“Why, by chance my friend here, Ralph Kenyon, who has trapped all through this section in years gone by, saw two men talking and acting in a strange way.  They’ve been spying on us, too, while we’ve occupied the old shack close by.  They even crept in while we were off yesterday, to steal some plans of an aeroplane improvement which this other scout, Bud Morgan, had carelessly left there.”

“Two men, you say,” the officer commented, knitting his brows with sudden suspicion and uneasiness.  “Could you tell whether they seemed to look like natives or foreigners, son and he wheeled so as to face Ralph as he asked this.

“I had an idea that one looked like a Japanese and the other a German,” the boy answered promptly.

At this, the army man rubbed his chin and seemed to consider.

“I’ve taken you into my confidence so far already, boys,” he observed presently, “that I suppose I might as well go right along and tell you everything.  We are up here, representing the Flying Squadron of the army, to experiment with a new war aeroplane much more powerful than anything before devised; also to ascertain whether there is any truth in the wild claims put forth by the inventor of the latest explosive, that his discovery must make war so horrible that nations would be compelled to keep the peace after this.  And, judging from what that one small bomb did here, I fancy he was not mistaken in his estimate.  We could destroy the largest battleship afloat as easy as to snap our fingers.  Of course there are secret agents of numerous Great Powers constantly floating around in Washington, trying to learn what Uncle Sam has up his sleeve in the way of new inventions calculated to destroy the enemy in time of war.  And we have feared all along that one or more of these spies may have gotten on our track.  I’m very much gratified with what you have told me, for now we know what to expect, and can avoid taking any unnecessary risk.”

“Would these foreign spies dare attempt to ruin your war aeroplane, or try to blow you all up with some of your own explosive?” asked Ralph.

“I wouldn’t put it past them,” replied the other.  “They are playing a desperate game, you understand, and have their orders from the home Governments to keep us from forging ahead too fast.  But I haven’t introduced myself as yet.  I am Lieutenant Fosdick, and I have had some little experience in army aviation.”

“I wonder if you can be the same Lieutenant Fosdick I’ve heard so much about from our Scout Master, a retired army officer named Lieutenant Denmead?” Hugh ventured to say eagerly.

“Well, this is a pleasure to be sure!” remarked the other smilingly.  “To be sure I know Denmead.  I saw a great deal of him several years ago.  And so he is spending his spare time in teaching the young idea how to shoot, but with the arms of peace rather than those of bloody war?  He was always crazy over boys, and must be a cracking good Scout Master, because he knows so much of Western life among the Indians.  He was with Miles in the Sioux War long ago, as you may know.  But what was this you said about one of your mates inventing something in connection with the management of aeroplanes?  That would seem to be right in my line, and if he has no serious objections, I’d like to hear about it.”