ABSTRACT
A group of complementary goods is valued as a whole; if the hook is missing the eye is worthless, and the hook will be worth the same as both hook and eye. Productive agents will not render their services gratuitously; they resist our efforts to compel them to supply our needs. In order to grasp the significance of this principle it is necessary to hold two things in mind: a limited agent and static conditions. Resistance limits the supply of products coming from any one agent. Men do not labor to harness a valueless use, and this they would do should they cultivate valueless land. The heaviest expenditures are justified only upon the most valuable land. One attempts to withdraw his capital from the less paying occupation in order to invest it in the more remunerative occupation. A certain factor is found to hold a monopoly position, at times, and all the other factors must be adjusted to it.
