If you have ever seen a kite come down when the wind has died out, you will understand exactly what this "sifting" is. It means gliding downward in a series of acute angles. The first alarm over, all was now serene aboard Dick's airship. The attempt to start the motor had been given up, and under the supervision of Mr. Vardon the two cadets, Innis and Paul, took turns in bringing the craft down with the engine "dead." The aviator and his helper had had experience enough at this. "Say, this is something new, guiding as big a ship as this without power," remarked Innis, as he relinquished the wheel to Paul. "It sure is," said tile latter. Then, a little later, he called out: "I say, somebody relieve me, quick. I believe I'm going to bring her down in that creek!" They all looked ahead and downward. The Abaris, surely enough, was headed for a stream of water. "Perhaps you'd better handle her," said Dick to the builder of the craft. "We don't want her wrecked before we at least have a START after that prize." Mr. Vardon nodded, and took the wheel from Paul. A few seconds later he had brought the craft to the ground within a few feet of the edge of the stream. Had it been a wider and deeper one they could have landed on it by using the hydroplanes, but the water seemed too shallow and full of rocks for that evolution. And so skillfully had Mr. Vardon manipulated the planes and levers that the landing was hardly felt. A number of specially-made springs took up the jar. "Well, we're here!" exclaimed Dick, as they all breathed in relief. "Now to see what the trouble was." "And we've got a long walk back home, in case we can't find the trouble," sighed Innis, for he was rather stout, and did not much enjoy walking. They had come down several miles from Hamilton Corners. "Oh, we'll get her fixed up somehow," declared Dick, with confidence. Quite a throng had gathered from the little country hamlet, on the edge of which the aircraft had descended, and they crowded up about the Abaris, looking in wonder at her size and strange shape. Mr. Vardon lost no time in beginning his hunt for the engine trouble, and soon decided that it was in the gasolene supply, since, though the tank was nearly full, none of the fluid seemed to go into the carburetor. "There's a stoppage somewhere," the aviator said. The fluid was drawn off into a reserve tank and then the cause of the mischief was easily located. A small piece of cotton waste had gotten into the supply pipe, and completely stopped the flow of gasolene. "There it is!" cried the aviator, as he took it out, holding it up for all to see. "I wonder if anyone could have done that on purpose?" asked Dick, looking at his chums, reflectively. "You mean--Larson?" inquired Jack Butt. "He's capable of anything like that." "But he wasn't near the machine," said Paul.