The definition given by Professor Adams is: "The estimate placed upon the worth of a property, regarded as a business proposition." Both these definitions are in a measure involved, and the writer considers that the term, "Commercial Value," is too narrow and restricted to be properly used. As a definition of that estimate of worth which an engineering commission should report as the result of a complete appraisal, the writer submits the following: The value of a property is its estimated worth at a given time, measured in money, taking into account all the elements which add to its usefulness or desirability as a business or profit-earning proposition. There are two classes of elements entering into the final value: _(1) The "Physical Property" Element of Value._—This consists of those things which are visible and tangible, capable of being inventoried, their cost of reproduction determined, their depreciation measured, and without which the property would be unable to produce the commodity on the sale of which income depends. This physical property is considered as an operating entity, and not as collateral of inert and partly worn-out equipment, and, being so considered, carries, as part of the physical value, those costs and charges which are an inseparable part of the cost of construction but do not appear in the inventory of the completed property. _(2) The "Non-Physical" or "Intangible" Elements of Value._—These are those things which, added to or taken from the worth of the physical property, make up the value, and include whatever accrues to the property by reason of its operation, or by reason of grants, contract rights, competition, or location, which at the time of appraisal affect favorably or unfavorably the worth of the property. The worth of the physical property is primarily that on which the value of the whole property rests. While it is clear that the worth of the physical property, being the cost of reproduction less depreciation, is not necessarily the value of the property, it is equally clear that the physical worth must bear some very definite relation to value, and the writer is strongly of the conviction that this relation is such that "value" cannot be ascertained without a determination of physical worth. The physical property element represents the investment on which a fair return is to be earned, and in most cases an appraisal is necessary for the determination of the amount of money actually invested. As illustration of the fact that "physical value" and "value" are not the same, the case of two railroads actually existing and in operation between two cities in Michigan may be cited.