Chapter I. Tom is Puzzled
 

"What's the matter, Tom? You look rather blue!"

"Blue! Say, Ned, I'd turn red, green, yellow, or any other color of the rainbow, if I thought it would help matters any."

"Whew!"

Ned Newton, the chum and companion of Tom Swift, gave vent to a whistle of surprise, as he gazed at the young fellow sitting opposite him, near a bench covered with strange-looking tools and machinery, while blueprints and drawings were scattered about.

Ranged on the sides of the room were models of many queer craft, most of them flying machines of one sort or another, while through the open door that led into a large shed could be seen the outlines of a speedy monoplane.

"As bad as that, eh, Tom?" went on Ned. "I thought something was up when I first came in, but, if you'll excuse a second mention of the color scheme, I should say it was blue--decidedly blue. You look as though you had lost your last friend, and I want to assure you that if you do feel that way, it's dead wrong. There's myself, for one, and I'm sure Mr. Damon--"

"Bless my gasoline tank!" exclaimed Tom, with a laugh, in imitation of the gentleman Ned Newton had mentioned, "I know that! I'm not worrying over the loss of any friends."

"And there are Eradicate, and Koku, the giant, just to mention a couple of others," went on Ned, with a smile.

"That's enough!" exclaimed Tom. "It isn't that, I tell you."

"Well, what is it then? Here I go and get a half-holiday off from the bank, and just at the busiest time, too, to come and see you, and I find you in a brown study, looking as blue as indigo, and maybe you're all yellow inside from a bilious attack, for all I know."

"Quite a combination of colors," admitted Tom. "But it isn't what you think. It's just that I'm puzzled, Ned."

"Puzzled?" and Ned raised his eyebrows to indicate how surprised he was that anything should puzzle his friend.

"Yes, genuinely puzzled."

"Has anything gone wrong?" Ned asked. "No one is trying to take any of your pet inventions away from you, is there?"

"No, not exactly that, though it is about one of my inventions I am puzzled. I guess I haven't shown you my very latest; have I, Ned?"

"Well, I don't know, Tom. Time was when I could keep track of you and your inventions, but that was in your early days, when you started with a motorcycle and were glad enough to have a motorboat. But, since you've taken to aerial navigation and submarine work, not to mention one or two other lines of activity, I give up. I don't know where to look next, Tom, for something new."

"Well, this isn't so very new," went on the young inventor, for Tom Swift had designed and patented many new machines of the air, earth and water. "I'm just trying to work out some new problems in aerial navigation, Ned," he went on.

"I thought there weren't any more," spoke Ned, soberly enough.

"Come, now, none of that!" exclaimed Tom, with a laugh. "Why, the surface of aerial navigation has only been scratched. The science is far from being understood, or even made safe, not to say perfected, as water and land travel have been. There's lots of chance yet."

"And you're working on something new?" asked Ned, as he looked around the shop where he and Tom were sitting. As the young bank employee had said, he had come away from the institution that afternoon to have a little holiday with his chum, but Tom, seated in the midst of his inventions, seemed little inclined to jollity.

Through the open windows came the hum of distant machinery, for Tom Swift and his father were the heads of a company founded to manufacture and market their many inventions, and about their home were grouped several buildings. From a small plant the business had grown to be a great tree, under the direction of Tom and his father.

"Yes, I'm working on something new," admitted Tom, after a moment of silence.

"And, Ned," he went on, "there's no reason why you shouldn't see it. I've been keeping it a bit secret, until I had it a little further advanced, but I've got to a point now where I'm stuck, and perhaps it will do me good to talk to someone about it."

"Not to talk to me, though, I'm afraid. What I don't know about machinery, Tom, would fill a great many books. I don't see how I can help you," and Ned laughed.

"Well, perhaps you can, just the same, though you may not know a lot of technical things about machines. It sometimes helps me just to tell my troubles to a disinterested person, and hear him ask questions. I've got dad half distracted trying to solve the problem, so I've had to let up on him for a while. Come on out and see what you make of it."

"Sure, Tom, anything to oblige. If you want me to sit in front of your photo-telephone, and have my picture taken, I'm agreeable, even if you shoot off a flashlight at my ear. Or, if you want me to see how long I can stay under water without breathing I'll try that, too, provided you don't leave me under too long, lead the way--I'm agreeable as far as I'm able, old man."

"Oh, it isn't anything like that," Tom answered with a laugh. "I might as well give you a few hints, so you'll know what I'm driving at. Then I'll take you out and show it to you."

"What is it--air, earth or water?" asked Ned Newton, for he knew his chum's activities led along all three lines.

"This happens to be air."

"A new balloon?"

"Something like that. I call it my aerial warship, though."

"Aerial warship, Tom! That sounds rather dangerous!"

"It will be dangerous, too, if I can get it to work. That's what it's intended for."

"But a warship of the air!" cried Ned. "You can't mean it. A warship carries guns, mortars, bombs, and--"

"Yes, I know," interrupted Tom, "and I appreciate all that when I called my newest craft an aerial warship."

"But," objected Ned, "an aircraft that will carry big guns will be so large that--"

"Oh, mine is large enough," Tom broke in.

"Then it's finished!" cried Ned eagerly, for he was much interested in his chum's inventions.

"Well, not exactly," Tom said. "But what I was going to tell you was that all guns are not necessarily large. You can get big results with small guns and projectiles now, for high-powered explosives come in small packages. So it isn't altogether a question of carrying a certain amount of weight. Of course, an aerial warship will have to be big, for it will have to carry extra machinery to give it extra speed, and it will have to carry a certain armament, and a large crew will be needed. So, as I said, it will need to be large. But that problem isn't worrying me."

"Well, what is it, then?" asked Ned.

"It's the recoil," said Tom, with a gesture of despair.

"The recoil?" questioned Ned, wonderingly.

"Yes, from the guns, you know. I haven't been able to overcome that, and, until I do, I'm afraid my latest invention will be a failure."

Ned shook his head.

"I'm afraid I can't help you any," he said. "The only thing I know about recoils is connected with an old shotgun my father used to own.

"I took that once, when he didn't know it," Ned proceeded. "It was pretty heavily loaded, for the crows had been having fun in our cornfield, and dad had been shooting at them. This time I thought I'd take a chance.

"Well, I fired the gun. But it must have had a double charge in it and been rusted at that. All I know is that after I pulled the trigger I thought the end of the world had come. I heard a clap of thunder, and then I went flying over backward into a blackberry patch."

"That was the recoil," said Tom.

"The what?" asked Ned.

"The recoil. The recoil of the gun knocked you over.

"Oh, yes," observed Ned, rubbing his shoulder in a reflective sort of way. "I always thought it was something like that. But, at the time I put it down to an explosion, and let it go at that."

"No, it wasn't an explosion, properly speaking," said Tom. "You see, when powder explodes, in a gun, or otherwise, its force is exerted in all directions, up, down and every way.

"This went mostly backward--in my direction," said Ned ruefully.

"You only thought so," returned Tom. "Most of the power went out in front, to force out the shot. Part of it, of course, was exerted on the barrel of the gun--that was sideways--but the strength of the steel held it in. And part of the force went backward against your shoulder. That part was the recoil, and it is the recoil of the guns I figure on putting aboard my aerial warship that is giving me such trouble."

"Is that what makes you look so blue?" asked Ned.

"That's it. I can't seem to find a way by which to take up the recoil, and the force of it, from all the guns I want to carry, will just about tear my ship to pieces, I figure."

"Then you haven't actually tried it out yet?" asked Ned.

"Not the guns, no. I have the warship of the air nearly done, but I've worked out on paper the problem of the guns far enough so that I know I'm up against it. It can't be done, and an aerial warship without guns wouldn't be worth much, I'm afraid."

"I suppose not," agreed Ned. "And is it only the recoil that is bothering you?"

"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.