This Non-Physical Value may be: positive, or a value in excess of the physical property, or negative, or less than the physical value. In the case of a property having a negative intangible value, a deduction should be made from the physical value. It is further contended that, in making the physical appraisal, the purpose of the appraisal should not be permitted to modify the figures. The resultant figure should be the same, whether it is to be used as a basis for assessment, rate-making, or limitation of capitalization. It should be an engineering estimate of the amount of _bona fide_ capital still remaining in the property, or of the complete cost of reproduction under existing conditions, less depreciation. This figure is definite, within reasonable limits, and it cannot be conceded that it is permissible to vary it, submitting one result as a physical value for taxation, and another and different result as a present physical valuation for rate-making. There may be some question as to the propriety of using non-physical values for certain ultimate ends; in fact, the Supreme Court, in the Omaha and Knoxville water cases, clearly indicates that they must not be used for certain purposes; but, in any case, to furnish information, this element of value should be determined, and, as in the case of physical values, it should be an unchangeable figure[18] and should represent the difference between the worth of the actual physical property and the final business value of the property considered as an earning proposition. It is not necessary to go minutely into detail as to the various steps to be taken in making the appraisal of physical property. Each appraisal will offer some problems peculiar to itself, and no general set of rules can be laid down which will be applicable to all cases. It is deemed sufficient to call attention to general matters of major importance and to refer to some points which have not been mentioned in the preceding narrative, omitting argument in the case of such as have there been fully discussed. The distinction should be kept in mind that any element of value which belongs to the property by reason of its physical existence is classed as an element of physical value. The property is considered as an operating property in the sense that it is reproduced complete, ready to operate; and any expense, or any element of value needed to complete it, is an element of the physical value, but any value arising as a result of surplus earning power, any good-will value, going-concern value, or value due to established business, strategic location, favorable traffic arrangements, etc., should be considered as intangible values. The valuation of physical property is naturally divided into four parts: I. —The preliminary study, II. —The field inspection, III. —The computation, IV. —The preparation of the final figure. I.—The Preliminary Study.