e was
aware of its presence. Several people who have mysteriously disappeared
in this country are supposed to have lost their lives in that way."

This conversation made a deep impression upon Mark, and when the boys
started on horseback, one dark night towards the end of March, with the
intention of going on a fire hunt in this very "sink hole" country, he
said to Frank, as they rode along,

"How about those holes in the ground that your father told us about the
other night. Isn't it dangerous for us to go among them?"

"Not a bit of danger," answered Frank, "as long as you're on horseback.
A horse'll always steer clear of 'em."

When they reached the hunting-ground, and had lighted the pine-knots in
their fire-pans, Frank said,

"There's no use our keeping together; we'll never get anything if we
do. I'll follow that star over this way"--and he pointed as he spoke to
a bright one in the north-east--"and you go towards that one"--pointing
to one a little south of east. "We'll ride for an hour, and then if we
haven't had any luck we'll make the best of our way home. Remember that
to get home you must keep the North-star exactly on your right hand,
and by going due west you'll be sure to strike the road that runs up
and down the river. If either of us fires, the other is to go to him at
once, firing signal guns as he goes, and these the other must answer so
as to show where he is."

Mark promised to follow these instructions, and as the two boys
separated, little did either of them imagine the terrible circumstances
under which their next meeting was to take place.

Mark had ridden slowly along for some time, carefully scanning the lane
of light ahead of him, without shining a single pair of eyes, and was
beginning to feel oppressed by the death-like stillness and solitude
surrounding him. Suddenly his light disappeared, his horse reared into
the air, almost unseating him, and then dashed madly forward through
the darkness.

The fire-pan, carelessly made, had given way, its blazing contents had
fallen on the horse's back, and, wild with pain, he was running away.
All this darted through Mark's mind in an instant; but before he had
time to think what he should do, the horse, with a snort of terror,
stopped as suddenly as he had started--so suddenly as to throw himself
back on his haunches, and to send Mark flying through the air over his
head.

Thus relieved of his rider, the horse wheeled and bounded away. At