"... it fails, in the form in which it was used in 1900 and 1902, to bring out those negative or subtractive elements which may be determined from the income accounts, in the case of properties which do not earn a fair return on the investment." And again: "... where the earnings have been fairly uniform and stationary for a period of years, and the property does not earn a sufficient sum to care for depreciation and annuity, it is clear that the value as an earning investment is less than the determined physical value, and that the physical valuation should be reduced by some amount to arrive at the 'fair value.'" In his argument favoring the use of a valuation in rate-making, Mr. Riggs affords no support to Professor Adams' contention that, for that purpose, only replacement cost should be considered, and that, after fixing the rates on the basis of the least favorably located and least efficient line, so as to afford it a bare return on its replacement cost, the surplus earnings at the same rates of its more favorably located or better operated competitors should be confiscated under the guise of a special tax. This extraordinary proposal, the character of which is so illuminating as to the attitude toward railway property and investments of the most prominent and persistent advocate of so-called "physical valuation," is best stated in Professor Adams' own words, which are as follows: "I cannot evade the conclusion that equity, as between various classes of roads, can never be attained until all the excess of revenue over the Constitutional limit be made a contribution to the public treasury, and that this contribution be made as a substitute for all taxes of all kinds and all sorts."[38] On the contrary, Mr. Riggs distinctly upholds the right to earnings in excess of the bare return, at the minimum rate of interest, upon the cost of replacement, saying, _inter alia_: "It is contended that the determination of rates that will be just and fair to all competing companies involves other consideration than the valuation of either physical or intangible properties, and that when all these rate-making problems are properly solved, there will remain large intangible values on the well-designed plants."