To buy in one market, in order to sell with profit in another, when there are many competitors in both; to watch over, not only the occasional variations in the demand, but the much greater and more frequent variations in the competition, or in the supply which that demand is likely to get from other people; and to suit with dexterity and judgment both the quantity and quality of each assortment of goods to all these circumstances, is a species of warfare, of which the operations are continually changing, and which can scarce ever be conducted successfully, without such an unremitting exertion of vigilance and attention as cannot long be expected from the directors of a joint stock company.