Ten real water clocks and clepsydras: museum vessels, water-allocation bowls, Chinese reconstructions, and modern transparent-tube clocks. Photograph credits: 1. File:Yuan Bronze Water Clock.jpg; Gary Todd; CC0; https://creativecommons.org/publicdomain/zero/1.0/; https://commons.wikimedia.org/wiki/File:Yuan_Bronze_Water_Clock.jpg; 2. File:SuSongClock1.JPG; Kowloonese / Wikimedia Commons; GFDL; https://www.gnu.org/copyleft/fdl.html; https://commons.wikimedia.org/wiki/File:SuSongClock1.JPG; 3. File:Beijing 2006 1-14.jpg; G41rn8; Wikimedia Commons free license; https://commons.wikimedia.org/wiki/File:Beijing_2006_1-14.jpg; https://commons.wikimedia.org/wiki/File:Beijing_2006_1-14.jpg; 4. File:Ancient water clock used in qanat of gonabad 2500 years ago.JPG; Wikimedia Commons contributor; Wikimedia Commons free license; https://commons.wikimedia.org/wiki/File:Ancient_water_clock_used_in_qanat_of_gonabad_2500_years_ago.JPG; https://commons.wikimedia.org/wiki/File:Ancient_water_clock_used_in_qanat_of_gonabad_2500_years_ago.JPG; 5. File:Water clock zibad.JPG; Wikimedia Commons contributor; Wikimedia Commons free license; https://commons.wikimedia.org/wiki/File:Water_clock_zibad.JPG; https://commons.wikimedia.org/wiki/File:Water_clock_zibad.JPG; 6. File:Maroccan Klepsydra.JPG; Wikimedia Commons contributor; Wikimedia Commons free license; https://commons.wikimedia.org/wiki/File:Maroccan_Klepsydra.JPG; https://commons.wikimedia.org/wiki/File:Maroccan_Klepsydra.JPG; 7. File:National museum in Požarevac, water clock.jpg; Wikimedia Commons contributor; Wikimedia Commons free license; https://commons.wikimedia.org/wiki/File:National_museum_in_Po%C5%BEarevac,_water_clock.jpg; https://commons.wikimedia.org/wiki/File:National_museum_in_Po%C5%BEarevac,_water_clock.jpg; 8. File:Water clock (in a museum).jpg; Wikimedia Commons contributor; Wikimedia Commons free license; https://commons.wikimedia.org/wiki/File:Water_clock_(in_a_museum).jpg; https://commons.wikimedia.org/wiki/File:Water_clock_(in_a_museum).jpg; 9. File:(1)Hornsby Water Clock.jpg; Sardaka; CC BY 3.0 / GFDL; https://creativecommons.org/licenses/by/3.0/; https://commons.wikimedia.org/wiki/File:(1)Hornsby_Water_Clock.jpg; 10. File:Time-Flow Clock.jpg; Wikimedia Commons contributor; Wikimedia Commons free license; https://commons.wikimedia.org/wiki/File:Time-Flow_Clock.jpg; https://commons.wikimedia.org/wiki/File:Time-Flow_Clock.jpg;