# Where does the metric system come from?

## metric system

metric system, in the broader sense any system of units whose base units are the meter (or a multiple thereof), the gram (or a multiple thereof) and the second and which has a decimal division of the units, in the narrower sense specifically the system of units that was introduced in 1875 with the International Meter convention introduced in 17 countries, later expanded to the MKSA system and meanwhile transferred to the international system of units (SI system).

The approach of the metric system goes back to the 17th century. back: In 1661 the English astronomer and architect Christopher Wren suggested the length of a half-second pendulum as a natural measure for the unit of length, similar to 1664/73 the Dutch naturalist Christiaan Huygens. The French astronomer Gabriel Mouton proposed in 1670 to use the arc minute of a meridian degree as a natural measure of the unit of length and to divide it into decimal. By 1790, politicians in Great Britain, the United States, and France took up these and other scientific proposals; The French advances were the most momentous: the Académie des Sciences was commissioned to begin creating a new system of units based on a suitable physical quantity, thus giving all nations the opportunity to adopt the new units. In 1791 the Académie recommended calculating the unit of length from measurements of a meridian quadrant. The measurements of the meridian arc between Dunkirk and Barcelona began in 1792, and on April 7, 1795 the National Convention carried out the so-called metric system in France a. A line measure made of platinum (›mètre provisoire‹) as early as 1793 should do that meter (from Greek ›métron‹ measure) as the ten millionth part of the earth's meridian quadrant. Other units were the Ar (10 m2) for the area, the stère (1 m3) as a spatial measure for layered firewood, the liter (1 dm3) for the volume of liquids and solids as well as the gram as the mass of 1 cm3 pure water at the temperature of the ice point. (The second as the 86,400th part of a day was not part of the regulation.) Furthermore, the unit prefixes kilo, hecto, deca, deci, centi and milli, which are still in use today, were set.

Under the Bourbons, the metric system was banned in 1816 and only re-enacted in France in 1837 with effect from January 1, 1840. In Germany, the metric system was introduced by the order of measures and weights of 1868 for the North German Confederation and on January 1, 1872 for the German Empire. The regulations have been revised several times; currently the law on units in metrology of 1969 applies (metrology, international meter convention, length, meters, kilograms)