said the optimistic Andy; "we always manage somehow, to come out of every affair right-side up, and they get the rough end of the deal, as they should because they won't leave us alone to manage our own business. I can see some warm times coming soon, when they get to cruising around once more."

"Well," said Frank, thoughtfully, "I never believed that Percy had really reformed when he said he was through playing mean tricks. He's always kept quiet about that trip down to South America. Why, he even accused me of giving him away just because I told of our adventures there, even glossing over the part he played in our little rumpus with the revolutionists in Columbia, at the time I found my dear father, and rescued him."

"That's just like Percy," declared Larry. "Don't I size him up, though? He never knew what gratitude meant. I've been told that you and Andy really saved his life down in that upset country."

"Oh! perhaps it wasn't quite all of that, Larry," protested Frank.

"All right," spoke up Andy immediately; "at least we got those fellows out of a mighty tough hole. But it was just like Percy to declare that he was going to use some chloroform he had with him, to put the whole bunch of revolutionists to sleep, take their guns away, bind them hand and foot, and send some of the government troops out to capture 'em. So you see, we spoiled all that fine game by insisting on rescuing him and Sandy."

Larry laughed uproariously.

"Too bad about that chap," he remarked, when he could catch his breath again. "He's that slippery you never know when you've got your finger on him. And the excuses he gets up to cover his knockouts, they just sizzle. I reckon Percy is bound to be a promoter when he grows up."

"Say, let's all go down to the railroad yards, and watch Percy get his machine on the cart?" suggested Elephant, wickedly.

"Count me out, fellows," remarked Frank, immediately, "I don't want him to think I'm curious about what he bought that time he went to New York. Perhaps it's a better aeroplane than we've got here; but I don't believe it yet, after what she did for us in the tryout this day."

"Besides," observed Larry, "the chances are ten to one such a sly fellow as our Percy ain't going to knock the crates around the many parts of his machine into flinders right there in the open. He likes a little bit of mystery too, even if he hasn't got any reason to hide things."

"That settles my neat little scheme," sighed the runt, disconsolately. "Don't understand why it is that everything I happen to propose, Larry or somebody else always sits down on it, kerchunk! It's discouraging to genius, I say, and might keep a budding inventor from ever attaining his manifest destiny."

"Hear! hear!" chuckled Andy.

As for the tall boy, he came near having a fit, so doubled up with laughter did this important remark on the part of his small chum leave him.

"No danger of you ever being discouraged, or left at the stake, Elephant," he managed to say, presently. "You come up smiling after every backset. You've sure got grit, and to spare, if they did forget you when handing out bone and muscle."

"And I bet you if I'd only had the chance, fellows, I'd have dropped into the bally old lake, just like Andy did, and saved that sweet cherub, Tommy Cragan!" declared the "Bug," as Larry often called his diminutive chum, when he tired of using his other misplaced nickname.

"Sure you would," said Andy. "I was only lucky in having the chance, that's all. Why, I don't see anything in that to make a fuss over. It was just like a picnic to me. Frank wanted to go the worst kind, but he couldn't let go the levers of our new and dandy machine, which might sail away up in the clouds."

"Oh! how I envy both of you fellows!" sighed Elephant, placing a hand on his breast, though Larry told him that his heart was probably located on his right side, which would account for the flutter he fell into whenever he thought he detected an opportunity for distinguishing himself approaching.

But everybody took these sharp sayings of Larry Geohegan in the same happy-go-lucky spirit in which they were uttered. No one had more friends and fewer enemies than the tall boy; because he was generous to a fault, humorous in his remarks, and the life of the camp when out with any of his companions.

Andy had stalked back into the shop again, though Frank had looked after him as though inclined to wonder what ailed his cousin to be so mysterious in his actions.

"Forgot to take his change out of the pockets of those wet clothes?" suggested Larry, noticing the upraised eyebrows of Frank.

"I don't know about that," returned the other, stepping back a pace to where he could glance through the open door. "He's gone straight to the drawer where we keep some of our stuff. There, he's taken out the marine glasses that I just put away. What under the sun do you suppose Andy wants with them? He doesn't look up at the summit of Old Thunder Top, where we landed from our monoplane last summer, being the first human being ever to step there above the big cliffs. No, Andy has gone to a window with the glass. He seems to want to keep out of sight. Now, I wonder why?"

"Three to one he just saw your sister Janet going along the further road; and couldn't keep from wanting to admire her at close range," chuckled Larry.

"But now he's elevating the glasses," Frank went on. "He seems to be interested in that old mill you can see yonder above the trees. I declare, I did see something moving then in one of the upper windows. That beats everything. To think of Andy having such sharp eyes."

"Oh! the boys used to play there last summer," ventured Elephant; "though since then nobody goes near the old place. I was told it had become the haunt of hoboes this summer. Anyway, the boys fight shy of it right along now."

"Here comes Andy; now we'll know," said Nat, just as smartly as any of them could have spoken, for his hurry spell was over, and he had command of his vocal chords once more.

"Wondering what took you inside to get the glasses," remarked Frank, as the other joined them, a frown marked on his usually placid face. "And then, what made you go to a window instead of standing outside openly, and looking?"

"I'll tell you," returned Andy, solemnly. "I didn't want 'em to see me peeking."

"You mean the fellows in the old deserted mill?" asked Larry.

"No other," came the quick reply, "I don't know how it came to strike me, because you know as a rule I ain't suspicious; but something about the way those two men in the touring car looked so greedily at our new aeroplane gave me an idea it might be them."

"Goodness gracious!" gasped Elephant, his eyes round with wonder and excitement.

"And was it?" demanded Frank, hastily, frowning at the same time.

"Nobody else," replied Andy, impressively. "They must have swung around, passed up to the old mill on that side road, and from the upper windows have been watching us all the time through the fieldglasses they carry!"

CHAPTER V

FIGURING IT ALL OUT

"It begins to look as though you were right, Andy, and that these strangers certainly feel an uncommon interest in what we've been doing up here," said Frank, seriously.

"Oh! I don't take much of the credit for hitting on that idea, Frank," declared the other Bird boy, quickly. "You kept watching that Marsh right from the start. I could see a question in your