boots, therefore, only cost him half as much as before. In the same way the San Franciscans could obtain plantain preserves, cocoa-nuts, and palm oil from the island at the sacrifice of half the labour, compared with that which the things would have cost to produce in their own country.
In this way it was proved to the islanders that foreign trade, to be permanent and beneficial, must be in the nature of an exchange of commodities for commodities. If one country sends commodities and is paid entirely in money, it parts with its real wealth without receiving any substantial advantage; and if this kind of trade is carried on for any length of time, prices go up in the exporting country, and go down in the importing country, till at last prices in each country are made equal, and in this case the motive for trade carried on in this way ceases to exist. For when the islanders could obtain no more money for their goods in San Francisco than at home, they naturally preferred to sell them at home rather than to run the risk and to bear the delay of
