Interviews with Australian scientists

Professor Mervyn Paterson
Geophysicist

Professor Mervyn Paterson is a geophysicist who has led Australian research into rock mechanics and pioneered instrument development over the last fifty years. He was born in South Australia in 1925 into a family of wheat farmers. He attended Adelaide Technical High School, then The University of Adelaide from 1941 to 1943.

He began his career at the CSIR Division of Aeronautics working on the physics of metal fatigue, a foundation which shaped his entire career.  He received a PhD from The University of Cambridge in the UK on x-ray diffraction effects of deformation metals, and pursued postdoctoral studies in Chicago in the USA. He returned to work at the newly-named CSIRO, but soon moved to the Australian National University, where he stayed for 31 years in the Research School of Earth Sciences. During this time he developed instruments to test rock deformation, which subsequently led to a ‘second career’ as owner and manager of Paterson Instruments P/L, a company specialising in building scientific instruments.

Interviewed by Professor Kurt Lambeck in 2006.

Contents

Studying rock deformation
The importance of crustal rocks
Influences in rock deformation studies
Early life and family background
Widening horizons at high school
From university metallurgy to CSIR research
A Cambridge PhD in material science
Chicago: the postdoctoral student meets his wife to be
Transition from CSIRO to the ANU
Moving firmly into experimental rock deformation
A new career in equipment building
Whither rock deformation studies?

Teachers notes to accompany this transcript.

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Studying rock deformation

I think it is fair to say that Mervyn Silas Paterson is Australia’s leader in research into rock mechanics under a range of laboratory and geological conditions. And over some 50 years he has pioneered apparatus developments that have been adopted world wide and are still directing the research of this field.

He was first appointed to the Australian National University in 1953, becoming a professor in 1987 – when professors were still few and far between and the title actually meant something. He was elected to the Australian Academy of Science in 1972, and during his career he has received a number of international and national awards in recognition of his work, perhaps most notably the Walter Bucher Award of the American Geophysical Union.

Mervyn, it is appropriate that we start with your science. I recognise that it is futile to try to summarise your career in a few minutes, and the details would probably be better set out elsewhere. But perhaps you can give us an overview of what you have been doing all these years, and an idea of how it relates to geological research in general.

I really started as a metallurgist and later got into material science, as it is called nowadays. Coming to the ANU in 1953 represented a big change in direction for me, because that was when I got into experimental rock deformation studies.

We were trying to understand how rocks deform – to understand geological processes, because during mountain building rocks get really screwed up and twisted and bent. The object in the lab is to try to understand what the processes are, and what sort of strengths rocks have. How strong is a rock under geological conditions? What sort of forces do you have to apply to deform it?

So that is the sort of thing that has kept me busy over the years.

If you go to a road cutting and look at how the rocks there have been folded and faulted, how do you relate this back to your laboratory experiments?

Well, you have to imagine what the conditions were at the time when those rocks got deformed in that way, when they were deeply buried in the Earth, perhaps even at the bottom of the Himalayas. A rock normally is rather brittle – if you try to bend it at atmospheric conditions, it just breaks. So to do our experiments on plastic deformation of rocks we have got to find high-temperature, high-pressure conditions, say thousands of atmospheres of pressure and 1000 degrees in temperature. You can bend a rock just like a piece of copper if you have the right conditions.

And where does that place you in the Earth?

Perhaps halfway down in the crust, 15 to 20 kilometres. But once you are under those conditions you are studying processes that are no longer so pressure dependent, and so you can apply the results in thinking about deformations deeper in the Earth.

How do you extrapolate from your laboratory work to the geological environment?

That’s a very tricky one, because we don’t have the geological time in which to do experiments. That is where the detailed study of the structure of the rocks and the specimens and the crystals in them becomes very important, because we want to understand the mechanism of the deformation. There are various ways in which a rock could deform at the atomic or crystal structure level, and we need to look in the microscope for evidence of what processes occured in the crystals of the rock. That tells us something about what particular deformation mechanisms were effective.

Then we can go to rocks in the field, do similar studies there, and try to come to conclusions as to what the mechanisms of deformation were. If we can persuade ourselves that the same mechanisms were operative in geological deformation as were operative in our experiments, we are entitled to extrapolate our very short-term experiments – hours or days – through to geological time of millions of years.

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The importance of crustal rocks

During your career there has been a major revolution in the earth sciences as the plate tectonics hypothesis has developed. How has your own science been influenced? Has it made the outcomes of what you are doing more relevant?

I had got into this field about a decade before the plate tectonics revolution so it didn’t greatly influence what we were doing. It has been extremely important for the context of geological studies, which I suppose has impacts on the laboratory work, but plate tectonics is really very large scale and we work at the intermediate and small scales.

I guess one consequence has been to move the emphasis in the earth sciences away from the crust into the mantle – to look at convection, for example, the dynamics of the mantle. Do you ever think of trying to do deformation studies at the greater depths and temperatures that are more representative of the mantle?

Well, there is no problem about the temperatures, because those we work at are at least the same as in the upper mantle. And the pressures are not a great factor in extrapolating down to greater depths, because the plastic deformation processes that we are looking at are not so pressure sensitive. It is exceedingly difficult to do experiments at the higher pressures. People are doing that now: a group in America and another one in Bayreuth, Germany, are doing experiments at much higher pressures. But they are much cruder experiments. I prefer to stay in a regime in which I can do more precise measurements.

I guess there is a question of choosing materials. If you are working at crustal depths you are looking at crustal materials; to work at mantle depths you have to look at mantle materials. Initially you have been working mainly on calcite, and later on quartz. How pertinent are these to understanding the Earth?

They are very pertinent in the crust. And I must take issue with the notion that all the important questions are down in the mantle. Most of the geology that we see is in the crust so I am a firm believer in the importance of working on crustal rocks. But we have also done a lot of work on olivine rich rocks, and olivine is the principal constituent in the upper mantle so we haven’t neglected that. David Kohlstedt, from Minneapolis, spent a sabbatical here at a time when we had already got into working on olivine rich rocks, through work by Pram Chopra. Since then Dave Kohlstedt – using one of our machines – has taken up this sort of work in a big way in Minneapolis, which is now the centre of work on olivine rich rocks.

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Influences in rock deformation studies

Over the years you have had a tremendous impact on students, staff and visitors, many of whom have gone on to positions of distinction and influence in Australia and overseas and have shaped the discipline of rock deformation studies. To what do you attribute this influence, and what lessons can we draw?

That’s a bit hard to answer [chuckle] (assuming that I have had much impact on people). Comments from one or two of my colleagues suggest that they have learned something about how to be meticulous in thinking and in examining and analysing problems. I think it is a matter of attitude and of a disciplined analytical approach.

And of your ability to marry the instrumental development with the science?

That’s all part of the same approach. When you want to attack a problem you have to develop the procedures for attacking it, and if you are an experimenter that means developing experimental equipment.

I think it is fair to say that your research work is characterised by asking critical questions and then designing experiments in search of the answers. Can you give us an example or two of that?

Well, take for example the crystallographic preferred orientation in marble. Marble is made up of crystals of calcite and in many cases the crystallographic axes are lined up, they’re not just random. It is thought that they are lined up during the deformation. In the lab we can put pieces of marble – calcite aggregates – into the apparatus and deform them, and then use X-rays and so forth to measure the preferred orientation. In that way you can actually relate the preferred orientations that you see in a marble specimen to the sort of deformation that it has had. That enables you to go into the field, pick up a piece of marble and say, ‘That’s probably been deformed in this way.’

What have been your most important contributions so far in this field?

I like to think my work on quartz has been important. Quartz is really one of the most difficult of materials to deform and I don’t think we understand it altogether yet, but I think I have made a contribution there. Another one that comes to mind is some work we did very early on with Barry Raleigh, on deformation of serpentinite at high temperature. That work brought up ideas about how deep-seated earthquakes may occur and has had quite a bit of attention over the years.

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Early life and family background

Going back in time, Mervyn: you grew up in a ‘one-horse town’ in South Australia. In fact, you had to share a horse in order to get to school. Have any aspects of that early environment shaped your subsequent life?

Early life in Booleroo Centre, South
Australia: Mervyn holding his baby
sister.
Booleroo Centre: Mervyn's primary
school.

I grew up in Booleroo Centre, a town about 300 kilometres north of Adelaide in a marginal wheat farming area – very marginal, I think. We lived right on Goyder’s Line, which was supposed to be the limit to where you could grow wheat.

My forebears had gone up there in about 1875 when the area first opened up for wheat farming. So I came from a farming background and grew up on a wheat farm. The early 1930s were fairly tough years, however, when we had a lot of droughts and dust storms as well as economic depression, so things weren’t very easy on the farm. But it was a great background in a way.

I went to local primary schools: small country schools with about 14 children in each of them, all classes in the one room with one teacher. The older kids got told off to teach the younger ones, and it was a cooperative venture. That’s not a bad way to start off, actually. It teaches you a lot of self-reliance and so forth.

We had to travel quite a long way, though, and yes, I used to go to school on a horse. In fact, during the Depression our farming went back to the use of horses.

We escaped from going bankrupt in 1936 and moved down to Adelaide Hills, where I did my last year and a half of primary schooling at a very small, one-room school with a remarkable teacher, Max Wardrowski. He had a university degree, which was exceptional – all the teachers before that had been young women who were more or less just out of high school with a year’s teacher college training. But because Max had a degree I became aware that universities existed and that a person could have an academic career.

Even earlier, I understand, your background includes the very foundation of Adelaide. Have I got that story correct?

Yes, one of my great-grandmothers came out in the first year of the colony. All my forebears were in South Australia by the 1850s. Half of them were from Scotland, a quarter from Wales and the rest from England, especially Somerset I think, with a great-great-grandmother from Ireland somewhere along the line. They were all farmers. My father used to have stories about the amount of cider that the ‘Somerset’ lot would drink during the summer.

I gather that your forebears were fairly staunch Protestants. Did that rub off on you and have any influence on your life?

Family portrait: Mervyn stands on the left
behind his mother.

[chuckle] I wonder. I think it’s deep down. I think there were Cornish Methodist connections going right back to John Wesley himself. Certainly I grew up in a context of Protestantism. My father was a Methodist lay preacher, so we used to be regular churchgoers. I’m not particularly a churchgoer these days and I suppose I have become a bit agnostic, but I don’t regret that as a background.

Mervyn, in reading obituaries of great scientists I am struck by how often their background has been very similar to yours – they have come from small towns, gone to small schools, had a not particularly academic environment. What is it about such a background that produces outstanding people?

I think one of the important things is self-reliance. When you come from such circumstances you do have to learn to make your own way in many respects.

I believe that even today you still walk to and from work. Do you think that mothers have to stop dropping their children at school and picking them up, and let them walk five miles?

[chuckle] Well, I don’t think walking five miles does them any harm! It probably does them quite a bit of good.

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Widening horizons at high school

Did you go on to a local high school?

There was no high school in our area so I went away to the Adelaide Technical High School. It was a select entry school with emphasis either on engineering or on commercial activities. (Max Wardrowski had probably brought our attention to its existence.)

When I was about to start at high school there was a polio epidemic so school was a little late starting that year. We had correspondence lessons for a while.

The school was very good, with high standards, and I had very good teachers there. For example, my teacher in the first year was Max Bone, who was subsequently Director of Technical Education in the South Australian government. Another outstanding teacher was the chemistry teacher, Dougal Slee. I learnt a great deal from him.

I suppose I gradually developed an interest in pursuing further studies. The high school didn’t teach any foreign languages, so when I got the idea that I might be able to go to university I had to go and do Intermediate French at night school while I was doing my Leaving. I somehow managed to pass it.

That must have stood you in very good stead later on, because your French connections are well known. At some stage during high school you had to make a choice, I understand, between going to university and joining your father as a farmer.

Yes. During the Intermediate stage he came to me one day and said he was interested in a new property down in the south-east of South Australia, a bigger property which would have been more than he could manage. Was I interested in going in with him in that? Well, I thought that I would like to do another year at high school yet [chuckle] and passed that up. I guess by that time I was getting doubtful about pursuing a farming lifestyle anyway. I had seen plenty of how tough a life it was, the financial stringency and so forth.

So that was a turning point. I guess I oriented myself to a non-farming life from then on.

I guess ignorance was bliss – you didn’t realise how tough and difficult an academic life could be. You have no regrets about not becoming a farmer?

No regrets. I did think about going on to agricultural science, because I still was very interested in that sort of thing. My father had been very active in the local agricultural bureaux that used to keep farmers up to date with the latest ideas about farming. But one of my teachers, Stan Tiver, had a son who had just finished agricultural science and couldn’t get a job. (This was just before World War II.) Well, considering all the unemployment of the ’30s, the really important thing about a career was to be able to get a job! That ruled out agricultural science.

Dougal Slee had inspired me very much in chemistry and I thought that would be a good field to go into, but doing an academic chemistry degree didn’t seem to be the avenue to a job either. So I did the next best thing and chose metallurgy, which involved plenty of chemistry and also had the possibility of a job at the end of it. And on the basis of that decision I entered the university.

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From university metallurgy to CSIR research

As I understand it, when you went to Adelaide University you were remarkably young by today’s standards. What are your memories of university life?

[chuckle] I was just 16 when I started. I didn’t take much part in university life in those days, except going to lectures and studying. It was very much a nose to the grindstone period. I used to do all right at it, though.

Degree portrait: The University
of Adelaide, 1943.

I started at the university in 1941. The end of that year was Pearl Harbor and the fall of Singapore, and the first vacation in 1942 we actually spent digging trenches in the grounds of Adelaide University because the Japs were coming down what were then the East Indian islands at an alarming rate. So the university engineering courses went into four terms a year, and the university shortened the course and gave an interim Bachelor of Science (Engineering) which I finished in ’43.

Were you called up for military service?

I was called up, examined and pronounced A1, but as a metallurgy student I was sent back to the university because that was a reserved occupation. A metallurgist was supposed to be making cartridge shells and things, and wasn’t allowed to join the Army. (I didn’t protest about that.)

After university you joined the Aeronautical Laboratories at Fisherman’s Bend, Melbourne, where you worked on the physics of metal fatigue. I understand that that was quite a remarkable place and going there shaped your subsequent career.

Yes, that was a real turning point. Our university course had been what one might call fire and smoke metallurgy – all smelting and ore dressing, extraction metallurgy, with practically nothing in the way of studies on the properties of metals. But in my last year at the university I happened to pick up in the bookshop a newly published book by C S Barrett called Structure of Metals, and that was an absolute revelation to me: I’d never heard about crystal structures in metals in my metallurgy course. It was an inspiration, and was partly the reason I moved over into the physical metallurgy field.

This move resulted also from having second thoughts about pursuing a primary metallurgy course. Professor Gartrell had lined me up a job at the Mt Lyell copper mine, doing studies on flotation of copper ores – which was right up my street, the thing that interested me most in metallurgy. But I got cold feet about spending the rest of my life in a mining town at that point, and Mt Lyell was about as remote a place as you can imagine, on the west coast of Tasmania.

Then I became aware, probably from an advertisement, of an assistant research officer post at Fisherman’s Bend in the CSIR Division of Aeronautics, and I went there in the last year of the war. The lab had been going for about four years, I think. There was a remarkable galaxy of talent at that place, a real research environment, with people like George Batchelor and Alan Townsend.

They both went on to Cambridge and to great things.

Yes, very well known in the field of turbulence later on. There were a lot of people in mathematics; a lot of students of Tom Cherry, from Melbourne University, were there. Oh, it was a very stimulating place.

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A Cambridge PhD in material science

For your PhD you went to the Cavendish, in Cambridge. Did that mean you had to leave your position at CSIR?

Only temporarily. I went to Cambridge on an Angas Engineering Scholarship established by the Angas family of Angaston in South Australia – who had actually brought my great-grandfather out in the 1850s.

And that closed the circle.

Yes. The scholarship, however, still paid about the same amount of money as it did when it was established in the 1890s, and it was totally inadequate support. So I also got a CSIR studentship to make the Angas up to the value of their studentship for me. That was very good.

Can you tell us anything about your time in Cambridge? Did any particular events or individuals shape your future?

University of Cambridge days: Mervyn is seated second from the left.

Going to Cambridge was a new step, and for me a step into the university life. While I was at Adelaide University I lived with my grandmother and life was mostly just studying. But in Cambridge one came in contact with all sorts of people and enjoyed the college life. For example, a couple of my very close friends there were Sahkar – subsequently the editor of the Times in India – and Abuticknama, who became Vice-Chancellor of the university in Colombo, Sri Lanka.

I went to the Cavendish to work with Orowan. I probably got to know about him from Walter Boas (a one-time Fellow of our Academy here) who had been a fellow student of Orowan’s in the Technical High School in Challottenberg, Berlin, in the 1920s – a great period in German physics.

Mervyn receiving his PhD
(on X-ray diffraction effects
of deformation metals) from
The University of Cambridge.

There was a very interesting group of people around Orowan in the Cavendish at that time. One of the people I used to share an office with was Rodney Hill, for example, who was just finishing his PhD in plasticity theory. Norman Petch was another interesting person. Robert Cahn is very well known in material science nowadays; he also shared that office. [chuckle] It was a very stimulating time, and I very much enjoyed living in Clare College and associating with the people there.

When you went to Cambridge was there again a change in research direction?

Going there was essentially a new orientation for me. It provided me with a new direction, working in X-ray diffraction effects of deformation in metals.

Actually, I didn’t go there with a thesis topic in mind, and initially Orowan said I should work on the mosaic structure of crystals. Well, I spent about six months bashing my head on this and trying to understand the dynamical theory of X-ray diffraction and so forth, but I wasn’t really getting anywhere. So he suggested one day that I look at the X-ray line bordering in copper deformed at liquid nitrogen temperature. I picked that up and I managed to extend it out to a PhD.

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Chicago: the postdoctoral student meets his wife to be

After Cambridge, then, you returned to Australia.

Yes, I came back to Fisherman’s Bend for a year. While I was in Cambridge, CSIR got its O and became CSIRO, and when I came back it was to the Department of Supply, because CSIR hadn’t been seen as secure enough for aeronautical research. It was all right during the war: we didn’t even have a guard on the gate in those days!

Afterwards you went to Chicago for postdoctoral studies. Why did you pick Chicago? What was going on there?

That came about by chance. I think Orowan had received information about the postdocs going in Chicago and mentioned me, and I said yes, I might be interested in that. So he wrote off and they offered me a postdoc. But I thought I was committed to go back to Fisherman’s Bend at that time and didn’t take it up immediately. I was already in the boat on my way back when I got a cable from Fisherman’s Bend saying they would okay me to go to Chicago. [chuckle] Well, I held them to that and a year later I went.

In Chicago I actually worked for a year with C S Barrett, the man whose book had inspired me earlier on.

The CSIRO were quite content to encourage you down this path?

Yes, they agreed to it. They had been cooperative all along.

Not only did the Chicago year change your science, but I believe it was in that big and foreign city that you met your wife to be.

Yes, that’s another opening-out of one’s life. I was a Protestant colonial [chuckle] from remote parts of the Earth, she was a Hungarian Catholic with all the cultural background of Europe, including food.

So this was the civilisation of Mervyn, was it?

Oh yes, I’m sure she’d like the idea that she had civilised me.

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Transition from CSIRO to the ANU

From Chicago where did you go?

I went back to Fisherman’s Bend. In a sense I spent about eight years at Fisherman’s Bend, but for half of that I managed to be overseas.

What did you work on this time?

I started work on the more fundamental aspects of fatigue in metals. I was looking at reverse deformation effects, studying single crystals and pulling them back and forth, looking at the changes – defects and so on – in them. Actually, I spent much of that time perfecting a machine which I later brought up to the ANU and continued to use here. (My first research student did his PhD on that machine.)

We come now to your time at the ANU. You have been at this university for longer, possibly, than anybody else.

Except Frank Fenner! [chuckle]

Would you care to make any comments about what you have seen over this period and perhaps how science was done in the early days compared with today?

There has certainly been a lot of change over the years. Part of it is associated with the increasing size of the place. In the early days one knew everybody – I even knew all the people in Pacific Studies and Social Sciences, whereas I don’t know anybody over there now. One was linked in more broadly to the university community in those days.

Finance was never really a problem: the university was quite well funded, and funded in the institutional way so we didn’t have to spend our time writing grant proposals and so forth. And we were starting off in new fields, largely, so there was a lot of freedom in choice. The department head, Jaeger, would appoint somebody with an idea that he might work generally in, say, seismology but what he did was up to him. [chuckle] He had to formulate his own problems.

Listening to you, I reflect on how similar many aspects of my own career were, despite there being a time difference of 20 years or so. But it seems to me that in these last 20 years things have moved much more rapidly than in earlier periods.

Well, life was more leisurely. I think that is a difference in the research environment nowadays – people have to work much harder. I suppose they’re all stimulated by each other and have less time outside the lab. At Cambridge we used to go off and play tennis in the afternoon, but here we don’t have time for that.

Is the work any better as a result?

The quantity may be greater, but I’m not so sure about the quality.

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Moving firmly into experimental rock deformation

You were appointed to the ANU by Professor John Jaeger, who today has reached almost mythological standing in the Research School of Physical Sciences. Can you tell us something about the circumstances of your appointment to the then Department of Geophysics? It would be unusual today for someone to come into this field from outside the earth sciences community as you did.

It would be somewhat unusual, yes, but it can happen. The background to my coming here goes right back to the beginning of the university and the setting up of the school. It was decided that geophysics would be one of the areas included and a meeting was held in Canberra to discuss where it might go. One of the people brought in to that meeting was Tuzo Wilson, a famous geophysicist from Canada, who suggested that experimental rock deformation would be a good field for the new university to enter.

Oliphant, the first Director of the school, took this up. And when he appointed Jaeger, who arrived at the beginning of ’52, he passed this on, together with the thought that it would be worth writing to Orowan for possible names. (Oliphant had known Orowan before the war by giving him a place in Birmingham when he came as a refugee from central Europe.) Orowan was my PhD supervisor in Cambridge, and he put my name into the ring. So I got a letter out of the blue from Jaeger, asking me whether I was interested in this field. And that’s how I came here.

No advertisements, no applications?

There may have been an advertisement, I’m not sure.

When you got here, what were your marching orders?

To work in experimental rock deformations – nothing more specific than that.

And starting from scratch, no equipment?

Yes. There was nothing in the laboratory at that time. I first got an X-ray diffraction outfit and then started thinking about deformation rigs. I built two or three rather primitive ones before I finally got onto the sort of apparatus that I use now in the lab.

Was this a new area of apparatus development, or did such rigs exist?

There are two pioneers that one must mention. One is von Karman, whose experiments in about 1908 were quite out of their time. The other is David Griggs, who started in Harvard in about 1935, with inspiration from Bridgman on the experimental side. When I came to the ANU, Griggs had been in UCLA since the late ’40s and he had the experimental deformation laboratory in the world at that time. After about four years, in 1957, I had the opportunity to go to Griggs’ lab and make contact with him.

So you weren’t daunted to enter this new field from outside the area?

Well, from the physics point of view I wasn’t [chuckle] because I was really interested in getting into deformation of non-metallic materials. From the technological point of view I was rather daunted; I felt I didn’t know anything about high-pressure experimental work and I was a little hesitant.

How long did you take to get your first publications out?

At first I used the piece of apparatus that I brought with me from Melbourne to work on reverse deformation of metals, an aspect of the fatigue of metals work that I had been doing at the Aeronautical Research Laboratories at Fisherman’s Bend. I carried on with that here for a couple of years while I was accumulating equipment for the experimental rock deformation work, and I got a publication out on that. But it was two or three years before I got anything out on the rock deformation.

The Australian National University days:
Mervyn using a rock deformation instrument.

How would you have fared in today’s climate of Australian Research Council reporting et cetera?

[laugh] I don’t think I could have developed any of the equipment I have now, because I am very slow at things and it takes years to make these things work.

I guess a lot of the work in the School of Physical Sciences was characterised by long-range, very careful instrument development and the science was often very slow in coming. But when it did come, it was invariably outstanding.

And all backed by superb workshop facilities and laboratory assistants.

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A new career in equipment building

Can you tell us something about your time since formal retirement? I say ‘formal’ because I know that you have not gone fishing but have developed a new career as a builder of scientific instruments.

Well, I had many research students and sabbatical visitors over the years who used the high-pressure equipment that I’d designed and had built in the lab, and they seemed to manage it quite well. It seemed to me that the equipment was reasonably user friendly, and I knew there was very little such equipment about.

I am talking about equipment for deforming rocks at high temperature and high pressure. It is basically a pressure vessel, a big cylinder of steel, in which one generates a high pressure. The pressure medium is argon gas, and when you pump that up to 3000 or 5000 atmospheres it has about the density of water – that is really high pressure for a gas. Inside the pressure vessel you have a furnace which raises the temperature to 1000° or so. In effect, you operate a mechanical testing machine in that environment, applying directed stresses to the piece of rock so that you can plastically deform it. Then you have to measure the forces involved, and we do that inside the pressure vessel so as to avoid problems with friction and pistons.

That took many years of development. I was conscious that although a number of people over the years had set out to build such machines, many had never worked, so I thought that there was room for one that it was viable. So before I actually retired I had the idea that we might go commercial with it.

The Instrom company, a big testing machine company in England, expressed interest in it for a while but finally they said that they liked to make machines at 100 a year [laugh] and they lost interest in my much smaller proposal. I mentioned to a friend of mine in the United States that I was thinking of giving up, but he said, ‘Well, why don’t you do it yourself?’ After some consideration I thought, ‘Why not?’ and that’s how it came about.

So how many have you been making a year?

About one. [chuckle] But we have made 12 so far – they are in England, Germany, Switzerland, France and the United States so far – and we have got feeler expressions of interest from China and Italy. The ones in use are all in earth science departments except the one in Poitiers, France, which is in a material science department. I have just come back from a meeting in Orleans at which the Poitier man gave a talk about the work that they were doing.

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Whither rock deformation studies?

You have witnessed 50 years of change in rock deformation studies, and 50 years of change in the earth sciences. Where are things going now?

Things are already going in the direction of higher pressures and higher temperatures for application to deep material of the Earth – in my view, a pretty limited field. Once you have solved one or two problems there, that may be the end of it. The crust of the Earth has infinite variety in it and I think there is a lot still to be done.

What are the big issues that have to be resolved?

I don’t know whether they are big issues but we do need a lot more understanding of how polymineralic rocks deform. So far we have been doing very simple things like marble, which is just an aggregate of calcite; quartzite, which is just quartz; and a dunite which is just olivine. Now we need to do more on rocks which are mixtures of crystals, for example granite, which has quartz and feldspar and micas all in the same rock. We don’t really know very much about the deformation of such materials.

Mervyn, you have had a remarkable life and continue to do so. If at any stage you could have changed directions, would you have done anything different?

I’m not sure that I would. I think life consists of taking the opportunities that arise. If I had been given different opportunities I suppose I’d have gone in different directions, perhaps into history or something like that.

I guess there were no jobs for historians, back in the late ’30s.

[chuckle] Well, some people survived in that period.

Yes.

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