GEORGE T. HAMMOND, M. AM. SOC. C. E. (by letter).—The engineer called on to fix the valuation of public service corporation property has so little engineering literature on this special subject to guide him that he must feel grateful to the author of this excellent paper for adding so much of a kind that is very desirable. Estimating the cost of an engineering structure in advance of its construction is one of the most ordinary professional duties, but how difficult it actually is, and how much engineers differ with one another in their estimates on the same structure! Perhaps there is no professional duty which calls for so much study and so much experience, or which tests so closely the ability and capacity of the engineer. How seldom professional estimators agree with each other; or designing engineers with contracting engineers; as witness the bids received at the public lettings of contracts when compared with the engineers' estimates of cost; and, if this is true, which no one will attempt to deny, how much more so is it probable that estimators will disagree when they attempt to place a value on works already completed, and in service, perhaps, for many years, in which various changes in value have occurred, and in which questions of fact are mixed with legal questions involving legal rights, as well as financial questions. The tendency in all such valuations appears to be a mixing up of things in general—like the witches' stew. Everything goes into the pot and is boiled together until all becomes soup, at least until the official commission, like the witches, considers it done and ready to be served up in the form of a report. It is then observed that the substance served out is of a complex nature; that the valuation of engineering structures has become mixed with other and uncertain values; that the whole value, as stated, is, after all, little better than the commission's opinion of the value; and that another commission would reach a different conclusion. The author states that the valuation of corporation property: "Should be the honest judgment of the men composing the commission, as to the actual cost of reproduction, present physical value, or 'fair value,' and should be ascertained by a systematic and scientific method which takes into account all the facts concerning the property, its physical value, its strategic location, its operating revenues and expenses, and its franchises, rights, competition, opposition, and all other tangible or intangible elements, which would affect values. The method of valuation should be such as to minimize or entirely eliminate all differences due to errors of personal judgment."