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

STEINHIEIL'S ELECTRIC TELEGRAPH
CHAPTER XII.
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 Voltaic Current-The Indicating
Apparatus-Construction of the Apparatus-Application of the Apparatus
to Telegraphing-The Alphabet and Numerals-The Discovery and Invention of Steinheil.
EXPERIMENTS AND DISCOVERY OF THE EARTH CIRCUIT.
IN the years 1836-'37, Prof. C. A. Steinheii, of Munich,
Germany, devised an electric telegraph; and in the latter year,
he constructed a line of wire from the Academy at Munich to
the observatory at Bogenhausen. He had constructed two
other lines, making three circuits of wires, but the whole were
arranged to be united into one common chain, to form an electric circuit. The first published notice made of this important
invention will be found in the third volume of'the Magazine
of Popular Sciences, in a letter from Munich, under date of December 23, 1836. This telegraph was announced in the
Comptes Rendu, in September, 1838.
In 1838, Prof. Steinheil made the important discovery of the
practicability of using the earth as one half or the returning
section of an electric circuit. The three lines, constructed as
hereinafter described, had double wires, so as to form a complete metallic circuit from and to Munich. Subsequent to the
erection of these experimental lines, the earth was discovered
to be a conducting medium in the formation of an electric
circuit, in conjunction with the wire stretched upon poles.
This was the grandest discovery ever made in practical telegraphy. The discoveries of Volta, CErsted, and Steinheil, are
to be considered as pre-eminent, in the consummation of the
electric telegraph. The first discovered the generating power,