“I know that look,” Professor said, his tone grim. “What’s wrong?”
“The entrance chamber. It’s completely flooded. And I’ll save you the trouble of asking.” She sagged in defeat. “I didn’t see that.”
TWENTY-FIVE
Shah was incredulous. “Flooded? In Arizona? How is that possible?”
Jade squeezed her eyes shut, recalling the vision from the Hypogeum. She had seen a round chamber at the end of the passage, and the three circles that appeared to be linked but really weren’t. There had not been any water. She related exactly what she had seen to Professor.
“I think…” She hesitated. “Could this be how the timelock mechanism works?”
Professor nodded in understanding. “That makes sense. Water clocks have been around a long time. The Chinese may have created water clocks as far back as six thousand years ago. Water flows at a constant rate. Even though this is the desert, there’s plenty of rainfall in the monsoon season. Rainfall on the top of the rock seeps down and recharges the reservoir. Throw in a sufficiently complex clockwork mechanism, and you could make a water clock that keeps time over very long periods.”
“So we have to wait until it drains?” Shah said. “We just come back in… Ha! We don’t even know how long to wait. Wonderful.”
“We could probably pump the water out,” Professor said, though his tone suggested that he considered this a measure of last resort rather than the best way forward. “I doubt very much we could pull that off without attracting a lot of attention.”
“If the chamber was dry, we’d be able to unlock the vault,” Jade said, thinking aloud. “Those rings are the key. They’re like a… a pass code or the combination to a safe. Maybe we don’t have to actually drain the chamber to open it.”
Professor’s eyebrows drew together. “SCUBA?”
“Why not?”
“Well, for starters, we don’t have any gear. We’d probably have to drive to Phoenix to find a dive shop, which we wouldn’t be able to do until tomorrow. And someone is bound to ask why we’re hauling gas cylinders and wetsuits up the trail. But aside from that, the biggest problem I see is hydraulic pressure. Water is heavy. About eight pounds to the gallon. I don’t know how big this chamber is, but let’s say it’s about the same size as a backyard swimming pool — roughly ten thousand gallons. That’s eighty thousand pounds. Forty tons, pressing against that locked door. I’m not sure you’d even be able to open it, but if you could, the results could be…well, unpredictable to say the least.”
Jade managed a wan smile. “We can handle unpredictable.”
Professor threw her a withering glance.
“How about this,” Jade went on. “I’ll swim into the chamber and try to get a better look at it. Maybe then we’ll have a better idea of how to get it open.”
“You want to free dive in a cave? You want to swim into a dark cave, have a looksee, and then find your way back out, all on one breath? Cave diving is insanely dangerous under the best of circumstances. Without gear? No. It’s suicide.”
“I can hold my breath for two minutes. That passage drops right into the cave, so I could spend a whole minute looking around, and have plenty of time to get back out. We can pull the rope up and I’ll tie off. That way I can’t get lost and if anything goes wrong, you can pull me back.”
Professor started to say something, but Jade cut him off. “I know, you think you’re the stronger swimmer, so you should go. But I’ve seen that chamber in my vision. I know I can figure out how to open it.”
Professor shook his head. “I wasn’t going to say that. What would be the point? Once you get an idea in your head, there’s no reasoning with you. I was going to say that maybe we can make some field expedient swim goggles so you can at least see what you’re doing.”
He took a half-filled water bottle from his back pocket, drained the contents in a long swig, and then held the empty plastic container up. “Should be able to do something with his.”
“Oh. Why didn’t you just say so?”
“Get the rope,” he said. “And give me your knife. I lost mine in Australia. Once more thing that trip cost me.”
Jade passed over her Swiss Army knife and then went to the edge of the cave mouth to gather up the belaying line. She knotted the end to her climbing harness and then threw the rest of the coil onto her shoulder. Professor, meanwhile sliced out two oval shaped pieces from the bottoms of two plastic bottles. He pressed them to his eyes and scrunched up his face to hold them in place.
“They’ll be leaky,” he said, removing them and handing them to her, “but they should be good for thirty seconds or so.”
Jade tried the makeshift lenses. The edges were sharp, digging into her skin, but the discomfort was a small price to pay for being able to see clearly underwater.
Professor wasn’t finished however. He took out the sketch of the circles and began drawing something new beneath them. “Borromean Rings are an impossibility using true circles. An optical illusion like something from Escher. But if you use slightly elliptical circles positioned at angles in three dimensions, the perspective changes make them look like circles when viewed top down. Sort of like this.”
He held up the new sketch.
“Look for something like this. Then you’ll know you’re on the right track.”
“You’re kidding. Those are the same?”
He nodded. “More or less. This is only one possible solution of course. But keep your eyes open for it.”
She squinted through the eye cups. “If I open my eyes too wide, these things will fall out, but I’ll do my best.” She handed him the climbing rope. “I tug on this as soon as I’m in the chamber. After that, if I give two sharp tugs, pull me back.”
“And if you aren’t out in sixty seconds, I’ll drag you out anyway.”
“Make it ninety. I want to be able to take my time in there.”
“Fine, but not a second longer.”
“Wish me luck.” With that, Jade turned and headed back up the narrow passage. It was cramped. Professor would probably be able to scrape through, but barely. During her earlier exploration, she had been forced to crawl backward since there was no room to turn around at the far end; merely an opening about a foot above the water’s surface.
She reached the opening and thrust her flashlight into the submerged chamber. The waterproof light revealed an enormous murky void and not much else. The water was chilly on her skin and immersion in it would be bracing, but not enough to cause hypothermia in the minute and a half she would be in it. She looked over her shoulder, back down the length of the passage but was unable to see Professor or Shah. She took several quick breaths, hyperventilating to oxygenate her blood, and then, with one hand holding the eye cups in place, she plunged forward, headfirst into the water.
The slap of cold was about what she expected and she had to fight the urge to let all her air out in a howl of dismay. Her natural buoyancy immediately tried to bring her back to the surface, and water began infiltrating the makeshift goggles, but in that first moment, she got her first real look at the entrance to the vault.
Being in the chamber was, Jade thought, like swimming in a municipal water tank. It was about twenty feet across and perfectly spherical, save for the strange and seemingly haphazard gaps and protrusions that ruined the otherwise perfect symmetry. As she studied the relief, looking for some kind of recognizable pattern, Jade felt something tugging at her waist.
Crap. I forgot. She found the safety line with the hand that held the flashlight and gave it a single hard pull, hoping that Professor would not misinterpret the signal and drag her out. She had already been in the water for a good fifteen seconds, and something told her she had overestimated her ability to hold her breath in the chilly conditions. When the rope did not go taut again, she assumed the message had been correctly received, and returned her attention to the walls of the chamber.