Herbert stood gazing at the slip of paper in his hand. He did not know what to make of it. Then he looked up at the window whence it had been thrown. There was no sign of life there. Whoever had tossed out the mysterious message had disappeared again behind the dark shutters.

"Well, this gets me," murmured the boy. "I wonder what it means? Is it a joke; or something serious?"

Then another idea came to him.

"It's written on a typewriter!" he exclaimed. "I wonder if it could have been done by Mort Decker? Perhaps he is in trouble there with Muchmore. Maybe the man has him locked up. Had I better tell the authorities?"

Then, as he looked at the message again, he had a different thought.

"No, Mort couldn't have written it," he said to himself. "He knows how to work a typewriter, and he'd use capitals in the places where they belong. And, besides, this message isn't finished. Whoever wrote it had to stop before he was through. I wonder what the rest of that word is. 'Priso--' Maybe it's meant for 'poisoned' and it's spelled wrong. I wish--"

But the boy's thoughts were suddenly interrupted by a noise at a window over his head. Thinking the person who had thrown out the mysterious message was again about to open the shutters, Bert watched anxiously, but, instead, a window on the second floor opened and Mort Decker leaned out.

"Hello!" began Bert.

"Hush!" exclaimed Mort, placing his fingers over his lips as an additional signal of caution. "Get away from here, Bert; Mr. Muchmore is coming!"

"But," went on the boy, "I have--"

"Don't say a word. Hurry away. I'll try to see you to-night, at the barn. Go, before--"

He did not finish the sentence, but hurriedly shut the shutters, and closed the window. Bert took the hint, and glided into the woods, where he could not be observed. He gave one look back at the mysterious house, and once more he saw that the window, from which Mort had looked, was open. But the stenographer did not peer forth. Instead, the face of Muchmore appeared. The man looked around carefully, as if to see if anyone had been communicating with inmates of the house. Then, apparently satisfied, as he saw nothing suspicious, he pulled the shutters tightly together, and closed the window.

"Well, things are happening in a bunch," thought Bert, as he made his way toward the village. "First I get a queer message I can't make head or tail of, and then Mort warns me away from the house. I wonder what he wants to tell me to-night? It must have something to do with the Stockton place."

Bert almost wished that a fire alarm might come in, so that the time would pass more quickly. But the day dragged along, and there was no occasion for taking out either of the engines.

After supper, as was his custom, the young chief visited the two fire- houses, to see that both apparatuses were in readiness for a run in the night. The tanks were kept filled, and the lanterns were lighted as soon as it grew dark.

Bert first went to the town hall, where, in the basement, he found Vincent and several members of "Corps No. 2," as it was known.

"Well, boys, all ready for a blaze?" asked Bert. "How's the machine, Vincent?"

"All right, I guess. We thought we were going to have a run, a while ago."

"How's that?"

"Pile of shavings near Sagger's new butcher shop caught fire, and made a lot of smoke. He came running in here, and wanted us to take the engine out, but I saw it didn't amount to anything, and I didn't want to waste a lot of chemicals on a blaze like that."

"What did you do?"

"We put it out with a few pails of water. He could have done the same, only he was too excited."

"And he is the man who said the bucket brigade was good enough," observed John Boll.

"I guess he's changed his mind," remarked Bert. "I'm going over to Cole's barn," he added. "It's my night on duty."

Bert found Cole and several of his chums engaged in games of checkers and dominoes in the barn, which had been fitted up as much as possible like a fire-house. Bert greeted his chums, and then sat down, to await, with what patience he could, the promised arrival of Mort.

"I hope he comes," thought the boy. "I'd like to get at the bottom of this."

It was nearly nine o'clock when Mort looked in at the open door of the barn and nodded to Bert.

"I'll be back in a little while, b............