Inca Gold (Dirk Pitt 12)

"Maybe I can do my bit for the cause," said Pitt, holding up a small waterproof computer before strapping it to his forearm. "I'll try to program a survey, and plot data on the river's course as we go."

"I'll be grateful for all the scientific data you can bring back," acknowledged Duncan. "Finding a golden treasure under Cerro el Capirote may fire the imagination, but in reality it's incidental to the discovery of a water source that can turn millions of acres of desert into productive farm and ranch land."

"Perhaps the gold can fund the pumping systems and pipelines for such a project," said Pitt.

"Certainly a dream to consider," added Sandecker.

Giordino held up an underwater camera. "I'll bring back some pictures for you."

"Thank you," said Duncan gratefully. "I'd also appreciate another favor."

Pitt smiled. "Name it."

He handed Pitt a plastic packet in the shape of a basketball but half the size. "A dye tracer called Fluorescein Yellow with Optical Brightener. I'll buy you the best Mexican dinner in the Southwest if you'll throw it into the river when you reach the treasure chamber. That's all. As it floats along the river the container will automatically release the dye over regular intervals."

"You want to record where the river outlet emerges into the Gulf."

Duncan nodded. "That will give us an important hydrologic link."

He was also going to ask if Pitt and Giordino might take water samples, but thought better of it. He had already pushed them as far as he dared. If they were successful in navigating the river as far as the hollow interior of Cerro el Capirote, then he and his fellow scientists could mount subsequent scientific expeditions based on the data acquired by Pitt and Giordino.

Over the next ten minutes, Pitt and Giordino geared up and went over the plans for their journey. They had made countless dives together under a hundred different water and weather conditions, but none of this distance through the depths of the earth. Like doctors discussing a delicate brain operation, no detail was left to chance. Their survival depended on it.

Communication signals were agreed upon, buddy breathing strategies in case of air loss, the drill for inflating and deflating the Wallowing Windbag, who was in control of what equipment-- all procedures were deliberated and jointly approved.

"I see you're not wearing a pressurized dry suit," observed Sandecker as Pitt pulled on his wet suit.

"The water temperature is a few degrees on the cool side, but warm enough so we don't have to worry about hypothermia. A wet suit gives us more freedom of movement than a dry suit that is pressurized by air tanks. This will prove a dire necessity if we find ourselves struggling in the water to right the Wallowing Windbag after it is flipped over by raging rapids."

Instead of the standard backpack, Pitt attached his air tanks to a harness around his hips for easier access through narrow passages. He was also festooned with breathing regulators, air lines leading to dual valve manifolds, pressure gauges, and a small backup bottle filled with pure oxygen for decompression. Then came weight belts and buoyancy compensators.

"No mixed gas?" queried Sandecker.

"We'll breathe air," Pitt replied as he checked his regulators.

"What about the danger of nitrogen narcosis?"

"Once we're clear of the bottom of the sinkhole and the lower part of the feeder stream before it upslopes to the river, we'll avoid any further deep diving like the plague."

"Just see that you stay well above the threshold," Sandecker warned him, "and don't go below thirty meters. And once you're afloat keep a sharp eye for submerged boulders."

Those were the words the admiral spoke. What he didn't say was, "If something goes wrong and you need immediate help, you might as well be on the third ring of Saturn." In other words, there could be no rescue or evacuation.

Pitt and Giordino made a final predive check of each other's equipment by the side of the pool and tested their ` quick-release buckles and snaps to ensure their smooth removal in an emergency. Instead of divers' hoods, they strapped construction workers' hardhats to their heads with dual-sealed miners'

lamps on the front. Then they poised on the edge of the sinkhole and slipped into the water.

Sandecker and Duncan hoisted a long, pressure-sealed aluminum canister and struggled to lower one end into the sinkhole. The canister, measuring one meter in width by four in length, was articulated in the middle for easier maneuvering through tight spaces. Heavy and cumbersome on land from the lead ballast required to give it neutral buoyancy, it was easily moved by a diver underwater.

Giordino bit on his mouthpiece, adjusted his mask, and took hold of a handgrip on the forward end of the canister. He threw a final wave as he and the canister slowly sank together below the water surface.

Pitt looked up from the water and shook hands with Duncan.

"Whatever you do," Duncan warned him, "mind you don't let the current sweep you past the treasure chamber. From that position to where the river emerges into the Gulf has to be over a hundred kilometers."

"Don't worry, we won't spend any more time down there than we have to."

"May God dive with you," said Duncan.