Ke (unit)
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The ke (刻; pinyin: kè) is a traditional Chinese unit of decimal time lasting approximately a quarter of a western hour. Traditionally the ke divides a day into 100 equal intervals[1] of 14.4 minutes (14 m 24 s). The ke is equivalent to the centiday (cd), a non-SI unit accepted for use with SI. Ke literally means 'to etch' or 'to cut', and it is part of the noun Kedu which refers to etched-on markings on measuring devices.[citation needed]
Alongside the ke, the ancient Chinese kept time with double hours (traditional 時辰, simplified 时辰, pinyin shíchen) also known as watches. Because one cannot divide 12 double hours into 100 ke evenly, each ke was subdivided into 60 fen (分; pinyin fēn).
There were various attempts to redefine the ke to 96, 108, or 120 so as to divide evenly into 12 double hours. During the Qing dynasty around the time of the arrival of Jesuit missionaries, the duration of the ke was finally redefined to one-ninety-sixth of a day, or exactly one fourth of a western hour. Today ke is still commonly used in China to refer to a quarter of an hour.
The French revolutionaries in the 18th century were unaware of the successful adoption of decimal time using the ke and did not utilize the familiar quarter of an hour in their reforms.
[edit] Notes
- ^ According to the Shuowen Jiezi from Xu Shen, “漏以铜壶盛水，刻节，昼夜百刻。” Translation: “Drop waters from a copper/bronze container with water inside. The time spent is measured. We can thus divide a whole day into 100 measures.”
[edit] References
- Ronan, Colin p 247-250 in Walker, Ch. ed.: Astronomy before the telescope. Brit. Museum P., UK (1999). ISBN 0-7141-2733-7
