"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, boys," said the young chief, as he followed the stenographer outside. There was an oil lamp in the driveway leading to the street, and Bert, pausing under it, pulled out the queer slip of paper, and showed it to Mort. "I thought maybe you might know something about this," he said. "Where did you get it?" "I picked it up right near where you saw me, under the window. Some one threw it out." "So, that's why you were there, eh? I couldn't imagine. I thought you were trying to find out something about that house of mystery." "So I was. Why did you warn me away?" "Because, as I told you, Muchmore was right there. I happened to see you when I was at work, in the place he has fitted up as an office, and I didn't want you to get into trouble. You were on his private land, and he would just as soon as not have you arrested." "I'm not afraid of that. But what do you make of this message?" Mort, who had not closely examined the paper before, started as he caught sight of it. "Why, that was written on my typewriter!" he exclaimed. "I mean on the one Muchmore bought for me to use. I can tell, because the letter 'e' prints a little bit out of alignment." "Who wrote it?" asked Bert. "What do you make of it?" "I don't know who wrote it. Some one must have gone to my typewriter when I was away, or maybe it was done at night." "Could it have been the old housekeeper?" asked Bert. "Maybe she is in trouble, and this looks like an appeal for aid." "No. Mrs. Blarcum is afraid to touch the machine. Besides, she doesn't even know how to put the paper in." "Muchmore wouldn't have tossed out a message like that, I suppose?" "No. Besides, he knows how to work the machine, and he'd use the proper lettering. Anyhow, he'd have no occasion to do such a thing." "Then what can it be?" inquired Bert, much puzzled.