[time-nuts] Pendulums & Atomic Clocks & Gravity

Mike S mikes at flatsurface.com
Sat May 26 21:03:51 EDT 2007

At 07:49 PM 5/26/2007, Brooke Clarke wrote...
>Back in the 1800s clock makers found ways to temperature compensate 
>pendulum such as putting a Mercury thermometer at the bottom, using 
>metals with
>dissimilar expansion coefficients (Harrison used steel and bronze (no 
>then)) or materials with almost zero COE like Invar.
>The Dent clock at Greenwich in 1885 had an arenoid type compensator to 
>barometric pressure effects, later clocks were run in vacuum.

Does your clock (you only stated you were adjusting the bob on a 
pendulum clock) have either feature? The vast majority, I would hazard 
to say, don't. 

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