"Yes," nodded Bob.
"Then I turned and went down one side of the next street and back the other."
"What did you do with the letters?"
"I went up on the stoops, just like the postman, and left a letter on each step."
"Did you knock or ring the bell?"
"Oh, no."
"Why not? The postman does."
"Yes, I know that," said little Walter, "but I did it as a's'prise."
"Oh, a surprise?"
"Yes, s'prise. That's the first house," said Walter, pointing around the corner as they reached the next street.
Bob lowered Walter to a hitching-block, and went up the walk leading to the house before which he had halted.
"That's good," he said to himself, as he saw the end of an old envelope sticking out from half-way under the door.
"One of the twenty letters, anyway," added Bob, placing the envelope in his pocket, as he read the address of Miss Simmons upon it.
At the second house he saw no letter lying around the porch. A lady came to the door. She knew Bob.
"I am looking for a letter Miss Simmons' little nephew left on your doorstep," he said.
"Oh, yes. I saw him come in, and I thought it was a circular. Then I noticed Miss Simmons' name on it, and guessed the little fellow was up to some boyish prank. Here it is. I was going to return it to her."
Thus Bob went down one side of the street. At every place but one he found the letters where they had been left. At the one place a boy had found the letter, and carried it
