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The Western
Union Telegraph Company "broadcast" a time signal to its central offices
once daily at an appointed time. The signal was one click on the telegraph
wires. It originated at the US Naval Observatory.
The signal
was relayed to distant clocks in subscriber's offices as a "synchronizing"
impulse which energized the electromagnets located on the upper right
of the clock movements. Linkage from the electromagnets and heart-shaped
cams forced the hands precisely to the hour. Thus, all subscriber's clocks
were "in-sync" with the Naval Observatory.
The long
case wall clock shown here is an 80 beat (3/4 seconds) example which could
have had an advertisement displayed in the lower half. Similar models
had special hourly contacts and were used in smaller Western Union Central
Offices as primary standards.
Similar clocks
were offered for sale by the Self Winding Clock Company with or without
the synchronization mechanism. They are fine and accurate timepieces even
without the hourly synchronizing signal offered by Western Union Telegraph
Company.
The two wall
clocks below represent the office clocks offered for rent by Western Union,
although owned and manufactured by the Self Winding Clock Company. They
have either 120 (1/2 second) or 140 beat short pendulum escapement style
F movements. The model with the second hand cost fifty cents more per
month than the smaller dial. Included with the service was an annual replacement
of the 2 dry cell batteries inside.
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