As much of the success of the latter depended on the work of their flying squads in discovering the hidden machine-gun nests, and betraying their position to the gunners, it stood to reason that the Germans felt an ever growing hatred toward the airmen. Hence that night raid which had been so neatly parried. Yes, Tom could easily believe what his comrade suggested.
"Show me where you saw the sneak, Harry," he pleaded, as they continued to crouch in the semi-gloom; for after that recent attack from the skies almost every light about the aviation field had been extinguished, and they felt obliged to depend on the stars to show them where the various hangars lay.
"Notice that extra high hangar over there," came the soft reply. "That's Beresford's, you know, where he keeps his monster four-man plane. The Huns may have got wind of something unusual, and are plotting to destroy his jumbo aircraft before he smothers them in a fight. There, did you see that again?"
"It was a man slipping across from one shadow to another, as sure as anything," breathlessly admitted the second watcher.
"No fellow would act that way unless he wanted to keep from being seen, would he?" asked Harry.
"You're right there. Oh! I saw a second one follow him then, Harry!"
"Yes, there's a pair of the creepers. That makes me believe more than ever they were aboard one of those bombing planes, Tom."
"It might be they fell when one of the Hun raiding planes was knocked out," suggested the other, as an idea struck him. "Only one went down in flames, I remember now. Those in the other may have managed to make a safe landing, and bent on hitting us a crack before trying to get back to their lines, they've crept into the camp here."
"Carrying some grenades, I'd like to wager, which they can use in kicking up a big row, under cover of which they'll scoot off," Harry went on.
"We must put a peg in their plans then," whispered Tom. "It'd be a shame to let them do what their pilots failed in, and blow up a part of our hangar field here."
"If they do they'll go up with the planes then!" Harry gritted between his set teeth. "Come, let's move on and corner the Huns!"
This suited Tom. Discretion might have caused them to alarm the camp and in this way cause the prowlers to disappear. But ambition, on the other hand, had fired the hearts of the two boys. They saw an opportunity to get in a telling blow by capturing those two spies. It was a chance to gain a little fresh glory, as well as to protect the monster plane of Beresford.
Accordingly they commenced to move forward, bending low and taking advantage of every dense shadow that came in their way. Their objective was the hangar that afforded shelter during the night to the novel and as yet untried monster plane, of which so much was expected, and rumors concerning which might have even sifted into the enemy lines.
Of course both Tom and Harry were keenly on the alert for the first fresh sign of the prowling enemy, whose designs they had set out to balk. Very probably the Huns would resist desperately, and there might be a fight. Tom felt his heart beat tumultuously, but such a thing as fear did not enter into his calculations.
CHAPTER XII
A LIVELY CHASE
"THEY'VE gone," presently whispered Tom, in a disappointed tone.
"Only hiding somewhere near by," Harry assured him, equally careful to lower his voice. "We'll begin to circle around, and presently rout them out. Be ready to jump the first chance you get, and let out a whoop at the same time. It'll give 'em a shock, and start 'em to running. Then we'll soon have a pack on their heels."
"What if they use their trench grenades on us?" asked Tom.
"Not likely to except as a last resort. But we've got to take the chances. Dodge, that's all. Now to swing around the big hangar."
Harry squeezed his companion's arm while saying this. Both of them were fairly quivering with the excitement, just as highly strung race horses can be seen quivering while prancing up and down awaiting the tap of the bell that summons them to the wire for the start.
It was not pitch-dark, but even the possessor of keen eyesight would have had to look closely in order to make certain that a moving object was a human being and not a dog.
Harry's surmise proved to be well founded, for they quickly discovered a suspicious movement close to the large hangar. Yes, the two Hun spies were undoubtedly there, and already busily engaged in doing something that could only mean trouble for the American escadrille.
Closer the pair of watchers crept. They could now hear the men whispering as they worked, and Tom even believed he caught a guttural German word used. This convinced him their theory was founded on fact, and that these were secret enemies in the camp.
Another half minute and he felt Harry nudge him. That meant the other believed the time had arrived for them to make their leap; and when he felt his companion start Tom stirred himself.
Both let out a yell as they sprang forward. Tom more than half expected to hear an explosion, thinking the Huns, on finding themselves caught in the act, would fire their grenades promptly.
Nothing of the kind came about. Instead both men instantly dropped flat and started to roll away with incredible swiftness, as though escape was the first thought in their minds.
Tom hurled himself through space. His intention was to pin one of the spies to the ground and try to hold him there until help came. Their outcries would of course arouse every man within hundreds of yards of the spot, and lights must soon be brought to bear on the scene.
Although Tom's calculations may have been all right, he did not meet with as much success as he had probably anticipated. Perhaps the wary Boche guessed what was coming; at any rate he succeeded in squirming from under, and when Tom landed it was only to feel the other rolling out of his reach.
But he went after him like lightning, bent on attaining his goal.
The Hun was scrambling desperately in the endeavor to get on his feet.
Tom hurled him over, and closed with him. Finding his escape thus cut off, the other commenced to fight like a tiger, clawing and struggling furiously.
They had it "hammer-and-tongs" for a brief space of time. Then Tom slipped and lost his grip, upon which the other rolled over several times, got to his knees, then his feet, and started to run.
But he counted without reckoning on the staying qualities of the American. Tom had always been called a "sticking-plaster" by his fellow players on the football field. He was not to be counted out of the game until the last whistle sounded and the referee's falling hand closed the fun.
So he was after his man with grim determination not to let him get away.
Having gone to so much trouble, and received in addition several scratches in the contest, he meant to keep everlastingly at it.
The Boche dodged to one side, as there were men running toward them, and already several lights had sprung up. Tom was close at his heels, and gaining rapidly, being spurred on by an ambition to complete the good work he and Harry had started.
He saw the spy glance back over his shoulder. The situation must have appeared very grave to the other, who could expect to meet with short shrift if caught in the act of trying to destroy the hangars and planes of the American aviators in this bold fashion.
Just then Tom saw the man raise his arm. Guessing what he intended to do, the Yankee air pilot dodged just in time. Some object went hissing past, close to his head. An instant later there was a loud explosion in his rear that seemed to make the very air quiver.
Of course the Boche had hurled a grenade with the intention of making further pursuit on the part of his persistent adversary impossible.
Tom hoped that was the extent of his supply of such ammunition, for he might not be quite so successful in avoiding the bomb another time.
Again was the fleeing spy compelled to whirl aside because of threatening peril ahead. Dodging in and out between the khaki-colored canvas field hangars he sought desperately to throw Tom off his track; but no hound ever followed its quarry with more pertinacity than the Yankee air pilot followed now.
Then something happened. Tom came in collision with a runner, so that the two of them fell headlong to the ground. By instinct Tom hugged the other in his arms. He suspected on the spur of the moment that this might be the other spy, trying to elude Harry, and cutting across his track by the merest chance.
The fellow struggled furiously, but Tom managed to get a good hold on him, and kept it tenaciously. As the other was also clutching him his further pursuit of the fleeing spy seemed doomed to failure; and so Tom felt that the only thing left was to make sure of this party.
"Hey, Tom, let go! You're choking me!" came a voice that electrified him, and caused him to release his clutch.
After all it was Harry upon whom he had fallen, Harry who having lost all track of his man was rushing wildly this way and that in hope of once again getting in touch with the fellow.
"Quick, before it's too late, join me!" shrilled Tom, scrambling to his feet again as best he could, and feeling angry because of this ridiculous accident. "There he goes, Harry! After him again!"
So they both started once more to run at top speed. The agile spy had been able to put considerable distance between them while his pursuers struggled on the ground, and seemed likely to escape. But there was one thing that stood in his way.
Men were running this way and that in every direction, calling to one another, and trying to understand what all the row was about. A squad of oncoming hostlers blocked his passage. They evidently were beginning to get light on the situation, for discovering the panting runner they now set up a concerted shout.