Now, as was said a little while ago, perhaps the central function in banking is for the banker to receive his customer's money and also his credits falling due, and to render to him in return for these _a credit_, that is, a right to demand from himself an equal sum at a future time or times. The evidence of this right is entered on the banker's books, and usually too on the customer's passbook, and thus becomes what is called a DEPOSIT. The ownership of the money and of the credits deposited passes over completely from the customer to the banker. It is a complete case of buying and selling to the mutual profit of the parties. The banker has the right to do just what he pleases with his deposits, and the customer has a right to draw cheques on his credit as and when he pleases; only the banker's entry of the transaction on his books is a virtual and a legal _promise_ to pay that amount to his customer, and therefore he must be ready to respond to his customer's call, whenever the latter demands, not his own money, but so much of his banker's money. _A deposit, accordingly, is not the very thing deposited, but a credit._ It is the banker's promise and the depositor's property. It is in this way that a banker buys ready money with a credit. The motive, then, that leads the depositor to intrust his money to the banker is the desire, not to have that specific money kept safely for him, for he lost possession of it absolutely when it passed the counter, he _sold_ it and took his pay in something else, but rather to have the unquestioned right to call on the banker for such sums (not to exceed the deposit in the aggregate) and at such times as may suit his own convenience. He has such confidence in the integrity and solvency of the banker, finds it so practically convenient to have dealings with him, and comes to have certain minor privileges at the bank in other relations over non-depositors, that he quite prefers a credit on the banker to the possession of the money itself. The corresponding motive of the banker to receive his customer's funds on these terms is that he finds by experience (his own and others'), that he can safely use a large portion of these moneys deposited in other operations in credit profitable to himself, and at the same time be practically sure of meeting all his customer's calls for money as they are made. Every good banker finds out, that many of his customers wish always to leave a balance in his hands; that while some of them are constantly drawing cheques on him for cash, others of them are as constantly depositing with him in cash; and that consequently he can properly and safely use a large part of the money he has purchased with his credit to purchase other credits with. Deposit-banking, therefore, is not only convenient and profitable for the depositor, but also excellent and profitable for the banker.