ing his airships. The propeller was now a blur of light. The explosions of the motor became a steady roar, the noise from one cylinder being merged into the blast from the others so rapidly that it was a continuous racket.
With a whizz the monoplane shot across the ground. Then, with a quick motion, Tom tilted the lifting planes, and, as gracefully as a bird, the little machine mounted upward on a slant until, coming to a level about two hundred feet above the earth, Tom sent it straight ahead over the roof of his house.
"How's this, Rad?" he cried. "Isn't it great?"
"It—it—er—bur-r—r—r! It's—it's mighty ticklish, Massa Tom—dat's de word—it suah am mighty ticklish!"
Tom Swift laughed and increased the speed. The Butterfly darted forward like some hummingbird about to launch itself upon a flower, and, indeed, the revolutions of the propeller were not unlike the vibrations of the wings of that marvelous little creature.
"Now for some corkscrew twists!" cried the young inventor. "Here we go, Rad!"
With that he began a series of intricate evolutions, making figures of eight, spirals, curves, sudden dips and long swings. It was master-work in handling a monoplane, but Eradicate
