We have seen that a change in the values of gold and silver does not affect their function as measures of value or money of account. But this change is of decisive importance for money as a hoard, since with the rise or fall of value of gold and silver, the total value of a gold or silver hoard will also rise or fall. Of still greater importance is the effect of this change on money as a means of payment. The payment takes place after the sale of the commodity, or the money serves in two different capacities at two different periods; first, as a measure of value, then as a means of payment corresponding to the measurement. If, during this interval, the value of the precious metals or the labor-time necessary for their production undergoes a change, the same quantity of gold or silver will be worth more or less when it appears as a means of payment than what it was when it served as a measure of value, i. e., when the contract was concluded. The function of a particular commodity, like gold or silver, to serve as money or independent exchange value comes here in conflict with the nature of the particular commodity whose magnitude of value depends on changes in the cost of its production. The great social revolution which caused the fall in value of the precious metals in Europe, is as well known as the revolution of an opposite character which had been brought about at an early period in the history of the ancient Roman republic by the rise in value of copper in terms of which the debts of the plebeians had been contracted. Without attempting here to follow any further the fluctuations of value of the precious metals and their effect on the system of bourgeois political economy, it is at once apparent that a fall in the value of the precious metals favors the debtors at the expense of the creditors, while a rise in their value favors the creditors at the expense of the debtors. c. WORLD MONEY. Gold becomes money as distinguished from coin only after it is withdrawn from circulation in the shape of a hoard; it then enters circulation as a non-medium of circulation, and finally breaks through the barriers of home circulation to assume the part of a universal equivalent in the world of commodities. It becomes _world money_.