The ancient Egyptians were one of the first cultures to widely divide days into generally agreed-upon equal parts, using early timekeeping devices such as sundials, shadow clocks, and merkhets (plumb-lines used by early astronomers).[1][2] Obelisks were also used by reading the shadow that they make[citation needed]. The clock was split into daytime and nighttime, and then into smaller hours.
- ^ "Early Clocks". A Walk Through Time - The Evolution of Time Measurement through the Ages. National Institute of Standards and Technology. 12 August 2009. Retrieved 2022-10-13.
- ^ Whitrow, G. J. (1989). Time in History: Views of Time from Prehistory to the Present Day. Oxford University Press. p. 28. ISBN 978-0-19-285211-3.