and Frank and Billy agreed to take the second one. Nothing had
occurred when Ben, at midnight, aroused Frank and the young reporter
and told them it was time to go on duty.

The boys had been on sentry duty for perhaps an hour with nothing but
the lapping of the waves against the shore of the floating island to
break the deep stillness, when suddenly both were startled by a
strange and terrible cry that rang through the forest.

With beating hearts they leaped to their feet and strained their ears
to see if they could ascertain the origin of the uncanny cry, but they
heard nothing more.

Hardly had they resumed their places by the fire, however, before the
wild screams rang out again.

"It's some human being," cried Frank.

"They are being killed or something!" cried the affrighted Billy
Barnes.

By this time Ben Stubbs and Harry had awakened and were sitting up
with scared looks on their faces.

"Seems to come from near at hand," suggested Ben.

Suddenly the yell sounded quite close, and at the same instant it was
echoed by the boys as a dozen or more dark forms dashed out of the
dark shades of the forest and rushed toward them. Half unnerved with
alarm at this sudden and inexplicable attack, Frank fired point-blank