One of those subdivisions is Capital, which, in its technical meaning, is distinctively a part of Wealth produced by Labor from and upon Land. It is, however, often used loosely to include Land, the technical term for Natural Resources. Even slaves, and by Economic as well as by private business classification, have been placed in the subcategory called Capital, a form of Wealth; and this notwithstanding that as units of the human factor, slaves belong in the Labor category of Economics. Although such loose distinctions may be of use in private business accountings, they are intolerable in the science of Economics, which, like every other science, demands precision in the differentiation of terms. The application of Man’s powers of body and mind to Natural Resources for the production of Artificial Objects--of Labor to Land for the production of Wealth--is the Productive Process in Economics. It involves such subcategories as business enterprise, professional service, invention, hired-man work--in a word, every grade of useful activity. These subcategories are developed by industrial specialization, or, in technical Economic terms, Division of Labor, which necessitates another subcategory. This is Trade. Without Trade, products of Labor specialization would remain forever useless; but through Trade the most minute and incomplete of those products is brought to its useful place in the aggregate of Wealth--ploughshares to ploughframes, for instance, or ore to the steel of the factory, or wallpaper to the interior of the house. The Productive Process though intricate through specialization and Trade, is readily observable by generalization into the three major categories, Labor and Land and Wealth. In observing that Process care must be taken to distinguish delivery from Distribution. Delivery is part of the Productive Process. No Wealth is completely produced until it has been delivered to ultimate consumers. But Distribution has to do with Wealth apportionment. In apportionment, or Distribution, there are two major categories, Wages and Rent, corresponding respectively to the two Production categories, Labor and Land. A minor Distributive category, corresponding to the minor category in Production called Capital, is distinguished as Interest. This term identifies the earnings of Capital. Inasmuch, however, as Capital is part of Labor-produced Wealth, Interest must be a subdivision of Labor-earned Wages.