was looking for something else just then. Although they were flying at such a great height, he fancied that the present security would hardly last. The Germans were only waiting until they had gone on a certain distance; then probably a dozen of their hustling little Taube machines would spring upward and chase after the singular stranger like a swarm of hornets, seeking to cut off escape, and hoping by some lucky shot to bring it down.
The barograph was in plain sight from where Frank sat, and perhaps the quick glance he gave at its readings just then had some connection with this expectation of coming trouble.
Billy interpreted it otherwise. He was afraid Frank, thinking they had gone far enough, was sweeping around to start back toward the British trench line.
“Just a little further, Frank,” pleaded Billy. “There’s a big move on over yonder, seems like, where that army is coming along; and I’d like to see enough to interest our good friend Major Nixon when we get back.”
“I don’t know whether I’ll let you say a single word, Billy,” the air pilot told him, as he relinquished the glasses to the eager one. “That wouldn’t be acting neutral, you know. Besides, there are plenty of the Allies’ machines able to fly, and those airmen like Graham-White ought to be able to pick up news of any big movement.”
They could see patches of snow in places, and much water in others where the low country had been inundated by the Belgians. This was done in hopes of hastening the retreat of the invaders, who despite all had stuck to their trenches and the unfinished canal for months, as though rooted there.
All at once there sounded a loud crash not far below the young air pilots, and a puff of white smoke told where a shrapnel shell had burst.
“Frank, they’re firing at us!” exclaimed Billy, who had made an involuntary ducking movement with his head as the sharp discharge burst upon his ears.
Even as he spoke another, and still a third crash told that the Germans had determined the time was at hand to try their anti-aëroplane guns on the strange seaplane that was soaring above the camps.
CHAPTER VII.
THE “SEA EAGLE” ON PARADE
“That means we’ll have to climb higher, so that their guns can’t reach!” Frank immediately decided.
It was indeed getting rather warm around them, Billy thought. The shrapnel puffs seemed to be above, below, and on every side, and it was a wonder that neither of them received a wound.
“Only for the speed we’re hitting up, the story might be a whole lot different, according to my notion, Frank. They have a hard job to get our range, you see.”
“Yes, most of it bursts back of us, showing a faulty figuring,” the pilot explained, as he started a corkscrew movement of the seaplane calculated to cause the aircraft to bore upward in spirals.
The guns, far below, kept up a merry chorus. Billy could hear the faint noise made by the continuous discharges, and the puffs of smoke that seemed to rise in a score of places at the same time told him how eagerly the German gunners were trying to strike that elevated mark.
Now the shrapnel ceased to worry Billy, for he saw that none of it seemed to be bursting around them as before. The limits or range of the anti-aircraft guns had apparently been reached.
“We’re safe from the iron rain up at this height, Frank. What does the barometer say?” he asked, with that spirit of curiosity that had made him a good reporter in the old days.
“That’s too bad,” replied Frank, as he bent forward to look.
“Don’t tell me that the only fragment of a shell that’s struck home ruined our fine barometer!” cried Billy.
“Just what happened,” he was told. “At any rate, it’s knocked to flinders; and I think I must have had a pretty close shave. But we can buy a new one when we get back to Dunkirk. As near as I can give a rough guess we must be between three and four thousand feet high.”
“I should say it was a lot more than that,” Billy declared. “But so long as they can’t reach us any longer, why dispute over a few thousand feet?”
He thereupon once more started to make use of the glasses, and had hardly settled them to his eyes than he gave a startled cry.
“Frank, they’re coming up like a swarm of angry bees!” Billy exclaimed.
“Do you mean Taube aëroplanes, Billy?”
“Yes, I can see as many as six right now in different directions, and others are going to follow, if looks count for anything. The word must have been given to attack us.”
“I’m not worrying any,” Frank told him calmly. “In fact, I don’t believe they’ll try to tackle such a strange hybrid aircraft. They can see how differently constructed the Sea Eagle is from all other hydro-aëroplanes, and expect that we must mount at least one quick-firing gun.”
“Then what are they climbing for, Frank? I can hear the buzz of their propellers right now, and let me tell you it sounds like ‘strictly business’ to me!”
“They are meaning to get close enough to let the pilots see what kind of a queer contrivance it is that’s hanging over their camps,” Frank continued in a reassuring manner. “When we choose to turn tail and clear out, there isn’t one in the lot that can tag on after us.”
“I know that, Frank, thanks to those wonderful motors, and the clever construction of Dr. Perkins’ model. But now here’s new trouble looming up ahead.”
“I can see what you mean, Billy. Yes, that is a Zeppelin moving along down there, one of the older type, I should say, without having used the glasses.”
“But surely it will make for us, Frank. A real Zeppelin wouldn’t think of sheering off from any sort of aëroplane.”
“Watch and see what happens,” Billy was told, as Frank changed their course so as to head straight for the great dirigible that was floating in space halfway between their present altitude and the earth that lay thousands of feet below.
The firing had stopped. Probably the German gunners, having realized the utter futility of trying to reach the Sea Eagle while it remained at such a dizzy height, were now watching to see what was about to take place. Many of them may have pinned great faith in the ability of their aircraft to out-maneuver any similar fliers manipulated by the pilots of the Allies. They may even have expected to see a stern chase, with their air fleet in hot pursuit of this remarkable stranger.
If this were really the case, those same observers were doomed to meet with a bitter disappointment.
“Well, what does it look like now?” Frank asked presently, while his companion continued to keep the glasses glued to his eyes as though fairly fascinated by all he saw.
“The Zeppelin has put on full steam, I should say, Frank,” admitted Billy.
“Coming to attack us?” chuckled the other, though the motors were humming at such a lively rate that Billy barely caught the words.
“Gee whillikins, I should say not!” he cried exultantly. “Why, they’re on the run, Frank, and going like hot cakes. I bet you that Zeppelin never made faster time since the day it was launched. They act as though they thought we wanted to get above them so as to bombard the big dirigible with bombs.”
“And that’s just what they do fear,” said Frank positively. “That’s the greatest weakness of those big dirigibles, they offer such a wide surface for being hit. While an ordinary shell might pass straight through, and only tear one of the many compartments, let a bomb be dropped from above, and explode on the gas bag, and the chances are the Zeppelin would go to the scrap-heap.”
“They’re dropping down in a hurry!” declared Billy. “There, I can see a great big shed off yonder, and it must be this that the dirigible is aiming to reach. We could, however, bombard the shed as easily, and destroy it together with its contents. Frank, it makes me think of an ostrich trying to hide its head in a little patch