Charles Angas Hurst was born in Adelaide in 1923. Hurst attended the Scotch College, Melbourne where he graduated dux in 1940. Hurst then enrolled at the University of Melbourne but his studies were interrupted by war. In 1942, he enlisted with the Royal Australian Air Force in radio location. After completing a radio physics course at the University of Sydney, a radar course at Richmond and officer training at Bradfield Park, Pilot Officer Hurst was stationed firstly on Normanby Island and then Manus Island, Papua New Guinea (1942-46).
After the war, Hurst returned to complete his studies at the University of Melbourne, graduating with a BA Hons (1947) and a BSc (1948). He was then awarded the Aitchison Travelling Scholarship from the University of Melbourne which allowed him to travel to Cambridge for his PhD studies. He was awarded his PhD in 1952. Hurst returned to Australia and the University of Melbourne to take up a position as senior lecturer in the Mathematics Department. In 1957, Hurst moved to the Mathematical Physics department at the University of Adelaide. He was appointed here firstly as senior lecturer (1957-60), then reader (1961-64) and finally professor (1964-88). Hurst was made professor emeritus in the department of Physics and Mathematical Physics in 1989. Professor Hurst passed away in October 2011.
Interviewed by Professor Bob Crompton in 2010.
Contents
My name is Bob Crompton. I am here to interview Professor Angas Hurst, a distinguished theoretical physicist, on behalf of the Australian Academy of Science. We are sitting in a room in the Department of Physics at the University of Adelaide, very close to where we both worked when I first came to know Angas, which was in 1957.
You were not born in Adelaide, were you?
Yes, I was born here. I left here when I was six months old. That wasn’t my doing, of course.
Where in Adelaide were you born?
I was born at Unley Park, I suppose it was the Unley Park hospital. I stayed there (in Unley Park) with my grandmother.
Is that where your parents were living?
No. They had come back from Cambridge and then went off to Melbourne to the Serum Labs. We moved to Melbourne in 1923.
Tell us something about your father and mother.
My father was the second eldest of nine children living up at Paracombe. My grandfather was an apple orchardist. My father, at the age of seven, got ‘infantile paralysis’, so he was not able to work on the orchard. He went to the Houghton school. Then he went to Adelaide High and did so well that he went on to the university. He did so well at university that he decided to go to a job in Indiana. He got married just before he was due to go. My mother and father went to Sydney to catch the boat and there was a shipping strike, which lasted for several months. They sat up in the Blue Mountains, waiting for the shipping strike to end. Finally they said, ‘Blow, going to the United States. We’ll go to England.’ So they turned around and went to England. My father had letters of introduction to Sir William Bragg, so he went and talked to Sir William Bragg. Bragg said, ‘Why don’t you go to Cambridge and do a PhD?’ So my father went to Cambridge and did a PhD with Professor Riddiell. My father was the first South Australian and the third Australian to get a Cambridge PhD. Starting from an apple orchard, that was pretty good!
Amazing. What about your mother?
My mother’s father, my grandfather, left school when he was 14 and then got a job in a timber works. Then, in collaboration with a friend by the name of Walter, he started up a timber firm called Walter and Morris, which became a very well known timber firm in Adelaide.
I knew that name very well when we lived in Adelaide. Is the timber firm still going?
No. They hired a smart bloke who went and lost all the money. Grandfather died in 1917. The trouble with him was that he was an ‘Edwardian’ father. He insisted that the eldest daughter, who was very scholastic, should stay home and help her mother; the eldest son, who was very musical, should run the business; and the youngest son, who was very smart and businesslike, should become a medico. He got everything wrong. The worst thing of all was that he insisted that my mother come to the Adelaide University to do botany, and she managed to fail every subject. But whilst at Adelaide University she met my father, who was assisting Kerr Grant as a lecturer in physics. Kerr Grant and my father were the entire physics department back in 1919.
That’s where your father and my father met?
Yes. They knew everybody in Adelaide.
Was your mother from Adelaide too?
Yes. Their name was Morris and the original family goes back to 1797. But they came out, in about 1850 or so.
You did most of your schooling in Melbourne?
We moved to Melbourne when I was six months old because, as I said earlier, my father had taken a job at the Commonwealth Serum Laboratories. It was decided that I should go to Scotch College because that was a good school. It was within walking distance – about a mile – so I used to walk to school. I started at the age of six and went on until 1940, when I was 17.
What about some of your recollections about those early years?
At the age of seven I got six on the backside from the junior school headmaster, for which I have never forgiven him. Apart from that, I had quite a successful time at school. I was dux of the prep school and I was dux of the senior school.
That’s an achievement! What turned you first on to science? Was it an inspiring teacher? Who did turn you on to science?
At the age of 13 or 14 an aunt gave me a Lott’s chemistry set as a birthday present. I started doing chemical experiments in the kitchen, until I finally stank everybody out. I was sent out to the garage, where I built a very nice little chemistry laboratory, and became very keen on chemistry. As my father was a chemist, I also had lots of books to read on chemistry. That was my best subject at school. We had a very interesting chemistry master in the last two years at Scotch College by the name of Jamieson. He was always called ‘Tort Jamison’ because he looked like a retort. He was tall and angular, with a rasping voice, and he was marvellous at teaching chemistry. I did very well with him.
Then, in mathematics in my final year, we had A.D. Ross as the mathematics master, who is no relation to the professor of physics in Perth. Ross was a very good mathematician and he had a first-class MA. But in those days there was no job for a research mathematician, so he taught at school. He was a remarkable maths teacher and he produced a string of people who eventually went into the Academy. For example, Alan Head, who was a year or two after me, was one of his students.
Alan Head was at CSIRO, wasn’t he?
Yes, that’s right and he’s an FRS. Richard Dalitz was in the year immediately after me, he was also an FRS, and there was Shaw in front. There was a whole string of first-class people, and it was because of Ross’s inspirational teaching in mathematics. I was really torn between mathematics and chemistry, as a result of having two outstanding schoolteachers.
So there wasn’t really a great emphasis on physics in those early days? It was mostly mathematics.
The physics master was a chap by the name of Kaye. We called him Teddy Kaye. He had a DSc, but he wasn’t a very great teacher. One of his big advantages was that he would let you do what you liked. So we would spend hours in the lab doing our own experiments, which was very good for us. In a sense, he was very good at self help.
Did you build any equipment at that stage?
What we were doing was trying to measure ‘J’, the mechanical equivalent of heat. We spent hours on it and got a pretty good result in the end. We had to build the apparatus for that.
After school, what then?
I went to the University of Melbourne. I wanted to get a job in the vacation after leaving school and before starting at the university. So I went along to the boy’s employment bureau. They gave us all an intelligence test. It was supposed to take an hour and I did mine in 10 minutes. Then I went to an interview with a chap. He had a great card index that he went through, looking at all the jobs. He said, ‘Not good enough for you. Not good enough for you. Not good enough for you’. He didn’t have a single job for me. So I had to work as a delivery boy for a chemist, riding a bicycle. I learned to ride no hands. It was marvellous.
Then I went to the university and to Ormond College. I went to sit for a £10 scholarship to Ormond and the master, D.K. Picken, who was a mathematician, wrote me a letter before calling me in. He said, ‘You’ve done so well that, instead of giving you £10, we’ll give you £80 as a full-time student.’ So I went into Ormond as a full-time student and I found it a very mixed place. I loved the master of college, but it was full of brutal students.
That was very much the case sometimes in those colleges at universities, at that stage.
That’s right. What fixed these brutal students was that, after the war, a lot of ex-commandos came back to the university and they were a bit too big to be pushed around.
Can we just go back for a moment? I really want to hear something more about that first year. Although you were not happy at Ormond, you had lectures from Cherry that you thoroughly enjoyed. Is that right?
Cherry was absolute bliss. I used to look at my watch through the lectures, hoping that he wouldn’t finish. He was so good. That made me love mathematics. But, in physics, Les Martin, who was a senior lecturer then, gave a very advanced course for first year physics. So I liked physics. Chemistry, I’m sad to say, was a disaster. Although I had come top of the state the previous year in chemistry, I flopped and only got a second class honour.
Was Laby still head of department then?
That’s right. Laby was still there for a few years afterwards.
Getting ready to enter the war
After one year there, what happened then?
The war had started by then. At the end of 1941 I wanted another job, and I didn’t want to be a chemist’s boy. I thought I would go into the Melbourne University Rifles and spend the three months vacation there. So I ‘enlisted’, if you can call it that. We were waiting on Spencer Street Station to catch the train on 7 December 1941 and the news came over the loud speaker that the Japanese had just bombed Pearl Harbor. All of a sudden, instead of being fun and games, it was real work. I was put in a platoon for three-inch mortars, which I learnt to fire, it was very good. We could put three bombs in the air at one time!
At the end of my three months there, I thought, ‘I don’t want to go on to the university. I want to enlist.’ I had had enough experience of the Army to say, ‘No, thanks,’ and I didn’t want to go into the Navy, so I thought, ‘I’ll go into the Air Force’. But they had reserved occupations and, if you were in a reserved occupation, you were not permitted to enlist – unless you could get approval. My father found an advertisement in the newspaper for ‘radio location’. It used to be known as RDF and later became radar. The advertisement was inviting science students to apply to the RAAF for radio location. I put in for that and found that the university, in the form of Professor Cherry and Professor Laby, would give me the approval to enlist for radar but not to go into aircrew. So I joined up as a trainee radar officer.
After you enlisted in the Air Force, what next?
I did a radio physics course at Sydney University. There were about 30 of us and we were called the ‘Bailey boys’ because the head of the physics department was Professor V.A. Bailey. He was a very good physicist but a very eccentric person. They set up a six month high-pressure course in radio. It was so good that in the end we were designing and building our own equipment. I built my own cathode-ray oscillograph and designed and built a push-pull amplifier. All after six months of training!
We also had to learn to solder. They had a man in the store who would approve of your work and he was a brute. With everything you took along, he would say, ‘Take it back and do it again.’ Eventually I became very good at soldering. This was very important when I went into the Air Force proper because I could show the airmen that I was as good as they were at soldering. After that, I went to radar school at Richmond RAAF base and trained in radar. Then I had a one-month course at Bradfield Park to be an officer. That was pretty awful because it was right in early summer. We were in tin huts – stinking hot – having boring lectures, and you had to drill the men. It was dreadful. But in the end I finished up as a pilot officer.
Around about that time, you met and married Barbara.
Barbara’s father was a Congregational minister. He went through Adelaide. He was a firstclass student. He did an MA with Sir William Mitchell, but he came to Melbourne as a Congregational minister. He had nine children and Barbara was the second youngest. So I met her when she was 12 years old and I was 14 – love at first sight! Then her father, Aubrey Stevens, moved to Sydney because he was a man who was affected by his calling. He didn’t like ministering in affluent areas. He liked to work in the slums. So in 1943 he left to go up to Sydney to work in Redfern and Waterloo, by which time I was in the Air Force. So I completely lost touch with her family and lost touch with her. But then, at the end of the war, by accident, I finished up in Sydney, met her again, got engaged and got married!
Perhaps this is an appropriate time to tell us about the family that you had with Barbara.
We had three children. The eldest is a boy, Angas John; the next is a girl, Elinor Mary; and the third is a girl, Rachel Louise. John went through Adelaide University and did an engineering degree. He then did a PhD at New South Wales in computing science and finished up in Monash as an associate professor in information technology and computing science. He was also chairman of the academic board there. So he has done quite well. Elinor got a first class degree in physics and went to Canberra to do her PhD in astronomy with the chap who later became the head of Mount Stromlo. She found that she didn’t like sitting in the dark, looking at stars, and she chucked her PhD and went into the public service as a computer programmer. She’s been there ever since.
Working where?
Here, in the state government. At present, she is stationed at the university here, doing some work in environmental type stuff. The third one, Rachel, became an architect. She lectures in architecture at the University of South Australia and has been on a number of Australia-wide committees pronouncing on Australian architecture and examining in various universities. She is married and has two children, girls; John had two boys; and Elinor never married.
I thoroughly enjoyed reading the notes that you gave me. One of the fascinating parts was your wartime experiences. Tell us something about those.
The Air Force, in its way, did some things which were absolutely unbelievable. Myself and another radar graduate, Bruce Aldridge, were both posted first to New Guinea to become commanding officers of a radar station on the D’Entrecasteaux islands. Bruce was just turning 19 and I was 19. So aged 19, I was in charge of 35 men. I had only just left school and done a radar course and was then stuck on this island miles out. The only communication with the rest of the world was a boat that used to come pretty sporadically – once a week or once a month sometimes. We battled on there, with a radar station perched on the top of a cliff.
One of our best results there was when we were sitting, looking at this radar screen, and suddenly we saw an echo come right up to the top. That meant that it was big. It just sat there, which meant that it was flying straight towards us. It turned out that it was a 100-bomber raid coming straight over us. We were able to give an hour’s warning and Bruce Aldridge, who was further up at Goodenough Island, also gave an hour’s warning. So, by the time these 100 bombers and the escorting zeros arrived at Milne Bay, half of the New Guinea Air Force was waiting to meet them.
Was it all 10-centimetre radar in those days?
Oh, no. Nothing like that. It was long range. The English had developed radar for the English circumstances and they had built these great towers, which would be hopeless for New Guinea. It was the Australians, under Les Martin, who developed the light-weight radar, which you could pack up, cart into the islands and erect there. They worked wonderfully. They used to have valves about this size (indicates), which would function very well at that frequency. I think that radar it was an enormous Australian achievement and it was absolutely ideally adapted to New Guinea. Whereas the British radar would have been hopeless and the Americans had no idea what day it was. In fact, they used to ask the Australians to help them.
What is so amazing for those days was being able to see the flotilla of aircraft coming towards you so early. That was so valuable. That was where radar really helped to win the war so well for us.
Yes. There was one occasion that didn’t work out so well. I got a note from fighter control saying, ‘The plot that you recorded as friendly has flown over Milne Bay dropping bombs and causing damage. Would you please explain?’ So I rushed down and had a look at the plot and saw that there were three plots heading towards Milne Bay and then three plots going into Milne Bay. The three plots heading for Milne Bay had ‘IFF’ on it which meant ‘identification friend or foe’ and that it was friendly aircraft. The three plots in Milne Bay didn’t have ‘IFF’. But it was well known that the airmen would turn it off when they were coming in to land. So what happened was that there was an allied aircraft coming this way (indicates) and a Japanese aircraft coming that way (indicates) and the paths crossed. The operator, quite naturally, thought it was a single track. We explained that to headquarters and they didn’t reply, so I presumed that it was all right. I found out later, from talking to other people, that it was not uncommon for radar tracks to get confused.
After the war, what then? What did you do immediately after the war?
My last posting was at 347 Radar Station on Manus Island. Although that was Australian territory, it was essentially an American base, so everything was paid for by Americans. We had American clothes, American food et cetera. Then suddenly, when the war ended, Lend-Lease was chopped off and the Australian government had to pay for us, which they didn’t want to do. Immediately all the RAAF on Manus Island were hauled out and sent back to Australia, and I was given the job of carting three radar stations from Manus Island back to Sydney. We went back on an aircraft carrier, HMS Slinger and I had a nice trip down from Manus Island to Sydney on the aircraft carrier. When I got to Sydney, I had to disband the three radar stations, and I popped out to see my father-in-law and I met Barbara. Romantic, wasn’t it?
Absolute magic. Very fortunate.
Then I came down to Melbourne and picked up my course again.
If I remember correctly, you did but a double degree. A BA BSc; is that right?
Yes. When I went to Ormond College, the master, D.K. Picken, said, ‘With your sort of interest, we’ve got the course that would suit you called a BA BSc.’ Mathematics in those days was a BA degree and physics was a BSc. So you would spend three years doing mathematics and physics and then another year to finish off the BSc degree with physics. The result was that I came out fully qualified in both mathematics and physics. It was a marvellous course. So many people have done it including Dalitz, Alan Head and lots of other people. It meant that we were turning out graduates who were really very well trained in physics and mathematics.
Before you went to the war, in your first year at university, you had Tom Cherry as a lecturer and you found him very inspirational. Did you have him again when you returned to university?
Yes. We had him in second and third year, and he was very good. We also had a chap by the name of Bert Corben. His wife, Mulaika Corben, wrote a book called Not to mention the kangaroo, which was a very severe attack on Melbourne University and all the ningnogs there. Bert Corben left after one term to work with Oppenheimer and so Cherry took over. They were very good. Physics was pretty spotty then. Second-year physics was pretty off-putting. Third-year physics was good again.
Did you get a scholarship to go overseas at the end of your degree?
That was a bit of a swizz because I got a scholarship called the Aitchison Travelling Scholarship. It was the top scholarship for Melbourne University. It was worth £A350 a year, which I thought was going to be pretty good. But, when you converted it into Sterling, it came down to £280 a year and my fees at Trinity and my rent came to £200. So I was living on £80 a year. I got by because I had saved up £700 in radar. Being stuck on islands, you couldn’t spend any money and so I had saved a lot of money. Essentially I paid for myself until the second year. Oliphant had told my father that the ANU was opening up scholarships. So I applied for a scholarship at ANU and got it. All of a sudden, I got £600 Sterling a year and we were very comfortable.
What a difference.
We had a nice house with some spare rooms. We let two of the rooms and we had a number of students. The third student we had was a man by the name of Tony Jay, who later came to write the television programs Yes, Minister and Yes, Prime Minister. And we knew him as a student! He later became Sir Anthony Jay. So that was very interesting.
At that time, didn’t you get some advice from Dalitz which was contrary to what you actually did?
He had come to Cambridge. He had had an Aitchison Scholarship and also had found himself absolutely strapped, as far as money was concerned. He had to leave after a couple of years. He went to Bristol. He had a pretty low opinion of British physics and said that the only place where real physics was being done was the United States and I should go there. But with my family tradition, I had to go to Cambridge. As it turned out, it was the right thing to do.
Where did you meet Dalitz and how did you know him?
Dalitz was a year after me at school, at Scotch. Then, when I came back after the war, at the beginning of my second year, I was going to tutorials in Ormond and he tutored me in mathematics for one term. So we kept in touch with each other almost up to the end. He died some years ago.
Tell us about the Cambridge years.
Once we had got our finances settled, it was much nicer. The staff there were not really much help. My first supervisor was a chap by the name of Eliezer who left after one term. So I was left without any supervisor at all. I fossicked around and found my own problem, which I worked on. But for a lot of time I was talking to other students. A fellow student of mine by the name of Abdus Salam, whom I knew very well, later on got a Nobel Prize. PT Matthews also did very well, he became an FRS. I also spoke to Roy Chisholm and Behram Kurşunoğlu. We had some very good students there. Then there was Dirac, and Dirac was a marvellous experience.
Do I take it then that the students who were with you were doing original research and getting it published?
I could go into the whole story of what was the question of fundamental physics then. But, as students, Salam and Matthews, with John Ward working independently at Oxford, laid the foundations for a rigorous approach to it. The Americans had given up on it. It wasn’t their supervisors but the students who did it all. The supervisors weren’t able to keep it up with it.
PhD work in lay language, please!
Can you tell us something about the work that you were doing at that time – in lay language, if you can?
I picked my own problem at the end of the first year and worked on that for the remaining two years of my PhD. Fundamental physics had got to a very interesting stage then. The only way you could treat fundamental physics, as the equations were so complicated, was to use what is called successive approximations. You would start off with a picture in which there was nothing happening, so-called ‘free field’. Then you would add little corrections, due to the fact that there were some interactions taking place. You would have to calculate these one after the other. It is what is called ‘perturbation theory’.
The remarkable thing about it was that when you made your first correction, you got some very good agreement with experimental results, so it looked as though you were on the right track. However when you did the second correction, it blew up completely – infinity and, from then on, infinity. So a major achievement after the war, by Sin-itiro Tomonaga from Japan and Julian Schwinger and Richard Feynman from the United States, was to find a way to handle these things. They constructed a procedure called renormalisation theory, which enabled one to extract sensible results from all these absurd calculations.
I know that term so well, but I have no idea what it means. What does ‘renormalisation theory’ mean? Is it possible to explain in simple terms?
As an analogy, when a boat goes through water, it drags the water along with it. Therefore, the actual weight of the boat increases because of the dragging along of the water. The same thing happens with charged particles. They have an electromagnetic field around them which they drag along as well, and that increases their mass. Unfortunately, because they are particles, the whole thing is mathematically ill-defined and it is this additional mass that becomes infinite. We know that electrons do not have infinite mass, therefore we would say, ‘Although it must drag it along, as water is dragged along by a boat, it does not drag it to infinity.’ So they rephrase it so that it comes back to the sensible experimental result, which you put in by hand. You can’t calculate it. That’s called ‘renormalisation’.
That’s a great thing for me to know, because I have never known what that phrase meant.
I would say it became marvellously effective. You could get up to 10-decimal-places accuracy with it. Nevertheless one didn’t know whether carrying out the succession of approximations would work. So I gave myself the job of trying to show that they did – ha, ha! It was a pretty ferocious project, but I showed that it doesn’t work.
A moment ago, you mentioned Dirac. How did you come across Dirac and was he a good lecturer?
He was a marvellous lecturer. In Peter Szekeres’ account of Dirac’s visit here, he said that Dirac would stop, say a complete sentence without any ers or ums, stop again and say another complete sentence. You could write it down and get a perfect account. It was marvellous to listen to him. But he had a very simple approach. We were a bit contemptuous of him, because he didn’t know anything about modern physics. He used to sit there and usually go to sleep. One of the tests, when you were giving a seminar, was to see whether you could keep Dirac awake. I always succeeded and I was very proud of that. When he asked questions, they were always so simple that you realised what was going on. When he lectured, it was all so straightforward. You weren’t being blinded with science, but you found that what he was saying was so profound – simple but profound. He was an absolute pleasure to listen to.
He was a very withdrawn sort of person. One of my finest achievements was that he invited me to his place for afternoon tea. I went along and had tea with him, his wife, who was Wigner’s sister and very bossy, and his daughter, Margaret, who was 12 or 13 at the time and also very bossy. So there was this great man being bossed around by these two women.
What age would he have been then?
He was born in 1902 and this was 1951, so he would have been 49 or 50.
To have these little sketches of people with very famous names is great.
Despite all his ignorance of modern physics, he would get up and give a seminar which was years ahead of its time. The things that he talked to us about then are still very strong. All the marvellous things that we talked about have all been forgotten.
You were involved in the Delta Squared V club, weren’t you?
Delta Squared V was a sort of theoretical science club. First of all I got the job of being the treasurer. The next year, I was the secretary. In the third year, I would have been the president, but I had left by then, so I never became president. But, as secretary, I had a major job – I had to find the speakers – and I did wonders. One of the speakers I got was John Littleton, who talked about the theory of comets. Another one was John Pople, who had just got a Nobel Prize on the nature of water. The third one was William Cochrane, who did some marvellous work on X-ray crystallography. So I got these three speakers. But I also had to write an account of what they had said. Well, I couldn’t understand what they were saying! Fortunately, I was able to get hold of some subsidiary information either from writings or by talking to other people. So I was able to write the accounts, which I would then show to the speaker. They all thought I did a good job, which was really a fake.
So that was that. Being the treasurer I had the job of sailing into people who weren’t up to date with their subscriptions. If they weren’t up to date, I would beat them out. So it was really quite a nice job!
Maths with Cherry to physics with Green
After Cambridge, what then?
As I was finishing up my PhD – which was a bit of a job because it was all my own idea – I got a letter from Cherry offering me a job as senior lecturer in the mathematics department in Melbourne.
So you were pretty young?
It was 1952 and I was 29.
Twenty-nine is still young for a senior lectureship.
Yes. I got a write-up in the paper about ‘these young people who are being appointed’, but at that time I was suffering from alopecia and I had all these white spots over my head. They said, ‘We don’t have any grey-headed people around,’ and I had all these white spots all over my head. Anyway, I went back to Melbourne, and that was a plus and a minus. I loved being back there and I liked the people in the department – Cherry, Love, Behrendt and Schwerdtfegher. They were first class.
This was in mathematics and not physics.
That is right, in mathematics. But I used to go across to physics to have afternoon tea and keep in touch with them. Les Martin was the professor there. So I kept my contact up with physics. But there was no one there who knew anything about modern particle physics, so I went into a slump and didn’t publish anything. There was one place where I could have published something. Freeman Dyson wrote an article called ‘Missed opportunities’, and I could have written an article about missed opportunities then too. There was a problem that was staring me in the face that I completely missed and other people picked it up afterwards. So I was getting a bit desperate. Then Bert Green, who was here by then, offered me a job. He hadn’t had much success with his two previous appointees. So I jumped at it and came over to physics in 1957, and I stayed here until I retired.
Did you know him before he asked you to join him?
I had seen him at a meeting in Canberra and I knew of him by reputation because of the world famous BBGKY (Born-Bogoliubov-Green-Kirkwood-Yvon) theory of dense liquids. Bert was famous for that. But Bert was always regarded as a little bit off mark because he was very original and he always wanted to follow his own ideas. People were not always quite sure about Bert. They found out that a lot of the things that he was saying were right – but not at the time.
He was a very clever man.
Yes. He was a genius. I told a story about him at his memorial service, which I think was wonderful. I was writing a paper with Bert and Yehiel Ilamed. Bert wrote the paper, of course, so I was checking it through and I came to something that I couldn’t understand. I thought, ‘As I’m a co-author, I should understand everything that’s in the paper.’ So I spent a week working out what this particular equation meant. I went and showed it to Bert and he nodded and nodded. A while later, I was sitting in my office and he came in and said, ‘I’ve managed to improve on your calculation.’ Then I realised that he had never done it! He had just guessed it and it wasn’t until I had done it that he had found a proper argument for it. So that is what you were dealing with. That is what a genius is. As Immanuel Kant said, ‘A smart person is someone who does something and, if you work hard enough and think hard enough, you can understand it; a genius is somebody who does something that you’ll never understand’ – and Bert was like that.
Pfaffing around with the Ising model
If I remember correctly, you collaborated with Bert Green in those early years on the Ising model. Can you tell us something about the Ising model – again in lay terms, please?
It is a very famous model. It is a simple model of magnetism, in which you have an array of little magnets that form a rectangular array. The little magnets can only point up or point down. The chance of them changing their direction from up to down will depend on two things. One is what the magnets nearby are doing – that is the interaction – and the other is the temperature that makes them jiggle around. So the question was to study this model mathematically. This is done by ‘statistical mechanics’. In 1943, Lars Onsager found a way of solving the problem by using very abstruse algebra. I remember him giving a talk about it in Cambridge and no one understood a word of what he said. He used to stand with his nose to the blackboard and mumble, so it was pretty hard to follow him. John Ward, who had been in Adelaide and had gone back to the United States, was working with Mark Kacs and they thought they should simplify Onsager’s work. They found a way, more or less by guesswork, of replacing Onsager’s abstruse algebraic calculations with little pictures. I read this paper, found that their little picture could be improved and told Bert about it. He said, ‘That’s very interesting,’ and he came back with a paper ‘Hurst and Green’, in which he worked out all the mathematics, introducing a concept that I had told him about before called ‘pfaffians’.
What are pfaffians?
Pfaffians are named after a German mathematician, Pfaff, and they are a mathematical structure. You know what determinants are (a value associated with a square matrix). If you have an antisymmetric determinant of even order, it is a perfect square. A pfaffian is the square root of an even order skew-symmetric determinant – if that’s any help.
I did ask! That’s great, thank you.
We found that it reduced the Ising model of Onsager’s calculation to a very straightforward thing. Later on I found that you could extend it to an infinite set of different models. We found that they all came out as one part of this single construction, using pfaffians.
Quite an achievement.
Then, from talking to a mathematician in Toronto, I discovered that the best way to describe pfaffians was to use what are called Dirac algebras. That reduced the thing from Onsager’s enormous calculation to a third-year subject. So I am very pleased about that.
My trouble is that I tend to lose interest in something and not keep digging down the same ditch. When the Australian Research Grants Committee (ARGC) came in, I asked if I could have a visit from an American mathematician by the name of ‘Slim’ Sherman. He had done some mathematical work in the Ising model area. He was called ‘Slim’ Sherman because he was six-foot-four and about 17 or 18 stone, and he was a lovely person. He came out and for six months we worked together. We extended his arguments about Ising models in two, three or four dimensions – any number of dimensions – to general mathematical statements and we produced some mathematical structures called ‘inequalities’. To give us a bit of advice, we called in another mathematician, who had been prominent in this area, by the name of Griffiths, who was at Carnegie Mellon University. We wrote a paper which is called the ‘Griffiths-Hurst-Sherman inequalities – GHS’. That is one way my name has gone down in history – as GHS. So that is the Ising model – never been back since.
Putting physics on a solid foundation
What is the work of which you are most proud?
It all started back in 1958 or 1959. I was reviewing articles for mathematical reviews and I had reviewed a paper by a chap by the name of Candelin. He was tackling one of the continuing problems in quantum electrodynamics – ‘supplementary condition’, which seemed to be misbehaving for different reasons from the divergences. He had a way of handling it. But, I thought it could be expressed much better if one used algebraic methods. So I wrote a paper on this and then, when I went to Britain in 1961 on my first study leave, I took this account with me. I talked about it in Edinburgh, and they loved it. I talked about it in Glasgow, and they loved it. I talked about it in Cambridge and even kept Dirac awake. In fact, two students told me afterwards that my talk had inspired them to go on in mathematical physics. Then I went down to London, to Salam’s group, and they hated it and they were very nasty. They said that it was too mathematical. Later I went to Geneva and they hated it too. They said that it wasn’t mathematical enough! I thought, ‘Oh, blow you,’ and just left it.
I kept getting a bit niggled by it and about eight years later I thought, ‘We should be able to do something with this’. In the way of a most cruel lecturer, I gave it as a PhD topic to my student Janice Gaffney. She cottoned on to the key approach. She wrote it up and got her PhD for it. We then sent it off to be published and it was rejected. We were a bit stunned.
We had a postdoctoral student with us at the time by the name of Alan Carey, who is now a professor in Canberra. He came in and said, ‘I think we can do something with your problem,’ and it was very subtle. We had used algebraic methods. One of the algebraic methods that we had used was called ‘von Neumann algebras’ and Alan Carey suggested another algebraic method called C-star algebras, and that worked beautifully. So we published it with no trouble at all. We then dug away regularly and rebuilt the whole structure of the supplementary condition in quantum electrodynamics using this approach.
Then another student came along, Hendrik Grundling. Interestingly enough, Hendrik was a South African who came to Melbourne because his cousin had started to pay for his study as an MSc. So Hendrik came to me to do an MSc and I put him on to this problem. He turned out to be a very good mathematician who is now at the University of New South Wales. We took up ideas that Dirac had talked to us about back in 1950 and rebuilt them to make a proper mathematical theory: the Dirac Theory of Constraints. I lectured on that in a Schladming conference and got written up in the local newspaper. I am very proud of it because it provides a foundation for what are called ‘constrained physical theories’, which are theories in which there are constraints where things cannot vary freely. They are called ‘gauge theories’ in physics. The whole of physics is built with this, and we have the rigorous basis for it. It is not new particles and it is not new laws of physics, but it puts things on a solid foundation. I am very proud of that.
Yes, indeed.
In 1961, Adelaide had instituted a study leave program and you went on your first study leave to Edinburgh. Can you tell us something about that study leave and also about subsequent study leaves?
The only people who could go on leave were the professors. The sub-professorial staff could only go on leave if they could find someone to take their place and pay their salary. The result was that sub-professorial staff could not go on leave. We had a marvellous vice-chancellor here by the name of A.P. Rowe and he invented the ‘study leave program’. So, when I came here, I got on to that program. Not only could you go on leave but you were also paid £300 and a per diem. So all of a sudden I was able to take my family. We came over by ship and we went back by ship. In fact, coming over by ship, I sat down and read four volumes of the History of the Decline and Fall of the Roman Empire. That is the beauty of sea travel.
Who did you go to in Edinburgh?
Nick Kemmer, who had been in Cambridge. He was a very good scientist, but he had essentially given up doing research. The previous professor was Max Born and Nick Kemmer took over, so I went over and spent a year there with them. I actually shared an office with a chap by the name of Peter Higgs. Peter Higgs was chugging away most of the time trying to organise ‘ban the bomb’ marches and things like that. Every now and then I would get run up by the police: ‘Police here; can you give us some information on the ‘ban the bomb’ march?’, and I would say, ‘Wait until Dr Higgs comes in.’ He went on study leave two or three years later and wrote a paper. In that paper he invented what is called the ‘Higgs boson’. They have now just built a $10 billion machine to look for the Higgs boson that he predicted in 1964.
They are still looking for the Higgs boson, aren’t they, using that extremely expensive accelerator in Switzerland?
They still say ‘next year’. If they don’t find it, it will be a real puzzle and the whole of physics will be tipped upside down. People are very anxious. If they can’t find it, what on earth do you do next? The Higgs boson is the origin of all mass. Without the Higgs boson, where does all this [indicates] come from?
After Edinburgh, when you returned home, what then?
I came back to Adelaide. Then I had a good trip to Toronto in 1964. I stayed at a place called Massey College, which was a student college for senior people. Massey was named after the Governor-General of Canada. The room I had was one that was normally occupied by his brother, Raymond Massey, the well-known film star. So I had the film star’s room, which was very nice. It was a very comfortable college and the master was Robertson Davies, who was a very famous Canadian novelist. He was a very attractive person and he had an Australian wife. So that was very good. The mathematics department had some very good people. One of the best known was H.S.M. (Donald) Coxeter, who was a very good algebraist and has become famous because of all the drawings of Escher. The mathematician who advised Escher, was Coxeter, and he was at Toronto. Coxeter was a nice bloke to talk to. So I enjoyed Toronto very much.
Later on, in 1967, I went to Miami on study leave with Behram Kurşunoğlu, who was a Turk who had been a fellow student in Cambridge with me. Being an Australian, I got on very well with him. We always argued about Gallipoli. One of his favourite stories was that the Turks had invented poison gas: they used to throw their socks over! He started up the Coral Gables conferences. At the first one I went to, when I came to the door, J. Robert Oppenheimer came up and shook hands with me. I met Onsager and Gellman as well as Robert Oppenheimer. All the great people were there. Coral Gables was very nice indeed.
Geographically, where was that?
It is in Miami. There’s a suburb of Miami called Coral Gables – very upmarket.
Was it a series of conferences or just that one-off?
They had them every year. I came back to Miami again with my family a couple of years later. That was another Coral Gables conference and I was one of the editors of the proceedings.
Are there other study leaves of note?
In 1974, after I had been on council at Adelaide University, I wanted to go on study leave. I thought I would go to Indiana and meet up with ‘Slim’ Sherman again. He invited me over but, unfortunately, he died of cancer before I got there. I spent a year at Indiana University, which was a marvellous university, and again met some very good people there. It was cold as billyo – down to two degrees Fahrenheit.
What year was this, by the way?
1978.
There are still a few study leaves to go then.
Yes, that’s right. I had a big tour in 1981. I represented the Academy at a United Nations thing. I went down to Marseillaise and across to Vienna. In fact, I have been to Vienna about six times. I know Vienna very well. The professor there is a chap by the name of Walter Thirring. He and I worked in the same area and got on very well, so he used to invite me to come to Vienna. I went and spent several months there. It is a beautiful city – and the opera house! We used to love going to the opera. The Palace of Schoenbrunn – gorgeous.
I also want to talk to you about the things that were going on in Adelaide at that time. One of the things that you were heavily involved with was the Goolwa conference. Can you tell us something about that?
Gellman came to the Coral Gables meeting and I knew that he was keen on birds. So I thought that the best way to get him to come to Australia was to say, ‘Have you ever seen kookaburras?’ He said ‘I’d love to see a kookaburra.’ So, when the time came for the conference at Goolwa, I rang him up and he said, ‘I’d love to come out.’ He came out and I thought, ‘I’d better show him some birds’. I asked Ian John here, ‘How can I show him some birds?’ and he said, ‘Go out to the salt pans.’ I got permission to go out at seven am with Gellman to look at the birds, and we sat there. He knew every bird by name. I don’t know one bird from another, really. He was very grateful.
After that, we went down to Goolwa. On the way down, I was talking to him about walking in the bush. I said, ‘In Australia, walking in the bush isn’t much trouble because there are no big animals to be frightened of. In the United States you have got to look out for bears and mountain lions.’ He said, ‘I don’t worry about that.’ I said, ‘The only thing we’ve got to worry about is snakes.’ Well that scared him! He was frightened stiff! I said, ‘You just watch out where you put your feet and don’t stick your hand up a hollow log.’ But he was terrified of snakes, so I won that one.
Being a great bird watcher, Gellman hated birds to be caged. Bert and I took him to the big aviary at Cleland. I could see that he was getting very restless and didn’t want to go there. But Bert just charged ahead, so we had to follow. We came into this big walk-through aviary and Gellman put his hand over his head and ran through. He wouldn’t look. He couldn’t bear to see caged birds.
At that conference, you made a contribution and I understand from what you have told me that it went down like a lead balloon. What was the sequel to that?
Previously, Schwinger had given a marvellous collection of talks on the foundations of quantum field theory and, in particular, the concept of magnetic charge. Dirac had invented the magnetic charge back in 1931 and it had sat there. Schwinger got very keen on the idea and started talking about it again. I got interested in this and found that there was another way of looking at it, different from Dirac’s and different from Schwinger’s. So I wrote up a paper, which was published very easily in the Annals of Physics. I talked about it at Coral Gables. It was the first time I had ever spoken at an international conference – and there was dead silence. I went away with my face down near my feet. I refused to go to the next day’s meeting and I refused to go to the summing up. They came back and said, ‘The person summing up’ – Nicolai Cabibbo – ‘spent 10 or 15 minutes talking about your paper.’ And I wasn’t there!
Serves you right [laughs].
It is still going. I got buckets and buckets of citations on that one paper.
In addition to your visits overseas, a number of important people came as visitors to the Department of Mathematical Physics in Adelaide, didn’t they? Can you tell us something about them?
Dirac came to visit Oliphant, when he was there. Then we had a string of other people. ‘Slim’ Sherman I have mentioned. There was Arthur Wightman, who was a leading mathematical physicist. Jim McGuire.
Tell us about Jim Maguire.
He was at Boca Raton, Florida, Atlantic University, up north of Miami. I bumped into him, he got talking to me and he came. He and his wife came out on an ARGC. His wife was a very good swimmer, I remember. He and I worked together on one-dimensional problems, which were quite interesting. We got on well together. But, since then, he has got involved with Murray Bachelor in Canberra and Colin Thompson. So I haven’t seen him for years.
Are there others whom you would like to mention?
Milan Vujicic from Yugoslavia. His wife, a lovely person, was from Sarajevo, and they had two boys. They were lovely people. As a result, when we went over to Europe, I got an invitation to talk at Belgrade. I was giving a seminar and, in the middle, one of the audience got up and walked out. I asked, ‘What’s wrong with him?’ Milan said, ‘He couldn’t understand your English.’ That taught me a lesson. From then on, whenever I talked in foreign countries, I talked very slowly. I can talk in Poland, Yugoslavia, everywhere and they all understand me. That was from my visit to Belgrade.
Oh, and I nearly got thrown into jail. I was very keen on steam trains. I love steam engines. I have got a whole shelf full of photos of steam engines. Milan Vujicic was taking us for a drive in the country and I saw a steam engine puffing away. I said, ‘Stop the car.’ We stopped and I jumped out, got my camera, rushed over and took a picture of this steam engine. As I was doing that, a great big Yugoslavian came across, ‘Rrr, rrr, rrr,’ and grabbed hold of me. I was going to be thrown into jail. Milan Vujicic got a policeman to come along and I explained to the policeman that I was a stupid Australian professor who loved steam engines. He gave me my camera back and didn’t even take the film out. Apparently when I took the photo of the steam engine, I turned my back on a military airport, which I didn’t know was there.
On the roll of film there was also a picture of a high-rise apartment that had caught fire. It was a high-rise apartment that had been built in honour of Tito. It had caught fire and they thought it was sabotage. I thought, ‘If they had found that photo, I’d have got plonked into jail.’ All the time this fellow was holding on to me, I kept saying, ‘I’ve got a book about Yugoslavian trains. I know all about them.’ When I got back to Australia and looked up the book, I found, ‘Taking pictures in Yugoslavia is terrible. I got arrested three times’ – I was lucky. I loved Yugoslavia then, but I don’t now.
Students and inter-departmental collaborations
In addition to the piece of work that you told us about earlier, are there other pieces of your work that you are particularly proud of?
I tended to put all the problems to my students rather than to work on them myself. I had some very good students. People worked on the Ising model and also with a lot of algebraic work. Another was upper-air meteors – Logan Francey, one of my students, worked on that. And there was underwater submarine detection. I got involved with quite a lot of people – bits and pieces. I would pick up things.
You and Bert were perhaps unusual in that you both had a wide range of interests in mathematical and theoretical physics. Although you didn’t collaborate much with him, did you?
No, not until later on. We did a little bit of work on algebra, but then he worked with Tony Bracken and Terry Triffitt rather than with me. I went my own way.
You had some very distinguished students, didn’t you? Can you mention some of those?
Do you remember Henry Tuckwell? He worked with Alastair Blake.
No.
They went over to the United States. He was very good. Logan Francey, I’ve also remembered. Bob Irvine was very good. He died some years later. He did a computer study of the Ising model. That was something. In those days they used punch cards.
I had a friend at Adelaide University by the name of David Kerr who was in physiology. I got talking to him at a New Year’s Eve party about some work that he had done on nerve membranes. He referred to a little letter that he and some other people had written about Easter time. I went home and found that you could rephrase the whole thing in terms of what was called a ‘master equation’. So we developed a computer program for the master equation in which you could replicate a nerve membrane as an array of sites which were either open or closed and they would correspond to potassium or sodium irons going through pores in the nerve membrane. The question of whether they were open or closed would depend on what the labels were doing and what the temperature was. We worked out the statistical mechanics of that and did a computer program on it. We found that we could improve on Hodgkin-Huxley’s graph of the variation of the current through the nerve membrane with temperature. In fact, they even thought it had some relation to the blue ringed octopus. We wrote a couple of papers on the nerve membranes.
David Kerr worked in the Darling Building, didn’t he, just nearby?
That’s right. That was a bit of extensive computer programming, which worked very nicely.
You are a Fellow of the Australian Institute of Physics and of the Australian Mathematical Society and you have been elected a Fellow of the Australian Academy of Science. Can you tell us something about your involvement in Academy affairs?
I was on Council. I was also Chairman of the National Committee for Physics. The President of the Academy at that time was David Curtis and he got the idea that every national committee should write a report on what they were doing. I chased up physics all over Australia and wrote this report on the state of physics in Australia. It turned out that all the other committees were much smarter than me: they didn’t do anything. I busted my guts doing this.
In 1981, I came over to Edinburgh on study leave and then went to France to a meeting of the International Union of Pure and Applied Physics (IUPAP) as the Australian representative. I went along to talk to the United Nations Australian representative. He was very helpful. I wanted to set up an international conference for people from disadvantaged countries, like Sri Lanka and Bangladesh. So we ran this international mathematical physics meeting here in Adelaide. It went down very well. That (the publication arising from it) was an Academy proceeding and it got published. I raised about $5,000 to pay for it. That was very good, as we were able to pay the fares of a lot of people coming from these disadvantaged countries. We got some very good speakers to come along as well.
Did you have other involvement in international physics?
I was on the International Commission on Mathematical Physics. I more or less invented that. I went along and told IUPAP why mathematical physics should have a separate representation. So they formed the international committee and I was on that. I was quite involved with international affairs at that time and knew the people quite well.
Your time in Adelaide was a very important time of your career. Apart from what you did in the Department of Mathematical Physics, what was your involvement in university affairs generally?
I had been chugging along quite quietly until Lloyd Cox came along to see me. He was professor of the medical faculty. I am not quite sure now what his field was. Anyway, he asked me whether I would take over the job of chairman of the education committee. John Carver was the next one and I succeeded John Carver. The committee at that time had 125 people on it. It was said that it was slightly bigger than the United Nations. The meetings used to go on until after six o’clock at night. They would burble on and on and on. So, when I became chairman of the education committee, I decided to rewrite the whole university committee structure and also reorganise the running of the education committee. The simplest change was that meetings couldn’t go past half past four without a majority vote, and that stopped them in their tracks. Then I rebuilt the whole committee structure. Committees were sprouting up all over the place – some were council committees and some were faculty committees – and I tidied them all up. Now, everything has become much more executive than it was.
You were on council, were you not?
Yes.
For how many years?
Four years. I had some good arguments there. I remember that Dean Brown – he became Premier of South Australia – got up and gave a talk on something. When he had finished, I said, ‘You got it completely wrong,’ and I made him do it all over again. I was quite proud of that.
The other thing which took a lot of your time and interest in those years was the rebuilding of the university union. You were chairman, I think, of the union’s house committee. Is that so?
Yes. The warden of the union asked me to go on to the house committee. It was a pretty low-key job, just a matter of what you might call a general sense of responsibility. But that meant that I was on the union council as a member of the house committee. In those days, they used to put in submissions to the AUC. They put in a submission to the AUC for extending the building. The university was growing and the union was getting too small. The suggestion was that they dig a hole in front of the union building and, as an extension, put some rooms half below ground. The chairman of the AUC was Les Martin and he said that was rubbish.
What year are we talking about, by the way?
It would have been in the late 1960s. I said to Harry Medlin, who was on the committee, ‘What the union needs is a planning committee to make proper submissions to the AUC.’ So he put that up to the council with the recommendation that I be the chairman. So I was the chairman of the first planning committee, and our job was to oversee the extension to the union building.
That was a big job.
It certainly was. Henry Basten was the vice-chancellor, and I went to see him. He said to me, ‘We will let you have the services of the university architect, Ron Mutton, to get an opinion on what you should do.’ Ron Mutton came up with a plan for the extension of the union which really wasn’t very suitable, but it gave us the idea that it was possible. This planning committee was a very good committee, and one of its members was Jim Warburton. He said, ‘I had a very good architect building my house. Would you like to ask him? He’s a chap by the name of Dickson of a firm called Dickson and Platten.’ So we got them in to talk to them about it. At first I thought, ‘It’s too big for them.’ But they took on the job and they did marvels. The union building has been cited over and over again as one of the top pieces of architecture. That was Dickson and Platten’s work.
To pay for it was a problem. We got the maximum amount of money that we could out of the AUC, but it wasn’t nearly enough. The Adelaide University Council wasn’t very helpful. But we discovered that students had to pay a union fee and the union fee was paid by the government. So we could keep raising the union fee, which the government would pay. We increased our income, and by taking out a loan as well, were able to pay for the union building to the cost of $2½ million. In those days it was a lot of money, paid for by the federal government. It was very clever.
Very clever. Good thinking.
So I feel that is one of my greatest achievements – getting involved with that.
When we met yesterday, I noticed on the wall a very handsome coloured picture of you in university robes. What was the occasion on which that photograph was taken?
That was when I was pro-vice-chancellor. When I first got involved with things, the vice-chancellor was Geoff Badger and he retired. I was involved in the committee that had to choose a successor and they chose Don Stranks to come along. Don worked very hard, but he found it a bit stressful. Apparently, after one council meeting when he had had a bit of a hammering, he went along to Memorial Drive to play tennis and dropped dead. All of a sudden, there was no vice-chancellor. But, in the meantime, we had had some deputy vice-chancellors, but they weren’t all that popular. People tend to think of deputy vice-chancellors as a bit bossy. We had a committee about it and, in it, I suggested that we should try the idea of having a pro-vice-chancellor who would maintain an academic link. In a sense, they were more part time. They took that up and invited Kevin Marjoribanks to be the first pro-vice-chancellor and me to be the second pro-vice-chancellor. We were there under Don Stranks. When he dropped dead Kevin got the job of taking over – I was glad that I was second and not first. Kevin did such a good job that he was made vice-chancellor.
Did you remain pro-vice-chancellor?
I remained pro-vice-chancellor for two or three years. I found myself as a sort of universal healer. I would go around and listen to people and talk to them. I always found Roma Mitchell, who was the chancellor, an enormous help. She was full of common sense. I would turn to her for advice.
Yes, she was a remarkable woman, wasn’t she?
Oh, she was an amazing woman. She was a fellow student of my aunt. My aunt did law. She and my aunt and John Bray did law back in 1930-something.
Thank you, Angas. That was a really fascinating interview. I’m extremely grateful both for yesterday morning and for our interview today. I thoroughly enjoyed this long conversation with you.
Thank you for talking to me. It was lovely talking to you again, Bob.
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