THE author's object in foisting still another bridge book upon his long-
suffering brother engineers is twofold, viz.:

A desire to leave behind him for the benefit of the next generation of bridge specialists, in shape readily available for use, a solution of all the majoreconomic problems in bridgework and an extensive treatment of most of the minor ones. He has endeavored to cover every possible economic question of importance; and, if any such be omitted, it is because he did not recognize their existence. To what extent he has succeeded in this endeavor can be determined only by the reception which the book meets from the engineering profession.

To show to specialists in all branches of the engineering profession the type of book on economics which, in his opinion, each specialty needs and how broad and thorough, if possible, should be the treatment of the subject.

The author feels that he is the logical person to write a book upon the economics of bridgework, because he has been investigating the matter for thirty-seven years, and has dealt at length, upon more than twenty different occasions, in books, pamphlets, and memoirs, with various economic topics on the subject of bridge designing, as can be seen by referring to the list of the said writings given in the Appendix.

An explanation but not an apology is needed for the fact that certain portions of "Bridge Engineering" have been copied in a few of the chapters. As that work from start to finish is impregnated with the fundamental idea of economy, and as this book is intended to cover the entire field of bridge economics, it was necessary to include herein the gist of all that appears on the matter in that work, as well as the substance of all the author's economic writings that are subsequent to its publication. Wherever anything previously written on the subject could advantageously be modified or enlarged, this has been done; but where it could not be improved upon or augmented, the only thing to do was to copy it verbatim. Hence, should any reader see any portion of "Economics of Bridgework," which appears familiar to him, if he has read this preface he will understand the reason therefor and will, the author trusts, excuse the occurrence.

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