ns, 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--"

"