"Come," spoke Dave simply, and sprang into his seat in the Machine. Hiram hastily collected their few belongings scattered about the spot. He bundled them into the accommodation basket, and was in his place almost as soon as Dave. The eyes of both of the young aviators were fixed on a rapidly approaching object--an airship. Dave did not have to glance at its construction more than once to know definitely that it was the stolen Drifter. Whoever was at the levers, Jerry or his father, thoroughly understood his business, Dave saw that. The aero-hydroplane came rather abruptly into view over a wooded hill top, and was rapidly approaching them. "You see, I was right," said Hiram hastily. "That half breed was a spy, at least to that crowd. He has directed them here." "All ready," ordered Dave, in a set, sturdy tone, and the self starter began to work. "What is it--a chase?" fluttered Hiram. "We'll have to wait and see. You know what kind of fellows the Dawsons are. I'm not going to sit like a bird in a nest and have them swoop down upon us, though." "There are three--you can count them in their airship," said Hiram, shading his eyes and craning his neck. "Four," corrected Dave. "The Drifter has a capacity of five ordinary people, Mr. Randolph told me." The Monarch II made a magnificent slanting rise up into the air. Dave knew the splendid qualities of the machine under his control. They included an ability for a quick light ascent. He had no idea of the purpose of the Drifter crowd, but of course their main object was to capture their rival. The question was, failing in this, how, far would they go in the way of crippling or even destroying the Monarch II. The Drifter was headed on a course directly towards the eminence which the boys had just left behind them. There had come up an eight hour wind about noon, and Dave knew that would be child's play maneuvering to avoid the enemy intent on annoying or injuring them. He drove ahead at a six hundred feet level and waited for the Drifter crowd to indicate what their purpose was. "They are changing their course!" said Hiram quickly, as the Drifter wheeled suddenly. "They are going to try a new ascent," explained Dave. "Why?" "To get to a higher level than ourselves." "Then they mean mischief?" "I am afraid that they do," replied the young aviator. "Maybe they are trying to scare us," suggested Hiram. Dave was now certain that the purpose of the Dawsons was to pursue, capture or intimidate them, or drive them away. They had a superb machine, and as they made a far lateral shoot it brought them considerably higher up than the Monarch II. In fact, after one or two circles, like a huge bird swooping after prey, the Drifter came almost directly over them.