And right in the middle of the circle was the airplane stolen from Bob and Frank. There could be no mistaking the all-metal body nor the peculiar wing spread, even at that distance of close to half a mile.
Several figures were moving about. As the boys looked on, these seized oil flares and started moving toward them.
"Here's where our turn comes at last," said Frank.
Jack laid a hand on his arm.
"Better than that, Frank," he said. "How many do you make out?"
"Three is my guess."
"The two men in the airplane and the man in charge of the cave," said Jack. "Dollars to doughnuts, the cave is undefended right this minute. What do you say to capturing it and laying for them there?"
All four were grouped together, and consequently all heard Jack's proposal. Bob and Tom Bodine agreed eagerly.
"Lead the way, then, Tom," said Jack, "because you know the route. And be quick."
Swiftly, yet withal cautiously, because the cave might be defended, they approached the big rock. As they sidled around it, a gleam of light from the mouth of the cave at the rear of the rock fell athwart their path. Involuntarily they drew back.