Historical development of water-powered mechanical clocks

Zheng Hui Hwang, Hong Sen Yan, Tsung Yi Lin

Research output: Contribution to journalArticlepeer-review


This article examines the historical development of ancient water-powered mechanical clocks. The study begins with a comprehensive analysis and comparison of the different types of ancient clepsydra, their use and development and the development of their feedback systems, power systems, and time-reporting systems. Before becoming mechanized, water clocks (clepsydra) were mainly used for astronomical timekeeping, during religious sacrifices, for military affairs, court litigation timekeeping, and the time allocation of water rights. The invention of the feedback system in the 3rd century before common era (BCE) opened the door to the mechanization of water clocks. The float is the earliest power-driven element. In the 8th century, the emergence of waterwheels with timing functions in water-powered mechanical clocks prompted ancient China to develop water-powered mechanical clocks with waterwheel steelyard clepsydra devices, time-reporting devices, astronomical demonstration devices, and multiple time-reporting wooden pavilions. After the 13th century, mechanical clocks started to integrate elements from Chinese and Western cultures. In addition to the development of new styles of water-powered mechanical clocks in ancient China, the Western mercury wheels with timing functions evolved into compartmented cylindrical mercury clocks.

Original languageEnglish
Pages (from-to)203-219
Number of pages17
JournalMechanical Sciences
Issue number1
Publication statusPublished - 2021 Feb 19

All Science Journal Classification (ASJC) codes

  • Control and Systems Engineering
  • Civil and Structural Engineering
  • Mechanics of Materials
  • Mechanical Engineering
  • Fluid Flow and Transfer Processes
  • Industrial and Manufacturing Engineering

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