Metre Convention

Metre Convention (French: Convention du Mètre, also known as the Treaty of the Metre) is an international treaty, signed in Paris on 20 May 1875 by representatives of seventeen nations which set up an institute for the purpose of coordinating international metrology and for coordinating the development of the metric system. The treaty also set up associated organisations to oversee the running of the institute. Initially it was only concerned with the units of mass and length, but in 1921, at the 6th meeting of the General Conference on Weights and Measures (CGPM), it was revised and its mandate extended to cover all physical measurements. In 1960, at the 11th meetings of the CGPM, the system of units it had established was overhauled and relaunched as the "International System of Units" (SI).

The Convention created three main organizations:

• The 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.
• The International Committee for Weights and Measures (Comité international des poids et mesures or CIPM) – an advisory body to the CGPM consisting of eighteen prominent metrologists from eighteen different countries.
• The International Bureau of Weights and Measures (Bureau international des poids et mesures or BIPM) – an organisation based at Sèvres, France that has custody of the International Prototype Kilogram, provides metrology services for the GCPM and CIPM, houses the secretariat for these organisations and hosts their formal meetings.

Membership of the convention is restricted to countries who have diplomatic relations with France, but in 1999 the category of associate membership was introduced for those nations that wished to partake in the [calibration and measurement Mutual Recognition Agreement (MRA) program without taking part in the activities of the BIPM.