Where did the saying Cold hard cash come from?

The phrase "cold hard cash" was coined by merchants and traders who were used to handling coins that, because they had a high gold and silver content, were warm and soft and did not wear very well. When more durable metals came into use it was generally noticed that they were cold and hard. In the cut and thrust of commerce a lot of transactions rely on the use of cheques and various forms of credit. Where these are not favoured the phrase "cold hard cash" applies to both coins and notes which are immediately available, or ready, as a form of payment.