"Is this the way you have all your mail addressed, to the post office at Lentone or--"

"Some of the mail is addressed this way; some of it is addressed directly to me and is left in the mail box nailed up to a tree at the entrance to this trail."

"What will you do about this, Professor?"

"I ought to go, of course, but--"

"To New York?" wondered Jimmy. "You would think the kidnappers, would rather deal with you here. They run much more chance of being caught in New York than up here. It seems--"

He stopped and looked curiously at Matthews. The latter was staring intently out upon the water. Without taking his eyes from the object that engaged his rapt attention, he said tensely:

"Someone give me the binoculars, quick!"

Norah handed him the gla.s.ses. He carefully focused them and looked long and earnestly out upon the water. The three men and the young woman followed his gaze and saw only the usual scattered craft on the surface of the lake.

Matthews with a muttered exclamation, put down the gla.s.ses, s.n.a.t.c.hed an automatic from a drawer in a table and raced toward the little wharf, throwing over his shoulder:

"Be back soon."

The others followed him to the lake slowly. They saw him get into the sea sled to which the outboard motor was attached, start it and go roaring off in the direction toward which he had had his gla.s.ses focused. The anxious groups watched intently.

They saw one of the bobbing craft turn and go racing toward the opposite sh.o.r.e in a north-westerly direction, with Matthews in pursuit.

The watchers stood there with bated breath, being quite certain that this impromptu pursuit had something to do with Tommy's disappearance. Their sea sled was fast and Matthews was adept at handling it. To their dismay they saw the distance between Matthews and the other boat widening. The pace of Matthews' boat slowed; it stopped altogether. They saw Matthews tinkering with the motor. Then they saw him take up the oar and begin paddling back laboriously.

He hailed a pa.s.sing launch which towed him back to their wharf.

Matthews' face was grim drawn as he reached his friends. They looked their mute inquiry.

Matthews unscrewed the motor from its place and carried it up above the water line. Then he turned to face them.

"Somebody was watching us from that boat with a pair of gla.s.ses. I caught the flash of the sun on his lenses. There was one man in the boat. I couldn't get a good look at him, he wore a floppy, big-brimmed straw hat well over his face.

"My gas gave out when I went after him. This wasn't an accident or carelessness on my part either. I filled the tank yesterday afternoon. Someone punctured the tank during the night. The puppy barked during the night but he barks a lot at nothing. See!"

He turned the motor over and pointed to a place near the bottom of the tank, where they saw a small hole with the ragged edge of the metal glinting with a freshness that the rest of the metal did not have. He continued:

"It's not a sure thing I could have caught him, if I had gas; that was a pretty fast boat, faster than this I think."

"Will you recognize the boat if you see it again?" asked Jimmy.

Matthews shook his head slowly.

"I'm not sure. There's any number of sea sleds on this lake just like it. That's not the important thing though. I should have taken the gla.s.ses along. When my gas gave out I could have had a good look at their motor. There may be a lot of boats like that but not many motors that can develop that speed. It will be a simple thing to attach that motor to another boat."

He went on with grim irony: "That's simple enough. If we had ten thousand men we could comb the thirty-odd miles of lake and examine every motor on it, thus narrowing the search down to motors capable of a speed--why are they watching, why--"

"Yes," went on McCall, "why this, and why do they want Professor Brierly to go back to New York? Why in the name of common sense New York? Is it--is it--" his features lit up. "Is it because someone is interested in seeing that Professor Brierly does not interfere in the affairs of Camp Higginbotham in the next few days?"

There was no answer. Professor Brierly's bushy eyebrows were bristling. He was staring at the faces of the group unseeingly.

Jimmy burst out:

"This is more than a mere kidnapping. With the eyes of two countries focused on this section the kidnapping can be predicated on one of two hypotheses. The kidnappers are crazy or they want Professor Brierly in New York. Mac's guess seems a good one. They want Professor Brierly away from here; that's a cinch. They--"

"Jimmy," interrupted Matthews, "are you influenced in what you say by your hope that Professor Brierly will help solve the riddle of the Tontine groups and help your story?"

He obviously was still in the grim mood that was so apparent on his return from the futile chase. Jimmy did not answer the charge.

He was looking at Matthews gravely. Jack reddened under the stare.

"I'm sorry, Jim. That was rotten! But thinking of Tommy--" Jimmy nodded:

"All right, old man, forget it, you didn't say anything. But I am wondering about this request to go to New York. I can't help thinking there is something in this request that doesn't appear on the face of it." He turned to Professor Brierly: "What are you going to do, sir?" Professor Brierly looked mutely at Norah. She shook her head helplessly.

For the next twenty-four hours the group suffered that, which is hardest to bear under the circ.u.mstances, inactivity. Twenty-four hours after the receipt of the second note there came a third, on the familiar cheap notepaper. This time it was postmarked Lentone, Vermont. It read:

_"Professor Brierly was told to go to New York. We will not stand any fooling. Enclosed is a sample of what we will do. If he does not start at once more will follow."_

This time the note was addressed to Norah. Wrapped securely there was a small object in the strong envelope. Professor Brierly took the small object from her hand. It was a human tooth, a tooth with dried blood on it. It had the ragged roots characteristic of a baby tooth, when it comes out.

At this moment McCall stepped into the room. Norah turned to him impulsively and told him of the letter and the accompanying tooth.

"How horrible!" exclaimed McCall. "Professor, we must--"

"Yes, pretty bad," commented Professor Brierly, "something must be done, quickly. But, there is, as our friend Hale would say, something wrong with this picture. This tooth did not come from Thomas's mouth. It--"

"Not from Tommy's mouth?" repeated Norah.

"No, Mrs. Van Orden, you may be certain of that. The roots of a child's teeth undergo a certain amount of disintegration before it is ready to give place to the permanent teeth. We will not go into the mechanical and biological reasons for this destruction; it is not important. While this is a deciduous tooth, I mean a baby tooth, it is not Thomas's tooth. How old is Thomas, Mrs. Van Orden?"

"He was just four and half years old yesterday."

Professor Brierly nodded his snow white head.

"Exactly, I thought so. No baby's tooth at that age shows the amount of disintegration that this tooth shows. Depend on it Mrs.

Van Orden, this tooth comes from the mouth of a child of not less than nine years of age."

The group was staring in wide-eyed astonishment. Norah asked tremulously.

"You are certain of what you say, Professor, that this is not Tommy's tooth."

"Depend on it, sis," interrupted Matthews. "Professor Brierly could not be mistaken in a thing like that. What I want to know is why--why this?"

There was an air of relief in the old scientist's demeanor. He still looked grim but he had the appearance of a man who has had a load lifted from him.

"I believe I know why. At any rate this solves one thing for us.

My advice is that we notify the police of the kidnapping. I do not think we can gain anything now by keeping quiet. I am also reasonably convinced that no harm can come to Thomas unless something unforeseen happens.