Abstract
THE problem of the determination and distribution of accurate time has been advanced considerably in recent years by the use of the moving wire in observing transits, and the introduction of wireless time-signals. Hence the analysis of the behaviour of high-class time-keepers under various conditions, which is dealt with in this memoir, is likely to be of general utility. Mr. Sôtome notes that chronometers are essential in Japanese observatories as a supplement to pendulum clocks, on account of the prevalence of earthquake shocks, which produce abrupt changes on the error and rate of a clock, but have no sensible effect on a chronometer. It is shown that the chronometer rates are sensitive to changes of atmospheric pressure and humidity, so that an air-tight case should be used. Most of the chronometers showed perceptible change of rate according to the interval that had elapsed since winding; this change was diminished by using a falling weight instead of a spring as motive power, a method that is practicable in an observatory, but not at sea.
Annales de l*Observatoire astronomique de Tokyo.
Tome 5, 4e fascicule. Studies on Astronomical Time-Keepers and Time-Preserving Systems. By Kiyofusa Sôtome. Pp. ii + 59. (Tokyo: Imperial University, 1921.)
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CROMMELIN, A. Annales de l'Observatoire astronomique de Tokyo . Nature 108, 175 (1921). https://doi.org/10.1038/108175a0
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DOI: https://doi.org/10.1038/108175a0