英文资料在此,让陈兄来翻译吧:
Ulysse Nardin, Locle, Suisse, sequential pair of solar and sidereal deck-watches, 56mm, matching heavy sterling silver (.925 marked) OF original SB&B cases, SW-pin-set, matching WEDs with outer chapters divided in fifths of seconds, lever escapements with Guillaume balances, capped escape wheels, serial numbers on dial plates next to balances, 19-20J, gilt mvts, s#124140 (sidereal) and s#124141 (solar), case numbers also sequential at s#620768 (sidereal) and s#620769 (solar). While the watches bear no indications of their different timekeeping, when presented with a sequentially numbered pair we immediately tested to see if there was a difference in timekeeping. A sidereal timekeeper runs through 24 sidereal hours in roughly 23 hours, 56 minutes and 4 seconds of solar time, thereby gaining 3 minutes and 56 seconds per diem, or about 9.83 solar seconds per hour. Solar time is based on the average of daily rotation of the earth around the sun on a 24-hour scale, while sidereal time is based on the average daily rotation of the earth with respect to the fixed background of stars, so distant as to appear not to move at all relative to the earth's orbit around the sun. While the earth may rotate roughly 365.25 times per year as we see it, it has an additional rotation caused by its orbit about the sun, that we do not perceive, relative to the universe. So while a solar timepiece will, on average and in simplification, show the sun passing directly overhead at noon, the sidereal timekeeper will show the same star passing directly overhead at the same sidereal time every day, hence the use in astronomy. Timekeepers only show averages, or mean times, with the sidereal timekeeper actually keeping closer to an "absolute" mean time, equally meaningful under all observations. Solar mean time, calculated without time zones, will only coincide with the sun passing directly overhead at noon four times a year, the deviation of all the other days forming the "equation of time." When local solar mean time is lumped into a time zone, its meaning becomes socioeconomic moreso than scientific, although its average seconds will be the same regardless of the nominal local time. And that is just the simple version - see Derek Howse, "Greenwich Time and the Discovery of the Longitude" for a brilliant description of different times and timekeeping systems right up to the present day. To find an original sequential pair of timepieces is quite rare, and the regulation to the two mean-time systems is a plus; at the same time it is not complicated for the expert to convert a balance from one system to the other, the change established by the addition or subtraction of an approximate four-minute timing washer pair, or movement inwards or outwards of timing screws. This pair is in oustanding condition. Gross weight of assembled sidereal watch 109.6 dwt (170.4 g), solar 108.2 dwt (168.3 g).