Time signal

A time signal is a visible, audible, mechanical, or electronic signal used as a reference to determine the time of day.

Audible and visible time signals

One sort of public time signal is, of course, a striking clock. These clocks, however, are only as good as the clockwork that activates them; they have improved substantially since the first surviving clocks from the fourteenth century. For many members of the general public, a public clock such as Big Ben was the only time standard they needed.

Related Topics:
Striking clock - Fourteenth century - Big Ben

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When more accurate public time signals were desired for use in navigation, a number of traditional audible or visible time signals were established for the purpose of allowing navigators to set their chronometers by. These public time signals were formerly established in may seaport cities.

Related Topics:
Navigation - Chronometer - Seaport

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As an example of such a signal, in Vancouver, British Columbia, a "9 o'clock gun" is still shot every night at 9 PM. This gun was brought to Stanley Park by the Department of Fisheries in 1894 to warn fishermen of the 6:00 PM Sunday closing of fishing. The 9:00 PM firing was later established as a time signal for the general population. The Brockton Point lighthouse keeper, William D. Jones, originally detonated a stick of dynamite until the Time Gun was installed. A similar "noon gun" was formerly shot every noon at Cape Town, South Africa. A cannon was shot at one o'clock every weekday at Liverpool, England, at the Castle in Edinburgh, Scotland, and also at Perth in Australia to establish the time. A cannon located at the top of Santa Lucia Hill, in Santiago, Chile, is shot every noon.

Related Topics:
Vancouver - British Columbia - Stanley Park - Department of Fisheries - 1894 - Fishermen - Sunday - Brockton Point - Cape Town - South Africa - Liverpool - England - Castle - Edinburgh - Scotland - Perth - Australia

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The ceremony of "dropping the ball" at New Year's Eve in Times Square in New York City is a vestige of a visual indication of time. The first such time ball was installed in 1833 on the roof of the Royal Observatory in Greenwich, England. The ball was set to drop at 1 P.M. to enable the astronomers to establish the correct moment it should drop by observing the sun at noon. Liverpool, Edinburgh, and Perth also had balls that were dropped concurrently with the firing of the time cannons. Because the speed of light is much faster than the speed of sound, visible signals enabled greater precision than audible ones; however, the audible signals could operate under conditions of reduced visibility. In 1861 and 1862, the Post Office Directory had time gun maps published that related the number of seconds it took for the report of the time gun to reach various locations in Edinburgh.

Related Topics:
New Year's Eve - Times Square - New York City - Time ball - 1833 - Royal Observatory - Greenwich - Astronomers - Speed of light - Speed of sound - 1861 - 1862 - Post Office Directory - Map

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In many non-seafaring communities, loud factory whistles served as public time signals before radio made them obsolete.

Related Topics:
Factory - Whistle - Radio

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