When the exchange between two places, such as London and Paris, is at par, it is said to be a sign that the debts due from London to Paris are compensated by those due from Paris to London. On the contrary, when a premium is paid at London for a bill upon Paris, it is said to be a sign that the debts due from London to Paris are not compensated by those due from Paris to London, but that a balance in money must be sent out from the latter place; for the risk, trouble, and expense of exporting which, the premium is both demanded and given. But the ordinary state of debt and credit between those two cities must necessarily be regulated, it is said, by the ordinary course of their dealings with one another. When neither of them imports from the other to a greater amount than it exports to that other, the debts and credits of each may compensate one another. But when one of them imports from the other to a greater value than it exports to that other, the former necessarily becomes indebted to the latter in a greater sum than the latter becomes indebted to it: the debts and credits of each do not compensate one another, and money must be sent out from that place of which the debts overbalance the credits. The ordinary course of exchange, therefore, being an indication of the ordinary state of debt and credit between two places, must likewise be an indication of the ordinary course of their exports and imports, as these necessarily regulate that state.
But though the ordinary course of exchange should be allowed to be a sufficient indication of the ordinary state of debt and credit between any two places, it would not from thence follow, that the balance of trade was in favour of that place which had the ordinary state of debt and credit in its favour. The ordinary state of debt and credit between any two places is not always entirely regulated by the ordinary course of their dealings with one another; but is often influenced by that of the dealings of either with many other places. If it is usual, for example, for the merchants of England to pay for the goods which they buy of Hamburg, Danzig, Riga, etc. by bills upon Holland, the ordinary state of debt and credit between England and Holland will not be regulated entirely by the ordinary