a tunnel at no great depth beneath the
surface of the earth. The sound, dull and muffled still, swept rapidly
toward him from seaward, and at the moment of its greatest intensity
there was for an instant a vibrating jar of the ground beneath his feet;
the next moment it had passed, and the sound swept onward toward the
interior of the island until it again became lost in the hollow roar of
the distant breakers.

Somewhat startled by this singular and unusual phenomenon, Dickinson
hurried forward, and soon stood beneath the walls of the cottage. A
light was still burning in one of the upper rooms; so, seizing a handful
of fine gravel, he flung it against the window in the hope of quietly
attracting the attention of the inmates. After two or three essays his
efforts were rewarded with success, the window being softly opened and
Bowles' head thrust out, with the low-spoken ejaculation:

"Hillo, below there!"

"It's me--Dickinson," was the equally low-spoken response. "If you're
not all turned-in I'd be glad to have a few words with some of yer."

"All right, my lad!" said Bowles. "I'll be down in a jiffey. Nothing
else gone wrong, I hope?"

"No," said Dickinson; "I only wants to make a few arrangements; that's
all."

In another minute the ladder was cautiously lowered, and Rex and Bowles
joined their visitor.

"I say, gen'lemen, did you hear anything _pecoolyer_ a few minutes ago?"
was Dickinson's first remark.

"Yes," said Rex; "did you? Unless I am greatly mistaken we have been
visited by a slight shock of earthquake."

"'Arthquake, eh? Well, if 'tain't nothing worse than that I don't
mind," was the response. "You see I don't know much about 'arthquakes,
not bein' used to 'em, and I felt a bit scared just at first, I own; but
if so be as it's only a 'arthquake, why that's all right. If anything
like that happens I like to know, if it's only to keep my mind quiet.
But that ain't what I've come up here to rouse you gen'lemen out in the
middle watch about; it's just this here."

And therewith he proceeded to lay before his hearers his own view of the
state of affairs, pointing out to them the fact--already keenly
recognised by them--that the moment for action might now present itself
at any time, and explaining his own anxiety for a definite arrangement
of some plan of operations, together with an agreement upon certain
preconcerted signals to be of such a character as should be easily
understood by t