out a
powerful, though small, searchlight attached to an adaptable arm in the
same manner as a desk telephone.

There was a clicking sound, and a flood of white light pierced the
blackness outside. The boys broke into delighted exclamations as the
powerful rays revealed all sorts of fish, many of odd shapes and colors,
attracted by the light.

Suddenly a dark, shadowy form swung into view. Instantly the other fish
vanished, and the boys saw that the newcomer was a large shark swimming
leisurely along.

No doubt he wondered who the strangers in his deep sea abode could be,
for he swam up close to the window, causing the boys to shrink back.
They quite forgot that between them and the tiger of the deep was a
solid plate of glass as strong almost as steel.

The shark gazed at the window for an instant and then vanished. With its
disappearance, the other fish reappeared and kept the submarine company,
for all the world like sea gulls circling round a ship entering port.

"I wonder if they are hungry and want us to throw some food out to
them," said Tubby stolidly, as he gazed at the finny tribes darting here
and there in the searchlight's rays.

"Gracious, do you think that the fish have the same appetite as you
have?" laughed Merritt.

"Just the same, some of those fellows would taste all right broiled,"
declared the stout youth, at which there was a general laugh.

After an hour spent in this manner the searchlight was switched off and
the panels slid back into place.

"I think we will rise now," said the inventor; "you boys had better hold
on, for we may go up pretty quick."

"I hope we _do_ go up," muttered Tubby, rather nervously. The stout
youth was not particularly in love with the dark depths in which they
were navigating. In fact, all the lads, though they did not admit it,
experienced a longing for daylight. It was an awe-inspiring feeling--too
awe-inspiring to be comfortable--to be in the depths of the ocean where
no keel had ever before plowed.

Mr. Barr remounted to the conning tower. A minute later a renewal of the
swishing sound told that the pumps were emptying the tanks at the rate
of a thousand gallons a minute. The submarine could be felt to leap
upward toward the surface. The boys held on for dear life, exchanging
rather alarmed glances.

All at once the pace slackened, and the swishing sound ceased. Mr. Barr
had decided that the pace was too swift and had cut off the pumps.

"Well, tha