E. Cobham Brewer 18101897. Dictionary of Phrase and Fable. 1898.
Ringing the Changes.
A method of swindling by changing gold and silver in payment of goods. For example: A man goes to a tavern and asks for two-pennyworth of whisky. He lays on the counter half a sovereign, and receives nine shillings and tenpence in change. Oh! (says the man) give me the half-sovereign back, I have such a lot of change. He then takes up ten shillings in silver and receives back the half-sovereign. The barmaid is about to take up the silver when the man says, Give me a sovereign in lieu of this half-sovereign and ten shillingsworth of silver. This is done, and, of course, the barmaid loses ten shillings by the transaction.