The Measure of All Things: The Seven-Year Odyssey and Hidden Error That Transformed the World

In June 1792, amidst the chaos of the French Revolution, two intrepid astronomers set out in opposite directions on an extraordinary journey. Starting in Paris, Jean-Baptiste-Joseph Delambre would make his way north to Dunkirk, while Pierre-François-André Méchain voyaged south to Barcelona. Their mission was to measure the world, and their findings would help define the meter as one ten-millionth of the distance between the pole and the equator—a standard that would be used “for all people,...