r' to
douse any blaze that was ever started."

"No use sending a boy on a man's errand," said Tom. "I'm counting on
you to go with me, Ned--you and Mr. Baxter. We leave this afternoon for
Denton."

"I'll be with you. Couldn't pass up a chance like that. But here comes
Koku, and it looks as if he had something on his mind."

The giant did, indeed, seem to be laboring under the stress of some
emotion.

"Oh, Master Tom!" the big man exclaimed when he had got the attention
of the young inventor. "Rad--he--he--"

"Has anything happened?" asked Tom, quickly. "No, not yet. But dat pill
man--he say by tomorrow he know if Rad ever will see sunshine more!"

"Oh, the doctor says he'll be able to decide about Rad's eyesight
tomorrow, does he?"

"Yes. What so pill man say," repeated Koku.

"Um," mused Tom, "I wish I were going to be here, but I don't see how I
can. I must give this test." But it was with a sinking heart as he
thought of poor Eradicate that the young inventor proceeded to pile
into his airship the largest and heaviest load of chemicals it had ever
carried.

CHAPTER XXI

THE LIGHT IN THE SKY

"Well, what do you say, Tom?" asked Ned, in a low voice.

"She's all right as far as I can see, though she may stagger a bit at
the take off."

"It's a pretty heavy load," agreed the young manager, as he and Tom
Swift walked about the big fire-fighting airship Lucifer, which had
been rolled outside the hangar. "But still I think she'll take it,
especially since you've tuned up the motor so it's at least twenty per
cent. more powerful than it was."

"Perhaps you'd better leave me out," suggested Mr. Baxter, who had been
helping the boys. "I'm not a feather weight, you know."

"I need you with us," said Tom. "I want your expert opinion on the
effect the new chemicals have on the flames."

"Well, I'd like to come," admitted the chemist, "for it will be a
valuable experience for me. But I don't want an accident up in the air."

"Trust Tom Swift for that!" cried Ned. "If he says his aircraft will do
the trick, it positively will."

"How about leaving me out?" asked Mr. Damon. "I'm not an expert in
anything, as far as I know."

"You are in keeping us cheerful. And we may need you to bless things if
there's a slip-up anywhere," laughed Tom, for Mr. Damon had been
invited to be one of the party.

"I don't so much mind a slipup," said Mr. Damon, "as I do a slip down.
That's where it hurts! However, I'll