Professor Robin Stokes, chemist

Professor Robin Stokes. Interview sponsored by the University of New England.

Robert (Robin) Stokes was born in England in 1918 and moved to New Zealand at age five. Stokes earned a BSc (1938), MSc (1940) and DSc (1949) from the Auckland University College and a PhD (1950) from the University of Cambridge. During the war (1941-45) Stokes worked as a chemist and chief chemist at the Colonial Ammunition Company, New Zealand. He then moved to Australia to take up a position as lecturer in Chemistry at the University of Western Australia. In 1948 Stokes went to the University of Cambridge as an Imperial Chemical Industries fellow. From 1950 to 1955, he was senior lecturer and reader in chemistry at the University of Western Australia. In 1955 Stokes definitive book Electrolyte Solutions, which he co-authored with Professor Robert Robinson, was first published. Also in 1955, he moved to the University of New England, as the foundation professor of chemistry, a position which he held until his retirement in 1979. Stokes was made emeritus professor from 1980.

Interviewed by Professor Ken Marsh 23 April 2009



My name is Ken Marsh. I started my research with Robin Stokes in 1961, completing my masters and PhD under his supervision and then accepted a lectureship at the University of New England in 1966. In 1983 I moved to Texas A&M University to be Director of the Thermodynamics Research Centre. I retired from that position in 1997, moved to the University of Canterbury and retired from there in 2006. I have been editor of the American Chemical Society’s Journal of Chemical & Engineering Data since 1991. While at the University of New England, Robin and I developed many new techniques for the measurement of the thermodynamic properties of fluids and fluid mixtures.

A family of scientists and childhood memories

Robin, I always thought that you were a New Zealander, but I understand now that you were born in England.

I was born in Southsea, England. Not that I ever lived in Southsea, but my mother happened to be there at the time, waiting for my father to be demobilised from the army after the First World War. In my family, people tend to get born in rather unusual places. My mother was born in the Lofoten Islands, which are inside the Arctic Circle, off the coast of Norway. The reason for this was that her mother happened to be there at the time; she was accompanying her husband, who was a chemist in a whale oil factory. On the way home, incidentally, she was shipwrecked, but it didn’t seem to cause any great problems and she was back in England safely in time to grow up.

I understand that, on your father’s side, you are related to Sir George Stokes of viscosity fame and President of the Royal Society.

My father was John Whitley Gabriel Stokes and he was named partly after Sir George Gabriel Stokes. The names John and Whitley are also standard names in the Anglo-Irish family that they have belonged to since the 1680s or so. If you look through the family tree, there were Johns and Whitleys and Gabriels everywhere.

I also understand you are related to the famous Irish surgeon William Stokes.

He was the man after whom the Cheyne-Stokes breathing is named. This is the erratic sort of breathing you get just before you die. So it is an interesting thing to have in your background.

I understand also that your father and mother’s families were involved in science and engineering.

On my father’s side, there were numerous mathematicians, physicists, surveyors and so on, mostly in Trinity College Dublin. On my mother’s side, I know for two generations before her they were industrial chemists. One of my mother’s forebears—it was either her father or her grandfather - was working in one of Nobel’s early dynamite factories and got blown up and lost an eye in the process. That is the nearest anybody in my family ever came to a Nobel Prize!

What about your father?

He was brought up in the English branch of the family. They had moved back to England and he was born in Herefordshire and had a typical English upbringing of public school. Then he went to Cambridge and did a degree in civil engineering and for most of his life he was surveying railways in one country or another—in Spain and in Argentina and later on, in New Zealand. He met my mother in Argentina, where he was surveying railways and she was accompanying her parents with some of their business interests there.

Then you moved to New Zealand.

Yes, I was only four or five when we left and I can remember little bits about the trip. I can distinctly remember the passage through the Panama Canal. The trip used to take about six weeks by sea in those days and I can also remember stopping at Pitcairn Island, which was a regular stop on the way across the Pacific, and being sold local trinkets by the inhabitants. But, apart from that, I don’t really remember much about the trip and very little about my early life in England. Except one memory, of falling down the stairs, bump, bump, bump, and the agony of wondering if you’ll ever get to the bottom, which is something that doesn’t happen too much in Australian houses, thank goodness, because we mostly don’t have any great number of stairs.

You spent your early life in Murchison.

Oh yes. Murchison was a little—I won’t call it a one-horse town, because there was a total population of about 300, and there were several horses. It was a little town at the back of nowhere mostly doing rather impoverished dairying, because there was a butter factory. Rather astonishingly for that time, there was a hydro­electric power plant which supplied a town of 300 people, in the outback! It wouldn’t happen in Australia, would it? And this was back in the 1920s. What had happened was that a German engineer had come to live in New Zealand after the war and he was responsible for building this hydro­electric plant himself and making a living out of selling electricity to the population of Murchison. We were there in Murchison because my father was surveying a railway at that time, which was intended to go from Nelson across the mountains to the west coast; so he was away from home a lot.

We had the electricity put on to our little house, and I had a bit of early experience in electrical instrument design. I was about seven or eight and I had seen the electricians working on putting this thing together and I thought I could build something in the way of a little electric lamp myself. I had seen the lamp bulbs with the filament in them, so I made my own little electric lamp out of a scrap of flex. It blew the fuse and I was very unpopular because, of course, nobody except the electrician knew how to change a fuse. That was really my first experiment.

You left Murchison in 1928. That was a sensible move.

It was, yes, because Murchison was almost completely destroyed by an earthquake the year after we left. It even changed the course of the river and destroyed most of the houses. Out of that population of 300, 10 people were actually killed by the earthquake, so you can tell how severe it was. It was really one of the worst—if it had occurred in a city, it would have been an absolute major disaster; but there it didn’t do all that much harm, I suppose. Yes, it was good not to have been there.

You then moved to Auckland and you completed your primary schooling there.

Yes. When we went to Auckland, my father, who was a government civil engineer, was put on to being the site engineer when they were building the New Zealand Air Force base at Hobsonville, which is about 15km or so up the harbour from Auckland city. Hobsonville School was not a success. It was certainly the worst school I have ever had any association with. The headmaster, I am sure, was clinically insane. He used to spout nonsense most of the day to the children. On one occasion he got annoyed with one of the boys, and the punishment in those days was a strap on the hand. This boy was standing there, being strapped on the hand by the headmaster for a long time until the headmaster gave up exhausted. It was really an appalling sight. Anyway, that was all long ago and it doesn’t happen these days, I am sure.

But after that, my brother and I were both sent to a school in the city, which was much better; the Wellesley Street primary school. There, the education generally was fairly good, but there was one deficiency and that was in science education. I remember one thing that was good. They showed us a lovely old experiment of taking a kerosene can and boiling up water in it until the steam pours out. You then screw the cap on it and let the thing cool and the whole tin collapses under the pressure of the atmosphere. This is a very nice demonstration of atmospheric pressure—and that I remember very well. But I also remember the headmaster giving us a lecture on combustion. He told us that, when things burn, they burn in oxygen and he went on to say that the sun was a very large fire which is drawing oxygen from the earth and that this was the reason why, if you lit a fire in the sunshine, the fire would go out, because the sun was taking the oxygen away. Words fail me.

I gather at that stage you became a Meccano builder.

I was very fond of Meccano, it was a fascinating hobby. It is surprising how many scientists do attribute their leanings in later life to having played and built things out of Meccano in their childhood. I was fairly successful with it and, in fact, I won one or two international prizes for models that I built, because you could build a model and take a photograph of it and send an explanation of it to the Meccano magazine in London and, if you were lucky, win a prize. And I won prizes twice, which I thought was really great.

Science fiction also took your interest.

This was about 1928 or 1929, and the first science fiction magazines in America were just coming out. I think Amazing Stories was one of the first and there was another one called Astounding Stories, which later I think transmogrified into what is now Analog Science Fiction (previously Astounding Science Fiction). I immensely enjoyed these stories and they had in those days a didactic quality about them; they were teaching you about basic science as well as making stories. So I learned at that age, 11 or so, quite a lot about things like the structure of atoms and electrons and protons and electric currents and all that. It was delivered as part of the story and very well done in some of those early stories. Anyway, it certainly hooked my imagination on scientific things.

High school experiments in photography and explosives

You won a scholarship then to Auckland Grammar.

Yes. At the end of my primary years, I was lucky to get a small scholarship. It didn’t pay a great deal, but then this was at the height of the depression and any sort of contribution to expenses was extremely welcome. It did pay for all my books and the very small term fees that one had to pay there, so it was a considerable relief. At that time, my father was actually unemployed. The depression had resulted in a lot of people being laid off, and he was one of them, during several years of my secondary education. Auckland Grammar School was really a very good school. It had first-class teachers, all graduates in their particular fields, which wasn’t the normal thing at every school in those days. In the university examinations it usually topped the field in the country. But you must remember that we are talking about a country which at that time had a population of 1¼ million, so being top of that wasn’t such a tremendous achievement perhaps; but, nevertheless, it was something to be quite pleased about.

And you took up photography at that period.

That was soon after I started at secondary school. My father had an old folding camera. This was a very nice Kodak f.8 folding camera with a particularly good lens, and I had a lot of fun taking photographs with that. I didn’t have a proper darkroom at home, but I was very small and I used to climb up a step ladder into the top cupboard in the wardrobe and develop my films in there, it was quite a good darkroom. Later on I set up enlarging facilities and things in my bedroom, which I just used at night when one didn’t have to worry about too much light getting in.

You were fairly small at that age and not very keen on sport and you took a job as a lab boy.

Yes, well, not only small, but I also had a very nasty temper and, of course, I used to get into rages. This is a wonderful sport for the other boys, to bully me until I got into a rage and raced around screaming, and I didn’t like this at all. However I found it was possible to escape by becoming a lab boy and doing work in the laboratories to get things ready for classes. By doing this, I was able to be out of the playground all the time and for a period after school and also during the sport periods and the compulsory military drill, marching you around with a little rifle on your shoulder. Altogether, it was a great opportunity to learn a lot of chemistry as well—and physics; I was in both the labs.

I gather that you enjoyed making explosives.

I don’t know a boy that doesn’t really, if he’s given the chance. There were some explosions that were a routine part of the demonstrations that the masters used to give. One was nitrogen triiodide, which you can make very easily in a lab by just crushing up iodine crystals with concentrated ammonia and letting it dry. This is an interesting explosive. It is extremely sensitive; it blows up if you touch it, which is quite handy for demonstrations of sensitivity and that sort of thing. It makes a tremendous noise but does hardly any harm. On one occasion, I had prepared a sample of this the previous night for a demonstration the following morning. It was in a filter funnel and I was carrying it around from the preparation room into the classroom and it blew up in my face with a tremendous bang. This was during a school assembly period, and it really shook the whole building with sound but it didn’t do any harm. Even though the thing blew up in my face—even the glass funnel wasn’t broken. It was just noise. It did interrupt the prayers, but then they started up again, with more enthusiasm.

I gather that one explosion was when the students were marching around.

Oh, yes. That was not a demonstration; that was me fiddling around with things. I knew what I was doing and I knew that it wouldn’t do any real harm. This was a potassium chlorate and red phosphorus explosion, which I was trying out in a fume cupboard. It really did go off with a tremendous bang and the windows shook. Again, even the fume cupboard windows weren’t broken; it was mainly noise. But it was heard outside the school, where the cadets were marching to and fro. One of the masters came tearing in to pick up the bodies and found me looking very innocent, giving some entirely erroneous explanation of what the sound was due to.

University days

At the end of secondary school, you were awarded a prestigious scholarship.

Yes. There was a scholarship called the Gillies scholarship, which was a privately endowed scholarship that enabled you to study science at the university. So I sat for the scholarship and then I found I’d won it from reading the newspaper some weeks later. The newspaper said that the university senate had awarded me this scholarship, with the reservation that I should check my entry form because it said that I was not born in New Zealand. And, sure enough, on investigation, in this form it said, ‘Were you born in New Zealand?’ and I said no. But it didn’t say anywhere, and nobody told me, that this meant that you couldn’t be eligible for the prize. So I’d spent all this time working for it and I got very cross indeed about this. It turned out all right in the end because I got a better scholarship for the university later on anyway. And the man who did get this scholarship was one who probably wouldn’t have been able to get the university scholarship; so no grudges were borne.

At university you had to decide between science and languages.

Well, I had been very good at the language side. I was very good at English essays and I think I was first or second in the country in the university examination for Latin and French, both of which I enjoyed very much. I had also been doing very well in chemistry and physics but not so well in mathematics. My mathematics education had got interrupted by one of these failures to understand something at a particular point in the course, and it did set me back probably about a year in my grasp of mathematics; I came good later. I had this decision to make: would I study science or would I study arts, in particular, languages? What decided me in the end was that I had a contemporary at the school who was rather better than me at almost everything—just a little bit, one or two per cent. He decided to take languages—classical languages; he was going to do Latin and Greek. And I said, ‘Well, if I go into the Arts side, I’ll be continually competing with him and just falling short; whereas, if I go to the sciences, I’ve got a better chance of getting subsequent scholarships and so on because he won’t be competing with me.’

This may be a rather eccentric reason for making one’s mind up, but it seemed a practical one to me at the time, so I did that. Later on, my younger sister was faced with the same choice and she was unable to decide. I pointed out to her that, if you do science, you can still become a teacher; whereas, if you do an arts course, about the only thing you can do in New Zealand is be a teacher—but, if you do science, you have chances in science as well. And she agreed with that and she did a very successful course in biological sciences and later became a rather well-known ecologist in New Zealand; she’s still going strong in that capacity.

In 1936, you took a summer job doing chemistry at a gasworks.

Yes. We had a coal gasworks in Auckland at that time; it was the only source of gas for heating. Again I was very fortunate to get a job like that in the vacation because it was still a state of severe depression. They wanted somebody to assist the chemist over the summer period, and I got this job. It started at about 10 or 15 shillings a week and gradually built up over the years until I was earning the massive sum of about £3:10 a week in the last year in which I did it, which was really quite respectable. It was a great help in building up funds for the coming academic year too, although I did have a scholarship, but the scholarship was £60 a year—that is $120 in current terms and, of course, this money was different money in those days. During my university years, one could get a good three­course meal for one shilling and fourpence in a particular tearoom down in the town, which was much favoured by those at the university. That is equal to 16c, isn’t it? It was very good value.

I gather that at the gasworks you had your first introduction to thermodynamics.

Mostly I was doing titrations of ammonia liquor and viscosity of tars and things like that. But the chemist in charge was a very good chemist. He actually hadn’t graduated, but he knew an awful lot of chemistry and was a very well­informed man. The manager of the gasworks had been reading the engineering journals for gasworks and came across an account of a process by which you can actually make methane by combining carbon dioxide with hydrogen. Anyway, he said, ‘Methane—well, we want to get methane in our gas; we know this has very good calorific value.’ So he called up the chemist and gave an explanation to him about this and said, ‘We want to get more methane into our gas, Mr Stansfield; you should tell us how to do that,’ and Stansfield said, ‘Well, yes, it’s true you can get more methane in the gas by doing this, but you have spend more energy in doing so than you would get back by burning the methane’. This is one of the laws of thermodynamics: you get nothing for nothing. And the manager said, ‘Well, Mr Stansfield, why do you think we employ people like you if not to get around little difficulties of that sort?’ That was the end of thermodynamics for the manager.

Robbie Robinson was at the Auckland University College at that time. What was his influence on your starting a career in electrolytes?

He was a profound influence and remained so for all my life. He was a lecturer who had come out from England relatively recently, he’d been there two or three years when I got to know him. He had a passion for exact measurement and a great interest in solutions, particularly solutions of electrolytes. He had studied under Harned at Yale, which at that time was the main centre for electrolyte work in the States. He had some basic equipment of absolute first-class quality—very little of it, but just enough. He had one really good five­figure-accuracy potentiometer, and one really good automatic aperiodic balance. These were the sorts of basic tools for doing all the work, plus a large thermostat which can be put up anywhere with ordinary facilities.

He was developing the isopiestic method for measuring vapour pressures of solutions and applying it to electrolytes. This was a technique which had been invented in Auckland by a student a few years before; this student hadn’t followed it up a great deal, but he was clearly a very original man himself, Donald Sinclair. When Robinson came, he saw the potential in this technique for doing high-precision work on electrolytes, and developed the technique into the form that it still has today. Robinson was also doing highly accurate measurements of electromotive forces. This was the work he put me on for my honours year and I was pretty successful in applying it, and got completely hooked by that sort of work myself.

That involved you with a lot of calculations.

It did. With the isopiestic work, for instance, you were weighing a lot of these small dishes, calculating compositions of the solutions in them and then doing further calculations based on that. In those days we didn’t have any calculators and it was all done by using logarithm tables. We used four­figure logarithm tables for doing all of the multiplications and divisions. I suppose people these days still know in theory that this is possible, but it is never done in practice, because we have calculators to do it. But to do a multiplication you had to take the number, look up its log in the log tables and take the other number that you wanted to multiply it by and look up its log, add the two together by hand and then, from the result, you look back into the log tables to see what number that corresponds to.

Doing that all the time, you got remarkably quick at it and also you learned a lot of logarithms by heart. They just came up so often with things that you were using all the time that you just knew them. For instance, I still know quite a few. I’ll give you an example of that. Do you know how the economists and politicians are always going on about the importance of getting back to one per cent annual growth and how you can’t really have a stable society without having one per cent annual growth? Well, one per cent growth can be expressed as 1.01. I can remember that the logarithm of 1.01 is 0.0043. Suppose we go on having this “stable” society for a thousand years and we multiply 0.0043 by 1,000 and get 4.3. Now, 0.3 is the log of 2, and the 4 means the 2 is multiplied by 10,000. So, at the end of 1,000 years, it means that we need 20,000 new planets to accommodate that annual growth. I don’t think we can do that.

Lab romance and the outbreak of war

You met Jean Wilson in 1939.

Yes. Well, she was a year behind me in the university entrance; nevertheless, with the way the syllabus was organised, we had some classes that we both went to. I very quickly realised that she was a great rarity—somebody who had the same sort of interests as me and the same general outlook on life, and it was just encountering a kindred spirit.

I gather Robbie Robinson put you both in the same lab together.

Robinson only had one lab to share and Jean was in the year after mine but I was still doing some work in the year after my honours. Jean was doing her honours year and, if you’re working in the same lab, it’s pretty inevitable that you end up getting married or something equivalent these days.

You were conscripted into the New Zealand Army at the end of 1940.

Yes. Right throughout the war New Zealand had conscription and I knew my turn would come up soon, and it did come up at the end of 1940. I had been doing a mathematics honours course during that year and doing some chemistry research as well. But my number came up and I was duly sworn into the army. But then they realised that they needed people with chemical qualifications to be elsewhere other than in the army. There was an ammunition manufacturing company in Auckland which was very much in need of a scientist and they pulled me out of the army and put me on to being a chemist at this ammunition company. The funny thing is that I can’t remember exactly how my removal from the army came about; but I don’t think I was ever formally sworn out of the army, so I am probably still AWOL.

The ammunition company was a small family firm which had been going for many years and was now being very rapidly expanded to produce small arms ammunition for the army. Its work was not much with explosives; it bought in the cordite and percussion caps from elsewhere and just used those in the manufacture. They were doing almost entirely metal forming work, drawing brass cartridges and the various shaping operations needed for those and assembling the bullets with the lead cores. I had to learn quite a lot about metallography because the drawing process for making cartridge cases is really quite complex and there were as many as 20 operations to get a finished cartridge case out of a piece of brass sheet. It was very much involved with annealing after the drawing processes and making sure you’d got the right crystal structure at every stage.

So I learned about metallography, especially for nonferrous metals; and this was very interesting, because I’d never done any of that in my chemistry degree. Metallography was in some of the engineering courses but certainly not in the chemistry courses. I became quite skilled at polishing metal surfaces and etching them to see the crystal structure and that kind of thing.

So this experience served you well in later life.

Yes. I think I really got a lot from those years working in the factory. One thing I learned in particular was that the whole success of these things depends on the skill of the craftsmen working on the machines. I don’t so much mean the actual women on the production line who are operating the machines—although they were a pretty remarkable lot too. They could sit there talking about almost anything, meanwhile dipping their hands into a bucket of partly finished cartridge parts and coming up with five in each hand. They would then put them into the next machine, and just go on talking, while they were doing this quite automatically; it was an amazing sight.

It was the skilled technicians, and particularly machinists in the workshop where the tools for drawing and pressing tools and so on, were being made. These people really impressed me with their mastery of the machines they used and their understanding of what to do. At that stage they were mostly working without any blueprints or any diagrams to show them what they had to do; they just knew from experience how these things were done. Later on we had to organise it a bit so that there were blue prints, but it was amazing how much was depending on just the skill and memory of those craftsmen.

In 1942 you married Jean.

Yes. By that time, there had been a scare about an invasion from the Japanese and the factory had been moved from Auckland down to a rural site in Hamilton, about 150 kilometres south of Auckland. There, we were set up in a rather rural surrounding, with little low buildings on each side of the road for containing those various stages of the operation. In 1942 we got married. Actually, by that time Jean had become a full-time, but temporary, lecturer to replace Robinson, who had gone to America to do some war work there—Canada, I think. Jean was continuing with some of the research work that we were always doing. But I was living in Hamilton and we just used to visit each other at weekends.

I gather that at the marriage you gave each other an unusual wedding present.

We were both very much interested in the calculations involved in doing all this work and we had had an introduction to the utility of having a mechanical calculator. We’d been lent one by a man we got to know who had come out from Europe just before the war. He had a little German calculator which was not a well­known make but it was a wonderful thing for us because it could do all these multiplying calculations we used to do by logs, very quickly by hand. So we wanted very much to have one of these for ourselves. We advertised in the paper to see whether anybody had one of these for sale. Sure enough, somebody did turn up with a Marchant hand calculator and so we latched on to this and we gave it to each other for a wedding present, which seemed ideal. Some people thought it was a bit eccentric. My father didn’t see the point at all; in fact, he said something caustic about people who have to give their wives a multiplying machine. Anyway, we did value that and used it for many, many years afterwards as our main tool of calculation. In fact we were still using it long after we came to Armidale.

This example is just multiplying two four­figure numbers together. We have, let’s say, 1234 and we multiply it by the reverse, say, 4321. So the one goes in that place, the two goes there, the three goes there and the four goes there—and 4321 times 1234 gives you 5332114. Division is slightly more complicated. But the great virtue of this for our calculations was that a great many operations had to be done by multiplying two four­digit numbers together and adding that product to the product of the previous ones, doing this for a whole series of numbers to do numerical integration. The beauty of this is that the previous total stays there and you don’t clear it, and you just add the next one to it and automatically it accumulates the totals. So it can be quite quick even for that operation. It is probably just as quick as trying to do it on a small hand calculator today. It can be capable of eight­digit accuracy in the multiplier and nine digits that way, and the product register I think 15 digits, so you’ve got plenty of accuracy. This kind of thing was the basis of all sorts of calculation until the electronic calculators came into the picture.

Moving across sea and desert to the University of Western Australia

At the end of the war, you were offered a position at the University of Western Australia. I gather that you went by flying boat.

Oh yes. The air connection to Australia in those days was by big flying boats, which I think were a civil version of the Catalina flying boat. The flying boat was a wonderful way to travel by air. It was slow—they only did about 80 miles an hour but they had this enormous hull in which a couple of dozen passengers could walk about freely and sit down at tables to have their meals and even have beds to lie down on if they wanted to rest. At 80 miles an hour it was a fairly long trip, even across the Tasman. But it was really a most interesting way to fly. They went on going from Sydney for many years afterwards. Then, of course, when we landed in Sydney it was a matter of hopping in a series of small planes like DC3s and putting down at several points across the desert to get more fuel to fly to Western Australia. I came by myself because we had to arrange for things like housing and so on when we got there. So Jean stayed behind with our child Helen and she followed me later on by ship, when I had found somewhere to live, which didn’t take very long.

At the University of Western Australia, you started the immense task of evaluating the activity coefficients of electrolytes.

We had done a lot of work ourselves and Robinson and his succession of research students had done a great deal in this direction, but it still hadn’t been coordinated. And other people too were using the technique a little. We wanted to get an overview of all this work and try to systematise it and develop some sort of theory for what was going on in these electrolyte solutions. So I did a lot of compilation and recalculation of all of the results to put them on a common basis—defining what the vapour pressure standards were—and just began to see at that stage the outline of what was to be a major part of my ideas about these solutions.

A lot of the theory of solutions at that time was concerned with very dilute solutions; in fact, some people called them slightly polluted water. But the theory worked best in those—the Debye-Huckel theory, which really was a theory for very dilute solutions. But, of course, the things of importance and interest in real life are not dilute solutions but very often extremely concentrated ones. This isopiestic method had taken us right through the concentrated region up to saturation of the solution where you couldn’t dissolve any more. These are the things that matter to industry particularly.

The behaviour there was quite different from anything the theory of dilute solutions could predict or cope with.

When investigating the concentrated solutions I found an interesting feature in the activity coefficient properties, which are a guide to the energy of the ions in solution. The activity coefficients in dilute solutions start off at unity then go down as the concentration increases and then turn up and go up to extraordinarily high values in very concentrated solutions. I think the highest value we found in a concentrated solution was in uranyl perchlorate, which has an activity coefficient of something like 1600 in the concentrated solutions. Formally speaking, that means that the ions were about that much more active than you would expect them to be.

I realised that these high values always occurred when you had ions which were thought to be strongly interacting with the water and becoming, what are called hydrated ions. Now, rather curiously at that time, hydrated ions had been known about since the 19th century, and people knew that there must be something of this sort. But somehow the theory of hydrated ions had become unfashionable and people were concentrating on physical approaches, like the Debye-Hückel theory for dealing with interactions between the ions. But it didn’t really have anything to say about the interactions between the ions and the water in which they were dissolved. Water, of course, is the reason why they dissolve in the first place.

So I found that spectacularly high results were occurring in these concentrated solutions where the ions were strongly hydrated, and I was able to develop a properly based thermodynamic theory of what happens if ions are hydrated like that; some of the water is combined with the ions themselves. This was the first time it had been formally and successfully treated by proper thermodynamics, and I was able to combine the thermodynamics of hydrated ions with the Debye-Hückel theory. This resulted in a pretty simple theory which accounted for the whole behaviour of electrolyte activities right from dilute solutions up to saturation in many cases. So it was really quite an important development.

At the same time that I was having this idea in Perth, Robinson in Auckland had been working on a different approach, which started from the very concentrated end. His idea was that, in these extremely concentrated solutions—and I mean they can be very concentrated; there can be one water molecule for every ion in some cases—his idea was that you would treat this by thinking of a lattice work of ions, positive and negative ions alternating in the lattice, rather like the solid crystal, but with water being adsorbed on the ions in this lattice by something similar to an adsorption process of water on other materials. He treated this by the standard isotherm for adsorption, which is called the Brunauer-Emmett-Teller isotherm. It reproduced these concentrated solution results extremely successfully, and has been very widely used since, as one of the best approaches to extremely concentrated solutions. These two ideas were clearly very closely associated and we published them in a joint paper in 1948. It became one of the major papers in changing people’s views on hydrated ions and, as it were, bringing hydrated ions up to date and making them fashionable again. That paper has been quoted a couple of thousand times probably on its own. It has had a very big influence on the electrolyte field.

Shortly after you arrived in Western Australia, you joined the Australian Chemical Society and were awarded the Rennie Medal. This led to other awards as well.

This was a very fortunate event. I hadn’t been in Australia very long, but I had quite a few published papers at that time because of the work I had been doing in Auckland, and some of what I had done in Perth had been published too. The local branch of the Australian Chemical Institute (now the Royal Australian Chemical Institute), which I joined almost as soon as I arrived in Australia, asked to nominate people for the Rennie Medal. The Rennie medal is awarded to young researchers under the age of 30 or 35 and has no restriction on the work having been done in Australia. So they nominated me for work that I’d mostly done in New Zealand; and, lo and behold, I got this medal, which was rather unexpected. But that was very nice.

This emboldened the institute later on, when they got a circular from the Royal Institute of Chemistry in London, to suggest people for one of their very prestigious medals, which is called the Meldola Medal. This was to be awarded again for research work by a young research worker with an age limit and another interesting restriction, which echoes the case of the scholarship I had in New Zealand: the chemist must be of British birth. I was of British birth and had quite a few publications, so they nominated me. Rather to my surprise, I got that one as well. That was the only time that this medal from the Royal Institute of Chemistry in London had been awarded to anybody outside the British Isles. This was a bit of a novelty and is certainly a thing which has stood me in very good stead in subsequent life.

A bit further after that again, Imperial Chemical Industries was offering fellowships for people to do postgraduate research in England. This notice came around to the branch and they drew this to my attention and said, ‘Why don’t you apply for this? You might get this.’ So I duly applied and I got this one! I began to realise that one of the reasons for this success was that I’d had a bit over a year in Auckland, before the war started, to do some more research after honours. I had also managed to fit in bits and pieces in Auckland during the war, for part of the time, so I had quite a few publications; whereas most of my contemporaries, in England particularly, had been very much engaged on war work and hadn’t got any time for publications. So I was, in that sense, just very lucky, and that luck seems to have been with me a good deal of my life actually.

A PhD at Cambridge studying diffusion in liquids

You went to Cambridge on the fellowship and did a PhD.

Jean and I went over by sea and, at that stage, we had two children, Helen and Anne, we arrived in Cambridge about a day after Christmas, I think, in a blinding snow storm. Luckily, a friend of ours had found a little place for us to live in a village about five miles outside Cambridge. It was almost impossible to get any family accommodation in Cambridge, because the place was chock-a-block with students living in and out of college and it was very hard to find anything for a family.

To go to Cambridge, you have to be a member of a college, so I applied to Pembroke College on the basis that Sir George Gabriel Stokes had been Master there and a professor in Cambridge; he was extremely well known there. So I just mentioned that I did have some distant connection with him and they welcomed me with open arms. The college treated me extremely well. I couldn’t live in college because of my family commitments, but they were really very kind to us and gave us a lot of help during that period.

There you developed the stirred diaphragm cell method.

When I got there, I didn’t really know what I was going to work on. I went on for a few months finishing some calculations in connection with the work I had been doing in Perth. This took two or three months, while I was looking around. Incidentally, that calculating machine I was using all the time, made a tremendous impression: here was a man who actually had his own calculating machine. The theoretical chemists in Lennard-Jones’ group used to borrow it from me to do their calculations. At that time, as a matter of fact, the development of the first stored-program computer, called EDSAC, was being developed by Maurice Wilkes in the mathematics and computing section there, and I had a little contact with that during its development. Wilkes gave some lectures on computing and, for these lectures, everybody was provided with a hand calculator—because, of course, the computer wasn’t working yet—and he talked about computer programming, and that was all very interesting.

Well, after this couple of months, I decided that an interesting field to work on would be diffusion in liquids. Diffusion in liquids is very closely connected with two of my other interests, which were the thermodynamic properties of solutions and electrical conductivity. The difference between diffusion and conduction in an electrolyte solution is that in diffusion the ions are all moving one way from a concentrated solution to a dilute solution, whereas in conduction, of course, positive ions move one way and negative ions move the other. But there is clearly a very strong relationship between these two processes and more data was urgently needed on diffusion.

There were very few reliable data. At that time people were realising the importance of diffusion, in connection with the theory as well as practice, and lots of reviews were being written. In the chemical literature there were several reviews on diffusion, and they all reviewed the same things and there was hardly any experimental data to review. Except a few very recent measurements in very dilute solutions, which were being done at Yale, they all went over the same old ground. It was clear that there was a very strong need for the actual measurements, so I decided to do this.

One of the methods that had been tried was this diaphragm cell, in which there was a sintered-glass diaphragm in the middle of a cylindrical cell and solutions diffused through the diaphragm from one side to the other. The diaphragm is a device to stop the liquid from mixing mechanically and just let the ions go through so that the liquids don’t actually mix into each other mechanically at all. This had been used and had worked moderately well, but it had some difficulties. One of these was that there was a layer formed near the surface of this sintered-glass diaphragm, which was stagnant, and its immediate thickness was not calculable, so you didn’t really know the distance the ions were diffusing over. I was trying out various things about the effect of the angle at which the cell was tilted and whether, if the denser solution was on top, would it still work? and, if it was underneath, would it not work because of the formation of these layers? If you had the stronger solution underneath, you would get a bit of liquid going through but then staying on the diaphragm because it was heavier than the lighter liquid on top; whereas, if you put the cell the other way up and it was difficult to be sure that you weren’t getting actual liquid flowing through the diaphragm instead of just diffusing.

I was playing around with this and John Agar was interested in what I was doing at the time. I had just started to work on this for a PhD, and John (who ended up being my supervisor) suggested that it might be possible to stir it magnetically. At that time this was a pretty revolutionary suggestion because magnetic stirrers were quite scarce. When you wanted to stir something, you stirred it with a stirring rod. These little magnetic stirrers that are used everywhere in labs now were pretty rare and we didn’t have one anywhere in the Cambridge labs. But this idea was clearly what we wanted. So I found a way of making the stirrers using little bits of tubing, with a bit of iron wire inside, and made these rotate by having a big horseshoe magnet rotating around the outside of the cell. This made all the difference to the whole principle. You could still have the denser solution underneath, so that it didn’t have this liquid falling through by gravity, and the less dense solution on top, so it was gravitationally stable, and you could then get rid of this effect of the layers of liquid accumulating near the glass diaphragm by having these magnetic stirrers going around stirring the whole thing up so that each compartment was kept uniform in composition. This meant that the thing was a complete success in terms of measuring diffusion coefficients.

I did a lot of measurements on simple electrolytes with this stirred cell and got them into publication before the end of my second year. All the simple 1:1 electrolytes that have ions of a noble gas structure I measured, over the next year or so. It was a very slow process because these diaphragm cells have to run for three or four days to get enough diffusion occurring to make a useful difference to the concentration. What you do is know the concentrations to start with, then you set the diffusion process up and, after a few days, you measure the concentrations again. You find that the concentrated solutions become more dilute and the dilute ones become more concentrated. But it needed some pretty accurate measurement of the concentration to be able to calculate this with sufficient accuracy.

So I was spending most of my time—in between the three- or four-day periods of doing that diffusion, doing a lot of very exacting quantitative analysis to determine the concentrations in those cells after the process had gone on for a while. This meant a lot of weight titrations, particularly, to get enough accuracy.

Again, Cambridge didn’t have at that time an aperiodic balance, at least not one that I could get at. I needed one right on the spot to do all my analyses, because I was weighing all the time. I couldn’t just walk across a quadrangle carrying these things and come back again each time I wanted to weigh something. Luckily, ICI came up with a gift of an aperiodic balance and that made the whole thing much better.

Return Down-under to conductance of electrolytes

When you returned to Western Australia as a senior lecturer you continued the diffusion studies.

Yes. Western Australia still didn’t have a PhD course, so I had no PhD students, but I had some very good students for the BSc with honours; that was a three­year BSc course and a fourth year for the honours year. I particularly remember John Hall. We built a cell for a Goüy diffusiometer out of perspex. This is an extremely precise piece of engineering, normally done with milling machines and high­precision tools. But he made this thing by hand entirely, cutting out all the pieces and getting them to uniform thickness and polishing them and so on—and it was very successful. For the optical system, we did rather well too.

After the war, in Cambridge, one could buy ex­war equipment for ridiculous prices, and one of the things I had bought was an aerial reconnaissance camera. This had—I forget whether it was an F 2 or 2.5 lens of 8-inch focal length. Imagine the size of it. It was a great saucer of a lens and, furthermore, as it was used for aerial work, it was perfectly corrected for infinity. So it was ideal for the main collimating lens for the Goüy optical diffusion method and it worked very well. We made a very successful Goüy optical diffusion apparatus by essentially the efforts of one extremely capable honours student. I even brought the finished thing over to Armidale when we came there later and we did more diffusion measurements.

In Perth, I began doing some measurements on conductance of electrolytes. I mean, I’d been using conductance measurements that other people had done as an important part of the theoretical development, but I hadn’t really done any myself with any accuracy. Again there was an extraordinary lack of data for solutions at high concentrations — the kinds of solutions that are always turning up in industrial processes and so on, even of the concentration of sea water—hardly any really accurate data. Of what there was, most had been done with rather inferior equipment around the 1890s, and in 1950 I wanted to know the conductance of one molar sodium chloride solution and there was really no good data for it. Good data up to about one-tenth molar was typical of the electrolyte data at that time because, again, all the interest had been in checking the Debye-Hückel theory and finding an explanation of behaviour in dilute solutions, whereas I wanted to know about concentrated solutions. So I decided to get some measurements going myself.

I found some old, very accurate conductance bridge equipment meant for measuring the resistance of post office lines. It was a thing called the ‘post office box’, which was extremely precise, with an accuracy of one in 50,000 of the resistances. In other words, it was the basis of the measurements. Furthermore, it was non-inductively wound so that you could use it with an alternating current, as needed for the conductance measurements. So we set this up and did quite a lot of good, accurate measurements on that. Soon afterwards, we got enough funds to get one of the classic conductance bridges at the time, the Leeds and Northrup conductance bridge. This conductance bridge was in general use in most of the research laboratories where electrolyte solutions were being studied. This is a very precise bridge, indeed it had one in 100,000 precision. This was then used for more of the measurements. When I left Perth, a lot more measurements were done by John Chambers on many more concentrated solutions, and they are an important part of the data base for these things now.

Writing of the definitive text Electrolyte Solutions

Robbie Robinson moved to Singapore while you were in Western Australia and you started writing Electrolyte Solutions.

That was a book that we planned to write; we had been planning it for a little while before and, while I was in Perth and he was in Singapore, we got down to it. There was an extremely good airmail service, almost overnight there at that time. We started writing this book and decided to call it just Electrolyte Solutions.

Robbie produced an original draft which I felt was too similar to the classic work of Harned and Owen, which wasn’t surprising because he had been very heavily under the influence of Harned particularly. I wanted to have something more readable; one thing about Harned and Owen was that it’s a very fine book but it’s hard to read. We decided on a different structure in which we had a chapter on experimental work, saying how things were done, a chapter, for instance, on conductance and how you measure it and then another chapter on how you interpret those results once you’ve got them, on the theory side. We did that a lot and had chapters over several topics—the first half of the book, more or less, and this proved to be a pretty good way of looking at it.

This book was published just before I left Western Australia. It took us a couple of years at least in the writing, I suppose, and a great deal of airmail went to and fro from Singapore. Robbie got all the typing done in Singapore, where he had a very expert typist. It was all typed out on that thin India paper, which made the airmail cheap and so proofs were shooting to and fro like that between Perth and Singapore very effectively, not quite as quickly as email but very nearly. The book actually got into publication before I left Perth.

During that work, you found there were serious calculation errors in some of the other published work.

That was another rather interesting one. I’m not sure whether that was while writing that book or during my first stay in Perth in 1946 and 1947. Anyway, it was certainly while I was in Perth. I was working on lanthanum chloride, again calculating the correct values for the activity curve, for instance, just checking through calculations on other people’s work. Lanthanum chloride had been studied by some extremely accurate electromotive force measurements combined with measurements of the transference numbers by what was regarded as the most refined and exact school of study of electrolyte solutions in the world, the Rockefeller Institute in New York. It was primarily a medical research institution, but they had some interest in electrolytes because of electrolytes in blood.

They’d got these two extremely capable, brilliant experimental workers on electrolyte solutions and they were doing really fundamental work and getting extremely accurate results. We’d used their work on other electrolytes extensively in getting our standard data for the isopiestic method. Their work on lanthanum chloride had shown anomalous behaviour which nobody understood, in the way the activity curve results approached the limiting results, according to the Debye-Hückel theory. In all other electrolytes studied, the activity coefficients had gone to this limiting Debye-Hückel result from above, whereas, with lanthanum chloride, the results were approaching it from below. This was extremely anomalous and nobody could explain why it was occurring. There was no lack of theorists who were providing brilliant explanations of why it was so, but I found that these results couldn’t be combined sensibly with the isopiestic results that we’d got. The results were for dilute solutions, but they would not join up with our isopiestic results, which were for solutions from about 0.1 molar up.

So I got to work on getting right back to the fundamentals of their calculation and going right through everything. Luckily, all their raw data was published in the papers, so I could actually go through it. I found that these people, for whom I had enormous respect and who were undoubtedly the premier research workers in the field, had made a serious mistake in their algebra. To put it briefly, a numerical integration at one stage of the calculations had to be done and, let’s say, instead of integrating ydx, they had integrated xdy. That, as any mathematician will realise is not the same thing by any means. So all the results were wrong, all their calculations were wrong and the published results they’d got for lanthanum chloride were wrong, and this was the explanation for why it was showing this anomalous behaviour.

I wrote off to them rather urgently and pointed this out and got a most embarrassed letter back from them saying, ‘Thanks very much for telling us this; we’ll publish a correction as quickly as possible’—and they did. Some years later when I was visiting New York, I went to see them. I happened to arrive on foot in a pouring rainstorm and, of course, all the taxis were taken up by people who wanted to get out of the rain too, and I didn’t know how to get a taxi in New York. So I walked to the place and got drowned in the process and, when I arrived there, they treated me like a king.

A fiery start at the University of New England

You moved to the University of New England in 1955. What drew you there?

It’s always flattering to be ‘invited to apply’, which is a pretty fair indication that they want you. There weren’t that many chairs going, of course, and I hadn’t really thought particularly of being a professor and head of department, but I imagined I could do it. Of course, the increase in salary was very attractive. At that time a professorial salary, which I think had just been put up to £2,000 a year, put one in about the top one per cent of taxpayers in the country. It was a very different sort of scale of things.

The environment in Armidale also attracted me. It is an extremely pleasant place to live. I really did not want to live in a big city. In Perth we’d lived outside of the city in the very pleasant suburb of Nedlands. But I really didn’t want to have a life where I had to commute into a central university somewhere. In Armidale, you don’t have to commute anywhere, because everywhere is within 10 minutes of everywhere else. I just liked the idea of starting up afresh really.

There was, in fact, a department here and quite a good department. It had been there since the very early days of the University College in 1938 and it was staffed by some very good and capable people. One of them was Noel Riggs, who had been a co-lecturer with me in Perth in 1946 and 1947; he was one of those appointees too. We’d also been at Cambridge at the same time. He’d been here as a lecturer in organic chemistry and was, I think, largely responsible for getting them to invite me to come as the professor. We came over in August 1955, just in time for some of the nice cold weather. We moved into this house very quickly; I’d selected it previously, in fact. So this change in our life came off quite quickly.

I found the atmosphere of the rapidly growing University of New England very, very stimulating. When I arrived, we had 300 students and 100 staff. It sounds utterly disproportionate and it was, because clearly, if you’re going to expand your student numbers, you have to have the staff first before you can think of offering new courses. So there was this large imbalance in the number of staff to students. That changed fairly quickly and the staff­student ratio approached more normal sorts of values, but they were good for quite a long time.

So we went about setting up the department. There was one great setback in 1958. We had built a little wooden building to house physical chemistry, which was built during my first year here. Adjacent to it there was quite a big building made of a steel frame and asbestos walls, and this housed nearly all the science faculty. There was organic chemistry and physics and botany and zoology and some odds and ends of other subjects too, all housed in this one large building. Some new laboratories were being installed for organic chemistry too; they were being completely rebuilt and they were just about finished. In February 1958, I got up in the morning and looked out towards the university and saw a great plume of smoke rising up and realised it was right on the site of my new building. So we rushed out in the car to see what was going on and found this old building, called the Belshaw building, was well alight and there was no hope of recovering anything.

There were great explosions going on from exploding gas cylinders and a lot of general excitement. We were very concerned that the flames would spread to the closely adjacent new physical chemistry building, and we were racing around there with pieces of rubber tubing connected to the taps to spray down the walls to stop them from firing. One of our lecturers, Ray Stimson, got up in the eaves in the roof with some of his students and stopped the embers from getting in to set the place on fire; so that building came through it all right. But the destruction was pretty dreadful because nearly all the science departments had been completely wiped out and students had lost their honours theses and a lot of research work was lost. We also had the prospect of starting up a new term in a few weeks time.

There was a vast amount of racing around, trying to organise spaces where people could have classes and laboratories and so on. Luckily, one new building in the rural science faculty was under construction and we were able to use that for first­year chemistry and physics until the buildings and destroyed things could be replaced. We started up the new term only three weeks late, which was pretty good going.

It was certainly an object-lesson to all of us to be extremely careful about fire in the future. As a result, all the university buildings were fitted with fire sprinklers and a ring main was put in right around all the university buildings to provide plenty of water. There had been a shortage of water available for the fire engine to put things out. Not that I think they could have; the fire had too much of a hold, and it was a fire going on inside an asbestos walled building designed to keep the heat in, which is not going to be easily stopped. But we’ve had no major fires or fires of any sort since.

You enjoyed showing interesting demonstrations.

I could always get the attention of my first-year class when talking about chemical reactions by having an ordinary party balloon filled with a mixture of hydrogen and oxygen, which is sufficiently light to make it float in air and letting it up on the end of a string somewhere near the ceiling and then igniting it with a taper tied to a long blackboard pointer. It goes off with a wonderful bang and the students really get to understand that a chemical reaction can result in a lot of energy production.

Another one I used to do, in talking about the laws of thermodynamics and energy and entropy, involved a pair of coffee tins. One of them is what I call the energy tin. That one, if you put it at the top of a sloping board, it runs downhill, as one might expect. But the other one I call the entropy tin; I put that at the bottom of the hill and it runs up of its own accord. I tried to keep the subject interesting in various ways like that. Thermodynamics is generally regarded as an extremely dry subject, but things in it can be fun.

Busy and productive lab

I arrived in Armidale in 1961 to start my graduate work with you. At that time, there were a number of visitors and they were exciting times. Do you have any memories of those visitors?

One of the first was John Agar who had been my supervisor in Cambridge. He was very interested in something I’d recently discovered. I hadn’t discovered it, but I had discovered one of its unexpected effects. That was that the Soret effect of thermal diffusion, in which John was very interested. It could be responsible for quite significant errors in conductance measurements, unless you knew about it. There was a paper on the Soret effect which I think has affected some people’s way of doing conductance measurements.

We got ideas from a lot of people. Loren Hepler, I remember particularly. Jean, Loren and I set up a system for measuring changes of volume on mixing dilute electrolytes with water. This sounds like a fairly boring thing to do but, in fact, it’s got a lot of theoretical interest. One needs to work on extremely dilute solutions and we devised a method of doing this. Ordinarily it’s done by just measuring the density of the dilute solution, comparing it with the density of water and doing some calculations on that. Of course, the more dilute the solution is, the nearer the densities of water and the solution are together. When they get very close, it’s not sufficient to work to a typical ordinary density measurement of about one part in 10 to the fifth. You have to work to much higher accuracies—one part in 10 million. You can’t do this by direct measurement of densities, no matter what method you use.

We had a means of directly measuring the volume change by the movement of water in a capillary tube when a small amount of concentrated solution is mixed with a large amount of water. This involved some manipulations, to first get the whole system to a very constant temperature, much better than a thousandth of a degree. And then to pull off the lid on a capsule containing the concentrated solution so that it mixed up with the bulk. It could then be stirred to make sure that it was uniform and you then observed the volume change in this capillary tube.

We had considerable discussions; Jean and I particularly just differed on how the lid should be pulled off. Nothing could be going through the wall to pull it off. Jean said, ‘You could do this with a magnet,’ and I said, ‘But I don’t think any magnet we’ve got could be strong enough.’ She said, ‘Well, try it anyway.’ So we tried it. There was a little bit of ordinary iron connected to the lid. I got a great big magnet which came from a resonant cavity magnetron, as used in radar things during the war. We brought this magnet up to it and, sure enough, it pulled the lid off. It also pulled the iron armature, which we were using to do the pulling, right through the wall of the flask and broke the whole thing. So I was quite convinced that it was strong enough. We just reconstructed it, of course, and proceeded to do all the measurements very successfully, but being a little more careful in how we handled the magnet. I realised that I should always take my wife’s advice on what would work.

I also met my wife, Barbara, while we were both doing conductance measurements in your laboratory and we were fighting over the thermostat. This must have amused you and brought back some memories.

It did indeed. Well, Jean and I didn’t greatly fight over the things in the thermostat because we’d found a modus operandi. But I know that you and Barbara with that oil bath were much more restricted in volume and the space you could get things into. I wasn’t surprised. I know contiguity—especially when people are of similar spirits - is very liable to lead to a bit of romance; my romance lasted 61 years and I hope yours will do the same!

The unique feature about Armidale and the chemistry department at UNE was the access to excellent electronic and technical staff.

I mentioned earlier my impressions about the importance of the craftsmen and technicians in keeping things going and making things. We were very fortunate in Armidale. We had a superb mechanical technician named Colin Tuxford. He was a fitter and turner, but also for very fine work he was unequalled. He is now unfortunately dead. But he was really out of this world in his ability to just take your rough sketch of an idea and produce very quickly a perfectly working piece of apparatus.

As for glass-blowing, the first glass blower we had was John Clack, who was quite good; but Lloyd Hodges, who is still alive and still doing work for the university in glass blowing, could make almost anything out of glass. He was just so skilful it was really impressive. In making those calorimeters, for instance, he could take these little stainless steel paddles, which Colin Tuxford had made and seal them up inside a glass vessel without melting or scorching any of the metal. He was really quite exceptional, and he was one of the people who made the kind of work we did with the calorimeters possible. We just could not have done it without them.

We also had the help of a series of extremely good research assistants, mostly women, who were qualified through laboratory assistant courses. These women were very good at actually running the apparatus and doing the routine parts of the experiment. Some of our calorimeters, you may remember, were originally based on a design which was computer controlled but, because of the higher precision of our equipment, this didn’t offer quite the same promise of operating well. We found that the women could do far better than any computer could in controlling the progress of the operation and, furthermore, of course, they were able to do all the preparatory work, which no computer could do. So for many years we had research grants from the research grants committee which enabled us to employ these research assistants, who again were very important in making the large output we had possible at all. I am thinking particularly of Marion Adamson, Marion Costigan and Carol Burfitt; and Allan Richards was another very good man we had.

For my PhD, you suggested that I change fields and work on solutions of non-electrolytes and mixtures of non-electrolytes, particularly mixtures with large and small molecules.

This came about really because I’d been thinking about the entropy of mixing of large ions with small ions and with water. This is a very complicated problem because of the electric charges on the ions as well. I thought we could shed some light on it by working with large and small molecules which are not electrically charged—typical organic molecules. We used this large bulky molecule, octamethylcyclotetrasiloxane, with small molecules like hexane and benzene. There was probably a difference of at least two times in the diameter of these roughly spherical molecules, so I thought it should help to get some information. I thought you could do some measurements of vapour pressures and, by doing these at different temperatures; we could arrive at the entropy of mixing of these molecules. So I set you up to do that and then went away to America for a year and left you to it. You proceeded by yourself very successfully to follow up on this idea and had an apparatus in full production before I came back!

Then we got more interested in the non-electrolyte mixtures themselves, which proved to be just as interesting, in many ways, as electrolytes had been to us, and extended our work into working with measuring the heats of mixing in calorimeters. Then we followed up with changes of volume, which we found could also be studied in a continuous method. This was all based ultimately on the idea that an American chemical engineer named van Ness had had, working at Rensselaer Polytechnic in New York State. His idea was that you could do the mixing at a constant temperature by mixing slowly and at the same time adding or subtracting heat from the mixture by suitable devices, either heaters or cooling devices, and accurately measuring the amount of heat you added or removed to keep the temperature constant. This idea of his just transformed the whole field of calorimetry overnight, by getting rid of all the sources of error at once.

I was very impressed with this and we followed that up in developing our calorimeters, which were different in design but followed the same basic idea that the mixing should be done at a constant temperature rather than allowing the temperature to rise or fall through the mixing or fall and then measuring the fall or rise. We went on to devise all sorts of other apparatus for measuring different physical properties based on the same idea; changes of volume, changes in dielectric constant. It branched out and became a very big investigation and a very successful one, resulting in Armidale becoming established as a centre for non-electrolyte work at that time. Partly that resulted in you [Professor Ken Marsh] later on going to Texas A&M and becoming Director of the Thermodynamics Research Center to compile for them great masses of thermodynamic data, which you are still very active in and very successful in.

What sparked your interest in thermodynamics of alcohol solutions in nonpolar solvents?

I’d been interested in these earlier from some more or less rough calculations I’d done in Perth looking at some results which had been published in the Australian Journal of Chemistry. Solutions of alcohol in nonpolar liquids like benzene and cyclohexane. The explanation of these results was clearly that the alcohol molecules were only there as single molecules in extremely dilute solutions. At any ordinary concentration, the alcohol molecules would be grouped and stuck together in pairs or triples or even larger groups. I wanted to go into this properly. We did a lot of measurements of high accuracy on the thermodynamic properties of the alcohols—several alcohols, but mainly ethanol—in various different organic solvents and found a lot of interesting relations between the nature of the solvent and the results that one got there.

In particular, I was able to work out quite detailed models of what happens in very dilute solutions, where perhaps you start with almost only single molecules and, as the solution gets more concentrated, you have pairs or dimers forming. Then the really interesting thing was that, at a certain concentration, which is usually about the lowest concentration which most of the previous measurements had gone, you quite suddenly start getting much more association. I’m pretty sure—and we were led to this conclusion by looking particularly at the dielectric constant data— that this is due to the sudden appearance at this concentration of rings of associated alcohol molecules, which, when a ring is formed, if it is not strained, has extra energy and entropy loss. This tends to make itself seen in the vapour pressure data very clearly. I was able to interpret this behaviour of the alcohol solutions rather well in terms of an associated model in which the ring formation is taken into account properly. That made a great difference; otherwise, the very dilute solution behaviour cannot be reconciled with the behaviour at higher concentrations, where most of the work had been done. So that was my reason for that and it certainly interested me and I hope other people.

A health scare

In early 1978, you were diagnosed with lung cancer. And you’d been smoking from a very early age.

I had. I took up smoking at university, as a student, and I had been smoking quite heavily. I was smoking a lot of roll-your-owns and pipe smoking. In 1978, I’d been in a car accident and they looked at my lungs amongst other things and found this patch of what looked very suspicious indeed. So the local radiographer told my GP, and he was very concerned and sent me off to St Vincent’s Hospital in Sydney. The head thoracic surgeon there was equally concerned and said, ‘The only way to deal with this is to have a lung out.’ So they had me on the operating theatre table, ready to go, and I was put under anaesthetic. I woke up from the anaesthetic and I still had my lung. The surgeon explained that they’d had a last minute look and found that the lesion had disappeared. In fact, it was a lesion caused not by cancer at all but by a partial collapse of the lung from being thrown against the seat belt in the car when the accident occurred.

I was greatly relieved, as you may imagine, and it’s coloured my whole attitude to life, having had a scare like that. I stopped smoking, of course. The surgeon described to me the horrible condition which my lungs were in. He’d been looking with the remote vision thing at the lesion and he didn’t see the lesion but he saw a pretty nasty collection of corrosion in my lungs from smoking. So I gave up that completely—and I didn’t have any difficulty in giving it up. I didn’t want to get lung cancer; I’d been near enough to that. So my lungs have been in a good state ever since. But it did alter my views on life generally.

“Retirement” and life outside of science

You retired at the end of 1979 from your professorship.

I decided in some ways that I didn’t want to be spending all my life just doing the same thing—not that I had any great plans to do anything else. I didn’t want to finish up being a senior administrator or somebody writing the history of science, which I knew very little about and didn’t feel like writing. So I retired and just went on pottering about, doing some more measurements of the same sort to keep me out of mischief for about another 10 years. Then I really did totally retire and stopped doing chemistry altogether, and I went on with other activities like electronics and my computer and playing chess and playing bridge and the other things that have kept me quite happy since.

Perhaps you should say a few words about Jean and your three daughters.

Jean was an enormous part of my life, as you can imagine, and we worked together for many years on all sorts of problems, even after we came to Armidale. She wasn’t able to work with me in England, but she certainly worked with me in Perth. The two children went with us to England and we had a third one in England, Jenny, the youngest one. As soon as we got back to Perth, things were a bit busy and she just couldn’t help me much. When we came to Armidale, the children got bigger and went to school, and she came back to give me all sorts of assistance in the lab. There were a number of joint papers published with her in Armidale, including that one I mentioned with Loren Hepler.

Diffusiometer at the University of Wisconsin, 1965.

We went to America, to Wisconsin, on a Fulbright Fellowship in 1965 and I stayed on into 1966, and she was giving me invaluable help there. For one thing, she was typing up papers for me, which was always a great help because a lot of people couldn’t read my writing; also she helped me quite a lot in the lab there. I was at a place called the Enzyme Institute in the University of Wisconsin at Madison. It’s not that I know anything about enzymes or biological things generally, but there was a man there, Lou Gosting, who was making a huge and very elaborate optical diffusion apparatus, in order to study mixtures of more than just two components, mixtures with two solutes in a liquid, usually water. This was deemed to be of biological interest and so he was doing these measurements there.

The idea of the relevance of diffusion measurements to biological things is partly of course that you get diffusion across synaptic junctions in nerve systems. That’s ultimately a diffusion-controlled reaction but on a very small scale so it goes pretty fast. But also it was a means of getting at the molecular weight and the dimensions, roughly, of some very large polymer molecules; it is difficult to get these things in other ways and it certainly has contributed something to that.

Anyway, he was building this apparatus but it wasn’t finished, and I hoped it would be while I was there but it was not. So we did other things, including some freezing point measurements on urea solutions because I was interested in the association problem; and Jean helped me with those. These involved some rather extreme weather conditions. They had a cold room at zero Fahrenheit and they had another cold room at zero Celsius and the room at zero Fahrenheit was really cold. In order to avoid heat losses in the freezing point measurements, we decided we would simply work in the room which was at zero Celsius, so we were close to the freezing point all the time and minimised the heat losses. But working in a room at zero Celsius is not entirely pleasant and we shivered, but we got the work finished. Jean was helping me in that lab and she was very worried when I had to go occasionally into the zero Fahrenheit room to get samples of stuff that I wanted to use for seeding. She was very concerned that I would get shut up in there, but I didn’t.

After we came back from Madison, she didn’t go on with any more research work. She felt that she was unable to keep up any more, so she went and used her chemical knowledge in making beautiful pots and became an extremely skilled potter, particularly in making very beautiful glazes. Lots of her friends have got samples of her work and there are quite a lot around this house, and a large amount was sold. It’s not often that you can have a hobby that you can actually recover your losses on by selling things. So that was very nice aspect of her life.

She died at the end of 2003 ultimately from a heart attack, but she’d been going downhill with Alzheimer’s for some months and I’d been nursing her rather concernedly in those last years. We had three daughters, who are all still with us. In fact, two of my daughters are retired now—it makes me feel old—and the youngest one is not very far from it. But none of them were scientists. They all were madly interested in books and literature and all did degrees in that area. Two of them became librarians and the other one became an archivist. There are four grandchildren and I’m expecting that the scientific gene will pop up again in due course.

Advice to young scientists

Do you have anything to say finally as words of advice for budding scientists?

Experiences I have had during my life have made me think that one of the best pieces of advice you could give to anybody in this field is: if you think you’ve got some strange results, don’t start theorising as to why this could happen; first, go over every detail of your calculations with great care and make sure that you really have got this effect before you say anything about it. Check your results very carefully before you commit yourself to saying anything in public. A lot of people could have benefited by this advice.

Thank you, Robin, for this very interesting interview. We wish you all the best in the future; thank you very much again.

Well, thank you, Ken. We’ve been associated for well over 40 years now, haven’t we, and I’m considerably in your debt for many reasons. Thank you.

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