For a long time, the value of coins was equivalent to the amount they contain metal. In this regard, there was a problem - crooks cut small pieces of metal from the edges to make them into new coins. Addressing the proposed Isaac Newton, who was a part-time employee of the British Royal Mint. His idea was simple - cut the edges of the coins in small lines, for which stesannye edge would have been immediately noticeable. This part of the coins issued so to this day is called the edge.