Accompanied by Ulysse Nardin original Bulletin de Marche dated July 1950 confirming the adjustment of the movement to sidereal time.
"Break-Circuit" deck watches were designed to assist in surveying and mapping operations as well as solar observations and scientific experiments in remote areas requiring precise and audible time signals. These deck watches, also called survey chronometers, were highly finished and adjusted in order to meet the surveyor's and scientific's requests.
The first break-circuit mechanism was installed in 1874 by S. & J.D. Negus, Chronometer and Nautical Instruments Makers in New York.