Holy Trinity Church

Anglican worship in Geneva

The Clock – back in action

Geneva, February 2, 2018

 In case it has escaped the notice of any of Holy Trinity’s congregation, the church clock is telling the time, for the first time since October 17, 2014, when it was removed for restoration at Geneva’s horological school.

The clock has in fact been ticking unnoticed since before Christmas, but it was only on January 19, 2018 that the mechanism was connected to the hands on the dial and the 150-year-old clock resumed its public duty, without fanfare.

The gleaming, newly restored clock is now resplendent as a functional exhibit in its tall glass case in the clean and refurbished clock tower — a far cry from the dingy, dusty surroundings in which a grimy old clock laboured uncertainly three and a half years ago.

The clock restorer, M. Jean-Pierre Curchod, is currently monitoring the performance of the clock, notably its rate — how much it gains or loses a day. He needs to know this to synchronise the clock with an electronic timekeeper. This works by setting the clock to run fast. As soon as it accumulates a certain gain — 20 seconds for example, an amount discernable on the dial — a magnet extends to stop the pendulum. The magnet then releases the pendulum to the time of the electronic clock.

M. Curchod will have to work out how fast to set the clock, how often to synchronise the time and when, and for how long to stop the clock each time. This will depend on the regularity of the rate, how much, for example, does the clock lose in summer when warmth expands the pendulum and makes the clock go slower. Then there’s the question of the shift between summer and winter time — determining the best time to reset the clock for the minimum disruption.

All these data need to be collected and programmed into the chip that runs the automatic time setting system. This means that M. Curchod will be periodically in and out of the tower for the next 12 months, accommodating the rigid time setting system to the variable frequency of the 150-year-old clock.

Much simpler is the automatic winding system. Currently an electric motor hoists the weight that drives the clock every 24 hours at 13:10. So far it is working well, but since the clock will go for eight days without rewinding, there is considerable redundancy.

The automatic winding and setting systems are totally reversible and can be overridden any time by winding and setting the clock manually.

Meanwhile, M. Curchod is preparing a book about the clock, including its history and the technical details of its restoration. It is destined as a guide to the future maintenance and restoration of a clock that was designed and built to last for centuries.

As M. Curchod points out, the newly restored mechanical clock will certainly outlast the electronic gadgetry that surrounds it.