Hi Bruce: Yes, I saw a mention of that. Sort of like crystal frequency jumps.
Have Fun, Brooke Clarke http://www.PRC68.com http://www.precisionclock.com Dr Bruce Griffiths wrote: > Brooke Clarke wrote: > >>Hi Mike: >> >>Back in the 1800s clock makers found ways to temperature compensate the >>pendulum such as putting a Mercury thermometer at the bottom, using metals >>with >>dissimilar expansion coefficients (Harrison used steel and bronze (no zinc >>then)) or materials with almost zero COE like Invar. >> >>The Dent clock at Greenwich in 1885 had an arenoid type compensator to remove >>barometric pressure effects, later clocks were run in vacuum. >> >>Have Fun, >> >>Brooke Clarke >>http://www.PRC68.com >>http://www.precisionclock.com >> > > Brooke > > Invar and super Invar sound OK except that they are notoriously unstable > with the dimensions changing slowly over time even at constant temperature. > > Bruce > > _______________________________________________ > time-nuts mailing list > time-nuts@febo.com > https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts > _______________________________________________ time-nuts mailing list time-nuts@febo.com https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts