Excerpt from The Measure of All Things by Ken Alder, plus links to reviews, author biography & more

The Revolutionary scientists created the metric system two hundred years ago to avoid just this sort of fiasco. One of their aims was to facilitate communication among scientists, engineers, and administrators. Their grander ambition was to transform France -- and ultimately, the whole world -- into a free market for the open exchange of goods and information. Today, their goal seems within reach. Over 95 percent of the world's population now officially uses the metric system, and its success is touted as one of the benign triumphs of globalization.

But behind the public triumph of the metric system lies a long and bitter history. The fundamental fallacy of utopianism is to assume that everyone wants to live in the same utopia. France, it turns out, was not only the first nation to invent the metric system; she was also the first to reject it. For decades after its introduction ordinary people spurned the new system, and clung to their local measures and the local economies they sustained. In the face of this revolt from below, Napoleon, on the eve of his disastrous invasion of Russia, returned France to the Paris measures of the Ancien Régime. Now he mocked the global aspirations of the men he had once admired. "It was not enough for them to make forty million people happy," he sneered, "they wanted to sign up the whole universe." Not until the middle of the nineteenth century did France revert to the metric system, and even then use of the old measures persisted into the twentieth. It would take enormous scientific effort and years of bitter conflict to make metric measurement banal, just as it had taken a Revolution to bring the metric system into being. Things might easily have turned out differently.

What neither advocates nor opponents of the metric system could have known is that a secret error lies at the heart of the metric system -- an error perpetuated in every subsequent definition of the meter. Indeed, as I discovered in the course of my research, the only people who could have known the full extent of this error were Delambre and Méchain themselves.


For those who wish to know the origins of the metric system, there is one place to turn: the official account composed by one of the leaders of the meridian expedition, the north-going astronomer, Jean-Baptiste-Joseph Delambre. Delambre wrote the Base du système métrique décimal -- which we might translate as The Foundation of the Metric System -- in order to present all the expedition's findings "without omission or reticence." At over two thousand pages, this magisterial work certainly appears thorough enough. But bulky and authoritative as it is, the Base is a strange book, with puzzling contradictions. Reading it, I began to get the sense that this was not the complete history of the meter, and that Delambre had himself scattered clues to this effect throughout the text. For instance, in Volume 3 he explained that he had deposited all the records of the metric calculations in the archives of the Observatory of Paris lest future generations doubt the soundness of their procedures.

The records are still there. The Observatory of Paris is an imposing stone structure just south of the Luxembourg Gardens in the heart of modern Paris. In the 1660s, when Louis XIV founded the Royal Observatory and Royal Academy of Sciences, his goal was to couple the glory of his rule with the new heavenly science, and also to supply his savants with the tools they would need to assemble an accurate map of his kingdom here on earth. The building is perfectly aligned along the nation's north-south meridian. Like France, it presents two faces. From the north, it might almost be mistaken for a royal fortress, with austere stone walls guarding a gray plain of mist and gravel that stretches toward the North Sea. From the south, it resembles an elegant residential palace, with octagonal pavilions looking out over a terraced park that seems to step, via an alley of plane trees, down to a remote Mediterranean. During the Ancien Régime, most of France's finest astronomers lodged within its green precincts. Today, the site remains the privileged workplace of its leading astrophysicists.

Copyright © 2002 by Ken Alder.