ed in the cabin, waiting for
they knew not what.

"Then hold tight, we're going down quick."

S-w-ish-ish-ish! The roar of the water, as the powerful pumps sucked it
into the submerging tanks, filled the interior of the Barr submarine.
Suddenly she gave a forward plunge, and the boys now learned for what
purpose several handholds were attached to the cabin walls!

"Say, this is a queer sensation, isn't it?" gasped Merritt, looking
rather alarmed as the downward rush could be distinctly felt. In the
engine room the electric motors had been connected, and in the conning
tower the hatch which gave entrance and egress when on the surface had
been clamped tightly down.

"S-s-pose we don't come up again?" exclaimed Donald.

"We haven't got an awful lot to eat on board," murmured Tubby anxiously.

"Gracious, how far down are we going?" spoke Merritt, as five minutes
passed and still the _Peacemaker_ continued her descent into the depths
of the sea.

All at once the tilting motion ceased, the _Peacemaker's_ stern tanks
were filled, and she floated on an even keel. Leaving the care of the
wheel to Ensign Hargreaves, who, as we know, was familiar with the usual
type of submarine, Mr. Barr came into the cabin.

"Well, boys, what do you think of it?" he asked with a smile.

"It's g-g-great," rejoined Tubby, with a notable lack of his usual
assurance.

"And now I suppose you'd like to see what the bottom of the sea looks
like. We are down some two hundred fathoms and about fifty miles off the
coast. Should you care to see how things look down here?"

"How will that be possible?" asked Merritt.

By way of reply Mr. Barr went to the starboard wall of the cabin and
pulled a lever connecting with a worm gear. As he did so, a great
section of the _Peacemaker's_ steel side drew back and revealed a plate
glass window set between the inner and outer "skins" of the craft.

The boys crowded round the window and peered out eagerly. But to their
disappointment they could see no more of their surroundings than if they
had been looking out of a train window on a dark night. It was as black
as a wolfs mouth at those unknown depths.

"Why, we can't see anything," came a disgruntled chorus.

"Wait a minute," smiled the inventor.

[Illustration: THE BOYS CROWDED ROUND THE WINDOW AND PEERED OUT
EAGERLY.]

Pressing a button, he extinguished the cabin lights. Then he opened a
sort of closet in the wall alongside the window and swung