Excerpt from An Elementary Manual of Radiotelegraphy and Radiotelephony: For Students and Operators The Author published in 1906, through Messrs. Longmans, Green and Co., a volume on the Principles of Electric Wave Telegraphy and Telephony, in which an attempt was made to provide a fairly complete treatment of the subject, not limited to mere descriptions of various so-called systems of wireless telegraphy, but explanatory of the scientific principles underlying Radiotelegraphy in general. It was, however, represented to him that a smaller manual on the subject, suitable for the use of students, practical operators, and the general reader, on the same lines, but somewhat more elementary, might meet with acceptance. The Author has, therefore, endeavoured to put together in the present volume the information most likely to be of use for this purpose. Where it has been deemed advisable to introduce some little mathematical reasoning to supplement the verbal descriptions, it is limited to the use of simple operations and expressions. For the proof of many of the formulæ given in this Manual, which require rather more extended mathematical discussion than can be given here, the reader must be referred to the Author's larger book above mentioned. It is assumed, however, that any user of this Manual has a general acquaintance with the elementary facts of electrical science. About the Publisher Forgotten Books publishes hundreds of thousands of rare and classic books. Find more at www.forgottenbooks.com This book is a reproduction of an important historical work. Forgotten Books uses state-of-the-art technology to digitally reconstruct the work, preserving the original format whilst repairing imperfections present in the aged copy. In rare cases, an imperfection in the original, such as a blemish or missing page, may be replicated in our edition. We do, however, repair the vast majority of imperfections successfully; any imperfections that remain are intentionally left to preserve the state of such historical works.