Lieutenant Fosdick loaned them a pair of glasses through which they could keep track of the distant aeroplane.  They saw it perform several queer “stunts,” as Bud called it, that caused them considerable astonishment.

“Why, say, it turned completely over that time, just as neat as you please!” Bud exclaimed, so interested that the others could not get the glasses away from him again.  “There she goes a second time, as slick as anything!  I’ve done the like from a springboard when in swimming, but I never would have believed anybody’d have the nerve to loop the loop three thousand feet up in the air.  Oh! what if it didn’t come right-side up again!  What a drop that would be!”

“Taking chances every time, and that is what our lives are made up of mostly in the Flying Corps,” the officer said grimly, with a shrug.  “Any day may see our end; but like the men who drop from balloons with a parachute, we get so accustomed to peril that it never bothers us.  Constant rubbing up against it makes a man callous, just as working with the hands hardens the palms.”

“They seem to be heading back now,” observed Ralph.

“Yes, my colleague has accomplished the object of his little flight, which was partly to practice that turn and partly to look for any signs of spies in the forest below.  We’re always thinking of interlopers, you see, though up to the time you gave me that information concerning the two men, I hadn’t seen a trace of any watchers around.  They must have kept pretty well under cover all the time.”

“And might have continued to do so, only that our coming bothered them,” Ralph commented.  “They didn’t know what to make of us.  We seemed to be only boys, and yet we dressed like Uncle Sam’s soldiers; and then there was Bud trying out his aeroplane model.  That must have stirred them up some.  Perhaps they thought, after all, that we might be the ones from whom they could steal an idea well worth while.”

“I wouldn’t be surprised in the least,” said Lieutenant Fosdick.  “And at any rate we’re under heavy obligations to you boys for bringing this important information about the spies.  I’ll try to make your stay here interesting to you, in return.”

CHAPTER X

UP IN A WAR MONOPLANE

“We’re certainly in great luck!” Hugh said to the other two scouts, as they stood and watched the “bug in the sky” growing larger and larger, the monoplane being now headed for the camp.

“It nearly always happens that way, you remember,” said Bud, who had been through frequent campaigns with his leader and could look back to many experiences that come the way of but few Boy Scouts.

Bud was probably much more excited than either of the others.  This was natural, since he had the “flying bee” largely developed and was wild over everything that had to do with aviation.

To him, this accidental meeting with the bold members of Uncle Sam’s Flying Squadron was the happiest event of his whole life.  If he had been granted one wish, it would have covered just this same ground.