Mindful of the police search that had doubtless already begun, they headed back to the motoscafo at a quickened pace. Bravo unwrapped the package. Inside was a small silver Greek cross. Wrapped around it, like a beehive or a wasp's nest, was a skein of red threads.
'What do you make of it?' Rule said, peering over his shoulder.
Bravo shook his head.
They reached the boat without incident. The tarp was in the same position in which Rule had left it. Quickly, they stowed it and cast off. Rule handed Bravo the flashlight. While he maneuvered the motoscafo away from Lazzaretto Vecchio, Bravo switched on the flashlight and holding the Greek cross in its beam unwound the short lengths of red string. There were twenty-four. The area on the body of the cross that was now revealed had three words etched into it. Bravo knew that this was a two-key fractionation system cipher. One of the most famous field ciphers, it had been employed by the German Army during World War I. The first two words were the keys, the third word was the encrypted text. He opened his father's notebook to a blank page and began to work.
The cipher system was based on the ADFGVX cipher, which used a 6?6 matrix to substitute-encrypt the twenty-six letters of the alphabet and ten digits into pairs of the symbols A, D, F, G, V and X. The resulting biliteral cipher was only an intermediate cipher, however. It was then written into a rectangular matrix and transposed to produce the final cipher.
What Bravo came up with was a single word: sarcophagus.
'Where are we headed now?' Rule said at length. 'Do you know?'
'Back to Venice,' Bravo said, pocketing the notebook and cross. The red threads he dropped into the dark, ruffled water as if they were the last vestiges of his father, who had been here and, by this gesture, was here again.
Dawn was extending its long pearly fingers across the flat expanse of the lagoon. For a few moments they were alone on the water. The oblique light turned the surface into sheet metal through which their boat cut cleanly, like a honed knife. Birds called and circled, roused from the sleep by the dawn and the hunger in their stomachs. They swooped and called to one another as they hunted, submerging themselves briefly to snatch a fish between curved bills.
There were other hunters on the lagoon. As the motoscafo rounded the end of the Lido, they saw the police launch, and immediately Rule cut his speed.
Bravo came up alongside him. 'What are you doing?'
'You'll see.'
Rule had not changed course. In fact, so far as Bravo could tell, he was pointing the bow of the boat directly at the police launch. And now, though Bravo knew that the flatness of the lagoon in certain light could fool the eye and even create mirages, just like in the desert, he was certain that the police launch, having spotted them, had put on speed. He could see the bow lift and the new charge of foam fountaining behind it.
'Uncle Tony-'
'Have faith, Bravo. Have faith.'
The police launch rocketed toward them, its speed and noise scattering what was left of the breakfasting birds. Bravo could make out the men aboard, though not yet their individual faces or their uniforms.
He heard a sound then, like the noise wind makes when it catches the rigging of a boat and tautens all its sails. But of course the motorboat had neither rigging nor sails, and then he realized that it was Uncle Tony, who was humming happily to himself. He was in his element, commanding a fast boat, about to go head to head, as it were, with adversaries. This is what he lives for, Bravo thought This is why the Voire Dei drew him like aflame.
The police launch was closing at what Bravo considered alarming speed.
Rule stopped his humming long enough to say, 'Hold on,' out of the side of his mouth.
Bravo clutched the railing with both hands as Rule shoved the throttle forward and the motoscafo leapt forward. He had an instant's glimpse of the astonishment in the eyes of the policemen aboard the other vessel as the motoscafo suddenly bore down on them, and he felt a shock go through him. Then Rule had turned the wheel hard to starboard. He had threaded the needle with an expert's hand, and the motoscafo veered off with a breathless rush, its port side lifted as it slashed through the water, creating a wave that swept aboard the police launch like a shipload of pirates.
Then they were away, headed northeast, in the general direction of Venice but more closely aimed at another islet whose northern flank presented itself to them to starboard. Bravo, glancing behind them, saw the swamped police launch swinging around, and with a roar it put on all speed to follow them.
'There's something about that boat,' Rule said. 'It's longer and lower in the water than the launches used by the Venetian police.'
'You're right. I recognized a Guardian. That isn't a police launch at all.'
Rule nodded. 'Zorzi's picked up our trail.'
The islet was coming up fast on their right. It was deserted, full of reeds and birds and the clean-sweet smell of decay. They had to be careful now because the water was shallow enough in spots to ground the boats. Long sandbars rose here from the depths of the lagoon to provide feeding grounds for birds as well as natural platforms for clamming.
The sun was fully above the horizon now, looking red and bloated, as if ill with a fever. The light, stronger, shot across the water in wavering lines, making the islet seem farther away than it was. The air was warming quickly, creating a period of disorienting perspectives and bewitching mirages.
'We can't let him stop us,' Bravo said, leaning in so he could speak over the engine's heightened bellow. 'You've got to get me to Venice.'
Rule swung the wheel hard over. 'Don't worry,' he said grimly. 'I mean to take Zorzi out of the picture once and for all.'
If Paolo Zorzi were any other kind of man he would have blown a blood vessel by now, but he hadn't worked his way into the upper echelon of the Gnostic Observatines by being impatient or impetuous. 'All things in their season' was his unspoken motto, and even in this chaotic moment when the tenuous future hung in the balance, he remained deathly calm. He neither cursed himself nor his crew for having failed to respond adequately to Anthony Rule's kamikazelike tactic, but he did resolve not to allow Rule to surprise them again.
Now, as they once again raced after Rule, he took the wheel himself. Instead of following directly in Rule's wake, he quartered in from the port side, effectively pinning Rule into the shallow passage of water between his oncoming motoscafo and the northernmost corner of the islet up ahead. He grinned as he came on. With each second that passed Rule's options were becoming more limited. Soon, he'd be out of options altogether.
'You see what he's trying to do,' Bravo said. 'Pin us into grounding ourselves on the shoals close to the islet.'
'In this as in all things, he is bound to be disappointed.' Rule's voice was low and fierce. The wind had got between his open lips, pulling his cheeks back from his bared teeth.
'But you're heading right for the shallows,' Bravo said.
Rule said, 'Zorzi will be well pleased for the same reason.'
In the deceptive light, he could not make out the distinctions in the color of the lagoon that in late morning through late afternoon mariners used to differentiate the deepwater channels from the shoals that could wreck them. Charts were all well and good elsewhere, but the combination of the changing light and the treacherous tides often rendered the maps useless in all but the few major deepwater passages.
Ahead, Bravo could see the islet coming up fast-the sea fields of quivering reeds, the glistening tide pools, a dark wave, the rising and falling of the birds over their nests, and just beyond, like a series of wavecrests, a pair of barene, salt flats that were actually sandbars, pale as a woman's throat, the smaller one closer. On the one farther from them a dozen or so men stooped, their feet and ankles hidden beneath the water as they went about their morning's work, gathering clams that would be consumed that afternoon and evening in Venice's restaurants.
Rule kept glancing over his left shoulder as if worried about the police launch vectoring in off the port quarter. He kept edging in closer and closer to the islet. The launch, having maintained full speed, had gained on them. Apparently, this was precisely what Rule wanted, for he made no effort to push his own throttle forward. This would be consistent with a captain concerned with grounding his boat.
The police launch was now-by Bravo's admittedly inaccurate estimation-only three boat-lengths behind
