"Let her go!" cried Tom as he turned on more gasoline and further advanced the spark of the motor. The roar increased, the propeller looked like a solid circle of wood, and the trim little monoplane moved slowly across the rising ground, increasing its speed every second, until, like some graceful bird, it suddenly rose in the air as Tom tilted the wing tips, and soared splendidly aloft!



Chapter Ten

A Midnight Intruder

Tom Swift sent his wonderful little craft upward on a gentle slant. Higher and higher it rose above the ground. Now it topped the trees; now it was well over them.

On the earth below stood Mr. Swift, Mr. Jack son, Eradicate and Mrs. Baggert. They were the only witnesses of the trial flight, and as the aged inventor saw his son's latest design in aeroplanes circling in the air he gave a cheer of delight. It was too feeble for Tom to hear, but the lad, glancing down, saw his father waving his hand to him.

"Dear old dad!" thought Tom, waving in return. "I hope he's well enough to see me win the big prize."

Tom and Mr. Damon went skimming easily through the air, at no great speed, to be sure, for the young inventor did not want to put too sudden a strain on his motor.

"This is glorious!" cried the odd gentleman. "I never shall have enough of aeroplaning, Tom!"

"Nor I, either," added his companion. "But how do you like it? Don't you think it's an improvement on my Butterfly, Mr. Damon?"

"It certainly is. You're a wonder, Tom! Look out! What are you up to?" for the machine had suddenly swerved in a startling manner.

"Oh, that's just a new kind of spiral dip I was trying," answered Tom. "I couldn't do that with my other machine, for I couldn't turn sharp enough."

"Well, don't do it right away again," begged Mr. Damon, who had turned a little white, and whose breath was coming in gasps, even though he was used to hair-raising stunts in the frail craft of the air.

Tom did not take his machine far away, for he did not want to exhibit it to the public yet, and he preferred to remain in the vicinity of his home, in case of any accident. So he circled around, did figures of eight, went up and down on long slants, took sharp turns, and gave the craft a good tryout.

"Does it satisfy you?" asked Mr. Damon, when Tom had once more made the spiral dip, but not at high speed.

"In a way, yes," was the answer. "I see a chance for several changes and improvements. Of course, I know nothing about the speed yet, and that's something that I'm anxious about, for I built this with the idea of breaking all records, and nothing else. I know, now, that I can construct a craft that will successfully navigate the air; in fact, there are any number of people who can do that; but to construct a monoplane that will beat anything ever before made is a different thing. I don't yet know that I have done it."

"When will you?"

"Oh, when I make some changes, get the motor tuned up better, and let her out for all she's worth. I want to do a hundred miles an hour, at least. I'll arrange for a speedy flight in about two weeks more."

"Then I think I will stay home," said Mr. Damon.

"No; I'll need you," insisted Tom, laughing. "Now watch. I'm going to let her out just a little."

He did, with the result that they skimmed through the air so fast that Mr. Damon's breath became a mere series of gasps.

"We'll have to wear goggles and mouth protectors when we really go fast!" yelled Tom above the noise of the motor, as he slowed down and turned about for home.

"Go fast! Wasn't that fast?" asked Mr. Damon.

Tom shook his head.

"You wait, and you'll see," he announced.

They made a good landing, and Mr. Swift hastened up to congratulate his son.

"I knew you could do it, Tom!" he cried.

"I couldn't, though, if it hadn't been for that wonderful engine of yours, dad! How do you feel?"

"Pretty good. Oh! but that's a fine machine, Tom!"

"It certainly is," agreed Mr. Jackson.

"It will be when I have it in better trim," admitted the young inventor modestly.

"By golly!" cried Eradicate, who was grinning almost from ear to ear, "I's proud oh yo', Massa Tom, an' so will mah mule Boomerang be, when I tells him. Yes, sah, dat's what he will be—proud ob yo', Massa Tom!"

"Thanks, Rad."

"Well, some folks is satisfied with mighty little under 'em, when they go up in the air, that's my opinion," said Mrs. Baggert.

"Why, wouldn't you ride in this?" asked Tom of the buxom housekeeper.

"Not if you was to give me ten thousand dollars!" she cried firmly. "Oh, dear! I think the potatoes are burning!" And she rushed back into the house.

The next day Tom started to work overhauling the Humming-Bird, and making some changes. He altered the wing tips slightly, and adjusted the motor, until in a thrust test it developed nearly half again as much power as formerly.

"And I'll need it all," declared Tom as he thought of the number of contestants that had entered the great race.

For the Eagle Park meet was to be a large and important one, and the principal "bird-men" of the world were to have a part in it. Tom knew that he must do his very best, and he spared no efforts to make his monoplane come up to his ideal, which was a very exacting one.

"We'll have a real speed test to-morrow," Tom announced to Mr. Damon one night. "I'll see what the Humming-Bird can really do. You'll come, won't you?"

"Oh, I suppose so. Bless my insurance policy! I might as well take the same chance you do. But if you're going to have such a nerve-racking thing as that on the program, you'd better get to bed early and have plenty of sleep."

"Oh, I'm not tired. I think I'll go out this evening."

"Where?"

"Oh, just around town, to see some of the fellows." But if Tom was only going around town merely to see his male friends, why did he dress so carefully, put on a new necktie, and take several looks in the glass before he went out? We think you can guess, and also the girl's name.

The young inventor got in rather late, and after a visit to the aeroplane shed, to see that all was right there, he went to bed, first connecting up the burglar-alarm wires that guarded the doors and windows of the aerodrome.

How long he had been asleep Tom did not know, but he was suddenly awakened by hearing the buzzing of the alarm at the head of his bed. At first he took it for the droning and humming of the aeroplane motor, as he had a hazy notion, and a sort of dream, that he was in his craft.

Then, with a start, he realized what it was—the burglar alarm.

"Some one's in the shed!" he gasped.

Out of bed he leaped, drawing on his trousers and coat, and putting on a pair of slippers, with speed worthy of a fireman. He grabbed up a revolver and rushed from his room, pounding on the door of Mr. Jackson's apartment in passing.

"Some one in the shed, after the Humming-Bird!" shouted Tom. "Get a gun, and come down!"



Chapter Eleven

Tom Is Hurt

As Tom passed down the hall on his way to the side door, from which he could more quickly reach the aeroplane shed, he saw his father coming from his room.

"What's the matter? What is it?" asked Mr. Swift, and alarm showed on his pale face.

"It's nothing much, dad," said the youth, as quietly as he could, for he realized that to excite his father might have a bad effect on the invalid.

"Then why are you in such a hurry? Why have you that revolver? I know there is something wrong, Tom. I am going to help you!"

In his father's present weakened state Tom desired this least of all, so he said:

"Now, never mind, dad. I thought I heard a noise out in the yard, and I'm not going to take any chances. So I roused Mr. Jackson, and I'm going down to see what it is. Perhaps it may only be Eradicate's mule, Boomerang, kicking around, or it may be Rad himself, or some one after his chickens. Don't worry. Mr. Jackson and I can attend to it. You go back to bed, father."

Tom spoke with such assurance that Mr. Swift believed him, and retired to his room, just as the engineer, partly dressed, came hurrying out in response to Tom's summons. He had his rifle, and, had the invalid inventor seen that, he surely would have worried more.

"Come on!" whispered Tom. "Don't make any noise. I don't want to excite my father."

"What was it?" asked the engineer.

"I don't know. Burglar alarm went off, that's all I can say until we get to the shed."

Together the two left the house softly, and soon were hurrying toward the aeroplane shed.

"Look!" exclaimed Mr. Jackson. "Didn't you see a light just then, Tom?"

"Where?"

"By the side window of the shed?"

"No, I didn't notice it! Oh, yes! There it is! Some one is in there! If it's Andy Foger, I'll have him arrested, sure!"

"Maybe we can't catch him."

"That's so. Andy is a pretty slippery customer. Say, Mr. Jackson, you go around and get Eradicate, and have him bring a club. We can't trust him with a gun. Tell him to get at the back door, and I'll wait for you to join me, and we'll go in the front door. Then we'll have 'em between two fires. They can't get away."

"How about the windows?"

"They're high up, and hard to open since I put the new catches on them. Whoever got in must have forced the lock of the door. There goes the light again!"

As Tom spoke there was seen the faint glimmer of a light. It moved slowly about the interior of the shed, and with a peculiar bobbing motion, which indicated that some one was carrying it.

"Go for Eradicate, and don't make any more noise than you can help in waking him up," whispered Tom, for they were now close to the shed, and might be heard.

Mr. Jackson slipped off in the darkness, and Tom drew nearer to the building that housed his Humming-Bird. There was one window lower than the others, and near it was a box, that Tom remembered having seen that afternoon. He planned to get up on that and look in, before making a raid to capture the intruder.

Tom raised himself up to the window. The light had been visible a moment before he placed the box in position, but an instant later it seemed to go out, and the place was in darkness.

"I wonder if they've gone away?" thought Tom. "I can't hear any noise."

He listened intently. It was dark and silent in the shop. Suddenly the light flashed up brighter than before, and the young inventor caught sight of a man walking around the new aeroplane, examining it carefully. He carried, as Tom could see, a large-sized electric flash-lamp, with a brilliant tungsten filament, which gave a powerful light.

As the youth watched, he saw the intruder place the light on a bench, in such a position that the rays fell full upon the Humming-Bird. Then, adjusting the spring switch so that the light would continue to glow, the man stepped back and drew something from an inner pocket.

"I wonder what he's up to?" mused Tom. "I wish Eradicate and Mr. Jackson would hurry back. Who can that fellow be, I wonder? I've never seen him before, as far as I know. I thought sure it was going to turn out to be Andy Foger!"

Tom turned around to look into the dark yard surrounding the shed. He was anxious to hear the approach of his two allies, but there was no sound of their footsteps.

As he turned back to watch the man he could not repress a cry of alarm, for what the intruder had drawn from his pocket was a small hatchet, and he was advancing with it toward the Humming-Bird!

"He's going to destroy my aeroplane!" gasped Tom, and he raised his revolver to fire.

He did not intend to shoot at the man, but only to fire to scare him, and thus hasten the coming of Mr. Jackson and the colored man. But there was no need of this, for an instant later the two came running up silently, Eradicate with a big club.

"Whar am he?" he asked in a hoarse whisper. "Let me git at him, Massa Tom!"

"Hush!" exclaimed the young inventor. "We have no time to lose! He's in there, getting ready to chop my aeroplane to bits! Go to the back door, Rad, and if he tries to come out don't let him get away."

"I won't!" declared the colored man emphatically, and he shook his club suggestively.

"Come on! We'll go in the front door," whispered Tom to the engineer. "I have the key. We'll catch him red-handed, and hand him over to the police."

Waiting a few seconds, to enable Eradicate to get to his place, Tom and the engineer stole softly toward the big double doors. Every moment the youth expected to hear the crash of the hatchet on his prize machine. He shivered in anticipation, but the blows did not fall.

Tom pushed open the door and stepped inside, followed by Mr. Jackson. As they did so they saw the man standing in front of the Humming-Bird. He again raised the little hatchet, which was like an Indian tomahawk, and poised it for an instant over the delicate framework and planes of the air craft. Then his arm began to descend.

"Stop!" yelled Tom, and at the same time he fired in the air.

The man turned as suddenly as though a bullet had struck him, and for a moment Tom was afraid lest he had hit him by accident; but an instant later the intruder grabbed up his flashlight, and holding it before him, so that its rays shone full on Tom and Mr. Jackson, while it left him in the shadow, sprang toward them, the hatchet still in his hand.

"Look out, Tom!" cried Mr. Jackson.

"Out of my way!" shouted the man.

Bravely Tom stood his ground. He wished now that he had a club instead of his revolver. The would-be vandal was almost upon him. Mr. Jackson clubbed his rifle and swung it at the fellow. The latter dodged, and came straight at Tom.

"Look out!" yelled the engineer again, but it was too late. There was the sound of a blow, and Tom went down like a log. Then the place was in darkness, and the sound of footsteps in rapid flight could be heard outside the shed.

The intruder, after wounding the young inventor, had made his escape.



Chapter Twelve

Miss Nestor Calls

"What's de mattah? Shall I come in? Am anybody hurted?" yelled Eradicate Sampson as he pounded on the rear door of the aeroplane shed. "Let me in, Massa Tom!"

"All right! Wait a minute! I'm coming!" called Mr. Jackson. He tried to peer through the darkness, to where a huddled heap indicated the presence of Tom. Then he thought of the electric lights, which were run by a storage battery when the dynamo was shut down, and a moment later the engineer had switched on the incandescents, filling the big shed with radiance.

"Tom, are you badly hurt?" gasped Mr. Jackson.

There was no answer, for Tom was unconscious.

"Let me in! Let me git at dat robber wif mah club!" cried the colored man eagerly.

Knowing that he would need help in carrying Tom to the house, Mr. Jackson hurried to the back door. He had a key to it, and it was quicker to open it than to send Eradicate away around the shed to the front portals.

"Whar am he?" gasped the faithful darky, as he took a firmer grasp of his club and looked around the place. "Let me git mah hands on him! I'll feed him t' Boomerang, when I gits froo wif him!"

"He's gone," said the engineer. "Help me look after Tom. I'm afraid he's badly hurt."

They hastened to the unconscious lad. On one side of his head was a bad cut, which was bleeding freely.

"Oh! he's daid! I know he's daid!" wailed Eradicate.

"Not a bit of it. He isn't dead, but he may die, if we don't get him into the house, and have a doctor here soon," said Mr. Jackson sternly. "Catch hold of him, Rad, and, mind, don't carry on, and get excited, and scare Mr. Swift. Just pretend it isn't very bad, or we'll have two patents on our hands instead of only Tom."

They managed to get the youth into the house, and, contrary to their fears, Mr. Swift was not nearly so nervous as they had expected. Calmly he took charge of matters, and even telephoned for Dr. Gladby himself, while Mr. Jackson and Eradicate undressed Tom and got him to bed. Mrs. Baggert busied herself heating water and getting things in readiness for the doctor, who had promised to come at once.

Tom was just regaining consciousness when the physician came in, having driven over at top speed.

"What—what happened? Did the Humming Bird fall?" asked Tom in a whisper, putting his hand to his head.

"No, something fell on you, I guess," said the doctor, who had been hurriedly told of the circumstances. "But don't worry, Tom. You'll be all right in a few days. You got a bad cut on the head, but the skull isn't fractured, I'm glad to say. Here, now, just drink this," and he gave Tom some medicine he had mixed in a glass.

The cut was soon dressed, and Tom felt much better, though weak and a trifle dizzy.

"Did he hit me with the hatchet?" he asked Mr. Jackson.

"I couldn't tell," was the engineer's reply, "it all happened so quickly. In another instant I'd have bowled him over, instead of him landing on you, but I just missed him. He either used the hatchet, or some blunt instrument."

"Well, don't talk about it now," urged the doctor. "I want Tom to get quiet and go to sleep. We'll be much better in the morning, but I must forbid any aeroplane flights." And he shook his finger at Tom in warning. "You'll have to lie quiet for several days," he added.

"All right," agreed the young inventor weakly, and then he dozed off, for the physician had given him a quieting medicine.

"Haven't you any idea who it was?" asked Dr. Gladby of Mr. Jackson, as he prepared to leave.

"Not the slightest. It was no one Tom or I had ever seen before. But whoever it was, he intended to destroy the Humming-Bird, that was evident!"

"The scoundrel! I'm glad you foiled him in time; but it's too bad about Tom. However, we'll soon have him all right again."

"I knows who done it!" broke in Eradicate, who was a sort of privileged character about the Swift home.

"Who?" asked Mr. Jackson.

"It were dat Andy Foger. Leastways, he send dat man heah t' make mincemeat oh de Hummin'-Bird. I's positib 'bout dat, so I am!" And Eradicate grinned triumphantly.

"Well, perhaps Andy did have a hand in it," admitted Mr. Swift, "but we have no proof of it, I can't see what his object would be in wanting to destroy Tom's new craft."

"Pure meanness. Afraid that Tom will beat him in the race," suggested Mr. Jackson.

"It's too big a risk to take," went on the aged inventor. "I'm inclined to think it might be one of the gang of men who made the diamonds in the cave in the mountains. They might have sent a spy on East, and he might try to damage the aeroplane to be revenged for what Tom and Mr. Jenks did to them."

"It's possible," agreed the engineer. "Well, we'll wait until Tom can talk, and we'll go over it with him."

"Not until he is stronger, though," stipulated the physician as he went away. "Don't excite Tom for a few days."

The young inventor was much better the following day, and when Dr. Gladby called he said Tom could sit up for a little while. Two days later Tom was well enough to be talked to, and his father and Mr. Jackson went over all the details of the matter. Mr. Damon, who had returned home, came to see his friend as soon as he heard of his plight, and was also a member of the consulting party.

"Bless my dictionary!" exclaimed the eccentric man. "I wish I had been here to take a hand in it. But, Tom, do you believe it was one of the diamond-making gang?"

"I hardly think so," was the reply. "They would take some other means of revenge than by destroying my new aeroplane. I'm inclined to think it was some one who is in with Andy Foger."

"Then we'll hire detectives, and locate him and them," declared Mr. Damon, blessing several things in succession.

Tom, however, did not like that plan, and it was decided to do nothing right away. In another few days Tom was able to be up, though he was still a semi-invalid, not venturing out of the house.

It was one afternoon, when, rather tired of his confinement, he was wishing he could resume work on his air craft, that Mrs. Baggert came in, and said:

"Some one to see you, Tom."

"Is it Mr. Damon?"

"No, it's a lady. She—"

"Oh, Tom! How are you?" cried a girlish voice, and Mary Nestor walked into the room, holding out both hands to the young inventor. Tom, with a blush, arose hastily.

"No! no! Sit still!" commanded the girl. "Oh! I'm so sorry to hear about your accident! In fact, I only heard this morning. We've been away, mamma and I, and we just got back. Tell me all about it, that is, if you feel able. But don't exert yourself. Oh! I wish I had hold of that man!"

And Miss Nestor clenched her two pretty little hands and set her white, even teeth grimly together, as though she would do most desperate things indeed.

"I wish you did, too!" exclaimed Tom. "That is, so you could hold him until I had a chance at him. But I'm all right now. It was very good of you to call. How are you, and how are your folks?"

"Very well. But I came to hear about you. Tell me," and she looked anxiously at Tom, while Mrs. Baggert discreetly withdrew to the adjoining room, and made a great noise, rattling papers and moving chairs about.

Thereupon Tom told what had happened, while Mary Nestor listened interestedly and with expressions of fear at times.

"But if Andy had anything to do with it," concluded Tom, "I can't understand what his object is. Andy is acting very strangely lately. We can't locate him, nor find out where he is building his airship. That's what I want to know; but Mr. Damon and I, after a lot of trouble, only found his aeroplane shed empty."

"And you want to find out where Andy Foger is building his aeroplane which he has entered in the big race?" asked Miss Nestor.

"That's what I'd like to know," declared Tom earnestly. "Only we can't seem to do it. No one knows."

"Why don't you write to Mr. Sharp, or some one of the aviation meet committee?" asked the girl simply. "They would know, for you say Andy made his formal entry with them, and the rules require him to tell from what city and State he will enter his craft. Write to the committee, Tom."

For a moment the young inventor stared at her. Then he banged his fist down on the arm of his chair.

"By Jove, Mary! That's the very thing!" he cried. "I wonder why I never thought of that, instead of fiddling around in disguises, and things like that? I wonder why I never thought of that plan?"

"Perhaps because it was so simple," she answered, with a pretty blush.

"I guess that's it," agreed Tom. "It takes a woman to jump across a bridge to a conclusion every time. I'll write to Mr. Sharp at once."



Chapter Thirteen

A Clash with Andy

Tom lost no time in writing to Mr. Sharp. He wondered more and more at his own neglect in not before having asked the balloonist, when the latter was in Shopton, where Andy was building his aeroplane. But, as it developed later, Mr. Sharp did not know at that time.

While waiting for a reply to his letter, Tom busied himself about his own craft, making several changes he had decided on. He also began to paint and decorate it, for he wanted to have the Humming-Bird present a neat appearance when she was officially entered in the great race.

Miss Nestor called on Tom again, and Mr. Damon was a frequent visitor. He agreed to accompany Tom to the aviation park when it was time for the race, and also to be a passenger in the ten-thousand-dollar contest.

"It must be perfectly wonderful to fly through the air," said Miss Nestor one day, when Tom and Mr. Damon had the Humming-Bird out on the testing ground, trying the engine, which had been keyed up to a higher pitch of speed. "I consider it perfectly marvelous, and I can't imagine how it must seem to skim along that way."

"Come and try it," urged Tom suddenly. "There's not a bit of danger. Really there isn't."

"Oh! I'd never dare do it!" replied the girl, with a gasp. "That machine is too swift by name and swift by nature for me."

"Why don't you take Miss Nestor on a grass-cutting flight, Tom?" suggested Mr. Damon. "Bless my lawn mower! but she wouldn't be frightened at that."

"Grass cutting?" repeated the girl. "What in the world does that mean?"

"It means skimming along a few feet up in the air," answered the young inventor, who had now fully recovered from the effects of the blow given him by the midnight intruder. In spite of many inquiries, no clues to his identity had been obtained.

"How high do you go when you 'cut grass,' as you call it?" asked Miss Nestor, and Tom thought he detected a note of eager curiosity in her voice.

"Not high at all," he said. "In fact, sometimes I do cut off the tops of tall daisies. Come, Mary! Won't you try that? I know you'll like it, and when you've been over the lawn a few times you'll be ready for a high flight. Come! there's no danger."

"I—I almost believe I will," she said hesitatingly. "Will you take me down when I want to come?"

"Of course," said Tom. "Get in, and we'll start."

The Humming-Bird was all ready for a trial flight, and Tom was glad of the chance to test it, especially with such a pretty passenger as was Miss Nestor.

"Bless my shoelaces!" cried Mr. Damon. "I can see where I am going to be cut out, Tom Swift. I'll not get many more rides with you now that Miss Nestor is taking to aeroplaning, you young rascal!" And he playfully shook his finger at Tom.

"Oh, I don't expect to get enthusiastic over it," said Miss Nestor, who, now that she had taken her place in one of the small seats under the engine, appeared as if she would be glad of the chance to change her mind. But she did not.

"Now, if you take me more than five feet up in the air, I'll never speak to you again, Tom Swift!" she exclaimed.

"Five feet it shall be, unless you yourself ask to go higher," was the youth's reply, as he winked at Mr. Damon. Well he knew the fascination of aeroplaning, and he was almost sure of what would happen. "You can take a tape measure along, and see for yourself," he added to his fair passenger. "The barograph will hardly register such a little height."

"Well, it's as high as I want to go," said the girl. "Oh!" with a scream, as Tom started the propeller. "Are we going?"

"In a moment," was his reply. He took his seat beside the girl. The motor was speeded up until it sounded like the roar of the ocean surf in a storm.

"Let her go!" cried Tom to Mr. Damon and Mr. Jackson, who were holding back the Humming-Bird. They gave her a slight shove to over-come the inertia, and the trim little craft darted across the ground at every increasing speed.

Miss Nestor caught her breath with a gasp, glanced at Tom, and noted how cool he was, and then her frantic grip of the uprights slightly relaxed.

"We'll go up a little way in a minute!" shouted Tom in her ear as they were speeding over the level ground.

He pulled a lever slightly, and the Humming-Bird rose a little in the air, but only for a short distance, not more than five feet, and Tom held her there, though he had to run the engine at a greater speed than would have been the case had he been in the sustaining upper currents. It was as if the Humming-Bird resented being held so closely to the earth.

Around in a big circle, back and forth went the craft, at no time being more than seven feet from the ground. Tom glanced at Miss Nestor. Her cheeks were unusually red, and there was a bright sparkle in her eyes.

"It's glorious!" she cried. "Do you—do you think there's any danger in going higher? I believe I'd like to go up a bit."

"I knew it!" cried Tom. "Up we go!" And he pulled the wind-bending plane lever toward him. Upward shot the craft, as if alive.

"Oh!" gasped Mary.

"Sit still! It's all right!" commanded Tom.

"It's glorious; glorious!" she cried. "I'm not a bit afraid now!"

"I knew you wouldn't be," declared the young inventor, who had calculated on the fascination which the motion through the air, untrammeled and free, always produces. "Shall we go higher?"

"Yes!" cried Miss Nestor, and she gazed fearlessly down at the earth, which was falling away from beneath their feet. She was in the grip of the air, and it was a new and wonderful sensation.

Tom went up to a considerable distance, for, once a person loses his first fright, one hundred feet or one thousand feet elevation makes little difference to him. It was this way with Miss Nestor.

Now, indeed, could Tom demonstrate to her some of the fine points of navigation in the upper currents, and though he did no risky "stunts," he showed the girl what it means to do an ascending spiral, how to cut corners, how to twist around in the figure eight, and do other things. Tom did not try for the great speed of which he knew his craft was capable, for he knew there was some risk with Miss Nestor aboard. But he did nearly everything else, and when he sent the Humming-Bird down he had made another convert and devotee to the royal sport of aeroplaning.

"Oh! I never would dared believe I could do it!" exclaimed the girl, as with flushed cheeks and dancing eyes she dismounted from the seat. "Mamma and papa will never believe I did it!"

"Bring them over, and I'll take them for a flight," said Tom, with a laugh, as Mary departed.

Tom received an answer to his letter to Mr. Sharp that night.

"Andy Foger's entry blank states," wrote the balloonist, "that he is constructing his aeroplane in the village of Hampton, which is about fifty miles from your place. If there is anything further I can do for you, Tom, let me know. I will see you at the meet. Hope you win the prize."

"In Hampton, eh?" mused Tom. "So that's where Andy has been keeping himself all this while. His uncle lives there, and that's the reason for it. He wanted to keep it a secret from me, so he could use my stolen plans for his craft. But he shan't do it! I'll go to Hampton!"

"And I'll go with you!" declared Mr. Damon, who was with Tom when he got the note from the balloonist. "We'll get to the bottom of this mystery after a while, Tom."

Delaying a few days, to make the final changes in his aeroplane, Tom and Mr. Damon departed for Hampton one morning. They thought first of going in the Butterfly, but as they wanted to keep their mission as secret as possible, they decided to go by train, and arrive in the town quietly and unostentatiously. They got to Hampton late that afternoon.

"What's the first thing to be done?" asked Mr. Damon as they walked up from the station, where they were almost the only persons who alighted from the train.

"Go to the hotel," decided Tom. "There's only one, I was told, so there's not much choice."

Hampton was a quiet little country town of about five thousand inhabitants, and Tom soon learned the address of Mr. Bentley, Andy's uncle, from the hotel clerk.

"What business is Mr. Bentley in?" asked Tom, for he wanted to learn all he could without inquiring of persons who might question his motives.

"Oh, he's retired," said the clerk. "He lives on the interest of his money. But of late he's been erecting some sort of a building on his back lot, like a big shed, and folks are sort of wondering what he's doing in it. Keeps mighty secret about it. He's got a young fellow helping him."

"Has he got red hair?" asked Tom, while his heart beat strangely fast.

"Who? Mr. Bentley? No. His hair's black."

"I mean the young fellow."

"Oh! his? Yes, his is red. He's a nephew, or some relation to Mr. Bentley. I did hear his name, but I've forgotten it. Sandy, or Andy, or some such name as that."

This was near enough for Tom and Mr. Damon, and they did not want to risk asking any more questions. They turned away to go to their rooms, as the clerk was busy answering inquiries from some other guests. A little later, supper was served, and Tom, having finished, whispered to Mr. Damon to join him upstairs as soon as he was through.

"What are you going to do?" asked the eccentric man.

"We're going out and have a look at this new shed by moonlight," decided Tom. "I want to see what it's like, and, if possible, I want to get a peep inside. I'll soon be able to tell whether or not Andy is using my stolen plans."

"All right. I'm with you. Bless my bill of fare! But we seem to be doing a lot of mysterious work of late."

"Yes," agreed Tom. "But if you have to bless anything to-night, Mr. Damon, please whisper it. Andy, or some of his friends, may be about the shed, and as soon as they hear one of your blessings they'll know who's coming."

"Oh, I'll be careful," promised Mr. Damon.

"Andy will find out, sooner or later, that we are in town," went on Tom, "but we may be able to learn to-night what we want to know, and then we can tell how to act."

A little later, as if they were merely strolling about, Mr. Damon and Tom headed for Mr. Bentley's place, which was on the outskirts of the town. There was a full moon, and the night was just right for the kind of observation Tom wanted to make. There were few persons abroad, and the young inventor thought he would have no one spying on him.

They located the big house of Andy's uncle without trouble. Going down a side street, they had a glimpse of a shed, built of new boards, standing in the middle of a large lot. About the structure was a new, high wooden fence, but as Tom and his friend passed along it they saw that a gate in it was open.

"I'm going in!" whispered Tom.

"Will it be safe?" asked Mr. Damon.

"I don't care whether it will be or not. I've got to know what Andy is doing. Come on! We'll take a chance!"

Cautiously they entered the enclosure. The big shed was dark, and stood out conspicuously in the moonlight.

"There doesn't seem to be any one here," whispered Tom. "I wonder if we could get a look in the window?"

"It's worth trying, anyhow," agreed Mr. Damon. "I'm with you, Tom."

They drew nearer to the shed. Suddenly Tom stepped on a stick, which broke with a sharp report.

"Bless my spectacles!" cried Mr. Damon, half aloud.

There was silence for a moment, and then a voice cried out:

"Who's there? Hold on! Don't come any farther! It's dangerous!"

Tom and Mr. Damon stood still, and from behind the shed stepped Andy Foger and a man.

"Oh! it's you, is it, Tom Swift?" exclaimed the red-haired bully. "I thought you'd come sneaking around. Come on, Jake! We'll make them wish they'd stayed home!" And Andy made a rush for Tom.



Chapter Fourteen

The Great Test

"Bless my gizzard!" exclaimed Mr. Damon, who hardly knew what to do. "We'd better be getting out of here, Tom!"

"Not much!" exclaimed the young inventor. "I never ran from Andy Foger yet, and I'm not going to begin now."

He assumed an attitude of defense, and stood calmly awaiting the onslaught of the bully; but Andy knew better than to come to a personal argument with Tom, and so the red-haired lad halted some paces off. The man, who had followed young Foger, also stopped.

"What do you want around here, Tom Swift?" demanded Andy.

"You know very well what I want," said the young inventor, calmly. "I want to know what you did with the aeroplane plans you took from my house."

"I never took any!" declared Andy vigorously

"Well, there's no use discussing that," went on Tom. "What I came here to find out, and I don't mind telling you, is whether or not you are building a monoplane to compete against me, and building it on a model invented by me; and what's more, Andy Foger, I intend to find this out, too!"

Tom started toward the big shed, which loomed up in the moonlight.

"Stand back!" cried Andy, getting in Tom's way. "I can build any kind of an aeroplane I like, and you can't stop me!"

"We'll see about that," declared the young inventor, as he kept on. "I'm not going to allow my plans to be stolen, and a monoplane made after them, and do nothing about it."

"You keep away!" snarled Andy, and he grabbed Tom by the shoulder and struck him a blow in the chest. He must have been very much excited, or otherwise he never would have come to hostilities this way with Tom, whom he well knew could easily beat him.

The blow, together with the many things he had suffered at Andy's hands, was too much for our hero. He drew back his fist, and a moment later Andy Foger was stretched out on the grass. He lay there for a moment, and then rose up slowly to his knees, his face distorted with rage.

"You—you hit me!" he snarled.

"Not until you hit first," said Tom calmly.

"Bless my punching bag! That's so!" exclaimed Mr. Damon.

"You'll suffer for this!" whined Andy, getting to his feet, but taking care to retreat from Tom, who stood ready for him. "I'll get square with you for this! Jake, come on, and we'll get our guns!"

Andy turned and hurried back toward the shed, followed by the evil-looking man, who had apparently been undecided whether to attack Mr. Damon or Tom. Now the bully and his companion were in full retreat.

"We'll get our guns, and then we'll see whether they'll want to stay where they're not wanted!" went on Andy, threateningly.

"Bless my powderhorn! What had we better do?" asked Mr. Damon.

"I guess we'd better go back," said Tom calmly. "Not that I'm afraid of Andy. His talk about guns is all bluff; but I don't want to get into any more of a row, and he is just ugly and reckless enough to make trouble. I'm afraid we can't learn what we came to find out, though I'm more convinced than ever that Andy is using my plans to make his aeroplane."

"But what can you do?"

"I'll see Mr. Sharp, and send a protest to the aviation committee. I'll refuse to enter if Andy flies in a model of my Humming-Bird, and I'll try to prevent him from using it after he gets it on the ground. That is all I can do, it seems, lacking positive information. Come on, Mr. Damon. Let's get back to our hotel, and we'll start for home in the morning."

"I have a plan," whispered the odd man.

"What is it?" asked Tom, narrowly watching for the reappearance of Andy and the man.

"I'll stay here until they come, then I'll pretend to run away. They'll chase after me, and get all excited, and you can go up and look in the shed windows. Then you can join me later. How's that?"

"Too risky. They might fire at you by mistake. No. We'll both go. I've found out more than enough to confirm my suspicions."

They turned out of the lot which contained the shed, and walked toward the road, just as Andy and his crony came back.

"Huh! You'd better go!" taunted the bully.

Tom had a bitter feeling in his heart. It seemed as if he was defeated, and he did not like to retreat before Andy.

"You'd better not come back here again, either," went on Andy.

Tom and Mr. Damon did not reply, but kept on in silence. They returned to Shopton the next day.

"Well," remarked Tom, when he had gone out to look at his Humming-Bird, "I know one thing. Andy Foger may build a machine something like this, but I don't believe he can put in all the improvements I have, and certainly he can't equal that engine; eh, dad?"

"I hope not, Tom," replied his father, who seemed to be much improved in health.

"When are you going to try for speed?" asked Mr. Damon.

"To-morrow, if I can get it tuned up enough," replied Tom, "and I think I can. Yes, we'll have the great test to-morrow, and then I'll know whether I really have a chance for that ten thousand dollars."

Never before had Tom been so exacting in his requirements of his air craft as when, the next day, the Humming-Bird was wheeled out to the flight ground, and gotten ready for the test. The young inventor went over every bolt, brace, stay, guy wire and upright. He examined every square inch of the wings, the tips, planes and rudders. The levers, the steering wheel, the automatic equilibrium attachments and the balancing weights were looked at again and again.

As for the engine, had it been a delicate watch, Tom could not have scrutinized each valve, wheel, cam and spur gear more carefully. Then the gasoline tank was filled, the magneto was looked after, the oil reservoirs were cleaned out and freshly filled, and finally the lad remarked:

"Well, I guess I'm ready. Come along, Mr. Damon."

"Am I going with you in the test?"

"Surely. I've been counting on you. If you're to be with me in the race, you want to get a sample of what we can do. Take your place. Mr. Jackson, are you ready to time us?"

"All ready, Tom."

"And, dad, do you feel well enough to check back Mr. Jackson's results? I don't want any errors."

"Oh, yes, Tom. I can do it."

"Very well, then. Now this is my plan. I'm going to mount upward on an easy slant, and put her through a few stunts first, to warm up, and see that everything is all right. Then, when I give the signal, by dropping this small white ball, that means I'm ready for you to start to time me. Then I'll begin to try for the record. I'll go about the course in a big ellipse, and—well, we'll see what happens."

While Mr. Damon was in his seat the young inventor started the propeller, and noted the thrust developed. It was satisfactory, as measured on the scale, and then Tom took his place.

"Let her go!" he cried to Mr. Jackson and Eradicate, after he had listened to the song of the motor for a moment. The Humming-Bird flew across the course, and a moment later mounted into the air.

Tom quickly took her up to about two thousand feet, and there, finding the conditions to his liking, he began a few evolutions designed to severely test the craft's stability, and to learn whether the engine was working properly.

"How about it?" asked Mr. Damon anxiously.

"All right!" shouted Tom in his ear, for the motor was making a great racket. "I guess we'll make the trial next time we come around. Get ready to drop the signal ball."

Tom slowly brought the aeroplane around in a graceful curve. He sighted down, and saw the first tall white pole that marked the beginning of the course.

"Drop!" he called to Mr. Damon.

The white rubber ball went to the earth like a shot. Mr. Jackson and Mr. Swift saw it, and started their timing-watches. Tom opened the throttle and advanced the spark. The great test was on!

The Humming-Bird trembled and throbbed with the awful speed of the motor, like a thing alive. She seemed to rush forward as an eagle dropping down from a dizzy height upon some hapless prey.

"Faster yet!" murmured Tom. "We must go faster yet!"

The motor was warming up. Streaks of fire came from it. The exhaust of the explosions was a continuous roar. Faster and faster flew the frail craft.

Around and around the air course she circled. The wind appeared to be rushing beneath the planes and rudders with the velocity of a hurricane. Had it not been for the face protectors they wore, Tom and Mr. Damon could not have breathed. For ten minutes this fearful speed was kept up. Then Tom, knowing he had run the motor to the limit, slowed it down. Next he shut it off completely, and prepared to volplane back to earth. The silence after the terrific racket was almost startling. For a moment neither of the aviators spoke. Then Mr. Damon said:

"Do you think you did it, Tom?"

"I don't know. We'll soon find out. They'll have the record." And he motioned toward the earth, which they were rapidly nearing.



Chapter Fifteen

A Noise in the Night

"Well, did I make it? Make any kind of a record?" asked Tom eagerly, as he brought the trim little craft to a stop, after it had rolled along the ground on the bicycle wheels.

"What do you think you did?" asked Mr. Jackson, who had been busy figuring on a slip of paper.

"Did I get her up to ninety miles an hour?" inquired Tom eagerly. "If I did, I know when the motor wears down a bit smoother that I can make her hit a hundred in the race, easily. Did I touch ninety, Mr. Jackson?"

"Better than that, Tom! Better than that!" cried his father.

"Yes," joined in Mr. Jackson. "Allowing for the difference in our watches, Tom, your father and I figure that you did the course at the rate of one hundred and twelve miles an hour!"

"One hundred and twelve!" gasped the young inventor, hardly able to believe it.

"I made it a hundred and fifteen," said Mr. Swift, who was almost as pleased as was his son, "and Mr. Jackson made it one hundred and eleven; so we split the difference, so to speak. You certainly have a sky racer, Tom, my boy!"

"And I'll need it, too, dad, if I'm to compete with Andy Foger, who may have a machine almost like mine."

"But I thought you were going to object to him if he has," said Mr. Damon, who had hardly recovered from the speedy flight through space.

"Well, I was just providing for a contingency, in case my protest was overruled," remarked Tom. "But I'm glad the Humming-Bird did so well on her first trial. I know she'll do better the more I run her. Now we'll get her back in her 'nest,' and I'll look her over, when she cools down, and see if anything has worked loose."

But the trim little craft needed only slight adjustments after her tryout, for Tom had built her to stand up under a terrific strain.

"We'll soon be in shape for the big race," he announced, "and when I bring home that ten thousand dollars I'm going to abandon this sky-scraping business, except for occasional trips."

"What will you do to occupy your mind?" asked Mr. Damon.

"Oh, I'm going to travel," announced Tom. "Then there's my new electric rifle, which I have not perfected yet. I'll work on that after I win the big race."

For several days after the first real trial of his sky racer Tom was busy going over the Humming-Bird, making slight changes here and there. He was the sort of a lad who was satisfied with nothing short of the best, and though neither his father nor Mr. Jackson could see where there was room for improvement, Tom was so exacting that he sat up for several nights to perfect such little details as a better grip for the steering-lever, a quicker way of making the automatic equilibriumizer take its position, or an improved transmitter for the wireless apparatus.

That was a part of his monoplane of which Tom was justly proud, for though many aeroplanes to-day are equipped with the sending device, few can receive wireless messages in mid-air. But Tom had seen the advantage of this while making a trip in the ill-fated Red Cloud to the cave of the diamond makers, and he determined to have his new craft thus provided against emergencies. The wireless outfit of the Humming-Bird was a marvel of compactness.

Thus the days passed, with Tom very busy; so busy, in fact, that he hardly had time to call on Miss Nestor. As for Andy Foger, he heard no more from him, and the bully was not seen around Shopton. Tom concluded that he was at his uncle's place, working on his racing craft.

The young inventor sent a formal protest to the aviation committee, to be used in the event of Andy entering a craft which infringed on the Humming-Bird, and received word from Mr. Sharp that the interests of the young inventor would be protected. This satisfied Tom.

Still, at times, he could not help wondering how the first plans had so mysteriously disappeared, and he would have given a good deal to know just how Andy got possession of them, and how he knew enough to use them.

"He, or some one whom he hired, must have gotten into our house mighty quickly that day," mused Tom, "and then skipped out while dad fell into a little doze. It was a mighty queer thing, but it's lucky it was no worse."

The time was approaching for the big aviation meet. Tom's craft was in readiness, and had been given several other trials, developing more speed each time. Additional locks were put on the doors of the shed, and more burglar-alarm wires were strung, so that it was almost a physical impossibility to get into the Humming-Bird's "nest" without arousing some one in the Swift household.

"And if they do, I guess we'll be ready for them," said Tom grimly. He had been unable to find out who it was that had attempted once before to damage the monoplane, but he suspected it was the ill-favored man who was working with Andy.

As for Mr. Swift, at times he seemed quite well, and again he required the services of a physician.

"You will have to be very careful of your father, Tom," said Dr. Gladby. "Any sudden shock or excitement may aggravate his malady, and in that case a serious operation will be necessary."

"Oh, we'll take good care of him," said the lad; but he could not help worrying, though he tried not to let his father see the strain which he was under.

It was some days after this, and lacking about a week until the meet was to open, when a peculiar thing happened. Tom had given his Humming-Bird a tryout one day, and had then begun to make arrangements for taking it apart and shipping it to Eagle Park. For he would not fly to the meet in it, for fear of some accident. So big cases had been provided.

"I'll take it apart in the morning," decided Tom, as he went to his room, after seeing to the burglar alarm, "and ship her off. Then Mr. Damon and I will go there, set her up, and get ready to win the race."

Tom had opened all the windows in his room, for it was very warm. In fact it was so warm that sleep was almost out of the question, and he got up to sit near the windows in the hope of feeling a breeze.

There it was more comfortable, and he was just dozing off, and beginning to think of getting back into bed, when he was aware of a peculiar sound in the air overhead.

"I wonder if that's a heavy wind starting up?" he mused. "Good luck, if it is! We need it." The noise increased, sounding more and more like wind, but Tom, looking out into the night, saw the leaves of the trees barely moving.

"If that's a breeze, it's taking its own time getting here," he went on.

The sound came nearer, and then Tom knew that it was not the noise of the wind in the trees. It was more like a roaring and rumbling.

"Can it be distant thunder?" Tom asked himself. "There is no sign of a storm." Once more he looked from the window. The night was calm and clear—the trees as still as if they were painted.

The sound was even more plain now, and Tom, who had sharp ears, at once decided that it was just over the house—directly overhead. An instant later he knew what it was.

"The motor of an aeroplane, or a dirigible balloon!" he exclaimed. "Some one is flying overhead!"

For an instant he feared lest the shed had been broken into, and his Humming-Bird taken, but a glance toward the place seemed to show that it was all right.

Then Tom hastily made his way to where a flight of stairs led to a little enclosed observatory on the roof.

"I'm going to see what sort of a craft it is making that noise," he said.

As he opened the trap door, and stepped out into the little observatory the sound was so plain as to startle him. He looked up quickly, and, directly overhead he saw a curious sight.

For, flying so low as to almost brush the lightning rod on the chimney of the Swift home, was a small aeroplane, and, as Tom looked up, he saw in a light that gleamed from it, two figures looking down on him.



Chapter Sixteen

A Mysterious Fire

For a few moments Tom did not know what to think. Not that the sight of aeroplanes in flight were any novelty to him, but to see one flying over his house in the dead of night was a little out of the ordinary. Then, as he realized that night-flights were becoming more common, Tom tried to make out the details of the craft.

"I wish I had brought the night glasses with me," he said aloud.

"Here they are," spoke a voice at his side, and so suddenly that Tom was startled. He looked down, and saw Mr. Jackson standing beside him.

"Did you hear the noise, too?" the lad asked the engineer.

"Yes. It woke me up. Then I heard you moving around, and I heard you come up here. I thought maybe it was a flight of meteors you'd come to see, and I knew the glasses would be handy, so I stopped for them. Take a look, Tom. It's an aeroplane; isn't it?"

"Yes, and not moving very fast, either. They seem to be circling around here."

The young inventor was peering through the binoculars, and, as soon as he had the mysterious craft in focus, he cried:

"Look, Mr. Jackson, it's a new kind of monoplane. I never saw one like it before. I wonder who could have invented that? It's something like a Santos-Dumont and a Bleriot, with some features of Cornu's Helicopter. That's a queer machine."

"It certainly is," agreed the engineer, who was now sighting through the glasses. In spite of the darkness the binoculars brought out the peculiarities of the aeroplane with considerable distinctness.

"Can you make out who are in it?" asked Tom.

"No," answered Mr. Jackson. "You try."

But Tom had no better luck. There were two persons in the odd machine, which was slowly flying along, moving in a great circle, with the Swift house for its center.

"I wonder why they're hanging around here?" asked Tom, suspiciously.

"Perhaps they want to talk to you," suggested Mr. Jackson. "They may be fellow inventor—perhaps one of them is that Philadelphia man who had the Whizzer."

"No," replied the lad. "He would have sent me word if he intended calling on me. Those are strangers, I think. There they are, coming back again."

The mysterious aeroplane was once more circling toward the watchers on the roof. There was a movement on the steps, near which Tom was standing, and his father came up.

"Is anything the matter?" he asked anxiously.

"Only a queer craft circling around up here," was the reply. "Come and see, dad."

Mr. Swift ascended to the roof. The aeroplane was higher now, and those in her could not so easily be made out. Tom felt a vague sense of fear, as though he was being watched by the evil eyes of his enemies. More than once he looked over to the shed where his craft was housed, as though some danger might threaten it. But the shed of the Humming-Bird showed no signs of invaders.

Suddenly the mysterious aeroplane increased its speed. It circled about more quickly, and shot upward, as though to show the watchers of what it was capable. Then, with a quick swoop it darted downward, straight for the building where Tom's newest invention was housed.

"Look out! They'll hit something!" cried the young inventor, as though those in the aeroplane could hear him.

Then, just as though they had heeded his warning, the pilots of the mysterious craft shot her upward, after she had hovered for an instant over the big shed.

"That was a queer move," said Tom. "It looked as if they lost control of her for a moment."

"And they dropped something!" cried Mr. Jackson. "Look! something fell from the aeroplane on the roof of the shed."

"Some tool, likely," spoke Tom. "I'll get it in the morning, and see what sort of instruments they carry. I'd like to examine that machine, though."

The queer aeroplane was now shooting off in the darkness and Tom followed it with the glasses, wondering what its construction could be like. He was to have another sight of it sooner than he expected.

"Well, we may as well get back to bed," said Mr. Jackson. "I'm tired, and we've got lots to do to-morrow."

"Yes," agreed Tom. "It's cooler now. Come on, dad."

Tom fell into a light doze. He thought afterward he could not have slept more than half an hour when he heard a commotion out in the yard. For an instant he could not tell what it was, and then, as he grew wider awake he knew that it was the shouting of Eradicate Sampson, and the braying of Boomerang.

But what was Eradicate shouting?

"Fire! Fire! Fire!"

Tom leaped to his window.

"Wake up, Massa Tom! Wake up! De areoplane shed am on fire, an' de Humming-Bird will burn up! Hurry! Hurry!"

Tom looked out. Flames were shooting up from the roof of the shed where his precious craft was kept.



Chapter Seventeen

Mr. Swift is Worse

Almost before the echoes of Eradicate's direful warning cry had died away, Tom was on his way out of the house, pausing only long enough to slip on a pair of shoes and his trousers. There was but one thought in his mind. If he could get the Humming-Bird safely out he would not care if the shed did burn, even though it contained many valuable tools and appliances.

"We must save my new aeroplane!" thought Tom, desperately. "I've got to save her!"

As he raced through the hall he caught up a portable chemical fire-extinguisher. Tom saw his father's door open, and Mr. Swift looked out.

"What is it?" he called anxiously.

"Fire!" answered the young inventor, almost before he thought of the doctor's warning that Mr. Swift must not be excited. Tom wished he could recall the word, but it was too late. Besides Eradicate, down in the yard was shouting at the top of his voice:

"Fire! Fire! Fire!"

"Where, Tom?" gasped Mr. Swift, and his son thought the aged inventor grew suddenly paler.

"Aeroplane shed," answered the lad. "But don't worry dad. It's only a small blaze. We'll get it out. You stay here. We'll attend to it—Mr. Jackson and Eradicate and I."

"No—I'm going to help!" exclaimed Mr. Swift, sturdily. "I'll be with you, Tom. Go on!"

The lad rushed down to the yard, closely followed by the engineer, who had caught up another extinguisher. Eradicate was rushing about, not knowing what to do, but still keeping up his shouting.

"It's on de roof! De roof am all blazin'!" he yelled.

"Quit your noise, and get to work!" cried Tom. "Get out a ladder, Rad, and raise it to the side of the shed. Then play this extinguisher on the blaze. Mr. Jackson, you help me run the Humming-Bird out. After she's safe we'll tackle the fire."

Tom cast a hurried look at the burning shed. The flames were shooting high up from the roof, now, and eating their way down. As he rushed toward the big doors, which he intended to open to enable him to run out his sky racer, he was wondering how the fire came to start so high up as the roof. He wondered if a meteor could have fallen and caused it.

As the doors, which were quickly unlocked by Tom, swung back, and as he and the engineer started to go in, they were met by choking fumes as if of some gas. They recoiled for the moment.

"What—what's that?" gasped Tom, coughing and sneezing.

"Some chemical—I—I don't know what kind," spluttered Mr. Jackson. "Have you any carboys of acid in there Tom, that might have exploded by the heat?"

"No; not a thing. Let's try again."

Once more they tried to go in, but were again driven back by the distressing fumes. The fire was eating down, now. There was a hole burned in the roof, and by the leaping tongues of flame Tom could see his aeroplane. It was almost in the path of the blaze.

"We must get her out!" he shouted. "I'm going in!"

But it was impossible, and the daring young inventor nearly succumbed to the choking odors. Mr. Jackson dragged him back.

"We can't go in!" he cried. "There has been some mysterious work here! Those fumes were put here to keep us from saving the machine. This fire has been set by some enemy! We can't go in!"

"But I am going!" declared Tom. "We'll try the back door."

They rushed to that, but again were driven out by the gases and vapors, which were mingled with the smoke. Disheartened, yet with a wild desire to do something to save his precious craft, Tom Swift drew back for a moment.

As he did so he heard a hiss, as Eradicate turned the chemical stream on the blaze. Tom looked up. The faithful colored man was on a ladder near the burning roof, acting well his part as a fireman.

"That's the stuff!" cried Tom. "Come on, Mr. Jackson. Maybe if we use the chemical extinguishers we can drive out those fumes!"

The engineer understood. He took up the extinguisher he had brought, and Tom got a second one from a nearby shed. Then Mr. Swift came out bearing another.

"You shouldn't have come, dad! We can attend to it!" cried Tom, fearing for the effect of the excitement on his invalid parent.

"Oh, I couldn't stay there and see the shed burn. Are you getting it under control? Why don't you run out the Humming-Bird?"

Tom did not mention the choking fumes. He passed up a full extinguisher to Eradicate, who had used all the chemical in his. Then Tom got another ladder, and soon three streams were being directed on the flames. They had eaten, a pretty big hole in the roof, but the chemicals were slowly telling on them.

As soon as he saw that Eradicate and Mr. Jackson could control the blaze, Tom descended to the ground, and ran once more to the big doors. He was determined to make another try to wheel out the aeroplane, for he saw from above that the flames were now on the side wall, and might reach the craft any minute. And it would not take much to inflict serious damage on the sky racer.

"I'll get her, fumes or no fumes!" murmured Tom, grimly. And, whether it was the effect of the chemical streams, or whether the choking odors were dissipated through the hole in the roof was not manifested, but, at any rate, Tom found that he could go in, though he coughed and gasped for breath.

He wheeled the aeroplane outside, for the Humming-Bird was almost as light as her namesake. A hurried glance by the gleam of the dying fire assured Tom that his craft was not damaged beyond a slight scorching of one of the wing tips.

"That was a narrow escape!" he murmured, as he wheeled the sky racer far away, out of any danger from sparks. Then he went back to help fight the fire, which was extinguished in about ten minutes more.

"It was a mighty queer blaze," said Mr. Jackson, "starting at the top that way. I wonder what caused it?"

"We'll investigate in the morning," decided Tom. "Now, dad, you must get back to your room." He turned to help his father in, but at that moment Mr. Swift, who was trying to say something, fell over in a dead faint.

"Quick! Help me carry him into the house!" cried Tom. "Then telephone for Dr. Gladby, Mr. Jackson."

The physician looked grave when, half an hour later, he examined his patient.

"Mr. Swift is very much worse," he said in a low voice. "The excitement of the fire has aggravated his ailment. I would like another doctor to see him, Tom."

"Another doctor?" Tom's voice showed his alarm.

"Yes, we must have a consultation. I think Dr. Kurtz will be a good one to call in. I should like his opinion before I decide what course to take."

"I'll send Eradicate for him at once," said the young inventor, and he went to give the colored man his instructions, while his heart was filled with a great fear for his father.



Chapter Eighteen

The Broken Bridge

Dr. Kurtz looked as grave as did Dr. Gladby when he had made an examination of the patient. Mr. Swift was still in a semi-conscious condition, hardly breathing as he rested on the bed where they had placed him after the fire.

"Vell," said the German physician, after a long silence, "vot is your obinion, my dear Gladby?"

"I think an operation is necessary."

"Yes, dot is so; but you know vot kind of an operation alone vill safe him; eh, my dear Gladby?"

Dr. Gladby nodded.

"It will be a rare and delicate one," he said. "There is but one surgeon I know of who can do it."

"You mean Herr Hendrix?" asked Dr. Kurtz.

"Yes, Dr. Edward Hendrix, of Kirkville. If he can be induced to come I think there is a chance of saving Mr. Swift's life. I'll speak to Tom about it."

The two physicians, who had been consulting together, summoned the youth from another room, where, with Mrs. Baggert and Mr. Jackson he had been anxiously awaiting the verdict.

"What is it?" the young inventor asked Dr. Gladby.

The medical man told him to what conclusion he and his colleague had arrived, adding:

"We advise that Dr. Hendrix be sent for at once. But I need hardly tell you, Tom, that he is a noted specialist, and his services are in great demand. He is hard to get."

"I'll pay him any sum he asks!" burst out the youth. "I'll spend all my fortune—and I have made considerable money of late—I'll spend every cent to get my father well! Money need not stand in the way, Dr. Gladby."

"I knew that, Tom. Still Dr. Hendrix is a very busy man, and it is hard to induce him to come a long distance. It is over a hundred miles to Kirkville, and it is an out-of-the-way place. I never could understand why Dr. Hendrix settled there. But there he is, and if we want him he will have to come from there. The worst of it is that there are few trains, and only a single railroad line from there to Shopton."

"Then I'll telegraph," decided Tom. "I'll offer him his own price, and ask him to rush here as soon as he can."

"You had better let Dr. Kurtz and me attend to that part of it," suggested the physician. "Dr. Hendrix would hardly come on the request of some one whom he did not know. I'll prepare a telegram, briefly explaining the case. It is the sort of an operation Dr. Hendrix is much interested in, and I think he will come on that account, if for no other reason. I'll write out the message, and you can have Eradicate take it to the telegraph office."

"I'll take it myself!" exclaimed Tom, as he got ready to go out into the night with the urgent request. "Is there any immediate danger for my father?" he asked.

"No; not any immediate danger," replied Dr. Gladby. "But the operation is imperative if he is to live. It is his one and only chance."

Tom thought only of his father as he hurried on through the night. Even the prospect of the great race, so soon to take place, had no part in his mind.

"I'll not race until I'm sure dad is going to get better," he decided. With the message to the noted specialist Tom also sent one to Mr. Damon, telling him the news, and asking him to come to Shopton. Tom felt that the presence of the odd gentleman would help him, and Mr. Damon, who first intended to stay on at the Swift home until he and Tom departed for Eagle Park, had gone back to his own residence to attend to some business Tom knew he would come in the morning, and Mr. Damon did arrive on the first train.

"Bless my soul!" he exclaimed with ready sympathy, as he extended his hand to Tom. "What's all this?" The young inventor told him, beginning with the fire that had been the cause of the excitement which produced the change in Mr. Swift.

"But I have great hopes that the specialist will be able to cure him," said Tom, for, with the coming of daylight, his courage had returned to him. "Dr. Gladby and Dr. Kurtz depend a great deal on Dr. Hendrix," he said.

"Yes, he certainly is a wonderful man. I have heard a great deal about him. I have no doubt but what he will cure your father. But about the fire? How did it start?"

"I don't know, but now that I have a few hours to spare before the doctor can get here, I'm going to make an examination."

"Bless my penwiper, but I'll help you."

Tom went into the house, to inquire of Mrs. Baggert, for probably the tenth time that morning, how his father was doing. Mr. Swift was still in a semi-conscious condition, but he recognized Tom, when the youth stood at his bedside.

"Don't worry about me, son," said the brave old inventor, as he took Tom's hand. "I'll be all right. Go ahead and get ready for the race. I want you to win!"

Tears came into Tom's eyes. Would his father be well enough to allow him to take part in the big event? He feared not.

By daylight it was seen that quite a hole had been burned in the aeroplane shed. Tom and Mr. Damon, accompanied by Mr. Jackson, walked through the place.

"And you say the fire broke out right after you had seen the mysterious airship hovering over the house?" asked the eccentric man.

"Well, not exactly after," answered Tom, "but within an hour or so. Why do you ask?"

But Mr. Damon did not answer. Something on the floor of the shed, amid a pile of blackened and charred pieces of wood, attracted his attention. He stooped over and picked it up.

"Is this yours?" he asked Tom.

"No. What is it?"

The object looked like a small iron ball, with a tube about half an inch in diameter projecting slightly from it. Tom took it'.

"Why, it looks like an infernal machine or a dynamite bomb," he said. "I wonder where it came from? Guess I'd better drop it in a pail of water. Maybe Eradicate found it and brought it here. I never saw it before. Mr. Jackson, please hand me that pail of water. We'll soak this bomb."

"There is no need," said Mr. Damon, quietly. "It is harmless now. It has done its work. It was that which set fire to your shed, and which caused the stifling fumes."

"That?" cried Tom.

"Yes. This ball is hollow, and was filled with a chemical. It was dropped on the roof, and, after a certain time, the plug in the tube was eaten through, the chemicals ran out, set the roof ablaze, and, dripping down inside spread the choking odors that nearly prevented you from getting out your aeroplane."

"Are you sure of this?" asked the young inventor.

"Positive. I read about these bombs recently. A German invented them to be used in attacking a besieged city in case of war."

"But how did this one get on my shed roof?" asked Tom.

"It was dropped there by the mysterious airship!" exclaimed the odd man. "That was why the aeroplane moved about over your place. Those in it hoped that the fire would not break out until you were all asleep, and that the shed and the Humming-Bird would be destroyed before you came to the rescue. Some of your enemies are still after you, Tom."

"And it was Andy Foger, I'll wager!" he cried. "He was in that aircraft! Oh, I'll have a long score to settle with him!"

"Of course you can't be sure it was he," said Mr. Damon, "but I wouldn't be a bit surprised but what it was. Andy is capable of such a thing. He wanted to prevent you from taking part in the race."

"Well, he sha'n't!" cried Tom, and then he thought of his invalid father. They made a further examination of the shed, and discovered another empty bomb. Then Tom recalled having seen something drop from the mysterious aeroplane as it passed over the shed.

"It was these bombs," he said. "We certainly had a narrow escape! Oh, wait until I settle my score with Andy Foger!"

As there would be but little use for the aeroplane shed now, if Tom sent his craft off to the meet, it was decided to repair it temporarily only, until he returned.

Accordingly, a big tarpaulin was fastened over the hole in the roof. Then Tom put a new wing tip on in place of the one that had been scorched. He looked all over his sky racer, and decided that it was in fit condition for the coming meet.

"I'll begin to take it apart for shipment, as soon as I hear from the specialist that dad is well enough for me to go," he said.

It was a few hours after the discovery of the empty bomb that Tom saw Dr. Gladby coming along. The physician was urging his horse to top speed. Tom felt a vague fear in his heart.

"I've got a message from Dr. Hendrix, Tom," he said, as he stopped his carriage, and approached the lad.

"When can he come?" asked the young inventor, eagerly.

"He can't get here, Tom."

"Can't get here! Why not?"

"Because the railroad bridge has collapsed, and there is no way to come. He can't make any other connections to get here in time—in time to do your father any good, Tom. He has just sent me a telegram to that effect. Dr. Hendrix can't get here, and..." Dr. Gladby paused.

"Do you mean that my father may die if the operation is not performed?" asked Tom, in a low voice.

"Yes," was the answer.

"But can't Dr. Hendrix drive here in an auto?" asked the lad. "Surely there must be some way of getting over the river, even if the railroad bridge is down. Can't he cross in a boat and drive here?"

"He wouldn't be in time, Tom. Don't you understand, Dr. Hendrix must be here within four hours, if he is to save your father's life. He never could do it by driving or by coming on some other road, or in an auto. He can't make the proper connections. There is no way."

"Yes, there is!" cried Tom, suddenly. "I know a way!"

"How?" asked Dr. Gladby, thrilled by Tom's ringing tones. "How can you do it, Tom?"

"I'll go for Dr. Hendrix in my Humming-Bird."

"Going for him would do no good. He must be brought here."

"And so he shall be!" cried Tom. "I'll bring him here in my sky racer—if he has the nerve to stand the journey, and I think he has! I'll bring Dr. Hendrix here!" and Tom hurried away to prepare for the thrilling trip.



Chapter Nineteen

A Nervy Specialist

There was little time to lose. Every moment of delay meant so much less chance for the recovery of Mr. Swift. Even now the periods of consciousness were becoming shorter and farther apart. He seemed to be sinking.

Tom resolutely refused to think of the possibility of death, as he went in to bid his parent good-by before starting off on his trip through the air. Mr. Swift barely knew his son, and, with tears in his eyes, though he bravely tried to keep them back, the young inventor went out into the yard.

There stood the Humming-Bird, with Mr. Jackson, Mr. Damon and Eradicate working over her, to get her in perfect trim for the race before her—a race with death.

Fortunately there was little to be done to get the speedy craft ready. Tom had accomplished most of what was necessary, while waiting for word from Dr. Hendrix. Now about all that needed to be done was to see that there was plenty of gasoline and oil in the reservoirs.

"I'll give you a note to Dr. Hendrix," said Mr. Gladby, as Tom was fastening on his faceguard. "I—I trust you won't be disappointed, Tom. I hope he will consent to return with you."

"He's got to come," said the young inventor, simply, as if that was all there was to it.

"Do you think you can make the trip in time?" asked Mr. Damon. "It is a little less than a hundred miles in an airline, but you have to go and go back. Can the aeroplane do it?"

"I'd be ashamed of her if she couldn't," said Tom, with a grim tightening of his lips. "She's just got to do it; that's all! But I know she will," and he patted the big propeller and the motor's shining cylinders as though the machine was a thing alive, like a horse or a dog, who could understand him.

He climbed to his seat, the other one holding a bag of sand to maintain a good balance.

"Start her," ordered Tom, and Mr. Jackson twisted the propeller. The motor caught at once, and the air throbbed with the noise of the explosions. Tom listened to the tune of the machinery. It sang true.

"Two thousand pounds thrust!" called the engineer, as he looked at the scale.

"Let her go!" cried Tom, whose voice was hardly heard above the roar. The trim little aeroplane scudded over the ground, gathering speed at every revolution of the wheels. Then with a spring like that of some great bird launching itself in flight, she left the earth, and took to the air. Tom was off on his trip.

Those left behind sent up a cautious cheer, for they did not want to disturb Mr. Swift. They waved their hands to the young inventor, and he waved his in reply. Then he settled down for one of the swiftest flights he had ever undertaken.

Tom ascended until he struck a favorable current of air. There was a little wind blowing in the direction he wished to take, and that aided him. But even against a powerful head-wind the Humming-Bird could make progress.

The young inventor saw the ground slipping backward beneath him. Carefully he watched the various indicators, and listened intently to the sound of the cylinders' explosions. They came rapidly and regularly. The motor was working well.

Tom glanced at the barograph. It registered two thousand feet, and he decided to keep at about that height, as it gave him a good view, and he could see to steer, for a route had been hastily mapped out for him by his friends.

Over cities, towns, villages, scattered farmhouses; across stretches of forest; over rivers, above big stretches of open country he flew. Often he could see eager crowds below, gazing up at him. But he paid no heed. He was looking for a sight of a certain broad river, which was near Kirkville. Then he knew he would be close to his goal.

He had speeded up the motor to the limit, and there was nothing to do now, save to manage the planes, wing tips and rudders, and to see that the gasoline and oil were properly fed to the machine.

Faster and faster went the Humming-Bird, but Tom's thoughts were even faster. He was thinking of many things—of his father—of what he would do if Mr. Swift died—of the mysterious airship—of the stolen plans—of the fire in the shed—of the great race—and of Andy Foger.

He took little note of time, and when, in less than an hour he sighted the river that told him he was near to Kirkville, he was rather startled.

"You certainly did come right along, Humming-Bird!" he murmured proudly.

He descended several hundred feet, and, as he passed over the town, the people of which grew wildly excited, he looked about for the house of the noted specialist. He knew how to pick it out, for Dr. Gladby had described it to him, and Tom was glad to see, as he came within view of the residence, that it was surrounded by a large yard.

"I can land almost at his door," he said, and he did, volplaning to earth with an ease born of long practice.

To say that Dr. Hendrix was astonished when Tom dropped in on him in this manner, would not be exactly true. The specialist was not in the habit of receiving calls from youths in aeroplanes, but the fact was, that Dr. Hendrix was so absorbed in his work, and thought so constantly about it, that it took a great deal to startle him out of his usual calm.

"And so you came for me in your aeroplane?" he asked of Tom, as he gazed at the trim little craft. It is doubtful if he really saw it, however, as Dr. Hendrix was just then thinking of an operation he had performed a few hours before. "I'm sorry you had your trip for nothing," he went on. "I'd like very much to come to your father, but didn't you get my telegram, telling about the broken bridge? There is no way for me to get to Shopton in time."

"Yes, there is!" cried Tom, eagerly.

"How?"

"The same way I came—in the aeroplane! Dr. Hendrix you must go back with me! It's the only way to save my father's life. Come with me in the Humming-Bird. It's perfectly safe. I can make the trip in less than an hour. I can carry you and your instruments. Will you come? Won't you come to save my father's life?" Tom was fairly pleading now.

"A trip in an aeroplane," mused Dr. Hendrix "I've never taken such a thing. I—"

"Don't be afraid, there's really no danger," said Tom.

The physician seemed to reach a sudden conclusion. His eyes brightened. He walked over and looked at the little Humming-Bird. For the time being he forgot about his operations.

"I'll go with you!" he suddenly cried. "I'll go with you, Tom Swift! If you've got the nerve, so have I! and if my science and skill can save your father's life, he'll live to be an old man! Wait until I get my bag and I'll be with you!"

Tom's heart gave a bound of hope.



Chapter Twenty

Just in Time

While Dr. Hendrix was in his office, getting ready to make the thrilling trip through the air with Tom, the young inventor spent a few minutes going over his monoplane. The wonderful little craft had made her first big flight in excellent time, though Tom knew she could do better the farther she was flown. Not a stay had started, not a guy wire was loose. The motor had not overheated, and every bearing was as cool as though it had not taken part in thousands of revolutions.

"Oh, I can depend on you!" murmured Tom, as he looked to see that the propeller was tight on the shaft. He gave the bearing a slight adjustment to make sure of it.

He was at this when the specialist reappeared. Dr. Hendrix, after his first show of excitement, when he had made his decision to accompany Tom, had resumed his usual calm demeanor. Once again he was the grave surgeon, with his mind on the case before him.

"Well, is my auto ready?" he asked absentmindedly. Then, as he saw the little aeroplane, and Tom standing waiting beside it, he added: "Oh, I forgot for the moment that I was to make a trip through the air, instead of in my car. Well, Mr. Swift, are we all ready?"

"All ready," replied the young inventor. "We're going to make fast time, Dr. Hendrix. You'd better put this on," and Tom extended a face protector.

"What's it for?" The physician looked curiously at it.

"To keep the air from cutting your cheeks and lips. We are going to travel a hundred miles an hour this trip."

"A hundred miles an hour!" Dr. Hendrix spoke as though he would like to back out.

"Maybe more, if I can manage it," went on Tom, calmly, as he proceeded to remove the bag of sand from the place where the surgeon was to sit. Then he looked to the various equilibrium arrangements and the control levers. He was so cool about it, taking it all for granted, as if rising and flying through the air at a speed rivaling that of the fastest birds, was a matter of no moment, that Dr. Hendrix was impressed by the calm demeanor of the young inventor.

"Very well," said the surgeon with a shrug of his shoulders, "I guess I'm game, Tom Swift."

The doctor took the seat Tom pointed out to him, with his bag of instruments on his knees. He put on the face protector, and had, at the suggestion of our hero, donned a heavy coat.

"For it's cold in the upper regions," said Tom.

Several servants in the physician's household had gathered to see him depart in this novel fashion, and the chauffeur of the auto, in which the specialist usually made his calls, was also there.

"I'll give you a hand," said the chauffeur to the young inventor. "I was at an aviation meet once, and I know how it's done."

"Good," exclaimed Tom. "Then you can hold the machine, and shove when I give the word."

Tom started the propeller himself, and quickly jumped into his seat. The chauffeur held back the Humming-Bird until the young aviator had speeded up the motor.

"Let go!" cried the youthful inventor, and the man gave the little craft a shove. Across the rather uneven ground of the doctor's yard it ran, straight for a big iron barrier.

"Look out! We'll be into the fence!" shouted the surgeon. "We'll be killed!" He seemed about to leap off.

"Sit still!" cried Tom, and at that instant he tilted the elevation planes, and the craft shot upward, going over the fence like a circus horse taking a seven-barred gate.

"Oh!" exclaimed the physician in a curious voice. They were off on their trip to save the life of Mr. Swift.

What the sensations of the celebrated specialist were, Tom never learned. If he was afraid, his fright quickly gave place to wonder, and the wonder soon changed to delight as the machine rose higher and higher, acquired more speed, and soared in the air over the country that spread out in all directions from Kirkville.

"Magnificent! Magnificent!" murmured the doctor, and then Tom knew that the surgeon was in the grip of the air, and was one of the "bird-men."

Every moment the Humming-Bird increased her speed. They passed over the river near where men were working on the broken bridge. It was now no barrier to them. Tom, noting the barograph, and seeing that they were twenty-two hundred feet high, decided to keep at about that distance from the earth.

"How fast are we going?" cried Dr. Hendrix, into the ear of the young inventor.

"Just a little short of a hundred an hour!" Tom shouted back. "We'll hit a hundred and five before long."

His prediction proved true, and when about forty miles from Shopton that terrific speed had been attained. It seemed as if they were going to have a trip devoid of incident, and Tom was congratulating himself on the quick time made, when he ran into a contrary strata of air. Almost before he knew it the Humming-Bird gave a dangerous and sickening dive, and tilted at a terrifying angle.

"Are we going to turn turtle?" cried the doctor.

"I—I hope not!" gasped Tom. He could not understand why the equilibrium weights did not work, but he had no time then to investigate. Quickly he warped the wing tips and brought the craft up on an even keel.

He gave a sigh of relief as the aeroplane was once more shooting forward, and he was not mistaken when he thought he heard Dr. Hendrix murmur a prayer of thankfulness. Their escape had been a narrow one. Tom's nerve, and the coolness of the physician, had alone saved them from a fall to death.

But now, as if ashamed of her prank, the Humming-Bird went along even better than before. Tom was peering through the slight haze that hung over the earth, for a sight of Shopton. At length the spires of the churches came into view.

"There it is," he called, pointing downward. "We'll land in two minutes more."

"No time to spare," murmured the doctor, who knew the serious nature of the aged inventor's illness. "How long did it take us?"

"Fifty-one minutes," replied Tom, glancing at a small clock in front of him. Then he shut off the motor and volplaned to earth, to the no small astonishment of the surgeon. He made a perfect landing in the yard before the shed, leaped from his seat, and called:

"Come, Dr. Hendrix!"

The surgeon followed him. Dr. Gladby and Dr. Kurtz came to the door of the house. On their faces were grave looks. They greeted the celebrated surgeon eagerly.