2. Before Columbus, the Earth was “Flat”? Flat Wrong
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2 Before Columbus, the Earth Was “Flat”? Flat Wrong We shall assume that the earth is spheroidal. The evidence of the senses and common observation are alone requisite. —Strabo, Geography, AD 18–19 Most of us were told in school that it was a flash of insight by Christopher Columbus that taught humanity that the world was round, not flat. However, that notion is entirely erroneous. Any reasonably sophisticated pragmatic observer who notes that the higher one’s viewpoint, the farther one can see, or who observes a ship pass over the horizon or the land “sink” into the sea as one’s craft sails away from shore, is likely to work out that the earth’s surface is curved. This conclusion might be reinforced by observations that the visible constellations and their paths’ heights above the horizon were not the same at different places on Earth—that as one goes poleward the elevation of the noon sun decreases and that of the polestar increases—and that the apparent pathways of the stars are parallel in a coordinated fashion, a rotating terrestrial globe being one of the two possible logical explanations (the other being a celestial sphere rotating around a fixed earth—the actual Classical conception). The curved shadow of Earth upon the moon during lunar eclipses might also give a clue. In fact, the Greek philosopher Aristotle (384–322 BC) offered these phenomena as proofs of terrestrial sphericity, and he was followed not only by other Greeks and Romans (in­ clud­ ing Krates, discussed in chapter 1) but also by medieval Arab and European thinkers.1 As will appear, the ancient Chinese also had formal theories about the sphericity of the globe. Columbus, like all of his educated contemporaries, knew of the Classical Greek concepts, and it was his reading of Aristotle, Seneca, Ptolemy, Strabo, Pliny, and Captionius that formed his notion that he could sail westward from Europe directly to “the Indies.” He was influenced directly by these works as well as by interpretations of them on the part of the fifteenth-­century cosmographers Pierre d’Ailly and Paolo dal Pozzo Toscanelli, who, decades before 1492, supported the concept of a westward voyage to the Far East.2 The case has even been advanced that Columbus had already heard, from an unidentified ill friend, that 28 / Chapter 2 friend’s report of his own, slightly earlier, “prediscovery” of the New World— a rumor discussed in the sixteenth century by the Spanish historian Gonzalo Fernández de Oviedo y Valdés.3 Another myth is that Columbus, who did his own navigating in 1492, succeeded because of his use of all the most up-­ to-­ date developments in position-­ finding and course-­ plotting. These included innovations allegedly made under the aegis of Henry (Enrique) “the Navigator,” the Portuguese prince who, well before Columbus’s first voyage, dispatched ships to explore the coast of West Africa. Among these innovations was the use of the astrolabe and the backstaff to determine latitude. As a navigator, however, Columbus was not, according to J. H. Parry, “in the forefront of new developments, or even abreast of them. He knew very little about celestial navigation; nothing, apparently, of the new Portuguese method of measuring latitude by solar altitude. He understood the principle of latitude-­ sailing, but some of his Polaris observations, which he recorded , were badly out. Even his dead-­ reckoning, on his outward passage, left something to be desired.”4 As noted, the myths about Columbus include the belief that the admiral was the first to conclude that Earth is a globe, not a flat plane off whose edge a ship venturing too far from land would fall. The idea that church officials espoused the flat-­ earth notion and had problems with Columbus’s contrary views derives from Wash­ ing­ton Irving’s 1828 book History of the Life and Voyages of Christopher Columbus, which took considerable license with fact. The notion of medieval resistance to the concept of Earth’s globular nature became popu­ lar gospel. It persists to this day and is still found in influential modern books.5 But in truth, in Columbus’s time scholars were nearly unanimous in the opinion that the earth was spherical. Even Columbus’s standard biographer, Samuel Eliot Morison— no friend to the notion of pre-­ Columbian discoveries—recognized this: “of all the vulgar errors concerned with Columbus, the most persistent and most absurd is that he had to convince people ‘the world was...