"What's that below, Hal?" The speaker was Chester Crawford, an American lad of some 16 years. Hal Paine allowed his eyes to turn from the steering wheel and glanced over the side of the flying a roplane. "I don't see anything," he replied, after a careful scrutiny below. "Neither do I, now," said Chester, straining his eyes. At this moment the third occupant of the machine made his presence known. "Woof Woof " he exclaimed. The third speaker was...