Lennard-Jones was a theoretical chemist, and he was at that stage doing some world-shattering work on what is called molecular orbital theory. We needn't go in to that now, but I was interested in it because in fact theoretical chemistry did interest me. What I hadn't said earlier was that in my spare time I was doing... an MSc degree in Melbourne and being a tutor in Trinity College, I also attended some extra lectures and some of those were in pure mathematics; I actually got up, with Ray Martin, up to final – third-year – pure mathematics, so we did know a bit of mathematics; and I thought it would be useful to see if I could go to Lennard-Jones' lectures, and I learnt a lot from those. Later, as it transpired, I did a post-doctoral year with Lennard-Jones, and in the seminar then at the time was John Pople, whom you will recognise later. He went to America, got a Nobel Prize for his superb work not only in NMR but in theoretical chemistry.