A timepiece that accompanied Charles Darwin during his voyage on the HMS Beagle has had an export bar placed on it, ...

It performed well enough for Harrison to be granted £500 from the Longitude Board to develop it. The chronometer invented by John Harrison in 1737, which enabled mariners to chart their longtitude.

Among the notable contenders was John Harrison, a self-taught clockmaker whose marine chronometer, H4, eventually claimed the prize in 1765. Harrison’s marine chronometer revolutionized navigation.

At a dinner at 10 Downing Street, astronaut Neil Armstrong, not long after his walk on the moon, gave a toast to Englishman John Harrison, inventor of the marine chronometer.

His marine chronometer was used by sailors to accurately measure a ship's position at sea, as well as to tell the time. By the time he reached his 20s he was producing long-case clocks.