THE MEASURE OF ALL THINGS

A robust work of science history and literary travel, with a dose of the whodunit as a lagniappe.

Love it, hate it, or simply use it, as most of the world does, the metric system is with us to stay, and even the most resistant of Americans will likely be doing his or her ciphering in grams and centimeters some day soon. So Alder (History/Northwestern Univ.) prophesies at points in this tangled story, which traces how the metric system came to be. The meter, he writes, has a strange but honorable history, bound up in the revolutionary politics of late–18th-century France and the brilliant reformer Condorcet, who promised that this new means of measurement would be “for all people, for all time”—and that in any event it would replace the staggering array of 250,000 units of measurement used in France under the monarchy. True to the spirit of the time, the astronomers Jean-Baptiste-Joseph Delambre and Pierre-François-André Mechain set out to prove that the length of the proposed meter was accurate, calculating it by geodesic triangulation along a route that took the two of them, step by step and (beg pardon) inch by inch along the length of France. The journey was not an easy one, writes Alder, who followed it by bicycle; both Delambre and Mechain encountered considerable difficulties in the form not only of geophysical obstacles but also of overzealous revolutionaries who wanted, among other things, to blow up the steeples from which the two mapped points along the way. And somewhere a dispirited Mechain made an error in calculation, one that he attempted to conceal, as did Delambre when eventually he caught on. The implications remain with us, Alder observes, as he closes a narrative marred only by occasional repetition.

Will satisfy history-of-science buffs and intellectual historians alike.