Meet me at the Coffee Connection on Dempster, author and Northwestern University history professor Ken Alder had said. So ten minutes before the appointed hour, after speed-reading his 400-page book The Measure of All Things: The Seven-Year Odyssey and Hidden Error That Transformed the World in an airline seat with a burned-out light, I am cruising Evanston. The Coffee Connection turns out to be as elusive as the subject of Alder’s book. After a call to his home and some quick empirical research (he’s not at Blind Faith, not at Starbucks), I blunder into Cafe Express and find him ensconced at a corner table. Error, as modern science knows, is our constant companion.

In the 18th century, error was an abomination. The heroes of Alder’s book, two French astronomers charged with measuring a 600-mile slice of the meridian–an errand they believed to be the most important scientific mission ever attempted–were seeking perfection. While the French Revolution raged around them, Jean-Baptiste-Joseph Delambre and Pierre-Francois-Andre Mechain set out from Paris, one to the north, the other to the south, to measure the distance from Dunkerque to Barcelona. The data they brought back would be used to establish a new unit of measure worthy of global use. In 1792, when their odyssey began, units of measurement and the values given to them varied, not only from one country to another but between villages and industries. A pound of bread in one town might differ in weight both from a pound of bread in another town and from a pound of iron. With such disparity, trade on anything larger than a local scale was nearly impossible. What was needed was a system of measurement based not on neighborhood tradition (or the size of a king’s foot) but on ubiquitous and eternal nature. The meter would be exactly one ten-millionth of the distance from the north pole to the equator.

Delambre and Mechain spent seven years measuring and calculating, using a series of connected imaginary triangles. In 1799, based mostly on their data, an absolute standard was struck in the form of a platinum bar, which was deposited in a triple-locked box in the French National Archives. By the middle of the next century, however, it was clear that something had gone wrong. Scientists had discovered that the “perfect” meter, the unit of measure in worldwide use today, is two-tenths of a millimeter shorter than it should be.

Alder, the son of a physicist, was once a science student himself–a Harvard physics major who jumped to the history department for graduate school and cranked out a novel while he was there (The White Bus, a semiautobiographical coming-of-age story published in 1987). He’s the author of Engineering the Revolution, a prizewinning history of the gun, published by Princeton University Press in 1997 and also set in Revolutionary France. The period draws him, he says, because people then “really thought you could start the world anew and were calling on science to help design it.” As a novelist, he’s also drawn to “the theme of somebody who feels they’ve made a terrible mistake.” He began work a decade ago on a novel about a scientist “who wants to undo what he’s done”; he set it aside to write this story, “about a man who felt he was bearing the burden of Atlas on his shoulders and thought he had messed up.” As Alder found during his own seven-year odyssey of research and writing (which included bicycling the 600-mile route from Dunkerque to Barcelona), Mechain had kept a scandalously sloppy log (penciled notes on loose pages), massaged his data, and dumped a set of measurements that suggested he’d made an error. Obsessed by his apparent failing, he became depressed and paranoid, stopped working, hid out, and finally had to be forced to return to Paris where, under pressure, he presented doctored results. It wasn’t until after he died in 1804, during a misguided attempt to correct the erroneous measurements, that Delambre acquired his papers, learned his secret, and realized that their meter, by then the official measure of France, was flawed. Two hundred years later, in the archives of the Royal Observatory, Alder was shocked to find Delambre’s note explaining what he decided to do about that: “I have not told the public what it does not need to know,” it said.

But there was another, more fundamental error in the project. “Their basic assumption [that one meridian would be exactly the same length as another] was flawed,” Alder says. “They didn’t realize that the earth is not uniform. It’s lumpy, it’s warped, you can’t extrapolate from one portion of it to the whole.” The most important result of the search for the perfect meter was the recognition that science needed a way to deal with uncertainty or error in measurement. Alder says this led to the development of statistics and made modern science possible. In the end, it was the quixotic nature of the story that held him, he says: “the way it shows how messy and human the process that makes science is.”

The Measure of All Things has been published in England and is being translated into 11 other languages. Two weekends ago it popped up on the cover of the New York Times Book Review, where it got an appreciative thumbs-up. Now Alder’s in the middle of a 12-city tour, enduring error-prone interviews with ignorant speed-readers. In the growing din at Cafe Express I ask if he biked the whole route at once. He responds that it took a year and a half to write. And where did your father teach? “Berkeley,” he answers. “Ah,” I nod: “Brooklyn.”

Alder will read from his book Monday, October 28, at 7:30 PM at the Book Stall, 811 Elm in Winnetka. He’ll also appear Wednesday, November 6, at 7:30 PM at the Evanston Public Library, 1703 Orrington in Evanston.

Art accompanying story in printed newspaper (not available in this archive): photo/Jim Newberry.