At a second command from the girl the men filed down to the water’s edge, where a long, low craft constructed of white metal, was moored. It was fashioned in the shape of a flying dragon like the one he had seen the girl riding some time before, the metallic wings held upward with edges closing at the top to make a fantastic roof for the cabin. As it was without rudder, oars or paddles, Ted was puzzled as to its means of locomotion. Beckoning him to follow, the girl leaped lightly aboard. As the earth man stepped in after her, one of the warriors pushed off and another, seated in the prow before a small keyboard, pressed several buttons with his fingers. There was a roar from the rear of the craft and it shot backward into midstream. The helmsman pressed another row of buttons and the boat started down stream with a louder roar and a terrific burst of speed. Making his way astern, Ted saw that the boat was both propelled and steered by two sets of three jointed pipes each, which extended from the back of the boat under water. Something, either highly compressed air or some other gas, rushed out of each pipe as the correct button was touched by the operator, and the wake, as a result, was a mass of seething bubbles. To turn right or left the helmsman had only to shut off the set of pipes on the side toward which he wished to go. To reverse the boat, he but needed to press buttons which bent the flexible jointed ends of the pipes downward and toward the front, thus reversing the direction of the pressure. Going forward once more, Ted crouched by the side of the girl and watched the queer lunar scenery hurtle past them. The boat, he judged, must be making at least a hundred miles an hour, so his glimpses of the queer, subterranean flora and fauna were but cursory. The phosphorescent vegetation with its eerie luminosity persisted as league after league of the winding stream was left behind them. Gigantic flying reptiles sometimes darted downward at the boat, but invariably underestimated its great speed, striking the water from one to two hundred feet behind it, then rising to flap lazily and disgustedly away in search of other less elusive quarry. After they had traveled in this manner for nearly six hours the helmsman suddenly reversed his power, bringing the craft to a stop before two huge, heavily barred gates which extended from the bottom of the stream to the surface of a great arch of masonry that marked the beginning of a tunnel.