The author's statement that the organization, legal, engineering, administration, and general expense accounts, "should not be considered as affected by depreciation, as long as the property is a going concern," is not quite clear. Obviously, this is true with regard to all the early organization expenses, as these expenses are incurred once for all, and constitute a continuing asset similar to other elements of plant cost. If, however, the author refers therein also to the engineering and contingent item added to many of the reproduction cost items making up the physical property, exception must be made; for when an old structure, the life of which is gone, is replaced with a new structure, new engineering costs are incurred, and the engineering element of cost incident to the installation of the original structure no longer inheres in the plant. It, too, has passed away with the life of the structure, and, therefore, its cost should be liquidated, or provided for in the depreciation account, as well as the cost of the structure to which it was incident. In the same way the "interest-during-construction" item is not a continuing asset, but should be liquidated with the complete depreciation of the portion of the structure to which it relates. The replacement of the structure will involve new "interest-during-construction" charges, commensurate with the time required for construction. The value of the initial "interest-during-construction" costs will have disappeared with the original structure and, therefore, should be taken care of by the depreciation account. The method of making allowances for interest during construction, suggested by the author,[44] accords closely with that used by Mr. Alvord and the writer in a recent valuation of a large water-works property, in which the "interest-during-construction" charges were limited, and the contributions to depreciation account were begun, at the date on which any workable unit of the property was assumed to be available for service and to begin to earn a return on its investment cost, even though the structure, as a whole, was not assumed to be completed for a considerable period of years thereafter. Thus, for instance, it might be assumed that as soon as the supplying works in a water-works project were in operation, the investment in them and in the distribution pipe system laid up to that time, would cease to be credited further with "interest-during-construction" allowances, and would be compelled to earn interest through the water rates or income from water supplied to consumers—the fact that the interest charge could not be wholly met, immediately at this time, being taken care of in the resulting increment in going value. Such a theory, of course, does involve a determination of the probable order and rapidity of construction of the component parts of the property, and this is usually made, in water-works valuation, in the estimate of the reproduction cost of the property.