Image: Christiaan Huygens Clock and Horologii Oscillatorii

Description: One of the first pendulum clocks designed by the inventor of the pendulum clock, French scientist Christiaan Huygens, and his treatise on the pendulum, Horologii Oscillatorii published in 1673, on display in Museum Boerhaave in Leiden, Netherlands. This may be Huygens second pendulum clock, which was also finished in 1673 and is shown on the open page of the book. In it Huygens attempted to make the swing of the pendulum isochronous using "cycloidal cheeks" of metal (shown on page) to confine the suspension cord and give the pendulum a cycloidal trajectory. Huygens claimed an accuracy of 10 seconds per day.
Title: Christiaan Huygens Clock and Horologii Oscillatorii
Credit: http://www.flickr.com/photos/koopmanrob/3775343287/sizes/o/
Author: Rob Koopman (Flickr profile)
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