The credit which we are now called upon to consider, as a distinct purchasing power, independent of money, is of course not credit in its simplest form, that of money lent by one person to another, and paid directly into his hands; for, when the borrower expends this in purchases, he makes the purchases with money, not credit, and exerts no purchasing power over and above that conferred by the money. The forms of credit which create purchasing power are those in which no money passes at the time, and very often none passes at all, the transaction being included with a mass of other transactions in an account, and nothing paid but a balance. This takes place in a variety of ways, which we shall proceed to examine, beginning, as is our custom, with the simplest. First: Suppose A and B to be two dealers, who have transactions with each other both as buyers and as sellers. A buys from B on credit. B does the like with respect to A. At the end of the year, the sum of A’s debts to B is set against the sum of B’s debts to A, and it is ascertained to which side a balance is due. This balance, which may be less than the amount of many of the transactions singly, and is necessarily less than the sum of the transactions, is all that is paid in money; and perhaps even this is not paid, but carried over in an account current to the next year. A single payment of a hundred pounds may in this manner suffice to liquidate a long series of transactions, some of them to the value of thousands. But, secondly: The debts of A to B may be paid without the intervention of money, even though there be no reciprocal debts of B to A. A may satisfy B by making over to him a debt due to himself from a third person, C. This is conveniently done by means of a written instrument, called a bill of exchange, which is, in fact, a transferable order by a creditor upon his debtor, and when _accepted_ by the debtor, that is, authenticated by his signature, becomes an acknowledgment of debt. § 4. Bills of Exchange. Bills of exchange were first introduced to save the expense and risk of transporting the precious metals from place to place. The trade between New York and Liverpool affords a constant illustration of the uses of a bill of exchange. Suppose that A in New York ships a cargo of wheat, worth $100,000, or £20,000, to B in Liverpool; also suppose that C in Liverpool (independently of the negotiations of A and B) ships, about the same time, a cargo of steel rails to D in New York, also worth £20,000. Without the use of bills of exchange, B would have been obliged to send £20,000 in gold across the Atlantic, and so would D, at the risk of loss to both. By the device of bills of exchange the goods are really bartered against each other, and all transmission of money saved. [Illustration.]