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."
There was no difficulty in conversation. With the plate glass window in front of the pilot's seat and the hatch to the motor-room closed, the compartment was practically cut off, both from external and internal noises. Except for the muffled pulsations of the motors and the subdued roar from the propellers, there was little to indicate that the flying-boat was cutting through the air at eighty-five miles an hour.
"It's a jolly lucky thing we didn't carry on in the motor-boat," remarked Peter. "Look down there."