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Dr. Millikan had reserved his remarks for an appropriate occasion, the International Conference on Physics. The roster of those assembled was studded with names famed the world over. Present and greeted with stormy applause were quiet, brilliant Jean Frédéric Joliot and Irene Curie-Joliot, son-in-law and daughter of the late Marie Sklodowska Curie. A vast and totally unforeseen field of research was opened last year when the Curie-Joliots discovered the phenomenon of artificial radioactivity. The young couple obtained a continued emission of positrons from boron, magnesium and aluminum by bombarding those elements with alpha particles (TIME, Feb. 12). Since then their results have been reproduced and extended in dozens of laboratories in a half-dozen countries, notably England, Italy, the U. S. Italy's Professor Enrico Fermi and his aids have coaxed radiations of beta particles (fast electrons) from phosphorus, iron, silicon, aluminum, chlorine, vanadium, copper, arsenic, silver, tellurium, iodine, chromium, barium, fluorine, sodium, magnesium, titanium, zirconium, zinc, strontium, antimony, selenium, bromine.
Last week the Curie-Joliots proposed for elements made artificially radioactive such names as radio-nitrogen, radio-aluminum, radio-silicon. They foresaw the use in cancer therapy of packets of artificial radio-elements, which, because they disintegrate as the radiation dwindles, would not have to be withdrawn from the body after treatment as radium seeds must be. They told of experiments presaging the production of a radio-phosphorus which would emit neutrons (emitted by no natural radioactive substance). And they spoke of work indicating the existence of the neutrino, an ultimate particle lacking electrical charge like the neutron, but small in mass like the electron. Many a physicist has held the neutrino's existence called for on theoretical grounds, has hesitated to sign its birth certificate because it eludes experimental observation.