A more thorough explanation:

Goldsmiths' notes were cash notes or promissory notes given by bankers to customers as acknowledgments of the receipt of money. This term originated from the London banking business, which was initially conducted by goldsmiths.

• John deposited £100 with his local bank and received a goldsmiths' note as proof of his deposit.
• Mary needed to pay her rent but didn't have cash on hand, so she withdrew money from her bank and received a goldsmiths' note as proof of her withdrawal.

These examples illustrate how goldsmiths' notes were used as proof of transactions between customers and their banks. They were given to customers as a receipt of their deposit or withdrawal and could be used as evidence of the transaction if needed.