Magnusen nodded.
'Alone, if you don't mind.'
Magnusen stood up. 'The three-button mouse operates the three axes. Or you can—'
'I'm aware of how the program works.'
Magnusen left, closing the door to Island One behind her without another word. St. John sighed and settled into the now-vacant chair. Hatch turned to leave.
'I didn't mean for you to go,' St. John said. 'Just her. What a dreadful woman.' He shook his head. 'Have you seen this yet? It's remarkable, really.'
'No,' Hatch said, 'What is it?'
'The Water Pit and all its workings. Or rather, what's been mapped so far.'
Hatch leaned closer. What looked like a nonsensical jumble of multicolored lines was, he realized, a three- dimensional wireframe outline of the Pit, with depth gradations along one edge. St. John pressed a key and the whole complex began to move, the Pit and its retinue of side shafts and tunnels rotating slowly in the ghostly blackness of the computer screen.
'My God,' Hatch breathed. 'I had no idea it was so complex.'
'The mapping teams have been downloading their measurements into the computer twice a day. My job is to examine the Pit's architecture for any historical parallels. If I can find similarities to other constructions of the time, even other works of Macallan's, it may help us figure out what booby traps remain and how they can be defused. But I'm having a difficult time. It's hard not to get swept away by the complexity. And despite what I said a minute ago, I have only the faintest conception of how this contraption works. But I'd rather swing from a gibbet than ask that woman for help.'
He struck a few keys. 'Let's see if we can clear away everything but the original works.' Most of the colored lines disappeared, leaving only red. Now the diagram made more sense to Hatch: He could clearly see the big central shaft plunging into the earth. At the hundred-foot level, a tunnel led to a large room: the vault where Wopner was killed. Deeper, near the bottom of the Pit, six smaller tunnels angled away like the fingers of a hand; directly above, a large tunnel climbed sharply to the surface. There was another narrow tunnel angling away from the bottom, plus a small array of side workings.
St. John pointed to the lower set. 'Those are the six flood tunnels?'
'Six?'
'Yes. The five we found, plus one devilish tunnel that didn't expel any dye during the test. Magnusen said something about a clever hydrological backflow system. I didn't understand half of it, to be honest.' He frowned. 'Hmm. That tunnel right above with the gentle slope is the Boston Shaft, which was built much later. It shouldn't be displayed as part of the original works.' A few more keystrokes, and the offending tunnel disappeared from the screen.
St. John glanced quickly at Hatch, then looked back at the screen again. 'Now, this tunnel, the one that angles toward the shore—' He swallowed. 'It isn't part of the central Pit, and it won't be fully explored for some time yet. At first, I thought it was the original back door to the Pit. But it seems to come to a waterproofed dead end about halfway to the shore. Perhaps it's somehow linked to the booby trap that your brother...' His voice trailed off awkwardly.
'I understand,' Hatch managed to say, his own voice sounding dry and unnaturally thin to his ears. He took a deep breath. 'They're making every effort to explore it, correct?'
'Of course.' St. John stared at the computer screen. 'You know, until three days ago I admired Macallan enormously. Now I feel very differently. His design was brilliant, and I can't blame him for wanting his revenge on the pirate who abducted him. But he knew perfectly well this Pit could just as easily kill the innocent as the guilty.'
He began rotating the structure again. 'Of course, the historian in me would say Macallan had every reason to believe Ockham would live long enough to come back and spring the trap himself. But the Pit was designed to live on and on, guarding the treasure long after Ockham died trying to get it out.'
He punched another key, and the diagram lit up with a forest of green lines. 'Here you can see all the bracing and cribbing in the main Pit. Four hundred thousand board feet of heart-of-oak. Enough to build two frigates. The structure was engineered to last hundreds of years. Why do you suppose Macallan had to build his engine of death so strong? Now, if you rotate it this way—' He poked another button, then another and another. 'Damn,' he muttered as the structure began to whirl quickly around the screen.
'Hey, you're going to burn out the video RAM if you twirl that thing any faster!' Rankin, the geologist, stood in the doorway, his bearlike form blotting out the hazy morning light. His blond beard was parted in a lopsided smile.
'Step away from that before you break it,' he joked, closing the door and coming toward the screen. Taking St. John's seat, he tapped a couple of keys and the image obediently stopped spinning, standing still on the screen as if at attention. 'Anything yet?' he asked the historian.
St. John shook his head. 'It's hard to see any obvious patterns. I can see parallels here and there to some of Macallan's hydraulic structures, but that's about it.'
'Let's turn it around the Z-axis at five revolutions per minute. See if it inspires us.' Rankin hit a few keys and the structure on the screen began rotating again. He settled back in his chair, threw his arms behind his head, and glanced at Hatch. 'It's pretty amazing, man. Seems your old architect may have had some help with his digging, in a manner of speaking.'
'What kind of help, exactly?'
Rankin winked. 'From Mother Nature. The latest tomographic readings show that much of the original Pit was already in place when the pirates arrived. In natural form, I mean. A huge vertical crack in the bedrock. That might even have been the reason Ockham chose this island.'
'I'm not sure I understand.'
'There's a huge amount of faulting and displacement in the metamorphic rock underlying the island.'
