off. He thought he saw a movement among the ranks of the enemy, who had camped just beyond the gold hole.
"I guess they're coming!" cried the lad. "Get ready for them!"
The adventurers caught up their guns, and hurried to the entrance of the cave. Mr. Parker lingered behind, and was observed to be narrowly scanning the walls of the cavern.
"Come on, Parker, my dear man!" begged Mr. Damon. "We are in grave danger, and we need your help. Bless my life insurance policy but I never was in such a state as this."
"We may soon be in a worse one," was the answer of the gloomy scientist.
"What do you mean?" asked Mr. Damon, but he hurried on without waiting for a reply.
Suddenly, from without the cave came a series of fierce yells. It was the battle-cry of the Indians. At the same moment there sounded a fusillade of guns.
"The battle is beginning!" cried Tom Swift, grimly. He held his electric gun, though he had not used it very much in the previous attack, preferring to save it for a time of more need.
As the defenders of the cave reached the entrance they saw the body of natives rushing forward. They were almost at the gold hole, with
