"Mostly. But come, take a look at my latest pet," and Tom arose to lead the way to another shed, a large one in the distance, toward which he waved his hand to indicate to his chum that there was housed the wonderful invention.

The two chums crossed the yard, threading their way through the various buildings, until they stood in front of the structure to which Tom had called attention.

"It's in here," he said. "I don't mind admitting that I'm quite proud of it, Ned; that is, proud as far as I've gone. But the gun business sure has me worried. I'm going to talk it off on you. Hello!" cried Tom suddenly, as he put a key in the complicated lock on the door, "someone has been in here. I wonder who it is?"

Ned was a little startled at the look on Tom's face and the sound of alarm in his chum's voice.

CHAPTER II

A FIRE ALARM

Tom Swift quickly opened the door of the big shed. It was built to house a dirigible balloon, or airship of some sort. Ned could easily tell that from his knowledge of Tom's previous inventions.

"Something wrong?" asked the young bank clerk.

"I don't know," returned Tom, and then as he looked inside the place, he breathed a sigh of relief.

"Oh, it's you, is it, Koku?" he asked, as a veritable giant of a man came forward.

"Yes, master, it is only Koku and your father," spoke the big chap, with rather a strange accent.

"Oh, is my father here?" asked Tom. "I was wondering who had opened the door of this shed."

"Yes, Tom," responded the elder Swift, coming up to them, "I had a new idea in regard to some of those side guy wires, and I wanted to try it out. I brought Koku with me to use his strength on some of them."

"That's all right, Dad. Ned and I came out to wrestle with that recoil problem again. I want to try some guns on the craft soon, but—"

"You'd better not, Tom," warned his father. "It will never work, I tell you. You can't expect to take up quick-firing guns and bombs in an airship, and have them work properly. Better give it up."

"I never will. I'll make it work, Dad!"

"I don't believe you will, Tom. This time you have bitten off more than you can chew, to use a homely but expressive statement."

"Well, Dad, we'll see," began Tom easily. "There she is, Ned," he went on. "Now, if you'll come around here..."

But Tom never finished that sentence, for at that moment there came running into the airship shed an elderly, short, stout, fussy gentleman, followed by an aged colored man. Both of them seemed very much excited.

"Bless my socks, Tom!" cried the short, stout man. "There sure is trouble!"

"I should say So, Massa Tom!" added the colored man. "I done did prognosticate dat some day de combustible material of which dat shed am composed would conflaggrate—"

"What's the matter?" interrupted Tom, jumping forward. "Speak out! Eradicate! Mr. Damon, what is it?"

"The red shed!" cried the short little man. "The red shed, Tom!"

"It's on fire!" yelled the colored man.

"Great thunderclaps!" cried Tom. "Come on—everybody on the job!" he yelled. "Koku, pull the alarm! If that red shed goes—"

Instantly the place was in confusion. Tom and Ned, looking from a window of the hangar, saw a billow of black smoke roll across the yard. But already the private fire bell was clanging out its warning. And, while the work of fighting the flames is under way, I will halt the progress of this story long enough to give my new readers a little idea of who Tom Swift is, so they may read this book more intelligently. Those of you who have perused the previous volumes may skip this part.

Tom Swift, though rather young in years, was an inventor of note. His tastes and talents were developed along the line of machinery and locomotion. Motorcycles, automobiles, motorboats, submarine craft, and, latest of all, craft of the air, had occupied the attention of Tom Swift and his father for some years.

Mr. Swift was a widower, and lived with Tom, his only son, in the village of Shopton, New York State. Mrs. Baggert kept house for them, and an aged colored man, Eradicate Sampson, with his mule, Boomerang, did "odd jobs" about the Shopton home and factories.

Among Tom's friends was a Mr. Wakefield Damon, from a nearby village. Mr. Damon was always blessing something, from his hat to his shoes, a harmless sort of habit that seemed to afford him much comfort. Then there was Ned Newton, a boyhood chum of Tom's, who worked in the Shopton bank. I will just mention Mary Nestor, a young lady of Shopton, in whom Tom was more than ordinarily interested. I have spoken of Koku, the giant. He really was a giant of a man, of enormous strength, and was one of two whom Tom had brought with him from a strange land where Tom was held captive for a time. You may read about it in a book devoted to those adventures.

Tom took Koku into his service, somewhat to the dismay of Eradicate, who was desperately jealous. But poor Eradicate was getting old, and could not do as much as he thought he could. So, in a great measure, Koku replaced him, and Tom found much use for the giant's strength.

Tom had begun his inventive work when, some years before this story opens, he had bargained for Mr. Damon's motorcycle, after that machine had shot its owner into a tree. Mr. Damon was, naturally, perhaps, much disgusted, and sold the affair cheap. Tom repaired it, made some improvements, and, in the first volume of this series, entitled "Tom Swift and His Motor-cycle," you may read of his rather thrilling adventures on his speedy road-steed.

From then on Tom had passed a busy life, making many machines and having some thrilling times with them. Just previous to the opening of this story Tom had made a peculiar instrument, described in the volume entitled "Tom Swift and His Photo-Telephone." With that a person talking could not only see the features of the person with whom he was conversing, but, by means of a selenium plate and a sort of camera, a permanent picture could be taken of the person at either end of the wire.

By means of this invention Tom had been able to make a picture that had saved a fortune. But Tom did not stop there. With him to invent was as natural and necessary as breathing. He simply could not stop it. And so we find him now about to show to his chum, Ned Newton, his latest patent, an aerial warship, which, however, was not the success Tom had hoped for.

But just at present other matters than the warship were in Tom's mind. The red shed was on fire.

That mere statement might not mean anything special to the ordinary person, but to Tom, his father, and those who knew about his shops, it meant much.

"The red shed!" Tom cried. "We mustn't let that get the best of us! Everybody at work! Father, not you, though. You mustn't excite yourself!"

Even in the midst of the alarm Tom thought of his father, for the aged man had a weak heart, and had on one occasion nearly expired, being saved just in time by the arrival of a doctor, whom Tom brought to the scene after a wonderful race through the air.

"But, Tom, I can help," objected the aged inventor.

"Now, you just take care of yourself, Father!" Tom cried. "There are enough of us to look after this fire, I think."

"But, Tom, it—it's the red shed!" gasped Mr. Swift.

"I realize that, Dad. But it can't have much of a start yet. Is the alarm ringing, Koku?"

"Yes, Master," replied the giant, in correct but stilted English. "I have set the indicator to signal the alarm in every shop on the premises."

"That's right." Tom sprang toward the door. "Eradicate!" he called.

"Yais, sah! Heah I is!" answered the colored man. "I'll go git mah mule, Boomerang, right away, an' he—"

"Don't you bring Boomerang on the scene!" Tom yelled. "When I want that shed kicked apart I can do it better than by using a mule's heels. And you know you