"Look out! There's going to be trouble!" cried Tom.
"Well, we're ready for 'em!" answered Abe, grimly.
There was a moment of hesitation among the natives. Then they seemed to hold a consultation with the chief. It was over shortly. They broke into a run, and quickly advanced toward the cave. Tom and the others held their guns in readiness.
Suddenly the Indians halted. They gazed upward, and pointed to something in the air above their heads. They gave utterance to cries of fear.
"What is it; another storm coming?" asked Tom.
"Let's look," suggested Ned. He and Tom stepped to the mouth of the cave—they went outside. There was little danger from the natives now, as their attention was fixed on something else.
A moment later Tom and Ned saw what this was.
Floating in the air, almost over the cave, was a great airship—a large craft, nearly the size of the RED CLOUD. Hardly able to believe the evidence of their eyes, Tom and Ned watched it. Whence had it come? Whither was it going?
"It's a triplane!" murmured Ned.
"A triplane!" repeated Tom. "Yes—it is—and it's the airship of Andy Foger! Our rivals are on our track!"