Robert Gordon Sproul, who became university president the day after Lawrence became a professor, was a member of the Bohemian Club, and he sponsored Lawrence's membership in 1932. Through this club, Lawrence met William Henry Crocker, Edwin Pauley, and John Francis Neylan. They were influential men who helped him obtain money for his energetic nuclear particle investigations. There was great hope for medical uses to come from the development of particle physics, and this led to much of the early funding for advances Lawrence was able to obtain. While at Yale, Lawrence met Mary Kimberly (Molly) Blumer, the eldest of four daughters of George Blumer, the dean of the Yale School of Medicine. They first met in 1926 and became engaged in 1931, and were married on May 14, 1932, at Trinity Church on the Green in New Haven, Connecticut. They had six children: Eric, Margaret, Mary, Robert, Barbara, and Susan. Lawrence named his son Robert after theoretical physicist Robert Oppenheimer, his closest friend in Berkeley. In 1941, Molly's sister Elsie married Edwin McMillan, who would go on to win the Nobel Prize in Chemistry in 1951. Development of the cyclotron Invention The invention that brought Lawrence to international fame started out as a sketch on a scrap of a paper napkin. While sitting in the library one evening in 1929, Lawrence glanced over a journal article by Rolf Widerøe, and was intrigued by one of the diagrams. This depicted a device that produced high-energy particles by means of a succession of small "pushes". The device depicted was laid out in a straight line using increasingly longer electrodes. At the time, physicists were beginning to explore the atomic nucleus. In 1919, the New Zealand physicist Ernest Rutherford had fired alpha particles into nitrogen and had succeeded in knocking protons out of some of the nuclei. But nuclei have a positive charge that repels other positively charged nuclei, and they are bound together tightly by a force that physicists were only just beginning to understand. To break them up, to disintegrate them, would require much higher energies, of the order of millions of volts. Lawrence saw that such a particle accelerator would soon become too long and unwieldy for his university laboratory. In pondering a way to make the accelerator more compact, Lawrence decided to set a circular accelerating chamber between the poles of an electromagnet. The magnetic field would hold