Charles William Duncan , Jr. ( born September 9 , 1926 ) is an American entrepreneur , administrator , and statesman best known for serving as U.S. Secretary of Energy on the Cabinet of President Jimmy Carter from 1979 to 1981 .
Charles William Duncan , Jr. ( born September 9 , 1926 ) is an American entrepreneur , administrator , and statesman . Duncan served as the U.S. Secretary of Energy on the Cabinet of President Jimmy Carter from 1979 to 1981 .