that, so long as the quantity of a natural agent is practically unlimited, it can not, unless susceptible of artificial monopoly, bear any value in the market, since no one will give anything for what can be obtained gratis. But as soon as a limitation becomes practically operative—as soon as there is not so much of the thing to be had as would be appropriated and used if it could be obtained for asking—the ownership or use of the natural agent acquires an exchangeable value.
When more water-power is wanted in a particular district than there are falls of water to supply it, persons will give an equivalent for the use of a fall of water. When there is more land wanted for cultivation than a place possesses, or than it possesses of a certain quality and certain advantages of situation, land of that quality and situation may be sold for a price, or let for an annual rent.
§ 2. The Second Requisite of Production, Labor.
It is now our purpose to describe the second requisite of production, labor, and point out that it can be either direct or indirect. This division and subdivision can be seen from the classification given below. Under the head of indirect labor are to be arranged all the many employments subsidiary to the production of any one article, and which, as they furnish but a small part of labor for the one article (e.g., bread), are subsidiary to the production of a vast number of other articles; and hence we see the interdependence of one employment on another, which comes out so conspicuously at the time of a commercial depression.
“We think it little to sit down to a table covered with articles from all quarters of the globe and from the remotest isles of the sea—with tea from China, coffee from