Oral History Transcript — Dr. M. King Hubbert
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M. King Hubbert; January 10, 1989
ABSTRACT: Born in Texas in 1903; influence of remote, rural environment on his upbringing and early education. Attended Weatherford Junior College until 1923; studies at University of Chicago, B.A. in 1926, M.A. in 1928, and Ph.D. (formally awarded) in 1937. Comments on courses, teachers and fellow students at Chicago, including J. Harlan Bretz and Rollin T. Chamberlin. Summer research at Amerada Petroleum Corporation (Oklahoma), Illinois State Geological Survey, and U.S. Geological Survey (USGS), late 1920s to early 1930s. First teaching position at Columbia University; research on ground-water motion; involvement in Technocracy Movement, 1930s. Marriage to Miriam Graddy Berry, 1938. Senior analyst on staff of Board of Economic Warfare, 1942-1943; deepening commitment to issue of natural resources. Thoughts on limited interactions between geologists and geophysicists; work in advisory committees on geophysics education, 1930s to 1940s. Theory of scale models, 1937; related research involving strength of solids. Career at Shell Oil Company and Shell Development Company, 1943-1964; directs research laboratory at Shell, perspectives on industry environment for scientific research. Lecture tours to geological, industrial, and policy groups, 1940s to 1960s; involvement in Atomic Energy Commission, National Academy of Sciences, National Research Council, advisory committees. Research with W. W. Rubey on overthrust faulting. Deepening interest in oil and natural gas reserves; responses from officials in petroleum corporations and federal government to his predictions of local, national, and worldwide reserves, 1950s to 1960s. Research geophysicist at USGS, 1964-1976, after retirement from Shell; studies of natural resources and conflicts over his conclusions involving other scientists at USGS. Visiting professorships at Stanford University, Johns Hopkins University, University of California, Berkeley, 1962-1977. Continued involvement in issue of geophysical education at American universities and in studies of natural resources, 1950s to 1970s.
Doel:In our last interview, you were talking about the experience you had with Bretz in Wisconsin, during your first field trip as an undergraduate. I'd be glad if you would continue that.
Hubbert:OK. We had begun to tell this story the last time. But I'll have to back up a minute for some things that I forgot to mention.
Doel:That will be fine.
Hubbert:The field course was to be during the month of September, 1925. The month was memorable in another respect. We'd had the Scopes Trial during that summer in Tennessee, which everybody was much worked up over.
Doel:You were reading the daily newspaper accounts?
Hubbert:Oh, of course. All right, back to this field course. Bretz had been on a different course out in Washington state. He came back to meet us in Baraboo where the camp site would be. I was driving the station wagon out from Chicago, which was our transportation. I mentioned before that when I first talked to Bretz about this in the spring, I raised the question of whether there were some things I could be reading during the summer. He said, "Not a thing. Not a thing."
Doel:He wanted you to be fresh.
Hubbert:Yes. And so when we assembled, that first day, my first job was setting up tents. We had one of these square tents for sleeping. We had another big tent which was the dining tent, and also the work tent, for our maps and so on. We had to set up those tents, and dig a pit for garbage, and other housekeeping chores. That night after supper, he distributed to us about four sheets of 15 minute quadrangles of the maps of the area, four contiguous maps. He reviewed those maps with us, only to the extent of writing some geographic names which were on the maps.
Doel:Had you already been working with maps at Chicago? You had familiarity with them?
Hubbert:Oh, sure. The geology course, the laboratory work was very largely topographic maps. Or to a considerable extent. What he did then was to supply place names, geographical names, of features on the various maps that were not on the map. Like Rattlesnake Gulch. And a few other names of that sort. But no information other than just that type of thing. We started out for our first field trip the next morning. We went up the railroad track, and here was this lake about a mile long and a half mile wide or so between cliffs, 500 feet high quartzite cliffs. We came to the first outcrop, and he started quizzing us about this rock.
Doel:There were only undergraduates with you on this trip?
Hubbert:Yes, we were all undergraduates. The total number in the course was 12, I believe. We divided up in teams, two men to each team, and we paralleled together for the whole trip. Here was a whole collection, making a one day reconnaissance around within easy walking distance of the camp.
Doel:Bretz was the only instructor, only professor present?
Hubbert:Yes. And he wasn't instructing, in the sense of telling us anything. He was quizzing. "What are you looking at? What do you see?" As I remarked, we finally, decided after some quizzing, it wasn't granite. It had bedding and that kind of thing, and it had the appearance of a sandstone, except it wasn't a sandstone either. In fact it was a consolidated sandstone and a quartzite, with very clear sedimentary features you could see. Then he said, "Now, if you were original investigators here, you would have the privilege of naming this formation, but since there have been people here before and they've already named it, we'll accept their name. It's called quartzite." But only after we'd established that it was quartzite. Well, we worked our way on through the flat bed by the lake, and in up the slope. There was a gentle slope on up to the crest of this ridge. Perhaps I should go back just a minute to say that on the topographic maps, you would see these topographic ridges very clearly. We were in the middle of one of them. They were several hundred feet higher than the more-or-less horizontal flat ridges. This particular ridge was nearly 500 feet above the surrounding plains. On the map then you could trace these. Here was this south range, as it was called, the Baraboo range. It was about 15 miles long and had a direction of about north 60 east or so, south 60 west. There's another range, the north range, which was nearly straight east of us. These two intercepted on the east end, where the south range went like this and the north range like this, [demonstrating with his hands] and they came to about a 30 degree intersection here. Say the south range would be the hypotenuse. The west range would be one of the angles of a right angle triangle, and the north range would be the other side. This whole thing formed a kind of a right angle triangle outcrop about a 30-60 triangle, approximately. We had this gap here with a lake in it, and no inlet, no outlet, just this lake standing here and the 500 foot cliffs on both sides. The North Range on the map showed two gaps. The Baraboo River came from the north, the little Baraboo River came through the westernmost gap and through this interior basin and went out the east gap. That flowed into the Wisconsin River, whatever river is there. The Wisconsin, I believe.
Doel:We can check on that.
Hubbert:OK. We went away then up to this crest. We could look down on the lake. Looking down toward the lake, there were pinnacles of quartzite standing up like pillars, just block on block type of thing. There were quite a few of these on this steep vertical cliff farther to the west.
Doel:You were on the crest looking down?
Hubbert:We were looking down. The question then was, with regard to what we were seeing: how did that lake get there and what was this gap doing? I remember, it's just a detail, but we all had in mind the glacier. Do you think there had been a glacier here? Well, of course, there was a glacier everywhere in that country. Looking at these pillars, do you think a glacier can be here and not knock those pillars over? Do you think that erosion since the glacier was here might have etched out these pillars? Obviously ridiculous, it couldn't be. There hadn't been any glacier. (Laughter) Yet in our discussion it was brought up that when we had dug this garbage pit the previous night, in the gap, we had came up with great big glacier-like boulder in there, in otherwise loose ground. It apparently was glacial drift we were digging in there.
Doel:How far away was this from where you were?
Hubbert:Not far. We were up on the ridge and the camp was down there in the valley, at the south end of the lake. Out of all this discussion it emerged that sure enough, there had been a glacier, but it hadn't been up here.
Doel:Was it a terminal moraine?
Hubbert:It had been down in the valley. But here was an area the glacier hadn't reached. Out of this emerged that there was a local area there that somehow or other the glacier just didn't get to. It came into this canyon from the north, established a terminal moraine, and came in from the south and established another terminal moraine. It left the lake there, but it didn't get up here. All right, that was the ground work. That was the principal, but not the only question. Another question was, how did that canyon get there? Well, we were dealing with, a region of paleozoic rocks. This quartzite was older. But we had fragments of the paleozoic rocks up on the shelf as we climbed up there.
Doel:So you were of course inspecting the rocks on the face as you were climbing.
Hubbert:Yes. What began to emerge was that this whole range must have been covered by paleozoic undisturbed rocks. We came to realize that the depth of this quartzite when we saw it was about something like 20 or 30 degrees to the northward or slightly northwestward, in the South Range. So how did that canyon get there? Well, it must have been cut by a river, and the only way it ever could get across this ridge was it had to start above the ridge and go down. Then when the glacier came and went over the edge, there was no more river; the drainage had all been disrupted. In fact, it had been dammed by the ice in both directions, actually discharging into this canyon. The only possible outlet with the ice damming the canyon at both ends was for it to flow over an outlet over there. It was lower than the other cliff on the other side.
Doel:How much did Bretz lead you to that conclusion? What role did his questions play?
Hubbert:Well, he played a vital role, but nevertheless things were handled in such a way that we had the primary reasoning, the primary evidence, and the conclusions. In other words, the conclusion was ours, in the light of the facts we were learning there. There was the deduction that if the glacier was on both ends here, water had to get out somewhere. The lowest place, the outlet, was across the cliff on the other side. You could go over there and look to see if there was any evidence of that. It was a productive type of analysis. That was the first day's work. Then every night after dinner we'd settle around in the big tent, and work on our notes, and maps if there was anything to put on them. Later on he would quiz, when we were settled down as teams. He'd quiz each individual team separately. What did they see that day? What did it mean? Our first day was that general reconnaissance. What we discovered was this glacial drift, this unglaciated area. Well, that immediately led then to where was the boundary between where the glacier came and where it hadn't been? It must have been a terminal moraine.
Hubbert:This was the first assignment the next day to these teams. Each team was given a separate section. Since there were about 16 sections to go, why, it took about six days for everybody to do all this. The teams were assigned the job of mapping in the field this terminal moraine. They just walked it out, back and forth, to see where the glacier had been and where it hadn't been. Then they got it on our map. It did some funny things. It came around; there's one place where it did a bow knot type of thing and on around. Again, at night, Bretz would take each team separately and go over their maps, say, "What did you see?" Well, if you were very confused, he might send you back to do it over again. But if you came up with something that was very accurate, then that would be that. Mapping this terminal moraine was the first assignment. It took altogether a few days because there were two parts to it, I guess. We did another part the second day. I don't just remember now. See, we'd have these assignments where the individual teams would work. Then, in between times, we'd do our reconnaissance trip where the whole group would be together, and block out another area. Then teams would be assigned to do the details.
Doel:And Bretz would go with you when you had the large group?
Hubbert:The big groups, yes. But the individuals, no. He'd just show us on the map where we were going to go, what our assignment was for that day. Then he'd go over it with each one of us at night, what we saw. I don't remember just the chronological sequence, but something that interested me very, very much was the deformation that occurred in this South Range. Here was this thing was about a mile thick — incidentally, of solid quartzite-dipping about 20 degrees I guess slightly northwest. There was one place there which I've seen described in textbooks subsequently. [Begins drawing diagram]
Doel:While you're making that diagram, let me just ask you; did Bretz take his classes back to the same locations when he made his annual field trips with his undergraduate students?
Hubbert:Oh yes. He'd been going to this area for this course, and he'd been giving it for oh, 20 or more years.
Hubbert:Going back again to the top of that ridge [refers to diagram]. The question was whether there'd been a stream that had come down here. Sure enough, there were potholes on top of this quartzite. They were hammered out by boulders and so on in a running stream, on what now has no stream whatever, just bare rock up on a high ridge. But the evidence was that there had been a rapid flowing stream running across this region, in terms of this erosion, these pot holes, and impact scars where boulders had hit and made circular structures. Another thing: he said that there had been found in the early days there some paleozoic fossils up there in the loose material, which were residual from rocks higher up. But the other thing that I was starting to mention was this kind of thing. Here was a —
Doel:You have a diagram now.
Hubbert:Yes. This is bedding. This had been clay rock or shale, but is now slate. This was quartzite.
Doel:And this is all exposed.
Hubbert:Oh yes. This would be on the cliff, vertical face. And what you have here was a vertical slaty cleavage. In the sketch here, I don't know if you can see it or not.
Doel:These diagonal bands across the slate?
Hubbert:Yes. And then there were fractures in the quartzite which were more nearly at right angles, but this made an angle of about 30 degrees or so to the bedding. Here's bedding going this way.
Hubbert:Well, look at the evidence again, this folding. The basin is to the left and the North Range is over to the north. The sheer motion in this folding would be like folding a telephone book. You'd have a slippage of this kind, in the bedding. Then you had this kind of a reaction in the more plastic material, and this fracture in the more brittle material. That was a very intriguing type of thing. It entered into my thinking over the next two or three years in various connections. Another thing observed on the other side of the lake was a place similar to this. I mean it was deformed, but this time it was quartzite. It was a layer of quartzite, oh, 8 inches thick, maybe. It was folded over in a thing like this. [Moving his hands] Here was this solid hard rock and yet it had been folded as if it were made out of putty. That was impressive. How this kind of thing could have happened?
Doel:Were other students as impressed, as taken by that, as you were?
Hubbert:I don't know.
Doel:Did you talk with them about it? Share your enthusiasm?
Hubbert:It was a long time ago. There wasn't very much technical discussion among the students, other than the individual teams. And again, on any particular problem, it was essentially non-discussable until everybody had done that work, and ultimately all agreed — or at least had done the work. Then they could discuss what it meant, and out of that would finally emerge the evidence. So and so must have happened. You could discuss freely, anything after the problem had been solved, or in the final stages after you'd had the observations. Then you could say, what does it mean? But no future problem was discussable until after you had done all the work.
Hubbert:It was as if you were the first man in the area. You were just describing these things and wondering what went on here. About the same time we were still working on the quartzite, we went over to the North Range. On that westernmost tip, there was an erosional pillar in that gap.
Doel:Was this one of the pillars you had observed before?
Hubbert:No. The first ones were in the canyon there by the Devil's Lake. We're now over on the North Range.
Hubbert:In the gap in the North Range, there was a pillar something like this. (Moves his hands) The bedding was essentially vertical. The pillar was 10 or 15 feet square, maybe 10 feet square and 20 feet high or so, just standing there, an erosional block of solid rock. But the bedding which you could plainly see was vertical. Here, in this sketch, we're looking west. Then what you have here is divided in two parts. One part is this solid quartzite. The other part is the more shaly material. You get the shaly kind of material and the fracture. The shear block is the north one.
Doel:As we're looking from the west.
Hubbert:This is west and this is east. We're looking westward. In terms of what we saw in this place over here, the inference is that your shear motion parallel to the bedding was like so.
Hubbert:If so, how does this add up? With your outcrop, and with the bedding over in the North Range vertical, then this is the same formation. You're coming down here and then you turn up like this. Here you're on the vertical side, the north side of this basin. The south side is the general tending dip, so that as it folded, this would be the kinematic response, the shearing response. There would be folding in this manner. Well, on this particular rock, there was a bronze placque erected by the students of the University of Wisconsin, calling this a Van Hise Rock. Van Hise had featured a photograph of that rock in his great treatise of 1896 on "Principles of Precambrian Geology," published by the United States Geological Survey in one of those big tomes. So this plaque was put on. Well now, the irony of it — and we didn't appreciate that at the time, for I discovered this particular aspect several years later—was that in that figure as Van Hise drew it, he had the shear motion wrong. He had the fractures right, but he misinterpreted it. He had top and bottom reversed. He had top to the north and bottom to the south. It would be the other way around, because in a basin like this bottom would be to the south, and top to the north. This was a good locality for examination of various criteria. Here's a rock sticking up vertical. Which is top? Which is bottom? It makes all the difference in the world in terms of interpretation of what you don't see. There was this mechanical thing, the fractures. The other is sedimentary structures, things like ripple marks. There was a quarry right nearby and there were good slabs of rock with ripple marks on the bedding face.
Doel:Bretz had taken you over to inspect that too?
Hubbert:Oh yes. There are two kinds of ripple marks: there's current ripple marks and there's oscillatory. These were principally of the latter kind. They have a cross-section which has large curvature in the trough and sharp in the crest. When you see these on a vertical slab, you can reach out, tell which is top which is bottom from the curvature of the bedding and the ripple marks. Some of these individual layers have sedimentary bedding that runs something like this. There's a deltoid type of thing, where the current is flowing in this direction. This was the leading edge of the sand, going down a little slope. The top part of that is truncated. The bottom part is more or less tangent to the bedding. You have these various criteria. There's still another one. Someone got a little layer, maybe an inch or so. There's a gradation, with coarse sand at the bottom, fine sand at the top. That gradation can help you infer top or bottom.
Doel:Had Bretz already investigated the Scablands in Oregon at that time?
Hubbert:Yes. He was in the midst of it at that time. He was working on it.
Doel:Was he particularly sensitive then to evidence of fast water motions, ripple effects and so on?
Hubbert:Well, you see, at that time, I didn't know anything about Scablands. After all, I was just an undergraduate student. All we knew was that he came in from the West where he had a more advanced field group, but what that was, we didn't know. We never heard of the Scablands at that time. But it was when he was working on it.
Hubbert:Yes. So we had all these criteria right there in the neighborhood in an adjoining quarry which had these same rocks. It all added up unequivocally that the top was to the south, bottom was to the north. That means that these rocks at this North Range went down and turned back and came up the other way. You have a continuity of outcrop around the West end, and also where the two come together at the east end. It's just a knoll of the same quartzite making a sharp right angle turn and coming back again. There's no question whatever on the basis of what we could see that this was a basin-like folding of these Precambrian rocks. This formation being about a mile thick, and that it was steeply folded to the north, more gently to the south. In the interior of this basin, there was an area of Paleozoic rocks overlying the quartzite. The quartzite was not visible. In those areas there's a mine shaft going down through the Paleozoic rocks. They were mining ore in a formation above the quartzite but all subsurface. That mine was not operated while we were there, but the buildings was still standing. Numerous samples of iron ore and other bags were put up on shelves. It hadn't been closed but a few years.
Doel:You hadn't gone into the shaft itself? You just looked around the buildings?
Hubbert:No. The mine was closed. No means of access. Inside there was some secondary things like visible faults in the Paleozoic sandstone, the limestones, inside with the displacement. There was also the polished rock where these two blocks had slid together and kind of glazed the surfaces, or as it's called, slickensider. Things of that sort. Then we made excursions to the north. A few miles north of there are again Paleozoic rocks. The Wisconsin River flowed through essentially vertical sided channels, through these rocks. In fact, it was a major tourist place. It's called the Dells of the Wisconsin. There were various boats there to take the tourists through these channels, and we did that, just as general background of the region. We saw these Paleozoic rocks again. All this altogether took about a month. I won't dwell on further details, but this was the way it was done. No question was discussable until we had the field evidence, and then the question came to, what does it mean? Out of it came essentially unique solutions. There just wasn't any other way, like glacial drift. Also the question of the overflow from the topography where did water go? We had the pond, and we found sure enough over there the old shorelines which were discernible. In that month's time, we had investigated this interesting region. It had rocks from the Precambrian, the late Precambrian up to the Pleistocene, the last 12, 15 thousand years. Oh yes, another question, was the question of this canyon. Almost certainly it was the pre-glacial Wisconsin River, and had been blocked by the glacier after the glacier went through. The river now swung around to the east of this ridge and on down, although originally it had made two of these canyons, one in the North Range and one in the South Range. But those had been blocked and the drainage had been disrupted. Finally at our last session, after we were winding up, Bretz said, "Now, we've found out quite a bit for this course, and it's completed. Why don't you write a report on it for another half credit?" All of us hated to write reports on anything, or written assignments in school. We were of the mentality that anything over five pages was a major task.
Doel:How many pages did Bretz have in mind for this paper?
Hubbert:He scared the hell out of us by showing us a typewritten report of earlier students that was roughly a half inch thick. [Laughs]
Doel:That's interesting. Did that include maps, or was that just the interpretive test?
Hubbert:Well, that was the typewritten text, but it did include maps. The principal thing was the text itself.
Hubbert:So if we cared to write a report on the area, we'd get another half a unit of credit. Well, the last thing I wanted to do was write a report, but I needed the credit. So I signed on to write my report. Various others probably did too, but I don't know if anybody did except myself for after this, it was all individual. But Bretz said, "All right, you've done the work, you've seen the evidence and you know what went on here, and fairly accurately. But there have been others in here ahead of us, and they wrote papers on this. When you write your report I want a complete bibliography of the earlier papers on this area. You are to read those first, before you start to write your own report."
Doel:How many papers were there?
Hubbert:Maybe ten or twelve. And they ranged all the way from very short papers of four or five pages up to a bulletin, published by the Wisconsin Geological Survey, I think.
Doel:Was this bibliography dominated by people from Wisconsin? Van Hise and his colleagues?
Hubbert:Well, I think somebody from the US Geological Survey wrote a report. I'm not quite sure. This particular report was written by a couple of people from Iowa. I just don't remember. The important thing was this frightening prospect of having to write a report, and being shown this typewritten report another student had written about that thick [holds fingers about an inch apart]. Now we came back, as the school opened. Maybe I should drag in here a thing that's irrelevant as far as the course is concerned. At the very end of the course, Bretz had been staying in and waterproofing the canvas on the tents. It was a very foolish form of waterproofing because it had paraffin dissolved in gasoline. He was painting these tents with this paraffin and gasoline, but the paraffin was flammable and we had small stoves in each tent. It was getting chilly, frosty weather, in September. About the next to the last night, I think, we were in the big tent, my tent, working on our notes. We had four people to a tent. This tent caught on fire and burned down. I and a number of people with me lost clothing, possessions, all except our notes which we had with us. In fact, I borrowed Bretz's compass, I didn't have one — it was a victim of the fire. So that terminated everything. We were actually planning another day's excursion, further south, but the trip was terminated by this unfortunate event. I didn't get to work on this report I guess until Christmas. School started about the first of October, and during the Christmas holidays I was working on the report. I started to read these reports in chronological order, and it came to me like a revelation. The oldest paper on the region was by Charles R. van Hise when he was a comparatively young man. He'd gone in there about 1870 or so, he'd taken a quick look around, and produced a report which he published. What he had in that paper was this. Here's the North Range. Here's the South Range. [Refers again to map]. And so what does he do? He considers these two as both parts of the rim of a huge anticline. The south end of it would be covered up somewhat by the Paleozoic rocks. See, what that does is reverse top and bottom on this North Range. Now the top, as we saw, was to the south. He has the top to the north. It makes a vast difference. Top and bottom question. I started to read this literature, and then I discovered the great Charles Van Hise had the whole thing upside down! [Laughs.]
Doel:Had you known of Van Hise's work by that time?
Hubbert:No. But out of this was emerging that he was an outstanding geologist. He was quite a young man when he wrote that first paper. Later on, he wrote the great PRINCIPLES OF PRECAMBRIAN GEOLOGY. He had that picture of this rock, which the students of Wisconsin later put a placque on. It was only several years later, studying that picture and his text, that I discovered he still had it upside down in the version that came out in 1896. [Laughs.]
Hubbert:And in that week he had a lot of criteria for determining top and bottom. So the students of the University of Wisconsin put a placque on one of Van Hise's major boners. Which is a kind of an irony. I read these things through afterwards. You see all the earlier papers, partly right and all of them seriously wrong. Then you run into something that has to be clarified, or you run into something that the first person didn't know about, and the picture emerges a little better. Then you get the third one, and you get a new addition to the picture. By the time you get through the whole works, why, the picture emerges more or less as we had drawn it. In other words, by being directed to key localities, we had done the amount of work that had taken the original men two or three years to do, just in these key places. You saw this gradual evolutions, partly right, partly wrong, sometimes seriously wrong, and incomplete. Then the later one add to it and correct the former errors and add a little here and a little there. By the time you're through, the picture emerges from the literature very much as we had concluded from our first-hand observations. That was a revelation of sorts. By this time we were all back at the university. Now there was one other thing Bretz did. If we just all went off writing our reports without any guidance, we'd come out with chaos. Bretz didn't want that. He said, "I'll give you an outline of the main topics that are to be discussed, and everybody will follow this outline. But you write the report." He gave us the bibliography and he gave us this outline, and we wrote the report. Well, what happened was, instead of this fear of a ten page thing, we found we knew so much we needed many times this space!
Hubbert:There also was a psychological thing of first importance. Here you are to write a report and you could back up everything in it from your own personal knowledge and observation. Yet you knew so much that you couldn't get it all in five or ten pages. It took 30 or 40 maybe, as well as the maps and some figures, and cross-sections. That course was one of the major intellectual experiences that I've ever had. It was that transition from it's so because the books said so, that type of thing, to where it was so because the evidence says so. The books may be frequently wrong. Several years ago, when I was out at Stanford, the local Geological Society was having a conference of a kind of philosophical nature, on geological work. I volunteered a paper on Bretz's Baraboo field course as an example of a superb scientific pedagogy. I'm not sure whether I ever wrote that up or not but I know I gave the paper at that meeting. It was never published, I know that.
Doel:Was Bretz unusual among the Chicago faculty in his pedagogical style?
Hubbert:Yes, he was. He was a different kind of personality. He was kind of a brisk person. But he was also intellectually exacting. On my first acquaintance with him, I met him just briefly when I decided to pick a major. He became my faculty advisor. He laid out the courses I'd have to take, including this Baraboo field course. It jolted me financially, because I was spending all my summers just getting enough money to pay the tuition for the next year, plus holding down jobs for meals and room. I had a job for part of the summer. I was a camp cook for an archeological field trip for the Milwaukee Museum, digging Indian mounds on the Fox River in Wisconsin. That job folded about midsummer, and my money ran out. Then I had to go on this Baraboo field course. Of course Bretz helped me out by my driving the station wagon there and back.
Doel:Right, you mentioned that.
Hubbert:But the fire was a disaster, because it burned up my other suit of clothes. [Laughs]. I got back to school, and somebody advised me to go see somebody in the administration, the president's office. I did, and they gave me a grant of $250.
Doel:That was a considerable sum then.
Hubbert:Yes, it got me by.
Doel:Do you have any idea how you were selected for this grant?
Hubbert:It was due to the plight I was in financially. And they dug up $250.
Doel:Based on need, rather than intellectual accomplishment?
Hubbert:Yes. My record was that of an advisory [probationary] student. This brings back a thing I forgot. I told you that I was just barely admitted to the school.
Doel:You had probational status.
Hubbert:Yes, I was on probation. Well, let me get my chronology straight here. The Baraboo field course was in September in 1925. That was my second summer in Chicago. The first one, I was running the service station. This trip followed my first full school year. See, the first time I went two thirds, the winter and spring quarters. This time I was on a full schedule. Incidentally I had a full year of physics, college physics, during this same year, 1924-25.
Doel:Before you went on the trip, yes.
Hubbert:Right. That also included the course in historical geology during that year, as well as German. Then we had the field course, and went back to Chicago. Oh — I had applied to the department in Chicago for the position of assistant, laboratory assistant or something, during the coming year.
Doel:For the physics laboratory?
Hubbert:No, this was geological. Although I was a joint major in geology and physics, my main base was geology. My faculty advisor was a geologist. So when we got back to Chicago, another boy in the field course came around. I ran into him in the hall somewhere. He said, "Have you seen the bulletin board?" I said, "No." "Well, go look." I did, and I found not only did I get the assistantship, but I was in charge of about three or four other people. [Laughs]
Doel:That's wonderful. I was in charge of the other assistants. The geology assistantship included the rocks and minerals laboratory for the study of rocks and minerals and later on topographical maps.
Doel:That's quite an achievement.
Hubbert:They had about, I forget, two or three or four other students because there were various sections going on.
Doel:Had Bretz helped you in getting this position?
Hubbert:Oh, he was responsible. He did it. [Laughs] The whole thing happened on that field trip by getting acquainted with him. He was there with his family. He had two small children, a boy about nine or so and a daughter about maybe five or six. In conversation, it gradually began to emerge the fact that psychologically he'd been through very much the same kind of thing that I grew up with. He'd been to a strict fundamentalist Baptist college, as I learned later. He'd even, in the naivete of his undergraduate days, signed on to become a missionary.
Hubbert:This was the kind of background that he had to fight his way out of. He did it by lifting himself by his own bootstraps. We'd had very similar backgrounds in terms of that kind of thing. Also, I had just discovered or been introduced to a very remarkable magazine, H. L. Mencken's American Mercury. Are you acquainted with the American Mercury?
Hubbert:It was great. The person who introduced me to that was this man Frank Melton who had taught the first course in geology that I took in spring of 1924. He and I became very friendly after that. That was at the end of his graduate work. But he was working on a study of a major problem of the time, that pertained to the theory of isostasy.
Doel:He was working on this already while you were an undergraduate?
Hubbert:Yes, among other things. He did his doctorate on a field job out in Colorado. That he was principally interested in really was this isostasy problem. There was a whole series of volumes put out by the Coast and Geodetic Survey on gravity surveys. Those were the most authoritative sources up to that date, and he was working on that. I remember that first summer, 1924, somewhere along the line, he had me helping him. He was doing a lot of gravity tabulations and calculations, and he had me helping him on some of it. This was a routine type of thing, reading tables and that kind of business.
Doel:You'd gotten to know him fairly well that first year?
Hubbert:Yes, he and I had become very good friends, just out of that first course. It was he who introduced me to H. L. Mencken's American Mercury.
Doel:This was something you discussed with him?
Hubbert:Oh yes. I mentioned this thing to Bretz, and I think he went into it at the same time. Back in school then I'd been through a year of college physics.
Doel:Was there anything in particular you recall about those physics courses?
Hubbert:Yes, I recall them very vividly. The physics department had a full year of college physics, beginning physics, pre-calculus. When calculus was used, you developed it from first principle for that particular problem. Delta, so on and so on and so on; you add them up. Anyhow, that was equally revolutionary. I had a deep interest in physics from the time I was a kid. Mechanics and later electricity and so on. But no formal knowledge. Here was a system I could work out. First quarter was mechanics, second quarter was heat, and sound, I believe. Heat maybe, light and sound. Then the third quarter may have been electricity. I may be reversing those last two. But again, the mode of approach, everything about it was unfamiliar. There were two or three sections of this physics course taught by different instructors in parallel. Then once a week, there was a lecture for the collective group given by one of the most senior professors, a guy by the name of Harvey Lemon. He'd been working for years on this. It was a demonstration type course where you do experiments with a group, and also presented the basic theory of each experiment. Well, that demonstration series of demonstrations, lectures, and experiments you did yourself, was very, very enlightening. But the other part, the main course, this five hour a week course, consisted primarily of lectures and problems. I felt like a lost dog, because we didn't have a textbook. I'd never had courses where you didn't have a textbook that you could rely on, going back to high school. This man was just putting stuff on the board, out of his own notes. I remember mildly complaining to him once: couldn't I have a textbook that I could study on the side? He said there isn't any textbook. I looked a little startled. He said, "We write the textbooks." [Laughs] He did! His notes were his own, first from scratch. There really wasn't any good textbook at that time. Of course, they had one that was a kind of a background thing. It was really a second order-of-quality book. That's the only thing we had and, as far as I was concerned, practically useless.
Doel:Do you recall what that one was, by chance?
Hubbert:Somebody by the name of Stewart at the University of Ottawa, as I remember. Although we had it as a kind of a so-called text, it wasn't followed in the lectures. Its content was so weak and watered down that it was practically useless. Anyhow, after I got over the jolt of no textbook, I had to really knuckle down and work this thing out in first principle. It was a very major intellectual experience all by itself. In fact, I became very fond of this guy who was teaching the course. His name was George K. Morse. He had been an architect. I think he'd studied at the Beaux Arts in Paris and he apparently had a good knowledge of French. In fact, I still say "centimeter" ("santameter") because that's how he pronounced it, the French pronunciation. His own references were to the original French pioneer writers on particular subjects. He emphasized the importance there might be many, many things written on subjects, but if you knew the fundamentals of it you didn't have to bother with the rest of it. One that he cited was a book that I found in the second-hand bookstore later. It was published by Cambridge University Press. I'm trying to remember both the name of the book and the other. But it was Cox's. Cox was a man at McGill, I believe. I don't recall the title, but it was a review of mechanics. It was modeled somewhat after Mach's — I was going to say Max Planck…
Hubbert:Yes. He wrote a great book. It's still a great book, called MECHANICS. I don't know whether you know it or not. It's tremendous. It's elementary but it's fundamental, it's probing the foundations. It's worth anybody's reading right now.
Doel:It's a classic.
Hubbert:Oh yes. And it's still a fine book, and it was written in the 1890's. Anyhow, this Cox's Mechanics, that was published by Cambridge University Press. He had mentioned in his preface that it was modeled after Mach's book on Mechanics, maybe a translation. It took individual topics and developed them either by direct quotation or by the same method used by the original investigators.
Doel:Did he share the same philosophy as Mach?
Hubbert:Right. For example, in it he has something right out of Newton's PRINCIPIA. He has this proof that the attraction of a hollow sphere to an exterior point is the same as if the mass of the spherical shell is located at the center. But for a mass placed inside the shell, the attraction between the two bodies is precisely zero. This was taken right out of Newton's Principia. In fact, I think it was a verbatim translation. Then there was the pendulum, very important as a means of measuring gravity. He develops that, going back to a Dutchman, who developed the pendulum theory, and then Kater and the British, who developed the reversible pendulum. The theory of it is developed here. Then the impact between moving bodies, conservation of momentum, kinetic energy, and all that kind of thing is beautifully developed. Well, this man Morse recommended this to me as something worth taking a look at. I didn't have a copy till I found one at the bookstore a year or two later maybe.
Doel:Do you recall what other books Morse may have recommended for you to read? Did he also recommend any French physicists?
Hubbert:That's the only one I remember specifically, but I remember the cross-scattering. I always read the fundamentals before anything else. He cited this as a compendium of the historical fundamentals, that it was the historical development of the subject. And it was. This whole course, all three quarters of it, is the whole spectrum of the whole field of physics, and beautifully done. Of course at that time Chicago had perhaps the grandest physics department in the country. Or certainly one of them. It had Michelson, the first [American] Nobel Prize. He was a founder of the department. Millikan, the second Nobel Prize winner, was also a principal.
Doel:Of course Millikan had already left by the time you were at Chicago.
Hubbert:He left only about two years before. He left about 1923 I think, and I was in this in the fall of 1924. He'd only been gone about two or three years, I think. In fact the apparatus that we used was Millikan-designed apparatus.
Doel:In the laboratory, you mean?
Hubbert:Yes, the laboratory apparatus. Much of it was built commercially, but Millikan had designed it. So out of this, after I kind of got the swing of things — of course at first it was all very confusing-but after I got the swing of things, the way the whole thing was put together, it was just marvelous. And so in physics I even debated about doing graduate work under this man. He was trying to build up a field of crystals, X-ray crystallography.
Doel:This is Morse, you mean?
Hubbert:Morse. Well, actually he was kind of an outsider in the department. There as a lot of interdepartmental jealousy going on. It finally got so bad that the man a year or two later left in disgust. Anyhow, for the purposes I had in mind, general physics, it was a marvelous job that he did with it.
Doel:Can you tell me a little more about the controversy, the problems that Morse had? What was the nature of the disagreement?
Hubbert:Well, he came in as a mature man from the outside, and he'd grown up as an architect. As I say he went to the Beaux Arts in Paris, and he'd been one of the architects I think on the Wrigley Building. That was one of the leading skyscrapers at that time in Chicago.
Doel:Oh, that's interesting.
Hubbert:But he had this deep interest in science. First he wanted to go into chemistry. But he also was more or less a chain smoker, and the chemistry department had strict rules against smoking in the department, wooden floors and combustible chemicals. So he switched over to physics. He was in very good standing with the head of the physics department, who was also the dean of the graduate school.
Doel:Who was that at that time?
Hubbert:Gale. But there were other people in there that tended to resent him being there. It was a bad situation. So he finally got fed up and said the hell with it and left after a couple of years.
Doel:How well did you get to know Morse during the time that you were an undergraduate? Would you see him at times in the evening?
Hubbert:Oh yes, I knew him pretty well. Not intimately. Because he wasn't inclined to intimacy. But he wasn't formidable either. We were very good friends.
Doel:Would you see each other socially outside of the classroom?
Hubbert:Not really. I didn't socialize outside. I was working. At that time, I could tell you what I would be doing next week, Wednesday, at 3 o'clock. Or 6 o'clock. My days were frozen from early morning till bed time. There was no time for socializing on the outside. Well, let me pursue this item about the probation. It must have been early, I think it was early in the year 1925-26. By this time I was oh, a beginning Junior in this state I was in. Yet I did have this commitment that they would reconsider my previous courses if I didn't flunk out. And I hadn't flunked out. I'd become friends with one of the undergraduate deans who was a very influential person on the campus.
Doel:Who was this?
Hubbert:T. V. Smith. Thomas Vernon Smith. So I went to him and told him this story. He promised to review my credentials. He acted as my lawyer and went over arranging an appointment with the registrar who was an old lady about 60 years old, whose favorite activity was pouring over these things, credits. [Laughs] He broke the ice and made the appointment and I went over to see her. She had my records spread out, and we started to go over them inch by inch. She was looking over my high school credits. "Now," she said, "here's this credit in agriculture." I told you about that.
Hubbert:She said, "You know, these small schools, they just don't have adequate laboratories." I looked at her and I said, "Look. I was raised on a farm. I displaced a farmhand from the age of ten, working with plows and horses and so on. I worked on the farm all summer, before school and after school. Do you mean to tell me Chicago students have that much laboratory in agriculture? In the big Chicago high schools?" She had to admit she was licked and allowed the credit.
Hubbert:When we got through with this thing, I found myself a senior approaching graduation. In fact I graduated in the class of 1926.
Doel:That's right. You were done in June of 1926?
Hubbert:Yes, I graduated in June, 1926, with honors.
Doel:Which honors had you gotten, specifically? We should get that on the record.
Hubbert:I don't remember. I was one of the honors students in the graduation.
Hubbert:It was just a distinction that was made between those with and without. Citation.
Doel:We haven't talked about your senior year yet, and the courses that you were taking.
Hubbert:Well, let me look around a bit. See, I was running the two in parallel, the geology and physics. And mathematics. I was taking mathematics, but that was just incidental to the fact that it was a minor and I needed the mathematics for the other work. My interest in mathematics was purely in the applied sense rather than primary in mathematical theory. I had this year of physics in 1924-25. I then continued in physics. I had kinetic theory of gases and the beginnings of thermodynamics in the second year. I think I had a course on x-ray crystal analysis.
Doel:That would have been with Morse?
Hubbert:Later on I had a course in theoretical mechanics.
Doel:Was this when you were a graduate student?
Hubbert:I'm trying to think. I think maybe it was later. When I was a graduate, yes, because I went to see Professor Duncan McMillan who was technically a member of the astronomical department, but he taught these courses in theoretical physics. He was then writing a textbook in several volumes just at that time. Volume 1 had just come out, which was mechanics of the particle, volume 2 was mechanics of solid bodies, and volume 3 was Newtonian — theory of Newtonian potential.
Doel:Was this while you were a graduate student?
Hubbert:Volume 1 had just come out. I went to see him. I hadn't had his course. I knew about it. But I went to see him because I was going away for the summer, and that was something I might be reading on mechanics. He showed me the galley proofs of his book that he'd just written, volume 1. It came out shortly after and I bought it. I have it on the shelf over here still. I took the course after I got back, my first year graduate work, from him. That really was the principal work on physics that I had, along with the year of college physics, the course on kinetic theory, the beginnings of thermodynamics, and maybe two courses on X-ray analysis of crystals. In going back over to geology, coming back to 1925-26 —
Doel:Your last year as an undergraduate?
Hubbert:Yes. That year I took a course in geology that was fundamental at Chicago. I've never seen anything like it anywhere else. It had an entire year on an advanced undergraduate and graduate level in general geology, the whole scope.
Doel:And this was taken by both undergraduates and graduate students?
Hubbert:Well, undergraduates would take it if they were majoring in geology. Incoming graduate students had to take it. It was a required introduction. Now later on, after World War II, I met a Jewish student who had been to Chicago and he'd been in Israel. In fact, he spent a year with the Bedouins somewhere or other. He finally got to this country, and he told me this story. He had a Ph.D. from a German university in geology. But here he was a stranger in this country, he wanted academic connections, and so he went to the University of Chicago and talked to somebody there, maybe Bretz. He wanted to take a few courses and get oriented to American geology. I'm sure it must have been Bretz who told him he'd have to take this one year course. Well, he more or less protested. After all, he had a Ph.D. in geology from a German university. All he wanted was just some background on American geology. He was told very firmly that everybody who registered in the department as a graduate student had to take this course. Heinz Lowenstam told me it was the greatest revolution in his life!
Doel:This was Heinz Lowenstam?
Doel:I see. That's interesting.
Hubbert:He said he'd never had any experience like it. He didn't know what geology was all about till he took that course. In fact, he invited Bretz out to Caltech to give a series of lectures out there.
Doel:This is interesting. Who were the instructors for that class? Did one person teach it all year?
Hubbert:No, two, Bretz and Chamberlin.
Hubbert:Right. The first course was on again contemporary processes.
Doel:Right. This was the Bretz course?
Hubbert:That was Bretz. I took the course as a senior undergraduate. There were some things in the course that were the same as the elementary course. But the difference between this course and the elementary one was principally a critical examination of the various subjects, with also a selected general reading list. He posted on the board right at the beginning of the course a series of about a dozen references. We were to read those. Later on, the next day, he had another list.
Doel:Were these lists on particular topics in geology?
Hubbert:Yes. They would refer to this particular aspect of the subject that was under discussion. When we went into a new phase, there would be a new list.
Doel:Arranged by geological processes?
Hubbert:Well, this particular course, was about geological processes. Different aspects of that. But the important thing was this reading of the literature. Before with literature as we'd been brought up in high school, authors were just an abstract "they". Here all of a sudden they became living people, human beings, fallible human beings. These selected readings, were by people like William Morse, many others. But there were people we'd never heard of before. Here were the top people we were studying and here's what they'd written on it. So that was important. In the class, incidentally Bretz did not lecture in the conventional sense. He largely probed and asked questions.
Doel:He kept asking questions?
Hubbert:Yes. He was a challenge. And again, intellectually… divided the students. There were certain students who just didn't mentally fit into this scheme of things. Others just ate it up. But well, to give you one specific thing that I remember. I guess in this course we got around to the question of how large a boulder a stream could move. A small stream maybe could move sand grains. You get a little bigger and you could handle pebbles. Then you had extreme cases where they could move great big rocks. And what was involved in that? Well, on the physical side, you would try to go into some physical variables. Bretz was not a physical scientist, but he had some provocative questions concerning it. Well, related to that, in the second course after this we went into historical geology. Rollin Chamberlin taught the course on Precambrian geology and generally up to the end of the Paleozoic. That was the second course.
Doel:Did he teach a particular theory of origins, his father's?
Hubbert:He was very much imbued with his father's hypothesis of planetary origins. It was indeed one of the major theories in development in earth science at that time. But Rollin Chamberlin's weakness was that he was worshipful of his father. He couldn't possibly be critical. He wasn't capable of being critical. Whatever his father said was it. And that was his serious weakness. So that when he was discussing planetary formation hypothesis, why, he'd be talking about the arguments that Chamberlin had gone through about the distribution of the energy among the planets. The momentum and what-not. I remember one time when he read off the arguments verbatim. But when you asked him what momentum was, he didn't precisely know.
Doel:That's an interesting point.
Hubbert:He was mouthing words he didn't understand.
Doel:Do you recall other discussions with him?
Hubbert:Oh yes, I had many.
Doel:Were any especially memorable during that undergraduate year?
Hubbert:Well, I guess it was in parallel with this, I also took his course in structural geology.
Doel:This was also offered in the senior year, your senior year?
Hubbert:I think it was. Maybe I'm wrong. Maybe I didn't take that until the first year of graduate work. I guess so. Anyhow, Rollin was also heavily involved in this Wisconsin ancestor… The University of Chicago geology department came largely out of Wisconsin. Thomas C. Chamberlin was president of the University of Wisconsin. He took that job. He brought R. D. Salisbury with him. And then he had visiting professors. He had Charles Van Hise, C. K. Leith, coming in as visiting professors.
Doel:That's interesting. That was before the time that you were there though, at least Van Hise? Also for Leith?
Hubbert:Oh yes. This was in the very early stages, 1890 up to 1910 or so. And so there was a very strong Wisconsin background running through. All these people were very much interested in glaciation because the whole state of Wisconsin was heavily involved in glaciation. Well, this is what got Chamberlin, T. C. Chamberlin, into this origin of the earth question. Prior to that time, the earth had been a molten body, and it was cooling off, and it had a thin crust. As it shrunk it wrinkled up and made mountains, and eventually it would just freeze. The Ice Age and the glaciation was kind of the terminal approach to this cooling off.
Doel:An evolutionary scheme.
Hubbert:Yes. Chamberlin even brought up the Wisconsin evidence of glaciation, and then began to report that they had glaciation in the Caribbean and Australia, for example, and every place else. We had some Precambrian evidences in Scandinavia. That just didn't fit into this scheme of a cooling-off earth. Well, our German graduate went back to look at one or more premises of where did these ideas originated, where did they come from? And it went back to Laplace on one side, and one of the German philosophers — only I don't remember which one-who had formulated that a gaseous body finally congealed to a liquid and then gradually formed a crust and all the rest of it. It was the standard orthodox picture of the earth. And the more Chamberlin looked at it, the more this wouldn't hold water. That led him and this very profound inquiry as to what could have, how the earth could have happened. What he arrived at was that instead of it being gas condensing down, it had been a conglomeration to a great extent of meteorites. In that case, if you shrink a gaseous body, you increase the temperature with the shrinkage. In case you're impacted by meteorites, the heat generated is dissipated by an outer radiation.
Doel:Right, plus it's a local impact.
Hubbert:Yes. Well, Helmholtz was one of the German authors of this heat generated by the convection and friction. Well, anyhow, then he got Moulton in with him on the astronomical parts of this thing. They worked up this theory of the near approach of two stars disrupting each other by tidal forces, and scattering the debris around, which was largely in the form of meteorites and fragments of that kind. Some of them became planets and some of them accumulated into the earth. This gave a totally different history, thermal history, than the one we had before. Chamberlin had also raised the question clear back in 1898 of the possibility of there being energy inside the atom. Lord Kelvin published in Science in 1898, a paper on the origin of the earth, I think as an abode for man. He summarized this last work on that subject, almost. He finally concluded that the earth had cooled off enough that it could support life only about 20 million years ago. It was an elaborate statement with refinements of things he'd been writing about since the 1860s.
Doel:Right, and all before the discovery of radioactivity.
Hubbert:Chamberlin replied to that in Science. I never heard of this reply till I got it from Professor McMillan, astronomer. And he said that Chamberlin just completely devastated Kelvin. I read it on the basis of that recommendation, and I think he did. But in one place, he raised the question as to what evidence do we have that there might not be energy inside the atom? And perhaps the planetary system. And how sure we could be that it wasn't the case? The energy generated by atoms inside the earth under pressure conditions that existed could account for these enormous sources of energy which the contraction hypothesis was not sufficient to account for.
Doel:That is, not sufficient to give a long time scale for the earth.
Hubbert:So in one single paragraph, which I've quoted in papers a few years ago, he raised this question about the possibility of there being maybe a planetary structure (of atoms) and processes going on inside the stars. We didn't know what might be happening. In that one paragraph, he conceptually anticipated the transmutation of the elements for the generation of the heat from atoms—Bohr in 1912—and this notion of it being the energy from the center-Bethe 1937 or so, '38.
Doel:Right, 1939 in fact.
Hubbert:'39, OK. But in one single passage of that paper in 1898, when the Roentgen rays had been discovered only two years or three years before, that was the only radioactivity evidence he had. That heat was generated by radioactivity wasn't until 1905 or so, and then the radioactive disintegration theory about that same date. And then the planetary atom of Bohr, 1912, I believe, and finally Bethe. The whole thing was confirmation of the speculative questions that he asked in 1898.
Doel:It was a remarkable paper that way.
Doel:This is a very interesting point that you're raising. It's before the time you were in school, either as a graduate or undergraduate, but did you have the feeling that the very restricted number of years Kelvin gave for the earth was a major problem for geologists? Or did they not pay that much attention to what Kelvin said?
Hubbert:Well, what happened was, Kelvin was such an authority in his day that many British geologists accepted Kelvin's conclusion and then tried to adjust geology to make it fit.
Doel:Did it affect the Americans the same way?
Hubbert:Well, it was in the air, in geological circles. Certainly in Britain there were quite a few British geologists who were rephrasing geological history to fit to Kelvin, even though Kelvin himself kept changing his figures, as time went on, in general shortening them. But by way of a contrast to that you have Darwin and his Origin of the Species. One of the chapters had Darwin's theory of length of geologic time and that was based on the stratigraphy of Great Britain. How much time would it take to form so and so much limestone.
Hubbert:Out of all this, Darwin came out with figures which were remarkably close to present radioactive time, based purely on the stratigraphy of Britain as it was known at that time. But in this chapter, Darwin has a passage which I probably can quote only imperfectly, to this general effect: anybody who can read Sir Charles Lyell's great treatise on the principles of geology and not be impressed by the immensity of geologic time may close that book.
Doel:Yes. Succinctly stated.
Hubbert:So, Chamberlin in this rejoinder that I referred to said that in the past, the geologists had erred somewhat in the matter of abbreviated time and others had accepted this shorter period, but he thought the majority of them were in neither camp or in-between. This was in 1898, as of that time. Then he went ahead. He said that although he was only a — he didn't say an amateur physicist, but he used a term comparable to that — he proposed to reply or to discuss Kelvin's thesis in terms of its physics, and he took it apart.
Hubbert:Well, that's background that I didn't even know at the time. I only read it much later. But what Chamberlin accomplished was the abolishment of all the preceding notions of the origin and history of the earth, and he brought the physical knowledge into compatibility with the geological knowledge on all this conflict between the cooling earth and so on. So whatever views we may have now, with enormously greater knowledge and data and considerations have been given during the last few decades, — I haven't followed this, I don't even know what the relevant figures, years are. Anyway, Chamberlin was the one who broke the ice.
Doel:Did Rollin Chamberlin take on his father's ideas in all areas of geology, not only the origin?
Hubbert:Essentially. Whatever his father said was sacred. It was a very significant weakness on his part. Now you raised the question whether I had discussions or perhaps disagreed with Rollin Chamberlin — yes. In maybe the same course, the broad course, see, I'd just been back at that time from Baraboo where I'd seen these rock deformations.
Doel:Was Chamberlin's course the first of the two part series?
Hubbert:No, the second.
Hubbert:What I'm trying to get at, trying to remember, is how this thing came in.
Doel:You would have just been writing the paper over Christmas.
Hubbert:I know the first time, I hadn't had his course in structural geology, which I took the next year. But somewhere in this year, 1925-26-it must have been in that broad general course that this thing came up. This question of these types of structures that was just stretching out here of the shear. Well, it turned out that Rollin Chamberlin had two textbooks or rather two editions of a textbook on structural geology. The first one was published I believe about 1912 or so and the other one was a revision published around 1923. Now, in both of these, Leith —
Doel:He was still at Wisconsin at that time?
Hubbert:Yes. Well, if we back up a minute, Charles van Hise wrote this Principles of Precambrian Geology. He got one of his colleagues in engineering at Wisconsin by the name of L. M. Hoskins, mechanical engineering, to write a companion paper on the mechanics of solid bodies. I don't remember what it was called; it had to do with finite strain and so on. That was a very able paper, published in parallel with Van Hise's first paper, and at Van Hise's instigation. What L. M. Hoskins did was discuss in a general way the theory of finite strain, and how homogeneous finite strain could be transformed into an ellipsoid of strain. And then he goes into some of the kinematics of that process, and he also takes up experimental results of tests that had been made on cast iron, for example. I don't remember what it was but I remember there was cast iron, under compression, and the sheer fracture was at about 30 degrees to the greatest principal stress. And finally it was less than 45 degrees, and as I remember, somewhere nearer 30. Now, this model that Leith used in his textbook I understand was a model by Mead, W. N. Mead.
Doel:Who was also at Wisconsin.
Hubbert:Yes. And Mead was a civil engineer by original training. But anyhow, this model involved a wooden frame of equal area hinged at the corners. And in the middle was a cardboard circular disk. This was an ordinary screen door, wire, with the mesh parallel to the sides. If you deform this, you can only deform it one way. That is into a parallelogram.
Doel:You would see the stress pattern reflected in the material?
Hubbert:Yes, but if you had a circle painted on the screen in the undistorted position, then when you distorted it, that circle went into an ellipse with the long axis parallel to the diagonal. You still had the original circle for reference. So the hocus pocus with regard to this was, he came right out of maybe Leith's textbook and he had the question of rotational versus irrotational deformation, or stress, as I believe he referred to it. So he did two things with this. You could put it on the table diagonally and press down on it, and the strain ellipse was right angles to the compression. So that was irrotational stress and strain. The other way was that you laid it with one side flat on the table, and you distorted it like that. Then your ellipse was like so.
Hubbert:And that particular ellipse rotated, its axis rotated as you progressed. He showed it around to people.
Doel:Chamberlin had gotten one of the models?
Hubbert:Chamberlin had one. Chamberlin did this hocus pocus of pushing these things down one way, perpendicular to the greatest stress, and then you had this other, with the shear stress, and the other strain was oblique to it. If you didn't see it happen, well, what you've got is the frame and you can't tell the difference. And the first time this was mentioned was in this course; it was just brought in I think obliquely. He said it was all based on thermodynamic principles. That was important enough, I thought it was important enough to ask, what were they? Well, he was a little bit nonplussed—said it would all be explained in detail in a more advanced course, his course in structural geology. What impressed me with the thing was that it was entirely erroneous because in that second case, they would have been kidding themselves if they were applying only one force. The total torque applied on this thing had to be zero or it would spin. And so all right, if it didn't accelerate angularly, the total number of total torque, had to be zero in all cases. Anyhow, that pertained to these things here. Because you had that situation like here, and you had the stress like so, and the one bedding where, you're supposed to have these two in this wire model, you have the measures going this way and this way, and so they were cutting this circle in these two patterns, and there was stated to be the positions in which a fracture would be most likely to occur. But these two fractures had their obtuse angle toward the diagonal, which in this case was the greatest compression. That was entirely contrary to the experimental evidence on cast iron and so on cited by L. M. Hoskins, although Hoskins had apparently been the inspiration for this model. But it was a misinterpretation. Well, anyhow —
Doel:Just to be certain, you were first acquainted with that during your senior year when you had taken this course? It wasn't in the structural geology course?
Hubbert:No. I didn't take structural geology I guess till the next year.
Hubbert:Anyhow, when we got to structural geology, he did exactly the same thing and said exactly the same thing. It was all based on thermodynamic principles. I came back again, I still want to know what they were. Well, we got into a great hassle over that. In fact, there almost ill feeling between us. I finally decided that I couldn't talk with him, and I thought the matter was of great importance in terms of understanding these field phenomena. So I went to work on it privately. I had a room down in the basement, at least a place in the basement that I could get to.
Hubbert:Of the geology building. And so I devised the following experiment. I took, I suppose, a 2 x 6 board, and sawed it diagonally. Then I separated the two parts. Here, in the gap I placed — what do they call it? Pleistocene, I guess, modeling clay that artists use. I filled it in here. Then I made a gridwork of threads embedded in the surface for reference, and I stamped with about a one inch diameter rod of some kind, imprinted. So then pressing on this and the end, I had a circle(?) on it, one like this and like this, (demonstrates with his hands). These things sheared into three ellipses. I worked out the mathematical theory of that, and it matched. One of the things that was wrong in the paper as it was written was that I, instead of dealing with stress analysis, dealt with force analysis. I had a total force, a shear component of force, so it wasn't stress on the area. It involved force on the area, which I didn't have. Aside from that, the physics was correct.
Doel:Right. These are the first two scientific papers you published that we're talking about?
Hubbert:The second one. So I finally gave this paper. I'd been doing it entirely on my own because it seemed to me futile to try to discuss it any further. I carried out this thing, simple experiment, and I gave it to a meeting of the Geological Club of the department. Chamberlin was there.
Doel:This was a seminar?
Hubbert:Well, this little club had its own affairs, but it was a Geology Club.
Doel:Did only people from the university attend?
Hubbert:Yes. It was just a departmental thing.
Doel:Undergraduates and graduates?
Hubbert:Yes, mostly graduates.
Hubbert:So I gave this paper. Chamberlin was kind of giving me hell because a loud mouthed graduate student had been sounding off to him over what I was doing, implying that I was going to knock the props out from under him or something or other. He'd gotten pretty — in fact, he called me in, kind of dressed me down a little bit over this second-hand misinformation. And so I gave this paper in our club, on the mathematical theory I'd developed. Chamberlin was there, and he was tremendously surprised. He apologized to me. One thing that came up, I hadn't allowed for the compression, narrowing of this thing. Some of the people pointed that out — the deficiency — and I said, well, I thought I could handle that, and I did. I wrote that into it also. And the whole thing fit together. Eventually, I wrote up a publication and Chamberlin published it in the Journal of Geology. Not only that, I got my master's out of it.
Doel:That was your master's?
Hubbert:Yes. It wasn't written as a master's, just as a published paper, but they gave me master's degree for it later on. One of the reasons that I was even interested in a master's degree was that Frank Melton was promoting me for a job in Oklahoma, at the University of Oklahoma.
Doel:He had left to go there in your senior year?
Hubbert:Frank Melton left Chicago in that summer. Well, he was doing field work, maybe, that summer. But the following year he went to Columbia, in what capacity I don't know, but I know he didn't like it there.
Doel:Had he already finished his Ph.D.?
Hubbert:Yes. But he disliked Columbia. He was only there a year or two, and took a job at the University of Oklahoma.
Doel:I want to talk to you more about what happened at Columbia and the papers that you published. But before we get fully into your graduate career, I was curious if you had thought at all about attending any other graduate school in geology, as you approached your senior year? Had you talked to —
Hubbert:Well, when I graduated from Chicago, why, of course the question was wide open as to whether I would continue at Chicago or go somewhere else.
Hubbert:Just at that time, Caltech was establishing their geology department, and I was interested in that. I wrote a letter to Buwalda as the chairman of the department inquiring about a fellowship. I'd heard they had fellowships. I never heard from him.
Hubbert:Finally, about the end of the summer, I got an apologetic letter from him; he'd been out in the John Bear Basin on his summer's field work and he didn't get my letter until weeks and months later. By that time, it was water over the dam.
Doel:Do you think you would have gone to California, had they come through?
Hubbert:Had they offered me a fellowship, I would have gone.
Doel:How much did you know about the people who were there?
Hubbert:I knew very little. I knew not very much, because Caltech was a very new institution at the time. What I did know was that the faculty were offering fellowships in geology and I applied for one. The letter got lost or buried and never arrived, till months later. So the books were closed by the time he got it.
Doel:Had you also thought of other universities?
Hubbert:Not particularly. When I graduated, I had my first oil job that summer.
Doel:Right, that was the summer you were at the Amerada Petroleum?
Hubbert:Amerada Petroleum Corporation. Mostly in the big, what was then called the Almoretto Field, what they call the Pinell field. There were about 500 drilling wells. It was probably the biggest oil field in the country at the time, or one of the biggest.
Doel:How did you get that job?
Hubbert:Chicago did not have a course in oil geology, so they had an arrangement that they occasionally invited in oil geologists to come in and give a special course in oil geology. In the spring of 1926 they had a man by the name of Fred B. Plummer from Texas come up. And also an associate of his, Don Barton. The two of them together put on this course in oil geology and geophysics. I didn't take the course, but Don also taught a course in planetable surveying. I took that. He was apparently so pleased with what I'd done in that course that he offered me a job with the Amerada in Texas, I had that summer's job 1926. Then I came back to Chicago for a year of graduate work. At the end of that year, I decided to take a year off and I went back to Amerada for a year, actually 15 months, a year and a summer. I needed a little change, a breath of fresh air and some cash. I took this year off and worked for the Amerada. After several months, six months or so, I had three months of field geology, and I got transferred over to a pioneer seismic group.
Hubbert:Doing seismology in 1927.
Doel:Still with the corporation?
Hubbert:They had a subsidiary called Geophysical Research Corporation. The seismic work was done under this subsidiary. I was working for Amerada, but I was transferred over to this experimental seismic group in West Texas.
Doel:Was that primarily because you had more background in physics than most others?
Hubbert:I really don't know. It's probably the fact that I'd been on this training party, geological party. It became obvious that I knew a little more than some of these other guys did. This crew was coming through. In fact, they needed a surveyor. I was signed on as their surveyor. I went to that job then for a year. Actually I was on about three different crews, from one to the other. Then I signed off and went back to Chicago in the fall of '28. Yes, fall of 1928.
Doel:You always expected to go back to Chicago?
Hubbert:Oh yes. I was offered a permanent job when I was out there, but I turned it down.
Doel:Was it nevertheless tempting at the time?
Hubbert:Oh, it could have been. I was offered a job by senior members of the GRC. It would have meant that I was in on the ground floor of this company. But that wasn't what I wanted to do.
Doel:What was the experience like working in the GRC?
Hubbert:Well, in a way, you might say that I almost wasted a year, because I was doing pretty routine work. But I didn't feel that at all. I was learning something all the time. I wouldn't have done that kind of thing for a longer period. But for that year, I didn't think I was wasting my time. I thought it was a damned good experience. And when I went back to the university, incidentally, I was then given a job of teaching one of these beginning geology courses, which I did all that year, 1928-'29. But along about the spring of 1929, I was studying a bunch of things, including the isostasy problem, cloudy interpretation, and also seismology, in fact quite a series of geophysical things, and I began to stew more and more over the fact that nothing of that sort was being given in the geology department. Or in the university. I was entirely on my own, just trying to dig these things out bare-handed.
Doel:Was there anybody who could give you even some support, for example Bretz or Chamberlin?
Hubbert:No. Not on these things. What they had done was on geological problems, geological overview. But what I was doing was trying to investigate particular problems like the isostasy problem, and some of these deformation problems and they didn't offer anything at all. That was one of the things that was bothering me. I got into a train of thought, along with some of the other graduate students. But I was the ringleader perhaps in the group, of complete rebellion over the state of geology.
Doel:This is interesting. This is after you'd gotten back from the job?
Hubbert:Yes, when I was a graduate student.
Doel:In 1928, 1929.
Hubbert:And here was all of this literature. For example, in geophysics you had the Berichte der Geophysik which was a world-leading journal, had been in operation since 1887.
Doel:Did the library even carry that?
Hubbert:Yes. They had it in the library.
Doel:You could get it.
Hubbert:And the Zeitschrift fur Geophysik, which was newer, but it was ten or fifteen years old or so. You had books on seismology, German, French and a little bit in English. But nothing of that sort was taught in the geology department. You had summaries of some of the results, but none of the more theoretical background, for understanding them. And so the more I saw of this discrepancy, the more I was dissatisfied with the state of geological science there.
Doel:And other graduate students shared your feeling?
Hubbert:There was one or two that shared somewhat, but I was the principal person. So finally along about the spring. Spring of '29, I concluded that I knew enough that I could give a course in geophysics myself. And when it occurred to me, I propositioned Bretz with it. Bretz blinked his eyes a few times and had me explain in a little more detail — I did — and he said, "OK, I'm all for it." I said, "What do I do next?" "Well, you'd better see Bastin, the chairman of the department." I did, and Bastin was a much more cautious person. He had to give it very serious consideration. It required faculty action and so on. After it was all over with, I got an agreement to do it. So I started to work then to organize my notes for this course the following year.
Doel:This would have been '29-'30.
Hubbert:1930. Well, I was working on it in '29, the spring of '29, the summer of '29. It wasn't actually given I guess until the winter term, 1930. Now, I did give the course, and while I was giving it, a man from Columbia University dropped by. They were scouting around for somebody to teach geophysics at Columbia. So I invited him in to my lectures. And so I was invited to come to Columbia University for an interview at the end of the quarter. They gave me a job as instructor in geophysics at Columbia.
Doel:OK. I want to get to that and talk with you about it, but there are a few things I'm still curious about regarding Chicago. What kind of a chairman was Bastin? What kind of a man was he to work with?
Hubbert:Well, he was — it was a mixed sort of thing. He'd been at Chicago. His doctorate degree was from Chicago about 1912. But he'd been with the Geological Survey ever since, and he wound up as head of the metals branch out there, in mining and metals, and they'd gone through World War I. The Geological Survey in World War I was smaller than it is now, and so almost all the work had been shifted over to war work, especially with regard to metal resources. Psychologically, there's an old adage in the military to the effect they fight the next war the way they fought the last one, so they were trying to fight World War I with the equipment of the Civil War. There was no realization in the government that modern warfare was a warfare of technology. They were still thinking of horses. And gunpowder. So actually, the man who did the most perhaps to shake the US government out of that complacency was C. K. Leith. C. K. Leith and Van Hise you know had been the pioneers in the mapping of these big iron ore deposits up in the Lake Superior Region. Then they carried on: Van Hise wrote a book on conservation, I guess, about 1912. That was the period when Teddy Roosevelt and others were much involved in conservation problems. And then Leith got into this through Van Hise and their knowledge of the ore deposits, especially iron ores. The country and the world ran on minerals at the time, and Leith wrote a book called ECONOMIC GEOLOGY in the early 1920's. But during the war he exercised tremendous influence in getting the government to realize that that was what it was involved with, was mineral resources, metals, and energy resources and so on. All right, that's the backdrop. In the spring of 1926, now, Bastin gave a little course called economic geology.
Doel:And you'd taken it?
Hubbert:Since I was majoring in geology, and it was given by the chairman of the department, it was more or less obligatory that I should take it. I hadn't the slightest interest in the subject. Well, I didn't think too much of Bastin. I thought he was a little bit on the dull side and not too bright. And he was a Herbert Hoover Republican, and at the time of the Al Smith-Hoover political campaign too. And I just didn't have a very high regard for him personally. I still don't. But it turned out that that course was one of the most revolutionary courses I ever had in my life. In the first place, it was beautifully organized. He was intimately familiar with the subject. And it dealt largely with Van Hise's Metal Resources.
Doel:Who were you reading in that class? Was it the Leith and other studies?
Hubbert:Not much reading. It was mostly his own lecture notes, lectures.
But they were beautifully organized, and he had an intimate knowledge of what he was talking about. He'd been through this World War I group on metal resources, and these people I think had gotten an enlargement of their own education because they had to push this thing on out to the processing and the uses of these things. And not only that, but also the international relations. You discovered, Germany had been employing these minerals in preparation for World War I several years in advance, when we didn't even know about such things. Well, all right, as it went along, it became more and more apparent — it had never dawned on me, shall we say, that this modern world runs on minerals. I didn't know that, had never thought of it. In fact, being of a non-industrial agricultural background, why, I just wasn't familiar with the intricate details of modern machined war. So it seemed to me more and more obvious as we went along, the immensity of it — in fact, he had us do this kind of problem early in the course. He had us go and get statistical abstracts of the United States and look up the freight hauled by the class 1 railroads of the United States in the last volume.
It turned out to be overwhelmingly products of the mines, including rock and gravel and cement and so on. Just for a magnitude. Now, later on we were dealing with things like iron ore and coal, and he had us make curves of these things, for instance, the local steel plants and cement plants, and also geological occurrences. As I say, this was just a complete eye-opener to me. In one stage, I remember rather vividly we got around to coal. He had a huge wall chart, about so big. It had a plot of US coal production from the early days on up to the present. It looked about like this. I looked at that and my eyes bugged out. And I began to wonder, how long can we keep that up? Well, I went to the original sources, got the year by year data, plotted it on a semi-log arithmic curve and it was a straight line. The doubling period — with an annual rate of about 6 percent-the doubling period was about twelve years. And that was perfectly obvious, that you couldn't keep that up, but just how long, well, how much was there? Well, at that time, you had the old 1912 report of the International Geological Congress, where they had devoted that entire congress to a report on the world's coal resources in the various countries. Each one brought in estimates on the coal in their country. It was the first world survey of coal resources.
Hubbert:In 1912, about. Anyhow, I had those figures for the approximate magnitude of the world coal, and the coal by various geographical areas, countries. I was very strained over this thing and I still am. And so, as I say, my later work with oil brought this into the picture but at this time the data, the statistical data weren't very far advanced.
Hubbert:And coal dominated. The oil was a small percent of the coal. Coal and iron at the time were the big ones, and you could plot coal and iron so that you'd know which one was which, because they were neck and neck. They were the pair. And for obvious reasons. Iron was largely dependent upon coal, to smelt the ore. And so, OK. That was the beginning of my interest in minerals.
Doel:How often were courses in economic geology offered at American universities? Was Bastin's class unusual?
Hubbert:Bastin had two courses. He had this… course called economic geology, and then he had a small advanced course on ore deposits. I never took his ore deposit course. Later on, in 1931 to '37, largely through Bastin's influence, I think, I was offered a job with the Illinois Geological Survey as a geophysicist. Actually I stayed at Columbia and simply worked with them in the summers. But my principal work was in the mining business in southern Illinois.
Doel:That's something that I want to get to the moment we turn to your time at Columbia. For now, I'm wondering if you have recollections of Francis Pettijohn?
Hubbert:Francis came to Chicago about 1929, and so we overlapped there. I never had any of his work. We were personal friends.
Doel:Did he have a large influence on your thinking in geology?
Hubbert:No, not very much. He did on people who worked with him but I never had any work with him. He had a profound influence on his students.
Doel:Did you discuss what you wanted to do in geophysics with him? Was he one of the people you could develop these ideas with?
Hubbert:Not very much. I was trying to say a while ago, that this rebelliousness was about this situation of geology. What I thought at the time was, what's the difference between geology and a subject like physics, for example? Here your physics had a strong quantitative mathematical background, and geology didn't. Geology was largely natural history methods of thinking. At the same time, some of us ran into this famous quote by Lord Kelvin, or Sir William Thomson, in a lecture that he gave before electrical engineers in Britain in the 1880s. He had a dogmatic statement there that was often quoted, to the effect that if you can measure things and give them numbers and magnitudes, you have the makings of a science. But if you can't, why you can hardly claim to [have one]. Well, he just stated it much better than I'm stating it, but it's a famous quotation. We interpreted that to form a distinction [which was a widely held interpretation, even right up to now in academic circles] — and that is, that if you can measure things and give them numbers and use mathematics, you have something scientific, and if you can't, you don't have very much of a science. So geology as of that time was in a primitive stage, and it would never be more until it got over to the physical science stage of being able to use mathematical analysis and so on. Well, I held to that view quite doggedly for about ten years. It gradually became clear to me that it was only half right — the Kelvin thing was a mixture, was half-truth. There are a lot of problems and phenomena in which mathematics is not the way to deal with them. You are dealing with a "who done it?" and geology has many aspects of that. The deciphering of geological history was largely a non-mathematical process, and was one of the greatest intellectual achievements in the history of mankind, with people like Lyell, Darwin, Hutton to mention a few pioneers.
Doel:It's a very different kind of science.
Hubbert:But nonetheless, take the hypothesis of glaciation. Nobody ever saw a continental glacier in North America as in Greenland. Yet the certitude of that hypothesis is just as good as any scientific deduction anywhere. It's based entirely on a "who done it?" with types of clues. After you've done that, you can do some mathematical calculations on the mechanics of ice, but you don't do that in establishing the hypothesis to begin with. So, gradually some years and years later I began to modify my view and modify it continually, to take the reverse of that. You could make an ass of yourself mathematically and quantitatively just as well as by any other method. And that comes out of things like this ground water problem that I wrestled with for years. And this resource estimation we're engaged in now. There are quantitative and analytic considerations. [Tape unclear] About ten years ago, I was given an honorary degree at Syracuse University. Parallel with that, they also dedicated a new geology building over there that had been given to them by a former graduate, and old time friend of mine, Bill Haley. They were dedicating the Haley Building at the same time. They went on to a symposium, which they called a Chautauqua, and I was invited to give one of the papers. At this Chautauqua, they had a new man that they got from Kansas on computers and quantitative statistical methods in geology. This Chautauqua was built around… I don't remember what they called it — quantitative methods in geology, something of the sort. I was invited to give one of the papers. The title I chose was quantitative methods in physics and the physical sciences. [Tape unclear] I cited this background personally… a review on this thing. Lord Kelvin was one of my patron saints. I quoted this dictum, statement of his, and after a while I began to point to the contrary evidences, things like the glacial hypothesis and other aspects of geology, the historical geology. Then I got around to those with mathematical and in some cases physical backgrounds… and other quantitative methods.
Hubbert:The paper was published in the little local house Proceedings of that meeting. The paper is just now being discovered. Once in a while, people come up to me and ask me about something in it.
Doel:I've read that already. It's an intriguing paper.
Hubbert:You've read it?
Doel:Just to turn for a moment to another topic: what funds were available to you as a graduate student?
Doel:Yes. How much of a problem was it to do research then?
Hubbert:Very little, because my needs were few. I started to do a thesis in physics on the accelerometer, strong motion in earthquakes.
Doel:Who were you working with on that?
Hubbert:I was working under Eckhart. I should have mentioned him, physics. I forgot to mention him. He was my foremost professor in that work, Carl Eckhart. But I was kind of floundering around for a thesis. I decided to try to build a seismometer, electronic seismometer, for strong motion accelerations. This was in the spring, I guess, and summer of 1929. It was along about summer and fall of '29 and '30, and then I went to Columbia. I was offered this job in Columbia, and I went there on the 1st of January 1931, and this job wasn't finished. I did get a… given by the physics department, a very sensitive high class DC amplifier.
Doel:You were given this at Columbia?
Hubbert:No, I was given it at Chicago. And that was the only piece of equipment costing any money that I had any need for and I was given that. Well, the main difficulty I was in there was that I didn't know anything about electronics, neither did most of the faculty. Electronics was a thing developed by electrical engineers for radios and that kind of thing. I didn't know anything about it, and I was messing around, struggling around there with equipment I didn't know much about. I was a general neophyte on what I was trying to do, and I didn't get anywhere, I didn't get any credits, till I went to Columbia. And the matter was dropped entirely. I had sort of refused to do a trivial problem, and I was working on a whole flock of things. So finally in 1937, I was on the National Research Council Committee, a committee between geology, physics and chemistry, and out of that came the inspiration to write this paper on the theory of scale models as applied to structural geology, or geologic structures. After I did that, Chicago gave me a Ph.D. for it.
Doel:Gave you your Ph.D.?
Hubbert:After it was published.
Doel:OK. At Chicago do you remember hearing geology instructors talking about whether they were doing science or religion? You mentioned this later in one of your own papers — do you recall who had said this?
Hubbert:Yes. That was a lecture by Kurt Lerner from Harvard. Kurt Lerner came by and gave a lecture to the department, in the main lecture hall. It was all about the interior of the earth, from the grassroots to the center, and he showed you exactly what kind of rock was at every level. I was sitting next to one of the graduate students, bright young lad, and he whispered to me, "Did he say he was a professor of geology? or theology?"
Doel:That's good. Was he one of your compatriots advocating geophysics at the university?
Hubbert:Well, no. He was just one of the kids, graduate students. He was younger than I, but I've known him since he was a freshman, probably.
Doel:OK. One thing we didn't talk about yet is the first paper that you wrote and published, on fault descriptions. How did that come about?
Hubbert:Well, I was trying to remember. It may have been Chamberlin's course in structural geology, but it couldn't have been that. That was published when I was still an undergraduate.
Doel:Right. There was a GSA committee on faults.
Hubbert:There had been. What came out of it was, there was a course being given by Chamberlin, and I have the recollection that it was this course in structural geology, but I don't recall that I took it that early. Maybe I did.
Doel:Well, the paper was published in 1927, possibly after your first year.
Hubbert:No, I think that the paper was published earlier than that. Was it?
Doel:According to your cv, it's 1927. 
Hubbert:Well, you've got the record there. If it was published in 1927, then all right, the course would have been his course in structural geology. We were discussing faults, different kinds of faults and so on. This GSA committee had been appointed ten or fifteen years previously, to do the nomenclature on faults. It was one of the things that we read in this connection. My God it was a hodge-podge if I ever saw one. Every kind of a screwball name for things they could think up, and it was just, I would say, god awful. It was a seminar situation. I was given the assignment I think of reviewing this GSA paper for the class. Well, it struck me that this thing was so confused that most of them had never heard of many of the terms that were proposed. So I reviewed it by asking them questions, what does this mean? What does this mean? Just to demonstrate that the thing was a mess. Then I suggested, why don't we just reduce them down to its elemental, geometrical components? We're dealing with kinematics and geometry. So what have you got? You've got a fault surface, which you regard as a plane. It has a different strike, which is a couple of angles. There's a motion along this surface, which may be down the dip or it may be horizontal or diagonal. So you can simply give numbers using the standard notation of analytical geometry and so on. Really that's all you can do with simple normal type faults or simple thrust faults. I gave this paper, after having gone through this — just miserable GSA committee report.
Hubbert:Chamberlin was so impressed with it, he offered to print it. So I wrote it up for publication at his suggestion.
Hubbert:And incidentally, I don't know if you ever saw this, but here I got my Day-Medal citation. This involved the meteorologists of Princeton, a bunch of meteorologists. Here again I'm blacking out on names at the moment.
Doel:We can check on that. That's fine.
Hubbert:All right. He was chairman of the committee, he picked me for the Day Medal. There was a citation, and it cites this first paper which I regarded as trivial. But to him it was impressive because I used proper analytical methods. [Laughter].
Doel:It was your first paper, as well as a graduate student. That is remarkable.
Hubbert:Anyhow, that's how that paper came about. And the second one came about in my battle with Chamberlin over this Leith thing which Chamberlin took as gospel. I pointed out the thing was physically erroneous.
Doel:One last question I wanted to ask about your Chicago years. Do you remember at any period of time any discussions about Wegener's theory of continental drift? Did that come up at all?
Hubbert:Very, very little. Chamberlin was adamantly stuck on the solid earth. He thought he had geological evidence from one continent to another. He had traveled extensively and done geologic work in different areas. It just didn't support the hypothesis. And I couldn't judge because I didn't have such knowledge. But he was strongly frozen on the solid earth non-floating continents type of thing. Well, in this theory of scale models paper I essentially, what I showed was that even solid rocks, when you look at them on the scale of mountain ranges and continents and so on, begin to act like plastic materials. And I had these simple observations, like this quartzite, solid rigid quartzite. It flowed as if it were highly plastic material.
Doel:That was a powerful memory from Wisconsin.
Hubbert:Out of this, perhaps the principal thing that I accomplished in that scale model paper was to resolve essentially this paradox over this apparently weak earth and this highly rigid earth simultaneously.
Doel:Was that seen as a problem by many geologists on the faculty — this question of the strength of the earth's materials?
Hubbert:Yes, that was a serious problem. For example, we had the evidence of the postglacial uplift, shores of Lake Michigan and so on. Shorelines going up to the north and places where it was pressed down by the weight of the earth and was coming back up. Then we had this troublesome thing of the isostasy problem. Was it real or was it not real? Of course, that was partly followed by this guy Boyd in the Coast and Geodetic Survey, who was not a scientist but a propagandist, in a way. He wrote a lot of foolish stuff on the fixation of the isostasy theory, in the form that the Geodetic Survey used to make their calculations.
Doel:Was he influential at the time?
Hubbert:Oh, quite influential. After all, that was a very great piece of work, and it was accepted internationally as the official figure of the earth in the international congresses on geodesy. The hypothesis, I mean the evidence for the isostatic compensation, was very real, in the gravitation. See, historically that goes back to the triangulation of India in the 1840s. The British carried this triangulation net in England, in India, and then they approached the Himalaya Mountains. Well, they expected the distortions because of the attraction of the mountains. They referred to it as a fraction of the plumb bob but actually the plumb bob was deflected right straight down by definition. But it was deflected with respect to the assumed mass of the Himalaya Mountains, which it was. But when they computed the mass of the Himalaya Mountains, the part that was visible above sea level, and its attraction, the actual deflection was far too small. It should have been much bigger.
So why was that? Well, that led to a series of papers by two different gentlemen, one, Sir J.B. Airy the Astronomer Royal of England. The other one was Archdeacon Pratt of Calcutta. These two men wrote the principal papers on this subject for ten years. Pratt and Airy introduced a hypothesis that the mass deficiency below sea level was equal to the mass excess above sea level, as compared with the uniform density of the earth. And so at this lower density below sea level plus the — would compensate for the weight of the material above sea level, and it would be in about equilibrium. Then you'd have a variable. Of course at that time what you had was the crust of the earth and a liquid interior immediately below. The crust of the earth was considered to be a few tens of kilometers. And so this was their hypothesis, then, that the densities… Wait a minute, no. I was saying that wrong. The densities were the same, but you got the difference of mass by having it protrude farther down into the more dense region. A lot of crustal material protruded downward and displaced more dense material and that contrast was the mass deficiency. That was the Airy hypothesis. The Pratt hypothesis was that this boundary was a uniform level surface, and that the columns above that were varied in density, the mountain being less dense on this column, each column having the same mass and having the same pressure at the bottom. But the boundary columns, such as the mountain ones, were less dense in order to have the same mass, and the oceanic columns were more dense in order to have the same mass. To have the same elevation of the bottom. So that was the Pratt hypothesis.
Well, actually, I think now you'd say that either one is equally good. I mean, you can account for the observed gravity by either one with the proper adjustments about equally well. The ambiguity of gravity interpretations is such that you can't distinguish one of these from the other. So some modern writers follow the Airy hypothesis, some still work with the Pratt. The Coast and Geodetic Survey adopted the Pratt hypothesis, and then it was easier to compute. They made these computations, you see, in their final big study of gravity. At every gravity station they divided the earth into a series of concentric circles, you see, down to the bottom of this area there. And so these circles were at a rather rapidly increasing radius. Right away, the first one was only two or three meters, and then the next one was maybe a few tens of meters maybe and then you got to hundreds and thousands of meters. But they covered the whole earth with these circles. They computed the attraction of each one of these circles and divided it into sectors, of the whole earth, for every station. That was done with the old hand cranked calculators and so on. It's been referred to as a heroic undertaking, which it must have been. What they came up with was a very good adjustment of minimizing their gravity anomalies by these calculations of what they were otherwise. They'd done the same thing earlier but they'd done it with triangulation, worked out in a trigonometric series. But the later ones were based on the gravity net.
Doel:You had been thinking about the question of isostasy? and the materials since the time that you were at Chicago. How did you and Melton begin to collaborate on your paper?
Hubbert:Well, as I said, I think that first summer or so, after I had that course — I don't remember exactly when, I think the summer — he used to come by and visit me. I went in to Columbia. He came by Chicago and he'd stop off, and one of the times he stopped off to do some of his computing, he had me sign on as a helper. Later on, when I had that year off, working in Texas and Oklahoma for these seismic crews, he spent the winter in northern Oklahoma, where the university is located. We only had one surveying crew and instrument, so we were working from practically daylight to dark. So I trained one of my assistants to run the instruments, and so I would work maybe three or four days a week, from daylight to dark. I did the computing on my day off and whatever other time I had. I worked with Frank Melton on this isostasy problem. Out of that we wrote one other paper. That's the time when the oil companies were just beginning to start in with the experimental value work. They didn't know very much about these various types of reductions. I wrote a little paper on the various types of gravity reductions.
Doel:Right. That was your third paper that you published.
Hubbert:I believe so.
Hubbert:We published that jointly. And then we were working on this isostasy problem and Melton was away for maybe just a summer, maybe a year. I think a year in Europe. I was working on it by myself. I got onto some papers by an Austrian, of what I thought at the time a fairly exhaustive treatment of some aspects of this. So I tied onto his work.
Doel:This was F. Hopfner?
Hubbert:Hopfner. I wrote the paper while Melton was in Europe. He came back and decided that I should be the senior author of it, and it was published. I haven't gone back and re-read it, but I'm inclined to think that it was wrong. I was operating on erroneous premises, but I haven't gone back and restudied it in years. Anyhow, I've kind of dismissed it from mind as no significant achievement.
Doel:Do you mean the paper that you authored yourself, the fourth paper?
Hubbert:I'm talking about the Hopfner thing. And as I say, I'm not sure, it was criticized by Vening Meinesz, the great Dutch researcher on the subject, and he had a very low regard for Hopfner's work. I never had an opportunity after I knew more about it to pursue the matter further, and so I'm willing to say that I went off half-cocked.
Doel:Did you have a chance to talk with Vening Meinesz about that? Did you meet him in person about that time?
Hubbert:Not on that subject. But I first met him personally when he came to get the Penrose Medal right after the war. And I believe I met him then, the first time I'd ever seen him. He was so poor from starvation that his clothes were hanging loose on him. The Germans had nearly starved him towards the end of the war, taken all the food supplies. And at that time, great big Vening Meinesz was seriously reduced in weight from hunger. His clothes were drooping on him. All right. The first time that I really had a visit with him was — let's see, when I got the Day Medal, I believe he was there.
Hubbert:I think he was in. This was peculiar. The Geological Journal can never quite make up its mind how to do these ceremonial things, and they frequently had them as part of the dinner ceremonies, again with a presidential address and so on. By the time I got there, they decided to have a minor presentation at 4 o'clock in the afternoon, and not associated with anything else. There was only a handful of people left and one of them was Meinesz. Anyway, we had a nice visit then. I don't know whether we had dinner afterwards or something. We had a very pleasant visit. Well, I was in Europe summer of 1955, when I went on a trip across and through the Alps, and that's when this idea struck me of the water pressure supporting the overburden in these big overthrust faults. This thing had hit me when I was in the Alps looking for those big overthrust faults, and then read about it. The question arose, as I was thinking about this thing that night, I wonder how much overburden there must have been. Right now these faults are cutting through the mountain peaks. But how much rock must there have been on top at the time? Probably several kilometers. In that case, I wonder what the water pressure must have been? It was almost inevitable, it couldn't be anything except the flotation of the overburden. It led to that logically. And my God, that's the answer to this old enigma of the mechanical impossibility of pushing those big blocks of rock!
Doel:This is something that I wanted to save for when we can devote an entire session to ground water hydrology.
Hubbert:After this, I was in Holland at a big conference, a week-long conference of Shell, and I got a note from Vening Meinesz inviting me to his house for dinner. I had an evening with him. In the course of that, late afternoon and evening, I mentioned this thing about the Alps. He said, "Have you published that?" I said, "No, I just thought of it." He said, "Please do."
Doel:That's good. What sort of man was Vening Meinesz?
Hubbert:He was a very — you might say a loveable man. The Dutch divided themselves into different types, and one type was out-and-out Prussian mentality, manner. Another type was a gentle type, and Vening Meinesz was the gentle type. He's a Friesian. The Friesian Islanders.
Doel:What impressions do you have of his scientific style? The way that he approached his problems, the research that he did?
Hubbert:I don't know. It was very good. And I have no criticism of him scientifically.
Doel:Did you talk about methods of doing geophysics when you spoke with him?
Hubbert:Not much. After all it was just one evening, social gathering, and I don't know that we got into this subject.
Doel:OK. I would propose one of two things right now. We could talk about the early experiences you had in Columbia. But we've covered now almost four hours of recording, and I'm concerned that we not go on too long.
Hubbert:Well, I suspect maybe it would be better to sign off now, and start in on new topics next time.
That sounds good. OK.
M. King Hubbert, 1927, "A Suggestion for the Simplification of Fault Descriptions." J. Geol. 35, No. 3, pp. 264-269.