Re: Telegraph Components

Mr. Holmes has provided good information on a regular earth-return Morse telegraph circuit. They were series DC circuits...One station sending would be heard on the sounders at all other stations
simultaneously.,

If the wire failed "open" at any point, all communication was stopped until the break was located and repaired. With the "terminal battery"divided between the two ends, a hard"ground"out in the middle of the circuit somewhere would effectively stop end-to-end communication, while each half of the circuit would work pretty much normally. The reason for dividing the terminalbattery between the ends of a circuit had to do with improving operation of the circuit during wet weather.

Leakage losses from broken insulators or trees and brush in the line would affect circuit operation to varying degrees, as would wet weather. That is why the mainline relays had a variable magnetic
gap adjustment. This would need to be adjusted from time to time to counteract the current leakage and make the signals come clear.

Automatic repeaters were used to extend circuits where necessary and avoid operators at relay offices having to copy and resend messages manually. Repeaters were also used where one circuit needed to "branch" off from another if the branch was too long to just use a loop off the main circuit,

T