"Hop in!" cried Tom. "She'll go up I guess."
"There they come!" shouted Ned, as he spoke the foremost of the head-hunters emerged from the hole beneath the stone altar. He was followed by Delazes.
"Stop them! Get them! Spear them!" cried the contractor. They evidently thought our friends had all the gold from the underground city.
Fortunately the temple was so large that the balloon was a good distance from the hole leading to the tunnel, and before the foremost of the head-hunters could reach it the dirigible began to rise.
"If they throw their spears, and puncture the bag in many places we're done for," murmured Tom. But evidently the savages did not think of this, though Delazes screamed it at them.
Up went the balloon, and not a moment too soon, for one of the head-hunters actually grabbed the edge of the car, and only let go when he found himself being lifted off the temple floor.
Up and up it went and, as it was about to emerge from the broken dome, Tom looked down and saw a curious sight.
Mr. Foger and Andy, who brought up in the rear of the pursuing and attacking party, had just emerged from the hole by the great stone altar when there suddenly spouted from the same opening a solid column of water. A cry of wonder came from all as they saw the strange sight. A veritable geyser was now spurting in the very middle of the temple floor, and the head-hunters, the Mexicans and the Fogers ran screaming to get out of the way.
"Look!" cried Ned. "What happened?"
"The underground river must be running the wrong way!" answered Tom, as he prepared to set in motion the motor. "Either they accidentally turned some hidden lever, or when they raised the stone door they did it. The tunnel is flooded and--"