Changing from their bathing suits to more conventional garments, the
boys and girls at once began a tour of the island. But though it was
not very large, there were inaccessible places, and it must have been
in one of these that Prince hid during the day, for they neither saw,
nor heard anything of him.

"We've got to set a trap!" exclaimed Will.

"How?" asked Grace.

"Well, evidently he's been in the habit of coming around the tent to
get scraps of food. We'll leave plenty out to-night, and also some
oats. Then we'll watch, and when Prince comes I'll catch him."

The boys voted this plan a good one. They went over to Mr. Lagg's
store in the Gem to get a supply of fodder for the trap.

"A horse on the island!" exclaimed Mr. Lagg. So that's the ghost; eh?
Well, it's very likely, but it sort of spoils the story;

"A ghostly ghost-- a ghost in white
Appearing in the darkest night.
That it should prove a horse to be,
Most certainly amazes me."

"Good!" exclaimed Will, with a laugh. "You are progressing, Mr. Lagg."

A goodly supply of oats was placed in a box near the tent that
evening, and then the boys and girls sat about the camp-fire and