Radium seventh of a gram of radium. One kilogram of the Earth's crust contains about 900 picograms of radium, and one liter of sea water contains about 89 femtograms of radium. Radium was discovered by Marie Sklodowska-Curie and her husband Pierre Curie on 21 December 1898, in a uraninite (pitchblende) sample. While studying the mineral earlier, the Curies removed uranium from it and found that the remaining material was still radioactive. They separated out an element similar to bismuth from pitchblende in July 1898, that turned out to be polonium. They then separated out a radioactive mixture consisting mostly of two
Discover Card card was used. A 1989 study found that Discover had strong consumer adoption in the U.S.; the number of households with Discover cards increased by 2.1 million, or 14 percent, in 1989. Discover was also noteworthy for being the only credit card accepted by the U.S. Customs Service to pay customs duty, effective Feb. 19, 1987. Since it did not charge a percentage fee to retailers, unlike Visa, MasterCard, and American Express, Discover was also the only credit card accepted at Sam's Club; the retailer has since started to accept MasterCard and American Express (see below). The plan to create