[1] For extended discussions of the relations of utility and value the reader is referred to the works of Jevons, Menger, Von Wieser, Von Boehm-Bawerk, and Walras. A study of "effective" utility and its relations to value, by the writer of the present treatise, is contained in the _New Englander_ for July, 1881. _The Utility of Producers' Goods._--Consumers' goods have a direct utility, which is a power immediately to serve a consumer. Instruments of production, on the other hand, have indirect utility, since all that they are good for is to help produce things that render the immediate service. They have _productivity_, and this has to be measured in determining their value. What we need to know about hoes and shovels, hammers and anvils, spindles and looms, etc., is how much power they have to create the goods that we want for consumption. Here again the measurement has to be made in the specific way. The capital goods have to be taken unit by unit if their value for productive purposes is to be rightly gauged. A part of a supply of potatoes is traceable to the hoes that dig them; but in valuing the hoes we do not try to find out how much worse off we should be if we had no hoes at all. We endeavor simply to ascertain how badly the loss of one hoe would affect us or how much good the restoration of it would do us. This truth, like the foregoing ones, has a universal application in economics; for primitive men as well as civilized ones must estimate the specific productivity of the tools that they use, and make hoes, shovels, or axes according as the procuring of a single tool of one kind becomes more important than procuring one of another kind. Indeed, the measuring of the utility has to be done, as we shall soon see, in a way that is even more specific than this; for the man has to determine not only how many hoes he will make, but how good he shall make them. The quality of each tool has to be determined in a manner that we must hereafter examine with care. The earning power of capital is, as we shall later see, governed by a specific power of productivity which resides in capital goods.