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 Networks Discover the Networks Discover the Networks (originally Discover the Network) (DtN) is a website run by the David Horowitz Freedom Center that focuses on the individuals, groups, and history of groups alleged to be politically left wing. DtN was launched in 2004 and has a staff of about a dozen contributors. Its current Editor-in-Chief is David Horowitz; John Perazzo is the project's managing editor, and Richard Poe is its investigative editor. Discover the Networks is associated with FrontPageMag.com. According to the project's mission statement, DtN's goal is to provide a comprehensive "guide to the political left" covering "the individuals and