The Measure of All Things

Ken Alder

Read October 2003

This is an excellent history. Alder describes the process by which the French first defined the length of the meter. This story might be interesting enough on its own, but it is wrapped up significantly in an epochal event: the French revolution. The Revolution begins as a backdrop, but proceeds to play an increasingly important role in the execution and then even in the definition of the measurement: how the absence of standard measures had been among the complaints to the king, how the meter played to the Revolutionary zeal for universals, how it came to be seen as a pawn for French domination, and so on.

Alder chooses to peg the book to a hidden error, which is a questionable decision. It does let him present the story as something of a thriller. But the savvy modern reader will probably see through the ploy, and therefore find the story's narration a touch tiresome. There's plenty enough in this book to keep this from becoming significant, but it is occasionally wearing.

Beyond the story of the meter, Alder draws us into the Revolution and the lives of the savants of the day. We pan across France's remarkable scientific community of the era. A modern reader can only read with sadness of a time that pitted the like of Carnot against Laplace and Lavoisier. And Alder, himself a professor, exposes numerous unstated (and often cynical) parallels to the fund-raising techniques of scientists across the ages. An interesting sideshow is America's flirtation with, but eventual rejection of, the metric system.

One of the book's strengths is its discussion of error in science and the rise of statistical methods. This must be valuable to a lay reader; if anything, the book doesn't cover this topic enough (though it isn't strictly on topic). The author does, however, jump to the rather poorly justified, and surprising, conclusion that Delambre, the key figure in the measurement, was sensitive to its errors all along. None of his earlier behavior justifies such a conjecture. The more significant problem with the book is the lack of sufficient description of the process of measurement itself. What is measure, how does one compare measures, and in what terms did the savants describe their results, anyway? Some of these questions are covered better than others, and some answers are hidden in the prose, but a basic description of both trigonometry and of the notion of measure would have been a valuable addition.

Despite these minor blemishes, this is an enjoyable and worthy book. The author deftly intertwines human and scientific processes. He midly chides the naivete of the more idealistic scientists while still giving their work its full measure of honor. And the true protagonist of the book is, in the end, distance itself: as he says (p. 138), "Making measurement banal proved to be hard work and would take more than century of struggle and conflict".