In this fashion they gradually cut down the space separating them from the object of their concern. Tom it was this time who made a discovery.
He came to a stop, and putting his head close to that of his chum whispered in his ear:
"We're in great luck, Jack. I can make out two cars standing in the road before the chateau. The general must be holding a regular council of war up here, to settle some big matters."
"He'll settle them, all right, believe me," muttered Jack. "But it'll have to be a scuttle policy. Those Huns are licked, yes, licked good and hard. They're just beginning to know it, too. We're proving too much for their backbone to stand. Well, two cars means we're going to have a double chance to get our little bucket filled with the juice, Tom."
"Seems like it," was all the other allowed to pass his lips, as he once more commenced to advance.
They kept to the side of the road. Here trees were growing, and while the leaves were coming down fast after a frost, at the same time plenty still remained capable of affording shade in the daytime and making shadows at night.
Under the trees they could glide along without much danger of detection in case a sentry had been posted in front of the chateau. Both boys looked sharply again, striving to find out whether either of the military cars had an occupant.
So far as they could see, this did not happen to be the case, although cautious Tom would not wholly believe it until he had looked further.
Wearied by the long wait, the drivers might have gone to sleep inside the closed cars.
Like a couple of creeping ghosts the air service boys now advanced. The cars stood close together, facing the same way, which Jack considered a lucky thing for their designs.
Tom pressed him back as if to bid him wait, pail in hand, while he took upon himself the task of learning what they might expect. Making his way to the nearest car he peeped in. To his satisfaction there was no occupant. Repeating his action he ascertained that the second car also was empty.
So he gave a low chirp. Jack recognized an old signal, often used between them in days past. It meant he could come on without fear of trouble. And Jack, eager, as he was, to secure some of the petrol, did not linger a second longer than was absolutely necessary.
"Let's get busy, Jack," his chum told him, as he came up behind the nearest car. "I'll keep watch, and you try your hand at cribbing some of their gas juice."
While Jack did not claim to be an expert at the business of transferring petrol from one tank to another, or into a gaping vessel, he believed he would be able to manage. They must get what they needed, if not one way, then through other means. Necessity knows no law, and their very lives, certainly their liberty, was placed in peril by this impotence on the part of their plane.
Jack kept mumbling softly to himself as he worked. He seemed at first to meet with considerable difficulty, judging from the tone of his muttering. In fact, Tom had even turned to offer his assistance when he plainly caught the gurgle of running fluid and immediately sniffed the air strongly impregnated with the odor of petrol.
That told the story. While Jack continued to grumble he was actually acquitting himself with credit. So Tom chose not to interfere, but allowed his comrade to finish the work.
Once he thought he heard a gruff voice from somewhere over the wall of the chateau. He even feared they would be interrupted by the coming of the chauffeurs, who may have received word from their masters that a start was about to be made.
This, however, greatly to Tom's relief, proved to be a false alarm, for no one appeared. But there was Jack muttering again.
"Got every drop of juice this tank holds, Tom, and still not as much as I'd like to carry back. Shall I tackle the other car? I'd like to clean both of 'em out while about it, even if I have to waste some. Might save us heaps of trouble later on, if they were stalled here."
"Please yourself, but hurry above all things," Tom begged him.
"Just getting the hang of things now, and the second one will go a lot better than the first," Jack assured him.
Finally the work was accomplished. Jack seemed proud of his ability to purloin the badly needed stock of petrol. He chuckled as he turned to Tom to announce that he was through.
"Oh, me! Oh, my! But won't there be a hopping mad crowd around here when they find out that their gas tanks are both empty? By then I hope we'll be merrily on our way to camp, able to snap our fingers at the raging Boche, and with a little passenger aboard our plane. Back to the graves for us it is, Tom. Time for all spooks to climb into their holes again and disappear."
"Keep quiet, can't you, Jack!" whispered Tom. "You'll queer the whole business yet if you don't watch out. Come on, and don't leave a trail of gasoline to help them follow us."
The air service boys turned their backs on the chateau, but Jack hoped it would be only a temporary absence for them. He was already beginning to worry about something else, and of course could not keep his troubles to himself very long. Consequently when they were about half way back he again broke out.
"Just happened to think of a thing that's going to bother us some, I'm afraid, Tom," he suggested.
"What now?" demanded the other.
"If we chuck this stuff into our gas tank, why, out she's bound to pour through those two holes the bullet made, and that's a fact, Tom."
"Is that all?" asked the other indifferently. "I've got everything handy to repair those holes in almost two shakes of a lamb's tail. You leave it to me, Jack."
"You better believe I will, and mighty glad of the chance. Why, do you know, just the idea scared me stiff. But I do remember now that you always make it a point to carry along several wooden plugs and some wax calculated to make an air-tight joint. With that outfit you can soon have the tank plugged so it won't leak a drop. Bully for you, Tom!"
"I should have looked after that before we left the plane," admitted Tom. "But the fact was I wanted to take a turn around first; and then when we struck the road it sort of led us on and on. But it's all right, Jack."
CHAPTER XXI
AT THE OLD CHATEAU
THE air service boys had no difficulty in retracing their steps, especially since Tom, with his usual caution, had been careful to remember the spot where the main road was joined by that coming from the country cemetery.
Once again they made their way past the ghostly looking stones.
"I can see our boomer now, Tom!" Jack cried, as if he had been a little afraid that something had happened while they were absent, and that they would find the airplane missing.
"You want to be mighty careful of that stuff," his chum warned him, as Jack stumbled over some unnoticed object, and only retained his balance by a supreme effort.
"That's a fact," mumbled the other. "Especially as there's no more where this lot came from. I attended to that, all right. But here we are, and now to get the holes plugged up."
"At last my time to make use of that little outfit has arrived!" Tom exclaimed. "I've carried it for months, thinking I'd need it badly some day or other. Well, that time is on us, and this repays me for all my trouble. Set that pail down, and be ready to lend a hand, Jack."
He fumbled in a pocket of the body of the plane, producing a small roll, which, upon being opened, disclosed several plugs of soft wood, such as might easily swell if moistened. There was also some wax, the kind fruit growers use in grafting new scions on old trees.
Tom carefully examined one of the holes in order to learn its exact dimensions.
"Just as I expected, it's perfectly round in shape, which makes it easier to plug up," he announced, pleased with his discovery.
A minute later he had fitted one of the wooden pegs in tightly. Then he used the wax, which was just hard enough for his purpose.
"That one is finished, and I think it will hold fairly well," he remarked, somewhat to the surprise, as well as delight, of his companion, who had anticipated that it would take much longer.
"You're a sure-enough wizard, all right, Tom," was his gratified comment. "Why, you're getting things put through in a jiffy. But I hope there isn't any danger of the petrol acting on the wax, and causing a quick leak."
"I've tested it, and feel certain it will hold for an hour or so, anyhow, Jack. And by then we ought to be back in camp."
"Will, if we have any luck at all," asserted Jack.
"Now I'll get busy on the other hole," continued Tom. "Though that isn't so important, as it's at the top of the reservoir. Still, it might be just as well to close it up in order to avoid waste. Besides, there's always danger of an explosion if your tank sprinkles this deadly stuff around."
Jack took occasion to step aside to where he could look up between the trees and glimpse the dimly seen chateau, knowing now just where to look for it. When he came back he had information to impart that he thought would please Tom.