“So that’s how you raised the fare to Chicago!” said Owen, with a smile of great relief. “Yes; and when I found that I could go, naturally I wanted to get back that letter; for I feared the effect it might have upon my brother.” “So you waited at the box until Pop Andrews came to collect the mail, and you prevailed upon him to violate the rules and let you have it, and he handed you the wrong letter,” said Owen. “So far, so good. And now, Dallas, when you found that you had the Reverend Doctor Moore’s pink envelope, with the hundred-dollar bill inside, what did you do with it?” “When I got to my room at the boarding house, I started to tear the letter up without opening it, still thinking, of course, that it was the one which I had sent Chester. When I caught sight of the money inside, and realized the mistake I had made, I was in a quandary. The hundred-dollar bill and the letter which the envelope contained were each in four pieces. I was afraid to go to the post office and explain how it had happened, because I knew that if I did so it would get Carrier Andrews into trouble for violating the rules. So I decided to cut some sticking plaster into small strips, and paste the pieces together. I made quite a neat job of it; then I addressed a fresh envelope, inclosed the patched-up letter and hundred-dollar bill, and dropped it into a mail box.” Owen drew a deep breath of relief. “And I suppose the envelope which you addressed was a white one?” “Yes. I didn’t have any pink ones at the boarding house.” “And that explains, of course, why they thought at Branch X Y that the letter was missing from the mail. Naturally they didn’t think to go through the white envelopes. No doubt by this time the Reverend Doctor Moore’s friend in Pennsylvania is in receipt of his hundred-dollar bill. Your explanation, Dallas, clears the mystery! What a gink I am not to have thought of that solution before!” But suddenly a puzzled look came to Inspector Sheridan’s face. “There’s one point that isn’t cleared up yet: If you got the wrong pink envelope, Dallas, what became of the right one? The letter which you sent to your brother ought to have been in the mail still.” “And so it was,” answered Dallas, with a smile. “When I reached here I found that Chester was already in receipt of it.” “But how could that be? They searched all through the mail at Branch X Y, and failed to find any square, pink envelope.” “The letter which Chester received was in a square, white envelope,” said Dallas. “I noticed that as soon as he showed it to me. And,” she went on, with a puzzled frown, “that’s something which I can’t understand at all. I know that it sometimes happens that in a box of colored stationery a white envelope will get mixed with the tinted ones, but I am ready to take oath that the envelope in which I inclosed Chester’s letter was pink. If it wasn’t so perfectly ridiculous I should be inclined to believe that it must have changed color while in the mail.”