This became a problem in the mid 19th century when railways needed clocks that were synchronized between stations, at the same time as people needed to match their clock (or the church clock) to the time tables.
これは19世紀半ばに、鉄道が各駅で同期された時刻を必要とし、また人々が時計（または教会時計）を時刻表に合わせる必要が出てから問題になった。