The World of Gerard Mercator: The Mapmaker Who Revolutionised Geography. Andrew Taylor

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СКАЧАТЬ nameless and unknown thinkers. Nonetheless, however much or little of them had actually been written by Ptolemy himself, they were a virtual synthesis of classical scientific knowledge.

      The Geographia concentrated on the arts and skills of mapmaking, discussing the comparative merits of flat maps and globes, and arguing through the mathematics of how a map should be constructed and how the world could be divided into the three continents of Europe, Asia, and northern Africa. The great undiscovered continent that Ptolemy believed lay to the south turned the Indian Ocean into an inland sea, and in the East, the known world petered out in the unexplored lands beyond the Ganges. West of the Pillars of Hercules, at the mouth of the Mediterranean, of course, he described nothing but sea and a few scattered islands.

      Fresh versions appeared year by year, with cartographers adapting and expanding Ptolemy’s work. An edition was printed in Cologne in 1475 without maps; only two years later, the interest and the technology existed to prepare a version in Bologna that included twenty-six copper engravings based on Ptolemy’s text. By the time Mercator was working, the book’s reputation was established among scholars, even though the great voyages of the fifteenth and sixteenth centuries were already demonstrating its limitations.

      For all the dedicated work of the monastic copyists, it was the development of printing that allowed Ptolemy’s work to be widely read in Europe. The impact of Johannes Gutenberg’s first press with movable type in the 1450s is hard to exaggerate. In the Low Countries alone, more than four thousand different books were produced in the first decades of the sixteenth century; there were in excess of 130 printers there, half of them in the thriving city of Antwerp.

      Ptolemy’s Geographia was only one of a range of classical works that flooded off the new presses to feed the public’s apparently insatiable appetite. As these books were shipped around the continent, they invigorated and inspired learning not just in the palaces, monasteries, and great houses that had always collected rare and expensive manuscripts, but also in the studies of poor students. Without the explosion of printing, Mercator would never even have seen many of the books that enthused him at Leuven. He would certainly never have gathered around him the personal library in which he delighted in the German city of Duisburg.

      However, for all the excitement that the rediscovery of Ptolemy’s Geographia stirred up, his three continents soon could no more be accepted as they stood than could the old T-O maps or the mappaemundi. There had been rumors for centuries of scattered islands far away to the west, but no one had any idea of the vast extent of the newly discovered land. Just twenty years before Mercator was born, the discovery of America had revealed a new world of which Ptolemy and his predecessors never dreamed, confounding the ancient view that the Earth was limited to the three continents of Europe, Asia, and the strange and mysterious Africa.

      While the actual extent of the world would have astonished the ancients, its round shape had been known since well before Ptolemy’s time. Various early Greek philosophers had produced detailed arguments to prove that the Earth was cylindrical, disk-shaped, or rectangular, that it was cushioned in compressed air, or that it was floating on water. Yet by 250 BC, Eratosthenes of Cyrene, one of the scholars who devised a rudimentary grid of latitude and longitude, had not only accepted the idea of a spherical world but had studied the stars to calculate its circumference.¹

      Strabo, another Greek geographer and historian, who worked before Ptolemy in the library of Alexandria in the last century BC, had a severely practical turn of mind. The world could be represented on a globe, he declared, but the globe would have to be ten feet across to show all the necessary detail. The work of Ptolemy himself a century or so later in devising projections shows that he had no doubts either about the curvature of the Earth. For accuracy, he concluded, there was no substitute for a globe.

      Ptolemy had described in great detail how it should be done, with the globe suspended between two poles connected by a semicircle, which should almost touch its surface. Such an arrangement, he wrote, had advantages and disadvantages when compared to his own efforts at working out a way of projecting a map onto a flat surface: “It preserves the world’s shape, and avoids the need for any adjustment of it, but it hardly provides the size needed for containing most of the things that must be marked on it, nor can it allow the entire map to be shown from one vantage point.”²

      Like his books, Ptolemy’s endorsement of the globe was lost to Europeans in the Middle Ages. There are tantalizing mentions in classical literature of various globes, including small representations of the Earth enclosed within glass spheres which showed the constellations, like the pair Charles V, the Holy Roman Emperor, would later demand from Mercator. But if the Greeks or Romans ever made large detailed models of the spherical Earth, in line with the recommendations of Ptolemy and Strabo, none of them survived. European craftsmen produced armillary spheres in which concentric metal rings would demonstrate the supposed motion of the planets around the Earth, but they showed no interest in the idea of a terrestrial globe.

      The Arabs, on the other hand, turned Ptolemy’s words into reality. Many of them used his Almagest rather than the Geographia and showed the stars, not the Earth, in their work. In Florence’s Museum of the History of Science, there is an engraved metal sphere about eight inches in diameter, with 1,015 stars marked on it according to Ptolemy’s descriptions, made by Ibrahim ibn Said al-Sahli al Wazzan with his son Muhammed in Valencia, in Moorish Spain, in the late eleventh century.

      Such magnificent celestial globes were often carved on brass or silver, intended for a study rather than the navigator’s desk, but the Arabs must have made terrestrial globes as well. None survives today, but Christopher Columbus said in his ship’s log that he had seen globes of the world on which the island of Cipangu, or Japan, was marked.

      The Arab globes were also studied by Martin Behaim, a Nuremberg traveler and adventurer who set out to copy the technique and manufacture a globe of his own toward the end of the fifteenth century. Behaim claimed to have sailed the coasts of Africa with the Portuguese explorers, and to have seen the globes at the Royal Observatory, which had been established in about 1420 by Portugal’s Prince Henry the Navigator at the southern port of Sagres.³

      One advantage that neither Strabo, Ptolemy, nor their Arab imitators had mentioned was that the globe offers a dramatic way of demonstrating the circularity of the Earth to a layman – an investor, for instance, who might be persuaded to put money into an expedition. The Portuguese had demonstrated that there were riches to be won in the East, and in order to show the wealthy financiers of Germany how easily the Indies could be reached by sailing west, Behaim constructed the first modern globe known to have been produced in Europe. It was intended not for scholars or sailors but for bankers.

      Behaim, the son of a German nobleman, had been packed off to Portugal as a young man to gain experience as a businessman, but had spent more time there among the sailors and navigators around the docks than in import and export. He had a healthy disrespect for authority – in his youth, he was said to have served a month in prison for dancing at a Jew’s wedding during Lent – but he also had a shrewd commercial eye. He was fascinated not only by what he had seen of the voyages of discovery but also by Prince Henry’s Arab globes.

      None of those globes is known to have survived, but the Arabs had proved that Ptolemy’s theory worked. A globe to show how the western ocean lay between the continents of Europe and Asia was clearly the way to impress a skeptical audience with the practicality of sailing west to reach the Spice Islands in the East. The Portuguese controlled the passage around the southern coast of Africa, and huge costs were involved in the ancient overland trails from Asia through Arabia to the Mediterranean. The globe – which Behaim called his erdapfel, his earth-apple – was a striking demonstration of another route.

      Today, Behaim’s brainchild is the most famous exhibit in Nuremberg’s Germanisches Nationalmuseum,⁴ darkened by age and scarred by the attentions of well-meaning СКАЧАТЬ