The History of the Pocket Watch

Pocket watches were the first portable timepiece, predating wrist watches by about 400 years.

The inner workings of watches were developed when coiled (spiral) springs were used as power sources. At around 1500 in Nürnberg, Germany, Peter Henlein (1480-1542), invented a portable time piece which he named the Nürnberg egg, which was a forerunner of today's pocket watch.

Nürnberg eggs were oval in shape and much bigger than today's discretely sized pocket watches, measuring around 12 cm in diameter and with a depth of 7cm. These eggs has an hour hand only - the minute hand was not introduced until around 1660. They also had no glass face to protect them - this did not come until around the start of the 17th century.

Because of their size and innaccuracy, (they slowed down as the coiled spring unwound), these "eggs" were used more as ornaments than timepieces, as they were quite beautiful.

In a time before precision machinery, it was a highly skilled craft to create and build accurate timepieces. Local guilds were set up to control clock building and apprenticeships, including the "Paris Guild of Clockmakers" and the "London Clockmakers Company".

There is some controversy over who first invented the balance spring, which allowed watches to stay accurate to within a few minutes per day. It was invented around 1670 by Christian Huygens (1625-1695) or Robert Hooke (1635-1703). Perhaps they both came up with the same idea independently? There were heated exchanges between these two characters at the time!

The balance spring improved accuracy by creating a stable oscillation of the balance wheel, which allowed the power to be consistently released by the mainspring, and avoiding the slowing towards the end of the wind of the earlier models.

Further improvements to accuracy included the machine cutting of wheels, instead of hand cutting, and other refinements.