There's no mention of "gold". It says on this here piece of paper: "I promise to pay the bearer on demand the sum of twenty pounds". The implication that this

There's no mention of "gold". It says on this here piece of paper: "I promise to pay the bearer on demand the sum of twenty pounds". The implication that this £20 note is not actually £20. But ten £2 coins is coin-of-the-realm, and coin is what you can expect the Governor to hand over when you go to cash-in the promise.