The Measure of All Things

PUBLISHERS WEEKLY JUL 1, 2002

Alder delivers a triple whammy with this elegant history of technology, acute cultural chronicle and riveting intellectual adventure built around Delambre's and M chain's famed meridian expedition of 1792 1799 to calculate the length of the meter. Disclosing for the first time details from the astronomers' personal correspondences (and supplementing his research with a bicycle tour of their route), Alder reveals how the exacting M chain made a mistake in his calculations, which he covered up, and which tortured him until his death. M chain, remarkably scrupulous even in his doctoring of the data, was driven in part by his conviction that the quest for precision and a universal measure would disclose the ordered world of 18th-century natural philosophy, not the eccentric, misshapen world the numbers suggested. Indeed, Alder has placed Delambre and M chain squarely in the larger context of the Enlightenment's quest for perfection in nature and its startling discovery of a world "too irregular to serve as its own measure." Particularly fascinating is his treatment of the politics of 18th-century measurement, notably the challenge the savants of the period faced in imposing a standard of weights and measures in the complicated post ancien r gime climate. Alder convincingly argues that science and self-knowledge are matters of inference, and by extension prone to error. Delambre, a Skeptical Stoic, was the more pragmatic and, perhaps, the more modern of the two astronomers, settling as he did for honesty in error where precision was out of reach.