Origin of time zones and world clock

Originally, each village had its own called local time, which was determined by the sun: when the sun reached its highest point above the horizon, it was 12 noon clock. Travelers were directed to the local time of the place reached in each case. With the emergence of the railroad time standard was necessary, which was considered in the broader field of railway, for example, to be able to write general schedules. Thus, the time of a major city, often one of the termini of the railway line to the nationally accepted standard time. That was partly the time of the capital. Examples: Berlin, Hamburg, Munich, Prague, Berne and Geneva time. Was not satisfactory, the situation in cities in which ended several railroads. Geneva was the terminus for one of Paris and for a coming from Bern railway line and had the time in Paris and Berne time in addition to their time in Geneva.


 In east-west or west-east travel on board a ship, the time change is handled quite arbitrary and the days on which a change is determined according to the operational requirements on board. Usually more than one hour will be changed in a day. The day that happens, does not necessarily have to coincide with the crossing of the geographical border between two time zones. The hour is usually placed in three 20-minute intervals during the night: The first 20 minutes during the 20-24-clock guard, the second 20 minutes during the 0-4 clock-and-watch the last 20 minutes during the 4-8-clock guard. This ensures that the change caused by the more-or less work is distributed evenly across all three guards. For two guard vessels are treated analogously and adjusted twice in 30 minutes.

An improvement was created by the first half of the 19th Century introduced telegraphy. In the 1840-1860s in almost all European countries a uniform standard time was fixed, which could make the country known by telegraph signals emitted time. They chose the most time of their capital.
The subsequent systematic time zones were first introduced not by states but by North American railroads 1883rd Transversely guided on the continent Railroads accounted for more than a standard time required. The areas were divided into four (later five) time zones. U.S. and Canada were able to take this time zones later with minor correction in their state regulations, because they differed from the Greenwich Mean Time (UTC later) at all hours.
The systematic global time zone system was a result of the international agreement of the Greenwich meridian as zero meridian at the Washington International Meridian Conference 1884th Which is important for the mapping Nullmeridian henceforth served as reference meridian for the subdivision of the earth in time zones.