Important Collectors' Wristwatches, P...

Geneva, May 08, 2010

LOT 412

F. Bovet & Co. Two Time Zone & Independent Dead Center-Seconds F. Bovet & Co., Bienne, No. 16064 / 11070. Made circa 1860. Very fine and rare, 18K yellow gold, two-train, two-time-zone pocket watch with independent dead center-seconds. Accompanied by a rosewood fitted box and yellow gold ribbon fob.

CHF 4,000 - 6,000

USD 3,800 - 5,700 / EUR 2,800 - 4,200

C. Four body, "bassine et filets", the back engraved with a seventeenth century Dutch interior scene, bolt at 6 to lock the center seconds, coinedge band. Hinged gold cuvette engine-turned and engraved with the technical details. D. White enamel with two meantime dials, one with radial Roman numerals and outer minute track, the other with Arabic numerals and outer minute track, subsidiary constant seconds, outer seconds track. Blued steel hands. M. 43 mm., 20''', frosted gilt, 22 jewels, two-train with separate winding, counterpoised lateral lever escapement, notched bimetallic compensation balance, blued steel flat balance spring, index regulator. Punched « FB » on the dial plate. Diam. 49 mm.


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Grading System
Grade: AA

Very good
Case: 3

Good
Movement: 3*

Good

Overhaul recommended, at buyer's expense
Dial: 3-75-06

Good

ENAMEL AND VARIOUS TYPES OF DECORATION Slightly restored soft enamel

HANDS Partially replaced

Notes

(Lots 411 and 412) Both these watches are extremely unusual because they feature a provision for two independently adjustable time zones before the adoption of hourly time zones. Lot 411 additionally has a pivoted detent chronometer escapement; lot 412 features independent dead center seconds. Before the adoption of time zones, people used local solar time (originally apparent solar time, as shown by a sundial) and, later, mean time. Mean time is the average over a year of apparent solar time; its difference from apparent solar time is the equation of time. As railways and telecommunications flourished, the fact that time in various places differed according to the difference in their longitude became a problem. This could have been solved by universally synchronizing clocks, but then in many places local time would differ markedly from the solar time to which people are accustomed. Time zones for the entire world were first suggested in 1876 by Canadian Sir Sandford Fleming. He suggested a single 24-hour clock (to be located at the center of the Earth and not linked to any surface meridian). In 1879 he specified that his universal day would begin at the Greenwich meridian (now 180°), while conceding that hourly time zones might have limited local use. Although the International Meridian Conference of October 1884 did not adopt his time zones, it did adopt a universal 24-hour day beginning at Greenwich midnight, specifying that it "shall not interfere with the use of local or standard time where desirable". Nevertheless, by 1929 most countries had adopted hourly time zones. Today, all nations use standard time zones, but all do not apply the concept as originally conceived.
Greenwich Mean Time (GMT) Was established in 1675, when the Royal Observatory was built, as an aid to determining longitude at sea. The first time zone in the world was established by British Railways on December 1, 1847 - with GMT hand-carried chronometers. About August 23, 1852, time signals were first transmitted by telegraph from the Royal Observatory in Greenwich. Although 98% of Great Britain's public clocks were using GMT by 1855, it did not become Britain's legal time until August 2, 1880.