Conquering the Pacific
Page 4
This system worked well enough until Portuguese navigators ranged too far south. In 1471 they crossed the equator and observed anxiously how the North Star dipped below the horizon and disappeared entirely from view. Deprived of their guiding star, pilots and cosmographers began scanning the southern sky for a suitable replacement and eventually found the Southern Cross. Yet this transition took decades. In the meantime, King João II summoned his experts, who set out to devise a far more elegant and sweeping solution to the problem of establishing latitude.20
Like any other star, the Sun could serve as a reference to determine north-south distance. But the great luminary posed two challenges. First, while the North Star remains almost perfectly stationary (because Earth’s rotation axis is closely aligned with the North Star), the Sun describes an enormous arc across the sky over the course of the day. Its altitude must therefore be measured exactly at noon. Fifteenth-century navigators did not possess accurate clocks, so they had to start measuring a half hour or so before noon, taking the altitude continuously until the Sun had passed its zenith and was clearly on the way down. Of all the observations, navigators then selected the highest one, evidently corresponding to noon. This altitude was very high but almost never exactly ninety degrees because most places on Earth are either to the south or to the north of the spot where the noontime Sun is directly overhead and forms a perfect right angle with respect to the horizon. The residual shadow, however small, could therefore be used to determine north-south distance or latitude.21
All of this was possible in theory if not for the second complication. The Sun’s path across the sky changes during the year. As we know, in the summertime, the Sun’s path across the sky is higher and longer and thus the days are equally longer, while in winter, the Sun’s trajectory is lower and shorter and consequently the days are shorter. This happens because Earth orbits around the Sun at an angle of 23.5 degrees. This slight axial tilt makes the wonders of the seasons possible, but it also causes the spot on Earth where the Sun is directly overhead at noon to wobble north and south—from the Tropic of Cancer to the Tropic of Capricorn and back again in the course of the year. This constant north-south displacement of the point on Earth that is directly underneath the Sun is called solar declination. In practice, it constrained the applicability of the method of establishing north-south distance to a two-day window. “If you want to know the ship’s reckoning by the altitude of the Sun, take the Sun at noon when you leave port,” instructed one of the navigational manuals of that era, “and after one or two days at sea, take the altitude of the Sun again and you will note the difference between one and the other.” Beyond this two-day window, however, the solar declination would render any estimations dangerously off. It was a major limitation. Nevertheless, one could still envision a stunning mathematical solution. Astronomers could calculate, in advance of the voyage, the Sun’s declination for every day of the year and compile a so-called declination table that pilots could then use to determine latitude accurately, on any day included in the table, anywhere in the world.22
Land-based astronomers aided by spherical models of Earth surrounded by movable rings representing the trajectories of various celestial bodies had been able to determine latitude by the noontime altitude of the Sun and perform all the necessary calculations to take into account the solar declination for centuries. Yet such involved procedures had been beyond the capabilities of working pilots, few of whom had any formal training in astronomy or mathematics. Some were actually illiterate. Therefore, devising a simple, workable declination table was the last obstacle before unleashing the full power of solar navigation; and King João’s experts were closing in on a new system. Like many other innovations achieved collectively, this one has given rise to a great controversy about who deserves the credit, especially given the varied national backgrounds of the king’s experts. One of them was a merchant from Nuremberg, Germany, named Martin Behaim, who had arrived in Lisbon a few years earlier and taken part in various voyages of exploration. Behaim was very well versed in mathematics and astronomy and “boasted about being a disciple of Johannes Regiomontanus, a famed astronomer among the professors of this science,” according to the preeminent Portuguese chronicler of that era. On the strength of this contemporary endorsement, later scholars have considered Behaim the chief innovator—an open-and-shut case of German knowledge diffusing to a peripheral nation.23
Yet a close examination of the declination tables reveals that the source was neither Behaim nor Regiomontanus but two Jewish mathematicians from the Iberian Peninsula. The older and more established of the two was a Spanish astrologer from the university town of Salamanca named Abraham Zacuto, who devoted several years of his life to calculating sixty-five astronomical tables that tracked the positions of various celestial bodies. By all accounts, Zacuto was a phenomenal mathematician and astronomer (in addition to being a rabbi, lexicographer, and historian), and his tables were nothing short of a tour de force. He lived in Spain in the early 1480s and therefore was not among King João’s circle of experts—although, after the expulsion of the Jews from Spain in 1492, Zacuto would relocate to Lisbon and accept the position of “astronomer to the king.” Even though he was not physically present, his calculations had been well known in Jewish astrological circles throughout Iberia at least since 1478, when a Hebrew version of his text and tables began circulating. Yet Zacuto’s contribution could have gone unnoticed had it not been for the second key figure, a Portuguese Jew named José Vizinho. He happened to be among the king’s experts and may well have been a disciple of Zacuto or at least well acquainted with his work. Vizinho instantly recognized the utility of Zacuto’s numbers. The first five tables provided the Sun’s declination for the years between 1473 and 1476. These results could not be readily applied after 1476 because his calculations were thrown off by the intervening leap year. Nevertheless, it was possible to update Zacuto’s declination table. On his own or with Zacuto’s assistance, Vizinho compiled a new table, starting in March 1483 and ending in February 1484.24
Thus began a new method of navigation by the altitude of the Sun. It was better than anything the Portuguese—or anyone else around the world for that matter—had ever used before, as it allowed pilots to work in broad daylight anywhere in the world and resort to very simple rules and straightforward tables to determine latitude. Even today, short of using a global positioning system, sailors who want to be protected against electronic failure carry published declination tables (The Nautical Almanac) and sextants to determine their latitude at sea. The tables and sextants (which superseded the astrolabes) may be more accurate these days, but the method has remained the same for more than half a millennium.25
This innovation was great news in the community of navigators in Lisbon—Columbus among them. He followed closely as Behaim, Vizinho, and the other experts arrived at a straightforward system of finding latitude that all pilots could use. In 1485, King João dispatched Vizinho to Guinea (Sierra Leone) to measure the height of the Sun and conduct an astronomical survey of that coast. Columbus witnessed the session when the mathematician submitted his findings after his return. As the future Admiral of the Ocean Sea reported, “Master José [Vizinho] gave an account of everything to His Most Serene Highness, the King of Portugal . . . and the king sent navigators to Guinea and other places and it was always found that the observations were in agreement with Master José’s measurements.” The method of navigating by the altitude of the Sun would prove essential to Columbus during his New World voyages and to those who would later venture into the Pacific, as we shall see.26
Columbus was thoroughly transformed in Portugal, not only by the nautical knowledge he gained but also by his growing obsession with the idea to “reach the east by way of the west.” In 1483 or 1484, the future Admiral mustered enough courage to explain his project before the Portuguese king and to make a formal proposal. King João II heard him out but ultimately turned the matter over to his expert mathematicians and
astronomers. They were not impressed. According to the leading chronicler of that era, “They all considered the words of Cristovão Colom as vain and founded on imagination and things like the Isle of Cipango [Japan] of Marco Polo.” It did not help that Columbus grossly underestimated Earth’s size. As far as the king’s experts were concerned, this Genoese petitioner was bound to perish in the middle of the Ocean Sea well before reaching Asia—as would have undoubtedly happened had he not stumbled first on America. Finally, Columbus’s plan was out of sync with Portugal’s fundamental strategy of going down and around the African coast to beat a path toward India and then to the Far East. Compared to this systematic approach, Columbus’s wild dash across the Atlantic seemed like a distraction at best and likely a foolish waste of lives and money.27
With the double blow of no hope of royal sponsorship and Felipa’s sudden death in 1484, Columbus decided to leave Portugal and try his luck in Spain. He submitted his proposal to the Catholic sovereigns, Ferdinand and Isabella, in 1486–87 and again in 1491. They had it examined by a junta of experts much as had happened in Portugal. The Spanish elephant was nothing if not lucky. The experts at Valladolid and Santa Fe raised objections—some reasonable and others less so—but in the end left the door open for royal support of this harebrained scheme. The rest of the story is well known. Perhaps the Spanish monarchs sensed that this Genoese man, steeped in the latest Portuguese navigational methods and with real sailing experience in the Atlantic, would be as good a bet as any. Fresh from their victory over the last Muslim enclave on the Iberian Peninsula, Ferdinand and Isabella signed off on the project in the spring of 1492.28
Columbus’s exploits loom so large in our understanding of the past that other great discoveries recede into the background. In truth, any reasonable observer at the turn of the sixteenth century would have conceded that, even after Columbus’s famous voyages, Portugal’s lead in the global race had widened until becoming almost unassailable. Portuguese navigators reached the tip of Africa in 1488 and found the route to India a decade later. King Manuel I of Portugal took pleasure in writing lengthy letters to the Spanish monarchs, his in-laws and rivals, informing them, “Our Lord has miraculously wished India to be found” and telling them about the spices, precious stones, elephants, exotic peoples, and the immensely profitable trade carried on there. “We are still awaiting news from the twenty-five ships that we sent the previous year [1502],” Manuel gloated to Ferdinand and Isabella in one of his letters, “and after they come back in September there will be time to send some more.”29
In the meantime, Spain could point to only a few Caribbean islands and inklings of an unknown continent, but no precious spices, porcelain, or silk. The new lands did offer some gold, but they never replaced the original quest of finding a western approach to the incalculable riches of the Far East. Spaniards explored the continent blocking their way, looking for a passage that would connect the Atlantic with the Pacific. They came up empty-handed until Fernão de Magalhães—a Portuguese defector like the Afro-Portuguese pilot Lope Martín a generation later—put Spain back in the race. Ferdinand Magellan had come of age during Portugal’s torrid expansion into Asia in the 1500s. Yet he had a falling-out with the Portuguese crown and went knocking on neighboring doors. It is difficult to overstate the significance of Magellan’s move to Spain.
Magellan caught up with the roving Spanish court at the town of Valladolid. For someone accustomed to the sound of waves and the proximity of sailboats, it must have been strange to have to journey to the middle of Iberia to propose a maritime venture in a town surrounded by agricultural fields and interminable plains. He did not arrive alone but was accompanied by two brothers, Rui and Francisco Faleiro, both cosmographers whose reputations exceeded Magellan’s. The trio complemented one another well. Magellan came across as a man of action who had fought in India, Malaysia, and North Africa, while the Faleiros were armchair academics. As they waited for an audience with the Spanish king in February and March of 1518, the Portuguese visitors grew unsettled by what they heard. The new monarch, Charles I, was an awkward eighteen-year-old who had come from Belgium just a few months before and had great difficulty communicating in Spanish let alone Portuguese. Worse, the trio had to tread carefully in a court riven by a power struggle between Charles’s advisers recently arrived from Belgium and the old Spanish officials from the previous monarch.30
Interestingly, during the early negotiations Rui Faleiro rather than Magellan emerged as the leading voice. The older of the two Faleiro brothers, Rui was deferentially referred to as a bachiller (or bacharel in Portuguese), the highest university degree one could get at the time. Before leaving Portugal he may have been considered for a new chair in astronomy established at the oldest university in the kingdom (what is now the University of Coimbra) by the Portuguese king himself. It was the highest position in the field. One of the reasons that perhaps impelled Rui Faleiro to join Magellan in Spain was being passed over for this prestigious appointment; academic rivalries and pettiness were already alive and well in the sixteenth century! In spite of this setback, and notwithstanding a rumor that “he was possessed by a familial demon and in fact knew nothing about astrology,” Rui Faleiro remained a top European cosmographer. Sixteenth-century Spanish chronicler Gonzalo Fernández de Oviedo described Rui Faleiro as “a great man in matters of cosmography, astrology, and other sciences and humanities.” There is little doubt that he was extremely accomplished if mercurial and mentally unstable. Rui’s younger brother Francisco Faleiro was just as talented and would go on to find long-term employment in Spain as a leading nautical expert. Together the two Faleiros and Magellan were very credible petitioners.31
On the day of the audience, Magellan and Rui Faleiro arrived not with charts as would have been expected but with “a globe that was very well painted and showed the entire world, and on it Magellan traced the route that he would follow.” The two petitioners explained that they intended to cross from one ocean to the other “through a certain strait that they already knew about.” Even though the globe was detailed, the portion of South America where the strait was supposed to be had been left intentionally blank. Magellan and Faleiro had evidently taken some precautions in case anyone present at the audience should wish to steal their project.32
Their knowledge of a passage between the oceans—the alpha and omega of many New World explorations—would have been more than enough for the royal sponsorship. But Magellan and Faleiro went further. As one witness at the audience recounted, “They offered to demonstrate that the Moluccas [Spice Islands] from where the Portuguese take spices to their country are on the side of the world that belongs to Spain, as agreed by the Catholic Monarchs and King Juan of Portugal.” The 1494 Treaty of Tordesillas had established a line of demarcation running from pole to pole through the Atlantic but did not contemplate extending the line to the other side of the world. As Portugal and Spain, however, had continued to sail in opposite directions, such an antimeridian had become necessary. Measuring longitude or east-west distance was still extraordinarily difficult in the early sixteenth century, so no one knew quite where to draw this line in the distant Pacific. All the same, in the early 1510s the Portuguese had planted trading forts in Malaysia and the Spice Islands while Spain had stood by helplessly. Yet in the winter of 1518, Magellan and Faleiro had become persuaded that the Spice Islands were actually on the Spanish side, a conclusion all the more startling in Spain because it was coming from these top Portuguese navigators and cosmographers.33
Magellan had become convinced that the Spice Islands were on the Spanish side after carefully studying the Portuguese sailing charts (mostly unavailable to Spanish navigators). By adding up the east-west distances of the passages from Portugal to the tip of Africa, on to India, and all the way to Southeast Asia, he had persuaded himself that the Spice Islands were simply too far away and so beyond the Portuguese hemisphere. This in itself was intriguing. But during the audience with the Spanish king, the two p
etitioners also promised to confirm this potentially explosive geopolitical idea by means of a more technical method. For this part of the proposal, Magellan turned to his partner, the extraordinary Rui Faleiro.34
Measuring east-west distance and finding the antimeridian was possible in theory. One obvious method would have been to take the time along the Tordesillas line, travel to the other side of the world, and locate a line exactly twelve hours apart. Unfortunately, this solution required a timepiece unaffected by the pitching and rolling of a ship, a mechanical feat that would not be achieved until the eighteenth century. Navigators also tried to find the antimeridian by means of astronomical events like eclipses visible simultaneously in different parts of the world. Yet pilots could never depend on such rare events for their daily work.35
Instead of looking at the sky, the two Faleiro brothers focused on an earthly phenomenon. On long voyages, Portuguese navigators began observing how the compass needle did not align exactly with “true north” as shown by the North Star. Instead, it often pointed slightly to the left or the right of it. Not everyone agreed that such misalignments between magnetic and true north were even real. In those days, compass needles had to be detached from time to time from the boxes where they were suspended and re-magnetized by striking them against a lodestone. Therefore the variation was often chalked up to de-magnetized or faulty needles or otherwise explained away by the idiosyncrasies of Genoese or French compasses or some other maritime lore.36