Andrew Hilliard Atteridge,
Popular Science Monthly
(1874)
“ Again, even without occupying a station, it is possible to read the messages which are passing along a telegraph-line, and thus perhaps discover important secrets. All that is required for this purpose is a small portable receiving instrument, and a few yards of copper wire to connect it with the line. A single individual, thus equipped, can "tap" a telegraph-line, in the daytime, by receiving the message in the ordinary way ”
