That a power to lay taxes or duties on exported products belongs to every government possessing a general authority to select the objects from which its revenues are to be derived, is a proposition which admits of little doubt. It is not to be doubted, either, that it is a power which may be attended with great benefit, not only for purposes of revenue, but for the encouragement of manufactures; and it is clear that it may often be used as a means of controlling the commercial policy of other countries, when applied to articles which they cannot produce, but which they must consume. A government that is destitute of this power is not armed with the most complete and effectual means for counteracting the regulations of foreign countries that bear heavily upon the industrial pursuits of its people, although it may have other and sufficient sources of revenue; and therefore, until an unrestricted commercial intercourse and a free exchange of commodities become the general policy of the world, to deny to any government a power over the exported products of its own country, is to place it at some disadvantage with all commercial nations that possess the power to enhance the price of commodities which they themselves produce. But, on the other hand, the practice of taxing the products of a country, as they pass out of its limits to enter into the consumption of other nations, can be beneficially exercised only by a government that can select and arrange the objects of such taxation so as to do nearly equal justice to all its producing interests. If, for example, the article of wine were produced only by a single province of France, and all the other provinces produced no commodities sought for by other nations, an export duty upon wine would fall wholly upon the single province where it was produced, and would place its production at an unequal competition with the wines of other countries. But France produces a variety of wines, the growth of many different provinces; and therefore, in the adjustment of an export duty upon wines, the government of that country, after a due regard to the demand for each kind or class of this commodity, has chiefly to consider the effect of such a tax in the competition with the same commodity produced by other nations.