Rare Benjamin Franklin Printing Blocks Identified as Instruments Used to Print Colonial Currency

Three extremely rare 18th-century type-metal blocks on deposit with the Library Company of Philadelphia have been identified as the instruments used to print colonial currency in Delaware and beyond. The blocks were the output of Benjamin Franklin's printing office and represent a technological innovation—perhaps Franklin's only real invention of a technical advance in printing—only now fully understood for the first time.

The Delaware Country Institute of Science in Media, PA, recently found what appeared to be one of the leaf blocks used to print currency in their collection, along with two metal ornament blocks and some pieces of paper money.