The plane was obviously nearing its eyrie—dropping lower and lower, losing speed and altitude; and also threatening each moment to tumble down out of control into the smothering welter of olive-green below, with a dead, unseen body in its cockpit.
But where was the landing field? They were now over the very heart of the Peninsula, and still Chris, searching through his telescopic sight, could see nothing but the monotonous roll of jungle. They must come to it soon, or be over to the Caribbean Sea and the Mosquito Gulf.
Then suddenly he started forward, staring. Of course there was no landing field in sight. The mystery plane needed none. It possessed the power of the helicopter: it could rise straight up or sink straight down.
From each one of the two knob-like projections on its upper wing that had puzzled him previously, a propeller had risen and unfolded into long, flat blades. They whirled in circles of light in the sun; and the airplane beneath them poised, all but motionless, its main propeller swinging idly, and then began slowly to drop downwards.
But Chris, swooping nearby, was still perplexed. Dropping down to what? There was only the dense tropical growth beneath. He could see no trace of men, no clearing, however small, no base—nothing but the jungle.
"How in the dickens—" he began; and then stopped. At that moment the jungle's secret was revealed.
As the helicopter-plane dropped to within a few hundred feet of it, a strip of the sea verdure split in two and reared up. It looked, at first, like magic. But from aloft Chris saw the trick and how the camouflage was worked. What appeared to be a slice of the jungle roof was, in reality, a metal framework cunningly plastered with layers of green growth. An oblong, some fifty by a hundred feet, it parted in the middle like a bridge that opens to let a steamer through, revealing the lair of the plane.
Soon more was revealed. Two tiny, green-painted huts stood in the minute clearing, and a few white-clad figures were by them, staring up at the plane sinking down and at the other plane which soared above like a buzzing mosquito.
One of the dwarfed figures in white waved an arm. The others around him darted into the left-side hut. Then the helicopter-plane's wheels touched the small space allotted for it in the clearing, and the whirling propellers halted.