This 18-carat gold fob watch with key and chain was made by Benjamin Vulliamy (1780-1854) of London. It has a normal minute hand for showing mean time and an additional minute hand for local time. It also has a table inside the back of the case which shows the differences from Greenwich time for a number of English and European cities. Vulliamy was royal clockmaker to King George IV, King William IV and Queen Victoria.
© Science Museum / Science & Society Picture Library