WORLD IN THE BALANCE

A look at how weights and measures evolved over the ages, and their importance as a social bond.

Physics World columnist Crease (Philosophy/Stony Brook Univ.; The Great Equations, 2009, etc.) starts with the beginning of commerce. From early times, merchants and their customers needed a set of standards that would assure both that they were getting a fair deal. Different societies arrived at different methods of attaining this goal. In China, each new dynasty needed to prove its legitimacy by “improving” its predecessors’ standards for weight, length and music. In West Africa, the use of small figurines to measure gold became the keystone of society. But as trade became more international, the great trading nations began to impose their standards on their partners. Britain and France were in many ways the leaders, the former with the Imperial system, the latter, after the Revolution, with the metric system. This battle for dominance makes up much of the narrative. The meter was a philosophical construct, based in theory on the size of the Earth—specifically, on the meridian of longitude passing through Paris. The French government sent out expeditions to measure the meridian and arrived after some trouble at a standard meter. Advocates of the new system immediately began to proselytize for it, sending copies of the standard to other nations including the United States, where the “scientific” measure had a strong advocate in Thomas Jefferson. Crease also emphasizes how human nature played a part, both in the success of the new system and in the resistance to it. Especially in America, religious conservatives railed against its adoption as early as the 1860s. Meanwhile, American scientists were among those who strove to improve its accuracy. Crease provides a solid explanation of how something so arbitrary can be made truly “universal.”

Scientific history that looks beyond the facts and figures to their influence on everyday life.