“I wish you’d tell me one or two things that I don’t quite understand, Mr. Granger,” said Sleuth, as they retraced their steps through the woods. “For instance, there’s the mysterious ticking of the unseen clock in the hermit’s hut.”

Granger chuckled a bit. “I’ve got a clock hidden there,” he said. “I took pains to hide it well, too.”

“Very clever,” said Sleuth. “But how about the mysterious rappings?”

“You observed that the old hut has fallen over until it touches one of those tall pines. When the wind blows, I fancy two of the limbs of that tree must knock together, and the sound, communicated along the trunk of the tree, is like that made by someone knocking.”

“Um,” said Piper; “simple. But when we were in the old ranch the day of the thunder-shower, we heard a low moaning following those knocking sounds.”

“I have heard that likewise when there was enough wind to move the door of the hut on its rusty hinges. It’s really a shame that you should catch me at this job, my boy, for it’s liable to deprive me of a steady remuneration, and my story writing scarcely provides a satisfactory income.”

“The hotel people have been paying you,” declared Piper. “That’s it, eh?”

“Sure. As I told you boys when I visited your camp, this hotel, being located some distance from a convenient railway station, didn’t succeed very well at first. Its methods of advertising were strictly conventional, and it was I who suggested something better in that line. Having heard the fable of Lovers’ Leap and the story of Old Lonely, I placed before the hotel proprietors a scheme through which I felt confident their place could be made very popular and attractive. It was I who advised them to place the white cross upon the cliff, and I wrote for them the story of the Indian lovers, which they are now using in their printed advertising. I urged them furthermore to make the most of the superstitious belief of some people that this island was haunted, and I agreed to do a few ghost stunts. You can see how easy it was for me, in collaboration with the hotel people, to carry this thing through. Two of the men from the hotel boathouse were rowing that boat, and, had the others insisted on landing upon the island, they would have pretended they were too frightened to do so. But it’s all over now. My lucrative profession as a spook is busted.”

“Now, really, that’s too bad,” said Sleuth, feeling sorry for the man. “If I don’t tell——”

“But you will. You can’t keep it to yourself. I never saw a boy who could keep such a secret.”

“Is that so?” exclaimed Sleuth resentfully. “Perhaps, Mr. Granger, you haven’t got boys thoroughly sized up. There may be some who can’t keep their traps closed, but I want you to understand that I’m different.”

The man stopped and grasped Piper by the shoulder.

“Will you promise not to expose me—at least, not for a year?” he asked eagerly. “That would give me time enough. Another season at this ghost game ought to pack that hotel full, and I can get a regular monthly salary to do my part of the work.”

“I’ve always wanted to write stories,” said Sleuth shrewdly. “You seem to know something about that sort of business, and if you’ll put me wise to the game I’ll remain as dumb as an oyster about this spook trick.”

“You won’t tell your friends even?”

“Not a living soul,” vowed Piper.

“Well, I’m not sure that I can instruct you in the art of writing stories; I’ve a lot to learn myself. Nevertheless, I’ll do my best. If you have some natural ability in that line, it may be possible that you can write, but I can’t promise you any degree of success without knowing more of your talents.”

“It’s a bargain, Mr. Granger,” said Piper, putting out his hand in the darkness. “If you’ll do that, I’ll keep mum for a year or more, in case you ask it.”

They shook hands, sealing the pledge.

They had reached the canoe and were about to launch it when distant voices were heard calling:

“Sleuth—oh, Sleuth! Piper! Where are you?”

“Well, I’ll be hanged!” muttered the boy. “That’s some of my bunch. They’re over yonder somewhere. Confound their hides! Now I know who took my boat. Now I understand how I happened to be left here on this old island.”

The boys were still calling.

“You’d better answer them,” said Granger quickly. “Go to meet them. I’ll keep out of sight. Good by.”

“Good by, Mr. Granger. I’ll see you tomorrow about two o’clock at your cabin, if that’s agreeable.”

“That’s agreeable to me. Hustle now. Answer them quick.”

Piper hurried away, shouting a response to his friends, and when he reached the place where he had left his boat he saw them a short distance away upon the water. There were three of them. Two were in the canoe, while one occupied the boat Sleuth had hired.

“Well, it’s about time you fellows came back for me,” rasped Piper. “Thought you were playing a fine old game, didn’t you? You were having a lot of fun with me, weren’t you? Rather clever to sneak up and take my boat away, wasn’t it?”

“Gee!” said Springer, who was sitting in the boat. “Old Sleuthy is mighty hot under the cuc-collar.”

“Yes,” sneered Crane from the canoe; “I’ll bate he’s pretty nigh scat to death.”

“Oh, you will, will you?” scoffed Piper. “Well, don’t bet too much on it, for you’ll lose your money. You haven’t got nerve enough to come here even with somebody, but I’ve been all over the island alone.”

“Go ashore and take him off in the boat, Springer,” directed Grant. “He sure doesn’t seem very much frightened.”

Piper got into the boat as soon as Phil brought it to the shore.

“Just because you fellows are scarecrows yourselves,” he sneered, “you mustn’t get the idea that everyone else is a coward. Come on now, Springer, you can do the rowing as long as you have the oars. Let’s get to camp. I’m hungry for supper.”

“Sus-seen anything of the ghost?” asked Phil, with a laugh.

“Oh, piffle!” retorted Sleuth. “Ghosts don’t frighten me. Why, I’d be willing to stay alone all night on this island.”

“Yes, you would!” scoffed Springer, although he wondered that Sleuth betrayed no symptoms of perturbation other than those caused by resentment at the trick they had perpetrated upon him. “We’ve been waiting for you to holler. We took the boat and went round the little point yonder, where we’d be out of sight, and waited there.”

“Say,” called Crane from the canoe, “we heard a dog howlin’, and it seemed to be on the island, too. Did yeou hear it, Sleuth?”

“Sure,” was the careless answer; “I heard it. It was on the island, all right.”

“Pipe,” said Grant, “you’re really a wonder. I confess that I’ve never had you sized up just right. For pure, unadulterated nerve, you seem to have the rest of us roped and thrown.”

Sleuth’s chest expanded tremendously.

“You never can tell,” he retorted.

They were some distance from the island, making for the camp, in the vicinity of which the fire, tended by Stone, could be seen gleaming cheerfully, when suddenly, behind them, rose the long drawn howling of a dog, hearing which, Springer jerked nervously at the oars and put greater energy into his stroke.

“There it is!” he cried. “Great Scott! it mum-makes my blood run cuc-cold!”

“Your blood,” scoffed Sleuth—“your blood is about as thick as water.”

“Look!” said Phil.

They looked back. In the border of the pines a light like a gleaming eye winked at them several times and vanished. Piper was the only one who knew that it must be a strong electric torch with a reflector, operated by Mr. Charles Granger.

Sleuth kept his word to Granger; not even a hint of the real solution of the mystery did he breathe to his campmates. They wondered at his surprising courage, for, accepting their challenge to do so, he permitted them to place him on the island and leave him there alone late one afternoon, and there he remained until they came to take him off an hour before midnight.

“Spooks,” said Piper, “are really sociable and friendly when you come to know them well. You never heard of one of them actually hurting a live person. As far as Old Lonely was concerned, I think he must have been a pretty decent sort when he was alive, even though he was tempted to rob a bank, and I haven’t the slightest notion that he’d harm anyone now he’s dead.”

Every afternoon during the remainder of the outing Piper visited Mr. Granger at the latter’s cabin. He explained to his friends that the young author was teaching him to write stories, and their newly acquired respect for Sleuth’s courage prevented them from joshing him much about this. Indeed, he was permitted to do practically as he pleased around the camp, taking advantage of which, he allowed his companions to perform all the labor, while he lounged around and dreamed of the day when he would write a detective yarn that should make the fascinating tales of “Old Sleuth” seem tame and feeble by comparison.

Twice Granger came to the boys’ camp and spent a sociable hour with them. He and Piper seemed to be on the most friendly terms, and once they were detected laughing slyly over a joke that was not explained at that time to the rest of the boys.

Jim Simpson also came frequently with supplies from the farm, and sometimes he talked with Grant about cowboy life, for he still clung to the hope that he would follow such a career when he became his own master.

Peace was formally declared between Sile Crane and Carl Duckelstein, and more than once the Dutch boy fished unmolested from the point.

At last the end of the outing came, as the end to all pleasant things must come, and the boys pulled down their tent, packed up, and their outfit was transported to Pemstock by Carl. Ere leaving the camping ground, they paused to give a rousing cheer. And as they marched away Springer cast a regretful look over his shoulder in the direction of Spirit Island.

“Too bad,” he said. “You’ve got plenty of nerve, Sleuth, but it’s too bad you couldn’t solve the mystery of that old island.”

Piper simply smiled.

These experiences, of course, only increased Piper’s interest in solving mysteries and his belief in his own genius in that line. During the fall immediately following his adventures in the summer camp, the Sleuth scented a secret nearer home. With his usual caution he followed the scent and made deductions, and the results surprised even him. The story is all told in “The Great Oakdale Mystery,” the fifth volume of the Oakdale Academy Series.