Professor Adams has himself admitted that there is no possibility of utilizing any valuation for the purpose of fixing specific rates, as such a task is far beyond the capacity of any conceivable system of cost accounting. Supplementing this admission, Mr. Riggs' opposition to the plan proposed by the former and its gross injustice, so apparent to every one but its author, destroys the last element of plausibility in the suggestion that any sort of valuation could be of utility in that connection. The writer is not overlooking the fact that the Courts, when under the necessity of repelling efforts to confiscate railway properties under the guise of rate regulation, and in view of the form in which this necessity has commonly presented itself, have accepted "fair value" as an element of importance in their inquiries; but if the railways are entitled to charge rates based on the value of the services they perform, it is clear that the question whether a rate or a schedule of rates is reasonably adjusted to the value of the service or services is very different from the question whether a fair return upon fair value has been allowed. Assuming, however, the need of an appraisement in every litigated case involving railway schedules, it is evident that each case would have to have its own appraisement, for value is ever changing and unstable. Mr. Riggs himself says: "It is true that the 'value' of a property is an unstable figure, subject to fluctuations due to natural or artificial causes, and that a material change in value may occur suddenly...." Professor Adams proposed to keep his replacement cost up to date by annual accretions equal to annual expenditures for extensions and betterments; but this plan is illogical and inconsistent, for it proposes to ignore that very essential difference between original cost (less a proportionate allowance for wear and tear) and present worth, which is the very basis of the argument in favor of any valuation at all. Equally obvious objections, growing out of the instability of the ascertained value of any particular date, apply to any plan which does not provide for a re-appraisement every time the aggregate is to be used.