The Metre Convention of 20 May 1875 is a treaty which established three international organizations to oversee the keeping of metric standards. It is written in French, in which it is called the Convention du Mètre. In English it is also called the Treaty of the Meter. It was revised in 1921. In 1960, the system of units it established was renamed the "International System of Units" (Système international d’unités or SI).
The Convention created three main organizations:
General Conference on Weights and Measures (Conférence générale des poids et mesures or CGPM) – a meeting every four to six years of delegates from all member states;
International Bureau of Weights and Measures (Bureau international des poids et mesures or BIPM) – an international metrology centre at Sèvres in France; and International Committee for Weights and Measures (Comité international des poids et mesures or CIPM) – an administrative committee which meets annually at the BIPM.
The metric system was conceived by a group of scientists (among them, Antoine-Laurent Lavoisier, who is known as the "father of modern chemistry") who had been commissioned by Louis XVI of France to create a unified and rational system of measures. After the French Revolution, the system was adopted by the new government. On August 1, 1793, the National Convention adopted the new decimal "metre" with a provisional length as well as the other decimal units with preliminary definitions and terms. On April 7, 1795 (Loi du 18 germinal, an III) the terms "gramme" and "kilogramme" replaced the former terms "gravet" (correctly "milligrave") and "grave". On December 10, 1799 (a month after Napoleon’s coup d’état), the metric system was definitively adopted in France.
The history of the metric system has seen a number of variations, whose use has spread around the world, to replace many traditional measurement systems. At the end of World War II a number of different systems of measurement were still in use throughout the world. Some of these systems were metric-system variations, whereas others were based on customary systems. It was recognised that additional steps were needed to promote a worldwide measurement system. As a result the 9th General Conference on Weights and Measures (CGPM), in 1948, asked the International Committee for Weights and Measures (CIPM) to conduct an international study of the measurement needs of the scientific, technical, and educational communities. Based on the findings of this study, the 10th CGPM in 1954 decided that an international system should be derived from six base units to provide for the measurement of temperature and optical radiation in addition to mechanical and electromagnetic quantities.
The failure of a recent space flight costing $millions was directly due to data in metric measurement being interpreted as local US units! A recent example of The six base units that were recommended are the metre, kilogram, second, ampere, degree Kelvin (later renamed the kelvin), and the candela. In 1960, the 11th CGPM named the system the International System of Units, abbreviated SI from the French name: Le Système international d’unités. The seventh base unit, the mole, was added in 1971 by the 14th CGPM. There were originally 17 signatories to the treaty. This number grew to 52 in 2008. The near-worldwide adoption of the metric system as a tool of economy and everyday commerce was based to some extent on the lack of customary systems in many countries to adequately describe some concepts, or as a result of an attempt to standardise the many regional variations in the customary system. International factors also affected the adoption of the metric system, as many countries increased their trade.Liquids, especially alcoholic ones, are often sold in units whose origins are historical (for example, pints for beer and cider in glasses in the UK — although pint means 568 ml; champagne in Jeroboams in France). In Britain imperial measurements are permitted indefinitely alongside the metric system as supplementary indications.