"What do you mean, Koku?" asked Tom. "Is that why you fought him? Did he try to wreck the tunnel?"

"So him done, Master. But Koku see--Koku stop. Then um fight."

"Be jabbers an' I wouldn't wonder but what he was right!" cried Tim Sullivan, excitedly. "I did see that beggar." and he pointed to Lamos, who was slowly crawling away, "at the chist where I kape th' powder, but I thought nothin' of it at th' time. What did he try t' do, Koku?"

Then the giant explained in his own language, Tom Swift translating, for Koku spoke English but indifferently well.

"Koku says," rendered Torn, "that he saw Lamos trying to put a big charge of powder up in the place where the balanced rock fits in the secret opening of the tunnel roof. The charge was all ready to fire, and if the giant had set it off he might have brought down the roof of the tunnel and so choked it up that we'd have been months cleaning it out. Koku saw him and stopped him, and then the fight began. We only saw the end."

"Bless my shoe string!" gasped Mr. Damon. "And a terrible end it was.

Will Lamos die?"

"I don't think so," answered Job t.i.tus. "But he will be a cripple for life. Not only would he have wrecked the tunnel, but he would have killed many of our men had he set off that blast. Koku saved them, though it seems too bad he had to fight to do it."

An investigation showed that Koku spoke truly. The charge, all ready to set off, was found where he had knocked it from the hand of Lamos. And so Tom's giant saved the day. Lamos was sent back to his own village, a broken and humbled giant. And to this day, in that part of Peru, the great struggle between Koku and Lamos is spoken of with awe where Indians gather about their council fires, and they tell their children of the t.i.tanic fight.

"It was part of the plot," said Job t.i.tus when the usual blast had been set off that day, with not very good results. "This giant was sent to us by our rivals. They wanted him to hamper our work, for they see we have a chance to finish on time. I think that foreman, Serato, is in the plot. He brought Lamos here. We'll fire him!"

This was done, though the Indian protested his innocence. But he could not be trusted.

"We can't take any chances," said Job t.i.tus. "Our time is too nearly up. In fact I'm afraid we won't finish on time as it is. There is too much of that hard rock to cut through."

"There's only one thing to do," said Tom, after an investigation. "As you say, there is more of that hard rock than we calculated on. To try to blast and take it out in the ordinary way will be useless. We must try desperate means."

"What is that?" asked Walter t.i.tus.

"We must set off the biggest blast we can with safety. We'll bore a lot of extra holes, and put in double charges of the explosive. I'll add some ingredients to it that will make it stronger. It's our last chance. Either we'll blow the tunnel all to pieces, or we'll loosen enough rock to make sufficient progress so we can finish on time. What do you say? Shall we take the chance?"

The t.i.tus brothers looked at one another. Failure stared them in the face. Unless they completed the tunnel very soon they would lose all the money they had sunk in it.

"Take the chance!" exclaimed Job. "It's sink or swim anyhow. Set off the big blast, Tom."

"All right. We'll get ready for it as soon as we can."

That day preparations were made for setting off a great charge of the powerful explosive. The work was hurried as fast as was consistent with safety, but even then progress was rather slow. Precautions had to be taken, and the guards about the tunnel were doubled. For it was feared that some word of what was about to be done would reach the rival firm, who might try desperate means to prevent the completion of the work.

There was plenty of the explosive on hand, for Mr. Swift had sent Tom a large shipment. All this while no word had come from Mr. Nestor, and Tom was beginning to think that his prospective father-in-law was very angry with him. Nor had Mary written.

Professor b.u.mper came and went as he pleased, but his quest was regarded as hopeless now. Tom and his friends had little time for the bald-headed scientist, for they were too much interested in the success of the big blast.

"Well, we'll set her off to-morrow," Tom said one night, after a hard day's work. "The rocky wall is honeycombed with explosive. If all goes well we ought to bring down enough rock to keep the gangs busy night and day."

Everything was in readiness. What would the morrow bring--success or failure?

Chapter XXIV

The Hidden City

Gathered beyond the mouth of the tunnel, far enough away so that the wind of the great blast would not bowl them over like ten pins, stood Tom Swift and his friends. In his hand Tom held the battery box, the setting of the switch in which would complete the electrical circuit and set off the hundreds of pounds of explosive buried deep in the hard rock.

"Are all the men out?" asked the young inventor of Tim Sullivan, who had charge of this important matter. Tim was in sole charge as foreman now, having picked up enough of the Indian language to get along without an interpreter.

"All out, sor," Tim responded. "Yez kin fire whin ready, Mr. Swift."

It was a portentous moment. No wonder Tom Swift hesitated. In a sense he and his friends, the contractors, had staked their all on a single throw. If this blast failed it was not likely that another would succeed, even if there should be time to prepare one.

The time limit had almost expired, and there was still a half mile of hard rock between the last heading and the farther end of the big tunnel. If the blast succeeded enough rock might be brought down to enable the work to go on, by using a night and day shift of men. Then, too, there was the chance that the hard strata of rock would come to an end and softer stone, or easily-dug dirt, be encountered.

"Well, we may as well have it over with," said Tom in a low voice.

Every one was very quiet--tensely quiet.

The young inventor looked up to see Professor b.u.mper observing him.

"Why, Professor!" Tom exclaimed, "I thought you had gone off to the mountains again, looking for the lost city."

"I am going, Tom, very soon. I thought I would stop and see the effect of your big blast. This is my last trip. If I do not find the hidden city of Pelone this time, I am going to give up."

"Give up!" cried Mr. Damon. "Bless my fountain pen!"

"Oh, not altogether," went on the bald-headed scientist. "I mean I will give up searching in this part of Peru, and go elsewhere. But I will never completely give up the search, for I am sure the hidden city exists somewhere under these mountains," and he looked off toward the snow-covered peaks of the Andes.

Tom looked at the battery box. He drew a long breath, and said:

"Here she goes!"

There was a contraction of his hand as he pressed the switch over, and then, for perhaps a half second, nothing happened. Just for an instant Tom feared something had gone wrong that the electric current had failed, or that the wires had become disconnected--perhaps through some action of the plotting rivals.

And then, gently at first, but with increasing intensity, the solid ground on which they were all standing seemed to rock and sway, to heave itself up, and then sink down.

"Bless my--" began Mr. Damon, but he got no further, for a mighty gust of wind swept out of the tunnel, and blew off his hat. That gust was but a gentle breeze, though, compared to what followed. For there came such a rush of air that it almost blew over those standing near the opening of the great shaft driven under the mountain. There was a roar as of Niagara, a howling as in the Cave of the Winds, and they all bent to the blast.

Then followed a dull, rumbling roar, not as loud as might have been expected, but awful in its intensity. Deep down under the very foundations of the earth it seemed to rumble.

"Run! Run back!" cried Tom Swift. "There's a back-draft and the powder gas is poisonous. Stoop down and run back!"

They understood what he meant. The vapor from the powder was deadly if breathed in a confined s.p.a.ce. Even in the open it gave one a terrible headache. And Tom could see floating out of the tunnel the first wisps of smoke from the fired explosive. It was lighter than air, and would rise. Hence the necessity, as in a smoke-filled room, of keeping low down where the air is purer.

They all rushed back, stooping low. Mr. Damon stumbled and fell, but Koku picked him up and, tucking him under one arm, as he might have done a child, the giant followed Tom to a place of safety.

"Well, Tom, it went off all right," said Mr. Job t.i.tus, as they stood among the shacks of the workmen and watched the smoke pouring out of the tunnel mouth.

"Yes, it went off. But did it do the work? That's what we've got to find out."

They waited impatiently for the deadly vapor to clear out of the tunnel. It was more than an hour before they dared venture in, and then it was with smarting eyes and puckered throats. But the atmosphere was quickly clearing.