The Japanese Clocks and Time in the Past : Non-standard Seasonal Time Inscribed on Scale Plates of Foot-Ruler Clocks

• HASHIMOTO Takehiko

  Department of History and Philosophy of Science, University of Tokyo

抄録

This paper explains the recent discovery by the author of a unique time-counting system inscribed on the scaled plates of the foot-ruler clocks preserved at the Seiko Museum in Tokyo. The time system, adopted by the Tokugawa government in the Edo period, was a seasonally variable one. The lengths of daytime and nighttime, both composed by six units of time, differed each other and varied throughout the year. However, according to the official time system, the daytime as well as the nighttime were divided into equal units of time. The scale plates (called setsuita) of the foot-ruler clocks at the Seiko Museum indicate that daytime was divided into unequal parts of time: longer parts in the morning and the evening, and shorter parts in between. The ratioof the lengths of the daytime and the nighttime also differed from those designated by the official time system. The author will conclude with a suggestion on the historical implication of a new finding that relates to the manner in which time bells were tolled.

収録刊行物

• Historia scientiarum. Second series : international journal of the History of Science Society of Japan

  Historia scientiarum. Second series : international journal of the History of Science Society of Japan 22 (1), 22-39, 2012-07-31

  日本科学史学会

キーワード

• Wadokei
• Japanese Clock
• Foot-ruler Clock
• Setsuita
• Seasonal Time System
• Time Bell

詳細情報

• CRID: 1571698602796193152
• NII論文ID: 110009488995
• NII書誌ID: AA11081495
• ISSN: 02854821
• 本文言語コード: en
• データソース種別:
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