He pointed to a cleft in the face of the cliff about twenty yards to the left of the spot where they had made the ascent. A closer acquaintance showed that the hollow was deep and narrow, descending steeply until it terminated in a natural breastwork about eight feet above the beach. Although open to the air, the enclosing walls of rock were sufficiently irregular to cut off direct observation; and as neither Peter nor his uncle had noticed the cleft from the beach, it being similar to a dozen others, they were fairly safe in assuming that they stood a chance of outwitting their pursuers. They could hear the drone of the motors, but were unable to see the inquisitive flying-boat. For some minutes the noise continued almost constant in volume, as if the machine were hovering in the vicinity. Then the sound grew louder and louder until it ceased abruptly. Peter knew what that meant. The Rioguayan airmen had discovered traces of the two Englishmen and were volplaning down to investigate. Suddenly the descending aircraft appeared within Peter's limited field of vision, since by cautiously peering over the breastwork he could command a view of the beach in the vicinity of the spot where the two Englishmen had landed. There was nothing to criticize adversely in the manner in which the flying-boat alighted on the surface. With hardly a splash the lightly-built hull took the water. A few revolutions of the for'ard pair of propellers and the flying-boat "taxied" until she touched the edge of the sandy beach. If there had been any doubts in the minds of Peter and his uncle as to the intentions of the Rioguayan airmen, there was now no uncertainty on that score. A couple of men jumped out and secured the gently swaying flying-boat by means of a grapnel and rope. Then several more leapt ashore, all fully armed with rifles, revolvers, and _machetes_. Almost their first act was to smash the little craft which the Englishmen had only just succeeded in repairing. The Rioguayans seemed to take a childish delight in their work of destruction, laughing, yelling, and gesticulating at the thought that they had run their quarry to its lair and had cut off the fugitives' means of escape. Not content with smashing the boat to firewood, they examined every article that was strewn on the beach, destroying some and passing the rest into the hull of the flying-boat. Peter glanced at his uncle and tapped his automatic significantly. At all events, he thought, since the Rioguayans had deprived them of a means to leave the barren island, there was no reason why the two Englishmen shouldn't open a destructive fire upon their now declared foes. At that short range there was a good chance of killing or wounding every man in the group on the beach. Uncle Brian shook his head. "Wait," he whispered. Peter felt positively mutinous. To remain inactive was to throw away their only chance of scoring heavily off their pursuers. "Why?" he demanded in a low voice.