Scientist. He was credited with the discovery of Uranium-238, a compound that was vital to the construction of the atom bomb. Attended the schools of the city of Toronto, Canada, excelled in his studies finishing in the top two of virtually every competition he entered. He attended the University of Toronto, graduating in 1909 with a bachelor's degree and in 1910 with a master's degree. By 1911 he had his first article published in the "Journal of the Royal Astronomical Society of Canada" and later in 1911 he went to Germany for additional and advanced studies spending three years in his pursuits. He attended the University of Munich and Gottingen, as well as the University of Wurzburg. Due to the beginning of World War I he was forced to leave Germany and enrolled at the University of Chicago in late 1914. By 1916 he received a doctorate in physics with the grade of summa cum laude, which at the time only one other student had achieved. He served with the Canadian Army Signal Corps during World War I and after the war returned to the University of Chicago, remaining there until his death. His work included the study of the properties of positive rays, or canal rays which were also described as positively charged atoms or molecules set into motion at high speed through the use of electric fields. His work and theories were thought to be a precursor of the modern mass spectrograph. His discovery of the element Uranium-238 would prove to be a key to the construction of the first atomic bomb during World War II. His contributions to physics were recognized by numerous awards including his election to the National Academy of Sciences in 1937, and in 1944 he became the President of the American Physical Society. He was regarded as the principal authority on positive rays and made extensive studies of the passage of protons thru helium, in which he made the discovery that protons go right thru helium without being appreciably deflected. At the time of his death he was Professor of Physics in the Division of the Physical Sciences of the University of Chicago, and Director of the Argonne National Laboratory's Division of Mass Spectroscopy and Crystallography.