"The mischief!" exclaimed Dave bending to levers and starting the Monarch II forward at best speed.

Hiram sat staring. He blinked, half-blinded. The machine was irradiated in clear, sharp outlines as the great searchlight glare was focused, a speck of action in the sky.

A chorus of cheers went up from the deck of the steamer as its pa.s.sengers caught sight of the airship. Only for a moment, however, was the brilliant sky picture in view. Dave turned the head of the machine on a volplane sweep, and the searchlight operator could not locate it again.

"Well, we've been seen," observed Hiram,

"I'm sorry for it," replied Dave simply.

"Look there!" cried Hiram abruptly.

Dave had selected a course leading over the land, away from the water. As Hiram spoke, his own eye caught sight of some brilliant sparkles of light.

It was a rocket, exploding in mid air directly in their course, and it was to this that Hiram Dobbs had directed the attention of the young aviator.

CHAPTER XX

ACROSS THE BORDER

"Did you see it?" asked Hiram, in a great state of excitement.

"Yes," responded Dave. "A rocket."

"See! See!" continued Hiram-"there's it second one!"

"Sure enough."

"Dave, this means something."

"For us, you think?"

"Yes, I do. Keep near the place where these rockets were fired, Dave. Now then, what do you think?"

Dave slowed down. There was certainly something to his companion's surmises or suspicions, whatever they were. Directly at the spot whence the rockets had been fired there now suddenly flared up a great reach of flames.

Watching these, the interested aviators saw them change to a reddish hue. Three times, at brief intervals, they did this.

"Don't you see?" persisted Hiram.

"See what?" asked Dave.

"A signal."

"You think so?"

"I surely do. Now, then, look sharp. There are figures about the fire. The fire is pitch or oil, or something that could be made to flame up quickly. One of the men threw something into it from a box. It was red fire."

"Why, yes," observed Dave slowly. "I'll admit that was some kind of a signal."

"For the airship," interrupted Hiram quickly. "Look, look again, Dave! One of the men is shading his eyes from the glare of the fire, and is looking straight up into the sky. Why, it's plain as day. They saw our airship when that searchlight caught us. They were waiting for an airship to come along."

"Another airship than ours, you mean?"

"That's it, and I'll bet the Drifter! They took ours for the Drifter. They want us to land. Why, see there, one of the fellows is looking through a field gla.s.s--as if he could make us out in the dark away up here!"

It did not take Dave long to drift to Hiram's way of thinking. The spot where the fire showed seemed to be a large yard of some kind, attached to a factory.

"Of course this is all guess work, Hiram," said Dave, after a moment's thought. "Just the same, it fits in to your theory."

"Say," spoke Hiram suddenly, "I've an idea."

"What is it, Hiram?"

"Make a stop just as soon as you can."

"What's that for?"

"Let me out, and give me a chance to find out who that signal was intended for."

"I declare, it's not a bad plan," said Dave at once.

"Can't you find some safe place where we can land?"

"There won't be much trouble about that."

"Do it, Dave," urged Hiram, "and right away, so I won't lose track of the place yonder."

Dave inspected the country below as closely as he could at a distance. He circled to a lower level, and selected a patch of high gra.s.s between two corn fields.

"Now then," announced Hiram. "I'm off."

"I shall wait anxiously for your return, Hiram."

"Don't worry, I shan't get into any trouble."

Dave did not leave the flying machine. He kept himself in readiness for a flight, should anyone approach the spot. There was not much fear of that, though, he reasoned, as the place was away from the traversed roads and paths.

The young aviator had quite a spell of waiting. He began to fear that Hiram had lost his way or that something had happened to him, as an hour pa.s.sed by. Suddenly, however, his active young a.s.sistant bounded into view, chipper and lively as usual.

"What news, Hiram?" inquired Dave.

"The best in the world."

"You have found out something?"