Worldwide Evolution of Visual Time Signals After 1880

This chapter gives an overview of the numbers and types of signal that were described in Admiralty lists between 1880 and 1947. They show when time signals were introduced or changed over a long period. The introduction of wireless time signals eventually made visual signals redundant but it was a gradual change. The number of visual signals peaked in the period after the First World War and declined markedly after the Second World War. Electric time lights first appeared as principal signals in about 1909 and replaced or complemented many time balls. Time guns were operated widely, many in parallel with time balls. In 1880, the Admiralty recognised 82 visual signals: 53 time balls, 10 time guns and 19 other signals. In 1922, there were 220 listed signals: 129 time balls, 45 time guns, 21 time lights and 25 other signals. The distributions of signal types within and outside Europe are presented.