In the days when extensive alterations in the currency of trading countries were common, commerce was much indebted to the intervention of such men as Visscher. The bill-brokers held the power of equalizing the exchange, or of preventing its variations from exceeding a certain limit. The variations of the real exchange can, it is true, never exceed the limit fixed by the cost of transmitting metals; for, as soon as the premium which a merchant has to pay on the bill he wishes to purchase is higher than the expense of sending gold and silver, he, and others circumstanced like himself, will pay debts in money, the competition for bills will be lessened, and their price will fall: but the tendency which the exchange has to correct itself is much assisted by the operations of the bill-brokers, who, as they deal in the bills of many countries, can transport this kind of currency from places where it is superabundant to places where it is scarce. Like all other traders, they seek to buy where their article is cheapest, and to sell where it is dearest; and this, of course, lessens the cheapness and the dearness in different places. At the present time, the bills on England were cheap at Amsterdam, and dear in Leghorn; and Visscher, and other bill-brokers, by buying up bills on England, and transmitting them to Leghorn, assisted in equalizing the demands of Holland and England, and also of Leghorn and England, on each other, and thus aided in restoring the exchange to par. But when the currency of any country is altered, no operations of the bill-brokers, or of any one else, can prevent the exchange from _appearing_ to sustain a great variation, though those who understand the circumstances, and are not apt to be alarmed by the mere sound of words, know that, in such a case, if the exchange be really at par, it cannot be nominally so, and do not therefore trouble themselves about the apparent difference. This nominal variation does not affect trade; because the decrease in the price of goods to be exported answers to the discount which the exporting merchant sustains on his foreign bill: that is, if an English merchant draws a bill on Amsterdam for 1000 guilders in return for 90_l._ worth of goods, the discount at which the Englishman sells his bill exactly answers the saving he has made from the price of the goods exported being lowered through the depreciation of the English currency: while the premium which the bill would bear in Paris answers to the apparent surplus of the 100 guilders. The holders of bills drawn before the alterations in the currency took place are affected by such changes; and such liabilities to profit and loss are among the evils attendant upon fluctuations in currency; but the amount of exportation and importation, and therefore the real exchange, are in no wise affected by alterations in the representative of their value.