With legal time, the clocks of one country could differ in hours, minutes and seconds from the clocks of another country. The development of international connections made this diversity impractical. So we saw the scientists, then the diplomats tried to find and then adopt a better system. In 1883, following conferences in Rome and Washington, the principle of a common meridian was adopted: that of Greenwich. It was an important, capital progress, which was going to provoke the birth of a universal regulation.

Today, in fact, the globe is conventionally divided into twenty-four time zones (comparable to the quarters of an orange) of 15 ° or an hour in extent.
The so-called initial zone is the one located at 7 ° 30 ‘on either side of the Greenwich meridian. In each of these time zones,

the average Greenwich Mean time increased or decreased as the case of a whole number of hours is taken as the single hour. Thus, watch / clocks rafiqsonsonline.com/product-category/tissot/ from around the world assumed to be exactly set mark the same minute and the same second at the same time and differ only by a whole number of hours.

Each country adopts the legal time of one of the time zones.

This convention is known as the universal time zone system. The vast majority of states have adopted it. The countries which are not very long in longitude are generally attached in full to the time zone which includes most of their territory; very large countries are attached to several time zones, generally by provinces.

The time zones are generally numbered from 0 to 23, starting from that of Cree Greenwich going east. The convention has been applied by the States which adopted it in 1912; at sea, it was adopted only in 1917.

Before the year 1917, ships at sea set their watch to the true time of the point which was made every day at noon. With this system, when two buildings met, their watches marked different hours, minutes and seconds: those of the two places where, respectively, they were the day or the day before noon.