N&W Agreement with Western Union Telegraph Co. ?

NW Mailing List nw-mailing-list at nwhs.org
Sat Mar 25 13:09:39 EDT 2017

Thanks, Mason.   That is a good lead.

There were only three telegraph wires on the Shenandoah Valley, from the time the line was opened in 1884, up until the end of the telegraph in the early 1960s.  Wire 1 was the Train Dispatcher's wire; Wire 2 was the Message wire; and if memory serves me correctly, Wire 205 was the Western Union wire.  (Will have to check my notes from Troy Humphries on the exact number for the WU wire.)  

When a telephone circuit was implemented for the Train Dispatcher (probably sometime before 1920,) the telephone circuit was probably "phantomed" on two of the existing telegraph wires.  Interestingly, the telephone was never suitable for Train Dispatching until the amplifier was invented, and the amplifier was not invented until after Lee Deforest's vacuum tube came into production around 1906-1907.  It was the invention of the vacuum tube which made the amplification of small currents possible.

And yes, "single wire with ground return" makes perfect sense.  The very first telegraph wire (Baltimore-Washington, May 1844) worked with one wire.  The battery was at Washington.  The positive side of the battery was hooked to the telegraph line, and the negative side was grounded to a large copper plate buried in the earth.  At the Baltimore end,  one side of the instruments was hooked to the wire, and the other side was connected to a large copper plate submerged in the Baltimore Inner Harbor.  Alfred Vail, the young "mechanician" [sic] who perfected the telegraph and worked the Baltimore end of the circuit that day, left copious notes and even a circuit diagram in his writings.  (Samuel F.B. Morse worked the instruments at the Washington end, but he was quite poor at anything technical and even had trouble hooking up the battery.)

The discovery that the earth (instead of a wire) could be used for one side of the circuit is credited to the great physicist, Karl August von Steinheil, born 1801.   Earth-return is the way all telegraph circuits were arranged up until AT&T needed some very sensitive long-lines polar circuits in the first couple decades of the Twentieth Century, for which cases a second copper wire was used instead of the earth.  Early telephones (1870s, 1880s) also used the "earth return" principle, but it was found that the "stray electrical potentials" in the earth ("earth currents," free electrons sloshing around in the ground, significantly affected by the sloshing around of the earth's molten iron core) distorted the tiny (unamplified) currents generated by a telephone microphone transmitter, and they had to go to the two-wire arrangement for telephone circuits to overcome this.

If this history of man's technology interests you, I suggest Frederick Leland Rhodes's 1929 work, Beginnings of Telephony (New York: Harper & Bros.)  Rhodes' focus is on the history of the technology, and he covers the entire gamut: the making of wire, the making of cable, overhead pole line, buried wires, the switchboard, the history of the development of telephone instruments, etc.  And the nice thing is, Rhodes "names names and gives dates," which is just what history guys like us want.

-- 73 SW &
(abram burnett)
                  Sent to You from my Telegraph Key
Successor to the MAGNETIC TELEGRAPH LINE of 1844

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