Stung with rage, the enemy disregard the terms of the contest and attack with their whole army. They are, however, defeated, and the conquered Jarmuthians sullenly turn over Alden and the captive maidens; though Altara still remains in their possession. After making much of the Americans, Altorius reluctantly allows his preservers to depart for their plane--unconscious that the priestly party is planning rebellion against his authority because he did not insist on Altara's return. CHAPTER VII "That's one of the fixed retortiis I was speaking about," remarked Victor Nelson as he paused to point out a tapering brass tube which was mounted on a platform above the long staircase up which he and Alden were toiling. "It's a big brute: see how small the gunners look beside it? These steam guns are wonderful things." The younger aviator sighed. "I've had enough of miracles," he said wiping his flushed features and hitching a small pack higher on his leather-clad shoulders. "All I want to do is to lay my weary eyes on the plane again. What with these ghastly allosauri, diplodocuses and other monsters, I'm damn well fed up with this place." Nelson settled his Winchester rifle more comfortably into the hollow of his arm. "Correct. So am I. But we can't say Altorius didn't do right by our Nell. Good Lord, what a triumph he gave us!" The dark pilot's smile flashed from beneath his neat, close-clipped black mustache. "Wait till Cartier gets a peep at those diamonds he gave us." Panting, the two halted by mutual consent. "Ever see so many stairs?" grunted Nelson. "Three more flights and we'll be into the tunnel; ah, there's the opening. I only hope these blighters haven't hurt the plane." Before resuming the climb Nelson shifted his rifle, idly regarding the armored gunners just above; then suddenly he stiffened his wiry body with a sharp cry. "Look out, Dick! What the devil? Those damn fools ahead are swinging the retortii across our--" * * * * * The dark haired aviator's words were drowned out in a deafening, hissing roar that burst from the great retortii's throat, and his heart gave a great convulsive leap at the sight. Was this an accident--or treachery? An accident of course. Somehow he could not bring himself to think that Altorius would break his pledged word. Projected in a shimmering white arm the scalding death vapor shot across the staircase, its hot breath licking the faces of the startled and angry Americans, and quickly forcing them to turn and run downwards to avoid being scalded. "What the devil are these idiots trying to do?" gasped Nelson, anxiously eyeing the red-crested warriors who, peering down through the blue lenses of their helmets, watched the khaki-clad aviators but made no effort to realign their retortii. "Hero Giles'll skin those fools alive if he hears of this. Guess we'd better wait a minute: they'll soon shut off the steam."