“I believe we’ve exhausted every possibility of a clew to the mystery in this spot,” declared Cub at the end of half an hour’s search.  “Let’s not waste any more time here.”

“What’ll we do next, then?” asked Bud.

“Go fishin’” Cub replied.

“I think that’s a good suggestion,” said Mr. Perry.  “We’ve concentrated our minds and efforts on this problem all day thus far, and a little relaxation probably will do us good.”

“Where’s the best place to fish?” Hal inquired.

“I think I know,” Bud replied.  “I found a place where we can climb down the bank to a dandy little beach while I was looking over my section of the island.  A little spur of land runs out at that point, so as to form a small bay, and the water there is quiet and looks deep.”

They returned to the camp and got their fishing tackle and soon were casting baited hooks into the bay.  Bud’s prediction as to the hopeful appearance of this place, from an angler’s point of view, proved well founded.  In less than an hour they caught more fish than they could eat at supper and breakfast.

After supper they formed a campfire circle in front of the tent—­without a fire, however, for the normal heat of the atmosphere was all that comfort could demand—­and held a further discussion of the situation and the problem with which they were confronted.

“I don’t know, boys, but we ought to make a trip somewhere in the Catwhisker and get police help to solve this problem,” Mr. Perry remarked with a reflection of years and judgment in his countenance.  “Hal’s cousin may be in serious trouble, for all we know, and it’s our duty to enlist every agency at our command to aid him.”

“But while we’re gone something might develop here that would throw light on the mystery,” said Bud.  “Excuse me, Mr. Perry, for insisting on calling it a mystery.  I can’t think of it as anything else.”

“Oh, goodness me!” returned the one thus addressed.  “I’m afraid you boys failed to get what I was driving at.  I didn’t mean there was no such thing as mystery.  That depends on your point of view.  It is only people who are easily startled or confused by unusual things who are easily mystified.  I don’t mean to say that it would be impossible to mystify me under any circumstances.  For instance, if the man in the moon should suddenly jump down on the earth and give me a brick of green cheese, and then jump back again before I could say ‘thank you’ I presume I’d be greatly mystified.”

“Your illustration won’t stand a test of reason, dad,” Cub objected.  “To test whether it is possible for you to be mystified you must offer a test that is possible.”

“That’s precisely why I offered that impossible illustration,” Mr. Perry smiled.  “I wanted to see if any of you boys would catch the inconsistency.  You just call this affair a mystery as long as you think it is one, but after it is cleared up, I fancy you’ll have difficulty in looking back and picturing it as a mystery in your minds.  But I didn’t intend to take us off our subject.  I was going to answer Bud’s argument that something of importance might develop while we were gone.  Yes, that is true, but it wouldn’t be necessary for all of us to go.  Two of us might make the trip and the other two remain here.”