Books by Guedj, Denis

Guedj, Denis. Le mètre du monde. Paris: Seuil, 2000. ISBN 2-02-049989-4.

When thinking about management lessons one can learn from the French Revolution, I sometimes wonder if Louis XVI, sometime in the interval between when the Revolution lost its mind and he lost his head, ever thought, “Memo to file: when running a country seething with discontent, it's a really poor idea to invite people to compile lists of things they detest about the current regime.” Yet, that's exactly what he did in 1788, soliciting cahiers de doléances (literally, “notebooks of complaints”) to be presented to the Estates-General when it met in May of 1789. There were many, many things about which to complain in the latter years of the Ancien Régime, but one which appeared on almost every one of the lists was the lack of uniformity in weights and measures. Not only was there a bewildering multitude of different measures in use (around 2000 in France alone), but the value of measures with the same name differed from one region to another, a legacy of feudal days when one of the rights of the lord was to define the weights and measures in his fiefdom. How far is “three leagues down the road?” Well, that depends on what you mean by “league”, which was almost 40% longer in Provence than in Paris. The most common unit of weight, the “livre”, had more than two hundred different definitions across the country. And if that weren't bad enough, unscrupulous merchants and tax collectors would exploit the differences and lack of standards to cheat those bewildered by the complexity.

Revolutions, and the French Revolution in particular, have a way of going far beyond the intentions of those who launch them. The multitudes who pleaded for uniformity in weights and measures almost unanimously intended, and would have been entirely satisfied with, a standardisation of the values of the commonly used measures of length, weight, volume, and area. But perpetuating these relics of tyranny was an affront to the revolutionary spirit of remaking the world, and faced with a series of successive decisions, the revolutionary assembly chose the most ambitious and least grounded in the past on each occasion: to entirely replace all measures in use with entirely new ones, to use identical measures for every purpose (traditional measures used different units depending upon what was being measured), to abandon historical subdivisions of units in favour of a purely decimal system, and to ground all of the units in quantities based in nature and capable of being determined by anybody at any time, given only the definition.

Thus was the metric system born, and seldom have so many eminent figures been involved in what many might consider an arcane sideshow to revolution: Concordet, Coulomb, Lavoisier, Laplace, Talleyrand, Bailly, Delambre, Cassini, Legendre, Lagrange, and more. The fundamental unit, the metre, was defined in terms of the Earth's meridian, and since earlier measures failed to meet the standard of revolutionary perfection, a project was launched to measure the meridian through the Paris Observatory from Dunkirk to Barcelona. Imagine trying to make a precision measurement over such a distance as revolution, terror, hyper-inflation, counter-revolution, and war between France and Spain raged all around the savants and their surveying instruments. So long and fraught with misadventures was the process of creating the metric system that while the original decree ordering its development was signed by Louis XVI, it was officially adopted only a few months before Napoleon took power in 1799. Yet despite all of these difficulties and misadventures, the final measure of the meridian accepted in 1799 differed from the best modern measurements by only about ten metres over a baseline of more than 1000 kilometres.

This book tells the story of the metric system and the measurement of the meridian upon which it was based, against the background of revolutionary France. The author pulls no punches in discussing technical detail—again and again, just when you expect he's going to gloss over something, you turn the page or read a footnote and there it is. Writing for a largely French audience, the author may assume the reader better acquainted with the chronology, people, and events of the Revolution than readers hailing from other lands are likely to be; the chronology at the end of the book is an excellent resource when you forget what happened when. There is no index. This seems to be one of those odd cultural things; I've found French books whose counterparts published in English would almost certainly be indexed to frequently lack this valuable attribute—I have no idea why this is the case.

One of the many fascinating factoids I gleaned from this book is that the country with the longest continuous use of the metric system is not France! Napoleon replaced the metric system with the mesures usuelles in 1812, redefining the traditional measures in terms of metric base units. The metric system was not reestablished in France until 1840, by which time Belgium, Holland, and Luxembourg had already adopted it.

April 2007