4 ms·

I haven't ever seen mention of elaborate suspension systems to counteract the effect of people walking about or seismic activity. Given that I had a modest inte

I haven't ever seen mention of elaborate suspension systems to counteract the effect of people walking about or seismic activity. Given that I had a modest interest in old clocks I would take this is a reasonable indication that it is not a problem or that what problem exists cancels itself out. If I had to take a guess the reason is the only coupling through to the pendulum would be via the friction in its bearings or via movement of the air around it. Both of these are naturally minimised in most designs so normal vibrations are not an issue.

fanf2 6y ago
On this page about a reconstruction of Harrison’s longitude clock http://leapsecond.com/pend/clockb/ http://leapsecond.com/pend/clockb/ there’s a presentation “a close look at Clock B”. Slide 63 lists “environmental effects”, which suggests normal vibrations are a problem for precision clocks. It says: Long-term performance depends on: – temperature (absolute, relative, gradient) – atmospheric pressure, air currents – humidity – shock & vibration (air, ground, wall) – material stability or other disturbances – energy loss stability & energy gain stability
- VBprogrammer 6y ago
  I think the magnitude of vibrations felt on a ship in calm seas probably are an order of magnitude more than a stationary clock. Perhaps that is why it rates a mention here. While I'm not trying to claim it has no effect, the effect must be slight enough as to be negligible, otherwise we'd have seen some kind of compensation as we see compensation for temperature, spring tension etc. Perhaps I'm underestimating it though and the reason this is not compensated for is simply that these where the atomic clocks of their time. They would represent a significant investment, no idiot would install it in a building set back from a major truck road or expect to be able to run tap dancing classes in the room above. It's quite likely that the manufacturer set out standards for the building it was installed within, perhaps even down to the type of foundations it had to have.
  - fanf2 6y ago
    Sorry, I misspoke, Clock B was a land clock designed after the marine chronometer H4. Pendulum clocks don’t work at sea.

fanf2 6y ago

On this page about a reconstruction of Harrison’s longitude clock http://leapsecond.com/pend/clockb/ http://leapsecond.com/pend/clockb/ there’s a presentation “a close look at Clock B”. Slide 63 lists “environmental effects”, which suggests normal vibrations are a problem for precision clocks. It says: Long-term performance depends on: – temperature (absolute, relative, gradient) – atmospheric pressure, air currents – humidity – shock & vibration (air, ground, wall) – material stability or other disturbances – energy loss stability & energy gain stability

VBprogrammer 6y ago
I think the magnitude of vibrations felt on a ship in calm seas probably are an order of magnitude more than a stationary clock. Perhaps that is why it rates a mention here. While I'm not trying to claim it has no effect, the effect must be slight enough as to be negligible, otherwise we'd have seen some kind of compensation as we see compensation for temperature, spring tension etc. Perhaps I'm underestimating it though and the reason this is not compensated for is simply that these where the atomic clocks of their time. They would represent a significant investment, no idiot would install it in a building set back from a major truck road or expect to be able to run tap dancing classes in the room above. It's quite likely that the manufacturer set out standards for the building it was installed within, perhaps even down to the type of foundations it had to have.
- fanf2 6y ago
  Sorry, I misspoke, Clock B was a land clock designed after the marine chronometer H4. Pendulum clocks don’t work at sea.