I was quite free to travel as I liked; I got an amount of money which I used sparingly so as to spin out the fellowship as long as possible. I started in Cambridge; I spent a couple of weeks in Cambridge. I saw the Cavendish Laboratory there; I met some of the younger people, but I looked around more to imbibe the atmosphere of Cambridge. Then I went to Leiden. There I knew Ehrenfest, and I simply dropped in. And at that time Goudsmit was there. He was working partly in Leiden and partly in Amsterdam. He was, I think, assistant of Professor Zeeman and did some work with Zeeman, and the rest of the time be spent in Leiden. And there was a physicist, Dieke, who is now at Johns Hopkins University who was interested in band spectra. Then there was Fermi; he was stopping in Leiden for some time on some Italian fellowship. And then there was a young man, Tinbergen, who was doubting whether he should go into physics or into economics; he finally decided to go into economics, and he is now our economical expert of our government here in Holland. So they all made good. That's where I first met Fermi; we stayed at the same pension. There was room at the pension where Fermi was staying, so I stopped there too, and we got rather well-acquainted then. Fermi, of course, was quite unknown; he was 23 or so - and he had not yet done important things. Interview with Dr. Ralph Kronig By John L. Heilbron, November 12, 1962 http://www.aip.org/history/ohilist/4721.html