her.

"About six hundred feet, I judge, going by the character of the sea
bottom around here. Certainly not more than eight hundred I should
say." And Tom was right. At seven hundred and eighty-six feet the gauge
stopped moving, and a slight jar told all on board that the submarine
was again on the ocean floor.

"Now to look for the wreck!" exclaimed Tom. "And it will be a real
search this time. We know we are starting right."

"Are you going to put on diving suits and walk around looking for her?"
asked Ned.

"No, that would take too long," answered Tom. "We'll just cruise about,
beginning with small circles and gradually enlarging them, spiral
fashion. We'll have to go up a few feet to get off the bottom."

As Tom was about to give this order Ned looked from the glass windows.
The powerful searchlight had been switched on and its gleams
illuminated the ocean in the immediate vicinity of the craft.

As was generally the case, the light attracted hundreds of fish of
various shapes, sizes, and, since the waters were tropical, beautiful
colors. They swarmed in front of the glass windows, and Ned was glad to
note that there were no large sea creatures, like horse mackerel or big
sharks. Somehow or other, Ned had a horror of big fish. There were
sharks in the warm waters, he well knew, but he hoped they would keep
away, even though he did not have to encounter any in the diving suit.

Slowly the submarine began to move. And as she was being elevated
slightly above the ocean bed, to enable her to proceed, Ned uttered an
exclamation and pointed to the windows.

"Look, Tom!" he cried.

"What is it?" the young inventor asked.

"Snakes!" whispered his chum. "Millions of 'em! Out there in the water!
Look how they're writhing about!"

Tom Swift laughed.

"Those aren't snakes!" he said. "That's serpent grass--a form of very
long seaweed which grows on certain bottoms. It attains a length of
fifty feet sometimes, and the serpent weed looks a good deal like a
nest of snakes. That's how it got its name. I didn't know there was any
here. But we must have dropped down into a bed of it."

"Any danger?" asked Ned.

"Not that I know of, only it may make it more difficult for us to see
the wreck of the Pandora."

As Tom turned to leave the cabin the submarine suddenly ceased moving.
And she came to a gradual stop as though she had been "snubbed" by a
mooring line.

"I wonder what's the matter!" exclaimed Tom. "We can't