This is a chronometer (a ships deck watch) designed to be used on a ship.
Accurate timekeeping was an essential part of navigating. This watch came top in a trial of 83 watches at the Royal Observatory in Greenwich in 1902 and was used on various Royal Navy ships until 1948.
This watch has a 'karrusel escapement' - a ground-breaking design which enabled the watch to keep time even if it was shaken about. This type of escapement was invented by Bahne Bonniksen, who taught Horology to apprentice watchmakers at Coventry Technical Institute.