It is, therefore, easy to explain how the mass of securities held by a bank as collateral increases, hence how the growing demand for pecuniary accommodation can be satisfied by the bank, while the total mass of currency remains the same or decreases. This total mass is held in check during such periods of money stringency in two ways: 1) by a drain of gold; 2) by a demand for money in its capacity as a mere means of payment, when the issued bank-notes return immediately; or when the transactions take place without the mediation of notes by means of book credit; when, therefore, payments are made simply through a credit transaction, the settlement of these payments being the sole purpose of the operation. It is a peculiarity of money, when it serves merely to settle accounts (and in times of crises loans are taken up to pay, rather than to buy; to wind up previous transactions, not to initiate new ones), that its circulation is no more than fleeting, even where balances are not settled by mere credit operations, without the mediation of money, so that, when there is a strong demand for pecuniary accommodation, an enormous quantity of such transactions can take place without expanding the circulation. But the mere fact that the circulation of the Bank of England remains stable or even decreases simultaneously with an extensive accommodation of money on its part, does not prima facie prove, as Fullarton, Tooke and others assume (owing to their erroneous notion that pecuniary accommodation is identical with receiving capital on loan as additional capital), that the circulation of money (of bank-notes) in its function as a means of payment is not increased and extended. Since the circulation of notes as means of purchase decreases during a business depression, when such extensive accommodation is necessary, their circulation as means of payment may increase, and the aggregate amount of the circulation, the sum of notes functioning as means of purchase and payment, may remain stable or may even decrease. The circulation as a means of payment of bank-notes immediately returning to the bank that issues them is simply not circulation in the eyes of those economists.