Consider the most fundamental of measurements: the measurement of physical distances, as when we use feet and yards, or meters. Once upon a time, a foot must have been thought of as the size of, well, a human foot, without worrying whose foot exactly. These days, we are no longer satisfied with this level of imprecision, of course, and concepts such as the foot and the meter have long been standardized—at least to an extent. Since meters are the international currency in most areas of science and engineering, let us briefly look at the history of the meter.

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