With his altimeter registering five thousand feet, Biggles looked a trifle apprehensively over the side of his cockpit at the unusual scene below as he headed westwards in the amphibian he had purchased. Immediately below, a broad, winding silver ribbon marked the course of the mighty sss, the largest river in the world. On both sides lay the forest, dark and unfathomable, like a great sombre pall over the face of the earth, merging into vague purple and blue shadows at the remote horizon. There was nothing else; not a road, a field, or an isolated tree that might be taken for a landmark. The utter sameness of it all had appalled him at first, but now he was growing accustomed to it, for they were far up the river, approaching Manaos, the strange city founded by gold-hunters hundreds of ye
