The Master understood they were now coming to the bottom of part of the golden dyke. Undeviated by the hard rock, the tunnel continued to descend, with here and there a turn. Narrowly the Master scrutinized the floor, tapping it with the simitar as he crept onward, seeking indications of any possible trap that might hurl him into bottomless, black depths. Quite at once, a right-angled turning opened into a small chamber not above eight feet high by fifteen square. In this, silent, listening, the sweating fugitives gathered. The temperature was here oppressive, and the lamps burned blue with some kind of gas that stifled the lungs. Gas and smoke together, made breathing hard. A dull, roaring sound had begun to make itself vaguely audible, the past few minutes; and as the Legionaries stood listening, this was now rather plain to their ears. "This is a devil of a place for a multi-millionaire, I must say!" Bohannan exploded. Simonds laughed, with tense nerves. One or two others swore, bitterly cursing the men of El Barr. The Master, "Captain Alden," and Leclair, however, gave no heed. Already they were peering around, at the black walls where now only an occasional thread of gold was to be seen. Five openings led out of this singular chamber, all equally dark, narrow, formidable. "This seems to be a regular labyrinth, my Captain," said Leclair, in French. "Surely a trap of some kind. They are clever, these Arabs. They let the mouse run and hope, then--_voilà_--he is caught!" "It looks that way. But we're not caught yet. These infernal passageways are all alike, to me. We must choose one. Well--this is as good as any." He gestured toward an aperture at the left. "Men, follow me!" The passage they now entered was all of rock, with no traces whatever of gold. For a few hundred feet its course was horizontal; then it plunged downward like the first. And almost immediately the temperature began to mount, once more. "Faith, but I think we'd better be getting back!" exclaimed the major. "I don't care much for this heat, or that roaring noise that's getting louder all the time!" "You'll follow me, or I'll shoot you down!" the Master flung at him, crouching around. "I've had enough insubordination from _you_, sir! Not another word!" The stooping little procession of trapped Legionaries once more went onward, downward. The muffled roar, ahead of them, rose in volume as they made a final turning and came into a much more spacious vault where moisture goutted from the black walls. A thin, steamy vapor was rising from the floor, warm to the bare feet. A moment the Legionaries stood there, blinking in the vague lamplight, glad of the respite that permitted them to straighten up and ease cramped muscles. "No way out of _here_!" Bohannan grumbled. "Sure, we're at the end o' nowhere. Now if we'd only taken another passage--"