Marie Curie doubt, the Curies sought to isolate polonium and radium in pure form. Pitchblende is a complex mineral; the chemical separation of its constituents was an arduous task. The discovery of polonium had been relatively easy; chemically it resembles the element bismuth, and polonium was the only bismuth-like substance in the ore. Radium, however, was more elusive; it is closely related chemically to barium, and pitchblende contains both elements. By 1898 the Curies had obtained traces of radium, but appreciable quantities, uncontaminated with barium, were still beyond reach. The Curies undertook the arduous task of separating out radium salt by differential
Discover: The World of Science Discover: The World of Science Discover: The World of Science is an American television show that ran between 1983 and 1990. Actor Peter Graves is the on-camera host and narrator of "Discover: The World of Science", a monthly, one-hour magazine-style television series which provides a human perspective on new developments in robots, science, technology, medicine, the environment, behavior and natural history. The series was typically broadcast on Wednesday evenings at 8 PM on PBS. The series, with early episodes being underwritten by Atari and later episodes being underwritten by GTE, was produced by Chedd-Angier Productions in association with Discover Magazine.