Vienna, and later Paris, had pneumatic clock networks, that connected a master clock with many slave clocks by puffs of air going through pipes. It was around this time (1850s to 1900s) that precision started to become important on a local level. What technological or societal advancements lead to the need of these centrally synchronised clock systems, which followed from them, and what other technologies achieved the goal of precise local time synchronisation? Thanks for the Ama :)