Refunding Certificates were banknotes issued by the United States Treasury in 1879 which originally promised to pay 4% annual interest in perpetuity. Depicting Benjamin Franklin, they were issued only in the $10 denomination. The issuance of these certificates reflects the end of a coin-hoarding period that began during the American Civil War, and represented a return to public confidence in paper money.Banknote: United States Treasury; image courtesy of the National Numismatic Collection at the Smithsonian Institution