Metre Convention

Metre Convention (French: Convention du Mètre), also known as the Treaty of the Metre, is an international treaty that was signed in Paris on 20 May 1875 by representatives of 17 nations. The treaty 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 organizations 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 international organizations:

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 aspects of the CIPM Mutual Recognition Agreement (CIPM-MRA) program without taking part in the activities of the BIPM.

In England in 1215, clause 25 of the Magna Carta set out the standards of measure that were to be applied throughout the realm prefixed. The wording of the clause emphasised that "There is to be a single measure ... throughout our realm". Five centuries later, when in 1707 England and Scotland were united into a single kingdom, the Scots agreed to use the same units of measure that were already established in England. During the eighteenth century, in order to facilitate trade, Peter the Great, Czar of Russia adopted the English system of measure.

Abuse of units of measures were one of the causes of the French Revolution and its reform was one of the items on the agenda of National Assembly. Talleyrand, an influential leader of the Assembly invited British and American participation in the establishment of a new system, but in the event, the Assembly went it alone and introduced the metre and the kilogram which were to form the basis of the metric system, manufacturing prototypes which, in 1799, were lodged with Archives.

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