Compton (left) and his assistant, Richard Doan, look over equipment that Compton built for recording the intensity of cosmic rays in the stratosphere. The equipment will be carried into the stratosphere on a balloon and the measurements will be transmitted to the ground by radio. Arthur Holly Compton (September 10, 1892 - March 15, 1962) was an American physicist. In 1919, Compton was awarded a National Research Council Fellowship that allowed students to study abroad. He chose the Cavendish Laboratory in England, where he studied the scattering and absorption of gamma rays which led to the discovery of the Compton effect. He used X-rays to investigate ferromagnetism, concluding that it was a result of the alignment of electron spins, and studied cosmic rays, discovering that they were made up principally of positively charged particles. He won the Nobel Prize in Physics in 1927 for his discovery. During WWII, he was a key figure in the Manhattan Project that developed the first nuclear weapons. After the war, Compton became Chancellor of Washington University in St. Louis. During his tenure, the university formally desegregated its undergraduate divisions, named its first female full professor, and enrolled a record number of students after wartime veterans returned to the United States. He died in 1962 from a cerebral hemorrhage at the age of 69.