When the produce of any particular branch of industry exceeds what the demand of the country requires, the surplus must be sent abroad, and exchanged for something for which there is a demand at home. Without such exportation, a part of the productive labour of the country must cease, and the value of its annual produce diminish. The land and labour of Great Britain produce generally more corn, woollens, and hard ware, than the demand of the home-market requires. The surplus part of them, therefore, must be sent abroad, and exchanged for something for which there is a demand at home. It is only by means of such exportation, that this surplus can acquire a value sufficient to compensate the labour and expense of producing it. The neighbourhood of the sea coast, and the banks of all navigable rivers are advantageous situations for industry, only because they facilitate the exportation and exchange of such surplus produce for something else which is more in demand there.
When the foreign goods which are thus purchased with the surplus produce of domestic industry exceed the demand of the home-market, the surplus part of them must be sent abroad again, and exchanged for something more in demand at home. About ninety-six thousand hogsheads of tobacco are annually purchased in Virginia and Maryland, with a part of the surplus produce of British industry. But the demand of Great Britain does not require, perhaps, more than fourteen thousand. If the remaining eighty-two thousand, therefore, could not be sent abroad and exchanged for something more in demand at home, the importation of them must cease immediately, and with it the productive labour of all those inhabitants of Great Britain, who are at present employed in preparing the goods with which these eighty-two thousand hogsheads are annually purchased. Those goods, which are part of the produce of the land and labour of Great Britain, having no market at home, and being deprived of that which they had abroad, must cease to be produced. The most roundabout foreign trade of consumption, therefore, may, upon some occasions, be as necessary for supporting the productive labour of the country, and the value of its annual produce, as the most direct.