‹Limits of Exchange.›—The general character of Exchange is ‹to diminish the proportion which the Effort bears to the satisfaction›. Between our wants and our satisfactions ‹obstacles› are interposed, [p112] which we succeed in diminishing by the union of forces or the division of occupations, that is to say, by ‹Exchange›. But Exchange itself encounters obstacles and demands efforts. The proof of this is the immense amount of human labour which it sets in motion. The precious metals, roads, canals, railways, wheeled carriages, ships—all these things absorb a considerable portion of human activity. Observe, besides, how many men are exclusively occupied in facilitating exchanges—how many bankers, merchants, shopkeepers, brokers, carriers, sailors! This vast and costly apparatus shows us, better than any reasoning, how much efficacy there is in the power of Exchange, for why otherwise should society be encumbered with it? Since it is the nature of Exchange to ‹save› efforts and to ‹exact› them, it is easy to understand what are its natural limits. In virtue of that motive which urges man to choose always the least of two evils, Exchange will go on extending itself indefinitely as long as the effort it exacts is less than the effort which it saves. And its extension will stop naturally when, upon the whole, the aggregate of satisfactions obtained by the division of labour becomes less, by reason of the increasing difficulties attending Exchange, than if we procured them by direct production. Suppose the case of a small tribe. If they desire to procure themselves satisfactions they must make an effort. They may address themselves to another tribe, and say to them, “Make this effort for us, and we shall make another for you.” The stipulation may suit all parties, if, for example, the second tribe is in a situation to obtain greater assistance than the other from natural and gratuitous forces. In that case it may be able to realize the result with an effort equal to eight, while the first could only accomplish it by an effort equal to twelve. There is thus an economy equal to four for the first. But then come the cost of transport, the remuneration of intermediate agents, in a word, the effort exacted by the machinery of Exchange. This cost must, then, clearly be added to the figure eight. Exchange will continue to take place as long as the Exchange ‹itself› does not cost four. The moment it reaches that figure it will stop. It is quite unnecessary to make laws on this subject; for either the law intervenes before this level is attained, and then it is injurious—it prevents an economy of efforts—or it comes after it, and then it is useless, like an ordinance forbidding people to light their lamps at noonday.