"They gave them to me at the post office," stammered Sam.
"Did you give the number of my box?"
"Yes, sir."
"What number did you call for?"
"I don't remember," answered Sam, abashed.
"Then you don't remember the number of my box?"
"I don't remember now," Sam admitted.
"Did you call for No. 776?"
"Yes," said Sam, promptly.
"That's not the number," said the merchant, quietly. "You must return these letters instantly, and call for my mail. I will give you the number of my box on a card, and then you can't make any mistake. You have made a blunder, which must not be repeated."