Mr. Cairnes(213) fitly says: “The supply of a commodity always tends to adapt itself to the demand at the normal price. I may here say briefly that by the normal price of a commodity I mean that price which suffices, and no more than suffices, to yield to the producers what is considered to be the average and usual remuneration on such sacrifices as they undergo.” When at any time it fails of so conforming, it is either from miscalculation, or from a change in some of the elements of the problem; either in the natural value, that is, in the cost of production, or in the demand, from an alteration in public taste, or in the number or wealth of the consumers. If a value different from the natural value be necessary to make the demand equal to the supply, the market value will deviate from the natural value; but only for a time, for the permanent tendency of supply is to conform itself to the demand which is found by experience to exist for the commodity when selling at its natural value. If the supply is either more or less than this, it is so accidentally, and affords either more or less than the ordinary rate of profit, which, under free and active competition, can not long continue to be the case. To recapitulate: demand and supply govern the value of all things which can not be indefinitely increased; except that even for them, when produced by industry, there is a minimum value, determined by the cost of production. But in all things which admit of indefinite multiplication, demand and supply only determine the perturbations of value during a period which can not exceed the length of time necessary for altering the supply. While thus ruling the oscillations of value, they themselves obey a superior force, which makes value gravitate toward Cost of Production, and which would settle it and keep it there, if fresh disturbing influences were not continually arising to make it again deviate. Chapter II. Ultimate Analysis Of Cost Of Production. § 1. Of Labor, the principal Element in Cost of Production.