencks who is also at Brandeis. Jencks has an MD and he doesn’t have a Ph.D. and now he’s working on reaction mechanisms. He’s a very good man.
Gortler:
Enormous contributions.
Hammett:
I think very highly of him. Is Koithoff still alive?
Gortler:
I don’t know.
Hammett:
I don’t know either. Again I’ve had a good deal of contact with Koithoff. Leffler might be interesting, Frank Long at Cornell and W. G. Young at UCLA. That’s about all I can think of.
Gortler:
Mrs. Hammett, since you’re here, would you mind talking to me for just a couple of minutes? I wanted to ask you a couple of questions too. I know that you weren’t a chemist.
Mrs. Hammett:
I’m not scientifically minded. I was interested in languages and that sort of thing.
Gortler:
I wondered if you could comment on what effect Louis’ career has had on your life.
Mrs. Hammett:
Well, it’s been my life really. I think I have a very poor understanding of science, but I think I know a bit about how scientists tick. What makes their minds go the way they do.
Gortler:
Can you tell me in some concise way what you think makes them tick?
Mrs. Hammett:
They are very exact, for instance. If I ask my husband what time it is, he’ll tell me it’s 33 and a half minutes past two. Things like that. They have to be very exact. I like to exaggerate a bit and I always get caught when I do it, not unpleasantly, but reminded that it wasn’t just that way.
Gortler:
Do you think a lot of your activities were oriented around his career?
Mrs. Hammett:
Yes, although we didn’t travel very far or very much when we were young. I think you [Hammett] only had two sabbaticals and both were spent right at home writing books or something. So we didn’t have much experience in travelling. In meeting chemists, I’ve always been very pleased to find they had so many interests outside of chemistry. Music seems to be one of the big ones. They’re all interested in music; they have collections and records. They couldn’t always play an instrument but they were very much interested in music, and in art museums and in all sorts of things. In fact, I remember one of the professors in the music department at Columbia said that their best, most critical audiences were scientists. They truly understood music better than anybody else. It wasn’t wholly emotional, it was something in their minds, the patterns and interweaving of fugues and things like that, they appreciated.
Gortler:
You mentioned earlier when we were chatting, that you spent enough time entertaining students. Did you have some contact with his students?
Hammett:
Yes, some. Not a great deal. Columbia was so large I didn’t see the undergraduate students very much, but we usually had the graduate students, their wives and so forth in our home, and the younger faculty when they came in. Sometimes the young wives were pretty lost in a big university like that, and they didn’t all live near the university. So we had them meet each other and get acquainted. We had a very socially happy group there. Being at Columbia, of course, they lived in the suburbs a good deal, and so we weren’t perhaps as close as we would have been in a small university town, but we got along beautifully.
Gortler:
What contributions do you think you made to his career? Not scientific contributions, but some other kind of support.
Hammett:
Well, he’d come home pretty tired, he couldn’t talk shop with me and I very carefully didn’t try to. Of course, we had our children and their interests. I went to my family’s home in Maine in the summer a great deal and he had to stay at Columbia and teach in the summers. We needed the extra income. So I’d take the children, when they were very little, and go to Maine with them in the summers and then he’d come up for a while. That kept them busy and out of his way in the summer time anyway. It was kind of hard on us. We were apart a good deal in the summers. Later on we had a summer home and I think he enjoyed it. We were in Pennsylvania near the Pocono area and we rented a place on a little lake there for about 11 years, I think. So that got us out of the city. Then he did his duty as a father, taking the kids to museums and things like that. But that was not exactly his line of work.
Gortler:
Did you ever have a feeling of being left out because you weren’t a scientist?
Mrs. Hammett:
No. I had interests, I was doing things around the university, and I was working with the visiting nurse services in New York and I would volunteer to work with all sorts and kinds of things.
Hammett:
You were in a singing group.
Mrs. Hammett:
I sang with a group about 15 years; A women’s choral group in downtown New York. I had some interests outside.
Gortler:
When he was so much involved with the American Chemical Society you were also involved in the Ladies Committee.
Mrs. Hammett:
Well, I was his wife. Yes, I worked with the Ladies Committee, entertaining and one thing and another. Of course, I met a lot of the wives of professors in other universities and made personal acquaintances that I have to this day. We exchange Christmas cards anyway usually a letter once in a while. It’s somewhat similar to being in the Army or Navy where if you go to another university you are accepted, you have a ready-made situation that you fit right into. So you don’t feel lonely even if you’re in a strange university town, the people are always very kind, take you in and show you the ropes.
Gortler:
Are there any additions you’d like to make?
Mrs. Hammett:
None, except that I’ve had a very happy life. I have no complaints; I don’t feel a bit downtrodden. I know I’m supposed to, because I’ve been what’s known as a housewife, which is a word that isn’t used at all anymore. I had no career of my own, in other words, but I never felt left out, no. Many times I didn’t see him, very much, especially in the early years. He taught evenings, he taught Saturdays and he was doing his own lab work on Sundays, so it was kind of lonely at times, when the children were little and I couldn’t get out very far hut I never felt I was neglected, certainly.
Gortler:
Well, thank you both so much for all the time you’ve spent with me. I think this is going to be very useful for me and for other historians.
[1]Minute can be found in Hammett file.
[2]The papers, notes and manuscript for the second edition of "Physical Organic Chemistry" are now in the Columbia University archives.
[3]L. P. Hammett and H. L. Pfluger, “The Rate of Addition of Methyl Esters to Trimethylamine,” J.Am.Chem.Soc., 55, 4079 (1933).
[4]L. P. Hammett, “Some Relations Between Reaction Rates and Equilibrium Constants,” Chem.Rev., 17, 125 (1935).
[5]L. P. Hammett, “The Effect of Structure upon the Reactions of Organic Compounds, Benzene Derivatives.” J.Am.Chem.Soc., 59, 96 (1937).
[6]L. P. Hammett, “Linear Fee Energy Relationships in Rate and Equilibrium Phenomena,” Trans.Faraday Soc., 34, 156 (1938).
[7]Lists of graduate students, post-docs and publications are in Hammett file.
[8]See session 1 of Hammett interview.
[9]J. Steigman and L. P. Hammett, “The Walden Inversion: Configurational Effects in the Solvolytic Reactions of β-Phenylethyl Chloride,” J.Am.Chem.Soc., 59, 2536 (1937).
[10]M. A. Paul and F. A. Long, Chem.Rev., 57, 1 (1957).
[11]F. P. Price, Jr. and L. P. Hammett, “Effect of Structure on Reactivity of Carbonyl Compounds: Temperature Coefficients of Rate of Formation of Several Semicarbazones,” J.Am.Chem.Soc., 63, 2387 (1941).
[12]G. R. Lucas and L. P. Hammett, J.Am.Chem.Soc., 64, 1928.
[13]See list of publications.
[14]H. P. Treffers and L. P. Hammett, J.Am.Chem.Soc., 59, 1708 (1937).
[15]S. A. Bernhard and L. P. Hammett, “Specific Effects in Acid by Ion Exchange Resins. II. Hydrolysis of Esters in Water Solution,” J.Am.Chem.Soc., 75, 5834 (1953).
[16]Levy, Taft, Aaron and Hammett, J.Amer.Chem.Soc., 73, 3792 (1951).
[17]Both of us were wrong. Work we had in mind was published in 1951. Westheimer, et al, J.Am.Chem.Soc., 73, 2403 (1951).