they were
wont to be quite active about the peep of day, he resolved to bide by
his voluntary watch a little longer. He beckoned Sergeant Vigilant to
his side and the two sat down to rest among the delicate ferns that
covered the ridge. They went over again the events of the night, putting
this and that together, in order to frame some intelligent theory for
their guidance. MacWhirlie, however, could find nothing to shake his
first conclusion.

"The danger must have come upon them unawares," said he; "it was clearly
in every case a complete surprise. If an enemy had approached from the
front, he would have been spied in time for an alarm. A surprise so
thorough could only have come from the direction of our own camp, as
that was the only quarter not carefully watched."

The Sergeant's reply was arrested by a curious phenomenon. The ground
beneath them seemed to be trembling; it raised slowly, swayed back and
forth, and then sank down. The Brownies jumped to their feet and
MacWhirlie exclaimed:

"What is that? Did you notice the shaking of the earth? or was it only
the grass rocking in the wind?"

"It was--it seemed to be an earthquake," answered Vigilant. "There! I
feel the ground again trembling beneath us."

[Illustration: FIG. 117.--A Trap-door Opened.]

The earth had, indeed, begun to lift up like a wave; higher and higher
it rose, until the officers, finding that they were losing their
perpendicular, flung themselves backward, in true Brownie fashion, into
a bush on the summit of the ridge.

"See!" cried MacWhirlie, clasping the Sergeant by the arm, "there is the
enchantress of your haunted ground!"

[Illustration: FIG. 118.--A Trap-door Closed.]

A trap-door had opened in the ground, and out of the crevice a huge
chocolate-brown Pixie was stealthily peeping! The door was semi-circular
in form, its edge beautifully beveled and covered with fine white silk,
and fitted into the ground as smoothly as a cork into a flask. The top
was covered with grass and ferns of the same kind as those on the ridge,
so that the keenest eye could not detect the difference. A hinge of
strong silk cloth held the trap-door to the upper side of the ridge.
All this the Brownies took in at a glance.[BA]

They crouched motionless in the bush, concealed by the leaves, but
having a full view of the monster who was slowly emerging from the
tubular burrow under the trap. The creature was the largest of the Pixie
race that either of