Chapter XX. The City of Gold
 

"Well, I guess this is the end of it," remarked Ned ruefully, as they stood contemplating the roaring stream by the gleam of their electric flash lamps. "We can't go on to the city of gold unless we swim that river, and--"

"And none of us is going to try that!" interrupted Tom sharply. "The strongest swimmer in the world couldn't make a yard against that current. He'd be carried down, no one knows where."

"Bless my bathing suit, yes!" exclaimed Mr. Damon. "But what are we to do? Can't we make a raft, or get a boat, or something like that?"

"Hab t' be a mighty pow'ful boat t' git across dat ribber ob Jordan," spoke Eradicate solemnly.

"That's right," agreed Ned. "But say, Tom, don't you think we could go back, get a lot of trees, wood and stuff and make some sort of a bridge? It isn't so very wide--not more than thirty or forty feet. We ought to be able to bridge it."

"I'm afraid not," and Tom shook his head. "In the first place any trees that would be long enough are away at the far edge of the big plain, and we'd have a hard job getting them to the temple, to say nothing of lugging them down the tunnel. Then, too, we don't know much about building a bridge, and with no one on the other side to help us, we'd have our hands full. One slip and we might be all drowned. No, I guess we've got to go back," and Tom spoke regretfully. "It's hard luck, but we've got to give up and go back."

"Den I's pow'ful glad I got ma golden image when I did, dat's suah!" exclaimed Eradicate. "Ef we doan't git no mo' I'll hab one. But I'll sell it and whack up wid yo' all, Massa Tom."

"You'll do nothing of the sort, Rad!" exclaimed the young inventor. "That image is yours, and I'm sorry we can't get more of them."

He turned aside, and after another glance at the black underground river which flowed along so relentlessly he prepared to retrace his steps along the tunnel.

"Say, look here!" suddenly exclaimed Ned. "I'm not so sure, after all that we've got to turn back. I think we can go on to the city of gold, after all."

"How do you mean?" asked Tom quickly. "Do you think we can bring the balloon down here and float across?"

"Bless my watch chain!" exclaimed Mr. Damon, "but that would be a way. I wonder--"

"No, I don't mean that way at all," went on Ned. "But it seems to me as if this river isn't a natural one--I mean that it flows along banks of smooth stone, just as if they were cut for it, a canal you know."

"That's right," said Tom, as he looked at the edge of the channel of the underground stream. "These stones are cut as cleanly as the rest of the tunnel. Whoever built that must have made a regular channel for this river to flow in. And it's square on the other side, too," he added, flashing his lamp across.

"Then don't you see," continued Ned, "that this river hasn't always been here."

"Bless my gaiters!" gasped Mr. Damon, "what does he mean? The river not always been here?"

"No," proceeded Tom's chum. "For the ancients couldn't have cut the channel out of stone, or made it by cementing separate stones together while the water was here. The channel must have been dry at one time, and when it was finished they turned the water in it."

"But how is that going to help us?" asked Tom. "I grant you that the river may not have been here at one time, but it's here now, which makes it all the worse for us."

"But, Tom!" cried his chum, "if the river was turned aside from this channel once it can be done again. My notion is that the ancients could make the river flow here or not, just as they choose. Probably they turned it into this channel to keep their enemies from crossing to the city of gold, like the ancient moats. Now if we could only find--"

"I see! I see!" cried Tom enthusiastically. "You mean there must be some way of shutting off the water."

"Exactly," replied his chum. "We've got to shut that stream of water off, or turn it into some other channel, then we can cross, and keep on to the city of gold. And I think there must be some valve--some lever, or handle or something similar to the one that moved the altar-near here that does the trick. Let's all look for it."

"Bless my chopping block!" cried Mr. Damon. "That's the strangest thing I ever heard of! But I believe you're right, Ned. We'll look for the handle to the river," and he laughed gaily.

Every one was in better spirits, now that there seemed a way out of the difficulty, and a moment later they were eagerly flashing their lamps on the sides, floor and ceiling of the tunnel, to discover the means of shutting off the water. At first they feared that, after all, Ned's ingenious theory was not to be confirmed. The walls, ceiling and floor were as smooth near the edge of the river as elsewhere.

But Eradicate, who was searching as eagerly as the others, went back a little, flashing his lamp on every square of stone. Suddenly he uttered a cry.

"Look yeah, Massa Tom! Heah's suffin' dat looks laik a big door knob. Maybe yo' kin push it or pull it."

They rushed to where he was standing in front of a niche similar to the one where he had found the golden image. Sunken in the wall was a round black stone. For a moment Tom looked at it, and then he said solemnly:

"Well, here goes. It may shut off the water, or it may make it rise higher and drown us all, or the whole tunnel may cave in, but I'm going to risk it. Hold hard, everybody!"

Slowly Tom put forth his hand and pushed the knob of stone. It did not move. Then he pulled it. The result was the same--nothing.

"Guess it doesn't work any more," he said in a low tone.

"Twist it!" cried Ned. "Twist it like a door knob."

In a flash Tom did so. For a moment no result was apparent, then, from somewhere far off, there sounded a low rumble, above the roar of the black stream.

"Something happened!" cried Mr. Damon.

"Back to the river!" shouted Tom, for they were some distance away from it now. "If it's rising we may have a chance to escape."

They hurried to the edge of the stone channel, and Ned uttered a cry of delight.

"It's going down!" he yelled, capering about. "Now we can go on!"

And, surely enough, the river was falling rapidly. It no longer roared, and it was flowing more slowly.

"The water is shut off," remarked Tom.

"Yes, and see, there are steps which lead across the channel," spoke Ned, pointing to them as the receding water revealed them. "Everything is coming our way now."

In a short time the water was all out of the channel, and they could see that it was about twenty feet deep. Truly it would have been a formidable stream to attempt to swim over, but now it had completely vanished, merely a few little pools of water remaining in depressions on the bottom of the channel. There were steps leading down to the bottom, and other steps ascending on the other side, showing that the river was used as a barrier to further progress along the tunnel.

"Forward!" cried Tom gaily, and they went on.

They went down into the river channel, taking care not to slip on the wet steps, and a few seconds later they had again ascended to the tunnel, pressing eagerly on.

Straight and true the tunnel ran through the darkness, the only illumination being their electric flash lamps. On and on they went, hoping every minute to reach their goal.

"Dish suah am a mighty long tunnel," remarked Eradicate. "Dey ought t' hab a trolley line in yeah."

"Bless my punching bag!" cried Mr. Damon, "so they had! Now if those ancients were building to-day--"

He stopped suddenly, for Tom, who was in the lead, had uttered a cry. It was a cry of joy, there was no mistaking that, and instinctively they all knew that he had found what he had sought.

All confirmed it a moment later, for, as they rushed forward, they discovered Tom standing at the place where the tunnel broadened out- -broadened out into a great cave, a cave miles in extent, for all they could tell, as their lamps, powerful as they were, only illuminated for a comparatively short distance.

"We're here!" cried Tom. "In the city of gold at last!"

"The city of gold!" added Ned. "The underground city of gold!"

"And gold there is!" fairly shouted Mr. Damon. "See it's all over! Look at the golden streets--even the sides of the buildings are plated with it--and see, in that house there are even gold chairs! Boys, there is untold wealth here!"

"An' would yo' all look at dem golden statues!" cried Eradicate, "dey mus' be millions ob 'em! Oh, golly! Ain't I glad I comed along!" and he rushed into one of the many houses extending along the street of the golden city where they stood, and gatheredup a fairly large statue of gold--an image exactly similar to the one he already had, except as to size.

"I never would have believed it possible!" gasped Tom. "It's a city of almost solid gold. We'll be millionaires a million times over!"