to operate successfully. Ned made a pretense of looking for treasure
amid the sand and seaweed, and once he caught and held up by its tail a
queer turtle. Koku stalked about behind Ned, looking to right and left,
possibly for a sight of some monster "cow fish."

"They're coming back in, I think," remarked Tom, when he saw Ned turn
and start back for the side of the craft, where, amidships, was located
the diving chamber. "They're satisfied with the test."

Suddenly Koku was seen to glide to the side of Ned, and point at
something which none of the observers in the M. N. 1 could see. The
giant was evidently perturbed, and Ned, too, showed some agitation.

"Bless my rubber shoes! what's the matter?" cried Mr. Damon.

"I don't know," answered Tom. "Perhaps they have sighted a wreck, or
something like that."

"Look! It's a sea monster!" cried Mr. Hardley. "I can see the form of
some great fish, or something. Look! It's coming right at them!"

As he spoke all in the observation chamber saw a great, black form, as
if of some monster, move close to the two divers.

CHAPTER XIV

IN STRANGE PERIL

"What is it, Tom? What is it?" cried Mr. Damon, not stopping in this
moment of excitement to bless anything. "What is going to attack Ned
and Koku?"

"I don't know," answered the young inventor. "It's some big fish
evidently. I must get to the diving chamber!"

He gave a quick glance through the observation windows. Ned and the
giant were moving as fast as they could toward the side of the craft
where they could enter. The black, shadowy form was nearer now, but its
nature could not be made out.

Calling to his force of assistants, Tom stood ready to let his chum and
Koku out of the diving chamber as soon as the water should have been
pumped from it.

A little later, as they all stood waiting in tense eagerness, there
came a signal that the two divers had entered the side chamber. Quickly
Tom turned the lever that closed the outer door.

"They're safe!" he exclaimed, as he started the pumps to working. But
even as he spoke they felt a jar, and the submarine rolled partly over
as if she had collided with some object. Yet this could not be, as she
was stationary on the floor of the ocean.

"Bless my cake of soap, Tom!" cried Mr. Damon, "what in the world is
that?"

"If it's an accident!" exclaimed Mr. Hardley, "I think it ought to be
prevented. There have been too many happenings on this trip already. I
thou