Discovered a fascinating job in late 19th century London: train timekeepers. Stations in cities across England wanted to keep track of London time, aka railway time. Railway workers would set their watches, ride the train, get off at each stop, and show their watch to the station master, who would set a clock marked "London time."
Clocks were imperfect and inevitably skewed, so the timekeepers did this regularly to fix them.
This is basically NTP, the venerable protocol for synchronizing clocks between computers connected over a network. The timekeepers even correspond to the UDP packets that NTP uses to communicate the current time over the network. Love it.