"

He continued his march up and down for a while, and then stopped once
more, grounded his piece, and stood there quite invisible to anyone a
few yards away. He went on thinking about the town at the head of the
bay, and the music, and of how time was going; and then his thoughts
went back to the great body of dangerous criminals shut up in the huge,
grim buildings, and of how much depended on the care and diligence of
those in charge--a mere handful compared to those they guarded.

"Only we've got the law on our side and they haven't," he thought; and
as the thought ran through his brain he felt the blood pulsate sharply
and there was a heavy throb at his heart, for there was a peculiar sound
away to his right, high up the steep slope of the cliff, as if a stone
had been dislodged and had slipped down a few yards before stopping in a
cleft. He stood listening intently, but the sound was not repeated--all
was still as death; but the man's pulses had been stirred, and his heart
beat in a manner that was painful.

It was not that he was particularly wanting in courage, but, shut in
there by the darkness, it was impossible to keep back the thought that a
desperate man who had stolen out or hidden might be lurking close by
ready to spring upon him in an unguarded moment, drive him off the cliff
shelf which formed his beat, and all would be over in an instant. For a
fall there meant death by drowning or the fearful crash on to the rocks
below.

"They shan't take me unawares," he thought, and then he hesitated as to
whether he should give the alarm by firing his piece.

In an instant he had raised it and his finger was on the trigger, but he
did not make its flash cut the darkness for a moment and its report run
re-echoing along the cliffs.

"What for?" he said to himself; "bring the fellows here to laugh at me
because I heard a rabbit on the move. I should never hear the last of
it."

He again grounded his piece, but very softly, and stood with his back to
the sea, straining his eyes in the direction from whence the sound had
come, but the stones that towered up were all blurred together into one
black mass, and though he fancied several times over that he could make
out the figure of a man half-hidden by some projection, he was fain to
confess directly after that it was all fancy.

"But fancy or not," he said to himself, "I don't mean to be taken on the
grand hop,"--and he did not stir from his position where