Metre Convention
The metric system was developed in France in the 1790s. The length of the metre was made to be one ten millionth of the distance between the North Pole and the equator. Between 1791 and 1798 the French men Delambre (a mathematician and astronomer) and Méchain (an astronomer) measured the distance between Dunkirk and Barcelona. The measurements were used to make a metal bar exactly 443.296 lignes long (the ligne is an old French unit of length equal to one twelfth of a French inch). The bar would be used as a standard for the metre. The bar was later called the metre des archives. By the 1860s it was found that the metre des archives was 0.03% shorter than it was supposed to have been.