But Heisenberg did another thing for me, he called me in, not much after I arrived, he said- Here are two papers, one by a Dane, one by an American. They are both about the hydrogen molecular ion. Two hydrogen nuclei, two protons, and one electron moving round both of them. The Dane, Buro, I think, was his name, Buro found the solution. The American has proved that Buro is wrong and no solution exists. Who is right? Well, on that one I did well. I went away, read the two papers, and in two days I was back and told Heisenberg in detail why the American objections were wrong. The American postulated a particularly simple behavior of the electrons when they got to- get very far away, at infinity. If you give this in a reasonable way, you got Buro's result. All right, says Heisenberg- that is the lower state of the hydrogen molecule ion, and you say it's correct. Now calculate all the other states. That was the origin of my PhD thesis: "The energy states of the hydrogen molecular ion". I can tell you, I couldn't do it. Nobody else did. Not in the form of definite known formulae. I could do it numerically, using a computing machine. Well, you know, what am I talking about? I am talking about the year 1929. The computing machines were sizable. They had a handle which you could turn and if you turned the handle, you made a lot of noise and you got one number out of it. In the meantime, as you all know, the computers made a little progress. But there I was, you know, not liking to get up early in the morning, I got in late. Each night I was turning the handle and got more and more of the excited states of the hydrogen molecular ion. Now, all this is relevant, because Heisenberg, at that time unmarried, tried, not always effectively, not always successfully, to sleep in the room right above the one where I turned the machine. So I noticed - I did not know it at that time - but I noticed that Heisenberg would come down and started to chat with me. And those were very amusing, very interesting conversations. I remember one when I had to contradict Heisenberg. He said- Now everything is done in physics, what will I do next? I sort of said, not quite in these words- Damn it, aren't you satisfied? And he said to that, very explicitly- No. I think I'll go into music. Well, on another occasion, he came down and asked- When we will be through? I said- I think in one or two years I could finish it. Heisenberg said- I really think you have done enough. I think these are nice results. Just write them up and it will make a good thesis. Now look, I very clearly claim that I got my Doctor's degree because I did not let Heisenberg sleep. I wrote it up, it was published, my first publication. In spite of what I'm saying- what I said, I am even slightly proud of it, not very proud. But I didn't have my Doctor's yet, and that is another story I want to tell you.