History of timekeeping devices in Egypt
The
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.Sundials and shadow clocks
Despite Herodotus's attribution of the invention of the sundial to the Babylonians in 430 BCE, the earliest known sundials were simple gnomons of Egyptian origin invented around 3500 BCE [citation needed]. More complex devices were developed over time, the earliest surviving one is a limestone sundial that dates back to 1500 BCE, discovered in the Valley of the Kings in 2013.[3] It was found in a housing area of construction workers and its division of daytime into 12 parts was possibly used to measure work hours.[3]
Shadow clocks were modified sundials that allowed for greater precision in determining the time of day, and were first used around 1500 BCE.
Merkhets
Using plumb-lines called merkhets, the Egyptians could calculate time at night, provided the stars were visible.[1][2] Used since at least 600 BCE, two of these instruments were aligned with Polaris, the North pole star, creating a north–south meridian.[1][2] By observing certain stars as they crossed the line created with the merkhets, they could accurately gauge time.[1][2]
See also
References
- ^ a b c d e f g "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.
- ^ ISBN 978-0-19-285211-3.
- ^ Science Daily. 2013-03-14. Retrieved 2017-03-14.