it---I'll show you how."

"This is pretty hard on men in the middle of the night," hinted Evarts,
after the jogging had gone on for a full minute. "It ain't right to-----"

"Stop it, Evarts!" Tom cut in crisply. "I don't mind a little grumbling
at the right time, and I often do a bit myself, but not when I'm as rushed
as I am to-night. There's the dock ahead, men---a little faster spurt
now!"

Tom urged his men along to the dock. With no loss of time they tumbled
aboard the "Morton," a broad, somewhat shallow, forty-foot motor boat of
open construction.

"Get up and take the wheel, Evarts," Tom. directed. "Get at work on your
spark, Conlon, and I'll throw the drive-wheel over for you. Some of you
men cast, off!"

In a very short time the "Morton" was going "put-put-put" away from the
dock.

Tom, after seeing that everything was moving satisfactorily, turned around
to look at the four men huddled astern.

"Don't any of you go to sleep," he urged. "A good part of our success
depends on how well you all keep awake and use your eyes and ears."

That said, Tom Reade hastened forward, stationing himself close to Evarts,
who had the steering wheel.

Some of the men astern began to talk.

"Silence, if you please," Tom called softly. "Don't talk except on matters
of business. We want to be able to use our ears. Conlon, make your engine
a little less noisy if you can."

Now Reade had leisure to wonder how matters had gone with Harry Hazelton.

"Of course that threatening figure Harry saw behind him was an imaginary
one," Tom said to himself, but he felt uneasy nevertheless.

A few moments later Reade clutched at one of Evarts's arms.

"Did you hear that, man?" the young engineer demanded.

"Hear what?" Evarts wanted to know.

"It sounded like a yell out there yonder," Tom rejoined.

"Didn't hear it, Mr. Reade."

"There it goes again!" cried Tom, leaping up. "Some one is calling my
name. It must be Harry Hazelton, and he must want help. Conlon, slam it
to that engine of yours!"

CHAPTER III

VANISHING INTO THIN AIR

Left by himself Harry had stood, at first, motionless, or nearly so. He
strained his hearing in trying to detect any unusual sound of the night,
since it was so dark that vision would not aid him much.

There was nothing, however, but the mournful sighing of the wind and the
lapping of the waves. It seemed to Hazelton that the wind was growing
gradually more brisk and