[time-nuts] The need for quartz crystals and mains frequency (was: Mains Frequency)

[Hal Murray]

attila at kinali.ch said:
> And, please do not forget that modern mains frequency control is something
> quite recent as well. Especially outside (west) Europe. Having mains
> frequency powered clocks being off several minutes per month was the norm
> 50-70 years ago.

I have a (fuzzy) data point from ~60 years ago.

I was in high school and got to tag along with a quick tour through Niagara 
Mohawk's control room.  They were the power company for a large part of 
upstate New York, including Syracuse where I lived.

I remember somebody pointing out a pair of clocks on the wall, one driven by 
the line.  I wasn't enough of a time-nut to inquire about the source for the 
reference clock.

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Has anybody seen a good writeup on the history of clocks running off the line 
frequency and power lines being used for timekeeping?

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Anybody else remember the little red dot that was on a swinging flag behind a 
little hole?  That was the analog equivalent of blinking 00:00.

When you set the time on a clock, the flag swung up and stuck to a magnetic 
part of the motor.  The color on the part of the flag visible through the hole 
in that position matched the color of the face.  When power was lost, gravity 
pulled the flag down and that part was painted red.


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