“If they blow up a bridge, and wreck a train loaded with millions of dollars’ worth of stuff, and it’s proved that the scoundrels passed over from our side of the border, Uncle Sam will have to pay the whole bill?” questioned Tubby, now becoming aroused in turn.

“No doubt of it, if the proof is forthcoming,” Rob assured him serenely, since he knew enough of treaties and international law for that.

“Then anything that’s done against Canada from our side is really a blow aimed at our own country?” questioned Andy, beginning to show signs of anger. “Why, if it stands that way, then those conspirators are just as bad as if they were trying to knock a big hole in the U. S. Treasury, from which untold oodles of money could drop out. They’re breaking the neutrality laws smack. I’d like to let ’em know just what I think of such sneaks. There ought to be some way to detect and punish such backhanded knockers.”

“Oh, there are plenty of ways!” asserted Rob. “The law is stern enough, if you only can catch them in the act. There’s the rub. They take all sorts of precautions to hide their identity. Who could recognize that chap up a mile or so from the earth? How does any one know that he’s meaning to drop lower presently, so as to take a lot of pictures of the railroad where it passes over a bridge or trestle?”

“Is that the way it’s done?” ejaculated the deeply interested Andy, who was more or less ignorant of how air pilots make themselves so useful in war times.

“Watch him!” snapped Rob, and all eyes were again focussed on the far distant object moving across the heavens, and passing some fleecy fragment of a floating white cloud.

“As sure as anything he’s dropping on a regular toboggan slant!” cried Andy, thrilled by the sight.

“Huh!” remarked the wise Tubby, with the pride of superior knowledge, “that’s what they call volplaning. Sometimes an aviator will shoot down for a mile like a streak of lightning, and just when you think he must be smashed against the ground he’ll suddenly stop, just like a descending eagle does, and sail away as nice as you please on a lower level.”

“Which is exactly what that spy is doing right now!” exclaimed Andy. “I guess he is down far enough for him to see all he wants to, and also snap off some pictures. But, Rob, if there are Canadian troops guarding the bridge across there why wouldn’t they give him a volley to let him know he hadn’t any business on that side of the International Line?”

“I expect that’s what they will do any minute now,” Rob assured him. “We may not hear the sound of the guns over here; miles lie between; but we ought to be able to tell by the actions of the aviator. If the lead commences to sing about his ears, he’s likely to mount again; he’ll be afraid of having his gasolene tank pierced by one of them, or be struck himself.”

“When we were on the other side, Rob,” interjected Tubby, “you know we always said petrol instead of gasolene; but they both mean the same thing. There, look, will you; he’s started up again, as sure as anything, making spirals, as they generally do when ascending in a big hurry.”

As Tubby declared, the man in the aeroplane had suddenly changed his location and was now ascending as fast as he could. Something had undoubtedly caused him to do this. Rob said he wished he had thought to fetch a pair of binoculars along with him, for then they might see spurts of smoke on the ground, and possibly even discover the bridge itself.

“But then who would ever dream we’d want glasses for such a purpose?” Tubby observed. “Goodness knows we’re lugging enough load as it is. He is turning around now, Rob, and heading this way again. Do you think he accomplished his purpose, and is now bent on getting out of range of those bullets?”

“Very likely,” the other replied, “though his danger was more imaginary than real. To strike a moving aeroplane at that height with an ordinary military rifle would be next door to an accident. Haven’t we seen air pilots take all sorts of daring chances, with shrapnel bursting all around them?”

The three scouts watched until the mysterious machine had vanished toward the south. They could hear the sound of the motor as it passed high overhead, though at a considerably lower level than when going the other way.

Once more then they started off, though Tubby had great difficulty in “getting a move on him,” as he called it; for that load on his back seemed to make him feel like Sinbad the Sailor when the Old Man of the Sea refused to dismount from his shoulders, after being assisted along the way, demanding that he be carried still farther.

The afternoon was now beginning to wane very fast. Already the westering sun had sunk far down in the heavens, and was heading for the horizon. While their conversation had been mostly upon the entrancing topic of that strict neutrality which had been enjoined on all citizens of the United States while the World War was in progress across the sea, at the same time Tubby’s thoughts would frequently stray to his own present troubles.

“It doesn’t look much like we would run across that old logging camp to-day, where Uncle George was going to make his first stay, does it, Rob?” he was heard to ask for possibly the sixth time.

And as he had patiently done on every other occasion the scout leader answered him pleasantly.

“I’m sorry to say there’s little chance of that happening, Tubby, much as all of us would like it. According to my rough chart, we must be getting in the neighborhood of that camp, though, and, if lucky, we might even run across your uncle to-morrow. Certainly, if we hear any shooting near by we’ll give a shout, and try to find out who’s who. That’s the best I can say, Tubby.”

“Thank you, Rob, very much,” said the fat boy sweetly. “I know well enough that if it depended on you we’d arrive in camp inside of half an hour. Then, having accomplished my mission up here, we could all give ourselves up to a delightful ten days of knocking around, and doing some hunting with his guides. That means we’ll soon have to call a halt ourselves and camp?”

Rob had to laugh at the vein of pleading he could detect in Tubby’s voice when he made that apparently innocent remark.

“I’m looking around for a good site, Tubby,” he announced, and at that the moon face of the stout member of the patrol fairly beamed with pleasure.

It was not more than ten minutes afterward when Rob stopped short.

“Here’s where we spend the night, fellows,” he told them.

“A bully good place,” assented Andy, casting a look of appreciation around at the trees, with several openings that allowed them to see the sky, and gave a promise of all the fresh air they would want.

“Yes, and I hear a brook gurgling along near by!” declared Tubby; – “the main reason why you picked out this place, Rob. The water left in my canteen is getting pretty stale, so I’ll be mighty glad to get a decent cool drink of sweet water.”

He hastily slipped out of the broad bands of his pack, and scurried over in the direction whence that pleasing drip of water was heard. The others saw him stop and then lie flat on his paunch, for with Tubby it was not so easy to get his mouth down to a low level, owing to his peculiar formation; usually his heels had to be higher than his head, just as you would tilt a barrel up to make the rim come in contact with the ground, all owing to that curve of the staves.

As they carried no tent, for that was utterly out of the question, it would be necessary for the trio of scouts to make some apology for a shelter calculated to keep the dew or the frost from chilling their bodies, as they slept in the open.

But, indeed, this was only a delight to these lads, accustomed as all of them were to roughing it. Many a time in the past had they constructed a brush shanty that, in an emergency, might even shed rain to some extent, and would surely afford them shelter from the chilly night air.

All of them got busy immediately, fetching branches and every manner of material that would be needed in the task. While Rob himself took over the job of building the shack, he had Andy cutting wood for a fire, and Tubby dragging further supplies of fuel toward the spot, so that altogether it made quite an animated picture, with everybody working like beavers.

Before the evening was fully upon them, things began to take on quite a homelike appearance. The shanty was completed, being rudely built, with a decided slant toward the back, and an open front. Some sportsmen’s tents are made on the same pattern, the idea being to have the fire so placed as to cause the sloping roof to reflect the heat that comes in through the open front.

Then came the always delightful job of cooking supper. No boy was ever known to object to lending a hand when this task is broached. Tubby, being something of a chef by this time, due to a grim determination to excel in one branch, even if he could never equal Rob in woodcraft knowledge, or other fellows in their several fads, had taken it upon himself to carry out the arrangements.

His depression had fled. The other boys were so full of optimism that it seemed to fill the air, even as that tempting smell of coffee, with fried onions, potatoes and bacon as accessories did. A more despondent chap than Tubby must have yielded to the general feeling of satisfaction.

Witness them, therefore, a little later on, spread out close to the fire, each with his legs crossed under him tailor-fashion, and bent on stowing away the heaping pannikin of hot food that had been served out as his share of the supper; while the big tin cups were brimming full of fragrant coffee that, as Andy said, “went straight to the spot every time.”

The first edge of their ferocious appetites appeased, the boys did not hurry, but took their time in eating. It was that delightful hour of the early evening in the pine woods when all Nature seems to be hushed, and the heart of the camper rejoices in his surroundings, which he joyously compares with the unhappy lot of those mortals who are compelled to remain amidst the skyscrapers of the city, chained to their desks, while the camper owns the whole world.