"We certainly are going up!" mused Tom, as he noted the needle of his height gage showing an alt.i.tude of twelve thousand feet. "When are they going to stop? We're high above the clouds now."

That was true as regarded himself, Jack, and two other French planes.

But still the Germans climbed. Doubtless some of them were engaging the big machine which was low down, trying to take photographs, but Cerfe and Boughton were guarding that.

"Here comes one at me, anyhow!" thought Tom, as he saw a Hun machine headed for him.

"Well, the sooner it's over the better. Here goes!" and he pressed the release of his automatic gun, meanwhile heading his craft full at the German to direct the fire, for that is how the guns are aimed in a Nieuport, the gun being stationary.

And so began the battle above the clouds.

CHAPTER XIX

QUEER LIGHTS

Tom Raymond's first few shots went wild, as he noted by the tracer bullets. Then, steering his machine with his feet, he brought it around a trifle, and, having by a quick action risen above his antagonist, he let him have a good round, full in the face. The result was disastrous to the German, for suddenly the Hun machine burst into flames, the gasolene from the punctured tank burning fiercely, and down it went a flaming torch of death.

Tom felt some bullets whistle around him, and one exploded as it struck part of his engine, but without injuring it.

"Explosive bullets, are they?" mused the young aviator. "Against all the rules of civilized warfare. Well, he won't shoot any more," he thought grimly.

But though Tom had come victorious from his engagement with his single antagonist, he had no sooner straightened out and begun to take stock of the situation, than he became aware that he was in great danger. Above him, and coming at him with the swiftness of the wind, were two speedy German machines, bent cm his destruction.

They were both firing at him, the angles of attack converging, so that if one missed him the other would probably get him.

"I've got to get out of this," Tom reasoned. He headed his plane toward the antagonist on his right, shooting upward and firing as rapidly as he could, and had the satisfaction of seeing the German swerve to one side.

The fire was too hot for his liking.

The other, however, came on and sent such a burst of fire at Tom that the latter realized it was a desperate chance he was taking. He tried to get above his enemy, but the other's plane was the speedier of the two, and he held the advantage.

Tom's ammunition was running low, and he realized that he must do something. He decided to take a leaf out of the book of the Germans.

"I'll go down in a spinning nose dive," he reasoned. "They'll be less likely to hit me then. I'll have to go back, I guess, and get some more shots. I used more than I thought."

He sent his last drum at the persistent German, and, noting that the other was swooping around to attack again, went into the dangerous spinning nose dive.

The Germans may have thought they had disabled their antagonist, for this dive is one a machine often takes when the pilot has lost control.

But in this case Tom still retained it, and when he had dropped out of the danger zone, he prepared to straighten out and fly back over his own lines.

It is not easy to straighten an airplane after such a dive, and for a moment Tom was not sure that he could do it. Often the strain of this nose dive, when the machine is speeding earthward, impelled not only by its propellers, but by the attraction, of gravitation, is so great as to tear off the wings or to crumple them. But after one sickening moment, when the craft seemed indisposed to obey him, Tom felt it beginning to right itself, and then he started to sail toward the French lines.

He was not out of danger yet, though he was far enough away from the two German machines. But he was so low that he was within range of the German anti-aircraft guns, and straightway they began shooting at him.

To add to his troubles his engine began missing, and he realized that it had sustained some damage that might make it stop any moment. And he still had several miles to travel!

But he opened up full, and though the missing became more frequent he managed to keep the motor going until he was in a position to volplane down inside his own lines, where he was received with cheers by his comrades of the camp.

"How goes it?" asked Major de Trouville anxiously.

"I think we are holding them off," said Tom.

He was the first one who had had to return, much to his chagrin. He leaped out of his craft, and was about to ask for another to go back and renew the battle of the clouds, when he saw the big photographing machine returning, accompanied by all but two of the escorting craft.

"A pair missing," murmured the major, as he searched the sky with his gla.s.ses.

And Tom wondered if Jack's machine was among those that had not headed back.

Eagerly he procured a pair of binoculars, and when he had them focused he identified one machine after another, at last picking out his chum's.

It did not seem to be damaged.

But two of the French craft had been brought down--one in flames, the report had it, and the other out of control, and both fell within the German lines.

"Did you get any photographs of the big gun?" asked the major, when the men in the double machine had made a landing.

"We got lots of views," answered the photographer, "but what they show we can't say. As far as having seen the gun goes, we didn't spot it."

"Well, maybe the photographs will reveal it," suggested the major. "Ah, but I am sorry for the two that are lost!"

Jack's experience had been less exciting than Tom's. One machine had attacked the former, and there had been a hot engagement for a while, but the German had finally withdrawn, though to what extent he was wounded or his machine damaged Jack did not know.

However, the picked squadron had reason to feel satisfied with their efforts. All now depended on the developing of the photographs, and this was quickly done. For this part of warfare is now regarded as so important that it is possible for a plane to fly over an enemy's station, take photographs and have prints in the hands of the commanding officer inside of an hour, if all goes well.

Carefully the photographs were examined by men expert in such matters.

Eagerly they looked to discover some signs of the emplacement of the big gun. But one after another of the experts shook his head.

"Nothing there," was the verdict.

"Then we've got to try again," decided Major de Trouville. "We must find that gun and destroy it!"

"Well, we're ready," announced Tom, and the others of the picked squadron nodded in a.s.sent.

And then began an organized campaign to locate the monster cannon. It continued to fire on Paris at intervals. Then three days went by without any sh.e.l.ls falling, and the rumor became current that the gun had burst.

If this had happened, there was another, or more, to take its place, for again the bombarding of the city began.

Meanwhile the air scouts did their best to find the place of the firing.

Hundreds of photographs were taken, and brave scouts risked death more than once in flying low over suspected territory. But all to no purpose.

Several were killed, but others took their places. Jack was. .h.i.t and so badly wounded that he was two weeks in the hospital. But when he came out he was again ready to join Tom in the search.

No word came as to the whereabouts of Bessie and her mother, nor did Tom hear anything of his father. The lack of information was getting on the nerves of both boys, but they dared not stop to think about that, for the army needed their best efforts as scouts of the air, and they gave such service gladly and freely.

Every possible device was tried to find the location of the German gun, and numerous battles above the clouds resulted at different times during the scout work.

On the whole the advantage in these conflicts lay with the armies of the Allies, the Germans being punished severely. Once a German plane was brought down within the French lines, and its pilot made a prisoner.

It was hoped that some information might be gotten out of the German airman that would lead to the discovery of the big gun, but, naturally, he did not reveal the secret; and no more pressure was brought to bear on him in this matter than was legitimate. The hiding place of the gun remained a secret.