Unlike Röntgen's discovery, which was the object of widespread curiosity from scientists and lay people alike for the ability of X-rays to make visible the bones within the human body, Becquerel's discovery made little impact at the time, and Becquerel himself soon moved on to other research. Marie Curie tested samples of as many elements and minerals as she could find for signs of Becquerel rays, and in April 1898 also found them in thorium. She gave the phenomenon the name "radioactivity". Along with Pierre Curie and Gustave Bémont, she began investigating pitchblende, a uranium-bearing ore, which was found to be more radioactive than the uranium it contained. This indicated the existence of additional radioactive elements. One was chemically akin to bismuth, but strongly radioactive, and in July 1898 they published a paper in which they concluded that it was a new element, which they named " polonium ". The other was chemically like barium, and in a December 1898 paper they announced the discovery of a second hitherto unknown element, which they called " radium ". Convincing the scientific community was another matter. Separating radium from the barium in the ore proved very difficult. It took three years for them to produce a tenth of a gram of radium chloride, and they never did manage to isolate polonium.