The serving-girl, Bridget, had entered the room with a pot of tea whose fragrant steam was curling through the air. I was gnawing at my lower lip as I perched in the chair, studying the rows of atlases overhead. I could see Martin Waldseemüller's Universalis Cosmographia and several editions of Ptolemy's Geography, including the one by Gerardus Mercator. Alethea, catching my gaze, set down her cup and pushed back her chair.
'A number of these maps and atlases are extremely rare,' she said, rising to her feet. 'Some are among the rarest and most valuable items in the entire collection. This one, for example.' She was standing on tiptoe, reaching for one of the volumes, which she then proceeded to flump on to the table between us, rattling our teacups. I was startled to see the water-damaged copy of Ortelius, the Theatrum orbis terrarum, the same volume I had inspected in the laboratory: the one from which I had cut the cipher. 'Do you know it?'
'I sell copies of it, yes,' I replied as she opened the buckram cover. I cocked my head and tried to read the colophon. 'This is the Prague edition?'
'Yes, published in the year 1600.' She began riffling through the crimped pages. 'It's extremely rare. Only a few copies were ever printed. Ortelius had travelled to Bohemia at the invitation of the Emperor Rudolf. Unfortunately he died in 1598, soon after his arrival in Prague. Some of the physicians claimed that he died of an ulcer of the kidneys, which Hippocrates tells us is nearly always fatal in old men.' Slowly she turned over one of the pages. 'Others believed that the great Ortelius was poisoned.'
'Is that so?' I glanced at the atlas, recalling the rumours mentioned by Mr. Barnacle. The volume was now open at a sheet displaying the legend 'MARE PACIFICUM'-the very point at which I had discovered the cipher. 'Why should that have been?' I was trying to remember what Mr. Barnacle had said about voyages through the islands in the high latitudes. 'Because of the new method of map projection?'
She shook her head. 'No such method of projection has yet been perfected. How those rumours started I have no idea, unless they were the invention of whoever murdered Ortelius.'
'So Ortelius was murdered?'
She nodded. 'After his death the plates from which the maps were engraved disappeared from the printshop. Or I should say one plate disappeared, that from which this particular map was engraved.' She tapped the rippled sheet with her forefinger, 'You see, the map of the New World in the Prague edition of the Theatrum orbis terrarum is different from those in any of the others.'
I was still scanning the page, wondering if I ought to believe her account any more than Mr. Barnacle's. There was an elaborate cartouche-'AMERICAE SIVE NOVI ORBIS, NOVA DESCRIPTIO'-and a representation of the Pacific Ocean, complete illustrations of islands and fully rigged galleons. Everything on the sheet looked precisely the same as on those dreamy afternoons at Molitor & Barnacle, including the scales of latitude and longitude.
'Map making is a speculative art,' she said as she turned the atlas 180 degrees on the table to face me. Again she tapped it with her finger, this time just above the cartouche. 'Look here. What do you see?'
Beneath her index finger I could make out a cluster of a half-dozen islands and the legend 'Insulæ Salomonis'. I shrugged and looked up. 'The Solomon Islands,' I replied cautiously.
'Precisely. But no one knows if the Solomon Islands are actually found at the spot where Ortelius places them. Indeed, no one even knows if they truly exist or if they were only the fantasy of Alvaro de Mendaña, who claimed to have sighted them in the year 1568. He named them the Islas de Solomón because he believed them to be the islands on which King Solomon mined the gold for his Temple in Jerusalem. But King Solomon must have been a better navigator than Mendaña, because the Spaniard never again found the islands. He made a second voyage in search of them in 1595, but with no luck. His pilot, Quirós, made a third in 1606, and many have searched since then. But they appear to have sunk into the ocean one and all, like Atlantis. They remain as elusive as Terra australis incognita, which Mendaña and Quirós had also hoped to discover.' Her finger had drifted down the page before stopping to the left of the cartouche, where I could read the inscription 'TERRA AUSTRALIS'. The rest of the space, a large continent whose coast ran down the map's two-hundredth meridian, was blank and featureless. 'Another mythical land portrayed by Ortelius.'
'The continent described in Ptolemy's Geography,' I said, wondering what such legendary islands had to do with Galileo or the libraries of Prague.
'And in Arab and Chinese documents as well. Rumours of its existence have circulated for centuries. The Spaniards sent numerous expeditions to discover it, all in vain, though in 1606 Quirós discovered a landmass, in fact only islands, that he named Australia del Espiríto Santo. Afterwards it was sought by the Dutch, likewise in vain until a number of their ships bound for Java were blown off course and made landfalls along the coast of an enormous island guarded by coral reefs. Twenty years later some of their ships explored a coastline that stretches from the tenth parallel of latitude below the equator to the thirty-fourth. So it now appears that Terra australis incognita is something more than a myth. And if Terra australis incognita exists, then who is to say that the Islas de Solomón do not also exist?' She leaned forward and with her forefinger traced a path across the Pacific to the right-hand side of the sheet. 'Look here. You'll see that the Prague edition includes an interesting variant.'
I peered closely at the page. The light from the rain-streaked window was so dim I had to strain my eyes to see its image. But there, some thirty or forty degrees of longitude west of Peru, a dozen parallels south of the equator, in the middle of Ortelius's vast Mare Pacificum, was a tiny rectangular island marked 'Manoa'. This particular detail was not included on any of Mr. Smallpace's editions, of that I was certain.
'But I thought Manoa was in Guiana or Venezuela.'
'As did everyone else. But to Ortelius it was an island in the Pacific Ocean, that great cavity left in the earth when the moon broke free. It would be found to the west of Peru and to the east of the fabled Islas de Solomón, on the 280th meridian east of the Canary Islands, which is what Ortelius, following Ptolemy, uses as his prime meridian. Or that, at least, is where Manoa is placed in the Prague edition of 1600.' She rose to her feet and carefully slid the volume back on to its shelf. 'You see, none of the other editions of Ortelius portrays Manoa,' she explained as she returned to her chair, 'either in the Pacific or anywhere else. That is what makes the Prague edition unique. And that, of course, is what Sir Ambrose found so intriguing.'
'But there were other maps of Manoa,' I protested, remembering Raleigh's map, engraved in Amsterdam by Hondius, that I used to explore with my fingers as I crouched between the shelves in Mr. Molitor's shop.
'Yes, but most were crude affairs. Manoa was located all over the continent. But after Mercator it became possible for navigators to make use of latitude and longitude when plotting their courses. They could steer a straight course over a long distance without continually adjusting their compass readings. All that was needed was a ruler, a divider and a compass. Mere child's play.'
'Yes,' I nodded. 'Except for the minor detail that no one knows how to find the longitude at sea.'
'Yes, there is the rub,' she replied, returning to the shelf. 'Finding latitude is easy enough, even below the equator where the Pole Star cannot be sighted. One merely finds the sun's altitude at noon by means of a sundial or suchlike. But longitude is as difficult a proposition as squaring the circle.'