You may be interested in a thread here earlier this year titled "Absolute time accuracy pre-Cesium?" starting March 25. Also, look for references to John Harrison in the archives. There's a video showing several of his clocks running with the grasshopper escapement, and one of his long clocks being taken apart. http://lists.febo.com/pipermail/time-nuts_lists.febo.com/
On Wed, Nov 20, 2019 at 8:00 PM Philip Gladstone <[email protected]> wrote: > > I've started to monitor the individual ticks on a grandfather clock from > the 1790s. Essentially I timestamp whenever the pendulum breaks/restores a > light beam. > > The data that I get is surprising in that the pendulum swing varies > according to the position of the hands on the clock. It appears that the > amplitude of the swing depends on the driving force imparted by the > escapement. Since the second hand is not counterweighted, there is slightly > more energy available to drive the escapement during the first half of each > minute and slightly less in the second half. There is much bigger effect at > the end of each hour when the mechanism has to move a lever to trigger the > strike mechanism. This 'end of hour' effect changes the pendulum swing > enough so that the period is noticeably affected (maybe by 300ppm) > > Anyway, my google-fu did not reveal anybody else interested in this > stuff... Anybody here interested? > > Philip > _______________________________________________ > time-nuts mailing list -- [email protected] > To unsubscribe, go to > http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com > and follow the instructions there. _______________________________________________ time-nuts mailing list -- [email protected] To unsubscribe, go to http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com and follow the instructions there.
