At Brian Strong's orders, backed up by an indisputable argument in the shape of a pistol, the man was marched along the alley-way to the gangway and told to go ashore and bring back the grapnel and mooring rope. This he did. "Now," continued Brian sternly, "you can go and stand over there," indicating a spot close to the mangled remains of the "orange-box". "If you shift from there while you are within range of a rifle, you won't stir more than half a dozen steps. I'm a crack shot.... All right, Peter. Away as soon as you like." The remaining mechanic was ordered for'ard to start the motors. For the present the flying-boat was to be actuated only by the bow propellers, those aft being required only when proceeding at top speed. Then Peter, having lowered the body of his victim to the water, took his place in the "office". By this time the flying-boat, no longer tethered by the rope and grapnel, had drifted from the island before the light offshore wind. The motors were throbbing tunefully. A forward thrust of one lever was sufficient to bring both propellers in gear. Like a gigantic water-fowl, the aerial craft leapt forward, leaving a feathery wake on the surface of the lake. When the speed gauge indicated thirty-eight kilometres, Peter manipulated another lever, and, obedient to the alteration of trim of her short, cambered planes, the flying-boat soared into her proper element. "A 'bus for an orange-box," soliloquized the light-hearted pilot. "Not a bad exchange, eh what?" CHAPTER XV Over the Sierras Presently Uncle Brian rejoined his nephew. The flying-boat was now at an altitude of 4000 metres and following the course of the Rio del Morte. From the island from which they had made their escape rifle bullets were singing harmlessly, for the searchers, upon hearing the hum of the flying-boat's engines, had jumped to the conclusion--a correct one in this case--that the "English dogs" had scored rather heavily. "She's well stocked in the food department," reported Uncle Brian, "and there's plenty of fuel in the tanks. With reasonable luck we'll cross the Sierras before sunset." "And then----?" "Make for Trinidad or Barbadoes," replied Peter's uncle, as he carefully stowed the haversack containing the secret-rays parts into a locker. "She'll do that easily. But I've a notion that I'd like to stop and have a look at the pipe-line between El Toro and Tajeco. We might be able to cut off the fuel supply to the Rioguayan Air Fleet." "Right-o," agreed Peter. "And what about Antonio?" "Who?" asked his uncle. "Antonio, our mechanic," explained Peter, indicating the closed hatchway, underneath which the Rioguayan engineer was quaking and trembling. "He'll be a bit of a nuisance on board, although he hasn't the pluck of a mouse. Can't we land him somewhere? Between us we can manage quite all right."