Money is a commodity that serves as a general medium of exchange; its exchanges therefore permeate the economic system. Like all commodities, it has a market demand and a market supply, although its special situation lends it many unique features. We saw in chapter 4 that its “price” has no unique expression on the market. Other commodities are all expressible in terms of units of money and therefore have uniquely identifiable prices.

The purchasing power of money is therefore determined by two factors: the total demand schedule for money to hold and the stock of money in existence. It is easy to see on a diagram what happens when either of these determining elements changes. Thus, suppose that the schedule of total demand increases (shifts to the right). Then (see Figure 75) the total-demand-for-money curve has shifted from DtDt to Dt′Dt′. At the previous equilibrium PPM point, A, the demand for money now exceeds the stock available by AE.

In the case of consumers’ goods, we do not go behind their subjective utilities on people’s value scales to investigate why they were preferred; economics must stop once the ranking has been made. In the case of money, however, we are confronted with a different problem. For the utility of money (setting aside the nonmonetary use of the money commodity) depends solely on its prospective use as the general medium of exchange.

A change in the money relation necessarily involves gains and losses because money is not neutral and price changes do not take place simultaneously. Let us assume—and this will rarely hold in practice—that the final equilibrium position resulting from a change in the money relation is the same in all respects (including relative prices, individual values, etc.) as the previous equilibrium, except for the change in the purchasing power of money. Actually, as we shall see, there will almost undoubtedly be many changes in these factors in the new equilibrium situation.

We are now in a position to draw together all the strands determining the prices of goods. In chapters 4 through 9 we analyzed all the determinants of the prices of particular goods. In this chapter we have analyzed the determination of the purchasing power of money. Now we can see how both sets of determinants blend together.

The price of any commodity tends to be the same throughout the entire area using it. We have seen that this rule is not violated by the fact that cotton in Georgia, for example, is priced lower than cotton in New York. When cotton in New York is a consumers’ good, cotton in Georgia is a capital good in relation to the former. Cotton in Georgia is not the same commodity as cotton in New York because goods must first be processed in one location and then transported to the places where they are consumed.

Clearing is particularly appropriate for interlocal transactions, since costs of transporting money from one locale to another are likely to be heavy. Bills of exchange on each town (i.e., I.O.U.’s owed by each town) can be reciprocally canceled. Suppose that there are two traders, A and B, in Detroit, and two in Rochester, C and D. A sells C a refrigerator for 200 gold grams, and D sells B a TV set for 200 grams. The two debts can be cleared, and no money need be shipped from one place to the other. On the other hand, D’s sale of a TV set may total 120 grams.