http://www.urbandictionary.com/define.php?term=black beauties
Black Beauties (also known as Black Birds or Black Bombers) are a combination of Amphetamine (Speed) and Dextroamphetamine (Active salt in Adderall). Pills are typically 20 milligrams. Effects include a mild to moderate euphoria, increased hyperactivity, increased awareness of surroundings, increased interest in repetitive or normally boring activities (
like Charlie Watts' drumming), decreased appetite, and decreased ability to sleep. The added dextroamphetamine reduces comedown effects compared to amphetamine alone, but not to the extent of methamphetamine.
Black beauties were the drug of choice for truck drivers during the late 60's and early 70's, prior to the advent of methamphetamine. Methamphetamine became popular because drivers had the ability to sleep after the drug's effects wore off.