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 ther 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 Bumper 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.