re
improvements in the telegraph. His more recent and more wonderful
inventions have thrown his telegraphic inventions into the shadow. On
the telegraph as invented by Morse but one message could be sent over
a single wire at one time. It was later discovered that two messages'
could be sent over the single wire in opposite directions at the
same time. This was called duplex telegraphy. Edison invented duplex
telegraphy by which two messages could be sent over the same wire in
the same direction at the same time. Later he succeeded in combining
the two, which resulted in the quadruplex, by which four messages
may be sent over one wire at one time. Though Edison received
comparatively little for this invention, its commercial value may be
estimated from the statement by the president of the Western Union
that it saved that company half a million dollars in a single year.
Edison's quadruplex system was also adopted by the British lines.

Before this he had perfected an automatic telegraph, work on which
had been begun by George Little, an Englishman. Little could make the
apparatus effective only over a short line and attained no very great
speed. Edison improved the apparatus until it transmitted thirty-five
hundred words a minute between New York and Philadelphia. Such is the
perfection to which Morse's marvel has been brought in the hands of
the most able of modern inventors.

VIII

TELEGRAPHING BENEATH THE SEA

Early Efforts at Underwater Telegraphy--Cable Construction and
Experimentation--The First Cables--The Atlantic Cable
Projected--Cyrus W. Field Becomes Interested--Organizes Atlantic
Telegraph Company--Professor Thomson as Scientific Adviser--His
Early Life and Attainments.

The idea of laying telegraph wires beneath the sea was discussed long
before a practical telegraph for use on land had been attained. It
is recorded that a Spaniard suggested submarine telegraphy in 1795.
Experiments were conducted early in the nineteenth century with
various materials in an effort to find a covering for the wires which
would be both a non-conductor of electricity and impervious to water.
An employee of the East India Company made an effort to lay a cable
across the river Hugli as early as 1838. His method was to coat the
wire with pitch inclose it in split rattan, and then wrap the whole
with tarred yarn. Wheatstone discussed a Calais-Dover cable in 1840,
but it remained for Morse to actua