Science: Measure for Measure

Three stories underground, surrounded by tons of reinforced concrete, the tiny vault lay undisturbed through nine stormy years. Last week, learned representatives of 18 countries came to the Pavilion de Breteuil outside Paris, solemnly squeezed into the little vault. There, reposing in a glass case, were the objects these delegates to the first postwar convention of the International Bureau of Weights and Measures had come to see: The Kilogram and The Meter, in person—the official standards of weight and measure for the world's metric system.

The Kilogram is a spool-sized chunk of 90% platinum, 10% iridium, weighing exactly one kilogram (2.2046 Ibs.)....

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