" murmured Ned. "If only moving pictures of
this could be taken in colors, it would create a sensation."

"Perhaps I may try that some day," said Tom with a smile. "But just now
I have something else to do. Ned, are you game for another try in the
diving dress? I want to see how it operates with a new air tank I've
fitted on. Want to try?"

"Sure I'll go out," was the ready answer. "It's nicer walking around on
this white sand than on the black mud where we saw the whales. You can
see better, too."

A little later he and one of the sailors were outside the submarine,
walking around in the diving dress, while Tom and the others watched
through the glass windows. The new air tank seemed to be working well,
for Ned, coming close to the window, signaled that he was very
comfortable.

He walked around with the sailor, breaking off bits of odd-shaped coral
to bring back to Tom. Suddenly, as those inside the craft looked out,
they saw the sailor turn from Ned's side, and with a warning hand,
point to something evidently approaching. The next instant a queer
shape seemed to envelope Ned Newton, coming out from behind a ledge of
weed-draped coral. And a cry went up from those in the submarine as Ned
was seen to be enveloped in long, waving arms.

"An octopus!" cried Mr. Damon. "Bless my soul, Tom, an octopus has Ned!"

"No, it isn't that!" cried the young inventor hoarsely. "It's some
other monster. It has only five arms--an octopus has eight! I've got
to save Ned!"

And he hurried toward the diving chamber, while the others, in
fascinated horror, looked at the diver who was in such strange peril.

CHAPTER XV

TOM TO THE RESCUE

Mr. Damon came to a pause in the compartment from which the diving
chamber gave access to the ocean outside. Tom, standing before the
sliding steel door, had summoned to him several of his men and was
rapidly giving them directions.

"What are you going to do, Tom Swift?" asked the eccentric man.

"I'm going out there to save Ned!" was the quick answer. "He's in the
grip of some strange monster of the sea. What it is I don't know, but
I'm going to find out. Koku, you come with me!"

"Yes, Master, me come!" said the giant simply, as if Tom had told him
to go for a pail of water instead of risking his life.

"Barnes, the electric gun!" cried the young inventor to one of his
helpers, while others were getting out the diving suits.

"The electric gun!" exclaimed the man. "Do you