The Metre of the French Revolution and the Marble Standards Surviving in Paris

One of the innovations of the French Revolution that almost all of humanity uses every day is the metre. It was a truly revolutionary decision to introduce a unified unit of length at a time when France alone had tens of thousands of different ones, and it was soon adopted in other countries too, for reasons of economic, practical and military advantage. The metre was defined as one ten-millionth of the length of the Paris meridian arc, and in time its length was refined by reference to the speed of light. So that ordinary Frenchmen might understand it, marble blocks bearing the standard were set up all over Paris, explaining exactly what a metre was. Some 20 such plaques were installed; today 2 remain in Paris and 2 in the suburbs. One of the standards is fixed on Place Vendôme, on the façade of the Ministry of Justice; the other, on Rue de Vaugirard, is the only one to have kept its original position.

Russia used its own units of measurement until the end of the 19th century.