He shakes so badly with the ague that he can hardly read what he has written, but he carries on working through night, lighting each fresh candle from the stump of the last, his shivering body and wretched soul fueled by warm cider laced with butter. The innkeeper-cum-fisherman has covered the fire and rolled out his bed and sleeps on the rushes below with four greyhounds, the dogs’ three-quarter-closed eyes occasionally catching the firelight, soft and companionable. The wind is in the chimney and the fisherman whimpers, dreaming perhaps of the perils of the sea, while Dee tries to make sense of the document retrieved from the sacristy of the Abbey of Mont Saint-Michel, and of the numbers Isobel Cochet gave him before she died.
He owes her that, at least.
The chart is as she described: a series of circles, some infilled with letters and numbers. Dee had recognized it as being an unusual astrological chart, round rather than square, with its twelve houses of the heavens, and true node signs. Some of the chart is filled in with signs that Dee recognizes—Leo, Libra, Capricorn, as well as the familiar exaltation and triplicity points and so on, though for some reason Neptune in Aquarius is emboldened in red—but certain key pieces of information are missing.
Obviously these must be the numbers that Isobel Cochet gave him before she died. Once those are entered, then a skillful caster might read the chart backward: to take from what is written here not, as would be usual, the chances of a man’s success and happiness, and so on, but to find the place of birth of the man whose chart this might be.
When he first divined this was the chart’s secret, Dee was gripped by intellectual excitement. He believed that he might imminently gain knowledge of the whereabouts of the mouth of the Straits of Anian.
But it has not been as easy as that.
The numbers—they do not make sense.
He has tried every combination, in every house of the zodiac, and so far has drawn latitudes that range from the very farthest south any man has yet dared to sail, to those very far north, which, if he can believe it, would put the mouth of the strait somewhere very far to the north, where the ice is so extensive and the cold so deep that no man could suffer it. Where Admiral Willoughby and his expedition had vanished, eaten up by the ice.
This cannot be the opening of the Straits of Anian.
Admiral DaSilva cannot have sailed so far north and returned alive.
It is just not possible.
After trying every permutation of the numbers in the chart with no more plausible results, he began to wonder if DaSilva has further encrypted the numbers. So he has tried to decrypt them, subjecting them to every process he knows—which is every one yet devised by man, from the simple letter frequency analysis technique as described by the Arab mathematician Alkindus, up to the tabula recta system devised by Johannes Trithemius, as well as various polyalphabetic ciphers as have been devised by Blaise de Vigenère in Paris and Leon Alberti in Genoa—but with numbers, and so very few of them, it is impossible to be certain.
And even then, each time he puts his decryptions into the chart and attempts to interpret the result in this strange backward fashion, he still comes up with nothing that is remotely plausible, and he is left wondering if the numbers are either in a cipher of which he has never heard tell—which he cannot believe for surely Baltazar DaSilva is a navigator, not a cryptographer?—or, worse, that Isobel Cochet got the numbers wrong.
And so he sits thinking about this, reliving those last terrible moments on the sands below Mont Saint-Michel, and the more he does so, the more certain he is that she was not wrong. She did not make a mistake. She repeated the numbers perfectly. Twice.
Nor did he make a mistake either. He has a mnemonic system he developed with Petrus Ramus—may God assoil his soul—and even now, days after the event, he is able to rattle the numbers off just as if he had heard them but moments ago.
And yet… and yet. He holds Mercator’s globe in his palm and he studies the lines of latitude so carefully scribed through its continents, so much of it still terra incognita, and at the top, almost at the pole, is the line of latitude that DaSilva has identified.
Can it be DaSilva who has gotten it wrong?
That is possible. But very improbable. An admiral’s logbook is a sacred thing. This page will have been a fair copy of a fair copy, held almost as a reliquary on board the ship.
So where was the mistake introduced?
On he goes, around and around, a dog chasing its own tail.
He will try one last process, he thinks, of which he very recently heard tell by a Neapolitan (the same who showed him the secret mix of plant dyes and alum needed to write on the shell of an egg, so that when it is boiled, the message becomes invisible on the outside, but transfers itself to the hard-boiled yolk). It is a form of the digraphic substitution cipher, applied to the numbers once they are rotated by seven, the number of the chart’s emboldened Neptune, first into Latin, and then into Hebrew.
Dee works solidly for a candle’s length, and at the end of it, it still makes no sense, and he is about to give up, when he decides to rotate the letters once more, again by seven, this time back into Latin, which he will turn back into numbers to put into the chart.
Before he can complete this final step, though, before he can
