"Now this last remnant has become Alexander's headstone," Rachel said.

"I think all all of this is a testament to Alexander," her uncle said. "And to the science and knowledge he helped foster. It was at the Library of Alexandria that Euclid discovered the rules of geometry. All around here are triangles, pyramids, circles." of this is a testament to Alexander," her uncle said. "And to the science and knowledge he helped foster. It was at the Library of Alexandria that Euclid discovered the rules of geometry. All around here are triangles, pyramids, circles."

Uncle Vigor then pointed up and down. "The reflected sphere split by water harkens to Eratosthenes, who at Alexandria calculated the diameter of the Earth. Even the water here...it must be fed through small channels to keep this pool full. It was at the library that Archimedes designed the first screw-shaped water pump, which is still in use today."

Her uncle shook his head at the wonder. "All of this is a monument to Alexander and the lost Library of Alexandria."

That reminded Rachel of something. "Weren't there supposed to be books down here? Didn't Septimus bury the most important scrolls of the library down here?"

Vigor searched around. "They must have been cleared out after the quake. When the clues were planted here. The knowledge must've been taken and sent to whatever hidden vault we seek. We must be close."

Rachel heard the quaver in her uncle's voice. What else might they discover?

"But before we move on," Gray said, "we first must solve this riddle."

"No," Uncle Vigor said. "The riddle is not even exposed yet. Remember at St. Peter's. We must pa.s.s some test. Prove our knowledge, like the Dragon Court did with their understanding of magnetism. Only after that was the secret revealed."

"Then what are we supposed to do?" Gray asked.

Uncle Vigor stepped back, his eyes on the pyramid. "We have to activate this pyramid."

"And how do we go about doing that?" Gray asked.

Vigor turned to Gray. "I need some soda."

1:16 P P.M.

GRAY WAITED for Kat to ferry up the last of the cans of c.o.ke. They needed two more six-packs. "Does it matter if it's diet c.o.ke or regular?" Gray asked. for Kat to ferry up the last of the cans of c.o.ke. They needed two more six-packs. "Does it matter if it's diet c.o.ke or regular?" Gray asked.

"No," Vigor said. "I just need something acidic. Even citrus juice would work, or vinegar."

Gray glanced to Rachel. She just shook her head and shrugged.

"Would you care to explain now?" Gray asked.

"Remember how magnetism opened the first tomb," Vigor said. "We know that the ancients were well aware of magnetism. Lodestones were widely distributed and used. Chinese compa.s.ses date back to 200 B B.C. To move forward, we had to prove our understanding of magnetism. It even led us here. A magnetic marker left underwater."

Gray nodded.

"So another scientific wonder must be demonstrated here."

Vigor was interrupted by the arrival of Kat. She rose up into the entry pool, bearing aloft two more six-packs, making it a total of four.

"We're going to need Kat's help for a few minutes," Vigor said. "It'll take four people."

"How are things topside?" Gray asked Kat.

She shrugged. "Quiet. Monk fixed a radio glitch. That was the extent of any excitement."

"Let him know you'll be off the air for a couple minutes," Gray said, uneasy, but they needed whatever was hidden here.

Kat dunked under, pa.s.sing on the message. She then quickly climbed out and they all returned to Alexander's tomb.

Vigor waved for them to disperse. He pointed to a copper urn at the pool's edge. There were four of the pots. "Each of you take a six-pack of soda and take up a post by the jars."

They spread out.

"Care to tell us what we're doing?" Gray asked as he reached his copper jar.

Vigor nodded. "Demonstrating another scientific wonder. What we must show here is the knowledge of a force known even to the Greeks. They called it electrikus electrikus. A name for the static charge of a cloth rubbed over amber. They witnessed it in the form of lightning and along the masts of their sailing ships as Saint Elmo's fire."

"Electricity," Gray said.

Vigor nodded. "In 1938, a German archaeologist named Wilhelm Koenig discovered a number of curious clay jars in the National Museum of Iraq. They were only fifteen centimeters tall. They were attributed to the Persians, the homeland of our biblical Magi. The odd thing about the tiny jars was that they were plugged with asphalt, and from the top protruded a copper cylinder with an iron rod inside. The conformation was familiar to anyone with knowledge of voltaic sciences."

Gray frowned. "And for those not familiar?"

"The jars...they were the exact conformation of battery cells, even earning the name 'the Baghdad Batteries.'"

Gray shook his head. "Ancient batteries?"

"Both General Electric and Science Digest Science Digest magazine in 1957 replicated these jars. They primed them with vinegar, and the jars gave off significant volts of electricity." magazine in 1957 replicated these jars. They primed them with vinegar, and the jars gave off significant volts of electricity."

Gray stared down at the jars at his feet, remembering the monsignor's request for soda, another acidic solution. He noted the iron rod sticking out of the top of the solid copper jar. "Are you saying these are batteries? Ancient Duracell Coppertops?"

He stared at the pool. If the monsignor was correct, Gray understood now why jars were resting in the seawater pool. Whatever shock was generated by the batteries would flow through the water to the pyramid.

"Why don't we just jump-start the pyramid?" Kat said. "Bring down a marine battery from the boat?"

Vigor shook his head. "I think the activation is tied to the amount of current and the position of the batteries. When it comes to the magnitude of power in these superconductors-especially one this size-I think we should stick to the original design."

Gray agreed. He remembered the quake and the destruction inside the basilica. That had been with only a single cylinder of m-state powder. He eyed the giant pyramid and knew they'd better heed the monsignor's recommendation.

"So what do we do?" Gray asked.

Vigor popped the top to one of his sodas. "On my count, we fill up the empty batteries." He stared around the group. "Oh, and I suggest we stand well back."

1:20 P P.M.

MONK SAT behind the boat's wheel, tapping an empty can of soda on the starboard rail. He was tired of all this waiting. Maybe scuba diving wasn't so bad. The water looked inviting as the day's heat rose. behind the boat's wheel, tapping an empty can of soda on the starboard rail. He was tired of all this waiting. Maybe scuba diving wasn't so bad. The water looked inviting as the day's heat rose.

The loud rumble of an engine drew a glance across the harbor.

The hydrofoil, which had seemed to drop anchor, was on the move again. He listened to the engine throttle up. There seemed to be a bit of commotion on the deck.

He reached for his binoculars. Better safe than sorry.

As he raised the binoculars, he glanced to the monitor of the Aqua-Vu camera. The tunnel continued to be unmanned.

What was taking Kat so long?

1:21 P P.M.

GRAY EMPTIED his third can into the cylinder core of his jar. Soon c.o.ke was bubbling down the copper side of the battery. Full. his third can into the cylinder core of his jar. Soon c.o.ke was bubbling down the copper side of the battery. Full.

He stood up and took the last swig from his soda can.

Ugh...diet...

The others finished about the same time, standing and moving back.

A bit of carbonation frothed out the tops of all the cylinders. Nothing else happened. Maybe they had done it wrong, or the soda wouldn't work-or even more likely, the monsignor's idea was simply full of c.r.a.p.

Then a spark danced from the tip of the iron rod of Gray's jar and cascaded down the copper surface to fizzle out in the seawater.

Similar weak pyrotechnics drizzled from the other batteries.

"It may take a few minutes for the batteries to build and discharge a proper voltage." Vigor's voice had lost its confident edge.

Gray frowned. "I don't think this is going to-"

Simultaneously from all four batteries, brilliant arcs of electricity crackled through the water, fire in the deep. They struck the four sides of the pyramid.

"Back against the wall!" Gray yelled.

His warning was not needed. A blast of force thumped outward from the pyramid, throwing him bodily against the wall. The pressure made it feel like Gray was on his back, the drum-shaped chamber circling over him, the pyramid above him, a topsy-turvy amus.e.m.e.nt ride.

Yet Gray knew what held him.

A Meissner field, a force that could levitate tombs.

Then the true fireworks began.

From all surfaces of the pyramid, crackling bursts of lightning shattered to the ceiling, seeming to strike the silver stars imbedded there. Jolts also lanced into the pool, as if attempting to attack the reflected stars in the water.

Gray felt the image burning into his retina, but he refused to close his eyes. It was worth the risk of blindness. Where the lightning struck the water, flames erupted and danced across the pool's surface.

Fire from water!

He knew what he was witnessing.

The electrolysis of water into hydrogen gas and oxygen. The released gas then ignited, set to flame by the play of energies here.

Trapped by force, Gray watched the fire above and below. He could barely comprehend the power being unleashed here.

He had read theoretical studies on how a superconductor could store energy, even light, within its matrix for an infinite span of time. And in a perfect perfect superconductor even the quant.i.ty of energy or light could be infinite. superconductor even the quant.i.ty of energy or light could be infinite.

Was that what he was witnessing?

Before he could grasp it fully, the energies suddenly died away, a lightning storm in a bottle, brilliant but brief.

The world swung back upright as the Meissner field expired and his body was released. Gray stumbled a step forward. He caught himself from falling into the pool. Fires died back into the water. Whatever energy had been trapped inside the pyramid had been expended.

No one spoke.

They silently gathered together, needing the company of others, the physicality of one another.

Vigor was the first to make coherent motion. He pointed to the ceiling. "Look."

Gray craned. The black paint and stars persisted, but now strange letters glowed in a fiery script across the dome of the roof.

"It's the clue," Rachel said.

As they stared, the letters faded rapidly. Like the fiery pyre atop the black hemat.i.te slab at St. Peter's, the revelation only lasted a brief time.

Gray hurried to free his underwater camera. They needed a record.

Vigor stayed his hand. "I know what it says. It's Greek."

"You can translate?"

The monsignor nodded. "It's not difficult. It's a phrase attributed to Plato, describing how the stars affect us and are in fact a reflection of us. It became the foundation for astrology and the cornerstone for Gnostic belief."

"What's the phrase?" Gray asked.

"'As it is above, so it is below.'"

Gray stared at the starry ceiling and at the reflection in the water. Above and below. Here was the same sentiment expressed visually. "But what does it mean?"

Rachel had wandered from the group. She slowly made a complete circuit of the room. She called from the far side of the pyramid. "Over here!"

Gray heard a splash.

They hurried over to her. Rachel waded toward the pyramid.

"Careful," Gray warned.

"Look," she said, and pointed.

Gray made it around the edge of the pyramid and saw what had excited her. A tiny section of the pyramid, six inches square, had vanished midway up one face, dissolved away, consumed during the firestorm. Resting inside the hollow lay one of Alexander the Great's outstretched hands, closed in a fist.

Rachel reached for it, but Gray motioned her away.

"Let me," he said.

He reached to touch the hand, glad he was still wearing his diving gloves. The brittle flesh felt like stone. Between the clenched fingers, a bit of gold glinted.