The most conspicuous method yet suggested for realizing such a Value level takes the specific form of a proposal to determine Money standards by frequent comparisons with the Price level of simple types of Wealth. Resting nominally upon the Value in Trade of such staples, this method rests fundamentally upon the Economic fact that Labor, as the continuous producer of all Wealth, is the real source and regulator at all times of all Values in the channels of Trade, and that Money is the measuring rod and its terms the language. To go farther into this Economic field would necessitate a surface survey of Economic intricacies, and these pages aim only at clarifying fundamentals. Having returned from the Basic Facts, upon which all Economic details rest, to the Money surface with which it began, our common-sense primer for advanced students is at the end of its task. SEVENTH LESSON REVIEW The science of Economics, having now been traced from its surface to its three Basic Facts and back to the surface, let us, for the purpose of bringing the whole subject compactly within its narrowest limits, retrace our steps briskly but thoughtfully by way of review. Economic accomplishments are measured by Money standards and expressed in Money terms. Resting on the surface, those standards and terms spread over the whole Economic area. Beneath that surface we first find Trade, for which Money is the medium or the means of expressing relative values and adjusting balances. Trade consists essentially in interchanges of commodities, inclusive of natural resources and of human service. It is not an arbitrary custom or set of customs, but a phenomenon of natural law through which artificial objects are produced to completion and final delivery. But Trade, though lying beneath the Money surface of Economics, is not a basic fact of that science. Only by piercing through the Trade surface as well as the Money surface, can the bottom level of the Basic Facts of Economics be reached. Those facts consist of distinct categories which comprehend in generalized forms the myriads of miscellaneous facts with which the Science of Economics is concerned. Of those categories or Basic Facts there are in number neither more nor less than three--Man, Natural Resources, Artificial Objects. All Artificial Objects are produced by Man from and upon Natural Resources. The technical term for the activities of Man in that connection is _Labor_; for Natural Resources, _Land_; and for Artificial Objects, _Wealth_. In technical Economic terms, therefore, all Wealth is produced from and upon Land by Labor. Many colloquial and business subdivisions of those three categories may be useful provided they be not mixed in their meanings.