Several times Tom turned the propeller around. Then, with a pop, the engine cylinders began to fire, Tom jumped swiftly back, and the propeller whirred like a mad thing. At the same time the Sky-Bird gave a start, as though to dash forward; but beyond a steady, slight vibration of her whole body, as Tom slowed down the motor to four hundred revolutions per minute, there was no indication to her inmates that she was straining to get away. Tom now quietly mounted the step, and came into the cabin, pulling the step up after him and closing the self-locking door. "That shows you how this third ground wheel acts, dad!" cried Bob triumphantly to his father, who sat in a chair adjoining. "Now watch the old girl jump ahead when Paul throws back the brake lever and his brother lifts the third wheel and gives her more gas!" The changes were made even as he spoke; the propeller's hum grew into a mild roar through the cabin walls, and the Sky-Bird leaped away over the ground, gaining momentum at every yard. To the surprise of even two such veteran flyers as John Ross and Tom Meeks, the airplane had gone less than fifty yards when she began to rise as gracefully as a swallow in response to her up-turned ailerons and elevators. In less than ten seconds she was well up over the fair-grounds, and the roofs of all the buildings in the neighborhood were seen below them. John kept the machine mounting at a good angle until the altimeter showed them to be up two thousand feet. Then he straightened out the ailerons and elevators, and began to run on a level keel. The other inmates of the cabin noticed, by looking through the observation windows, that he was gradually bearing in a great circle about the town of Yonkers. Off to the northwestward were the rugged blue crags of the Catskills, covered with patches of milk-white snow, and just in front, winding like a huge serpent among the picturesque foothills, was the sparkling Hudson, dwindling away to a mere silver thread in the north, tapering away in the same manner toward the south, where it lapped the piers of the city of New York and immediately afterward lost itself in the waters of the Upper Bay. Although the great skyscrapers of the big city itself could be dimly seen, they looked very small at that distance. Directly below them our friends could make out the familiar buildings and landmarks of their own town as they swept past one by one, John purposely flying at reduced speed so that a clearer vision could be had. He also shot down to within a thousand feet, presently, as he saw his own home approaching. Someone, whom both John and Paul immediately recognized as their mother, stood in the door waving a handkerchief. In recognition, Paul drew down one of the sliding windows, and put out his head and fluttered his own handkerchief. Shortly afterward--it seemed not more than a minute--the machine was over Shadynook Hill, and Bob and his father were waving a similar salute to Mrs. Giddings.