Britain’s power came from its navy. British merchantmen and marines sailed the world over, establishing colonies on almost every continent in both hemispheres. To keep themselves coordinated and oriented, they began to use common navigational standards, such as referencing the Greenwich Meridian to calculate their longitude. The Greenwich Meridian eventually led to Greenwich Mean Time,  for a while the world standard for timekeeping.

On this day, February 5, in 1924 the Greenwich observatory first broadcast its time signal, the five “pips” in the last five seconds preceding every hour. They continue to this day on BBC radio broadcasts, although now more as a matter of tradition, as Coordinated Universal Time (UTC), based on atomic clocks, has succeeded it in accuracy.

The pips were originally the brainchild of astronomer Frank Watson Dyson, and the head of the BBC at the time, John Reith. Dyson came up with the idea of broadcasting the pips for coordination (even going so far as adding a sixth pip for the occasional leap second), while Reith first connected them to BBC radio broadcasts.