Polonium the Curies while they were investigating the cause of pitchblende radioactivity. Pitchblende, after removal of the radioactive elements uranium and thorium, was more radioactive than the uranium and thorium combined. This spurred the Curies to search for additional radioactive elements. They first separated out polonium from pitchblende in July 1898, and five months later, also isolated radium. German scientist Willy Marckwald successfully isolated 3 milligrams of polonium in 1902, though at the time he believed it was a new element, which he dubbed "radio-tellurium", and it was not until 1905 that it was demonstrated to be the same as polonium.
Discover Card Discover Card Discover is a credit card brand issued primarily in the United States. It was introduced by Sears in 1985. When launched, Discover did not charge an annual fee and offered a higher-than-normal credit limit, features that were disruptive to the existing credit card industry. A subsequent innovation was "Cashback Bonus" on purchases. Most cards with the Discover brand are issued by Discover Bank, formerly the Greenwood Trust Company. Discover transactions are processed through the Discover Network payment network. In 2005, Discover Financial Services acquired Pulse, an electronic funds transfer network, allowing it to market and issue debit and