The case in which this statement requires qualification is that in which the material in its rawest state still has value, as is the case with ore and mineral oil contained in the earth but not a true part of land in the economic sense, since they are exhausted in the using. The price of a product into which these elements enter includes something that represents the value which they have _in situ_ and before any labor has been expended on them. It is true even in these cases that the value of the product is measured in terms of wages and interest, provided that the exhaustible elements such as ore, oil, etc., are capable of being replenished, or provided that an effective substitute for them is in process of production by means of labor and capital. The natural raw material is then worth what the artificial substitute costs in terms of capital and labor, and the finished product which contains some of the natural material sells for the amount which the finished product costs, which is made altogether by labor and capital applied to valueless elements in nature. _How Costs are Determined._--The early studies of "natural" values, or values which conform to costs of production, were unconscious and imperfect attempts to attain the laws of value in a static state. In such a state costs resolve themselves into wages and interest, and the conception of such a static state is therefore not complete unless we know how wages and interest themselves are determined. What we have already said implies that they fluctuate about certain standards, just as do the prices of goods, and that they would remain at these standards if society were reduced to a static condition.