Wireless Telegraphy and Telephony

PREFACE Probably no marvel of modern science so grips the imagi- nation as the mystery of those quivering impulses which go forth invisibly to link a ship sailing over the seas with the shores of the distant land. The author has endeavored to furnish a comprehensive explanation, in simple language, of the theory and practice of this wonderful art, and to explain, as far as possible, the importance of the position occupied by wireless telegraphy to-day and the possibilities of to-morrow. The title of this book naturally limits the amount of dis- cussion that can be undertaken, and so, in the space at com- mand, there has not been any real attempt made to enter into any engineering or constructive details further than is necessary to make the text clear. Much that might properly be made a part of the preface has been embodied in the book, in order to avoid repetition, and to also bring certain matter to the attention of those readers who consider a preface to be merely an opportunity for the author of a book to express opinions very often quite foreign to the title, and so unconcernedly skip it with hardly more than a passing glance. The author wishes to extend his sincere thanks to Mr. H. W. Young, Editor of Popular Electricity ; to Mr. John Firth, to Colonel George P. Scriven, and to the Scientific American, for their kindness in supplying photographs for some of the illustrations, and to his friend, Mr. Safford Adams, who has kindly read the proofs and made many valuable suggestions. Alfred P. Morgan. May, 1915. iii