The heart-shaped projection had been used several times before by various cartographers, but the map that it produced was essentially one to be kept in the study, rather than taken onto the high seas. It remained impossible to plot a straight course across it on a ship's chart-room table. Thus Mercator's effort was a map to be admired rather than used. The challenge of mapping the world for the navigator still remained.
Chpater Nine
The Greatest Globe
in the World
AT HOME IN LEUVEN, in the house by the Augustinian monastery, Barbe gave birth to her third child, Dorothee, in 1539, by which time Arnold was two, and Emerance a year old. Mercator's family was growing, but during the months before Dorothee's birth, he had spent weeks at a time away from home as he began an ambitious survey of much of the nearby region of Flanders. It was a fortunate choice of subject. Before it was even off the drawing board, the map was purchased by a group of leading merchants in the city of Ghent, who planned to use it as a peace offering.
Ghent, the birthplace of the emperor, had always been a rebellious, free-minded corner of the Habsburg inheritance, and when in 1538, Charles's regent, Mary of Hungary,* sent her tax collectors in to raise money to support Charles's wars against France, the hard-pressed townsmen had rebelled. They seized control of the walls, expelled the city authorities, and declared effective independence from the empire. For a few short months, a heady sense of freedom swept the city, in an open challenge to the religious as well as the civil powers. Preachers questioned the basic tenets of Catholic doctrine, while actors and minstrels in the streets lampooned the greed and corruption of the Church. For that short time, with Charles far away in Spain, there seemed to be nothing that the newly independent Ghent could not do.
When a message arrived late in 1539 that the emperor was on his way to visit, no one supposed, whatever his emotional ties to his native city, that he was making a sentimental journey. Charles was coming to exact retribution and reinforce the power of the empire. Some of the more headstrong of the rabble that had seized control were prepared to face him, but the levelheaded merchants of the city began to search for a way to divert his anger. They had perhaps three months in which to do so; in October 1539, Charles left Spain at the head of his army, marching to Flanders.
Ghent's brief freedom had seen the production of a woodcut map showing the city as an independent bastion of liberty, dominating the whole of Flanders. As an insult to Charles V, it could hardly have been more direct—and it gave the merchants an idea of how the city might prove its loyalty. Mercator's map could be presented to the emperor as a gesture of civic submission.
Mercator himself was enthusiastic. He had already done much of the work, and there was no better way of bringing himself to the notice of the rich and powerful than by becoming known at the imperial court. Mercator's map, even though it was never completely finished, was not only said by many contemporaries to be a better description of the topography of Flanders than anything else that had been produced; it was also an abject offering of abasement to imperial power. Ranged along top and bottom were portraits of the successive counts of Flanders, culminating in Charles himself. Flanders was part of his Burgundian inheritance, and the map's legend declared deferentially that it had always willingly bent the knee to its rulers.
Neither map nor flattery did much good for Ghent. Charles was not to be diverted from his purpose either by sentiment for his birthplace or by the sycophancy of the burghers, and his forces fell upon the town in a storm of terror, torture, and executions. Thirteen of the leading rebels were executed, great swaths of buildings were pulled to the ground, and an imposing fortress constructed on their ruins to remind the townsfolk who their master was. A long procession of burghers, guildsmen, and other citizens marched barefoot through the town, nooses around their necks, to beg on their knees for pardon from the emperor they had challenged. Yet while Ghent suffered, Mercator prospered. His map of Flanders brought him to the emperor's notice, the first work by his hand alone that had been received as a gift at the imperial court.
WHILE COMPLETING THE FLANDERS MAP, Mercator had been working on an instrument commissioned by one of his acquaintances from the university, Antoine de Granvelle, then already archdeacon of Besancon and of Cambrai, and newly appointed bishop of Arras. Exactly what he made for him is unclear; he described it as a calvaria, which could refer to a skull-like arrangement of three concentric rings originally designed by Gemma Frisius. Each ring was marked off in degrees to enable an astronomer to take sightings of planets and note the angle between them, but the instrument's most distinctive feature was that it was small enough to be slipped into a man's luggage.
Mercator composed a letter in 1540 to accompany the piece. It explained the difficulties he had experienced in carrying out the work and hinted delicately that he would welcome financial support. Lack of equipment, he said pointedly, meant that the calvaria had taken him much longer to make than he had hoped. "Since I had little equipment and I wanted to finish it, I had to seek engraving tools, which took a long time to make since as usual we had to go to other and varied shops," he wrote. "But Your Grace will count it to the good, when you see that the loss of time (if such it is) has been made good by my skill."Still in his twenties, Mercator had the outspoken confidence of a master craftsman combined with the well-modulated sycophancy of an ambitious tradesman—all of it finely judged to impress a wealthy and influential sponsor. His assurance extended far beyond mere technical competence. To Granvelle, Mercator spoke with easy familiarity about the rapidly changing state of geographic knowledge. He had taken great pains to compare the geography of the ancients with the discoveries of recent decades, he told the bishop. "Having done this diligently, I see we are still confounded by great errors . . . . How much we err in the Far East, anyone who reads Marco Polo the Venetian attentively will know."1
Many of the claims in Marco Polo's account of his travels were mocked when his book first appeared at the end of the thirteenth century— it was known as // Milione (the Million Lies)—but manuscript copies had already been studied for more than two centuries by Mercator's time. Columbus was only one explorer to accept Polo's exaggerated guess of how far he had traveled overland on his way to the imperial palace of Kublai Khan in China.
Even if his account of his twenty-four-year adventure was partly fantasy, his influence was clear in the maps that were drawn during the fourteenth century, when the story of his travels had been widely spread. New maps, like that on the globe produced by Gemma, Gaspard, and Mercator a few years earlier, showed a much better understanding of the size and shape of the Indian peninsula than Ptolemy had achieved, and many of the islands of the East Indies were much more accurately drawn, in line with Marco Polo's descriptions. But Mercator resolved to winnow out still more truth from the errors, exaggerations, and misconceptions. Along the coastline of southern Asia, for instance, he believed after reading Marco Polo that there were four peninsulas, not three as Ptolemy had described, and as he had shown on his own map three years earlier. In addition, parts of Africa needed correcting, as did Madagascar and many of the islands he had shown before; and although he had no significant changes to make to the coastline of America, more details had emerged to start filling out the interior.
"In short, I am drawing all the places that others have revealed, and fashioning a globe which will be bigger than any before, but which will not be too big to be used," he declared confidently to Granvelle.2
The weakness of his world map had been its design rather than its geography, and its lesson was that projecting the world onto a flat surface seemed to be an intractable problem of mathematics. The answer he looked for was that of a craftsman rather than that of a mathematician. In Gemma Frisius and Gaspard van der Heyden he had had two of the finest teachers he could have found for the techniques of globe manufacture, and Franciscus Monachus may well have shown him his globe in Mechelen years before.
Mercator had told Granvelle in
August 1540 that his work would be completed in three months from the date of his letter. It was an optimistic promise, as his predictions always tended to be: Whether because he still lacked the tools he needed, or because he simply underestimated the amount of work involved, the globe was not finished until the following year.
Barely three years after finishing his first map of the world, the information that he had at his disposal had grown so much that whole areas had to be changed. His globe had to be bigger than any made before because there was so much to put on it. His intention was clearly to make it a usable tool for navigation, indispensable not just to students but to sailors as well. He prepared instructions to enable a traveler to find his position by means of the stars, and parts of the globe were crisscrossed by loxodromes (lines showing the course that a ship would take if it followed a constant compass bearing)—an idea he took from the sailors' portolan charts of their coastal journeys. He was the first globe manufacturer to include such lines to help navigators meet the challenge they had always experienced in marking a course on the curved surface of a globe. But the way the loxodromes curved gently toward the poles was a graphic illustration of the continuing problem of projection. Lines that were straight on the map were curved on the globe.
All this, effectively a renewed, updated, and adapted version of his map of the world, was to be engraved and printed on twelve carefully shaped gores—narrow, pointed ovals of paper joined at their centers, precisely where the equator would lie on the finished globe. Each one was designed so that its length was slightly less than half the circumference of the globe and its width one-twelfth its circumference. Once the paper was wet, stretched, and pasted down, the gores would precisely cover the plaster base.'3
At least, that was the hope. The printing was a challenge for the most sure-handed craftsman: Pasting them down would reveal not only the slightest irregularity in the surface of the globe but also any inaccuracy in the engraving. Names could be, and generally were, inscribed within single gores, but coastlines, rivers, and mountains—all the myriad fine lines that made up the map—had to match perfectly when the edges of paper were laid together. For a perfectionist like Mercator, this required the most exquisite patience. The completed gores also provided another frustrating illustration of the persistent difficulty that was troubling him. Laid out flat, the form of the map itself could hardly be seen because of the widening gaps between each delicately cut gore. Only when they were finally pasted down did the design appear as if by magic, when the lines of longitude, which had curved inexorably away from each other on his desk, wrapped themselves around the globe. To make a true, flat map, those curving lines of longitude would have to be straightened. The problem was clear, but there was no apparent solution.
The structure of the globe itself was simple, strong, and workman-like. Gemma's cardboard construction may not have proved robust enough for Mercator's purposes, and he—or more probably a craftsman in his workshop—started by modeling a skeletal globe with flexible slats of wood, bent to shape. A cloth cover was pasted over them, and then that was spread with a thin layer of plaster. A final quarter-inch coat of mixed plaster, sawdust, and glue was then applied, accommodating any minor irregularities to produce a perfect sphere. When that coat was dried and smoothed, the precious paper gores were pasted down, colored by hand, and varnished. Copies of the actual map could be printed from the original engraving, but the painstaking work of building the globe on which to paste it had to be repeated for each new specimen. The little workshop beside his house is unlikely to have turned out more than two or three a week.
For all his skill, and for all his efforts to cover his globe with loxodromes to make it easier to follow a course, any globe was almost impossible to use for navigation at sea. The difficulties were immense. Mercator had produced the largest printed globes ever made, but they were still only just over sixteen inches in diameter—practically a toy when compared with Strabo's pronouncement more than fifteen centuries earlier that a globe should be at least ten feet in diameter, or with the world maps measuring twenty-five square feet and more that were being routinely printed. Ptolemy, while praising the accuracy of the globe as a way of reproducing the map of the world, had pointed out this problem as well. A globe, he said, was either too small to contain enough detail or too big to be of any practical use.
There were mechanical problems, too, implicit in the construction of anything as delicate as a revolving globe for everyday use. If it lost its balance, or the rod on which it was pivoted were to work loose with constant turning, the globe would be useless—a disaster for any navigator relying on it far from land. If such weaknesses were evident when the globe stood firmly on the workbench, they were likely to be still more troublesome when a small wooden vessel was tossing on the high seas. The experience Mercator had gained in Gemma's workshop, together with his own technical skill, meant he could minimize the problems. Care in fitting the rod through the plaster globe and into the wooden stand, and the most rigorous measurement of the thickness and regularity of the plaster coating, made his globes more reliable, but there were other problems that the most skillful manufacture could not rectify. Globes were bulky and awkward to handle, and due to their shape, it was often impossible to get an overview of the planned journey: The final stages of a long voyage could be revealed only by turning the globe on its axis. On a map, a navigator could at least see the whole world at a glance, whereas one side of a globe was always hidden from him.
In the end, while Mercator may have designed his globes for sailors, most of them went to stand as elegant and fashionable pieces of furniture in the homes of the wealthy, and Mercator's workshop found it hard to keep pace with demand for new globes over the next few years. Yet even as he achieved a commercial success, Mercator remained fascinated by the theoretical and practical problems his work kept throwing up. That fascination extended beyond the practicalities of cartography and the use of the globe by navigators.
WHILE SAILORS IN THE AMERICAS were discovering the limitations of the ancient conception of the world, astronomers in Europe were drawing new, staggering, and provocative conclusions about the place of that world in the heavens. Explorers and astronomers shared a growing awareness that knowledge might stretch farther than they had ever dreamed. The key to understanding the new discoveries in the skies, as well as those on Earth, was the globe.
In 1551, ten years after he started making his terrestrial globes, Mercator would produce a matching celestial globe, mounted, like the earlier one, in a carved, four-pillared polished wood stand.4The various constellations— forty-eight made up from the 1,022 stars listed in Ptolemy's thirteen-volume work on astronomy, the Almagest, and two new ones— were illustrated by finely etched human and mythological figures. He was not the first manufacturer to produce matching pairs of terrestrial and celestial globes, but as Mercator's work acquired an unprecedented popularity and fame throughout Europe, customers began to demand that their globes should come in pairs. Globe makers for the next three centuries followed this example.
Like its predecessor, the celestial globe was the work of a dedicated artist, and he remained just as painstaking about the accuracy of his map of the stars as he had been in preparing his terrestrial globe. The telescope was unknown to the astronomers of the sixteenth century; not until 1609 did Galileo, in Italy, first hear of the new invention in northern Europe that seemed to bring heavenly bodies closer than the human eye had ever seen them. The only instruments available in Mercator's day were those such as the astrolabe and the cross-staff that could measure and track the paths of the heavenly bodies. The study of the stars had always required as much mathematics as observation.
Even more stultifying than the lack of accurate instruments was the conviction of the Catholic Church that only a universe in which the stars and planets revolved around the heavens could do justice to the magnificence of God's Creation. Aristotle had declared that the Earth was the center of the universe; so had Ptolemy. To
challenge that official wisdom was to defy the Church and to invite the attentions of the Inquisition. Mercator's knowledge was based largely on Ptolemy's fourteen-hundred-year-old view of the heavens, but just as he assimilated the latest discoveries of the Portuguese and Spanish sailors into his terrestrial globe, so he studied the most recent astronomical thinking of his day as he plotted the design of his latest creation.
The ideas of Nicolaus Copernicus, a Polish-born mathematician, doctor, clergyman, and lifelong astronomer, were revolutionary enough to have been passed around by word of mouth for more than thirty years. He believed that Aristotle and the Church were wrong, and that the Sun and not the Earth was at rest in the center of the universe—a suggestion that shook traditional science and theology to its roots. Copernicus's detailed account of his theory, in the book De Revolution-ibus Orbium Coelestium (On the revolutions of the celestial spheres), did not appear until 1543—according to written accounts, Copernicus saw a printed copy for the first time as he lay on his deathbed in Frombork, Poland—but he had been working on the ideas that it contained for some three decades.*
Once again, Mercator was determined that his work should be at least as much a precise tool for professional observers as an intriguing ornament for display; his was the first globe to be based on Copernicus's theories. In mapping the stars, as in mapping the Earth, he consciously moved away from the traditional impressionistic, subjective idea of cartography toward a new and more scientific concept.
At the same time, he was also developing an artist's fascination with the finer details of his work—an interest in the beauty of its design and the delicacy of its execution for their own sake. The artistry, the flowing lines, and the delicate textures of the mythological figures engraved on Mercator's globes were far in advance of anything that had been produced before. He wielded an engraver's burin over the copper with the delicacy of a painter touching a canvas with his brush. The muscles of Sagittarius on the globe seem to strain as he draws his bow, the bear that represents Ursa Major appears to have fur, and the feathers of Pegasus, the winged horse, are individually picked out. With his celestial globe, completed in 1551 when he was thirty-nine years old, Mercator claimed his place as the finest cartographic engraver of the age.
The World of Gerard Mercator Page 10