e acids!" he cried. "They're generating gas! And I'm held fast
here! The place is closed up tight, and I can't move! Help! Help!"

But there was no one at hand to aid Tom, and every moment the fumes of
the gas became stronger. Desperately the youth struggled to rid himself
of the weight of the shaft, but he could not. And then he felt his
senses leaving him, for the powerful gas was making him unconscious.

CHAPTER V

TOM GETS A WARNING

"Bless my shoe buttons!" exclaimed a voice, as a man came toward Tom's
shop, a little later. "Bless my very necktie! This is odd. I go to the
house, and find no one there. I come out here, and not a soul is about.
Tom Swift can't have gone off on another one of his wonderful trips,
without sending me word. I know he wouldn't do that. And yet, bless my
watch and chain, I can't find any one!"

It was Mr. Damon who spoke, as my old readers have already guessed. He
peered into one of the shop windows, and saw something like a fog
filling the place.

"That's strange," he went on. "I don't see Tom there, and yet it looks
as if an experiment was going on. I wonder--"

Mr. Damon heard some one coming up behind him, and turned to see Koku
the giant, who was returning from the errand on which Tom had sent him.

"Oh, Koku, it's you; is it?" the odd man asked. "Bless my cuff buttons!
Where is Tom?"

"In shop I guess."

"I don't see him. Still I had better look. There doesn't seem to be any
one about."

Mr. Damon opened the shop door, and was met by such an outward rush of
choking gas that he staggered back.

"Bless my--" he began but he had to stop, to cough and gasp. "There
must have been some sort of an accident," he cried, as he got his lungs
full of fresh air. "A bad accident! Tom could never work in that
atmosphere. Whew!"

"Accident! What is matter?" cried Koku stepping to the doorway. He,
too choked and gasped, but his was such a strong and rugged nature, and
his lungs held such a supply of air, that it took more than mere gas to
knock him out. He peered in through the wreaths of the acid vapor, and
saw the body of his master, lying on the floor--held down by the heavy
iron.

In another instant Koku had rushed in, holding his breath, for, now
that he was inside the place, the gas made even him feel weak.

"Come back! Come back!" cried Mr. Damon. "You'll be smothered! Wait
until the gas escapes!"

"Then Mr. Tom die!" cried the giant. "I get him--or I no come o