In the Summer of 1944 G.T. Seaborg, R. A. James and A. Ghiorso, working at the Manhattan Project, performed a careful chemical fractionation on a sample of plutonium which had been irradiated with 32 MeV helium ions at the University of California. A new radioactive isotope was found, which emitted 4.7 MeV alpha particles and was chemically separable from neptunium and plutonium. Both nuclear and chemical evidence indicated that the activity could be ascribed to an isotope of a new element with atomic number 96. In tribute to the brilliant pioneering achievements of Pierre and Marie Curie in the field of radioactivity the new element was given the name curium.