In 1919, he invented a silent spring-driven clock.

Watches evolved from portable spring-driven clocks, which first appeared in 15th century Europe.

So spring-driven clocks slowed down over time as the mainspring unwound.

Achieving isochronism was recognised as a serious problem throughout the 500 year history of spring-driven clocks.

When spring-driven clocks were developed, which didn't require hanging weights to power them, they continued to be made in the bracket style.

He is mentioned in the city's records as the supplier of small spring-driven clocks, which were given as gifts to important people.

Although described here as using a driving weight it is equally applicable to spring-driven clocks and watches.

He also has turned a lifelong hobby into a small business - repairing weight- and spring-driven clocks.

What is the difference between a weight-driven and a spring-driven clock?

In spring-driven clocks and watches it required a fusee to even out the force of the mainspring.