In actual life the problem is far more complex, and yet, through its settlement runs just the same principle. There is constant bidding for materials, and through their price the claims of rival products are adjusted. A point is reached where it does not pay to use any more of an agent in a certain industry; the production of another unit results in a loss. There is a most complex relation among many different industries using the same factors, the value of a unit of product (at _a_) being reflected up to the source, and through successive links to the most distant product (_z_). The effect of this is to reduce the sale (of _z_) and correspondingly the use made of the agent in question. A higher price of leather, due to the increased use of shoes, raises the value of hides and cattle (this increasing the extent of cattle raising) and raises thus the cost of carriage-trimmings, pocket-books, foot-balls, leather belts, and every other leather product. As the price rises, substitutes for leather, and imitations of it, are used for such of the products as cannot bear the increased cost of leather. [Illustration: _3. Complex Relations Through Intermediate Products_] [Sidenote: The enterpriser the medium of price movements] [Sidenote: Costs are an expression of consumers' estimates] 4. _The enterpriser does not fix the value of products or of agents, but is the medium through which consumers express their estimates._ The enterpriser who anticipates aright and satisfies the public taste is the good medium. He readily transmits and accurately focuses the rays of public judgment. One that misjudges is a poor medium. The enterpriser is himself the servant of costs. Laborers sometimes assume that the employer can dictate wages, prices, and markets, can rule things with a lordly hand. With rare exceptions the ultimate control in these matters by business men is very slight. In the main the enterpriser masters the situation only by bowing to it, just as the scientist and the engineer gain mastery over nature because they know when to bend and how to obey. The consumer, by deciding to buy this or that product, sets in motion waves of value. The consumers of products are the true purchasers of labor, materials, and uses of agents. The enterpriser must conform closely to cost, to the price prevailing for the moment, or his competitors in this day of narrow margins will seize the opportunity. The enterpriser is merely the distributor or equalizer of cost among all the different products for which different agents can be used. If he acts efficiently, profits arise. CHAPTER 31 THE LAW OF PROFITS § I. MEANING OF TERMS [Sidenote: Broadest use of the term profit]