Abrasion

In numismatics , the ‘wear and tear,’ or waste of the substance of coins, in the pocket and circulation. It forms a large item in the expense of a metallic currency. The means employed to obviate, or to reduce it, consist in either alloying the metal to render it tougher and harder, or raising the borders so as to le en the surface exposed to friction. In well-formed coin both methods are adopted.