The fact that a number of sales take place simultaneously, and side by side, limits the extent to which coin can be replaced by the rapidity of currency. On the other hand, this fact is a new lever in economising the means of payment. In proportion as payments are concentrated at one spot, special institutions and methods are developed for their liquidation. Such in the middle ages were the virements at Lyons. The debts due to A from B, to B from C, to C from A, and so on, have only to be confronted with each other, in order to annul each other to a certain extent like positive and negative quantities. There thus remains only a single balance to pay. The greater the amount of the payments concentrated, the less is this balance relatively to that amount, and the less is the mass of the means of payment in circulation.

The function of money as the means of payment implies a contradiction without a terminus medius. In so far as the payments balance one another, money functions only ideally as money of account, as a measure of value. In so far as actual payments have to be made, money does not serve as a circulating medium, as a mere transient agent in the interchange of products, but as the individual incarnation of social labour, as the independent form of existence of exchange-value, as the universal commodity. This contradiction comes to a head in those phases of industrial and commercial crises which are known as monetary crises.⁴⁹ Such a crisis occurs only where the ever-lengthening chain of payments, and an artificial system of settling them, has been fully developed. Whenever there is a general and extensive disturbance of this mechanism, no matter what its cause, money becomes suddenly and immediately transformed, from its merely ideal shape of money of account, into hard cash. Profane commodities can no longer replace it. The use-value of commodities becomes valueless, and their value vanishes in the presence of its own independent form. On the eve of the crisis, the bourgeois, with the self-sufficiency that springs from intoxicating prosperity, declares money to be a vain imagination. Commodities alone are money. But now the cry is everywhere: money alone is a commodity! As the hart pants after fresh water, so pants his soul after money, the only wealth.⁵⁰ In a crisis, the antithesis between commodities and their value-form, money, becomes heightened into an absolute contradiction. Hence, in such events, the form under which money appears is of no importance. The money famine continues, whether payments have to be made in gold or in credit money such as bank-notes.⁵¹

If we now consider the sum total of the money current during a given period, we shall find that, given the rapidity of currency of the circulating medium and of the means of payment, it is equal to the sum of the prices to be realised, plus the sum of the payments falling due, minus the payments that balance each other, minus finally the number of circuits in which the same piece of coin serves in turn as means of circulation and of payment. Hence, even when prices, rapidity of currency, and the extent of the economy in payments, are given, the quantity of money current and the mass of commodities circulating during a given period, such as a day, no longer correspond. Money that represents commodities long withdrawn from circulation, continues to be current. Commodities circulate, whose equivalent in money will not appear on the scene till some future day. Moreover, the debts contracted each day, and the payments falling due on the same day, are quite incommensurable quantities.⁵²

Credit-money springs directly out of the function of money as a means of payment. Certificates of the debts owing for the purchased commodities circulate for the purpose of transferring those debts to others. On the other hand, to the same extent as the system of credit is extended, so is the function of money as a means of payment. In that character it takes various forms peculiar to itself under which it makes itself at home in the sphere of great commercial transactions. Gold and silver coin, on the other hand, are mostly relegated to the sphere of retail trade.⁵³

        
Receipts.                         Payments.  ———————————————————————————————-  Bankers' and
Merchants'              Bills payable after              Bills payable after   date,                 L533,596   date                   L302,674                                      Cheques on Bankers,
&c.           Cheques on London   payable on demand      357,715    Bankers                663,672    Country Notes             9,627     Bank of
England Notes    68,554   Bank of England Notes    22,743  Gold                     28,089   Gold                      9,427  Silver and Copper         1,486  
Silver and Copper         1,484  Post Office Orders          933  ———————————————-   ———————————————-
              Total   L1,000,000                Total   L1,000,000   "Report from the Select Committee on the Bank
Acts, July, 1858," p. lxxi.