The telegraph manual: a complete history and description of the semaphoric, electric and magnetic telegraphs of Europe, Asia, Africa, and America, ancient and modern.

PREFACE.
IN the preparation of this volume, the author has not
advanced theories, other than those which are founded upon
demonstrated philosophy. It is to be understood, however,
that many of the views expressed concerning questions in the
sciences may, from time to time, be modified by new developments. In every instance, the opinions given are based upon
the known sciences as manifested through the medium of the
arts, and more particularly the electric telegraph.
I have reviewed the early semaphore telegraphs, and explained their respective modes of operation. These visual
systems have, however, ceased to be employed by civilized
nations, except for the marine service.
As preliminary to the consideration of the electric telegraph,
I have introduced a few chapters explanatory of the sciences
immediately blended in that art; such, for example, as static
and voltaic electricities, magnetism, and electro-magnetism.
These questions of philosophy the telegrapher should most
carefully study. The data given are from the most reliable
authorities.
In the collection of materials for this work I have spared
neither labor nor expense. For nearly fifteen years I have
made the subject-matter of this volume my most careful study.
For the greater part of that time, practical telegraphing has
been my sole vocation. I have instituted thousands of experiments, and have travelled over most of the civilized world
" in search of light" upon this, the most important of all arts.
The information herein imparted has cost me years of toil and