rious.

"If we go much deeper, I'll sure let out a yell," Eph gritted, between
his teeth.

At last Jack's voice broke in, coolly:

"You see, gentlemen, the gauge now gives a constant reading. We can't
go any lower, for the water tanks are as full as they'll hold, and
there's still the buoyancy caused by all the air the interior of the
boat. So we're as far below the surface as we can go."

"Bully for you, Benson!" cried Lieutenant McCrea, slapping the young
skipper on the back. "You understand what you're doing, and no one
could do it with more coolness. You must have been born aboard a
submarine."

"He never saw a craft of this kind, until a few weeks ago," retorted
Jacob Farnum admiringly.

Taking out a notebook and pencil, Commander Ennerling recorded the
reading of the submergence gauge, which showed how many feet the craft
was below the surface of the water.

"Of course," hinted Mr. Farnum, smilingly, "don't know the gauge to be
correct."

"We've the means with us of testing and standardizing the gauge in the
harbor," replied the president of the board.

"If we ever see the harbor again," muttered Eph Somers, overhead in the
conning tower.

"How does this compare with the depths touched by submarine boats now
owned by the Navy?" asked David Pollard, a bit feverishly. He was not
afraid of their present rather dangerous position, but was frightfully
nervous over the thought of any good showing this craft born in his
brain might fail to make. "This is thirty feet lower than any
submarine record I've ever heard of."

"I--perhaps it would be wiser for me not to say," replied Commander
Ennerling. "It may be as well for me to wait and compare this record
with those on file at the Navy Department."

"Have you had all you want of this, gentlemen?" inquired the boatbuilder.
"Shall we show you anything else?"

"Yes; you might give us a run at full speed under water, at the lowest
depth that you deem it wise to try to run the craft," answered the
president of the board.

"Very good," nodded the builder. Hal took this as the signal to leap
back into the motor room.

"How far below the surface would _you_ dare run the 'Pollard,' Captain
Benson?" inquired Commander Ennerling.

"At the greatest depth we can go, the present depth," quietly answered
Jack, without bravado.

The president of the board glanced at the builder of the submarine.

"Does that appeal to you, Mr. Farnum?"

"I'll let Captain