In Measure of the Earth, Larrie Ferreiro recounts the fascinating tale of an equatorial expedition to determine the shape of the planet
IN 1671, France sent astronomer Jean Richer to South America to map the skies of the southern hemisphere. Richer, whose work helped the French navy navigate the world, took with him two pendulum clocks. Though they had been carefully calibrated in Paris, he was dismayed to find that they lost 2 minutes 28 seconds per day in French Guyana compared with local clocks.
Upon his return home in 1673, this discrepancy caused an international scientific uproar. Isaac Newton…
