Mendaña’s orders from his uncle, the Spanish Viceroy, were to convert any ‘infidels’ he encountered to Christianity, but the expedition was certainly not motivated entirely by religious zeal. According to Inca legend great riches lay on islands somewhere to the west. Were these islands perhaps outliers of the great southern continent that was believed to lie hidden somewhere in the unexplored South Seas? Mendaña, who was twenty-five, hoped to find the answer, to set up a new Spanish colony, to make his fortune and win glory. However, any optimism he may have felt as the coast of Peru dipped below the horizon would have been misplaced. Although Magellan had managed to cross the Pacific from east to west in 1520–1, he had been killed in fighting with local people after reaching the Philippines, and only four out of the forty-four men who sailed with him aboard his small flagship had returned safely to Spain.2 This first, epic circumnavigation was counted as a brilliant success, but other expeditions ended in oblivion.
The challenges Mendaña faced were many. Not only was it impossible to carry sufficient fresh food and water for a voyage that might well last several months, but sailing ships were also vulnerable to the stress of weather, and the discipline of their rough and uneducated crews could never be relied on. First encounters with native peoples were fraught with danger, even if both sides were keen to avoid conflict, not least because cultural and linguistic differences made communication so difficult. If the Europeans brought with them infectious diseases that were to devastate native populations, tropical diseases also posed a serious threat to the visitors. To venture into the unexplored wastes of the Pacific was therefore to risk shipwreck, mutiny, warfare, disease, thirst, hunger and, most insidious of all, malnutrition.
After a passage of eighty days Mendaña’s two ships at last reached the ‘Western Islands’ in February 1568. Thinking at first that they had indeed found the legendary southern continent, Mendaña and his men explored the high, jungle-clad island on which they first landed and soon realized their mistake. They named it Santa Isabel, because they had sailed from Peru on that saint’s feast day, and went on to visit the neighbouring islands, which they called Guadalcanal, Malaita and San Cristóbal. Though a chief had greeted the Spanish visitors warmly on their first arrival, the natives could not satisfy their pressing demands for food; Mendaña had difficulty controlling his men – and blood, mostly native, soon flowed.
In August a disappointed Mendaña set sail from San Cristóbal. Having barely survived a hurricane, Mendaña and his officers had no idea where they were, how far they had travelled or when they might again reach land. Their few navigational tools would have included astrolabes and quadrants for determining latitude, magnetic compasses to steer by, hour-glasses for measuring short intervals of time, and lead-lines for sounding the depth in shallow water. But they had no proper charts and – crucially – no reliable means of judging how much progress they had made either to the east or to the west: only by estimating the ship’s speed through the water could the pilots assess how far they had travelled. This was a deeply unreliable method.
The agonizingly long return journey took Mendaña in a wide circuit across the North Pacific to reach the coast of Baja California in December 1568. He and his crew were reduced to a daily allowance of 6 ounces of rotten biscuit and half a pint of stinking water. Scurvy swelled their gums until they covered their teeth, they were racked by fever and many went blind. Every day they had to throw overboard another corpse. It was not until the following September that Mendaña finally reached Peru. He had found no riches, no continent, had made not a single convert and had failed to establish a colony, but his extraordinary voyage was to become a legend. Though he had been obliged to mortgage his property to get his ship repaired in Mexico, rumours spread that he had come home laden with gold and silver. The islands he had discovered were soon known by the name of the fabulously rich king of the Old Testament: Solomon.3 The longitude that he assigned to the Solomon Islands was so wildly inaccurate that subsequent explorers repeatedly failed to find them and eventually began to doubt their existence.4 It was to be 200 years before any European set foot on the Solomons again.
Mendaña himself failed to find the islands he had discovered when he mounted another, completely disastrous transpacific expedition in 1595, accompanied by Pedro Fernández de Quirós as chief pilot. He died in the Santa Cruz Islands – pathetically close to his goal – and Quirós eventually brought the disappointed survivors home to Peru via Manila after ‘incredible hardships and troubles’.5 Later generations of mariners and cartographers, deprived of detailed information about these voyages by the secretive Spanish authorities, struggled to make sense of Mendaña’s claims, and the Solomon Islands shifted giddily about the Pacific, varying in longitude by thousands of miles and even in latitude from 7 degrees to 19 degrees South. In 1768, within the space of a few months, two European mariners – Carteret and Bougainville – passed among the Solomons again, but without even realizing that they were following in Mendaña’s wake.6 They were soon followed by a French trader, Jean de Surville (died 1770), who visited the islands in 1769. Having closely investigated the accounts of these voyagers, and compared them to the descriptions that Mendaña had given, Jean-Nicolas Buache de Neuville (1741–1825)7 understood that the Solomon Islands had at last been rediscovered, though his arguments were not immediately accepted. His fellow countryman La Pérouse was to lose his life in trying to confirm his theory. Rear Admiral Joseph-Antoine Bruny d’Entrecasteaux finally settled the matter when searching for La Pérouse in the 1790s. He recognized many of the islands that Mendaña had described and decently restored to them the Spanish names that had been bestowed on them so long before.
The finding of the Solomon Islands, their subsequent ‘disappearance’ and eventual rediscovery perfectly illustrate the difficulties that confronted transoceanic navigators of the early modern age. It would be easy to multiply examples of this kind, which reveal the intimate, reciprocal dependence of navigation and hydrography – a recurrent theme of this book. The point is a simple one, but easily overlooked. To find the way safely, a mariner needs a chart that accurately records the positions of all that is navigationally significant – from the outlines of the major landmasses to the precise locations of tiny, uninhabited shoals on which a ship could founder. To make such charts, however, the hydrographer must first know the exact positions of everything that is to appear on them. Hydrography serves navigation, but only if nourished first by the fruits of navigation.
Two hundred and fifty years ago it was not just the location of the Solomon Islands that lay in doubt. Though it is hard for us to imagine such a state of affairs, the shapes of whole continents then remained largely unknown, and accurate charts – even of European waters – did not exist. The main reason for this state of ignorance was the imperfection of the art of celestial navigation and in particular the impossibility of determining longitude with any precision on board ship. In 1714 an Act of Parliament was passed in Great Britain designed to encourage the development of a practical shipboard solution to this age-old problem. It was not the first such prize but it turned out to be the last. Within fifty years, and in the space of a single decade, two radically different solutions emerged, one mechanical and the other astronomical (see Chapter 6). The long-running and often ill-informed tussle between the advocates of these two methods has obscured the fact that both depended on a newly developed observational instrument: the sextant.8 Though its praises have seldom been sung, the sextant was to play a crucial part in shaping the modern world – both literally and figuratively.
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The sextant, like the anchor, is a familiar symbol of the maritime world, but to most people – including many sailors – its purpose is a mystery. One strand of my task is to sketch the developments in astronomy, mathematics and instrument-making that first permitted navigators to fix their position with its help. But I also wish to bring the sextant to life by examining some of the astonishing feats of the explorers who put this ingenious instrument to such good use in making the first accurate charts of the world’s oceans. The work of the pioneering marine surveyors of the late eighteenth and early nineteenth centuries – some of whom are almost forgotten – is another key strand. Because it is such a wide subject I have focused on those who worked in the Pacific, which