“But how are you going to do it?” asked Frank.

“We’ll search the island for him,” replied Will.  “Come on, we’ll start now.”

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 talked, while waiting for the time to retire.  The boys were to make the attempt to capture Prince.

CHAPTER XXIV

 The ghost caught

“When do you expect to hear about little Dodo?” asked Grace, as the girls sat together on a log in front of the fire, “like roosting chickens,” Will was ungallant enough to remark.

“Almost any day now,” replied Mollie.  “They were to wait for the most favorable time for the operation, and the specialist, so mamma wrote, could not exactly fix on the day.  But I am anxious to hear.”

“I should think you would be.  Poor little Dodo!  I’d give anything to hear her say now ’Has oo dot any tandy? ’”

“Don’t,” spoke Betty in a low tone to Grace, for she saw the tears in Mollie’s eyes.

“It was the strangest thing how Stone and Kennedy should turn out to be the two chaps in the auto,” remarked Will, to change the subject.  “And you have never let on that Grace was the girl on the horse?”

“Never,” answered Amy.  “Don’t say after this that girls can’t keep a secret.”

Frank was to watch the first part of the night, to be relieved by Allen, and the latter by Will.

“For, from what the girls say, Prince has been in the habit of coming rather late,” Will explained, “and he’s more likely to let me catch him than if you fellows tried it.  So I’ll take last watch.”

Frank’s vigil was unrewarded, and when he awakened Allen, who sat up, sleepy-eyed, there was nothing to report.  Allen found it hard work to keep awake, but managed to do so by drinking cold coffee.