THE PREFATORY. HE OBJECT of this book is to give in a convenient form the properties and dimensions of bare and insulated wires and cables used in electrical construction. No attempt has been made to describe the uses of wire in any of the applications of electricity., To go into this would require that the whole field of electrical engineering be covered. It is believed that some of the matter is new. All of the tables have been very carefully computed, and are believed to be correct. In nearly all cases the formulæ and constants used in computing tables are given, so that the user can determine at once the basis from which the table was calculated. A considerable amount of work has been done in testing samples to determine the proper constants. In many cases this has taken more time than the actual preparation of the tables. It is hoped that the work will be acceptable to the users of electrical wires, and that some of the labor involved in the preparation of these tables will be saved to those using the book. TRENTON, N. J., May, 1897. JOHN A. ROEBLING'S SONS Co. iii |