Ted looked in that direction and nodded assent. Far ahead, and to one side, lay a circle of yellow vapor; it seemed to hug the earth in a solid ring, while columns and whisps rose into the sky to a great height. That could mean but one thing. It was the impenetrable barrier of poisonous gases arising from the chain of volcanoes surrounding the Hidden Valley. A quarter of an hour later they had crossed the margin of the ring. There it was, directly beneath them--the long valley with its winding river, Uti with the dismal lagoon glistening in the sunlight, and the great wall that separated the two places showing like a narrow gray ribbon. To the left was another valley with high, steep walls of rock hemming it in on all sides, but there was no vapor clinging to the rim of that enclosure. Stanley shut down the power and they began a rapid and almost noiseless descent in a series of graceful spirals. When down to five hundred feet above the ground, he again opened the throttle and circled a few times, while both craned their heads over the sides of the cockpits, looking for a suitable place to land. In a moment they recognized the level strip of beach on the border of the lake, the very spot, in fact, where their canoe had been stranded several years before; another spiral, then a long glide, and they had landed on the hard sand. At last they were in the region of gold-filled caves, a mere stone’s throw from the place where the vast treasure of the Incas had lain untouched for so many centuries. The two scrambled out of their cramped quarters and jumped to the ground. Then, dashing their helmets and goggles aside, they started in a wild rush toward the cave. CHAPTER VI THE CROWNING MISFORTUNE Upon reaching the entrance to the underground chamber they stopped. The vision of Timichi, the demented, self-styled king they had encountered on their previous visit, loomed up before them. What if he were still alive and had observed their approach? It was not probable, for even years ago he had been very old and in ill health; but it was just barely possible that he still lived. In that event he would be awaiting them in the darkened passageway with some heavy weapon with which to attack them. He had every advantage, and that he would submit to the seizure of the treasure without putting up a fight was out of the question. “Let’s call to him,” Ted suggested. “Perhaps he will recognize our voices or his name and come out--if he is in there.” They called “Timichi,” then “Loco,” which latter was the name he had liked and which applied to him so well. But there was no response. Then they advanced slowly, but no sinister figure dashed out of the blackness to dispute their way.