Whenever a people produce more of any commodity than is required for their own consumption, the surplus must find a foreign market, or the production will not be extended beyond the home demand. Any thing, therefore, which has a tendency to prevent the sale of domestic products in a foreign market must discourage home industry. Such being the case, what must be, in general, the effect of duties laid upon exports? Evidently to reduce the amount exported, and benefit the foreign producer of the articles thus taxed. Take the article wheat as an illustration. It can be produced in almost every country, and is an article of export from many. Such are the facilities afforded by commerce, that the wheat of one country must enter into competition with the wheat of every other country; and it may therefore be taken as a fair exponent of commodities in general.

If the price of wheat in New York is one dollar and fifty cents under a currency at par with specie, it is because it can be shipped to Liverpool or some other foreign port, and, after paying freight and charges, make a remittance equal to one dollar and fifty cents in specie. Under these circumstances, we will suppose an export duty of twenty-five cents per bushel is laid on wheat.

Would the New-York dealer now pay one dollar and fifty cents per bushel for the wheat? Certainly not, since he could not export it without paying, in addition, a duty of twenty-five cents per bushel; and, unless the article should rise abroad, he would lose to the amount of the duty paid. Of course, he now offers but one dollar and twenty-five cents instead of one dollar and fifty cents, and the difference is the loss of the producers, who, in consequence of the export duty, are at a disadvantage of twenty-five cents per bushel, as compared with the wheat-growers of every other country. They have nothing left but to accept a reduction of twenty-five cents per bushel, or limit their production in the future to the amount required for home consumption. When they have done this, the price of wheat will correspond with the prices of all the other agricultural products of the country, whatever that price may be: for all such products will be affected by an export duty laid on the great staple of agriculture; every kind of grain and meat, as truly as the wheat on which the duty was laid, though not, perhaps, in the same degree. But, since the foreign market has been to a large extent dependent for its full supply upon American wheat, will not the price advance to such a point as to bring up the price of the American article? If the American wheat must be had, such a price must be offered as will bring it. But, as soon as wheat begins to rise abroad from this cause, a larger supply will be attracted from other wheat-growing countries, in which production will be stimulated to the extent it is depressed in the United States. The price having risen, a limited amount will go from our ports; but wheat will not rise permanently to such a point abroad as to make it twenty-five cents higher in the United States. The American producer must, in any event, take a part of the loss, and the foreign consumer the balance; while foreign producers, having an unnaturally high price, will extend their cultivation as far as possible.

The unquestionable effect of export duties is to lessen production at home, and give encouragement to foreign labor. This is a general principle, applicable to every commodity of home growth or production, except such as one nation may have a virtual monopoly of; that is, may be able to produce in so much greater perfection, or at so much lower rate of cost, or both, that no other nation can compete with it. In that case, the exporting nation might impose a duty, which, while it should create a revenue, would not lessen production materially, if at all.