THE MARKED BILL.

Some two days after the events narrated in our last chapter, Lieut. Bradbury, sitting in the library of the New York Aero Club, on West Fifty-fourth Street, received a telegram from Eugene Mortlake. He was considerably astonished, when on tearing it open, he read as follows:

"Must see you at once. Have positive proof that young Prescott is about to sell out his secrets to foreign government."

"Phew!" whistled the young officer. "This is a serious charge. If it is proved, it will bar Prescott from bidding for the United States government contract. But I can hardly believe it. There must be some mistake. However, it is my duty to investigate. Let's see—three o'clock. I can get a train to Sandy Beach at four. Too bad! Too bad!"

The young officer shook his head. He had come to have a sincere regard for Roy and his pretty sister, as well as admiration for their resourcefulness and pluck.

When it is explained that during the time elapsing between his lucky lift in the Prescott machine and the reception of the note, that Lieut. Bradbury had notified Roy that he would be expected to report at the Brooklyn Navy Yard, his feelings on learning that there was suspicion directed against his young protegé, may be imagined. Mortlake, too, had received a notice that his machines were eligible for a test, so that there would have seemed to be no object for his acting treacherously. Otherwise, the young officer might have been suspicious. What he had seen of Mortlake had not particularly elevated that gentleman in his opinion. But if he had desired to wrong the Prescotts, reasoned the officer, such a resourceful man as he had adjudged Mortlake to be, would have sought a deeper and more subtle way of going about it.

"And I'd have staked my word on that boy's loyalty; aye, and on his sister's too," muttered the officer, as he made ready for his hasty trip to Long Island.

By this it will be seen that Lieut. Bradbury was by no means proof against the rather common failing of inclining to believe the first evil report we hear. It is a phase of human nature that is not combatted as it should be.

In the meantime, Roy and Peggy had sustained a surprise, likewise. The day before that on which Lieut. Bradbury received the disturbing dispatch, an automobile had whizzed up to their gate and stopped. Roy, Peggy and Jess and Jimsy were at a game of tennis, when a rather imperious voice summoned them, from the tonneau of the machine.

They looked up, to see a remarkably pretty young girl, who could scarcely have been more than eighteen years old. Her eyes were black as sloes, and flashed like smoldering fires. A great mass of hair of the same color was piled on the top of her head in grown-up fashion, and her gown, of a magenta hue, which set off her dark beauty to perfection, was cut in the most recent—too recent, in fact—style.

"Can you direct me to Mr. Mortlake's aeroplane factory?" she demanded in an imperious tone. Evidently the flushed, healthy-looking young people, who had been playing tennis so hard, were very despicable in her eyes.

"There it is, down the road there," volunteered Roy. "It's that barn-like place."

The appellation was unfortunate. The girl's eyes flashed angrily.

"My name is Regina Mortlake," she said angrily. "I am Mr. Mortlake's daughter. He is not in the habit of putting up barns, I can assure you."

"I beg your pardon——" began Roy, quite taken aback by the extraordinary energy with which the reproof to his harmless remark had been given. But the dark-eyed beauty in the automobile had given a quick order to the chauffeur, and the car skimmed on down the road.

Later that day the Silver Cobweb ascended for a flight. It had nothing more the matter with it on the day of the break-down than the heated cylinders, which, as Mortlake had prophesied, soon cooled. But Mortlake himself did not take up the silvery aeroplane on this occasion. A new figure was at the wheel, clad in dainty dark aviation togs and bonnet, with a fluttering, flowing veil of the same color, which streamed out like a flag of defiance.

The new driver was Miss Regina Mortlake.

They learned later that the girl had taken frequent flights in the South, where her father had, for a time, entered into the business of giving aeroplane flights for money at county fairs and the like. His daughter had taken naturally to the sport, and was an accomplished air woman. She knew no fear, and her imperious, ambitious spirit made her a formidable rival even to the foreign flying women who competed at various international aviation meets.

While his daughter spun through the air, Eugene Mortlake sat in his little glass-enclosed office in one corner of the noisy aeroplane plant. Four finished machines were now ready, and he would have felt capable of facing any tests with them had it not been for his uneasy fear of the Prescott aeroplane. But he had evolved a scheme by which he thought he would succeed in putting Peggy and Roy out of the race altogether. It was in the making that afternoon in the little office.

Opposite to Mortlake sat two men whom we have seen before. But in the cheap, but neat suits they now wore, and with their faces clean-shaven of the growth of stubby beard that had formerly covered them, it would have been somewhat difficult to recognize the two ill-favored tramps who had been routed by Peggy in such a plucky manner. But, nevertheless, they were the men.

"You thoroughly understand your instructions now?" questioned Mortlake, as he concluded speaking.

The fellow who had been addressed by his companion as Joey, at the time they encountered Mortlake and Harding on the road to the Galloway farm, nodded.

"We understand, guv'ner," he rasped out in a hoarse voice; "Slim, here, and me don't take long ter catch on, eh, Slim?"

"No dubious manner of doubt about that," responded Slim. "An' although I'm a tramp now, guv'ner, I wasn't allers one. I've held my head as high as the rest of the good folks of the world. I can play the gentleman to perfection. Don't you worry."

This Slim—or to give him his correct name—Frederick Palmer, was, as he declared with such emphasis, a man who had indeed "seen better days," as the phrase is. Now that he was invested in fair-looking clothes, and was graced with a clean collar and a smooth-shaven face, he actually might have passed for a person in fairly well-to-do circumstances. For the part Mortlake wished him to play, he could not have picked out a better man. Utterly unscrupulous, and with the best of his life behind him, "Slim"—as the tramp fraternity knew him—was prepared to do anything that there was money in. His companion possessed no such saving graces of appearance. Short, coarse, and utterly lacking in every element of refinement, Joey Eccles was a typical hobo. But Mortlake's shrewd mind had seen where he could make use of him, too, in the diabolical plan he was concocting, and the details of which he had just finished confiding to his unsavory lieutenants.

"But say, guv'ner," struck in Joey Eccles, his little pig-like eyes agleam with cupidity, "we've got to have a bit more of the brass, you know—a little more money—eh?"

He ended in an insinuating whine, the cringing plea of the professional beggar.

Mortlake made a gesture of impatience.

"I gave you fellows a twenty-dollar-bill a few days ago," he said, "in addition to that, you've been provided with clothes and lodging. What more do you want?"

"We've got to have some more coin, that's flat," announced Slim decidedly; "come on, fork over, guv'ner. You've gone too far into this now to pull out."

Mortlake's florid face went white. As if he heard it for the first time, the words struck home. He had indeed "gone too far," as the tramp sitting opposite to him had said. He was, in fact, completely in the power of these two unscrupulous mendicants. Making a resolve to get rid of them as speedily as possible, he dived into his breast pocket and drew from it a roll of bills that made Slim's and Joey's eyes stick out of their heads.

He peeled off a twenty-dollar-bill, and flung it with no good grace down upon the table.

"There," he said, "that's the last you'll get till the trick is done."

"Thankee, guv'ner; I knowed you'd see sense. A man of your intelligous intellect, and——"

"That will do," snapped Mortlake. "Do you think I've got nothing to do but talk to you fellows all day? You thoroughly understand, now, to-morrow night on the road to Galloway's farm?"

"Yus, and we've got a nice little deserted farm house all picked out, where we can keep the young rooster on ice," grinned Joey.

"Well, well," shot out Mortlake, "that will be your task. I've nothing to do with that. Do you understand," he rapped the table nervously, "I know nothing about it."

"All right, all right; we're wise," Slim assured him confidently. "Don't you worry. Come on, Joey. Got the money?"

"Have I? Oh, no; I'm goin' ter leave it right here," grinned Joey, enjoying his own irony hugely.

Still chuckling, he arose and shuffled out, followed by the unsavory Slim.

Outside, and on the road to the village, Slim began to be obsessed by doubts.

"Some way, I don't jes' trust that Mortlake," he said. "You're sure that bill is all right, Joey?"

"Sure? Well, you jes' bet I am. Here, look at it yourself. All right, ain't it?"

He drew out the bill and handed it to Slim for his inspection.

"And the best of it is," he chuckled, while Slim inspected the bill carefully, "the best of it is, that I wasn't conformin' to the exact truth when I told Mortlake that we'd spent all the other coin. I've got the best part of it left."

"Good," grunted Slim, turning the twenty-dollar-bill over and examining the reverse side, "that being the case—hullo!"

"What's up?" asked Joey.

For reply Slim handed the bill to Joey, pointing with a grimy first finger at something on the reverse side.

It was an "O," scrawled in dull red ink.

"That would be an easy bill to identify," commented Palmer, uneasily, "wonder if this can be a trap?"

"Well, keep your suspicions to yourself for a while," counseled Joey; "we don't need to break it till we make sure."