Prior to the 1870s, both gold and silver were used as international means of payment and the exchange rates among currencies were determined by either their gold or silver contents. Suppose that the US dollar (USD) was pegged to gold at $28 per ounce, the French franc (FF) was pegged to gold at 82 francs per ounce and to silver at 30 francs per ounce, and the German mark (GM) was pegged to silver at 16 mark per ounce.