he writing is thus traced by means of
a series of minute perforations in the sheet, from which, as a stencil,
hundreds of copies can be made. Such stencils can be prepared on
typewriters. Edison elaborated this principle in two other forms--one
pneumatic and one electric--the latter being in essence a reciprocating
motor. Inside the barrel of the electric pen a little plunger, carrying
the stylus, travels to and fro at a very high rate of speed, due to the
attraction and repulsion of the solenoid coils of wire surrounding it;
and as the hand of the writer guides it the pen thus makes its record
in a series of very minute perforations in the paper. The current from
a small battery suffices to energize the pen, and with the stencil thus
made hundreds of copies of the document can be furnished. As a matter
of fact, as many as three thousand copies have been made from a single
mimeographic stencil of this character.

CHAPTER IX

THE TELEPHONE, MOTOGRAPH, AND MICROPHONE

A VERY great invention has its own dramatic history. Episodes full of
human interest attend its development. The periods of weary struggle,
the daring adventure along unknown paths, the clash of rival claimants,
are closely similar to those which mark the revelation and subjugation
of a new continent. At the close of the epoch of discovery it is seen
that mankind as a whole has made one more great advance; but in the
earlier stages one watched chiefly the confused vicissitudes of fortune
of the individual pioneers. The great modern art of telephony has had
thus in its beginnings, its evolution, and its present status as a
universal medium of intercourse, all the elements of surprise, mystery,
swift creation of wealth, tragic interludes, and colossal battle that
can appeal to the imagination and hold public attention. And in this
new electrical industry, in laying its essential foundations, Edison has
again been one of the dominant figures.

As far back as 1837, the American, Page, discovered the curious fact
that an iron bar, when magnetized and demagnetized at short intervals
of time, emitted sounds due to the molecular disturbances in the mass.
Philipp Reis, a simple professor in Germany, utilized this principle in
the construction of apparatus for the transmission of sound; but in the
grasp of the idea he was preceded by Charles Bourseul, a young French
soldier in Algeria, who in 1854, under the title of "Electrical
Telephony," in a Parisian illus