Discipline a grandfather clock with a Caesium fountain clock

Via Hackaday I found this posting by Daniel Valuch from CERN, who uses CERN’s Caesium fountain clock to discipline his grandfather clock.

Read the article, it’s dang funny, some excerpts which made me pee my pants laughing:

So we were left with the pendulum equation T=2*pi*sqrt(L/g) where T is the pendulum swing period, L length of the pendulum and g the gravitational acceleration. Changing the 2, or π is difficult even for CERN. So we are left with g, and L.

Or:

[…] the path changing the gravitational acceleration was well in reach. Should we assume the 0.1 sec/day specification, the clock would needed to be displaced vertically by not more than 3-4 storeys to obtain the required tuning range for PLL (phase locked loop) by working on the gravitational acceleration.