This brings us to the markets for bills of exchange, the prices of which, like those of every other security, are settled by supply and demand. If, at a given date, this country owes a foreign nation considerably more than it has to receive, then bills on England will be plentiful in that country; and, further, they will be cheap, because, as debtors to England have less to remit than the aggregate of bills on England offered for sale, the supply will be in excess of the demand, and English bills, consequently, can be bought at a discount. Conversely, the supply of bills in London on the foreign country will be smaller than the sum English debtors owe therein, and in order to save the expense of exporting gold, such bills will be eagerly sought after, and, as the supply is smaller than the demand, buyers soon drive them to a premium, when the rate of exchange is said to be "unfavourable" to England. As the balance of our international indebtedness must be cancelled by gold, it follows that the fewer the bills offering the higher will be the prices paid for them; and when, just towards the end, it becomes evident that the supply is limited the bidding is often spirited; but the premium paid cannot exceed for any considerable length of time the expense incurred by exporting and insuring the precious metals between any two countries, as the debtor always has the choice of despatching gold to his foreign creditor, and, naturally, he chooses the cheaper expedient. The extreme fluctuations are called "gold points," and they mark the limit to premiums procurable on bills of exchange. The table given below will show us those points at which gold will probably either leave or reach this country: ============================================================ Exchange. | Mint Par. | Gold | Gold | of Exchange. | Exports. | Imports. -----------------+------------------+-----------+----------- London on Paris | Francs 25·22½ | 25·12½ | 25·32½ Berlin | Marks 20·43 | 20·34 | 20·52 New York | Dollars 4·87 | 4·84 | 4·90 ============================================================ When the rates are near those given in the second column, the Bank, if its reserve be low, begins to consider the advisability of raising its rate of discount, for it is evident that foreign bills are at a stiff premium, and that a demand for gold may be made upon it at any moment. Of course the difference between the "gold points" gives scope for speculation, and some cambists gamble in bills for the rise or the fall just as speculators do in securities. Then, again, the arbitrageurs largely influence prices by buying and selling securities which are dealt in on the Stock Exchanges of more than one country. Wars, revolutions, panics, and social upheavals also cause abnormal fluctuations in the rates.