The chronometer collection features Marine Chronometers, Deck Watches and Pocket Chronometers as well as timers and chronographs that were intended for navigational purposes.
The most important impetus to the development of timekeeping in the 18th and 19th centuries was the quest for longitude. The Arnold & Son pocket chronometer in the collection is a good if imperfect example of this period when the pioneering work of Harrison with H4 was being reduced to common practice, albeit in different form, by Arnold and Earnshaw with significant support from the English and French horological communities.
This effort retained its momentum throughout the 19th century and there are several examples of English pieces from this period.
The final development of the chronometer was the work of Hamilton and the less successful but equally interesting work by Elgin during the Second World War. Many of Hamilton's improvements eventually found their way into pocket watches in the 950B and 992B and their related military issues.
The detent chronometer escapement has always been the mechanism of choice for a durable precise rate needed for navigation, but it does not allow for adjustment to positions and rough usage required for some military applications. Very high grade lever watches have been the mechanism of choice for these applications and in some cases, the Swiss have produced examples that outperform high quality chronometer escapements.
The Kirova Russian chronometer is the only lever example. Nardin also made a very fine lever escapement marine chronometer but I do not own one. Most of the deck watches are lever escapements.
The "Other Instruments" link displays a small collection of sextants, compasses and altimeters.