"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 bra.s.s b.u.t.tons, 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.

"h.e.l.lo! 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. h.e.l.lo! 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 a.s.surance 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