Presently they, too, passed out of the Englishmen's arc of vision; but from auricular evidence, it was plain that they were experiencing considerable difficulty in persuading the animal to scale the cliff. But one point was distressingly in evidence; the hound was already on the trail, since he had indicated the way by which Uncle Brian and Peter had gained the summit.
It seemed quite a long interval before the baying of the hound announced that the feat of the ascent was accomplished. Momentarily the two fugitives expected to hear their pursuers descending the narrow gorge in which they were concealed, but minutes passed without their unpleasant expectation being realized.
Gradually the deep notes of the dog, accompanied by the encouraging shouts of the searchers and the occasional report of firearms, died away.
"Good business," whispered Peter. "The brute's picked up the wrong scent. He's following my track where I went this morning."
Which was exactly what the hound was doing, accompanied by the airmen who were firing at haphazard into every bush they passed, on the chance of compelling their quarry to abandon a possible place of concealment.
Peter took another look at the flying-boat. He could see the officer in charge sitting up in the for'ard cockpit with a rifle laid upon the decking by his side. There was no one else visible, but in front of the Rioguayan was an automatic gun somewhat resembling a Colt, with its muzzle pointing ominously in the direction of the way down the cliff.
"We'll have to rush the 'bus, Uncle," said Peter in a low voice. "It's our only chance."
Uncle Brian nodded, and raising the haversack from the ground, slung it over his shoulder.
"Right," he whispered. "Lead on, but keep a sharp look-out in case there's a man on guard on the cliff. If there is, no firing if it can be avoided, mind."
His nephew gave a sign of assent and replaced his automatic, taking the precaution of leaving the flap of the holster unfastened. Then, with his uncle close at his heels, he crept cautiously along the gully, till he arrived at the slightly rugged ground adjoining the brink of the cliff.