Well, of course I have to mention that as well as the research work that I’ve just been talking about, Ray and I decided to go to some other lectures. And the one that stands out pre-eminently in my mind, and I’m sure in Ray’s, was... we attended a course on quantum mechanics by Dirac, Paul Dirac, an eminent theoretical physicist, an other-worldly character in many ways but a superb lecturer.

And our technique was the following: Dirac gave two or three lectures a week for two terms so it was a long lecture course, and he lectured sticking very closely to his famous textbook Quantum Mechanics. So we bought a copy of the textbook and listened to what Dirac had to say. He was masterly at putting his ideas across; everything that he said sounded eminently right. And it was of course couched in fairly difficult mathematics – at least, difficult for us. We had both been through pure mathematics third year at Melbourne whilst we were doing a Master’s degree, so we did have quite a good mathematical background, but Dirac was definitely the next stage as far as we were concerned. And we, I think, calculated at one stage that for every one hour of Paul Dirac’s lectures we spent three hours back in our rooms in college going through what he actually meant, and what it meant, and whether we understood it.

So it was a big intellectual effort on our part, but it also taught me, I think, that whilst I learnt a lot from it, that would not be a direction that I would want to go in my research. At one stage I had thought maybe I’d do theoretical chemistry rather than practical chemistry – I realised that it would be better for me to be a practical chemist who had a good theoretical background rather than to attempt to try and advance the theory. So it was a very stimulating and productive course of lectures from that point of view.