ed with minute sketches,
apparently of machinery. The sketches were numbered and lettered, as if
they had been "keyed" for the purpose of making the diagram clearer.

He was still examining the sketches when there was a swift step behind
him and a heavy hand fell on his shoulder. Rob, facing about, looked
into Barton's face. The engineer's countenance was livid, his eyes
fairly blazed.

"Give me that paper, you young jackanapes!" he exclaimed, "and then get
out of here--quick!"

"As to giving you the paper, here you are," said Rob, quietly handing
the engineer the mechanical sketches. "If I'd known they were yours, I'd
have returned them to you at once. I must ask you, however, to be a
little less rough in your manners. I don't know what harm we've ever
done you, that you should show such a dislike for us."

"Bah!" growled Barton as he turned away, thrusting the paper into a
pocket of his jumper.

After this incident neither of the boys cared to remain in the engine
room, and soon joined their companions in the main cabin.

They found them chatting and laughing over different boyish topics, and
Merritt joined in the fun.

But Rob, usually talkative and bright, was strangely silent. He found
himself musing over the incident of the scrap of paper covered with
mechanical sketches. Why had Barton become so agitated when the boy
picked it up? What was there about the affair to excite the man so
strangely?

Suddenly into the boy's mind there flashed a startling suspicion. But so
grave was the idea that he dismissed it, or rather tried to; but with
all his efforts the idea kept recurring like a dominant note in a piece
of music. Rob decided to be on the watch and try to verify or disprove
his suspicion, which was nothing more nor less than an idea that Barton
was a traitor to his employer, and was also in the service of some
powerful interests striving to get a grip on the secrets of the
_Peacemaker_.

"That man will bear watching," decided Rob.

Scarcely had he come to this conclusion when Mr. Barr shouted down from
the conning tower:

"I'm going to dive!"

The hearts of all the lads beat perceptibly quicker at the words.

They were about to descend into the unknown regions beneath the surface
of the ocean, down into the dark waters where men's souls are put to a
supreme test.

CHAPTER XIV.

FACING DEATH.

"Ready?" came the cry from the conning tower.

"All ready!" shouted back the lads assembl