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07 Dec 2010 [23:00]
sealed up the pendulum chamber with tape, thanks to Hilary Costello for help. Note that pendulum amplitude drops straight away - a good sign. The amplitude rapidly settles to a steady value overnight. The test will be at 8am tomorrow - will there be a glitch in amplitude? I hope not.
07 Dec 2010 [08:00]
Recently there have been sudden shifts in pendulum amplitude starting at around 8am every day. I suspect this is when the heating comes on, or perhaps when the cleaning lady opens the door in the room below. It is regular as clockwork on weekdays (see today(Tuesday) [link] and yesterday [link] but note that there was no glitch on Sunday [link]). Whatever the cause, recent cold weather has highlighted the variability of pendulum amplitude with air temperature. There is a cold draft coming out of the cracks around the door of the pendulum chamber so perhaps air currents around the pendulum are to blame. Suspected this for ages, so maybe tonight I should
07 Dec 2010 [07:59]
seal up the gaps and find out.

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