"Why, yes," gasped Larry, while Elephant nodded his head as if to say he agreed to all that was said, "after Percy came bustling around, asking for the Chief, and telling how somebody had busted into his place, and run off with his biplane in the night, they got to talking it over, and wondering if it could have been the robbers, and if one of 'em knew how to handle such things. So they called up the city, and asked questions. In that way they learned that there was a yegg who had been suspected of having been connected with several other jobs, though they never could just put the kibosh on him, and his name is Casper Blue, and one time he used to be an actor, and then became a pretty well-known flier, but in an accident he broke his arm, and had to give up his business. He was always a crooked sort of feller, and after that just boozed around, joined in with hobo gangs, and they believe touched up a few jobs himself. There, that's all we know; and now, what you been doing?"

"Too long a story to tell just now," declared Frank. "The colonel knows, and perhaps he'll amuse you after we've gone."

"Oh! say, are you meanin' to take after them fellers that busted the bank safe, and then got away with Percy's biplane?" asked Elephant eagerly; "don't I wish though I could just hang on behind, and be in the swim for once. You two seem to have about all the fun there is going, hang the luck, say I?"

"Well, you'd better not try it, that's what!" said Andy, shaking his head threateningly at the bare suggestion of having Elephant aboard when they made a start.

"I think we've got everything now, Andy," remarked Frank, anxious to be off.

"Hope you're taking guns along, because if you do run across them hobo fellers you'll be apt to need them right bad," Larry went on to say, also looking downcast at having to miss all the sport simply because Nature had never intended him for an aviator, as he was inclined to get dizzy when looking down from any height.

"Oh! Frank's provided for that, and besides, we don't really expect to round the thieves up, just find out if they've dropped down anywhere inside of thirty miles to the north of Bloomsbury. Shall I get aboard, Frank?"

"Yes; and after we're off, Larry, will you and Elephant do me the favor to step around to my house, and tell my folks that the Bird boys have hired out as scouts to Chief Waller? Tell dad that we'll be mighty careful, and for mother not to worry about us. You know I always call Aunt Laura mother, because she's been that ever since my own died years ago. Will you do that, boys?" and Frank sitting there ready to start, turned a smiling face upon his two friends. Even as they promised, the aeroplane started off, and a minute later soared up in the air, like a bird rejoicing at its freedom for leaving the earth behind.



CHAPTER VIII

JUST BELOW THE CLOUDS

"Good luck to you, boys!" came floating up from the ground, above the buzzing of the busy little Kinkaid motor; and looking down, they could see Larry, Elephant, yes, and the old veteran also, carrying on excitedly, as they swung their hats around.

"Who're you waving your handkerchief to, Frank; does your best girl keep her eyes on the skies all the day long, looking to see you come around?" demanded Andy, humorously.

"Yes, that's my best girl, as sure as you live; and she's standing there on the porch of our house right now, waving to me—Aunt Laura, who thinks just as much of me as any mother could. But Andy, neither of us said anything when Larry told about that hobo aviator named Casper Blue; yet he answered the description the bank watchman gave of the smaller man who had a stiff arm."

"Oh, I noticed that, all right, even if I didn't look your way," returned Andy, promptly. "It sort of clinched the nail we drove through didn't it, Frank?"

"Seems like it," the other went on to remark. "And the chances are ten to one, we've got the story down fine right now, know who one of the robbers was, why they wanted to steal an aeroplane to make their get-away in, and all that. But there are a few things we don't know, that'd throw a little more light on the affair."

"As what?" queried his cousin.

"Well, for one thing, the Chief seemed to think the thieves might have had inside information, they seemed to know so much about things connected with the bank, our having an aeroplane, where we lived, what our habits were, and then about Percy's biplane in the bargain. Now, that's something serious; if there's a man in Bloomsbury who's in league with such rascals he'll be apt to help them out again later on if they get away with this job; and he ought to be found out."

"Whew! looks like we've got a big job on our hands if we hope to do all that sort of thing," commented Andy, with a whistle to indicate his feelings.

"Nobody said we even think of trying," laughed Frank, as he stopped mounting upward in spirals, and headed away toward the north.

It was a glorious view that they had now spread out beneath and around them. Neither of the Bird boys ever tired of such wonderful sights; and although by now it had become an old story, they enjoyed it as much as ever, even if their former sensation of awe had given way to one of familiarity.

They could see the entire outlines of beautiful Lake Sunrise, with its many coves, and points jutting out, the water glistening in the sunlight, as the morning breeze fanned it gently.

Why, yes, there was the little lake steamboat called the Mermaid, passing along the northern border of the lake, on the way between the town of Cranford, on the shore opposite Bloomsbury, and headed toward a small lumbering camp far up the left bank, possibly to deliver supplies, after which she would point her nose down toward the home town, which was of more importance than any other station on Lake Sunrise.

The boys did look back, dear though the scenes around home must ever be for them. It was characteristic of these lads that once they put their shoulder to the wheel, or in other words, their hand to the plow, they would not allow themselves to be discouraged by thoughts of the home ties. That accounted for much of the success that had been their portion in the past. They could for the time being forget that there was any such place as home; and in this way they avoided the weakness that such thoughts are apt to bring along in their train.

Forward their way lay, toward those forbidding wilds far to the north, where few towns could be found, and pretty much all the country was a vast wilderness, filled with picturesque forests, wild swamps, and rugged hills.

It was just the country where desperate law breakers would choose as a hiding-place, after they had committed some crime, and expected a warm pursuit. Ordinary methods would never find them, save through a mere chance; but when one can copy the eagle, and mount to dizzy heights, with a pair of powerful glasses he can see almost everything that is going on for miles and miles around, provided he has a skilled companion along to manage the aeroplane or balloon.

And that is destined to be the greatest value of these winged messengers in future years, since it has been proven that they are not so very dangerous after all in the line of dropping explosives upon battleships or fortified places.

"Somewhere up yonder, Frank, they are probably hiding, and feeling perfectly safe from pursuit," ventured Andy, who was sweeping the marine glasses around and examining the country ahead with more than common interest.

"Look how Old Thunder-top stands out today!" remarked Frank, turning for just an instant to glance upward toward the left, where the high mountain towered, its heavily wooded sides looking as gloomy as ever, and the white cliffs that made the summit inaccessible to human feet, appearing almost dazzling in the glittering light of the undimmed morning sun.

"And say, there's our old friends, the eagles that had a nest up there, and gave me such a warm time when we first reached the top." Andy cried, as he focused his glasses on a sweeping pair of huge birds that were heading their way, as if meaning to investigate, and find out what manner of rival this could be, invading their native element.

"They know too much to bother with an aeroplane by now!" declared Frank, laughing again. "Why I'm thinking those birds have hardly grown new feathers in place of the lot they lost that time they fought us so savagely."

The memory appeared to amuse his cousin also, for he could be heard laughing heartily, even above the purr of the now steadily going motor that sent the propellers whizzing around so rapidly; for there was one fore and aft, as is the case with all biplanes, the engine being behind the pilot and his companion.

"Tell me if you can remember, was that other aeroplane headed straight up the lake the last you saw it in the early morning light?" Frank asked.

"That's right, Frank; but then I couldn't say just how long they kept along that same course. When those hundreds of old crows came sailing along on the wind, cawing to beat the band, and going every-which-way, I lost sight of the biplane. After that it would have to be just guess work."

"But we've got a good pointer to start with," insisted Frank. "They wouldn't be so apt to head toward the south, east or west, because in those directions there are plenty of towns and villages, and these could report seeing a strange biplane passing over, so giving the police a clue. No, chances are ten to one they kept right on toward the north. And there's where we've got to do all our searching today. We can just comb the whole district over, and anything that looks like the stolen aeroplane is sure to catch our attention from this height, don't you think so, Andy?"

"I reckon it will, Frank; but the only thing bothers me is that things may have worked all right with the rascals, and by now they're away off, so far distant that we'll never in the wide world get in touch with them, the more the pity."

"Well, it's never been a habit of ours to own up beaten till we've done everything under the sun to win out. And Andy, we've only started as yet. The field is before us, you know, with a whole day's supply of gas to push us on, if we want to keep going. So I'm not asking any favors, and expect to do just my level best to find out where the bank robbers have gone."

"And if we hunt around a whole lot without getting tabs on the pair, why, we can drop down somewhere in a town, and get in touch with Bloomsbury Headquarters. The Chief as much as promised that he'd leave word there to put us wise to anything that had been learned by way of the telephone, from other places. And given a clue in that way, we might take a fresh spurt, you know."

"Just so, Andy," agreed the other, bending his head to watch how some part of the machinery was doing its duty; for that is always the weak link in modern aviation, nearly everything depending on the engine fulfilling its part perfectly.

Andy continued to make use of the pair of glasses that magnified objects in the far distance so wonderfully that a man could have been recognized easily a mile away, and perhaps much further, if the air were real clear.

Now and then he turned them to the right. The beautiful lake always attracted him very much like a magnet would, whenever he had a chance to look out over its glistening bosom.

And there was the little steamer, just as Frank had said; why, he could even distinguish Todd Pemberton up in the pilothouse, grasping his wheel and guiding his charge among the shoals that were charted in the northern end of the lake as dangerous, that is, for green hands at the tiller or wheel of a boat propelled by sails, steam or gasolene.

They were moving in a line that would carry them up along the shore, and consequently every minute they drew nearer the small lake steamer that was heading toward them.

Passengers could be seen on its deck, and possibly every eye was glued just at that particular moment on the aeroplane that was buzzing go steadily northward; perhaps it might have been the first time some of these people had ever seen such an interesting object; but in the region around Bloomsbury it was by now a common sight, with such enterprising young air pilots as the Bird boys and Percy Carberry in the field almost every decent day.

All at once Frank was heard to utter an exclamation.

"Turn your glasses straight ahead, and see what that can be fluttering among the bushes at Norton's Point, Andy!" he called out hastily.

When the other had swung around, and covered the region spoken of, he quickly gave the desired information.

"Somebody seems to be shaking a handkerchief or something else white," he observed. "And it don't look like just waving at the steamer either, for they do it after a system, as we would signal with wigwag flags. There, I counted seven times he did it; then comes a halt, and one, two, three times, another halt; and once more he starts in, this time three, four, five, and then stops. Now, what do you suppose the fellow means by that, and who can he be waving to, Frank?"

"You'd expect it might be some one out on the lake; can you see any small boat in sight, Andy; or any one waving back from another point?"

"Not a thing, as far as I can see," replied the boy with the marine glasses.

"Suppose you try the steamer, then," suggested Frank, meaningly.

Immediately Andy gave an exclamation of astonishment.

"I see a signal moving, Frank, and it seems to be copying the one on shore," he hastened to remark, excitedly.

"Where does it come from, the passengers that I saw pushing up against the rail, and staring at us; are any of them interested, do you think?" continued Frank, who just then could not turn his head to look, but must depend on his chum.

"Well, no," answered Andy, "it seems to come from the pilothouse, and must be Todd Pemberton, himself."



CHAPTER IX

THE PILOT OF THE MERMAID

"So, it's Todd Pemberton, is it?" remarked Frank, "I think it'll pay us to slow down a little, and look into this white rag-waving business."

"Goodness gracious! you can't be thinking that Todd is in touch with the bank robbers, can you, Frank?" Andy exclaimed, astounded, apparently, at the very thought of such a thing.

"Oh! I'm not up to that point of saying anything—yet. But all the same it's what I call interesting, you know," the other replied; and from this Andy could easily guess that while Frank might have notions about the matter, he did not care to commit himself so early in the game.

"Yes, that's so," Andy replied, still having his eyes glued to the binoculars.

"What's doing now?" continued Frank.

"Nothing that I c'n see," replied the other.

"No more white handkerchiefs waving around the point, eh, Andy?"

"Not a blessed thing; and Todd's quit too. Guess they've come to some sort of an understanding. Wish I knew what seven, three, five meant; something pretty interesting, I'll be bound." Andy went on to mutter, half to himself.

"Well, we can only guess, and that's the extent of it," Frank was saying, in a rather serious tone, as though he believed there might be more in connection with the little affair than a mere exchange of civilities.

"How about Todd Pemberton, Frank?" asked the boy with the glasses.

"Well, you know him as well as I do, perhaps better," returned his cousin.

"I mean, wasn't there once something against him? I know, Frank, that my guardian signed a paper about getting Todd his position with the steamboat company this last spring; they always get him to sign everything going, he's so good-natured and what you call an Easy Mark."

"Yes, they came to my father too, and he put his name down, I remember. As near as I can say, it was a petition to ask the company to give Todd the position of pilot; and stated the belief of all those who signed that he would make good. He used to be a pilot on Lake Sunrise, and before that on one of the Great Lakes."

"But, Frank, why the petition, if he was able to fill the place you'd think all he had to do was to make application, and then jump in?"

"Well, it seemed to be pretty generally known about Bloomsbury that Todd had not always been as straight as he is today; and lots of people believed he would never hold his place a week; but he's had it all summer now, and seems to be giving satisfaction, all right," Frank went on to say.

"But there was a past, you mean; Todd had gone the pace, and used to drink and gamble, I suppose. Perhaps, now, he even used to herd with a tough set. How about that, Frank?"

"It's so all right. Todd got down pretty low, and was even a hobo, I heard, before he took a brace, and came back to Bloomsbury to make a man of himself again."

"Gee! I'm real sorry to hear that," Andy muttered.

"What? That he reformed?" demanded the cousin, in pretended surprise.

"Shucks! no; but about his having been a tramp; because, don't you see, Frank, it makes things look black for Todd. Remember, don't you, about what the Chief said when he spoke of the yeggs knowing so much about things, that he thought they must have had inside information; and that somebody familiar with Bloomsbury ways helped them figure it all out. Looks bad for Todd, that's what, Frank."

To hear Andy talk you would think that the party in question must have been a personal friend, at least, when, in truth, he only knew Todd Pemberton to speak to, as he did a thousand other people in and around the home town.

"By that you mean you're afraid he's fallen in with some old companions in crime and been tempted, or forced to join them in this raid on the bank?" was the way Frank put the matter direct.

"You've covered what I do believe, as sure as my name's Andy Bird."

"Well, let me say that I think the same way you do," Frank went on to remark.

"Good!" cried Andy, in a delighted tone. "Sometimes we agree, and again we have different minds; but in this case it looks like we might be on the same raft."

"Take another good squint at the point, Andy, and see if you can pick up that man again, the fellow who was doing all that tall Wigwagging."

"I'm looking, Frank."

"What d'ye see there now?" the other continued.

"Nothing—that is, there are stones, and moss, and trees, and perhaps birds flying around this way and that; but never the first sign of a human being can I discover anywhere, Frank."

"Still, we know there's one man there at least, perhaps a pair of them hiding somewhere around that desolate place. Why, Norton's Point is, I guess, about the meanest and loneliest place of all the Disston Swamp lumber company. Nobody hardly ever goes there except to shoot snipe and woodcock in the fall, and yet we happen to know there's one person hiding out there, and that he knows Todd Pemberton, for they've been exchanging signals through the wigwag code."

"Looks suspicious, Frank, don't you think?"

"Looks like it might pay to investigate a little closer, Andy."

They were by this time passing over the identical strip of country where Andy had watched the signal waving. By looking almost directly down, he could see between the tall trees as only an aviator ever has a chance of doing.

"You know what I'm hoping to discover, Frank?" he remarked as he continued to scan every part that was at all exposed by openings among the trees.

"Percy's lost biplane, I take it," came the prompt reply.

"Yes, because they couldn't very well have landed without a certain amount of open space. We know how hard it is to drop into a hole, and worse still to climb up out of one. Didn't we have the toughest of times down there in that South American forest finding open spots where we could land with some chance of ever getting out again, without cutting trees down that were as big around as a young house?"

"But I don't hear you shouting out that you've made any sort of discovery, up to now, Andy?"

"Well, no, for a fact I haven't. But Frank, I wish you could take the glass and let me hold the wheel for a minute."

"You can tell me just as well, I think," replied the other.

"It's about the sandy beach in front of the point," remarked Andy.

"What ails it then?" Frank inquired, seeing his cousin hesitate.

"Why," Andy went on to say, "you know how powerful this glass is, and how it shows up the smallest of things when the sun is just right? It's doing that now. I can look down on the sand spit at the point; and for a lonely spot where hardly a man ever comes from November to June, it looks pretty well trampled up to me."

"Trampled by men or animals?" the pilot inquired.

"I think by two-legged animals," answered the one who held the powerful lenses to his young eyes. "And it struck me that perhaps the biplane came down right there early this morning. It was headed this way when I saw it, and not so very high up; though that flock of crazy crows knocked me out of watching it for some times."

"Do you mean it fell there; that they had an accident of some kind, Andy?"

"Might be that; and then, again, perhaps they dropped down on purpose; p'raps they mean to have another warm session around Bloomsbury before skipping out of this section for good. With the aeroplane to make a quick get-away, they might think of some rich haul they want to gather in. Am I away off in my guess, Frank, or do you kind of lean the same way?"

"I think you are getting pretty close to the truth, Andy, and that's a fact," replied the other. "But it would clinch it if you could only glimpse the biplane hidden away somewhere down there under the brush or the trees."

"That's what I've been hoping for," returned Andy, a little fretfully, "but so far without meeting any success that you could notice. But what ought we to do about it, Frank?"

"Go on, and take a wide sweep around," came the steady reply. "Perhaps we might run across another leading clue, and then this one would look foolish. We'd be sorry then, that we thought so bad of Todd. Perhaps, after all, he was only making signals to one of the men connected with the logging camp, up on the Point for something or other."

He allowed the motor to work at the reduced speed that it had been carrying on ever since quitting the home field, where the workshop and the hangar stood. Andy still continued to use the glasses, as though he had not quite given up all hope of making some sort of discovery.

Once, however, they had left the northern end of the lovely lake behind them for good, and only the forest lay below, Frank quickened matters somewhat. Truth to tell, he hardly knew what to think, and whether what they had witnessed could really have any bearing on the solution of the puzzle or not.

Certainly if the hunt was only kept up in automobiles, that required fairly decent roads to allow of their getting along, there was not much chance of the authorities ever discovering the concealed hobo thieves; for they could not get within a mile of the shore up there at Norton's Point by such methods. The only way it could be reached was by boat; or possibly through the means of an aeroplane, such as the Bird boys were now using. Few places but could be spied upon, when one had the means for passing over the most inaccessible thickets and rocky hills.

After a time they had gone many miles. Occasionally a small hamlet was seen below; and then would come once more the woods that extended over such a large space of territory in this part of the country. This was generally because of the swampy nature of the ground, which prevented farming operations being carried on, while the difficulty of getting the logs out of the bogs had deterred lumbering thus far.

Andy had done his part of the work faithfully. He had scoured the territory over which they passed, and never did a break occur, however small, but he clapped his eyes upon it, and examined the open space thoroughly.

"There's Rockford ahead, and we've passed over the whole stretch of swamp and forest. Suppose, now, we dropped down on the commons, and get Bloomsbury on the long distance phone; perhaps they might have some news they could give us," and as Andy at once agreed to the proposal, for he was thirsty anyhow, and wanted a drink of soda water the worst kind, Frank began to descend gracefully.

They had about half the population of the place gaping at them as they finally landed on the big green. Frank asked his cousin to stay by the machine while he sought police headquarters, and asked to get in touch with the home town.

He had no sooner made the connection, and heard some one answer him after he told who he was, when there was sent along the wire some information that rather gave Frank a shock, because of its nature, and the fact that it seemed to fully dispose of the theory he and his cousin had already formed.



CHAPTER X

HEARD OVER THE WIRE

Luckily the center of interest remained around the odd looking aeroplane with the metal pontoons underneath its body, so that Frank was allowed to walk away almost unnoticed, when he had secured the important information he inquired for, and which was leading him to the drug store nearest the town green.

True, an aviator had landed in Rockford on one or two occasions, for some reason or other, in times past. Since the Bird boys could not remember having done so, possibly it may have been Percy Carberry, anxious to enjoy the stares of the good people, and pose as a great fellow.

But this was a type of air machine with which none of them were familiar; and as so much space was being taken up even in the local papers with the accounts of the wonderful doings of daring navigators of the upper currents, it was only natural that some bright boy should speedily guess what manner of craft the chance visitor to Rockford must be.

"Hey! that's a hyderplane, mister, ain't it?" demanded one sharp-eyed chap, after he had glimpsed the construction of the aluminum pontoons that were just kept from contact with the ground by the bicycle wheels.

"Have you ever seen one before?" asked Andy, desirous of keeping up friendly relations with the crowd, for he knew how important that might prove, since, as yet, no man wearing a blue uniform had put in an appearance; and should any hoodlum choose to play "rough house," or try to be too familiar with the apparatus, there was always a chance that some damage might be done.

"No, I ain't, but I seen a picture of that 'ere Coffyn feller, a-flyin' down on the Hudson river nigh New York; and she looked a heap like this here shebang," came the quick response.

"Well, you guessed right that time, for that is what it is called, a hydroplane; because it can be navigated on the water as well as in the air. And if you'll please stand back, so as not to bother with anything, because the least handling may put the whole machine out of tune, I'll be glad to tell you something about how we manage to use it as a boat."

Andy knew how to manage, and he exerted himself to entertain the crowd while Frank was absent, keeping their interest aroused by little stories of things that had happened to birdmen in recent times, and which were of course well known to him, from the fact that both the cousins kept in close touch with all that went on in the world of aviation.

All the while Andy was keeping one anxious eye out for the sign of a blue uniform and brass buttons, while new additions kept arriving constantly to swell the eager crowd gathered on the park green.

In the end he was vastly relieved to discover a policeman hurrying up, looking as serious as though he expected to discover a fight, or two youngsters matching pet roosters, to the delight of the gathered host; for since the flying machine lay on the ground it was mostly concealed from his view; and he would never have known what it was anyway.

Of course, when he arrived on the scene and took command Andy quickly gained his favor by a little subtle flattery; and after that felt that he was, as he himself expressed it, "on Easy Street."

Meanwhile Frank had proceeded direct to the drugstore on the corner, about two blocks away from the end of the green, where they had told him he could talk over the long distance phone with Bloomsbury.

He was pleased to find that they had a regular booth in the store; for he knew of numerous cases where the phone simply stood on a little stand, and everybody could hear what the subject of the talk might be, especially one side of it.

Once closeted in the booth he hastened to ask for connection with Police Headquarters at Bloomsbury. There was some little delay, as though these long distance calls might be of rare occurrence in the local Central; but finally he received notice that connection had been made, and he was at liberty to start his message.

"Hello! this Bloomsbury?" Frank asked first of all in a cautious way.

"Yes," came the reply, distinctly enough.

"And is this Police Headquarters?"

"Yes."

"This is Frank Bird speaking and we are over in Rockford; get that?" Frank continued.

"Yes," again came the reply from the party at the other end.

"Chief Waller asked us before we left Bloomsbury to keep in touch with Headquarters, and that you would supply us with any new information that might come to hand while we scoured the country overhead, looking for signs of the men who robbed the Bloomsbury bank last night, and escaped in Percy Carberry's biplane. Who is this I am talking to, please?"

"Officer Green, Frank."

"Oh! is that you, Joe; I didn't recognize your voice over the wire," Frank went on to say. "You heard what the Chief said about giving us the latest news, didn't you, Joe?"

"I certain did, Frank," answered the man at the other end of the wire.

"We've covered quite a large territory up to now, and think we've run across a clue; but we want to make sure before putting the bloodhounds of the law on the scent. Get that?"

Frank was wise to the fact that Officer Green took himself and his position on the local police force very seriously. True, he had never done anything very great, to distinguish himself, beyond once stopping a runaway horse that some people said was too decrepit to have gone twenty paces further; and rescuing a little pet dog that had fallen into the lake from a wharf; but then he believed in himself; and read up all the thrilling stories of police achievements that were published in the New York papers, satisfied that sooner or later the day was bound to come when he would be able to prove himself a grand hero.

And that was just why artful Frank used that phrase "bloodhounds of the law," for he knew that it would cause Joe Green to puff up with pride, and feel more kindly disposed than ever toward the speaker.

He gauged matters exactly right, too, it seemed; for when the police officer spoke again it was with additional eagerness.

"Good for you, Frank; all Bloomsbury expects the Bird boys to do the old town proud again. Many the time have you done it in the past, we all know. And when you feel dead sure that you've got track of the desprit villains who looted our town bank, all you have to do is to give the police the signal, and they'll throw a drag-net around the hang-out of the yeggs. That's what we're here for; that's what we draw our salaries for; to protect the citizens of Bloomsbury against danger by fire, flood, robbers and the like."

Frank knew only too well how Officer Green liked to talk, especially when once started on the subject of his exalted office; and accordingly he thought it time to cut him short, before he could get launched on the sea of police duties.

"Tell me, have you learned anything new since we left?" he asked.

"Why, yes, we've just had a man in here, who had heard about the robbery, and that it was suspected the thieves had escaped by means of the biplane belonging to the Carberry boy. He thought as how we might be glad to know that he'd sighted a flying machine just after daybreak."

"Why, yes, that ought to be an important piece of news," remarked Frank, wondering whether it would corroborate that which the farm hand, Felix Boggs, had already contributed to the fund of knowledge concerning the movements of the fleeing yeggmen.

"I thought it was; and I'm only waiting right now to forward it to the Chief, as soon as he calls me on the wire from Hazenhurst, or some other place where he's apt to turn Up," came over the wire from the home town.

"Don't cut me off, yet, Central!" called out Frank, hastily, as he thought he detected an uneasy movement, which was doubtless a sigh given by the girl, who possibly had her ear to the wire, drinking in what was being said: "I'm not near done talking yet. Hello! Joe!"

"Yes, I'm here, Frank; what more do you want to ask me?" came from miles away; and in imagination he could see Officer Green crouched at the telephone stand, as he remembered it at Police Headquarters in Bloomsbury, feeling the importance of his relations with the public as a genuine guardian of the peace.

"Why, it's of considerable importance to us to know in which direction the aeroplane was going at the time this party sighted it," Frank went on to say, "and I hope he told you that."

"Which he did without my asking," replied Officer Green, quickly, "though you may be sure I would have done the same before letting him leave, because I was on to the fact that it would be a pretty good pointer."

"Oh! he thought of it himself, did he?" the young aviator shot back, "well, that was pretty bright of him, and shows that he was a fellow to take notice. And now, please tell me what he said about the direction in which the biplane was headed, at the last instant he could see it far away in the distance."

"Exactly southwest, Frank!"

This gave Frank a sudden jar, because it upset the theories he and Andy had been forming concerning the escaping bank robbers. They had believed the two men had gone almost directly north!

"Southwest, you say, Joe?" he asked, wishing to make assurance doubly sure.

"He said exactly southwest; and as he kept repeating that word a number of times there isn't a bit of chance that I'd get it mixed. You can depend on it, Frank, and if you're away up at Rockford, seems to me you'll have to make a big change of base right soon, if you want to get in touch with them raskils."

Frank's mind was in somewhat of a whirl. He wondered whether the farm hand, Felix Boggs, could have been mistaken in what he had said; though Andy, too, had seen the biplane, and noted the direction of its flight. But perhaps this farmer, or whoever he might turn out to be, had discovered the fugitive flying machine at a much later time, after the two men had changed the course of their flight.

"I suppose you might as well tell me who the party was from whom you got your news, Joe," he remarked; though without any particular object in view, since he could hardly expect to hunt the other up, and ask more questions.

And then came the answer, that gave Frank quite a thrill, as he grasped the peculiar significance of it all.

"Why, you know him all right, Frank," said Officer Green, glibly, "he's the pilot of the little lake steamer, and his name's Todd Pemberton!"



CHAPTER XI

COMPARING NOTES

"He must have hurried up to Headquarters, then, as soon as he landed, because we saw the Mermaid crossing the northern end of the lake, bound for the lumber camp, before heading for Bloomsbury. How about it, Joe?" Frank went on to ask, as soon as he had recovered from his surprise after hearing that particular name mentioned.

"Said he heard about the robbery," came over the wire in Officer Green's ponderous tones; "and the fact of the raskils skipping out with the Carberry boy's biplane, as soon as he put foot ashore; and thinking that the police might like to know what he had seen, he just ran all the way here."

"Which I take it was mighty thoughtful of Todd," declared Frank, drily; but if he spoke sarcastically the fact was not known to the man at the other end.

"I told him so, and complimented him on his zeal in assisting the course of justice," the other continued, "which was all the more remarkable, you know, Frank, because, to tell the truth, Todd himself was once a bad egg, until he reformed, and got his present job. It does him great credit, sure it does."

"He went away after letting you know that if you hoped to capture the thieves you'd have to chase southwest, and not north, didn't he, Joe?"

"Oh! yes, about ten minutes ago, I reckon. But I assured him that if we did succeed in capturing the rogues he would not be forgotten in the division of the reward that was sure to be offered by the bank for the recovery of the money and securities that were taken, not to speak of the five hundred young Carberry has said he would pay for the recovery of his biplane and the arrest of the thieves."

"That was nice of you, Joe; but only what might be expected because your heart is as big as a bushel basket," Frank went on to say, "and when you told Todd that, how did he take it?"

"Why, he just chuckled, and looked at me kind of funny, and said he never hoped to take any of the hard-earned reward money that the police were justly entitled to because of their activities," replied the other.

"It's plain to be seen that Todd is a generous fellow. But I'm obliged to you, Joe, for giving me this information, because, you see, we've now got some foundation to build on. Goodbye, Joe!"

With that Frank rang off. He knew that he might chat with the gossipy police officer in Bloomsbury for at least fifteen minutes, but what was the use, when he already knew all the other had to tell?

And the news that had come over the wire was of considerable importance, too. He smiled as he hurried out of the drugstore, not even waiting to quench his thirst at the soda fountain, though a short time before he, as well as Andy, had complained of feeling so exceedingly dry; but then, all that was now forgotten in this excitement connected with the latest development in the robbery case.

It was back to the village green, now, with Frank.

The crowd was greater than ever, and he quickly saw there would be no opportunity for any communication between himself and his cousin until they had left for the upper realms, where, surrounded only by silence, they could converse while the busy motor hummed and the aeroplane headed as they willed, either high above the hills, or skirting the tops of the forest trees.

Accordingly, Frank addressed himself to the arduous task of getting away without any mishap. He, as well as Andy, had long since learned that it is the part of wisdom to gain the good will of a curious crowd. In that manner many friends are raised up, who are only too willing to lend a helping hand.

He quickly selected half a dozen fellows who looked as though they might be of more than ordinary importance among the boys of Rock-ford. These he particularly picked out, and asked them to assist the police officer to keep the crowd back until they could get a good start, at the same time explaining that a clear passage would have to be made ahead, and that anyone getting in the way might not only be seriously injured, but wreck the machine as well.

Proud to have been thus honored, the six boys proceeded to push back the gaping crowd and when Frank gave the word, also assisted in starting the hydroplane on its way.

A salvo of loud cheers rang out when they started, and this burst into a furious chorus as the well balanced aeroplane presently left the ground to start upward into the air.

"I'm glad that's over with," said Andy, when they were safely off the ground, and the shouts of Rockford's enthusiastic population began to grow fainter in the distance.

"Same here," echoed Frank, "you never know what will happen when a crowd is pushing all around you, every fellow eager to just say he had hold of a flying machine. There's always one or two of the lot ready to hang on and risk their lives just to see how it feels to be carried up on an aeroplane. They're the kind I'm most afraid of."

"Well, did you get Police Headquarters in Bloomsbury, Frank?"

"No trouble about that; and our old friend, Officer Green, was in charge during the absence of the Chief," the other Bird boy answered.

"Anything new developed since we left?" asked Andy.

"Just one thing, and Joe thought it meant a whole lot," Frank went on to say.

"Which was what?" inquired the other.

"A man came hurrying in and told how he had seen a flying machine containing two parties just after daybreak, and making directly toward the southwest, Andy. What do you think of that now for news?"

His cousin gave a whistle.

"Whew! important, if true!" he vouchsafed, tersely.

"That sounds as if you had some trouble believing it?" chuckled Frank.

"Well, considering what I saw myself, I'd have to know the name of this party first, before I'd believe anything he said," Andy went on.

"Oh! You know him, alright; fact is, we were speaking of the same not a great while back," Frank observed, quietly.

"Don't make me start in guessing, Frank, because we've been talking of a dozen people; but tell me right out who it is," Andy pleaded.

"The pilot of the Mermaid, Andy!"

"Gee! Do you mean Todd Pemberton?" exclaimed the other.

"Just him and no one else. Why, he was that anxious to let the police know he had seen an aeroplane steering away straight into the southwest early this morning, that as soon as he warped his boat to the wharf, Todd, like a public-spirited citizen, hiked away for Headquarters as fast as he could run, hardly waiting long enough to understand about the bank being robbed, and Percy's biplane being used by the thieves as a means of making a quick get-away."

Andy turned his head and looked in his cousin's face.

"Public-spirited citizen go hang!" he said, contemptuously. "After what we saw, Frank, it's easy for us to understand just what it was made Todd want the police to do all their hunting away off in the southwest."

"Yes, what do you think was his object?" asked Frank, as he held the aeroplane just about five hundred feet above the level ground, covered by forests, as in most places around to the north of Bloomsbury, though occasionally they ran across farms that looked like oases in the dessert.

"Why, that's as plain as the nose on my face," replied Andy, "and nobody ever had any trouble about seeing that, I guess. Todd wanted to get in a little bit of assistance for his friends, the hoboes who looted the bank; and he could do them the best thing ever by turning suspicion in nearly the opposite quarter. If Chief Waller could be assured that the last seen of the biplane before it vanished in the distance it was heading into the southwest, of course he'd take all his men off in that direction; and the bank robbers, hiding perhaps around the northern end of Lake Sunrise, would be free to do whatever they wanted. Do I hit about the same guess that you do, Frank?"

"You've just echoed what I had in mind," returned his cousin, "only I've had more time to think it over, and perhaps gone a little further than you could."

"As how?" demanded the other, promptly, just as Frank knew he would.

"Why, you know, it struck us as queer that these fellows should want to hang out within twenty miles of the town where they'd just made a successful raid on the bank. It would stand to reason that they'd be only too glad to cut for it, after getting possession of Percy's fine new aeroplane, and by keeping on north, reach Lake Ontario, and perhaps fly across to Canada, where they'd be safe."

"Yes, sure; we talked that over before, Frank, and came to the conclusion that either they'd met with some sort of accident to the biplane, and had to hold over till the fellow who used to be an aviator repaired the same; or else that they had some other robbery in mind, and wanted to make a double killing of it before skipping out."

"All right. You can see, then, that if Chief Waller and about all his men got on a warm clue that led them off to the southwest for a day or so, it would leave things open for the carrying out of this second scheme!"

When Andy heard his cousin say this so gravely he seemed more startled than ever.

"Say, I believe you've gone and struck the truth just as you nearly always do, old fellow, not by luck, but by figuring it out. To get the coast clear, then, this sly Todd Pemberton means to go on bringing in important news, and keeping poor old Chief Waller worked up to top-notch speed, chasing around down there after shadows! Yes, that must be the game they've got in hand; and perhaps that's what all those waves of handkerchiefs meant between the pilot of the little Mermaid, and the fellow we couldn't see, who was hidden in the bushes on Norton's Point."

"He was undoubtedly there just to give Todd the high sign when the boat passed. Both of us spoke of the fact that we'd never known the steamboat to keep so far north when making the run from Cranford, across the lake, up to the lumber camp on our northwest side. But now we can understand why; he wanted to make sure his partners in crime were ready for him to do his little share in the game; which is to send the police on a wild goose chase and leave Bloomsbury next to unprotected tonight."

"But whatever in the wide world, Frank, do you think they mean to try next?"

"I couldn't guess in a year," was the reply of the boy who manipulated the levers of the hydroplane so dextrously. "It might be any one of a dozen or two games. The bank isn't the only institution in Bloomsbury carrying a lot of money in the safe. And then there are several rich men we happen to know, who keep a little fortune about the house, in the way of money, jewelry, or curios. For all we know, these yeggs may even have an eye on your house or mine, because they could make a pretty good haul there."

"Whew!" was all Andy said just then; but his mind was undoubtedly filled with startling ideas.



CHAPTER XII

AT THE HOSKINS FARM

"Well," Andy went on to remark, presently, "I see you are turning back again in the direction of the head of the lake. I hope, Frank, you don't mean to go all the way to Bloomsbury, and put the police in possession of the few facts we've succeeded in picking up."

"That was not my calculation at all," replied the other, "in the first place, we suspect a good deal, but up to now we haven't got very much positive evidence on which to found a case. I'd like to know a little more before I get the Chief on the wire, and put him wise."

"Then when we get near the northern end of the lake perhaps you'll think it best to make a landing somewhere, and prowl around on foot, finding out what we can," Andy, continued eagerly; for he had become much worked up by this time, and was hoping that fortune would be as kind to them as on a previous occasion, which all Bloomsbury remembered very well.

"If we can only find a decent opening where we could make a get-away again, that is the only thing that bothers me," Frank replied.

"Now, I remember noticing a field near what seemed to be a lonely farmhouse; in fact there were a number of open places there, and they seemed to have Canada thistles growing in clumps, all a-bloom, as if the farmer had given up cultivating, and let things just go to rack and ruin. I was never up there myself, but from what I've heard my father say, I rather think that must be the Hoskins place. They say he consulted some fortune teller a couple of years ago, who told him he would some day discover a gold mine on his property that would make him a millionaire; and ever since the farmer has spent about all his time digging here and there, but up to now without any success at all."

"Why, yes, I remember hearing a lot about the queer old farmer myself," Frank went on to say. "He's got a wife, and a half-grown daughter named Sallie. I met her at a country dance last winter, and she's a pretty nice sort of a girl. Now, we've been on the move a good while, Andy, and perhaps we might manage to make the Hoskins farm around the dinner hour."

"A bully good idea, too, Frank, and don't you forget it!" cried the other, with considerable show of enthusiasm. "Now, I just bolted what little breakfast I got this morning, and already I feel hungry enough to eat nearly anything. And speaking generally, these country people do set a great table; though I don't know how it will be with the Hoskins, because, if they've been neglecting their farm to chase around after rainbows, they probably won't be any too flush with supplies. But any port in a storm, and I guess we'll be able to get filled up; if only we can make a landing, and find the farm."

"As I figure it out, Hoskins' place wouldn't be over a mile or so directly above Norton's Point, Andy," the pilot of the expedition continued, thoughtfully.

"Yes," Andy said, encouragingly.

"And perhaps, now, we might happen to run on some sort of a little clue there. For instance, one of those yeggmen may have wandered around, and bought some eggs or milk from the farmer's folks; because, if they've been camping out in the woods, they've had to eat all the while, you know."

"A good idea, Frank; and we'll ask, if we're lucky enough to happen around the lonely farm about meal time."

"I'm going to make it a point to be there, and as we've got some time to kill meanwhile, let's hop over to that nice landingplace at the foot of old Thunder top, and overhaul the machine again. There are a few things I'd like to tinker with, because I'm not quite pleased with the way they work; and you know, Andy, I'm a regular crank about having a motor run like a watch."

"Well, I'm getting that way mighty fast, thanks to your hints, and the knowledge of how it pays, when you're taking your life in your hands every time you go up in one of these heavier-than-air outfits," was what the other Bird boy observed, with what was a thoughtful look, for him; because, as a rule, Andy appeared to be a merry chap, and laughing much of the time.

Within half an hour they had successfully landed at the place indicated, and which had witnessed the coming and going of the young aeronauts on numerous occasions.

Here at least they could remain and take things easy while waiting for the morning to slip along, so that eleven would roll around. Little danger of their being bothered by curious persons here; indeed, the boys had never yet known a solitary man or boy to come around the place.

They could look up while lying there on their backs, and watch the fleecy clouds sailing swiftly past the lofty crown of the rocky mountain. And how vividly there came into their minds memories of lively times which they themselves had experienced up there on the summit of old Thunder top.

They spoke of them now, as they lay stretched out on the soft turf, and watched the two white headed eagles soaring far up in the blue heavens, around and around in circles, without ever seeming to flap their great wings.

Once the young aviators had engaged in a terrible conflict with those two mighty birds, on the crown of the mountain, where they had landed with their aeroplane, and been looked upon as intruders by the eagles, possibly under the belief that they entertained hostile intentions toward the fledglings in their nest that was built amidst the crags, close to the tip of the lofty peak.

Frank and Andy often spoke of that thrilling episode, but never without some sort of little shiver, because it had been a serious time with them since one blow from those powerful wings might have toppled them over the edge of the dizzy height, and sent them to their deaths.

But they had succeeded in beating their feather antagonists off by the aid of clubs which they wielded with vigor; and after the eagles learned that no harm was intended to their young by these bold navigators of the upper air currents, they came to have more respect for the strange winged thing that came humming up from the earth on more than one occasion.

When eleven o'clock came around, the boys were off again, and headed toward the northern end of the lake.

Of course they kept close down to the treetops, because, once they discovered the opening, they would wish to drop into it as easily as possible.

Suddenly Andy, who was on the lookout, while Frank paid more attention to the easy working of the motor, and the steering of the hydroplane, uttered an exclamation of satisfaction.

"I see it, dead ahead!" he remarked, in a satisfied tone. "We made a bee line to the place from the foot of the mountain, Frank. And unless I'm away off in my guess, the farmhouse lies over yonder beyond the trees; so nobody's apt to see us come down; and we can make any sort of yarn we want, to explain just why we're here right now."

"We can do that all right, without telling anything that isn't so," replied the other aviator. "The farmer doesn't know us, though Sallie will, and on that account we must be careful what we say. But the dinner's the main thing just now. And at the same time we'll try and pick up a little information, if Farmer Hoskins happens to know anything that would interest two fellows of our stamp."

He passed over the opening once, to make sure that it contained all the necessary requisites for a successful landing, and also a launching of the airship. Then, making a graceful sweep back again, Frank allowed the aeroplane to drop lightly to the ground. It landed in almost the center of the field, and both boys saw that they might get away again without a great amount of trouble.

"Fine!" was the comment of the pilot, as he jumped to the ground, and bent over to detach some part of the machinery without which the motor, as Andy always said, "would not move worth a cent." This he often took with him, just as a chauffeur might the spark plug of an automobile, rendering it helpless unless the would-be thief were prepared to supply the deficiency off-hand, which was a remote possibility that never worried Frank.

"Now for grub!" announced the hungry Andy, leading off in the direction where he had reason to believe the farmhouse lay; Frank always declared that Andy had a most wonderful nose for a meal that was preparing, and could spot a camp a mile away just by the smell of frying onions, or coffee cooking.

At any rate he proved to be a successful pilot on the present occasion, for in a short time they were passing through an abandoned grain field where the bees and butterflies were swarming about the many lavender colored flowers of the great clumps of thistles; and the smoke from the farmhouse kitchen arose just over a little knoll.

"Told you so," said Andy, as they drew near the house, and caught fragrant odors of cooking in the air.

Upon their knocking a girl came to the open door, and recognized Frank immediately as a boy she had met at the country dance the preceding winter. But nothing she said would indicate that the Hoskins, living here away from the world as they did, with the head of the house spending all his time hunting for that treasure-trove he still believed in, had heard anything to speak of about the wonderful things the Bird boys had been doing lately.

Frank was glad of this, and he just casually mentioned that they chanced to find themselves near the farm, and wondered if they could get dinner there.

So the good housewife was brought out, and with true country hospitality she immediately invited both boys to sit down with them, although saying that they were not as well supplied with the good things that used to be seen on their table before father took to boring those horrid holes all over the place, thinking to strike a coal vein, or perhaps a silver mine.

He was off now, and would not show up until night, for the farm was one of vast dimensions, and covered miles of territory.

"But we have a boarder," said Sallie, as they sat down at the table. "Sometimes he's here to meals, and again he gets so far away chasing his butterflies that he just carries what he calls a snack in his pocket. Such a queer little man he is too, with his brown glasses on, and always running this way and that with his little net in which he captures the butterflies that come to the thistles on our old barren fields. Perhaps he'll turn up while you're here. I'd like you to meet Professor Whitesides, who is from a big college, he tells us, and spending his vacation in the way he likes. Sometimes I think he's a little off up here," and she touched her head as she said this, "and that perhaps he got hurt worse than he thinks, the time he met with the accident that crippled his arm."

Somehow Andy looked up when he heard about that broken arm to find his cousin giving him the wink, while his eyebrows were elevated in a suggestive way, just as much as to say:

"Now, here's something mighty interesting already that would pay us to look into; because we know of another fellow who is troubled with a crippled arm and his name happens to be Casper Blue!"



CHAPTER XIII

THE BUTTERFLY COLLECTOR

The dinner passed off without the odd little professor showing up, although Sallie said it was nothing unusual for him, and that he was liable to appear at any time, carrying his little white hand-net, and a small handbag in which he claimed to keep the trophies of the chase that had been run down during his last campaign.

Frank wanted to get a chance to confer with his chum, and as soon as he could conveniently withdraw from the table, giving Andy a nod, he went out on the porch where he could look down the lane that led to the poor road, which in turn, after many trials and tribulations merged into the main pike.

Andy joined him there a minute later, with a question in his eye.

"Professor Whitesides!" was what Frank remarked.

"And a butterfly collector at that!" Andy went on to say, with cutting sarcasm.

"That sounds pretty rich, to me," his cousin continued. "I wonder, now, could it be possible that the other man we've heard of lately, Casper Blue, is playing a smart trick on these honest people, who would never dream that he could be anything else than he claimed."

"It would give him a splendid chance to wander around just whenever and wherever he wanted to go, and nobody to ask questions. Then, when he got hungry, why, he could drop in at the farm. Perhaps he don't like camping out as well as the other fellow; perhaps his health is too delicate to stand roughing it. Or he might have any one of a dozen other reasons for carrying on this way; always providing that this is Casper Blue."

Andy was brimful of excitement. His manner would forcibly remind one of the nervous tension that seizes upon the hounds when the scent grows strong, and they anticipate coming in sight of their quarry at any moment.

"We're taking a good deal for granted, seems to me," remarked Frank.

"Of course, but then see how queer it is that this man who calls himself a college professor, and collector of bugs and butterflies, should just happen to drop in here at the Hoskins farm, where the thistles grow so wild, and the moths and other things are to be found by thousands. We never heard of him in town, that I can remember. And then he's small in size; together with a stiff arm, that was injured in an accident; well, wasn't Casper Blue knocked out of his job as an air pilot by his arm failing him when he had to handle the levers like a flash, or have his aeroplane turn upside-down, Frank? I tell you I just feel dead sure it's our man, and that we've found the clue we want the first thing."

"Well, if we could manage to get a peep into his room perhaps we would run across something worth while?" Frank suggested.

"We might pretend to be deeply interested in butterflies ourselves," remarked Andy, "even if we don't really know one kind from another; and perhaps, if you gave Sallie a sly hint that you'd be tickled to see what sort of a collection her professor has with him, she'd let us look in his room."

"We'll make the try, anyhow," said Frank, firmly.

"But think of this Casper Blue being able to carry out the part of a learned professor, would you? That is something most yeggmen would find a pretty hard proposition, don't you say, Frank?"

"Well, stop and think a little, Andy," was the other's reply to this. "From all accounts this man isn't just a common, everyday hobo. He used to be known as something of an aviator before he met with that accident that disabled his arm, and made it impossible for him to go up again. And the fact is, I seem to remember having seen that name mentioned among a list of airmen who had been either killed, or knocked out by accidents happening to them."

"That's all right, Frank, but it takes a pretty smart man to carry out a part like he's doing."

"Didn't Larry tell us that this same Casper Blue had once been an actor before he took to the air for a living?" asked Frank.

"You're right, he did that same thing, but somehow it seemed to have slipped my mind. But you never forget a single thing, do you, Frank? And if he used to be an actor, why, of course Casper would find it easy to play this part. Perhaps he's just enjoying it the best you ever heard of. Some people are never happy unless they're hoodwinking others."

"Let's go back and find Sallie, and get to talking about butterflies and gypsy moths, and all sorts of things in that line we can think of," suggested Frank. "Then she'll believe we're head over ears interested in what her boarder is doing, and if I give her a little hint she may ask us to step in and take a peek at his room. Of course we mightn't pick up anything worth while there; and then again there's always a little chance we could."

"It's worth while, I think," declared Andy, who seldom disagreed with any proposition his cousin advanced, simply because Frank was usually so wise that he succeeded in covering the whole ground the very first thing.

So they once more left the porch, though both boys looked down the lane before going in, to make sure that the queer little butterfly collector was not coming in time to interfere with their immediate plans.

Sallie was just tidying up the diningroom when they found her. The good woman of the house seemed to have gone into the kitchen, where she was preserving some sort of fruit, or making catsup, to judge from the fragrant odors that came floating out from that part of the farmhouse.

Naturally Sallie was only too willing to enter into conversation again with two such attractive looking and bright boys as Frank and Andy Bird. She must have been aware of the fact that they were favorites among the girls of Bloomsbury; and of course also knew something about their being aviators, although both or 'them had shunned that subject carefully while at the dinner table.

And so Frank managed to gradually steer the conversation around to the subject of bug collection. He told of a friend he once had who was "daffy" along that line, and would rather capture some queer looking old night-flying hairy moth, with a death's-head sign on his front, than enjoy the finest supper, or listen to the best play.

That allowed Andy to venture the suggestion that he had taken considerable interest in butterflies himself, and always wanted to see a collection that was worth while. Of course he did not have to explain that the only interest he ever did have in the matter was when, as a very small boy, he used to chase after the fluttering insects as they went from flower to flower, until shown by his mother how cruel it was to destroy the life of such wonderfully beautiful things, that he could not restore again.

Sallie took the bait, Andy knew from the eager light that flashed upon her face. And when he saw her step over to a window, and look quickly down the lane, he turned to his cousin, and made a grimace as much as to say, "See how she fell to my little game, will you, old fellow?"

"Well," said Sallie, flitting back again, "Professor Whitesides hasn't got a very large collection; and the new specimens he gathers day after day he kept in some place, because he has no time just now to do anything with them, he says; but come up with me, and I'll show you the little case he brought with him."

"Sure we will, and I'm glad of the chance to see what valuable butterflies look like," Andy went on to remark.

"He says this little collection is a very rare one, and worth an awfully large sum of money," Sallie went on to remark, in something of a confidential tone, as if getting the boys ready to be surprised when they looked upon the possessions of the industrious professor. "And oh! if you could only hear all the queer things he's been telling us that happened to him in foreign lands, when he was spending ever so much money, and long weary months, finding these very rare specimens. Why, I just stand there, and look at them, and wonder how people can be so foolish, when it seems to me I've seen much prettier butterflies right out there in our fields where the thistles are blooming."

It seemed that the room they had given the wonderful man of science was on the ground floor, and opened off the parlor.

The two boys followed Sallie in, and noted her rather awed manner 5 evidently the professor, whether he turned out to be a fraud or the genuine article, had succeeded in arousing both her admiration and wonder.

The room was plainly yet comfortably furnished, but evidently the professor, like so many other learned savants, did not know such a thing as "order" existed, for things were simply topsy-turvy.

"He just won't let us sweep in here, or do the least thing," explained Sallie, as if she feared the boys would blame her for the looks of the room, "you know, he's so queer, and he says we might lose something that he valued very highly, thinking it was not worth keeping. But here's the little case containing those almost priceless specimens he collected abroad."

She led them to a table on which a small case rested, leaning against the wall. Frank took one look. Apparently the sight affected him strangely, for immediately he bent over closer as though to feast his eyes on those costly trophies which the college professor had collected in foreign lands.

Andy saw that his cousin was evidently having some sort of a silent laughing fit, for he shook all over though not uttering a single sound.

"What ails you, Frank?" he whispered, taking advantage of Sallie having to hurry out of the room, as her mother's voice was heard calling her in the kitchen.

"I'm tickled to death to meet an old friend again, that's all," replied Frank.

"Do you mean to tell me you've seen this wonderful collection before?" demanded the other, like a flash, as it were.

"I most certainly do; and if you stop to think, Andy, I guess you'll say the same; or perhaps, now, you didn't happen to examine the case as closely as I did, that day last spring when we crossed over to Cranford, to pick up a few rare stamps for our collection at Snyder's old curio store."

"Why, bless me, I really believe you're right; I seem to remember seeing it in the show window, now, when we were looking at the little baskets of coins," Andy hastened to remark.

"There isn't the least shadow of a doubt about it," added Frank. "Some time or other, when the notion came to this man to play the part of a butterfly collector, which perhaps the sight of the things brought to his mind, he just stepped into Snyder's store, and bought the old collection. Why, it hasn't got a single specimen that you can't find a thousand of, any day you look, through August and September."

"Right around here, you mean, Frank?"

"Right on this farm, in fact," replied the other, with a wide grin. "Think of the nerve of this learned scientist bringing this here, and telling that it represented the results of years of difficult research? You don't wonder, now, that I just had to snicker, do you, Andy?"



CHAPTER XIV

A CLUE

"That looks bad, don't it Frank?" Andy went on to remark, as he first glanced at the bogus collection of rare specimens, and then eyed his cousin humorously.

"One thing is sure, no man would go to the trouble and expense of buying even a dollar case of common butterflies unless he had some deep object in view, and you know that, Andy. This so-called professor must be a fraud, even if he doesn't turn out to be the man we think he is. Perhaps, he wanting to find out whether Hoskins had discovered that wonderful gold mine. Well, you needn't grin about it because stranger things have happened, I guess, now."

Andy ceased laughing and turned to look around the room.

"I wonder—" he began, and then stopped short.

"Now I can finish your sentence for you," said Frank. "You wonder if we could make any important discovery if we looked around here a bit, while Sallie is helping her ma do up some fruit jars or something like that?"

"Perhaps it wouldn't be just the right thing," suggested Andy, in confusion.

"Under ordinary conditions it certainly wouldn't," his cousin went on to say; "but when you've got a pretty good idea that you're dealing with a slippery hobo, actor, past-aviator, and now a bank burglar and cracksman in general, why that puts a different face on the matter, don't you see, my boy?"

"All right; let's take a look," said Andy, easily convinced that since they were really working hand in glove with the police authorities, they had a perfect right to prowl around in anybody's room, and pick up such valuable information as could be found afloat.

But after all they found nothing that looked like incriminating evidence. The fact of the matter was that the professor did not seem to own any sort of wardrobe whatever, and had nothing belonging to him save the clothes on his back, the little case of butterflies which Frank believed he had bought for a dollar over in Cranford at the curio dealer's shop, and a few bottles holding some strong smelling acids, which possibly were used to either kill the captured butterflies so they would not beat their wings out; or else to preserve certain specimens of bugs he expected to run across in his hunts.

"Nothing doing," said Andy, with considerable of disgust and disappointment in his voice.

"Come here!" remarked his cousin, softly.

"Hello! don't tell me you've found something?" and Andy crossed the floor in more or less haste.

He found Frank bending over a table at which there were writing materials—pen, envelopes, paper and a blotter.

"What's doing? Have you found the gentleman's notebook lying carelessly around, and which we can peep into, eh, Frank?"

"Not at all," came the reply. "I was only looking at this blotter."

"Whatever is there funny about that?" demanded the other, in puzzled tones, as he glanced first at the object in question, and then up at the face of his chum.

"It was a new one, or nearly so, you see! and somebody has been writing heavily, and then pressing the blotter over it," Frank went on.

"And if you could read backwards now, you might make out what they said; is that it, Frank?"

"Oh! that part is as easy as falling off a log. I held it up to the looking glass here. See if you can make it out, Andy."

Hardly had the other looked than he started to read, interjecting remarks of his own as he proceeded.

"Some words missing, looks like, Frank; let's see; 'Car on siding——'rive at 11 P.M. Wed. He says keep low, and trust to him—throw—track. Mum.' That's all I can make out, because he didn't sign any name, it seems. Whatever do you make of all that stuff, Frank?"

First of all Frank pulled out a pencil and copied the marks upon a piece of paper, which he thrust into his pocket.

"He might miss the blotter if I cribbed it, and take the alarm," he explained, as he hastened to put the article in question back on the table, lest Sallie come in at any minute and discover what they were doing, taking liberties in the room of the boarder; and then she would have to be told everything, which might work out badly, Frank feared.

"But I reckon you've got some sort of idea what that writing means, Frank?" pursued the other Bird boy, who, once he started on a subject could no more be shaken off than a bulldog.

"Of course I have, and it's given me something of a shock, too, let me tell you, Andy. First of all, you may know that this very day is Wednesday."

"The day he mentions there; to be sure it is. But Frank, can all this have some reference to another crime they mean to commit?"

"I'm afraid it does," came the reluctant reply.

"Tell me what he means by 'car, siding, track, mum,' and all that. Of course I can understand that he warns the fellow he's sending the message to to keep quiet. What car can he mean? Do you think they aim to steal some one's expensive car now—that they've gone and wrecked Percy's biplane, and must have another means for getting away?"

But Frank simply shook his head at that.

"Oh! you're away off your base there, Andy. He speaks of a car on a siding, and that can only refer to a railroad car. Now, I happen to know that they expect the pay-car to be along some time today or tonight, and it always lies there on that Jeffreys Siding, until they've passed out thousands of dollars to the men who call Bloomsbury their headquarters. Do you see now what it must mean, Andy?"

Andy gasped, and then exclaimed.

"Once more you've gone and seen through the riddle that knocked me silly, Frank. That's just what it must mean—the pay-car would offer fat pickings, all in cash; and they've held up their flight to Canada just to try and gobble it. Oh! what a slick game, with Todd giving false information, and perhaps just leading the police further and further away from Bloomsbury tonight, so as to leave the pay-car next to unprotected. Yes, and doesn't he go on like this, 'he says keep low, and trust to him'? That must mean Todd, don't you think?"

"I read it that way," replied his cousin tersely, as he rubbed his chin in a reflective fashion; for they were now grappling with a dangerous problem, and Frank was only too well aware of the fact that a slip might upset all calculations, as well as possibly endanger their lives; since they were dealing with reckless men, and no boyish rivals like Percy Carberry and Sandy Hollingshead.

"Do you think this was meant for the other one of the bank thieves?" Andy went on to ask.

"It could hardly have been for any one else, Andy. There must have been more to the letter, but the rest dried before he blotted it."

"And that fellow is in hiding somewhere, perhaps watching the biplane, and ready to fight before letting it be retaken, because they depend on it for their get-away to the great lakes and Canada;" Andy further observed.

"Yes, just as you say," the other remarked.

"And now since we've learned this much, Frank, what are we going to do about it—try and find where the stolen biplane is, and do something so as to make it no good for their purpose; or just slip away, go round a little like we were just out for a spin, and getting back to Bloomsbury, put them wise?"

"Neither, just yet anyhow," the older Bird boy remarked. "Not the first, because it would be taking big chances, if, as we believe, one of the robbers is concealed near where the stolen biplane may happen to be lying, partly hidden with dead leaves, so it couldn't be noticed from above; and he would be apt to do something we'd find unpleasant. And as for going back and telling, we'll have to be mighty careful there."

"And why, Frank?"

"Well, to begin with, even the walls have ears, they say; and if the police were suddenly called back from their hunt to the southwest, the fact might get to the robbers; and you know what would happen then."

"Oh!" said Andy, shrugging his shoulders, "I suppose they'd just throw this second job up, and cut stick for Canada, as fast as they could make the aeroplane spin, which would be too bad for Chief Waller, and Joe Green, and the rest of that bunch at Headquarters, who are already figuring on how they'll spend their reward money they hope to get when the bank pays for rounding-up the two thieves."

"But, perhaps, if we just told our fathers, Andy, they might get a few bold men together and lay a beautiful trap for the fellows so that when they broke into the pay-car, they would be made prisoners."

"Bully idea, that, Frank, and I hope you decide to carry it out. Just to think what a pleasant surprise it would be for our butterfly collector, expecting that he was going in to gather in another lot of plunder, and then to hear a voice say to him: 'Hands up! you're our prisoners!' Oh! wouldn't I like to be Johnny-on-the-spot when that happens. Wonder if they wouldn't let us have a part in the proceedings, after we brought the news that upset the plans of the yeggmen?"

"That will do for just now, Andy, because here comes Sally again. Let's be gaping at the wonderful collection that almost cost the professor his very life in all sorts of hot countries, as well as a whole pocket full of money—if you don't care what you say."

And when the farmer's daughter did enter the room a minute later, she saw the two boys standing there, a rapt look of admiration and envy on their faces, as they stared at the little case of common local butterflies which possibly some boy had gathered together, and then disposed of for a song.

While the young aviators had in this fashion about decided on their plan of action, they saw no reason for any hurry. The day was still long, and when they felt like starting toward home it would take them but a very short time to get there.

Meanwhile, there seemed to be some sort of fascination holding them to the neighborhood of the Hoskins' farm. And when they went away a little later it would be with the idea of hanging about, and seeing if the odd little professor might not come along. Both of them thought they would like to look at him. The man who was capable of playing such a clever game as this must surely be worth seeing.

Then again, the fact that Casper Blue once upon a time had been a daring birdman had something to do with this interest on the part of Frank and his cousin, because there is always a certain fellow feeling between those who are engaged in the same dangerous pursuits. But possibly Andy on his part was hoping secretly that by spying around they might be able in some way to learn where the yeggmen had hidden the plunder they had taken from the looted Bloomsbury bank.



CHAPTER XV

WHEN CASPER CAME BACK

Although the Bird boys had more than once before proved that they possessed all the courage and daring a successful aviator must have in order to accomplish the difficult tasks hourly presented to him for solution, it must not be thought that they were reckless to any degree.

Andy might be slightly inclined that way, but Frank was an exceedingly careful navigator of the air, and by degrees his influence was even affecting his younger cousin, as example always will.

When, however, a situation suddenly arose that absolutely required a display of daring, these young air pilots were "there with the punch," as Andy termed it. They had learned how to volplane earthward from a dizzy height with absolute safety, when conditions were just right, and necessity required a quick descent. On a few occasions Frank had even been known to hazard what is known as the "death dip;" but it was only when there happened to be a good reason for taking such chances, and not merely in a spirit of dare-deviltry, such as many show aviators employ, just to send a shiver of dread through the spectators, and then laugh recklessly at the fears their boldness had aroused.

Of course they might have decided to immediately return to Bloomsbury, and give information concerning the extent of their discoveries since coming to the Hoskins' farm.

Perhaps that would have been the wisest move they could make but both boys were rather opposed to carrying it out just then.

The afternoon was wholly before them, and who could tell what change of plans the two yeggmen might make before the coming of the night? Should they get wind of the presence of the Bird boys in the vicinity possibly they would take alarm, and hurrying to their concealed biplane make for the far North with all haste; and in this way, if no one knew of their departure the intended ambuscade that night in the vicinity of the railroad pay-car would be laid in vain.

That was really what the boys feared the most—that their quarry slip off in secret, when they were far away.

Frank was indeed trying to figure out whether it would not be best after all for him to stay by the hydroplane, on guard as it were, while Andy, by using a horse, if the Hoskins happened to still possess such an animal, managed to get to another farm, where they were up-to-date enough to have a telephone in the house, by means of which he could get in touch with Dr. Bird or Judge Lawson in Bloomsbury.

Then again, there was always a slight chance that this pretended professor might have seen them descend, while he was wandering around. Once an airman, and just by instinct as it were, the eyes are almost constantly searching the heavens, perhaps for a glimpse of other adventurous craft, or it may be, signs that give warning of treacherous winds, gathering storms, or similar things that must always be of intense interest to an aviator.

And so while Casper Blue had long since given up taking hazards in a flying machine to indulge in even more dangerous business as a bank robber, still habits would cling tightly, and thus he might have seen more than the ordinary man could have done.

Of course, even though he sought the hydroplane, and found it lying there in the field, he could not very well make any use of it so long as Frank held the missing part in his possession.

But he could in a spirit of maliciousness so utterly destroy the planes, and even injure the powerful little Kinkaid engine that it would be practically fit only for the scrap-heap afterwards. And that was giving Frank more or less concern, even while he continued to linger at the farmhouse because Andy wished to prowl around a little while longer in hopes of getting some clue to the location of the cache where the thieves had hidden their plunder.

Sallie saw nothing strange in this apparent desire of Andy to hang around. She was rather a pretty little thing, and of course knew it; so that she may have believed the witchery of her attractions had more or less to do with the matter.

Even when Frank asked so many queer questions about the absent boarder, Sallie was not wise enough to understand that the boys Were much more concerned about how Professor Whitesides amused himself, where his favorite lounging places seemed to be, and all that, rather than in her pretty face and merry laugh.

Her mother must have counted on having her assistance in carrying on her task of putting up preserves in the kitchen, for once more she called to Sallie to come and lend a hand for a few moments.

This left the two boys alone again, and gave them a chance for exchanging views, which they were not slow to do.

"I guess he doesn't keep it around here, in this room, or anywhere close by," was Andy's first remark.

Frank chuckled on hearing this.

"Oh! I see that you've got your mind set on recovering what was taken from the bank. You're a mercenary fellow, Andy. But, then, since our fathers have more or less interest in the same bank, which is going to be mighty badly crippled if the cash and securities are not recovered sooner or later, why, I can't blame you much. I'd like to run across the loot myself, more than I can tell you."

"I'm only afraid that if the men are taken prisoners to night, when they come to clean out the pay-car after it arrives in Bloomsbury, they'll not have this other stuff with them, and will refuse to tell where it's hidden. That will be just as bad for the bank as if they'd got away to Canada with the swag, as the Chief calls it. I wish I knew how we could track this Casper Blue to where the other yegg is hiding near the biplane, and watch them until we saw where they had the cache. After that we could just hang around, and when they started in a power-boat perhaps for Bloomsbury, with Todd Pemberton at the wheel, we could do something to make the biplane useless to them, and then toward evening put for home ourselves."

Frank listened while the other ran all of this off, and evidently he was more or less amused at what he heard.

"It's plain to be seen that you've been doing some tall thinking and planning all this while, Andy," he remarked.

"But you'll admit, I guess, that if there was any way to carry out my scheme, it would be a jim dandy idea," the other persisted.

"Of course; but that's where the trouble lies. Even if Casper did come back, we never could track him through the woods and around the swamps without his sooner or later discovering that he was being followed, because we're not clever at that sort of thing. And once he got wind of our being after him, chances are he'd lay some trap with his mate, into which both of us would tumble headlong."

Andy scratched his head, and a look of doubt came upon his face.

"H'm! I wouldn't like that one little bit, and that's a fact, Frank," he admitted, candidly. "If we fell into their hands and were kicked around and then left tied up like a pair of mummies from the pyramids of Egypt, while they went and cleaned out that pay-car, and sailed away for Canda—oh! excuse me, if you please. Anything but that. The laugh would sure be on the Bird boys. I don't mind posing once in a while as a hero; but it would jar me a whole lot to know that people were pointing me out, and telling how nicely these wonderful Bird boys had been taken in and done for by a couple of traveling yeggs. Have it your own way, Frank, and don't pay any attention to my silly schemes.

"Your ideas are all right, Andy, but the only trouble is they are too strong for a couple of boys to carry out. I think we'd be wise to play safe. More games are won in the long run that way, than by being dashing and venturesome."

"Of course you're right, and as I've had my little fling, and got it out of my system, let's work along the sensible lines you laid out, Frank."

That was just like Andy. He might occasionally seem to yearn to break loose, and take a wild flight, but on second sober thought he nearly always came back to his cousin's way of thinking.

Sallie still remained in the kitchen, so that they were able to keep on talking without any fear of being interrupted or overheard.

"I'm wondering if Percy will ever have the chance to handle his Farman biplane again," Andy went on to remark. "He seemed to set a great store by it to offer such a nice fat reward for its return. And it's so brand new that he hasn't had much of a chance to try it out. Wasn't he mad, though, when he came racing along in that car looking for Chief Waller. He looked as red as a turkey gobbler. Just to think that while he was up there with three of his cronies trying to injure our machine, those yeggs were fixing it all up so that they could get his biplane, if they missed ours. It's a rich joke on Perc."

"Oh! I hope he gets it back again safe and sound," said Frank. "Life would be rather tame for us around home here, if we didn't have Percy to think about. For a long time, now, he's kept us guessing, and we'd feel a little lonely if he gave up flying."