Page 175. " Fetch ahead for the doubloons. "
Spanish gold doubloon stamped as minted in 1798 (slightly after the setting of Treasure Island)
Public DomainSpanish gold doubloon stamped as minted in 1798 (slightly after the time period represented in Treasure Island)
Doubloons were minted in  Spain, Mexico, Peru, and Nueva Granada and were in currency up until the mid-nineteenth century. They were possibly so called because they featured a double portrait of Ferdinand and Isabella. The doubloon was the coin upon which many other European gold coins were modelled.