"Yes; but it was for economical reasons," continued his uncle. "Apparently the Rioguayan authorities never contemplated an attempt to cut it. We'll do our utmost to prove the fallacy of their belief in its immunity." By the aid of binoculars, the track of the huge oil-pipe was located. So far so good; but there still remained the task of finding a suitable landing-ground. The flying-boat, although provided with means for alighting both on the water and on land, could not reasonably be expected to come to rest on tree-tops without the almost certain risk of being completely destroyed. At two hundred metres the aircraft followed the line--until Peter discovered a possible landing in a clearing about fifty yards from the Englishman's objective. Here, for the first time since leaving the island, they saw signs of human habitation--small _adobe_ huts. "All right, I suppose?" asked Peter. "Yes, they're Indians in the pay of the Rioguayan Government," replied Uncle Brian. "They are paid, I understand, not for the work they do, but for the damage they don't do--sort of retaining fee, providing they are good and don't start carving pieces out of the iron pipe." "I see," remarked Peter. "Then, as far as we are concerned, they need not be taken into account. S'pose they won't carve up our engineer bird when we set him ashore?" "They will more likely take him down to El Toro and get paid for the job," said Uncle Brian. His nephew nodded. He was now engaged upon the task of bringing the flying-boat to earth, no easy task in a strange 'bus and on a landing-ground of doubtful quality and very limited extent. With a succession of slight jolts, the flying-boat was brought to rest with her nose within ten feet of one of the huts. No Indians came out to gaze curiously at the wonderful sight, or to beg tobacco from the crew. They had promptly taken to the bush at the first distant view of the strange, enormous mechanical bird. Bolting the hatch over the for'ard motor-room and at the same time telling the craven Rioguayan that there was nothing to be afraid of, provided he behaved himself, Peter and Brian Strong removed one of the fifty-pound bombs from the dropping gear and carried it ashore. Then, armed with rifles, they transported their bulky load to the enormous rust-red pipe-line that was raised eight feet above the ground, stretching miles in either direction, upon which depended the main kerosene supply to the Rioguayan arsenals and aerodromes. It was the work of a few minutes to place the bomb close to the pipe and "tamp" it with earth. In the absence of a time fuse, it was necessary to detonate the explosive by rifle-fire. At a safe distance, Peter put bullet after bullet at the target. The pipe was holed in several places, the oil gushing forth at high pressure, but it was not until the tenth shot that the desired result was attained.