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The Measure of the World

Denis Guedj
University Of Chicago Press
Publication Date: 
Number of Pages: 
[Reviewed by
Steven Morics
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The novel, The Measure of the World tells the true story of Pierre Méchain and Jean-Baptiste Delambre, an astronomer and a mathematician charged with measuring the meridian through Paris to create a reference for defining the meter. Their task unexpectedly took six years, coinciding with the French Revolution. For those who aren't already familiar with this episode in the history of science, here are some suggestions to get the most out of this book.

First, read the appendices. The narrative assumes that you have knowledge of surveying techniques and late 18th century French history. If you're like me, you have neither, in which case your only hope is to read the appendices on triangulation and the repeating circle and to examine the chronology and the maps. Without the mathematical background, the reader doesn't get a sense of the difficulties involved with creating this measurement, nor why the entire meridian through France needed to be measured. The book was written for a French audience, so without some familiarity with France in the 1790s, the dramatic name-dropping in the text will go right over your head.

Next, read the preface. Denis Guedj was motivated to tell this story after coming across one sentence describing the event in bare-bones terms in a book on meteorology. He goes on to tell the story of his obsession with the events; his search for original documents, the intertwining of the history of science with that of the Revolution, his travels across France, and his developing admiration for the two scientists. He was even led to recreate the measuring of the meridian. The reader gets a sense from the preface of the scope of the story and of the heroic efforts and sacrifices made by Méchain and Delambre. The stage is set for an historic epic.

Finally, decide whether to read this book or wait for another one. Unfortunately, the novel does a far less captivating job of telling the story than the preface does of building anticipation. The narrative is very uneven. The voices seem different from page to page, as though different people were writing at different times. Some events get a short treatment, while other scenes are described in laborious detail. At times, the reader is addressed directly, in the present tense, and at others, the story is told in the third pereson in the past tense. One initially suspects the problem is the translation. The Measure of the World was originally published in French in 1987, whereas the English translation didn't appear until 2001. However, the preface reveals that the text was originally written as a screenplay, and the different voices reveal that heritage. The present tense sections read like stage directions.

But, even as a screenplay, this text has problems. In successful fictionalizations of historical events (Amadeus comes to mind) the writer is able to give us a deeper insight into the characters than the historical record permits. In particular, Guedj has the opportunity to explore the motivations for starting the measurement in the first place, and for Méchain and Delambre to stick to their efforts so doggedly. Regarding the latter, the only impression we get is that they were just being good, single-minded scientists. They must complete their mission because it is science, despite the Revolution ebbing and flowing all around them. Any passion the scientists might have felt at being part of the grand scheme of improving the lot of humanity is well hidden. As to the former, there were all sorts of philosophical theories floating about, involving both mathematics and political theory, which provided fuel for the Revolution itself as well as the drive for perfection in the creation of the meter. There are myriad opportunities for grand speeches extolling those theories, with scenes of our heros getting swept up in the fervor of equality and universality. Instead, outside of a mention that those theories existed, Guedj contents himself with a few quotes from Condorcet. Indeed, the romantic Revolution Guedj mentions in his preface makes few appearances in the story.

The task was divided between the two, one of them taking the southern half of the meridian, the other taking the northern half (although it didn't turn out to be that simple), and each had an assistant. If we don't understand the motivations of Méchain and Delambre, we certainly don't understand that of the assistants, although one of them does grow beyond a cardboard cutout near the end. However, the rest of the supporting cast, including Condorcet, Borda, Laplace, Talleyrand, and Napoleon, making a surprise appearance as a mathematician, is solid, although, again, some familiarity with them is assumed.

Also assumed, or ignored, by Guedj, is the mathematics involved in measuring a meridian in the 1790s. While the measurement of the baseline is dealt with in fine detail, the triangulation leading up to it is all but ignored. The summary in the appendices belongs in the text. The mechanics of the repeating circle, a technological advance in angle measurement invented by Borda, are also left to an appendix, and even there, they're summarized in a simple manner. Without the understanding of the techniques required to accomplish the measurement, we don't get much sense of the necessity of all the climbing, lugging, and scaffold-building that occurs. And missing still from the text, but obscurely tucked away in an appendix, is a sense of the distance between observation points.

It is unclear how much of the novel is fictionalized and how much is historically accurate. If even half of what happened to Méchain and Delambre is true, this need not have been fictionalized. But in any case, novelizations of movies are invariably longer than the screenplays, and in that respect, this novel falls short. Many of the scenes have incomplete descriptions or are just too abbreviated. Guedj may have planned on letting the visuals of the movie pick up the slack, but in a novel, that luxury is no longer available. Too much detail is left to the reader to fill in, and for someone wishing an historically accurate picture of the events, that's a tall order.

Guedj is correct: there's a great movie to made regarding this story. But this is not the screenplay for that movie, or the novelization based on it.

Steven Morics ( is an Associate Professor of Mathematics at the University of Redlands in Redlands, CA. His interests in mathematics and politics are in overdrive as the voters of California decides whether or not to abide by the results of the last election.

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