With a whirr like the wings of a partridge as it is flushed out of the grass by the huntsman's dog, the small machine shot forward a few feet over the smooth ground, then gracefully arose in the air and started away toward the opposite corner of the field. As it proceeded it continued to rise, until it reached a height of possibly ninety or a hundred feet, when it began to dip unsteadily. "It's a gust of wind striking it," remarked John uneasily. "I hope she weathers it. If there was only a pilot in her now, he could----" But even as he spoke the Sky-Bird seemed to recover her balance. Making a pretty circle, away she sped on her course, neither rising nor falling. Like a real bird she sailed onward, the noise of her whirring propeller now lost to her fliers, but her little pale-yellow silk wings against the blue sky plainly tracing her course for them. Paul was running after her now as fast as his legs could carry him. What if she should keep right on and go over the far fence?--he might lose the little darling! That fence was a good half-mile away. For his pet to cover such a distance had not seemed within the bounds of probability to either himself or John at the start, for all of their great confidence in the flying powers of the new model. Now, as he kept on running and the Sky-Bird continued going with no sign of dropping, Paul really became alarmed for her safety in landing. But just before it reached the boundary of the grounds, the youth saw that the airplane was slowly settling. Into the next field it flew, and the high board fence shut it from Paul's view as he came up to it. With a jump he caught the top boards, and scrambled up, springing down on the opposite side. It was to see his little machine just miss the branches of an oak tree and settle down into some long grass about a hundred yards beyond. He found it undamaged, and hurried back to his friends in the fair-grounds, his heart beating jubilantly at the splendid results of the flight. He hugged the small airplane to his heart as if it were the most precious possession in the world, as indeed it was to him. Mr. Giddings and Bob were loud in their praise, and John smiled in that quiet way that told the younger brother how well pleased he was. It was found that the Sky-Bird had passed over the lower fence in just one minute and three seconds, which was certainly good speed for such a diminutive contrivance. Several other flights were then made, all of which were equally successful. At the conclusion Bob Giddings was so excited that he could hardly stand still. "Dad, isn't this little thing simply a wonder?" he exclaimed. "I'd give anything in the world if I could own a big fellow built on this principle. I'll bet it would pass anything now made." His father looked thoughtful for a moment. Then, turning to the Ross brothers, he observed: "Do you think, boys, that these features could be successfully applied to a full-sized airplane?"