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Oral History Transcript — Dr. Gordon MacDonald

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Interview with Dr. Gordon MacDonald
By Ronald E. Doel
At UCSD in La Jolla, California
March 18, 1994

open tab View abstract

Gordon MacDonald; March 18, 1994

ABSTRACT: Early life; study of chemistry and geology at Harvard University (1946-1950, AB); influence of Wendell Furry, John Rosenfeld, Jim Thompson, Francis Birch, Percy Bridgman, Cliff Frondell, Marlon Billings, R. A. Daly and Kirtley Mather. Harlow Shapley adn McCarthyism at Harvard University. Elected to Harvard Society of Fellows, sponsored by George Kennedy (1951-1952, AM; 1953-1954, Ph.D.). High pressure studies of jadeite. Arguments about continental drift theories of Jeffreys and Harold Urey's views of geochemical history. Assistant then Associate Professor at Massachusetts Institute of Technology (1954-1958); use of computers and time-series analysis and the influence of Steve Simpson. Discussions of geophysical research among King Hubbert, Tom Noland, Phil Abelson, Merle Tuve, and Bill Rubey. Research at Caltech with Fowler, Wasserberg, Greenstein, influence of Fred Hoyle. Editor of the Journal of Atmospheric Sciences. Relationship of cosmology to geophysics. Development of the National Center for Atmospheric Research. John Tukey's report on the greenhouse effect. Reaction to M's paper "How to Wreck the Environment". Early history of the Environmental Sciences Services Administration.

Transcript

Session I | Session II | Session III

Doel:

This is Ron Doel, and this is a continuing, second interview with Gordon MacDonald. We're recording this at UCSD in La Jolla, California. Today's date is March 18th, 1994. In the first interview, we talked a briefly about your move to MIT after completing your graduate work at Harvard and some of your early research. But one issue we didn't cover was the beginning of a high-pressure research that you did while at MIT, particularly the jadeite studies.

MacDonald:

Yes. The jadeite studies were a continuation of work that I had gotten started while still at Harvard in collaboration with Francis Birch. We put together the instrumentation, and my major responsibility in that undertaking was to use x-ray methods to identify the products that we put in. The press was capable of getting up to, oh, I would guess, 15,000 bars and certainly temperatures up to seven or eight hundred degrees Centigrade.

Doel:

That was a major advance in the amount of pressure since the early 1950s.

MacDonald:

That was a major advance in coupling both temperature and pressure. The instrument or the pressure device had a relatively large volume as compared to the anvil devices that were being developed just about the same time and that I worked on. During the summertimes when I was at MIT, I came out to UCLA to do a number of phase equilibria studies. But the sample contained a gram, maybe a couple of grams of chemicals so that you could really do a very good job both microscopically and using the x-ray techniques.

Doel:

Right. One of the main papers that you did was also with E. C. Robertson?

MacDonald:

Yes. Gene Robertson. The three of us were involved. Birch ran the Dunbar Laboratory. Gene Robertson was a full-time postdoc who had worked largely on mechanical properties of rocks, and then I came in with basically my interest on phase relations. The jadeite study was looking at trying to establish pressure temperature conditions under which eclogites form. Eclogites are a relatively rarely rock found in metamorphic terrains that contain jadeite and other minerals that at the time were thought to form under quite deep conditions.

Doel:

Right. About at the Moho level?

MacDonald:

Yes.

Doel:

That was one of the principal questions that you hoped to answer in your research?

MacDonald:

Yes. One of the things we were interested in was that the Mohorovicic discontinuity, whether it was a phase change or a chemical discontinuity. And so one of the aims of the study was to determine the phase boundary between albite, that is the sodium-end member of the feldspars and jadeite.

Doel:

At the time most geochemists still believed that it was a chemical change?

MacDonald:

Yes, that there was a chemical change. The evidence of course was not clear. One could argue from the evidence in existence at that time it could have gone either way, but we thought that this was an important mineral transition to look at, not only because of the geophysical implications, i.e., what is the lower boundary of the crust, but also to interpret metamorphic terrains, classical terrains in Finland that Eskola had investigated. There were scattered outcrops of eclogites in the Appalachians and other locations around the world. We felt that if we could put a boundary as to where these reactions take place, you could get some idea as to the depth of burial and the thermal conditions under which the metamorphism took place.

Doel:

If there were debates, who seemed to be the principal proponents of the alternative view, the chemical shift?

MacDonald:

Oh. The chemical reaction, many of the classical petrologists held that as you went on the cross near the surface you'd have granitic rocks; as you went down, the rocks would become more dense and go into basaltic, and then the Moho represented a transition between basalt and peridotites, which is an ultrabasic containing perknite and feldspars and perhaps a little olivine. The peridiotites were of course totally or were very olivine-rich, containing magnetite, chromite and other materials.

Doel:

Right. Were there people within the department at MIT who also held to that view?

MacDonald:

Yes. I think the traditional thinking, how Howard Fairbanks at MIT was more or less pretty much a classical petrologist. He would have advocated that point of view. Jim Thompson at Harvard was of course very much interested in determining the phase relations, and he was one of the people who pushed very hard and said that these kinds of studies have to be carried forward, and I think he was among those that would have favored the phase transition as a possible explanation of the Mohorovicic discontinuity.

Doel:

Right. I was just curious whether there was discussion within the department over, and the reception of the ideas that you proposes?

MacDonald:

Oh yes. There was a lot of discussion, and much of the work went forward in the summer before I started teaching. My teaching appointment of course started July 1, but I stayed on at Harvard, and Gene Robertson and I continued with the experimental work. Once September came and the teaching started, I spent much less time. I continued to do a little bit. We wrote up a paper and sent it off for publication. Basically most of the work was done the late spring of '54, the summer of '54, and some in the fall of '54.

Doel:

Were you teaching undergraduate as well as graduate students?

MacDonald:

No. The first year I taught there, there were graduate courses. There were a number of undergraduates that took it, but they were seniors and fairly advanced. And the major course I taught was on sort of the thermodynamics of minerals and trying to apply thermodynamics to mineral assemblages of all sorts, principally metamorphic and aqueous.

Doel:

You cite in your co-authored paper on the "Experimental Determination of Jadeite Stability Relations to 25,000 Bars"[1] the work that Loren Coes was doing.

MacDonald:

Yes.

Doel:

I was curious how you came to know of Coes?

MacDonald:

Well, we were very much interested. I had become convinced, I think largely as a result of Jim Thompson's observations, that quartz SiO2 could exist in a variety of different polymorphic forms. Quartz is a very open structure, a density of 2.76 or something like that. I don't remember exactly, but it's an open structure. The coordination number of the silicon is 4; that is, you've got four oxygens around each silicon, and one could, just looking at the geometry, think of other structures that were more dense. I was principally interested in a structure that contained six oxygens around the silicon, which eventually was discovered by a Russian now known as Stishovite. But just at about that time Loren Coes found an intermediate form of which the coordination number is intermediate between the four and the fully packed structure with the coordination number of six, and that's the mineral that came to be known as coesite. I later did some work at UCLA during the summers trying to outline the stability field of coesite.

Doel:

And this would have been in the very early 1960s?

MacDonald:

No. That was done during the years starting with the summer of '55. I spent every summer at UCLA.

Doel:

That's interesting to know.

MacDonald:

Yes. So '55, '56, '57 I came out to UCLA, spent the summer doing experimental work in the laboratory of George Kennedy, and the first, did a number of investigations, looked at the calcite-aragonite stability of phase relations, the quartz-coesite stability relations, and so forth.

Doel:

Right. That's good to know.

MacDonald:

But that work was done at UCLA, where we were working for the first time with the piston anvil kind of apparatus. George Kennedy had taken a lead trying to calibrate that instrument to try to make sure that the pressures that you calculated were somewhat in the line. And so did a lot of work on, as I say, during the summertime, come out here, work with George Kennedy, Dave Griggs, Leon Knopoff, and others.

Doel:

Right. I want to go into detail on the UCLA period in just a moment. I was curious when you mentioned the problem of determining the accuracy of measurements. Was that a major concern for you using the piston anvil?

MacDonald:

Yes. It was a major concern. You know how much force you exerted on the piston, you knew the area, but the issues, there were a number of uncertainties. One was the area that you calculated from just the size, was it really appropriate, or was the pressure sustained by some smaller area. And then another question that be-deviled us at the time was whether or not the pressure was isotropic, and whether the normal pressure, the pressure along the axis of the anvil, was equal to the pressure on the sides. And so I did a lot of calculations, and we did some measurements to try to convince ourselves that indeed conditions were more or less isotropic and that indeed the calculated pressure was appropriate. What Kennedy did was attempt a series of experiments to actually calibrate using Bridgman's data on a variety of properties of minerals obtained in a large pressure vessel and then compare them with the results that you obtained in the anvil device, and we eventually convinced ourselves I guess.

Doel:

You ?????? from the existing curves?

MacDonald:

Yes. We were getting pretty good estimates of the pressure. MIT, at that time, did not have any high-pressure equipment.

Doel:

Right.

MacDonald:

So the UCLA facilities were available, and that's why obviously Kennedy and Griggs wanted me to join them eventually and Birch, once we did the jadeite experiments and carried out a number of experiments unsuccessfully to try to make diamonds. Birch's interest turned elsewhere and not much further was done on mineral stability at Harvard.

Doel:

That's interesting. So that occurred during the time that you had the MIT appointment?

MacDonald:

Yes. That was the '54 through '58 time period.

Doel:

Was there also then a decrease in the use of the high-pressure apparatus at Harvard?

MacDonald:

It was just used for other purposes -- making measurements of conductivity, electrical conductivity of rocks or minerals, to measure their mechanical properties, with less interest on the phase relations. Birch's interest was much more physics rather than chemistry, and he really didn't want to get involved with the chemical details. The students he had at that time didn't have a background on x-ray identification of minerals and things of that sort. For a whole variety of reasons, the laboratory turned its interests towards measuring the physical properties of minerals.

Doel:

That's very interesting. I recall from our last interview that you were already quite close with George Kennedy and others at UCLA. One issue that comes to mind: given that this was just before 1957, did anyone in your department at MIT have particular interest in the IGY? Was any development there influenced by IGY activities?

MacDonald:

Absolutely not. In the geology department, I think Pat Hurley, who served on a number of international committees, and there was a professor of geology at MIT did mostly age dating, had some interest in IGY, but it was certainly peripheral. The meteorology department -- again, I don't remember any real participation on our talk about it. At UCLA, there was a great deal of interest. When I'd go out in the summer there was Joe Kaplan, who played a big role, and obviously I knew about it from my visits to Washington and Lloyd Berkner and other people who later left. But neither at Harvard nor at MIT was there much thought about IGY. My explanation for this is that IGY was largely pushed by people who had an interest in the upper atmosphere: Berkner of course, with ionospheric physics; Kaplan, high atmosphere or air glow. There was a much greater interest from that community of geophysics which is not represented at either MIT or Harvard, that both very strongly aimed at the solid earth at the time.

Doel:

The only exception, who comes to mind, in the astronomy department, is Fred Whipple.

MacDonald:

Yes. Fred Whipple in astronomy. But surprisingly there was very little interaction between astronomy and geology. The one person who for a brief time was in astronomy at Harvard and which I got to know and established a lifelong friendship was Tommy Gold. But he left very shortly and went on to Cornell. And he too was not involved in IGY. Fred Whipple of course was, and Donald Menzel also was involved.

Doel:

Did Tommy Gold talk to you about his experiences in working in the department? As you say, he didn't stay in the department very long.

MacDonald:

Yes. We talked at that time and since then, and he found himself not particularly welcome in the sense that Gold was very strongly pushing radio astronomy, pushing different kinds of science. Tommy, throughout his career, has been extremely innovative and unconventional in his approach to science, and I would say Menzel and Whipple, Shapley -- he was still around, and Gaposchkin were pretty much traditional astronomers. I think Gold's most interesting interactions were with the physicists -- Purcell, who was interested in looking at the 21 centimeter hydrogen line, and this resonated with Gold. But the astronomers were not completely receptive. It was not a happy marriage.

Doel:

And Bok, who had been the leader of radio astronomy at Harvard, was already gone?

MacDonald:

He had already gone, yes.

Doel:

At the time that Gold arrives.

MacDonald:

Mm-hmm [affirmative].

Doel:

I'm curious about your contacts with Lloyd Berkner. They also began around in the mid-50s?

MacDonald:

Yes, in the mid-50s. One of the positions I had while at MIT was an association with the Carnegie Institution of Washington, in particular their Geophysical Lab. And that meant that they would cover my expenses for trips down to Washington in which I'd visit the Geophysical Lab. And during those visits, I'd often attend seminars that were run by Bill Rubey. He was a highly influential geologist at that time. Rubey was a good friend of Berkner's, and Berkner participated in a number of those seminars. Harry Hess would come down frequently. Harry Hess and Lloyd Berkner were close. Both of them had been in the Navy. And so I was sort of on the outskirts of the group, a very young professor, but somebody who certainly appreciated the kinds of thinking and work that was going forward in the IGY, even though my own research interests at the time were simply at quite a distance from theirs.

Doel:

Mm-hmm [affirmative]. That brings a few things to mind. Berkner by then was moving increasingly into administration, but it sounds as if though he was very interested in the scientific details?

MacDonald:

His role was a promoter. He promoted the IGY, he was a very strong promoter of support of geophysical research. He was I guess certainly a leading force in eventual establishment of the National Center for Atmospheric Research. He knew his way around Washington from his days in the Navy, and he had many, many connections, particularly through being a member of the National Academy of Science and served on their council and so forth and so on. And he and Kaplan got along well and worked together.

Doel:

I imagine that Kaplan was not often at UCLA during the summers that you visited prior your appointment?

MacDonald:

He was there enough. I knew, you know, he had played a key role in setting up the Institute of Geophysics at UCLA.

Doel:

Yes.

MacDonald:

He didn't get the directorship and there was much bitterness after that, but I certainly got to know him, and learned something about the kinds of things he was interested in, and I got a very good feeling of what IGY was all about, both through Berkner and through Kaplan.

Doel:

Was that also a main topic when Bill Rubey and Harry Hess were together?

MacDonald:

It was one of those. It was the seminars, you know, there were these evening gatherings at Bill Rubey's house; we'd have a beer and somebody would give a talk and then a discussion would run on for hours. I gave several of them. Hess would give talks, Berkner certainly gave talks. There was just a wide variety.

Doel:

And how often did those sessions occur at Rubey's house?

MacDonald:

Every two weeks. Obviously I didn't attend all of them, but I came down for quite a number of them from Boston.

Doel:

Which presentations did you give yourself?

MacDonald:

Talking about phase relations and conjectures about the structure of mantle and crust. I was beginning to think about the thermal evolution of the earth. An early paper I did when I first went out to UCLA. Much of the work that was incorporated in the paper was actually carried out at MIT. The application of thermodynamics and trying to understand geologic processes. Another participant was King Hubbert, who was very, very sympathetic to this point of view.

Doel:

King Hubbert at that time lived down the street from Rubey.

MacDonald:

That's right, that's right. They were very close, and Hubbert I think was at almost all seminars. Tom Nolan, who was head of the U.S. Geological Survey, was there, Phil Abelson was a regular participant, again a close friend of Bill Rubey's.

Doel:

Right. Were any of those discussions or topics particularly memorable? Do any stand out?

MacDonald:

None of them -- I think all of them, there were always exciting, high quality, and the people involved were critical but not destructive. It was a group of people who got along very well and interacted in a highly positive way.

Doel:

Interesting. At those meetings, did Bill Rubey talk about his research in the origin and development of the oceans?

MacDonald:

Yes, he talked about that. He also talked about his geologic observations, eventually led you know to the papers of Rubey and Griggs on overthrust and so forth.

Doel:

Hubbert also played a role in this work, as I recall.

MacDonald:

A very important role. But it was a very enriching experience, and for a young person I found it extremely exciting. Also these people, or many of them, were involved in Washington science politics, and it was always interesting to talk about what was going on.

Doel:

It was a political education?

MacDonald:

That's right.

Doel:

How many people, roughly, came to those sessions?

MacDonald:

I'd say 12-15. Merle Tuve was another regular participant.

Doel:

So it drew heavily on the Carnegie Institution of Washington and the Geological Survey?

MacDonald:

The Carnegie and the Geological Survey. Those were the principals, and both the Geophysical Lab and the Department of Terrestrial Magnetism at Carnegie were involved.

Doel:

And how long were you down at the Geophysical Lab during those periods?

MacDonald:

I would come down and I guess during a year probably spend six weeks. [phone rings] Excuse me.

Doel:

[After break] In discussion with Kaplan and Berkner about the IGY, did the international problems in organizing the IGY come up?

MacDonald:

There were certainly discussions, and a very heavy emphasis on how to make sure that the Soviets were totally involved. And other discussions about making sure that the French played an important role. Those two countries were of particular concern, and I think Berkner worked very, very hard involving the Soviet Union.

Doel:

What were the concerns involving the French?

MacDonald:

The French I think initially -- my recollections are that they took a somewhat classical stand-offish point of view, but because of their interest or participation in Antarctic research, gradually were drawn in, and again through efforts of Lloyd Berkner.

Doel:

He played a key role at the international negotiations.

MacDonald:

Oh, he played a very important role, in terms of really getting countries to cooperate and to see the importance of some of these ventures. Kaplan was less effective, but he also played a key role.

Doel:

You mentioned that one of the research topics that you were doing at MIT before you went out to UCLA was the thermal history of the earth, which of course led to your major paper in 1958.

MacDonald:

Right.

Doel:

And that was a topic that you presented informally at Rubey's house?

MacDonald:

Yes, yes.

Doel:

I'm curious what the reactions were: clearly by the 50s there were different points of view on what the thermal history of the earth was branching out from Rancho Sante Fe.

MacDonald:

That's right. You know, there were very positive interactions. I recall Hess in particular was interested because he wanted to know. He clearly was interested in how near the melting temperature, rocks under, particularly under the oceans. He, even at that time, felt that convection was a very, very important process, and we argued about the role of convection and the transport of heat and so forth and so on.

Doel:

At that period of time you were not in favor of convection. I'm curious, was that a point that came up in discussion?

MacDonald:

Oh yes, yes, yes. I had reviewed the evidence and a few years later, I wrote a great deal about the geophysical evidence in support of a relatively rigid mantle.[2] Hess of course found all kinds of evidence to support the mobility concept. There was lots of discussion on that.

Doel:

Hess was corresponding closely with Urey at that point.

MacDonald:

Yes, yes.

Doel:

He had been interested in Urey's ideas from the early 50s. Did others take a role that you recall in those debates, or did it really seem to be between you and Hess?

MacDonald:

Hess and I were the principal protagonists or santagonist at that time. It was also the time -- and I can't set the exact time, but it was, let's see, Sputnik was in '57, so in '58 -- I met Bob Jastrow, who was then at the Goddard Institute for Space Science. And through Jastrow met Harold Urey, and for the next 15 years Harold and I were very close and ended up writing a major paper which nobody ever read, but nonetheless it was a-- [laughs]

Doel:

So that was the first time that you really met Urey?

MacDonald:

That's right.

Doel:

And it was in the Washington context rather than anything to do with geophysics.

MacDonald:

It was in the Washington context, and it was the context of Jastrow trying to identify a few people whom he could sort of put together to think about lunar and planetary explorations. Urey was obviously very well known, with his book on the moon and his abundant writings. My name came up because I had a broad range of interests, including some things that were relatively critical of some of Urey's conjectures, so Jastrow got us together.

Doel:

Jastrow began this about 1958?

MacDonald:

It was in '58. I think it was also in '58 that Urey, Jastrow and I appeared on a show that Walter Cronkite ran which was "The World Tomorrow" or something of that sort. Anyway, it was perhaps the first discussion over TV of lunar exploration. It was a half hour show that CBS put on.

Doel:

What were your views about lunar exploration?

MacDonald:

I was very enthusiastic. I felt we could learn a great deal about the earth by looking at the moon, and so I was eager to participate.

Doel:

I want to get back to both your connections with Jastrow and the beginnings of your lunar research and t comparisons you made with the earth. But it's probably better if we speak a little bit about the transition that you made between MIT and UCLA.

MacDonald:

Yes. The transition was relatively straightforward. I had been spending the summers out at UCLA. I found the very collegial and in many ways a richer intellectual life, at least in terms of the things that I was interested in, than at MIT. At MIT the people I interacted most with were my students. I had 12 or 15 Ph.D. student committees that I chaired while I was there, some of them went on to very distinguished careers.

Doel:

Who are you thinking of when you say that?

MacDonald:

Well, I'm thinking of, because I just missed his 65th birthday, Sven Treite, who went on to do very great things in seismic exploration. His thesis however was on the subject of attenuation of seismic waves.

Doel:

It was also one of your research interests.

MacDonald:

Yes, that's right. Dave Wones [?] was another, John Wood at the Smithsonian. They really very good students.

Doel:

Is this the John Wood that was also a for a time at the Smithsonian Astrophysics Observatory?

MacDonald:

Yes, yes. John Wood. He did his thesis on the petrology of meteorites.

Doel:

Just about the time that you left MIT, do you recall any discussion among the faculty about ways to reorient the department? Was that an issue actively being discussed?

MacDonald:

Yes, there was a lot of discussion. There were two major thrusts within the department. One was radioactive dating using potassium-argon and to some extent strontium-arubidium, and the senior faculty member, Pat Hurley, led that effort. But I didn't feel it was a comparable quality to work at other institutions. The second thrust was on interpretation, taking seismograms, digitizing them, and using the statistical techniques developed by Norbert Weiner to interpret them. Endess Robinson, Sven Treitel, Freeman Gilbert, another of my students, were the leaders in that activity. Even though I was not involved, Sven did his thesis with me and Freeman did his thesis with me. But I felt that was rather narrow and much too oriented in retrospective. Of course I was totally wrong, much too oriented toward servicing industry and perhaps not totally appropriate for academia. And I wanted to see the department broaden in geophysics in general. I had at that time made very good friends with the people in meteorology, Ed Lorenz, Jule Charney. I help set up and certainly participated in geophysical fluid dynamic seminars that were run at MIT in Woods Hole with Willie Malkus, Henry Stommel, and then I thought that the intellectual standards within let's say the meteorology department was represented by Charney and Lorenz and so forth were higher than the intellectual standards that we had in our geology department. Bob Shrock, who was chairman, was very sympathetic to my views. Undoubtedly if I'd have had the patience and stayed there we could have changed the department in the end. Of course it did change very greatly.

Doel:

But it was not until later that that change occurred at MIT?

MacDonald:

It was much, much later. There was a good deal of dead wood, older people or even people in the middle age who were no longer active in research. And so I felt that it wasn't as interesting a place as UCLA was, particularly for my interests. At the same time I had met Walter Munk. He had been at UCLA -- I mean at MIT -- and during the summers at UCLA I frequently came down to Scripps and we started talking about writing our book together.

Doel:

This is the book that eventually came out in 1960?

MacDonald:

In '60, yes, yes. So we started to think very seriously about that book, but it was until I moved out in '58 that we started to work on it.

Doel:

How did the idea of writing that book come together?

MacDonald:

It started after Walter gave a seminar on some facet of earth's rotation. I asked a number of what I thought were extremely critical questions, some of which we could deal with, some of which we couldn't. We got together after the seminars - it was common to have a drink -- and he said, "You seem to know something about this." I said, "No, I really don't know, but I'd like to learn a lot," and he said, "Well, why don't we think about putting our thoughts together?" That's the way it got started.

Doel:

Initially it didn't seem that it would become a book?

MacDonald:

No. Initially it was -- I think, and Walter I think agrees, although I'm not absolutely certain -- that it was I who said, "You've written a large number of papers on various subjects dealing with rotation. Shouldn't we try to put together coherent account?" He said, "I could never do that," and I said, "Well, I'll help you," and he said, "Fine." And that's the way the book idea got started.

Doel:

Who were the principal people that you talked to while you developed that book? Were there others in the astronomical community who were interested in rotation who contributed to it at all?

MacDonald:

It really was Walter and I put together.

Doel:

That's interesting.

MacDonald:

Walter of course had had a number of students, some of whom are still around, who had worked on facets of the subject.

Doel:

But it was principally not only a geophysical effort, but a very private effort just among yourselves?

MacDonald:

Yes.

Doel:

When you came out to UCLA and knew that it was on a permanent basis, what were your expectations? What did you see your particular position to be?

MacDonald:

I saw myself as being a researcher. I was pleased they made me a full professor with tenure before the age of 30 and so forth and so on, that I was somewhat concerned with the fact that I wasn't going to be associated with students. Louie Slichter used the argument, "The world is your class. You can write papers and you can influence people that way." I could see myself conducting a research program trying to branch out into new areas of geophysics. The work I did I had already started with Walter, you know, and work I'd done with Charney and Lorenz on geophysical fluid dynamics, but there are many problems that don't deal with the solid earth and that there are lots of things that one should be concerned about. I wanted to developed modeling. UCLA had a very large grant from IBM. Their computing facilities were at least as good as those of MIT, and access to them was a great deal easier because there wasn't as much competition to get onto the computer. Through the state there was support for research. You didn't have to be fighting for grants at the time.

Doel:

So it was less time-consuming for you to do your research?

MacDonald:

Less time consuming, and there were lots of interesting colleagues.

Doel:

And did you in fact though have any kind of routine contact with students, or in the institute appointment were you really fairly isolates from them?

MacDonald:

No. I had very little contact with students. At an early stage I contacted the physics department and said I'd be willing to teach in their graduate school. They said fine, so I used to teach a course in statistical mechanics and so had interaction with students in that way. Then I forget when it was, '62 or '63, we formed a department, and had a full teaching program. I had a large number of Ph.D. students.

Doel:

Louie Slichter in the mid-1950s was still interested in keeping some industrial funding coming into the Institute.

MacDonald:

Yes.

Doel:

Was that still a major factor at the time?

MacDonald:

It wasn't a major factor, but it was certainly an important factor. I remember visiting a number of the oil company laboratories, giving seminars, lectures and so forth, trying to maintain connection between the Institute of Geophysics and industry. And Louie Slichter did a fair amount of consulting in the geophysical industry and maintained good close contacts.

Doel:

How did other faculty members feel about that? Did it seem appropriate as a professional activity?

MacDonald:

It was -- he was alone and it certainly didn't interfere with his interests or the work he did for the institute. I don't recall any sort of critical comments on that.

Doel:

Interesting to hear that you also were involved in visiting geophysical ?????

MacDonald:

Yes. It was part of an outreach program to let them know the kinds of things that were going on in the Institute, and I'm sure Louie would then use that as a way of encouraging contributions.

Doel:

Did any of those informal talks lead to any sustained contacts of any kind?

MacDonald:

No, no, no.

Doel:

In the time we have left, I want to touch on your critical 1958 paper on the thermal history of the earth.[3] I'm wondering what reception it had.

MacDonald:

It certainly attracted a great deal of attention. To some extent it was not much of an advance over earlier work that Jeffreys and Slichter had done. The new components were that it explicitly took into account the fact that heat can be transferred not only through thermal conductivity but also through radiation and the fact that there was some of it evidence, largely developed at Harvard by Sid Clark [?], that minerals were transparent in the wavelength range which would be ??? at that time.

Doel:

Very long wavelengths.

MacDonald:

Yes, yes. And so but the transfer makes the problem nonlinear. So you can no longer obtain an analytical solution, so you have to go to numerical methods. And so the difference between what I'd done and what other people have done were to take into account for nonlinear conductivity, attempt to do a much better job of taking into account the variety of radioactive sources that have not only the various pieces of uranium, you have potassium, you've got thorium, and there one can play with models in which they are distributed in different ways and use in a computer. You can then investigate a much larger range that it would have been possible using classical analytical techniques. So it broke new ground. I think it was really the first paper dealing with the solid earth that constructed a model and then used a large computer to carry out the calculations.

Doel:

I misspoke earlier when I said that was 1958. It was actually published in 1959, this paper.

MacDonald:

I remember reading the proofs in December of '58.

Doel:

In that paper the critical values were derived from concentrations of uranium, potassium and so on in meteorite samples.

MacDonald:

That's right.

Doel:

And how much of an influence were astronomical determinations of the ?????? elements in your work?

MacDonald:

That was very important. Again, I'd gotten into that subject through my interactions with Urey, and had gotten rather deeply into the literature on the abundance of the elements and observations on how you both use meteorites, but also solar abundances and so forth and so on. And eventually, I think it was in the summer of '59 -- it may have been the summer of '58 -- I spent the summer at Caltech with the astronomers. That was the year that Hoyle and Fowler and the two Burbidges were working on their "Origin of the Elements" paper, and I followed that work very, very closely. And eventually Fowler and I and Wasserberg [?] wrote a paper. Some other things came out of that.

Doel:

Right. Wasserberg was already at Caltech at that point.

MacDonald:

He was there. Yes. My association was not with geology surprisingly; it was with the astronomers.

Doel:

That's interesting. And Jesse Greenstein was also at Caltech.

MacDonald:

Jesse was there.

Doel:

Did he contribute much to that development?

MacDonald:

He contributed a great deal in terms of keeping people straight on what the stellar abundances were and how to interpret those. The real sparkplug of course was Hoyle, who had a very deep understanding of the nuclear physics. Fowler contributed by the fact that -- [interruption...] --

Doel:

I'm afraid unfortunately we in this instance just about run out of time, but we clearly have many issues that I want to cover when we get a chance to do the next interview segment. And, as always, this tape nor the transcript will be released to anyone yet without your express knowledge and approval.

MacDonald:

Sure, sure.

[1]With E. C. Robertson & Francis Birch, American Journal of Science, 225 (1957): 115-137.

[2]"The Deep Structure of Continents", Rev. Geophysics 1 (1963): 587-665.

[3]"Calculations on the Thermal History of the Earth", J. Geophys. Res. 64 (1959): 1967-2000.

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