So the minutes pa.s.sed. Other pilots had already ascended to await the a.s.sembling of the picked squadron at some given alt.i.tude. Every minute or two could be heard the rush of some unit starting forth. There were few of the accompaniments of an ordinary ascent, for all loud cries had been banned.

"All ready!" came the welcome words at last.

The last strut had been carefully gone over, and now everything was p.r.o.nounced in perfect condition. At the same time, after such a discovery had been made, it was only natural for the boys to feel a queer tug in the region of their hearts as they climbed to their seats, and with hands that quivered a little proceeded to make fast the safety belts.

"There goes another bomber, which makes four--the full number you spoke of, Tom," remarked Jack. "I suppose we're holding up the procession more or less, worse luck, when usually we can be found in the lead."

"The commander must know about our mishap," replied Tom, "and isn't apt to blame us for any little delay. The night's still young, and we can reach our destination in half an hour, with time to spare. So cheer up, old comrade; everything's lovely and the goose hangs high.

Now we're off!"

With that he gave the word, and paid attention to his motor, which started a merry hum. The propellers commenced to spin, and down the slight slope they ran with constantly increasing speed. All around them could be heard the refrain of planes in action; from above came similar sounds, and Jack, looking up, discovered dim scurrying forms of mysterious shape that flitted across the star-decked sky like giant bats.

Now they, too, were rising swiftly in spirals. Both kept a keen watch, for it was at this time they stood the greatest chance of taking part in an unfortunate collision that might result in a fatal disaster.

But every pilot was on edge, and careful to avoid any such blunder. They had been well drilled in all the maneuvers connected with just such a hurried ascent in numbers. Each plane had its regular orbit of action, and must not overstep the bounds on penalty of the commander's displeasure.

After mounting to the arranged height, the Air Service Boys found that it was a very animated region, though fully a thousand feet from the earth's surface. Almost a dozen planes in all were moving in a great circle, their motors lazily droning, and the pilots ready to enter into squadron formation on signal.

In fact, Tom and his chum were the last to arrive, which under the circ.u.mstances was not to be wondered at.

"All on deck, I reckon," called out Jack, after he had taken a survey about him. "There's the signal from the flagship, Tom. We've got to keep the red lantern ahead of us and fall into line. There go the bombers to the center, and our place you said was on the left, tailing the whole bunch."

Like a well disciplined aerial navy they fell into place, each taking its position as previously arranged. When the formation was made complete another signal was given. This meant the advance was now to begin, and the crossing of the German lines undertaken.

Unless there chanced to be some mistake made concerning the proper alt.i.tude required, so as to clear all possible bombardment when over the Hun lines, this might be accomplished without danger. So far as was known, they had gauged the utmost capacity for reaching them possessed by the German anti-aircraft guns, and Jack promised himself to jeer at the futile efforts of these gunners to explode their shrapnel sh.e.l.ls close to the speeding armada.

Something must have been underrated, however; and, in fact, few plans can be regarded as absolutely perfect. The advancing raiders were pa.s.sing over the enemy front when a furious bombardment suddenly burst forth below.

Jack could see the spiteful flashes of the numerous guns, and while the sound of the discharges came but faintly to his ears, to his consternation, all around them, as well as above and below, came sharp crackling noises, accompanied by bursts of dazzling light.

They were actually in the midst of a storm of bursting projectiles and in immediate peril of having some damage done to their swift-flying planes such as would spell ruin to the enterprise, perhaps bring instant death to some of the fliers!

CHAPTER VI

STRIKING A BLOW FOR LIBERTY

"Climb, Tom! Climb in a hurry!"

Jack Parmly shrilled these words close to the ear of his chum. Really, there was no need of his saying a single word, since the pilot had sensed their immediate danger just as quickly as had Jack himself. Already Tom was pulling the lever that would point the nose of their aerial craft upward toward the stars, and take them to a much loftier elevation.

The experience was very exciting while it lasted, Jack thought. He saw the numerous planes, forming the raiding squadron break formation in great haste, each pilot being eager to dodge the bursting sh.e.l.ls and seek an elevation where they could not reach his flimsy craft.

It would take only one accidental shrapnel sh.e.l.l to cause the destruction of the best machine among them, and thus reduce the number of available airmen serving the cause of liberty.

For a brief interval the explosions continued to sound all around them.

But presently Jack was enabled to breathe easily again. They had climbed beyond the range of the German guns, no matter how heavily charged; and, besides this, they sped along rapidly, so that the Hun lines were soon left behind.

"Trouble's past. Admiral signaling keep on this level, Tom!" called out the observer.

"Got you, Jack!" came the answer, heard above the rushing noises that "made the welkin ring," as Jack told himself.

The firing ceased as the German gunners realized, to their chagrin doubtless, that again their intended prey had eluded them. They must have set those anti-aircraft quick-firers of theirs in fresh elevated emplacements after the Yankees had taken the measure of their power to do harm; but the trap, if such it was intended to be, had failed to catch a single victim.

"Did they get any of our crowd?" Tom called out, feeling considerable uneasiness as to the result of the bombardment.

"Never touched us," he was immediately a.s.sured by the observant Jack.

"All the same it was a smart trick, and somebody's bound to be hauled over the coals on account of the blunder."

"Yes," admitted Tom, speaking loud so as to be heard above the roar of the numerous planes around them, "because it might have played hob with the squadron, and even ruined the success of the whole expedition."

After that they relapsed into silence. It was exceedingly difficult to try to keep up any sort of conversation while going at such a furious pace through the upper air currents. Besides, the night was cold at such an elevation, and consequently both boys had their heads well m.u.f.fled up, making use of hoods with goggles for the purpose. They also wore gloves on their hands, as well as heavy sweaters under their leather-lined coats.

The formation, in a way, reminded Jack of many a flock of wild geese that he had seen flying north or south over Virginia in their spring and autumn migrations. In the lead went the battleplane containing the squadron commander, forming the apex of the triangle, and showing a fiery red eye in the shape of an automobile rear light as a rallying point for all the other machines.

Then the seven other battleplanes sank away from the apex, three on one side and four on the other, that of the Air Service Boys being the one to the rear of all the rest.

Flying two and two abreast, and guarded on both sides by those st.u.r.dy fighting craft came the four huge bombers, each heavily laden with the most destructive of explosives. They, too, could show teeth if cornered and compelled to depend on their own defensive powers; for each of them carried a machine gun, of which the observer had been trained to make good use, just as he must know how to drop his bombs successfully when the proper instant arrived.

All seemed quiet just at present, but none of those guiding the aerial racing craft deceived themselves with the belief that this could last long. It went without saying that the Huns must realize the necessity for guarding the important bridge across which their beaten armies were flocking day and night in constantly increasing numbers. Unless the guns could be taken across in safety, they stood to lose many of their best batteries.

Consequently they would be apt to a.s.semble a flotilla of fighting planes in that vicinity, ready to soar aloft and give furious battle to any Allied squadron venturesome enough to make the attempt at destruction.

If the blowing up of the bridge could only be accomplished, the sacrifice of a few planes with their crews might be counted a cheap price to pay for the great benefits reaped.

The minutes pa.s.sed, and all the while the raiders were drawing nearer and nearer their intended goal. Every pilot and observer in that squadron had been carefully selected with a view to his fitness for the gigantic task that had been laid out for accomplishment.

There would be no hesitation when the eventful moment came, since none was present save those who had been tried in the furnace of battle and found to be fine gold, eighteen carat pure. Such a thing as flinching when the test came was not to be considered; they would carry through their appointed tasks or fall while in the endeavor, paying the price the airman has ever had dangled before his eyes.

Jack was using his night-gla.s.s, and he now broke out with a cry.

"We must be getting close to the bridge, Tom! I can see flickering lights darting about, and I believe they must be planes rushing up into the air!"

"Like as not they've been warned of our coming by the row we're making,"

replied the pilot, in a shout. "Then again those Huns along the line would send word back, for they must know what we're aiming at. It's all the same to us. We came out after action, and we'd be terribly disappointed if we didn't get a lot of it."

Then came signals from the leading plane. Closer formation was the rule from that time forward, since the bombers must be amply protected in order to allow their gunners an opportunity to get to work with those frightful explosives and hurl them at the place where the bridge was supposed to lie.

Both boys began to feel their pulses thrill with eagerness, as well as excitement. Looking down, Jack could detect moving lights, the source of which he could only speculate upon. Then came a flash which must mark the discharge of the first anti-aircraft gun. The enemy was showing exceeding nervousness, for as yet the leading American plane could not be anywhere within range.

With the burst of shrapnel there came a realization that the gunners below were only trying to get their range. The whole pack would break loose in another minute or less; but Jack had reason to believe their alt.i.tude was such as to render the fusillade harmless.

Then down below he saw a sudden brilliant flash. That must mark the falling of a flaming bomb, dropped from one of the big planes in order to get a lead on their location. Jack believed he had even glimpsed the bridge itself in that brief interval. How the prospect thrilled him!

Tom, on his part, had little opportunity to observe anything that was taking place earthward. His duty lay closer at hand, for he knew that a swarm of fighting Gothas had started up to engage the attacking squadron, and realized that one or more of these hostile aircraft might suddenly appear close at hand, bent on bringing about their destruction.