Thursday, April 19, 2007

Semi-non-archaeological book review The Measure of All Things: The Seven-Year Odyssey and Hidden Error that Transformed the World by Ken Alder. Publisher's Weekly summary:
Alder delivers a triple whammy with this elegant history of technology, acute cultural chronicle and riveting intellectual adventure built around Delambre's and Mechain'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 Mechain made a mistake in his calculations, which he covered up, and which tortured him until his death. Mechain, 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 Mechain 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 regime 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.
Copyright 2002 Reed Business Information, Inc.

That's a good summary. The ultmate goal of the book is really an explication of the origin of our modern ideas about measurement error. It's really a perfect setup though: and attempt to obtain precise and accurate measurments to make a precise and accurate device to measure by.

The first half may lose some readers as the ultimate point of all their measurements is not inherently clear; although Mechain and Delambre's adventures in immediately post-revolutionary France are certainly interesting in and of themselves, it can be tedious going. On the other hand, I for one would have liked some more detail on how exactly they were carrying out these measurements, how the circles really worked, etc. Although that would have lost even more general readers, surely. It's important to read the section on the error itself closely or you will miss it and its significance.

It's a good introduction as to how the metrc system came about and how it was initially adopted. The ultimate goal was to have based the meter on an actual physical object, in this case the size of the Earth. On one hand, it wasn't really essential that the meter be based on anything in particular, just that the standard and copies of it were created with precision and accuracy. After all, any standard measure will do, in theory. On the other hand, their pursuit was perfection in the ideal -- sort of an uber-essentialst position -- and perfection in that conceptual world was rooted in Nature with a capital N.

The second half of the book really gets going and explains what the significance of their measurements were and what it meant for developing the metric system. This is when we really see what the detailed descriptions of both Delambre's and Mechain's field methods were all about. From there Alder gives a brief history of how the metric system was adopted in various countries -- or not -- and provides good context for US readers as to how it came not to be adopted here (which is similar as to why it almost didn't become adopted at all).

See here for a timeline of the meter.

So, I'd recommend it. A good read if you can make it through the first half.