then eliminate all of the experiences that you can't absolutely and infallibly depend upon,—and see what you have left. It's worth trying."
Just then Dad came in and we went back to the thimble case. I showed him the one that we had picked out. "All right," said Dad; "You may have it at cost."
"But what is the cost?" I asked.
Dad looked disgusted. "Chet," he said, "you've known that cost mark for five years. What's the matter with you?"
"But this one can't be marked right," I said. "I know it cost more than a dollar and a half."
"Of course it did," said Dad.
"But see,—'m-a-q,'—that's what it's marked."
"Chet," he said, "haven't you any eyes or any reasoning powers at all? Don't you see that little '2' up there above the last letter?"
"Yes; but what does it mean?"
"Well, what should it mean excepting that it cost just twice what the mark says? Isn't that plain enough?"
"Yes, when you know it," I said; "but you never did that before."
"Well, such a lot of people have come to know
