Polonium were marketed by Firestone from 1940 to 1953. While the amount of radiation from the plugs was minuscule and not a threat to the consumer, the benefits of such plugs quickly diminished after approximately a month because of polonium's short half-life and because buildup on the conductors would block the radiation that improved engine performance. (The premise behind the polonium spark plug, as well as Alfred Matthew Hubbard's prototype radium plug that preceded it, was that the radiation would improve ionization of the fuel in the cylinder and thus allow the motor to fire more quickly and efficiently.) Polonium is
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