lthough the electric telegraph is, comparatively speaking, a recent
invention, yet methods of communication at a distance, by means of
signals, have probably existed in all ages and in all nations. There
is reason to believe that among the Greeks a system of telegraphy was
in use, as the burning of Troy was certainly known in Greece very soon
after it happened, and before any person had returned from Troy.
Polybius names the different instruments used by the ancients for
communicating information--"pyrsia," because the signals were always
made by means of fire lights. At first they communicated information
of events in an imperfect manner, but a new method was invented by
Cleoxenus, which was much improved by Polybius, as he himself informs
us, and which may be described as follows:

Take the letters of the alphabet and arrange them on a board in five
columns, each column containing five letters; then the man who signals
would hold up with his left hand a number of torches which would
represent the number of the column from which the letter is to be
taken, and with his right hand a number of torches that will represent
the particular letter in that column that is to be taken. It is thus
easy to understand how the letters of a short sentence are
communicated from station to station as far as required. This is the
pyrsia or telegraph of Polybius.

It seems that the Romans had a method of telegraphing in their walled
cities, either by a hollow formed in the masonry, or by a tube fixed
thereto so as to confine the sound, in order to convey information to
any part they liked. This method of communicating is in the present
age frequently employed in the well known speaking tubes. It does not
appear that the moderns had thought of such a thing as a telegraph
until 1661, when the Marquis of Worcester, in his "Century of
Inventions," affirmed that he had discovered a method by which a man
could hold discourse with his correspondent as far as they could
reach, by night as well as by day; he did not, however, describe this
invention.

Dr. Hooke delivered a discourse before the Royal Society in 1684,
showing how to communicate at great distances. In this discourse he
asserts the possibility of conveying intelligence from one place to
another at a distance of 120 miles as rapidly as a man can write what
he would have sent. He takes to his aid the then recent invention of
the telescope, and explains how characters exposed at one s