• A Brief History of Clocks: From Thales to Ptolemy
  An essay on premechanical clocks by Jesse Weissman.
• A Walk Through Time
  A delightful overview from NIST.
• Clepsydrae Water clocks from Rees's 1819 Clocks, Watches and Chronometers
• Heroes of Horology A Gallery of Portraits compiled by Robert Terwilliger
• "On the Disturbances of Pendulums and Balances, and on the Theory of Escapements." by Sir George Biddell Airy
  Airy's classic 1826 article on the theory of pendulum timing.

Adobe PDF Files

Get Adobe Acrobat Reader (Version 4.0 or greater recommended to view or print the following files).

• "On the effect of the Internal Friction of Fluids on the Motion of Pendulums" by Sir George Stokes [PDF file, 973 KB]
  Analysis of the effect of air on pendulums by a pioneer in hydrodynamics. Heavily mathematical.
• "Spring Suspensions for a Pendulum" by R. M. Fedchenko and A. G. Fleer, 1966, translated. [PDF file, 174 KB]
  Analysis of Fedchenko's constant-period (isochronous) clock escapement.
• "The Pendulum--Rich physics from a simple system" by Robert A. Nelson and M. G. Olsson [PDF file, 274 KB]
  Most detailed analysis we are aware of of factors affecting the period of a pendulum.
• "The Value of Gravity at Washington" by Paul R. Heyl and Guy S. Cook [PDF file, 668 KB]
  Use of silica pendulums suspended on knife-edges to determine gravity.

UBR, Inc. Page last revised 21.1 Mar 2006. <clocks/hist/hist.html>