Underlying the whole business of foreign exchange is the way in which obligations between creditors in one country and debtors in another have come to be settled—‌by having the creditor draw a draft directly upon the debtor or upon some bank designated by him. A merchant in New York has sold a bill of goods to a merchant in London, having thus become his creditor, say, for $5,000. To get his money, the merchant in New York will, in the great majority of cases, draw a sterling draft upon the debtor in London for a little over £1,000. This draft his banker will readily enough convert for him into dollars. The buying and selling and discounting of countless such bills of exchange constitute the very foundation of the foreign exchange business.

Not all international obligations are settled by having the creditor draw direct on the debtor. Sometimes gold is actually sent in payment. Sometimes the debtor goes to a banker engaged in selling drafts on the city where the obligation exists, gets such a draft from him and sends that. But in the vast majority of cases payment is effected as stated—‌by a draft drawn directly on the buyer of the goods. John Smith in London owes me money. I draw on him for £100, take the draft around to my bank and sell it at, say, 4.86, getting for it a check for $486.00. I have my money, and I am out of the transaction.

Obligations continually arising in the course of trade and finance between firms in New York and firms in London, it follows that every day in New York there will be merchants with sterling drafts on London which they are anxious to sell for dollars, and vice versa. The supply of exchange, therefore, varies with the obligations of one country to another. If merchants in New York, for instance, have sold goods in quantity in London, a great many drafts on London will be drawn and offered for sale in the New York exchange market. The supply, it will of course be apparent, varies. Sometimes there are many drafts for sale; sometimes very few. When there are a great many drafts offering, their makers will naturally have to accept a lower rate of exchange than when the supply is light.

The par of exchange between any two countries is the price of the gold unit of one expressed in the money of the other. Take England and the United States. The gold unit of England is the pound sterling. What is the price of as much gold as there is in a new pound sterling, expressed in American money? $4.8665. That amount of dollars and cents at any United States assay office will buy exactly as much gold as there is contained in a new British pound sterling, or sovereign, as the actual coin itself is called. 4.8665 is the mint par of exchange between Great Britain and the United States.

The fact that the gold in a new British sovereign (or pound sterling) is worth $4.8665 in our money by no means proves, however, that drafts payable in pounds in London can always be bought or sold for $4.8665 per pound. To reduce the case to a unit basis, suppose that you owed one pound in London, and that, finding it difficult to buy a draft to send in payment, you elected to send actual gold. The amount of gold necessary to settle your debt would cost $4.8665, in addition to which you would have to pay all the expenses of remitting. It would be cheaper, therefore, to pay considerably more than $4.8665 for a one-pound draft, and you would probably bid up until somebody consented to sell you the draft you wanted.

Which goes to show that the mint par is not what governs the price at which drafts in pounds sterling can be bought, but that demand and supply are the controlling factors. There are exporters who have been shipping merchandise and selling foreign exchange against the shipments all their lives who have never even heard of a mint par of exchange. All they know is, that when exports are running large and bills in great quantity are being offered, bankers are willing to pay them only low rates—‌$4.83 or $4.84, perhaps, for the commercial bills they want to sell for dollars. Conversely, when exports are running light and bills drawn against shipments are scarce, bankers may be willing to pay 4.87 or 4.88 for them.

For a clear understanding of the mechanics of the exchange market there is necessary a clear understanding of what the various forms of obligations are which bring foreign exchange into existence. Practically all bills originate from one of the following causes:

1. Merchandise has been shipped and the shipper draws his draft on the buyer or on a bank abroad designated by him.

2. Securities have been sold abroad and the seller is drawing on the buyer for the purchase price.

3. Foreign money is being loaned in this market, the operation necessitating the drawing of drafts on the lender.

4. Finance-bills are being drawn, i.e., a banker abroad is allowing a banker here to draw on him in pounds sterling at 60 or 90 days' sight in order that the drawer of the drafts may sell them (for dollars) and use the proceeds until the drafts come due and have to be paid.

1. Looking at these sources of supply in the order in which they are given, it is apparent, first, what a vast amount of foreign exchange originates from the direct export of merchandise from this country. Exports for the period given below have been as follows: