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

8 CONTENTS.
CHAPTE VI.
VOLTAIC ELECTRICITY.
Electrical Phenomena Discovered by Galvani-Origin of the Voltaic Pile -Science of
the Voltaic.Battery-Onm's Mathematical Formulae-Chemical and Electrical Action
of the Battery-The Daniell, the Smee, the Bunson, the Grove, and the Chester Voltaic Batteries-Comparative Intensity and Quantity of the Grove, Daniell, and Smee
Batteries.......................................................... 7
CHAPTER VII.
MAGNETISM.
Native Magnetism of the Load-Stone-Attractive and Repulsive Forces of Permanent
Magnets-Componentparts of the Magnet-Induced Magnetism............... 105
CHAPTER VIII.
ELECTRO-MAGNETISM.
Discovery of Electio-Magnetism by (Ersted-Discoveries of Schweigger, Arago, and
Ampere-Discoveries of Sturgeon and Henry-Recapitulation of the Discoveries on
Electro-Magnetism-English Telegraph Electrometers-Magnetometers-The De La
Rive Ring and other Experiments................................ 114
CHAPTER IX.
EARLY ELECTRIC TELEGRAPHS.
Suggestions of Science-The Telegraph of Lomond-Reizen's and Dr. Salva's Electric
Spark Telegraph-Baron Schilling's, Gauss and Weber's, and Alexander's Telegraphs..................................................... 132
CHAPTER X.
SOEMMERING S ELECTRO-CHEMICAL TELEGRAPH.
Soemmering's Electric Telegraph of 1809-The Apparatus and Manipulation Described
-Signal Keys for opening and closing the Circuits........................... 142
CHAPTER XI.
RONALD S ELECTRIC TELEGRAPH.
Invention of Ronald's Electric Telegraph-Experiments and Description of the Apparatus-Description of an Electrograph..................................... 147
CHAPTER XII.
STEINHEIL'S ELECTRIC TELEGRAPH.
Experiments and Discovery of the Earth Circuit-The Electric Telegraph as Invented
-The Electric Conducting Wires-Conductibility of the Earth Circuit-Apparatus
for Generating the Electric Current-The Indicating Apparatus-Construction of the
Apparatus-Application of the Apparatus to Telegraphing-The Alphabet and Numerals-The Discovery and Invention of Steinheil......................... 157