The need to gauge the divisions of the day and night led the ancient Egyptians, Greeks and Romans to create sundials, water clocks and other early chronometric tools.

• 古埃及人、希腊人与罗马人为了测定昼夜之别，发明了日晷、水钟及其他早期计时工具，后来由西方世界继承了这些技术。