My friend, Mr. Sharp, the balloonist, and I were
conducting an experiment with a new kind of gas, and it was too strong,
that's all. An aluminum container blew up, but no particular damage was
done. I hope you're satisfied."

"Humph! What you making, anyhow?" demanded Andy, and again he spoke as
if he had a right to know.

"I don't know that it's any of your business," Tom came back at him
sharply, "but, as everyone will soon know, I may as well tell you.
We're building an airship."

"An airship?" exclaimed Sam and Pete in one breath.

"An airship?" queried Andy, and there was a sneer in his voice. "Well,
I don't think you can do it, Tom Swift! You'll never build an airship;
even if you have a balloonist to help you!"

"I won't, eh?" and Tom was a trifle nettled at the sneering manner of
his rival.

"No, you won't! It takes a smarter fellow than you are to build an
airship that will sail. I believe I could beat you at it myself."

"Oh, you think you could?" asked Tom, and this time he had mastered his
emotions. He was not going to let Andy Foger make him angry. "Maybe
you can beat me at racing, too?" he went on. "If you think so, bring
out your Red Streak and I'll try the Arrow against her. I beat you
twice, and I can do it again!"

This unexpected taunt disconcerted Andy. It was the truth, for, more
than once had Tom, in his motor-boat, proved more than a match for the
squint-eyed bully and his cronies.

"Go back at him, Andy," advised Sam, ire low voice. "Don't take any of
his guff!"

"I don't intend to," spluttered Andy. "Maybe you did beat me in the
races, because my motor wasn't working right," he conceded, "but you
can't do it again. Anyhow, that's got nothing to do with an airship.
I'll bet you can't make one!"

"I don't bet," replied Tom calmly, "but if you wait a few weeks you'll
see me in an airship, and then, if you want to race the Red Streak
against that, I'll accommodate you. Or, if you want to enter into a
competition to build a dirigible balloon or an aeroplane I'm willing."

"Huh! Think you're smart, don't you? Just because you helped save that
balloonist from being killed when his balloon caught fire," went on
Andy, for want of something better to say. "But you'll never build an
airship!"

"Of course he won't!" added Sam and Pete, bound to side with their
crony, to whom they were indebted for many automobile and motor-boat
rides.

"Just wait," advised Tom, with a tantalizing smile.