The Steampunk Clocks of 19th-Century Paris: Discover the Ingenious System That Revolutionized Timekeeping in the 1880s
Briefly

The idea was to have a master clock in the center of Paris that would send out a pulse each minute to synchronize every clock around the city,
The clocks wouldn't have to be powered, the bursts of air would simply move all the clocks in the system forward at the same time.
Read at Open Culture
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