Pieces of eight
Spanish eight reales coins known as ‘pieces of eight’ were an international currency. Other countries made coins of about the same weight: such as the American dollar, the French five francs or the English crown. During the crisis of 1797 it was quicker to stamp George III’s portrait onto foreign coins than melt them down to make new ones.
A gold standard
By 1798, the Mint made high value gold coins such as guineas, but hardly any silver or copper coins. People often used portable scales to check their coin was the correct weight and not a forgery.