When a bank discounts to a merchant a real bill of exchange drawn by a real creditor upon a real debtor, and which, as soon as it becomes due, is really paid by that debtor; it only advances to him a part of the value which he would otherwise be obliged to keep by him unemployed and in ready money for answering occasional demands. The payment of the bill, when it becomes due, replaces to the bank the value of what it had advanced, together with the interest. The coffers of the bank, so far as its dealings are confined to such customers, resemble a water pond, from which, though a stream is continually running out, yet another is continually running in, fully equal to that which runs out; so that, without any further care or attention, the pond keeps always equally, or very near equally full. Little or no expense can ever be necessary for replenishing the coffers of such a bank.
A merchant, without over-trading, may frequently have occasion for a sum of ready money, even when he has no bills to discount. When a bank, besides discounting his bills, advances him likewise upon such occasions, such sums upon his cash account, and accepts of a piece meal repayment as the money comes in from the occasional sale of his goods, upon the easy terms of the banking companies of Scotland; it dispenses him entirely from the necessity of keeping any part of his stock by him unemployed and in ready money for answering occasional demands. When such demands actually come upon him, he can answer them sufficiently from his cash account. The bank, however, in dealing with such customers, ought to observe with great attention, whether in the course of some short period (of four, five, six, or eight months, for example) the sum of the repayments which it commonly receives from