Note 2 — Preface

Magellan’s mistake in reckoning.As Magellan, who discovered the Philippines in his memorable first circumnavigation of the globe, was following the sun in its apparent daily path around the world, every successive degree he compassed on his eastern course added four minutes to the length of his day; and, when he reached the Philippines, the difference amounted to sixteen hours. This, however, apparently escaped his notice, for Elcano, the captain of the only remaining vessel, was quite unaware, on his return to the longitude of his departure, why according to his ship’s log-book, he was a day behind the time of the port which he had reached again by continuously sailing westward.23