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A Walk Through Time - The Evolution of Time Measurement through the Ages

a walk through time

Copyright: Readers should note that, because this is a publication of the National Institute of Standards and Technology, the text and images in this short treatise are not subject to copyright, and may be reproduced and used without consideration for copyright regulations. However, it would be appreciated if users acknowledged this web site as a source of information.

Example of how to reference this online database:
K. Higgins, D. Miner, C.N. Smith, D.B. Sullivan (2004), A Walk Through Time (version 1.2.1). [Online] Available: [2010, July 12]. National Institute of Standards and Technology, Gaithersburg, MD.
Citation Form:
Author/editor (Year), Title (edition). [Type of medium] Available: URL [Access date].

Version 1.2.1
November 2004
The date for the earliest Egyptian calandar was modified and a reference was added.
Version 1.2
April 2002
Substantial revision by Collier N. Smith, with much valuable input and advice from Donald B. Sullivan, chief of the Time and Frequency Division.
Version 1.1
August 1997
Graphical layout designed and created by Johnathan Coursey and Michael Douma.
Version 1.0
May 1995
Adapted to HTML by G. Wiersma and M. Hane.
Earlier Publication
August 1992
Based on the K. Higgins, D. Miner, "A Walk Through Time," Department of Commerce Publication
Publication History
~ 1975
This brief essay on the history of timekeeping was conceived and written by Kent Higgins and illustrated by Darwin Miner, of the Program Information Office of the National Bureau of Standards (now NIST) in about 1975, and printed in booklet form for distribution to visitors to the Boulder Laboratories. It was reprinted several times, with small revisions principally by Collier N. Smith, over the next 20 years.


National Institute of Standards and Technology (NIST)
Physical Measurement Laboratory (PML)
Time and Frequency Division (for additional information on time services and standards)

Note: This page can be accessed using
May 1995. Notice of Online Archive: This page is no longer being updated and remains online for informational and historical purposes only. The information is accurate as of 2004. For questions about page contents, please pml-webmaster [at] (subject: A%20Walk%20Through%20Time) (contact us).

Created July 14, 2009, Updated June 25, 2019