I had the goal to explain the binding of nuclear matter entirely on the basis of experimental results in the interaction of two nucleons. And the interaction of two nucleons can be well investigated experimentally, which was done at Berkeley and other places. And one gets very complicated but very intricate results on this interaction, and it was my hope that I could explain on the basis of these experiments that nuclear matter is bound by 16 millions of electron volts per nucleon, and at the same time explain the density of nuclear matter. Well, I didn't succeed. I worked on this for many years. I had several graduate students, some good ones in this. The best one among them was John Negele who is now a professor at MIT and who already in his thesis managed to use nuclear matter theory to calculate the density distribution in a very heavy nucleus, namely in lead of... of mass 208. And this calculation was the... really the paradigm for further calculations of many other people and to everybody's satisfaction it was then possible to measure the distribution of charge in the nucleus lead 208, and it turned out that this was exactly as calculated by Negele. In addition to that, people afterwards were able to get the difference between the charge distribution in lead and the next higher nucleus, namely bismuth 209, and that gives you then insight into the wave function of one particular nucleon inside the nucleus. So this confirmed the principle of the.. of the calculation, namely that each nucleon has its own wave function inside the nucleus and then these nucleons interact to give you the whole.