Le prototype international du kilogramme Un étalon réussi Histoire de son choix et de sa réalisation

摘要

The decisions and facts that led to the realisation of the International Prototype Kilogram and the contributions of numerous scientists are reviewed, The first choice had to be made between a metallic and a crystal prototype and, after the decision taken in 1870 in favour of the platinum-iridium alloy, many a difficulty in melting and casting ingots of satisfactory chemical purity and physical perfection had to be overcome.In the meantime the organisations of the international metrological structure were created by the Convention du Métre. In1883 the International Prototype Kilogram was ready and made official by CIPM, and in 1889 the first Conférence Générale des Poids et Mesures defined by it the unit of mass and assigned the first twenty national prototype kilograms to the countries adhering to the Convention du Mètre.